JP2016205764A - Heat exchanger and heat pump water heater using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger which can suppress increase in pressure loss of water, and which can increase energy efficiency of the entire equipment loading it.SOLUTION: A heat exchanger includes: an inner pipe 2 in which a first fluid flows; an insertion body 3 inserted in the inner pipe 2; and at least one or more outer pipes 4 which are provided on an outer periphery of the inner pipe 2, and in which a second fluid flows. The insertion body 3 includes a shaft part 5 and a spiral projection 6 formed on an outside surface of the shaft part 5. The first fluid flows in a spiral flow passage 7 formed by an inner surface of the inner pipe 2, the shaft part 5 and the spiral projection 6, and a spiral groove 8 is provided on the inner surface of the inner pipe 2 in the heat exchanger. The heat exchanger can be provided which can suppress increase in pressure loss of water, and which improves energy efficiency of the entire equipment loading it.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, this type of heat exchanger has a water flow path formed therein, spirally wound in a substantially cylindrical shape, and spirally wound at a predetermined pitch around the outer periphery of the substantially cylindrical water tube. And a refrigerant pipe having a refrigerant flow path formed therein, and heat exchange is performed between the refrigerant and water by closely contacting the refrigerant pipe and the water medium pipe (see, for example, Patent Document 1). .

  FIG. 4 shows a conventional heat exchanger described in Patent Document 1, and is a perspective view in which a part of the heat exchanger is cut out and a part thereof is cut out.

  The heat exchanger 101 includes a water tube 102 spirally wound in a substantially cylindrical shape, and a refrigerant tube 103 spirally wound in a substantially cylindrical shape on the outer periphery of the water tube 102 at a predetermined pitch. The refrigerant pipe 103 is joined over substantially the entire length of the water pipe 102, and the flow direction of the water flowing inside the water pipe 102 and the flow direction of the refrigerant flowing inside the refrigerant pipe 103 are opposed to each other.

  In addition, a plurality of grooves 104 and a plurality of fins 105 positioned between the plurality of grooves 104 are provided on the inner peripheral surface of the water pipe 102 to increase the heat transfer area for heat exchange with water. The heat exchange efficiency of the exchanger 101 is improved.

Japanese Patent No. 5289088

  However, in the conventional configuration, since the outer peripheral surface of the water tube 102 wound in a substantially cylindrical shape is in contact with the refrigerant tube 103, the heat of the refrigerant is easily transferred to water, while the inner peripheral surface of the water tube 102 is Since it is not in contact with the refrigerant pipe 103, heat from the refrigerant is hardly transmitted.

  Therefore, even if the plurality of fins 105 are provided in the pipe of the water pipe 102, the heat transfer from the refrigerant to the water is not promoted so much on the inner peripheral surface of the water pipe 102 wound in a substantially cylindrical shape. Only the pressure loss of water due to water increases.

  For this reason, even if the inner grooved pipe is applied to the water pipe 102 and the cost and material are added to improve the single heat exchange efficiency of the heat exchanger 101, the equipment for transporting water to the heat exchanger 101 is used. Since the power of the water conveyance pump mounted on the vehicle increases more than necessary, there is a problem that the energy efficiency of the entire device cannot be expected to increase.

  This invention solves the said conventional subject, and it aims at providing the heat exchanger which can suppress the increase in the pressure loss of water and improves the energy efficiency of the whole mounted apparatus.

In order to solve the conventional problem, a heat exchanger according to the present invention is provided with an inner pipe through which a first fluid flows, an insert inserted into the inner pipe, an outer periphery of the inner pipe, and a second fluid. At least one outer tube through which the fluid flows, and the insert includes a shaft portion and a spiral protrusion formed on the outer surface of the shaft portion, and the first fluid is an inner surface of the inner tube. And a spiral groove formed on the inner surface of the inner tube, while flowing through a spiral flow path formed by the shaft portion and the spiral protrusion.

  As a result, a spiral flow path through which water flows is constituted by two parts of an inner tube having a spiral groove on the inner surface and in direct contact with the outer tube and an insert not in contact with the outer tube. Only the inner pipe that directly contributes to heat transfer can be expanded while maintaining the heat transfer promotion effect of the swirl flow and secondary flow. While suppressing the pressure loss of water, the heat transfer can be promoted by the spiral groove.

  ADVANTAGE OF THE INVENTION According to this invention, the increase in the pressure loss of water can be suppressed and the heat exchanger which improves the energy efficiency of the whole mounted apparatus can be provided.

