Exergetic and energetic comparison of LiCl-H2O and LiBr-H2O working pairs in a solar absorption cooling system

The objective of this study is to investigate the use of an alternative working pair in a solar absorption cooling system. LiCl-H2O is the new examined pair and it is compared energetically and exegetically with the conventional pair LiBr-H2O, which is the most usual in air-conditioning applications. The simplest solar cooling system is analyzed in order to focus in the comparison between these working fluids. Specifically, flat plate collectors, coupled with a storage tank, feed the single effect absorption chiller which produces 250 kW cooling at 10 degrees C. The two pairs are examined parametrically for various heat source temperature levels and for three ambient temperature levels (25 degrees C, 30 degrees C and 35 degrees C). The minimization of the collecting area, which means maximum exergetic efficiency, is the optimization goal in every case. The final results show that LiCl-H2O pair performs better in all cases by giving greater exergetic efficiency. More specifically, about 8% lower collecting area is required to cover the demanded cooling load with this working pair. Another interesting result is that the optimum heat source temperature for the LiCl-H2O is roughly lower than the respective for the LiBr-H2O. The system is analyzed in steady state with the commercial software Engineering Equator Solver (EES). (C) 2016 Elsevier Ltd. All rights reserved.