INTEGRATED SYSTEM FOR HEATING WATER

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/704,176, filed on 7 Oct. 2024, and U.S. Provisional Application No. 63/680,508, filed on 7 Aug. 2024, each of which is incorporated in its entirety by this reference.

TECHNICAL FIELD

This invention relates generally to the field of water heating systems operations and, more specifically, to a new and useful integrated system for heating water.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic representation of a system;

FIG. 2 is a schematic representation of one variation of the system;

FIG. 3 is a schematic representation of one variation of the system;

FIG. 4 is a schematic representation of one variation of the system;

FIG. 5 is a flowchart representation of a method;

FIG. 6 is a flowchart representation of one variation of the method;

FIG. 7 is a flowchart representation of one variation of the method;

FIG. 8 is a flowchart representation of one variation of the method;

FIG. 9 is a flowchart representation of one variation of the method;

FIG. 10 is a flowchart representation of one variation of the method;

FIG. 11 is a flowchart representation of one variation of the method;

FIG. 12 is a flowchart representation of one variation of the method;

FIG. 13 is a flowchart representation of one variation of the method;

FIG. 14 is a flowchart representation of one variation of the method;

FIG. 15 is a flowchart representation of one variation of the method; and

FIG. 16 is a flowchart representation of one variation of the method.

DESCRIPTION OF THE EMBODIMENTS

The following description of embodiments of the invention is not intended to limit the invention to these embodiments but rather to enable a person skilled in the art to make and use this invention. Variations, configurations, implementations, example implementations, and examples described herein are optional and are not exclusive to the variations, configurations, implementations, example implementations, and examples they describe. The invention described herein can include any and all permutations of these variations, configurations, implementations, example implementations, and examples.

1. System

As shown in FIGS. 1-5, a water heater 100 includes: a housing 102; a cold water inlet 104 arranged on the housing 102 and fluidly coupled to a cold water supply of a building; a water tank 108 arranged within the housing 102 and configured to store water received from the cold water supply via the cold water inlet 104; a heat pump 120 arranged within the housing 102 and configured to heat water stored in the water tank 108; an inline heater 140 arranged within the housing 102 and configured to heat water exiting the water tank 108; a hot water outlet 106 arranged on the housing 102 and configured to fluidly couple the water tank 108 to hot water supply lines within the building; and a mixing valve 150 arranged within the housing 102 and configured to combine cold water from the cold water supply of the building with hot water between the water tank 108 and the hot water outlet 106.

The water heater 100 is configured to, at a first time, detect a first water temperature of water stored in the water tank 108. The water heater 100 is also configured to, at the first time, in response to flow of water from the water tank 108 and in response to the first water temperature approximating a target supply temperature, supply hot water, proximal the target supply temperature, from the water tank 108 to the building.

The water heater 100 is further configured to, at a second time, detect a second water temperature of water stored in the water tank 108. The water heater 100 is also configured to, at the second time, in response to flow of water from the water tank 108 and in response to the second water temperature falling below the target supply temperature, trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature.

The water heater 100 is also configured to, at a third time: detect a third water temperature of water stored in the water tank 108; and, in response to flow of water from the water tank 108 and in response to the third water temperature exceeding the target supply temperature, at the mixing valve 150, combine cold water with hot water, exiting the water tank 108 proximal the third water temperature, to cool water exiting the water heater 100 toward the target supply temperature.

1.1 Variation: Water Heater with Heat Pump+Mixing Valve

As shown in FIGS. 1-4 and 7, in one variation, the water heater 100 includes: a housing 102; a cold water inlet 104 arranged on the housing 102; a water tank 108 arranged within the housing 102 and configured to store water received from a cold water supply of a building via the cold water inlet 104; a heat pump 120 arranged within the housing 102 and configured to heat water stored in the water tank 108; a hot water outlet 106 arranged on the housing 102; and a mixing valve 150 arranged within the housing 102 and configured to combine cold water from the cold water supply with hot water exiting the water tank 108.

The water heater 100 is configured to, at a first time: detect a first water temperature of water stored in the water tank 108; and, in response to the first water temperature approximating a target supply temperature, supply hot water, proximal the target supply temperature, from the water tank 108 to the building.

The water heater 100 is further configured to, at a second time: detect a second water temperature of water stored in the water tank 108; and, in response to flow of water from the water tank 108 and in response to the second water temperature exceeding the target supply temperature, at the mixing valve 150, combine cold water with hot water, exiting the water tank 108 proximal the second water temperature, to cool water exiting the water heater 100 toward the target supply temperature.

1.2 Variation: Water Heater with Heat Pump+Inline Heater

As shown in FIGS. 1-4 and 6, in one variation, the water heater 100 includes: a housing 102; a water tank 108 arranged within the housing 102 and configured to store water received from a cold water supply of a building; a heat pump 120 arranged within the housing 102 and configured to heat water stored in the water tank 108; a hot water outlet 106 arranged on the housing 102; and an inline heater 140 arranged within the housing 102 and configured to heat water exiting the water tank 108.

In this variation, the water heater 100 is configured to, at a first time, detect a first water temperature of water stored in the water tank 108. The water heater 100 is also configured to, at the first time, in response to flow of water from the water tank 108 and in response to the first water temperature approximating a target supply temperature, supply hot water, proximal the target supply temperature, from the water tank 108 to the building.

The water heater 100 is further configured to, at a second time, detect a second water temperature of water stored in the water tank 108. The water heater 100 is also configured to, at the second time, in response to flow of water from the water tank 108 and in response to the second water temperature falling below the target supply temperature, trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature.

1.3 Variation: Water Heater with Heat Pump+Resistive Heaters

As shown in FIGS. 1-4 and 8, in one variation, the water heater 100 includes: a housing 102; a water tank 108; a cold water inlet 104 arranged on the housing 102 and configured to couple a water supply of a building to the water tank 108; a hot water outlet 106 arranged on the housing 102 and configured to couple the water tank 108 to hot water supply lines within a building; an air inlet 110 (e.g., a warm air inlet 110); and an air outlet 112 (e.g., a cooled air outlet 112).

The water tank 108 is arranged within the housing 102 and is configured to store water received from the water supply. The water tank 108 also includes: a set of tank temperature sensors 114 configured to output a set of signals representing water temperatures of water stored in the water tank 108; and a set of resistive heaters 130 configured to heat water stored in the water tank 108.

The water heater 100 further includes: a blower 178 configured to drive external air from the air inlet 110 to the air outlet 112; and a heat pump 120 arranged within the housing 102, including an evaporator 190 interposed between the air inlet 110 and the air outlet 112, and configured to transfer thermal energy from air entering the air inlet 110 into water stored in the water tank 108.

The water heater 100 further includes: a first fluid line segment coupled to the hot water outlet 106 of the water tank 108; an inline heater 140 configured to heat water passing through the first fluid line segment; a first temperature sensor 114 arranged downstream of the inline heater 140 and configured to output a first signal representing a first temperature of water passing through the first fluid line segment; a second fluid line segment coupled to a hot water outlet 106 of the first fluid line segment; and a mixing valve 150 arranged along the second fluid line segment and fluidly coupled to the cold water inlet 104. The mixing valve 150 is configured to mix cool water from the cold water inlet 104 with hot water passing through the second fluid line segment to cool water passing through the second fluid line segment to a target supply temperature. The water heater 100 further includes a second temperature sensor 114 configured to output a second signal representing a second temperature of water passing through the second fluid line segment.

The water heater 100 also includes a controller configured: to selectively activate the heat pump 120 to heat water stored in the water tank 108 based on the water temperature of water stored in the water tank 108 and an air temperature of ambient air; to selectively activate the set of resistive heaters 130 to heat water stored in the water tank 108; and to selectively activate the inline heater 140 to heat water exiting the water tank 108.

1.4 Variation: Ventilation and Air Handling

As shown in FIGS. 2 and 8, in one variation, the water heater 100 also includes: an air supply pipe configured to supply air from an external air source (e.g., outside of the building) to the air inlet 110; an air return pipe configured to return air from the air outlet 112 to the external air source; an air supply valve 122 configured to selectively couple the air inlet 110 to the air supply pipe and an interior space (e.g., a basement or utilities closet) occupied by the water heater 100; an air return valve 124 configured to selectively couple the air outlet 112 to the external air source (e.g., outside of the building, the air return side of the forced air heating and ventilation system, etc.) and the interior space; and an air temperature sensor 114 configured to output signals representing temperatures of air entering the air inlet 110.

In this variation, the controller can: trigger the air supply valve 122 to couple the air inlet 110 to the air supply pipe; and detect a first air temperature of air entering the air inlet 110 from the air supply pipe based on a first signal output by the air temperature sensor 114. In response to the first air temperature falling below a minimum heat pump operating temperature, the controller can: trigger the air supply valve 122 to couple the air inlet 110 to the interior space of the building; and detect a second air temperature of air entering the air inlet 110 from the interior space of the building based on a second signal output by the air temperature sensor 114. In response to the second air temperature falling below the minimum heat pump operating temperature, the controller can: deactivate the heat pump 120; and activate the set of resistive heaters 130 to heat water stored in the water tank 108.

In this variation, the controller can further detect a third air temperature of air proximal the water heater 100. In response to the third air temperature falling below a minimum local ambient air temperature (e.g., a temperature set by a user), trigger the air return valve 124 to couple the air outlet 112 to the external air source to direct cooled air, generated by the heat pump 120, toward the external air source. In response to the third air temperature exceeding the minimum local ambient air temperature, the controller can trigger the air return valve 124 to couple the air outlet 112 to the interior space to direct cooled air, generated by the heat pump 120, toward the interior space.

1.5 Variation: Leak Detection

As shown in FIGS. 1 and 13, in one variation, the water heater 100 also includes: an electromechanical shutoff valve 174 interposed between the cold water inlet 104 and the water tank 108; a pressure sensor 116 fluidly coupled to the water tank 108, arranged downstream of the electromechanical shutoff valve 174, and configured to output signals representing water pressures within the water tank 108 and hot water supply lines within the building; and a moisture sensor 118 configured to output signals representing water (or “moisture”) proximal a base of the housing 102.

In this variation, the controller is also configured to: trigger the electromechanical shutoff valve 174 to close; access a first set of signals output by the pressure sensor 116 and representing water pressures in hot water supply lines within the building the shutoff valve 174 in the closed position; and interpret a water leak, within the building and downstream of the water heater 100, based on a decay of water pressures represented in the first set of signals. Additionally, in this variation, the controller is further configured to: access a second signal output by the moisture sensor 118 and indicating presence of water proximal the base of the housing 102; and interpret a water leak within the water heater 100 based on the second signal.

1.6 Variation: Nominal and Limp Modes

As shown in FIGS. 2 and 6, in one variation, the water heater 100 also includes: a first power junction 180 configured to couple to a first power supply limited to a first amperage and supply power to the heat pump 120 and electrically isolated from the inline heater 140; and a second power junction 180 configured to couple to a second power supply limited to a second amperage greater than the first amperage and supply power to the heat pump 120 and the inline heater 140. In this variation, the controller is configured to: disable the inline heater 140 when power is supplied to the first power junction 180; and activate the inline heater 140 when power is supplied to the second power junction 180.

2. Method

As shown FIGS. 8-11, 15, and 16, a method S100 includes, during a first time period: predicting a first estimated time until a first hot water consumption event within a building in Block S102; accessing a first water temperature of water stored in a water tank 108 of a water heater 100 supplying hot water to the building in Block S110; accessing a target supply temperature for water supplied to the building by the water heater 100 in Block S106; and estimating a first heating duration to heat water stored in the water tank 108 to the target supply temperature based on a first difference between the first water temperature and the target supply temperature in Block S118.

The method S100 also includes: in response to the first estimated duration approaching the first heating duration, triggering a heat pump 120, arranged within the water heater 100, to heat water stored in the water tank 108 toward the target supply temperature in Block S120; and, at the water heater 100, supplying hot water, proximal the target supply temperature and stored in the water tank 108, to the building during the first hot water consumption event in Block S170.

The method S100 further includes, during a second time period, predicting a second estimated time until a second null hot water consumption window within the building in Block S104. The method S100 also includes, during the second null hot water consumption window: triggering the heat pump 120 to maintain water stored in the water tank 108 proximal a nominal temperature less than the target supply temperature in Block S120; and, at the water heater 100, in response to flow of water from the water heater 100, triggering an inline heater 140, interposed between the water tank 108 and an outlet of the water heater 100, to heat water exiting the water tank 108 toward the target supply temperature in Block S140.

2.1 Variation: Water Tank Capacity Extension

As shown FIGS. 9, 10, and 15, one variation of the method S100 includes, during a first time period: predicting a first estimated time until a first hot water consumption event within a building in Block S102; accessing a first water temperature of water stored in a water tank 108 of a water heater 100 supplying hot water to the building in Block S110; accessing a target supply temperature for water supplied to the building by the water heater 100 in Block S106; accessing a target holding temperature, exceeding the target supply temperature, for maintaining water stored within the water tank 108 in Block S108; and estimating a first heating duration to heat water stored in the water tank 108 to the target holding temperature based on a first difference between the first water temperature and the target holding temperature in Block S118.

This variation of the method S100 also includes: in response to the first estimated duration approaching the first heating duration, triggering a heat pump 120, arranged within the water heater 100, to heat water stored in the water tank 108 toward the target holding temperature in Block S120; and, at a mixing valve 150 arranged within the water heater 100, in response to flow of water from the water heater 100 during the first hot water consumption event, combining cold water with hot water, exiting the water tank 108 proximal the target holding temperature, to cool water to the target supply temperature in Block S150.

This variation of the method S100 further includes, during a second time period, predicting a second estimated duration of a second null hot water consumption window within the building in Block S104. This variation of the method S100 also includes, during the second null hot water consumption window: triggering the heat pump 120 to maintain water stored in the water tank 108 proximal a nominal temperature less than the target supply temperature in Block S120; and, at the water heater 100, in response to flow of water from the water heater 100, triggering an inline heater 140, interposed between the water tank 108 and an outlet of the water heater 100, to heat water exiting the water tank 108 toward the target supply temperature in Block S140.

2.2 Variation: Selective Heating Element Activation

As shown FIGS. 8-11, 14, and 15, one variation of the method S100 includes, during a first time period: predicting a first hot water consumption event within a building in Block S102; accessing a target supply temperature for water supplied to a building by a water heater 100 in Block S106; triggering a heating element arranged within the water heater 100 to heat water, stored in a water tank 108 of the water heater 100, toward the target supply temperature during a first heating duration preceding the first hot water consumption event; and, at the water heater 100, supplying hot water, proximal the target supply temperature and stored in the water tank 108, to the building during the first hot water consumption event in Block S170.

This variation of the method S100 also includes, during a second time period, predicting a second null hot water consumption window within the building in Block S104. This variation of the method S100 further includes, during the second null hot water consumption window: triggering the heating element to maintain water stored in the water tank 108 proximal a nominal temperature less than the target supply temperature; and, at the water heater 100, in response to flow of water from the water heater 100, triggering an inline heater 140, arranged within the water heater 100, to heat water exiting the water tank 108 toward the target supply temperature in Block S140.

2.3 Variation: Water Consumption Event Prediction

As shown FIGS. 14 and 15, one variation of the method S100 includes, during a calibration period: recording a timeseries of start times and hot water consumption volumes of hot water consumption within a building via a set of sensors integrated into a water heater 100; and aggregating the timeseries of start times and hot water consumption volumes into a hot water consumption forecast (or a “water consumption forecast”), the hot water consumption forecast including start times, end times, and hot water consumption volumes from the water heater 100 during an operating period succeeding the calibration period in Block S102.

This variation of the method S100 also includes, during the operating period: accessing an air temperature of air supplied to a heat pump 120 arranged within the water heater 100 in Block S112; accessing a water temperature of water stored in a water tank 108 of the water heater 100 in Block S110; and accessing a start time and a hot water consumption volume associated with a hot water consumption event from the water consumption.

This variation of the method S100 further includes, in response to the hot water consumption volume falling below a volume of water, stored in the water tank 108, proximal a target supply temperature: estimating a heating duration to heat water stored in the water tank 108 (e.g., calculating the energy required in joules) from the water temperature to the target supply temperature via the heat pump 120 based on the air temperature in Block S118; and activating the heat pump 120 at a heat pump activation time preceding a next start time of the hot water consumption event by at least the heating duration in Block S120. The method S100 also includes, following the start time of the hot water consumption event, deactivating the heat pump 120 in Block S122.

2.4 Variation: Predicted Water Consumption Volume Exceeds Tank Volume

As shown FIG. 11, one variation of the method S100 also includes, in response to the hot water consumption volume exceeding a total volume of the water tank 108: calculating a volume difference between the hot water consumption volume and the total volume of the water tank 108; and calculating a target holding temperature for maintaining water stored in the water tank 108, wherein the total volume of the water tank 108 at the target holding temperature mixed with the volume difference of cool water from a cold water supply of the building yields approximately the hot water consumption volume proximal the target supply temperature. This variation of the method S100 also includes: based on the air temperature, estimating a first heating duration to heat water stored in the water tank 108 from the first water temperature to the target holding temperature via the heat pump 120 in Block S118; and activating the heat pump 120 at a first time preceding the start time by at least the first time duration in Block S120.

