JP2012242054A - Heat exchanger and heat pump water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further miniaturize a heat exchanger by improving piping density by reducing clearance gaps while spirally configuring heat exchange pipes.SOLUTION: This heat exchanger includes two heat exchange pipes 15, 16 configured by fixing one or a plurality of refrigerant pipes 12 in which a refrigerant is circulated, around a water pipe 11 in which water is circulated, each of the heat exchange pipes 15, 16 is spirally formed with a clearance gap between an inner periphery and an outer periphery of the spiral, and two heat exchange pipes 15, 16 are assembled into the double spiral shape by vertically fitting each of two heat exchange pipes 15, 16 to the clearance gap of the other spiral.

Description

  The present invention relates to a heat exchanger that can be suitably used as a condensation heat exchanger, and a heat pump water heater.

  In recent years, natural refrigerant heat pump hot water supply devices have been developed as hot water supply devices that can exhibit high energy saving performance and environmental performance. In order to further improve the COP (coefficient of performance) of such a heat pump hot water supply apparatus, it is regarded as one of the important issues to improve the performance of a hot water supply heat exchanger that functions as a condenser. Various heat exchangers as exemplified in 3 have been proposed.

Japanese Patent No. 4437487 Japanese Patent No. 3913629 JP 2009-243792 A

  The twisted tube heat exchanger described in Patent Document 1 is provided with a plurality of mountain valley bottoms spirally around the outer periphery of the water pipe, and a plurality of refrigerant pipes are spirally wound around the outer periphery of the water pipe. It is configured in an elliptical coil shape (see FIG. 3 of the same document) or an elliptical spiral shape (see FIG. 8 of the same document).

  The heat exchanger described in Patent Document 2 includes a refrigerant pipe (first heat transfer pipe) having a flow path through which refrigerant flows, and a water pipe (second heat transfer pipe) having a flow path through which water flows. A refrigerant pipe is embedded and integrated in a water pipe to form a coupling pipe, and the coupling pipe is bent into a spiral shape to constitute a heat exchanger body.

  The heat exchanger described in Patent Document 3 includes a heat transfer tube group including a plurality of first heat transfer tubes (water piping) and second heat transfer tubes (refrigerant piping), and the first heat transfer tubes are in contact with each other. The second heat transfer tubes are arranged along the first heat transfer tubes so as to come into contact with both of the first heat transfer tubes adjacent to one side of the first heat transfer tubes. It is formed in a spiral shape that is wound around the second heat transfer tube side while alternately repeating a portion and a bent portion that bends approximately 90 ° with a constant bending radius.

  In any of the above-mentioned Patent Documents 1 to 3, the idea of realizing a high-density winding shape by folding a coupling pipe in which a refrigerant pipe is embedded in the outer periphery of a water pipe through which water flows is disclosed. ing. However, the water pipes that make up the heat exchanger of the natural refrigerant heat pump water heater and the copper pipes that make up the refrigerant pipes are required to be thinner and stronger in order to further improve heat exchange efficiency. Because it is difficult to bend a thin high-strength copper tube into a spiral shape without any gaps, even if it is processed into a spiral shape, if the special processing machine is not used, the inner and outer circumferences of the spiral The actual situation is that it can only be processed into a shape having a gap with the part. In such a spiral configuration having a gap, the pipe density cannot be increased, and the heat exchanger cannot be reduced in size.

  Accordingly, an object of the present invention is to improve the pipe density by reducing the gap while forming the spiral shape of the heat exchange pipe, thereby reducing the size of the heat exchanger.

  In order to achieve the above object, the present invention takes the following technical means.

  That is, the heat exchanger according to the present invention has two heat sources in which one or a plurality of second heat transfer tubes through which the second fluid flows are arranged and fixed so as to transfer heat around the first heat transfer tubes through which the first fluid flows. Each of the heat exchange pipes is formed in a spiral shape having a gap between the inner peripheral part and the outer peripheral part of the spiral, and the two heat exchange pipes are fitted into the other spiral gap in the vertical direction. Thus, it is assembled in a double spiral shape (claim 1).

