Design and development of a solar refrigeration system

Abstract

When solar power, either thermal or photovoltaic, is used to provide energy to any refrigeration system, it is called as solar refrigeration system. The main objective of the study was to design and develop a solar absorption refrigeration system and performance evaluation of the developed system. In this study 40 L capacity three fluid vapour absorption refrigeration system (VARS) was designed and a commercially available three fluid absorption refrigerator working on electricity was procured and modified for using heat energy. The solar radiation at KCAET Tavanur was measured and it was observed that a maximum solar radiation intensity of 783.81 W/m2obtained at 1.00 PM at Tavanur. The performance of the modified VARS was tested using hot water obtained from solar water heater. It was found that the hot water from the solar water heater was not sufficient to produce any cooling effect. Hence a hybrid system using hot water from solar water heater and subsequent heating of the hot water using other heating sources such as electricity and LPG were utilized and the hot water was converted to steam at high temperature. Under this new set up the system worked perfectly and produced refrigeration. The performance of the modified VARS was then tested in the laboratory under simulated conditions using water at 100°C, steam at 103°C, 106°C, 116°C and 121°C and using electric heater. The experiments with low temperatures could not produce any cooling whereas steam at116°C and 121°C and electric heater at 150°C produced refrigeration effect. The corresponding generator temperature obtained were 105°C and 110°C and the ice tray temperatures were 6.8°C and 1.9°C. The temperature obtained in the cabin of the refrigerator was 10.9°C and 8.1°C which was ideal for keeping fruits vegetables and other perishable items. For effective working of this system using only on solar energy, instead of flat plate collector, a solar steam generator that could produce steam can be used.