Heat Pump Technology with Refrigerant-Based Thermal Storage

Abstract

A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building. The heat pump includes an indoor coil having the refrigerant flow therethrough and transfer heat with the interior of the building and an outdoor coil having the refrigerant flow therethrough and transfer heat with the exterior of the building. The heat pump includes first and second fluid paths each extending between the indoor coil and the outdoor coil and a domestic hot water tank having a cold-water supply section and a hot-water supply section. The heat pump includes a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path and a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path.

Claims

1. A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a domestic hot water tank having a cold-water supply section and a hot-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; and a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path.

2. The heat pump of claim 1, further comprising a compressor defining a portion of to the second fluid path for moving the refrigerant through the heat pump.

3. The heat pump of claim 2, wherein the compressor defines a portion of the second fluid path between the outdoor coil and the second coil.

4. The heat pump of claim 1, further comprising a blower configured to flow air across the indoor coil for transferring heat between the refrigerant and the air.

5. The heat pump of claim 1, further comprising a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

6. The heat pump of claim 5, further comprising a thermal storage tank bypass line defining a portion of the first fluid path around the thermal storage tank for selectively bypassing use of thermal storage tank.

7. The heat pump of claim 5, wherein the thermal storage tank comprises a housing defining an interior for holding a phase change material and an internal coil for flowing the refrigerant therethrough, the internal coil disposed within the interior and in contact the phase change material to cause heat transfer between the refrigerant and the phase change material.

8. The heat pump of claim 1, further comprising a diverting valve defining a portion of the second fluid path and configured to alternate flow of the refrigerant through the heat pump between a first direction and a second direction, opposite the first direction.

9. The heat pump of claim 8, further comprising a first expansion valve defining a portion of the first fluid path adjacent the indoor coil and causing at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas.

10. The heat pump of claim 8, further comprising a second expansion valve defining a portion of the first fluid path adjacent the outdoor coil and causing at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas.

11. The heat pump of claim 8, further comprising a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path when the refrigerant is flowing the in the first direction.

12. The heat pump of claim 11, further comprising a third expansion valve defining a portion of the first fluid path adjacent the thermal storage tank and causing at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas.

13. The heat pump of claim 12, further comprising a fourth expansion valve defining a portion of the first fluid path adjacent the thermal storage tank and causing at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas.

14. The heat pump of claim 1, further comprising a first bypass line defining a portion of the first fluid path around the first coil for selectively bypassing use of the first coil.

15. The heat pump of claim 1, further comprising a second bypass line defining a portion of the second fluid path around the second coil for selectively bypassing use of the second coil.

16. The heat pump of claim 1, further comprising an indoor coil bypass line adjacent the indoor coil and extending across the indoor coil between the first fluid path and the second fluid path to selectively bypass use of the indoor coil.

17. The heat pump of claim 1, further comprising an outdoor coil bypass line adjacent the outdoor coil and extending across the outdoor coil between the first fluid path and the second fluid path to selectively bypass use of the outdoor coil.

18. A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a compressor defining a portion of to the second fluid path for moving the refrigerant through the heat pump; a blower configured to flow air across the indoor coil for transferring heat between the refrigerant and the air; a domestic hot water tank having a cold-water supply section and a hot-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path; and a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

19. The heat pump of claim 18, further comprising a diverting valve defining a portion of the second fluid path and configured to alternate flow of the refrigerant through the heat pump between a first direction and a second direction, opposite the first direction.

20. A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a domestic hot water tank having a cold-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; and a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0010] FIG. 1 depicts a schematic illustration of a heat pump, according to one or more embodiments shown and described herein;

[0011] FIG. 2 depicts a schematic illustration of a domestic hot water tank of the heat pump of FIG. 1, according to one or more embodiments shown and described herein;

[0012] FIG. 3 depicts a schematic illustration of another embodiment of the heat pump, according to one or more embodiments shown and described herein; and

[0013] FIG. 4 depicts a table describing modes of operation of the heat pump, according to one or more embodiments shown and described herein.

DETAILED DESCRIPTION

[0014] Embodiments described herein are generally directed to a heat pump for transporting heat with a refrigerant between an interior and an exterior of a building. The heat pump may include an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building. The heat pump may include an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building. The heat pump may include a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil and a domestic hot water tank having a cold-water supply section and a hot-water supply section. The heat pump may include a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path and a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path.