Schematic of the heat exchanger in Embodiment 1 of the present invention (A) Cross-sectional view of the heat exchanger when the spiral direction of the spiral protrusion of the heat exchanger and the spiral direction of the spiral groove are opposite directions (b) of the heat exchanger according to Embodiment 1 of the present invention Sectional drawing when the spiral direction of the spiral protrusion and the spiral direction of the spiral groove are the same direction Sectional drawing of the other heat exchanger in Embodiment 1 of this invention A perspective view of a conventional heat exchanger

  The first invention includes an inner tube through which the first fluid flows, an insert inserted into the inner tube, and at least one or more outer tubes provided on the outer periphery of the inner tube through which the second fluid flows. The insert includes a shaft portion and a spiral protrusion formed on the outer surface of the shaft portion, and the first fluid is formed by the inner surface of the inner tube, the shaft portion, and the spiral protrusion. The heat exchanger is characterized in that a spiral groove is provided on the inner surface of the inner tube while flowing through the formed spiral channel.

  As a result, a spiral flow path through which water flows is constituted by two parts of an inner tube having a spiral groove on the inner surface and in direct contact with the outer tube and an insert not in contact with the outer tube. Only the inner pipe that directly contributes to heat transfer can be expanded while maintaining the heat transfer promotion effect of the swirl flow and secondary flow. While suppressing the pressure loss of water, the heat transfer can be promoted by the spiral groove.

  The second invention is a heat exchanger characterized in that, in the first invention in particular, the spiral direction of the spiral protrusion and the spiral direction of the spiral groove are the same direction.

  Thereby, since the clearance gap produced between the front end surface of a spiral protrusion and a spiral groove can be made small, the clearance gap between an insertion body and the inner surface of an inner tube can be made as small as possible, and it does not contribute to heat transfer. The flow of water in the axial direction of the inner pipe can be reduced, and the heat exchange efficiency can be increased.

  The third invention is a heat exchanger characterized in that, in particular, in the first or second invention, the tip surface of the spiral projection covers the opening of a part of the spiral groove.

  As a result, the gap between the insert and the inner surface of the inner tube can be made as small as possible, so the flow of water in the axial direction of the inner tube that does not contribute to heat transfer can be reduced, and the heat exchange efficiency can be increased. Can do.

A fourth invention is a heat pump water heater equipped with the heat exchanger according to any one of the first to third inventions, and can improve the energy efficiency of the 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 schematic view in which a part of the heat exchanger according to Embodiment 1 of the present invention is cut away.

  FIG. 2A is a cross-sectional view of the heat exchanger when the spiral direction of the spiral protrusion 6 and the spiral direction of the spiral groove 8 are opposite to each other.

  Moreover, FIG.2 (b) is a heat exchanger in the heat exchanger in Embodiment 1 of this invention in case the spiral direction of the helical protrusion 6 and the spiral direction of the spiral groove 8 are the same direction. It is sectional drawing.

  FIG. 3 is a cross-sectional view of the heat exchanger showing a configuration in which the protrusion 10 formed at the tip of the spiral protrusion 6 of the insert 3 is shaped to fit into the spiral groove 8 of the inner tube 2. .

  Hereinafter, based on each drawing, the heat exchanger in Embodiment 1 of this invention is demonstrated.

  In FIG. 1, a heat exchanger 1 includes an inner tube 2 through which water as a first fluid flows, an insert 3 inserted into the inner tube 2, and a refrigerant (for example, a second fluid inside). Carbon dioxide) and at least one or more outer pipes 4 closely contacting the outer circumference of the inner pipe 2, which exchanges heat by flowing water and refrigerant in opposite directions. None).

  The insert 3 is formed from a shaft portion 5 and a spiral protrusion 6 spirally provided on the outer periphery of the shaft portion 5, and is disposed between the inner tube 2 and the inner surface of the inner tube 2 and the shaft portion 5. An annular and spiral spiral channel 7 is formed, which is formed by the outer surface and the adjacent spiral protrusion 6.

  A plurality of spiral grooves 8 and a plurality of standing walls 9 that form the spiral grooves 8 are provided on the inner surface of the inner tube 2 to increase the heat transfer area for heat exchange with water.

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

  The heat exchanger 1 exchanges heat by flowing a high-temperature refrigerant flowing inside the outer tube 4 and a low-temperature water flowing through a spiral flow path 7 disposed between the inner tube 2 and the insert 3 to face each other. And when it mounts in a heat pump type hot water heater, the hot water for hot water supply is produced | generated.

  Here, since the water flows through the spiral flow path 7 along the spiral protrusion 6 provided in a spiral shape, the heat pump water heater is provided by the swirl flow by the spiral and the secondary flow effect by the cross section of the rectangular flow path of the water. Thus, even when the flow rate of water is low, the heat exchange efficiency can be improved.

