Energetic, Exergetic, Economic and Environmental (4E) analysis of a solar assisted refrigeration system for various operating scenarios

Abstract

The objective of this work is to investigate the yearly performance an absorption-compression cascade refrigeration system driven by solar energy. Different operating scenarios are examined by testing different combinations of refrigeration and condensation temperatures. Evacuated tube collectors coupled to a storage tank are selected to be used for feeding the refrigeration system with the proper heat demand. LiBr-H2O and R134a are selected as working pair in the absorption cycle and refrigerant in the compression cycle respectively. The analysis is performed in energetic, exergetic, economic and environmental terms with a developed and validated model in EES (Engineering Equation Solver). According to the final results, the cascade system, in cases with low refrigeration temperatures is better economically while in higher refrigeration temperatures presents the greater percentage of electricity savings. On the other hand, higher heat rejection temperature leads both to higher economic indexes and to higher electricity savings. For the case of heat rejection at 40°C and refrigeration at −20°C, the electricity savings are found 53.98%, the IRR 6.6% and the payback period close to 14years.