[0015] The heat pumps described herein may be particularly useful for residential applications, but may be applicable to non-residential applications. Improving the efficiency and demand flexibility of these heat pump can lead to reduced energy consumption, costs, and gas emissions, leading to notable environmental and economic benefits. Heat pumps have emerged as a cost-effective solution for reducing energy consumption, costs, and gas emissions, which leads to environmental and economic benefits. However, electric energy consumption of the heat pumps poses a new pressure on the electric grid, and in colder climates, the efficiency and capacity of heat pumps can drop significantly with lower outside air temperatures. The embodiments described herein overcome these limitations by utilizing heat from the domestic hot water tank, such as within the home, to add heat into the system when heating the home, improving the efficiency of the heat pump. When the heat pump is utilized for cooling the home, heat transferred into the system may be used to provide supplemental heating to the domestic hot water tank, improving the efficiency of the domestic hot water tank. Various embodiments of the heat pump and the operation of the heat pump is described in more detail herein. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0016] As used herein, the singular forms a, an and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a component includes aspects having two or more such components, unless the context clearly indicates otherwise.

[0017] Referring now to the drawings, FIG. 1 schematically depicts an exemplary embodiment of a heat pump 20 for transporting heat with a refrigerant between an interior 22 and an exterior 24 of a building 26. In one example, the refrigerant is 1,1,1,2-tetrafluoroethane (R134a). However, the refrigerant may be any fluid capable of undergoing repeated phase changes between a liquid and a gas.

[0018] The heat pump 20 may include an indoor coil 28 disposed within the interior 22 of the building 26. The indoor coil 28 is configured to have the refrigerant flow therethrough and transfer heat with the interior 22 (such as the interior atmosphere, floor, or other structures) of the building 26. For example, the indoor coil 28 may be a heat exchanger having a plurality of fins coupled thereto that increase the surface area of the indoor coil 28 that is in contact with air circulating within the interior 22 of the building 26, thereby efficiently transferring heat between the refrigerant and the air. However, the indoor coil 28 may have any suitable configuration for transferring heat.

[0019] The heat pump 20 may further include a blower 30 configured to flow or circulate air across the indoor coil 28 for transferring heat between the refrigerant and the air. More specifically, the blower 30 moves and directs the air within the interior 22 of the building 26 across the indoor coil 28 to facilitate convective heat transfer between the indoor coil 28 and the air.

[0020] The heat pump 20 further includes an outdoor coil 32 disposed in the exterior 24 of the building 26. The outdoor coil 32 is configured to have the refrigerant flow therethrough and transfer heat with the exterior 24 of the building 26. The outdoor coil 32 may be a heat exchanger having a plurality of fins coupled thereto that increase the surface area of the outdoor coil 32 that is in contact with the air outside of the building 26, thereby efficiently transferring heat between the refrigerant and the air. However, the outdoor coil 32 may have any suitable configuration for transferring heat.

[0021] The heat pump 20 may include a fan 34 configured to flow air across the outdoor coil 32 for transferring heat between the refrigerant and the outside air. More specifically, the fan 34 moves and directs the air outside of the building 26 across the outdoor coil 32 to facilitate convective heat transfer between the outdoor coil 32 and the outside air.

[0022] The heat pump 20 may include a first fluid path 36 and a second fluid path 38 each extending between the indoor coil 28 and the outdoor coil 32. The first fluid path 36 and the second fluid path 38 collectively form a circuit through which the refrigerant flows between the indoor coil 28 and the outdoor coil 32. The first fluid path 36 and the second fluid path 38 may include components that will be described in detail below that are connected by tubing, hosing, pipes, or the like.

[0023] The heat pump 20 may include a compressor 40 defining a portion of the second fluid path 38 for moving the refrigerant through the heat pump 20 (e.g., through the first fluid path 36, the second path, the indoor coil 28, the outdoor coil 32, etc.). The compressor 40 may be configured as a rotary compressor, scroll compressor, or any other suitable compressor configuration. Further, the compressor 40 contemplated herein is electrically powered. However, the compressor 40 may be powered by hydraulics, pneumatics, or in any other suitable manner.

[0024] The heat pump 20 may include a diverting valve 42 defining a portion of the second fluid path 38 and configured to alternate flow of the refrigerant through the heat pump 20 between a first direction and a second direction, opposite the first direction. The first direction refers to the refrigerant flowing from the compressor 40 through the second fluid path 38 to the indoor coil 28, then out of the indoor coil 28 and through the first fluid path 36 to the outdoor coil 32 (i.e., counterclockwise with reference to FIG. 1). The second direction refers to the refrigerant flowing from the compressor 40 through the outdoor coil 32, then through the first fluid path 36 to the indoor coil 28, then out of the indoor coil 28 and through the second fluid path 38 (i.e., clockwise with reference to FIG. 1).

