HVAC systems

Abstract

The secondary medium loop HVAC system includes an evaporator (50), a condenser (52), an expansion valve (56), and a compressor (54). A refrigerant loop (70) is in fluid communication with each of the evaporator, the condenser, and the expansion valve. An HVAC case (12) includes a first heat exchanger (20) and a second heat exchanger (22). A first cooling medium loop (80) is in fluid communication with the first heat exchanger, the second heat exchanger, and either the evaporator or the condenser. A valve system (110, 112, 114) is configured to control the flow of cooling medium through the first cooling medium loop. In a maximum heating mode, the valve system is configured to direct the cooling medium through the condenser, the first heat exchanger, and the second heat exchanger. In a maximum cooling mode, the valve system is configured to direct the cooling medium through the evaporator, the first heat exchanger, and the second heat exchanger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 268,538, filed February 25, 2022, U.S. Provisional Application No. 63 / 362,215, filed March 31, 2022, and U.S. Nonprovisional Application No. 17 / 941,396, filed September 9, 2022, the entire disclosures of which are incorporated herein by reference. [Technical field]

[0002] This disclosure relates to heating, ventilation, and air conditioning (HVAC) systems, such as secondary media loop HVAC systems. [Background technology]

[0003] This section provides background art related to the disclosure, but which is not necessarily prior art.

[0004] Heating, ventilation, and air conditioning (HVAC) systems are widely used to condition air for a variety of environments, such as vehicle passenger compartments. While existing HVAC systems are suitable for their intended uses, they remain subject to improvement. For example, HVAC systems that are more efficient and less complex than existing HVAC systems are desired. This disclosure includes improved HVAC systems, which are described in detail herein. Summary of the Invention

[0005] This section provides a summary of the disclosure and is not an exhaustive disclosure of the entire scope or all features of the disclosure.

[0006] The disclosure includes a secondary media loop HVAC system including an evaporator, a condenser, an expansion valve, and a compressor. A refrigerant loop is in fluid communication with each of the evaporator, the condenser, and the expansion valve. An HVAC case includes a first heat exchanger and a second heat exchanger. A first cooling media loop is in fluid communication with the first heat exchanger, the second heat exchanger, and either the evaporator or the condenser. A valve system is configured to control a flow of cooling media through the first cooling media loop. In a maximum heating mode, the valve system is configured to direct the cooling media through the condenser, the first heat exchanger, and the second heat exchanger. In a maximum cooling mode, the valve system is configured to direct the cooling media through the evaporator, the first heat exchanger, and the second heat exchanger.

[0007] The present disclosure further includes a secondary loop heating, ventilation, and air conditioning (HVAC) system including an evaporator, a condenser, an expansion valve, and a compressor. A refrigerant loop is in fluid communication with each of the evaporator, the condenser, and the expansion valve, and circulates a refrigerant therethrough. The HVAC case includes a first heat exchanger and a second heat exchanger. The HVAC case defines a face outlet, a foot outlet, and a defrost outlet. The first cooling medium loop is in fluid communication with the first heat exchanger, the second heat exchanger, and either the evaporator or the condenser, and circulates a cooling medium therethrough. The second cooling medium loop is in fluid communication with a radiator and either the evaporator or the condenser, and directs the cooling medium through the radiator. A valve system is configured to control the flow of the cooling medium through the first cooling medium loop and the second cooling medium loop. In a maximum heating mode, the valve system configures a first cooling medium loop to pass through the condenser, the first heat exchanger, and the second heat exchanger, and a second cooling medium loop to pass through the radiator and the evaporator. In a maximum cooling mode, the valve system configures a first cooling medium loop to pass through the evaporator, the first heat exchanger, and the second heat exchanger, and a second cooling medium loop to pass through the radiator and the condenser.

