Modulation characteristics of a linear compressor for evaporating and condensing temperature variations for household refrigerators

•The modulation characteristics of a linear compressor were investigated numerically.•The effects of condensing and evaporating temperature variations were investigated.•A spring mass system was designed to realize a resonance system at general running conditions.•Cooling capacity was greatly affected by evaporating temperature than condensing temperature.

Linear compressors are sensitive to both condensing and evaporating temperatures since they do not have mechanical restrictions to piston movement. Linear compressors used in refrigerators are subjected to a wide range of compression loads, because of the condensing temperature change caused by the ambient temperature variations and the evaporating temperature change due to the freezer compartment temperature. The compartment temperature is influenced by door opening, product loading, defrosting and setting temperature. This paper presents modulation characteristics of an inherent capacity-modulated linear compressor for evaporating temperature variations representing compartment temperature change. A numerical model and a prototype compressor were developed. The prototype compressor was evaluated over an evaporating temperature from −35 to −15 °C. The results were compared with the compressor performance variations over a condensing temperature from 30 to 50 °C. The cooling capacity increased by 241 and 50 W for 20 °C increment of the evaporating and condensing temperature, respectively.