JP2012042125A - Heat exchanger for hot water supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive heat exchanger for hot water supply which exhibits high heat efficiency and prevents a refrigerant from being mixed in water supply.SOLUTION: The heat exchanger 7 for hot water supply includes a refrigerant pipe 72, in which a refrigerant for heating flows, and which is arranged in a water flow passage 71 for distributing water to be heated for hot water supply. Material used for an outer surface of the refrigerant pipe 72 exhibits higher corrosion resistance than that of an inner surface of the water flow passage 71, and the water flow passage 71 and the refrigerant pipe 72 are formed of copper or copper alloy. A plated layer 73 is formed on the outer surface of the refrigerant pipe 72, and the corrosion resistance of the outer surface of the refrigerant pipe 72 is increased than that of the water flow passage 71.

Description

  The present invention relates to a heat exchanger for hot water supply used for a heat pump type hot water heater for heating water for hot water supply using a refrigerant having a high temperature and a high pressure by a heat pump.

  Conventionally, in a heat exchanger for hot water supply of this type of heat pump type hot water heater, a refrigerant pipe through which refrigerant flows is arranged in a water pipe through which water for hot water supply flows, and the refrigerant pipe is connected to the refrigerant inner pipe and the refrigerant outer pipe. As a double pipe composed of the above, a leak detection groove is provided between the refrigerant inner pipe and the refrigerant outer pipe so that when refrigerant or water leaks, the occurrence of leakage can be detected outside through the leak detection groove There was a thing.

JP 2005-69620 A

  However, in this conventional one, since the leakage detection groove is provided between the refrigerant inner pipe and the refrigerant outer pipe, the thermal efficiency is low, and a corresponding thickness is required for each of the refrigerant inner pipe and the refrigerant outer pipe. Therefore, it was a factor of cost increase.

  However, when the refrigerant pipe is composed of a single pipe, the outer surface of the refrigerant pipe and the inner surface of the water pipe are both in contact with the flowing water, so it is accidental on which surface erosion or pitting occurs. When the refrigerant pipe is eroded and there is a hole, there is a possibility that the refrigerant or the refrigerating machine oil may be mixed into the hot water supply water.

  In view of the above, an object of the present invention is to provide a hot water supply heat exchanger that has high thermal efficiency and does not cause a refrigerant to be mixed into the water supply at a low cost.

  In order to achieve the above object, the present invention provides a hot water supply heat exchanger in which a refrigerant pipe through which a heating refrigerant flows is arranged in a water flow path through which heated water for hot water supply circulates, and the water flow is provided on an outer surface of the refrigerant pipe. A material having higher corrosion resistance than that of the inner surface of the road was used.

  In addition, the water flow path and the refrigerant pipe are formed of copper or a copper alloy, and a plating layer is formed on the outer surface of the refrigerant pipe so that the corrosion resistance of the outer surface of the refrigerant pipe is higher than that of the water flow path. .

  Further, the water flow path is made of phosphorous deoxidized copper, the refrigerant pipe is made of high-strength copper, and the corrosion resistance of the outer surface of the refrigerant pipe is made higher than that of the water flow path.

  Further, the water flow path is formed of copper or a copper alloy, and the refrigerant pipe is formed of stainless steel so that the corrosion resistance of the outer surface of the refrigerant pipe is higher than that of the water flow path.

  According to the present invention, since the corrosion resistance of the outer surface of the refrigerant pipe is higher than the corrosion resistance of the inner surface of the water flow path, the outer surface of the refrigerant pipe and the inner surface of the water flow path are similarly eroded by the flow of hot water supply water. The inner surface of the water flow path is likely to be eroded first, even in an environment where there is little damage to the refrigerant pipe, and the water flow path breaks, so there is no risk of refrigerant entering the hot water supply and excellent thermal efficiency A hot water supply heat exchanger can be provided at low cost.

The schematic block diagram of the heat pump type water heater using the heat exchanger for hot water supply of this invention. The perspective view of the heat exchanger for hot water supply of this invention. The principal part sectional drawing of the heat exchanger for hot water supply of 1st Embodiment. The principal part sectional drawing of the heat exchanger for hot water supply of 2nd, 3rd embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a heat pump type hot water heater using a heat exchanger for hot water supply according to the present invention. 1 is a hot water storage tank for storing hot water for hot water supply, and 2 is connected to the bottom of the hot water storage tank 1 to supply city water. A water supply pipe 3 is connected to the top of the hot water storage tank 1 to discharge hot water, 4 is a circulation circuit for returning hot water taken out from the lower part of the hot water storage tank 1 to the upper part of the hot water storage tank 1, and 5 is provided in the circulation circuit 4. Circulation pump.

  6 is a compressor that compresses the refrigerant, 7 is a heat exchanger for hot water supply that is provided in the circulation circuit 4 and exchanges heat between the hot water and the refrigerant, and 8 is an electronic expansion valve that serves as a decompression unit that decompresses the refrigerant after heat dissipation, 9 is an air heat exchanger as an evaporator for evaporating a low-temperature and low-pressure refrigerant, 10 is a blowing means for blowing outside air to the air heat exchanger 9, 11 is a compressor 6, a hot water supply heat exchanger 7, and an electronic expansion valve 8 This is a heat pump circuit in which the air heat exchanger 9 is annularly connected by a refrigerant pipe 12. The heat pump circuit 11 uses carbon dioxide as a refrigerant and is designed to be in a supercritical state on the high pressure side.

