DEHUMIDIFICATION SYSTEM AND HEAT EXCHANGER FOR THE SAME

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Ser. No. 63/481,100, filed Jan. 23, 2023, the entire content of which is incorporated herein by reference.

BACKGROUND

The present invention relates to a dehumidification system for refrigeration systems and heating, ventilation, and air conditioning systems and, more particularly, to a heat exchanger for these systems.

Existing dehumidification systems are often used to extract moisture from air so that conditions in a space (e.g., a home, a retail store, warehouse, etc.) are more comfortable. These systems typically include a first heat exchanger (e.g., an evaporator) with one or more coils that cool a fluid via heat exchange with a refrigerant or coolant, and a second heat exchanger (e.g., a reheat coil) that is separate from and downstream of the first heat exchanger to reheat the fluid. It has been standard practice in the industry to size the reheat coil at 50% capacity of the primary coolant coil.

SUMMARY

In some aspects, the techniques described herein relate to a dehumidification system including: a heat exchanger including a coolant coil having a coolant coil section and a reheat coil having a reheat coil section, the coolant coil section and the reheat coil section intertwined with each other within an envelope of the heat exchanger; a coolant circuit including a condenser fluidly connected to the coolant coil, the coolant circuit configured to circulate a refrigerant to cool an airflow flowing through the heat exchanger; and a reheat circuit including a heater operably coupled to the reheat coil, the reheat circuit configured to circulate a reheat fluid to heat the airflow, wherein the intertwined nature of the coolant coil section and the reheat coil section is configured to dehumidify the airflow within the heat exchanger envelope.

In some aspects, the techniques described herein relate to a heat exchanger for a dehumidification system, the heat exchanger including: a first zone defining a first airflow section configured to receive a portion of an airflow passing through the heat exchanger, the first zone extending parallel to an air inlet of the heat exchanger; a second zone defining a second airflow section configured to receive another portion of the airflow passing through the heat exchanger, the second zone extending parallel to the air inlet; a coolant coil including a first coolant coil section and a second coolant coil section each configured to cool the airflow; and a reheat coil including a first reheat coil section and a second coil section each configured to heat the airflow, wherein the first zone includes the first coolant coil section and the first reheat coil section to at least partially dehumidify the airflow within the first zone.

In some aspects, the techniques described herein relate to a heat exchanger for a dehumidification system, the heat exchanger including: a plurality of zones, each of the plurality of zones defining respective airflow sections configured to receive a portion of an airflow passing through the heat exchanger; a coolant coil including a plurality of coolant coil sections configured to cool the airflow, a first coolant coil section of the plurality of coolant coil sections disposed in a first zone of the plurality of zones and having a refrigerant inlet, and a second coolant coil section of the plurality of coolant coil sections disposed in a second zone of the plurality of zones and having a coolant coil outlet; and a reheat coil configured to heat the airflow, the reheat coil including a plurality of reheat coil sections, a first reheat coil section of the plurality of reheat coil sections disposed in a third zone of the plurality of zones and having a reheat fluid inlet, and a second reheat coil section of the plurality of reheat coil sections disposed in a fourth zone of the plurality of zones and having a reheat outlet, wherein each of the plurality of zones includes a portion of the coolant coil and a portion of the reheat coil to at least partially dehumidify the airflow.

In one aspect, the present invention provides a dehumidification system including a heat exchanger including a fluid coolant coil and a fluid reheat coil intertwined with each other within the profile of the heat exchanger to provide cooperative cooling and reheat functionality for dehumidification of an airflow.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary dehumidification system embodying the present invention and including an air handler unit.

FIG. 2 is a schematic view of the air handler of the dehumidification system of FIG. 1.

FIG. 3 is a schematic view of another dehumidification system embodying the present invention.

FIG. 4 is a schematic view of another dehumidification system embodying the present invention.

FIG. 5 is a schematic view of another dehumidification system embodying the present invention.

FIG. 6 is a schematic view of another dehumidification system embodying the present invention.

FIG. 7 is a schematic view of an exemplary heat exchanger embodying the present invention.

FIG. 8 is a schematic view of another exemplary heat exchanger system embodying the present invention.

FIG. 9 is a schematic view of another exemplary heat exchanger system embodying the present invention.

FIG. 10 is a schematic view of another exemplary heat exchanger system embodying the present invention.

FIG. 11 is a schematic view of another exemplary heat exchanger system embodying the present invention.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary dehumidification system 10 including a coolant circuit 18 configured to circulate a refrigerant or coolant (e.g., a coolant fluid; interchangeably referred to as a coolant fluid or a refrigerant), a reheat circuit 22 configured to circulate a coolant or refrigerant (e.g., reheat fluid), and an air handler unit 26. The refrigerant and the reheat fluid may be the same fluid or different fluids. The air handler unit 26 has a heat exchanger 30 and a controller 34. The dehumidification system 10 may be used to condition air in an enclosed space (e.g., a commercial space such as a warehouse or retail location, or a residential space). In some embodiments, the dehumidification system 10 may include the heat exchanger 30 in a housing or structure other than the air handler unit 26. It will be appreciated that dehumidification can be achieved via a heat function (e.g., with a heater such as an electric heater or other heater), a reheat function (e.g., with a heat pump), a recovery heat function (e.g., reusing heated air from the supplied airstream), and a heat capture function (e.g., capturing any other source of heat in the system with an energy recovery ventilation process). These heat functions may be collectively referred to as “reheat” in the Description and the Claims.

The refrigerant and the reheat fluid may be any suitable fluid that facilitates heat transfer between the respective coolant and reheat fluids and an airflow passing through the heat exchanger 30. The refrigerant and the reheat fluid may or may not undergo phase transitions (e.g., between liquid and gas). Each of the refrigerant and the reheat fluid is transported through the dehumidification system 10 by a plurality of pipes or lines 38. The lines 38 may include pipe sections that are insulated to prevent heat transfer between the fluid 14 and the environment.

