JP2005133999A - Heat pump type hot-water supplier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type hot-water supplier having smaller size, lower cost and higher efficiency as a whole at the same time by improving space saving property, cost and heat exchanging performance of a water-refrigerant heat exchanger at the same time. <P>SOLUTION: The heat pump water heater 7 with the heat exchanger 1 comprises a water heat transfer pipe 3 in which water is distributed and one or more refrigerant heat transfer pipes 5 for each water heat transfer pipe, in which refrigerant 4 is distributed, both of which are spirally wound into almost cylindrical whole shapes and integrally put in contact with each other. The water heat transfer pipe is spirally wound into a almost cylindrical shape in close contact or with almost no gap in the axial direction. The refrigerant heat transfer pipe is spirally wound and arranged on the outer or inner periphery or on both of them of the cylindrical shape of the water heat transfer pipe. It is brazed or soldered on at least one cross section to the water heat transfer pipe all over the length of the heat transfer pipe so that the water and the refrigerant can flow inside the water heat transfer pipe and the refrigerant heat transfer pipe in the opposite directions to each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump type water heater provided with a water-to-refrigerant heat exchanger such as a hot water supply heat exchanger.

  Conventionally, in consideration of space saving in a heat pump type hot water heater, the entire shape is spirally wound around a cylinder or a square pole, and is arranged on the outer periphery of the hot water storage tank or the inner periphery of the water heater case. There are water-to-refrigerant heat exchangers (hereinafter referred to as water-refrigerant heat exchangers) that can be arranged in a grid or nested manner. As a heat pump type water heater provided with such a water refrigerant heat exchanger, there is one in which flat water heat transfer tubes and refrigerant heat transfer tubes are arranged side by side so as to be alternately contacted in the vertical direction and spirally wound (for example, Patent Document 1). reference). In such a water-refrigerant heat exchanger, the water heat transfer tube and the refrigerant heat transfer tube are originally low-cost circular cross-section piping, so even if processing is included, originally low-cost circular cross-section piping is sufficient, Although the water heat transfer tube and the refrigerant heat transfer tube are in contact with each other in a flat plane, the contact heat resistance of this part is larger than that of joining such as brazing because it remains in mechanical contact. Even if the refrigerant is flowed in the opposite direction (opposite flow), there is a problem that the performance of the heat exchanger deteriorates. Further, since the water heat transfer tubes and the refrigerant heat transfer tubes are alternately arranged in the vertical direction and spirally wound, the overall height of the cylindrical shape or the like increases, so that the space saving effect is hardly obtained. Also, when the refrigerant is carbon dioxide, the working pressure is larger than the chlorofluorocarbon refrigerant and the pressure loss in the pipe is small, so the refrigerant heat transfer tube suitable for the water refrigerant heat exchanger is considerably smaller in diameter than the water heat transfer tube. Therefore, it is considered that problems such as molding and contact thermal resistance increase in the structure in which the water heat transfer tubes and the refrigerant heat transfer tubes are alternately arranged in the vertical direction and spirally wound as in this conventional example. As a result, the heat pump type hot water heater leads to the problem that the entire device is enlarged and the efficiency is lowered.

  In addition, as a heat pump water heater equipped with a water-refrigerant heat exchanger capable of spirally winding other overall shapes into a cylinder or the like, both flat water heat transfer tubes and refrigerant transfer pipes are used, particularly in order to use high-pressure carbon dioxide as the refrigerant. Some heat pipes are provided with a water refrigerant heat exchanger in which a plurality of small channels are formed in the cross section from the point of pressure resistance (for example, for example, a refrigerant heat transfer pipe is spirally wound so that the heat pipes are alternately contacted in the vertical direction (for example, Patent Document 2). In such a water-refrigerant heat exchanger, the water heat transfer tubes and the refrigerant heat transfer tubes are arranged alternately in the vertical direction and spirally wound. However, since both heat transfer tubes are flattened, As a result, the space-saving performance is not impaired. However, since the refrigerant heat transfer tube is a custom-made product with a complicated cross-sectional shape, not only is it costly, but the water heat transfer tube and the refrigerant heat transfer tube are in flat contact but remain in mechanical contact, so brazing, etc. There is a problem that the contact heat resistance of this portion becomes larger than that of bonding, and the performance of the heat exchanger is lowered even if water and refrigerant are flowed in opposite directions. As a result, even for a heat pump type hot water heater, it leads to problems of cost increase and efficiency reduction of the entire device.

