HEAT PUMP SYSTEM
Provided is a heat pump system (10, 10A) for a conditioned space comprising a first thermal fluid circuit adapted to selectably operate to circulate a thermal fluid therein, and a second thermal fluid circuit adapted to selectably operate to circulate the thermal fluid therein. The first thermal fluid circuit may comprise a compressor (15), a first heat exchanger (11), and a passage (55) of a heat accumulator (50). The second thermal fluid circuit may bypass the first heat exchanger (11), or the passage (55) of the heat accumulator (50), or both. The second thermal fluid circuit may comprise the compressor (15), and a second heat exchanger (12).
The present invention generally relates to a heat pump system. More particularly, the present invention relates to a heat pump system employing a heat accumulator to defrost a heat exchanger in the system. Most particularly, the present invention relates to a heat pump system, where the accumulator obtains waste heat from the compressor in the system.
BACKGROUNDA heat pump is a device that transfers thermal energy from a heat source to a heat sink. Heat pumps can move thermal energy in a direction opposite to the direction of the spontaneous heat flow. A heat pump uses energy to accomplish the desired transfer of thermal energy from heat source to heat sink.
Compressor driven air conditioners are one example of a heat pump; however, the term heat pump is more general and applies to devices which are adapted for use for space heating, or space cooling. When a heat pump is used for heating, it may use the same basic refrigeration cycle employed by an air conditioner or a refrigerator, with the difference that it outputs heat into the conditioned space rather than into the surrounding environment. In this use, heat pumps generally absorb heat from a heat source region, such as, without limitation, cooler external air or from the ground. Heat pumps are sometimes used to provide heating because less high grade (low entropy) energy is required for their operation than appears in the output heat. That is, in a heat pump, much or most of the energy for heating may be absorbed from a heat source region and only a small fraction of the energy for heating needs to come from electricity or some other high grade energy source. Because the heat output to the heat sink may comprise both the heat absorbed from the heat source, and the high grade heat consumed to transfer of thermal energy from heat source region to heat sink region, the heat output may be several times larger than the high grade energy consumed. As a consequence, the system coefficient of performance (COP) of a heat pump may be substantially greater than 1. The system coefficient of performance (COP) of some heat pumps may be 3 or 4.
One issue in operation of known heat pumps is that the heat exchanger absorbing heat from a heat source region may frost when operating in low temperature environments. To defrost the frosted heat exchanger, some heat pumps may stop heating the heat sink region and switch to absorbing heat from the previous heat sink region to provide heat to defrost the frosted heat exchanger. Where the previous heat sink region is a conditioned space that is desirable to heat or keep warm, this removal of heat to defrost the frosted heat exchanger is undesirable and may result in an uncomfortable or undesired decrease in temperature.
SUMMARY OF THE INVENTIONProvided is a heat pump system for a conditioned space comprising a first thermal fluid circuit adapted to selectably operate to circulate a thermal fluid therein, and a second thermal fluid circuit adapted to selectably operate to circulate the thermal fluid therein. The first thermal fluid circuit may comprise a compressor, a first heat exchanger, and a passage of a heat accumulator. The second thermal fluid circuit may bypass the passage of the heat accumulator. The second thermal fluid circuit may comprise the compressor, and a second heat exchanger.
The following description and the annexed drawings set forth in detail certain illustrative aspects of the claimed subject matter. These aspects are indicative, however, of but a few of the various ways in which the principles of the innovation may be employed and the claimed subject matter is intended to include all such aspects and their equivalents. Other advantages and novel features of the claimed subject matter will become apparent from the following detailed description of the innovation when considered in conjunction with the drawings.