The coolant circuit 18 includes a condenser 42 and a coolant coil 116 is disposed in the heat exchanger 30. The condenser 42 is located downstream of the heat exchanger 30 and is configured to cool the refrigerant. The coolant coil 116 is configured to allow refrigerant to be circulate through the heat exchanger 30. The coolant coil 116 includes a coolant line inlet 46 and a coolant line outlet 50. The coolant line inlet 46 may include a flow control device 54 (e.g., a thermal expansion valve, an electronic expansion valve, etc.) configured to control the amount and the pressure of the refrigerant that enters the coolant coil 116. It will be appreciated that the coolant line inlet 46 may define or include an inlet header and/or have an accumulator or reservoir, and the coolant line outlet 50 may define or include a suction header and/or a reservoir.

In use, the cooling fluid flows from the condenser 42 toward the heat exchanger 30. The refrigerant enters the coolant coil 116 of the heat exchanger 30 via the coolant line inlet 46. The amount of refrigerant that enters the coolant coil 116 is controlled by the flow control device 54. The refrigerant is in heat exchange relationship with the airflow 98 flowing through the heat exchanger 30 to cool the airflow 98. The refrigerant is discharged from the heat exchanger 30 and the coolant coil 116 via the coolant line outlet 50, and the refrigerant flows to the condenser 42 to be cooled via heat exchange with a fluid medium (air, water, etc.).

The reheat circuit 22 includes a heat pump 62 (e.g., in the form of a heat exchanger) and a reheat coil 120 is disposed in the heat exchanger 30. The heat pump 62 is configured to reheat the reheat fluid. The heat pump 62 is located downstream of the heat exchanger 30. The reheat coil 120 is configured to allow the reheat fluid to be circulate through the heat exchanger 30. The reheat coil 120 includes a reheat line inlet 66 and a reheat line outlet 70. The reheat line inlet 66 may include a flow control device 74 (e.g., a thermal expansion valve, an electronic expansion valve, etc.) configured to control the amount and the pressure of the reheat fluid that enters the reheat coil 120. It will be appreciated that the reheat line inlet 66 may define or include an inlet header and/or have an accumulator or reservoir, and the reheat line outlet 70 may define or include a suction header and/or a reservoir.

In use, the reheat fluid flows from the heat pump 62 toward the heat exchanger 30. The reheat fluid enters the reheat coil 120 of the heat exchanger 30 via the reheat line inlet 66. The amount of reheat fluid that enters the reheat coil 120 is controlled by the flow control device 74. The reheat fluid is in heat exchange relationship with the airflow 98 flowing through the heat exchanger 30 to heat (e.g., reheat) the airflow 98. The reheat fluid is discharged from the heat exchanger 30 and the reheat coil 120 via the reheat line outlet 70, and the reheat fluid returns to the heat pump 62 to be reheated via heat exchange with a fluid medium.

The coolant coil 116 is configured to cool an airflow moving through the air handler unit 26, and the reheat coil 120 is configured to heat or reheat the airflow to remove moisture from the airflow (i.e., to dehumidify the airflow). In some embodiments, the coolant circuit 18 is configured to cool the airflow to a temperature between approximately 36 and 55 degrees Fahrenheit. In other embodiments, the coolant circuit 18 is configured to cool the airflow to a temperature of 46 degrees. In some circumstances, the airflow may be slightly heated by the reheat coil 120. In some embodiments, the reheat circuit 22 may heat the airflow to a temperature between approximately 72 and 105 degrees Fahrenheit. In other embodiments, the reheat circuit 22 may heat the airflow to a temperature between approximately 85 and 100 degrees Fahrenheit. The airflow may cool slightly after exiting the heat exchanger 30. It will be appreciated that the coolant circuit 18 may cool the airflow to a temperature outside of the range of 36 to 55 degrees. It will also be appreciated that the reheat circuit 22 may heat the airflow to a temperature outside of the range of 85 to 100 degrees.

With reference to FIG. 2, the air handler unit 26 includes at least one air inlet (e.g., an outdoor air inlet 80), a fan 104, and a supply air outlet 110. The air handler unit 26 may include the outdoor air inlet 80 via which an outdoor airflow 84 may enter the air handler unit 26 to be conditioned by the heat exchanger 30. The outdoor air inlet 80 may include an outdoor air temperature sensor 156 that measures the temperature of the outdoor airflow 84. The outdoor airflow 84 may or may not be hot and humid air. The air handler unit 26 may include a return air inlet 88, alone or in combination with the outdoor air inlet 80, via which a return airflow 92 may be directed through the heat exchanger 30 from an indoor space to be conditioned by the dehumidification system 10. The return air inlet 88 may include a return air temperature sensor 100 that measures the temperature of the return airflow 92. The return airflow 92 may be less hot and less humid than the outdoor airflow 84. The air handler unit 26 may include a damper 96 that is movable between different positions to control the amount of outdoor airflow 84 and the amount of return airflow 92 that enters the air handler unit 26. In embodiments with the damper 96, the damper 96 may have a position in which the outdoor airflow 84 and the return airflow 92 are mixed to form an airflow 98 that flows through the air handler unit 26.

The fan 104 is located in the air handler unit 26 between the outdoor air inlet 80 and the return air inlet 88 to circulate the airflow 98 through the air handler unit 26. The fan 104 may be a variable speed fan that can increase and decrease in speed to control the flow of the airflow 98 through the air handler unit 26.

The heat exchanger 30 conditions the airflow 98 via the coolant coil 116 and the reheat coil 120. It will be appreciated that the heat exchanger 30 may include a plurality of coolant coils 116 and a plurality of reheat coils 120 that extend through the heat exchanger 30 in parallel. One or more sections of the coolant coil 116 and one or more sections of the reheat coil 120 are intertwined (e.g., interlaced) such that the airflow 98 can be cooled by the coolant coil 116 and heated by the reheat coil 120 within the same heat exchanger envelope to enhance the dehumidification process. The intertwined state of the coolant coil 116 and the reheat coil 120 is described in detail below. In some embodiments, the heat exchanger 30 is a fin and tube heat exchanger. It will be appreciated that the heat exchanger 30 maybe a microchannel heat exchanger or another form of heat exchanger.

