Numerical evaluation of energy system based on Fresnel concentrating solar collector, Stirling engine, and thermoelectric generator with electrical energy storage

The purpose of this paper is to present a conceptual study of energy cycle performance consisting of two subsystems of electricity generation and storage. The introduced cycle is based on a linear Fresnel reflector (LFR) technology with a Stirling engine and thermoelectric generator (TG) to generate electricity and pumped-hydro-compressed air (PHCA) technology to store energy. Solar energy is converted into thermal energy through parabolic mirrors of the Fresnel and heating the fluid inside the collector. The resulting heat energy provides the required heat duty of the engine. This heat enters the Stirling cycle as input heat, and the mechanical energy convert into electricity. In addition, TG is thermally connected to the engine exhaust to generate additional electric energy. Then, the energy produced from the power generation subsystem is stored by the energy storage subsystem. Although many works had been done on the integrating of various solar thermal collectors and intermediate and/or downstream cycles, efforts had not been created to develop research on the combination of LFR, Stirling engine, TG, and PHCA system. Results showed that the power generation subsystem could generate 1.46 kW of electricity. The share of Stirling engine and TG in electricity generation was 72.6% and 27.4%, respectively. In addition, the power generation and energy storage efficiencies were 39.52% and 63.75%, respectively. Two different cases are offered for the design of the Fresnel solar field based on the useful power obtained.