HEAT PUMP WITH MULTI-PASS REFRIGERANT CIRCUIT

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 63/441,151, filed Jan. 25, 2023 entitled “Heat Pump with Multi-Pass Refrigerant Circuit,” which is herein fully incorporated by reference in its respective entirety.

TECHNICAL FIELD

This relates generally to refrigeration systems, including but not limited to, a Heating, ventilation, and air conditioning (HVAC) system for controlling a temperature within a compartment.

BACKGROUND

Heat pumps can use complicated refrigeration circuits and can occupy a large physical area. Additionally, to operate efficiently, heat pumps can require additional components, such as an accumulator to protect the compressor and other components of the heat pump. Existing systems can be costly and require considerable space, energy, and installation time. As such, there is a need for refrigeration systems that effectively use the limited space available and have improved performance.

SUMMARY

The refrigeration systems and methods described herein improve system performance and without increasing the space required to accommodate the refrigeration systems. In particular, the systems and methods disclosed herein improve system efficiency (e.g., Co-efficient of performance (COP)) of refrigeration systems (e.g., heat pumps) operating in heat mode and air conditioner (AC) or cooling mode. Additionally, the systems and methods disclosed herein lower the minimum operating ambient temperature while operating in heat mode, reduce the chance of compressor slugging, and reduces the size of an accumulator needed while operating in heat mode.

In one aspect, a refrigeration system includes a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, (iv) the multi-pass refrigerant circuit, and (v) the one or more valves, and a controller communicatively coupled to the one or more valves. The controller is configured to operate the refrigeration system in a plurality of modes, including a cooling mode and a heating mode. When in the cooling mode the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor. Alternatively, when in the heating mode, the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

For example, a heat pump system can include a multi-pass refrigerant circuit, such as a double pass cooling circuit, and when the heat pump system operates in cooling mode, the double pass cooling circuit uses low pressure low temperature refrigerant to decrease the temperature and pressure of the high temperature high pressure discharge refrigerant to improve efficiency and performance of the heat pump system. Additionally, a heat pump system including a multi-pass refrigerant circuit, such as a double pass heating circuit, can be configured such that (when operating in heating mode), the double pass heating circuit uses high pressure high temperature refrigerant to increase the temperature and pressure of the low temperature low pressure suction refrigerant to improve efficiency, performance, and lower minimum operating ambient temperature of the heat pump system.

In another aspect, a method performed at a refrigeration system is disclosed. The refrigeration system can include a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, a of one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchange, (iii) the internal heat exchange, and (iv) the multi-pass refrigerant circuit via the first set one or more valve, and a controller communicatively coupled to the first set one or more valves. The method includes operating the refrigeration system in a cooling mode in which the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor, and operating the refrigeration system in a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

In yet another aspect, a non-transitory, computer-readable storage medium including instructions executed at a refrigeration system is disclosed. The instructions of the non-transitory, computer-readable storage medium, when executed by one or more processors of a refrigeration system, cause the refrigeration system to operate in a cooling mode in which the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor, and operate in a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

The features and advantages described in the specification are not necessarily all inclusive and, in particular, certain additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes.

Having summarized the above example aspects, a brief description of the drawings will now be presented.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the various described embodiments, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

FIGS. 1A and 1B are block diagrams illustrating a refrigeration system operating in different modes, in accordance with some embodiments.

FIGS. 2A and 2B illustrate refrigerant flow through multi-pass refrigerant circuit 140 during cooling and heating modes, in accordance with some embodiments.

FIGS. 3A and 3B are block diagrams illustrating another embodiment of a refrigeration system operating in different modes, in accordance with some embodiments.

FIGS. 4A and 4B illustrate refrigerant flow through multi-pass refrigerant circuit 140 during cooling and heating modes, in accordance with some embodiments.

FIGS. 5A and 5B are block diagrams illustrating yet another embodiment of a refrigeration system operating in different modes, in accordance with some embodiments.

FIG. 6 is a flow diagram illustrating a method of operating a refrigeration system in one of a plurality of operating modes, in accordance with some embodiments.

FIG. 7 is a block diagram illustrating controller, in accordance with some embodiments.

DETAILED DESCRIPTION

The present disclosure describes various embodiments of refrigeration systems. The refrigeration systems can be heat pumps and/or part of an air conditioning system. In some embodiments, the refrigeration systems are a heating, ventilation, and air conditioning (HVAC) system or part thereof. The refrigeration systems can be used for mobile applications (e.g., vehicles, trucks, aircraft, etc.) and/or structures (e.g., buildings, rooms, etc.). In some embodiments, the refrigeration systems use multi-pass refrigeration circuits to improve the efficiency of the refrigeration system (e.g., improve the coefficient of performance (COP) in heat mode and AC mode of the refrigeration system). Use of the multi-pass refrigeration circuits also have the advantage of lower the minimum operating ambient temperature for heat mode, reducing the chance of compressor slugging, and reducing a size of accumulator that is needed during heat mode.

FIGS. 1A and 1B are block diagrams illustrating a refrigeration system operating in different modes, in accordance with some embodiments. In particular, FIG. 1A shows a refrigeration system 105 operating in a cooling mode 100 and FIG. 1B shows the refrigeration system 105 operating in a heating mode 150. The refrigeration system 105 includes a compressor 110, an accumulator 115, an external heat exchanger 120, an internal heat exchanger 180, a multi-pass refrigerant circuit 140, one or more valves (e.g., a first valve 170), and a plurality of refrigerant lines 190 fluidically coupling one or more components of the refrigeration system 105. For example, the plurality of refrigerant lines 190 can fluidically couple the compressor 110, the external heat exchanger 120, the internal heat exchanger 180, the multi-pass refrigerant circuit 140, and the one or more valves. In some embodiments, the refrigeration system 105 includes a controller 195 communicatively coupled to the compressor 110, the one or more valves, and/or other components of the refrigeration system (e.g., heat exchangers, fans 125, metering devices 130, accumulators 115, and/or one or more sensors 710 (e.g., temperature and/or pressure sensors) coupled to the components of the refrigeration system 105).

