JPS62108971A - Heat exchanger for heat pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a heat exchanger in which a refrigerant flows through multiple passages,
In particular, it relates to a heat exchanger suitable for the outdoor side of a heat pump.

[Background of the invention]

Conventionally, this type of heat exchanger was disclosed in Japanese Patent Application Laid-Open No. 56-151861.
As described in , the refrigerant inlet and outlet of each passage enter from the bottom and exit from the top. Alternatively, the refrigerant inflow direction was the same for the multiple passages in which the refrigerant flows in from the top and flows out from the bottom. In such a heat exchange Z;, when defrosting is carried out by flowing the refrigerant from the bottom to the top in each passage, the high temperature refrigerant enters the heat exchanger 7) from a place away from the upper end side, and the high temperature refrigerant enters the heat exchanger 7) from a place far from the upper end side, and the refrigerant enters the heat exchanger 7) from a place far from the upper end. , the refrigerant flows into the end side passage. When this refrigerant is flowing through the end side passage, in addition to the heat for defrosting, it requires thermal energy to cover the escape of heat from the end face, but because the temperature is low, the refrigerant does not have enough energy. The amount of heat cannot be secured, which may result in defrosting failure.

[Purpose of the invention]

An object of the present invention is to provide a heat exchanger suitable for defrosting in a heat pump air conditioner.

[Summary of the invention]

Heat exchangers are generally divided into multiple passages and V-sections in order to reduce the flow resistance of the refrigerant. At this time, when used as an evaporator, the refrigerant flows into each passage from the bottom and flows out from the top to prevent the refrigerant from returning.

Further, when used as a condenser, each passage enters from the upper part and exits from the lower part 7 to promote condensation.

When such a heat exchanger is used as an outdoor heat exchanger for a heat pump, frost may form on the heat exchanger, so a defrosting operation is required to remove this. During this 1/2 operation, frost adhering to the uppermost channel or the lowermost channel of the heat exchanger may melt and leave some residue. Focusing on this point, the present invention aims to facilitate unboxing by flowing refrigerant from the passages on the upper and lower end surfaces of the 7 heat exchanger, and supplying high-temperature refrigerant to the pipes on the end surface side where there is a lot of heat leakage. Features.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The heat exchanger shown in Fig. 1 consists of heat exchanger tubes 1 and fins 2, and a distributor 3 and a header 4 for distributing or collecting refrigerant flowing into the heat exchanger into each passage. Pipes 5a, 5a, 7a at the entrance and exit of the passage
And contact with 5b, 6b, 7b! has been done. This heat exchanger is an embodiment of a heat pump air conditioner in which refrigerant flows in from the distributor 3 side and flows out to the header 4 side during defrosting operation. Distributor-3
The refrigerant flowing into the heat exchanger is distributed to flow into the heat exchanger fins and flows into the heat exchanger through each passage inlet pipe 5a, 5a, 7a. Here, the refrigerant heats and melts the frost via a heat exchanger. Thereafter, it flows out from each passage and is collected in the header 4. Generally, an outdoor heat exchanger for a heat pump air conditioner has a bottom plate, a top plate, etc. at the lower and upper portions, and these plates are in contact with the upper and lower end surfaces of the heat exchanger fins. For this reason, in the case of a conventional configuration in which refrigerant enters each passage from the bottom, heat is transferred from the refrigerant to the upper plate in the uppermost passage, and the refrigerant temperature at the refrigerant outlet side is lower than that at the inlet side. , it is difficult to melt the box that has formed frost near the upper flow path of the uppermost passage. In this heat exchanger, the refrigerant inlet of the top passage was reversed with the refrigerant population of the lower passage.

That is, the refrigerant was allowed to flow in from above only at the top.

As a result, high-temperature refrigerant flows into the upper flow path of the uppermost passage, so defrosting failure does not occur.

The heat exchanger shown in FIG. 2 is an embodiment in which refrigerant flows into the heat exchanger from the header 4 side and flows out to the distributor 3 side during defrosting operation.

This heat exchanger has a structure in which refrigerant flows into only the lowermost passage from below and flows out from above. In the lower passage vc of the lowest passage where heat is easily dissipated to the bottom plate, high temperature refrigerant flows, so defrosting failure does not occur.

As described above, in the heat exchanger of the present invention, during unboxing operation, the refrigerant flows through the uppermost and lowermost passages, respectively.
The structure is such that the flow flows from the upper plate side and the bottom plate side), and
Since the high temperature refrigerant flows through difficult-to-clean areas, no removal defects occur.

〔Effect of the invention〕

As explained above, according to the present invention, in the defrosting operation for removing the box attached to the outdoor heat exchanger during the heating operation of the heat pump air conditioner, parts that are difficult to defrost (the upper part of the heat exchanger Lower part) VC High-temperature refrigerant can be flowed, improving LM% removal and shortening defrosting time. Furthermore, since the thermal energy required for defrosting can be reduced, it is also effective in saving energy in the air conditioner.

[Brief explanation of drawings]

FIG. 1 is a front view of a heat exchanger showing one embodiment of the present invention, and FIG. 2 is a front view of a heat exchanger showing another embodiment. 1... Heat exchanger tube 2... Fin 3... Dis) IJ computer 4... Header 5a...
Refrigerant inlet pipe in the top passage 5b... Refrigerant outlet pipe in the top passage 6a... Refrigerant inlet pipe in the bottom passage 6b.
...Refrigerant outlet pipe in the bottom passage. 〆. ＼、

Claims (1)

[Claims] A heat pump air conditioner whose refrigeration cycle consists of a compressor, four-way valve, indoor heat exchanger, expansion device, and outdoor heat exchanger.
In a heat exchanger in which each path is divided in the vertical direction of the unit, the relationship between the inlet and outlet of each path is such that during defrosting, the pipes at both the upper and lower ends of the unit become inlets. exchanger.