| WO/2012/041225 | AIR CONDITIONING WATER HEATER |
| JP2002372318 | HEAT PUMP DEVICE |
| WO/2001/020232 | IMPROVED HEAT PUMP WATER HEATER AND METHOD OF MAKING THE SAME |
ZHANG, Junjie (336 Yaoxin Avenue, NETZNanjing, Jiangsu Province 8, 210038, CN)
YAN, Song (336 Yaoxin Avenue, NETDZNanjing, Jiangsu Province 8, 210038, CN)
ZHANG, Junjie (336 Yaoxin Avenue, NETZNanjing, Jiangsu Province 8, 210038, CN)
| CLAIMS What is claimed is: 1. A heat pump water heater, comprising: a compressor; a water storage tank having an exterior surface and an interior volume; a heat exchanger including an external section and an internal section, the heat exchanger secured to the water storage tank such that the exterior section is in contact with the exterior surface in a heat exchange relationship and the internal section is positioned within the interior volume and is configured to exchange heat with water in the water storage tank; an expansion device; and an evaporator; wherein the compressor, the heat exchanger, the expansion device, and the evaporator are connected in series; and wherein the external section is configured to receive refrigerant from the compressor, the internal section is configured to supply refrigerant to the expansion device, and the external section is connected in series with the internal section. 2. The heat pump water heater of claim 1, wherein sensible heat exchange occurs in the external section and condensing heat exchange occurs in the internal section. 3. The heat pump water heater of claim 2, wherein the internal section includes an inner tube, an outer tube, and a drainage slot defined between the inner tube and the outer tube, the drainage slot leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slot. 4. The heat pump water heater of claim 3, wherein a plurality of drainage slots are defined between the inner tube and the outer tube, the drainage slots leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slots. 5. The heat pump water heater of claim 4, wherein the external section is a spiral and refrigerant flows from the top down through the external section. 6. The heat pump water heater of claim 5, wherein the internal section is a spiral and refrigerant flows from the bottom up through the internal section. 7. The heat pump water heater of claim 1, wherein the refrigerant is in a gaseous state in the external section and the refrigerant is in a condensing gas-liquid state in the internal section. 8. The heat pump water heater of claim 7, wherein the internal section includes an inner tube, an outer tube, and a drainage slot defined between the inner tube and the outer tube, the drainage slot leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slot. 9. The heat pump water heater of claim 1, wherein the internal section includes an inner tube, an outer tube, and a drainage slot defined between the inner tube and the outer tube, the drainage slot leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slot. 10. The heat pump water heater of claim 9, wherein a plurality of drainage slots are defined between the inner tube and the outer tube, the drainage slots leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slots. 11. The heat pump water heater of claim 9, wherein the external section is a spiral and refrigerant flows from the top down through the external section. 12. The heat pump water heater of claim 11, wherein the internal section is a spiral and refrigerant flows from the bottom up through the internal section. 13. The heat pump water heater of claim 1, wherein the external section is a spiral and refrigerant flows from the top down through the external section. 14. The heat pump water heater of claim 1, wherein the internal section is a spiral and refrigerant flows from the bottom up through the internal section. 15. A combination heat exchanger and water storage tank for use with a heat pump water heater, comprising: a water storage tank having an exterior surface and an interior volume; and a heat exchanger including an external section and an internal section, the heat exchanger secured to the water storage tank such that the exterior section is in contact with the exterior surface in a heat exchange relationship and the internal section is positioned within the interior volume and is configured to exchange heat with water in the water storage tank; wherein the external section is configured to receive refrigerant, the internal section is configured to discharge refrigerant, and the external section is connected in series with the internal section. 16. The combination heat exchanger and water storage tank of claim 15, wherein the external section is configured such that sensible heat exchange occurs in the external section and the internal section is configured such that condensing heat exchange occurs in the internal section. 17. The combination heat exchanger and water storage tank of claim 15, wherein the external section is configured such that the refrigerant is in a gaseous state in the external section and the internal section is configured such that the refrigerant is in a condensing gas-liquid state in the internal section. 18. The combination heat exchanger and water storage tank of claim 15, wherein the internal section includes an inner tube, an outer tube, and a drainage slot defined between the inner tube and the outer tube, the drainage slot leading to outside of the water storage tank such that any refrigerant that may leak from the inner tube is directed outside of the water storage tank through the drainage slot. 19. The combination heat exchanger and water storage tank of claim 15, wherein the external section is a spiral and is configured such that refrigerant flows from the top down through the external section. 20. The combination heat exchanger of claim 19, wherein the internal section is a spiral and is configured such that refrigerant flows from the bottom up through the internal section. |