[0025] The heat pump 20 may include a thermal storage tank 44 defining a portion of the first fluid path 36. The thermal storage tank 44 is configured to receive and store heat from the refrigerant in the first fluid path 36. The thermal storage tank 44 includes a housing 46 defining an interior for holding a phase change material 48 and an internal coil 50 for flowing the refrigerant therethrough. The phase change material 48 may be any material or composition of the materials capable of absorbing and retaining heat therein. For example, the phase change material 48 may be water, paraffins, salts, salt hydrates, metal alloys, etc.

[0026] The internal coil 50 is disposed within the interior of the housing 46 and in contact the phase change material 48 dispersed around the internal coil 50 to cause heat transfer between the refrigerant and the phase change material 48. Therefore, as refrigerant flows through the internal coil 50, the heat carried by the refrigerant is transferred to the internal coil 50, which in turn transfers the heat to the phase change material 48 through contact with the phase change material 48. It is to be appreciated that in certain conditions (as will be described below) the opposite may be true. More specifically, the thermal storage tank 44 is configured to receive and store heat from the refrigerant in the first fluid path 36 when the refrigerant is flowing the in the first direction. On the other hand, the thermal storage tank 44 is configured to transfer the heat from the phase change material 48 into the refrigerant in the first fluid path 36 when the refrigerant is flowing in the second direction.

[0027] The heat pump 20 may include a thermal storage tank bypass line 52 defining a portion of the first fluid path 36 around the thermal storage tank 44 for selectively bypassing use of the thermal storage tank 44. More specifically, the thermal storage tank bypass line 52 provides an alternate path around the thermal storage tank 44 that may be selectively utilized to bypass flow of the refrigerant through the thermal storage tank 44, as will be described in greater detail below.

[0028] The heat pump 20 may include a domestic hot water tank 54 having a cold-water supply section 56 and a hot-water supply section 57. The cold-water supply section 56 receives and stores water received from a supply source (i.e., water from a water main, a well, etc.) The water in the cold-water supply section 56 is provided to the hot-water supply section 57 on demand as hot water is used within the building, depleting the hot-water supply section 57. The water that enters the hot-water supply section 57 is then heated and stored in the hot-water supply section 57 to provide hot water to the building. The hot-water supply section 57 may be warmed by a heater 58 (see FIG. 2), which may include a combustion heater (e.g., a natural gas, liquid propane, fuel oil, etc.), an electric heater, or any suitable manner of heating.

[0029] The heat pump 20 may include a first coil 60 disposed in the cold-water supply section 56 of the domestic hot water tank 54 and defining a portion of to the first fluid path 36. The first coil 60 is configured to transfer heat between the refrigerant and the water in the cold-water supply section 56. As will be described in greater detail below, in one configuration the water in the cold-water supply section 56 is colder than the refrigerant in the first coil 60, thereby moving heat from the refrigerant to the water, thereby raising the temperature of the water, and improving the operating efficiency of the domestic hot water tank 54.

[0030] Similarly, the heat pump 20 may include a second coil 62 disposed in the hot-water supply section 57 of the domestic hot water tank 54 and defining a portion of to the second fluid path 38. The second coil 62 is configured to transfer heat between the refrigerant and the water in the hot-water supply section 57. As will be described in greater detail below, in one configuration the water in the hot-water supply section 57 is colder than the refrigerant in the first coil 60, thereby moving heat from the refrigerant to the water, thereby causing the temperature of the water to rise and improving the operating efficiency of the domestic hot water tank 54. In another configuration, the water in the hot-water supply section 57 is warmer than the refrigerant in the first coil 60, thereby moving heat from the water to the refrigerant. The separation of the water in the cold-water supply section 56 from the water in the hot-water supply section 57 may improve the efficiency in the heat transfer with the first coil 60 and the second coil 62, respectively.

[0031] As shown in FIG. 1, the first coil 60 defines a portion of the first fluid path 36 between the indoor coil 28 and the outdoor coil 32. The second coil 62 defines a portion of the second fluid path 38 between the indoor coil 28 and the outdoor coil 32. Moreover, the compressor 40 defines a portion of the second fluid path 38 between the outdoor coil 32 and the second coil 62. In FIG. 1, the cold-water supply section 56 and the hot-water supply section 57 of the domestic hot water tank 54 are shown to be spaced from one another. However, this is for schematic purposes to clearly illustrate the flow paths of the refrigerant. FIG. 2 provides an illustration of an embodiment of the domestic hot water tank 54 where the cold-water supply section 56 and the hot-water supply section 57 are assembled as a unit. It is to be appreciated that domestic hot water tank 54 may have any suitable configuration.