This variation of the method S100 also includes, at a mixing valve 150 arranged within the water heater 100, in response to flow of hot water from the water heater 100 proximal a next start time of the hot water consumption event, combining cool water from the cold water supply with hot water exiting the water tank 108 to supply water to the building at the target supply temperature in Block S150. This variation of the method S100 also includes, following the start time of the hot water consumption event, deactivating the heat pump 120 in Block S152.

2.5 Variation: Water Consumption Outside of Forecast+Forecast Update

As shown FIGS. 9 and 10, one variation of the method S100 also includes, in response to detecting flow of hot water from the water heater 100 outside of hot water consumption events predicted in the water consumption forecast: accessing a water temperature of water stored in the water tank 108 in Block S110; in response to the water temperature falling below the target supply temperature, activating an inline heater 140 to heat water exiting the water tank 108 to the target supply temperature in Block S150; at the mixing valve 150, combining cool water from a cold water supply with hot water exiting the inline heater 140 to supply water at the target supply temperature in Block S150; and updating the hot water consumption forecast to include a start time and a hot water consumption volume outside of hot water consumption events predicted in the water consumption forecast. This variation of the method S100 also includes, in response to conclusion of the hot water consumption event, deactivating the inline heater 140 in Block S142.

2.6 Variation: Recirculation Controls

As shown FIG. 12, one variation of the method S100 includes, in response to a current time approaching a start time of a hot water consumption event predicted in the water consumption forecast, activating a recirculation pump 160 within a water heater 100 to circulate hot water from a water tank 108 of the water heater 100 to a set of fixtures arranged within a building in Block S160. This variation of the method S100 also includes deactivating the recirculation pump 160 immediately prior to the start time in Block S162.

2.7 Variation: Opportunistic Sterilization

As shown FIG. 12, one variation of the method S100 includes identifying a hot water consumption event predicted in a hot water consumption forecast for a building, the hot water consumption event: falling within a threshold time duration following a last cleaning module executed by the water heater 100; and characterized by a maximum hot water consumption volume in the hot water consumption forecast.

This variation of the method S100 also includes: accessing an air temperature of air supplied to a heat pump 120 arranged within the water heater 100 in Block S112; accessing a water temperature of water stored in a water tank 108 of the water heater 100 in Block S110; and accessing a start time and a hot water consumption volume associated with the hot water consumption event from the water consumption forecast.

This variation of the method S100 also includes: estimating a heating duration to heat water stored in the water tank 108 from the water temperature to a sterilization temperature, greater than the target supply temperature, via the heat pump 120 based on the air temperature in Block S118; accessing a minimum sterilization hold duration; and activating the heat pump 120 at a heat pump activation time preceding the start time by at least a sum of the heating duration and the minimum sterilization hold duration in Block S120.

This variation of the method S100 also includes, at the mixing valve 150, in response to flow of hot water from the water heater 100 proximal the start time of the hot water consumption event, combining cool water from a cold water supply with hot water exiting the water tank 108 to supply water at the target supply temperature in Block S150. This variation of the method S100 also includes, following the hot water consumption event, deactivating the heat pump 120 in Block S122. This variation of the method S100 also includes, prior to the start time of the hot water consumption event, activating the heat pump 120 to: heat water stored in the water tank 108 to the sterilization temperature; and maintain water stored in the water tank 108 above the sterilization temperature during the minimum sterilization hold duration in Block S120.

2.8 Variation: Heating Method Switching

As shown FIGS. 8, 14, and 15, one variation of the method S100 includes: accessing an air temperature of air supplied to a heat pump 120 arranged within a water heater 100 in Block S112; accessing a water temperature of water stored in a water tank 108 of the water heater 100 in Block S110; and accessing a start time and a hot water consumption volume associated with a hot water consumption event.

This variation of the method also includes, in response to the hot water consumption volume falling below a volume of water stored in the water tank 108 proximal a target supply temperature and in response to the air temperature falling below a threshold temperature: estimating a heating duration to heat water stored in the water tank 108 from the water temperature to the target supply temperature via a set of resistive heaters 130 (e.g., an electric immersion heater) arranged within the water tank 108 (i.e., rather than via the heat pump 120) in Block S118; and activating the set of resistive heaters 130 at a first time preceding the start time of the hot water consumption event by at least the heating duration in Block S130. The method S100 also includes, following the start time of the hot water consumption event, deactivating the set of resistive heaters 130 in Block S132.

3. Applications

Generally, the water heater 100 includes a set of integrated components arranged within a housing 102 and including: a water tank 108 configured to store water; a cold water inlet 104 fluidly coupling a cold water supply of a building to the water tank 108; a hot water outlet 106 fluidly coupling an outgoing hot water supply from the water heater 100 to hot water supply lines within the building; a heat pump 120 and a set of resistive heaters 130 configured to heat water stored in the water tank 108; an inline heater 140 configured to rapidly heat water exiting the water tank 108; a mixing valve 150 configured to mix cold water from the cold water supply with hot water exiting the water tank 108 and/or the inline heater 140; and a controller configured to selectively activate the set of resistive heaters 130, the heat pump 120, and/or the inline heater 140 to heat water supplied to the building.

In one application, the water heater 100 can selectively trigger one or more heating elements to pre-heat water stored in the water tank 108 to a target supply temperature (e.g., 120° Fahrenheit) for water supplied to the building. Generally, the water heater 100 can prioritize activation of the heat pump 120 (e.g., rather than the set of resistive heaters 130) to heat water based on the relative efficiency of the heat pump 120 (e.g., up to four times more efficient than resistive heating). However, the heat pump 120 requires a minimum threshold of thermal energy in the air supply to transfer heat to water stored in the water tank 108, such that operation of the heat pump 120 may be constrained by low ambient air temperatures (e.g., below 50° Fahrenheit). Accordingly, when the temperature of air supplied to the heat pump 120 falls below a minimum threshold for heat pump 120 operation, the controller can activate the set of resistive heaters 130 to heat water stored in the water tank 108. Accordingly, the water heater 100 can implement the heat pump 120 and/or the set of resistive heaters 130 to pre-heat water (e.g., prior to hot water demand), such that the water heater 100 maintains heating capability regardless of ambient constraints. Therefore, the water heater 100 can consistently and reliably supply hot water to the building.

In another application, the water heater 100 can monitor temperatures of water exiting the water tank 108 and selectively activate heating elements and/or the mixing valve 150 to supply water to the building at the target supply temperature. For example, the water heater 100 can supply hot water directly from the water tank 108 when the temperature of water stored in the water tank 108 approximates the target supply temperature. In this example, the water heater 100 can withhold activation of the heating elements to minimize energy consumption when water can be directly supplied to the building from the water tank 108.

Alternatively, the water heater 100 can rapidly heat water exiting the water tank 108 (i.e., “on demand”), such as when the temperature of water stored in the water tank 108 falls below the target supply temperature. In particular, the water heater 100 can trigger the inline heater 140 to rapidly heat water exiting the water tank 108 toward the target supply temperature. Additionally or alternatively, the mixing valve 150 can selectively actuate to mix cold water with hot water exiting the water tank 108 (or the inline heater 140) to cool (i.e., reduce the temperature of) water to the target supply temperature.

Accordingly, the water heater 100 can increase the hot water supply capacity beyond the total storage volume of the water tank 108 by: heating water stored within the water tank 108 (e.g., via the heat pump 120 and/or the set of resistive heaters 130) to a temperature exceeding the target supply temperature and implementing the mixing valve 150 to cool water exiting the water tank 108 to the target supply temperature; or heating water exiting the water tank 108 to a temperature exceeding the target supply temperature via the inline heater 140 and implementing the mixing valve 150 to cool water exiting the inline heater 140 to the target supply temperature. More specifically, by maintaining water at a higher temperature within the water tank 108 and/or heating water via the inline heater 140, the water heater 100 can mix a greater volume of cold water at the outlet to achieve the target supply temperature, thereby increasing the amount of deliverable hot water per unit volume stored. For example, the water heater 100 can temporarily increase the hot water supply capacity during high-demand intervals to prevent hot water shortages within the building. Therefore, the water heater 100 can increase hot water capacity, such as during high-demand periods, while maintaining consistent outlet temperature of water supplied to the building and preventing scalding at downstream fixtures.

Accordingly, the water heater 100 can: withhold activation of the heating elements when the temperature of water stored in the water tank 108 approximates the target supply temperature; rapidly heat water exiting the water tank 108 via the inline heater 140 when the temperature of stored water falls below the target supply temperature; and, via the mixing valve 150, cool water exiting the water heater 100 when the temperature of water exiting the water tank 108 (or the inline heater 140) exceeds the target supply temperature. Therefore, the water heater 100 can maintain continuous availability of hot water within the building, reduce latency in delivering hot water to fixtures, and reduce water waste resulting from users purging cooled water from hot water supply lines while waiting for hot water.

3.1 Water Consumption Event Prediction

Generally, the method S100 can be executed by the water heater 100: to predict a hot water consumption event that will occur within the building; to estimate a heating duration to heat water stored in the water tank 108 for this hot water consumption event; to trigger one or more heating elements to heat water stored in the water tank 108 during the heating duration, such that hot water is available to the building at a start of the hot water consumption event; and to supply hot water to the building during the hot water consumption event. In particular, the water heater 100 can prioritize activation of the heat pump 120 (i.e., rather than the set of resistive heaters 120) to pre-heat water stored in the water tank 108 in advance of predicted demand to reduce total energy consumption during water heating.

Additionally, by accurately predicting timing of hot water demand within the building, the water heater 100 can selectively deactivate the heat pump 120 during periods of inactivity (i.e., rather than maintaining a constant water temperature), allow water temperature in the water tank 108 to decay passively, and selectively reactivate the heat pump 120 prior to the next predicted hot water consumption event. Accordingly, the water heater 100 can: supply hot water proximal the target supply temperature coincident with actual demand, thereby maintaining user comfort and avoiding perceived hot water shortages; and minimize total energy consumption during water heating by prioritizing activation of the heat pump 120 to heat water in advance of predicted demand and avoiding unnecessary operation of the heat pump 120 during periods of inactivity.

In one application, the water heater 100 can predict the hot water consumption event within the building and estimate the heating duration to pre-heat water stored in the water tank 108 prior to the hot water consumption event. In particular, the water heater 100 can account for a relatively long heating duration of the heat pump 120 by initiating heating sufficiently in advance of the hot water consumption event, such that hot water is available to the building proximal the target supply temperature at the start of the hot water consumption event.

For example, the water heater 100 can monitor water consumption data (e.g., a time series of flow rate values) representing water consumption within the building. The water heater 100 can then identify recurring patterns or trends in hot water consumption (e.g., morning shower routines or evening dishwashing intervals) based on the water consumption data. In particular, the water heater 100 can predict timing of future hot water consumption events based on detection of recurring water consumption patterns that exceed a threshold volume and/or duration. More specifically, to predict hot water consumption events, the water heater 100 can filter isolated or low-volume usage events and detect patterns coinciding with specific time intervals and flow characteristics.

In one example, the water heater 100 can derive an average hot water consumption volume each Monday between 6:00 AM and 6:30 AM based on the water consumption data observed over the previous five Mondays, each weekday (i.e., Monday-Friday) over the previous 30 days, seasonal variations, and/or user inputs (e.g., user routines). The water heater 100 can then interpret the time window on Mondays between 6:00 AM and 6:30 AM as a hot water consumption event based on the average hot water consumption volume exceeding a threshold volume.

In another example, the water heater 100 can generate a set of historical demand templates representing prior instances of water usage. For example, the water heater 100 can: segment historical water consumption data into discrete intervals (e.g., daily intervals); and generate a set of demand templates, each demand template representing a water consumption pattern over a particular interval. For example, each demand template can include a first duration (e.g., 12 hours) for matching to current water consumption data and a second duration (e.g., 4 hours) for predicting future water consumption.

The water heater 100 can then: access a set of current flow rate data (e.g., the past 12 hours); match the current flow rate data to flow rate data represented in a best-matching demand template; and predict a future hot water consumption event based on water consumption represented in the best-matching template. Upon predicting the future hot water consumption event, the water heater 100 can estimate the heating duration to heat water stored in the water tank 108 to the target supply temperature based on a current water temperature and heating rate of the heat pump 120. The water heater 100 can then schedule activation of the heat pump 120 in advance of the predicted event based on the estimated heating duration and schedule deactivation of the heat pump 120 during periods of inactivity to reduce total energy consumption.

In one application, upon predicting a future hot water consumption event and estimating a heating duration, the water heater 100 can selectively trigger one or more heating elements to heat water prior to the hot water consumption event. In particular, the water heater 100 can prioritize activation of the heat pump 120 (e.g., a high-efficiency heating element) to heat water and selectively implement the set of resistive heaters 130 (e.g., a rapid heating mechanism) in response to air temperatures falling below the minimum threshold for heat pump 120 operation.

The water heater 100 can activate the heat pump 120 and/or the set of resistive heaters 130 prior to the start of the hot water consumption event by at least a sum of the heating duration (e.g., 30 minutes) and a buffer period (e.g., between ten to twenty minutes prior to the start time) to account for potential variability in heating performance or early demand. Furthermore, the water heater 100 can heat water stored in the water tank for the hot water consumption event in addition to an extra supply of water (e.g., such as with a safety factor of +10% of the predicted hot water consumption volume). Thus, the water heater 100 can account for fluctuations and/or deviations from the water consumption forecast by: heating extra water in addition to the predicted hot water consumption volume; and implementing a buffer period.

For example, for a hot water consumption event between 6:00 AM and 6:30 AM, the water heater 100 can: access a scheduled heat pump activation time at 5:00 AM (i.e., accounting for a 45 minute heating duration and a fifteen minute buffer period); and, at the scheduled heat pump activation time, detect an air temperature of 72° Fahrenheit. In response to the air temperature exceeding the minimum heat pump operating temperature of 65° Fahrenheit, the water heater 100 can activate the heat pump 120 to heat water to the target supply temperature. Alternatively, in response to the air temperature falling below the minimum heat pump operating temperature, the water heater 100 can: estimate a second heating duration of 20 minutes to heat water stored in the water tank to the target supply temperature via the set of resistive heaters 130; and activate the set of resistive heaters 130 at 5:30 AM (i.e., accounting for a 15 minute heating duration and a fifteen minute buffer period). Thus, the water heater 100 can: initialize water heating with enough time to operate the heat pump 120, thereby maximizing energy efficiency by leveraging ambient thermal energy to operate the heat pump 120 (e.g., up to four times more efficient than resistive heating); and reassign water heating to the set of resistive heaters 130 (i.e., in absence of ambient thermal energy from the external air supply), thereby maintaining the ability to rapidly heat water.

Furthermore, the water heater 100 can detect hot water consumption occurring outside of a predicted hot water consumption event and rapidly respond by activating one or more heating elements to restore water temperature toward the target supply temperature. In particular, the water heater 100 can: monitor water flow rates in real time; detect deviations from predicted consumption patterns; and automatically activate the heat pump 120, the set of resistive heaters 130, and/or the inline heater 140 to heat water. Additionally, the water heater 100 can update the predicted hot water consumption events responsive to consistent detection of new hot water consumption events. Therefore, the water heater 100 can maintain hot water availability in response to unplanned demand while improving the accuracy of future consumption predictions.

Accordingly, the water heater 100 can: automatically track hot water consumption within a building (e.g., a home); automatically predict hot water consumption start and stop times (i.e., hot water consumption events), flow rates, and/or hot water consumption volumes during these hot water consumption events; and automatically activate one or more heating elements to heat water prior to each hot water consumption event to supply hot water prior to each hot water consumption event.

3.2 Dynamic Ventilation

In another application, the water heater 100 can integrate with an HVAC system to augment the supply of warm and/or cooled air generated by the HVAC system. In particular, in this application, the water heater 100 can: supply the heat pump 120 with warm air via an air inlet vent coupled to a heating system of the building; and expel cooled air—generated by the heat pump 120 during the heating process—via an air outlet 112 coupled to a cold air supply (e.g., in an air conditioning system) of the building to supplement the cold air supply. Therefore, the water heater 100 can cooperate with the HVAC system to extract thermal energy from air previously heated by the HVAC system during a heating cycle, and concurrently supply cooled air generated by the heat pump 120 into a cold-air pathway of the building, thereby improving the overall efficiency of thermal energy transfer within the building.

3.3 Leak Detection

In another application, the water heater 100 can iteratively test for water leaks occurring outside of the water heater 100 (i.e., within the building) via an integrated pressure sensor 116. In this application, the water heater 100 can: interrupt the water supply to the building; deactivate the heating elements; and monitor signals output by the pressure sensor 116 to detect a change in water pressure within the hot water supply lines that indicates presence of a water leak. In response to detecting a pressure drop characteristic of a water leak, the water heater 100 can maintain interruption of the water supply and generate a notification for the user indicating the presence of the water leak. Therefore, the water heater 100 can execute automatic, pressure-based diagnostics to identify leaks within the building, thereby mitigating potential damage resulting from a water leak.

