In this paper, a multi-generation system based on geothermal energy and parabolic trough solar collectors is proposed for the simultaneous generation of power, cooling, freshwater, hydrogen, and heat. Power is generated by a combined steam Rankine cycle and an organic Rankine cycle. Ten different refrigerants are used for the organic Rankine cycle, among which R123 has the best performance. In addition, four fluids are used as the geothermal fluid, among which Therminol 59 has recorded the best performance. Solar intensity, geothermal mass flow rate, geothermal fluid temperature, and steam turbine inlet pressure have proven to be the most prominent parameters affecting the exergy efficiency and cost. After analyzing the proposed system from the energy, exergy and exergoeconomic points of view, a multi-objective-optimization-genetic-algorithm is applied for improving the performance of the system. In order to apply the multi-objective optimization, Engineering Equation Solver and MATLAB software are linked together by the Dynamic Data Exchange method. According to the obtained results. The results show that the exergy efficiency of the system and the total unit cost respectively reach to 29.95% and 129.7 $/GJ at the optimum point.