In various embodiments, the refrigeration system 105 includes one or more additional components not shown in FIGS. 1A-3B, such as blower fans, control circuitry, a user interface, air filters, refrigerant storage, and the like. In some embodiments, the refrigeration system 105 includes at least one user interface (e.g., a touch screen) and at least one sensor 710 (e.g., a thermostat). In some embodiments, the refrigeration system 105 includes at least one battery or power source and a battery monitoring system (also sometimes called a battery management module 719, as shown and described below in reference to FIG. 6). In some embodiments, the battery monitoring module 719 is communicatively coupled at least one sensor 710 (e.g., a current sensor). In some embodiments, the battery monitoring system 719 includes a part of a controller 195. In some embodiments, the controller 195 is electrically coupled to other components of the refrigeration system 105 (described below) to control operation of these components.

The one or more valves can include a first valve 170, a second valve 160, and/or a third valve 165. In some embodiments, the first valve 170 is a reversing valve (e.g., a 4-way reversing valve) that is configured to change a direction of refrigerant flow. The first valve can be a three-way, five-way, or six-way valve, etc. In some embodiments, the first valve 170 is a plurality of valves configured to change a direction of refrigerant flow. For example, as described below, the first valve 170 can change the flow of the refrigerant such that the refrigeration system 105 operates in cooling mode 100 or heating mode 150. In some embodiments, the first valve 170 is. In some embodiments, the first valve 170 is coupled to the controller 195 and receives instructions from the controller to change a direction of refrigerant flow (e.g., the first valve 170 is configured to selectively change, via the controller, a direction of refrigerant flow in accordance with changing between heating and cooling modes). In some embodiments, the first valve 170 is fluidically coupled to the compressor 110, the external heat exchanger 120, and/or the multi-pass refrigerant circuit 140. For example, as shown in FIG. 1A, the first valve 170 is (i) fluidically coupled to an outlet or an output of the compressor 110 via a first refrigerant line 190-1, (ii) fluidically coupled to the external heat exchanger 120 via a second refrigerant line 190-2, (iii) fluidically coupled to a fourth port of the multi-pass refrigerant circuit 140 via a sixth refrigerant line 190-6, and (iv) fluidically coupled to a fifth port of the multi-pass refrigerant circuit 140 via a seventh refrigerant line 190-7.

In some embodiments, the second valve 160 is a thermal expansion valve (TEV) or thermostatic expansion valve (TXV). In some embodiments, the second valve 160 is any kind of modulating metering device. The second valve 160 is configured to regulate the flow of refrigerant and/or regulate the superheat of the refrigerant. The second valve 160 can be fluidically coupled between the internal heat exchanger 180 and the multi-pass refrigerant circuit 140. As shown in FIGS. 1A and 1B, a fourth refrigerant line 190-4 fluidically couples a second port of the multi-pass refrigerant circuit 140 to the internal heat exchanger 180 and a fifth refrigerant line 190-5 fluidically couples the internal heat exchanger 180 to a third port of the multi-pass refrigerant circuit 140. The second valve 160 is fluidically coupled (i) along the fourth refrigerant line 190-4 between the second port of the multi-pass refrigerant circuit 140 and the internal heat exchanger 180 (e.g., between a first portion of the fourth refrigerant line 190-4a and a second portion of the fourth refrigerant line 190-4b), and (ii) along the fifth refrigerant line 190-5 between the internal heat exchanger 180 and the third port of the multi-pass refrigerant circuit 140 (e.g., between a first portion of the fifth refrigerant line 190-5a and a second portion of the fifth refrigerant line 190-5b). In some embodiments, the third valve 165 is a check valve (CK VLV) that is configured to configured to inhibit reverse flow of the refrigerant (e.g., allowing the refrigerant to flow in one direction). The third valve 165 is fluidically coupled between an inlet and an outlet of the second valve 160. For example, as shown in FIGS. 1A and 1B, the third valve 165 is fluidically coupled between the first portion of the fourth refrigerant line 190-4a and the second portion of the fourth refrigerant line 190-4b (e.g., before and/or after an inlet and outlet of the second valve 160). In this way, the third valve 165 directs the refrigerant either through the second valve 160 or allows the refrigerant to bypass the second valve 160 (depending on the operational mode).

The refrigeration system 105 can further include a metering device 130. The metering device 130 can a fixed metering device (e.g., a capillary tube or a fixed orifice). In some embodiments, the metering device 130 is a metering piston. In some embodiments, the metering device 130 is coupled between the external heat exchanger 120 and the multi-pass refrigerant circuit 140. For example, as shown in FIG. 1A, the metering device 130 is fluidically coupled between a first portion of the third refrigerant line 190-3a and a second portion of the third refrigerant line 190-3b (e.g., between the external heat exchanger 120 and a first port of the multi-pass refrigerant circuit 140, which are fluidically coupled via a third refrigerant line 190-3). If a multi-pass refrigerant circuit 140 is not coupled between the external heat exchanger 120 and the internal heat exchanger 180, the metering device 130 can be fluidically coupled between the external heat exchanger 120 and the internal heat exchanger 180 (as shown and described below in reference to FIGS. 3A and 3B).

The compressor 110 is fluidically coupled to a sixth port of the multi-pass refrigerant circuit 140 via an eighth refrigerant line 190-8. In some embodiments, an accumulator 115 is coupled to an inlet of the compressor 110. In some embodiments, the compressor 110 is an electrically driven compressor. In some embodiments, the eighth refrigerant line 190-8 fluidically couples the sixth port of the multi-pass refrigerant circuit 140 and the accumulator 115. In some embodiments, the compressor 110 is a refrigeration compressor (e.g., piston (reciprocating) compressors, screw compressors, scroll (spiral) compressors, open compressors, hermetic compressors, semi-hermetic compressors, etc.). In some embodiments, the compressor 110 is a vapor injection scroll compressor or a variable speed compressor. In some embodiments, the refrigeration system 105 includes an electric power source for powering the compressor 110, the controller 195, the fan 125, and/or other components of the system. In some embodiments, the system is configured to operate independently (e.g., independent of an operating state of a vehicle (e.g., does not require the vehicle's engine to be on)). In some embodiments, the refrigeration system 105 includes a plurality of compressors.

