JP2009008383A - Co2 refrigeration system having heat pump and multiple modes of operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CO<SB>2</SB>heat pump system and its manufacturing method without causing the practical problem such as requiring a valve capable of coping with high pressure CO<SB>2</SB>, an accumulator of a proper size and a system inside heat exchanger endurable against high system pressure in a whole reversible system. <P>SOLUTION: While a refrigeration system 10 is operated in an air-conditioning or cooling (A/C) mode, CO<SB>2</SB>of a refrigerant enters a first evaporator 14 from a compressor 12, and then, enters a second evaporator 18. A liquid coolant flows through a second coolant loop 19, and further lowers the refrigerant temperature, but a heat load of the second evaporator 18 can be reduced more than that of the air-cooled first evaporator 14. The refrigerant coming out of the second evaporator flows in the high pressure side of a suction line inside heat exchanger 20 before turning to an expansion device or an expansion valve 22, and flows in an air to refrigerant type evaporator 24 after coming out of the expansion valve 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

This application claims priority from US Provisional Patent Application No. 60 / 933,713, filed June 8, 2007.
The present invention relates to a cooling system, and more particularly, to a transcritical system or a CO ₂ cooling system having both an air heating mode or a heat pump mode and an air conditioning mode or a cooling mode.

In principle, the CO ₂ heat pump system changes the flow direction in the system cycle so that the A / C mode evaporator operates as an HP mode gas cooler and the A / C mode gas cooler operates as an HP mode evaporator. By doing so, it is possible to switch from the heat pump mode or the heating (HP) mode to the air conditioning mode or the cooling (A / C) mode. However, this method requires, but is not limited to, a valve that can handle high pressure CO ₂ , an appropriately sized accumulator, and an in-system heat exchanger that can withstand the high system pressure in a fully reversible system. There are some practical problems.

US Provisional Patent Application No. 60 / 933,713

A CO ₂ heat pump system that does not require practical problems such as a valve that can cope with high-pressure CO ₂ , an appropriately sized accumulator, and an in-system heat exchanger that can withstand high system pressure in a fully reversible system, and its manufacture Is to provide a method.

According to the present invention, it is possible to operate under both HP and A / C modes without changing the refrigerant flow direction in the system by doubling the coolant loop and adding a heat exchanger. A cooling system is provided. This cooling system is preferably used for air conditioning in a truck cabin with the engine stopped. In some embodiments, CO ₂ is used as a refrigerant in at least one refrigerant circuit.
In one embodiment, the present invention provides a cooling system that includes both a heating mode for heating the cargo compartment and a cooling mode for removing heat from the cargo compartment. The cooling system includes first, second, and third refrigerant circuits, and the first refrigerant circuit includes a first heat exchanger that transfers heat of the refrigerant in the first refrigerant circuit to air, The second refrigerant circuit includes a second heat exchanger that transfers the heat of the air to the second refrigerant circuit. The third refrigerant circuit is connected to the compressor for increasing the pressure of the refrigerant in the third refrigerant circuit, and to the compressor to receive the refrigerant from the compressor, and is also connected to the first refrigerant circuit, and thus the first refrigerant circuit is connected. A condenser in which heat exchange occurs between the flowing refrigerant and the refrigerant flowing in the third refrigerant circuit; an expansion device that reduces the pressure of the refrigerant in the third refrigerant circuit; and the expander and the second refrigerant circuit And an evaporator which is configured to exchange heat between the refrigerant flowing through the second refrigerant circuit and the refrigerant flowing through the third refrigerant circuit. The refrigerant can move along the third refrigerant circuit under both heating and cooling modes, and movement between the first, second, and third refrigerant circuits under both modes can be prevented.

  In another embodiment, the present invention provides a cooling system that includes both a heating mode for heating a cargo compartment and a cooling mode for removing heat from the cargo compartment. The cooling system may include a first refrigerant circuit that passes through a compressor, an evaporator, an expansion device, and a condenser, and each mode operation of heating and cooling of the cooling system along the first refrigerant circuit. Sometimes a refrigerant flow path through which the refrigerant moves can be defined. The cooling system includes a second refrigerant circuit including a first refrigerant pump and passing through a condenser and a heat exchanger, and a third refrigerant circuit including a second refrigerant pump and passing through an evaporator and a heat exchanger. Further may be included. The second refrigerant pump can be operated during the heating mode and stopped during the cooling mode.

