The aim of this study was to conduct thermodynamic and economic analyses of a concentrated solar power (CSP) plant to drive a supercritical CO₂ recompression Brayton cycle. The objectives were to assess the system viability in a location of moderate-to-high temperature solar availability to sCO₂ power block and to investigate the role of thermal energy storage with 4, 8, 12, and 16 hours of storage to increase the solar share and the yearly energy generating capacity. A case study of system optimization and evaluation is presented of a city in Saudi Arabia. To achieve the highest energy production per unit cost, the heliostat geometry design integrated with a sCO2 Brayton cycle with a molten salt thermal energy storage (TES) dispatch system and corresponding operating parameters are optimized. A solar power tower (SPT) is a type of CSP system that is of particular interest in this research because it can operate at relatively high temperatures. The present SPT-TES field comprises of heliostat field mirrors, a solar tower, a receiver, heat exchangers, and two molten-salt TES tanks. The main thermo economic indicators are the capacity factor and the levelized cost of electricity (LCOE). The findings indicate that SPT-TES with a supercritical CO₂ power cycle is economically viable with 12 hours thermal storage using molten salt. The results also show that integrating of 12 hours-TES with a SPT has a high positive impact on the capacity factor of 60% at the optimum LCOE of $0.1078/kWh.

In this paper, a new design for the flow channels is presented, and a parametric study of the proton exchange membrane (PEM) fuel cell is conducted in order to investigate the effect of the new flow channels, as well as different operating parameters, on the efficiency and energy output of the cell. Design parameters are selected based on studies presented in the literature to build a physical and practical model. With the new design of the flow channels, it is noticed that the cell efficiency increases from 33.8% to 47.7% if the temperature of the cell is increased. The power output of the cell increases from 2.6 to 282.5 W when the cell temperature and the current density are increased. Moreover, decrease in the efficiency of the cell ranges from 45.5% to 28.4% with the increase in the current density and membrane thickness. Based on the analytical model, design parameters were selected to manufacture a fuel cell that has a power output of 175 W and an efficiency of 35% running at 353 K and 3 bar, with an effective membrane area of 450 cm². Experiments are conducted to investigate the effect of newly designed flow channels on pressure distribution. It is found that when hydrogen is supplied from both inlets, pressure across the channels become symmetric and, therefore increasing the power output. This study reveals that, with the proper choice of design parameters, a PEM fuel cell is an attractive economical, efficient, and environmental solution when compared with conventional systems of power generation such as gas turbines. Copyright © 2011 John Wiley & Sons, Ltd.