JP2008122033A - Gas cooler for hot water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas cooler for a hot water supply system, which prevents scale clogging while maintaining heat exchange efficiency. <P>SOLUTION: The gas cooler for the hot water supply system is of the tube-in-tube type and comprises an inner conduit 28 through which a refrigerant of a heat pump unit flows, and an outer conduit 26 surrounding the inner conduit 28 and allowing a tank water of a hot water supply unit to flow through. The outer conduit 26 has a spiral groove 30 on its inner surface. The inner conduit 28 is formed of two inner tubes 32, and the inner tubes 32 extend in parallel with a space from each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas cooler incorporated in a hot water supply system including a heat pump unit.

  This type of hot water supply system is being promoted for the purpose of saving energy and reducing the burden on the global environment. The performance of a hot water supply system is evaluated by a coefficient of performance (COP), which greatly depends on the heat exchange efficiency in the gas cooler. That is, the gas cooler exchanges heat between the refrigerant on the heat pump unit side and the tank water on the hot water supply unit side, and thus is an important component for determining the performance of the hot water supply system.

In general, a tube-in-tube method is adopted for a gas cooler, and this tube-in-tube type gas cooler has an inner conduit for flowing refrigerant and an outer conduit for flowing tank water. In addition, it is also known that the outer pipe line is formed in a spiral shape, or a spiral partition is provided between the inner pipe line and the outer pipe line (for example, FIG. 1 and FIG. 9 of Patent Document 1). reference).
JP 2005-9832 A

The spiral outer pipe and partition of Patent Document 1 lengthen the tank water flow path that flows outside the inner pipe line, and also generate turbulence in the tank water flow so that the refrigerant and the tank water flow. It is expected to improve the heat exchange efficiency between the two.
However, since the water supply system uses tank water, when the tank water is heated to a high temperature in the gas cooler, the chlorinated components contained in the tank water scale, and the tank water flow path is clogged with scale. May occur.

In order to prevent such clogging of the scale, it is only necessary to increase the cross-sectional area of the tank water, that is, the inner diameter of the outer conduit. The ratio of tank water flowing in a layered manner along the inner surface of the tank increases, heat transfer from the refrigerant to the tank water deteriorates, and as a result, the heat exchange rate decreases.
The present invention has been made on the basis of the above-described circumstances, and its object is to provide hot water supply that can ensure a large passage cross-sectional area of tank water while maintaining heat exchange efficiency between the refrigerant and the tank water. It is to provide a gas cooler for the system.

  In order to achieve the above object, a gas cooler of a hot water supply system according to the present invention includes an inner pipe through which a refrigerant flows and an outer pipe that surrounds the inner pipe and forms a flow path through which the tank water flows outside the inner pipe. The outer pipe has a spiral groove on its inner surface along the inner pipe line and traveling in the direction of the tank water flow, and the inner pipe lines are spaced apart from each other to allow the tank water to pass therethrough. A plurality of inner tubes extending in parallel are included (claim 1).

When the tank water passes through the outer pipe, the tank water flows along the spiral groove, and a swirling flow of the tank water that swirls outside the inner pipe is generated in the outer pipe. Since the portion passes between the inner tubes of the inner conduit, the swirling flow is disturbed. Therefore, the tank water efficiently contacts the surface of the inner tube, and the surface heat transfer coefficient of the inner pipe line is improved.
Specifically, the refrigerant is CO ₂ gas (Claim 2), and such CO ₂ gas reduces the burden on the global environment.

  Preferably, the outer conduit includes a plurality of regions having different helical pitches (Claim 3), and each inner tube may have an uneven outer peripheral surface (Claim 4). Further, the uneven shape here is provided by spiral ridges extending along the outer peripheral surface of the inner tube (Claim 5), and in this case, the directions of the spirals of these ridges and spiral grooves are different from each other. (Claim 6).

  According to the gas cooler of claims 3 to 6, the flow of the tank water is further disturbed, and the surface heat transfer coefficient of the inner tube to the tank water is further improved.

The gas cooler according to claims 1 and 2 increases the surface heat transfer coefficient of the inner tube with respect to tank water because the spiral groove of the outer conduit and the plurality of inner tubes forming the inner conduit cooperate with each other. It is possible to increase the inner diameter of the outer pipe line while maintaining the heat exchange efficiency, and it is possible to reliably prevent clogging of the outer pipe line.
The gas cooler according to claims 3 to 6 further improves the heat exchange efficiency while preventing the clogging of the scale by further improving the surface heat transfer of the inner tube by further disturbing the flow of the tank water. Can do.

FIG. 1 schematically shows a hot water supply system.
The hot water supply system is roughly divided into a heat pump unit 2 and a hot water supply unit 4, and these units 2 and 4 are thermally connected to each other via a gas cooler 6.
More specifically, the heat pump unit 2 includes, for example, a refrigerant circulation path 8 through which a refrigerant of CO ₂ gas flows, and the refrigerant circulation path 8 includes an atmospheric heat exchanger 10 that performs heat exchange between the atmosphere and the refrigerant, a compression The machine 12, the gas cooler 6, the expansion valve 14 and the like are inserted.