3.4 Energy Efficient Heating+User Comfort

In one application, the water heater 100 can efficiently heat and supply water to the building, while preserving user comfort and avoiding noticeable delays or shortages in hot water delivery. For example, the water heater 100 can trigger heating during time periods in which: energy supply to the building exceeds total building energy demand; excess electrical energy is available on the external power grid (e.g., during periods of renewable energy surplus); and/or energy costs fall below a threshold level (e.g., during off-peak utility billing hours). In this example, the water heater 100 can: pre-heat water stored in the water tank 108 to a target holding temperature that exceeds the target supply temperature; deactivate the heating elements following completion of the heating cycle; and allow the water to thermally decay toward the target supply temperature over time. Additionally or alternatively, the mixing valve 150 can mix high-temperature water stored in the water tank 108 with incoming cold water to achieve the target supply temperature at the hot water outlet 106. Accordingly, the water heater 100 can function as a thermal battery by storing thermal energy in advance of demand and discharging that energy during hot water consumption events.

In another example, the water heater 100 can selectively activate a recirculation pump 160 to recirculate stagnant water through the hot water lines and deactivate the recirculation pump 160 following completion of recirculation. In this example, the water heater 100 can preserve hot water availability at distal fixtures without unnecessary thermal or electrical losses.

Accordingly, the water heater 100 can maintain consistent hot water availability and preserve user comfort by: supplying water to the building at a target supply temperature; extending the effective volume of available hot water by mixing high-temperature water with cold water to mitigate risk of shortages during high-demand intervals; recirculating stagnant water within the hot water lines to reduce delays in hot water delivery at distal fixtures; cooling ambient air proximal the water heater 100 and/or within non-adjacent spaces within the building; and detecting leaks within or outside the housing 102 to mitigate water damage within the building. Therefore, the water heater 100 functions as a multi-modal, energy-efficient appliance that intelligently manages heating operations while delivering a consistent and responsive supply of hot water to the building.

4. Housing

In one implementation, the water heater 100 includes a housing 102 (i.e., an outer shell) that encapsulates an integrated set of components configured to store, heat, and distribute water, as shown in FIGS. 1-4. In particular, the housing 102 can encapsulate a set of components including: a water tank 108 configured to store water; a set of water heating elements (e.g., a heat pump 120, a set of resistive heaters 130, an inline heater 140); a set of sensors configured to output signals representing water temperatures, water pressures, etc.; and a controller configured to selectively trigger the set of components based on the signals output by the set of sensors. Accordingly, the housing 102 defines a structure configured to maintain spatial and functional integration of each component, thereby reducing installation complexity and avoiding performance inconsistencies associated with disparate or separately installed heating and plumbing subsystems.

5. Cold Water Inlet+Hot Water Outlet

Generally, the water heater 100 can install within a building and be configured to: receive water in the water tank 108 from a cold water supply of a building, such as a main water line drawing water into a home; and supply water to the building via a network of hot water supply lines within the building. In one implementation, the water heater 100 can include: a cold water inlet 104 (i.e., a fluid inlet) arranged on the housing 102 and fluidly coupling the cold water supply of the building to the water tank 108; and a hot water outlet 106 (i.e., a fluid outlet) arranged on the housing 102 and fluidly coupling the water tank 108 to the network of hot water supply lines within the building. Thus, the water heater 100 can receive cold water stored in the water tank 108 via the cold water inlet 104 and redistribute hot water from the water tank 108 via the hot water outlet 106.

6. Air Inlet+Air Outlet

In one implementation, the water heater 100 includes: an air inlet 110 arranged on the housing 102; an air supply valve 122 configured to selectively couple the air inlet 110 to an external air source (e.g., outside of the building) and an interior space of the building (e.g., a basement or utilities closet) occupied by the water heater 100; an air outlet 112 arranged on the housing 102; and an air return valve 124 configured to selectively couple the air outlet 112 to an external air source and the interior space of the building occupied by the water heater 100.

The water heater 100 can further include air temperature sensors 114 configured to output signals representing air temperatures proximal the water heater 100 and/or air temperatures of air entering the air inlet 110. The air supply valve 122 and the air return valve 124 can be configured to selectively couple the air inlet 110 and the air outlet 112, respectively, to the external air source and the interior space of the building based on air temperatures proximal the water heater 100 and/or air temperatures of air entering the air inlet 110, as described below.

In one variation, the water heater 100 can be configured to cooperate with an HVAC system of the building. In one example, the air inlet 110 can couple with a warm-air supply (e.g., from a heating system) of the HVAC system and draw warm air to the water heater 100 (i.e., to operate the heat pump 120). In another example, the air outlet 112 can couple with a cold air supply (e.g., from an air conditioning system) of the HVAC system and supply cooled air (i.e., generated by the heat pump 120) to the cold air supply.

7. Water Tank+Resistive Heaters

Generally, the water heater 100 includes a water tank 108 arranged within the housing 102 and configured to store water within a target water temperature range (e.g., 120° to 160° Fahrenheit). In one implementation, the water tank 108 can include: a set of one or more water temperature sensors 114 configured to output signals representing water temperatures of water stored in the water tank 108; and a set of resistive heaters 130 configured to heat water stored in the water tank 108. For example, the set of water temperature sensors 114 can be arranged on the water tank 108 proximal a side wall of the water tank 108, the cold water inlet 104, and/or the hot water outlet 106.

In one implementation, the water tank 108 can receive water from the cold water supply of a building. The incoming water can trigger a water temperature sensor 114 to output a signal representing the water temperature of water stored in the water tank 108. Based on the water temperature of water stored in the water tank 108, the water heater 100 can selectively activate a heating element to heat water), as described below. In one example, in response to the water temperature falling below a minimum water temperature (e.g., 120° Fahrenheit), the water heater 100 can selectively activate a heating element to heat water to the target temperature range (e.g., 120° to 160° Fahrenheit). The water heater 100 can repeat this process to maintain the water temperature within the target temperature range when cold water is supplied to the water tank 108 and/or while the water heater 100 is in standby (i.e., not supplying water to the building).

In one variation, to maintain the water temperature within the target temperature range, the water tank 108 can include a layer of insulating material (e.g., rigid foam, fiberglass, etc.): circumscribing the water tank 108; and configured to mitigate thermal energy loss from water stored in the water tank 108.

8. Heat Pump

In one implementation, as shown in FIGS. 1-3, the water heater 100 can include a heat pump 120 arranged within the housing 102 and configured to extract thermal energy from the external air supply to heat water stored in the water tank 108. In particular, the heat pump 120 can include: an evaporator 190 coil interposed between the air inlet 110 and the air outlet 112 and including a refrigerant configured to absorb thermal energy from the external air supply; a compressor 192 (e.g., a variable speed compressor 192) configured to compress (i.e., heat) the refrigerant; and a condenser coil 196 configured to transfer thermal energy to the water stored in the water tank 108. For example, the water heater 100 can include a heat exchanger extending through a condenser coil 196 circumscribing the water tank 108, or a heat exchanger extending through a condenser coil 196 disposed within the water tank 108.

The water heater 100 can further include a set of (i.e., one or more) air temperature sensors 114 arranged within the housing 102 (e.g., proximal the air inlet 110) and configured to output signals representing air temperatures proximal the water heater 100 and/or air temperatures of air supplied to the heat pump 120. The water heater 100 can selectively activate the heat pump 120 to heat water stored in the water tank 108 based on signals output by the water temperature sensors 114 and the air temperature sensors 114. In particular, the water heater 100 can activate the heat pump 120 in response to detecting an air temperature of air supplied to the heat pump 120 exceeding a minimum heat pump operating temperature. More specifically, the water heater 100 can withhold activation of the heat pump 120 when the temperature of air supplied to the heat pump 120 is insufficient for the heat pump 120 to draw thermal energy from the air supply, as described below.

9. Inline Heater

In one implementation, the water heater 100 can include an inline heater 140 arranged within the housing 102 and configured to heat water between the water tank 108 and the hot water outlet 106. In particular, the water heater 100 can include: a first fluid line segment interposed between the water tank 108 and the hot water outlet 106 of the water heater 100; and the inline heater 140 (e.g., a heat exchanging coil) arranged along the first fluid line segment and configured to heat water passing through the first fluid line segment. The inline heater 140 can rapidly heat water (i.e., outside the water tank 108) to a maximum water temperature (e.g., between 160° and 180° Fahrenheit), independent of the temperature of water stored in the water tank 108.

Furthermore, the inline heater 140 can cooperate with a mixing valve 150 to combine or mix water, exiting the inline heater 140 and proximal the maximum water temperature, with cold water (e.g., between 40° and 70° Fahrenheit) to cool water to the target supply temperature. For example, the water heater 100 can: detect a first water temperature of the water exiting the water tank 108; and, in response to the first water temperature falling below the maximum water temperature, activate the inline heater 140 to heat water to the maximum water temperature. The water heater 100 can then: detect a second water temperature of the water exiting the inline heater 140 based on a signal output by a temperature sensor 114 arranged downstream of the inline heater 140; and, at the mixing valve 150, based on the second water temperature, combine cold water with water exiting the inline heater 140 to cool water to the target supply temperature.

Accordingly, the inline heater 140 can rapidly heat water exiting the water heater 100 to the target supply temperature or a maximum water temperature. By rapidly heating water along the first fluid line segment, the inline heater 140 can supplement the volume of hot water available to the building, particularly during unexpected or high-demand periods that exceed stored capacity in the water tank 108. Therefore, the water heater 100 can maintain consistent delivery of hot water to the building by coordinating the set of heating elements to accommodate both predicted and unpredicted hot water consumption events.

10. Mixing Valve

In one implementation, the water heater 100 includes the mixing valve 150 configured to combine cold water with hot water between the water tank 108 and the hot water outlet 106 to decrease the temperature of water exiting the water heater 100 to the target supply temperature. In particular, the mixing valve 150 is arranged within the housing 102 and fluidly coupled to a cold water supply, such as the cold water supply of the building; and/or a cold water supply of a recirculation pump 160.

In one example, the water heater 100 can include: a second fluid line segment interposed between an outlet of the first fluid line segment and the hot water outlet 106 of the water heater 100; and a mixing valve 150 arranged along the second fluid line segment and fluidly coupled to a cold water supply. In this example, the water heater 100 can: detect a water temperature of water exiting the inline heater 140; and, in response to the water temperature exceeding the target supply temperature, activate the mixing valve 150 to combine cold water with water exiting the inline heater 140 to cool water to the target supply temperature.

Accordingly, the integrated inline heater 140 and mixing valve 150 can cooperate to: rapidly heat water exiting the water tank 108; and regulate temperature at the hot water outlet 106 by dynamically combining hot and cold water. Therefore, the mixing valve 150 can reduce the temperature of hot (e.g., overheated) water to prevent scalding at downstream fixtures, while extending the available volume of hot water by reducing reliance on stored tank volume alone.

In another variation, in response to detecting failure (e.g., mechanical failure) of the mixing valve 150, the water heater 100 can activate a shutoff valve 174 (e.g., an electromechanical shutoff valve 174) to interrupt the supply of hot water from the water heater 100 to the building. In particular, the water heater 100 can interrupt the supply of hot water to the building to prevent water from exiting the water heater 100 at a temperature (e.g., the maximum water temperature) exceeding the target supply temperature. Therefore, the water heater 100 can maintain output temperature control during component failure to mitigate risk of scalding at downstream fixtures.

10.1 Thermostatic Mixing Valve

In one variation, the water heater 100 can include a thermostatic mixing valve 150 configured to regulate the temperature of water supplied to the building, such as based on a water temperature specified by a user. In this variation, the thermostatic mixing valve 150 can include an adjustment mechanism configured to regulate the mixing ratio of hot water, exiting the water tank 108, and cold water from the cold water supply. In particular, the adjustment mechanism can be arranged on the housing 102 such that the adjustment can be accessed and adjusted by the user. More specifically, the user may set the adjustment mechanism to a particular position corresponding to a target supply temperature. The adjustment mechanism can then manually actuate the mixing valve 150 to mix cold water from the cold water supply with water between the water tank 108 and the hot water outlet 106 based on the target supply temperature.

In another variation, the controller can interpret the target supply temperature based on the position of the adjustment mechanism. In particular, the controller can: detect the position of the adjustment mechanism (i.e., a position set by the user); and automatically actuate the mixing valve 150 to mix cold water from the cold water supply with water between the water tank 108 and the hot water outlet 106 based on the target supply temperature.

11. Recirculation Pump

In one implementation, the water heater 100 include a recirculation pump 160 arranged within the housing 102 and configured to recirculate water within the building (i.e., water that has exited the water heater 100). In particular, the recirculation pump 160 can purge water (i.e., stagnant, unused, or cooled water) from hot water supply lines of the building with water stored in the water tank 108 and proximal the target supply temperature to reduce hot water delivery latency at fixtures throughout the building.

The recirculation pump 160 can cooperate with temperature sensors 114, arranged throughout the building, configured to output signals representing water temperatures within hot water supply lines within the building. In particular, in response to detecting a water temperature in a hot water supply line falling below a threshold water temperature, the water heater 100 can trigger the recirculation pump 160 to purge cooled water from the hot water supply line with water stored in the water tank 108 and proximal the target supply temperature. The water heater 100 can then deactivate the recirculation pump 160 in response to detecting that the water temperature within the hot water supply line exceeds the threshold water temperature, thereby reducing energy consumption associated with recirculation and preventing unnecessary operation of the pump.

For example, a temperature sensor 114 arranged proximal a shower supply line (e.g., in a home) can output a signal representing a water temperature of 90° Fahrenheit proximal the shower supply line. In response to the water temperature falling below a threshold temperature of 100° Fahrenheit, the recirculation pump 160 can purge the shower supply line with a supply of water proximal 100° Fahrenheit. Alternatively, in absence of water temperature sensors 114 arranged throughout the building, the recirculation pump 160 can recirculate water according to a schedule (e.g., every 30 minutes for the shower supply line), a water consumption forecast, and/or a digital model representing fixtures in the building.

In one variation, the recirculation pump 160 can direct the cooled water to the inline heater 140 for reheating, rather than the water tank 108. In particular, in this variation, in response to flow of water from the water tank 108, the water heater 100 can: trigger the recirculation pump 160 to draw cooled water from the building to the water tank 108; trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature; and supply hot water, exiting the hot water outlet 106 proximal the target supply temperature, to the building. In another variation, the recirculation pump 160 can direct the low cooled water to the mixing valve 150 for the mixing valve 150 to implement as the source of cold water (e.g., rather than drawing a supply of cold water from the cold water supply of the building). Therefore, the water heater 100 can leverage the suite of integrated components to maintain water, in hot water supply lines within the building, proximal the target supply temperature, thereby reducing delays in hot water availability at the fixture, minimizing thermal energy loss during standby periods, and limiting water waste during initial hot water demand intervals (e.g., when the user runs water at the fixture while waiting for hot water).

11.1 Variation: Thermal Valve

In one variation, the water heater 100 can cooperate with a thermal valve interposed between a hot water supply line and a cold water return line of a fixture within the building and configured to redirect cooled water from the hot water supply line to the cold water return line. In particular, in this variation, the water heater 100 can include a recirculation pump 160 arranged within the housing 102 and interposed between the cold water inlet 104 and the water tank 108. In this variation, at the fixture, in response to a water temperature in the hot water supply line falling below a threshold temperature, the thermal valve can actuate to direct cooled water from the hot water supply line to the cold water return line. The recirculation pump 160 can then: draw the cooled water to the water tank 108 via the cold water inlet 104; and redistribute a supply of water, proximal the target supply temperature, to the hot water supply line.

11.2 Variation: Recirculation Inlet

In one variation, the water heater 100 can include: a recirculation inlet 164 arranged on the housing 102; and the recirculation pump 160 arranged within the housing 102 and interposed between the recirculation inlet 164 and the water tank 108. In this variation, the recirculation pump 160 can: draw the cooled water to the water tank 108 via the recirculation inlet 164; and redistribute a supply of water, proximal the target supply temperature, to the hot water supply line.

12. Integrated Drainage and Pressure Regulation Components

In one variation, the water heater 100 can include a vacuum breaker valve 176 arranged within the housing 102 and interposed between the cold water inlet 104 and the water tank 108. In this variation, the vacuum breaker valve 176 can be configured to supply air to the cold water line during drainage operations, thereby preventing negative pressure (e.g., vacuum conditions) that may damage components of the water heater 100 and/or draw contaminants into the water tank 108.

In another variation, the water heater 100 can include an expansion tank arranged within the housing 102 and interposed between the cold water inlet 104 and the water tank 108. The expansion tank can be configured to receive water displaced from the water tank 108 responsive to increases in water volume and pressure within the water tank 108 resulting from thermal expansion during heating cycles.

In another variation, the water heater 100 can include a condensate pump 172: arranged within the housing 102; fluidly coupled to the heat pump 120; and configured to discharge condensate generated by the heat pump 120 while heating water stored in the water tank 108. In particular, the condensate pump 172 can: collect water condensed from the air supply during the operation of the evaporator 190 coil of the heat pump 120; and direct the collected condensate toward a drain line or other designated outlet. For example, the condensate pump 172 can be activated in response to a water level within a reservoir or collection tray exceeding a threshold height. Therefore, the condensate pump 172 can mitigate water accumulation within the housing 102, such that the water heater 100 can continuously operate the heat pump 120 under high-humidity or high-efficiency heating cycles, without requiring manual drainage.