  In addition, as a heat pump type water heater equipped with a water refrigerant heat exchanger that can be spirally wound around a cylinder or the like in other overall shapes, a plurality of hollow portions in which water heat transfer tubes are connected in the length direction of the tube in an elliptical cross section. In addition, as a structure in which a refrigerant heat transfer tube having a substantially circular cross section is fixed by crimping in the hollow portion, there is one provided with a water refrigerant heat exchanger in which they are spirally wound without leaving a gap (see, for example, Patent Document 3). ). In such a water-refrigerant heat exchanger, the water heat transfer tube and the refrigerant heat transfer tube are arranged so as to be spirally wound side by side in the vertical direction, but since the refrigerant heat transfer tube is arranged in the cross section of the flat water heat transfer tube, The height is not increased and the space saving performance is not impaired. However, although the water heat transfer tube and the refrigerant heat transfer tube are originally low-cost pipes with a circular cross section, the water heat transfer tube is molded to have a hollow portion, and then the refrigerant heat transfer tube is pressure-bonded and fixed there. Cost because it is necessary. In addition, although the refrigerant heat transfer tube is crimped and fixed in the recess of the water heat transfer tube, it remains in mechanical contact, and deformation due to the entire spiral winding process has an adverse effect on the contact state, so joining such as brazing Compared with the above, the contact thermal resistance of this portion becomes large, and there is a problem that the performance of the heat exchanger is deteriorated even if water and the refrigerant are caused to flow in opposite directions. As a result, even for a heat pump type hot water heater, it leads to problems of cost increase and efficiency reduction of the entire device.

  In addition, as a water-refrigerant heat exchanger with a structure in which the water heat transfer tube and the refrigerant heat transfer tube are made into a low-cost pipe with a circular cross section and integrated by joining such as brazing, the use of carbon dioxide as a refrigerant is assumed. There is a structure in which a plurality of refrigerant heat transfer tubes having a substantially circular cross section are joined and integrated above and below the water heat transfer tube (see, for example, Patent Document 4). In such a water-refrigerant heat exchanger, the water heat transfer tube and the refrigerant heat transfer tube are originally low-cost pipes having a circular cross section, and their bending and joining are easy processing, so that an increase in cost can be suppressed. In addition, since the water heat transfer tube and the refrigerant heat transfer tube are integrated by bonding, the contact heat resistance between them can be kept small as compared with the mechanical contact as in the two conventional examples described above. However, in such a structure of the water refrigerant heat exchanger, the water heat transfer tube can be wound only in the lateral direction without the refrigerant heat transfer tube, so the overall diameter of the water refrigerant heat exchanger is increased in the horizontal direction. Although a flat spiral shape is possible, it cannot be applied to the overall shape of a cylinder or the like in consideration of space saving. In addition, a processing procedure is assumed in which a plurality of refrigerant heat transfer tubes are joined to the top and bottom of the water heat transfer tube and then the whole is made into a flat spiral shape. However, if the winding process is performed after joining the two, the joint will be cracked and peeled off. Etc. may occur. For this reason, the water heat transfer tube and the refrigerant heat transfer tube are actually processed into a flat spiral shape and then joined, which complicates the processing involved in joining and increases the cost for processing. As a result, the heat pump type hot water heater leads to the problem of cost increase and size increase of the entire device.

