System for combined space and water heating and associated methods

Abstract

Systems and methods for selectively heating water and conditioning a space are disclosed. The systems include a compressor, an outdoor heat exchanger, an air-handling heat exchanger, a water-heating heat exchanger, and a valve assembly having one or more controllable valves configured to direct refrigerant to one or both of the heat exchangers. The valve assembly may include solenoid valves, a single reversing valve, or cascaded reversing valves. A controller regulates refrigerant routing among operating modes including water-heating-only, air-heating-only, water-heating and air-heating, air-cooling- only, and air-cooling and water-heating. A heat exchanger is used to transfer heat to water within or external to a water heater tank. In retrofit applications, a refrigerant-management module enables heat-pump water heating without replacing an existing HVAC unit. The systems advantageously enable heat-pump water heating even in spaces in which a heat pump water heater would otherwise not fit or would otherwise not be installed.

Description

COE-034-WO (92575-3133)SYSTEM FOR COMBINED SPACE AND WATER HEATING AND ASSOCIATED METHODSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of US provisional application No. 63 / 752,496, filed January 31, 2025, which is hereby incorporated by reference herein in its entirety.FIELD

[0002] The present disclosure is generally in the field of water heaters, and more particularly related to heat pump water heaters with space conditioning functionality.BACKGROUND

[0003] Heat pump water heaters are generally used to provide a supply of hot water while consuming less than half as much energy7as passive electric water heaters, which rely on an electric heating element to heat a volume of water. The heat pump blows relatively warm ambient air over an evaporator to warm a refrigerant which is then compressed by a compressor to increase its temperature and pressure. The refrigerant is then passed through a heat exchanger, such as a coil surrounding a water tank in a water heater, which results in transferring the thermal energy' from the refrigerant to another medium, such as water in the water heater tank, before passing through an expansion device and returning to the evaporator.

[0004] The improved efficiency of heat pump water heaters has resulted in a growing trend towards replacing electric water heaters with heat pump water heaters.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The detailed description is set forth with reference to the accompanying drawings. The use of the same reference numerals may indicate similar or identical items. Various embodiments may utilize elements and / or components other than those illustrated in the drawings, and some elements and / or components may not be present in various embodiments. Elements and / or components in the figures are not necessarily drawn toCOE-034-WO (92575-3133)scale. Throughout this disclosure, depending on the context, singular and plural terminology may be used interchangeably.

[0006] FIG. 1 depicts a system for selectively heating water or conditioning a space in accordance with the present disclosure.

[0007] FIG. 2 depicts a system for selectively heating water or conditioning a space in accordance with the present disclosure.

[0008] FIG. 3 depicts a brazed-plate heat exchanger in accordance with the present disclosure.

[0009] FIG. 4A depicts a system operating in a water-heating-only mode in accordance with the present disclosure.

[0010] FIG. 4B depicts the system schematic of FIG. 4A with indoor and outdoor components identified in accordance with the present disclosure.

[0011] FIG. 5A depicts a system operating in a water-heating-only mode in accordance with the present disclosure.

[0012] FIG. 5B depicts a system operating in an air-heating-only mode in accordance with the present disclosure.

[0013] FIG. 5C depicts a system operating in a water-heating and air-heating mode in accordance with the present disclosure.

[0014] FIG. 5D depicts a system operating in an air-cooling-only mode in accordance with the present disclosure.

[0015] FIG. 5E depicts a system operating in an air-cooling and water-heating mode in accordance with the present disclosure.

[0016] FIG. 6A depicts a cascaded reversing-valve system operating in a water-heating-only mode in accordance with the present disclosure.

[0017] FIG. 6B depicts a cascaded reversing-valve system operating in a water-heating and air-heating mode in accordance with the present disclosure.

[0018] FIG.6C depicts a cascaded reversing-valve system operating in an air-cooling and water-heating mode in accordance with the present disclosure.

[0019] FIG. 6D depicts a cascaded reversing-valve system operating in an air-cooling-only mode in accordance with the present disclosure.

[0020] FIG. 6E depicts a cascaded reversing-valve system operating in an air-heating-only mode in accordance with the present disclosure.COE-034-WO (92575-3133)

[0021] FIG.7A depicts a cross-sectional view of cascaded reversing valves in accordance with the present disclosure.

[0022] FIG. 7B depicts an external arrangement of cascaded reversing valves in accordance with the present disclosure.

[0023] FIG. 8A depicts a rooftop system operating in a water-heating-only mode in accordance with the present disclosure.

[0024] FIG. 8B depicts a rooftop system operating in a water-heating and air-heating mode in accordance with the present disclosure.

[0025] FIG. 8C depicts a rooftop system operating in an air-cooling and water-heating mode in accordance with the present disclosure.

[0026] FIG. 8D depicts a rooftop system operating in an air-cooling-only mode in accordance with the present disclosure.

[0027] FIG. 8E depicts a rooftop system operating in an air-heating-only mode in accordance with the present disclosure.

[0028] FIG. 9 depicts a control process for selecting among water-heating-only, airheating-only, water-heating and air-heating, air-cooling-only, and air-cooling and waterheating operating modes based on water-heating demand and thermostat setpoints in accordance with the present disclosure.

[0029] The present disclosure provides a more detailed and specific description with reference to the accompanying drawings. The drawings and specific descriptions of the drawings, as well as any specific or other embodiments discussed, are intended to be read in conjunction with the entirety of this disclosure.DETAILED DESCRIPTION

[0030] Conventional heat pump water heater systems typically include two primary components: (1) a water tank and (2) a heat pump (i.e., a heat exchanger and associated refrigeration components) for generating heat to warm water in the tank. Because the water tank and the heat pump are separate components, each requires its own dedicated installation space. In contrast, passive electric water heaters incorporate the electric heating element within the water tank itself. As a result, electric water heaters are often preferred in applications with limited available space, such as condominiums or apartment homes. These space limitations can hinder replacement of an electric resistance w aterCOE-034-WO (92575-3133)heater with a heat-pump-based system, particularly where little or no additional room exists to accommodate the heat-pump assembly. In many multi-unit buildings, further constraints may arise from building codes, aesthetic requirements, orproperty-management rules that restrict placement of exterior equipment, such as outdoor heat exchangers, thereby limiting options for upgrading or modifying water-heating infrastructure.

[0031] This disclosure relates generally to systems for selectively heating water or conditioning a space (e.g., heating, cooling, humidifying, dehumidifying, or combinations thereof). In some instances, the systems include an outdoor heat exchanger, a water heater, an air handler, and a valve assembly with one or more valves for selectively delivering refrigerant to the air handler and / or the water heater. For example, the systems may be implemented using an existing air conditioning or heat pump system that includes an outdoor heat exchanger and an air handler with an indoor heat exchanger, supplemented with a valve assembly having at least one valve configured to redirect refrigerant from the outdoor heat exchanger to a water-heating circuit instead of, or in addition to, the indoor heat exchanger.

[0032] In some embodiments, the systems further include a brazed-plate heat exchanger (BPHX) configured to facilitate thermal energy exchange between different circuits within the system. Because outdoor heat exchangers used in space-conditioning applications often have significantly higher capacity than heat exchangers conventionally used for water-heating applications, directly redirecting refrigerant to a water-heating component can create a capacity mismatch. The BPHX may be used to manage this mismatch by coupling the outdoor heat exchanger to a dedicated water-heating loop in a manner that promotes stable operation and desirable approach temperatures. In certain implementations, an accumulator may also be provided to accommodate differences in capacity, refrigerant charge, or operating conditions between the space-conditioning circuit and the water-heating circuit.

[0033] In some embodiments, the systems include an outdoor unit with an outdoor heat exchanger for exchanging heat between a first refrigerant and an outdoor ambient environment, a water heater, an air handler, and a valve assembly with one or more valves for selectively delivering refrigerant to an air-handling heat exchanger and / or to a waterheating heat exchanger. In certain implementations, the system is configured as anCOE-034-WO (92575-3133)integrated heat pump system in which a single compressor, a single reversing valve, and the valve assembly cooperate to provide multiple operating modes, including waterheating-only, air-heating-only, water-heating-and-air-heating, air-cooling-only, and air-cooling-and-water-heating modes. In other implementations, the system may be realized as a refrigerant management module configured for installation between an existing outdoor unit, an existing air handler, and an existing water heater, or as a rooftop package system in which a water-heating heat exchanger may be disposed within or associated with a rooftop water heater tank

[0034] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments are shown. The concepts disclosed herein may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the concepts to those skilled in the art. Like numbers refer to like, but not necessarily the same or identical, elements throughout.

[0035] Throughout this disclosure, various aspects are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0036] As used herein, the term "about" with reference to dimensions refers to the dimension plus or minus 10% of the recited value.

[0037] In some embodiments, the systems include an outdoor system with an outdoor heat exchanger for exchanging heat between a first refrigerant and an outdoor ambient environment. The outdoor system may be a heat pump system comprising a compressor for circulating refrigerant through a refrigeration circuit including the outdoor heat exchanger. The outdoor system also comprises at least one fan configured to pass air over one or more coils of the outdoor heat exchanger for heating / cooling refrigerant inside theCOE-034-WO (92575-3133)one or more coils. The outdoor system may also comprise other components of the refrigeration circuit, such as a reversing valve when configured as a heat pump system. Other components may be present in the outdoor system such as one or more controllers, an inverter, an expansion device, etc. The outdoor heat exchanger may be, for example, a heat exchanger conventionally used in heating, venting, and air conditioning (HVAC) applications. The outdoor system may be installed and configured for use with the systems described herein, or it may be a preexisting outdoor system that has been modified or retrofitted for use with the systems described herein.