Accordingly, the water heater 100 can integrate a set of components, such as the vacuum breaker valve 176, expansion tank, and/or condensate pump 172, within a single housing 102, each arranged and configured to support core fluid and thermal operations of the water heater 100. Therefore, the water heater 100: reduces installation complexity by eliminating the need for external plumbing components and minimizing variability introduced by disparate or separately installed heating and plumbing subsystems; and increases operational reliability by reducing potential failure points associated with externally mounted or separately installed components.

13. Controller

In one implementation, the water heater 100 includes a controller configured to implement closed-loop controls to selectively activate and deactivate the set of integrated components (e.g., the heat pump 120, the inline heater 140) based on signals output by the suite of sensors. For example, the controller can selectively activate one or more heating elements (i.e., the set of resistive heaters 130, the heat pump 120, and/or the inline heater 140) based on water temperatures and air temperature of air proximal the water heater 100. In another example, in response to detecting a water leak, the controller can actuate a valve (i.e., an electromechanical shutoff valve 174) to interrupt the water supply to the building, thereby mitigating potential damage resulting from the water leak. In another example, the controller can selectively disable one or more components (e.g., the inline heater 140) based on a voltage of power supplied to the water heater 100.

14. Selective Heating Element Activation for Pre-Heating Water

Generally, the water heater 100 can prioritize activation of the heat pump 120 (i.e., rather than the set of resistive heaters 130) to heat water stored in the water tank 108 based on the relative efficiency of the heat pump 120 (e.g., up to four times more efficient than resistive heating). However, the heat pump 120 requires a minimum threshold of thermal energy in the external air supply to transfer heat to the water stored in the water tank 108, such that operation of the heat pump 120 may be constrained by low ambient air temperatures (e.g., below 50° Fahrenheit). Thus, in response to detecting air temperatures below a minimum threshold for heat pump 120 operation, the controller can trigger the set of resistive heaters 130 to heat water stored in the water tank 108 toward the target supply temperature. Accordingly, the controller can selectively activate the heat pump 120, or the set of resistive heaters 130 based on ambient air conditions, such that the water heater 100 can maintain reliable heating performance across a range of environmental conditions.

In one implementation, the controller can: detect an air temperature of air entering the air inlet 110 (or air proximal the water heater 100) based on a signal output by an air temperature sensor 114; and, in response to the air temperature exceeding a minimum heat pump operating temperature (i.e., a threshold air temperature required for the heat pump 120 to draw thermal energy from the external air supply), trigger the heat pump 120 to heat water stored in the water tank 108 toward the target supply temperature.

In one example, incoming water from the water supply can trigger the controller to: detect a water temperature of 60° Fahrenheit of water stored in the water tank 108 based on a first signal output by a first temperature sensor 114 proximal the water tank 108; detect an air temperature of 72° Fahrenheit of air entering the air inlet 110 based on a second signal output by a second temperature sensor 114 proximal the air inlet 110; and, in response to the air temperature exceeding the minimum heat pump operating temperature of 65° Fahrenheit, activate the heat pump 120 to heat water stored in the water tank 108 to a target temperature (e.g., between 120° and 160° Fahrenheit). Thus, the water heater 100 can leverage ambient thermal energy from the air supply to implement the high-efficiency heat pump 120 to heat water stored in the water tank 108. Furthermore, the water heater 100 can concurrently expel cooled air, generated by the heat pump 120 during the heating process, to cool a space adjacent to the water heater 100, as described below.

Alternatively, the water heater 100 can implement the set of resistive heaters 130 to heat water stored in the water tank 108 when ambient conditions prevent operation of the heat pump 120. In one implementation, the controller can: detect an air temperature of air entering the air inlet 110 (or air proximal the water heater 100) based on a signal output by an air temperature sensor 114; and, in response to the air temperature falling below the minimum heat pump operating temperature, trigger the set of resistive heaters 130 to heat water stored in the water tank 108 toward the target supply temperature. Accordingly, in absence of ambient thermal energy from the air supply, the water heater 100 can activate the set of resistive heaters 130 to heat water stored in the water tank 108.

In one variation, the water heater 100 can selectively activate heating elements based on a current water temperature of water stored in the water tank 108, as shown in FIG. 10. For example, the water tank 108 may receive an influx of cold water from the cold water supply of the building, resulting in a significant water temperature drop. The controller can then: detect a difference between the water temperature of water stored in the water tank 108 and the target supply temperature; and selectively activate one or more heating elements based on this difference.

In particular, in this variation, the controller can: detect a water temperature of water stored in the water tank 108; and, in response to the water temperature falling below the target supply temperature by greater than a first threshold difference, trigger the heat pump 120 to heat water stored in the water tank 108 toward the target supply temperature. Alternatively, in response to the water temperature falling below the target supply temperature by greater than a second threshold difference, the controller can trigger the heat pump 120 and the set of resistive heaters 130 to heat water stored in the water tank 108 toward the target supply temperature. For example, the controller can: detect a water temperature of 50° Fahrenheit of water stored in the water tank 108; and, in response to the initial water temperature falling below the target supply temperature of 120° Fahrenheit by greater than a threshold difference of 60° Fahrenheit, activate the heat pump 120 and the set of resistive heaters 130.

Accordingly, the water heater 100 can dynamically activate one or more heating elements based on ambient conditions, such as the water temperature of water stored in the water tank 108 and the air temperature of air proximal the heat pump 120, to heat water toward the target supply temperature. Therefore, the water heater 100 can: prioritize energy efficiency by activating the heat pump 120 when thermal energy is available in the air supply; maintain continuous heating capability under a range of environmental and usage conditions by selectively activating the heat pump 120 and/or the set of resistive heaters 130; and consistently supply hot water to the building, regardless of demand fluctuations or ambient conditions that prevent operation of the heat pump 120.

15. Selective Heating Element Activation for On-Demand Heating

Blocks of the method S100 recite, in response to flow of water from the water heater 100: triggering the inline heater 140 to heat water exiting the water tank in Block S140; and, at the mixing valve 150, combining cold water with hot water, exiting the water tank 108, to cool water to the target supply temperature in Block S150. Blocks of the method S100 also recite, in response to detecting conclusion of flow of water from the water heater: deactivating the inline heater 140 in Block S142; and deactivating the mixing valve 150 in Block S152.

Generally, the water heater 100 can be configured to selectively activate the set of heating elements to heat and supply hot water to the building on demand, as shown in FIGS. 5-7. In particular, the water heater 100 can: trigger the inline heater 140 to rapidly heat water exiting the water tank 108; and, at the mixing valve 150, cool water exiting the water heater 100 to the target supply temperature by mixing cold water with hot water between the water tank 108 and the hot water outlet 106. The controller can selectively activate or deactivate these heating elements based on detected water temperature and flow conditions to meet real-time hot water demand without excessive energy consumption.

In one implementation, the water heater 100 can supply hot water directly from the water tank 108 when the water temperature of water stored in the water tank 108 approximates the target supply temperature. In this implementation, the water heater 100 can detect a water temperature of water stored in the water tank 108 based on a signal output by a temperature sensor 114 proximal the water tank 108 (e.g., via the controller). Then, in response to flow of water from the water tank 108 and in response to the water temperature approximating the target supply temperature, the water heater 100 can supply hot water, proximal the target supply temperature and stored in the water tank 108, to the building. Thus, in this implementation, the water heater 100 can reduce energy consumption by bypassing supplemental heating or cooling when the water tank 108 water temperature meets demand conditions, while supplying hot water at the target supply temperature without delay.

In another implementation, the water heater 100 can compensate for a relatively low water temperature in the water tank 108 by activating supplemental heating to achieve the target supply temperature. In this implementation, in response to flow of water from the water tank 108 and in response to the water temperature falling below the target supply temperature, the water heater 100 can: trigger the inline heater 140 to heat water exiting the water tank 108; at the mixing valve 150, combine cold water with hot water, between the water tank 108 and the hot water outlet 106, to cool water to the target supply temperature; and supply hot water, exiting the hot water outlet 106 proximal the target supply temperature, to the building. Thus, in this implementation, the water heater 100 can supplement water heating with inline heating to supply hot water at the target supply temperature when water exiting the water tank 108 is cooler than the target supply temperature.

In another implementation, the water heater 100 can compensate for a relatively high water temperature in the water tank 108 by disabling supplemental heating and combining cold water with hot water exiting the water tank 108 to cool water to the target supply temperature. In this implementation, in response to flow of water from the water tank 108 and in response to the water temperature exceeding the target supply temperature, the water heater 100 can: deactivate the inline heater 140; at the mixing valve 150, combine cold water with hot water, between the water tank 108 and the hot water outlet 106 and proximal the third water temperature, to cool water to the target supply temperature; and supply hot water, exiting the hot water outlet 106 proximal the target supply temperature, to the building.

In one variation, as shown in FIG. 11, in response to flow of water from the water tank 108, the water heater 100 can: trigger the inline heater 140 to heat water exiting the water tank 108 toward a maximum water temperature exceeding the target supply temperature; at the mixing valve 150, combine cold water with hot water, exiting the inline heater 140 proximal the maximum water temperature, to cool water to the target supply temperature; and supply hot water, exiting the hot water outlet 106 proximal the target supply temperature, to the building. Thus, the water heater 100 can extend the effective hot water supply capacity beyond the storage capacity of the water tank 108 by: heating water stored within the water tank 108 to a temperature exceeding the target supply temperature; heating water on demand via the inline heater 140; and regulating outlet temperature via the mixing valve 150.

In one variation, the water heater 100 can selectively activate the heating elements based on the magnitude of deviation between the water temperature in the water tank 108 and the target supply temperature. In this variation, in response to the water temperature falling below the target supply temperature by greater than a first difference (e.g., 15° Fahrenheit), the water heater 100 can trigger the set of resistive heaters 130 to heat water stored in the water tank 108 toward the target supply temperature. Alternatively, in response to the water temperature falling below the target supply temperature by greater than a second difference (e.g., 30° Fahrenheit), the water heater 100 can trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature.

Accordingly, the water heater 100 can selectively activate the inline heater 140 and/or set of resistive heaters 130 during hot water demand (i.e., regardless of whether water stored in the water tank 108 is at the target supply temperature). By dynamically activating these heating elements, such as based on flow detection and temperature deviation, the water heater 100 can supply hot water on demand without reliance on stored thermal energy. Therefore, the water heater 100 can prevent interruption of hot water delivery (e.g., during extended or unexpected draw events) and maintain outlet water temperature proximal the target supply temperature.

16. Dynamic Ventilation

In one variation, as shown in FIG. 8, the water heater 100 can be configured to dynamically supply air to the heat pump 120 from multiple air sources (e.g., ambient indoor air and an external air supply) to maintain thermal input conditions required to operate the heat pump 120. In particular, the water heater 100 can include an air supply valve 122 configured to selectively couple the air inlet 110 to an external air source (e.g., outside of the building) and an interior space of the building (e.g., a basement or utilities closet) occupied by the water heater 100. The controller can actuate the air supply valve 122 to maintain air temperatures above a minimum heat pump 120 operation threshold (e.g., 65° Fahrenheit) to preserve heat pump 120 efficiency and reduce reliance on resistive heating elements.

In this variation, the controller can detect a first air temperature of air proximal the water heater 100 (i.e., ambient air surrounding the water heater 100) based on a first signal output by a first air temperature sensor 114. In response to the first air temperature exceeding the minimum heat pump operating temperature (e.g., 65° Fahrenheit), the controller can: trigger the air supply valve 122 to couple the air inlet 110 to the interior space of the building to supply air from the interior space of the building to the heat pump 120; and activate the heat pump 120 to transfer thermal energy from air supplied to the heat pump 120 from a space proximal the water heater 100 to water stored in the water tank 108.

Alternatively, in response to the first air temperature falling below the minimum heat pump operating temperature, the controller can: trigger the air supply valve 122 to couple the air inlet 110 to an external air supply; trigger a blower 178, arranged within the water heater 100, to draw air to the water heater 100 from the external air supply; and detect a second air temperature of air entering the air inlet 110 from the external air supply based on a second signal output by a second temperature sensor 114. In response to the second air temperature exceeding the minimum heat pump operating temperature, the controller can: maintain the air inlet 110 coupled to the external air supply; and activate the heat pump 120 to transfer thermal energy from air supplied to the heat pump 120 from the external air supply to water stored in the water tank 108.

Alternatively, in response to the second air temperature remaining below the minimum heat pump operating temperature (i.e., indicating the external air supply and the air surrounding the water heater 100 lack sufficient thermal energy to operate the heat pump 120), the controller can: deactivate the heat pump 120; and trigger the set of resistive heaters 130 to heat water stored in the water tank 108 toward the target supply temperature.

In one example, the water heater 100 can: draw air to the heat pump 120 via an air supply pipe coupled to an external air supply outside of the building; detect a first air temperature of 40° Fahrenheit of air entering the air inlet 110 from the external air source; and, in response to the first air temperature falling below the minimum heat pump operating temperature of 65° Fahrenheit, trigger the air supply valve 122 to couple the air inlet 110 to the interior space of the building. The controller can then: detect a second air temperature of 72° Fahrenheit of air entering the air inlet 110 from the interior space of the building; and activate the heat pump 120 to heat water to the target supply temperature.

Accordingly, the water heater 100 can selectively draw air to the heat pump 120 from multiple air sources based on real-time air temperatures to maintain operation of the heat pump 120. Therefore, the controller can prioritize operation of the heat pump 120 when warm air is available from either the interior space or the external air supply, and default to resistive heating when these air sources lack sufficient thermal energy, thereby: extending the operational runtime of the heat pump 120; reducing energy consumption by resistive heating; and maintaining reliable hot water delivery across a range of ambient and environmental conditions (e.g., during operation in colder climates).

In one variation, the water heater 100 can be configured to dynamically expel cooled air (e.g., between 45° and 65° Fahrenheit), generated by the heat pump 120 during water heating cycles, to multiple air sources (e.g., an interior space of the building or an external air source). In this variation, the controller can selectively route the expelled air to augment or avoid affecting the temperature of a space proximal the water heater 100 based on an ambient air temperature of the space and a threshold air temperature (e.g., a preset value defined by a user). In particular, the water heater 100 can include an air return valve 124 configured to selectively couple the air outlet 112 to an external air source (e.g., outside of the building) and an interior space of the building (e.g., a basement or utilities closet) occupied by the water heater 100.

In this variation, the controller can detect a first air temperature of the interior space of the building based on a first signal output by an air temperature sensor 114; and, in response to the first air temperature exceeding the threshold air temperature, trigger the air return valve 124 to direct cooled air, generated by the heat pump 120 and exiting the air outlet 112, toward the interior space of the building. Alternatively, in response to the first air temperature falling below the threshold air temperature, the controller can trigger the air return valve 124 to couple the air outlet 112 to the external air source to direct cooled air, generated by the heat pump 120, toward the external air source. Accordingly, in response to an ambient air temperature of the interior space exceeding the threshold air temperature, the controller can trigger the air return valve 124 to direct cooled air to the interior space to reduce cooling load on adjacent HVAC systems. Alternatively, in response to the ambient air temperature falling below the threshold air temperature, the controller can trigger the air return valve 124 to direct cooled air externally to avoid undesired cooling of the interior space.

In one variation, the water heater 100 can be configured to cooperate with an HVAC system of the building to augment the supply of high and/or low-temperature air generated by the HVAC system. In one example, the air supply valve 122 can be configured to selectively couple the air inlet 110 to a return duct of the HVAC system (e.g., a warm-air return duct). In this example, the controller can detect a first air temperature of air in the HVAC return duct based on a first signal output by a first air temperature sensor 114. In response to the first air temperature exceeding the minimum heat pump operating temperature (e.g., 65° Fahrenheit), the controller can: trigger the air supply valve 122 to couple the air inlet 110 to the HVAC return duct; and activate the heat pump 120 to transfer thermal energy from air supplied to the heat pump 120 from the HVAC return duct to water stored in the water tank 108.

In another example, the air return valve 124 can be configured to selectively couple the air outlet 112 to a supply duct of the HVAC system (e.g., a cold air supply duct). In this example, the controller can detect a second air temperature of air within an interior space of the building based on a second signal output by a second air temperature sensor 114. In response to the second air temperature exceeding the threshold air temperature (e.g., 60° Fahrenheit), the controller can: trigger the air return valve 124 to couple the air outlet 112 to the HVAC supply duct; and direct cooled air, generated by the heat pump 120 during operation, into the HVAC system to augment cooling of the building. Therefore, the water heater 100 can cooperate with the HVAC system to: draw heated return air to the heat pump 120; and supply cooled air from the heat pump 120 to the HVAC supply duct during concurrent heating operation. Accordingly, the water heater 100 can reduce reliance on resistive heating, augment HVAC efficiency, and maintain integration of the water heating and air handling systems across a range of building conditions.

17. Leak Detection

In one variation, as shown in FIG. 13, Blocks of the method S100 recite, during a null hot water consumption window: triggering a shutoff valve 174, arranged upstream of the water tank 108, to close to interrupt flow of cold water from the building to the water tank 108 in Block S190; detecting a first water pressure within the building at a first time during the null hot water consumption window in Block S192; detecting a second water pressure within the building at a second time during the null hot water consumption window in Block S192; in response to the second water pressure falling below the first water pressure, interpreting a water leak within the building in Block S194; in response to interpreting the water leak, generating an alert indicating the water leak within the building in Block S196; and serving the alert to a user in Block S198. In this variation, the water heater 100 is configured to detect water leaks within the water heater 100 or at a downstream location within the building. In response to detecting a water leak within and/or outside of the water heater 100, the water heater 100 can interrupt the water supply to mitigate potential damage resulting from the water leak and/or alert a user to the water leak.

