Heat pump with multi-path refrigerant circuit

Abstract

Various embodiments described herein include methods, devices, and systems for cooling or heating an area (e.g., a vehicle, a room, etc.). In one aspect, a refrigeration system includes a compressor, an external heat exchanger (HX), an internal HX, a multi-path refrigerant circuit, one or more valves, and a plurality of refrigerant lines fluidly coupling (i) the compressor, (ii) the external HX, (iii) the internal HX, (iv) the multi-path refrigerant circuit, and (v) a first set of one or more valves. The refrigeration system further includes 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.

Description

[Technical Field]

[0001] This generally relates to refrigeration systems, including but not limited to heating, ventilation, and air conditioning (HVAC) systems for controlling temperatures within compartments. [Background technology]

[0002] Heat pumps can use complex refrigerant circuits and can occupy a large physical area. Additionally, to operate efficiently, heat pumps can require additional components, such as accumulators to protect the compressor and other components of the heat pump. Existing systems can be costly and require significant space, energy, and installation time. Therefore, a refrigerant system that effectively uses the limited space available and has improved performance is needed.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of and claims priority to U.S. Patent Application No. 18 / 416,848, entitled "Heat Pump with Multi-Pass Refrigerant Circuit," filed January 18, 2024, which in turn claims priority to U.S. Provisional Patent Application No. 63 / 441,151, entitled "Heat Pump with Multi-Pass Refrigerant Circuit," filed January 25, 2023, each of which is incorporated herein by reference in its entirety. Summary of the Invention

[0004] The refrigerant systems and methods described herein improve system performance without increasing the space required to house the refrigerant system. In particular, the systems and methods disclosed herein improve the system efficiency (e.g., coefficient of performance (COP)) of refrigerant systems (e.g., heat pumps) operating in heating mode and air conditioning (AC) or cooling mode. In addition, the systems and methods disclosed herein lower the minimum operating ambient temperature while operating in heating mode, reduce the likelihood of compressor slug, and reduce the size of the accumulator required while operating in heating mode.

[0005] 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 fluidly 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 refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor. Alternatively, in the heating mode, the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

[0006] For example, a heat pump system can include a multi-pass refrigerant circuit, such as a double-pass refrigeration circuit, which, when operating in a cooling mode, uses a low-pressure, low-temperature refrigerant to reduce the temperature and pressure of a high-temperature, high-pressure discharge refrigerant to improve the 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 a heating mode), the double-pass heating circuit uses a high-pressure, high-temperature refrigerant to increase the temperature and pressure of a low-temperature, low-pressure suction refrigerant to improve the efficiency, performance, and reduce the minimum ambient operating temperature of the heat pump system.

[0007] In another aspect, a method is disclosed that is implemented in a refrigerant system. The refrigerant system can include a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one of one or more valves, a plurality of refrigerant lines fluidly coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, and (iv) the multi-pass refrigerant circuit via a first set of one or more valves, and a controller communicatively coupled to the first set of one or more valves. The method includes operating the refrigerant system in a cooling mode, in which the multi-pass refrigerant circuit uses refrigerant flow from the internal heat exchanger to reduce a temperature and pressure of the refrigerant flow from the compressor, and operating the refrigerant system in a heating mode, in which the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase a temperature and pressure of the refrigerant flow from the external heat exchanger.

[0008] In yet another aspect, a non-transitory computer-readable storage medium is disclosed that includes instructions for execution in a refrigeration system that, when executed by one or more processors of the refrigeration system, cause the refrigeration system to operate in a cooling mode in which a multi-pass refrigerant circuit uses refrigerant flow from an internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from a compressor, and in a heating mode in which the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from an external heat exchanger.

[0009] The features and advantages described herein are not necessarily all-inclusive, and in particular, certain additional features and advantages will become apparent to those skilled in the art upon consideration of the drawings, specification, and claims. Furthermore, it should be noted that the language used herein has been chosen primarily for readability and instructional purposes.

[0010] Having summarized the above exemplary aspects, a brief description of the drawings is presented. [Brief explanation of the drawings]

[0011] For a better understanding of the various described embodiments, the following description of the embodiments should be read in conjunction with the following drawings, in which like reference numerals refer to corresponding parts throughout the drawings:

[0012] [Figure 1A] 1 is a block diagram illustrating a refrigerant system operating in different modes, according to some embodiments. [Figure 1B] 1 is a block diagram illustrating a refrigerant system operating in different modes, according to some embodiments. [Figure 2A] 1 illustrates refrigerant flow through a multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. [Figure 2B] 1 illustrates refrigerant flow through a multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. [Figure 3A] 1 is a block diagram illustrating another embodiment of a refrigerant system operating in different modes, according to some embodiments. [Figure 3B] 1 is a block diagram illustrating another embodiment of a refrigerant system operating in different modes, according to some embodiments. [Figure 4A] 1 illustrates the flow of refrigerant through the multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. [Figure 4B] 1 illustrates the flow of refrigerant through the multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. [Figure 5A] 10A-10C are block diagrams illustrating yet another embodiment of a refrigerant system operating in different modes, according to some embodiments. [Figure 5B] 10A-10C are block diagrams illustrating yet another embodiment of a refrigerant system operating in different modes, according to some embodiments. [Figure 6] FIG. 1 is a flow diagram illustrating a method of operating a refrigerant system in one of multiple operating modes, according to some embodiments. [Figure 7]FIG. 2 is a block diagram illustrating a controller, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0013] This disclosure describes various embodiments of a refrigerant system. The refrigerant system can be part of a heat pump and / or an air conditioning system. In some embodiments, the refrigerant system is or is part of a heating, ventilation, and air conditioning (HVAC) system. The refrigerant system can be used in mobile applications (e.g., vehicles, trucks, aircraft, etc.) and / or structures (e.g., buildings, rooms, etc.). In some embodiments, the refrigerant system uses a multi-pass refrigerant circuit to improve the efficiency of the refrigerant system (e.g., improve the coefficient of performance (COP) of the refrigerant system in heating and AC modes). The use of a multi-pass refrigerant circuit also has the advantages of lowering the minimum operating ambient temperature for the heating mode, reducing the likelihood of compressor slug, and reducing the size of the accumulator required during the heating mode.

[0014] 1A and 1B are block diagrams illustrating a refrigeration system operating in different modes, according to 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-path refrigerant circuit 140, one or more valves (e.g., first valve 170), and multiple refrigerant lines 190 that fluidly couple one or more components of the refrigeration system 105. For example, the multiple refrigerant lines 190 can fluidly couple the compressor 110, the external heat exchanger 120, the internal heat exchanger 180, the multi-path refrigerant circuit 140, and one or more valves. In some embodiments, the refrigerant system 105 includes a controller 195 communicatively coupled to the compressor 110, one or more valves, and / or other components of the refrigerant system (e.g., heat exchanger, fan 125, metering device 130, accumulator 115, and / or one or more sensors 710 (e.g., temperature and / or pressure sensors) coupled to components of the refrigerant system 105.

