A steady state model was developed to predict the performances of a hot water driven lithium bromide aqueous absorption chiller.The chiller consists of an absorber,a generator,a condenser,an evaporator and a liquid heat exchanger.Lumped parameter method was adopted to build the model on account of the mass and energy conservation of each component.Thermodynamic coefficients and other parameters at each state point of the system were calculated based on the known component heat transfer areas,flow rates,inlet or outlet temperatures of the cooling and heating fluids and recycling ratio of the absorber.Based on the model,a computer code was developed to simulate the chiller under different operating conditions,and performance curves which indicate the variation of the coefficient of performane(COP) with the changes of the mentioned parameters were obtained.