The silica gel-water working pair has been commonly used for commercial adsorption chillers due to the environmental benign refrigerant and low desorption temperature (less than 85°C). However, the application has been constrained due to the vacuum working condition and Ice point. This motivates researchers to investigate alternative working pairs. The silica gel-based adsorbents - ammonia working pairs have been found to be the most promising alternative. The isotherms and heats of adsorption of the working pair are essential to be investigated for designing the adsorption reactor and predicting the chiller performance. A novel sensor-gas calorimeter has been used to simultaneously measure the adsorption isotherm and heats of adsorption. The experimental results for adsorption of ammonia on the pure silica gel and silica gel treated with different weight percentage of calcium chlorine are presented.