JP6687022B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a heat exchanger that exchanges heat between fluids.

  Conventionally, as this type of heat exchanger, a heat exchanger in which a water pipe and a refrigerant pipe are wound in a double spiral shape has been proposed (for example, see Patent Document 1). Further, a heat exchanger in which a refrigerant pipe is wound around a water pipe has been proposed (for example, Patent Document 2).

  A heat pump water heater equipped with this type of heat exchanger is a device that boils hot water mainly at night for a certain period of time, and the flow velocity of water flowing through the heat exchanger of the water heater during the boiling operation. Is relatively small.

  Therefore, since the flow of water flowing through the heat exchanger is laminar, in order to improve the heat transfer performance of the heat exchanger, the water flow should be disturbed to improve the heat transfer performance on the water side. Is mandatory.

  FIG. 11 is a schematic view (partially sectional view) of a conventional heat exchanger described in Patent Document 1. FIG. 12 is an enlarged view showing a cross section of the heat exchanger of FIG. 11.

  The heat exchanger 201 includes a water pipe 202 and one or more refrigerant pipes 203 for one water pipe 202. The water pipe 202 is formed into a substantially cylindrical shape by being spirally wound. The refrigerant pipe 203 is spirally wound around the water pipe 202 formed in a substantially cylindrical shape at a predetermined pitch. Further, at least one place of the refrigerant pipe 203 is joined over substantially the entire length of the water pipe 202. The flow direction of water flowing through the water pipe 202 is opposite to the flow direction of the refrigerant flowing inside the refrigerant pipe 203.

  As the water pipe 202 is spirally wound as described above, a centrifugal force acts on the water flowing through the water pipe, and a secondary flow as shown by the arrow in FIG. 12 is generated in the cross section perpendicular to the pipe axis. . Here, the magnitude of the centrifugal force that acts on the water flowing through the spiral flow path is based on the balance of forces,

Is expressed as In the formula (1), F is centrifugal force, M (M = V × ρ) is mass, V is volume, ρ is density, v is rotational speed, and r is rotational radius.

  As can be seen from the equation (1), a fluid having a lower temperature and a higher density has a larger centrifugal force, and moves toward the outside of the spiral flow path. Therefore, the temperature difference between the water and the refrigerant on the heat transfer surface increases, and heat transfer is promoted.

  Therefore, even if the flow of water is laminar, the secondary flow improves the temperature field in the cross section perpendicular to the main flow, which is significantly larger than that of a straight tube heat exchanger in which a water pipe and a refrigerant pipe are joined. The heat transfer performance can be improved.

  FIG. 13 is a schematic view of a conventional heat exchanger described in Patent Document 2.

  The heat exchanger 301 includes a water pipe 302 having a straight line portion and one or more refrigerant pipes 303 for one water pipe 302. The refrigerant pipe 303 is wound around the water pipe 302, and a twisting tape is inserted inside the water pipe 302 as a heat transfer promoting means.

  In this way, by inserting the twisting tape into the water pipe and generating the swirling flow, the flow on the water side is disturbed and the heat transfer performance is improved.

  However, in the configuration described in Patent Document 1, since the heat exchanger is formed by spirally winding the pipe, depending on the material of the pipe, the pipe diameter and the wall thickness, the water pipe may be flat or the seat You may bend.

  Therefore, it is necessary to increase the wall thickness of the water tube in consideration of the thinning due to flattening and to increase the curvature diameter D of the spiral tube so that buckling does not occur. This leads to an increase in cost and increases the volume of the heat exchanger. Further, there is a problem that the effect of promoting heat transfer in the secondary flow due to the centrifugal force becomes small.

  Further, if the winding pitch of the pipe is widened, the risk of buckling is reduced, but there is also a problem that it becomes a redundant heat exchanger with many dead spaces and the volume of the heat exchanger becomes unnecessarily large. Was there.

  Further, in the configuration of Patent Document 2, the temperature distribution near the heat transfer surface is improved by the swirling flow generated by the twisting tape, but the temperature distribution on the central axis of the water pipe farthest from the heat transfer surface is improved. The improvement effect of is smaller than that near the heat transfer surface.

