JP2009216309A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tubular heat exchanger capable of suppressing blocking of water flow channel and degradation of heat transferring performance caused by attachment of deposited calcium to an inner tube. <P>SOLUTION: A spirally-twisted refrigerant double-tube 2 is disposed in a water pipe 6 to disturb the water flow in the water pipe 6 to be swirl flow, thus heat exchange between the water and carbon dioxide is promoted. Further the heat is transferred to the water in the water pipe 6 also from a refrigerant pipe 7 wound on an outer periphery of the water pipe 6, thus local sudden rise of a water temperature is suppressed by reducing heat flux to the water, the deposition of calcium near a wall surface can be suppressed, and degradation of performance of the heat exchanger 1 can be prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat exchanger for exchanging heat between two fluids such as a fluid such as water and a fluid such as a refrigerant, which is used in a device such as an air conditioner or a hot water supply, in particular, a heat pump type hot water heater.

  Conventionally, this type of heat exchanger includes an inner tube having a coolant channel formed therein and an outer tube provided outside the inner tube and having a water channel formed between the inner tube and the inner tube. A so-called double-tube heat exchanger configured is known (for example, see Patent Document 1).

  9 and 10 show a conventional heat exchanger described in Patent Document 1, FIG. 9 is a plan view of the heat exchanger, and FIG. 10 is a cross-sectional view of a pipe section of the heat exchanger. FIG.

  As shown in FIGS. 9 and 10, the heat exchanger 101 is a double-pipe heat exchanger, and includes two inner pipes 103 that form a refrigerant flow path 102 therein, and an inner pipe 103. A copper outer tube 105 provided on the outside and having a water channel 104 formed between the inner tube 103 and the inner tube 103 is formed.

  The inner pipe 103 includes a copper refrigerant pipe 106 and a copper leak detection pipe 107 provided on the outer periphery of the refrigerant pipe 106, and expands the refrigerant pipe 106 or contracts the leak detection pipe 107. Thereby, the refrigerant | coolant pipe | tube 106 and the leak detection pipe | tube 107 are closely_contact | adhered. A large number of leak detection grooves 108 are formed on the inner surface of the leak detection pipe 107 along the axial direction of the pipe, and an air layer is formed in the leak detection groove 108. Further, the leak detection groove 108 is connected to a leak detection sensor (not shown) provided outside, and the refrigerant or water leaked from the inner tube 103 or the outer tube 105 passes through the leak detection groove 108 to the outside. Leakage is detected by the leak detection sensor.

  The operation of the heat exchanger configured as described above will be described below.

  The heat exchanger 101 is formed by a double tube of an inner tube 103 and an outer tube 105, and the outer periphery of the inner tube 103 exchanges heat with water, and the refrigerant and water heat through the refrigerant tube 106 and the leak detection tube 107. Since they are exchanged, the contact area between the inner tube 103 and water can be increased, and the heat exchange efficiency can be improved.

  Further, even if a hole or a crack is generated in the refrigerant pipe 106 or the leakage detection pipe 107 due to corrosion or the like, and the refrigerant or water leaks, the leakage can be reliably detected through the leakage detection groove 108. The refrigerant pipe 106 and the leak detection pipe 107 form a double boundary wall between the refrigerant and water, and even if a defect such as a hole or a crack occurs in one of the refrigerant and water, There is no risk of mixing.

Therefore, the reliability of the heat exchanger 101 can be maintained high. In addition, since the heat exchanger 101 is of a double tube type, bending can be easily performed, the manufacturing cost can be reduced, and the size can be reduced.
JP 2005-69620 A

  However, in the above-described conventional configuration, tap water or the like containing mineral components such as calcium (Ca) is mainly used for the water flowing in the outer tube 105. , The calcium dissolved in water was deposited, and the precipitated calcium adhered to the outer wall of the inner tube 103 on the heating side.

  As a result, the heat transfer performance between the inner pipe 103 and water is lowered, and there is a problem that a predetermined heat exchange capability cannot be obtained due to secular change.