In some embodiments, the refrigeration system 105 includes a fan 125 coupled with the external heat exchanger 120. The multi-pass refrigerant circuit 140 can be a double pass heat exchanger.

When the refrigeration system 105 operates in a cooling mode, the multi-pass refrigerant circuit 140 uses low pressure low temperature refrigerant to decrease the temperature and pressure of the high temperature high pressure discharge refrigerant to improve efficiency and performance. The refrigerant flow is represented by filled chevron patterns and unfilled chevron patterns. The filled chevron patterns represent the discharge, high temperature, and/or high-pressure flow. The unfilled chevron patterns represent the suction line, low temperature, and/or low-pressure flow. In some embodiments, while operating in the cooling mode, the refrigeration system 105 (i) causes a refrigerant to flow from the compressor 110 to the external heat exchanger 120 via the first valve 170 (e.g., refrigerant flows from the compressor 110 to the first valve 170 and from the first valve 170 to the external heat exchanger 120), (ii) causes the refrigerant to flow from the external heat exchanger 120 to the internal heat exchanger 180 via the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from external heat exchanger 120 through the first and second ports of the multi-pass refrigerate circuit 140 to the internal heat exchanger 180), and (iii) causes the refrigerant to flow from the internal heat exchanger 180 to the compressor 110 via the multi-pass refrigerant circuit 140 and the first valve 170 (e.g., refrigerant flows from the internal heat exchanger 180 through the third and fourth ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110).

As further shown in FIG. 1A, the refrigeration system 105, operating in cooling mode, causes the refrigerant to flow through one or more of the metering device 130, the second valve 160, the third valve 165, and/or the accumulator 115. For example, the metering device 130 operates in a bypass mode and the refrigerant flows from the external heat exchanger 120, through the metering device 130, through the first and second ports of the multi-pass refrigerant circuit 140 and through the second valve 160 to the internal heat exchanger 180.

Turning to 1B, the refrigeration system 105 is shown operating in a heating mode 150. When the refrigeration system 105 operates in a heating mode, the multi-pass refrigerant circuit 140 uses high pressure high temperature refrigerant to increase the temperature and pressure of the low temperature low pressure suction refrigerant to improve efficiency, performance, and lower minimum operating ambient temperature. In heating mode, the flow of the refrigerant is changed as represented by the filled and unfilled chevron patterns. In particular, when operating in the heating mode, the refrigeration system 105 (i) causes the refrigerant to flow from the compressor 110 to the internal heat exchanger 180 via the first valve 170 and the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from the compressor 110 to the first valve 170 through the fourth and third ports of the multi-pass refrigerant circuit 140 and to the internal heat exchanger 180), (ii) causes the refrigerant to flow from the internal heat exchanger 180 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from the internal heat exchanger 180 through the second and first ports of the multi-pass refrigerant circuit 140 to the external heat exchanger 120), and (iii) causes the refrigerant to flow from the external heat exchanger 120 to the compressor 110 via the first valve 170 and the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from the external heat exchanger 120 to the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 and to the compressor 110).

As further shown in FIG. 1B, the refrigeration system 105, operating in heating mode, causes the refrigerant to flow through one or more of the metering device 130, the second valve 160, the third valve 165, and/or the accumulator 115. For example, the refrigerant flows through the third valve 165 (e.g., bypassing the second valve 160) through the second and first ports of the multi-pass refrigerant circuit 140 to the metering device 130, which acts as an office tube, and to the external heat exchanger 120.

FIGS. 2A and 2B illustrate refrigerant flow through multi-pass refrigerant circuit 140 during cooling and heating modes, in accordance with some embodiments. In particular, FIG. 2A shows a first cross section 200 of the multi-pass refrigerant circuit 140 while the refrigerant system 105 operates in cooling mode 100 and FIG. 2B shows a second cross section 250 of the multi-pass refrigerant circuit 140 while the refrigerant system 105 operates in heating mode 150.

In FIG. 2A, a compressor 110 (FIGS. 1A-1B) directs discharge to a first valve 170 via a first refrigerant line 190-1; the first valve 170 directs the refrigerant from the compressor 110 to an external heat exchanger 120 via a second refrigerant line 190-2; the refrigerant passes through the external heat exchanger 120 before returning to the multi-pass refrigerant circuit 140 (e.g., via a third refrigerant line 190-3; FIGS. 1A-1B); the multi-pass refrigerant circuit 140 directs the refrigerant to an internal heat exchanger 180 (e.g., via a fourth refrigerant line 190-4; FIGS. 1A-1B); the refrigerant passes through the internal heat exchanger 180 before returning to the multi-pass refrigerant circuit 140 (e.g., via a fifth refrigerant line 190-5; FIGS. 1A-1B); the multi-pass refrigerant circuit 140 directs the refrigerant to the first valve 170 via a sixth refrigerant line 190-6; the first valve 170 returns the refrigerant back to the multi-pass refrigerant circuit 140 via a seventh refrigerant line 190-7; and the multi-pass refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via an eighth refrigerant line 190-8; FIGS. 1A-1B).

The refrigerant is discharged from the compressor 110 at a high temperature and flows, at the high temperature, to the external heat exchanger 120 (e.g., via the first valve 170 and the first and second refrigerant lines 190-1 and 190-2). As the high temperature refrigerant passes through the external heat exchanger 120 to the multi-pass refrigerant circuit 140 (e.g., via the third refrigerant line 190-3), its temperature decreases from the high temperature to a medium-high temperature (where the medium-high temperature is lower than the high temperature). The multi-pass refrigerant circuit 140 directs the medium-high temperature refrigerant to the internal heat exchanger 180 (e.g., via the fourth refrigerant line 190-4). As the medium-high temperature refrigerant passes through the internal heat exchanger 180 back to the multi-pass refrigerant circuit 140 (e.g., via the fifth refrigerant line 190-5), its temperature further decreases from the medium-high temperature to a low temperature (where the low temperature is lower than the medium-high temperature and lower than the medium-low temperature refrigerant that is returned to the compressor 110). The multi-pass refrigerant circuit 140 directs the low temperature refrigerant to the first valve 170 (e.g., via the sixth refrigerant line 190-6), which returns the refrigerant to the multi-pass refrigerant circuit 140 (e.g., via the seventh refrigerant line 190-7). As the low temperature refrigerant flows through the multi-pass refrigerant circuit 140, its temperature increases from the low temperature to a medium-low temperature. The multi-pass refrigerant circuit 140 returns the medium-low temperature refrigerant to the compressor 110 (e.g., via the eighth refrigerant line 190-8).