  That is, a dead water region where the contribution of heat transfer is small is formed on the central axis of the water pipe. Further, if the diameter of the water pipe is reduced to reduce the dead water area, the water pressure loss becomes excessive and the power of the water transfer pump increases. As a result, there is a problem that the running cost of the device equipped with the heat exchanger increases.

Japanese Patent No. 4805179 Japanese Patent No. 4501446

  The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a heat exchanger that is compact, has excellent economical efficiency, and has high quality performance and high heat exchange performance.

In order to achieve the above object, the refrigeration cycle apparatus of the present invention, at least a compressor, a heat exchanger, a pressure reducing device, and a refrigerant circuit annularly connected to the evaporator, a control device, was compressed by the compressor A high-temperature refrigerant passes through the heat exchanger and the pressure reducing device, flows into the evaporator, melts frost on the evaporator, and is defrosted to be sucked into the compressor. exchanger, and the inner tube which water flows, and insert that is inserted into the inner tube, provided on an outer periphery of the inner tube, having a an outer tube in which the refrigerant flows, said insert is shaft portion And a spiral protrusion formed on the outer surface of the shaft portion, the water flows in a spiral flow path formed by the inner surface of the inner tube, the shaft portion and the spiral protrusion, flow of the refrigerant and the water is configured to be counter-flow, wherein the defrosting operation mode, before The water flow in the heat exchanger is stopped, the insert is made of resin.

Thus, by forming a part of the water flow path with a resin having a larger specific heat than metal, the heat storage amount of the heat exchanger increases, and a larger amount of heat can be utilized from the heat exchanger during defrosting.

Therefore, the defrosting operation can be completed in a short time, and the defrosting performance of the device is improved.

As a result , the spiral flow passage through which water flows can be formed of two parts, the inner pipe and the insert having the spiral protrusion, so that it is not necessary to wind the inner pipe to form the flow passage. Therefore, since the inner tube does not buckle or flatten, the wall thickness of the tube can be minimized and a lightweight heat exchanger with excellent economy can be provided.

  Further, since the curvature diameter of the spiral flow passage can be set smaller than that of the conventional one, it is possible to provide a compact heat exchanger having a large effect of promoting heat transfer by the secondary flow.

In addition , the maximum distance from the heat transfer surface of water is determined by the shaft diameter of the insert and the height of the protrusion of the spiral protrusion. Accordingly, the pitch of the spiral protrusions can be changed so that the flow passage cross-sectional area has a water pressure loss that the water transport pump can tolerate. Therefore, it is possible to provide a heat exchanger with high heat exchange performance in which the dead water area is significantly reduced within the water pressure loss restriction range.

  According to the present invention, it is possible to provide a compact and economical heat exchanger having high quality performance and high heat exchange performance.

1 is a schematic diagram of a heat exchanger according to a first embodiment of the present invention. FIG. 2A is a perspective view showing a fluid flow in an outer pipe of the heat exchanger according to the first embodiment of the present invention. FIG. 2B is a perspective view showing the flow of fluid in the inner tube of the heat exchanger. FIG. 3 is an enlarged view of part A of FIG. FIG. 4 is a diagram showing a trial calculation result of a heat transfer coefficient in the spiral circular tube. FIG. 5A is an external view of an insert of the heat exchanger according to the second embodiment of the present invention. FIG. 5B is an enlarged view of part B of FIG. 5A. FIG. 6A is a sectional view of a heat exchanger according to the second embodiment of the present invention. FIG. 6B is an enlarged view of part C of FIG. 6A. FIG. 7 is a perspective view of a joint and an insert of the heat exchanger according to the second embodiment of the present invention. FIG. 8 is a detailed cross-sectional view of the heat exchanger according to the third embodiment of the present invention. FIG. 9 is a diagram showing a relationship between the tip end width of the insert and the heat exchange capacity. FIG. 10: is a schematic block diagram of the refrigerating-cycle apparatus in Embodiment 4 of this invention. FIG. 11 is a schematic view of a conventional heat exchanger. FIG. 12 is an enlarged view showing a cross section of the heat exchanger of FIG. 11. FIG. 13 is a schematic view of another conventional heat exchanger.