  According to the heat exchanger of the present invention, each heat exchange pipe is formed in a spiral shape having a gap, so that it is relatively easy to bend in the same direction without using a special pipe processing device. It can be formed easily. And since two heat exchange pipes bent into a spiral shape with a gap are assembled into a double spiral shape by fitting them into the other spiral gap, work efficiency is improved by the gap during the spiral bending process. However, after assembly, the gap is filled with the other heat exchange pipe, so that a high-density pipe configuration can be obtained, and the heat exchange efficiency can be improved while reducing the size of the heat exchanger. .

  In addition, when using the heat exchanger of this invention as a condenser of a heat pump hot-water supply apparatus, it is preferable that a 1st heat exchanger tube is a water pipe (hot-water supply pipe), and a 2nd heat exchanger tube is a refrigerant | coolant pipe, Each second heat transfer tube is preferably configured to have a smaller diameter than the first heat transfer tube.

  In the heat exchanger of the present invention, inner end portions of both heat exchange pipes may be connected to each other at the center of the spiral (claim 2). According to this, it is necessary to allow a certain amount of cavity to be generated in the spiral center part, but by using the cavity part of the spiral center part as a connection part of both heat exchange pipes, it is possible to further increase the cavity part. It becomes possible to improve the piping density.

  Further, the heat exchange pipes assembled in a double spiral shape can be further stacked in a plurality of stages (Claim 3). According to this, the pipe length can be made a multiple according to the number of stacked stages without increasing the size of the outer periphery of the spiral, and the pipe density can be further improved with a limited installation area. .

  Moreover, according to the heat pump water heater provided with the heat exchanger of the present invention as a condenser (Claim 4), it is possible to reduce the size of the whole water heater by reducing the size of the condenser. The COP can be further improved by increasing the density of the vessel.

  As described above, according to the heat exchanger according to claim 1 of the present invention, the two heat exchange pipes bent into a spiral shape having a gap are fitted into the other spiral gap. Since it is assembled in a double spiral shape, the work efficiency is improved by the gap during the spiral bending process, but after the assembly, the gap is filled with the other heat exchange pipe, resulting in a high-density pipe configuration. Further, it is possible to improve the heat exchange efficiency while reducing the size of the heat exchanger.

  Moreover, according to the heat exchanger which concerns on Claim 2 of this invention, the further improvement of piping density can be aimed at by utilizing the hollow part of a spiral center part as a connection part of both heat exchange piping.

  Further, according to the heat exchanger according to claim 3 of the present invention, the pipe length can be made a multiple according to the number of stacked stages without increasing the size of the outer periphery of the spiral, and the installation area is limited. It is possible to further improve the piping density.

  Moreover, according to the heat exchanger which concerns on Claim 4 of this invention, while the size reduction of the whole hot water supply apparatus can be achieved by size reduction of a condenser, further increase of COP by density increase of a condenser is attained. Improvements can be made.

1 is an overall perspective view of a heat exchanger according to an embodiment of the present invention. It is a whole perspective view of the heat exchange piping assembly which comprises the heat exchanger. The whole heat exchange piping assembly | attachment body is shown, (a) is a top view, (b) is a front view. It is a top view of the 1st heat exchange piping which comprises the same heat exchange piping assembly. It is a top view of the 2nd heat exchange piping which comprises the same heat exchange piping assembly. It is a piping circuit diagram of the heat pump hot-water supply apparatus which uses the same heat exchanger as a condenser.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