[0032] With reference to FIG. 1, the heat pump 20 may further include a first expansion valve EV1, a second expansion valve EV2, and a third expansion valve EV3 that each reduce the pressure of the refrigerant flowing therethrough to at least a portion of the refrigerant to phase change from a liquid to a gas. More specifically, the first expansion valve EV1 defines a portion of the first fluid path 36 adjacent the indoor coil 28 and causes at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas. Moreover, the first expansion valve EV1 reduces the pressure of the refrigerant in the indoor coil 28 so that all the refrigerant will evaporate. The heat pump 20 further includes a first check valve CV1 that bypasses flow around the first expansion valve EV1 in the first direction while restricting flow therethrough in the second direction to direct the refrigerant through the first expansion valve EV1.

[0033] The second expansion valve EV2 defines a portion of the first fluid path 36 adjacent the outdoor coil 32 and causes at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas. The heat pump 20 further includes a second check valve CV2 that bypasses flow around the second expansion valve EV2 in the second direction while restricting flow therethrough in the first direction to direct the refrigerant through the second expansion valve EV2.

[0034] The third expansion valve EV3 defines a portion of the first fluid path 36 adjacent the thermal storage tank 44 and causes at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas. The heat pump 20 further includes a third check valve CV3 that bypasses flow around the third expansion valve EV3 in the second direction while restricting flow therethrough in the first direction to direct the refrigerant through the third expansion valve EV3.

[0035] The heat pump 20 may include a first bypass line 64, a second bypass line 66, an indoor coil bypass line 68, and an outdoor coil bypass line 70. The first bypass line 64 defines a portion of the first fluid path 36 around the first coil 60 for selectively bypassing use of the first coil 60. The second bypass line 66 defines a portion of the second fluid path 38 around the second coil 62 for selectively bypassing use of the second coil 62. The indoor coil bypass line 68 is disposed adjacent the indoor coil 28 and extends across the indoor coil 28 between the first fluid path 36 and the second fluid path 38 to selectively bypass use of the indoor coil 28. The outdoor coil bypass line 70 is adjacent the outdoor coil 32 and extends across the outdoor coil 32 between the first fluid path 36 and the second fluid path 38 to selectively bypass use of the outdoor coil 32.

[0036] The heat pump 20 may include a first solenoid valve SV1, a second solenoid valve SV2, a third solenoid valve SV3, a fourth solenoid valve SV4, a fifth solenoid valve SV5, a sixth solenoid valve SV6, a seventh solenoid valve SV7, an eighth solenoid valve SV8, a ninth solenoid valve SV9, and a tenth solenoid valve SV10. The solenoid valves SV1-SV10 may be actuated by an electronic control unit, a manual switch, or any other suitable manner. A greater or fewer number of valves may be included without departing from the scope of the present disclosure. Moreover, while solenoid valves are indicated other valve types may be used (e.g., ball valves, plug valves, disc valves, gate valves, globe valves, needles valves, etc.).

[0037] The first solenoid valve SV1 is disposed on the second bypass line 66, actuation of which allows the selective bypassing of the second coil 62. The second solenoid valve SV2 is disposed adjacent an entrance of the second coil 62 in the first direction, actuation of which selectively permits flow of the refrigerant into the second coil 62. The third solenoid valve SV3 is disposed adjacent an entrance of the indoor coil 28 in the first direction, actuation of which selectively permits flow of the refrigerant into the indoor coil 28. The fourth solenoid valve SV4 is disposed on the indoor coil bypass line 68, actuation of which allows the selective bypassing of the indoor coil 28. The fifth solenoid valve SV5 is disposed adjacent an entrance of the first coil 60 in the first direction, actuation of which selectively permits flow of the refrigerant into the first coil 60.