A refrigeration cycle apparatus according to a first aspect of the present invention includes a refrigerant circuit in which at least a compressor, a heat exchanger, a decompression device, and an evaporator are connected in an annular shape, a control device, and a high-temperature refrigerant compressed by the compressor, The heat exchanger and the decompressor, the defrosting operation mode of flowing into the evaporator, melting the frost of the evaporator, and sucked into the compressor, the heat exchanger is and the inner tube from flowing, and insert that is inserted into the inner tube, provided on an outer periphery of the inner tube, having a an outer tube in which the refrigerant flows, said insert includes a shaft portion of the shaft portion and a spiral projection formed on an outer surface, the water flows through the spiral flow path formed by the inner surface of the inner tube and the shaft portion and the helical projection, the said water coolant is configured such that flow between the counter flow, wherein the defrosting operation mode, in the heat exchanger Serial water flow is stopped, the insert is made of resin.

Thus, by forming a part of the water flow path with a resin having a larger specific heat than metal, the heat storage amount of the heat exchanger increases, and a larger amount of heat can be utilized from the heat exchanger during defrosting.

Therefore, the defrosting operation can be completed in a short time, and the defrosting performance of the device is improved.

Also, the spiral flow path through which water flows can be formed by two parts, an inner tube and an insert having a spiral protrusion .

Thereby , the inner tube does not buckle or flatten, and it is possible to provide a lightweight heat exchanger with excellent economical efficiency in which the wall thickness of the tube is minimized.

  Further, since the curvature diameter of the spiral flow passage can be made smaller than that of the conventional one, it is possible to provide a compact heat exchanger having a large effect of promoting heat transfer by the secondary flow.

In addition , the longest distance from the heat transfer surface of water is set to the axial diameter of the insert and the height of the spiral protrusion, and the flow passage cross-sectional area can be set to a pressure loss that the transport pump can tolerate .

As a result , it is possible to provide a heat exchanger having a higher heat exchange performance than the conventional one in which the dead water area is significantly reduced within the pressure loss restriction range.

A second invention is, in particular, the heat exchanger of the first aspect of the invention, which consists in the same way direction from the helical direction of the winding direction and the spiral protrusion of the outer tube.

As a result, the water and the refrigerant can exchange heat with each other in a counterflow, so that a heat exchanger with high heat exchange performance can be provided.

In a third aspect of the invention, particularly in the heat exchanger of the first or second aspect of the invention, the outer pipe is arranged on the outer periphery of the inner pipe at a portion facing the spiral flow path.

As a result, the water and the refrigerant can exchange heat in substantially the entire area of the heat exchanger, so that it is possible to provide a heat exchanger having higher heat exchange performance.

A fourth aspect of the invention is the heat exchanger according to any one of the first to third aspects of the present invention , which further includes joints for fixing the inner pipe and the insert.

As a result, in any installation state (vertical installation, horizontal installation, diagonal installation), the placement position of the insert body having the spiral projection in the inner tube is fixed, and thus a heat exchanger with improved installation flexibility is provided. it can.

A fifth aspect of the invention is a heat exchanger according to any one of the first to fourth aspects of the invention, in which t1 <t2 when the tip width of the spiral protrusion is t1 and the root width is t2.

Thus, to the refrigerant flowing through the inside of the outer tube, because it can enlarge the heat transfer area of the formed flow Ru water spiral flow path between the inner tube and the insert, the heat exchange performance high heat exchanger Can be provided .

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

(Embodiment 1)
FIG. 1 is a schematic diagram (partial cross-sectional view) of a heat exchanger 11 according to Embodiment 1 of the present invention.

  The heat exchanger 11 according to Embodiment 1 of the present invention is inserted into the inner tube 1, the outer tube 3 spirally wound so as to be in close contact with the outer surface of the inner tube 1, and the inner tube 1. It is composed of an insert body 2. The insert 2 is composed of an insert shaft 21 and a spiral projection 22.

  The spiral winding direction of the outer tube 3 and the spiral direction of the spiral protrusion 22 are the same direction, and the winding pitch is also the same.

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

  The heat exchanger 11 is configured such that water, which is the first fluid, and carbon dioxide, which is the second fluid, exchange heat with each other via the inner pipe 1 and the outer pipe 3.