[0015] In various embodiments, refrigerant system 105 includes one or more additional components not shown in FIGS. 1A-3B , such as a blower fan, control circuitry, a user interface, an air filter, a refrigerant reservoir, and the like. In some embodiments, refrigerant system 105 includes at least one user interface (e.g., a touchscreen) and at least one sensor 710 (e.g., a thermostat). In some embodiments, refrigerant system 105 includes at least one battery or power source and a battery monitoring system (sometimes referred to as a battery management module 719, as shown and described below with reference to FIG. 6 ). In some embodiments, battery monitoring module 719 is communicatively coupled to at least one sensor 710 (e.g., a current sensor). In some embodiments, battery monitoring system 719 comprises part of controller 195. In some embodiments, controller 195 is electrically coupled to other components of refrigerant system 105 (described below) to control the operation of these components.

[0016] The one or more valves may 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 four-way reversing valve) configured to change the direction of refrigerant flow. The first valve may 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 the direction of refrigerant flow. For example, as described below, the first valve 170 can change the refrigerant flow so that the refrigeration system 105 operates in the cooling mode 100 or the heating mode 150. In some embodiments, the first valve 170 is a. In some embodiments, the first valve 170 is coupled to the controller 195 and receives instructions from the controller to change the direction of the refrigerant flow (e.g., the first valve 170 is configured to selectively change the direction of the refrigerant flow via the controller in accordance with a change between the heating mode and the cooling mode). 1A, the first valve 170 is fluidly 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) fluidly coupled to an outlet or output of the compressor 110 via a first refrigerant line 190-1, (ii) fluidly coupled to the external heat exchanger 120 via a second refrigerant line 190-2, (iii) fluidly coupled to a fourth port of the multi-pass refrigerant circuit 140 via a sixth refrigerant line 190-6, and (iv) fluidly coupled to a fifth port of the multi-pass refrigerant circuit 140 via a seventh refrigerant line 190-7.

[0017] In some embodiments, the second valve 160 is a thermal expansion valve (TEV) or a temperature-sensitive expansion valve (TXV). In some embodiments, the second valve 160 is any type 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 may be fluidly 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 fluidly couples a second port of the multi-pass refrigerant circuit 140 to the internal heat exchanger 180, and a fifth refrigerant line 190-5 fluidly couples the internal heat exchanger 180 to a third port of the multi-pass refrigerant circuit 140. The second valve 160 is fluidly coupled (i) along the fourth refrigerant line 190-4 between the second port of the multi-path 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-path 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) configured to inhibit backflow of refrigerant (e.g., allow refrigerant to flow in one direction). The third valve 165 is fluidly coupled between the inlet and outlet of the second valve 160. 1A and 1B, third valve 165 is fluidly coupled between a first portion of fourth refrigerant line 190-4a and a second portion of fourth refrigerant line 190-4b (e.g., before and / or after the inlet and outlet of second valve 160). In this manner, third valve 165 either directs the refrigerant through second valve 160 or (depending on the mode of operation) allows the refrigerant to bypass second valve 160.

[0018] The refrigerant system 105 may further include a metering device 130. The metering device 130 may be 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-path refrigerant circuit 140. For example, as shown in FIG. 1A , the metering device 130 is fluidly 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-path refrigerant circuit 140, which are fluidly coupled via the third refrigerant line 190-3). If the multi-path refrigerant circuit 140 is not coupled between the external heat exchanger 120 and the internal heat exchanger 180, the metering device 130 may be fluidly coupled between the external heat exchanger 120 and the internal heat exchanger 180 (as shown and described below with reference to Figures 3A and 3B).

[0019] Compressor 110 is fluidly coupled to a sixth port of multi-pass refrigerant circuit 140 via an eighth refrigerant line 190-8. In some embodiments, accumulator 115 is coupled to an inlet of compressor 110. In some embodiments, compressor 110 is an electrically driven compressor. In some embodiments, eighth refrigerant line 190-8 fluidly couples the sixth port of multi-pass refrigerant circuit 140 and accumulator 115. In some embodiments, compressor 110 is a refrigerant compressor (e.g., a piston (reciprocating) compressor, a screw compressor, a scroll (spiral) compressor, an open compressor, a hermetic compressor, a semi-hermetic compressor, etc.). In some embodiments, compressor 110 is a vapor-injected scroll compressor or a variable speed compressor. In some embodiments, refrigeration system 105 includes a power source for powering compressor 110, controller 195, fan 125, and / or other components of the system. In some embodiments, the system is configured to operate independently (e.g., independently of the vehicle's operating state (e.g., without requiring the vehicle's engine to be on)). In some embodiments, the refrigerant system 105 includes multiple compressors.

[0020] In some embodiments, the refrigerant system 105 includes a fan 125 coupled to the external heat exchanger 120. The multi-pass refrigerant circuit 140 can be a double-pass heat exchanger.

[0021] When the refrigeration system 105 operates in a cooling mode, the multi-pass refrigerant circuit 140 reduces the temperature and pressure of the high-temperature, high-pressure discharge refrigerant using a low-pressure, low-temperature refrigerant to improve efficiency and performance. Refrigerant flow is represented by filled and unfilled chevron patterns. The filled chevron patterns represent discharge, high-temperature, and / or high-pressure flow. The unfilled chevron patterns represent suction line, low-temperature, and / or low-pressure flow. In some embodiments, while operating in a cooling mode, the refrigeration system 105 (i) routes refrigerant from the compressor 110 to the external heat exchanger 120 through 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), and (ii) routes refrigerant from the external heat exchanger 120 to the internal heat exchanger 180 through the multi-pass refrigerant circuit 140 (e.g., refrigerant flows from the external heat exchanger 120 to the multi-pass refrigerant circuit 140). (iii) causing the refrigerant to flow from the internal heat exchanger 180 through the multi-pass refrigerant circuit 140 and the first valve 170 to the compressor 110 (e.g., the 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 to the compressor 110 through the fifth and sixth ports of the multi-pass refrigerant circuit 140).

[0022] 1A , refrigerant system 105 operating in a cooling mode causes refrigerant to flow through one or more of metering device 130, second valve 160, third valve 165, and / or accumulator 115. For example, metering device 130 operates in a bypass mode, and refrigerant flows from external heat exchanger 120, through metering device 130, through first and second ports of multi-path refrigerant circuit 140, and through second valve 160 to internal heat exchanger 180.

