Energy, exergy, exergoeconomic, and environmental (4E) analyses of a novel combined cooling and power system with phosphoric acid fuel cell and Kalina cycle

The use of combined energy systems with high efficiency, based on conventional or renewable energy sources can be a suitable option to overcome the existing limitations in the field of energy and reduce environmental pollutions. Therefore, choosing a fuel cell as the prime mover and also using its wasted heat in combined systems can increase the overall efficiency of the system and reduce fuel consumption, greenhouse gas emissions, and operating costs. In this study, a novel combined cooling and power system including a Kalina cycle and a single-effect water -ammonia absorption chiller is proposed to recover waste heat from the phosphoric acid fuel cell. In most of the previous works, a heat recovery system has been used for the phosphoric acid fuel cell, while in this study, two heat recovery systems (Kalina cycle and absorption chiller) with a new arrangement have been used with the fuel cell and analyzed from energy, exergy, exergoeconomic, and environmental perspectives. Impacts of current density, fuel price and carbon price on system performance have been studied and the net power and cooling load of system are evaluated. The results show that, the energy and exergy efficiencies, the unit cost of system, and the carbon dioxide emission penalty cost are 54.27 %, 45.48 %, 0.162 $ kW -1h- 1, and 9.557 $ h-1, respectively. Also, the carbon dioxide emissions decrease up to 147.6 g kW-1 h-1 and energy and exergy effi-ciencies increase to 52.32 % and 33.06 %, respectively compared to the operation of fuel cell alone. Also, the exergeoeconomic factors of fuel cell, inverter and turbine are 77.33 %, 57.41 % and 52.36 %, respectively, which are higher than other equipment. The highest exergy destruction belongs to the after-burner, which is about 20.35 % of the total exergy destruction of the system. Also, the lowest and highest cost rates of exergy destruction belong to pump 1 and absorber, respectively. The fuel cell has the highest overall cost rate due to its high in-vestment cost.