  In the heat exchanger 11, the flow path of water is a spiral flow path formed by the inner surface of the inner tube 1, the outer surface of the insert body shaft portion 21, and the adjacent spiral projections 22, 1 and an insert 2 inserted into the inner tube 1 are formed.

  Therefore, since it is not necessary to perform a bending process to form the water flow path, the inner pipe 1 does not buckle or flatten, and the wall thickness of the inner pipe 1 is a design concept (wall thickness in consideration of pressure + rot). The minimum wall thickness based on (age). This makes it possible to provide a lightweight heat exchanger with excellent economy.

  Next, the curvature diameter D of the spiral flow path and the heat transfer coefficient in the tube will be described.

  The heat transfer coefficient in the developed region in a curved circular pipe such as a spiral pipe is shown as follows in the Japan Society of Mechanical Engineers Heat Transfer Engineering Material Revised 5th Edition.

  Here, Nu represents the Nusselt number, Pr represents the Prandtl number, and Re represents the Reynolds number. D is the curvature diameter of the central axis of the spiral flow path, and d is the equivalent diameter of the tube. FIG. 4 is a trial calculation of Nusselt number Nu when (d / D) was changed under the conditions of Reynolds number Re = 2000 and water temperature of 40 ° C. by using the above formula (3). The vertical axis represents the Nusselt number Nu, and the horizontal axis represents d / D.

  As can be seen from the formulas (2) and (3) and FIG. 4, under the same Reynolds number and the Prandtle number, the larger the equivalent diameter d of the pipe or the smaller the curvature diameter D is, Nusselt number becomes large.

  That is, since the heat transfer coefficient in the pipe is increased, the heat transfer performance of the heat exchanger is improved. The (d / D) of the heat exchanger similar to that of Patent Document 1 mounted on the existing heat pump water heater is 0.2 or less. On the other hand, in the heat exchanger 11 of the present invention, since the spiral flow passage is composed of two parts, the curvature diameter D of the spiral flow passage through which water flows can be made significantly smaller than in the conventional case. . Therefore, (d / D) is increased, and the stirring effect due to the secondary flow is increased. As a result, the heat transfer promotion effect is improved, and a compact heat exchanger can be provided.

  2A and 2B are perspective views showing the flow of fluid flowing through the heat exchanger 11 according to Embodiment 1 of the present invention.

  Water, which is the first fluid, flows through a spiral flow path formed by the inner surface of the inner tube 1, the outer surface of the insert shaft portion 21, and the adjacent spiral protrusion 22. The pitch between the spiral projection 22 of the insert 2 and the winding direction is synchronized, and carbon dioxide, which is the second fluid flowing inside the outer tube 3 wound around the opposite portion of the spiral flow path, and the first Water, which is a fluid, is configured to exchange heat.

  Here, since water flowing in the spiral flow path between the inner pipe 1 and the insert body 2 and carbon dioxide flowing in the outer pipe 3 have opposite flow directions, the flow of the flow shown in FIGS. As described above, heat can be exchanged in a counter flow over substantially the entire area of the heat exchanger 11, and a highly efficient heat exchanger can be provided.

  It should be noted that even if all the parts of the outer tube 3 to be wound are not wound around the facing portion of the spiral flow path, it is sufficient if the heat exchange efficiency required by the mounted device is realized. In addition, a plurality of outer tubes 3 through which the second fluid flows may be provided, and the outer tubes 3 may be alternately wound around the facing portions of the spiral flow path.

  FIG. 3 is a cross-sectional view of heat exchanger 11 according to Embodiment 1 of the present invention. Since the water flow path of the heat exchanger is composed of two parts, the inner tube 1 and the insert body 2, the maximum distance from the water-side heat transfer surface is the diameter a of the insert body shaft portion 21 and the spiral protrusion 22. It can be designed based on the protrusion height th.

  In addition, the flow path cross-sectional area S can be designed by changing the winding pitch P of the spiral protrusion 22 of the insert body 2 so that the water pressure loss that can be allowed by the water transfer pump that transfers water in the device. As a result, the dead water area can be significantly reduced within the water pressure loss constraint range. Here, the diameter a of the insert shaft portion 21 and the projection height th of the spiral projection 22 are designed so that the heat exchange performance satisfies a predetermined performance within the range of the following (Equation 4). Is desirable.

