HO-2671 -- A New Absorber Heat Recovery Cycle to Improve COP of Aqua-Ammonia Absorption Refrigeration System ✓ Most Recent

Absorption refrigeration is, in principle, an attractive method for using heat energy directly for cooling purposes. The chief advantage the vapor absorption system enjoys over the vapor compression system is that the former mainly requires heat energy at moderate temperatures, while, in the latter, the energy input is shaft work, which is a high-grade energy. A relatively large amount of work is required, because, during compression, the vapor undergoes a large change in specific volume. On the other hand, in an absorption system, the working medium remains in a liquid phase during compression, there is very little change in the specific volume, and the work input is relatively small. The absorption process in an absorption refrigeration system releases a large amount of heat. This heat is evolved at temperatures considerably above the ambient temperature, which results in a major irreversible loss in the absorber. This paper proposes a scheme to utilize this heat for improving the Coefficient of Performance (COP). Detailed analyses of the conventional system and the modified system are included to serve as a basis for the component design. The performance curves based on the above analyses are presented to show the effects of various operating parameters, such as the generator temperature, the absorber temperature, and the effectiveness of heat exchangers and the rectification column.