FIGS. 1-5 shows the heat exchanger 1 which concerns on embodiment of this invention, FIG. 6 shows the piping circuit structure of the natural refrigerant | coolant heat pump hot water supply apparatus which used this heat exchanger 1 as a condenser. First, the overall configuration of the heat pump hot water supply apparatus will be described. As shown in FIG. 6, the heat pump hot water supply apparatus is a combination of a refrigerant circulation circuit 2 and a hot water supply circuit 3, and uses a single-stage vapor compression refrigeration cycle to supply hot water. The water of the circuit 3 can be heat exchange heated. In the refrigerant circulation circuit 2, a compressor 21, a condenser (condensation heat exchanger) 1, an expansion valve 22 as a pressure reducing means, and an evaporator (heat source heat exchanger) 23 are connected in order through a refrigerant circulation pipe 24. Is. As the refrigerant circulating in the refrigerant circuit 2, an HC refrigerant such as propane or an appropriate refrigerant such as CO ₂ can be used. The hot water supply circuit 3 pressure-feeds water from the hot water storage tank 31, a water circulation pipe 32 that circulates hot water stored in the hot water storage tank 31 between the condenser 1 and the bottom of the hot water storage tank 31 to the condenser 32. A water supply pump 33 that leads from the condenser 1 to the top of the hot water storage tank 31 after heating is provided. Then, the refrigerant circulation circuit 2 and the hot water supply circuit 3 are controlled by the controller 4 so that the water in the condenser 1 is heated to a set hot water temperature set in a remote controller (not shown) and stored in the hot water storage tank 31. It has become so.

  The compressor 21 is operated by an electric motor, and the operation of the compressor 21 is controlled by the controller 4 with the rotation speed as an operation control amount. The number of revolutions is changed and controlled by changing the operating frequency given from the controller 4. In order to compress to a higher pressure, the rotational speed is increased, and to lower the pressure, the rotational speed is decreased. By being compressed by the compressor 21, the high-temperature gas-phase refrigerant is discharged from the compressor 21 to the refrigerant circulation pipe 24, the discharge temperature is detected by the discharge temperature sensor 25, and the detected discharge temperature is output to the controller 4. Will be.

  The condenser 1 is connected to a water circulation pipe 22 so that water (first fluid) flows, and the condenser 1 is connected to a refrigerant circulation pipe 24 and refrigerant (second fluid) flows. Heat exchange is performed with the second heat transfer tube (refrigerant tube) 12. That is, the high-temperature gas-phase refrigerant discharged from the compressor 21 to the refrigerant circulation pipe 24 and the water supplied from the bottom of the hot water storage tank 31 by the water supply pump 33 are heat-exchanged, and the water becomes hot water by heat exchange heating. The refrigerant that has been deprived of heat by the heat exchange condenses and changes into a liquid phase. The condensation temperature at the time of this phase change is detected by the condensation temperature sensor 13, and this detected condensation temperature is output to the controller 4. The detection of the condensing temperature by the condensing temperature sensor 13 is to detect the temperature of the refrigerant at an intermediate position in the heat exchange process in the condenser 1.

  The expansion valve 22 depressurizes the refrigerant that has become a liquid phase in the condenser 1. The operation of the expansion valve 22 is controlled by the controller 4 using the opening degree as an operation control amount.

  The evaporator 23 includes a fan 23a that blows outside air by its rotational operation, and heat exchange is performed between the outside air and the refrigerant decompressed by the expansion valve 22, so that the refrigerant is evaporated and converted into a gas phase state. It has become. The refrigerant in the gas phase is compressed again in the compressor 21 to be in a high temperature gas phase.

  On the other hand, in the hot water supply circuit 3, when the water in the hot water storage tank 31 is pumped to the condenser 1 by the operation of the water supply pump 33, the incoming water temperature before heat exchange heating is measured by the incoming water temperature sensor 34 before the inlet of the condenser 1. The detected incoming water temperature is output to the controller 3. Further, when the hot water is heated by heat exchange by passing through the condenser 1, the hot water temperature is detected by the hot water temperature sensor 35 on the outlet side of the condenser 1, and this detected hot water temperature is output to the controller 4. It has become. In addition, the outside air temperature is detected by the outside air temperature sensor 36 and output to the controller 4. The hot water heated by the condenser 1 is returned to the top side of the hot water storage tank 31 and stored, and used for subsequent hot water supply. If the amount of hot water in the hot water storage tank 31 decreases due to hot water supply, water is supplied accordingly.

