Thermodynamic, exergoeconomic, and environmental evaluation of a new multi-generation system driven by a molten carbonate fuel cell for production of cooling, heating, electricity, and freshwater

摘要

Because of the ever-growing demand for energy in today's world, new efficient multi-generation systems are much sought after. Analyzing the practicality and performance of such innovative systems, especially ones utilizing novel energy conversion technologies, has been a popular subject among scientists. In this paper, a comprehensive assessment of a novel multi-generation system driven by a molten carbonate fuel cell is presented from thermodynamic, exergoeconomic, and environmental viewpoints. The proposed system consists of a molten carbonate fuel cell for electricity generation, a heating process heat exchanger for superheated steam generation, a generator-absorber heat exchanger cycle for generating cooling load, and a desalination subsystem for producing freshwater. To investigate the performance of the system, the influences of two important parameters, namely current density and fuel cell operating temperature, are studied on the generated cell voltage as well as the production rates of the products, the energy and exergy efficiencies, the cost rate, the cost per unit exergy, and the carbon dioxide emission rate. According to the results, the net electrical power production and the energy and exergy efficiencies of the proposed system are 1439 kW, 79.9%, and 51.9%, respectively. Also, the investment cost rate of the system is 30.4 $/h, which results in the production of the mentioned outputs with a total cost per unit exergy of 21.6 $/GJ. Moreover, the carbon dioxide emission rate of the system is found to be 247 kg/MWh.