A Method To Estimate The Performance Of Reciprocating Compressors

This paper proposes a method of evaluating the performance of reciprocating compressors. An analytical formula of the volumetric efficiency is presented. This formula, based on both theoretical and empirical approach, takes account of the most important factors, which occur during the working process of the compressor and affect the refrigeration performance. An accurate determination of the clearance volume of the compressor and a good knowledge of the temperature of the suction gas in the cylinder are required, to get a good agreement between calculation and experiment. The simulation of the capacity and the compression work, under various operating conditions, can give a good idea of the compressor performance. The method presented can be easily computed and should help the compressor designer at very early step of his engineering process. NOMENCLATURE Q : cooling capacity m q : mass flow rate H ∆ : enthalpy difference ρ : gas density v q : volume flow rate V : volume f : frequency V η : volumetric efficiency τ : compression ratio γ : polytropic exponent of compression and expansion process ε : clearance volume ratio M : molar mass P : absolute pressure R : ideal gas constant T : absolute temperature α : warm up coefficient