DETAILED DESCRIPTIONA heat pump system according to the concepts of the present subject matter is generally indicated by the numbers 10, 10A in the drawings. Heat pump system 10, 10A includes a first heat exchanger 11, which is in communication with a conditioned space. As the term is used herein, unless otherwise noted, a “conditioned space” may be any region that is heated or cooled by the operation of the heat pump system 10, 10A. A conditioned space refers to the region to which or from which the heat pump system 10, 10A is adapted to pump heat. Without limitation, in some embodiments the conditioned space may be a room, building, vehicle interior, refrigerator interior, freezer interior, or other appliance, device, or structure that comprises a space to be temperature controlled. In some non-limiting embodiments, the first heat exchanger 11 may be referred to as an indoor heat exchanger or a conditioned space heat exchanger. Heat pump system 10, 10A also includes a second heat exchanger 12, which is in communication with an environment, which, without limitation, may be atmospheric air, or a geothermal region, a room, or some other region differing from the conditioned space, and may, in some non-limiting embodiments, be referred to as an outdoor heat exchanger or an environmental heat exchanger. When the conditioned space is to be cooled, the heat pump system 10, 10A operates to pump heat from the conditioned space to the environment. When the conditioned space is to be heated, the heat pump system 10, 10A operates to pump heat to the conditioned space from the environment. Heat pump system 10, 10A further includes a compressor 15. The heat pump system 10, 10A also includes a first expansion valve 21, a second expansion valve 22, a third expansion valve 23, and a four-way valve 24. The heat pump system 10, 10A also includes a thermal fluid, which may be any suitable liquid or gas used to transfer heat through the system. The thermal fluid may comprise a refrigerant chosen by one or ordinary skill in the art. Without limitation, a refrigerant may comprise a chlorofluorocarbon, a chlorofluoroolefin, a hydrochlorofluorocarbon, a hydrochlorofluoroolefin, a hydrofluorocarbon, a hydrofluoroolefin, a hydrochlorocarbon, a hydrochloroolefin, a hydrocarbon, a hydroolefin, a perfluorocarbon, a perfluoroolefin, a perchlorocarbon, a perchloroolefin, a halon, or combinations thereof. Without limitation, a refrigerant may comprise, R717, also known as ammonia, and having the formula NH3; R744, also known as carbon dioxide, and having the formula CO2; R12, also known as dichlorodifluoromethane, and having the formula CCl2F2; DME, also known as dimethyl ether, and having the formula CH3OCH3; R-124, also known as 1-Chloro-1,2,2,2-tetrafluoroethane, and having the formula C2HClF4; Freon 142b, also known as 1-Chloro-1,1-difluoroethane, and having the formula CH3CClF2; R-134a, also known as 1,1,1,2-Tetrafluoroethane, and having the formula CH2FCF3; HFO-1234yf, also known as 2,3,3,3-Tetrafluoropropene, and having the formula CH2═CFCF3; R-22 also known as chlorodifluoromethane, and having the formula CHClF2; R-410A, a mixture of difluoromethane, CH2F2, and pentafluoroethane, CHF2CF3; propane, having the formula C3H8; or combinations thereof. There are many other acceptable refrigerants which may be used. The present subject matter is not limited by refrigerant type.
Thermal fluid may comprise a liquid that changes phases as it undergoes compression or expansion in the system including, but not limited to, refrigerants such as R-134a and the like.
Compressor 15 includes a compressor discharge 16 and a compressor suction 17. The compressor discharge 16 is in communication with the four-way valve 24. The four-way valve 24, when in cooling mode (shown in
As the thermal fluid flows through the second heat exchanger 12, heat is released to the environment such that the thermal fluid exiting second heat exchanger 12 has less thermal energy; that is, is cooler. The cooled thermal fluid exiting the second heat exchanger 12 is further cooled as it flows through third expansion valve 23 and enters first heat exchanger 11. First heat exchanger 11 is, thus, used to cool the conditioned space S such as, without limitation, by cooling air provided to the conditioned space S. To facilitate this operation, in some non-limiting embodiments, a first fan 41 may be provided to direct air over the first heat exchanger 11 and into the conditioned space S. Ducting or vents may be provided to route air passing over first heat exchanger 11 to the conditioned space S in a devised manner. A second fan 42, likewise, may be provided to direct air over the second heat exchanger 12 to facilitate heat transfer from the second heat exchanger 12 to the environment. The thermal fluid exits first heat exchanger 11 at a second port 34. The second port 34 is in fluid communication with second valve 22 and four-way valve 24. As previously mentioned, in cooling mode, second valve 22 is closed such that the thermal fluid exiting first heat exchanger 11 is directed by four-way valve 24 to the compressor suction 17.