  In particular, when using tap water with a large amount of calcium precipitation depending on the location, the precipitated calcium becomes a layer, and the layer grows and adheres to the outer wall of the inner tube 103 to reach the inner wall of the outer tube 105. The water flow path 104 may be clogged, and the function of the heat exchanger 101 may stop.

  In order to prevent this, it is conceivable to increase the width of the water flow path 104 between the inner tube 103 and the outer tube 105. However, this configuration reduces the flow rate of water and decreases the heat transfer coefficient on the water side. Therefore, in order to obtain a predetermined heat exchange capacity, it is necessary to lengthen the tube length of the heat exchanger. However, increasing the tube length of the heat exchanger has the problems of increasing the capacity of the heat exchanger 101 more than necessary and increasing the weight.

  The present invention solves the above-mentioned conventional problems, suppresses the adhesion of precipitated calcium to the inner tube to suppress deterioration of heat transfer performance over time, and even when there is a lot of calcium precipitation depending on the location. , Without blocking the water flow path due to the calcium layer adhering to the outer wall of the inner tube thickly, without increasing the heat transfer area of the inner tube by increasing the tube length of the heat exchanger, An object of the present invention is to provide a tubular heat exchanger excellent in heat exchange performance.

  In order to solve the above-described conventional problems, a heat exchanger according to the present invention is disposed inside a first tube in which the fluid A flows inside and spirally twisted with each other. The plurality of second tubes through which the fluid B flows and at least one or more third tubes that are in close contact with the outer periphery of the first tube and through which the fluid B flows are provided.

  In this configuration, since the plurality of second tubes are spirally twisted together and arranged in the first tube, the entire flow of the fluid A flowing in the first tube can be swirled. Thus, the flow of the fluid A can be turbulently disturbed, and the heat of the fluid B can be diffused and transferred to the fluid A of the first pipe.

  Furthermore, at least one or more third tubes through which the fluid B flows are in close contact with the outer periphery of the first tube and are spirally wound around the first tube, so that the first tube The heat of the fluid B is uniformly transmitted to the fluid A from the entire inner wall.

  Thus, in order for the heat exchanger to obtain a predetermined heating capacity, the fluid A can be heated from both the outer wall of the plurality of second tubes and the inner wall of the first tube, and the second tube for the fluid A can be heated. The heat fluxes on the outer wall and the inner wall of the first tube can be kept small.

  Therefore, when the fluid A is water, local rapid increase in water temperature in the vicinity of the outer wall of the second tube and in the vicinity of the inner wall of the first tube is suppressed, and calcium due to the increase in water temperature in the portion where the flow velocity is slow in the vicinity of the wall surface. Precipitation can be suppressed as much as possible, and adhesion of calcium to the wall surface can be suppressed.

  Further, even when the fluid A is water with a large amount of calcium precipitation, the outer wall of the second tube of calcium is used to heat the water while suppressing the heat flux on both the outer wall of the second tube and the inner wall of the first tube. Even if the first pipe does not grow abruptly on the inner wall, and the width of the water flow path between the second pipe and the first pipe is large, the outside of the second pipe The wall surface and the inner wall surface of the first tube can be used as a heat transfer surface, and a predetermined heat exchange capability can be obtained by heating water from both the outer wall surface and the inner wall surface. As a result, it is possible to suppress an increase in the capacity and weight of the heat exchanger without increasing the tube length of the heat exchanger.

  The tubular heat exchanger of the present invention is capable of suppressing the adhesion of precipitated calcium to the inner tube and suppressing a decrease in heat transfer performance due to secular change. In addition, in order to suppress the clogging of the water flow path due to the adhesion of the calcium layer, even when the water flow path width is expanded, a predetermined heat exchange performance can be obtained without increasing the tube length of the heat exchanger, The increase in capacity and weight of the heat exchanger can also be suppressed.

