EQUIVALENT CARNOT CYCLES FOR SORPTION REFRIGERATION

Temperature-entropy diagrams are usually used to describe heat-driven engines as well as vapour compressor refrigerators, but they have not yet been used for sorption refrigeration. Such Carnot cycles are intro duced here to describe three sorption refrigeration technologies (liqu id absorption, solid adsorption, chemical reaction). This is performed for basic cycles (without heat recovery) and for simple advanced cycl es. Equivalent four-temperature Carnot cycles are obtained for basic c ycles, whereas equivalent six-temperature Carnot cycles are obtained f or advanced cycles. This approach shows that the quantity Delta H-T De lta S (where Delta H and Delta S are the enthalpy and entropy variatio ns associated with mass transfer during a cycle in/out of the sorbers) plays the same role as the mechanical energy in vapour compression cy cles. (C) 1998 Elsevier Science Ltd and IIR. All rights reserved.