In one variation, the water heater 100 can detect a water leak within the building (i.e., downstream of the water heater 100) by interrupting the water supply and detecting a decay of water pressures within the water heater 100. In this variation, the water heater 100 can include: a shutoff valve 174 (e.g., an electromechanical shutoff valve 174) arranged within the housing 102 and interposed between the cold water inlet 104 and the water tank 108; and a pressure sensor 116 arranged downstream of the shutoff valve 174. The pressure sensor 116 can be configured to output signals representing water pressures in hot water supply lines within the building. In this variation, the controller can: trigger the shutoff valve 174 to a closed position to interrupt flow of water from the cold water supply to the water tank 108; and deactivate the heating elements (e.g., the heat pump 120 and the set of resistive heaters 130). In particular, the controller can isolate a water leak outside of the water heater 100 by deactivating the heating elements to prevent potential thermal expansion resulting from heating and cooling water within the water heater 100. In one example, the water heater 100 can: implement methods and techniques described below to predict a null hot water consumption window (i.e., a time period of zero water consumption); and trigger the shutoff valve 174 to the closed position and deactivate the heating elements during the null hot water consumption window.

The controller can then: access a set of signals output by the pressure sensor 116 and representing water pressures in hot water supply lines within the building the shutoff valve 174 in the closed position; and interpret a water leak, within the building and downstream of the water heater 100, based on a decay of water pressures represented in the set of signals. In particular, the controller can: detect a first water pressure within the building at a first time with the shutoff valve 174 in the closed position; detect a second water pressure within the building at a second time with the shutoff valve 174 in the closed position; and, in response to the second water pressure falling below the first water pressure, interpret a water leak within the building. In response to interpreting the water leak, the controller can maintain the shutoff valve 174 in the closed position. Additionally, the controller can: generate an alert indicating a water leak within the building; and serve the alert to the user (e.g., via a user interface).

In one variation, the water heater 100 can be configured to detect a water leak within the water heater 100 based on presence of water proximal a base of the housing 102. In particular, in this variation, the water heater 100 can include: a drip pan arranged within the housing 102 and configured to receive water (e.g., due to internal component failure, condensation, or rupture of internal plumbing connections within the water heater 100); and a moisture sensor 118 configured to detect water (or “moisture”) within the drip pan.

In this variation, the controller can: access a signal output by the moisture sensor 118; in response to the signal indicating presence of water within the drip pan, activate the shutoff valve 174 (e.g., the electromechanical shutoff valve 174) to interrupt the water supply; generate an alert indicating a water leak within the water heater 100; and serve the alert to the user (e.g., via a user interface). Accordingly, the water heater 100 can: detect water leaks within the water heater 100 and/or the building (i.e., downstream of the water heater 100); and mitigate potential damage resulting from the water leak by alerting a user to the water leak and/or interrupting the water supply.

In another variation, the water heater 100 can be configured to detect and alert a user to abnormal fluctuations in the water supply pressure of the building. In this variation, the water heater 100 can include a pressure sensor 116 arranged upstream of the water tank 108 and configured to output signals representing water pressures within the cold water supply line. The controller can monitor the set of signals output by the pressure sensor 116 and, in response to detecting a pressure value exceeding or falling below a threshold water pressure range, serve an alert to the user (e.g., via a user interface). For example, the controller can interpret a water pressure exceeding 100 psi as indicative of a high-pressure condition. Alternatively, the controller can interpret a water pressure below 30 psi as indicative of a low-pressure condition. Therefore, the water heater 100 can detect fluctuations in the incoming water supply pressure and alert the user to mitigate potential damage resulting from excessively high or low water pressure.

18. Selective Component Activation

In one variation, the water heater 100 can be configured to selectively operate heating elements based on the current rating of the available power input. In particular, the water heater 100 can receive power at a constant supply voltage and can be installed on circuits rated for different amperages. For example, in a nominal mode, the water heater 100 can be connected to a 30 ampere circuit and operate all heating elements (e.g., the heat pump 120, the inline heater 140, the set of resistive heaters 150). Alternatively, in a limp mode, the water heater 100 can be connected to a 7.5 ampere circuit, during which heating elements that require high power input are physically and electrically disabled.

In this variation, the water heater 100 can include a removable jumper in the power circuit that—when removed—electrically disconnects all high-power heating elements (e.g., the inline heater 140, the set of resistive heaters 150) from the power supply while maintaining power to the heat pump 120 and the controller. Additionally, the water heater 100 can include a control jumper arranged within the control circuitry. The control jumper can be installed or removed to indicate to the controller whether the water heater 100 is operating in limp mode or nominal mode. Accordingly, the controller can detect a configuration corresponding to limp mode based on presence or absence of the control jumper and selectively disable heater activation functions in software. Thus, the removable jumper prevents current flow to the heating elements (e.g., even if activation is attempted), and the control jumper prevents activation attempts by indicating the hardware configuration to the controller.

18.1 Power Junctions

In one variation, the water heater 100 can be configured to selectively activate and disable components (e.g., the inline heater 140, the recirculation pump 160) based on available power input. In particular, the water heater 100 can disable high-power components (e.g., the inline heater 140) when limited to a lower-power supply and enable these components when coupled to a higher-power supply. In this variation, the water heater 100 can include a first power junction 180: configured to couple to a first power supply at a first power and supply power to the heat pump 120; and electrically isolated from the inline heater 140. The water heater 100 can further include a second power junction 180 configured to: couple to a second power supply at a second power greater than the first power; and supply power to the heat pump 120 and the inline heater 140. In this variation, the controller can disable the inline heater 140 when power is supplied to the first power junction 180. Alternatively, the controller can activate the inline heater 140 when power is supplied to the second power junction 180.

18.2 Inline Power Supply Transformer

In one variation, the water heater 100 can include a power cable configured to connect to an electrical outlet, the power cable including: an electromechanical interface at a plug interface configured to connect to the electrical outlet and detect a voltage from the power supply; and an inline transformer configured to convert a low power supply (e.g., 120 volts and 15 amperes) to a high power supply (e.g., 240 volts and 7.5 amperes). For example, the electromechanical interface can include relays, automatic transfer switches, manual disconnect switches, motorized valves, and/or solenoid valves.

In one example, the electromechanical interface can include: a set of relays initially configured in an “on” position, wherein current is supplied to the set of components of the water heater 100 from the power source; and an inverter configured to, when the power cable is coupled to a low power supply, transform a portion of an incoming AC current from the power supply into DC current and actuate the set of relays to an “off” position.

In this variation, when the power cable is coupled to a low power supply, the water heater 100 can activate the inline transformer to transform the low power supply to the high power supply. Additionally, when the power cable is coupled to a low power supply, the water heater 100 can: selectively disable components, such as the inline heater 140 and/or the recirculation pump 160; and/or implement a maximum temperature for heating water stored in the water tank 108. In particular, the water heater 100 can selectively disable select components, via the electromechanical interface, to reduce the overall power demand and prevent potential overloads or damage to the power supply.

In one example, the power cable includes: a passive inline transformer configured to supply the water heater 100 with a 240 volts alternating current (or “VAC”) power supply at up to 7.5 amperes (or “A”) from a standard 120 VAC, 15A outlet; and an electromechanical plug configured to interface with an instance of the water heater 100. In particular, in this example, the electromechanical plug can supply 240 VAC to a control board of the water heater 100 and the heat pump 120. Furthermore, the electromechanical plug (or alternatively a secondary electromechanical bus bar), is configured to isolate the 240 VAC from the resistive heating elements. For example, the electromechanical plug can omit a non-switched line connection to the set of resistive heating elements, thereby electrically isolating these components from the low-power supply.

In this variation, when the power cable is coupled to a low-power source (e.g., a 120 VAC, 15A circuit), the electromechanical plug can restrict activation of high-power components by disabling the inline heater 140, the set of resistive heaters 130, and the recirculation pump 160, such that the water heater 100 heats water via the heat pump 120 only. Then, once full electrical service is established (e.g., a 240 VAC, 30A connection), a second power line can be reconnected to the non-switched side of the resistive heating elements, via the electromechanical plug or the secondary bus bar, to restore functionality to the previously disabled components. Additionally or alternatively, the low-power electromechanical plug can transmit a signal to the control board, indicating a limited power configuration.

In another variation, in response to failure of an existing water heater 100 (e.g., a gas water heater 100 located within a home), a homeowner can install an instance of the water heater 100 as a replacement. In this variation, upon coupling the power cable to an available electrical outlet, the water heater 100 can detect the power supply configuration via the electromechanical interface. In response to detecting a low-power supply (e.g., 120 VAC, 15A) and absence of a high-power connection adjacent the water heater 100, the controller can: activate the inline transformer to convert the low-power supply to a 240 VAC output for operation of the heat pump 120; and deactivate the set of resistive heaters 130 to avoid excessive current draw. The water heater 100 can then maintain a limited-power operating mode (i.e., heating water via the heat pump 120 only) until a dedicated high-power supply (e.g., 240 VAC, 30A) is installed. Upon detecting availability of the high-power supply, the controller can: restore power to the set of resistive heaters 130; and lift any associated maximum temperature restrictions that were imposed during low-power operation. Therefore, the water heater 100 can be configured to operate temporarily in a low-power mode, such as during emergency replacement of a failed unit, while maintaining essential heating functionality and protecting internal components from electrical overload.

19. Water Consumption Forecast

Blocks of the method S100 recite: predicting a first estimated time until a first hot water consumption event within a building in Block S102; and predicting a second estimated time until a second null hot water consumption window (i.e., a time period) within the building in Block S104. Generally, during a calibration period, the water heater 100 can: monitor water consumption data (e.g., a set of flow rates) representing hot water consumption within a building; and derive a water consumption forecast for the building based on this water consumption data. In particular, the water consumption forecast represents predicted water consumption (e.g., flow rates, volumes of water consumed) within the building at particular times and/or time periods (or “hot water consumption events”). For example, the water heater 100 can derive a water consumption forecast representing an average hot water consumption volume during a hot water consumption event based on water consumption patterns observed on the same day across multiple weeks, all days of the week, specific subsets of days, seasonal variations, differences between weekdays and weekends, and weather conditions (e.g., rainy days or temperature fluctuations). For example, the water heater 100 can monitor water consumption data over a 30-day calibration period preceding implementation of the water consumption forecast to detect typical water consumption patterns and variations within the building.

The water heater 100 can then, during operation, heat water within the water tank 108 according to the water consumption forecast to maintain a supply of hot water prior to each predicted hot water consumption event. Therefore, the water heater 100 can derive a customized water consumption forecast during the calibration period that informs water heating actions during the operation period. By heating water according to the water consumption forecast, the water heater 100 reduces inefficient, unnecessary heating operations, such as maintaining elevated tank temperatures during extended periods of inactivity and synchronizes heating cycles with predicted water demand to reduce perceived latency and preserve user comfort at the point of use.

19.1 Consumption Prediction Based on Flow Rate Data

In one variation, as shown in FIGS. 14 and 15, Blocks of the method S100 recite: accessing a set of historical flow rate data representing flow rates of water from the water heater 100 to the building in Block S180; calculating an average hot water consumption volume during historical time windows coinciding with a hot water consumption event based on the set of historical flow rate data in Block S182; in response to the average hot water consumption volume exceeding a threshold volume, predicting the hot water consumption event in Block S102; and setting a buffer duration preceding the hot water consumption event based on variance in start times of hot water consumption events during historical time windows coinciding with the first hot water consumption event in Block S184.

In one variation, the water heater 100 can: access a set of historical flow rate data recorded by a flow rate sensor 128 (e.g., arranged proximal the cold water inlet 104 of the water tank 108) and representing flow rates of water from the water heater 100 to the building; and predict hot water consumption events based on fluctuations (i.e., spikes and/or drops) in flow rate. In this variation, the water heater 100 can: calculate an average hot water consumption volume during historical time windows coinciding with a time window of the hot water consumption event based on the set of historical flow rate data; and predict the hot water consumption event based on the average hot water consumption volume. For example, the water heater 100 can predict the hot water consumption event in response to the average hot water consumption volume exceeding a threshold volume (e.g., one gallon). Furthermore, the water heater 100 can estimate a buffer duration (e.g., fifteen minutes) preceding the hot water consumption event based on the set of historical flow rate data.

In one example, for a particular time window (e.g., between 6:00 AM and 6:30 AM on Wednesday), the water heater 100 can: access a set of flow rate data recorded during the time window over a particular interval (e.g., 30 days); calculate the average hot water consumption volume during instances of the time window over the interval based on the set of flow rate data; and predict a hot water consumption event during the time window based on the average hot water consumption volume exceeding a threshold volume of one gallon. The water heater 100 can then store the average hot water consumption volume in association with the hot water consumption event in the water consumption forecast for the building. The water heater 100 can then repeat this process for each hot water consumption event identified in the set of flow rate data to derive a comprehensive water consumption forecast for the building.

19.1.1 Predicted Water Consumption Volumes

In one variation, the water heater 100 can predict an average hot water consumption volume during a hot water consumption event. For example, for a hot water consumption event on a first day (e.g., Monday), the water heater 100 can predict the average hot water consumption volume based on water consumption patterns during historical time windows coinciding with the hot water consumption event across multiple occurrences of the first day. In one example, for a hot water consumption event between 7:00 AM and 8:00 AM on a Wednesday, the water heater 100 can: access a set of flow rate data recorded between 7:00 AM and 8:00 AM over the previous seven Wednesdays; and calculate the average hot water consumption volume between 7:00 AM and 8:00 AM based on the set of flow rate data.

In another variation, the water heater 100 can predict the average hot water consumption volume during the hot water consumption event based on water consumption patterns during historical time windows coinciding with the hot water consumption event across all days and/or a subset of days of the week. For example, for a hot water consumption event between 6:00 PM and 6:15 PM on a Saturday, the water heater 100 can: access a set of flow rate data recorded between 6:00 PM and 6:15 PM over the previous five Saturdays and Sundays; and calculate the average hot water consumption volume between 6:00 PM and 6:15 PM based on the set of flow rate data.

In another variation, the water heater 100 can predict the average hot water consumption volume by applying weighted factors to particular days of the week. For example, for a hot water consumption event between 5:00 PM and 5:30 PM on a Wednesday, the water heater 100 can: access a first set of flow rate data recorded between 5:00 PM and 5:30 PM over the previous five Mondays; access a second set of flow rate data recorded between 5:00 PM and 5:30 PM over the previous five Tuesdays; assign a first weight to the first set of flow rate data; assign a second weight, greater than the first weight, to the second set of flow rate data (i.e., reflecting the higher relevance of water consumption on days preceding the Wednesday, such as Tuesdays); and calculate the average hot water consumption volume between 5:00 PM and 5:30 PM based on the first weight assigned to the first set of flow rate data and the second weight assigned to the second set of flow rate data (i.e., a weighted average of water consumption over the previous five Mondays and Tuesdays).

In another variation, the water heater 100 can predict the average hot water consumption volume during the hot water consumption event by applying weighted factors based on historical conditions, such as weather conditions (e.g., water consumption on days exhibiting a similar temperature to the first day) and/or seasonal conditions (e.g., water consumption during the summer). For example, for a hot water consumption event between 2:00 PM and 2:30 PM on a Saturday with a forecast ambient temperature (e.g., 20° Fahrenheit) below a threshold temperature (e.g., 30° Fahrenheit), the water heater 100 can: access a first set of flow rate data recorded between 2:00 PM and 2:30 PM over the previous five Saturdays with similar low ambient temperatures (e.g., between 5° to 30° Fahrenheit); access a second set of flow rate data recorded between 2:00 PM and 2:30 PM over the previous five Saturdays with moderate ambient temperatures slightly above the threshold (e.g., between 30° to 40° Fahrenheit); assign a first weight to the first set of flow rate data (i.e., reflecting the higher relevance of water consumption on days with low ambient temperatures); assign a second weight, lower than the first weight, to the second set of flow rate data (i.e., reflecting the lesser influence of moderately cool days on water consumption patterns); and calculate the average hot water consumption volume between 2:00 PM and 2:30 PM on the forecast low-temperature Saturday based on the first weight assigned to the first set of flow rate data and the second weight assigned to the second set of flow rate data (i.e., a weighted average of water consumption on Saturdays with low and moderate ambient temperatures).

Therefore, the water heater 100 can derive an accurate water consumption forecast for the building based on water consumption patterns across different time periods, days of the week, and/or historical conditions (e.g., weather and seasonal variations): to improve water consumption predictions, such as for specific days and temperature conditions; and to increase energy efficiency by aligning heating cycles with actual hot water demand of the building.