[0038] Although the outdoor heat exchanger is described herein using the phrase “outdoor,” it should be understood that any suitable heat exchanger may be incorporated into the systems described herein, regardless of whether the heat exchanger is positioned “outdoors.” For example, in some embodiments, the outdoor heat exchanger and compressor may be housed together with an air-handling heat exchanger in a rooftop package unit, while the water-heating heat exchanger is disposed within or proximate a water heater tank associated with the rooftop unit.

[0039] The first refrigerant may be any suitable air conditioning refrigerant. For example, the first refrigerant may be an Al class refrigerant, an A2L class refrigerant, an A2 class refrigerant, an A3 class refrigerant, a Bl class refrigerant, a B2L class refrigerant, a B2 class refrigerant, or a B3 class refrigerant, depending on the toxicity and flammability7tolerances of the particular system. In some embodiments, the first refrigerant may be R-22, R-410A, R-454A. R-454B, R-32. R-404A, R-448A, R449-A, R-134a, R-513A, R-450A, R-290. R-152a, R-744, R-717, or the like. Any suitable refrigerant capable of transferring heat in a water heating or space conditioning system may be used.

[0040] In some embodiments, the systems include a valve assembly in fluid communication with the outdoor heat exchanger and including at least one valve. The valve assembly may define a water-heating circuit and an air-handling circuit so that the at least one valve in the valve assembly is configured to receive the first refrigerant from the outdoor unit and selectively deliver the first refrigerant to the water-heating circuit, to the air-handling circuit, or to both circuits concurrently. The at least one valve may therefore have a first configuration in which a fluid circuit is formed with the outdoor heat exchanger and the water-heating circuit, a second configuration in which a fluid circuit isCOE-034-WO (92575-3133)formed with the outdoor unit and the air-handling circuit, and one or more additional configurations in which a fluid circuit is formed that directs refrigerant in parallel or serial flow paths through both the water-heating circuit and the air-handling circuit to provide concurrent water heating and space conditioning.

[0041] In various implementations, the at least one valve may be a three-way valve positioned between the outdoor unit, the water-heating circuit, and the air-handling circuit. In another implementation, the at least one valve may include two or more shut-off valves, such as solenoid valves, arranged to define parallel refrigerant flow paths for selectively supplying refrigerant to the water-heating circuit, the air-handling circuit, or both. The shut-off valves may be controlled such that, in a water-heating-only operating mode, valves associated with the air-handling circuit are closed; in an air-conditioning-only operating mode, valves associated with the water-heating circuit are closed; and in one or more heat-recovery operating modes, both sets of valves are opened to provide concurrent water heating and space conditioning.

[0042] In some embodiments, the systems include a water heater and a brazed-plate heat exchanger (BPHX). The water heater may include a tank. Brazed-plate heat exchangers (BPHXs) are characterized by having two fluid flow paths, each with a fluid inlet and a fluid outlet. The two fluid flow paths are separated from one another by one or more metal plates that conduct heat from the warmer fluid to the cooler fluid. BPHXs are further characterized by the omission of any gaskets or couplings; instead, each plate is brazed together, i.e., joined by heating the attachment points and filling in gaps with a filler metal. In this way, upwards of 95% of the material used in a BPHX contributes to overall heat transfer. In some embodiments, such a BPHX may be located within a refrigerant management module, while in other embodiments, the BPHX or another water-heating heat exchanger may be disposed within or immediately adjacent to the water heater tank, including in rooftop applications.

[0043] In some embodiments, the BPHX may have a first fluid flow path operably coupled to the water-heating circuit in the valve assembly and a second fluid flow path operably coupled to the water tank. In this embodiment, the first fluid flow path and the second fluid flow path in the BPHX may be configured so that the first refrigerant in the first fluid flow path exchanges heat with a fluid in the second fluid flow path via one or more plates in the BPHX. In some embodiments, the BPHX may instead be positionedCOE-034-WO (92575-3133)upstream or downstream of the outdoor heat exchanger, or integrated into a rooftop package unit, while still providing thermal coupling between the refrigerant circuit and water associated with the water heater.

[0044] As used herein, a "‘space” may refer to a room or it may refer to any discrete volume of air, and an '‘air handler” may refer to an air conditioning system or component of an air conditioning system configured to condition the air in a room or a discrete volume of air. For example, an air conditioning system or a component of an air conditioning system configured to deliver conditioned air directly to a room, or to deliver conditioned air via ductwork to one or more rooms in a home, condominium, or apartment home may be considered an “air handler,” and either the room, rooms, home, condominium, or apartment home may be considered a “space.” Furthermore, an outdoor heater configured to provide warmth to an area or to otherwise condition the area may be considered a “air handler” and the air or area immediately surrounding the “air handler” may be considered the “space.”

[0045] In some embodiments, the fluid that passes through the second fluid flow path of the BPHX is water draw n directly from the w ater tank. A pump may circulate the w ater betw een the water tank and the BPHX. In some embodiments, the BPHX and the pump may be installed as part of a single unit, sometimes referred to as a “hydrobox.” The BPHX may therefore enable the exchange of heat from the first refrigerant to the water. The water may then be returned directly to the water tank for subsequent use by a user or the household. For example, the heated water may be delivered by the BPHX to the top of the water tank while cooler water is drawn from the bottom of the water tank for circulating through the BPHX.

[0046] In some embodiments, such as when an existing water heater is retrofitted for use with the systems described herein, the water heater may not be equipped with a recirculation flow path. In other words, the existing water heater may have a water inlet for receiving, for example, municipal water and a water outlet for delivering heated water to the consumer. In these embodiments, the systems described herein may utilize one or more valves and / or T-junctions for the recirculation of water through the BPHX. For example, a T-junction may be installed at the water heater cold water inlet so that the water heater may receive (i) water from a municipal source, or (ii) w ater from the BPHX, depending on the configuration of the valves of the valve assembly, which configurationCOE-034-WO (92575-3133)may be dictated by the needs of the system at a given point in time. Similarly, another T-j unction may be installed at the water heater hot water outlet so that the water heater may deliver water (i) to the consumer, or (ii) to the BPHX, depending on the configuration of the valves of the valve assembly, which configuration may be dictated by the needs of the system at a given point in time. In some embodiments, the recirculation circuit may be reversed so that water is drawn from the water heater via a T-junction installed at the cold w ater inlet of the w ater heater, and water is delivered to the water heater via a T-junction installed at the hot water outlet of the water heater.

[0047] In some embodiments, the fluid that passes through the second fluid flow path of the BPHX is a second refrigerant that is configured to circulate through a water heating coil disposed inside or around the w ater tank. The BPHX may therefore enable heat transfer from the first refrigerant to the second refrigerant, and the second refrigerant may then pass through the water heating coil which heats water inside the water tank.

[0048] In some embodiments, the second refrigerant is the same as the first refrigerant. In some embodiments, the second refrigerant is w ater. In other embodiments, the second refrigerant is a different refrigerant than the first refrigerant. In some embodiments, the second refrigerant may be any suitable air conditioning refrigerant. For example, the second refrigerant may be an Al class refrigerant, an A2L class refrigerant, an A2 class refrigerant, an A3 class refrigerant, a Bl class refrigerant, a B2L class refrigerant, a B2 class refrigerant, or a B3 class refrigerant, depending on the toxicity and flammability tolerances of the particular system. In some embodiments, the second refrigerant may be R-22, R-410A, R-454A, R-454B. R-32, R-404A. R-448A. R449-A, R-134a. R-513A. R-450A, R-290, R-152a, R-744, R-717, or the like.

[0049] As described above, the BPHX may be operably connected to the water heating circuit and to the water heater. By connecting the first fluid flow- path in the BPHX to the water heating circuit in the valve assembly, the first refrigerant from the outdoor heat exchanger can pass through the first fluid flow path of the BPHX when the at least one valve in the valve assembly is configured to deliver first refrigerant from the outdoor heat exchanger to the water heating circuit. By connecting the second fluid flow path in the BPHX to the water heater, water from the water heater can pass through the second fluid flow path of the BPHX and exchange heat with the first refrigerant via the one or moreCOE-034-WO (92575-3133)plates in the BPHX. The newly heated water may then recirculate through the water heater.

[0050] The BPHX may instead be operably connected to the outdoor heat exchanger and to the valve assembly. By connecting the first fluid flow path in the BPHX to the outdoor heat exchanger and connecting the second fluid flow path in the BPHX to the valve assembly, first refrigerant can pass through the first fluid flow path and exchange heat with w ater in the second fluid flow path. The newly heated water may then pass through the valve assembly and be delivered either to the water heater or the air handler, depending on the configuration of the one or more valves. When delivered to the water heater, the heated water may subsequently be delivered to a user or user’s appliance (e g., show er, dishw ashing machine, laundry7washing machine, etc.). When delivered to the air handler, the heated water may be used for space conditioning using, for example, a hydronic heat exchanger or a radiative heating element.