With reference to
In some embodiments, a heat pump system 10, 10A may comprise a heat accumulator 50, 150 in thermal communication with the compressor 15. A first non-limiting embodiment of a heat accumulator 50 is shown in
In the non-limiting embodiment shown in
As shown in
As shown, passage 55 may be located within only a portion of heat accumulator 50. For example, passage 55 may be located generally in the portion of accumulator 50 in closest contact with compressor 15. In the example shown, passage 55 generally resides in the concave portion 54 of accumulator 50 with an inlet 57 located near one end of the semi-circular portion 54 and an exit 58 at the opposite end of semi-circular portion 54. In this example, passage 55 traces a somewhat semi-circular path and generally conforms to the shape of surface 52. In other embodiments, passage 55 may be located fully within heat accumulator 50.
In the non-limiting embodiment shown in
As shown in
The passage 155 forms part of a heat transfer loop between compressor 15 and the heat accumulator 150. The flow of thermal fluid through the passage 155 may be driven by a pump 173. Passage 155 may extend throughout body 153 and may take a straight route through body 153 or include a non-straight path to increase the surface area of passage 155 within accumulator 150. For example, to form a non-straight path, passage 155 may include a number of turns that route the thermal fluid back and forth across the length and/or width of the heat accumulator body 153 such that passage 155 is a coil or otherwise convoluted.
With reference to the embodiment shown
With continued reference to the non-limiting embodiment shown
With reference to the embodiment shown
With reference to the non-limiting embodiment shown
It will be appreciated that, when using a thermal fluid that undergoes a phase change, thermal fluid exiting second heat exchanger 12 may be in the form of a low temperature mist and thermal fluid exiting heat accumulator 50 will be an over-heated thermal fluid gas such that when the two flows combine the low temperature mist is heated to a gas state avoiding any liquid pressure within the compressor suction 17.
In the example shown, the conduits, junctions, and valves are shown schematically and any suitable conduit junction, or valve may be used in accordance with the description above. Optionally, to segregate the heat accumulator passage 55, 159 during heating and cooling operations, an accumulator valve may be provided at the heat accumulator conduit upstream of the junction 60 where the heat accumulator outlet merges with the conduit extending from first port 31 of second heat exchanger 12.
The present invention may be embodied in other forms without departing from the spirit and the essential attributes thereof, and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.
Claims
1. A heat pump system for a conditioned space comprising:
- a first thermal fluid circuit adapted to selectably operate to circulate a thermal fluid therein, the first thermal fluid circuit comprising a compressor, a first heat exchanger, and a passage of a heat accumulator, wherein the heat accumulator a) comprises a solid surface in contact with the compressor, or b) is in thermal communication with the compressor through a heat transfer conduit; and
- a second thermal fluid circuit adapted to selectably operate to circulate the thermal fluid therein, the second thermal fluid circuit bypassing the first heat exchanger and the passage of the heat accumulator, and comprising the compressor, and a second heat exchanger.
2. The heat pump system of claim 1, wherein the thermal fluid is a refrigerant.
3. The heat pump system of claim 2, wherein the passage of the heat accumulator is at least partially within the heat accumulator.
4. The heat pump system of claim 3, wherein the first thermal fluid circuit and the second thermal fluid circuit are conjoined to form a continuous system.
5. The heat pump system of claim 3, wherein the system is adapted to be operable to flow the thermal fluid through the first thermal fluid circuit and to simultaneously flow the thermal fluid through the second thermal fluid circuit.
6. The heat pump system of claim 4, wherein the system is adapted to be operable to flow the thermal fluid through the first thermal fluid circuit and to simultaneously flow the thermal fluid through the second thermal fluid circuit.
7. The heat pump system of claim 1, wherein the heat accumulator comprises the solid surface, the solid surface being in direct thermal contact with the compressor.
8. The heat pump system of claim 7, wherein the heat accumulator is adapted to transfer heat from the compressor primarily by conduction.
9. The heat pump system of claim 6, wherein the heat accumulator is in thermal communication with the compressor through the heat transfer conduit.
10. The heat pump system of claim 9, wherein the heat transfer conduit comprises a solid surface in direct thermal contact with the compressor.
11. A method of defrosting a part of a heat pump system for a conditioned space comprising:
- providing a heat pump system for a conditioned space comprising, a first thermal fluid circuit adapted to selectably operate to circulate a thermal fluid therein, the first thermal fluid circuit comprising a compressor, a first heat exchanger, and a passage of a heat accumulator, wherein the heat accumulator a) comprises a solid surface in contact with the compressor, or b) is in thermal communication with the compressor through a heat transfer conduit; and a second thermal fluid circuit adapted to selectably operate to circulate the thermal fluid therein, the second thermal fluid circuit bypassing the first heat exchanger and the passage of the heat accumulator, and comprising the compressor, and a second heat exchanger;
- operating the system, to circulate the thermal fluid in first thermal fluid circuit, and to circulate the thermal fluid in the second thermal fluid circuit.
12. The method of defrosting a part of a heat pump system for a conditioned space of claim 11, wherein the thermal fluid is a refrigerant.
13. The method of defrosting a part of a heat pump system for a conditioned space of claim 12, wherein the passage of the heat accumulator is at least partially within the heat accumulator.
14. The method of defrosting a part of a heat pump system for a conditioned space of claim 13, wherein the first thermal fluid circuit and the second thermal fluid circuit are conjoined to form a continuous system.
15. The method of defrosting a part of a heat pump system for a conditioned space of claim 13, wherein the system is adapted to be operable to flow the thermal fluid through the first thermal fluid circuit and to simultaneously flow the thermal fluid through the second thermal fluid circuit.
16. The method of defrosting a part of a heat pump system for a conditioned space of claim 14, wherein the system is adapted to be operable to flow the thermal fluid through the first thermal fluid circuit and to simultaneously flow the thermal fluid through the second thermal fluid circuit.
17. The method of defrosting a part of a heat pump system for a conditioned space of claim 16, wherein the heat accumulator is adapted to transfer heat from the compressor primarily by conduction.
18. The method of defrosting a part of a heat pump system for a conditioned space of claim 16, wherein the heat accumulator is in thermal communication with the compressor through the heat transfer conduit.
19. The method of defrosting a part of a heat pump system for a conditioned space of claim 18, wherein the heat transfer conduit comprises a solid surface in direct thermal contact with the compressor.
20. The heat pump system of claim 1:
- wherein the thermal fluid is a refrigerant;
- wherein the heat accumulator a) comprises the solid surface, the solid surface being in direct thermal contact with the compressor, and is adapted to transfer heat from the compressor primarily by conduction, or b) is in thermal communication with the compressor through the heat transfer conduit, and the heat transfer conduit comprises a solid surface in direct thermal contact with the compressor;
- wherein the passage is at least partially within the heat accumulator;
- wherein the first thermal fluid circuit and the second thermal fluid circuit are conjoined to form a continuous system; and
- wherein the system is adapted to be operable to flow the thermal fluid through the first thermal fluid circuit and to simultaneously flow the thermal fluid through the second thermal fluid circuit.
Type: Application
Filed: Jul 17, 2014
Publication Date: Jul 27, 2017
Inventor: Wei LIU (Hangzhou)
Application Number: 15/325,981