  Further, the inner tube 2 that has the spiral groove 8 on the inner surface and is in close contact with the outer tube 4, and the insert 3 that is not provided with the spiral groove 8 on the outer surface and is not in close contact with the outer tube 4. Since the spiral flow path 7 through which water flows is formed, only the inside of the inner pipe 2 that directly contributes to heat transfer is transmitted while maintaining the heat transfer promotion effect of the swirl flow and the secondary flow of the spiral flow path 7. The thermal area can be enlarged.

  For this reason, the heat transfer promotion of the water by the spiral groove 8 can be aimed at, suppressing the increase in the pressure loss of the water in the insertion body 3 which is not accompanied by the movement of heat.

  As described above, in the spiral flow path 7 of the present invention, the spiral groove 8 can be provided only in a portion that contributes to heat transfer, so that the heat exchange efficiency is improved and at the same time an increase in water pressure loss is suppressed. it can.

  For this reason, in a heat pump water heater, since it becomes possible to suppress a raise of water conveyance pump power, the energy efficiency of the whole heat pump water heater can be improved.

  On the other hand, as shown in FIG. 2 (a), the spiral direction of the spiral protrusion 6 of the insert 3 is the clockwise direction, and a plurality of spiral grooves 8 provided on the inner surface of the inner tube 2, that is, the spiral When the spiral directions of the adjacent standing walls 9 forming the groove 8 are counterclockwise, the spiral directions of the two are different, so that water flows between the spiral protrusion 6 and the spiral groove 8. The spiral flow of water along the spiral protrusion 6 of the insert 3 is weakened, and the heat transfer promotion effect by the swirling flow is reduced.

  Therefore, as shown in FIG. 2B, the spiral direction of the spiral protrusion 6 of the insert 3 and the plurality of spiral grooves 8 provided on the inner surface of the inner tube 2, that is, adjacent to each other to form the spiral grooves 8. By making the spiral directions of the plurality of standing walls 9 the same (for example, both clockwise), the flow of water passing between the spiral protrusion 6 and the spiral groove 8 can be reduced, and heat transfer by the swirl flow The promoting effect can be improved as compared with the case of FIG.

  Note that it is preferable that the width S of the spiral protrusions 6 is larger than the pitch P of the spiral grooves 8 because the flow of water across the spiral protrusions 6 can be further reduced.

  Further, as shown in FIG. 3, the tip surface of the spiral protrusion 6 of the insert 3 is formed at the tip of the spiral protrusion 6 of the insert 3 so as to cover the opening of a part of the spiral groove 8. By fitting the protrusion 10 into the spiral groove 8, the gap between the spiral protrusion 6 and the spiral groove 8 can be made as small as possible, and the heat transfer enhancement effect by the swirling flow can be maintained.

  Moreover, the outer diameter dimension of the insertion body 3 can be enlarged by making the height of the standing wall 9 forming the spiral groove 8 smaller than the root width of the standing wall 9. For this reason, the effect of the swirling flow effect of the water spiral channel 7 can be promoted and heat transfer can be facilitated.

  In the first embodiment of the present invention, the number of outer tubes 4 is one, but the same effect can be expected even when the number of outer tubes 4 is larger.

  In Embodiment 1 of the present invention, carbon dioxide is used as an example of the refrigerant flowing in the outer tube 4, but it is assumed that the refrigerant is a hydrocarbon type or HFC type (R410A, R32, etc.), or an alternative refrigerant thereof. The same effect can be expected.

  As described above, the heat exchanger according to the present invention is compact and economical, and can provide a heat exchanger with high quality performance and heat exchange performance. Therefore, a heat exchanger that performs heat exchange between fluids is mounted. Applicable to equipment.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Inner tube 3 Insert 4 Outer tube 5 Shaft part 6 Spiral protrusion 7 Spiral flow path 8 Spiral groove 9 Standing wall 10 Protrusion S Spiral protrusion width P Spiral groove pitch

Claims (4)

An inner pipe through which the first fluid flows;
An insert inserted into the inner tube;
At least one outer tube provided on the outer periphery of the inner tube and through which the second fluid flows;
With
The insert includes a shaft portion and a spiral protrusion formed on the outer surface of the shaft portion,
The first fluid flows through a spiral flow path formed by the inner surface of the inner tube, the shaft portion, and the spiral protrusion,
A heat exchanger characterized in that a spiral groove is provided on the inner surface of the inner tube. The heat exchanger according to claim 1, wherein the spiral direction of the spiral protrusion and the spiral direction of the spiral groove are the same direction. The heat exchanger according to claim 1 or 2, wherein a tip surface of the spiral protrusion covers a part of the opening of the spiral groove. A heat pump water heater equipped with the heat exchanger according to any one of claims 1 to 3.

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