[0008] Further areas of applicability will become apparent from the description provided herein. This summary and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. [Brief description of the drawings]

[0009] The drawings described herein are only illustrative of selected embodiments and do not represent all practical possibilities and are not intended to limit the scope of the disclosure. [Figure 1] FIG. 1 illustrates a heating, ventilation, and air conditioning (HVAC) system including an exemplary secondary media loop according to this disclosure in a maximum heating mode. [Diagram 2] FIG. 2 shows the system of FIG. 1 in maximum cooling mode. [Diagram 3] FIG. 3 shows the system of FIG. 1 in heating, dehumidification and defrosting modes. [Figure 4] FIG. 4 shows the system of FIG. 1 in cooling, dehumidification, and temperature control modes. [Diagram 5] FIG. 5 shows the low coolant pressure drop in maximum heating mode. [Figure 6] FIG. 6 shows the low coolant pressure drop in maximum cooling mode. [Figure 7A] FIG. 7A is a perspective view of an exemplary dual zone heat exchanger according to this disclosure. [Figure 7B] FIG. 7B is a cross-sectional view taken along line 7B-7B of FIG. 7A.

[0010] Corresponding reference characters indicate corresponding parts throughout the several drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Example embodiments are more fully described with reference to the accompanying drawings.

[0012] Throughout this disclosure, the term "refrigerant" is used in accordance with the definition published by the American Society of Heating, Refrigeration and Air-Conditioning Engineers ("ASHRAE Terminology"), which defines "refrigerant" as: "A fluid used for heat transfer in a refrigeration system that absorbs heat at low fluid temperatures and pressures and releases heat at high fluid temperatures and pressures, usually involving a change in the state of the fluid."

[0013] Throughout this disclosure, the term "cooling medium" is used in accordance with the definition published by the American Society of Heating, Refrigeration and Air-Conditioning Engineers ("ASHRAE Terminology"), which defines a "cooling medium" as: "A single-phase fluid used to transfer heat from one location to another."

[0014] 1-6, a heating, ventilation, and air conditioning (HVAC) system including a secondary media loop in accordance with this disclosure is designated generally by the reference numeral 10. The HVAC system 10 includes an HVAC case 12. The HVAC case 12 is configured to be mounted in any suitable location to condition air for any suitable environment. In the illustrated example, the HVAC case 12 is particularly configured to condition air for a passenger compartment of any suitable vehicle. Suitable vehicles include, but are not limited to, passenger automobiles, mass transit vehicles, construction vehicles / equipment, commercial vehicles, military vehicles / equipment, marine vehicles, aircraft, and the like.

[0015] A first heat exchanger 20 and a second heat exchanger 22 are housed within the HVAC case 12. An airflow is generated by any suitable blower 30. The HVAC case 12 is configured to direct the airflow generated by the blower 30 to each of the first and second heat exchangers 20, 22. The airflow exits the HVAC case 12 through one or more of a face outlet 32, a foot outlet 34, and / or a defrost outlet 36 defined by the HVAC case 12. The airflow exiting the HVAC case 12 through the outlets 32, 34, and 36 is controlled by a face outlet control door 40, a foot outlet control door 42, and a defrost outlet control door 44, respectively.

[0016] The first heat exchanger 20 has a first height H1 that extends perpendicular to a first length of the first heat exchanger 20. The second heat exchanger 22 has a second height H2 that extends perpendicular to a second length of the second heat exchanger 22. The first and second heat exchangers 20, 22 are disposed in the HVAC case 12 such that the first height H1 of the first heat exchanger 20 is parallel to the second height H2 of the second heat exchanger 22. The first length of the first heat exchanger 20 extends parallel to the second length of the second heat exchanger 22. Thus, the first heat exchanger 20 and the second heat exchanger 22 are mounted in the same orientation in the HVAC case 12. The first heat exchanger 20 and the second heat exchanger 22 are the same size. Thus, the first height H1, the first length, and the first width of the first heat exchanger 20 are the same as the second height H2, the second length, and the second width of the second heat exchanger 22. The surface areas of the first heat exchanger 20 and the second heat exchanger 22 are also the same.