[0023] 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 reduce the minimum ambient operating temperature. In the heating mode, the refrigerant flow is modified as represented by the filled and unfilled chevron patterns. In particular, when operating in the heating mode, the refrigeration system 105 (i) directs refrigerant 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 through the fourth and third ports of the multi-pass refrigerant circuit 140 to the first valve 170 and to the internal heat exchanger 180), and (ii) directs refrigerant from the internal heat exchanger 180 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140. (e.g., the refrigerant flows from the internal heat exchanger 180 through the second and first ports of the multi-path refrigerant circuit 140 to the external heat exchanger 120), and (iii) the refrigerant flows from the external heat exchanger 120 through the first valve 170 and the multi-path refrigerant circuit 140 to the compressor 110 (e.g., the refrigerant flows from the external heat exchanger 120 through the fifth and sixth ports of the multi-path refrigerant circuit 140 to the first valve 170 and to the compressor 110).

[0024] 1B , refrigerant system 105 operating in a heating mode causes refrigerant to flow through one or more of metering device 130, second valve 160, third valve 165, and / or accumulator 115. For example, refrigerant flows through third valve 165 (e.g., bypassing second valve 160), through second and first ports of multi-path refrigerant circuit 140, to metering device 130, which functions as an office tube, and to external heat exchanger 120.

[0025] 2A and 2B illustrate refrigerant flow through the multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. In particular, FIG. 2A shows a first cross-section 200 of the multi-pass refrigerant circuit 140 while the refrigerant system 105 is operating in the cooling mode 100, and FIG. 2B shows a second cross-section 250 of the multi-pass refrigerant circuit 140 while the refrigerant system 105 is operating in the heating mode 150.

[0026] In FIG. 2A, compressor 110 (FIGS. 1A-1B) directs its discharge to first valve 170 via first refrigerant line 190-1, first valve 170 directs refrigerant from compressor 110 via second refrigerant line 190-2 to external heat exchanger 120, the refrigerant passes through external heat exchanger 120 (e.g., via third refrigerant line 190-3, FIGS. 1A-1B) before returning to multi-path refrigerant circuit 140, which in turn directs refrigerant to internal heat exchanger 180 (e.g., via fourth refrigerant line 190-4, FIGS. 1A-1B). The refrigerant passes through an internal heat exchanger 180 (e.g., via a fifth refrigerant line 190-5, FIGS. 1A-1B) before returning to the multi-path refrigerant circuit 140, which directs the refrigerant to a first valve 170 via a sixth refrigerant line 190-6, which returns the refrigerant to the multi-path refrigerant circuit 140 via a seventh refrigerant line 190-7, and the multi-path refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via an eighth refrigerant line 190-8, FIGS. 1A-1B).

[0027] Refrigerant is discharged from compressor 110 at a high temperature and flows to external heat exchanger 120 at a high temperature (e.g., via first valve 170 and first refrigerant line 190-1 and second refrigerant line 190-2). As the high-temperature refrigerant passes through external heat exchanger 120 to multi-pass refrigerant circuit 140 (e.g., via third refrigerant line 190-3), its temperature decreases from high to medium-high (high-medium temperature being lower than high temperature). Multi-pass refrigerant circuit 140 directs the high-medium temperature refrigerant to internal heat exchanger 180 (e.g., via fourth refrigerant line 190-4). As the high-medium temperature refrigerant passes through internal heat exchanger 180 and returns to multi-pass refrigerant circuit 140 (e.g., via fifth refrigerant line 190-5), its temperature further decreases from medium-high to low (low temperature being lower than medium-high temperature and lower than the low-medium temperature refrigerant returned to compressor 110). The multi-pass refrigerant circuit 140 directs the low-temperature refrigerant to the first valve 170 (e.g., via a sixth refrigerant line 190-6), which returns the refrigerant to the multi-pass refrigerant circuit 140 (e.g., via a seventh refrigerant line 190-7). As the low-temperature refrigerant flows through the multi-pass refrigerant circuit 140, its temperature increases from low to low-medium temperature. The multi-pass refrigerant circuit 140 returns the low-temperature refrigerant to the compressor 110 (e.g., via an eighth refrigerant line 190-8).

[0028] In FIG. 2B , compressor 110 directs its discharge to first valve 170 via first refrigerant line 190-1, first valve 170 directs the refrigerant to multi-path refrigerant circuit 140 via sixth refrigerant line 190-6, multi-path refrigerant circuit 140 directs the refrigerant to internal heat exchanger 180 (e.g., via fifth refrigerant line 190-5), where the refrigerant passes through internal heat exchanger 180 before returning to multi-path refrigerant circuit 140 (e.g., via fourth refrigerant line 190-4), The multi-path 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 via the second refrigerant line 190-2 to the first valve 170, the first valve 170 directs the refrigerant to the multi-path refrigerant circuit 140 via the seventh refrigerant line 190-7, and the multi-path refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via the eighth refrigerant line 190-8).

[0029] Refrigerant is discharged from the compressor 110 at a high temperature and flows at a high temperature to the multi-path refrigerant circuit 140 (e.g., via the first valve 170, the first refrigerant line 190-1, and the sixth refrigerant line 190-6). The multi-path 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 to return to the multi-path refrigerant circuit 140 (e.g., via the fourth refrigerant line 190-4), its temperature decreases from a high temperature to a medium-high temperature. The multi-path 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 a medium-high temperature to a low temperature. As the low temperature refrigerant passes through first valve 170 and multi-pass refrigerant circuit 140 (e.g., via seventh refrigerant line 190-7), its temperature increases from low to low-medium temperature. Multi-pass refrigerant circuit 140 then returns the low-medium temperature refrigerant to compressor 110 (e.g., via eighth refrigerant line 190-8).

[0030] 3A and 3B are block diagrams illustrating another embodiment of a refrigeration system operating in different modes, according to some embodiments. Refrigeration system 305 includes components similar to those described above with reference to FIGS. 1A and 1B. In particular, refrigeration system 305 repositions one or more components, such as multi-path refrigerant circuit 140 and metering device 130. For example, in refrigeration system 305, an outlet of compressor 110 is fluidly coupled to a first port of multi-path refrigerant circuit 140 via first refrigerant line 390-1, a second port of multi-path refrigerant circuit 140 is fluidly coupled to first valve 170 via second refrigerant line 390-2, first valve 170 is fluidly coupled to external heat exchanger 120 via third refrigerant line 390-3, external heat exchanger 120 is fluidly coupled to internal heat exchanger 180 via fourth refrigerant line 390-4, and internal heat exchanger 180 is fluidly coupled to first valve 170 via second refrigerant line 390-5. The partial heat exchanger 180 is fluidly coupled to the third port of the multi-path refrigerant circuit via a fifth refrigerant line 390-5, the fourth port of the multi-path refrigerant circuit 140 is fluidly coupled to the first valve 170 via a sixth refrigerant line 390-6, the first valve 170 is fluidly coupled to the fifth port of the multi-path refrigerant circuit 140 via a seventh refrigerant line 390-7, and the sixth port of the multi-path refrigerant circuit 140 is fluidly coupled to the inlet of the compressor 110 via an eighth refrigerant line 390-8.