  According to the present invention, a method for operating a cooling system is also provided. In this method, the refrigerant is sent along the cooling circuit in the order of the compressor, the evaporator, the expansion device, and the condenser during the cooling mode operation of the cooling system, and the first pump is operated during the cooling mode operation of the cooling system. Circulating the refrigerant in the heat exchanger and transferring the heat of the cargo compartment to the refrigerant in the refrigerant circuit during the cooling mode operation of the cooling system. The method includes stopping the first pump during heating mode operation of the cooling system, sending refrigerant along the cooling circuit during heating mode operation of the cooling system, and operating the second pump during heating mode operation of the cooling system. Circulating the refrigerant through the heat exchanger in a heat exchange relationship with the refrigerant in the refrigerant circuit, and transferring the heat of the refrigerant in the refrigerant circuit to the luggage compartment during the heating mode operation of the cooling system.

  In this specification, “attached”, “coupled” or “coupled”, “supported”, “coupled” and variations thereof are used in their broader sense unless otherwise specified. Includes direct and indirect forms. Also, “connected” or “coupled” and “coupled” are not limited to their physical or mechanical aspects.

  In this specification, references to device or element orientation (eg, “middle”, “upper”, “lower”, “front”, “rear”, etc.) are intended only to simplify the description of the invention. It is intended to be used and is not intended to be limiting. Further, “first”, “second”, and “third” are used for explanation, and do not indicate or give relative importance or significance.

1A and 1B schematically illustrate a cooling system 10 according to some embodiments of the present invention. While the cooling system 10 is operated in air conditioning or cooling (A / C) mode, the CO ₂ exits the compressor 12 and then the first heat exchanger, which is an air-cooled gas cooler 14 in the embodiment of FIGS. 1A and 1B. (E.g. evaporator or condenser) . In the example of FIG. 1A, the refrigerant flow is indicated by three solid arrows. Depending on one or more operating conditions, the expected load in heating or cooling, and the type of refrigerant used, the refrigerant exiting the compressor 12 will be in a supercritical state. Although CO ₂ is referred to herein as a refrigerant, in other embodiments, such as, but not limited to, water, R12, engine coolant, any other organic refrigerant, R245fa, glycol, etc. may be used or substituted. Can be made. As shown in FIG. 1A, the fan 16, along adjacently or air flow passage opening is positioned on the heat exchanger 14, by shifting the refrigerant heat to the surrounding air flow provided by the fan 16, The heat of the heat exchanger 14 is radiated to the surrounding environment.

The refrigerant then enters a second heat exchanger (eg, an evaporator or condenser) , which in the example of FIG. 1A is a liquid cooled gas cooler 18 that is cooled by a hot second coolant loop 19. In the embodiment of FIG. 1A, liquid coolant flows through the second coolant loop 19 (possibly under a lower mass flow rate than that of the refrigerant from the heat exchanger 14) during system operation in A / C mode. Although the temperature is further reduced, the heat load of this heat exchanger 18 can be smaller than that of the heat exchanger 14. In another embodiment, the heat load of the heat exchanger 18, the refrigerant flows relative dimensions and cooling capacity of the heat exchanger 14 and heat exchanger 18, heat exchanger 14 and heat exchanger 18 to penetrate and traverse and mass flow rate of the coolant, whether fan 16 of heat exchanger 14, depending on the type or cooling capacity of the coolant used in heat exchanger 14 and heat exchanger 18, the heat load substantially heat exchanger 14 experiences May be equivalent or better.

As shown in FIG. 1A, the refrigerant leaving the heat exchanger 18 is further cooled before going to the expansion device or expansion valve 22, so that the heat exchanger (SLHX) 20 in the suction line (hereinafter also referred to as the heat exchanger 20). May flow into the high pressure side. The refrigerant exiting the expansion device or expansion valve 22 can flow into the air-to-refrigerant evaporator 24. A fan (not shown) may be positioned on the air to refrigerant evaporator 24 next to or along the airflow passage opening. In some embodiments, the fan is stopped while the cooling demand is low and / or the power consumption of the cooling system 10 is limited to improve efficiency. In the embodiment to or deceleration stops the fan, the heat load of the steam Hatsuki 24, than that of the liquid-refrigerant evaporator 26 for receiving the refrigerant from the heat exchanger 20 may be limited to a small value much.