In FIG. 2B, the compressor 110 directs discharge to the first valve 170 via the first refrigerant line 190-1; the first valve 170 directs the refrigerant to the multi-pass refrigerant circuit 140 via the sixth refrigerant line 190-6; the multi-pass refrigerant circuit 140 directs the refrigerant to an internal heat exchanger 180 (e.g., via the fifth refrigerant line 190-5); the refrigerant passes through the internal heat exchanger 180 before returning to the multi-pass refrigerant circuit 140 (e.g., via the fourth refrigerant line 190-4); the multi-pass refrigerant circuit 140 directs the refrigerant to the external heat exchanger 120 (e.g., via the third refrigerant line 190-3); the refrigerant passes through the external heat exchanger 120 towards the first valve 170 via the second refrigerant line 190-2; the first valve 170 directs the refrigerant to the multi-pass refrigerant circuit 140 via the seventh refrigerant line 190-7; and the multi-pass refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via the eighth refrigerant line 190-8).

The refrigerant is discharged from the compressor 110 at a high temperature and flows, at the high temperature, to the multi-pass refrigerant circuit 140 (e.g., via the first valve 170 first and sixth refrigerant lines 190-1 and 190-6). The multi-pass refrigerant circuit 140 directs the high temperature refrigerant to the internal heat exchanger 180 (e.g., via the fifth refrigerant line 190-5). As the high temperature refrigerant passes through the internal heat exchanger 180 back to the multi-pass refrigerant circuit 140 (e.g., via the fourth refrigerant line 190-4), its temperature decreases from the high temperature to a medium-high temperature. The multi-pass refrigerant circuit 140 directs the medium-high temperature refrigerant to the external heat exchanger 120 (e.g., via the third refrigerant line 190-3). As the medium-high temperature refrigerant passes through the external heat exchanger 120 to the first valve 170 (e.g., via the second refrigerant line 190-2), its temperature decreases from the medium-high temperature to a low temperature. As the low refrigerant passes through the first valve 170 and through the multi-pass refrigerant circuit 140 (e.g., via the seventh refrigerant line 190-7), its temperature increases from the low temperature to a medium-low temperature. The multi-pass refrigerant circuit 140 then returns the medium-low temperature refrigerant to the compressor 110 (e.g., via the eighth refrigerant line 190-8).

FIGS. 3A and 3B are block diagrams illustrating another embodiment of a refrigeration system operating in different modes, in accordance with some embodiments. The refrigeration system 305 includes similar components to those described above in reference to FIGS. 1A and 1B. In particular, the refrigeration system 305 repositions one or more components such as the multi-pass refrigerant circuit 140 and the metering device 130. For example, in the refrigeration system 305, an outlet of the compressor 110 is fluidically coupled to a first port of the multi-pass refrigerant circuit 140 via first refrigerant line 390-1, a second port of the multi-pass refrigerant circuit 140 is fluidically coupled to the first valve 170 via a second refrigerant line 390-2, the first valve 170 is fluidically coupled to the external heat exchanger 120 via a third refrigerant line 390-3, the external heat exchanger 120 is fluidically coupled to the internal heat exchanger 180 via a fourth refrigerant line 390-4, the internal heat exchanger 180 is fluidically coupled to a third port of the multi-pass refrigerant circuit via a fifth refrigerant line 390-5, a fourth port of the multi-pass refrigerant circuit 140 is fluidically coupled to the first valve 170 via a sixth refrigerant line 390-6, the first valve 170 is fluidically coupled to a fifth port of the multi-pass refrigerant circuit 140 via a seventh refrigerant line 390-7, and a sixth port of the multi-pass refrigerant circuit 140 is fluidically coupled to an inlet of the compressor 110 via an eighth refrigerant line 390-8.

In some embodiments, the second valve 160 is coupled between the external heat exchanger 120 and the internal heat exchanger 180 and the internal heat exchanger 180 and the multi-pass refrigerant circuit 140. For example, as shown in FIGS. 3A and 3B, the second valve 160 is fluidically coupled (i) along the fourth refrigerant line 190-4 between the external heat exchanger 120 and the internal heat exchanger 180 (e.g., between first portion of the fourth refrigerant line 190-4a (or second portion of the fourth refrigerant line 190-4b) and third portion of the fourth refrigerant lines 190-4c), and (ii) along the fifth refrigerant line 190-5 between the first port of the multi-pass refrigerant circuit 140 and the internal heat exchanger 180 (e.g., between first portion of the fifth refrigerant line 190-5a and second portion of the fifth refrigerant line 190-5b). The third valve 165 is fluidically coupled between an inlet and an outlet of the second valve 160. For example, as shown in FIGS. 3A and 3B, the third valve 165 is fluidically coupled between a first portion of the fourth refrigerant line 190-4a (or a second portion of the fourth refrigerant line 190-4b) and a third portion of the fourth refrigerant lines 190-4c) and the third portion of the fourth refrigerant line 190-4c (e.g., before and/or after an inlet and outlet of the second valve 160).

Similarly, in some embodiments, the metering device 130 is coupled between the external heat exchanger 120 and the internal heat exchanger 180. For example, as shown in FIGS. 3A and 3B, the metering device 130 is fluidically coupled between a first portion of the fourth refrigerant line 190-4a and the second portion of the fourth refrigerant line 190-4b (or the third portion of the fourth refrigerant line 190-4c).

While operating in the cooling mode 300, the refrigeration system 305 (i) causes a refrigerant to flow from the compressor 110 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140 and the first valve 170 (e.g., refrigerant flows from the compressor 110 through the first and second ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 to the external heat exchanger 120), (ii) causes the refrigerant to flow from the external heat exchanger 120 to the internal heat exchanger 180, and (iii) causes the refrigerant to flow from the internal heat exchanger 180 to the compressor 110 via the multi-pass refrigerant circuit 140 and the first valve 170 (e.g., refrigerant flows from the internal heat exchanger 180 through the third and fourth ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110).