On the other hand, the hot water supply unit 4 includes a hot water storage circulation path 16 through which tank water flows, and a gas cooler 6, a hot water storage tank 18, a circulation pump 20 and the like are interposed in the hot water storage circulation path 16, respectively. The hot water supply unit 4 also includes a water supply path 22 for supplying water to the hot water storage tank 18 and a hot water supply path 24 for supplying hot water from the hot water storage tank 18.
The gas cooler 6 is a tube-in-tube system, and forms a part of the hot water storage circulation path 16 as shown in FIG. 2, forms an outer conduit 26 through which tank water flows, and a part of the refrigerant circulation path 8, An inner conduit 28 that flows the refrigerant in a direction opposite to the tank water is provided, and the inner conduit 28 extends in the outer conduit 26.

In one embodiment, the inner surface of the outer conduit 26 is formed as a spiral groove 30, and the spiral groove 30 is set in the direction of the spiral so as to travel in the flow direction of the tang water in the outer conduit 26. Yes. Therefore, as indicated by an arrow A in FIG. 2, the tank water passing through the outer pipe 26 is guided along the spiral groove 30 to form a swirling flow that swirls outside the inner pipe 28. .
On the other hand, in the case of the present embodiment, the inner conduit 28 is composed of a plurality of, specifically, two copper inner tubes 32, and these inner tubes 32 extend in parallel with each other at a predetermined interval. Therefore, a space allowing passage of tank water is secured between the inner tubes 32, and the outer peripheral surfaces of the inner tubes 32 do not contact each other.

As shown in FIG. 3, each inner tube 32 has a double structure, and includes an inner pipe 34 through which a refrigerant flows and an outer pipe 36 as a leakage detection pipe surrounding the inner pipe 34. Therefore, even if the refrigerant leaks from the inner pipe 34, the leaked refrigerant is captured in the outer pipe 36, and the tank water in the outer pipe 26 is not contaminated by the refrigerant.
According to the gas cooler 6 described above, the tank water in the outer conduit 26 flows as a swirl flow swirling around the inner tube 32, and a part of the water passes through the space between the inner tubes 32 and scrapes the swirl flow. Disturb. Therefore, since the flow of the tank water collides with the outer peripheral surface of each inner tube 32 at an angle from the radial direction, the surface of the inner tube 32 with respect to the tank water can be satisfactorily brought into contact with the surface of each inner tube 32. Transmission can be effected effectively.

  Therefore, while maintaining the heat exchange efficiency of the gas cooler 6, the inner diameter of the outer pipe 26 can be increased, and a large channel cross-sectional wall for tank water can be secured. As a result, the tank water is heated to a high temperature in the gas cooler 6 due to heat exchange with the refrigerant, and even if the chlorinated component contained in the tank water is scaled in the outer pipeline 26, the outer pipeline 26 is clogged with scale. There is no such thing as causing it.

The present invention is not limited to one embodiment, and various modifications are possible.
The spiral groove 30 of the outer conduit 26 shown in FIG. 2 has a constant spiral pitch, but the spiral groove 30 of the outer conduit 26 shown in FIG. 4 has a spiral pitch (P1, P2). It contains several different areas. 4 is formed by a pair of inner tubes 40 having spiral ridges 38 on the outer peripheral surface thereof.

In this case, the direction of the spiral of the ridge 38 is preferably different from the direction of the spiral groove 30, and the ridge 38 of one inner tube 40 is in relation to the ridge 38 of the other inner tube 40. It is preferable that they extend half of the helical pitch and are shifted from each other.
Each of the above-described configurations complicates the internal shape of the outer pipe 26 and further disturbs the flow of tank water, thereby further improving the surface heat transfer of the inner tube 32 or 40. As a result, the outer pipe described above is obtained. The heat exchange efficiency of the gas cooler 6 can be further improved while preventing the clogging of the passage 26 from being scaled.

  In the above-described embodiment and modification, the inner conduit 28 is composed of two inner tubes, but there may be three or more inner tubes.

It is a schematic structure figure showing a hot-water supply system. It is the figure which showed a part of internal structure of the gas cooler of FIG. FIG. 3 is a cross-sectional view of the inner tube of FIG. 2. It is the figure which showed the outer side pipe line and the inner side pipe line of the modification.

Explanation of symbols

2 Heat pump unit 4 Hot water supply unit 6 Gas cooler 26 Outer conduit 28 Inner conduit 30 Spiral grooves 32, 40 Inner tube 38 Projection

Claims (6)

In the gas cooler of the hot water supply system that performs heat exchange between the refrigerant flowing through the refrigerant circulation path of the heat pump unit and the tank water flowing through the hot water storage circulation path of the hot water supply unit, and heating the tank water to a predetermined temperature,
The gas cooler is
An inner conduit through which the refrigerant flows;
An outer conduit that surrounds the inner conduit and forms a flow path for flowing the tank water outside the inner conduit;
The outer conduit has a spiral groove on its inner surface along the inner conduit and traveling in the tank water flow direction,
The gas cooler of a hot water supply system, wherein the inner conduit includes a plurality of inner tubes extending in parallel with each other to allow passage of the tank water. The gas cooler of a hot water supply system according to claim 1, wherein the refrigerant is CO ₂ gas.   The gas cooler of a hot water supply system according to claim 1 or 2, wherein the outer pipe line includes a plurality of regions having different helical pitches.   Each said inner tube has an uneven | corrugated outer peripheral surface, The gas cooler of the hot water supply system in any one of Claims 1-3 characterized by the above-mentioned.   The gas cooler for a hot water supply system according to claim 4, wherein the uneven shape is provided by a spiral protrusion extending along the outer peripheral surface of the inner tube.   The gas cooler of the hot water supply system according to claim 5, wherein directions of the spirals of the ridges and the spiral grooves are different from each other.

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