Japanese Patent Laying-Open No. 2003-14383 (page 7, FIG. 6) Japanese Patent Laid-Open No. 2002-107069 (Page 4, FIGS. 1 and 2) Japanese Patent Laying-Open No. 2003-14383 (page 6, FIG. 2, FIG. 3) Japanese Patent Laying-Open No. 2003-156291 (page 8, FIGS. 1 and 4)

  As described above, in the conventional heat pump type water heater, the water-refrigerant heat exchanger has an overall shape such as a cylinder excellent in space saving, is low in cost in terms of materials and processing, and has a water heat transfer tube. There is nothing that can simultaneously achieve the characteristics that the contact heat resistance of the refrigerant heat transfer tube is small and the heat exchange performance is excellent, so even for a heat pump type hot water heater, it solves all the problems of increase in cost, size, and efficiency of the entire device I couldn't.

  The object of the present invention is to reduce the contact heat resistance between the water heat transfer tube and the refrigerant heat transfer tube at a low cost from the viewpoint of materials and processing, etc., while making the water refrigerant heat exchanger into an overall shape such as a cylinder excellent in space saving. Improved heat pump type that can simultaneously achieve downsizing, cost reduction, and high efficiency of the entire equipment as a heat pump type hot water heater. The purpose is to provide a water heater.

  In order to achieve the above object, the heat pump type hot water heater according to the first aspect of the present invention has a water heat transfer pipe through which water flows and one or a plurality of refrigerants flow through one water heat transfer pipe. The refrigerant heat transfer tube has a structure in which the refrigerant heat transfer tubes are in contact with each other in an overall shape such as a substantially cylindrical shape that is spirally wound together, and the water heat transfer tubes are closely wound in the axial direction of the cylinder or the like and spirally wound with almost no gap. The refrigerant heat transfer tube is spirally wound around the outer periphery or the inner periphery of the water heat transfer tube or the like, or both, and is at least one in cross section with the water heat transfer tube. A heat exchanger is provided in which at least a portion is joined by brazing or soldering over almost the entire length of the heat transfer tube, and water and refrigerant are allowed to flow in opposite directions inside the water heat transfer tube and the refrigerant heat transfer tube. It is characterized by that.

  Moreover, the heat pump type water heater according to the second aspect of the present invention is the heat pump type water heater according to claim 1, wherein a part of the refrigerant heat transfer tube of the heat exchanger is adjacent to the water heat transfer tube. The outer periphery and / or the inner periphery of the intermediate position is spirally wound at the same pitch as the water heat transfer tube, and a part of the refrigerant heat transfer tube extends over almost the entire length of the two heat transfer tubes facing each other. It is characterized by being joined by brazing or soldering.

  Moreover, the heat pump type hot water heater according to the third aspect of the present invention is the heat pump type hot water heater according to claim 1 or 2, wherein a part of the refrigerant heat transfer tube of the heat exchanger is the water heat transfer tube. The outer periphery or the inner periphery or both are spirally wound at a pitch changed in the length direction of the heat transfer tube, and the helical winding pitch of the refrigerant heat transfer tube is the refrigerant transfer in the typical operation state of the heat pump water heater. It is characterized in that it is determined based on the heat exchange performance inside the heat pipe or the temperature difference between water and the refrigerant.

  According to a fourth aspect of the present invention, there is provided a heat pump type water heater according to any one of the first to third aspects, wherein the refrigerant is carbon dioxide.

  Moreover, the heat pump type water heater according to the fifth aspect of the present invention is the compressor according to any one of claims 1 to 4, wherein the compressor compresses the refrigerant and heats the water by exchanging heat between the refrigerant and the water from the compressor. A heat exchanger, an expansion valve for expanding the refrigerant from the heat exchanger, an evaporator for exchanging heat between the refrigerant from the expansion valve and the outside air to evaporate the refrigerant, and heated by the refrigerant in the heat exchanger It is characterized by comprising a hot water storage tank for storing water, piping and control equipment for circulating water and refrigerant in necessary paths.