19.2 Consumption Prediction Based on Historical Consumption Patterns

In one variation, Blocks of the method S100 recite: accessing a set of historical flow rate data representing flow rates of water from the water heater 100 to the building in Block S180; generating a set of demand templates based on the set of historical flow rate data, each demand template representing water consumption within the building during a time window in Block S186; accessing a set of current flow rate data representing flow rates of water from the water heater 100 to the building during a current time window preceding the hot water consumption event in Block S114; selecting a first demand template, in the set of demand templates in Block S188; and predicting a hot water consumption event based on the demand template representing water consumption coinciding with the hot water consumption event in Block S102.

In this variation, the water heater 100 can implement methods and techniques described above to: access historical flow rate data representing water supplied to the building; and segment the historical flow rate data into a set of demand templates, each demand template representing a historical time window (e.g., from midnight to midnight). For example, each demand template can: represent a water consumption pattern during a historical time window; and include a first duration (e.g., 12 hours) for matching with current water consumption data and a second duration (e.g., 4 hours) for predicting future water consumption.

The water heater 100 can then: access a first set of current flow rate data representing water consumption within the building during a current time window (e.g., the past 12 hours); match the first set of current flow rate data to a first duration within a demand template based on similarity in consumption pattern; and predict future water consumption based on a second duration in the demand template. In particular, the water heater 100 can select a first demand template, in the set of demand templates: representing a first set of historical flow rate data corresponding to the first set of current flow rate data; and representing a historical time window corresponding to the current time window. The water heater 100 can then predict a hot water consumption event based on the first demand template representing future water consumption.

19.3 Consumption Event Prediction Responsive to Plan Deviations

In one variation, as shown in FIG. 8, the water heater 100 can temporarily modify the water consumption forecast in response to detection of deviations from the expected hot water consumption schedule. In particular, the water heater 100 can anticipate additional deviations from predicted water consumption events following a detected deviation (e.g., a user showering at an unexpected time) and modify future forecasts to reflect the likelihood of repeat behavior.

In this variation, the water heater 100 can implement methods and techniques described above: to predict a null hot water consumption window; and to detect flow of water from the water heater 100 during the null hot water consumption window (i.e., unexpected water consumption). The water heater 100 can then generate a prediction for a new hot water consumption event within the building based on detection of flow of water from the water heater 100 during the null hot water consumption window. More specifically, in response to detecting flow during the null hot water consumption window, the water heater 100 can temporarily override the water consumption forecast by predicting a new hot water consumption event (e.g., at a similar time on subsequent days).

For example, the water heater 100 can: predict a null hot water consumption window between 2:00 PM and 4:00 PM; and detect 15 gallons of hot water consumption between 2:00 PM and 4:00 PM (e.g., corresponding to a midday shower). The water heater 100 can then: interpret the deviation as indicative of a new short-term pattern; schedule preheating or recirculation activity preceding the same window on subsequent days; and monitor for repetition of similar water consumption patterns to retain or discard the hot new water consumption event. Therefore, the water heater 100 can adjust the water consumption forecast based on detection of deviations from expected water consumption patterns and preemptively adapt future heating and recirculation schedules in anticipation of recurring off-pattern behavior.

19.4 Consumption Event Prediction Based on User Inputs

In one variation, during installation of an instance of the water heater 100 in a building, the water heater 100 can: prompt the user to specify information about the user(s) and/or the building; and refine and/or derive the water consumption forecast based on the user input(s). For example, the water heater 100 can prompt the user to specify: a quantity of users (e.g., two adults and one child) served by the instance of the water heater 100; a primary function (e.g., serving a single-family home, a commercial office, or a vacation home) of the instance of the water heater 100; a set of known water consumption patterns or user routines (e.g., two adults shower each morning at 6:00 AM); a quantity and/or type of fixtures (e.g., shower heads, bathroom faucets) arranged throughout the building; a location of each fixture in the building (e.g., a shower head located in a first-floor bathroom); and/or a location (e.g., a basement, an outdoor utility closet) of the instance of the water heater 100 in the building. The water heater 100 can then leverage these user inputs to refine and/or derive the water consumption forecast in conjunction 180 with the water consumption data recorded during the calibration period. For example, the water heater 100 can refine and/or calculate expected hot water consumption volumes during hot water consumption events and/or predict hot water consumption events.

In one example, the water heater 100 can receive selection of: a quantity of four adult users served by an instance of the water heater 100; and serving a single-family home as a primary function of the water heater 100. The water heater 100 can then: predict a quantity of three showers to occur during a hot water consumption event between 6:00 AM and 6:30 AM each weekday (i.e., Monday-Friday); calculate an expected consumption volume of 100 gallons to be consumed between 6:00 AM and 6:30 AM each weekday based on the quantity of three showers; and store the expected volume of 100 gallons, in association with the hot water consumption event between 6:00 AM and 6:30 AM, in the water consumption forecast. The water heater 100 can then, during the calibration period: access a set of flow rate data representing flow rates between 6:00 AM and 6:30 AM each weekday over a 30-day interval; and calculate an average consumption volume of 50 gallons between 6:00 AM and 6:30 AM each weekday based on the set of flow rate data. The water heater 100 can then update the hot water consumption event with the expected consumption volume of 50 gallons between 6:00 AM and 6:30 AM each weekday. Accordingly, the water heater 100 can leverage context-specific user inputs (e.g., quantity of users, known routines, fixture types) in conjunction 180 with actual water consumption data to refine the water consumption forecast to represent both predicted and actual water consumption patterns.

20. Water Heating Schedule+Heating Element Selection

Blocks of the method S100 recite: predicting an estimated time until a hot water consumption event within a building in Block S102; accessing a water temperature of water stored in the water tank 108 of the water heater 100 supplying hot water to the building in Block S110; accessing an air temperature of air supplied to the heat pump 120 in Block S112; accessing a target supply temperature for water supplied to the building by the water heater 100 in Block S106; estimating a heating duration to heat water stored in the water tank 108 to the target supply temperature based on a difference between the water temperature and the target supply temperature in Block S118; in response to the estimated duration approaching the heating duration, triggering a heating element, arranged within the water heater 100, to heat water stored in the water tank 108 toward the target supply temperature in Block S120; and, at the water heater 100, supplying hot water, proximal the target supply temperature and stored in the water tank 108, to the building during the hot water consumption event in Block S170.

Generally, the water heater 100 can heat water according to the water consumption forecast to maintain hot water availability within the building preceding each hot water consumption event, as shown in FIGS. 8-10 and 16. In one implementation, the water heater 100 can: predict an estimated time until a hot water consumption event within the building; access a water temperature of water stored in the water tank 108; and estimate a heating duration to heat water stored in the water tank 108 to the target supply temperature based on a difference between the water temperature and the target supply temperature. Then, in response to the estimated duration approaching the heating duration, the water heater 100 can trigger a heating element (e.g., the heat pump 120 and/or the set of resistive heaters 130) to heat water stored in the water tank 108 toward the target supply temperature. The water heater 100 can then supply hot water, proximal the target supply temperature and stored in the water tank 108, to the building during the hot water consumption event.

Furthermore, in this variation, the water heater 100 can activate the heat pump 120 and/or the set of resistive heaters 130 to pre-heat water based on ambient air conditions proximal the water heater 100. In particular, the water heater 100 can implement methods and techniques described above to: detect an air temperature of air entering the air inlet 110 (or air proximal the water heater 100); and, in response to the air temperature exceeding the minimum heat pump operating temperature, estimate the heating duration to heat water stored in the water tank 108 to the target supply temperature via the heat pump 120. More specifically, the water heater 100 can estimate the heating duration based on a function relating: a difference between the water temperature (i.e., the current temperature of water in the water tank 108) and the target supply temperature; a total volume of the water tank 108; and the air temperature.

Alternatively, the water heater 100 can implement the set of resistive heaters 130 to pre-heat water stored in the water tank 108 when ambient conditions prevent operation of the heat pump 120. In particular, the water heater 100 can implement methods and techniques described above: to detect an air temperature of air entering the air inlet 110 (or air proximal the water heater 100); and, in response to the air temperature falling below the minimum heat pump operating temperature, estimate the heating duration to heat water stored in the water tank 108 to the target supply temperature via the set of resistive heaters 130. Therefore, the water heater 100 can prioritize operation of the heat pump 120 (i.e., to efficiently heat water), while maintaining reliable heating performance across a range of ambient conditions.

21. Pre-Heating Water to Target Holding Temperature

Blocks of the method S100 recite: accessing a target holding temperature, exceeding the target supply temperature, for maintaining water stored within the water tank 108 in Block S108; estimating a heating duration to heat water stored in the water tank 108 to the target holding temperature based on a difference between the water temperature and the target holding temperature in Block S118; in response to the estimated duration approaching the heating duration, triggering a heating element, arranged within the water heater 100, to heat water stored in the water tank 108 toward the target holding temperature in Block S120; and, at the mixing valve 150, in response to flow of water from the water heater 100 during the hot water consumption event, combining cold water with hot water, exiting the water tank 108 proximal the target holding temperature, to cool water to the target supply temperature in Block S170.

In one implementation, the water heater 100 can: pre-heat water stored in the water tank 108 to a target holding temperature (e.g., between 140° and 160° Fahrenheit) that exceeds the target supply temperature; and, via the mixing valve 150, reduce an outlet temperature of water supplied to the building to the target supply temperature. In this implementation, the water heater 100 can implement methods and techniques described above to: predict a hot water consumption event within the building; and access a water temperature of water stored in the water tank 108. The water heater 100 can then estimate a heating duration to heat water stored in the water tank 108 to the target holding temperature based on a difference between the water temperature and the target holding temperature. In response to the estimated duration approaching the heating duration, the water heater 100 can then trigger a heating element (e.g., the heat pump 120 and/or the set of resistive heaters 130) to heat water stored in the water tank 108 toward the target holding temperature. Then, in response to flow of water from the water heater 100 during the hot water consumption event, the mixing valve 150 can combine cold water with hot water, exiting the water tank 108 proximal the target holding temperature, to cool water to the target supply temperature.

In another variation, the water heater 100 can: predict a hot water consumption event within the building; and predict a hot water consumption volume during the hot water consumption event that exceeds a total volume of the water tank 108. In response to predicting the hot water consumption volume exceeding the total volume of the water tank 108, the water heater 100 can set the target holding temperature exceeding the target supply temperature proportional a volume difference between the total volume of the water tank and the predicted hot water consumption volume. Then, during the hot water consumption event, in response to flow of water from the water heater 100, the mixing valve 150 can combine cold water with hot water, exiting the inline heater 140 proximal the maximum water temperature, to cool water to the target supply temperature.

By preheating water to the target holding temperature exceeding the target supply temperature and regulating the outlet temperature via the mixing valve 150, the water heater 100 can extend the effective volume of hot water stored within the water tank 108. More specifically, by maintaining water at a higher temperature within the water tank 108, the water heater 100 can mix a greater volume of cold water at the outlet to achieve the target supply temperature, thereby increasing the amount of deliverable hot water per unit volume stored. Therefore, the water heater 100 can increase hot water capacity, such as during high-demand periods, while maintaining consistent outlet temperature of water supplied to the building.

21.1 Variation: Time-Based Minimum Storage Temperature

In one variation, Block S126 of the method S100 recites calculating a minimum water temperature for water stored in the water tank 108. In this variation, the water heater 100 can dynamically calculate a minimum storage temperature for maintaining water in the water tank 108 based on time remaining before a predicted hot water consumption event, such that sufficient thermal energy is available for heating within the heating duration. In this variation, the water heater 100 can: access a hot water consumption volume associated with a hot water consumption event; access an air temperature of air supplied to the heat pump 120; and estimate a fixed target heating duration to heat water stored in the water tank 108. The water heater 100 can then calculate a minimum water temperature for water stored in the water tank 108 based on a function relating: the fixed target heating duration; the target supply temperature (or the target holding temperature); the total tank volume; and the air temperature.

Then, during an initial time period preceding the heating duration, the water heater 100 can trigger the heat pump 120 to maintain water proximal the minimum water temperature. In particular, the water heater 100 can dynamically maintain water proximal the minimum water temperature, such that the water heater 100 maintains capacity to heat water to the target supply temperature prior to the hot water consumption event. Thus, in this variation, the water heater 100 maintains sufficient thermal potential in advance of forecasted heating intervals, thereby reducing reliance on high-power heating modes (e.g., combined resistive and heat pump 120 operation) and preserving energy efficiency while meeting predicted hot water demand.

22. Variation: Excess Energy Heating Periods

In one variation, Blocks of the method S100 recite: accessing a set of forecast electrical grid metrics representing forecast energy supply within an electrical grid supplying electrical energy to the water heater 100 in Block S136; identifying a time window of excess energy supply preceding a hot water consumption event and represented in the set of forecast electrical grid metrics in Block S138; and scheduling activation of a heating element during a heating duration intersecting the time window to heat water stored in the water tank 108 to the target holding temperature.

In this variation, the water heater 100 can selectively heat water stored in the water tank 108—further in advance of predicted hot water consumption events—when an excess supply of energy is available from the electrical grid. In this variation, the water heater 100 can: implement methods and techniques described above to predict an upcoming hot water consumption event, a hot water consumption volume, and a start time of the hot water consumption event; access a set of forecast electrical grid metrics (e.g., published by an electrical grid management database) representing forecast energy supply within an electrical grid supplying electrical energy to the water heater 100; identify a time wind between a current time and the start time that intersects a period of forecast excess energy supply on the electrical grid; and schedule activation of one or more heating elements to heat water during the time window. In one example, the water heater 100 can: identify a time window of excess energy supply preceding a hot water consumption event and represented in the set of forecast electrical grid metrics; and schedule activation of the heat pump 120 and the set of resistive heaters 130, during a heating duration intersecting the time window, to heat water stored in the water tank 108 to the target holding temperature. Accordingly, the water heater 100 can preemptively heat water stored in the water tank 108, prior to the upcoming hot water consumption event, when excess energy is available on the electrical grid. Thus, the water heater 100 can function as a thermal battery by storing excess electrical energy available on the electrical grid as heat within water stored in the water tank 108.

Furthermore, in this variation, the water heater 100 can: estimate a temperature drop of water stored in the water tank 108 between the time window and the event start time (e.g., based on a heat loss physics model stored in local memory in the controller); calculate a target holding temperature for water stored in the water tank 108 based on the temperature drop and the target supply temperature; and schedule activation of the heat pump 120 to heat water stored in the water tank 108 to the target holding temperature during the time window.

For example, the water heater 100 can: predict a hot water consumption event between 6:00 AM and 6:30 AM and associated with an expected hot water consumption volume of 25 gallons (e.g., for a single shower); identify a time window between 1:00 AM and 3:00 AM that intersects a period of forecast excess energy supply on the electrical grid; calculate a target holding temperature 160° Fahrenheit (i.e., to maintain at or above the target supply temperature of 120° F. by 6:00 AM); and schedule activation of the heat pump 120 at 1:00 AM (i.e., within the forecast excess energy supply period) to heat water stored in the water tank 108 to 160° Fahrenheit.

In this example, the water heater 100 can reschedule activation of the heat pump 120 at 1:00 AM from an original start time at 5:00 AM (e.g., previously defined in the water heating schedule) to align the water heating cycle with the period of forecast excess energy supply (e.g., a time period associated with low energy demand in the electrical grid). Furthermore, in this example, the water heater 100 can heat water during the period of forecast excess energy supply to reduce energy costs associated with heating the water, while maintaining water stored in the water tank 108 at or above the target supply temperature prior to the start time of the hot water consumption event at 6:00 AM.

In another variation, the water heater 100 can: access real-time building energy metrics; and selectively activate heating elements to heat water stored in the water tank 108 when a surplus of energy is available within the building, such as during periods of excess on-site generation or reduced internal power consumption. In this variation, the water heater 100 can: implement methods and techniques described above to predict a hot water consumption event within the building; and access a current energy supply and a current energy demand within the building. For example, the water heater 100 can cooperate with a building energy management system (e.g., a smart home hub) representing the current net power balance, such as a surplus from on-site solar generation or reduced building consumption. In response to the current energy supply exceeding the current energy demand within the building, the water heater 100 can: estimate a target water temperature, exceeding the target supply temperature, predicted to thermally decay to the target supply temperature by a start time of the hot water consumption event; and trigger the heat pump 120 and/or the set of resistive heaters 130 to heat water stored in the water tank 108 to the target water temperature. Therefore, the water heater 100 can opportunistically store excess on-site energy as thermal energy by heating water (e.g., in anticipation of upcoming demand).

Therefore, the water heater 100 can leverage electrical grid metrics to heat water (or schedule water heating) during time periods with a forecast excess supply of energy. The water heater 100 can thus: function as a thermal battery that stores excess energy available on the electrical grid in the form of hot water; and reduce energy consumption during periods of low energy supply or demand-matched energy supply from the electrical grid, thereby reducing a burden of water heating on the electrical grid.

23. Variation: Clean Energy Heating Periods

In one variation, the water heater 100 can selectively heat water stored in the water tank 108—further in advance of predicted hot water consumption events—when “clean” electricity is available on the electrical grid. In particular, in this variation, the water heater 100 can: implement methods and techniques described above to predict an upcoming hot water consumption event; access a set of forecast electrical grid metrics representing forecast time periods of clean energy supply available on the electrical grid; identify a time window prior to the hot water consumption event that intersects a period of forecast clean energy supply on the electrical grid; and schedule activation of the heat pump 120 during the time window. Accordingly, the water heater 100 can preemptively heat water, prior to the upcoming hot water consumption event, when clean energy is available on the electrical grid.

