Experimental investigation of a solar-charged sorption thermal battery

Abstract

In the present study, an integrated solar-driven sorption energy storage unit was investigated under real climatic conditions in Famagusta, North Cyprus. Vermiculite-CaCl2 was selected as the working material due to its high energy density, good cyclic ability and low cost. Three series of charging-discharging experiments were performed employing the developed solar-driven thermochemical heat storage system. The discharging tests were performed during the night for duration of 5 h. During the discharging experiments, temperature and relative humidity of inlet air were between 21 and 24 degrees C and 80% and 90%, respectively. Under these conditions, the average energy output over three cycles was found to be 2.1 kWh, with an average energy storage density of 156 kWh/m(3). A manufactured parabolic solar concentrator was utilized to provide the required thermal energy in the charging process. Hence, the average surface temperature of the reactor was in the range of 78 degrees C-83 degrees C. The average solar energy supply and desorption energy utilized in the charging process were 5.56 and 1.75 kWh, respectively. The rate of moisture desorption was 6.5 g/min while the thermo-cyclic efficiency was 38%.