Three types of absorption chillers - a single-stage cycle, a series cycle, and a parallel cycle - are compared by using energy utilisation diagrams (EUDs). By using EUDs, the exergy relation in the system is displayed and both the exergy loss and the driving force at pitch points are given graphically. From an exergy standpoint, the parallel cycle is found to be the best.

KEYWORDS: absorption refrigeration, absorption heat pumps, chillers, comparing, exergy.