  Further, in the first embodiment of the present invention, the flow passage cross section of the spiral flow passage that is the water flow passage is formed in a rectangular cross section by the inner surface of the inner pipe 1, the insert body shaft portion 21, and the spiral protrusion 22. As compared with the case where the cross section is circular, vortices are more likely to be generated, and the effect of the secondary flow is increased.

  As described above, in the first embodiment, the water flow path is configured by the two parts of the inner tube 1 and the insert 2 having the spiral protrusion 22, so that the inner tube 1 can be spirally wound without being wound. Forming a road. As a result, it is possible to provide a light-weight heat exchanger with the inner tube 1 having a minimum necessary wall thickness and excellent in economic efficiency.

  Further, since the curvature diameter D of the spiral flow path can be made significantly smaller than in the conventional case, it is possible to provide a compact heat exchanger having high heat transfer performance.

  In addition, the longest distance from the heat transfer surface of the water side flow passage can be designed by the diameter a of the insert shaft portion 21 and the height th of the protrusion of the spiral protrusion 22, and the flow passage cross-sectional area S is The winding pitch P of the spiral protrusion 22 can be changed and designed so that the loss is within the constraint. As a result, it is possible to provide a heat exchanger with high heat transfer performance in which the dead water area is significantly reduced within the restriction range of water pressure loss.

(Embodiment 2)
5A and 5B are enlarged views of the spiral protrusion 22 of the insert 2 of the heat exchanger 11 according to the second embodiment. 6A and 6B are cross-sectional views of the heat exchanger according to the same embodiment. FIG. 7 is a perspective view of a joint and an insert of the heat exchanger according to the same embodiment.

  The same parts as those of the first embodiment of the present invention are designated by the same reference numerals, and detailed description thereof will be omitted.

  As shown in FIG. 5B, on the outer surface of the spiral protrusion 22 of the insert 2 that constitutes the heat exchanger 11 of the second embodiment, the axial direction of the heat exchanger 11, that is, the axis of the insert 2 is formed. Protrusions 25 that are continuously arranged are provided along the direction. In addition, as shown in FIG. 7, the end of the insert 2 in the axial direction is a protrusion 23, and the joint 4 has a recess 24 that fits into the protrusion 23 of the end of the insert 2. ing.

  In the insert 2, the projection 23 on the axial end of the insert 2 and the recess 24 of the joint 4 are fitted together so that the projection 25 on the outer surface of the spiral projection 22 contacts the inner tube 1. It is fixed to.

  In addition, regarding the shape of the joint portion of the insert body 2 and the joint 4, although the convex portion and the concave portion are used in the second embodiment, any shape other than the joint portion may be used.

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

  In the present embodiment, since a gap is formed between the spiral projection 22 excluding the projection 25 and the inner pipe 1, in addition to the spiral flow passage described in the first embodiment, the heat exchanger A flow path (bypass flow path 50) communicating with the axial direction of 11, that is, the axial direction of the insert body 2 is formed.

  Similarly to the first embodiment, the heat exchanger 11 of the second embodiment also includes water, which is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert body 2, and the second fluid. The carbon dioxide flowing inside the outer tube 3 is a structure in which heat is exchanged with the opposite flow via the inner tube 1 and the outer tube 3.

  Here, when the temperature of the incoming water flowing into the heat exchanger 11 is high, the heated water may boil in the heat exchanger 11, so the flow rate of the water conveyed to the heat exchanger 11 is increased and the hot water is discharged. The temperature is adjusted so as to be equal to or lower than a predetermined temperature.

  However, in the conventional heat exchanger described in Patent Document 1, since the tube is wound to form the spiral flow path, the flow path length is longer than the linear flow path. Therefore, when the flow rate is large, the water pressure loss in the heat exchanger becomes large, so that the pump power of the device that conveys water becomes excessive and the energy saving of the device is impaired.

  In addition, when the water pressure loss in the heat exchanger 11 exceeds the transport capacity of the pump, the hot water outlet temperature cannot be kept below a predetermined temperature, and the reliability of the device is impaired. It was

  On the other hand, in the heat exchanger 11 according to the second embodiment, in addition to the spiral flow path, as shown in FIG. 6, the inner surface of the inner pipe 1 and the spiral protrusion 22 excluding the inner pipe 1 and the protrusions 25 are removed. And a bypass flow path 50 communicating with each other along the axial direction of the heat exchanger 11, that is, the axial direction of the insert body 2.

