We experimentally show that for the same heat exchanger inventory allocation, a four-bed adsorption chiller delivers a 12% higher ultimate cooling capacity than its two-bed counterpart. In addition it delivers a significantly improved quality of instantaneous cooling than a two-bed chiller at the same cooling capacity. The COP-enhancing feature of a passive heat recovery scheme that does not involve additional pumping action or valves is experimentally proven. It improves the COPs of a two-bed chiller and a four-bed chiller by as much as 38 and 25%, respectively, without any effect on their cooling capacities. The highest Cops achieved with a two-bed and four-bed chillers are 0.46 +/- 0.02 and 0.45 +/- 0.02, respectively. These are measured at a hot-water inlet temperature of 85 T, cooling-water inlet temperature of 29.4 degrees C and chilled-water inlet temperature of 12.2 degrees C. (c) 2004 Elsevier Ltd and IIR. All rights reserved.