Energetic and exergoeconomic analysis of different configurations of power and hydrogen generation systems using solar based organic Rankine cycle and PEM electrolyzer

Fossil fuels limitations and their environmental problems, forces finding a stable, clean and easy to store and transport energy source. Hydrogen produced by renewable energy has the above-mentioned advantages. In this manner the input energy for hydrogen production is provided from renewable resources. despite of its cost and low energy ratio solar energy is still considered as one of the best renewable methods for hydrogen production. ORC is a very suitable option for using low and medium temperature heat sources such as solar energy. In this research, energy, exergy and exergy-economic analysis for different configurations of power and hydrogen cogeneration systems using solar based ORC and PEM electrolyzer is implemented and results compared in different conditions in EES. Parametric analysis has been applied and the best cycle conditions have been obtained and analyzed in terms of energy, exergy and exergeoeconomics. The main results of the research showed that double-pressurization of the ORC, despite of reducing the process cost, has not a significant thermodynamic efficiency due to the increase in exergy losses (about 12 % in the range of condenser temperature changes and 37 % in the range of solar fluid inlet temperature changes) compared to the power and hydrogen cogeneration system with the simple ORC. Also, adding an intermediate heat exchanger to the existing ORC in the power and hydrogen cogeneration system, while maintaining and sometimes increasing the thermodynamic efficiency compared to the simple cycle, in some ranges of changes in the functional parameters of the cogeneration cycle, leads to a reduction in the cost of power production compared to the cycles based on the simple ORC (for example, between 1 % and 22 % cost reduction over the range of turbine inlet pressure changes), which is very significant.