[0051] In some embodiments, the BPHX and pump are disposed proximal to or attached to the w ater tank in the w ater heater. For example, a hydrobox including the BHPX and the pump may be secured to a side of the water tank, or at another suitable location proximal to the water tank. Although the BPHX and pump are sometimes described herein as a component of the water heater, the omission of further description of the BPHX and pump as components of the hydrobox or positioned in another location is in the interest of brevity7only. In some embodiments the BPHX may be disposed inside the water heater tank.

[0052] In some embodiments, the systems include an air handler including a fan and a coil. The coil in the air handler may be operably coupled to the air-handling circuit in the valve assembly so that first refrigerant from the outdoor unit may pass through the coil and heat or cool air that is passed over the coil by the fan. The fan may be a conventional rotary fan, a draft inducer motor, or another similar apparatus for driving air. In integrated or rooftop embodiments, the air handler may be included within the same cabinet as the outdoor heat exchanger and compressor, while in split-system or retrofit embodiments, the air handler may be located indoors and fluidly connected to an outdoor unit and a refrigerant management module.

[0053] In some embodiments, the air handler and the outdoor heat exchanger comprise a preexisting HVAC system. For example, in some embodiments, the air handler includesCOE-034-WO (92575-3133)components such as an evaporator coil, compressors, fans, and the like, and may have an air conditioning capacity of from about 1 ton to about 3 tons. In some embodiments, the air handler may further include conventional elements such as a heater kit that includes electric resistive heating element(s) for backup heating. In other embodiments, the air handler may be a component of an existing furnace heating system that includes a burner, a flue, a burner heat exchanger, and a blower so that the systems described herein involve the addition of a coil-based heat exchanger to the furnace heating system. The outdoor heat exchanger may also be a variable speed heat exchanger. Any suitable air handler configured to receive refrigerant from an outdoor unit and / or from a rooftop package unit may be incorporated, modified, or retrofitted into the systems described herein.

[0054] As described above, a heat pump water heater requires more space than a passive electric water heater having the same water capacity because the water tank and the heat pump must be separate, whereas passive electric water heaters can incorporate the electric heating element within the tank. By incorporating a valve assembly and at least one valve as described herein, the outdoor heat exchanger used for HVAC applications, i.e. for space conditioning, may be used to heat water in a water tank, effectively heating the water via a "‘heat pump." By incorporating a BPHX as described herein, the capacity mismatch between the outdoor heat exchangers most commonly used in HVAC applications and water tanks of between about 25 to about 40 gallons may be bridged, enabling the heating of water in these water tanks without creating undesirable conditions.

[0055] The ability to repurpose an outdoor system of an HVAC system to heat a tank of water, effectively heating the water in the same manner as a heat pump would, also enables the conversion of an existing electrical water heater into a heat pump water heater through the addition of a valve assembly, a BPHX, a pump, and one or more T-junctions as described herein. In some cases, water from the w ater tank may be circulated through the BPHX for direct heating. In some cases, a water heating coil may be wrapped around the outside of the water tank, enabling heat transfer from a refrigerant in the w ater heating coil to the w ater in the water tank. The electrical heating element of the existing electrical water heater may therefore be simply ignored, or the w ater heater may be configured for dual -heating with both the “‘heat pump,” i.e. the outdoor heat exchanger, and the preexisting electrical heating element.COE-034-WO (92575-3133)

[0056] In some embodiments, the at least one valve in the valve assembly is a three-way valve. In other words, the at least one valve may have an input configured to receive first refrigerant from the outdoor heat exchanger, a first output configured to deliver the received first refrigerant to the water heating circuit, and a second output configured to deliver the received first refrigerant to the air handler circuit and to the air handler. In some embodiments, the valve assembly includes a first three-way valve for selectively delivering heated first refrigerant to the water heating circuit or the air handler circuit, and a second three-way valve for selectively receiving first refrigerant from the water heating circuit or the air handler circuit and for delivering the received first refrigerant to the outdoor heat exchanger. In some embodiments, one or more check valves and a T-junction may be used in place of the second three-way valve so that the valve assembly may receive the cooled first refrigerant from either the water heating circuit or the air handler circuit without the need to actuate a valve. As used herein, “check valves’" are passive, unidirectional mechanical devices that allow fluid flow in one direction and block reverse flow, and are not actively opened or closed by the controller.

[0057] In some embodiments, the systems include a controller for controlling the systems’ operations. The controller may be configured to actuate the at least one valve to deliver the first refrigerant to the water heating circuit in response to a demand for heated water. The controller may be configured to actuate the at least one valve to deliver the first refrigerant to the air handler circuit in response to a demand for space conditioning. For example, the demand for heated water may take the form of a user actuating a hot water tap. which may further include sending a signal to the controller to actuate the at least one valve to deliver the first refrigerant to the water heating circuit. In other examples, one or more thermostats in the water heater tank may trigger a demand for heated water upon falling below a threshold temperature. In other examples, a demand for heated water may be triggered based on a predetermined schedule so that hot water is present in anticipation of a regular demand, such as in the morning or evening. Each of a hot water tap, one or more thermostats, a scheduled demand, or another stimulus may be present in a single system so that the controller may actuate the at least one valve in a number of circumstances.

[0058] In some embodiments, the at least one valve is configured to deliver first refrigerant to the air handler circuit when in a standby or default state so that the controllerCOE-034-WO (92575-3133)is configured to actuate the at least one valve to deliver first refrigerant to the air handler circuit when there is no demand for heated water or, in some cases, when there is no demand for heated refrigerant at all. In other words, the system may operate in a standby mode in a configuration otherwise identical to a conventional HVAC system and converts into a water heating system only in response to a demand for hot water.

[0059] In some embodiments, the controller is configured to actuate the at least one valve to deliver the first refrigerant to the water heating circuit based on a predetermined schedule. For example, the controller may be configured to heat water in the water heater tank so that hot water is readily available by a specific time of day. In some cases, this scheduled water heating may coincide with periods in which space conditioning is not otherwise desired enabling the system to efficiently heat water in the water heater without sacrificing space conditioning.

[0060] In some embodiments, the controller may be equipped with instructions for prioritizing either water heating or space conditioning, and for selecting among multiple operating modes based on the specific demands of the system. For example, the controller may be configured to select among at least a water-heating-only mode, an air-heating-only mode, a water-heating-and-air-heating mode, an air-cooling-only mode, and an air-cooling-and-water-heating mode. In certain implementations, water-heating-only may be treated as a highest-priority mode when a water-heating demand metric (for example, a difference betw een a desired w ater temperature setpoint and an actual or inferred w ater temperature) exceeds a threshold. When the water-heating demand is reduced below7the threshold, the controller may transition to a space-conditioning mode, which may include either heating or cooling, or to a concurrent heat-recovery mode in which space cooling is provided while recovered heat is used to heat water.

[0061] In one example, w ater heating may be prioritized based on a comparison between a desired storage setpoint (DSSP) and a measured or inferred water temperature (DISP). When (DSSP - DISP) exceeds a water-heating threshold value, the controller may select a w ater-h eating-only mode as a highest-priority mode. When the water-heating demand is satisfied (for example, when (DSSP - DISP) falls below7a threshold or a deadband), the controller may examine one or more user-enabled thermostat setpoints for the conditioned space. If a space-heating demand exists, the controller may select an airheating-only mode; if a space-cooling demand exists, the controller may select either anCOE-034-WO (92575-3133)air-cooling-and-water-heating mode (when residual water-heating demand exists) or an air-cooling-only mode (when no water-heating demand exists), with air-cooling-and-water-heating being prioritized over air-cooling-only while water-heating demand persists.

[0062] In an example heating scenario, when the air handler or other component (e.g., a thermostat) initiates operation in a heating mode, the system may be configured so that the heat exchanger in the air handler operates as a condenser. While the system is operating in the heating mode, a water-heating demand may be initiated by the water heater (e.g., based on one or more thermostats in the water heater). Accordingly, the controller may either (i) maintain configuration of the outdoor unit in the heating mode and reconfigure the valve assembly to direct refrigerant to both the water-heating circuit and the air-handling circuit (a water-heating-and-air-heating mode), or (ii) reconfigure the valve assembly to direct refrigerant exclusively to the water-heating circuit (a water-heating-only mode), depending on the priority scheme. When the water-heating demand is satisfied, the controller may transition to an air-heating-only mode, if a space-heating demand remains, or to an idle or standby mode.

[0063] In a cooling scenario, when the air handler or other component initiates operation in a cooling mode, the system may be configured so that the air-handling heat exchanger operates as an evaporator while the outdoor heat exchanger operates as a condenser. While the system is operating in the cooling mode, a water-heating demand may be initiated by the water heater. In some embodiments, the controller reconfigures the valve assembly so that at least a portion of the refrigerant flow is directed through the water-heating heat exchanger while space cooling is maintained, thereby establishing an air-cooling-and-water-heating or heat-recovery operating mode. When the water-heating demand is satisfied, the controller may automatically reconfigure the valve assembly so that refrigerant flows exclusively between the outdoor heat exchanger and the air-handling heat exchanger, thereby establishing an air-cooling-only operating mode.

[0064] In some embodiments, the system includes a charge compensator configured to increase the amount of first refrigerant in circulation for certain operating modes and to decrease the amount of first refrigerant in circulation for other operating modes. A charge compensator acts as a reservoir for excess refrigerant. Thus, when the system is configured for water-heating-only or for a heat-recovery operating mode, a larger or smaller active refrigerant volume may be selected to mitigate undesirable refrigerant conditions, such asCOE-034-WO (92575-3133)excessive subcooling or overheating, while maintaining stable operation during transitions between water heating, space heating, and space cooling. The charge compensator may be positioned anywhere in the refrigeration circuit, such as at the inlet of the compressor, at the outlet of the compressor, between the indoor and outdoor heat exchangers, or at another suitable location.