  In the heat pump type hot water heater according to the first aspect of the present invention described above, (1) the water-refrigerant heat exchanger has an overall shape of a cylinder or the like, and therefore is disposed on the outer periphery of the hot water storage tank or the inner periphery of the water heater case. It can be divided into a plurality of grids, nested, etc., and is excellent in space saving. (2) The water / refrigerant heat exchanger has originally a low-cost circular cross-section pipe for the water heat transfer pipe and the refrigerant heat transfer pipe. While using the water heat transfer tube spirally in advance, the refrigerant heat transfer tube is spirally wound around the outer periphery and the inner periphery, and processing is easy, such as joining them, thereby reducing the cost as a whole. (3) Since the water refrigerant heat exchanger integrates the water heat transfer pipe and the refrigerant heat transfer pipe by joining, the contact heat resistance is smaller than that of the mechanical contact like the conventional water refrigerant heat exchanger. In addition to flowing as a counter flow with good heat exchange efficiency , There is an effect that can increase the overall heat exchange performance. In the heat pump type water heater provided with such a water-refrigerant heat exchanger, the size of the entire device can be reduced by the aforementioned (1), and the cost of the entire device can be reduced by the aforementioned (2). As a result, high efficiency of the entire device can be achieved at the same time.

  In the heat pump type water heater according to the second aspect of the present invention, a part of the refrigerant heat transfer tube is located in the middle of the two water heat transfer tubes facing each other in the water / refrigerant heat exchanger, Since it is joined by brazing or soldering over almost the entire length, the heat of the refrigerant heat transfer tube is transmitted to the two water heat transfer tubes, so that the contact thermal resistance can be made smaller than when only one water heat transfer tube is transferred, Water and refrigerant are allowed to flow in opposite directions, which has the effect of improving the heat exchange performance of the water refrigerant heat exchanger. Also in this case, the effects of the water-refrigerant heat exchanger can be obtained at the same time as (1) to (3) as in the first claim. Therefore, the effect on the heat pump type hot water heater is also the first claim. In the same way, downsizing, cost reduction and high efficiency of the entire device can be obtained at the same time.

  In the heat pump type water heater according to the third aspect of the present invention, a part of the refrigerant heat transfer tube in the water / refrigerant heat exchanger is arranged on the outer periphery or the inner periphery or both of the water heat transfer tube. Heat exchange performance inside the refrigerant heat transfer tube in various operating conditions (the refrigerant side heat transfer rate tends to improve near the critical temperature of the refrigerant) or the temperature difference between water and refrigerant (water refrigerant heat in typical operating conditions) The temperature difference tends to be large at the inlet / outlet of the exchanger), so that the heat exchange between water and refrigerant is appropriate over the entire length of the water / refrigerant heat exchanger, and the overall heat exchange performance can be improved. effective. Also in this case, the effects of the water-refrigerant heat exchanger can be obtained at the same time as (1) to (3) as in the first and second claims. Therefore, the effects on the heat pump hot water heater are also the first to second. As with the second claim, the entire device can be reduced in size, cost and efficiency.

  In the heat pump type hot water heater according to the fourth aspect of the present invention, since the refrigerant is carbon dioxide in the water-refrigerant heat exchanger, the hot water can be discharged at a higher temperature if operated under a higher pressure condition than before. Because there is an effective hot water supply. In this case as well, the effects on the water-refrigerant heat exchanger can be obtained at the same time as (1) to (3) as in the first to third claims. Therefore, the effect in the heat pump hot water heater is also the first to third. As in the third aspect, the entire device can be reduced in size, cost and efficiency.

  In the heat pump type water heater according to the fifth aspect of the present invention, the water-refrigerant heat exchanger is provided with the components of the heat pump type water heater necessary for effective hot water supply, and the water refrigerant heat exchanger is described in claims 1 to 4. Therefore, in this case as well, the effects on the water-refrigerant heat exchanger can be obtained at the same time as (1) to (3) as in the first to fourth claims. As in the first to fourth claims, the effect of the present invention can be obtained simultaneously with downsizing, cost reduction and high efficiency of the entire device.