[0031] In some embodiments, the second valve 160 is coupled between the external heat exchanger 120 and the internal heat exchanger 180, and between the internal heat exchanger 180 and the multi-path refrigerant circuit 140. For example, as shown in Figures 3A and 3B, the second valve 160 is fluidly coupled (i) along the fourth refrigerant line 190-4 between the external heat exchanger 120 and the internal heat exchanger 180 (e.g., 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 line 190-4c), and (ii) along the fifth refrigerant line 190-5 between the first port of the multi-path refrigerant circuit 140 and the internal heat exchanger 180 (e.g., between a first portion of the fifth refrigerant line 190-5a and a second portion of the fifth refrigerant line 190-5b). The third valve 165 is fluidly coupled between the inlet and the outlet of the second valve 160. For example, as shown in Figures 3A and 3B, the third valve 165 is fluidly coupled between the first portion of the fourth refrigerant line 190-4a (or the second portion of the fourth refrigerant line 190-4b) and the third portion of the fourth refrigerant line 190-4c) and the third portion of the fourth refrigerant line 190-4c (e.g., before and / or after the inlet and outlet of the second valve 160).

[0032] Similarly, in some embodiments, metering device 130 is coupled between external heat exchanger 120 and internal heat exchanger 180. For example, as shown in Figures 3A and 3B, metering device 130 is fluidly coupled between a first portion of fourth refrigerant line 190-4a and a second portion of fourth refrigerant line 190-4b (or a third portion of fourth refrigerant line 190-4c).

[0033] While operating in cooling mode 300, refrigeration system 305 (i) causes refrigerant to flow from compressor 110 to external heat exchanger 120 via multi-path refrigerant circuit 140 and first valve 170 (e.g., refrigerant flows from compressor 110 through first and second ports of multi-path refrigerant circuit 140 to first valve 170, and from first valve 170 to external heat exchanger 120), (ii) causes refrigerant to flow from external heat exchanger 120 to internal heat exchanger 180, and (iii) causes refrigerant to flow from internal heat exchanger 180 to compressor 110 via multi-path refrigerant circuit 140 and first valve 170 (e.g., refrigerant flows from internal heat exchanger 180 to compressor 110 via multi-path refrigerant circuit 140 and first valve 170 through third and fourth ports of multi-path refrigerant circuit 140 to first valve 170, and from first valve 170 to compressor 110 through fifth and sixth ports of multi-path refrigerant circuit 140).

[0034] 3A , refrigerant system 305 operating in a cooling mode causes refrigerant to flow through one or more of metering device 130, second valve 160, third valve 165, and / or accumulator 115. For example, refrigerant can flow from external heat exchanger 120 through metering device 130 (e.g., operating in bypass mode) and / or through second valve 160 to internal heat exchanger 180.

[0035] 3B, refrigeration system 305 is shown operating in a heating mode. In particular, when operating in heating mode 350, refrigeration system 305 (i) causes refrigerant to flow from compressor 110 through multi-pass refrigerant circuit 140 and first valve 170 to internal heat exchanger 180 (e.g., refrigerant flows from compressor 110 through first and second ports of multi-pass refrigerant circuit 140 to first valve 170, and from first valve 170 through fourth and third ports of multi-pass refrigerant circuit 140 to internal heat exchanger 180). (ii) the refrigerant flows from the internal heat exchanger 180 to the external heat exchanger 120; and (iii) the refrigerant flows from the external heat exchanger 120 to the compressor 110 via the first valve 170 and the multi-path refrigerant circuit 140 (e.g., the refrigerant flows from the external heat exchanger 120 to the first valve 170 and from the first valve 170 to the compressor 110 through the fifth and sixth ports of the multi-path refrigerant circuit 140).

[0036] 3B, refrigerant system 105 operating in a heating mode causes refrigerant to flow through one or more of metering device 130, second valve 160, third valve 165, and / or accumulator 115. For example, refrigerant flows through third valve 165 (e.g., bypassing second valve 160), to metering device 130, which functions as an office tube, and to external heat exchanger 120.

[0037] 4A and 4B illustrate refrigerant flow through the multi-pass refrigerant circuit 140 during cooling and heating modes, according to some embodiments. In particular, FIG. 4A shows a first cross-section 400 of the multi-pass refrigerant circuit 140 while the refrigerant system 305 is operating in the cooling mode 300, and FIG. 4B shows a second cross-section 450 of the multi-pass refrigerant circuit 140 while the refrigerant system 305 is operating in the heating mode 350.

[0038] In FIG. 4A , compressor 110 (FIGS. 3A-3B) directs discharge to multi-path refrigerant circuit 140 via first refrigerant line 390-1, multi-path refrigerant circuit 140 directs refrigerant via second refrigerant line 390-2 to first valve 170, first valve 170 directs refrigerant via third refrigerant line 390-3 to external heat exchanger 120, where the refrigerant passes through external heat exchanger 120 toward internal heat exchanger 180 (e.g., via fourth refrigerant line 390-4, FIGS. 3A-3B ), where the refrigerant The refrigerant passes through internal heat exchanger 180 (e.g., via fifth refrigerant line 390-5, FIGS. 3A-3B) before returning to multi-path refrigerant circuit 140, which directs the refrigerant via sixth refrigerant line 390-6 to first valve 170, which returns the refrigerant via seventh refrigerant line 390-7 to multi-path refrigerant circuit 140, which directs the refrigerant back to compressor 110 (e.g., via eighth refrigerant line 390-8, FIGS. 3A-3B).

[0039] Refrigerant is discharged from compressor 110 at a high temperature and flows at a high temperature into multi-pass refrigerant circuit 140 (e.g., via first refrigerant line 390-1). Multi-pass refrigerant circuit 140 directs the high-temperature refrigerant to first valve 170 (e.g., via second refrigerant line 390-2), which directs the high-temperature refrigerant to external heat exchanger 120 (e.g., via third refrigerant line 390-3). As the high-temperature refrigerant passes through external heat exchanger 120 to internal heat exchanger 180 (e.g., via fourth refrigerant line 390-4), and from internal heat exchanger 180 through multi-pass refrigerant circuit 140 (e.g., via fifth refrigerant line 390-5), its temperature decreases from a high temperature to a low temperature. The multi-path refrigerant circuit 140 directs the low-temperature refrigerant to the first valve 170 (e.g., via a sixth refrigerant line 390-6), which returns the refrigerant to the multi-path refrigerant circuit 140 (e.g., via a seventh refrigerant line 390-7). As the low-temperature refrigerant passes through the multi-path refrigerant circuit 140, its temperature increases from low to low-medium. The multi-path refrigerant circuit 140 then returns the low-temperature refrigerant to the compressor 110 (e.g., via an eighth refrigerant line 390-8).

