Experimental testing of an oil-flooded hermetic scroll compressor

In this work, a residential air conditioning compressor designed for vapor injection has been modified in order to inject large quantities of oil into the working chamber in order to approach an isothermal compression process. The compressor was tested with oil injection mass flow fractions of up to 45%. At an evaporating temperature of −10 °C and condensing temperature of 30 °C, the overall isentropic efficiency was up to 70% at the highest oil injection rate. Overall, over the testing envelope investigated, there are no significantly negative effects experienced for the compressor and the compressor isentropic efficiency and refrigerant mass flow rate improve monotonically as the oil injection rate is increased.

► Air conditioning scroll compressor modified for oil injection.
► Injecting more oil improves compressor efficiency monotonically.
► Tested to oil injection mass flow fractions of up to 45%.
► Compressor handles oil injection without any negative side-effects.