Double-wall-tube heat exchanger

Abstract

A double-wall-tube heat exchanger has an outer tube, and an inner tube disposed concentrically in and spaced apart from the outer tube. A clearance between the outer tube and the inner tube and the interior of the inner tube serve as respective refrigerant flow paths. The inner tube has a plurality of interior fins formed on its inner circumferential surface. The interior fins project radially inward; extend in a longitudinal direction of the inner tube; and are arranged at circumferential intervals. The inner tube has a plurality of elongated projections formed on its outer circumferential surface. The elongated projections project radially outward; extend in the longitudinal direction; and are arranged at circumferential intervals. The interior fins are greater in height than the elongated projections. The double-wall-tube heat exchanger exhibits excellent heat exchange performance.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a double-wall-tube heat exchanger and, more particularly, to a double-wall-tube heat exchanger which has an outer tube, and an inner tube provided in and spaced apart from the outer tube.[0002]Herein, the term “condenser” refers to not only an ordinary condenser but also a subcooling condenser, which has a condensing section and a subcooling section.[0003]A conventionally proposed refrigeration system for use in a car air conditioner includes a compressor; a condenser having a condensing section and a subcooling section; an evaporator; an expansion valve serving as a pressure-reducing device; a vapor-liquid separator; and an intermediate heat exchanger disposed between the condenser and the evaporator and adapted to perform heat exchange between a high-temperature refrigerant from the subcooling section of the condenser and a low-temperature refrigerant from the evaporator (as disclosed in, for example, Japanese Paten...

AI Technical Summary

Benefits of technology

[0006]An object of the present invention is to solve the above-mentioned problem and to provide a double-wall-tube heat exchanger exhibiting excellent heat exchange performance.

Problems solved by technology

However, the intermediate heat exchanger described in the above-mentioned publication involves the following problem: the area of heat transfer between the high-temperature refrigerant flow path and the low-temperature refrigerant flow path is small, resulting in insufficient heat exchange performance.

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