Vapor Compression Cooling Cycles

Abstract

In this chapter, we examine vapor compression cycles for refrigeration and air conditioning. We review the Carnot cycle, then perform a thermodynamic analysis of basic vapor compression cycles to illustrate the various thermal efficiency metrics and the effect of condenser and evaporator temperatures. The Carnot cycle, since it is reversible, is the most efficient possible, and thus is the standard to which all real cycles are compared. We use three related parameters, COP, EER, and SEER, to quantify the thermal efficiency of thermodynamic cooling cycles. We then discuss the thermodynamic properties of common refrigerants, compute part load performance, and finish with an analysis of multistage vapor compression cooling cycles. With increasing climate change due to the buildup of greenhouse gas emissions in the atmosphere, there has been a worldwide impetus to transition to refrigerants that have a low or even zero global warming potential.