[0017] The HVAC system 10 further includes an evaporator 50 and a condenser 52. In the illustrated example, the evaporator 50 and the condenser 52 are positioned outside the HVAC case 12. The evaporator 50 may be any suitable evaporator, such as a water-cooled chiller. The condenser 52 may be any suitable condenser, such as a water-cooled condenser. The evaporator 50 and the condenser 52 are in fluid communication with the compressor 54 and the expansion valve 56 via a refrigerant loop 70. The refrigerant loop 70 includes any suitable piping or other tubes configured to transport any suitable refrigerant through each of the evaporator 50, the compressor 54, the condenser 52, and the expansion valve 56.

[0018] The HVAC system 10 further includes a first cooling medium loop 80. The first cooling medium loop 80 includes suitable passages, such as piping, for circulating a cooling medium. The first cooling medium loop 80 is in fluid communication with the first heat exchanger 20, the second heat exchanger 22, and either the evaporator 50 or the condenser 52 and is configured to circulate a cooling medium therethrough. The cooling medium is delivered to the evaporator 50 by a pump 82, and the cooling medium is delivered to the condenser 52 by a pump 84.

[0019] The HVAC system 10 further includes a radiator 90 and any suitable fan or other airflow circulating device 92. The radiator 90 is in fluid communication with a second cooling media loop 94. The second cooling media loop 94 includes any suitable tubing, such as piping, configured to traverse the evaporator 50 or condenser 52 in turn to direct cooling media to and from the radiator 90, as described herein.

[0020] The HVAC system 10 includes a valve system configured to control the flow of cooling medium through the first cooling medium loop 80 and the second cooling medium loop 94. The valve system may be configured to control the flow of cooling medium in any suitable manner, such as a plurality of valves arranged in series. In the illustrated example, the valve system includes a first valve 110, a second valve 112, a third valve 114, a fourth valve 116, and a fifth valve 118. The first valve 110 is located upstream of the first heat exchanger 20, and the cooling medium flowing from the evaporator 50 or the condenser 52 to the first heat exchanger 20 passes through the first valve 110. The second valve 112 is in direct fluid communication with both the first valve 110 and the second heat exchanger 22. The third valve 114 is located downstream of the first heat exchanger 20, and the cooling medium flowing from the first heat exchanger 20 is guided by the third valve 114 through or around the second heat exchanger 22.

[0021] A fourth valve 116 and a fifth valve 118 control the flow of cooling medium from the evaporator 50 or condenser 52 to the radiator 90. The valves 110, 112, 114, 116, and 118 are controlled in any suitable manner, such as via a controller 210. The control doors 40, 42, and 44 of the HVAC case 12 are also controlled by the controller 210. The speed of the compressor 54 and the speeds of the pumps 82, 84 are also controlled by the controller 210.

[0022] In this application, the term "controller" may be substituted for the term "circuitry." The term "controller" refers to, is part of, or includes a hardware processor (which may be shared, dedicated, or a group) for executing code, and a hardware memory (which may be shared, dedicated, or a group) that stores the code executed by the hardware processor. The code is configured to provide the functionality and features of the controller 210 described herein.

[0023] The term "hardware memory" is part of the term computer-readable medium. The term "computer-readable medium" does not encompass a transitory electrical or electromagnetic signal propagating through a medium such as on a carrier wave, and therefore the term "computer-readable medium" is interpreted as being tangible and non-transient (non-transient). Non-limiting examples of non-transient computer-readable media are non-volatile memory devices (e.g., flash memory devices, erasable programmable read-only memory devices, masked read-only memory devices, etc.), or volatile memory devices (e.g., static random access memory devices, dynamic random access memory devices, etc.), or magnetic storage media (e.g., analog or digital magnetic tape, hard disk drives, etc.), or optical storage media (e.g., CDs, DVDs, or Blu-ray disks, etc.).