The airflow downstream of the heat exchanger 30 defines a supply airflow 108 of dry, warm air that is discharged from the heat exchanger 30 through the supply air outlet 110. The supply air outlet 110 may be fluidly connected to a HVAC system (not shown) that directs the supply airflow 108 to one or more indoor spaces to be conditioned. The supply air outlet 110 may include a supply air temperature sensor 112 that measures the temperature of the supply airflow 108.

The controller 34 allows the user to set a desired temperature and overall conditions for the indoor space. In some constructions, the controller 34 may be a thermostat. The controller 34 may adjust the supply airflow 108 to ensure that the indoor space meets desired conditions. The temperature of the supply airflow 108 may be adjusted by altering how much the supply airflow 108 is cooled and/or reheated by the heat exchanger 30.

In some embodiments, the dehumidification system 10 may be a 3 pipe variable refrigerant flow (VRF) direct expansion system such that the system is reversible. In the reversed system, the condenser 42 heats the refrigerant such that the coolant coil 116 becomes a reheat coil. Reversing the system prevents the coolant coil 116 freezing.

FIG. 3 illustrates another exemplary dehumidification system 1010. Except as described below, the dehumidification system 1010 is similar to or the same as the dehumidification system 10. Similar features will have the same reference numeral plus 1000.

The dehumidification system 1010 includes a coolant circuit 1018, a reheat circuit 1022, an air handler unit 1026 that has a heat exchanger 1030, and a controller 1034. The coolant circuit 1018 and the reheat circuit 1022 are connected to a mode change unit 1192 and a heat pump 1194. The mode change unit 1192 (e.g., a valve or valve assembly, a control device operable to vary the mode of the heat pump 1194, etc.) can cause the heat pump 1194 to operate in a main heat mode, a secondary heat mode, a main cooling mode, or a secondary cooling mode based on the temperature of the fluid 14. The mode change unit 1192 is operable to cause the heat pump 1194 to cool the refrigerant in the coolant circuit 1018 when the mode change unit 1192 is in the main or secondary cooling modes. Compared to the secondary cooling mode, the main cooling mode may cause the refrigerant to be cooled to a lower temperature. The mode change unit 1192 is operable to cause the heat pump 1194 to heat the reheat fluid in the reheat circuit 1022 when the mode change unit 1192 is in the main or secondary heat modes. Compared to the secondary heat mode, the main heat mode may cause the reheat fluid to be heated to a higher temperature.

The coolant circuit 1018 includes a coolant coil 1116 that is disposed in the heat exchanger 1030 and that includes a coolant line inlet 1046 and a coolant line outlet 1050. The coolant line inlet 1046 may have a flow control device 1054 (e.g., a thermal expansion valve, an electronic expansion valve, etc.). The coolant line outlet 1050 may include a coolant outlet sensor 144 to measure the temperature of the refrigerant after the refrigerant is discharged from the heat exchanger 1030.

In use, the refrigerant exits the heat pump 1194 and flows toward the heat exchanger 1030. The refrigerant enters the coolant coil 1116 via the coolant line inlet 1046. The refrigerant is in heat relationship with an airflow flowing through the heat exchanger 1030 to cool the airflow. The refrigerant is heated by heat exchange with the airflow and is discharged from the heat exchanger 1030 and the coolant coil 1116 via the coolant line outlet 1050. The coolant outlet sensor 144 measures the temperature of the refrigerant at or adjacent the coolant line outlet 1050. The coolant outlet sensor 144 transmits the refrigerant temperature to the mode change unit 1192, which may determine an amount of cooling for the refrigerant to adequately condition the supply airflow 1108. To do so, the mode change unit 1192 may change the mode of the heat pump 1194 (e.g., to the first cooling mode or the secondary cooling mode).

The reheat circuit 1022 includes a reheat coil 1120 that is disposed in the heat exchanger 1030 and that includes a reheat line inlet 1066 and a reheat line outlet 1070. The reheat line inlet 1066 may include a flow control device 1074 (e.g., a thermal expansion valve, an electronic expansion valve, etc.). The reheat line outlet 1070 may include a reheat outlet sensor 148 to measure the temperature of the reheat fluid as the fluid exits the heat exchanger 1030.

In use, the reheat fluid leaves the heat pump 1194 and flows toward the heat exchanger 1030. The reheat fluid enters the reheat coil 1120 via the reheat line inlet 1066. The reheat fluid flowing through the reheat coil 1120 is in heat exchange relationship with the airflow 1098 flowing through the heat exchanger 1030 to heat (e.g., reheat) the airflow 1098. The reheat fluid is discharged from the heat exchanger 1030 and the reheat coil 1120 via the reheat line outlet 1070. The reheat outlet sensor 148 measures the temperature of the reheat fluid in the reheat line outlet 1070. The reheat outlet sensor 148 transmits the reheat fluid temperature to the mode change unit 1192, which may determine the amount of reheat for the heat fluid to adequately condition the supply airflow 1108. To do so, the mode change unit 1192 may change the mode of the heat pump 1194 (e.g., to the first heat mode or the secondary heat mode).

The controller 1034 (e.g., a processor or microprocessor, etc., including executable instructions) allows a user to set a desired temperature and overall conditions for the indoor space. The illustrated controller 1034 includes a logic controller 136 and a system controller 140. The logic controller 136 obtains temperature information from a plurality of sensors 138 regarding the ambient environment and the indoor space to be conditioned. The logic controller 136 determines the amount of dehumidification and the temperature of the supply airflow 1108 to achieve the desired conditions for the indoor space. The logic controller 136 communicates with the system controller 140 to communicate adjustments in the system 1010 to reach the desired temperature. The system controller 140 is in communication with multiple elements of the dehumidification system 1010 to control operation of the dehumidification system 1010 based on desired parameters.

