The low compressor efficiency registered during earlier test can based on the result reported below be quantified and much better understood.
The fixed compressor has a isentropic efficiency of around 40% instead of expected around 70% the total COP is due to this decreased from approximately 8.1 to measured 5.2 at the only test where operation of the fixed was measured after additional sensors were added. At this condition Variable compressor was running at low speed at higher load the variable compressor with better performance will decrease the impact somewhat. It is recommended that this compressor should be replaced before a total failure result higher repair costs. The design of oil return also cause clearly measurable losses but due to that these gradually disappear with only the limited amount of measured operation the impact of this cannot be quantified with accuracy but it is clearly limited and much smaller impact than the poor compressor.