  When boiling the hot water, heat is exchanged with hot water in the hot water storage tank 1 in which the refrigerant compressed to a high temperature and high pressure by the compressor 6 is circulated to the water side circuit of the hot water supply heat exchanger 7, and the heated hot water is Hot water is stored in the hot water storage tank 1 and is pushed out from the hot water discharge pipe 3 by hot water pressure from the water supply pipe 2 when hot water is supplied.

  Here, as shown in FIG. 2, the hot water supply heat exchanger 7 has a double pipe in which a refrigerant pipe 72 in which a heating refrigerant flows is arranged in a tubular water flow path 71 through which hot water for hot water flows. It is configured to be wound around.

  FIG. 3 is a cross-sectional view of the first embodiment of the hot water supply heat exchanger 7. The water flow path 71 and the refrigerant pipe 72 are made of copper or a copper alloy, and the refrigerant pipe 72 through which the refrigerant flows is formed on the outer surface of the refrigerant pipe 72. A plating layer 73 is formed. Here, the plating layer may be any of tin plating, chromium plating, zinc plating, and nickel plating, but tin plating is more preferable.

  Thus, since the plating layer 73 is formed only on the outer surface of the refrigerant pipe 72 through which the refrigerant flows, and the corrosion resistance of the outer surface of the refrigerant pipe 72 is higher than that of the inner surface of the water flow path 71, Even in an environment where the surface (plating layer 73) and the inner surface (copper or copper alloy) of the water flow channel 71 are similarly eroded by the flow of hot water supply water, the inner surface of the water flow channel 71 is likely to be eroded first. Since the pipe 72 is less damaged and crushed and pitting corrosion occurs in the water flow path 71, there is little possibility of refrigerant mixing into the hot water supply water, and the hot water supply heat exchanger 7 having excellent thermal efficiency can be inexpensive. Can be provided.

  FIG. 4 is a cross-sectional view of the second embodiment, in which the water channel 71 is made of phosphorous deoxidized copper, and the refrigerant pipe 72 is made of high-strength copper. Here, phosphorus deoxidized copper and high-strength copper are those defined by JIS H 3300.

  Thus, since the refrigerant pipe 72 in which the refrigerant flows is formed of a material having higher corrosion resistance than the material of the water flow path 71, the outer surface (high strength copper) of the refrigerant pipe 72 and the inner surface of the water flow path 71 ( Even in an environment in which (phosphorus deoxidized copper) is similarly eroded by the flow of hot water, the inner surface of the water flow path 71 is likely to be eroded first, and the water flow path 71 is eroded while the refrigerant pipe 72 is less damaged. Moreover, since pitting corrosion occurs and breaks, there is little possibility that the refrigerant is mixed into the hot water supply water, and the hot water supply heat exchanger 7 excellent in thermal efficiency can be provided at low cost.

  In the third embodiment, the water flow path 71 is made of copper or a copper alloy, and the refrigerant pipe 72 is made of stainless steel.

  In this way, the refrigerant pipe 72 through which the refrigerant flows is formed of a material having higher corrosion resistance than the material of the water channel 71, so that the outer surface (stainless steel) of the refrigerant tube 72 and the inner surface of the water channel 71 (copper or copper) Even in an environment where the alloy) is similarly eroded by the flow of hot water, the inner surface of the water channel 71 is likely to be eroded first, and the water channel 71 is eroded and pitted while the refrigerant pipe 72 is less damaged. Therefore, it is possible to provide the hot water supply heat exchanger 7 with excellent thermal efficiency at low cost.

  The present invention is not limited to the above-described embodiment. For example, a box-shaped water channel may be used, and a plurality of refrigerant tubes are arranged in the water channel, or a refrigerant other than carbon dioxide is used as the refrigerant. May be used.

7 Heat exchanger 71 for hot water supply Water flow path 72 Refrigerant pipe 73 Plating layer

Claims (4)

  In a hot water supply heat exchanger in which a refrigerant pipe through which a heating refrigerant flows is arranged in a water flow path through which heated water for hot water supply circulates, the corrosion resistance higher than the corrosion resistance of the inner surface of the water flow path on the outer surface of the refrigerant pipe A heat exchanger for hot water supply, characterized by using a material having the above.   The water flow path and the refrigerant pipe are formed of copper or a copper alloy, and a plating layer is formed on the outer surface of the refrigerant pipe so that the corrosion resistance of the outer surface of the refrigerant pipe is higher than that of the water flow path. The heat exchanger for hot water supply according to claim 1 characterized by the above-mentioned.   2. The water channel is formed of phosphorous deoxidized copper, the refrigerant pipe is formed of high-strength copper, and the corrosion resistance of the outer surface of the refrigerant pipe is higher than that of the water channel. Heat exchanger for hot water supply.   The said water flow path is formed with copper or a copper alloy, and the said refrigerant | coolant pipe | tube is formed with stainless steel, The corrosion resistance of the outer surface of the said refrigerant | coolant pipe | tube is improved rather than the said water flow path. Heat exchanger for hot water supply.

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