The logic controller 136 is in communication with the plurality of sensors 138 to determine how the elements of the dehumidification system 1010 should operate to achieve the desired supply air temperature in the indoor space. The sensors 138 are located at strategic points along the dehumidification system 1010. The dehumidification system 1010 may include an outdoor dew point sensor 152 and an outdoor temperature sensor 1156 that transmit information about the outdoor air to the logic controller 136. The outdoor temperature sensor 1156 may be located in the outdoor air inlet 1080. The dehumidification system 1010 may also have an indoor dew point sensor 164, a return air sensor 1100, an indoor temperature sensor 160, and a CO2 sensor 168 that transmit information about the indoor air to the logic controller 136. There may be a plurality of indoor temperature sensors 160 located around the indoor space. The coolant circuit 1018 may include a coolant inlet sensor 1058 that is connected to the coolant line inlet 1046 and is upstream of the fluid control device 1054 and the coolant outlet sensor 144 that is connected to the coolant line outlet 1050. The reheat circuit 1022 may include a reheat inlet sensor 1078 that is connected to the reheat line inlet 1066 and is upstream of the fluid control device 1074 and the reheat outlet sensor 148 that is connected to the reheat line outlet 1070. Additionally, the system 1010 may include a supply air temperature sensor 1112 that is disposed near the supply air outlet 1110. The plurality of sensors 138 allows the logic controller 136 to determine the current conditions and, as appropriate, to make adjustments to achieve the desired conditions for the indoor space. In some embodiments, the dehumidification system may only include sensors located in the indoor space (e.g., the outdoor air may only be sensed after the outdoor air enters the indoor space.

The system controller 140 may control the speed and pressure of the refrigerant and the reheat fluid. For example, the fluid control devices 1054, 1074 may be electronic expansion valves (or other similar control devices) and the system controller 140 may adjust the expansion valves 1054, 1074 to control the amount and pressure of refrigerant flowing into the coolant coil 1116 and the amount and pressure of reheat fluid flowing into the reheat coil 1120. Separately or in addition, the system controller 140 may be in communication with the damper 1096 to open and close the damper 1096 to control the amount of outdoor air 1084 that enters the air handler unit 1026 and to control the amount of return airflow 1092 that enters the air handler unit 1026. The system controller 140 also may be in communication with the fan 1104 to control or vary the speed at which the airflow 1098 flows through the air handler unit 1026. It will be appreciated that the system controller 140 may control a plurality of elements (e.g., the valves 1054, 1074) of the dehumidification system 10 to ensure that the supply airflow 1108 achieves the desired conditions for the indoor space(s).

The controller 1034 and the plurality of sensors 138 may be similar to the system controller and sensors disclosed in U.S. patent application Ser. No. 17/567,552 filed on Jan. 3, 2022, the entire content of which is incorporated herein by reference.

FIG. 4 illustrates another exemplary dehumidification system 2010. Except as described below, the dehumidification system 2010 is similar to or the same as the dehumidification system 1010. Similar features will have the same reference numeral plus 1000.

The dehumidification system 2010 includes a coolant circuit 2018, a reheat circuit 2022, and an air handler unit 2026 having a heat exchanger 2030. The coolant circuit 2018 includes a heat pump condenser 2200 downstream the heat exchanger 2030 and a coolant coil 2116 disposed in the heat exchanger 2030. The coolant coil 2116 includes a coolant line inlet 2046 and a coolant line outlet 2050. The coolant line inlet 2046 may include a plurality of flow control devices 2054 (e.g., a thermal expansion valve, an electronic expansion valve, etc.).

In use, the refrigerant leaves the heat pump condenser 2200 and flows toward the heat exchanger 2030. The refrigerant enters the coolant coil 2116 of the heat exchanger 2030 via the coolant line inlet 2046. The amount of refrigerant that enters the coolant coil 2116 is controlled by the plurality of flow control devices 2054. The refrigerant is in heat exchange relationship with an airflow 2098 flowing through the heat exchanger 2030 to cool the airflow 2098. The refrigerant is heated by heat exchange with the airflow 2098. The refrigerant is discharged from the heat exchanger 2030 and the coolant coil 2116 via the coolant line outlet 2050.

The reheat circuit 2022 includes a heat pump 2204 downstream of the heat exchanger 2030 (in a flow direction of the reheat fluid) and a reheat coil 2120 is disposed in the heat exchanger 2030. The reheat coil 2120 includes a reheat line inlet 2066 and a reheat line outlet 2070. The reheat line inlet 2066 may include a plurality of flow control devices 2074 (e.g., a thermal expansion valve, an electronic expansion valve, etc.).

In use, the reheat fluid leaves the heat pump 2204 and flows toward the heat exchanger 2030. The reheat fluid enters the reheat coil 2120 of the heat exchanger 2030 via the reheat line inlet 2066. The amount of reheat fluid that enters the reheat coil 2120 is controlled by the plurality of flow control devices 2074. The reheat fluid is in heat exchange relationship with the airflow 2098 flowing through the heat exchanger 2030 to heat (e.g., reheat) the airflow 2098. The reheat fluid is cooled by heat exchange with the airflow 2098. The reheat fluid is discharged from the heat exchanger 2030 and the reheat coil 2120 via the reheat line outlet 2070, and the reheat fluid flows to the heat pump 2204 to be reheated by heat exchange with a fluid medium.

FIG. 5 illustrates another exemplary dehumidification system 3010. Except as described below, the dehumidification system 3010 is similar to or the same as the dehumidification system 1010. Similar features will have the same reference numeral plus 2000.

The dehumidification system 3010 includes a coolant circuit 3018, a reheat circuit 3022, and an air handler unit 3026 that has a heat exchanger 3030. The coolant circuit 3018 includes a condenser 3042 downstream of the heat exchanger 3030 and a coolant coil 3116 that is disposed in the heat exchanger 3030. The coolant coil 3116 includes a coolant line inlet 3046 and a coolant line outlet 3050. The coolant line inlet 3046 may include a plurality of flow control devices 3054 (e.g., a thermal expansion valve, an electronic expansion valve, etc.).

