Exergy and exergoeconomic comparative analysis of three NH3-NaSCN absorption refrigeration cycles driven by solar collector

In this study, three different configurations of absorption cycles are compared and analyzed from exergetic and exergoeconomic points of view. These configurations include the simple absorption cycle, the combined ejector-absorption cycle, and the combined compression-absorption cycle, as well as a flat plate solar collector and a storage tank. Ammonia sodium thiocyanate is used as the working solution. In both combined cycles, the absorber operates at intermediate pressure, allowing three pressure levels to be considered. The simulations are performed using EES software. According to the base case results, in all three cycles studied, the solar collector should be taken into account more than other components in terms of exergy and exergoeconomic, because it has the highest amount of exergy destruction, the highest exergy destruction cost rate and the highest cost rate. The results of the systems parametric analysis show that as the pressure ratio of the ejector and compressor increases, the solar collector area and the heat rate of the generator decrease. Furthermore, by increasing the pressure ratio of the ejector and compressor, the economic factors are reduced, thus improving the exergoeconomic performance of the combined cycle compared to the simple absorption cycle. It is also observed that for the same pressure ratio of ejector and compressor, the exergy efficiency of the ejector cycle is slightly higher than that of the compression cycle. On evaluation of the results, the effect of the generator temperature on this improvement is clearly evident. Finally, on the basis of the results, since the highest pressure ratios can be obtained in the combined solar compression-absorption cycle, this configuration has the best performance among the three cycles studied from an exergetic and exergoeconomic point of view, except for the exergy efficiency, which increases in the combined solar ejector-absorption cycle. Exergetic operating parameters, such as coefficient of performance, solar coefficient of performance and solar exergetic efficiency, are higher in the compression-absorption cycle than in the ejector-absorption cycle. The compression-absorption cycle shows a significant reduction in exergoeconomic factors, such as the total investment cost rate, the total cost rate of exergy destruction, the total cost rate and the unit cost of cooling production, indicating that the use of the compressor in the absorption refrigeration cycle leads to a better performance compared to the use of an ejector.