  Next, a preferred embodiment of the heat exchanger 1 used as a condenser in the heat pump water heater will be described in detail with reference to FIGS.

  The heat exchanger 1 of the present embodiment is configured by a heat exchange pipe in which four second circular heat transfer pipes 12 are arranged and fixed so as to be capable of heat transfer around a first heat transfer pipe 11 having a circular cross section. 2 and FIG. 3, the heat exchange pipe assembly 14 configured in a double spiral shape is stacked and arranged in three stages as shown in FIG. Each heat exchange pipe assembly 14 includes a first heat exchange pipe 15 formed in a spiral shape shown in FIG. 4 and a second heat exchange pipe 16 formed in a spiral shape shown in FIG. It is configured by assembling in a spiral shape.

  Each of the heat exchange pipes 15 and 16 is formed in a spiral shape having a gap between the inner peripheral portion and the outer peripheral portion of the spiral, and is formed in a substantially rectangular spiral shape in a plan view in the present embodiment. . The space between the spirals is slightly larger than the cross-sectional width of the midway portion of the spiral of each of the heat exchange pipes 15 and 16. Such a rectangular spiral shape can be obtained by bending a straight pipe in one direction at several locations for each predetermined dimension. Also, the presence of the above-mentioned gap improves work efficiency and facilitates high production. Therefore, the heat exchange pipes 15 and 16 can be processed. Further, the heat exchange pipes 15 and 16 may be configured by individually bending the first heat transfer pipe 11 and the second heat transfer pipe 12 into a spiral shape and then fixing both heat transfer pipes by brazing or the like. Alternatively, the second heat transfer tube 12 may be fixed around the first heat transfer tube 11 and the heat transfer tubes 11 and 12 may be simultaneously bent into a spiral shape.

  The second heat transfer pipe (refrigerant pipe) 12 of each heat exchange pipe 15, 16 has a smaller diameter than the first heat transfer pipe (water pipe) 11, and the axial directions of both are arranged in parallel. The four second heat transfer tubes 12 are respectively disposed on the spiral outer peripheral side upper portion, the spiral outer peripheral side lower portion, the spiral inner peripheral side upper portion, and the spiral inner peripheral side lower portion of the first heat transfer tube 11.

  These heat exchange pipes 15 and 16 are fitted into the other spiral space from above and below to constitute the heat exchange pipe assembly 14. In this assembly 14, as shown in FIG. 3, a minute gap is formed between the first heat transfer pipes 11 and the second heat transfer pipes 12 of the first and second heat exchange pipes 15 and 16. This prevents heat from leaking in the middle of the water and refrigerant circulation paths. In order to stably secure such a minute gap, a spacer may be embedded in a predetermined portion, or the first and second heat exchange pipes 11 and 12 may be brazed and fixed together. .

  In addition, the first and second heat transfer tubes 11 and 12 of the heat exchange pipes 15 and 16 are connected to each other at their inner peripheral ends at the spiral central part, and the first and second heat transfer pipes 15 and 16 are connected to each other. The water and the refrigerant that have flowed from the outer peripheral end of either one of the heat exchange pipes 15 and 16 heat the water by exchanging heat between the water and the refrigerant while passing through both the heat exchange pipes 15 and 16. Then, it flows out from the other outer peripheral side end. In addition, it is good for the flow direction in the heat exchange piping 15 and 16 to make water and a refrigerant | coolant reverse.

  Any connection method may be used at the spiral center of the first and second heat transfer tubes 11 and 12, but in this embodiment, the first heat exchange pipe 16 can be slid in the axial direction on the inner peripheral side end of one heat exchange pipe 16. Connecting pipes 19 and 20 are provided, and when assembling both heat exchange pipes 15 and 16 from above and below, the connection pipes 19 and 20 are retracted, and after assembling, the connection pipes 19 and 20 are connected to the other heat exchange pipe. The connection is made by sliding toward the inner peripheral side end of 15. The connection pipes 19 and 20 are preferably brazed and fixed after connection.

