Exergy analysis of an experimental ammonia/water absorption cooling system

Abstract

This study proposes a second-law analysis of an experimental ammonia-water absorption cooling system, assessed under different operating conditions. The study also includes an analysis of what is considered the most significant research of exergy analyses on experimental absorption systems. The approach proposed in this study takes into consideration two types of exergy: chemical and physical, to determine the irreversibilities in the absorption system. Special attention has been paid to the contributions of the chemical exergy in the absorber, generator, and rectifier. Also, an evaluation of the exergy destruction as a part of the total exergy supplied to the system and its variation within the considered conditions range is presented. The effect of the variation of the dead-state temperature on the system’s irreversibility is also evaluated. Moreover, the components' irreversibilities contribution and their possible causes are discussed and presented for the main system components. Finally, the second-law efficiency or exergy coefficient of performance (ECOP) is reported as a function of the heating and cooling water temperatures. The highest ECOP achieved by the absorption system was 14.4%.