PACKAGED MULTI-FUNCTIONAL AIR SOURCE HEAT PUMP INTEGRATED WITH A HYDRONIC LOOP FOR COOLING/HEATING ENERGY STORAGE

Abstract

An improved ASHP having an integrated hydronic loop for thermal energy storage is provided. The hydronic loop includes a phase change material storage module to release energy capacity during peak electricity hours. The ASHP further includes an indoor air-to-refrigerant heat exchanger, an outdoor air-to-refrigerant heat exchanger. a refrigerant-to-water heat exchanger, three electronic expansion valves to control refrigerant flow, and a multi-capacity compressor with a suction line accumulator to store excess refrigerant charge. The ASHP includes at least six working modes of operation, including: (1) space cooling mode: (2) cooling energy charge/simultaneous space cooling and cooling energy charge/defrost mode: (3) cooling storage discharge mode: (4) space heating mode: (5) heating energy charge mode: and (6) heating storage discharge mode. This and other embodiments are uniquely suited for residential space cooling, space heating, water heating, and commercial applications with high water heating and space cooling demands.

Claims

1. A multifunctional system comprising: an indoor air-to-refrigerant heat exchanger; an outdoor air-to-refrigerant heat exchanger; a refrigerant-to-water heat exchanger, wherein the indoor air-to-refrigerant heat exchanger, the outdoor air-to-refrigerant heat exchanger, and the refrigerant-to-water heat exchanger are coupled together in parallel; a first electronic expansion valve that is series-connected to the indoor air-to-refrigerant heat exchanger, a second electronic expansion valve that is series-connected to the outdoor air-to-refrigerant heat exchanger, and a third electronic expansion valve that is series-connected to the refrigerant-to-water heat exchanger; a compressor to circulate refrigerant through the indoor air-to-refrigerant heat exchanger, the outdoor air-to-refrigerant heat exchanger, and the refrigerant-to-water heat exchanger; first and second four-way reversing valves coupled together in series; and a hydronic loop, the hydronic loop comprising: the refrigerant-to-water heat exchanger, a storage module configured to store a phase change material therein, wherein the storage module includes a water-carrying channel to allow a thermal exchange between water carried by the water-carrying channel and the phase change material, and a pump configured to circulate water through the storage module and through the refrigerant-to-water heat exchanger; and controller circuitry communicatively coupled with the first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to cause the multifunctional system to provide any one of space cooling, dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, and heating mode outdoor defrost mode, cooling-storage discharge, space heating, heat-energy charge, or heat-storage discharge.

2. The system of claim 1, wherein the controller circuitry is configured to: present a user interface configured to receive a user input selecting any one of the system's functional modes comprising space cooling, dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, heating mode outdoor defrost, cooling-storage discharge, space heating, heat-energy charge, and heat-storage discharge.

3. The system of claim 1, wherein the controller circuitry is configured to: receive a first user input for the multifunctional system to provide space cooling, and configure, in response to the received first user input, first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide space cooling.

4. The system of claim 1, wherein the controller circuitry is configured to: receive a second user input for the multifunctional system to provide dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, or heating mode outdoor defrost, and configure, in response to the received second user input, configure the first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, or heating mode outdoor defrost.

5. The system of claim 1, wherein the controller circuitry is configured to: receive a third user input for the multifunctional system to provide cooling-storage discharge, and configure, in response to the received third user input, first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide cooling-storage discharge.

6. The system of claim 1, wherein the controller circuitry is configured to: receive a fourth user input for the multifunctional system to provide space heating, and configure, in response to the received fourth user input, first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide space heating.

7. The system of claim 3, wherein the controller circuitry is configured to turn off the pump in response to receiving the first user input or the fourth user input.

8. The system of claim 1, wherein the controller circuitry is configured to: receive a fifth user input for the multifunctional system to provide heat-energy charge, and configure, in response to the received fifth user input, first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide heat-energy storage.

9. The system of claim 4, wherein the controller circuitry is configured to turn off the indoor air-to-refrigerant heat exchanger in response to receiving the second user input or the fifth user input.

10. The system of claim 1, wherein the controller circuitry is configured to: receive a sixth user input for the multifunctional system to provide heat-storage discharge, and configure, in response to the received sixth user input, first, second, and third expansion valves, the first and second four-way reversing valves, and the pump to provide heat-storage discharge.

11. The system of claim 5, wherein the controller circuitry is configured to turn off the outdoor air-to-refrigerant in response to receiving the third user input or the sixth user input.