  Therefore, while stirring the flow by the secondary flow, when the centrifugal force acting on the water is large and the flow rate is large, the water flowing through the flow path communicating with the axial direction of the heat exchanger 11, that is, the axial direction of the insert body 2. Bypass amount increases.

  Therefore, an increase in pressure loss at the time of a large flow rate can be suppressed as compared with the conventional heat exchanger described in Patent Document 1 described above, and the power required by the transfer pump is reduced, so that the energy saving of the device is improved.

  In addition, since the increase in water pressure loss can be suppressed and the flow rate that can be carried by the pump of the same head is increased, it is possible to secure a sufficient flow rate to keep the temperature of discharged water flowing out below a predetermined temperature. Improves reliability.

  Further, the joint 4 is configured to be fitted to the insert body 2 and cover the inner pipe 1 from the outside with a fastening body such as the insertion pin 5 (see FIG. 1). The position of is fixed. As a result, in any installation state (vertical installation, horizontal installation, diagonal installation), the axial direction of the heat exchanger 11, that is, the axial direction of the insert 2 is provided between the spiral projection 22 and the inner tube 1. It is possible to secure a flow path communicating with each other.

  Therefore, it is possible to provide a heat exchanger with improved installation flexibility while suppressing an increase in pressure loss.

  As described above, in the second embodiment, the protrusions 25 that are continuously arranged along the axial direction of the heat exchanger 11 are provided on the outer surface of the spiral protrusion 22 of the insert body 2. The inner tube 1 and the insert 2 are fixed by a joint 4 so that the inner surface of the inner tube 1 contacts. Thereby, in addition to the spiral flow path, a flow path can be formed in the axial direction of the heat exchanger 11, so that even if the flow rate of the water flowing through the heat exchanger 11 is large, the heat loss that suppresses an increase in water pressure loss can be suppressed. A switch 11 can be provided. As a result, the energy saving property of the device equipped with the heat exchanger 11 according to the second embodiment is improved.

  Even if there is no protrusion 25, the joint 4 is fitted with the insert body 2 to cover the inner pipe 1 from the outside, and is fixed by the fastening body (see FIG. 5A). Also in (vertical installation, horizontal installation, diagonal installation), the flow path communicating between the spiral projection 22 and the inner tube 1 along the axial direction of the heat exchanger 11, that is, the axial direction of the insert 2 ( The bypass flow path 50) can be secured. Thus, by setting the distance between the spiral projection 22 and the inner pipe 1 at an appropriate distance, it is possible to provide the heat exchanger 11 with improved installation flexibility while suppressing an increase in water pressure loss.

(Embodiment 3)
FIG. 8 is a sectional view of the heat exchanger according to the third embodiment. The same parts as those of the first and second embodiments of the present invention are designated by the same reference numerals, and detailed description thereof will be omitted.

  The heat exchanger according to Embodiment 4 of the present invention is configured such that the relationship between the tip width t1 of the spiral protrusion 22 of the insert 2 and the root width t2 is t1 <t2.

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

  Similarly to Embodiments 1 and 2, the heat exchanger 11 according to Embodiment 4 also includes water, which is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert body 2, Carbon dioxide, which is the second fluid flowing inside the outer pipe 3, is heat-exchanged in a counterflow via the inner pipe 1 and the outer pipe 3.

  Water, which is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert 2, to carbon dioxide, which is the second fluid flowing inside the outer tube 3, of the heat exchanger 11. As shown in FIG. 8, the width L of the heat transfer surface is P-t1 obtained by subtracting the tip width t1 of the spiral projection 22 from the spiral pitch P of the spiral projection 22.

  In the present embodiment, as shown in FIG. 8, the shape of the spiral projection 22 of the insert 2 is configured so that t1 <t2. Thereby, as shown in FIG. 3 of the first embodiment, the spiral protrusion 22 has a constant thickness while maintaining the same water-side flow passage cross-sectional area S as in the case where the thickness of the spiral protrusion 22 is constant. Heat transfer of water, which is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert 2, to carbon dioxide, which is the second fluid flowing inside the outer tube 3, than in the case The width L of the surface can be increased.