[0065] In some embodiments, the water heater in the system is an electric water heater. In an example, the water heating coil may be wrapped around an external surface of the tank so that the water heater becomes a heat pump water heater, even if the water heater was originally configured as an electric water heater. In another example, the water from the water tank may be drawn directly from the w ater tank and circulated through the BPHX before returning, heated, to the water tank. This enables retrofitting existing water heating systems into heat pump water heaters regardless of the style of water heater originally installed. In some embodiments, the electric heating element in the electric water heater may be simultaneously engageable alongside the water heating circuit, enabling a dual-heating water heater.

[0066] In some embodiments, as described herein, the water heater is a lowboy water heater, such as those that are installed in apartment homes or condominiums. As used herein, a “lowboy water heater’7refers to a short and wide electric water heater having a capacity of from about 15 to about 40 gallons that is commonly placed in a closet for small apartments and multi-family settings.

[0067] In some embodiments, the space conditioner or the indoor component of a space conditioner is disposed on top of the water heater, or on top of the lowboy water heater, such as a space conditioner and water heater that are disposed in a utility closet.

[0068] In some embodiments, the valve assembly, pump, and BPHX may be installed next to the lowboy water heater and / or the air handler.

[0069] Methods for selectively heating water or conditioning a space are also disclosed herein. In some embodiments, the methods include providing a system as described herein, such as a system including an outdoor heat exchanger, a valve assembly, a water heater, an air handler, and a controller. In other embodiments, the methods include providing a refrigerant management module configured for installation between an existing outdoor unit and an existing water heater and air handler, or providing a rooftop package system configured to deliver refrigerant and / or heated w ater to one or more indoor spaces.COE-034-WO (92575-3133)

[0070] In some embodiments, the methods include determining, using a controller operatively connected to the at least one valve, that a demand for water heating and / or a demand for space conditioning exists. In response to determining that a demand for water heating exists, the method may include actuating the at least one valve to deliver the first refrigerant to the water-heating circuit, either exclusively (in a water-heating-only mode) or concurrently with del i very of refrigerant to the air-handling circuit (in a water-heating-and-air-heating or air-cooling-and-water-heating mode). In response to determining that only a demand for space conditioning exists, the method may include actuating the at least one valve to deliver the first refrigerant to the air-handling circuit.

[0071] In some embodiments, the methods include scheduling the demand for water heating. The controller may be configured to actuate the at least one valve to deliver first refrigerant to the water-heating circuit based on the scheduling, and to transition between water-heating-only, air-heating-only, water-heating-and-air-heating. air-cooling-only, and air-cooling-and-water-heating modes according to a priority scheme that considers both water-heating demand and user-defined thermostat setpoints.

[0072] In some embodiments, the methods include determining, using a controller operatively connected to the at least one valve, that a demand for water heating or a demand for space conditioning exists. In response to determining that the demand for water heating exists, the method may include actuating the at least one valve to deliver the first refrigerant from the outdoor heat exchanger to the water heating circuit. In response to determining that the demand for space conditioning exists, the method may include actuating the at least one valve to deliver the first refrigerant from the outdoor heat exchanger to the air handler circuit.

[0073] In some embodiments, the methods include scheduling the demand for water heating. The controller may be configured to actuate the at least one valve to deliver first refrigerant to the water heating circuit based on the scheduling.

[0074] Methods for retrofitting an electric water heater to a heat pump water heater are also disclosed herein. In some embodiments, the methods include installing a valve assembly that contains at least one valve, a water heating circuit, and an air handler circuit. The at least one valve may operate as described herein. The at least one valve may be configured to receive a first refrigerant from an outdoor heat exchanger and selectively deliver the first refrigerant to the water heating circuit or to the air handler circuit. TheCOE-034-WO (92575-3133)valve assembly may be installed proximal to the existing electric water heater, for example.

[0075] In some embodiments, the methods include installing a first T-junction at an inlet to the water heater tank and a second T-junction at an outlet to the water heater tank to enable recirculation of water from the water heater tank and through the water heating circuit. By installing one or more T-junctions, a water heater that previously lacked a recirculation circuit may be retrofitted for recirculation. In other embodiments, a water heating coil having a second refrigerant in or around a tank in the electric water heater. By installing a water heating coil, the existing electric water heater may serve essentially as merely a water tank.

[0076] In some embodiments, the methods include installing a brazed-plate heat exchanger (BPHX) having a first fluid flow path, a second fluid flow path, and one or more plates configured to exchange heat between a first fluid in the first flow path and a second fluid in the second flow path.

[0077] In some embodiments, the methods include coupling the water heating circuit to the first fluid flow path in the BPHX so that the first refrigerant flows through the first fluid flow path when the at least one valve is configured for delivering the first refrigerant to the water heating circuit. The methods may include coupling the water heater tank to the second fluid flow path in the BPHX so that the water from the tank flows through the second fluid flow path, thereby enabling heat transfer between the first refrigerant and the water by way of the one or more plates in the BPHX.

[0078] In some embodiments, the methods include coupling the outdoor heat exchanger to the first fluid flow path in the BPHX and the valve assembly to the second fluid flow path in the BPHX so that the first refrigerant flows through the first fluid flow path and exchanges heat with water in the second fluid flow path by way of the one or more plates in the BPHX. The one or more valves in the valve assembly may then be used to selectively deliver the heated water to either the water heating circuit or the air handler circuit.

[0079] Turning now to the Figures, FIG. 1 depicts one embodiment of a system 100 for selectively heating water or conditioning a space. The system 100 includes an outdoor heat exchanger 102 for heating a first refrigerant. A valve assembly 104 is coupled to the outdoor heat exchanger 102 and includes at least one valve, such as first valve 106, aCOE-034-WO (92575-3133)water heating circuit 108, and an air handler circuit 110. The first valve 106, which is depicted as a three-way valve, is configured to receive the first refrigerant from the outdoor heat exchanger 102 and selectively deliver the first refrigerant to the water heating circuit 108 or the air handler circuit 110.

[0080] The system 100 also includes a water heater 112 having a tank 114. A brazed-plate heat exchanger (BPHX) 118 having a first fluid flow path is operably coupled to the water heating circuit 108 and configured to receive the first refrigerant from the first valve 106. The BPHX 118 also has a second fluid flow path operably coupled to the water heater 112 and configured to receive water from the water heater 112.

[0081] The system also includes an air handler 120 having a fan 122 and a coil 124. The coil 124 is operably coupled to the air handler circuit 110 and is configured to receive the first refrigerant from the first valve 106.

[0082] FIG. 1 further depicts a second three-way valve 126 for selectively receiving first refrigerant from the BPHX 118 or from the coil 124 and for delivering the first refrigerant to the outdoor heat exchanger 102. Instead of the second three-way valve 126, the system may include a T-junction and one or more check valves for managing the return flow of first refrigerant from the water heating circuit or the air handler circuit.

[0083] FIG. 1 further depicts a recirculation pump 128 for facilitating water flow through the water heater 112 after heating by the BPHX 118. Although not depicted, one or more check valves may be used to prevent back flow of refrigerant / fluid to the water tank or to the space heater.

[0084] A controller 130 having, in some embodiments, a user interface 132 is communicatively coupled to the valve assembly 104 and to the outdoor unit 1 2. The controller 130 is configured to actuate the one or more controllable valves 106 of the valve assembly 104 to deliver the first refrigerant to the water-heating circuit 108 and / or the airhandling circuit 110 according to one or more operating modes. For example, the controller 130 may selectively configure the system 100 in a water-heating-only mode, an air-heating-only mode, a water-heating-and-air-heating mode, an air-cooling-only mode, or an air-cooling-and-water-heating mode as described further with respect to FIGS. 5A-5E, 6A-6E, and 8A-8E.

[0085] In FIG. 1, the controller 130 is configured to actuate the first valve 106 to deliver the first refrigerant to the water heating circuit 108 in response to a demand for heatedCOE-034-WO (92575-3133)water. The controller 130 is also configured to actuate the first valve 106 to deliver the first refrigerant to the air handler circuit 110 in response to a demand for space conditioning. In embodiments in which a second valve 126 is included, the controller 130 is also configured to actuate the second valve 126 in tandem with the first valve 106 to ensure proper first refrigeration circulation through the particular circuit engaged.

[0086] FIG. 2 depicts one embodiment of a system 200 for selectively heating water or conditioning a space, with like reference numbers referring to like structures as FIG. 1. FIG. 2 depicts an alternative arrangement of elements in which the BPHX 118 has a first fluid flow path operably coupled to the outdoor heat exchanger 102 and a second fluid flow path operably coupled to the valve assembly 104. The BPHX 118 receives first refrigerant from the outdoor heat exchanger 102 in the first fluid flow path and facilitates thermal energy exchange with water in the second fluid flow path. The water is delivered to the valve assembly 104 where it is subsequently delivered to either the water heating circuit 108 or the air handler circuit 110 depending on the configuration of the first valve 106.