As further shown in FIG. 3A, the refrigeration system 305, operating in cooling mode, causes the refrigerant to flow through one or more of the metering device 130, the second valve 160, the third valve 165, and/or the accumulator 115. For example, the refrigerant can flow from the external heat exchanger 120 through the metering device 130 (e.g., operating in a bypass mode) and/or through the second valve 160 to the internal heat exchanger 180.

Turning to 3B, the refrigeration system 305 is shown operating in a heating mode. In particular, when operating in the heating mode 350, the refrigeration system 305 (i) causes the refrigerant to flow from the compressor 110 to the internal heat exchanger 180 via the multi-pass refrigerant circuit 140 and the first valves 170 (e.g., the refrigerant flows from the compressor 110 through the first and second ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fourth and third ports of the multi-pass refrigerant circuit 140 to the internal heat exchanger 180), (ii) causes the refrigerant to flow from the internal heat exchanger 180 to the external heat exchanger 120, and (iii) causes the refrigerant to flow from the external heat exchanger 120 to the compressor 110 via the first valve 170 and the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from external heat exchanger 120 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110).

As further shown in FIG. 3B, the refrigeration system 105, operating in heating mode, causes the refrigerant to flow through one or more of the metering device 130, the second valve 160, the third valve 165, and/or the accumulator 115. For example, the refrigerant flows through the third valve 165 (e.g., bypassing the second valve 160) to the metering device 130, which acts as an office tube, and to the external heat exchanger 120.

FIGS. 4A and 4B illustrate refrigerant flow through multi-pass refrigerant circuit 140 during cooling and heating modes, in accordance with some embodiments. In particular, FIG. 4A shows a first cross section 400 of the multi-pass refrigerant circuit 140 while the refrigerant system 305 operates in cooling mode 300 and FIG. 4B shows a second cross section 450 of the multi-pass refrigerant circuit 140 while the refrigerant system 305 operates in heating mode 350.

In FIG. 4A, a compressor 110 (FIGS. 3A-3B) directs discharge to a multi- pass refrigerant circuit 140 via a first refrigerant line 390-1; the multi-pass refrigerant circuit 140 directs the refrigerant to the first valve 170 via a second refrigerant line 390-2; the first valve 170 directs the refrigerant to an externa heat exchanger 120 via a third refrigerant line 390-3; the refrigerant passes through the external heat exchanger 120 toward the internal heat exchanger 180 (e.g., via a fourth refrigerant line 390-4; FIGS. 3A-3B); the refrigerant passes through the internal heat exchanger 180 before returning to the multi-pass refrigerant circuit 140 (e.g., via a fifth refrigerant line 390-5; FIGS. 3A-3B); the multi-pass refrigerant circuit 140 directs the refrigerant to the first valve 170 via a sixth refrigerant line 390-6; the first valve 170 returns the refrigerant back to the multi-pass refrigerant circuit 140 via a seventh refrigerant line 390-7; and the multi-pass refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via an eighth refrigerant line 390-8; FIGS. 3A-3B).

The refrigerant is discharged from the compressor 110 at a high temperature and flows, at the high temperature, to the multi-pass refrigerant circuit 140 (e.g., via a first refrigerant line 390-1). The multi-pass refrigerant circuit 140 directs the high temperature refrigerant to the first valve 170 (e.g., via a second refrigerant line 390-2), and the first valve 170 directs the high temperature refrigerant to the external heat exchanger 120 (e.g., via a third refrigerant line 390-3). As the high temperature refrigerant passes through the external heat exchanger 120 to the internal heat exchanger 180 (e.g., via the fourth refrigerant line 390-4) and from the internal heat exchanger 180 to the multi-pass refrigerant circuit 140 (e.g., via a fifth refrigerant line 390-5), its temperature decreases from the high temperature to a low temperature. The multi-pass refrigerant circuit 140 directs the low temperature refrigerant to the first valve 170 (e.g., via the sixth refrigerant line 390-6), which returns the refrigerant to the multi-pass refrigerant circuit 140 (e.g., via the seventh refrigerant line 390-7). As the low temperature refrigerant passes through the multi-pass refrigerant circuit 140, its temperature increases from the low temperature to a medium-low temperature. The multi-pass refrigerant circuit 140 then returns the medium-low temperature refrigerant to the compressor 110 (e.g., via the eighth refrigerant line 390-8).

In FIG. 4B, the compressor 110 directs discharge to a multi-pass refrigerant circuit 140 via a first refrigerant line 390-1; the multi-pass refrigerant circuit 140 directs the refrigerant to the first valve 170 via a second refrigerant line 390-2; the first valve 170 directs the refrigerant back to the multi-pass refrigerant circuit 140 via the sixth refrigerant line 390-6; the multi-pass refrigerant circuit 140 directs the refrigerant to the internal heat exchanger 180 (e.g., via the fifth refrigerant line 390-5); the refrigerant passes through the internal heat exchanger 180 toward the external heat exchanger 120 (e.g., via the fourth refrigerant line 390-4); the refrigerant passes through the external heat exchanger 120 toward the first valve 170 (e.g., via the third refrigerant line 390-3); the first valve 170 returns the refrigerant back to the multi-pass refrigerant circuit 140 via a seventh refrigerant line 390-7; and the multi-pass refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via the eighth refrigerant line 390-8).