[0024] The controller 210 is configured to operate the HVAC system 10 in a number of different modes. For example, the controller 210 is configured to operate the HVAC system 10 in a maximum heating mode (FIG. 1), a maximum cooling mode (FIG. 2), a heating, dehumidifying and defrosting mode (FIG. 3), or a cooling, dehumidifying and temperature control mode (FIG. 4). For situations where coolant side pressure drop is an issue, an extended heating mode (FIG. 5) and an extended cooling mode (FIG. 6) alternative embodiments are included.

[0025] For the maximum heating mode of FIG. 1, the controller 210 is configured to drive and control the plurality of valves 110, 112, 114, 116, 118 as shown in FIG. 1, so that the warm cooling medium, which is heated as a result of flowing across the condenser 52, flows across both the first heat exchanger 20 and the second heat exchanger 22 in series to heat the air going through the foot vent 34 to the passenger compartment of the vehicle and through the defrost vent 36 to the windshield. After passing through the second heat exchanger 22, the cooling medium is returned to the condenser 52. In the maximum heating mode of FIG. 1, the valve system is configured to guide the cooled cooling medium to the evaporator 50 and the radiator 90. Thus, in the maximum heating mode of FIG. 1, both the first heat exchanger 20 and the second heat exchanger 22 heat the air flow passing therethrough. The speed of the compressor 54 and the speed of the pumps 82, 84 are also controlled by the controller 210 to contribute to the maximum heating effect.

[0026] In the maximum cooling mode of FIG. 2, the controller 210 is configured to drive and control the valves 110, 112, 114, 116, and 118 as shown in FIG. 2. In the maximum cooling mode of FIG. 2, the cooling medium that has passed through the evaporator 50 and is cooled is sent to the first heat exchanger 20 by the first valve 110 and flows across the first heat exchanger 20. From the first heat exchanger 20, the cooled cooling medium is guided across the second heat exchanger 22 in series with the heat exchanger 20 by the third valve 114. The second valve 112 guides the cooling medium from the second heat exchanger 22 back to the evaporator 50. The cold cooling medium flowing through the first and second heat exchangers 20, 22 cools the flow of air that is supplied to the vehicle passenger compartment through the face outlet 32. The fourth and fifth valves 116, 118 are configured to guide the cooling medium between the condenser 52 and the radiator 90. 2, both the first heat exchanger 20 and the second heat exchanger 22 cool the airflow directed across them. The speed of the compressor 54 and the speeds of the pumps 82, 84 are also controlled by the controller 210 to contribute to maximum cooling effectiveness.

[0027] In the heating, dehumidifying, and defrosting modes of FIG. 3, the controller 210 is configured to drive and control the valves 110, 112, 114, 116, and 118 as shown in FIG. 3. In the heating, dehumidifying, and defrosting modes of FIG. 3, the first valve 110 guides the cooling medium heated by the condenser 52 to the first heat exchanger 20. The first valve 110 guides the cooling medium cooled by the evaporator 50 to the second heat exchanger 22. The cooling medium from the first heat exchanger 20 is guided back to the condenser 52 by the third valve 114. The cooling medium from the second heat exchanger 22 is guided back to the evaporator 50 by the third valve 114. The valves 116, 118 are configured to circulate the cooling medium between the evaporator 50 and the radiator 90. 3, the first heat exchanger 20 is at a relatively warm temperature, the second heat exchanger 22 is at a relatively cooler temperature, and the radiator 90 is exposed to the relatively cooler air outside the vehicle. The speed of the compressor 54 and the speeds of the pumps 82, 84 are also appropriately controlled by the controller 210 depending on the operating conditions.