[0038] The sixth solenoid valve SV6 is disposed on the first bypass line 64, actuation of which allows the selective bypassing of the first coil 60. The seventh solenoid valve SV7 is disposed adjacent an entrance of the internal coil 50 of the thermal storage tank 44 in the first direction, actuation of which selectively permits flow of the refrigerant into the internal coil 50. The eighth solenoid valve SV8 is disposed on the thermal storage tank bypass line 52, actuation of which allows the selective bypassing of the indoor coil 28. The ninth solenoid valve SV9 is disposed on the outdoor coil bypass line 70, actuation of which allows the selective bypassing of the outdoor coil 32. The tenth solenoid valve SV10 is disposed adjacent an entrance of the outdoor coil 32 in the first direction, actuation of which selectively permits flow of the refrigerant into the outdoor coil 32. Accordingly, the solenoid valves SV1-SV10 collectively direct the flow of the refrigerant through the heat pump 20. Therefore, the heat pump 20 can be operated in various different modes. For example, in one mode, the heat pump 20 may operate in a traditional configuration where heat is absorbed at the outdoor coil 32 and moved to the indoor coil 28 where the heat is released into the air of the interior 22 of the building 26. In another mode, heat stored within the thermal storage tank 44 may be discharge therefrom and be the sole source of heat provided to the indoor coil 28. In another mode, the water in the hot-water supply section 57 of the domestic hot water tank 54 (heated by the heater 58) may be the sole source of heat provided to the indoor coil 28. In another mode, the thermal storage tank 44 and the hot-water supply section 57 may collectively provide heat to the indoor coil 28. The various modes of the heat pump 20 will be described in greater detail below.

[0039] Moreover, the supplemental heat provided by the domestic hot water tank 54 to the heat pump 20 may reduce or eliminate the need for a supplemental air-to-combustion heat exchanger within the building 26, as is often used in typical heat pump configurations. More specifically, the domestic hot water tank 54 is consistently maintains a high temperature of the water in the hot-water supply section 57 (by heating from the heater 58) for demand-based use at plumbing fixtures within the building 26. Therefore, the domestic hot water tank 54 may provide a consistent and efficient source of heat to the heat pump 20. Furthermore, with reference to FIG. 1, the heat pump may include a demand line 72 that extends between the first fluid path 36 and the second fluid path 38. More specifically, the demand line 72 connects to the first fluid path 36 between the cold-water supply section 56 and the first expansion valve EV1 and connects to the second fluid path 38 adjacent an inlet to the second coil 62. The heat pump may further include a demand pump 74 connected to the demand line 72. The demand pump 74 forces refrigerant through the demand line 72, which optimizes the flow of refrigerant between the indoor coil 28 and the second coil 62. Therefore, when supplemental heat is required from the hot-water supply section 57 in order to meet the desired temperature within the building 26, the demand pump 74 ensures sufficient flow of refrigerant to the second coil 62 to meet the demand.

[0040] FIG. 3 schematically depicts another exemplary embodiment of the heat pump 20. The embodiment of the heat pump 20 in FIG. 3 is similar in configuration to the heat pump 20 of FIG. 1, but for the heat pump 20 further includes a fourth expansion valve EV4 defining a portion of the first fluid path 36 adjacent the thermal storage tank 44 and causing at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas. Moreover, the fourth expansion valve EV4 reduces the pressure of the refrigerant within the internal coil 50 of the thermal storage tank 44, causing all of the refrigerant to evaporate and allow heat to transfer from the phase change material 48 to the refrigerant. In one mode of operation, the fourth expansion valve EV4 allows for defrosting the outdoor coil 32, which is described in greater detail below. The heat pump 20 further includes a fourth check valve CV4 that bypasses flow around the fourth expansion valve EV4 in the first direction while restricting flow therethrough in the second direction to direct the refrigerant through the fourth expansion valve EV4.

[0041] The operation of the heat pump 20 will now be described with reference to the table shown in FIG. 4. The table in FIG. 4 lists twelve potential modes of operation of the heat pump 20 are shown in the first column (See N #1 through N #12). The second column lists the state of the indoor coil 28 for each of the modes and whether the indoor coil 28 is heating the air, cooling the air, or is off (i.e., no heat transfer). The third column lists whether the domestic hot water tank 54 is being heated by the heater 58 for each of the modes. The fourth, fifth, and sixth columns list whether refrigerant passes through the cold-water supply section 56, the thermal storage tank 44, and the hot-water supply section 57, respectively, for each of the modes. The seventh column lists the general seasons for use of each of the modes. The eighth column lists an operation mode classification for each of the modes. The ninth column lists a purpose for each of the modes. The tenth column lists which of the solenoid valves (SV1-SV10) are open for each of the modes. The eleventh column lists which of the expansion valves (EV1-EV4) are open for each of the modes. The operation described below and shown in the table of FIG. 4 is applicable to the embodiments of the heat pump 20 shown in FIGS. 1 and 3, unless said otherwise.