BACKGROUND
[0001] The present invention relates to heat pump water heaters. SUMMARY
[0002] Heat pump water heaters have good energy saving effect and thus have spread rapidly. As investigated by the applicant, there are two kinds of assembly modes between the heat exchange tube and the water storage tank of existing heat pump water heaters: one kind is external heat exchange tube, namely the heat exchange tube is wound around the outside wall of the water storage tank and exchange heat with the water in the water storage tank indirectly; and the other kind is built-in heat exchange tube, namely the heat exchange tube is installed in the water storage tank and exchange heat with the water in the water storage tank directly. The shortcoming of the former is the low heat exchange efficiency while the shortcoming of the later is that scaling is apt to form on the tube wall due to high original temperature of the heat exchange medium or refrigerant, which will reduce the heat exchange efficiency. Besides, it is possible after a time of service for the heat-exchange medium in the heat exchange tube to leak, which will pollute the water in the water storage tank.
[0003] In one embodiment, the invention provides a storage heat pump water heater with a composite heat exchanger which has high heat exchange efficiency and reduced scaling.
[0004] In another embodiment the invention provides a storage heat pump water heater with a composite heat exchanger which may effectively avoid heat-exchange medium or refrigerant leakage.
[0005] To achieve the above goals, the storage heat pump water heater with composite heat exchange of this utility model includes the water storage tank with water inlet and water outlet and the condenser heat exchange tube of the heat pump system and it is characterized in that: the said heat exchange tube is composed of the external section and the internal section; the said external section is closely attached to the outside wall of the said water storage tank; the said internal section is installed in the said water storage tank and the said external section is connected with the said internal section in series.
[0006] The further improvement of this utility model is that the length of the said external section and the internal section is calculated to make the heat exchange medium in the external section to be gaseous and form sensible heat exchange under ideal conditions (generally speaking, it is ok if only most heat exchange medium is gaseous) and to be gas-liquid in the internal section and form condensation heat exchange at work.
[0007] In service, the heat exchange medium of the heat pump system enters the external section firstly and exchanges heat with the water in the water storage tank indirectly through the water storage tank's wall, and then enters the internal section after its temperature is lowered and exchange heat with the water in the water storage tank directly through the tube wall. Because the high temperature and high pressure gaseous heat exchange medium produced by the compressor has accomplished sensible heat exchange outside the water storage tank before enters the water storage tank to conduct condensation heat exchange, the heat exchange temperature of the tube wall with water in the water storage tank is lowered, therefore scaling is remarkably reduced with rather high heat exchange efficiency.
[0008] To achieve the further goal of this utility model, the said internal section has inter- attached inner and outer tubes and there is at least one drainage slot between the said inner and outer tubes leading to outside of the water storage tank. Therefore, once the inner tube of the internal section leaks, the heat exchange medium will be guided out and will not pollute the water in the water storage tank.
[0009] In one embodiment, the invention provides a heat pump water heater including a compressor, a water storage tank, a heat exchanger, an expansion device, and an evaporator. The water storage tank has an exterior surface and an interior volume. The heat exchanger includes an external section and an internal section. The heat exchanger is secured to the water storage tank such that the exterior section is in contact with the exterior surface in a heat exchange relationship and the internal section is positioned within the interior volume and is configured to exchange heat with water in the water storage tank. The compressor, the heat exchanger, the expansion device, and the evaporator are connected in series. The external section is configured to receive refrigerant from the compressor, the internal section is configured to supply refrigerant to the expansion device, and the external section is connected in series with the internal section.
[0010] In another embodiment, the invention provides a combination heat exchanger and water storage tank for use with a heat pump water heater. The water storage tank has an exterior surface and an interior volume. The heat exchanger includes an external section and an internal section. The heat exchanger is secured to the water storage tank such that the exterior section is in contact with the exterior surface in a heat exchange relationship and the internal section is positioned within the interior volume and is configured to exchange heat with water in the water storage tank. The external section is configured to receive refrigerant, the internal section is configured to discharge refrigerant, and the external section is connected in series with the internal section.