In the case of the liquid-to-refrigerant evaporator 26, the refrigerant evaporates and passes through the liquid-to-refrigerant evaporator 26 through another low-temperature second coolant loop 28 (hereinafter also referred to as the low-temperature coolant loop 28). Then, heat energy is taken away from the flowing coolant (eg, glycol, water, R12, engine coolant, any organic refrigerant, R245fa, air, etc.) to cool the coolant. The air-to-refrigerant evaporator 24 can be located either upstream or downstream of the liquid-to-refrigerant evaporator 26. Although true for the arrangement of the heat exchanger 18 this regarding heat exchanger 14, while operating the cooling system 10 under A / C mode is by slowing or stagnation of the liquid in the heat exchanger 18 occurs It is desirable to avoid overheating and / or boiling.

The refrigerant leaving the liquid-to-refrigerant evaporator 26 can release heat to the high-pressure refrigerant in the suction line heat exchanger 20. An accumulator (not shown in FIGS. 1A to 2B) may be positioned on the low pressure side upstream of the heat exchanger 20 in the suction line. The accumulator can be a separate unit or can be directly connected to the heat exchanger 20 in the suction line.
In addition to the liquid-to-refrigerant evaporator 26, the cryogenic coolant loop 28 may include a cryogenic pump 29 for moving coolant through the liquid side of the liquid-to-refrigerant evaporator 26. While the heat of the coolant is transferred to the refrigerant in the liquid-to-refrigerant evaporator 26, there is a heat exchanger cooling core 30 that can be attached to the interior space or space 32 such as a truck or other automobile compartment. May be operated to dissipate heat from the cryogenic coolant loop 28. The heat exchanger cooling core 30 may be provided with an air operating device 34 such as a fan or blower that can cool the air in the passenger compartment 32 and / or dehumidify the air in the passenger compartment 32. In one embodiment, when the air flow through or across the heat exchanger cooling core 30 is cooled below the dew point, a small amount of coolant circulates through the second coolant loop 19 to cause a passenger compartment (three dotted arrows). The air flowing in) is reheated.

FIG. 1B illustrates the cooling system 10 during heating (HP) mode operation. As indicated by the three solid arrows, the refrigerant flows in the cooling system 10 in the same direction as previously described for A / C mode operation, but the fan 16 adjacent to the heat exchanger 14 is stopped and the high temperature cooling is performed. The liquid is pumped through the high temperature coolant loop 19 by the pump 35 to cool the refrigerant in the heat exchanger 18.
The cold pump 29 in the cold coolant loop 28 may be stopped and the air-to-refrigerant fan 34 may be operated. As a result, the heat of the high-temperature coolant can be transferred to the air flow in the heater core 36 of the air-to-coolant heat exchanger to further heat the interior of the passenger compartment 32. In order to improve the coefficient of performance (COP) when operating the cooling system 10 in the HP mode at low temperatures, the waste heat air stream 40 from the waste heat source 42, such as the cooling system 43 for the auxiliary power unit 44, is air to refrigerant. It can be sent through the evaporator 24.
In other embodiments, the waste heat source and / or another waste heat source 42 may, or alternatively, be a liquid-to-liquid heat exchanger evaporator or integrally stacked auxiliary power supply unit (APU) cooler and evaporator cooling. Heat may be provided to the material loop. In the latter case, utilizing the waste heat source 42 eliminates the need for an extra air-heated evaporator, and the “cooler” core can be an additional heat source for air in the space.

2A and 2B illustrate another embodiment of a cooling system 10 according to the present invention.
The cooling system shown in FIGS. 2A and 2B is similar in many respects to the previously described embodiment illustrated in FIGS. 1A and 1B, except for functional structural parts and elements that do not match between the two embodiments. For a detailed description (and alternatives) of the functional structure portions and elements of the embodiment of FIGS. 2A and 2B, reference is made to the previous description of the embodiment of FIGS. 1A and 1B.
FIG. 2A illustrates a simplified cooling system 10. In the cooling system 10 of this embodiment, the low temperature coolant loop 28, the high temperature coolant loop 19, and the coolant line 46 of the APU coolant system 43 are directly pumped to each other, All that is required is a liquid pump 47 (not including the APU coolant loop pump).

  As shown in FIG. 2A, a valve matrix 48 consisting of liquid valves 50, 52, 54, 56, 58, 59 is used to direct the coolant flow to the desired location under the HP and A / C modes. it can. Thereby, the air-to-refrigerant evaporator 24 can be made useless, and the functions of the cooler core 30 and the heater core 36 can be integrated as a heat exchanger in the form of a heater / cooler core 60.