In use, the refrigerant leaves the condenser 3042 and flows toward the heat exchanger 3030. The refrigerant enters the coolant coil 3116 of the heat exchanger 3030 via the coolant line inlet 3046. The amount of refrigerant that enters the coolant coil 3116 is controlled by the plurality of flow control devices 3054. The refrigerant is in heat exchange relationship with an airflow 3098 flowing through the heat exchanger 2030 to cool the airflow 3098. The refrigerant is heated by heat exchange with the airflow 3098. The refrigerant is discharged from the heat exchanger 3030 and the coolant coil 3116 via the coolant line outlet 3050, and the refrigerant flows to the condenser 3042 to be re-cooled.

The reheat circuit 3022 may include a gas or electric heater 3064, or the reheat circuit may be in heat exchange relationship at 3064 with another fluid to heat the reheat fluid. For purposes of description and the claims, the term “heater” includes any type of device or arrangement that can heat the reheat fluid. The reheat circuit also includes a reheat coil 3120. The reheat fluid in the reheat circuit 3022 may be a gas (e.g., carbon dioxide or another fluid) or a liquid. The reheat coil 3120 includes a reheat line inlet 3066 and a reheat line outlet 3070. The reheat line inlet 3066 may include a flow control device 3074. The flow control device 3074 may be an actuator valve 3074 with a bypass port, although the flow control device 3074 may take any form that can control the flow of reheat fluid into the reheat coil 3120. It should be appreciated that in some embodiments the reheat fluid may be supplied and heated outside the system.

In use, the reheat fluid enters the coolant coil 3116 of the heat exchanger 3030 via the reheat line inlet 3066. The amount of reheat fluid that enters the reheat coil 3120 is controlled by the flow control device 3074. The reheat fluid is in heat exchange relationship with the airflow 3098 to heat (e.g., reheat) the airflow 3098. The reheat fluid is cooled by heat exchange with the airflow 3098. The reheat fluid is discharged from the heat exchanger 3030 and the reheat coil 3120 via the reheat line outlet 3070. The reheat fluid then flows toward the heater 3064 to be reheated.

FIG. 6 illustrates another exemplary dehumidification system 4010. Except as described below, the dehumidification system 4010 is similar to or the same as the dehumidification system 1010. Similar features will have the same reference numeral plus 3000.

The dehumidification system 4010 includes a coolant circuit 4018, a reheat circuit 4022, and an air handler unit 4026 having a heat exchanger 4030. The coolant circuit 4018 includes a heat pump condenser 4200 downstream the heat exchanger 4030 and a coolant coil 4116 is disposed in the heat exchanger 4030. The coolant coil 4116 includes a coolant line inlet 4046 and a coolant line outlet 4050. The coolant line inlet 4046 may include a plurality of flow control devices 4054 (e.g., a thermal expansion valve, an electronic expansion valve, etc.).

In use, the refrigerant leaves the heat pump condenser 4200 and flows toward the heat exchanger 4030. The refrigerant enters the coolant coil 4116 of the heat exchanger 4030 via the coolant line inlet 4046. The amount of refrigerant that enters the coolant coil 4116 may be controlled by the plurality of flow control devices 4054. The refrigerant is in heat exchange relationship with an airflow 4098 flowing through the heat exchanger 4030 to cool the airflow 4098. The refrigerant is heated by heat exchange with the airflow 4098. The refrigerant exits the heat exchanger 4030 and the coolant coil 4116 via the coolant line outlet 4050, and the refrigerant flows to the heat pump condenser 4200 to be re-cooled.

The illustrated reheat circuit 4022 circulates water as a reheat fluid, although other reheat fluids may be circulated instead of or in addition to water. The reheat circuit 4022 includes a thermal tank 4208 that is located upstream of the heat exchanger 4030, a storage tank 4212 that is located downstream of the heat exchanger 4030, and a reheat coil 4120 that is disposed in the heat exchanger 4030. The thermal tank 4208 may include a rack heater (e.g., a gas or electric heater) that may be configured to heat the reheat fluid to a temperature between approximately 130 and 160 degrees Fahrenheit. The reheat circuit 4022 may include a line 4224 that connects the storage tank 4212 to the thermal tank 4208. The line 4224 allows the reheat fluid to flow from the storage tank 4212 to the thermal tank 4208 when the thermal tank 4208 falls below a certain level. The reheat coil 4120 includes a reheat line inlet 4066 and a reheat line outlet 4070. The reheat line inlet 4066 may include a plurality of flow control devices 4220 (e.g., an actuator valve with a bypass etc.). The reheat line inlet 4066 may also include a pump 4216. It will be appreciated that the pump 4216 may be located along the reheat line outlet 4070.

In use, the reheat fluid stored in the thermal tank 4208 is heated by the heater rack. The reheat fluid leaves the thermal tank 4208 and flows along the reheat line inlet 4066. The reheat fluid enters the reheat coil 4120 via the reheat line inlet 4066. The actuator valve 4220 may control the amount of reheat fluid that enters the reheat coil 4120. The reheat fluid is in heat exchange relationship with the airflow 4098 to heat (e.g., reheat) the airflow 4098. The reheat fluid is cooled by heat exchange with the airflow 4098. The reheat fluid is discharged from the heat exchanger 4030 and the reheat coil 4120 via the reheat line outlet 4070, and the reheat fluid flows to the storage tank 4212. The storage tank 4212 stores the cooled reheat fluid. After the thermal tank 4208 falls below a certain level, the reheat fluid may flow from the storage tank 4212 to the thermal tank 4208 via the line 4224 to be reheated and re-enter the reheat circuit 4022. As shown, the pump 4216 moves the reheat fluid through the reheat circuit 4022.

FIGS. 7-11 are described in detail with regard to the heat exchanger 30. It will be appreciated that the heat exchangers 1030, 2030, 3030, 4030 may have the same or similar features as the heat exchanger 30.

With reference to FIGS. 7-11, the heat exchanger 30 may include one or more stages of coolant coils and reheat coils depending on the desired size or capacity of the dehumidification system 10. For example, a first stage 124 and a second stage 128 may be stacked or arranged adjacent each other horizontally or vertically. The heat exchanger 30 may include fluid control devices (e.g., electronic expansion valves or other valve devices) disposed between the first stage 124 and the second stage 128 to control the amount and speed of the refrigerant and the reheat fluid that enters the second stage 128. More specifically, the heat exchanger 30 may include a refrigerant control valve 55 and a reheat fluid control valve 75 between the first stage 124 and the second stage 128. The heat exchanger 30 may have a dehumidification capacity between 3 tons to 370 tons.