The refrigerant is discharged from the compressor 110 at a high temperature and flows, at the high temperature, to the multi-pass refrigerant circuit 140 (e.g., via the first refrigerant line 390-1). The multi-pass refrigerant circuit 140 directs the high temperature refrigerant to the first valve 170 (e.g., via the second refrigerant line 390-2). As the high temperature refrigerant passes through the first valve 170 and is directed back to and through the multi-pass refrigerant circuit 140 (e.g., via the sixth refrigerant line 390-6), its temperature decreases from the high temperature to a medium-high temperature. The multi-pass refrigerant circuit 140 directs the medium-high temperature refrigerant to the internal heat exchanger 180 (e.g., via the fifth refrigerant line 390-5). As the medium-high temperature refrigerant passes through the internal heat exchanger 180 to the external heat exchanger 120 (e.g., via the fourth refrigerant line 390-4) and through the external heat exchanger 120 toward the first valve 170 (e.g., via the third refrigerant line 390-3), its temperature decreases from the medium-high temperature to a low temperature. As the low temperature refrigerant passes through the first valve 170 to and through the multi-pass refrigerant circuit 140 (e.g., via the seventh refrigerant line 390-7), its temperature increases from the low temperature to a medium-low temperature. The multi-pass refrigerant circuit 140 then returns the medium-low temperature refrigerant to the compressor 110 (e.g., via the eighth refrigerant line 390-8).

FIGS. 5A and 5B are block diagrams illustrating yet another embodiment of a refrigeration system operating in different modes, in accordance with some embodiments. The refrigeration system 505 includes similar components to those described above in reference to FIGS. 1A and 1B; however, the refrigeration system 505 removes the metering device 130 and the third valve 165. In particular, the refrigeration system 505 includes a compressor 110, an accumulator 115, an external heat exchanger 120, an internal heat exchanger 180, a multi-pass refrigerant circuit 140, one or more valves (e.g., a first valve 170), and a plurality of refrigerant lines 190 and 590 fluidically coupling one or more components of the refrigeration system 105, as well as a controller 195 and/or one or more sensors 710 coupled with one or more components of the refrigeration system 505. The refrigeration system 505 further includes an additional fan 126 or blower adjacent to the internal heat exchanger 180. The refrigeration system 505 includes, and operates, in the same modes described above in reference to the refrigeration system 105 (e.g., cooling mode 500 and hearing mode 550). In particular, the refrigerant flow through multi-pass refrigerant circuit 140 for the respective modes is analogous to the flow described above in reference to FIGS. 1A and 1B. The additional benefits provide by refrigeration system 505 include reduced costs, simplified system, and smaller form factor.

FIG. 6 is a flow diagram illustrating a method 600 of operating a refrigeration system in one of a plurality of operating modes, in accordance with some embodiments. In some embodiments, the method 600 is performed by a refrigeration system (e.g., the refrigeration system 105 and 305), or a component of the refrigeration system, such as the controller 195. In some implementations, the method 600 is governed by instructions that are stored in a non-transitory computer-readable storage medium (e.g., the memory 708; FIG. 6) and the instructions are executed by one or more processors of the electronic device (e.g., the processors 702; FIG. 6). For convenience, the method 600 is described below as being performed by refrigeration systems 105 and 305.

The method 600 includes operating (610) the refrigeration systems 105, 305 or 505 in a cooling mode. In cooling mode, a multi-pass refrigeration circuit 140 (FIGS. 1A-4B) uses (615) a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor.

For the refrigeration system 105 described above in reference to FIGS. 1A and 1B, operating in cooling mode includes causing a refrigerant to flow from the compressor 110 to the external heat exchanger 120 via the one or more valves (e.g., first valve 170), causing the refrigerant to flow from the external heat exchanger 120 to the internal heat exchanger 180 via the multi-pass refrigerant circuit 140, and causing the refrigerant to flow from the internal heat exchanger 180 to the compressor 110 via the multi-pass refrigerant circuit 140 and the one or more valves. In particular, the refrigerant is caused to (i) flow from the compressor 110 to first valve 170 and to the external heat exchanger 120, (ii) flow from external heat exchanger 120 through the first and second ports of the multi-pass refrigerant circuit 140 to the internal heat exchanger 180 (e.g., through the metering device 130 and the second valve 160), and (iii) flow from the internal heat exchanger 180 (through the second valve 160) to the third and fourth ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110.

For the refrigeration system 305 described above in reference to FIGS. 3A and 3B, operating in cooling mode includes causing a refrigerant to flow from the compressor 110 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140 and the one or more valves (e.g., first valve 170), causing the refrigerant to flow from the external heat exchanger 120 to the internal heat exchanger 180, and causing the refrigerant to flow from the internal heat exchanger 180 to the compressor 110 via the multi-pass refrigerant circuit 140 and the one or more valves. In particular, the refrigerant is caused to (i) flow from the compressor 110 through the first and second ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 to the external heat exchanger, (ii) flow from the external heat exchanger 120 to the internal heat exchanger 180 (e.g., through the metering device 130 and the second valve 160), and (iii) flow from the internal heat exchanger 180 through the third and fourth ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110.

The method 600 includes operating (620) the refrigeration systems 105, 305, or 505 in a heating mode. In heating mode, a multi-pass refrigeration circuit 140 uses (625) the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

For the refrigeration system 105 described above in reference to FIGS. 1A and 1B, operating in heating mode includes causing the refrigerant to flow from the compressor 110 to the internal heat exchanger 180 via the one or more valves (e.g., first valve 170) and the multi-pass refrigerant circuit 140, causing the refrigerant to flow from the internal heat exchanger 180 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140, causing the refrigerant to flow from the external heat exchanger 120 to the compressor 110 via the one or more valves and the multi-pass refrigerant circuit 140. In particular, the refrigerant is caused to (i) flow from the compressor 110 to the first valve 170 through the fourth and third ports of the multi-pass refrigerant circuit 140 and (through the second valve 160) to the internal heat exchanger 180, (ii) flow from internal heat exchanger 180 through the third valve 165, the second and first ports of the multi-pass refrigerant circuit 140, and metering device 130 to the external heat exchanger 120, and (iii) flow from the external heat exchanger 120 to the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 and to the compressor 110.

