FLOW CIRCUITRY AND VALVING FOR REVERSIBLE HVAC HEAT EXCHANGE CONFIGURATIONS
An HVAC system can include a multiport valve for controlling refrigerant circulation that permits refrigerant flow in a first direction through an interior heat exchanger and in a first direction through an auxiliary heat exchanger and at least one additional configuration in which refrigerant flows in a second direction through at least one of the interior heat exchanger and the auxiliary heat exchanger. The at least one configuration can include a second configuration in which refrigerant flows in the first direction through the interior heat exchanger and in the second direction through the auxiliary heat exchanger and a third configuration in which refrigerant flows in the second direction through the interior heat exchanger and the auxiliary heat exchanger.
Heating, ventilation, and air conditioning (HVAC) systems are employed in a wide variety of climate control applications. In at least some such applications, it may be desirable to provide a multiplicity of climate control functions for the same space at different times, such as heating the space, cooling the space, and dehumidifying the space. Some applications may present unique challenges in this regard, for example, relating to packaging, capacity, complexity, and performance.
SUMMARYDisclosed herein are exemplary HVAC systems, components, and operational techniques that may be advantageously employed to provide improved HVAC systems and operation.
An HVAC system can include an interior heat exchanger that receives an air stream, facilitates heat transfer between the air stream and a refrigerant, and discharges the air stream; an auxiliary heat exchanger that receives the air stream discharged from the interior heat exchanger and facilitates further heat transfer between the air stream and the refrigerant, and dischargers the air stream; and a multiport valve that controls refrigerant circulation through the interior heat exchanger and the auxiliary heat exchanger. The multiport valve can have a first configuration in which refrigerant flows in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger, wherein the first refrigerant flow direction is a cross-counter flow direction relative to airflow through a respective heat exchanger. The multiport valve can have at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger, wherein the second refrigerant flow direction is a cross-parallel flow direction relative to airflow through the respective heat exchanger.
The at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger can further include a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger and a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger. The first configuration can be a heating configuration, the second configuration can be a dehumidifying configuration, and the third configuration can be a cooling configuration. In the first/heating configuration refrigerant can flow first through the auxiliary heat exchanger and then through the interior heat exchanger, and in the third/cooling configuration refrigerant can flow first through the interior heat exchanger and then through the auxiliary heat exchanger. The multiport valve can further have at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger.
A multiport valve for controlling refrigerant circulation through an interior heat exchanger and an auxiliary heat exchanger of an HVAC system can include a first configuration that permits refrigerant flow in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger and at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger. The at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger can include a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger and a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger.
The multiport valve can have at least six ports. In the first configuration a hot gas port can be coupled to a first port of the auxiliary heat exchanger, a second port of the auxiliary heat exchanger can be coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger can be coupled to a liquid refrigerant line of the HVAC system. The first configuration can be a heating configuration. In the second configuration, a hot gas port can be coupled to a first port of the auxiliary heat exchanger, a suction line can be coupled to a second port of the auxiliary heat exchanger, a liquid refrigerant line can be coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger can be coupled to an expansion valve of the HVAC system, thereby reversing refrigerant flow through the interior heat exchanger relative to the first configuration while maintaining refrigerant flow in the first refrigerant flow direction through the auxiliary heat exchanger. The second configuration can be a dehumidifying configuration. In the third configuration, a second port of the interior heat exchanger can be coupled to an expansion valve of the HVAC system, a first port of the interior heat exchanger can be coupled to a second port of the auxiliary heat exchanger, and a first port of the auxiliary heat exchanger can be coupled to a suction line, thereby reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger relative to the first configuration. The third configuration can be a cooling configuration.
The multiport valve can further have at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger.
A method of operating an HVAC system to achieve a plurality of operating modes can include: actuating a multiport valve to a first position corresponding to a first operating mode, the first position permitting refrigerant flow in a first refrigerant flow direction through an interior heat exchanger that also receives an airstream from an interior space and in the first refrigerant flow direction through an auxiliary heat exchanger that receives the airstream from the interior heat exchanger and returns it to the interior space; actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger. Actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger, can further include actuating the multiport valve to a second position corresponding to a second operating mode, the second position reversing refrigerant flow through the interior heat exchanger and actuating the multiport valve to a third position corresponding to a third operating mode, the third position reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger. The first operating mode can be a heating mode, the second operating mode can be a dehumidifying mode, and the third operating mode can be a cooling mode. The first refrigerant flow direction can be a cross-counter flow direction relative to airflow through a respective heat exchanger and reversed refrigerant flow can be in a cross-parallel flow direction relative to airflow through a respective heat exchanger.