[0028] The controller 210 is further configured to control the HVAC system 10 in cooling, dehumidification, and temperature control modes, as shown in the example of FIG. 4. In the cooling, dehumidification, and temperature control modes, the controller 210 is configured to control the valves 110, 112, 114, 116, and 118, as shown in FIG. 4. In the cooling, dehumidification, and temperature control mode of FIG. 4, the first, second, and third valves 110, 112, and 114 are controlled to the same states as in the heating, dehumidification, and defrost modes of FIG. 3. However, unlike the modes of FIG. 3, in the cooling, dehumidification, and temperature control mode of FIG. 4, the second cooling medium loop 94 is configured such that the cooling medium flows between the radiator 90 and the condenser 52. In the air conditioning mode of FIG. 4, the radiator 90 is exposed to relatively warm air outside the vehicle. The speed of the compressor 54 and the speeds of the pumps 82, 84 are also appropriately controlled by the controller 210 depending on the operating conditions.

[0029] 5, there may be some situations where it is desirable to minimize the pressure drop on the cooling medium side while taking advantage of the increased heat transfer area of ​​flowing hot cooling medium through both heat exchangers 20 and 22. In an alternative embodiment of the enhanced heating mode, the controller 210 drives the valves 110, 112, 114, 116, 118 as shown in FIG. 5 so that the warm cooling medium, which is heated as a result of flowing across the condenser 52, flows in parallel across both the first heat exchanger 20 and the second heat exchanger 22 to heat the airflow through the foot vent 34 to the passenger compartment of the vehicle and through the defrost vent 36 to the windshield. After flowing in parallel through the first heat exchanger 20 and the second heat exchanger 22, the cooling medium is returned to the condenser 52. In the alternative embodiment of the enhanced heating mode of FIG. 5, the valve system is configured to direct the cooled cooling medium to the evaporator 50 and the radiator 90. Thus, in the alternative embodiment of the enhanced heating mode of Figure 5, the cooling medium passes through the heat exchangers in parallel instead of in series as shown in the maximum heating mode of Figure 1, but both the first heat exchanger 20 and the second heat exchanger 22 heat the airflow passing therethrough. The speed of the compressor 54 and the speeds of the pumps 82, 84 are also controlled by the controller 210 to contribute to the enhanced heating effect.

[0030] Referring to Fig. 6, there may be some situations where it is desirable to minimize the pressure drop on the cooling medium side while taking advantage of the increased heat transfer area by flowing a low temperature cooling medium through both heat exchangers 20 and 22. In this alternative embodiment of the enhanced cooling mode of Fig. 6, the controller 210 is configured to drive and control the valves 110, 112, 114, 116, and 118 as shown in Fig. 6. In the alternative embodiment of the enhanced cooling mode of Fig. 6, the cooling medium that has passed through the evaporator 50 and has been cooled is directed by the first valve 110 to the first heat exchanger 20 and flows across the first heat exchanger 20. In parallel with the flow through the first heat exchanger 20, the cooled cooling medium is directed by the first valve 110 and the valve 112 across the second heat exchanger 22. The valve 114 directs the cooling medium from the first heat exchanger 20 and the second heat exchanger 22 back to the evaporator 50. The cold cooling medium flowing through the first and second heat exchangers 20, 22 cools the airflow that is provided to the vehicle passenger compartment through the face outlet 32. The fourth and fifth valves 116, 118 are configured to direct the cooling medium between the condenser 52 and the radiator 90. Thus, in the enhanced cooling mode alternative embodiment of FIG. 6, the flow of cooling medium through the heat exchangers 20 and 22 occurs in parallel, rather than in series as shown in the maximum cooling mode of FIG. 2, but both the first heat exchanger 20 and the second heat exchanger 22 cool the airflow that crosses the first heat exchanger 20 and the second heat exchanger 22. The speed of the compressor 54 and the speed of the pumps 82, 84 are also controlled by the controller 210 to contribute to the improved cooling effect of the alternative embodiment.