  According to the first aspect of the present invention, a plurality of first pipes in which the fluid A flows are arranged inside the first pipe in a spirally twisted state, and the fluid B flows inside the first pipe. A second tube and at least one third tube that is in close contact with the outer periphery of the first tube and in which the fluid B flows are provided.

  By adopting such a configuration, the entire flow of the fluid A flowing in the first pipe can be turned into a swirl flow. As a result, the flow of the fluid A is turbulently disturbed, and the fluid A of the first pipe is changed. The heat of the fluid B is easily diffused. Furthermore, the third tube is brought into close contact with the outer periphery of the first tube and wound spirally, whereby the heat of the fluid B can be easily transmitted to the fluid A from the entire inner wall of the first tube. .

  As a result, in order for the heat exchanger to obtain a predetermined heating capacity, the outer wall of the plurality of second tubes and the inner wall of the first tube that has received heat transfer from the third tube to the fluid A The fluid A can be heated from both, and the heat flux on the outer wall of the second tube and the inner wall of the first tube with respect to the fluid A can be suppressed small. Therefore, when the fluid A is water, it is possible to suppress a local rapid increase in the water temperature in the vicinity of the outer wall of the second tube and in the vicinity of the inner wall of the first tube, and the water temperature in the portion where the flow velocity is slow in the vicinity of the wall surface. The calcium precipitation due to the rise can be suppressed as much as possible, and the adhesion and growth of calcium on the wall surface can be suppressed.

  In addition, even when the fluid A is water having a large amount of calcium precipitation, the heat flux is suppressed on both the outer wall of the second tube and the inner wall of the first tube to heat the water. The adhesion of the outer wall and the inner wall of the first pipe does not grow abruptly, and even if the water flow path width between the second pipe and the first pipe is set large, the outer wall of the second pipe Both sides of the inner wall of the first tube can be heat transfer surfaces, and heat is easily diffused into the water by heating water from both sides. As a result, a heat exchanger is used to obtain a predetermined heat exchange capacity. The tube length is not increased, and the capacity and weight of the heat exchanger are not increased.

  According to a second aspect of the present invention, in the first aspect of the present invention, the third tube is spirally formed along the twist of the first tube in the spirally twisted first tube. It is a wrapping thing.

  By adopting such a configuration, a difference in distance is periodically provided in both the tube axis direction and the circumferential direction between the outer wall of the plurality of helically twisted second tubes and the inner wall of the first tube. As a result, relatively low temperature water flowing near the center in the width direction of the water flow path between the second pipe and the first pipe, the outer wall of the second pipe, and the vicinity of the inner wall of the first pipe The temperature boundary layer formed by the high temperature water can be continuously disturbed.

  Further, by winding the third tube spirally along the twist of the first tube, the contact area between the first tube and the third tube is increased, and the raised surface formed by the twist is changed to the first surface. Positioning at the time of processing can be made such that the three tubes are in close contact with the first tube. Thereby, the position shift at the time of winding of a 3rd pipe | tube can be suppressed, and the assembly precision of a heat exchanger can be improved.

  According to a third aspect of the present invention, in the first aspect of the present invention, the outer wall peripheral surface of the first pipe is provided with a recess that turns and extends while forming a predetermined interval.

  By setting it as this structure, a recessed part can be formed with high dimensional accuracy and it can be made to match with the twist pitch of a said 2nd pipe | tube. As a result, it is possible to accurately provide a distance in the circumferential direction between the plurality of helically twisted second pipe outer walls with high accuracy, while suppressing an increase in water flow resistance. It was formed by relatively low-temperature water flowing near the center in the width direction of the water flow path between the second pipe and the first pipe, and high-temperature water near the outer wall of the second pipe and the inner wall of the first pipe. The temperature boundary layer can be continuously disturbed.

  Moreover, without adding secondary processing such as torsion processing or spiral drawing processing to the circular pipe, unevenness can be provided in the circumferential direction by the raw pipe processing method such as extrusion processing, and the processing cost can be kept low. it can.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the second tube is thermally connected to an outer tube and an outer peripheral surface is in contact with an inner peripheral surface of the outer tube. It is composed of a double pipe made of a tightly attached inner pipe, and a gap is partially provided on the close contact surface of the inner pipe and the outer pipe.

