Experimental Investigation of Heat Transfer in Components of a Hermetic Reciprocating Compressor under Thermal Transient
gas superheating, heat transfer, thermal transient.
Heat transfer has an important role on the efficiency and reliability of hermetic reciprocating compressors adopted forÂ household refrigeration. Most analyses of such compressors are carried out for fully-cyclic operating conditions basedÂ on established procedures and standards. However, since household refrigeration systems work by alternating periodsÂ in which the compressor is on (ON) and idle (OFF), the performance assessment of compressors should take intoÂ account the ON/OFF cyclic operation. This paper presents an experimental study of the heat transfer in componentsÂ of a hermetic reciprocating compressor during thermal transients due to ON/OFF cyclic operation. The compressorÂ was instrumented with thin-film heat flux sensors and thermocouples to evaluate time-varying heat transferÂ coefficients. We found that heat flux in some regions is significantly affected by the cyclic operating condition.Â Moreover, the investigation revealed the presence of different time scales due to distinct thermal inertia and heat transfer associated with each component.