Exergetic analysis of an absorption/compression refrigeration unit based on R124/DMAC mixture for solar cooling

摘要

This work presents an energetic and exergetic analysis of an upgraded frigorific production unit, operating with a novel organic mixture: DMAC/R124 (N, N'-dimethylacetamide/2chloro-1,1,1,2-tetrafluoroethane). Investigated parameters are the COP (performance coefficient), the irreversibility and the exergetic efficiency. Performances of the proposed mixture system are compared with those relative to the classical water/ammonia system. Results show that the COP obtained with the new fluids is similar to that relative to the old one, it is about 64% for a compression ratio about 2, while the same optimum value is achieved with a compression ratio about 3.3 when working with ammonia/water. Furthermore, the system using the new proposed couple uses lower threshold temperatures, between 60 degrees C and 80 degrees C as optimum COP, which allows the use of low temperature energy sources.