  With such a configuration, when the fluid A or the fluid B leaks through the gap while keeping the thermal resistance small, the leakage of the fluid A or the fluid B can be detected. Since the space between the fluids B is a double wall, both fluids are difficult to mix and safety is improved.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the fluid A flowing through the first tube and the fluid B flowing through the second tube and the third tube. The flow direction is set so that the fluids A and B are opposed to each other, and the heat of the fluid B is transmitted to the fluid A through the second and third tubes. is there.

  By setting it as this structure, the average temperature difference of the fluid A and the fluid B can be enlarged, a heat exchange amount can be enlarged, and the performance of a heat exchanger can be improved.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the fluid A is water and the fluid B is carbon dioxide.

  Thus, high heat pump efficiency can be obtained by using it as a water-refrigerant heat exchanger for a heat pump water heater.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a plan view of a heat exchanger according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing the structure of the water tube of the heat exchanger and its surroundings along the line AA in FIG. FIG. 3 is a perspective view in which a part of a water pipe constituting the heat exchanger in Embodiment 1 is cut away.

  1 to 3, a heat exchanger 1 includes a copper water pipe (corresponding to the first pipe of the present invention) 6 and a copper refrigerant double pipe (a second pipe of the present invention) disposed in the water pipe 6. The refrigerant double tube 2 is composed of a copper outer tube 3 having a leak detection groove 5 on the inner surface, and a copper tube thermally adhered to the inner surface of the outer tube 3. The inner tube 4 is used. Therefore, the refrigerant double pipe 2 has a structure in which the double wall 2 a is formed by the close contact between the outer pipe 3 and the inner pipe 3. Moreover, the leak detection groove 5 forms a partial gap in the contact surface between the inner tube 3 and the outer tube 2 in the present invention.

  The above-described close contact structure between the outer tube 3 and the inner tube 4 can be formed by a well-known tube expansion method or a tube contraction method.

  The refrigerant double pipe 2 is one in which carbon dioxide flows inside the inner pipe 4, and two of them are arranged in a water pipe 6, and these refrigerant double pipes 2 are spirally twisted with each other, and their spiral centers And the water pipe 6 are contained in the water pipe 6 so that the axes thereof are substantially coaxial. Therefore, a channel through which water flows is formed between the refrigerant double pipe 2 and the inner wall of the water pipe 6.

  A copper refrigerant pipe (corresponding to a third pipe of the present invention) 7 in which carbon dioxide flows inside is spirally wound around the outer circumference of the water pipe 6. The refrigerant pipe 7 is connected to the outer wall of the water pipe 6. It is in close thermal contact with brazing.

  In addition, both ends of the refrigerant double pipe 2 and the refrigerant pipe 7 are connected to the same carbon dioxide inlet 8a and outlet 8b, and water inlet 9a and outlet 9b are provided at both ends of the water pipe 6. It has been. The inflow and outflow directions of the carbon dioxide and water inflow ports 8a and 9a and the outflow ports 8b and 9b are determined so that the carbon dioxide and the water are opposed to each other.

  About the heat exchanger 1 comprised as mentioned above, the operation | movement is demonstrated below.

  First, carbon dioxide flows inside the refrigerant double pipe 2 and the refrigerant pipe 7, and water flows between the refrigerant double pipe 2 in the water pipe 6 so as to face the flow of carbon dioxide, Carbon dioxide and water exchange heat through the double wall 2a of the tube 4. Further, carbon dioxide and water exchange heat from the refrigerant pipe 7 through the wall of the water pipe 6.

  Here, since the leak detection groove 5 is provided on the inner surface of the outer tube 3 between carbon dioxide and water, when carbon dioxide or water leaks through the leak detection groove 5, a detection sensor (not shown) The leak can be detected at.

