Fundamental Study off High-Efficiency Rolling-Piston-Type Compressors for Refrigerators

In order to further improve the efficiency of rolling-piston-type compressors for refrigerator use, the anthers have measured the performance of current compressors and estimated each loss quantitatively, Because of high compression ratios and less refrigerant flow, the losses caused by superheating the refrigerant suction gas are considerably high, The mechanical and •otor loss also account for a considerable part of losses. Based on this esti•ation, we re-designed the fundamental structure of the compressor, and reduced these losses. A prototype compressor has been designed, constructed and tested. This paper describes the loss analysis, the design of prototype compressor and its test result. INTRODUCTION Rolling-piston-type co•pressors are typical ones with aany characteristics such as COno suction valves GOa s•ooth compression process QDgood rotating balance GDa small size and low manufacturing cost, In 1970 !ITSUBISHI Electric Corp. developed rolling-piston-type co•pressors for do•estic air-conditioning use, and developed compressors for refrigerator use with laid co•figuration in 1980. Since then •any · i•prove•ents have been carried out on efficiencY and function. <>> Two factors have li•ited further i•provements in the efficiencJ. They are (a)large losses caused by superheating the refrigerant gas unde~ high co•pression ratios and (b)significant •echanical losses. · The anthers haTe re~exa•ined the basic design of this compressor and tried to further i•prove the efficiency. For this purpose we have brushed up on loss analysis, heat and fluid analysis and •otor design technique. We estimated and appreciated each loss, searched after the •eans of loss reduction and re~designed the funda•ental structure of the co•pressor. Consequently we have found a way to i•prove the efficiency by 10~ on the prototype co•pressor. ANALYSIS OF PERFORMANCE Current Co•pressors As the object of the efficiency i•prove•ent study, we chose the ~oiling-piston­ type co•pressors with laid configuration for refrigerator use (we refer to it as the ~current co•pressor· fro• here on). !ajor specifications of the current co•pres~ sor are listed in Table 1. Table I Major SpecifiCiitioos ol the Compressor Compression Mechanism Stroke Volume Motor Dimension Weight !-cylinder, Rolling Piston Type 4.2cm single-phase IOOV, 130W class outer diameter: 92 mm, .length: 195 mm 5.2Kg