  According to the present invention, in the heat pump type hot water heater, the water-refrigerant heat exchanger has an overall shape such as a cylinder and is excellent in space saving, and can be reduced in cost in terms of materials and processing, and is opposed to and in contact with the flow. Because of the heat transfer tube configuration with low heat resistance, it also has the effect of excellent heat exchange performance. As a result, the heat pump water heater can simultaneously achieve downsizing, cost reduction, and high efficiency of the entire equipment. Become.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are a longitudinal sectional view and a detailed sectional view of a water-refrigerant heat exchanger in a heat pump type hot water heater of one embodiment (first embodiment) of the present invention, and a schematic system diagram of a hot water supply system.

  The water-refrigerant heat exchanger 1 is spirally wound so that the water heat transfer tube 3 through which the water 2 flows has a substantially cylindrical shape so that there is almost no gap between the water heat-transfer tubes 3. Similarly, the flowing refrigerant heat transfer tube 5 is spirally wound so as to be disposed in a valley portion that is an intermediate position between the two water heat transfer tubes 3 facing each other, and a contact portion between the two water heat transfer tubes 3 is a heat transfer tube. Are joined by a joining material 6 such as solder or solder.

  Since such a water refrigerant heat exchanger 1 has a cylindrical shape as a whole, it can be installed on the outer periphery of the hot water storage tank and the like, and the refrigerant heat transfer tube 5 is disposed around the water heat transfer tube 3. The height of the entire cylindrical shape is suppressed rather than being alternately arranged one above the other, and the thickness of the spirally wound portion (difference between the innermost circumference and the outermost circumference) is also reduced to the refrigerant heat transfer tube 5 in the middle valley portion of the water heat transfer tube 3. Is not so large (as the carbon dioxide refrigerant having a thinner refrigerant heat transfer tube has a smaller thickness increase), it is excellent in space saving. In addition, a low-cost pipe with a circular cross section can be used for the water heat transfer tube 3 and the refrigerant heat transfer tube 5, and the heat exchanger tube 5 is wound around the water heat transfer tube 3 in advance and the refrigerant heat transfer tube 5 is arranged on the outer periphery. It can be arranged in a spiral manner (if the both ends are fixed by applying a tensile force, the refrigerant heat transfer tube 5 is brought into close contact with the intermediate valley portion of the water heat transfer tube 3), and an easy method such as joining them is possible. Therefore, the cost of the heat exchanger can be suppressed. Further, since the water heat transfer tube 6 and the refrigerant heat transfer tube 5 are integrated by joining with the joining material 6, the contact heat resistance is smaller than that of the mechanical contact as in the example of the conventional water refrigerant heat exchanger, and the refrigerant heat transfer tube. The contact heat resistance can be further reduced by joining the two water heat transfer tubes 3 opposed to each other and transferring heat from two locations on the tube cross section. In addition, since the water 2 in the water heat transfer tube 3 and the refrigerant 4 in the refrigerant heat transfer tube 5 are counterflows advantageous for heat exchange, the heat exchange performance of the water refrigerant heat exchanger 1 is also improved.