[0040] In FIG. 4B , the compressor 110 directs its discharge to the multi-path refrigerant circuit 140 via a first refrigerant line 390-1, the multi-path 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-path refrigerant circuit 140 via a sixth refrigerant line 390-6, the multi-path refrigerant circuit 140 directs the refrigerant to the internal heat exchanger 180 (e.g., via a fifth refrigerant line 390-5), and the refrigerant The refrigerant passes through the internal heat exchanger 180 to the external heat exchanger 120 (e.g., via the fourth refrigerant line 390-4), the refrigerant passes through the external heat exchanger 120 to the first valve 170 (e.g., via the third refrigerant line 390-3), the first valve 170 returns the refrigerant to the multi-path refrigerant circuit 140 via the seventh refrigerant line 390-7, and the multi-path refrigerant circuit 140 directs the refrigerant back to the compressor 110 (e.g., via the eighth refrigerant line 390-8).

[0041] Refrigerant is discharged from compressor 110 at a high temperature and flows at a high temperature to multi-path refrigerant circuit 140 (e.g., via first refrigerant line 390-1). Multi-path refrigerant circuit 140 directs the high-temperature refrigerant to first valve 170 (e.g., via second refrigerant line 390-2). As the high-temperature refrigerant passes through first valve 170 and returns to multi-path refrigerant circuit 140 (e.g., via sixth refrigerant line 390-6), and as it passes through multi-path refrigerant circuit 140, its temperature decreases from high to medium-high. Multi-path refrigerant circuit 140 directs the high-temperature medium-high refrigerant to interior heat exchanger 180 (e.g., via fifth refrigerant line 390-5). As the high-temperature medium-temperature refrigerant passes through internal heat exchanger 180 to external heat exchanger 120 (e.g., via fourth refrigerant line 390-4) and through external heat exchanger 120 toward first valve 170 (e.g., via third refrigerant line 390-3), its temperature decreases from high-temperature medium-temperature to low-temperature medium-temperature. As the low-temperature refrigerant passes through multi-pass refrigerant circuit 140 (e.g., via seventh refrigerant line 390-7) and through multi-pass refrigerant circuit 140 to first valve 170, its temperature increases from low-temperature to low-temperature medium-temperature. Multi-pass refrigerant circuit 140 then returns the low-temperature medium-temperature refrigerant to compressor 110 (e.g., via eighth refrigerant line 390-8).

[0042] 5A and 5B are block diagrams illustrating yet another embodiment of a refrigerant system operating in different modes, according to some embodiments. Refrigerant system 505 includes similar components as those described above with reference to FIGS. 1A and 1B; however, refrigerant system 505 eliminates metering device 130 and third valve 165. In particular, refrigerant system 505 includes compressor 110, accumulator 115, external heat exchanger 120, internal heat exchanger 180, multi-path refrigerant circuit 140, one or more valves (e.g., first valve 170), multiple refrigerant lines 190 and 590 fluidly coupling one or more components of refrigerant system 105, and a controller 195 and / or one or more sensors 710 coupled to one or more components of refrigerant system 505. Refrigerant system 505 further includes an additional fan 126 or blower adjacent to internal heat exchanger 180. Refrigerant system 505 includes and operates in the same modes (e.g., cooling mode 500 and heating mode 550) as described above with reference to refrigerant system 105. In particular, the refrigerant flow through multi-pass refrigerant circuit 140 for each mode is similar to the flow described above with reference to Figures 1A and 1B. Additional advantages provided by refrigerant system 505 include reduced cost, a simplified system, and a smaller form factor.

[0043] 6 is a flow diagram illustrating a method 600 of operating a refrigerant system in one of multiple operating modes, according to some embodiments. In some embodiments, method 600 is performed by a refrigerant system (e.g., refrigerant systems 105 and 305) or a component of a refrigerant system, such as controller 195. In some implementations, method 600 is governed by instructions stored on a non-transitory computer-readable storage medium (e.g., memory 708, FIG. 6), which are executed by one or more processors of an electronic device (e.g., processor 702, FIG. 6). For convenience, method 600 is described below as being performed by refrigerant systems 105 and 305.

[0044] The method 600 includes operating 610 the refrigeration system 105, 305, or 505 in a cooling mode. In the cooling mode, the multi-pass refrigerant circuit 140 (FIGS. 1A-4B) uses 615 the refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor.

[0045] With respect to the refrigerant system 105 described above with reference to Figures 1A and 1B, operating in a cooling mode includes flowing refrigerant from the compressor 110 to the external heat exchanger 120 through one or more valves (e.g., the first valve 170), flowing refrigerant from the external heat exchanger 120 to the internal heat exchanger 180 through the multi-pass refrigerant circuit 140, and flowing refrigerant from the internal heat exchanger 180 to the compressor 110 through the multi-pass refrigerant circuit 140 and one or more valves. In particular, the refrigerant is caused to flow (i) from the compressor 110 to the first valve 170 and to the external heat exchanger 120, (ii) from the external heat exchanger 120 (e.g., via the metering device 130 and the second valve 160) through the first and second ports of the multi-path refrigerant circuit 140 to the internal heat exchanger 180, and (iii) from the internal heat exchanger 180 (via the second valve 160) to the third and fourth ports of the multi-path refrigerant circuit 140 to the first valve 170, and from the first valve 170 through the fifth and sixth ports of the multi-path refrigerant circuit 140 to the compressor 110.

[0046] With respect to the refrigerant system 305 described above with reference to Figures 3A and 3B, operating in a cooling mode includes flowing refrigerant from the compressor 110 to the external heat exchanger 120 via the multi-path refrigerant circuit 140 and one or more valves (e.g., the first valve 170), flowing refrigerant from the external heat exchanger 120 to the internal heat exchanger 180, and flowing refrigerant from the internal heat exchanger 180 to the compressor 110 via the multi-path refrigerant circuit 140 and one or more valves. In particular, the refrigerant (i) flows from the compressor 110 through the first and second ports of the multi-path refrigerant circuit 140 to the first valve 170 and from the first valve 170 to the external heat exchanger, (ii) flows 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) flows from the internal heat exchanger 180 through the third and fourth ports of the multi-path refrigerant circuit 140 to the first valve 170 and from the first valve 170 to the compressor 110 through the fifth and sixth ports of the multi-path refrigerant circuit 140.

[0047] The method 600 includes operating 620 the refrigeration system 105, 305, or 505 in a heating mode. In the heating mode, the multi-pass refrigerant circuit 140 uses 625 the refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

[0048] With respect to the refrigerant system 105 described above with reference to Figures 1A and 1B, operating in a heating mode includes flowing refrigerant from the compressor 110 to the internal heat exchanger 180 via one or more valves (e.g., first valve 170) and the multi-pass refrigerant circuit 140, flowing refrigerant from the internal heat exchanger 180 to the external heat exchanger 120 via the multi-pass refrigerant circuit 140, and flowing refrigerant from the external heat exchanger 120 to the compressor 110 via one or more valves and the multi-pass refrigerant circuit 140. In particular, the refrigerant flows (i) from the compressor 110 through the fourth and third ports of the multi-path refrigerant circuit 140 to the first valve 170 and to the internal heat exchanger 180 (via the second valve 160), (ii) from the internal heat exchanger 180 through the third valve 165, the second and first ports of the multi-path refrigerant circuit 140, and the metering device 130 to the external heat exchanger 120, and (iii) from the external heat exchanger 120 through the fifth and sixth ports of the multi-path refrigerant circuit 140 to the first valve 170 and to the compressor 110.