[0087] Water from the water heater 112 tank 114 is returned to the valve assembly 104 by way of check valve 202 and T-junction 204. Similarly, water from the coil 124 is returned to the valve assembly 104 by way of check valve 206. Thus, the water may return to the BPHX 118 from either of the water heating circuit or the air handler circuit without the need to actuate a return valve. Instead, the check valves 202 and 206 passively permit forward flow through the T-junction 204 while blocking reverse flow.

[0088] Although FIG. 1 is depicted as including a second three-way valve 126 and FIG.2 is depicted as including check valves 202, 206 and the T-junction 204, the system 100 in FIG. 2 or the system 200 in FIG. 2 may include either a three-way valve or check valves and a T-junction. The decision to depict the systems 100, 200 as shown is in the interest of brevity only.

[0089] FIG. 3 depicts a brazed-plate heat exchanger (BPHX) 300 having a first fluid flow path 302 and a second fluid flow path 304 separated from one another by a plurality of plates 306. The first fluid flow path 302 has a fluid inlet 308 and a fluid outlet 310, while the second fluid flow path 304 has a fluid inlet 312 and a fluid outlet 314. The plurality of plates 306 enable a fluid in the first fluid flow path 302 to exchange heat with a fluid in the second fluid flow path 304.COE-034-WO (92575-3133)

[0090] FIG. 4A illustrates one embodiment of a system 400 for selectively heating water or conditioning a space including a refrigerant management module 440 (sometimes referred to as a “Hydrobox'’) configured for installation between an existing outdoor unit 402. an existing air handler 420, and an existing water heater 412. In the illustrated embodiment, the module 440 includes a water-heating heat exchanger 418 (for example, a brazed-plate heat exchanger), a recirculation pump 428, a valve assembly 404, and one or more sensors 416, each of which may be housed within a common enclosure. The valve assembly 404 may include one or more controllable valves (e.g. SV1, SV2, SV3, SV4, SV5) and / or one or more reversing valve(s) 406 configured to direct refrigerant between the outdoor unit 402, the air handler 420, and the water-heating heat exchanger 412, and may further cooperate with an accumulator 405 located in the refrigeration circuit 460 to manage active refrigerant charge during transitions between operating modes. Refrigerant lines from the outdoor unit 402 and to the air handler 420 may be routed into and out of the module 440 so that the module 440 can selectively divert refrigerant to the waterheating heat exchanger 418 without requiring internal modification of the outdoor unit 402. Water lines to and from the water heater 412 may also be routed into the module 440 so that the pump 428 can circulate water through the water-heating heat exchanger 418 and back to the water heater 412. Any type of suitable valves may be used through out valve assembly 404 such as reversing valves, check valves, 3-way valves, solenoid valves, etc.

[0091] FIG. 4B depicts the arrangement of FIG. 4A with indoor and outdoor components identified. In the illustrated embodiment, the outdoor unit 402 is positioned outdoors, while the water heater 412, air handler 420, and Hydrobox 440 are located indoors, for example in a shared utility closet. Refrigerant lines extend from the outdoor unit 402 to the refrigerant management module 440 and then to the air handler 420, enabling the module 440 to intercept and selectively redirect refrigerant flow toward the water-heating heat exchanger 418. Water piping extends between the water heater 412 and the module 440 so that water can be drawn from and returned to the water heater 412 in a recirculation loop. FIG. 4B thus illustrates one representative retrofit configuration in which the module 440 is installed between preexisting HVAC and water-heater components while preserving the original outdoor unit 402 and air handler 420.COE-034-WO (92575-3133)

[0092] FIGS. 5 A-5E depict an embodiment of a system 500 in which a reversing valve 506 cooperates with a valve assembly 504 to provide multiple operating modes, including water-heating-only, air-heating-only, concurrent water-heating-and-air-heating, air-cooling-only, and air-cooling-and-water-heating modes. In this embodiment, the valve assembly 504 may include a plurality of controllable valves (for example, a reversing valve 506 and five solenoid valves SV1, SV2, SV3, SV4, SV5) arranged to define refrigerant branch paths toward an air-handling heat exchanger / indoor heat exchanger 524 and a water-heating heat exchanger 518, as well as one or more bypass paths for charge management or defrost routing. The valve assembly 504 further includes a plurality of check valves (for example, three check valves CV1, CV2, CV3) that passively enforce one-way flow along selected return paths while permitting the controllable valves (SV1, SV2, SV3, SV4, SV5) to be actuated without causing undesirable reverse flow. Any type of suitable valves may be used through out valve assembly 504 such as reversing valves, check valves, 3-way valves, solenoid valves, etc. An accumulator 505 is positioned near the suction side of the compressor 550 and is configured to receive or release refrigerant so that the total active refrigerant volume in circulation can be adjusted as the system transitions between the different operating modes illustrated in FIGS. 5A-5E. In the embodiments of FIGS. 5A-5E, the water heater 512 includes atank 514, and a recirculation pump 528 may be used to circulate water through the water-heating heat exchanger 518 and back to the tank 514. The water-heating heat exchanger 528 is depicted as a BPHX but may be any type of suitable heat exchanger.

[0093] FIG. 5A illustrates operation of the system 500 in a water-heating-only mode. One or more temperature sensors and pressure sensors may be positioned at selected points in the refrigeration circuit to measure conditions entering or exiting the waterheating heat exchanger, the air-handling heat exchanger, the expansion device, the compressor suction line, or the liquid line. In this configuration, the controller 130 energizes the reversing valve 506 to orient the system in a heating orientation and actuates valves SV3 and SV4 within valve assembly 504 so that refrigerant discharged from the compressor 550 flows through a branch path leading to the water-heating heat exchanger 518. One or more water-heating branch valves in the valve assembly 504 (for example, valve SV3 are configured to supply refrigerant to the water-heating heat exchanger 512) are opened, while one or more air-handling branch valves (for example, a branch valveCOE-034-WO (92575-3133)such as valve SV1, valve SV2, and valve SV5 supplying the air-handling heat exchanger 524) remain closed. As a result, refrigerant flows from the compressor 550, through the reversing valve 506, through the water-heating heat exchanger 518 where heat is transferred to water associated with the water heater 512, and then returns through appropriate check valves, valve SV4 and suction-side piping to the accumulator 505 and back to the compressor 550. The air-handling heat exchanger 524 is effectively isolated in this mode so that no space conditioning occurs while water-heating demand is being satisfied.

[0094] FIG. 5B illustrates an air-heating-only mode in which the system 500 is configured to deliver heat solely to the conditioned space. In this mode, the reversing valve 506 is again oriented so that the air-handling heat exchanger 524 functions as a condenser and the outdoor heat exchanger 502 functions as an evaporator. The controller 130 actuates the valve assembly 504 so that air-handling branch valves such as valve SV2 supplying the air-handling heat exchanger 524 are opened, while branch valves such as valve SV3 supplying the water-heating heat exchanger 518 are closed. Refrigerant discharged from the compressor 550 flows through the reversing valve 506, through the open branch path to the air-handling heat exchanger 524, where it condenses and releases heat to air driven by a fan or blower, and then returns through valves SV4 and SV5 to suction-side piping and the accumulator 505 to the compressor 550. The water-heating heat exchanger 518 is bypassed so that water heating is not performed while the system 500 satisfies a space-heating demand independently. In this operating mode, the recirculation pump 528 remains off because the water-heating heat exchanger 518 is isolated and no water-side circulation is required.

[0095] FIG. 5C illustrates a water-heating-and-air-heating mode in which heat is delivered concurrently to both the water heater 512 and the conditioned space. In this mode, the reversing valve 506 is again placed in a heating orientation, and the controller 130 actuates the valve assembly 504 so that both air-handling and water-heating branch valves are opened (for example, valves SV2, SV3, SV4, and SV5). Refrigerant leaving the compressor 550 is split into parallel flow paths: a first portion flows to the water-heating heat exchanger 518 to heat water, and a second portion flows to the air-handling heat exchanger 524 to heat air supplied to the space. The relative flow rate through each branch may be determined by the sizing of the branch valves and the control strategyCOE-034-WO (92575-3133)implemented by the controller 130, and may be adjusted by selectively energizing or deenergizing individual solenoid valves SV1-SV5 within the valve assembly 504. One or more check valves CV1, CV2, CV3 ensure that the return flow from each branch merges properly into the suction line without backflow or cross-flow, and the accumulator 505 accommodates variations in refrigerant volume as the system moves into and out of this concurrent heating mode. In embodiments employing a variable-speed compressor, the compressor speed may be modulated to meet simultaneous air-heating and water-heating loads while maintaining appropriate suction and discharge conditions, whereas in embodiments employing a fixed-speed compressor the electric resistance heating element of the water heater 512 may be activated to satisfy the water-heating load, in which case controllable valve SV3 may be maintained in a closed state so that the refrigeration cycle is directed entirely toward the air-handling heat exchanger 524.

[0096] FIG. 5D illustrates operation of the system 500 in an air-cooling-only mode. In this configuration, the controller 130 actuates the reversing valve 506 to place the system in a cooling orientation, such that the air-handling heat exchanger 524 operates as an evaporator to absorb heat from indoor air while the outdoor heat exchanger 502 operates as a condenser to reject heat to the ambient environment. The valve assembly 504 is configured so that air-handling branch valves such as valves SV1, SV4, and SV5, are open, providing a flow path through the air-handling heat exchanger 524, while branch valves such as valve SV3 and SV2 supplying the water-heating heat exchanger 518 are closed. Refrigerant flows from the compressor 550 to the outdoor heat exchanger 152, where it rejects heat and condenses, then flows through an expansion device and into the air-handling heat exchanger 524, where it evaporates and cools indoor air. The refrigerant then flows through open valves SV4 and SV5 and returns through the accumulator 505 to the compressor 550. Because the water-heating branch is isolated, no intentional water heating is performed in this mode. During this mode, the recirculation pump 528 is inactive, as the water-heating heat exchanger 518 is not engaged.