In one example, the water heater 100 can: predict a hot water consumption event between 7:00 PM and 7:30 PM and associated with an expected hot water consumption volume of 25 gallons (e.g., for a single washing machine cycle); identify a time window between 12:00 PM and 5:00 PM that intersects a period of forecast clean energy supply on the electrical grid; calculate a target holding temperature 160° Fahrenheit (i.e., to maintain the water at or above the target supply temperature of 120° F. by 7:00 PM); and schedule activation of the heat pump 120 at 3:00 PM (i.e., within the forecast clean energy supply period) to heat water stored in the water tank 108 to 160° Fahrenheit.

In this example, the water heater 100 can reschedule activation of the heat pump 120 at 3:00 PM from an original start time at 6:00 PM (e.g., previously defined in the water heating schedule) to align the water heating cycle with the forecast clean energy period, such as a time period when solar energy is available in the electrical grid. Furthermore, in this example, the water heater 100 can complete heating water by 5:00 PM to increase the proportion of solar energy consumed by the water heater 100 to heat water, while maintaining water at or above the target supply temperature immediately prior to the hot water consumption event commencing at 7:00 PM.

Accordingly, the water heater 100 can leverage electrical grid metrics to schedule water heating during time periods with a forecast supply of clean energy. Therefore, the water heater 100 can: function as a thermal battery that stores clean energy available on the electrical grid in the form of hot water; and increase the proportion of clean energy consumed by the water heater 100 to heat water (e.g., relative to non-renewable energy sources), thereby reducing the load imposed by water heating on the electrical grid (e.g., during peak demand intervals).

24. Variation: Water Heating Schedule Based on Cost Efficiency

In another variation, the water heater 100 can: access energy cost data such as a local energy guide representing cost-efficient time periods for heating water; and schedule activation of the heating elements during such cost-efficient time periods. For example, the water heater 100 can: access an address of the geographical location of the instance of the water heater 100; and access a local energy guide associated with the geographical location (e.g., based on a zip code identified in the address). In another example, the water heater 100 can receive an input from the user specifying an energy cost during a particular time window (e.g., identified in a utility bill). Additionally or alternatively, the water heater 100 can automatically activate the heating elements during cost-efficient time periods represented in the in the local energy guide.

In this variation, prior to a hot water consumption event in the building, the water heater 100 can: access a hot water consumption volume and a start time of the hot water consumption event; identify a cost-efficient period, preceding the start time, in the local energy guide; estimate a heating duration to heat water stored in the water tank to the target holding temperature (e.g., between 120° and 160° Fahrenheit) exceeding the target supply temperature (i.e., to account for thermal decay); and schedule activation of the heat pump 120 during the cost-efficient period and preceding the start time by at least the sum of the heating duration and a buffer period (e.g., fifteen minutes).

In one example, the water heater 100 can: predict a hot water consumption event between 6:00 AM and 6:30 AM and associated with an expected hot water consumption volume of 25 gallons (e.g., for a single shower); identify a cost-efficient period between 3:00 AM and 5:00 AM in the local energy guide; estimate a target holding temperature of 160° Fahrenheit predicted to thermally decay to the target supply temperature of 120° F. by 6:00 AM; estimate a heating duration of one hour to heat 30 gallons of water (i.e., including five gallons of extra water) to the elevated target holding temperature; and schedule activation of the heat pump 120 at 4:00 AM (i.e., within the cost-efficient period). Thus, the water heater 100 can heat water during cost-efficient periods to reduce energy costs associated with heating the water, while maintaining uninterrupted delivery of hot water during hot water consumption events.

25. Variation: Energy Efficient Heating Element Activation

In one variation, the water heater 100 can withhold preheating water prior to a forecasted hot water consumption event when the expected hot water consumption volume falls below a threshold volume (e.g., two gallons). In this variation, the water heater 100 can implement the inline heater 140 to rapidly heat water exiting the water tank 108 to the water temperature without requiring preheating of water stored in the water tank 108. For example, in response to predicting a hot water consumption event corresponding to a handwashing event (or other low-volume consumption event), the water heater 100 can withhold activation of the heat pump 120 and trigger the inline heater 140 to heat water exiting the water tank 108 during the handwashing event.

In this variation, the water heater 100 can: implement methods and techniques described above to predict a hot water consumption event within the building and a hot water consumption volume associated with the hot water consumption event; and, in response to the hot water consumption volume falling below the threshold volume, withhold activation of the heat pump 120. Then, during the hot water consumption event, in response to flow of water from the water heater 100, the water heater 100 can trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature. Thus, in this variation, the water heater 100 can conserve energy during low-volume hot water consumption events by implementing the inline heater 140 to rapidly heat relatively low volumes of water, thereby increasing energy efficiency without compromising hot water availability within the building.

In another variation, the water heater 100 can selectively activate heating elements based on the existing volume of hot water stored in the water tank 108. In this variation, prior to a hot water consumption event, the water heater 100 can: access a hot water consumption volume associated with the hot water consumption event; and detect a volume of water stored in the water tank 108 at or above the target supply temperature. In response to the hot water consumption volume falling below the volume of water stored in the water tank 108 at or above the target supply temperature (i.e., the current volume of available hot water), the water heater 100 can withhold activation of the heating elements. More specifically, water temperature may gradually decrease to the target supply temperature, such that an upper portion of the water tank 108 retains only the hot water consumption volume required for the hot water consumption event. Therefore, the water heater 100 can increase energy efficiency by minimizing unnecessary heating cycles and maintaining only the expected hot water consumption volume at or above the target supply temperature.

26. Scheduled Heat Pump Activation+Dynamic Heating Element Selection

In one variation, Blocks of the method S100 recite: prior to a hot water consumption event, triggering the set of resistive heaters 130 to heat water stored in the water tank 108 in Block S130; and at a start of the hot water consumption event, deactivating the set of resistive heaters 130 in Block S132. In this variation, the water heater 100 can: schedule activation of the heat pump 120 to heat water prior to a hot water consumption event (i.e., to prioritize activation of the heat pump 120); interpret viability of operating the heat pump 120 at a scheduled activation time based on real-time air temperatures and/or water temperatures; and reassign the scheduled heating operation from the heat pump 120 to the set of resistive heaters 130 in response to detecting insufficient thermal energy in the air supply.

In this variation, during a first time period, the water heater 100 can implement methods and techniques described above to: predict a hot water consumption event associated with a hot water consumption volume and a start time; and estimate a heating duration to heat water stored in the water tank (e.g., based on an estimated air temperature and water temperature). The water heater 100 can then schedule activation of the heat pump 120 at a heat pump activation time preceding the next instance of the hot water consumption event by at least the sum of the heating duration and a buffer period (e.g., fifteen minutes).

The water heater 100 can then, at the heat pump activation time during a second time period succeeding the first time period (e.g., the next day), detect an air temperature of air entering the air inlet 110 (i.e., air supplied to the heat pump 120). In response to the air temperature exceeding the minimum heat pump operating temperature, the water heater 100 can activate the heat pump 120 to heat water to the target supply temperature. Then, following the start time of the hot water consumption event, the water heater 100 can deactivate the heat pump 120.

Alternatively, in response to the air temperature falling below the minimum heat pump operating temperature, the water heater 100 can: detect a water temperature of water stored in the water tank 108; estimate a new heating duration to heat water stored in the water tank 108 from the water temperature to the target supply temperature via the set of resistive heaters 130 (e.g., an electric immersion heater) within the water tank 108 (i.e., rather than via the heat pump 120); and schedule activation of the set of resistive heaters 130 at a resistive heater activation time preceding the next instance of the hot water consumption event by at least the sum of the new heating duration and the buffer period.

Then, at the resistive heater activation time during a second time period succeeding the first time period, the water heater 100 can activate the set of resistive heaters 130 to heat water stored in the water tank 108. The water heater 100 can then, following the forecast start time, deactivate the set of resistive heaters 130. Thus, the water heater 100 can activate the set of resistive heaters 130 in absence of ambient thermal energy from the external air supply to prevent further cooling of the space adjacent to the water heater 100.

In one example, on a first day, the water heater 100 can: identify a hot water consumption event between 6:00 AM and 6:30 AM associated with a hot water consumption volume of 25 gallons; estimate a first heating duration of 45 minutes to heat 30 gallons (i.e., including five gallons of extra water) of water to the target supply temperature via the heat pump 120; and schedule activation of the heat pump 120 at 5:00 AM on a second day succeeding the first day (i.e., including a fifteen minute buffer). Then, at 5:15 AM on the second day (i.e., the heat pump activation time), the water heater 100 can: detect an air temperature of 72° Fahrenheit (i.e., of air entering the air inlet 110); and, in response to the air temperature exceeding the minimum heat pump operating temperature, trigger the heat pump 120 to heat water to the target supply temperature.

Alternatively, in the preceding example, in response to the air temperature falling below the minimum heat pump operating temperature, the water heater 100 can: estimate a second heating duration of 15 minutes to heat water stored in the water tank to the target supply temperature via the set of resistive heaters 130; and schedule activation of the set of resistive heaters 130 at 5:30 AM (i.e., including the fifteen minute buffer).

Accordingly, the water heater 100 can: initially schedule heating of water with sufficient time to operate the heat pump 120 (e.g., up to four times more efficient than resistive heating); implement the heat pump 120 if the temperature of air supplied to the heat pump 120 exceeds the heat pump 120 operation temperature (i.e., leveraging ambient thermal energy); and automatically schedule the activation of the set of resistive heaters 120 if the temperature of the external air supply falls below the heat pump 120 operation temperature (i.e., ambient thermal energy is insufficient to operate of the heat pump 120). Therefore, the water heater 100 can selectively activate heating elements based on the ambient conditions (i.e., air temperature) adjacent the water heater 100, to maximize energy efficiency while maintaining the ability to rapidly heat water (i.e., via the set of resistive heaters 130).

27. Dynamic Heating During Deviations from Water Consumption Plan

Blocks of the method S100 recite: predicting an estimated time until a null hot water consumption window within the building in Block S104; during the null hot water consumption window, triggering the heat pump 120 to maintain water stored in the water tank 108 proximal a nominal temperature less than the target supply temperature in Block S120; at the water heater 100, in response to flow of water from the water heater 100, triggering the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature in Block S140; deactivating the heat pump in Block S122; and deactivating the inline heater in Block S142.

In one implementation, the water heater 100 can: predict intervals characterized by an absence of expected hot water usage (or “null hot water consumption windows”); trigger the heat pump 120 to maintain a reduced nominal tank temperature during these intervals; and, in response to unexpected hot water demand, activate the inline heater 140 to rapidly heat water exiting the water tank 108 toward the target supply temperature. In this implementation, the water heater 100 can implement methods and techniques described above to predict a null hot water consumption window within the building. The water heater 100 can then, during the null hot water consumption window, trigger the heat pump 120 to maintain water stored in the water tank 108 proximal a nominal temperature less than the target supply temperature. In response to flow of water from the water heater 100, the water heater 100 can trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature. Therefore, the water heater 100 can reduce energy expenditure during periods with no predicted hot water consumption while maintaining the ability to meet unexpected demand via rapid inline heating.

In one variation, the water heater 100 can: detect hot water consumption exceeding the expected hot water consumption volume during the hot water consumption event; and trigger the inline heater 140 to heat water exiting the water tank 108 toward the target supply temperature. The water heater 100 can then, upon conclusion of the hot water consumption event, deactivate the inline heater 140.

For example, prior to a hot water consumption event associated with an expected hot water consumption volume of 25 gallons (e.g., for a single shower), the water heater 100 can trigger the heat pump 120 to heat 30 gallons of water (i.e., including five gallons of extra water) toward the target supply temperature. Then, during the hot water consumption event, the water heater 100 can: detect water consumption based on signals output by the flow rate sensor 128; in response to detecting water consumption surpassing 25 gallons of water, trigger the inline heater 140 to rapidly heat water exiting the water tank 108; and, at the mixing valve 150, combine cold water with hot water exiting the inline heater 140.

Additionally, the water heater 100 can update the water consumption forecast to represent actual water consumption responsive to unexpected, reduced, and/or excess water consumption deviating from the water consumption forecast. For example, in the preceding example, in response to detecting a hot water consumption volume of 50 gallons (i.e., surpassing the expected hot water consumption volume of 25 gallons) during instances of the hot water consumption event over an interval of 30 days, the water heater 100 can store the hot water consumption volume of 50 gallons in association with the hot water consumption event in the water consumption forecast.

Accordingly, the water heater 100 can: rapidly respond to water consumption deviating from the water consumption forecast to maintain hot water availability; deactivate the inline heater 140 upon conclusion of the unexpected hot water consumption event; and continuously refine the water consumption forecast (e.g., throughout the life-cycle of the instance of the water heater 100) to heat water according to evolving water consumption patterns within the building. Therefore, the water heater 100 can: enhance user satisfaction by consistently supplying hot water to the building during each hot water consumption event; and increase cost savings and reduce unnecessary energy consumption by aligning heating cycles with actual demand.

28. Guest Mode

In one variation, the water heater 100 can: receive an input from the user (e.g., via the controller) indicating an increased quantity of users (e.g., guests) for a particular time period; and temporarily update the water consumption forecast to accommodate the increased quantity of users, such as by recalculating expected hot water consumption volumes and/or predicting new hot water consumption events (i.e., periods previously not defined in the water consumption forecast).

In one example, an instance of the water heater 100 serves two users in a home. In this example, the water heater 100 can: receive selection of a quantity of four users to be served by the instance of the water heater 100 for one week; identify a hot water consumption event, between 7:00 PM and 7:30 PM each weekday (i.e., Monday-Friday), associated with an expected hot water consumption volume of 25 gallons (e.g., for a single washing machine cycle); recalculate an expected hot water consumption volume of 40 gallons between 7:00 PM and 7:30 PM (e.g., for two washing machine cycles) based on the quantity of four users; and reschedule activation of the heat pump 120 at 6:00 PM (e.g., rather than 6:30 PM) each weekday to heat water stored in the water tank prior to the water consumption event at 7:00 PM.

Additionally, in this example, the water heater 100 can: predict a new hot water consumption event, between 6:00 AM and 8:00 AM each weekday, and an expected hot water consumption volume of 25 gallons (e.g., for a single shower); and schedule activation of the heat pump 120 at 5:15 PM each weekday to heat water stored in the water tank prior to the new hot water consumption event 6:00 AM.

Alternatively, in this variation, in response to receiving selection of an increased quantity of users served by the system, the water heater 100 can: activate the heat pump 120 to heat water to the target holding temperature (e.g., between 120° and 160° Fahrenheit); and implement the mixing valve 150 to mix cold water (e.g., from the cold water supply) with the hot water exiting the water tank 108, as described above. For example, the water heater 100 can trigger the heat pump 120 to heat water toward the target holding temperature prior to each previously-predicted hot water consumption event, newly-predicted hot water consumption event, and/or over a particular interval (e.g., between 6:00 AM and 9:00 PM each day for the indicated duration of additional users).

Alternatively, in this variation, in response to receiving selection of an increased quantity of users served by the system, the water heater 100 can: increase the target holding temperature for maintaining water stored in the water tank 108; and implement the mixing valve 150 to mix cold water with the hot water exiting the water tank 108, as described above. Thus, the water heater 100 can implement the inline heater 140 and/or the heat pump 120 to heat water to the target holding temperature (or a maximum water temperature) and rapidly adjust the temperature of the water (i.e., via the mixing valve 150), thereby increasing the volume of hot water available to the user(s) to meet increased demand while avoiding risk of scalding.

In another variation, rather than receiving an indication of additional users from the user, the water heater 100 can: identify consistent water consumption (e.g., over a three-day interval) surpassing expected hot water consumption volumes; and temporarily update the water consumption forecast to increase hot water consumption volumes associated with the predicted hot water consumption events. Therefore, the water heater 100 can adapt the heating schedule based on detected changes in water consumption and extend the available hot water range to accommodate temporary increases in demand, such as from additional users (e.g., guests) within the building.

29. Recirculation Schedule

In one variation, as shown in FIG. 12, Blocks of the method S100 recite: deriving a recirculation duration for the recirculation pump 160 to purge cooled water from the building in Block S164; activating the recirculation pump 160 to circulate hot water from a water tank 108 of the water heater 100 to the building during the recirculation duration in Block S160; and deactivating the recirculation pump 160 in Block S162. In this variation, the water heater 100 can derive a recirculation schedule for activating the recirculation pump 160 prior to hot water consumption events. The water heater 100 can then: trigger the recirculation pump 160 to purge hot water supply lines within the building prior to hot water consumption events according to the recirculation schedule; and deactivate the recirculation pump 160 immediately prior to the hot water consumption event to reduce unnecessary circulation and energy expenditure. In particular, the water heater 100 can selectively activate and deactivate the recirculation pump 160 according to the recirculation schedule, such that hot water reaches each fixture prior to each hot water consumption event, and the recirculation pump 160 minimizes unnecessary recirculation.

