Energy Conversion Analysis of a Novel Solar Thermochemical System Coupled With Fuel Cells

Fossil fuels have been the main supply of power generation for use in manufacturing, transportation, residential and commercial sectors. However, environmentally adverse effects of fossil fuel conversion systems combined with pending shortage raise major concerns. As a promising approach to tackle these challenges, this paper presents a novel energy conversion system comprising of a solar thermal reactor coupled with hydrogen fuel cell and carbon fuel cell for electricity generation. The system uses concentrated solar energy for high temperature heat which upgrades the calorific value of the feedstock by 8%. The paper describes the components and characteristics of the proposed concept and models the energy flow of this system. A comparison based on unit mass feedstock supply is made with conventional Brayton cycles for electricity production. The results show that the extent of acetylene byproduct conversion in the solar reactor is of crucial importance to ensure competitiveness. Depending on the fuel cells efficiency and even more on the extent of byproduct formation, the results show that the overall chemical-to-electrical efficiency of this combined system ranges from 35 to 58%.