A novel silica gel-water adsorption chiller is developed. This chiller consists of three vacuum chambers: two adsorption/desorption (or evaporation/condensation) vacuum chambers and one heat pipe working vacuum chamber. In this chiller, only one vacuum valve is installed between the two adsorption/desorption vacuum chambers to improve its performance when it is driven by a low temperature heat source. The operational reliability of the chiller is highly improved because of fewer moving parts. In this work, the performance of the chiller is experimentally tested under a low grade heat source, such as 55-67 degrees C. The test results show that the performance of this chiller is satisfying when it is driven by a low grade heat source, such as 65 degrees C, and the cooling capacity (or refrigeration capacity) will reach about 5 kW when the hot water temperature is 65 degrees C, the cooling water temperature is 30.5 degrees C and the chilled water inlet temperature is 15.1 degrees C. The test results confirm that this kind of adsorption chiller can be effectively driven by a low grade heat source. (C) 2007 Elsevier Ltd. All rights reserved.