The heat exchanger 30 is segmented into a plurality of zones (e.g., zones 1, 2, 3, 4, 5) that have sections of the coolant coil 116 and sections of the reheat coil 120. Each zone delineates an airflow section of the heat exchanger 30 that receives a portion of the airflow 98 through the heat exchanger 30. Each zone contains at least one section of the coolant coil 116 and at least one section of the reheat coil 120. As shown, the heat exchanger 30 has five zones, although it will be appreciated that there may be more or fewer zones depending on the desired capacity of the heat exchanger 30.

The coolant coil 116 is a continuous tube that is coupled to the coolant line inlet 46 and the coolant line outlet 50. As shown in FIG. 7, the coolant coil 116 is arranged to direct refrigerant through each of the zones (i.e., all zones) of the heat exchanger 30. It will be appreciated that the coolant coil 116 may be arranged to direct refrigerant through fewer than all of the zones. The coolant coil 116 includes a plurality of bends 118 (e.g., return bends) to transition from one zone to another zone. In the illustrated embodiment, the coolant coil 116 has four bends 118 in the first stage 124, although there may be fewer or more bends 118 depending on the arrangement of the coolant coil 116. It will be appreciated that the bends 118 may be positioned higher or lower (e.g., toward or away from the coolant line inlet 46, as viewed in FIG. 7) in a particular zone to change the amount of refrigerant that is in heat exchange relationship with the airflow 98 in the particular zone. Stated another way, the quantity of cooling coil runs in a particular zone may be changed to affect the time that the refrigerant spends in the particular zone.

The reheat coil 120 is a continuous tube that is coupled to the reheat line inlet 66 and the reheat line outlet 70. As shown in FIG. 7, the reheat coil 120 is arranged to direct reheat fluid through each of the zones (i.e., all zones) of the heat exchanger 30. It will be appreciated that the reheat coil 120 may be arranged to direct reheat fluid through fewer than all of the zones. The reheat coil 120 includes a plurality of bends 122 (e.g., return bends) to transition from one zone to another zone. In the illustrated embodiment, the reheat coil 120 has four bends 122 in the first stage 124 of the heat exchanger 30, although there may be fewer or more bends 122 depending on the arrangement of the reheat coil 120. It will be appreciated that the bends 122 may be positioned higher or lower (e.g., toward or away from the reheat line inlet 66, as viewed in FIG. 7) in a particular zone to change the amount of reheat fluid that is in heat exchange relationship with the airflow 98 in the particular zone. Stated another way, the quantity of reheat coil runs in a particular zone may be changed to affect the time that the reheat fluid spends in the particular zone. As shown in FIG. 7, each of the coolant coil 116 and the reheat coil 120 has an inlet at the top of the heat exchanger 30 and an outlet at the bottom of the heat exchanger 30 such that the refrigerant and reheat fluid flow generally downward through the coils 116, 120.

The coolant coil 116 is intertwined with the reheat coil 120 within the heat exchanger envelope, and the illustrated heat exchanger 30 includes a plurality of cross-over sections 126 (e.g., intertwined sections). The cross-over sections 126 are formed where a section of the coolant coil 116 extends across a section of the reheat coil 120, or where a section of the reheat coil 120 extends across a section of the coolant coil 116. Stated another way, portions of two or more of the zones have sections of the coolant coil 116 and sections of the reheat coil 120, and the respective bends 118, 122 of one coil (116 or 120) cross over (or under) at least one coil section of the other coil (120 or 116). The plurality of cross-over sections 126 allows the coolant coil 116 and the reheat coil 120 to have a nested or meshed relationship in which the airflow 98 is cooled and reheated within the same heat exchanger envelope. As shown in FIG. 7, the first stage 124 of the heat exchanger 30 has six cross-over sections 126, although other quantities of cross-over sections are possible and considered herein.

The cross-over sections 126 and the intertwined nature of the coolant coil 116 and the reheat coil 120 allow the heat exchanger 30 to have an improved moisture removal system by repeatedly shocking the moisture out of the airflow 98. For example, as the airflow 98 flows across the coolant coil 116 and then the reheat coil 120, the airflow 98 becomes supersaturated due to a relatively quick increase in temperature of the airflow 98. At least some of supersaturated component of the airflow 98 (i.e., water) is removed as the airflow 98 flows from the reheat coil 120 to the coolant coil 116. Due to the repeated coolant coil-reheat coil and reheat coil-coolant coil combinations in the heat exchanger 30 (i.e. considered in the direction of travel of the airflow 98 through the heat exchanger 30), the process of supersaturating the airflow 98 and subsequently removing the supersaturated component is repeated several times. The combinations of the sections for the coolant coil 116 and the reheat coil 120 also balance the load and temperature across the heat exchanger 30, which inhibits freezing of the coolant coil 116 and reduces thermal fatigue in the coils 116, 120. Liquid slugging in the compressors also may be prevented.

With reference to FIGS. 8-10, the heat exchanger 30 may include different configurations based on the flow direction of the refrigerant in the coolant circuit 18 and the direction of flow of the reheat fluid in the reheat circuit 22. In FIGS. 8-10, the airflow 98 flows from left to right. Parallel flow occurs when the refrigerant in the coolant circuit 18 and the reheat fluid in the reheat circuit 22 are flowing in the same direction as the airflow 98 though the heat exchanger 30 (e.g., the coolant and reheat fluids are flowing generally left to right across the zones). Counterflow occurs when the refrigerant in coolant circuit 18 and the reheat fluid in reheat circuit 22 flow in opposite directions of the airflow 98 though the heat exchanger 30 (e.g., the coolant and reheat fluids are flow right to left across the zones).