  That is, the heat transfer area of water, which is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert 2, to carbon dioxide, which is the second fluid flowing inside the outer tube 3, Since it expands, a heat exchanger with higher heat exchange performance can be provided.

  FIG. 9 shows that the length of the spiral flow path formed between the inner pipe 1 and the insert 2 and the cross-sectional area S of the water-side flow path are constant, that is, the insert projection under the same water-side pressure loss condition. The relationship between the tip width t1 and the heat exchange capacity Q is shown.

  As can be seen from FIG. 9, the smaller the tip width t1 of the spiral projection 22, the more the carbon dioxide which is the second fluid flowing inside the outer tube 3 is formed between the inner tube 1 and the insert 2. The heat transfer area of water, which is the first fluid flowing through the spiral flow path, is expanded. This improves the heat exchange capacity.

Further, the root shape of the spiral protrusion 22 may be an R shape in order to suppress separation of the secondary flow at the root portion and reduce water side pressure loss. As a result, the friction loss of water due to the vortex can be reduced, so that the energy efficiency of the heat exchanger of the present embodiment and the equipment equipped with it can be improved.

  As described above, in the third embodiment, the relationship between the tip width t1 of the spiral projection 22 of the insert 2 and the root width t2 is configured to be t1 <t2. Thus, the water side flow path conditions (the length of the spiral flow path formed between the inner tube 1 and the insert 2 and the water side flow path cross-sectional area S) are not changed, that is, the water side pressure is It is the first fluid flowing through the spiral flow path formed between the inner tube 1 and the insert body 2 to carbon dioxide which is the second fluid flowing inside the outer tube 3 under the loss equal condition. The length of the water heat transfer surface can be increased. As a result, since the heat transfer area can be expanded, a heat exchanger with high heat exchange performance can be provided.

(Embodiment 4)
FIG. 10 is a configuration diagram of the refrigeration cycle device according to the fourth embodiment.

  The same components as those of the first to third embodiments of the present invention are designated by the same reference numerals and detailed description thereof will be omitted.

  FIG. 10 shows a refrigeration cycle device mounted on, for example, a heat pump water heater. The refrigeration cycle apparatus includes a compressor 101, a radiator 102 that is the heat exchanger 11 described in the first to third embodiments of the present invention, a decompression device 103 that is an electronic expansion valve, and an evaporator 104. To form the refrigerant circuit 105.

  The refrigerant circuit includes an evaporator outlet temperature detection unit 107 that detects the temperature of the refrigerant that has flowed out of the evaporator 104, and the refrigeration cycle apparatus includes a controller 110 and a defrosting operation mode.

  Carbon dioxide is enclosed as a refrigerant in the refrigerant circuit 105, and when the compressor 101 is operating, the high pressure side is operated in a supercritical state.

Further, the radiator 102 insert 2 having a helical projection 22 constituting the (heat exchanger 11 according to Embodiment 1 or Embodiment 2 of the present invention), large tree butter made of specific heat than metal it is.

  The operation and action of the refrigeration cycle apparatus configured as described above will be described below.

  When the compressor 101 is operated, the refrigerant that has been compressed to a high pressure and discharged is sent to the radiator 102 and exchanges heat with the low temperature water that has been sent by the water transport pump 113 through the water inlet pipe 111 to radiate heat. The low-temperature water thus heated becomes high-temperature water, passes through the hot water discharge pipe 112, is sent to a hot-water storage tank (not shown), and is stored as high-temperature hot water.

  The refrigerant flowing out from the radiator 102 is supplied to the decompression device 103, expanded under reduced pressure, sent to the evaporator 104, exchanges heat with the air introduced by the blower 106, and is evaporated and gasified. The gasified refrigerant is sucked into the compressor 101.

  Next, the defrosting operation operation of the heat pump water heater will be described.

  When the hot water storage operation is performed in a state where the outside air temperature is low, the evaporator 104 is frosted, and the heat exchange capacity of the evaporator 104 is significantly reduced.

