Yearly investigation of a solar-driven absorption refrigeration system with ammonia-water absorption pair

The objective of the present investigation work is the analysis of a solar-driven refrigeration unit with parabolic trough solar collectors. The refrigerator is a single-stage absorption machine with NH3/water working pair for producing refrigeration in the temperature range from -35 degrees C up to 5 degrees C. The system is studied energetically, exergetically and financially. The yearly analysis is performed for the weather data of Athens, Greece. The thermodynamic model was created in Engineering Equation Solver and it is validated with literature data, while the dynamic model was programmed in language Matlab. More specifically, the thermodynamic analysis is conducted by applying the energy rate balances and the mass flow rates balances in the system devices, while the dynamic analysis is performed by applying the energy balance in the storage tank of the solar field. According to the final results, there is an optimum generator temperature that maximizes the system performance and it is depended on the operating conditions. For refrigeration product at -20 degrees C and heat rejection at 40 degrees C, the yearly system coefficient of performance is 0.255, the yearly exergy efficiency 4.86% and the simple payback period is close to10 years.