The efficiency of steam production by the Parabolic Trough Collector PTC with the use of nanofluids in the region of Ouargla

Concentrated solar power plants (CSP) contribute to global production (at present) with a capacity of 400 MW, and by 2020 they will reach approximately 20 GW, then nearly 800 GW by 2050, This will prevent the emission of 32 million tons of CO2 annually in 2020, and rise to 1.2 billion tons in 2050, according to the International Greenpeace “Solar Thermal Electricity” 2016 report. Among all the concentrated solar power (CSP) technology available to date, Parabolic Trough Collector (PTC) is the most promising, cost-effective, and efficient solution to generating electrical power, as PTC plants contribute in terms of global production capacity by 73.58% of the overall capacity of concentrated solar power plants (CSP). PTC stations in the production of electricity depend on the generation of hot and pressurized steam that rotates the turbines and to increase the effectiveness of PTC in the production of steam, we use in this study nanofluids by adding copper nanomaterials in different proportions to improve the Thermal efficiency of PTC. We also studied the effect of the width of the PTC slot on the fluid temperature. And from it on the amount of steam produced. The results of the study showed that the Thermal efficiency increases with the increase in the ratio of copper nanomaterials in the water, as the temperature of outlet water reaches 98°C, for the ratio of nanomaterials, 20%, in order to water flow 0.01 Kg/s and display the aperture 3.5 m.

Constant-Volume Vapor-Liquid Equilibrium for Thermal Energy Storage: Proposal of a New Storage System for Concentrated Solar Power Plants

The development of thermal energy storage systems is key to increasing the deployability and reliability of concentrated solar power plants. Previous work from the authors studies the possibility of exploiting vapor-liquid phase change in closed and constant volumes as a thermal energy storage mechanism because of the higher heat transfer coefficients of the phenomenon with respect to solid-liquid phase change energy storage systems. The objective of this paper is to propose a new thermal energy storage condition based on vapor-liquid systems for concentrated solar power plants. The reference case of the Khi Solar One power plant in Upington, South Africa is taken. Results show that increasing the critical temperature of the storage fluid allows for increased temperature differences and higher volume-based energy storage, while the decrease of critical pressure allows lower mechanical stresses on the energy storage system. The use of high critical temperature fluids such as ethylene glycol allows for an increase of the volume-based energy storage of around 95% at same pressure conditions with respect to the base case. The use of low critical pressure siloxanes such as D6 results in a decrease of around 26% in the volume-based energy storage. The use of D6 on the other hand leads to a substantial decrease in the maximum pressure of the storage system, which drops from 8.2 MPa to 1 MPa, allowing the use of cheaper and less complex equipment. Both cases lead to a relevant increase in the maximum storage temperature, increased of 130 K and 55 K respectively.