[0031] 7A and 7B, the first heat exchanger 20 and the second heat exchanger 22 may be combined as a heat exchanger assembly 310. The heat exchanger assembly 310 performs the functions of both the first heat exchanger 20 and the second heat exchanger 22. Specifically, the heat exchanger assembly 310 includes a first inlet tank 312A disposed adjacent to a second inlet tank 312B. The first outlet tank 314A is disposed adjacent to a second outlet tank 314B. The first inlet pipe 320A is in fluid communication with the first inlet tank 312A and delivers the cooling medium to the first inlet tank 312A. The second inlet pipe 320B is in fluid communication with the second inlet tank 312B and delivers the cooling medium to the second inlet tank 312B. The first outlet pipe 322A is in fluid communication with the first outlet tank 314A and allows the cooling medium to flow out of the first outlet tank 314A. The second outlet pipe 322B is in fluid communication with the second outlet tank 314B and allows the cooling medium to flow out of the second outlet tank 314B.

[0032] Extending from the first inlet tank 312A to the first outlet tank 314A is a first row of tubes 330A. Extending from the second inlet tank 312B to the second outlet tank 314B is a second row of tubes 330B. The first row of tubes 330A passes coolant from the first inlet tank 312A to the first outlet tank 314A. The second row of tubes 330B passes coolant from the second inlet tank 312B to the second outlet tank 314B. A first end plate 340 and a second end plate 342 are on opposite sides of the first row of tubes 330A and the second row of tubes 330B and hold all of the first and second rows of tubes 330A, 330B (as well as the tanks 312A, 312B, 314A, 314B) together in an assembly as shown. The first row of the plurality of tubes 330A, when a cooling medium passes through them, effectively functions as the first heat exchanger 20 described above. The second row of the plurality of tubes 330B, when a cooling medium passes through them, effectively functions as the second heat exchanger 22 described above. Thus, the heat exchanger assembly 310 can replace the first heat exchanger 20 and the second heat exchanger 22 along the first cooling medium loop 80.

[0033] The above description of the embodiments has been provided for purposes of illustration and description. This disclosure is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but may be interchangeable, where applicable, and may be used in selected embodiments even if not specifically shown or described. The same may be varied in many ways. Such variations should not be considered departures from the disclosure, and all such modifications are intended to be included within the scope of this disclosure.

[0034] The exemplary embodiments are provided so that this disclosure is thorough and will fully convey its scope to those skilled in the art. Many specific details are set forth, such as examples of specific components, devices, and methods, to provide a thorough understanding of the embodiments of this disclosure. It will be apparent to those skilled in the art that specific details need not be employed, and that the exemplary embodiments can be implemented in many different forms, none of which should be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes (steps in a method), well-known device structures, and well-known technologies are not described in detail.

[0035] The terms used in this specification are for the purpose of describing particular exemplary embodiments only and are not intended to be limiting. As used in this specification, the singular (definite and indefinite articles) are intended to include the plural unless the context clearly indicates otherwise. The terms "comprises," "has," "includes," and "has" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The steps, processes, and operations of the methodologies described in this specification should not be construed as necessarily requiring the particular order described or illustrated, unless specifically identified as such. It should also be understood that additional or alternative steps may be employed.

[0036] When an element or layer is referred to as being "on," "coupled," "connected," or "coupled," it may be directly coupled, connected, or coupled to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly coupled" to another element or layer, there are no intervening elements or layers. Other words used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] Terms such as first, second, third, etc. may be used in this specification to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. "First," "second," and other numerical terms, as used herein, do not imply a sequence or order unless clearly indicated by the context. Thus, a first "element, component, region, layer, or section" described below can be referred to as a second "element, component, region, layer, or section" without departing from the teachings of the exemplary embodiments.

[0038] Spatially relative terms such as "inside," "outside," "back," "bottom," "low," "top," "top," and the like are utilized herein to facilitate the description of the relationship of one element or feature to another element or feature as illustrated. Spatially relative terms may be intended to encompass various orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned upside down, an element described as "below" or "behind" another element or feature would be oriented "above" the other element or feature. Thus, the illustrated term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used in this specification interpreted accordingly.