  In a typical system of the heat pump type hot water heater 7 provided with the water refrigerant heat exchanger 1 described above, the refrigerant 4 in the refrigerant circuit on the left side becomes low pressure / low temperature in the expansion valve 8, and heat exchange with the outside air is performed in the evaporator 9. Then, it evaporates and absorbs heat, becomes high pressure and high temperature in the compressor 10, enters the water / refrigerant heat exchanger 1 from two paths, dissipates heat to the water 2, merges in one path, and returns to the expansion valve 8. In the water circuit on the right side, during the hot water supply operation indicated by the arrow without parentheses, the water 2 is supplied from the lower right and branches through the check valve 11 and the pressure reducing valve 12, and one of them passes through the check valve 13. The refrigerant enters the water refrigerant heat exchanger 1 through two paths, receives heat from the refrigerant, is heated, and reaches the mixing valve 14. On the other hand, the water 2 branched upward by the pressure reducing valve 12 enters below the hot water storage tank 15, and the same amount of hot water 2 (hot water) flows from above the hot water storage tank 15 to the mixing valve 14. The mixing valve 14 controls and mixes the flow rate of the water 2 (hot water) from the two paths in accordance with the requested amount of hot water and the temperature of the hot water, and discharges the hot water through the valve 16. Depending on the temperature of the water 2 (hot water) from the water-refrigerant heat exchanger 1 and the hot water storage tank 15 and the required hot water temperature, hot water may be discharged from only one side. Further, a valve 17 is provided between the pipe from the water supply and the pipe from the tapping water. Further, during the hot water storage operation indicated by the arrows with parentheses, the water 2 circulates between the water refrigerant heat exchanger 1 and the hot water storage tank 15, and the water 2 (hot water) in the hot water storage tank 15 is heated to a high temperature. The above system is a typical example, and even with the same function, other configurations are possible for effective hot water supply, and it can be used for various functions such as hot water supply to the bath, additional cooking, floor heating, and bathroom drying. The actual system configuration is not limited to this, as other additional components / routes can be added to cope with it. The system of the heat pump type hot water heater 7 having the above-described configuration enables effective hot water supply, and the water refrigerant heat exchanger 1 has the above-described effects. Since the refrigerant heat exchanger 1 has a space-saving structure, the overall size of the equipment is reduced, and the water refrigerant heat exchanger 1 is low in terms of materials, processing, etc., so that the overall cost of the equipment is reduced. Since the water-refrigerant heat exchanger 1 has high heat exchange performance, high efficiency of the system, in other words, the entire device can be achieved at the same time.

  FIG. 3 is a longitudinal sectional view of a water-refrigerant heat exchanger in a heat pump type water heater according to another embodiment (second embodiment) of the present invention.

  In the water-refrigerant heat exchanger 1 of this embodiment, two refrigerant heat transfer tubes 5 are provided for one of the water heat transfer tubes 3 on the outer periphery of the water heat transfer tube 3 spirally wound so as to have a substantially cylindrical shape as a whole. It arrange | positions and both contact parts are joined over the substantially full length of the heat exchanger tube. One of the two refrigerant heat transfer tubes 5 with respect to one of the water heat transfer tubes 3 has two opposite water like the refrigerant heat transfer tubes 5 of the water refrigerant heat exchanger 1 of the first embodiment described above. Since the heat transfer tube 3 is arranged in the valley portion which is an intermediate position, it is possible to reduce the contact thermal resistance by transferring heat from two places on the cross section of the tube, and the spiral winding becomes easy and the processing cost is low. Leading to In addition, the other of the two refrigerant heat transfer tubes 5 has a single contact with the water heat transfer tube 3 and thus has a slightly higher contact thermal resistance than the case of two locations, but the ease of spiral winding does not change that much. Therefore, it leads to the cost reduction of processing similarly. Since the effects of the other water refrigerant heat exchanger 1 are almost the same as those of the first embodiment, the water refrigerant heat exchanger 1 has an overall shape such as a cylinder and is excellent in space saving, and can be made of materials and processing. From this point, it can be seen that the cost can be reduced, and that the structure of the heat transfer tube that is counterflowing and has low contact heat resistance has the effect of excellent heat exchange performance. Thus, as in the first embodiment, it can be seen that the heat pump type hot water heater can simultaneously achieve downsizing, cost reduction, and high efficiency as the entire device.

  FIG. 4 is a longitudinal sectional view of a water-refrigerant heat exchanger in a heat pump type water heater of still another embodiment (third embodiment) of the present invention.