12. The system of claim 1, wherein the water-to-refrigerant heat exchanger includes a brazed plate water heater.

13. The system of claim 1, further comprising a suction line accumulator coupled to an input side of the compressor.

14. An air source heat pump comprising: a compressor configured to compress a refrigerant; an indoor air-to-refrigerant heat exchanger configured to receive the refrigerant from the compressor along an indoor line; an outdoor air-to-refrigerant heat exchanger configured to receive the refrigerant from the compressor along an outdoor line; a refrigerant-to-water heat exchanger configured to receive the refrigerant from either of the indoor line or the outdoor line for transferring heat to a supply of water; a hydronic loop comprising a closed loop through the water-to-refrigerant heat exchanger, the hydronic loop including a storage module containing a phase change material therein, the hydronic loop further including a pump configured to circulate the supply of water through the storage module and through the refrigerant-to-water heat exchanger; a first electronic expansion valve that is series-connected to the indoor air-to-refrigerant heat exchanger, a second electronic expansion valve that is series-connected to the outdoor air-to-refrigerant heat exchanger, and a third electronic expansion valve that is series-connected to the refrigerant-to-water heat exchanger; and a controller module communicatively coupled with a first four-way reversing valve and a second four-way reversing valve for selectively routing the refrigerant from a discharge side of the compressor to the indoor air-to-refrigerant heat exchanger, the outdoor air-to-refrigerant heat exchanger, and the refrigerant-to-water heat exchanger.

15. The heat pump of claim 14, further comprising a suction line accumulator coupled directly with a suction side of the compressor.

16. The heat pump of claim 14, wherein the water-to-refrigerant heat exchanger comprises a brazed plate water heater.

17. The heat pump of claim 14, wherein each of the indoor air-to-refrigerant heat exchanger and the outdoor air-to-refrigerant heat exchanger comprise a coil and a fan.

18. The heat pump of claim 14, wherein the indoor air-to-refrigerant heat exchanger and the first expansion valve are in fluid communication with each other along the indoor line.

19. The heat pump of claim 14, wherein the outdoor air-to-refrigerant heat exchanger and the second expansion valve are in fluid communication with each other along the outdoor line.

20. The heat pump of claim 14, wherein the phase change material comprises water, glycerol, salt hydrates, or paraffin wax.

21. The heat pump of claim 14, wherein the storage module comprises a ceiling panel, a floor panel, or a wall panel containing the phase change material therein.

22. The heat pump of claim 14, wherein the storage module comprises a storage tank containing the phase change material therein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 illustrates a prior art air-source heat pump for transferring heat between indoor air and outdoor air.

[0013] FIG. 2 illustrates an improved air-source heat pump having an integrated hydronic loop having a phase change material in a space cooling mode of operation.

[0014] FIG. 3 illustrates the heat pump of FIG. 2 in dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, and heating mode outdoor defrost modes of operation.

[0015] FIG. 4 illustrates the heat pump of FIG. 2 in cooling storage discharge mode of operation.

[0016] FIG. 5 illustrates the heat pump of FIG. 2 in a space heating mode of operation.

[0017] FIG. 6 illustrates the heat pump of FIG. 2 in a heat energy charge mode of operation.

[0018] FIG. 7 illustrates the heat pump of FIG. 2 in a heating storage discharge mode of operation.

DETAILED DESCRIPTION OF THE CURRENT EMBODIMENT

[0019] The current embodiment is directed to an air-source heat pump (ASHP) having an integrated hydronic loop to charge or discharge a phase change material (PCM) contained within a suitable storage module. As generally set forth below, the ASHP includes two series-connected four-way reversing valves to alter refrigerant flow in various operating modes. The ASHP also includes three electronic expansion valves and a suction line accumulator to control optimum subcooling and superheat degrees and to manage charge allocation across six operating modes.

[0020] More specifically, an ASHP having an integrated hydronic loop in accordance with one embodiment is shown in FIGS. 2-7 and generally designated 30. The ASHP 30 includes an indoor air-to-refrigerant heat exchanger 32, an outdoor air-to-refrigerant heat exchanger 34, a compressor 36, a suction line accumulator 38, a first four-way reversing valve 40, and first and second electronic-expansion valves 41, 43. The ASHP 30 further includes a hydronic loop 42 for storing energy within a phase change material (PCM). The hydronic loop 42 includes a water-to-refrigerant heat exchanger 44, a storage module 46 for the PCM, and a pump 48 for circulating water through the hydronic loop 42. The hydronic loop 42 is configured to circulate water through a closed loop to facilitate the storage of energy, depending on the particular mode of operation, and hydronic loop 42 is coupled to the ASHP 30 via three electronic expansion valves 41, 43, 50 and a second four-way reversing valve 52. Each electronic expansion valve 41, 43, 50 is parallel connected to a respective optional check valve 54, 56, 58. The integrated charge management system also includes control circuity (e.g., a digital thermostat having a graphical user interface) 60 communicatively coupled with the pump 48, the four-way reversing valves 40, 52 and the electronic expansion valves 41, 43, 50 to selectively configure the four-way reversing valves 40, 52 and the electronic expansion valves 41, 43, 50 and to cause the ASHP 30 to be operative across each of six modes of operation.

