Exergoeconomic analysis and comparison between ammonia/water and ammonia/salt solar absorption refrigeration cycles

This research analyzes and compares the exergy and exergoeconomic performance of six chiller configurations to produce 300 kW of cooling. The configurations are the simple absorption and the combined ejector absorption refrigeration cycles using ammonia-water (NH3-H2O), ammonia-lithium nitrate (NH3-LiNO3) and ammonia-sodium thiocyanate (NH3-NaSCN) driven by flat plate solar collector and storage tank. The objective of this research is to determine which ammonia-based working fluids provide superior performance in solar absorption cooling systems. The results show that with an increase of the generator temperature in the absorption cycles, as well as with an increase of the ejector pressure ratio in the combined ejector absorption cycle with NH3-NaSCN as working fluid, the solar and economic factors improve, especially at higher generator temperatures compared to these cycles with NH3-LiNO3 and NH3-H2O as working fluids. Regarding the unit cost of cooling production, the studied cycles with NH3-LiNO3 show a better performance. In the combined ejector cycle with ammonia-sodium thiocyanate, which has the best performance among the cycles studied, the solar coefficient of performance and the solar exergy efficiency are equal to 0.21 and 1.659%, respectively. Also, the total cost rate and the unit cost of cooling production in the mentioned cycle are equal to 415.7 $/hr and 52.15 $/GJ, respectively.