An experimental and numerical study on an inherent capacity modulated linear compressor for home refrigerators

Linear compressors are built based on a free piston system and usually require stroke controllers, since the piston movement is sensitive to the ambient temperature. This paper presents a novel design method for an inherent capacity modulated linear compressor that uses R600a for application in household refrigerators. The compressor is capable of modulating its capacity independently, and this feature secures stable and efficient operation without requiring stroke controllers. Electrical parameters are designed to deliver inherent capacity modulation in accordance with cooling demand variation. Mechanical parameters are tuned to establish an efficient resonance system. A numerical model was developed and a prototype compressor was constructed. The prototype compressor was evaluated over a condensing temperature range of 15-50 °C, which corresponds to an ambient temperature range of 5-43 °C. The simulation results show that the cooling capacity was inherently modulated from 55 to 90% over the ambient temperature range, and the inherent modulation is confirmed 70-90% by the experiment.