Experimental performance assessment of a hermetic reciprocating compressor operating in a household refrigerator under on-off cycling conditions

This paper reports a study on the performance of a hermetic reciprocating compressor operating in a household refrigerator. The refrigerator was provided with sensors to measure the mass flow rate and evaporating and condensing pressures, while the compressor was instrumented with thermocouples in selected components and pressure transducers to measure the p-V diagram. Tests were conducted at ambient temperatures of 32°C, 25°C and 16°C with different freezer cut-off temperatures (−10°C, −16°C and −19°C). The phenomena that affect the mass flow rate and power consumption were evaluated during typical on-periods. It was observed that the thermodynamic efficiency of the compressor varied by 5-10% during the first few minutes after the compressor start-up, but remained virtually constant throughout the remainder of the on-period. The results showed that the volumetric and thermodynamic efficiencies tend to increase at lower ambient temperatures, while the overall efficiency of the compressor remains practically constant. Additionally, the compressor average temperatures and efficiencies collected from the application tests were compared to data obtained with calorimeters, revealing that the two sets of data do not differ much from each other.