FIG. 8 illustrates a first arrangement of the heat exchanger 30 with the first stage 124 and the second stage 128. The coolant circuit 18 and the reheat circuit 22 are in parallel flow with the airflow 98 in the first stage 124 and the second stage 128. The refrigerant enters the coolant coil 116 in zone 1 of the first stage 124. The refrigerant then travels from zone 1 to zone 2 and zone 3 via the coolant coil 116 and corresponding bends 118. The refrigerant then flows from zone 3 to zone 5 and exits the first stage 124 at zone 4 via the coolant coil 116 and corresponding bends 118. As shown, the refrigerant follows a similar path through the zones in the second stage 128. The reheat fluid enters the reheat coil 120 in zone 2 of the first stage 124. The reheat fluid then travels from zone 2 to zone 1 and then zone 4 via the reheat coil 120 and the corresponding bends 122. The reheat fluid then flows from zone 4 to zone 3 and exits the first stage 124 at zone 5 via the reheat coil 120 and corresponding bends 122. The reheat fluid follows a similar path through the zones in the second stage 128. As shown in FIG. 8, each of the coolant coil 116 and the reheat coil 120 has an inlet at the top of the first stage 124 and the second stage 128, and an outlet at the bottom of the first stage 124 and the second stage 128 such that the refrigerant and reheat fluid flow generally downward through each of the stages 124, 128.

FIG. 9 illustrates a second arrangement of the heat exchanger 30 with the first stage 124 and the second stage 128. The coolant circuit 18 is in parallel flow with the airflow 98 in the first stage 124 and the second stage 128. The coolant coil 116 has inlets at the top of each stage 124, 128, and outlets at the bottom of each stage 124, 128. The reheat circuit 22 is in counter flow with the airflow 98 in the first stage 124 and is in parallel flow with the airflow 98 in the second stage 128. The reheat coil 120 has an inlet at the bottom of the first stage 124 and an outlet at the top of the first stage 124, and an inlet at the top of the second stage 128 and an outlet at the bottom of the second stage 128. The refrigerant enters the coolant coil 116 in zone 1 and exits the coolant coil 116 in zone 4, consistent with what is described for the first arrangement (FIG. 8). The reheat fluid enters the reheat coil 120 at zone 5 in the first stage 124. The reheat fluid travels from zone 5 to zone 3 and then to zone 4. The reheat fluid then travels from zone 4 to zone 1 and exits the reheat coil 120 at zone 2. In the second stage 128, the reheat fluid follows a parallel path consistent with the description of the first arrangement.

FIG. 10 illustrates a third arrangement of the heat exchanger 30 with the first stage 124 and the second stage 128. The coolant circuit 18 and the reheat circuit are in counter flow with the airflow 98 in the first stage 124 and are in parallel flow with the airflow 98 in the second stage 128. Each of the coolant coil 116 and the reheat coil 120 has an inlet at the bottom of the first stage 124 and an outlet at the top of the first stage 124. Each of the coolant coil 116 and the reheat coil 120 also has an inlet at the top of the second stage 128 and an outlet at the bottom of the second stage 128. The refrigerant enters the coolant coil 116 in zone 4 of the first stage 124. The refrigerant then travels from zone 4 to zone 5. Then the refrigerant travels from zone 5 to zone 3 and then zone 2 before exiting the coolant coil 116 at zone 1. In the second stage 128, the refrigerant follows a similar parallel flow path as described in the first arrangement (FIG. 8). The reheat fluid follows a path through the first stage 124 and the second stage 128 that is similar to the second arrangement (FIG. 9). In the first stage 124, the reheat fluid enters the reheat coil in zone 5 and exits the reheat coil 120 in zone 2, while in the second stage 128 the reheat fluid enters the reheat coil in zone 2 and exits the reheat coil in zone 5.

It will be appreciated that the heat exchanger 30 may have different arrangements of stages to increase or decrease the dehumidification capacity of the heat exchanger 30. With reference to FIG. 11, the heat exchanger 30 may have at least a first set of stages 180 and a second set of stages 182. The sets of stages 180, 182 may be stacked or arranged adjacent each other horizontally or vertically. As shown, the first set of stages 180 has a first stage 124a and a second stage 128a, and the second set 182 has a first stage 124b and a second stage 128b. The refrigerant may enter the coolant coil 116a in the first set of stages 180 and the coolant coil 116b in the second set 182 simultaneously or consecutively. A valve may control the flow of the refrigerant through the first and second set of stages 180, 182. The reheat fluid may enter the reheat coil 120 of the first set 180 and the reheat coil of the second set 182 simultaneously or consecutively. It will be appreciated that the flow of one or both of the refrigerant and the reheat fluid may cross between the first set of stages 180 to the second set of stages 182 and then back to the other set of stages. Other combinations of flow of the refrigerant and the reheat fluid within the envelope of the heat exchanger 30 are possible and considered herein.

As shown in FIG. 11, the refrigerant may flow between the first set of stages 180 and the second set of stages 182. For example, and as shown, the refrigerant enters the coolant coil 116 in the first stage 124a of the first set of stages 180 and in the second stage 128b of the second set of stages 182. Then, the refrigerant in the first set of stages 180 enters the second stage 128b of the second set of stages 182, and the refrigerant in the second set of stages 182 then enters the second stage 128a of the first set 180. The quantity of stages and sets of stages in the heat exchanger 30 may be altered such that dehumidification system 10 can be scalable to different-sized indoor spaces to ensure the heat exchanger 30 has adequate capacity.

The intertwined coils of the dehumidification systems 10, 1010, 2010, 3010, and 4010 may be used in compact spaces to improve the rate of moisture that is removed from the indoor space. The improved rate of moisture removal allows for a lower amount of energy to be used in dehumidifying the space and in maintaining a desired temperature in the space. The intertwined coils provide a balance of temperature across the heat exchanger. The balance of temperatures increases the durability of the system by preventing the coolant coils from freezing and preventing the thermal fatigue of the reheat coil and of the fluid control devices.

Various features and advantages of the invention are set forth in the following claims.