For the refrigeration system 305 described above in reference to FIGS. 3A and 3B, operating in heating mode includes causing the refrigerant to flow from the compressor 110 to the internal heat exchanger 180 via the multi-pass refrigerant circuit 140 and the one or more valves (e.g., first valve 170), causing the refrigerant to flow from the internal heat exchanger 180 to the external heat exchanger 120, and causing the refrigerant to flow from the external heat exchanger 120 to the compressor 110 via the one or more valves and the multi-pass refrigerant circuit 140. In particular, the refrigerant is caused to (i) flow from the compressor 110 through the first and second ports of the multi-pass refrigerant circuit 140 to the first valve 170 and from the first valve 170 through the fourth and third ports of the multi-pass refrigerant circuit 140 (through the second valve 160) to the internal heat exchanger 180, (ii) flow from the internal heat exchanger 180 (e.g., through the third valve 165 and the metering device 130) to the external heat exchanger 120, and (iii) flow from external heat exchanger 120 to the first valve 170 and from the first valve 170 through the fifth and sixth ports of the multi-pass refrigerant circuit 140 to the compressor 110.

FIG. 7 is a block diagram illustrating controller 195 in accordance with some embodiments. In some embodiments, the controller 195 is, or includes, control circuitry for operating the refrigeration systems 105 and 305. In some embodiments, the controller 195 includes one or more processors 702, one or more communication interfaces 704, memory 708, and one or more communication buses 706 for interconnecting these components (sometimes called a chipset). In accordance with some embodiments, the controller 195 is coupled to one or more sensors 710 (e.g., temperature sensors, pressure sensors, current sensors, etc.) and a power source 712 (e.g., a battery or electrically-driven motor). In some embodiments, the memory 708 includes high-speed random-access memory, such as DRAM, SRAM, DDR RAM, or other random-access solid-state memory devices; and, optionally, includes non-volatile memory, such as one or more magnetic disk storage devices, one or more optical disk storage devices, one or more flash memory devices, or one or more other non-volatile solid state storage devices. The memory 708, optionally, includes one or more storage devices remotely located from the one or more processors 702. The memory 708, or alternatively the non-volatile memory within the memory 708, includes a non-transitory computer readable storage medium. In some embodiments, the memory 708, or the non-transitory computer readable storage medium of the memory 708, stores the following programs, modules, and data structures, or a subset or superset thereof:

• • operating logic 714 including procedures for handling various basic system services and for performing hardware dependent tasks;
  • communication module 716 for communicatively-connecting the controller 195 to other computing devices (e.g., vehicular control system or client device) via one or more networks (e.g., the Internet);
  • interface module 717 for presenting information to a user and detecting user input(s) (e.g., in conjunction with communication interface(s) 704);
  • state module 718 for setting and/or adjusting an operating state of the conditioning system (e.g., heating or cooling mode)
  • battery monitoring module 719 for distributing to and/or monitoring power of one or more components of the refrigeration system; and
  • database 720 storing data for use in governing operation of a refrigeration system (e.g., the refrigeration systems 105 and 305), including but not limited to:
    • sensor information 722 storing information regarding one or more sensors associated with the conditioning system (e.g., temperature data, pressure data, and/or current data);
    • component settings 724 storing information regarding one or more components of the conditioning system (e.g., operational settings, such as speed and power); and
    • user information 726 storing information regarding user preferences, settings, history, etc.

Each of the above identified elements may be stored in one or more of the previously mentioned memory devices, and corresponds to a set of instructions for performing a function described above. The above identified modules or programs (i.e., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. In some embodiments, the memory 708, optionally, stores a subset of the modules and data structures identified above. Furthermore, the memory 708, optionally, stores additional modules and data structures not described above, such as a vehicle module for interfacing between the vehicle and the conditioning system.

Although some of various drawings illustrate a number of logical stages in a particular order, stages that are not order dependent may be reordered and other stages may be combined or broken out. While some reordering or other groupings are specifically mentioned, others will be obvious to those of ordinary skill in the art after reading this disclosure, so the ordering and groupings presented herein are not an exhaustive list of alternatives.

Having thus described system-block diagrams and then example refrigeration systems, attention will now be directed to certain example embodiments.

Example Aspects

A few example aspects will now be briefly described.

(A1) In accordance with some embodiments, a refrigeration system is disclosed. The refrigeration system includes a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, (iv) the multi-pass refrigerant circuit, and (v) the one or more valves, and a controller communicatively coupled to the one or more valves. The controller is configured to operate the refrigeration system in a plurality of modes, including a cooling mode and a heating mode. In the cooling mode, the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor. In the heating mode, the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

(A2) In some embodiments of A1, the refrigeration system includes a metering device (e.g., a metering piston) fluidically coupled between the external heat exchanger and the internal heat exchanger. In some embodiments, the metering device is coupled between the external heat exchanger and the multi-pass circuit (if there is a multi-pass circuit between the external heat exchanger and the internal heat exchanger).

(A3) In some embodiments of A1-A2, the refrigeration system further includes a second valve (e.g., a thermostatic expansion valve) fluidically coupled between the internal heat exchanger and/or the multi-pass circuit.

(A4) In some embodiments of A3, the refrigeration system further includes a third valve (e.g., a check valve) fluidically coupled between an inlet and an outlet of the second valve.

(A5) In some embodiments of A4, the third valve includes one or more check valves configured to inhibit reverse flow of the refrigerant.

(A6) In some embodiments of A1-A5, the refrigeration system further include an accumulator fluidically coupled between the compressor and the multi-pass circuit. In some embodiments, the accumulator is coupled to the compressor.

(A7) In some embodiments of A1-A6, the refrigeration system further includes a fan coupled with the external heat exchanger.

(A8) In some embodiments of A1-A7, the one or more valves is a four-way reversing valve configured to selectively change, via the controller, a direction of refrigerant flow in accordance with changing between heating and cooling modes.

(A9) In some embodiments of A1-A8, the plurality of refrigerant lines includes a first refrigerant line fluidically coupling an output of the compressor to the one or more valves, a second refrigerant line fluidically coupling the one or more valves to the external heat exchanger, a third refrigerant line fluidically coupling the external heat exchanger to a first port of the multi-pass circuit, a fourth refrigerant line fluidically coupling a second port of the multi-pass circuit to the internal heat exchanger, a fifth refrigerant line fluidically coupling the internal heat exchanger to a third port of the multi-pass circuit, a sixth refrigerant line fluidically coupling a fourth port of the multi-pass circuit to the one or more valves, a seventh refrigerant line fluidically coupling the one or more valves to a fifth port of the multi-pass circuit, and an eighth refrigerant line fluidically coupling a sixth port of the multi-pass circuit to an inlet of the compressor.

