Heat transfer tube and heat exchanger using same

Abstract

The invention provides a heat transfer tube for a heat exchanger and the heat exchanger using the heat transfer tube. The heat transfer property of the heat exchanger can be improved even in such a usage mode as a small flow is in a heat pump type water heater. The heat exchanger (100) consists of the corrugated heat transfer tube (10); and an outer tube (11), which is arranged outside the corrugated heat transfer tube (10). When the depth of a corrugated groove is set to be Hc, and the outer diameter of the corrugation is set to be OD, the ratio of Hc to OD is more than or equal to 0.04. When the angle formed by the corrugated groove and the axis of the tube (Ta) is a distorted angle Beta c, Beta c is more than or equal to 40 degrees.

Description

technical field [0001] The present invention relates to heat transfer tubes for heat exchangers and heat exchangers using the same, and more particularly to heat transfer tubes for water-refrigerant heat exchangers of natural refrigerant heat pump water heaters (hereinafter, sometimes simply referred to as "heat pump water heaters") and Use its heat exchanger. Background technique [0002] For a long time, in heat pump water heaters using known natural refrigerants (for example, carbon dioxide refrigerants), two heat exchangers, radiators and heat absorbers, are generally used. As the heat transfer tubes used in these heat exchangers, radiators are used. Refrigerant pipes for heaters and refrigerant pipes for heat sinks. [0003] In addition, in this heat pump water heater, the radiator is also called a water-refrigerant heat exchanger, and not only the above two heat transfer tubes are used, but also other heat transfer tubes that exchange with the refrigerant (water tubes...

AI Technical Summary

Problems solved by technology

[0008] However, in the heat exchanger described in Patent Document 1, there is a problem that the process of twisting a plurality of heat transfer tubes into a spiral shape itself is complicated and increases cost (the process of twisting a hollow tube that is prone to deformation such as crushing or bending) It is not as easy as the process of twisting a solid metal wire), and the processing (structure) of the end part of the heat exchanger separating the first heat transfer tube and the second heat transfer tube becomes complicated

In addition, there is also the following problem: when the above-mentioned leak detection part is installed, each second heat transfer tube must be made into a double tube, etc., which further causes high cost.

[0009] In addition, in the heat exchanger described in Patent Document 2, even if the core tube is simply formed into a corrugated shape and a twisted plate is inserted into the core tube, the desired heat transfer performance cannot be obtained, which may lead to an increase in cost or pressure loss. Happening

In addition, when the core tube is made as a tube with grooves on the inner surface, even if the heat transfer area is increased, the effect of increasing the heat transfer area cannot be obtained in the laminar flow region where the flow velocity is small.

In addition, since the pipe with grooves on the inner surface is restricted by the manufacturing method, it is difficult to form a large shape change that causes turbulent flow in the laminar flow region with low flow velocity.

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