  Therefore, the heat exchanger 1 can obtain high thermal conductivity through the double wall 2a that secures a sufficient contact area while including the double wall 2a that ensures safety.

  Furthermore, by making the carbon dioxide in the refrigerant double pipe 2 and the refrigerant pipe 7 and the water in the water pipe 6 counter flow, efficient heat exchange can be realized. For example, water-refrigerant for a heat pump water heater By using it as a heat exchanger, high heat pump efficiency can be obtained.

  And since the two refrigerant double pipes 2 are spirally twisted together and arranged in the water pipe 6, the entire water flowing in the water pipe 6 can be turned into a swirl flow. The heat exchange efficiency can be increased by dispersing the heat of carbon dioxide in the water in the water pipe 6.

  In addition, since the refrigerant pipe 7 is spirally wound around and closely adhered to the outer periphery of the water pipe 6, the heat of carbon dioxide can be transmitted to water substantially uniformly from the entire inner wall of the water pipe 6. Thereby, water will be heated from both the outer wall of the two refrigerant | coolant double tubes 2 and the inner wall of the water tube 6 with respect to water, and the heat flux in the outer wall of the refrigerant | coolant double tube 2 with respect to water and the inner wall of the water tube 6 is carried out. The heat exchanger 1 can obtain a predetermined heating capacity.

  Therefore, the local rapid increase of the water temperature in the vicinity of the outer wall of the refrigerant double tube 2 and the vicinity of the inner wall of the water tube 6 can be suppressed, and the precipitation of calcium due to the increase in the water temperature in the portion near the wall surface where the flow velocity is slow can be suppressed as much as possible. It is possible to suppress the adhesion of calcium to the outer wall of the refrigerant double tube 2 and the inner wall of the water tube 6.

  Further, even when water with a large amount of calcium precipitation is used depending on the location, the water is heated while suppressing the heat flux on both the outer wall of the refrigerant double tube 2 and the inner wall of the water tube 6 with respect to water. 2 and the inner wall of the water pipe 6 do not grow suddenly, and even if the width of the water flow path between the refrigerant double pipe 2 and the water pipe 6 is increased, the outer wall of the refrigerant double pipe 2 and the water pipe Since water is heated using both inner wall surfaces of the heat transfer surface 6 as heat transfer surfaces, the heat exchanger 1 can be increased in capacity and weight without increasing the tube length of the heat exchanger 1 in order to obtain a predetermined heat exchange capacity. The accompanying enlargement can be suppressed.

  Further, the pressure loss and heat transfer characteristics on the water side are changed by making the helical pitch of the refrigerant double pipe 2 and the refrigerant pipe 7 coarse and fine and changing the width of the water flow path between the refrigerant double pipe 2 and the water pipe 6. For example, in the case of a heat pump type water heater, performance and specifications such as heating capacity and volume as a water-refrigerant heat exchanger can be designed in a balanced manner and easily according to the conditions. .

  In the first embodiment, brazing is used to fix the refrigerant pipe 7 and the water pipe 6, but the same effect can be obtained by a fixing method in which solder is applied to fix both the refrigerant pipe 7 and the water pipe 6. Furthermore, although the refrigerant pipe 7 is configured to be provided by turning one, a plurality of the refrigerant pipes 7 may be provided by turning similarly. In such a case, since the amount of heat exchange with the refrigerant increases, the performance of the heat exchanger can be improved.

  In the first embodiment, the outer pipe 3, the inner pipe 4, the water pipe 6 and the refrigerant pipe 7 of the refrigerant double pipe 2 are made of copper, but metals such as brass, SUS, corrosion-resistant iron, and aluminum alloy are used. Even if the material is used, the same effect can be obtained.

  Furthermore, in Embodiment 1 of the present invention, the refrigerant flowing in the refrigerant double pipe 2 and the refrigerant pipe 7 is carbon dioxide. However, similar effects can be obtained with a refrigerant such as R410A. is there.

