Abstarct: In this thesis, a novel trigeneration system baxsed on a phosphoric acid fuel cell and an Organic Rankin Cycle is modeled and analyzed from energy and exergy viewpoint. in this thesis two configurations for trigeneration system proposed to recover wast heat energy of fuel cell. The system consists of an Hydrogen storage tank, phosphoric acid fuel cell, after burner, Organic Rankin Cycle, Thermal Energy storage tank, steam reformer, burner and heat excheangers . The proposed system, using Three heat recovery Systems (ORC-ACH-HX) to meet the Cooling, Heating and Power needs of a building in order to utilize wast heat from a fuel cell. The mathmatical models PAFC, ORC and ACH are validated with The results of other articles in This research, The effect of important PAFC performance Parameters (current density, temperature and operating pressure) on the performance of the proposed trigenerating system from the perspetcive of energy and exergy are investigated. The results show that the energy and exergy efficiency of the fuel cell in the first configuration are 55.52% and 56.42% respectively, and in the second configuration 51.66% and 49.42% have been calculated respectively. Whereas when three heat recovery systems (ORC-ACH-HX) to utilize the wast heat from a fuel cell, the energy and exergy efficiency in the first configuration reach 93.23% and 61.25% respectively and in the second configuration they reach 88.16% and 54.85% respectively. Also, the study show that as the current density and temperture of the PAFC increases, the energy and exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration both decreases. While increasing the operating pressure causes the increased energy and exergy efficiency in the expressed states. In addition, increases the working pressure leads to increases energy efficiency and exergy efficiency both. the highest exergy destruction in the first configuration is related to PAFC and AB respectively, while the second configuration the highest exergy destruction is related to SR,B and PAFC respectively. The highest and lowest exergy efficiencies in the both configuration are related turbin and domestic hot water heat exchengers respectively.