[0042] During the summer season (i.e., high outside temperature), the heat pump 20 operates either in heating (i.e., refrigerant flow in the first direction) to heat the domestic hot water tank 54 (see N #4) or in cooling (i.e., refrigerant flow in the second direction) to cool the interior 22 of the building (see N #1), cool (i.e., remove heat from) the thermal storage tank 44 (see N #2), or cool the interior 22 of the building but using the thermal storage tank 44 as a subcooling medium (see N #3). When the heat pump 20 cools the interior 22 of the building (see N #1), the high-pressure liquid refrigerant from the outdoor coil 32 is subcooled in the thermal storage tank 44, melting the phase change material 48 (e.g., assuming phase material at 55 F.) and consequently increasing the cooling effect of the refrigerant. The refrigerant is then further subcooled in the cold-water supply section 56 of the domestic hot water tank 54, preheating the cold water in the cold-water supply section 56. The extra cooling effect on the interior 22 of the building is equal to the heat absorbed in the cold-water supply section 56. The first expansion valve EV1 drops the refrigerant pressure to an evaporator pressure level in the indoor coil 28. In one example, if the water in the cold-water supply section 56 is about 60 F., the liquid refrigerant could be subcooled to around this temperature. Overtime, if there is no hot water demand from the domestic hot water tank 54, the water temperature of the cold-water supply section 56 will be heated to around a condenser water temperature (e.g., around 100 F.). When there is no hot water demand, the high-pressure liquid refrigerant will only be subcooled in the thermal storage tank 44 to increase the cooling effect until all the phase change material 48 is melted. At night, in the summer (when the outside air temperature is lower), the heat pump 20 will operate only to charge (i.e., cool) the thermal storage tank 44 (see N #2), that in turn will be used to subcool the liquid refrigerant (see N #3). The solenoid valves (SV1-SV10) will open or close based on operation mode as listed in the table.

[0043] In summer season or winter season, if there is a demand for hot water, the heat pump 20 will operate in heating (see N #4), moving the heat from the outdoor coil 32 to the hot-water supply section 57 of the domestic hot water tank 54. In that case, the tenth solenoid valve SV10, the eighth solenoid valve SV8, the fifth solenoid valve SV5, the fourth solenoid valve SV4, and the second solenoid valve SV2 will open and the ninth solenoid valve SV9, the seventh solenoid valve SV7, the sixth solenoid valve SV6, the third solenoid valve SV3, and the first solenoid valve SV1 will close. The second expansion valve EV2 will drop the pressure of the refrigerant to an evaporator pressure level in the outdoor coil 32. The high-pressure liquid refrigerant leaving the hot-water supply section 57 of the domestic hot water tank 54 will be subcooled in the cold-water supply section 56 of the domestic hot water tank 54. At elevated outside air temperatures (during the summer season), the heat pump 20 will operate at maximum capacity to heat the water in hot-water supply section 57 due to very low lift. Therefore, the required water temperature will be met very quickly and then the heat pump 20 will switch back to cooling if needed. The heater 58 in the domestic hot water tank 54 could be used instead if high cooling demand is required.

[0044] In the winter season, the heat pump 20 operates as a typical heat pump 20 to provide heating to the interior 22 of the building (see N #5). In that case, the first solenoid valve SV1, the third solenoid valve SV3, the sixth solenoid valve SV6, the seventh solenoid valve SV7, and the tenth solenoid valve SV10 are open while the second solenoid valve SV2, the fourth solenoid valve SV4, the eighth solenoid valve SV8, and the ninth solenoid valve SV9 will be closed. The liquid refrigerant from the indoor coil 28 will be subcooled in the cold-water supply section 56 of the domestic hot water tank 54. Overtime, if there is no water demand from the domestic hot water tank 54, the water temperature will rise until the liquid refrigerant and the water are balanced at a saturated refrigerant temperature (e.g., approximately 95 F.), providing free heat to the refrigerant as the water is used in any event within the building. If both, the interior 22 of the building and the domestic hot water tank 54 require heat (see N #6), the second solenoid valve SV2, the third solenoid valve SV3, the sixth solenoid valve SV6, the seventh solenoid valve SV7, and the tenth solenoid valve SV10 will open while the first solenoid valve SV1 and the fourth solenoid valve SV4, the eighth solenoid valve SV8, and the ninth solenoid valve SV9 will close. If the water temperature is not met, the third solenoid valve SV3 could close and the fourth solenoid valve SV4 could open for a short of time to meet demand.