For example, when A / C mode operation is performed, valve 59 (shown in dotted line) is opened, valves 56 and 58 (shown in solid line) are closed, valves 52 and 54 are opened, and valve 50 is closed. The coolant does not flow into the coolant loop 28 (which heats the liquid-to-refrigerant evaporator 26), so the coolant does not enter the heat exchanger 18 from the high temperature loop 19, while the coolant in the low temperature coolant loop 28. This heat is dissipated to the refrigerant in the liquid-to-refrigerant evaporator 26, and this coolant receives heat from the air flow passing through the heater / cooler core 60. Depending on the application, it may be better to pass a small amount of coolant through the valve 50 and the heat exchanger 18 because the refrigerant temperature will be lower than the ambient temperature and the COP of the system will improve.
As shown in FIG. 2B, during HP mode operation, valve 59 (shown in solid line) is closed or adjusted, valves 56 and 58 (shown in dotted line) are opened, valves 52 and 54 are closed, and valve 50 is opened. The coolant is sent to the liquid-to-refrigerant evaporator 26 and then circulated directly to the APU 44 without passing through the heater / cooler core 60, while the coolant in the hot loop 19 is circulated through the heat exchanger 18 to refrigerate. The heat is then released into the air stream passing through the heater / cooler core 60.

3A and 3B illustrate an alternative embodiment of the cooling system 10 according to the present invention. The cooling system shown in FIGS. 3A and 3B is similar in many respects to the embodiment illustrated above in FIGS. 1A-2B, and therefore, with the exception of functional structural portions and elements that do not match between the embodiments. For a detailed description (and alternative configurations) of the functional structure portions and elements of the embodiment of FIG. 3B, reference is made to the previous description of each embodiment of FIGS. 1A-2B.
The cooling system 10 of FIGS. 3A and 3B differs from the embodiment shown in FIGS. 1A and 1B in that the air-to-refrigerant evaporator 24 is removed and replaced with an air-heated coolant heat exchanger 66. An air-heated coolant heat exchanger 66 is added to the bypass line 68 within the low-temperature coolant loop 28, and a three-way valve 70 (or a series of two-way valves) causes the cooler core 30 and air-heated coolant heat exchange. Control the coolant flow through the vessel 66.

As shown in FIG. 3A, during A / C mode operation, the valve 70 sends coolant through the cooler core 30 rather than through the air-heated coolant heat exchanger 66, and thus the coolant flowing in the low temperature coolant loop 28. However, the heat of the air flow passing through the cooler core 30 can be absorbed. The operation of the hot loop can be substantially similar to that in the cooling system 10 shown in FIGS. 1A and 1B. The air-heated coolant heat exchanger 66 can be replaced with any other type of heat exchanger that utilizes other heat sources, such as, for example, a liquid waste heat stream from a generator.
As shown in FIG. 3B, during HP mode operation, the valve 70 sends coolant through the air-cooled coolant heat exchanger 66 rather than through the cooler core 30 and thus passes through the air-heated coolant heat exchanger 66. The heat of the ambient air is transferred to the coolant flowing in the low temperature coolant loop 28.

4A and 4B illustrate another embodiment of a cooling system 10 according to the present invention. The cooling system shown in FIGS. 4A and 4B is similar in many respects to the embodiment illustrated above in FIGS. 1A-3B, except for the functional structural parts and elements that do not match between the two embodiments. For a detailed description (and alternative configurations) of the functional structure portions and elements of the embodiment of 4A and 4B, reference is made to the previous description of each embodiment of FIGS. 1A-3B.
As shown in FIG. 4A and FIG. 4B, the cooling system 10 of this embodiment has both the heat exchanger 14 and the air-to-refrigerant evaporator 24 removed, and the functions of the cooler core 30 and the heater core 36 are as shown in FIG. An air-heated coolant heat exchanger 66, as discussed in connection with FIGS. 3A and 3B, is summarized as a heater / cooler core 60 as discussed in connection with FIG. The three-way valve 74 (or a series of two-way valves) provided in the high-temperature loop 19 and the three-way valve 78 provided in the low-temperature coolant loop 28 are connected to the heat in the high-temperature loop 19. It differs from the cooling system 10 shown in FIGS. 1A and 1B in that the coolant flow through the exchanger 60 and the air-cooled coolant heat exchanger 66 in the low temperature coolant loop 28 is controlled.
As shown in FIG. 4A, during the A / C mode operation, the valve 78 causes the coolant in the low temperature loop 19 to be sent through the heater / cooler core 60 which is a heat exchanger rather than the air-heated coolant heat exchanger 66. The vehicle compartment 32 is removed by heat and the valve 74 causes the coolant to flow from the hot loop 19 through the air-cooled coolant heat exchanger 66 rather than through the heater / cooler core 60, so that the coolant from the heat exchanger 18 The absorbed heat is released through the air-heated coolant heat exchanger 66 into the ambient air stream.
As shown in FIG. 4B, during HP mode operation, the coolant in the high temperature loop 19 is routed by the valve 74 through the heater / cooler core 60 rather than through the air-heated coolant heat exchanger 66, while the low temperature coolant. The coolant in the loop 28 is sent by the valve 78 through the air-cooled coolant heat exchanger 66 rather than the heater / cooler core 60, thus absorbing heat from the ambient air stream flowing through the heat exchanger 68.
Although the present invention has been described with reference to the embodiments, it should be understood that various modifications can be made within the present invention.

