Experimental evaluation of a solar two-bed lab-scale adsorption cooling system

A lab-scale two-bed adsorption chiller can be driven by solar energy was designed, constructed and evaluated experimentally in Thermal Engineering Lab, Alexandria University, Egypt. Isotherms characteristics of silica gel that was packed in the two beds were determined depending on the experimental DVS (dynamic vapor sorption) analyzer results. To visualize the sorption phenomena in the two beds and in the evaporator during the adsorption and desorption cycle, a special transparent glass was used as the upper cover for these components. The time variations for the temperatures and pressures at each component were measured, simulated and analyzed. The system performance was experimentally investigated under various operating conditions. The results showed that the specific cooling capacity (SCC) was about 75 W/kg while the coefficient of performance (COP) was 0.42, when the hot water inlet temperature was 75–80 ℃, the cooling water inlet temperature was 25 ℃, and the chilled water inlet temperature was 14 ℃. Effects of adsorption/desorption times and chilled water temperatures (Tch) on the chiller performance were investigated.