[0049] With respect to the refrigerant system 305 described above with reference to Figures 3A and 3B, operating in a heating mode includes flowing refrigerant from the compressor 110 to the internal heat exchanger 180 via the multi-path refrigerant circuit 140 and one or more valves (e.g., the first valve 170), flowing refrigerant from the internal heat exchanger 180 to the external heat exchanger 120, and flowing refrigerant from the external heat exchanger 120 to the compressor 110 via one or more valves and the multi-path refrigerant circuit 140. In particular, the refrigerant flows (i) from the compressor 110 through the first and second ports of the multi-path refrigerant circuit 140 to the first valve 170, and from the first valve 170 through the fourth and third ports of the multi-path refrigerant circuit 140 to the internal heat exchanger 180 (through the second valve 160), (ii) from the internal heat exchanger 180 to the external heat exchanger 120 (e.g., through the third valve 165 and the metering device 130), and (iii) from the external heat exchanger 120 to the first valve 170 and from the first valve 170 to the compressor 110 through the fifth and sixth ports of the multi-path refrigerant circuit 140.

[0050] 7 is a block diagram illustrating a controller 195, according to 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 referred to as a chipset). According to 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 an 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 located remotely from the one or more processors 702. Memory 708, or alternatively, the non-volatile memory within memory 708, comprises a non-transitory computer-readable storage medium. In some embodiments, memory 708 or the non-transitory computer-readable storage medium of memory 708 stores the following programs, modules, and data structures, or a subset or superset thereof: operational logic 714, which includes procedures for handling various basic system services and performing hardware-dependent tasks; a communications module 716 for communicatively connecting the controller 195 to other computing devices (e.g., vehicle control systems or client devices) over one or more networks (e.g., the Internet); an interface module 717 for presenting information to a user and detecting user input (e.g., in conjunction with the communications interface 704); a state module 718 for setting and / or adjusting the operating state of the conditioning system (e.g., heating or cooling mode); a battery monitoring module 719 for distributing and / or monitoring power to one or more components of the refrigerant system; and A database 720 that stores data for use in managing the operation of a refrigeration system (e.g., refrigeration systems 105 and 305), including, but not limited to: sensor information 722 that stores information about one or more sensors associated with the conditioning system (e.g., temperature data, pressure data, and / or current data); Component settings 724 that store information about one or more components of the conditioning system (e.g., operational settings such as speed and power); and user information 726, which stores information about user preferences, settings, history, etc.

[0051] Each of the above-identified elements may be stored in one or more of the aforementioned memory devices and corresponds to a set of instructions for performing the functions described above. The above-identified modules or programs (i.e., sets of instructions) need not be implemented as separate software programs, procedures, or modules; thus, various subsets of these modules may be combined or otherwise rearranged in various embodiments. In some embodiments, memory 708 optionally stores a subset of the above-identified modules and data structures. Additionally, 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.

[0052] Although some of the various figures illustrate some logical stages in a particular order, stages that are not order-dependent may be reordered, and other stages may be combined or broken down. While some reordering or other groupings are specifically mentioned, the reordering and groupings presented herein are not an exhaustive list of alternatives, as other reorderings and groupings will be apparent to those of ordinary skill in the art after reading this disclosure.

[0053] Having now described a system block diagram and then an exemplary refrigerant system, attention will now turn to specific exemplary embodiments.

[0054] Some illustrative aspects will now be briefly described.

[0055] (A1) According to some embodiments, a refrigerant system is disclosed. The refrigerant 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 fluidly 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 refrigerant system in multiple modes, including a cooling mode and a heating mode. In the cooling mode, the multi-pass refrigerant circuit uses refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor. In the heating mode, the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

[0056] (A2) In some embodiments of A1, the refrigerant system includes a metering device (e.g., a metering piston) fluidly 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 (when there is a multi-pass circuit between the external and internal heat exchangers).

[0057] (A3) In some embodiments of A1-A2, the refrigerant system further includes a second valve (eg, a thermal expansion valve) fluidly coupled between the internal heat exchanger and / or the multi-pass circuit.

[0058] (A4) In some embodiments of A3, the refrigerant system further includes a third valve (eg, a check valve) fluidly coupled between the inlet and outlet of the second valve.

[0059] (A5) In some embodiments of A4, the third valve includes one or more check valves configured to inhibit backflow of refrigerant.

[0060] (A6) In some embodiments of A1-A5, the refrigerant system further includes an accumulator fluidly coupled between the compressor and the multi-pass circuit. In some embodiments, the accumulator is coupled to the compressor.

[0061] (A7) In some embodiments of A1-A6, the refrigerant system further includes a fan coupled to the external heat exchanger.

[0062] (A8) In some embodiments of A1-A7, the one or more valves are four-way reversing valves configured to selectively change the direction of refrigerant flow via the controller in accordance with changes between heating and cooling modes.

[0063] (A9) In some embodiments of A1-A8, the plurality of refrigerant lines include a first refrigerant line fluidly coupling an output of the compressor to one or more valves; a second refrigerant line fluidly coupling the one or more valves to an external heat exchanger; a third refrigerant line fluidly coupling the external heat exchanger to a first port of the multipass circuit; a fourth refrigerant line fluidly coupling a second port of the multipass circuit to an internal heat exchanger; a fifth refrigerant line fluidly coupling the internal heat exchanger to a third port of the multipass circuit; a sixth refrigerant line fluidly coupling the fourth port of the multipass circuit to one or more valves; a seventh refrigerant line fluidly coupling the one or more valves to the fifth port of the multipass circuit; and an eighth refrigerant line fluidly coupling the sixth port of the multipass circuit to an inlet of the compressor.

[0064] (A9.5) In some embodiments of A9, operating in a cooling mode includes flowing a refrigerant from the compressor through one or more valves to an external heat exchanger, flowing the refrigerant from the external heat exchanger through a multi-pass circuit to an internal heat exchanger, and flowing the refrigerant from the internal heat exchanger through the multi-pass circuit and one or more valves to the compressor. The refrigerant is flowed from the compressor to the one or more valves and to the external heat exchanger, from the external heat exchanger through first and second ports of the multi-pass circuit to the internal heat exchanger, from the internal heat exchanger to third and fourth ports of the multi-pass circuit and to one or more valves, and from the one or more valves through fifth and sixth ports of the multi-pass circuit to the compressor.

