A year-round investigation of an integrated system based on reversible solid oxide cell

This paper proposes and investigates an integrated system, centered around a reversible solid oxide fuel cell to meet power and fresh water demand of a small town. The proposed system is simulated in MATLAB and validated with experimental data. Subsystems including solar field, reversible solid oxide fuel cell, organic Rankine cycle coupled with ejector cooling, and zero discharge multi effect desalination system are modeled and analyzed in design condition. The electrical and thermal efficiencies of photovoltaic thermal system are calculated as 9.82 % and 53.27 %, respectively, while photovoltaic cell's efficiency is 9.69 %. The organic Rankine cycle generates 451.5 kW and 1.31 MW for cooling and heating loads, respectively, with a net power of 450 kW. Freshwater production of desalination unit transpires at a rate of 9.6 kg/s in the effects, supplemented by an additional 13.5 kg/s in the spray evaporation tank, resulting in a calculated gain output ratio of 12.06 for the proposed system. The entire system has been examined during day and night throughout a year (taking one day for each month) with the assumption of system stability at every hour. Reversible solid oxide stacks switch between electrolyzer and fuel cell modes hourly, corresponding to hydrogen production or consumption across months. Monthly hydrogen dynamics are determined, showing peak production in June, minimal production in March, and negative values in January, February, November, and December. The total net hydrogen production over the entire year amounts to 22679 kg. The electrolyzer exhibits the highest power consumption, followed by the desalination cycle's electric heater, Reversible solid oxide cell's electric heater and evaporator. Peak power production during daylight is from the photovoltaic system linked to solar irradiance, while fuel cells maintain a consistent 5 MW generation during night. In fuel cell mode, the system attains 27.5 % overall efficiency in cold months and 25.8 % in warm months, while operating as an electrolyzer results in an overall efficiency ranging from 3.7 % to 4.1 %. The calculated annual average overall efficiency is 17.29 %.