[0097] FIG. 5E depicts an air-cooling-and-water-heating mode (a heat-recovery mode) in which the system 500 provides space cooling while simultaneously transferring the recovered heat to the water heater 512. In this configuration, the reversing valve 506 remains in the same position used in FIGS. 5A-5C, but the outdoor heat exchanger 502 is effectively isolated from the active refrigeration circuit. Refrigerant discharged from theCOE-034-WO (92575-3133)compressor 550 flows through valve SV3 into the water-heating heat exchanger 518, which functions as the condenser by rejecting heat into the water contained in the tank 514. Liquid refrigerant exiting the water-heating heat exchanger 518 then passes through valves such as SV5 and an expansion device before entering the air-handling heat exchanger 524. Within the air-handling heat exchanger 524, the refrigerant evaporates and absorbs heat from the indoor air, thereby cooling the supply air delivered to the conditioned space. The resulting vapor refrigerant returns to the compressor 550 through valve SV1. The controller 130 may modulate solenoid valves SV1-SV5 to balance the cooling load and water-heating load, while the check valves CV1-CV3 and accumulator 505 maintain appropriate refrigerant charge distribution and stable suction-side conditions during transitions into and out of the heat-recovery' operating mode.

[0098] In some embodiments, for example, the embodiments of FIGS. 5A through 5E, the system 500 includes an accumulator 505 and a coordinated valve-actuation sequence that together maintain an appropriate active refrigerant charge across the different operating modes. Because each mode uses a different portion of the refrigerant circuit, the system benefits from deliberate charge handling to avoid excessive subcooling, liquid carryover into the compressor 550, or inadequate refrigerant flow in either the air-handling or water-heating branches. The accumulator 505 and the controllable valves (506 and SV1-SV5), in cooperation with the check valves CV1-CV3, maintain stable operation during transitions.

[0099] During transitions from one mode to another, for example from water heating to air cooling, the controller 130 may temporarily open one or more controllable valves in the valve assembly 504 to increase the effective internal volume of the circuit. This temporary increase in volume provides additional space for migrating refrigerant and allows the accumulator 505 to stabilize the suction side refrigerant density'. When the pressures settle to acceptable values, the controller 130 closes the temporarily opened valves and maintains only the valves required for the selected operating mode.

[0100] In some embodiments, the expansion control between the outdoor heat exchanger and the indoor and water-heating branches may be provided by either a thermostatic expansion valve (TXV) or an electronic expansion valve (EEV). A TXV may be employed to maintain a stable superheat level at the outlet of the evaporator in cooling-oriented modes, relying on thermal sensing at the bulb location to modulate refrigerant flow as theCOE-034-WO (92575-3133)load changes. An EEV may be used in place of, or in addition to, a TXV to provide finer metering control, for example by adjusting valve opening based on sensed pressures and temperatures throughout the system. In any of the embodiments of FIGS. 5A-5E, one or more temperature sensors and pressure sensors may be positioned at selected points in the refrigeration circuit to measure conditions entering or exiting the water-heating heat exchanger, the air-handling heat exchanger, the expansion device, the compressor suction line, or the liquid line. These sensed values may be used by the controller to confirm the operating mode, to regulate refrigerant supply, and to coordinate transitions between heating and cooling configurations. In systems incorporating an EEV, the controller may further adjust refrigerant mass flow through the active branches during mode transitions to stabilize suction pressure, to manage refrigerant charge, and to prevent liquid slugging or excessive superheat.

[0101] FIGS. 6A-6E illustrate an alternative embodiment of a system 600 in which a pair of reversing valves a first reversing valve 632 and a second reversing valve 634 are arranged in a cascaded configuration to establish the requisite heating and cooling flow orientations. In this embodiment, the valve assembly 604 may be simplified relative to the valve assembly 104, 404, 504, and 804 because the cascaded reversing valves 632, 634 are configured to handle a greater portion of the refrigerant routing between an outdoor heat exchanger 602, an air-handling heat exchanger 624, and a water-heating heat exchanger 612. As in the previous embodiment, one or more check valves and an accumulator may be provided to manage refrigerant charge and enforce one-way flow in selected lines. The cascaded arrangement illustrated in FIGS. 6A-6E may be particularly advantageous in systems designed for higher capacities or for installations in which control over multiple condenser and evaporator configurations is desired with minimal additional valves.

[0102] FIG. 6A depicts the system 600 operating in a water-heating-only mode. In this configuration, the controller (not depicted) commands the first and second reversing valves 632, 634 into positions such that refrigerant discharged from the compressor 650 flows through the water-heating heat exchanger 618 and bypasses the air-handling heat exchanger 624. For example, the first reversing valve 622 may route discharge refrigerant toward a junction 613 that feeds the water-heating heat exchanger 618, while the second reversing valve 624 is oriented to direct the return flow from the water-heating heat exchanger 618 back toward the suction side of the compressor 650. Any branch pathsCOE-034-WO (92575-3133)leading to the air-handling heat exchanger 624 are effectively closed or isolated. In this way, the entire available heating capacity of the system is devoted to heating water in the water heater 612.

[0103] FIG. 6B illustrates the system 600 operating in a space-heating-only mode in which the outdoor heat exchanger 602 functions as an evaporator and the air-handling heat exchanger 624 functions as a condenser. In this configuration, the controller positions the first reversing valve 632 and the second reversing valve 634 so that refrigerant is routed through the cascaded connection between the two reversing valves. The refrigerant discharged from the compressor flows through the cascaded reversing-valve arrangement and is delivered to the air-handling heat exchanger 624 to provide heating to the conditioned space, while the refrigerant returning from the air-handling heat exchanger 624 is directed to the outdoor heat exchanger 602 and then back to the compressor. The refrigerant line leading to the water-heating heat exchanger 612 is inactive in this mode, and the associated expansion device is maintained in a fully closed position. Controllable valves SV1 and SV2 in the valve assembly 604 are opened to establish the required flow path for space heating, while any valves associated with the water-heating branch remain closed. Because water heating is not provided by the water-heating heat exchanger 612 in this configuration, the heating element within the water heater 612 supplies water heating if needed and the recirculation pump remains off.

[0104] FIG. 6C depicts an air-cooling-and-water-heating mode for the system 600. In this configuration, the controller positions the first reversing valve 632 and the second reversing valve 634 so that the air-handling heat exchanger 624 operates as an evaporator absorbing heat from indoor air. Refrigerant discharged from the compressor is directed through the cascaded reversing-valve arrangement and routed into the air-handling heat exchanger 624, where it evaporates and cools the supply air stream. A portion of the refrigerant flow is simultaneously routed through the water-heating heat exchanger 612 so that heat recovered from the refrigeration cycle is transferred to water in the tank. In this mode the outdoor heat-exchanger refrigerant line is inactive, and the associated expansion device leading to the outdoor coil remains closed. The controller actuates the valve assembly 604 so that valve SV2 is open and valve SV1 is closed to establish the necessary¬ routing. The recirculation pump is turned on so that water is circulated through the waterheating heat exchanger 612 during this concurrent cooling-and-water-heating operation.COE-034-WO (92575-3133)

[0105] FIG. 6D illustrates the system 600 operating in an air-cooling-only mode. In this configuration, the controller positions the first reversing valve 632 and the second reversing valve 634 so that the air-handling heat exchanger 624 functions as an evaporator and the outdoor heat exchanger 602 functions as a condenser. The refrigerant discharged from the compressor flows through the cascaded reversing-valve arrangement to the outdoor heat exchanger 602, where heat is rej ected to the ambient environment, and the condensed refrigerant then passes through an expansion device before entering the airhandling heat exchanger 624 to cool indoor air. The refrigerant line leading to the waterheating heat exchanger 612 is inactive in this mode, and the associated expansion device is maintained in a fully closed position. The recirculation pump is off. The controller actuates the valve assembly 604 such that valve SV1 is open and valve SV2 is open to establish the required cooling flow path, while any branch valves associated with the water-heating circuit remain closed so that no water heating occurs during this mode.

[0106] FIG. 6E illustrates the system 600 operating in an air-heating-only mode. In this configuration, the controller positions the first reversing valve 632 and the second reversing valve 634 so that the air-handling heat exchanger 624 functions as a condenser to heat the building interior, while the outdoor heat exchanger 602 operates as an evaporator. Refrigerant discharged from the compressor is routed through the cascaded reversing-valve arrangement into the air-handling heat exchanger 624, where it condenses and releases heat to the supply air stream. Liquid refrigerant exiting the air-handling heat exchanger 624 flows through an expansion device and is directed to the outdoor heat exchanger 602, where it absorbs heat from the ambient environment before returning to the compressor. In this mode, the refrigerant path leading to the water-heating heat exchanger 612 is inactive. The associated expansion device remains fully closed, and the recirculation pump is off. The controller actuates the valve assembly 604 so that valve SV1 and valve SV2 are open to establish the necessary refrigerant routing for air heating, while any valves associated with the water-heating branch remain closed so that no water heating occurs during this operation. Any type of suitable valves may be used through out valve assembly 604 such as reversing valves, check valves, 3-way valves, solenoid valves, etc.

