Due to the variable heat source problem for an adsorption cooling system in the practice, a silica gel-water adsorption chiller was experimentally studied, which was driven by recovered heat from gas engine. The chiller consisted of two desorption/ adsorption chambers and one heat-pipe working chamber of evaporator. The experimental results show that the cooling power with the 65℃ variable hot water temperature attains 63% of one under 90℃, and the COP (coefficient of performance) of the chiller has a small change which may be ignored. The transient refrigeration performance of the chiller has the good repeatability and stability. It was proved that the chiller driven by variable heat source is very reliable and good for low-grade heat source. This technology approach is feasible to be used for low temperature grain storage with combination of adsorption cooling and solar thermal or waste heat utilization.