Purpose of ongoing book is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption chiller. At first, the solar absorption chiller is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated. These parameters consist of heat exchanger effectiveness, heat transfer cross section area, heat transfer coefficient, efficiency of pump and motor. Designing a storage system is necessary for supporting system when sunshine is not received adequately, especially at night. Therefore, in the second a rectangular storage system with Phase Change Material (PCM) technique designs that its main parameters were calculated by enthalpy and finite element methods.