Performance characteristics of a capacity-modulated linear compressor for home refrigerators

A linear compressor requires stroke controllers, as the piston movement is sensitive to the ambient temperature. This paper presents the performance characteristics of an inherent capacity-modulated (ICM) linear compressor. The compressor is capable of modulating its capacity independently without requiring stroke controllers. Electric parameters are designed to deliver inherent capacity modulation in accordance with variations in the cooling demand. An inherent capacity modulation method according to cooling demand levels was proposed and a prototype compressor was constructed. Its performance was evaluated with the cooling capacity ratio varying from 50 to 100% at an evaporating temperature of −26 °C and a condensing temperature of 38 °C. The total efficiency of the ICM linear compressor was as high as that of an electrical resonant system. This shows that the COP difference between the ICM linear compressor and the linear compressor controlled by an electrical resonance system appeared to be less than 1% over a wide cooling capacity ratio range of 50–100%. The results for the conventional linear compressor did not account for the power consumed by the electronic drive, so thus the ICM linear compressor had the potential improvement for energy saving.