Abstract: Discussions were made on the fairness issue in experimentally assessing the cycle performances of various working fluids for refrigeration, air-conditioning, and heat pump systems with an experimental apparatus of a constant-speed compressor and fixed area heat exchangers.The additional temperature difference(Δt_plus),the partial heat transfer temperature difference，was identified to compare the working fluids at the same heat load to corrected area ratios in the evaporator and condenser respectively,and the equations for calculating Δt_plus and the thermodynamic perfection of the cycle (ε) were given.By adopting Δt_plus and ε,two modified experimentally assessing approaches were developed with much improved fairness and easy steps to operate.