(Embodiment 2)
FIG. 4 is a cross-sectional view showing the structure of the water pipe of the heat exchanger and its surroundings in Embodiment 2 of the present invention. FIG. 5 is a perspective view in which a part of a water pipe constituting the heat exchanger in the second embodiment is cut away.

  In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  4 and 5, a copper water pipe (corresponding to the first pipe of the present invention) 10 is a deformed shape that is twisted so as to be substantially coaxial with the spiral center of two spiral refrigerant double pipes 2. A large-diameter convex portion 10a and a small-diameter concave portion 10b are formed in a spiral shape by the above-described twisting process, and the refrigerant tube 7 is wound spirally along the spiral-shaped concave portion 10b.

  Although the operation of the heat exchanger 1 configured as described above will be described, the heat exchanger 1 in the second embodiment functions in the same manner as in the first embodiment. An operation based on a configuration different from the first embodiment will be mainly described.

  As shown in FIGS. 4 and 5, the water pipe 10 is formed into a deformed pipe with a spiral concave portion 10 b and a convex portion 10 a, and the coolant pipe 7 is wound along the spiral concave portion 10 b, thereby Between the inner wall and the outer wall of the two spiral twisted refrigerant double pipes 2, the distance between the pipe axis direction and the circumferential direction is periodically different, and the refrigerant double pipe 2 and the water pipe 10 are arranged. It is possible to continuously disturb the temperature boundary layer formed by the relatively low temperature water near the center in the width direction of the water channel between and the high temperature water near the wall surfaces of the refrigerant double pipe 2 and the water pipe 10. Therefore, the heat transferability on the water side can be improved.

  Further, by winding the refrigerant pipe 7 spirally along the spiral recess 10 b of the water pipe 10, the contact area between the water pipe 10 and the refrigerant pipe 7 is increased, and at the time of processing for bringing the refrigerant pipe 7 into close contact with the water pipe 10. It becomes difficult to cause a positional shift, and the heat exchanger can be assembled with high accuracy.

  In the second embodiment as well, as in the first embodiment, a plurality of refrigerant pipes 7 may be swiveled.

(Embodiment 3)
FIG. 6 is a cross-sectional view showing the water pipe of the heat exchanger and its peripheral structure in Embodiment 3 of the present invention. FIG. 7 is a perspective view in which a part of a water pipe constituting the heat exchanger in Embodiment 3 is cut away. FIG. 8 is a perspective view in which a part of a water pipe constituting a different heat exchanger of the third embodiment is cut away.

  In addition, about the component same as Embodiment 1, 2, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  6 and 7, copper water pipes (corresponding to the first pipe of the present invention) 11 are spirally separated by a predetermined interval in the circumferential direction by extrusion processing and are approximately parallel to the pipe axis direction ( A plurality of recesses 12 that are recessed inside the water pipe 11 in a swiveling state are provided. Then, the refrigerant pipes 7 corresponding to the respective recesses 12 are fitted, and a plurality of refrigerant pipes 7 are spirally wound around the water pipe 11. In FIG. 7, the refrigerant pipe 7 is indicated by a broken line so that the concave portion 12 can be easily understood.

  The operation of the heat exchanger 1 configured as described above will be described. The heat exchanger 1 according to the third embodiment functions in the same manner as in the first and second embodiments. Here, the operation based on the configuration different from the first embodiment and the second embodiment will be mainly described.

  As shown in FIGS. 6 and 7, by providing a plurality of circumferentially spaced recesses 12 on the outer peripheral surface of the water pipe 11, convexes are formed on the inner wall of the water pipe 11 so as to be spaced apart from each other. The distance between the outer walls of the refrigerant double pipe 2 twisted into a shape is discretely provided in the circumferential direction. Moreover, since the recess 12 has a shallow angle that intersects the tube axis of the water tube 11, the recess 12 has almost no increase in the flow resistance of water, and is near the center in the water flow path width direction between the refrigerant double tube 2 and the water tube 11. The temperature boundary layer formed by the relatively low temperature water and the high temperature water in the vicinity of the wall surfaces of the refrigerant double pipe 2 and the water pipe 11 can be continuously disturbed. Therefore, the heat transferability on the water side can be improved.