[0065] (A10) In some embodiments of A8-A9.5, operating in the heating mode includes flowing a refrigerant from the compressor through one or more valves and a multipass circuit to an internal heat exchanger, flowing the refrigerant from the internal heat exchanger through the multipass circuit to an external heat exchanger, and flowing the refrigerant from the external heat exchanger through one or more valves and the multipass circuit to the compressor. The refrigerant is flowed from the compressor through fourth and third ports of the multipass circuit to one or more valves and to the internal heat exchanger, the refrigerant is flowed from the internal heat exchanger through second and first ports of the multipass circuit to the external heat exchanger, and from the external heat exchanger through fifth and sixth ports of the multipass circuit to one or more valves and to the compressor.

[0066] (A11) In some embodiments of A1-A7, the plurality of refrigerant lines include a first refrigerant line fluidly coupling an outlet of the compressor to a first port of the multipass circuit; a second refrigerant line fluidly coupling a second port of the multipass circuit to one or more valves; a third refrigerant line fluidly coupling the one or more valves to an external heat exchanger; a fourth refrigerant line fluidly coupling the external heat exchanger to an internal heat exchanger; a fifth refrigerant line fluidly coupling the internal heat exchanger to the third port of the multipass circuit; a sixth refrigerant line fluidly coupling the fourth port of the multipass circuit to one or more valves; a seventh refrigerant line fluidly coupling the one or more valves to the fifth port of the multipass circuit; and an eighth refrigerant line fluidly coupling the sixth port of the multipass circuit to the inlet of the compressor.

[0067] (A12) In some embodiments of A11, operating in the cooling mode includes causing refrigerant to flow from the compressor through one or more valves to an external heat exchanger, causing refrigerant to flow from the external heat exchanger through a multi-pass circuit to an internal heat exchanger, and causing refrigerant to flow from the internal heat exchanger through the multi-pass circuit and one or more valves to the compressor, wherein the refrigerant is caused to flow from the compressor through 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 to the one or more valves through third and fourth ports of the multi-pass circuit to the one or more valves and from the one or more valves to the compressor through fifth and sixth ports of the multi-pass circuit.

[0068] (A13) In some embodiments of A11-A12, operating in the heating mode includes flowing refrigerant from the compressor through a multipass circuit and one or more valves to an internal heat exchanger, flowing refrigerant from the internal heat exchanger to an external heat exchanger, and flowing refrigerant from the external heat exchanger through one or more valves and the multipass circuit to the compressor. The refrigerant is flowed from the compressor through first and second ports of the multipass circuit to one or more valves, and from the one or more valves through fourth and third ports of the multipass circuit to the internal heat exchanger, from the internal heat exchanger to the external heat exchanger, and from the external heat exchanger to one or more valves and from the one or more valves to the compressor through fifth and sixth ports of the multipass circuit.

[0069] (A14) In some embodiments of A1-A13, the refrigeration system is a heating, ventilation and air conditioning (HVAC) system.

[0070] (A15) In some embodiments of A1-A14, the compressor is an electrically driven compressor.

[0071] (B1) According to some embodiments, a method is disclosed that is implemented in a refrigerant system. The method is implemented in the refrigerant system including a compressor, an external heat exchanger, an internal heat exchanger, a multi-pass refrigerant circuit, one of one or more valves, a plurality of refrigerant lines fluidly coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, and (iv) the multi-pass refrigerant circuit via a first set of one or more valves, and a controller communicatively coupled to the first set of one or more valves. The method includes operating the refrigerant system in a cooling mode and operating the refrigerant system in a heating mode. In the cooling mode, the multi-pass refrigerant circuit uses refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor. In the heating mode, the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

[0072] (B2) In some embodiments of B1, the refrigerant system is configured according to and to perform the refrigerant system operations of A2-A15.

[0073] (C1) According to some embodiments, a non-transitory computer-readable storage medium is disclosed. The 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 a heating mode. When the refrigeration system is operated in the cooling mode, the multi-pass refrigerant circuit uses refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor. When the refrigeration system is operated in the heating mode, the multi-pass refrigerant circuit uses refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

[0074] (C2) In some embodiments of C1, the refrigerant system is configured according to and configured to perform the refrigerant system operations of A1-A15.

[0075] Although terms such as "first," "second," and the like are sometimes used herein to describe various elements, it should also be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first valve may be referred to as a second valve, and similarly, a second valve may be referred to as a first valve, without departing from the scope of the various described embodiments. Although a first valve and a second valve are both valves, they are not the same valve unless explicitly stated otherwise.

[0076] The terminology used in describing the various described embodiments herein is merely for the purpose of describing particular embodiments and is not intended to be limiting. When used in describing 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 dictates otherwise. As used herein, the term "and / or" should also be understood to refer to and include any and all possible combinations of one or more of the associated listed items. It should be further understood that as used herein, the terms "includes," "including," "comprises," and / or "comprising" specify the presence of stated features, components, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, components, steps, operations, elements, components, and / or groups thereof.

[0077] As used herein, the term "when" is interpreted, optionally depending on the context, to mean "when" or "when" or "response to determining" or "response to detecting" or "pursuant to determining." Similarly, the phrase "when it is determined" or "when [described condition or event] is detected" is interpreted, optionally depending on the context, to mean "upon determining" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]" or "pursuant to determining that [described condition or event] has been detected."

[0078] The foregoing description has been set forth with reference to specific embodiments for purposes of explanation. However, the exemplary discussion above is not intended to be exhaustive or to limit the scope of the claims to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments were selected to best explain the principles underlying the claims and their practical application, thereby enabling those skilled in the art to best utilize the embodiments with various modifications as suited to the particular application contemplated.

Claims

1. 1. A refrigerant system comprising: A compressor and an external heat exchanger; an internal heat exchanger; a multi-path refrigerant circuit; one or more valves; (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, (iv) the multi-path refrigerant circuit, and (v) a plurality of refrigerant lines fluidly coupling the one or more valves; communicatively coupled to the one or more valves; and a cooling mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor; and and a controller configured to operate the system in multiple modes, including a heating mode in which the multi-path refrigerant circuit uses the refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

2. The refrigerant system of claim 1 , further comprising a metering device fluidly coupled between the external heat exchanger and the internal heat exchanger.

3. 10. The refrigeration system of any one of the preceding claims, further comprising a second valve fluidly coupled between the internal heat exchanger and / or the multi-path refrigerant circuit.

4. The refrigerant system of claim 3 further comprising a third valve fluidly coupled between the inlet and outlet of the second valve.

5. The system of claim 4 , wherein the third valve comprises one or more check valves configured to inhibit backflow of the refrigerant.

6. 10. A refrigeration system according to any one of the preceding claims, further comprising an accumulator fluidly coupled between the compressor and the multi-pass refrigerant circuit.

7. 10. The refrigerant system of any one of the preceding claims, further comprising a fan coupled to the external heat exchanger.