[0045] In cold weather, when the heat pump 20 cannot meet the heating loads, the heater 58 in the domestic hot water tank 54 will add heat to maintain the water temperature in the hot-water supply section 57 (e.g., to approximately 120 F.), thus superheating the gaseous refrigerant gas in the hot-water supply section 57. This will supply enough hot gaseous refrigerant to the indoor coil 28 and/or second coil 62 (see N #7, N #8, or N #9). When the outside air temperature drops below the temperature of the phase change material 48 of the thermal storage tank 44 (e.g. 32 F. if water is used), the heat pump 20 will operate to heat the interior 22 of the building but the thermal storage tank 44 will act as an evaporator (i.e., a heat source) as shown in N #10. The ninth solenoid valve SV9 and the seventh solenoid valve SV7 will open while the tenth solenoid valve SV10 will close. The third expansion valve EV3 at the inlet of the thermal storage tank 44 will be used to drop the pressure of the refrigerant. If water is used as the phase change material 48 in the thermal storage tank 44, the heat pump 20 will operate until all of the water phase change material 48 turns to ice with a sink temperature of approximately 32 F. instead of the cold outside air temperature (e.g., 5 F.) and the theoretical coefficient of performance increases significantly. When the temperature of the thermal storage tank 44 drops below 32 F. indicating that all of the water phase change material 48 has become ice, the heat pump 20 will switch back to operate normally and the outdoor coil 32 will function as an evaporator (see N #8 and N #9). As the liquid refrigerant coming from the indoor coil 28 is warm, it will be subcooled by the cold-water supply section 56 and the thermal storage tank 44, thus melting the ice of the phase change material 48. After all ice has melted, the heat pump 20 will then operate using the thermal storage tank 44 as a heat source.

[0046] During very cold weather, as illustrated in N #11, the compressor 40 will shut down, and heating of the interior 22 will be provided by the heater 58 in the domestic hot water tank 54. More specifically, the demand pump 74 will activate, transferring liquid refrigerant from the first fluid path 36 directly to the second coil 62, where the refrigerant will evaporate into gas heat from the heater 58. The gaseous refrigerant will then condense in the indoor coil 28, releasing heat into the air of the interior 22. In this mode, only the third solenoid valve SV3 will remain open, while all other solenoid valves will be closed. The heat pump 20 can operate to support the heater 58 to heat the interior 22, as illustrated in N #9. In this mode, the first solenoid valve SV1, the third solenoid valve SV3, the sixth solenoid valve SV6, the seventh solenoid valve SV7, and the tenth solenoid valve SV10 will be open. The demand pump 74 will circulate a portion of the liquid refrigerant to second coil 62 of the domestic hot water tank 54, while the remaining liquid refrigerant continues to the outdoor coil 32. In that case, the compressor 40 will turn on to provide additional heat from outdoor coil 32.

[0047] Moreover, in cold weather, when the heat pump 20 is operating to the heat the interior 22 of the building, the outdoor coil 32 operating as an evaporator will absorb heat from the outside air, causing moisture in the air to freeze on the outdoor coil 32. The embodiment of the heat pump 20 shown in FIG. 3 provides a mode to defrost the outdoor coil 32. To defrost the outdoor coil 32 (see N #12), the tenth solenoid valve SV10, the seventh solenoid valve SV7, the sixth solenoid valve SV6, the fourth solenoid valve SV4, and the first solenoid valve SV1 will open and the ninth solenoid valve SV9, the eighth solenoid valve SV8, the fifth solenoid valve SV5, the third solenoid valve SV3, and the second solenoid valve SV2 will close. The fourth expansion valve EV4 allows for a pressure drop of the refrigerant flowing into the thermal storage tank 44, allowing the refrigerant to absorb heat from the phase change material 48 of the thermal storage tank 44. The heat absorbed in the refrigerant in-turn defrosts the outdoor coil 32.

[0048] While the heat pump 20 shown in the Figures and described herein is configured for use with a residential home, the heat pump 20 may be configured for use as a rooftop unit on a commercial or multi-dwelling building. In such an embodiment, the first coil 60 would be positioned within an outdoor air intake for the building while the second coil 62 would be positioned within an air exhaust of the building. Alternatively, the first coil 60 may be positioned within air exhaust for the building while the second coil 62 may be positioned within the outdoor air intake of the building. It is to be appreciated that the heat pump 20 may have any reasonable configuration for use with a rooftop unit.

[0049] From the above, it is to be appreciated that defined herein are heat pumps for transporting heat with a refrigerant between an interior and an exterior of a building. The heat pump may include an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building. The heat pump may include an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building. The heat pump may include a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil and a domestic hot water tank having a cold-water supply section and a hot-water supply section. The heat pump may include a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path and a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path.

