S Ethane Brayton Power Conversion Systems for Concentrated Solar Power Plant

Abstract

The objective of this investigation is the comparison between supercritical ethane (sethane, C2H6) and supercritical carbon dioxide (sCO2) Brayton power cycles for linefocusing concentrated solar power plants (CSP). In this study, CSP are analyzed with linear solar collectors (parabolic trough (PTC) or linear Fresnel (LF)), direct molten salt (MS), or direct steam generation (DSG) as heat transfer fluids (HTF), and four supercritical Brayton power cycles configurations: simple Brayton cycle (SB), recompression cycle (RC), partial cooling with recompression cycle (PCRC), and recompression with main compression intercooling cycle (RCMCI). All Brayton power cycles were assessed with two working fluids: sCO2 and sethane. As a main result, we confirmed that sethane Brayton power cycles provide better net plant performance than sCO2 cycles for turbine inlet temperatures (TITs) from 300 آ°C to 550 آ°C. As an example, the sethane RCMCI plant configuration net efficiency is ∼42.11% for TIT = 400 آ°C, and with sCO2 the plant performance is ∼40%. The CSP Brayton power plants were also compared with another stateoftheart CSP with DSG in linear solar collectors and a subcritical water Rankine power cycle with direct reheating (DRH), and a maximum plant performance between ∼40% and 41% (TIT = 550 آ°C).