  In the water-refrigerant heat exchanger 1 according to this embodiment, two refrigerants are provided for each one of the water heat transfer tubes 3 on the outer periphery and the inner periphery of the water heat transfer tube 3 spirally wound so as to have a substantially cylindrical shape as a whole. The heat transfer tube 5 is disposed, and the contact portion between the two is joined over substantially the entire length of the heat transfer tube. The refrigerant heat transfer tubes 5 disposed on the outer periphery and the inner periphery of the water heat transfer tube 3 are spirally wound and joined so as to be disposed in a valley portion that is an intermediate position between the two water heat transfer tubes 3 facing each other. Therefore, as in the first embodiment described above, heat can be transmitted from two locations on the cross section of the tube, so that the contact thermal resistance can be further reduced, and spiral winding is facilitated, leading to lower processing costs (internal). The circumferential refrigerant heat transfer tube 5 is in close contact with the valley portion by applying a compressive force to both ends and fixing the both ends). Since the effects of the other water refrigerant heat exchanger 1 are almost the same as those of the first embodiment, the water refrigerant heat exchanger 1 has an overall shape such as a cylinder and is excellent in space saving, and can be made of materials and processing. From this point, it can be seen that the cost can be reduced, and that the structure of the heat transfer tube that is counterflowing and has low contact heat resistance has the effect of excellent heat exchange performance. Thus, as in the first embodiment, it can be seen that the heat pump type hot water heater can simultaneously achieve downsizing, cost reduction, and high efficiency as the entire device.

  FIG. 5 is a longitudinal sectional view of a water-refrigerant heat exchanger in a heat pump type hot water heater of still another embodiment (fourth embodiment) of the present invention, and FIG. 6 is a water refrigerant in a general heat pump type hot water heater. It is a graph which shows distribution of the refrigerant | coolant side heat transfer coefficient inside a heat exchanger, and water and refrigerant | coolant temperature.

  In the water-refrigerant heat exchanger 1 of this embodiment, the refrigerant heat transfer tube 5 has a spiral winding pitch from the inlet of the refrigerant heat transfer tube 5 around the outer periphery of the water heat transfer tube 3 spirally wound so as to be substantially cylindrical. It is arranged by changing the spiral winding pitch in the length direction of the heat transfer tube so that it is close to the center and the vicinity of the outlet, and rough from the center to the vicinity of the outlet. It is joined over the entire length. The spiral pitch of the refrigerant heat transfer tube 5 was changed in this way because the temperature conditions used as a water heater when the refrigerant is carbon dioxide (for example, refrigerant: 60 to 100 ° C. → 20 ° C., water: 17 ° C. → 40 This is to cope with the phenomenon that the refrigerant passes through the temperature near the critical point inside the water-refrigerant heat exchanger 1 and peaks in the refrigerant-side heat transfer coefficient as shown in FIG. Party, Wang, Tobihara: Proceedings of the 37th Air Conditioning and Refrigeration Union Lecture Meeting, April 2003, p.55-58). When the refrigerant-side heat transfer coefficient reaches a peak in the water-refrigerant heat exchanger 1 at a temperature near the critical point of about 30 ° C., the temperature difference between the water 2 and the refrigerant 4 is slightly lower than that at the center of the heat exchanger. There is a tendency to shrink at a portion near the exit (indicated by A in the figure). In the counterflow heat exchanger, keeping the temperature constant between the two fluids constant rather than fluctuating leads to effective heat exchange as a whole. In this case, the pitch of the refrigerant heat transfer tube 5 is set to have a high refrigerant side heat transfer coefficient. It is possible to improve the overall heat exchange performance by roughening the portion A and making the portions other than A having a low refrigerant side heat transfer coefficient dense. In the water-refrigerant heat exchanger 1 of this embodiment, the overall heat exchange performance is improved by appropriately determining the helical winding pitch of the refrigerant heat transfer tube 5, but the configuration of the other heat exchangers is the same as that described above. Since it is almost the same as the first and second embodiments, the water refrigerant heat exchanger 1 has an overall shape such as a cylinder and is excellent in space saving, and can be reduced in cost from the viewpoint of materials and processing, Moreover, it turns out that it has the effect that it is excellent in heat exchange performance by having the structure of a heat exchanger tube with a counter flow and small contact heat resistance. As a result, as in the first and second embodiments, it can be seen that the heat pump water heater can simultaneously achieve downsizing, cost reduction, and high efficiency as the entire device.