Claims

1. An evaporator (50), a condenser (52), an expansion valve (56), and a compressor (54), a refrigerant loop (70) in fluid communication with each of the evaporator, the condenser, and the expansion valve for circulating a refrigerant therethrough; an HVAC case (12) including a first heat exchanger (20) and a second heat exchanger (22); a first cooling medium loop (80) in fluid communication with the first heat exchanger, the second heat exchanger, and either the evaporator or the condenser for circulating a cooling medium therethrough; and a valve system (110, 112, 114) configured to control a flow of coolant through the first coolant loop; the valve system is configured to direct a cooling medium through the condenser, the first heat exchanger, and the second heat exchanger in a maximum heating mode; The HVAC system, wherein the valve system is configured to direct a cooling medium through the evaporator, the first heat exchanger, and the second heat exchanger in a maximum cooling mode.

2. the first heat exchanger has a first height and a first length extending perpendicular to the first height; the second heat exchanger has a second height and a second length extending perpendicular to the second height; The HVAC system of claim 1 , wherein the first elevation is parallel to the second elevation.

3. 3. The HVAC system of claim 2, wherein the first heat exchanger and the second heat exchanger are the same size.

4. The HVAC system according to any one of claims 1 to 3, wherein the evaporator, the condenser, the expansion valve, and the compressor are positioned outside the HVAC case.

5. The HVAC system according to any one of claims 1 to 4, wherein the HVAC case defines a defroster outlet (36), a face outlet (32), and a foot outlet (34).

6. 6. The HVAC system of claim 1, wherein the evaporator is a water-cooled chiller and the condenser is a water-cooled condenser.

7. 7. The HVAC system of claim 1, wherein the valve system includes a first valve (110) along the first cooling medium loop upstream of the first heat exchanger, the first valve configured to direct cooling medium from the condenser to the first heat exchanger in the maximum heating mode, and the first valve configured to direct cooling medium from the evaporator to the first heat exchanger in the maximum cooling mode.

8. 8. The HVAC system of claim 7, wherein the valve system further comprises a second valve (112) along the first cooling medium loop downstream of the second heat exchanger, the second valve configured to return the cooling medium from the second heat exchanger to the condenser in the maximum heating mode, and the second valve configured to return the cooling medium from the second heat exchanger to the evaporator in the maximum cooling mode.

9. 9. The HVAC system of claim 8, wherein the valve system further includes a third valve (114) along the first cooling medium loop between the first heat exchanger and the second heat exchanger, the third valve configured to direct cooling medium from the first heat exchanger to the second heat exchanger in both the maximum heating mode and the maximum cooling mode.

10. 10. The HVAC system of claim 9, further comprising an HVAC control device (210) configured to control actuation of the first valve, the second valve, and the third valve in the maximum heating mode or the maximum cooling mode.

11. In heating mode: the valve system is configured to route warm cooling medium from the condenser to both the first heat exchanger and the second heat exchanger in parallel and then back to the condenser to heat a flow of air that is routed through a foot outlet of the HVAC case to a passenger compartment of the vehicle and through a defrost outlet to a windshield; The HVAC system of claim 1 , wherein the valve system is configured to direct a cooled cooling medium to the evaporator and to a radiator.

12. In cooling mode: the valve system is configured to route cooled cooling medium from the evaporator to both the first heat exchanger and the second heat exchanger in parallel and then back to the evaporator to cool a flow of air routed through a face outlet of the HVAC case to a passenger compartment of the vehicle; The HVAC system of claim 1 , wherein the valve system is configured to direct a cooling medium between the condenser and a radiator.

13. Further, a heat sink (90), and a second cooling medium loop (94) in fluid communication with the radiator and either the evaporator or the condenser for directing the cooling medium through the radiator; In the maximum heating mode, the cooling medium flows between the radiator and the evaporator, The HVAC system of any one of claims 1 to 12, wherein in the maximum cooling mode, the cooling medium flows between the radiator and the condenser.

