Exergy and Thermoeconomic Analyses of Central Receiver Concentrated Solar Plants Using Air as Heat Transfer Fluid

Abstract

Abstract:The latest developments in solar technologies demonstrated that the solar central receiver configuration is the most promising application among concentrated solar power (CSP) plants. In CSPs solar-heated air can be used as the working fluid in a Brayton thermal cycle and as the heat transfer fluid for a Rankine thermal cycle as an alternative to more traditional working fluids thereby reducing maintenance operations and providing the power section with a higher degree of flexibility To supply thermal needs when the solar source is unavailable, an auxiliary burner is requested. This configuration is adopted in the Julich CSP (J-CSP) plant, operating in Germany and characterized by a nominal power of 1.5 MW, the heat transfer fluid (HTF) is air which is heated in the solar tower and used to produce steam for the bottoming Rankine cycle. In this paper, the J-CSP plant with thermal energy storage has been compared with a hybrid CSP plant (H-CSP) using air as the working fluid. Thermodynamic and economic performances of all the simulated plants have been evaluated by applying both exergy analysis and thermoeconomic analysis (TA) to determine the yearly average operation at nominal conditions. The exergy destructions and structure as well as the exergoeconomic costs of products have been derived for all the components of the plants. Based on the obtained results, the thermoeconomic design evaluation and optimization of the plants has been performed, allowing for improvement of the thermodynamic and economic efficiency of the systems as well as decreasing the exergy and exergoeconomic cost of their products.

Concentrating Solar Power Technologies

“…Costs are expected to decline in the near future due to various pilot projects currently underway in this field being validated and implemented on a large scale (including energy storage solutions). Figure 6 shows a country ranking on total renewable energy production capacity as of the end of 2017 [68]. From Figure 6, it can be seen, that the countries with the largest renewable energy production are China, the US and Brazil, followed by Germany and India.…”

Thermophysical Properties Experimentally Tested for NaCl-KCl-MgCl2 Eutectic Molten Salt as a Next-Generation High-Temperature Heat Transfer Fluids in Concentrated Solar Power Systems

“…This means that the HTF needs high density and heat capacity and also should have relatively low cost and large reserve available in nature. Low-cost heat-transfer fluids such as water [10], air [11], and supercritical CO 2 [12,13] cannot meet the requirement for energy storage at high temperatures. Materials like thermal conductive oils [14,15], molten salts, and liquid metals [16] have been screened comprehensively for HTF and thermal storage media.…”

Optimization of a Heliostat Field by Multiobjective Particle Swarm Optimization (MOPSO) Algorithm Based on Energy, Exergy, and Economic Point of Views

“…A good agreement was obtained when comparing the results of this study with those of the existing heliostat layout. The exergy and thermo-economic study of a solar power plant with a central receiver were conducted by Toro et al [15]. A thermodynamic and economic evaluation and optimization of this solar power plant were conducted to obtain the best exergy and economic efficiencies of the systems, reducing the exergy destruction and the exergoeconomic cost of the produced power.…”