In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts. As part of this description, some of this disclosure's drawings represent structures and devices in block diagram form for sake of simplicity. In the interest of clarity, not all features of an actual implementation are described in this disclosure. Moreover, the language used in this disclosure has been selected for readability and instructional purposes, has not been selected to delineate or circumscribe the disclosed subject matter. Rather the appended claims are intended for such purpose.
Various embodiments of the disclosed concepts are illustrated by way of example and not by way of limitation in the accompanying drawings in which like references indicate similar elements. For simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth to provide a thorough understanding of the implementations described herein. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant function being described. References to “an,” “one,” or “another” embodiment in this disclosure are not necessarily to the same or different embodiment, and they mean at least one. A given figure may be used to illustrate the features of more than one embodiment, or more than one species of the disclosure, and not all elements in the figure may be required for a given embodiment or species. A reference number, when provided in a drawing, refers to the same element throughout the several drawings, though it may not be repeated in every drawing. The drawings are not to scale unless otherwise indicated, and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.
As illustrated in
Some HVAC systems, for example automotive HVAC systems, may also include an auxiliary interior heat exchanger 120. In conventional automobile HVAC systems, this interior heat exchanger 120 may be a heater core, through which engine coolant warmed by waste heat from an internal combustion engine may be passed. In such systems, the above-described vapor compression system may be used for cooling, while the auxiliary heat exchanger may be used for heating. In some cases, such as dehumidifying (e.g., defogging windows), both systems may be operable simultaneously as further described below with reference to
The above description is provided primarily for context. Many variations on these concepts might be used in given system. For example, depending on the refrigerant, working temperatures, and working pressures, the “condenser” coil might not actually cool the refrigerant sufficiently to induce a phase change. In such applications, “gas cooler” might be a more appropriate term than “condenser,” although the basic heat transfer arrangement described above would still apply. Similarly, the liquid to vapor phase change associated with the expansion valve and/or evaporator may occur at different points in the loop and/or may not occur at all in certain conditions. In such condition “evaporator” may not be the most precise term for the cold side heat exchanger. Nonetheless, such terms are in wide use in the art, and are used here as an aid to understanding.
In the illustrated heating configuration, air and refrigerant flow through both interior heat exchanger is in a cross-counter flow configuration, which is illustrated in greater detail in
In at least some embodiments, a cross-counter flow configuration may provide more effective operation in heating modes via improved heat transfer. Thus, it may be desirable for the configurations illustrated in
Variations of the above-described modes are also possible. For example, in some cases an alternative or additional cooling mode could be configured in which auxiliary heat exchanger is bypassed, providing only one interior heat exchanger/evaporator for the cooling operation. In other cases, an additional or alternative heating mode could be provided in which one of interior heat exchanger 318 or auxiliary heat exchanger 320 is bypassed. Likewise, the dehumidification mode may additionally or alternatively use or bypass the exterior heat exchanger (not shown in
With reference to
The foregoing describes exemplary embodiments of HVAC systems that employ multiple interior heat exchangers and associated valving to allow for reversible refrigerant flow to accommodate various operating modes. Although numerous specific features and various embodiments have been described, it is to be understood that, unless otherwise noted as being mutually exclusive, the various features and embodiments may be combined various permutations in a particular implementation. Thus, the various embodiments described above are provided by way of illustration only and should not be constructed to limit the scope of the disclosure. Various modifications and changes can be made to the principles and embodiments herein without departing from the scope of the disclosure and without departing from the scope of the claims.
Claims
1. An HVAC system comprising:
- an interior heat exchanger that receives an air stream, facilitates heat transfer between the air stream and a refrigerant, and discharges the air stream;
- an auxiliary heat exchanger that receives the air stream discharged from the interior heat exchanger and facilitates further heat transfer between the air stream and the refrigerant, and dischargers the air stream; and
- a multiport valve that controls refrigerant circulation through the interior heat exchanger and the auxiliary heat exchanger, the multiport valve having: a first configuration in which refrigerant flows in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger, wherein the first refrigerant flow direction is a cross-counter flow direction relative to airflow through a respective heat exchanger; and at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger, wherein the second refrigerant flow direction is a cross-parallel flow direction relative to airflow through the respective heat exchanger.
2. The HVAC system of claim 1 wherein the at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
- a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger; and
- a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger.
