Simulation of solar cooling system based on variable effect LiBr-water absorption chiller

Abstract

In solar absorption cooling system, the instability of solar power causes mismatch between the solar collector and the absorption chiller. The variable effect absorption cycle was proposed to improve this. In order to investigate its solar driving performance, a Compound Parabolic Collector (CPC) driving variable effect LiBr-water absorption cooling system is simulated. Model of the variable effect LiBr-water absorption chiller is built through artificial neural network (ANN) modeling based on 450 groups of experimental data. Good agreement between the prediction and experimental data is achieved with correlation coefficient of 0.994. The CPC driving absorption cooling system is then built in TRaNsient SYstem Simulation program (TRNSYS) based on the chiller model. The daily performance of this system is calculated and analyzed. The variable effect chiller can work with low driving temperature, which guarantees a long working period. Besides, the variable effect chiller has high COP under high driving temperature, which ensures a competitive overall efficiency. The calculation shows that average chiller COP of 0.88 and solar COP of 0.35 are obtained. The effects of solar collector area, storage tank volume and cut-off driving temperature on the system performance are analyzed. The optimal solar collector area and tank volume are obtained.