It is the schematic at the time of cooling mode operation | movement of the cooling system according to the Example of this invention. It is the schematic at the time of heating mode operation | movement of the cooling system of FIG. 1A. FIG. 6 is a schematic diagram of a cooling system according to another embodiment of the present invention during cooling mode operation. It is the schematic at the time of heating mode operation | movement of the cooling system of FIG. 2A. FIG. 6 is a schematic diagram of a cooling system according to another embodiment of the present invention during cooling mode operation. It is the schematic at the time of heating mode operation | movement of the cooling system of FIG. 3A. FIG. 6 is a schematic diagram of a cooling system according to another embodiment of the present invention during cooling mode operation. It is the schematic at the time of heating mode operation | movement of the cooling system of FIG. 4A.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cooling system 12 Compressor 14 1st heat exchanger 16 Fan 18 2nd heat exchanger 19 High temperature coolant loop 20 Heat exchanger in suction line 22 Expansion valve 24 Air-to-refrigerant evaporator 26 Liquid-to-refrigerant evaporator 28 2 Coolant loop 29 Low temperature pump 30 Heat exchanger cooling core 32 Car compartment 34 Air-to-refrigerant fan 35 Pump 36 Heater core 40 Waste heat air flow 42 Waste heat source 43 APU coolant system 44 Auxiliary power supply unit 46 Coolant line 48 Valve matrix 50, 52, 54, 56, 58, 59 Liquid valve 60 Heater / cooler core 66 Air-heated coolant heat exchanger 68 Bypass line 70, 78 Three-way valve

Claims (23)