14. the valve system is configured to, in heating, dehumidification, and defrosting modes, direct cooling medium from the condenser through the first heat exchanger and back to the condenser and from the evaporator through the second heat exchanger and back to the evaporator; 2. The HVAC system of claim 1, wherein the valve system is configured to direct cooling medium from the condenser through the first heat exchanger and back to the condenser and from the evaporator through the second heat exchanger and back to the evaporator in cooling, dehumidification, and temperature control modes.

15. The HVAC system of any one of claims 1 to 14, wherein the first heat exchanger and the second heat exchanger are combined into a single assembly.

16. the first heat exchanger includes a plurality of first cooling medium tubes in fluid communication with a first inlet tank (312A) and a first outlet tank (314A); the second heat exchanger includes a plurality of second cooling medium tubes in fluid communication with a second inlet tank (312B) and a second outlet tank (314B); The HVAC system of any one of claims 1 to 15, further comprising a first end plate (340) and a second end plate (342) for fixing the first cooling medium tubes and the second cooling medium tubes adjacent to each other.

17. An evaporator (50), a condenser (52), an expansion valve (56), and a compressor (54), a refrigerant loop (70) in fluid communication with each of the evaporator, the condenser, and the expansion valve for circulating a refrigerant therethrough; an HVAC case (12) including a first heat exchanger (20) and a second heat exchanger (22) and defining a face outlet (32), a foot outlet (34), and a defrost outlet (36); radiator (90), a first cooling medium loop (80) in fluid communication with either the first heat exchanger, the second heat exchanger, and the evaporator or the condenser for circulating a cooling medium therethrough; a second cooling medium loop (94) in fluid communication with the radiator and either the evaporator or the condenser, for directing the cooling medium through the radiator; and a valve system (110, 112, 114, 116, 118) configured to control the flow of coolant through the first coolant loop and the second coolant loop; the valve system, in a maximum heating mode, configures the first cooling medium loop to pass through the condenser, the first heat exchanger, and the second heat exchanger, and configures the second cooling medium loop to pass through the radiator and the evaporator; The valve system configures the first cooling medium loop to pass through the evaporator, the first heat exchanger, and the second heat exchanger, and configures the second cooling medium loop to pass through the radiator and the condenser in a maximum cooling mode.

18. the first heat exchanger has a first height and a first length extending perpendicular to the first height; the second heat exchanger has a second height and a second length extending perpendicular to the second height; 20. The HVAC system of claim 17, wherein the first elevation is parallel to the second elevation.

19. 20. The HVAC system of claim 18, wherein the first heat exchanger and the second heat exchanger are identical in size.

20. 20. The HVAC system of claim 17, wherein the evaporator, the condenser, the expansion valve, and the compressor are positioned outside the HVAC case.

21. the valve system is configured to, in heating, dehumidification, and defrosting modes, direct cooling medium from the condenser through the first heat exchanger and back to the condenser, and from the evaporator through the second heat exchanger and back to the evaporator, the radiator, and between the evaporator; The HVAC system of any one of claims 17 to 20, wherein the valve system is configured to, in cooling, dehumidification and temperature control modes, return the cooling medium from the condenser through the first heat exchanger to the condenser, and from the evaporator through the second heat exchanger to between the evaporator, the radiator and the condenser.

22. the first heat exchanger includes a plurality of first cooling medium tubes in fluid communication with a first inlet tank (312A) and a first outlet tank (314A); the second heat exchanger includes a plurality of second cooling medium tubes in fluid communication with a second inlet tank (312B) and a second outlet tank (314B); The HVAC system of any one of claims 17 to 21, further comprising a first end plate (340) and a second end plate (342) for fixing the first cooling medium tube and the second cooling medium tube adjacent to each other.

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