Development and Performance Evaluation of High Temperature Concrete for Thermal Energy Storage for Solar Power Generation

Large-scale solar power generation becomes feasible using concentrated solar power plants, as the received heat is collected at high temperatures compatible with power cycle operations. The main drawback of solar power generation is the intermittent nature of available solar irradiation, which results in a mismatch between collected heat and electrical demand. Thermal energy storage (TES) systems are the options to resolve this problem by storing excess heat during high solar irradiance and releasing at off-sun conditions. Thermochemical energy storage (TCES) systems have the potential to store the solar energy at high temperatures suitable for CSP plants’ operations because of the higher energy density of the TCES materials than those used for sensible and latent heat storage options. In TCES, the heat is stored in the form of thermo-chemical energy using an endothermic reaction and is released by carrying out the reverse exothermic reaction. TCES using cobalt oxide redox (reduction/oxidation) reaction is selected for this study because of its unique features suitable for high temperature thermal energy storage. A reactor with the cylindrical fixed bed is considered, in which air flows through the bed during charging and discharging modes. Air is used as heat transfer fluid (HTF) and as the reactant gas supplying oxygen. Transient mass and energy transport equations are solved along with reaction kinetics equations using finite element method. Charging and discharging processes are investigated. The effect of geometrical and operational parameters including the material properties on overall storage and retrieval process has been studied. It was shown that the bed porosity plays a dominant role in the reactor performance. The increase in the bed porosity improves the reactor performance for both charging and discharging mode.

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Exergetic and Exergoeconomic Analyses of a Parabolic Trough Solar Power Generation System

Volume 1: Fuels, Combustion, and Material Handling; Combustion Turbines Combined Cycles; Boilers and Heat Recovery Steam Generators; Virtual Plant and Cyber-Physical Systems; Plant Development and Construction; Renewable Energy Systems ◽

10.1115/power2018-7189 ◽

2018 ◽

Author(s):

Anming Wang ◽

Ming Liu ◽

Xiaoqu Han ◽

Jiping Liu

Keyword(s):

Power Generation ◽

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Solar Power ◽

Generation System ◽

Parabolic Trough ◽

Solar Power Generation ◽

Power Generation System ◽

Solar Field

As concentrating solar power technologies moves to maturity progressively, large-scale solar thermal power plants have gained increasing attention. The exergetic and exergoeconomic analyses allow indicating energy degradation of the component quantitatively and establishing the monetary value to all material and energy flows. Therefore, they have strong theoretical implications to the system optimization. A thermodynamic simulation model of a 50 MW parabolic trough solar power generation system and the related exergetic and exergoeconomic analyses were presented in this paper. The results of exergetic analysis showed that the component of the lowest exergy efficiency was solar field, and the efficiency only had approximate 22%. Moreover, the exergy efficiencies of thermal energy storage and power block were about 81% and 58% respectively. According to the exergoeconomic analysis, the exergoeconomic cost of electricity and output thermal energy of solar field and thermal energy storage varied respectively in the ranges of 0.1277–0.1322 $/kWh, 0.0427–0.0503 $/kWh, and 0.0977–0.1074 $/kWh when thermal energy storage capacity ranged from 4 hours to 12 hours.

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