(A9.5) In some embodiments of A9, operating in the cooling mode includes causing a refrigerant to flow from the compressor to the external heat exchanger via the one or more valves, causing the refrigerant to flow from the external heat exchanger to the internal heat exchanger via the multi-pass circuit, and causing the refrigerant to flow from the internal heat exchanger to the compressor via the multi-pass circuit and the one or more valves. The refrigerant is caused to flow from the compressor to the one or more valves and to the external heat exchanger, from external heat exchanger through the first and second ports of the multi-pass circuit to the internal heat exchanger, and from the internal heat exchanger to the third and fourth ports of the multi-pass circuit to the one or more valves and from the one or more valves through the fifth and sixth ports of the multi-pass circuit to the compressor.

(A10) In some embodiments of A8-A9.5, operating in the heating mode includes causing the refrigerant to flow from the compressor to the internal heat exchanger via the one or more valves and the multi-pass circuit, causing the refrigerant to flow from the internal heat exchanger to the external heat exchanger via the multi-pass circuit, and causing the refrigerant to flow from the external heat exchanger to the compressor via the one or more valves and the multi-pass circuit. The refrigerant is caused to flow from the compressor to the one or more valves through the fourth and third ports of the multi-pass circuit and to the internal heat exchanger, the refrigerant is caused to flow from internal heat exchanger through the second and first ports of the multi-pass circuit to the external heat exchanger, and from the external heat exchanger to the one or more valves through the fifth and sixth ports of the multi-pass circuit and to the compressor.

(A11) In some embodiments of A1-A7, the plurality of refrigerant lines includes a first refrigerant line fluidically coupling an outlet of the compressor to a first port of the multi-pass circuit, a second refrigerant line fluidically coupling a second port of the multi-pass circuit to the one or more valves, a third refrigerant line fluidically coupling the one or more valves to the external heat exchanger, a fourth refrigerant line fluidically coupling the external heat exchanger to the internal heat exchanger, a fifth refrigerant line fluidically coupling the internal heat exchanger to a third port of the multi-pass circuit, a sixth refrigerant line fluidically coupling a fourth port of the multi-pass circuit to the one or more valves, a seventh refrigerant line fluidically coupling the one or more valves to a fifth port of the multi-pass circuit, and an eighth refrigerant line fluidically coupling a sixth port of the multi-pass circuit to an inlet of the compressor.

(A12) In some embodiments of A11, operating in the cooling mode includes causing a refrigerant to flow from the compressor to the external heat exchanger via the multi-pass circuit and the one or more valves, causing the refrigerant to flow from the external heat exchanger to the internal heat exchanger, and causing the refrigerant to flow from the internal heat exchanger to the compressor via the multi-pass circuit and the one or more valves. The refrigerant is caused to flow from the compressor through the first and second ports of the multi-pass circuit to the one or more valves and from the one or more valves to the external heat exchanger, from the external heat exchanger to the internal heat exchanger, and from the internal heat exchanger through the third and fourth ports of the multi-pass circuit to the one or more valves and from the one or more valves through the fifth and sixth ports of the multi-pass circuit to the compressor.

(A13) In some embodiments of A11-A12, operating in the heating mode includes causing the refrigerant to flow from the compressor to the internal heat exchanger via the multi-pass circuit and the one or more valves, causing the refrigerant to flow from the internal heat exchanger to the external heat exchanger, and causing the refrigerant to flow from the external heat exchanger to the compressor via the one or more valves and the multi-pass circuit. The refrigerant is caused to flow from the compressor through the first and second ports of the multi-pass circuit to the one or more valves and from the one or more valves through the fourth and third ports of the multi-pass circuit to the internal heat exchanger, from the internal heat exchanger to the external heat exchanger, and from external heat exchanger to the one or more valves and from the one or more valves through the fifth and sixth ports of the multi-pass circuit to the compressor.

(A14) In some embodiments of A1-A13, the refrigeration system is a heating, ventilation and air conditioning (HVAC) system.

(A15) In some embodiments of A1-A14, the compressor is an electrically-driven compressor.

(B1) In accordance with some embodiments, a method performed at a refrigeration system is disclosed. The method is performed at a refrigeration system including a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, a of one or more valves, a plurality of refrigerant lines fluidically coupling (i) the compressor, (ii) the external heat exchange, (iii) the internal heat exchange, and (iv) the multi-pass refrigerant circuit via the first set one or more valve, and a controller communicatively coupled to the first set one or more valves. The method include operating the refrigeration system in a cooling mode and operating the refrigeration system in a heating mode. In the cooling mode, the multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor. In the heating mode, the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

(B2) In some embodiments of B1, the refrigeration system is configured in accordance with and configured to perform the operations of the refrigeration system of A2-A15.

(C1) In accordance with some embodiments, a non-transitory, computer-readable storage medium is disclosed. T non-transitory, computer-readable storage medium includes instructions that, when executed by one or more processors of a refrigeration system, cause the refrigeration system to operate in a cooling mode and operate in a heating mode. When the refrigeration system is caused to operate in the cooling mode, a multi-pass refrigerant circuit uses a refrigerant flow from the internal heat exchanger to decrease a temperature and a pressure of a refrigerant flow from the compressor. When the refrigeration system is caused to operate in the heating mode, the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase a temperature and a pressure of a refrigerant flow from the external heat exchanger.

(C2) In some embodiments of C1, the refrigeration system is configured in accordance with and configured to perform the operations of the refrigeration system of A1-A15.

It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

For example, a first valve could be termed a second valve, and, similarly, a second valve could be termed a first valve, without departing from the scope of the various described embodiments. The first valve and the second valve are both valves, but they are not the same valve unless explicitly stated.

The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

As used herein, the term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting” or “in accordance with a determination that,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event]” or “in accordance with a determination that [a stated condition or event] is detected,” depending on the context.

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen in order to best explain the principles underlying the claims and their practical applications, to thereby enable others skilled in the art to best use the embodiments with various modifications as are suited to the particular uses contemplated.