It is the longitudinal cross-sectional view and detailed cross-sectional view of the water-refrigerant heat exchanger in the heat pump type water heater of one Embodiment (1st Embodiment) of this invention. It is a schematic system diagram of the hot water supply system in the heat pump type hot water heater of the first embodiment. It is a longitudinal cross-sectional view of the water refrigerant | coolant heat exchanger in the heat pump type water heater of other embodiment (2nd Embodiment) of this invention. It is a longitudinal cross-sectional view of the water refrigerant | coolant heat exchanger in the heat pump type water heater of other embodiment (3rd Embodiment) of this invention. It is a longitudinal cross-sectional view of the water refrigerant | coolant heat exchanger in the heat pump type water heater of further another embodiment (4th Embodiment) of this invention. It is a graph which shows the refrigerant | coolant side heat transfer rate inside a water refrigerant | coolant heat exchanger in a general heat pump type water heater, and water / refrigerant temperature distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Water refrigerant | coolant heat exchanger, 2 ... Water, 3 ... Water heat exchanger tube, 4 ... Refrigerant, 5 ... Refrigerant heat exchanger tube, 6 ... Joining material, 7 ... Heat pump type hot water heater.

Claims (5)

  A water heat transfer tube through which water circulates and a refrigerant heat transfer tube through which one or a plurality of refrigerants circulate with respect to one of the water heat transfer tubes are in contact with each other in an overall shape such as a substantially cylindrical shape spirally wound together. The water heat transfer tube has a substantially cylindrical shape that is closely wound in the axial direction of a cylinder or the like and spirally wound with almost no gap, and the refrigerant heat transfer tube is a cylinder of the water heat transfer tube or the like. The outer circumference or the inner circumference of the shape or both of them are spirally arranged, and at least one or more of the cross sections of the water heat transfer pipe are joined by brazing or soldering over the entire length of the heat transfer pipe, and A heat pump type hot water heater comprising a water heat exchanger tube and a heat exchanger configured to flow water and refrigerant in opposite directions inside the refrigerant heat exchanger tube.   2. The heat pump type hot water heater according to claim 1, wherein a part of the refrigerant heat transfer tube of the heat exchanger is the same as the water heat transfer tube on an outer periphery and / or an inner periphery of an adjacent intermediate position of the water heat transfer tube. A heat pump type, characterized in that it is spirally wound at a pitch, and a part of the refrigerant heat transfer tube is joined to both of the two water heat transfer tubes facing each other by brazing or soldering over almost the entire length of the heat transfer tube Water heater.   The heat pump type water heater according to claim 1 or 2, wherein a part of the refrigerant heat transfer tube of the heat exchanger is changed in a length direction of the heat transfer tube on an outer periphery or an inner periphery or both of the water heat transfer tube. The pitch of the spiral of the refrigerant heat transfer tube is based on the heat exchange performance inside the refrigerant heat transfer tube in the typical operating state of the heat pump water heater or the temperature difference between water and refrigerant, etc. A heat pump type water heater characterized by   4. The heat pump type hot water heater according to claim 1, wherein the refrigerant is carbon dioxide. The compressor which compresses a refrigerant | coolant, The heat exchanger of Claims 1 thru | or 4 which heat-exchanges the refrigerant | coolant and water from this compressor, and an expansion valve which expands the refrigerant | coolant from this heat exchanger An evaporator that exchanges heat between the refrigerant from the expansion valve and the outside air to evaporate the refrigerant, a hot water storage tank that stores water heated by the refrigerant in the heat exchanger, and distributes water and the refrigerant to a necessary path A heat pump type hot water heater comprising a piping and a control device.

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