A solar-driven ejector refrigeration system for Mediterranean climate: Experience and performance

Within the framework of the European research PROGRAM, a solar-driven refrigeration system using ejector cooling cycle was installed in the National Engineering School of Tunis (Tunisia) in order to provide some offices in the school with solar cooling. The project entitled Mediterranean “AIRCOND” aims to study and investigate the performances of advanced solar drive air conditioning system for Mediterranean building. The system was designed and laboratory tested in the UK and then transferred to Tunisia for field evaluation. The heating loop is composed of a solar array of a 60 m² solar field sunrain evacuated tube; the tilt angle is 45°, they are facing to south. A 3000 L tank is used as hot water storage. it is equipped with a 7KW auxiliary heater to ensure dry saturated steam to the ejector. An additional 2.4 kW boiler is added to ensure immediate hot water supply to the generator during or cloudy condition, this will ensure steady state conditions to the ejector loop. The produced coolness is stored in an 800 liters tank sealed with micro-encapsulated phase change materials (MEPCM). This paper presents the experience gained during the system construction as well as experimental results obtained from the system. Different operation strategies were adapted to obtain double choking of the ejector. Successful operation of the ejector was obtained for short periods, though several challenges remain for commercial exploitation of this system.