A cooling system having both a heating mode for providing heat to the cargo compartment and a cooling mode for removing heat from the cargo compartment,
A first refrigerant circuit including a first heat exchanger for transferring heat of refrigerant in the first refrigerant circuit to air;
A second refrigerant circuit including a second heat exchanger for transferring the heat of air to the second refrigerant circuit as a second refrigerant circuit;
A third refrigerant circuit, a compressor that increases the pressure of the refrigerant in the third refrigerant circuit, a refrigerant that is connected to the compressor and receives heat of the compressor and moves through the first refrigerant circuit, and a third refrigerant circuit A condenser connected to the first refrigerant circuit so that heat exchange can occur with the moving refrigerant, an expansion device for reducing the pressure of the refrigerant in the third refrigerant circuit, and a second refrigerant connected to the expansion device An evaporator connected to the second refrigerant circuit so that heat exchange occurs between the refrigerant moving through the circuit and the refrigerant moving through the third refrigerant circuit, and the refrigerant is in the first and second operating modes. A third refrigerant circuit moving along a common direction in the three refrigerant circuit;
Including
A cooling system that prevents refrigerant from moving between the first refrigerant circuit, the second refrigerant circuit, and the third refrigerant circuit in both heating and cooling operation modes. The cooling system of claim 1, wherein the condenser is a liquid-cooled gas cooler. The cooling system according to claim 2, further comprising an air-cooled gas cooler connected in series to the liquid-cooled gas cooler and connected to at least one of the compressor and the expansion device. 2. The cooling system according to claim 1, wherein the evaporator is a liquid heating type evaporator. 5. The cooling system of claim 4, further comprising an air heated evaporator connected in series with the liquid heated evaporator and connected to at least one of the expansion device and the compressor. The cooling system of claim 1, further comprising a suction line heat exchanger connected to the condenser, expansion valve, evaporator, and compressor in the third refrigerant circuit. The cooling system according to claim 1, wherein the refrigerant in the third refrigerant circuit is carbon dioxide. The cooling system of Claim 1 which put together the 1st heat exchanger and the 2nd heat exchanger as a single heat exchanger. The cooling system of claim 1, further comprising a heat source separate from the first refrigerant circuit, the second refrigerant circuit, and the third refrigerant circuit for providing heat to the cooling system during heating mode operation. A cooling system having both a heating mode for heating the cargo compartment and a cooling mode for removing heat from the cargo compartment,
The first refrigerant circuit that passes through the compressor, the evaporator, the expansion device, and the condenser has a flow path for moving the refrigerant in the direction along the first refrigerant circuit during each operation in the heating mode and the cooling mode of the cooling system. A first refrigerant circuit defining;
A second refrigerant circuit including a first refrigerant pump and passing through a condenser and a heat exchanger;
Including a second refrigerant pump, including an evaporator and a third refrigerant circuit passing through the heat exchanger;
The second refrigerant pump is operated during the heating mode operation of the cooling system, and is stopped during the cooling mode operation of the cooling system;
Cooling system. The second refrigerant circuit is spaced from the first refrigerant circuit, thus preventing movement of the refrigerant between the first refrigerant circuit and the second refrigerant circuit, and the second refrigerant circuit is extended through the condenser, thus the first refrigerant circuit. The cooling system according to claim 10, wherein heat exchange occurs between the refrigerant moving through the first refrigerant circuit and the refrigerant moving through the second refrigerant circuit. The third refrigerant circuit is spaced from the first refrigerant circuit, thus preventing refrigerant movement between the first refrigerant circuit and the third refrigerant circuit, and the third refrigerant circuit is extended through the evaporator, thus the first refrigerant circuit. The cooling system according to claim 10, wherein heat exchange occurs between the refrigerant moving through the refrigerant circuit and the refrigerant moving through the third refrigerant circuit. The cooling system of claim 10, wherein the first refrigerant circuit includes a suction line heat exchanger. The heat exchanger includes a first heat exchanger core and a second heat exchanger core, the first heat exchanger core is associated with the second refrigerant circuit, and the second heat exchanger core is associated with the third refrigerant circuit. The cooling system of claim 10. The cooling system of claim 10, further comprising a heat source separate from the first refrigerant circuit, the second refrigerant circuit, and the third refrigerant circuit for providing heat to the cooling system during heating mode operation of the cooling system. The cooling system according to claim 10, wherein the evaporator is a liquid heating evaporator and the condenser is a liquid-cooled gas cooler. The cooling system of claim 16, further comprising an air-cooled gas cooler connected in series with the liquid-cooled gas cooler. The cooling system of claim 16, further comprising an air heated evaporator connected in series with the liquid heated evaporator. A method of operating a cooling system,
Sending the refrigerant along the refrigerant circuit in the direction through the compressor, evaporator, expansion device, condenser during cooling mode operation of the cooling system;
Circulating the refrigerant through the heat exchanger by operating the first pump during the cooling mode operation of the cooling system;
Transferring the heat of the luggage compartment to the refrigerant in the refrigerant circuit during the cooling mode operation of the cooling system;
Stopping the first pump during the heating operation mode of the cooling system;
Sending the refrigerant in the direction along the refrigerant circuit during the heating operation mode of the cooling system,
Circulating the refrigerant in a heat exchange relationship with the refrigerant in the refrigerant circuit through the heat exchanger by operating the second pump during the heating operation mode of the refrigerant circuit;
Transferring the heat of the refrigerant in the refrigerant circuit to the cargo compartment during the heating operation mode of the cooling system;
Including methods. 20. The method of claim 19, further comprising heating the refrigerant with a heat source separate from the refrigerant circuit during the heating mode of operation of the cooling system. 20. The method of claim 19, further comprising cooling the refrigerant using a suction line heat exchanger provided along the refrigerant circuit. 20. The method of claim 19, further comprising heating the refrigerant using an air heated evaporator and a liquid heated evaporator during a cooling mode of operation of the cooling system. 20. The method of claim 19, further comprising cooling the refrigerant using an air cooled condenser and a liquid cooled condenser during the heating mode of operation of the cooling system.

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