8. 10. A refrigerant system as claimed in any one of the preceding claims, wherein the one or more valves are four-way reversing valves configured to selectively change direction of refrigerant flow in accordance with changes between heating and cooling modes via the controller.

9. The plurality of refrigerant lines are a first refrigerant line fluidly coupling the output of the compressor to the one or more valves; a second refrigerant line fluidly coupling the one or more valves to the external heat exchanger; a third refrigerant line fluidly coupling the external heat exchanger to a first port of the multi-path refrigerant circuit; a fourth refrigerant line fluidly coupling a second port of the multi-path refrigerant circuit to the internal heat exchanger; a fifth refrigerant line fluidly coupling the internal heat exchanger to a third port of the multi-path refrigerant circuit; a sixth refrigerant line fluidly coupling a fourth port of the multi-path refrigerant circuit to the one or more valves; a seventh refrigerant line fluidly coupling the one or more valves to a fifth port of the multi-path refrigerant circuit; an eighth refrigerant line fluidly coupling a sixth port of the multi-path refrigerant circuit to an inlet of the compressor.

10. Operating in the cooling mode allowing a refrigerant to flow from the compressor through the one or more valves to the external heat exchanger, wherein the refrigerant is allowed to flow from the compressor to the one or more valves and to the external heat exchanger; flowing the refrigerant from the external heat exchanger to the internal heat exchanger through the multi-path refrigerant circuit, wherein the refrigerant is flowed from the external heat exchanger through the first and second ports of the multi-path refrigerant circuit to the internal heat exchanger; 10. The refrigerant system of claim 9, including flowing the refrigerant from the internal heat exchanger through the multi-path refrigerant circuit and the one or more valves to the compressor, wherein the refrigerant is caused to flow from the internal heat exchanger to the third and fourth ports of the multi-path refrigerant circuit, to the one or more valves, and from the one or more valves through the fifth and sixth ports of the multi-path refrigerant circuit to the compressor.

11. operating in the heating mode, flowing the refrigerant from the compressor through the one or more valves and the multi-path refrigerant circuit to the internal heat exchanger, wherein the refrigerant is flowed from the compressor through the fourth and third ports of the multi-path refrigerant circuit to the one or more valves and to the internal heat exchanger; flowing the refrigerant from the internal heat exchanger to the external heat exchanger through the multi-path refrigerant circuit, wherein the refrigerant is flowed from the internal heat exchanger through the second and first ports of the multi-path refrigerant circuit to the external heat exchanger; and flowing the refrigerant from the external heat exchanger through the one or more valves and the multi-path refrigerant circuit to the compressor, wherein the refrigerant is flowed from the external heat exchanger through the fifth and sixth ports of the multi-path refrigerant circuit to the one or more valves and to the compressor.

12. The plurality of refrigerant lines are a first refrigerant line fluidly coupling an outlet of the compressor to a first port of the multi-pass refrigerant circuit; a second refrigerant line fluidly coupling a second port of the multi-path refrigerant circuit to the one or more valves; a third refrigerant line fluidly coupling the one or more valves to the external heat exchanger; a fourth refrigerant line fluidly coupling the external heat exchanger to the internal heat exchanger; a fifth refrigerant line fluidly coupling the internal heat exchanger to a third port of the multi-path refrigerant circuit; a sixth refrigerant line fluidly coupling a fourth port of the multi-path refrigerant circuit to the one or more valves; a seventh refrigerant line fluidly coupling the one or more valves to a fifth port of the multi-path refrigerant circuit; an eighth refrigerant line fluidly coupling a sixth port of the multi-path refrigerant circuit to an inlet of the compressor.

13. Operating in the cooling mode flowing a refrigerant from the compressor through the multi-path refrigerant circuit and the one or more valves to the external heat exchanger, wherein the refrigerant flows from the compressor through the first and second ports of the multi-path refrigerant circuit to the one or more valves and from the one or more valves to the external heat exchanger; flowing the refrigerant from the external heat exchanger to the internal heat exchanger; 13. The refrigerant system of claim 12, comprising: flowing the refrigerant from the internal heat exchanger through the multi-path refrigerant circuit and the one or more valves to the compressor, wherein the refrigerant is flowed from the internal heat exchanger through the third and fourth ports of the multi-path refrigerant circuit to the one or more valves and from the one or more valves to the compressor through the fifth and sixth ports of the multi-path refrigerant circuit.

14. operating in the heating mode, flowing the refrigerant from the compressor through the multi-path refrigerant circuit and the one or more valves to the internal heat exchanger, wherein the refrigerant flows from the compressor through the first and second ports of the multi-path refrigerant circuit to the one or more valves and from the one or more valves to the internal heat exchanger through the fourth and third ports of the multi-path refrigerant circuit; flowing the refrigerant from the internal heat exchanger to the external heat exchanger; and flowing the refrigerant from the external heat exchanger through the one or more valves and the multi-path refrigerant circuit to the compressor, wherein the refrigerant is flowed from the external heat exchanger to the one or more valves and from the one or more valves to the compressor through the fifth and sixth ports of the multi-path refrigerant circuit.

15. Refrigerant system according to any one of the preceding claims, wherein the refrigerant system is a heating, ventilation and air conditioning (HVAC) system.

16. Refrigerant system according to any one of the preceding claims, wherein the compressor is an electrically driven compressor.

17. 1. A method comprising:

1. A refrigeration system comprising: a compressor; an external heat exchanger; an internal heat exchanger; a multi-path refrigerant circuit; one or more valves; a plurality of refrigerant lines fluidly coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, and (iv) the multi-path refrigerant circuit through the one or more valves; and a controller communicatively coupled to the one or more valves. operating the refrigeration system in a cooling mode in which the multi-pass refrigerant circuit uses refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor; operating the refrigeration system in a heating mode in which the multi-pass refrigerant circuit uses the refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from the external heat exchanger.

18. 18. The method of claim 17, wherein the refrigerant system is configured according to and adapted to carry out the operation of a refrigerant system as defined in claims 2 to 16.

19. When executed by one or more processors, the method provides a refrigerant system including a compressor, an external heat exchanger, an internal heat exchanger, a multi-path refrigerant circuit, one or more valves, and a plurality of refrigerant lines fluidly coupling (i) the compressor, (ii) the external heat exchanger, (iii) the internal heat exchanger, and (iv) the multi-path refrigerant circuit via the one or more valves, the method provides the refrigerant system with: a multi-pass refrigerant circuit operating in a cooling mode using the refrigerant flow from the internal heat exchanger to reduce the temperature and pressure of the refrigerant flow from the compressor; and 12. A non-transitory computer-readable storage medium comprising instructions for operating the multi-path refrigerant circuit in a heating mode using the refrigerant flow from the compressor to increase the temperature and pressure of the refrigerant flow from an external heat exchanger.

20. 20. The non-transitory computer-readable storage medium of claim 19, wherein the refrigerant system is configured according to and configured to perform the operation of the refrigerant system of claims 2-16.

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