Development of a High Ambient Temperature Cooling Unit Based on Microcompressor Technology

摘要

A good matching between size and efficiency is a desirable design feature of cooling units for electronic systems, due to high capacity to size ratio and small weight. For this purpose, Embraco developed a new refrigerating system for small enclosures and telecommunication stations, which makes use of a new miniaturized linear microcompressor. The air-conditioning cooling unit consists of finned-tube heat exchangers and a direct current (DC) oil-free microcompressor that uses R-134a as the refrigerant. The paper presents a detailed description of the cooling unit and performance tests. A novel refrigerating cycle for thermal management of the microcompressor was created especially for high ambient temperatures. In order to run all experimental tests, a cooling unit calorimeter was assembled. In the experimental facility, the ambient temperature was varied (25, 35 and 55 °C) and the bulk temperature inside the enclosure was controlled via an electric heater. Commercially available thermoelectric systems used for electronics cooling were also compared with the vapor compression system. The results have shown that the microcompressor unit presented a coefficient of performance (COP) approximately two times larger than thermoelectric solutions.