A Comparative Study of Four Air Conditioning Technologies

Numerical simulations of the thermodynamic performance of four non-CFC refrigeration technologies in the human comfort temperature range is reported. The study includes complex compound absorption, Brayton cycle, Stirling cycle, and thermoelectric refrigeration devices. Comparisons are made to the more commonly applied vapor compression systems, including those using R-134a. Outside temperatures ranging between 35° C and 46° C are considered in the calculations, with a cooled space temperature of 22° C used throughout. This study is idealized to the extent that thermal resistance between the device and the heat rejection and heat absorption spaces is set to zero. Vapor compression machines demonstrate overall superior efficiency performance. Of the alternative technologies the thermoelectric device has the best coefficient of performance, although the performance decreases significantly with increasing ambient temperature. The Stirling machine and complex compound absorption show an advantage by demonstrating near-constant performance over a wider temperature range.