[0021] The indoor heat exchanger 32 and the first electronic expansion valve 41 are series connected along an indoor line 62, while the outdoor heat exchanger 34 and the second electronic expansion valve 43 are series connected along an outdoor line 64. The indoor line 62 and the outdoor line 64 include an enclosed passageway through which refrigerant flows. The heat exchangers 32, 34 include any construction adapted to transfer heat between a first medium (e.g., refrigerant) and a second medium (e.g., air). The outdoor line 64 includes a filter or a dryer 66 that is series connected between the first electronic expansion valve 41 and the second expansion valve 43, and the heat exchangers 32, 34 each include a fan 68, 69 to direct the flow of air over a coil 70, 71.

[0022] The compressor 36 and the suction line accumulator 38 are series connected along a compressor suction line 72. The output of the compressor 36 flows through to the first four-way reversing valve 40. The hydronic loop 42 includes any suitable air-to-water heat exchanger 44, for example a brazed plate heat exchanger. The output of the air-to-water heat exchanger 44 is coupled along the hydronic loop 42 to the PCM storage module 46.

[0023] Each reversing valve 40, 52 can selectively control the flow of refrigerant between four ports. In some embodiments, the reversing valves 40, 52 are operated by an electromechanical solenoid that is movable between four positions. The first reversing valve 40 includes four ports (described herein in clockwise fashion for convenience): a first port in fluid communication with the compressor 36; a second port in fluid communication with a T-junction 74 between the second reversing valve 52 and the suction line accumulator 38; a third port in fluid communication with the second reversing valve 52; and a fourth port in fluid communication with the indoor refrigerant-to-air heat exchanger 32. The second reversing valve 52 includes four ports: a first port in fluid communication with the third port of the first reversing valve 40; a second port in fluid communication with the aforementioned T-junction 74; a third port in fluid communication with the outdoor heat exchanger 34; and a fourth port in fluid communication with the refrigerant-to-water heat exchanger 44.

[0024] The ASHP 30 and the integrated hydronic loop 42 comprise a multi-functional unit, capable of meeting home comfort requests, including space cooling, space heating, domestic water heating, and energy storage. The configuration shown in FIG. 2 can actively adjust charge allocation and thus optimize operational efficiencies across six modes of operation: (1) space cooling mode; (2) cooling energy charge/defrost mode; (3) cooling storage discharge mode; (4) space heating mode; (5) heat energy charge mode; and (6) heating storage discharge mode. The reversing valves 40, 52 switch among the operation modes and control refrigerant flow directions, while the electronic expansion valves 41, 43, 50 allocate refrigerant mass in active components, while excess charge is stored in the suction line accumulator 38.

[0025] Operation of the heat pump across the six modes of operation will now be described. As shown in the drawings, bold flow lines depict cold refrigerant, thin flow lines depict warm refrigerant, and broken flow lines depict the absence of flow. In a dedicated space cooling mode, shown in FIG. 2, the indoor heat exchanger coil 70 operates as an evaporator coil and the outdoor heat exchanger coil 71 operates as a condenser coil. The refrigerant flow to the refrigerant-to-water heat exchanger 44 is shut-off by its upstream third electronic expansion valve 50. The first expansion valve 41 (upstream of the indoor heating coil 70) controls a 5.6K superheat degree at the evaporator exit. The second electronic expansion valve 43 is fully open or is bypassed by the second check valve 56 (each of the check valves are one-way check valves). Both of the indoor blower fan 68 and the outdoor blower fan 69 drive target air flow rates, respectively. As a result, the indoor heat exchanger 32 absorbs heat from the indoor air as it passes over the evaporator coil 70, and the outdoor heat exchanger 34 releases the absorbed heat to the outside air. The liquid refrigerant returns to the evaporator coil 70.

