A hybrid air conditioning system consists of a gas engine as a driving source and a hybrid refrigerator which can be driven by waste heat and motive power simultaneously. It can improve the efficiency of the gas engine heat pump greatly because it uses waste heat from the gas engine. This paper aims to estimate the performance of this hybrid air-conditioning system by the simulation. The objective hybrid refrigerator is composed of the single and double effect absorption type and the single-stage compression type refrigerator. The static simulation model of the hybrid air conditioning system is constructed and the performance is simulated using the model. As a result of the simulation, higher performance part load can be realized by changing the backup gas flow rate and hot water flow rate.