Exhaust gas flow (leaving the engine catalyst) was controlled by two step-motor driven valves (labelled V1 and V2 in Fig. 1). Valve V1 is responsible for regulating gas flow directly to the generator whereas valve V2 controls the amount of gas rejected to the atmosphere. Exhaust gas temperature was monitored before (TI) and after (TO) heat exchange with the generator. The evaporator and generator temperatures (TE and TG, respectively) were also monitored continuously during the tests. The coefficient of performance (COP) of the absorption refrigeration system is given by a ratio of
the instantaneous cooling capacity ðQ _ refÞ and the instantaneous heat transfer rate from the energy source ðQ _ exhÞ to the absorption refrigeration system, both given in W: