IMPACT OF UNCERTAINTIES ON ESTIMATIONS OF HEAT-PUMP CYCLE PERFORMANCE

Sensitivity analysis is used to show how uncertainties in basic factor s, such as heat transfer, pressure drop, compressor efficiency, and th ermophysical properties, influence the result of heat pump cycle perfo rmance estimations. By comparing the results of this analysis with unc ertainty levels of estimations and experimental determinations, it is established to what extent improvements in accuracy are needed. The in vestigation was carried out for several different applications and, as working fluids, both pure substances and non-azeotropic mixtures were examined. It was found that evaporation heat transfer and compressor efficiency are two areas where improvements are needed. It is also sho wn that estimates using very accurate, substance-specific, equations o f state differ from those using more general types by up to 1% for COP and 2% for capacity.