In this variation, at a first time, the water heater 100 can trigger the recirculation pump 160: to draw cooled water from the building to the water tank 108; and to supply water, proximal the target supply temperature, to the building. Then, at a second time following the first time, the water heater 100 can: detect a second water temperature of water, drawn to the water tank 108 by the recirculation pump 160, proximal the target supply temperature; and derive a recirculation duration for the recirculation pump 160 to purge cooled water from the building based on a difference between the first time and the second time.

In particular, the water heater 100 can trigger the recirculation pump 160: to draw cooled water to the water tank 108 via a cold water return line of a fixture; and to supply hot water (i.e., proximal the target supply temperature) to the fixture via a hot water supply line of the fixture. The water heater 100 can then: initiate a timer for detecting water entering the water tank 108 proximal the target supply temperature; access a set of water temperature data recorded by a temperature sensor 114 proximal the cold water inlet 104 of the water tank 108; and, in response to detecting a water temperature (i.e., of the water returning to the water tank 108) proximal the target supply temperature, record the recirculation duration (i.e., the duration required to purge and/or circulate water within the building).

The water heater 100 can then: predict a hot water consumption event within the building; trigger the recirculation pump 160 to purge cooled water from the building during the recirculation duration to supply water, proximal the target supply temperature, to the building prior to the hot water consumption event; and deactivate the recirculation pump 160. In particular, the water heater 100 can activate the recirculation pump 160 at a recirculation pump 160 activation time that precedes a start time of the hot water consumption event by at least the recirculation duration and a buffer period (e.g., fifteen minutes). The water heater 100 can then deactivate the recirculation pump 160 immediately prior to the hot water consumption event.

Accordingly, the water heater 100 can selectively activate the recirculation pump 160 prior to predicted hot water consumption events and deactivate the recirculation pump 160 upon conclusion of these hot water consumption events (i.e., rather than continuously operating the heat pump 120). Therefore, the water heater 100 can reduce energy waste associated with unnecessary pump cycling and prevent unwanted release of thermal energy into the building (e.g., particularly during summer months) while maintaining reliable delivery of hot water at fixtures preceding predicted demand.

29.1 Fixture-Specific Recirculation

In one variation, the water heater 100 can: predict a fixture corresponding to a particular hot water consumption event, such as based on the average volume of water consumed during similar past events; and trigger the recirculation pump 160 to selectively recirculate water to the fixture prior to instances of the hot water consumption event at the fixture. For example, the water heater 100 can implement methods and techniques described below to predict a fixture, in a set of fixtures located within the building, corresponding to the hot water consumption event based on observed water consumption patterns (e.g., start times, end times, consumption volumes).

Additionally or alternatively, the water heater 100 can implement methods and techniques described above to predict a hot water consumption event within the building and an average hot water consumption volume during the hot water consumption event. The water heater 100 can then predict the fixture that corresponds to the hot water consumption event based on the average hot water consumption volume (e.g., 1.5 gallons for a handwashing cycle).

The water heater 100 can then, during an initial time period preceding the hot water consumption event: trigger a recirculation valve fluidly coupled to the fixture to open; trigger the recirculation pump 160 to supply water, proximal the target supply temperature, to the fixture; trigger the recirculation valve to close; and deactivate the recirculation pump 160.

Therefore, the water heater 100 can selectively recirculate hot water to a particular fixture preceding a hot water consumption event at this fixture to deliver hot water on demand while avoiding unnecessary recirculation throughout the building.

29.2 Recirculation for Freeze-Risk Mitigation

In one variation, the recirculation pump 160 can selectively recirculate hot water to hot water supply lines at risk of freezing. In particular, the water heater 100 can implement methods and techniques described above to access air temperatures of outdoor air proximal the building and/or water temperatures within hot water supply lines within the building. The water heater 100 can then selectively activate the recirculation pump 160 in response to a water temperature below a freeze-risk threshold (e.g., 40° Fahrenheit) and/or an outdoor air temperature indicating a sustained freeze risk (e.g., below 32° Fahrenheit).

In one example, the water heater 100 can: detect a water temperature of water in a hot water supply line within the building; and, in response to the water temperature falling below a freeze-risk temperature, trigger the recirculation pump 160 to supply water, proximal the target supply temperature water (e.g., at 100° Fahrenheit), to the hot water supply line to prevent the supply line from freezing.

In another example, in response to an outdoor air temperature falling below a threshold air temperature (e.g., 32° Fahrenheit) and a water temperature in a hot water supply line falling below a threshold water temperature (e.g., 32° Fahrenheit), the water heater 100 can activate the recirculation pump 160 to supply water (e.g., proximal the target supply temperature) to the hot water supply line. Additionally or alternatively, in the preceding example, the water heater 100 can continuously activate the recirculation pump 160 to purge the supply line with the supply of hot water until the external air temperature exceeds the threshold air temperature.

In another example, the water heater 100 can selectively recirculate hot water to hot water supply lines during null hot water consumption windows (i.e., periods of zero water consumption) to prevent these hot water supply lines from freezing during idle periods. In this example, during a null hot water consumption window, the water heater 100 can access an outdoor air temperature of air proximal the building. In response to the outdoor air temperature falling below the freeze-risk temperature, the water heater 100 can: trigger a set of valves (e.g., configured to direct flow toward one or more hot water supply lines), arranged downstream the water tank 108, to open; and activate the recirculation pump 160 to circulate heated water between the set of valves and the water tank 108. Thus, the water heater 100 can leverage the water temperature within the building and the external air temperature to purge vulnerable supply lines with hot water.

30. Cleaning Module

In one variation, as shown in FIG. 12, the water heater 100 can execute a cleaning module for heating the water stored in the water tank 108 to a sterilization temperature (i.e., exceeding the target supply temperature) to clean (e.g., sterilize, or disinfect) the water tank 108. For example, the water heater 100 can trigger one or more heating elements to maintain water stored in the water tank 108 at a sterilization temperature of 160° Fahrenheit for fifteen minutes.

In one variation, the water heater 100 can execute the cleaning module during intervals characterized by an absence of expected hot water usage (or “null hot water consumption windows”) to avoid intersection with predicted hot water consumption events. In this variation, the water heater 100 can implement methods and techniques described above to predict a null hot water consumption window within the building. Then, during the null hot water consumption window, the water heater 100 can trigger the heat pump 120 to heat water stored in the water tank 108 toward the sterilization temperature.

In one example, the water heater 100 can: predict a null hot water consumption window (e.g., a time window corresponding to a flow rate of zero) between 2:00 AM and 2:30 AM; estimate a heating duration of 30 minutes to heat water stored in the water tank 108 to a sterilization temperature of 160° Fahrenheit; and schedule activation of the heat pump 120 at 1:30 AM (e.g., on the next day). Thus, the water heater 100 can execute the cleaning module during periods of zero water usage and implement the mixing valve to prevent delivery of water at the sterilization temperature to fixtures, thereby mitigating risk of scalding during execution of high-temperature cycles.

Additionally, in this variation, in response to detecting flow of water from the water heater 100 (i.e., during execution of the cleaning module), the mixing valve 150 can combine cold water with hot water exiting the water tank 108, proximal the sterilization temperature, to cool water to the target supply temperature. Therefore, the water heater 100 can execute high-temperature cleaning cycles without disrupting normal water usage or introducing scalding risks at fixtures, while maintaining internal hygiene of the water tank 108 across extended operating periods.

In another variation, the water heater 100 can schedule the cleaning module coincident with a previously-scheduled heating cycle prior to an upcoming hot water consumption event. In this variation, the water heater 100 can: predict a hot water consumption event within the building; access a water temperature of water stored in the water tank; access a sterilization hold duration for maintaining water stored in the water tank at the sterilization temperature greater than the target supply temperature; estimate a heating duration to heat water stored in the water tank to the sterilization temperature based on a difference between the water temperature and the sterilization temperature; and trigger the heat pump to heat water stored in the water tank to the sterilization temperature prior to the hot water consumption event by at least the sterilization hold duration and the heating duration.

In one example, the water heater 100 can: identify an upcoming hot water consumption event with a fifteen minute heating duration scheduled between 5:45 AM and 6:00 AM to heat water to the target supply temperature of 120° Fahrenheit; estimate a new heating duration of 30 minutes to heat water stored in the water tank 108 to the sterilization temperature of 160° Fahrenheit; and reschedule activation of the heat pump 120 at 5:30 AM. Additionally, in this example, in response to unexpected water consumption starting at 5:45 AM, the water heater 100 can mix cold water (e.g., from the cold water supply) with hot water exiting the water tank 108 via the mixing valve 150 to cool water to the target supply temperature. Thus, the water heater 100 can: execute the cleaning module coincident with a previously-scheduled heating cycle to reduce redundant heating operations and minimize total energy expenditure; and rapidly adjust the temperature of the water exiting the water heater 100 responsive to unexpected water consumption during the cleaning module.

In another variation, the water heater 100 can schedule the cleaning module coincident with a cost-efficient period. In one example, the water heater 100 can: identify a cost-efficient period between 3:00 AM and 5:00 AM (e.g., in a local energy guide); estimate a heating duration of one hour to heat water stored in the water tank 108 to the sterilization temperature of 160° Fahrenheit; and schedule activation of the heat pump 120 at 4:00 AM (i.e., within the cost-efficient period).

Alternatively, in another variation, the water heater 100 can reset a timer for the cleaning module upon completion of an inadvertent cleaning module. In one example, the water heater 100 can: initiate a timer (e.g., a seven day timer) for executing a cleaning module; and, in response to the water temperature exceeding the sterilization temperature for a threshold duration (e.g., during a scheduled heating cycle), reset the timer. Alternatively, in response to the timer expiring prior to execution of a cleaning module, the water heater 100 can implement methods and techniques described above to schedule the cleaning module. Therefore, the water heater 100 can align the cleaning module with predicted null hot water consumption windows, scheduled heating cycles, and/or cost-efficient time periods to sterilize the water tank 108 while minimizing energy expenditure and reducing the risk of scalding during unexpected water consumption.

31. Digital Model

In one variation, the water heater 100 can derive a digital model of the building that represents each fixture (e.g., fixture type, fixture location) within the building, such as by associating consistent water consumption to a particular feature. In this variation, the water heater 100 can: access the set of flow rate data recorded by the flow rate sensor 128; identify a hot water consumption event associated with consistent water consumption (e.g., the same hot water consumption volume between 7:00 AM and 8:00 AM each Monday over the previous five Mondays); interpret a fixture corresponding to the hot water consumption event based on the identified consistent water consumption; and annotate the digital model with the fixture corresponding to the hot water consumption event.

In one example, the water heater 100 can: predict a first hot water consumption event—associated with a hot water consumption volume of 5 gallons—between 7:00 PM and 7:45 PM each Monday during the previous five weeks; associate the first hot water consumption event with a dishwasher (i.e., completing a single dishwashing cycle) based on the hot water consumption volume of 5 gallons; and annotate the digital model with the dishwasher corresponding to the first hot water consumption event between 7:00 PM and 7:45 PM each Monday.

In one variation, the water heater 100 can disaggregate water consumption data between two different fixtures based on distinct usage patterns. For example, in the preceding example, the water heater 100 can: identify a second hot water consumption event—associated with a hot water consumption volume of 15 gallons—between 8:00 PM and 8:15 PM each Monday during the previous five weeks; associate the second hot water consumption event with a shower fixture (i.e., for completing a single shower) based on hot water consumption volume of 15 gallons; and annotate the digital model with the shower fixture corresponding to the second hot water consumption event between 8:00 PM and 8:15 PM each Monday.

In this variation, the water heater 100 can then selectively activate the recirculation pump 160 to purge hot water supply lines of these fixtures at different times. For example, in the preceding example, the water heater 100 can: activate the recirculation pump 160 at a first recirculation pump 160 activation time preceding the first hot water consumption event between 7:00 PM and 7:45 PM each Monday to purge a first hot water supply line of the dishwasher with water proximal the target supply temperature; and activate the recirculation pump 160 at a second recirculation pump 160 activation time preceding the second hot water consumption event between 8:00 PM and 8:15 PM each Monday to purge a second hot water supply line of the shower fixture with water proximal the target supply temperature. Therefore, by activating the recirculation pump 160 at distinct times aligned with fixture-specific consumption events, the water heater 100 can reduce energy expenditure associated with continuous or unnecessary recirculation cycles, while reducing hot water delivery latency at fixtures throughout the building.

In another variation, the water heater 100 can activate the inline heater 140 to rapidly respond to unexpected and/or excess water consumption outside of the water consumption forecast and digital model. For example, in the preceding example, in response to detecting water consumption surpassing the expected hot water consumption volume of 15 gallons between 8:00 PM and 8:15 PM on a Monday, the water heater 100 can trigger the inline heater 140 to rapidly heat water exiting the water tank 108. The water heater 100 can then: detect conclusion of the hot water consumption event at 8:20 PM; deactivate the inline heater 140; and record a new hot water consumption volume of 30 gallons between 8:00 PM and 8:20 PM.

In response to detecting consistent water consumption of 15 gallons each Monday between 8:05 PM and 8:20 PM over the following five weeks, the water heater 100 can: predict a new hot water consumption event between 8:05 PM and 8:20 PM each Monday; associate the new hot water consumption event with a second shower fixture (i.e., for completing a single shower) based on the hot water consumption volume of 15 gallons; and annotate the digital model with the second shower fixture corresponding to the new hot water consumption event between 8:05 PM and 8:20 PM each Monday.

In another variation, the water heater 100 can leverage user inputs to disaggregate water consumption data between different fixtures, such as by matching a hot water consumption event with a particular routine and fixture specified by the user and associating the fixture with the hot water consumption event.

Accordingly, the water heater 100 can accurately model the distribution of water consumption within the building and schedule activation of the recirculation pump 160 to supply hot water to a specific fixture prior to a hot water consumption event at the fixture. Therefore, the water heater 100 can increase energy efficiency by reducing unnecessary heating cycles, while reducing hot water delivery latency, thus improving overall system efficiency and user comfort.

31.1 Variation: Leak Detection

In one variation, the water heater 100 can: detect water consumption characteristic of a water leak, such as a relatively low flow rate (e.g., 0.1 gallons per minute) occurring outside of the predicted hot water consumption events; and serve an alert, indicating a potential water leak, to the user. For example, the water heater 100 can: detect an unexpected flow rate of 0.1 gallons per minute between 2:00 AM and 2:30 AM on a Wednesday (i.e., outside of predicted hot water consumption events); characterize the flow rate between 2:00 AM and 2:30 AM as a potential water leak (i.e., consistent, low flow rate not typically associated with any known fixture usage); generate an alert indicating a potential water leak occurring between 2:00 AM and 2:30 AM; and serve the notification to the user (e.g., via a user interface). Therefore, the water heater 100 can identify potential water leaks by monitoring unexpected, consistent low flow rates from the hot water system that fall outside of predicted hot water consumption events, thereby mitigating potential damage resulting from a water leak.

31.2 Variation: Recommendations Based on Digital Model

In one variation, the water heater 100 can leverage the digital model to generate cost efficiency and/or operational recommendations for the user. In one example, the water heater 100 can: predict a hot water consumption event, between 2:00 PM and 3:00 PM, associated with an expected hot water consumption volume of 25 gallons by a washing machine (e.g., for a single washing machine cycle); identify a cost-efficient period between 7:00 PM and 8:00 PM (e.g., in a local energy guide); generate a notification recommending operation of the washing machine during the cost-efficient period; and serve the notification to the user (e.g., via a user interface).

In another example, for a particular day with a forecast ambient temperature (e.g., 90° Fahrenheit) above a threshold temperature (e.g., 75° Fahrenheit), the water heater 100 can: predict a high-cost period based on predicted high energy consumption (e.g., resulting from increased electricity usage); generate a notification recommending reduction of water consumption during the high-cost period; and serve the notification to the user.

In another example, the water heater 100 can: predict a decreased power availability period (e.g., based on energy consumption data); generate a notification recommending reduction of water consumption during the decreased power availability period; and serve the notification to the user.

In another example, for a particular day with a forecast ambient temperature (e.g., 5° Fahrenheit) below a threshold temperature (e.g., 20° Fahrenheit), the water heater 100 can: generate a notification recommending activation of the recirculation pump 160 to purge hot water supply lines within the building with a supply of hot water (e.g., at 100° Fahrenheit) to prevent these hot water supply lines from freezing; and serve the notification to the user. Therefore, the water heater 100 can generate recommendations for the user: to shift or adjust water usage to coincide with cost-efficient periods (i.e., to reduce energy expenses); to shift or adjust water usage in anticipation of high-cost energy periods or power outages (i.e., to reduce operational disruptions); and to execute preventative actions, such as activating the recirculation pump 160 in cold weather, to protect the water heater 100 and/or hot water supply lines from potential damage.

The systems and methods described herein can be embodied and/or implemented at least in part as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions can be executed by computer-executable components integrated with the application, applet, host, server, network, website, communication service, communication interface, hardware/firmware/software elements of a user computer or mobile device, wristband, smartphone, or any suitable combination thereof. Other systems and methods of the embodiment can be embodied and/or implemented at least in part as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions can be executed by computer-executable components integrated by computer-executable components integrated with apparatuses and networks of the type described above. The computer-readable medium can be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computer-executable component can be a processor, but any suitable dedicated hardware device can (alternatively or additionally) execute the instructions.

As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the embodiments of the invention without departing from the scope of this invention as defined in the following claims.