3. The HVAC system of claim 2 wherein the first configuration is a heating configuration, the second configuration is a dehumidifying configuration, and the third configuration is a cooling configuration.
4. The HVAC system of claim 3 wherein in the first/heating configuration refrigerant flows first through the auxiliary heat exchanger and then through the interior heat exchanger and in the third/cooling configuration refrigerant flows first through the interior heat exchanger and then through the auxiliary heat exchanger.
5. The HVAC system of claim 1 wherein the multiport valve has at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger.
6. A multiport valve for controlling refrigerant circulation through an interior heat exchanger and an auxiliary heat exchanger of an HVAC system, the multiport valve having:
- a first configuration that permits refrigerant flow in a first refrigerant flow direction through the interior heat exchanger and in a first refrigerant flow direction through the auxiliary heat exchanger; and
- at least one additional configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger.
7. The multiport valve of claim 6 wherein the at least one configuration in which refrigerant flows in a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
- a second configuration in which refrigerant flows in the first refrigerant flow direction through the interior heat exchanger and in the second refrigerant flow direction through the auxiliary heat exchanger; and
- a third configuration in which refrigerant flows in the second refrigerant flow direction through the interior heat exchanger and the auxiliary heat exchanger.
8. The multiport valve of claim 7 wherein the multiport valve has at least six ports.
9. The multiport valve of claim 8 wherein in the first configuration a hot gas port is coupled to a first port of the auxiliary heat exchanger, a second port of the auxiliary heat exchanger is coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger is coupled to a liquid refrigerant line of the HVAC system.
10. The multiport valve of claim 9 wherein the first configuration is a heating configuration.
11. The multiport valve of claim 8 wherein in the second configuration, a hot gas port is coupled to a first port of the auxiliary heat exchanger, a suction line is coupled to a second port of the auxiliary heat exchanger, a liquid refrigerant line is coupled to a first port of the interior heat exchanger, and a second port of the interior heat exchanger is coupled to an expansion valve of the HVAC system, thereby reversing refrigerant flow through the interior heat exchanger relative to the first configuration while maintaining refrigerant flow in the first refrigerant flow direction through the auxiliary heat exchanger.
12. The multiport valve of claim 11 wherein the second configuration is a dehumidifying configuration.
13. The multiport valve of claim 8 wherein in the third configuration, a second port of the interior heat exchanger is coupled to an expansion valve of the HVAC system, a first port of the interior heat exchanger is coupled to a second port of the auxiliary heat exchanger, and a first port of the auxiliary heat exchanger is coupled to a suction line, thereby reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger relative to the first configuration.
14. The multiport valve of claim 13 wherein the third configuration is a cooling configuration.
15. The multiport valve of claim 6 further having at least one configuration in which refrigerant flow bypasses at least one of the interior heat exchanger and the auxiliary heat exchanger.
16. A method of operating an HVAC system to achieve a plurality of operating modes, the method comprising:
- actuating a multiport valve to a first position corresponding to a first operating mode, the first position permitting refrigerant flow in a first refrigerant flow direction through an interior heat exchanger that also receives an airstream from an interior space and in the first refrigerant flow direction through an auxiliary heat exchanger that receives the airstream from the interior heat exchanger and returns it to the interior space;
- actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger.
17. The method of claim 16 wherein actuating the multiport valve to at least one other position corresponding to at least one other operating mode, the at least one other position reversing refrigerant flow to a second refrigerant flow direction through at least one of the interior heat exchanger and the auxiliary heat exchanger further comprises:
- actuating the multiport valve to a second position corresponding to a second operating mode, the second position reversing refrigerant flow through the interior heat exchanger; and
- actuating the multiport valve to a third position corresponding to a third operating mode, the third position reversing refrigerant flow through the interior heat exchanger and the auxiliary heat exchanger.
18. The method of claim 17 wherein the first operating mode is a heating mode, the second operating mode is a dehumidifying mode, and the third operating mode is a cooling mode.
19. The method of claim 18 wherein the first refrigerant flow direction is a cross-counter flow direction relative to airflow through a respective heat exchanger and reversed refrigerant flow is in a cross-parallel flow direction relative to airflow through a respective heat exchanger.
Type: Application
Filed: Jun 8, 2022
Publication Date: Dec 14, 2023
Inventors: Scott Stephen Wujek (San Jose, CA), Paul D. Yeomans (Aptos, CA), Alen Milosevic (Santa Clara, CA)
Application Number: 17/806,016