[0107] FIG. 7A depicts a cross-sectional view of the reversing valves 632 and 634. Each reversing valve includes a valve body 680 defining internal How passages, a main valveCOE-034-WO (92575-3133)element that is moveable between multiple positions corresponding to different flow orientations, and a set of output ports 684 through which refrigerant is directed depending on the valve position. In the first reversing valve 632, one of the output ports, identified as port 631, is brazed shut so that refrigerant cannot flow through that port in any operating mode. The remaining output ports 684 are fluidly coupled to selected suction and discharge lines 690 and 692 so that, when the main valve element 682 shifts under differential pressure between the suction and discharge sides of the system, refrigerant is routed to the appropriate downstream components to establish the desired heating or cooling orientation.

[0108] FIG. 7B depicts an external arrangement of the cascaded reversing valves 632, 634 and associated suction and discharge lines 690, 692. In the illustrated embodiment, the first reversing valve 632 is fluidly coupled in series with the second reversing valve 634 so that an outlet of the first reversing valve 632 provides refrigerant to an inlet of the second reversing valve 634, or vice versa, depending on the selected orientation. Pilot lines 686 extend from the suction and discharge lines 690, 692 to each valve body 680 to provide the pilot pressures used to actuate the main valve elements. Additional manifolds, mounting brackets, and sendee ports may be provided to facilitate assembly, commissioning, and maintenance of the cascaded reversing-valve arrangement.

[0109] FIGS. 8A-8E show a system 800 that can heat water or condition a space. While illustrated as a rooftop unit, system 800 is suitable for commercial, residential, and other applications. In this embodiment, a system 800 includes the compressor 850, the outdoor heat exchanger 802, and the air-handling heat exchanger 824 and its associated fan. A water-heating heat exchanger 818 is thermally coupled to a tank 814 of a water heater 812, for example by being disposed within the tank 814 or mounted adjacent to the tank 814 and fluidly connected to a water loop within the tank. System 800 includes a valve assembly 804 similar to valve assemblies 104, 404, 504, or 604 to direct refrigerant among the air-handling heat exchanger 824, the outdoor heat exchanger 802, and the waterheating heat exchanger 818 in the various operating modes described below.

[0110] FIG. 8A illustrates the rooftop system 800 operating in a water-heating-only mode. In this configuration, when a water heating demand is present, a controller (not depicted) opens Valve 4 while maintaining Valve 3, Valve 7, and Valve 8 in a closed position. Hot gas discharged from the compressor 850 is routed directly to the water-COE-034-WO (92575-3133)heating heat exchanger 818, where heat is transferred to water contained in or circulating through tank 814. The refrigerant then returns through the suction line to the compressor 850. Because Valves 3, 7. and 8 are closed, the air-handling circuit is isolated and no space conditioning occurs during water heating.

[0111] FIG. 8B illustrates the system 800 operating in a water heating and space heating mode. In this configuration, when a water-heating demand is present, Valve 4 remains open and Valve 9 remains closed. When a heating demand is received from a thermostat (not depicted), the controller (not depicted) opens Valve 1 and Valve 6 while closing Valve 2 and Valve 7. Refrigerant discharged from the compressor 850 first passes through the water-heating heat exchanger 818, producing liquid refrigerant at the outlet of the exchanger. The liquid refrigerant then flows through Valve 1 and an expansion device (e.g., TXV or EEV) to the rooftop outdoor coil of outdoor heat exchanger 802, where heat is absorbed from the ambient environment. The refrigerant thereafter flows through Valve 6 back to the compressor 850. In this embodiment, a gas or electric heating element (not depicted) may supply heat to the building interior until the water-heating demand is satisfied, after which the system transitions into the space-heating-only mode illustrated in FIG. 8E.

[0112] FIG. 8C illustrates a heat-recovery mode in which the rooftop system 800 operates in space-cooling and water-heating mode. In this configuration, Valve 4 is maintained open so that refrigerant discharged from the compressor 850 flows through the water-heating heat exchanger 818, while valves 3 and Valve 9 remain closed. Liquid refrigerant exiting the water-heating heat exchanger 818 is directed through Valve 2 and Valve 5, with Valve 1 and Valve 6 being closed. The refrigerant then passes through the an expansion device and into the rooftop indoor coil of the air-handling heat exchanger 824, where it evaporates and cools indoor air. Vapor refrigerant returns to the compressor 850 through Valve 5. Thus, condenser-side heat is recovered for water heating while the system simultaneously satisfies a cooling demand.

[0113] FIG. 8D illustrates the rooftop system 800 operating in an air-cooling-only mode when no water-heating demand exists. In this embodiment, Valve 4, Valve 5, and Valve 6 are closed, and valves 1, 2, 3, 7, and 8 are open. When a cooling call is received from the thermostat, hot gas discharged from the compressor 850 is routed through a reversing valve 810 and Valve 8 into the rooftop outdoor coil of outdoor heat exchanger 802, whereCOE-034-WO (92575-3133)the refrigerant rejects heat to ambient air and condenses. The condensed refrigerant then flows through Valve 1, Valve 2, and an expansion device before entering the rooftop indoor coil of the air-handling heat exchanger 824 to provide cooling. Low-pressure vapor refrigerant returns through Valve 7 to the reversing valve 810 and ultimately to the compressor 850. The water-heating heat exchanger 818 remains isolated throughout this mode.

[0114] FIG. 8E illustrates the rooftop system 800 operating in an air-heating-only mode when water heating is not active. In response to an air heating demand when water heating is not active, Valve 1, Valve 2, Valve 3, Valve 7, and Valve 8 are opened, while Valve 4, Valve 5, and Valve 6 are closed. In this embodiment, hot gas refrigerant discharged from the compressor 850 flows through Valve 3 and is directed through the reversing valve 810 and Valve 7 into the rooftop indoor coil of the air-handling heat exchanger 824, where it condenses and heats the building. Liquid refrigerant exiting the indoor coil then passes through Valve 2, Valve 1, and an expansion device to the outdoor coil of the outdoor heat exchanger 802. The refrigerant then flows through to the reversing valve 810 via Valve 8 and returns to the compressor 850. The water-heating heat exchanger 818 remains isolated during this operation.

[0115] The system configurations described with reference to FIGS. 8A-8E may be implemented with various types of w ater-side heat exchangers, including brazed-plate heat exchangers located outside or inside the water tank, tube-coil heat exchangers surrounding the tank, coaxial heat exchangers, or other suitable designs. Similarly, the system may¬ employ any suitable compressor type (e.g.. scroll, rotary, fixed-speed, variable-speed), any rooftop heat exchanger design (e.g., tube-fin coil, micro-channel coil), and any suitable indoor blower (e.g., backward-curved, forward-curved, direct-drive, or belt-drive). Either TXVs or EEVs may be employed for expansion control without departing from the scope of the present disclosure. Any type of suitable valves may be used through out valve assembly 804 such as reversing valves, check valves, 3-way valves, solenoid valves, etc. Although figures 8A-8E depict a reversing valve 810 and 8 controllable valves any suitable number of valves to achieve such an arrangement may be used.

[0116] FIG. 9 illustrates a control process 900 for selecting among the water-heating-only, air-heating-only, water-heating-and-air-heating, air-cooling-only, and air-cooling-and-water-heating operating modes based on water-heating demand and thermostatCOE-034-WO (92575-3133)setpoints. In the illustrated embodiment, the controller 130 receives inputs corresponding to a water-heating demand setpoint (DSSP), a measured or inferred water temperature or proxy value (DISP), and one or more space-conditioning setpoints from a thermostat or other user interface. The controller 130 evaluates a water-heating demand metric, such as the difference (DSSP - DISP), and compares that metric to a water-heating threshold or deadband. When the water-heating demand metric exceeds the threshold, the controller 130 may select a water-heating-only mode as the highest-priority operating mode to quickly raise the water temperature. When the water-heating demand metric falls below the threshold or into a deadband, the controller 130 may transition from the water-heating-only mode to a space-heating-only, space-cooling-and-water-heating, or space-cooling-only mode, depending on whether a space-heating demand or space-cooling demand exists.

[0117] In some embodiments, the control process 900 further considers user-configurable priorities or scheduling information. For example, the controller 130 may be configured to prioritize water-heating-only operation during certain time windows (such as early morning hours), to prioritize space conditioning during occupied hours, or to prefer heat-recovery modes (air-cooling-and-water-heating) whenever concurrent cooling and water-heating demands exist. During transitions between modes such as switching from water-heating-only to air-heating-only or from air-cooling-only to an air-cooling-and-water-heating mode the controller 130 may temporarily adjust valve positions in valve assemblies 104, 404, 504. 604, 804 and utilize the accumulator to stabilize refrigerant mass distribution, thereby avoiding excessive subcooling, flashing at expansion devices, or compressor overloading. The controller 130 may also coordinate defrost cycles of the outdoor heat exchanger with water-heating operation so that heat extracted from the waterheating loop assists in defrost, or so that defrost events are scheduled during periods of low water-heating and space-conditioning demand.