  Therefore, the control device 110 performs a defrosting operation operation of defrosting the frost attached to the evaporator 104 and restoring the heat exchange capacity of the evaporator 104. The defrosting operation operation is executed when frost adheres to the evaporator 104 and the temperature detected by the evaporator outlet temperature detecting means 107 falls below a predetermined temperature. The defrosting operation operation will be specifically described below.

  First, the control device 110 stops the water transfer pump 113 that supplies water to the radiator 102 and the blower 106 to reduce the flow path resistance of the decompression device 103. The high-temperature refrigerant compressed by the compressor 101 passes through the radiator 102 and the pressure reducing device 103, flows into the evaporator 104, defrosts with the heat of the refrigerant, and is sucked into the compressor 101.

  Then, when the temperature detected by the evaporator outlet temperature detection means 107 exceeds a predetermined temperature, the defrosting operation operation ends and the boiling operation is performed.

  During this defrosting operation, in addition to the amount of heat of the refrigerant discharged from the compressor 101, the amount of heat stored in the radiator 102 is also utilized to defrost the evaporator 104.

By using the insert 2 which is a part of the flow path of the radiator 102 as a resin having a larger specific heat than metal, the heat storage amount of the radiator 102 is increased, and a larger amount of heat is released from the radiator 102 during defrosting. Available. As a result, the defrosting operation can be completed in a short time, and the defrosting performance of the device improves.

In addition, in the fourth embodiment of the present invention, the insert 2 having the spiral protrusion 22 is made of resin (PPS), but similar effects can be obtained if a resin other than PPS or a material having a large specific heat is used. Can be expected.

  In addition, in Embodiments 1 to 3 of the present invention, the refrigerant flowing through the outer tube 3 is carbon dioxide, but a hydrocarbon-based or HFC-based (R410A, etc.) refrigerant or an alternative refrigerant thereof is also the same. The effect can be expected.

  It should be noted that not only the respective embodiments described above but also combinations of all the above embodiments are within the scope of the present invention.

  INDUSTRIAL APPLICABILITY As described above, the heat exchanger according to the present invention can provide a heat exchanger that is compact, has excellent economical efficiency, and has high quality performance and high heat exchange performance. Therefore, the present invention can be applied to a device equipped with a heat exchanger that exchanges heat between fluids.

1 Inner tube 2 Insert body 3 Outer tube 4 Joint 5 Tomoewa (insertion pin)
11 Heat Exchanger 21 Insert Shaft Part 22 Spiral Protrusion 23 Protrusion 24 Concave 25 Protrusion 50 Bypass Flow Path 101 Compressor 102 Radiator 103 Pressure Reduction Device 104 Evaporator 105 Refrigerant Circuit

Claims (5)

At least a compressor, a heat exchanger, a pressure reducing device, and a refrigerant circuit in which an evaporator is annularly connected,
A control device,
A high-temperature refrigerant compressed by the compressor passes through the heat exchanger and the pressure reducing device, flows into the evaporator, melts frost on the evaporator, and is taken into the compressor in a defrosting operation mode. And
The heat exchanger includes an inner tube which water flows, and insert that is inserted into the inner tube, provided on an outer periphery of the inner tube, an outer tube in which the refrigerant flows, and
The insert includes a shaft portion and a spiral protrusion formed on an outer surface of the shaft portion,
The water is configured to flow in a spiral flow path formed by the inner surface of the inner pipe, the shaft portion and the spiral protrusion, and the water and the refrigerant flow in opposite directions .
During the defrosting operation mode, the flow of water in the heat exchanger is stopped,
The refrigerating cycle device, wherein the insert is made of resin . The refrigeration cycle apparatus according to claim 1, wherein the heat exchanger has a winding direction of the outer tube and a spiral direction of the spiral protrusion in the same direction. The refrigeration cycle apparatus according to claim 1 or 2, wherein in the heat exchanger, the outer pipe is arranged on an outer periphery of the inner pipe at a portion facing the spiral flow path. The heat exchanger, the inner tube, the refrigeration cycle apparatus according to any one of 請 Motomeko 1 to 3, further comprising a joint for fixing the insert, respectively. 5. The heat exchanger has a relationship of t1 <t2, where t1 is a tip width of the spiral protrusion and t2 is a root width of the spiral protrusion . Refrigeration cycle device .