Feasibility analysis of a solar field for a closed unfired Joule-Brayton cycle

A solar tower for a closed unfired Joule-Brayton cycle is considered. An analysis for four different plants rated power levels is performed. The system here analyzed comprises an intercooled and regenerated gas turbine engine, a concentrating solar tower with pressurized volumetric receiver and a heat exchanger to perform cooling of the working fluid, allowing its recirculation. The plant scheme enables an output adjustment, using an auxiliary compressor. A constant value of the solar receiver outlet temperature approximately of 800 degrees C, without use of fuel, in a large range of power, is obtained, guaranteeing a net thermal-to-electric efficiency around 40%. Thermoflex (c) has been used for the thermodynamics analysis and WinDelsol for solar field design and simulation (heliostat field and receiver). For the purposes of this work, it is assumed that the plant is located in Seville, Spain, with an annual direct normal irradiation (DNI) of 2,068 kWh/m(2).