  The end portions on the outer peripheral side of the heat exchange pipes 15 and 16 are formed at substantially the same position in the circumferential direction. In the heat exchange pipe 15 located on the outer peripheral side, the outer peripheral side end portion of the first heat transfer tube 11 protrudes in a straight tube shape, and the outer peripheral side end portion of the second heat transfer tube 12 is bent and formed outward and forward. ing. Further, in the heat exchange pipe 16 located on the inner peripheral side at the outer peripheral side end, the outer peripheral side end of the first heat transfer pipe 11 is similarly projected in a straight tube shape, but the outer heat exchange pipe The first heat transfer tubes 11 are shorter than the first heat transfer tubes 11, and the second heat transfer tubes 12 of the heat exchange pipes 16 on the inner peripheral side are bent toward the front and rear and the inside.

  As shown in FIG. 1, the first heat transfer pipe 11 of the lowermost first heat exchange pipe 15, the first heat transfer pipe 11 of the middle first heat exchange pipe 15, and the second heat exchange pipe 16 of the middle stage. The first heat transfer pipe 11 and the first heat transfer pipe 11 of the uppermost second heat exchange pipe 16, the second heat transfer pipe 12 of the lowermost first heat exchange pipe 15 and the first heat exchange pipe 15 of the middle stage. The second heat transfer pipe 12, the second heat transfer pipe 12 of the second heat exchange pipe 16 in the middle stage, and the second heat transfer pipe 12 of the second heat exchange pipe 16 in the uppermost stage are respectively U-shaped pipe connections. The members 17 and 18 are connected. Thereby, the water which flowed in from the outer peripheral side end part of the 1st heat exchanger tube 11 of the 2nd bottom heat exchange pipe 16 is the 2nd bottom heat exchange pipe 16 and the 1st bottom heat exchange pipe. 15, the first heat exchange pipe 15 in the middle stage, the second heat exchange pipe 16 in the middle stage, the second heat exchange pipe 16 in the uppermost stage, and the first heat exchange pipe 15 in the uppermost stage in order, It flows out from the outer peripheral side end of the first heat transfer pipe 11 of the upper first heat exchange pipe 15.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, only one second heat transfer tube may be arranged and fixed around the first heat transfer tube, and the number of the second heat transfer tubes may be two, three, or five or more. In the above embodiment, the first heat transfer tube and the second heat transfer tube are formed by processing a straight tube having a circular cross section into a spiral shape. However, a coupling tube as described in Patent Documents 1 and 2 is used. It is also possible to adopt. Further, in the above embodiment, the first and second heat exchange pipes 15 and 16 are connected to each other at the center portion of the spiral, but are connected at the outer peripheral end portion of the spiral, and the opening end portion of the spiral center portion is connected to each other. It can also be used as an inlet / outlet for fluid (water and refrigerant).

1 Heat exchanger (condenser)
11 1st heat transfer tube (water tube)
12 Second heat transfer tube (refrigerant tube)
15 1st heat exchange piping 16 2nd heat exchange piping

Claims (4)

  The heat exchange pipe includes two heat exchange pipes in which one or a plurality of second heat transfer pipes through which the second fluid flows circulates and is fixed around the first heat transfer pipe through which the first fluid flows. The spiral is formed in a spiral shape having a gap between the inner peripheral portion and the outer peripheral portion of the spiral, and the two heat exchange pipes are vertically fitted into the other spiral gap to form a double spiral. A heat exchanger characterized by being attached.   The heat exchanger according to claim 1, wherein inner end portions of both heat exchange pipes are connected to each other at the center of the spiral.   The heat exchanger according to claim 1 or 2, further comprising a plurality of stacked layers of heat exchange pipes assembled in a double spiral shape.   A heat pump hot water supply apparatus comprising the heat exchanger according to claim 1 as a condenser.

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