Thermal performance assessment of an ejector air-conditioning system with parabolic trough collector using R718 as a refrigerant: A case study in Algerian desert region

Abstract

This paper investigates a safety control room with 18 kW of cooling load, where a parabolic trough collector is connected to an R718 ejector air-conditioning subsystem. Engineering Equation Solver is used as a programming tool to conduct the dynamic study of the proposed system. After model validation, the optical thermal and exergy efficiency of studied solar collector, main ejector diameters, ejector mass ratio, coefficient of performance of ejector air-conditioning subsystem, and solar performance coefficient (or system thermal ratio) have been accurately determined under different operating conditions. Regarding the studied solar collector, its optical, thermal, and energy performances are acceptable, with values of 79.15 %, 67.06 %, and 19.14 %, respectively. At the best-operating conditions (Tg = 413.15 K, Te = 283.15 K, and Tc = 298.15 K), the maximum performance of the ejector air-conditioning loop was estimated at 1.193, while the system thermal ratio for the studied solar air conditioner was 0.81. For a steady-state thermal operation, a hot storage tank was incorporated between the studied solar collector and the ejector air-conditioning subsystem with two different storage liquids (Therminol VP-1 oil and Hitec XL molten salt); the daily maximum storage temperature reached was thus 424.15 K.