Performance evaluation of the solar-driven multi-ejector refrigeration cycle without an auxiliary heat source

Abstract

• Performance of a novel solar-driven multi-ejector refrigeration cycle is evaluated. • The proposed system does not need an auxiliary heat source and cooling system. • System is equipped with an internal heat exchanger, regenerator, and storage tank. • Sensitivity analysis and the system’s parametric optimization are carried out. • 75% lower solar collector area is required by the proposed system. Solar-driven ejector refrigeration (SER) systems have been granted special attention as a green and sustainable replacement for conventional vapor compression cooling systems. However, despite their significant advantages, SER systems suffer from a relatively low coefficient of performance and failure at high ambient temperatures and low solar radiations. Therefore, the need for an auxiliary heat source and cooling system has hindered their adoption in practice. In an attempt to eliminate the need for an auxiliary heat source and cooling system, this contribution puts forward a novel Solar-driven Multi-Ejector Refrigeration (SMER) system with an internal heat exchanger, a regenerator, and a storage tank. A numerical model of the proposed SMER system and a computational fluid dynamics model of the ejector have been developed. The developed model is then used to evaluate the dynamic annual performance of the proposed SMER system through a case study. Shape optimization is also carried out to optimize each ejector based on its specific working conditions. The sensitivity of the system performance to design parameters is also analyzed, and the optimum design parameters are determined. According to the results, the proposed SMER system can provide up to 94% of the required cooling load of the sample building with a 250 m 2 solar collector area. However, the conventional SER system can provide only 71% of the building load. It is also demonstrated that the proposed SMER system requires a 75% lower solar collector area than the conventional SER system to provide 100% of the required cooling load.