[0050] The embodiments described herein utilize heat from the domestic hot water tank within the home to add heat into the refrigerant when heating the home, improving the efficiency of the heat pump. When the heat pump is utilized for cooling the home, heat transferred into the refrigerant may be used to provide supplemental heating to the domestic hot water tank, improving the efficiency of the domestic hot water tank.

[0051] Further aspects of the embodiments described herein are provided by the subject matter of the following clauses:

[0052] A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a domestic hot water tank having a cold-water supply section and a hot-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; and a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path.

[0053] The heat pump of any preceding clause, further comprising a compressor defining a portion of to the second fluid path for moving the refrigerant through the heat pump.

[0054] The heat pump of any preceding clause, wherein the compressor defines a portion of the second fluid path between the outdoor coil and the second coil.

[0055] The heat pump of any preceding clause, further comprising a blower configured to flow air across the indoor coil for transferring heat between the refrigerant and the air.

[0056] The heat pump of any preceding clause, further comprising a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

[0057] The heat pump of any preceding clause, further comprising a thermal storage tank bypass line defining a portion of the first fluid path around the thermal storage tank for selectively bypassing use of thermal storage tank.

[0058] The heat pump of any preceding clause, wherein the thermal storage tank comprises a housing defining an interior for holding a phase change material and an internal coil for flowing the refrigerant therethrough, the internal coil disposed within the interior and in contact the phase change material to cause heat transfer between the refrigerant and the phase change material.

[0059] The heat pump of any preceding clause, further comprising a diverting valve defining a portion of the second fluid path and configured to alternate flow of the refrigerant through the heat pump between a first direction and a second direction, opposite the first direction.

[0060] The heat pump of any preceding clause, further comprising a first expansion valve defining a portion of the first fluid path adjacent the indoor coil and causing at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas.

[0061] The heat pump of any preceding clause, further comprising a second expansion valve defining a portion of the first fluid path adjacent the outdoor coil and causing at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas.

[0062] The heat pump of any preceding clause, further comprising a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path when the refrigerant is flowing the in the first direction.

[0063] The heat pump of any preceding clause, further comprising a third expansion valve defining a portion of the first fluid path adjacent the thermal storage tank and causing at least a portion of the refrigerant flowing in the first direction to phase change from a liquid to a gas.

[0064] The heat pump of any preceding clause, further comprising a fourth expansion valve defining a portion of the first fluid path adjacent the thermal storage tank and causing at least a portion of the refrigerant flowing in the second direction to phase change from a liquid to a gas.

[0065] The heat pump of any preceding clause, further comprising a first bypass line defining a portion of the first fluid path around the first coil for selectively bypassing use of the first coil.

[0066] The heat pump of any preceding clause, further comprising a second bypass line defining a portion of the second fluid path around the second coil for selectively bypassing use of the second coil.

[0067] The heat pump of any preceding clause, further comprising an indoor coil bypass line adjacent the indoor coil and extending across the indoor coil between the first fluid path and the second fluid path to selectively bypass use of the indoor coil.

[0068] The heat pump of any preceding clause, further comprising an outdoor coil bypass line adjacent the outdoor coil and extending across the outdoor coil between the first fluid path and the second fluid path to selectively bypass use of the outdoor coil.

[0069] A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a compressor defining a portion of to the second fluid path for moving the refrigerant through the heat pump; a blower configured to flow air across the indoor coil for transferring heat between the refrigerant and the air; a domestic hot water tank having a cold-water supply section and a hot-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; a second coil disposed in the hot-water supply section of the domestic hot water tank and defining a portion of to the second fluid path; and a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

[0070] The heat pump of any preceding clause, further comprising a diverting valve defining a portion of the second fluid path and configured to alternate flow of the refrigerant through the heat pump between a first direction and a second direction, opposite the first direction.

[0071] A heat pump for transporting heat with a refrigerant between an interior and an exterior of a building, the heat pump comprising: an indoor coil configured to have the refrigerant flow therethrough and transfer heat with the interior of the building; an outdoor coil configured to have the refrigerant flow therethrough and transfer heat with the exterior of the building; a first fluid path and a second fluid path each extending between the indoor coil and the outdoor coil; a domestic hot water tank having a cold-water supply section; a first coil disposed in the cold-water supply section of the domestic hot water tank and defining a portion of to the first fluid path; and a thermal storage tank defining a portion of the first fluid path, wherein the thermal storage tank is configured to receive and store heat from the refrigerant in the first fluid path.

[0072] It is noted that the terms substantially and about may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0073] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.