[0026] In a cooling energy charge mode (FIG. 3), water circulates from the PCM storage module 46 to the refrigerant-to-water heat exchanger 44. This heat exchanger 44 operates as an evaporator with its upstream expansion valve 50 to control around 5.6K exit superheat degree. The indoor blower 68 remains off, while the first electronic expansion valve 41 controls an optimum subcooling degree out of the outdoor air coil 71, which operates as a condenser with the outdoor fan 69 driving a target air flow rate. The indoor coil 70 and the suction line accumulator 38 operates as a charge buffer. The chilled water stores cooling energy in the PCM storage module 46. The same mode and flow path can defrost the outdoor coil, e.g., obtaining energy from the PCM rather than indoor air to eliminate the cold blow of a typical heat pump during defrosting operations. Alternatively, the same mode and flow path can provide simultaneous space cooling and cooling energy-charge with the indoor blower 68 on.

[0027] In a cooling storage discharge mode (FIG. 4), the refrigerant-to-water heat exchanger operates as a condenser to melt the PCM. The indoor blower 68 is on and the indoor air coil 70 operates as an evaporator, with its upstream electronic expansion valve 41 being used to control around 5.6K superheat degree. The outdoor blower 69 is off, while the second expansion valve 43 controls an optimum subcooling degree out of the refrigerant-to-water heat exchanger 44. In the space heating mode (FIG. 5), the indoor coil 70 operates as a condenser and the outdoor coil 71 also acts as an evaporator. The second electronic expansion valve 43 controls an optimum subcooling degree while storing extra refrigerant in the suction line accumulator. In addition, the refrigerant flow to the refrigerant-to-water heat exchanger 44 is turned off by the third expansion valve 50. The water flow is generally off but can run occasionally to maintain the temperature of the phase change material in the hydronic loop 42 above freezing.

[0028] In a heating energy charge mode (FIG. 6), the refrigerant-to-water heat exchanger 44 operates as a condenser to heat water and to store energy in the PCM, and the outdoor coil 71 operates as an evaporator to absorb heat from the outside air. The second electronic expansion valve 43 controls around 5.6K superheat degree exiting the outdoor coil 71. The indoor coil 70 remains off, and the first electronic expansion valve 41 controls an optimum subcooling degree out of the condenser 44. The indoor coil 70 and the suction line accumulator 38 provide a charge buffer. Lastly, in a heating storage discharge mode (FIG. 7), the refrigerant-to-water heat exchanger 44 operates as an evaporator, circulating chilled water and exchanging energy with the PCM. The third expansion valve 50 controls a 5.6K superheat degree out of the evaporator, while the indoor coil 70 operates as a condenser with the indoor blower 68 driving a target indoor air flow rate and delivering heating capacity to the indoor space. The outdoor fan 69 is off, with the second expansion valve 43 controlling an optimum subcooling degree out of the condenser 70. In this mode of operation, the outdoor coil 71 and the suction line accumulator 38 provide a charge buffer.

[0029] In certain modes of operation, water within the hydronic loop 42 transfers heat to and from the PCM (contained within the PCM storage module 46) to absorb or release significant amounts of heat during a phase transition of the PCM, such as changing from a solid to a liquid or vice versa. That is, the PCM absorbs or releases heat during its phase transition, helping to store or release energy. Suitable PCMs can include, for example, water, glycerol, salt hydrates, or paraffin wax, by non-limiting example. Glycerol can also be mixed with water or used in its pure form, having a relatively low melting point. Salt hydrates can include for example sodium sulfate decahydrate and magnesium sulfate heptahydrate. Other PCMs can be used in other embodiments as desired, and the present invention is not limited to a particular PCM. The PCM storage module 46 is optionally a PCM storage tank or PCM panels in building floors, walls, or drop ceilings.

[0030] To reiterate, the control circuitry 60 is communicatively coupled with the four-way reversing valves 40, 52, the electronic expansion valves 41, 43, 50, the pump 48, and the blower fans 68, 69 to cause the ASHP 30 to operate across each of the six modes of operation described above. Generally, the control circuitry 60 selects among the six available modes of operation based on the existing heating and/or cooling demand(s). The control circuitry 60 alters the flow direction by modulating the first reversing valve 40 and by modulating the second reversing valve 52. In particular, the control circuitry 60 can be communicatively coupled with or integrated into a user interface, for example a digital thermostat, that is configured to receive a user selection of a desired indoor temperature. The control circuitry 60 causes the multi-functional system to provide the appropriate mode of operation to meet the selected indoor air temperature: (1) space cooling mode, (2) dedicated cooling-energy charge, simultaneous space cooling and cooling-energy charge, and heating mode outdoor defrost mode; (3) cooling storage discharge mode; (4) space heating mode; (5) heat energy charge mode; and (6) heating storage discharge mode.

[0031] The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to elements in the singular, for example, using the articles a, an, the, or said, is not to be construed as limiting the element to the singular.