Comparative study of advanced heat pumps
Abstract
A numerical simulation study is reported on the thermodynamic performance of several non-CFC refrigeration devices. The study includes complex compound absorption, Brayton, Stirling, and thermoelectric devices. Comparisons are made to the more commonly applied vapor compression systems, including those using R-134a. The study examines the effect of thermal resistances between the device and the heat rejection or heat absorption space. A cool side temperature difference between 0 and 20{dollar}\sp\circ{dollar}C is investigated, and this temperature difference accounts for both thermal resistance and cooling load. An outside temperature ranging between 35{dollar}\sp\circ{dollar}C and 46{dollar}\sp\circ{dollar}C is considered in the calculations, with a cooled space temperature of 22{dollar}\sp\circ{dollar}C assumed throughout. Evaluations of the coefficients of performance for each of the units show the vapor compression machines demonstrate superior performance over the complete range of operating conditions examined. However, additional requirements, such as maintenance and environmental factors, indicate other desirable options.