Clause 1. A dehumidification system comprising: a heat exchanger including a coolant coil having a coolant coil section and a reheat coil having a reheat coil section, the coolant coil section and the reheat coil section intertwined with each other within an envelope of the heat exchanger; a coolant circuit including a condenser fluidly connected to the coolant coil, the coolant circuit configured to circulate a refrigerant to cool an airflow flowing through the heat exchanger; and a reheat circuit including a heater operably coupled to the reheat coil, the reheat circuit configured to circulate a reheat fluid to heat the airflow, wherein the intertwined nature of the coolant coil section and the reheat coil section is configured to dehumidify the airflow within the heat exchanger envelope.

Clause 2. The dehumidification system of clause 1, wherein the coolant coil section is one of a plurality of coolant coil sections of the coolant coil and the reheat coil section is one of a plurality of reheat coil sections of the reheat coil, and wherein the plurality of coolant coil sections and the plurality of reheat coil sections are intertwined with each other within the heat exchanger envelope.

Clause 3. The dehumidification system of clause 1, wherein the refrigerant is configured to flow through the heat exchanger in a direction parallel to the airflow and the reheat fluid is configured to flow through the heat exchanger in the direction parallel to the airflow.

Clause 4. The dehumidification system of clause 1, wherein the refrigerant is configured to flow through the heat exchanger in a first direction opposite to the airflow and the reheat fluid is configured to flow through the heat exchanger in a second direction parallel to the airflow.

Clause 5. The dehumidification system of clause 1, wherein the refrigerant is configured to flow through the heat exchanger in a direction opposite to the airflow and the reheat fluid is configured to flow through the heat exchanger in the direction opposite to the airflow.

Clause 6. The dehumidification system of clause 1, wherein the coolant circuit includes a coolant flow control device between the condenser and the coolant coil.

Clause 7. The dehumidification system of clause 6, wherein the reheat circuit includes a reheat flow control device between the heater and the reheat coil.

Clause 8. A heat exchanger for a dehumidification system, the heat exchanger comprising: a first zone defining a first airflow section configured to receive a portion of an airflow passing through the heat exchanger, the first zone extending parallel to an air inlet of the heat exchanger; a second zone defining a second airflow section configured to receive another portion of the airflow passing through the heat exchanger, the second zone extending parallel to the air inlet; a coolant coil including a first coolant coil section and a second coolant coil section each configured to cool the airflow; and a reheat coil including a first reheat coil section and a second coil section each configured to heat the airflow, wherein the first zone includes the first coolant coil section and the first reheat coil section to at least partially dehumidify the airflow within the first zone.

Clause 9. The heat exchanger of clause 8, wherein the first coolant coil section includes a coolant coil bend and the first reheat coil section includes a reheat coil bend, and wherein the coolant coil bend crosses over or under the reheat coil bend.

Clause 10. The heat exchanger of clause 8, wherein the second zone includes the second coolant coil section and the second reheat coil section.

Clause 11. The heat exchanger of clause 10, further comprising a third zone defining a third airflow section, wherein the coolant coil includes an inlet in the first zone and an outlet in the third zone.

Clause 12. The heat exchanger of clause 11, wherein the reheat coil includes an inlet in the second zone and an outlet in a zone of the heat exchanger that is different from the third zone.

Clause 13. The heat exchanger of clause 8, wherein the coolant coil is configured to direct a refrigerant through the heat exchanger in a direction parallel to the airflow and the reheat coil is configured to direct a reheat fluid through the heat exchanger in the direction parallel to the airflow.

Clause 14. The heat exchanger of clause 8, wherein the coolant coil is configured to direct a refrigerant through the heat exchanger in a first direction opposite to a direction of the airflow and the reheat coil is configured to direct a reheat fluid through the heat exchanger in a second direction parallel to the direction of the airflow.

Clause 15. The heat exchanger of clause 8, wherein the coolant coil section is one of a plurality of coolant coil sections of the coolant coil and the reheat coil section is one of a plurality of reheat coil sections of the reheat coil, and wherein the plurality of coolant coil sections and the plurality of reheat coil sections are intertwined with each other within the heat exchanger envelope.

Clause 16. A heat exchanger for a dehumidification system, the heat exchanger comprising: a plurality of zones, each of the plurality of zones defining respective airflow sections configured to receive a portion of an airflow passing through the heat exchanger; a coolant coil including a plurality of coolant coil sections configured to cool the airflow, a first coolant coil section of the plurality of coolant coil sections disposed in a first zone of the plurality of zones and having a refrigerant inlet, and a second coolant coil section of the plurality of coolant coil sections disposed in a second zone of the plurality of zones and having a coolant coil outlet; and a reheat coil configured to heat the airflow, the reheat coil including a plurality of reheat coil sections, a first reheat coil section of the plurality of reheat coil sections disposed in a third zone of the plurality of zones and having a reheat fluid inlet, and a second reheat coil section of the plurality of reheat coil sections disposed in a fourth zone of the plurality of zones and having a reheat outlet, wherein each of the plurality of zones includes a portion of the coolant coil and a portion of the reheat coil to at least partially dehumidify the airflow.

Clause 17. The heat exchanger of clause 16, wherein at least some of the plurality of coolant coil sections and at least some of the plurality of reheat coil sections intertwined with each other within an envelope of the heat exchanger.

Clause 18. The heat exchanger of clause 17, wherein the first coolant coil section includes a coolant coil bend and the first reheat coil section includes a reheat coil bend, and wherein the coolant coil bend crosses over or under the reheat coil bend.

Clause 19. The heat exchanger of clause 16, wherein the plurality of coolant coil sections and the plurality of reheat coil sections are arranged relative to each other in the direction of airflow to repeatedly remove at least some moisture out of the airflow.

Clause 20. The heat exchanger of clause 16, wherein the heat exchanger includes a first stage and a second stage, wherein the first stage includes the coolant coil and the reheat coil, wherein the second stage includes a second coolant coil having a plurality of coolant coil sections and a second reheat coil having a plurality of reheat coil sections, and wherein the first stage is fluidly connected to the second stage via the coolant coil outlet and the reheat coil outlet.