  Further, the recess 12 provided in the water pipe 11 can be provided by a raw pipe processing method such as extrusion without adding a secondary process such as a twisting process or a spiral drawing process to the circular pipe, and the processing cost can be kept low. be able to. Furthermore, the amount of material used for the water pipe 11 can be reduced, and the material cost can be reduced.

  The heat exchanger 1 shown in FIGS. 6 and 7 is provided with a plurality of recesses 12 so as to be substantially parallel to the tube axis direction. However, as shown in FIG. It can also be set as the structure which provides at the angle which cross | intersects largely and spirally.

  In such a configuration, the flow resistance of water increases, but the water-side heat transfer can be further improved. Also, the heat exchanger of FIG. 8 may have a configuration in which a plurality of recesses are pivoted and a plurality of refrigerant tubes are fitted into the recesses and swiveled.

  As described above, the heat exchanger according to the present invention does not reduce the cross-sectional area of the water flow path to increase the flow velocity, or increase the pipe length to increase the heat transfer area of the inner pipe. The heat exchange performance of the heat exchanger can be improved, for heat pump water heaters, household and commercial air conditioners, heat pump equipment such as washing machines with a heat pump drying function, and fuel cell applications. Is also applicable.

The top view of the heat exchanger in Embodiment 1 of this invention Sectional drawing which shows the water pipe of the heat exchanger by the AA line of FIG. 1, and the surrounding structure The perspective view which excised a part of water pipe which comprises the heat exchanger in Embodiment 1 Sectional drawing which shows the water pipe of the heat exchanger in Embodiment 2 of this invention, and its surrounding structure The perspective view which excised part of the water pipe which comprises the heat exchanger in Embodiment 2 Sectional drawing which shows the water pipe of the heat exchanger in Embodiment 3 of this invention, and its surrounding structure The perspective view which excised part of the water pipe which comprises the heat exchanger in Embodiment 3 The perspective view which excised part of the water pipe which comprises the different heat exchanger of Embodiment 3 Plan view of a heat exchanger showing a conventional example Sectional view of the pipe section in the same heat exchanger

Explanation of symbols

1 Heat exchanger 2 Refrigerant double pipe (second pipe)
2a Double wall 3 Outer tube 4 Inner tube 5 Leakage detection groove (gap)
6 Water pipe (first pipe)
7 Refrigerant pipe (third pipe)
10 Water pipe (first pipe)
11 Water pipe (first pipe)
12 recess

Claims (6)

  A first pipe through which fluid A flows, a plurality of second pipes disposed inside the first pipe in a spirally twisted manner, and through which the fluid B flows; A heat exchanger comprising at least one or more third tubes that are in close contact with the outer periphery of the tube and in which the fluid B flows.   The heat exchanger according to claim 1, wherein the third tube is spirally wound around the first tube twisted in a spiral shape along the twist of the first tube.   The heat exchanger according to claim 1, wherein a concave portion that turns and extends while forming a predetermined interval is provided on a peripheral surface of the outer wall of the first pipe.   The second pipe is composed of a double pipe made of an outer pipe and an inner pipe whose outer peripheral surface is in thermal contact with the inner peripheral surface of the outer pipe, and a The heat exchanger as described in any one of Claim 1 to 3 which provided the clearance gap between.   The flow directions of the fluid A flowing through the first tube and the fluid B flowing through the second tube and the third tube are set so that the fluids A and B are opposed to each other, and the heat of the fluid B is set. The heat exchanger according to any one of claims 1 to 4, wherein the heat exchanger is transmitted to the fluid A through the second pipe and the third pipe.   The heat exchanger according to any one of claims 1 to 5, wherein the fluid A is water and the fluid B is carbon dioxide.

Images