Thermodynamic optimization of utilization of LiBr+LiCl/H2O solution mixture on a single-effect absorption chiller driven by solar energy

Abstract

The interest in absorption chillers for air conditioning applications has increased recently due to the negligible electricity requirement. Especially in Turkey, where the potential of renewable energy sources such as solar energy is high, it is possible to achieve significant energy savings by utilizing absorption chillers. This study presents comprehensive energy and exergy analyses of a solar-driven single-effect absorption chiller with LiBr+LiCl/H2O (mass ratio 2:1) solution mixture. Thermodynamic optimization is carried out for the first time in this study to determine the optimum generator temperature using different absorber and condenser temperatures to maximize exergy efficiency of the absorption chiller. Also, generator temperature ranges for each absorber and condenser level are determined in this study so that the chiller using solution mixture can operate without crystallization. Coefficient of Performance, total exergy destruction rate and exergy efficiency of solar-driven absorption chiller for solar collector area of 194 m2 under a certain optimized operating condition are 0.402, 113.63 kW and 1.255%, respectively. Thanks to an alternative solution mixture compared to LiBr/H2O, the effective thermodynamic parameters can be improved and become more advantageous. The comparison results demonstrated that the thermodynamic performance of the system not only increased but also the thermal capacities and collector area decreased.