22 May 2008

A SINGLE-EFFECT ABSORPTION HEAT TRANSFORMER FOR WASTE HEAT RECOVERY IN INDUSTRIAL USE


A single-effect absorption heat transformer has been developed. It is driven by waste heat, as 90°C water, from a gas engine, and the outlet temperature from its generator and evaporator is 85°C. The output temperature from its absorber is 137°C, so the temperature boost is 52°C. We proposed a new performance evaluation method, based on
thermodynamics and Duhring’s law, for comparing machines, which are designed for different operating temperatures. By this method, the coefficient of performance (COP) and temperature boost are estimated from the ratio to their theoretical values. According to this method, the temperature boost of the heat transformer is 84% of the theoretical value and exceeds previously developed single-effect absorption heat transformers. The COP of the heat transformer is 0.484. Additionally, two solution pumps, adopted for the solution circuit, shorten the start-up time to less than one hour. This absorption heat transformer was installed with a co-generation system in a hydraulic machinery factory. Regular operation began in April 2007. This system has been operating as originally designed and without any problems.