[0011] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 is a perspective view of a combination heat exchanger and water storage tank for use with a heat pump water heater.
[0013] Figure 2 is a detailed sectional view of area 2-2 of the combination heat exchanger and water storage tank of Figure 1.
[0014] Figure 3 is a sectional view of the internal section of the heat exchange tube along line 3-3 of Figure 2.
[0015] Figure 4 is a schematic view of a heat pump water heater. DETAILED DESCRIPTION
[0016] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
[0017] Figure 4 illustrates a heat pump water heater 100 that includes a compressor 105, a heat exchanger or condenser 110, an expansion device 115, and an evaporator 120 connected in series. The heat pump water heater 100 functions according to a vapor-compression heat pump cycle.
[0018] The storage heat pump water heater 100 with a composite heat exchanger 110 is shown in Figure 1. The heat exchanger 110 includes a water storage tank 125 and a heat exchange tube 130. The water storage tank 125 includes a water inlet 135 and a water outlet (not shown). The heat exchange tube 130 includes an external section 140 and an internal section 145. The external section 140 is connected to the compressor 105 by a refrigerant inlet 150 and the internal section 145 is connected to the expansion device 115 by a refrigerant outlet 155. The external section 140 starts at the refrigerant inlet 150 and is wound in a spiral around the lower part of the exterior surface 160 of the water storage tank 125 in a downward direction. The internal section 145 is installed in the lower part of an internal volume 165 of the water storage tank 125 and is wound in a spiral from the bottom up with an end connected to the refrigerant outlet 155. The external section 140 is connected with the internal section 145 in series and the length ratio of the external section 140 to the internal section 145 is calculated to make the refrigerant or heat exchange medium to be gaseous in the external section 140 and gas-liquid in the internal section 145 so as to cause sensible heat exchange to occur in the external section 140 and condensing heat exchange to occur in the internal section 145. Preferably, the length ratio of the external section 140 to the internal section 145 is 1:6 and may range from 1:5 to 1:7.
[0019] As shown as Figures 2 and 3, the internal section 145 includes an inner tube 170 and an outer tube 175. Four grooves are formed in the outside surface of the inner tube 170 along the axial direction of the inner tube 170 to create four drainage slots 180 between the inner tube 170 and the outer tube 175. The drainage slots 180 lead to outside of the water storage tank 125. The outside surface of the outer tube 175 is covered with an enamel layer 185 and is welded to the water storage tank 125 at a welded joint 190. The expanded end of the inner tube 170 is plugged into the end of the external section 140 and connected with the external section 140 by the brazing weld 195.
[0020] Therefore, if the inner tube 170 of the internal section 145 leaks, the refrigerant or heat exchange medium 200 will be guided out of the water storage tank 125 and will not pollute the water in the water storage tank 125. In service, the high temperature and high pressure gaseous refrigerant is passed through the refrigerant inlet 150, passes through the external or sensible heat exchange section 140, and then enters the internal or condensing heat exchange section 145 and condenses. Finally, liquid refrigerant returns to the expansion device 115 of the heat pump water heater 100 through the refrigerant outlet 155.
[0021] Because the high temperature and high pressure gaseous refrigerant produced by the compressor 105 has completed sensible heat exchange in the external section 140 outside the water storage tank 125 before entering the internal section 145 in the water storage tank 125 to carry out condensing heat exchange, the heat exchange temperature of the internal section 145 that is in direct contact with the water is lowered and scaling on the internal section 145 is remarkably reduced.
[0022] Experiments prove that the heat pump water heater 100 improves upon the existing heat pump water heaters, as described above, in at least the following ways: the scaling on the heat exchanger 110 in the water storage tank 125 is remarkably reduced, the heat exchange efficiency is increased, and possible pollution or contamination of refrigerant leakage from the heat exchange tube 130 to the water in the water storage tank 125 is avoided. The performance of the heat pump water heater 100 is good, safe and reliable.
[0023] Thus, the invention provides, among other things, a heat pump water heater and a combination heat exchanger and water storage tank for use with a heat pump water heater.
Various features and advantages of the invention are set forth in the following claims.
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