[0118] In some embodiments, the methods include operably coupling the air handler heating circuit to an air handler, and then selectively delivering first refrigerant from the outdoor heat exchanger to either the water heating circuit or the air handler circuit. By installing a valve assembly. BPHX. and pump as described herein, an existing electric water heater can be retrofitted to operate as a heat pump water heater by taking advantage of an existing heat pump heat exchanger, such as the one typically used for HVACCOE-034-WO (92575-3133)applications, to heat the water in the existing electric water heater without engaging the electric heating element(s). However, as described above, a BPHX may advantageously transfer heat from the refrigerant heated by the outdoor heat exchanger, i.e., the heat pump heat exchanger, to the water in the tank because the heat exchangers typically used for HVAC applications are much larger in capacity than those used in conventional heat pump water heaters. Furthermore, leveraging the larger capacity heat exchanger enables the formation of a water heating system with a much shorter recovery time compared to conventional heat pump water heaters of the same fluid capacity while simultaneously maintaining efficiencies of greater than 1 UEF (Uniform Energy Factor). The systems described herein, when heating water, have efficiencies of around 3 or greater UEF as compared to electric water heaters which have efficiencies of less than 1 UEF.

[0119] Though the disclosed examples include particular arrangements of a number of parts, components, features, and aspects, the disclosure is not limited to only those examples or arrangements shown. Any one or more of the parts, components, features, and aspects of the disclosure may be employed alone or in other arrangements of any two or more of the same.

[0120] Although certain product features, functions, components, and parts have been described herein in accordance with the teachings of the present disclosure, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the disclosure that fairly fall w ithin the scope of permissible equivalents.

[0121] Unless otherwise noted, the terms used herein are to be understood according to conventional usage by those of ordinary skill in the relevant art. In addition to the definitions of terms provided below, it is to be understood that as used in the specification and in the claims, “a’' or “an’" may mean one or more, depending upon the context in which it is used.

[0122] Throughout this application, the term '‘include,’’ ‘'include(s)” or ‘'including” means “including but not limited to.” Note that certain embodiments may be described relating to a single element, but the corresponding description should be read to include embodiments of two or more elements. Different features, variations, and multiple different embodiments are shown and described herein with various details. What has been described in this application at times in terms of specific embodiments is done forCOE-034-WO (92575-3133)illustrative purposes only and without the intent to limit or suggest that what has been conceived is only one particular embodiment or specific embodiments. It is to be understood that this disclosure is not limited to any single specific embodiments or enumerated variations. Many modifications, variations and other embodiments will come to mind of those skilled in the art, and which are intended to be and are in fact covered by this disclosure. It is indeed intended that the scope of this disclosure should be determined by a proper legal interpretation and construction of the disclosure, including equivalents, as understood by those of skill in the art relying upon the complete disclosure present at the time of filing.

[0123] Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations could include, while other implementations do not include, certain features, elements, and / or operations. Thus, such conditional language generally is not intended to imply that features, elements, and / or operations are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and / or operations are included or are to be performed in any particular implementation.

[0124] What has been described herein in the present specification and drawings includes examples of systems, apparatuses, methods, devices, and / or techniques. It is, of course, not possible to describe every conceivable combination of components and / or methods for purposes of describing the various elements of the disclosure, but it may be recognized that many further combinations and permutations of the disclosed elements are possible. Accordingly, it may be apparent that various modifications may be made to the disclosure without departing from the scope thereof. In addition, or as an alternative, other embodiments of the disclosure may be apparent from consideration of the specification and annexed drawings, and practice of the disclosure as presented herein. It is intended that the examples put forth in the specification and annexed drawings be considered, in all respects, as illustrative and not limiting. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

COE-034-WO (92575-3133)CLAIMSWhat is claimed is:

1. A system for selectively heating water and conditioning a space, the system comprising:a compressor configured to compress a refrigerant;an outdoor heat exchanger fluidly coupled to the compressor and configured to exchange heat between the refrigerant and an ambient environment;an air-handling heat exchanger configured to exchange heat between the refrigerant and air supplied to the space;a water-heating heat exchanger configured to exchange heat between the refrigerant and water associated with a water heater tank;a valve assembly fluidly coupled to the compressor and the heat exchangers and comprising at least one controllable valve and / or at least one reversing valve; anda controller operatively coupled to the valve assembly,wherein the controller is configured to control the valve assembly to selectively direct the refrigerant compressed by the compressor to one or more of the air-handling heat exchanger and the water-heating heat exchanger.

2. The system of claim 1, wherein the reversing valve is configured to establish a heating orientation or a cooling orientation of the refrigerant.

3. The system of claim 1, wherein the valve assembly comprises a plurality of solenoid valves configured to direct the refrigerant along parallel refrigerant flow paths.

4. The system of claim 1, wherein the controller is configured to direct the refrigerant to the water-heating heat exchanger during a water-heating-only operating mode.

5. The system of claim 1, wherein the controller is configured to direct the refrigerant to the air-handling heat exchanger during an air-heating-only operating mode.COE-034-WO (92575-3133)6. The system of claim 1 , wherein the controller is configured to direct the refrigerant to the air-handling heat exchanger and the water-heating heat exchanger during a water-heating and air-heating operating mode.

7. The system of claim 1, wherein the controller is configured to direct the refrigerant to the outdoor heat exchanger during an air-cooling-only operating mode.

8. The system of claim 1, wherein the controller is configured to direct the refrigerant to the water-heating heat exchanger and the air-handling heat exchanger during an air-cooling and water-heating operating mode.

9. The system of claim 1, wherein the water-heating heat exchanger comprises a brazed-plate heat exchanger having a refrigerant flow path and a water flow path separated by a plurality7of thermally conductive plates.

10. The system of claim 1, wherein the valve assembly comprises a first reversing valve and a second reversing valve, the first and second reversing valves being configured to operate in a cascaded arrangement to establish a heating orientation or a cooling orientation of the refrigerant.

11. The system of claim 10, wherein each of the first and second reversing valves comprises a pilot-actuated valve body having pilot lines fluidly coupled to a suction line and a discharge line of the refrigerant circuit.

12. The system of claim 1, wherein the water-heating heat exchanger is disposed within a water heater tank.

13. A method of operating a combined space-conditioning and water-heating system, the method comprising:operating a compressor to circulate a refrigerant through an outdoor heat exchanger;COE-034-WO (92575-3133)controlling a valve assembly comprising at least one controllable valve and / or at least one reversing valve to selectively direct the refrigerant to an air-handling heat exchanger, a water-heating heat exchanger, or both; andmanaging refrigerant charge within the system during transitions between operating modes by actuating one or more valves of the valve assembly to adjust a flow path of the refrigerant.

14. The method of claim 13, further comprising determining a priority between a waterheating demand and a space-conditioning demand and directing the refrigerant according to the determined priority.

15. The method of claim 13, wherein selectively directing the refrigerant comprises directing refrigerant exclusively to the air-handling heat exchanger during a spaceconditioning-only operating mode.

16. The method of claim 13, wherein selectively directing the refrigerant comprises directing refrigerant exclusively to the water-heating heat exchanger during a water-heating-only operating mode.

17. The method of claim 13, wherein selectively directing the refrigerant comprises directing refrigerant concurrently to the air-handling heat exchanger and the water-heating heat exchanger during a heat-recovery operating mode.

18. The method of claim 13, wherein managing refrigerant charge comprises temporarily routing refrigerant through an intermediate refrigerant flow path during an operating-mode transition.

19. The method of claim 13, wherein water heating is prioritized over space conditioning when simultaneous demands exist.

20. The method of claim 13, further comprising coordinating a defrost operation with water heating.COE-034-WO (92575-3133)21. A refrigerant management module configured for installation between an existing I IV ACsystem and an existing water heater, the module comprising:a water-heating heat exchanger comprising a refrigerant-side heat exchange path and a water-side heat-exchange path;a valve assembly disposed along the refrigerant-side heat-exchange path and comprising plurality of controllable valves configured to direct refrigerant received from the existing HVAC system along one or more selectable flow paths;a controller operatively coupled to the valve assembly and configured to actuate the controllable valves to selectively deliver the refrigerant to the water-heating heat exchanger or to an air-handling heat exchanger of the existing HVAC system, wherein installation of the refrigerant management module enables the existing water heater to operate as a heat pump water heater without replacing the existing HVAC.

22. The refrigerant management module of claim 21, wherein the water-heating heat exchanger comprises a brazed-plate heat exchanger configured to transfer heat betw een the refrigerant and water circulated from the existing water heater.

23. The refrigerant management module of claim 21, further comprising one or more temperature sensors or pressure sensors operatively coupled to the controller.

24. The refrigerant management module of claim 21 , wherein the module is installable without modification of an outdoor HVAC unit.

25. The refrigerant management module of claim 21. wherein the module is configured to enable concurrent space-conditioning and water-heating.

26. The refrigerant management module of claim 21, w herein the w ater heater is a lowboy electric water heater.COE-034-WO (92575-3133)27. The refrigerant management module of claim 21 , wherein the controller is configured to manage refrigerant charge during transitions between water-heating- only, air-heating-only, water-heating-and-air-heating, air-cooling-only, and air- cooling-and-water-heating modes.

28. The refrigerant management module of claim 21, wherein the module is configured to enable a water-heating-only mode, an air-heating-only mode, a w ater-heating and air-heating mode, an air-cooling-only mode, and an air-cooling and waterheating mode.

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