A vapor compression refrigeration system including components capable of determining the superheat at a compressor inlet is provided. Preferably, the light source is an OLED that is structured into a plurality of electroluminescent zones and inactive zones. The sanding platen may be driven by the motor for movement relative to the housing. An orifice portion of the orifice joint applies a throttling function to the circulating oil liquid whereby a frictional heat is generated therein.