Work

Thermo-economic assessment of an innovative power cycle for medium-temperature concentrated solar power plants

Year: 2025

Type: article

Abstract: Medium-temperature parabolic-trough concentrated solar power (CSP) plants still rely mainly on superheated steam-Rankine cycles, which limit efficiency improvements and cost reductions. This study proposes and evaluates a propane-based hybrid Rankine–Brayton (HRB) power cycle as an alternative for CSP plants operating below 400 °C. A parametric thermodynamic analysis was first performed to identify efficiency optima for several reference configurations under identical heat-source conditions, including steam-Rankine, organic Rankine (toluene), supercritical CO2 recompression Brayton, and HRB–isobutane cycles. In the standardized comparison, the solar field and thermal energy storage (TES) were held constant, and the total design-point heat-exchanger size of the power block was fixed across cycles; a genetic algorithm optimized its distribution among components to maximize net power without relying on component-cost assumptions. Annual simulations were then performed using hourly meteorological and electricity-price data for Seville, with revenue-maximizing dispatch. Results show that HRB–propane achieves a similar annual energy yield to the steam-Rankine baseline while delivering 1.3% higher revenue and reducing power-block costs by 9.8–28.6%, thereby lowering LCOE by 1.2–4.1%. Compared with ORC–toluene, HRB–propane attains comparable profitability while exhibiting lower cycle pressure ratios and above-atmospheric condensing conditions, reducing air-ingress risk. These findings suggest that propane-based HRB cycles can improve the techno-economic performance of CSP plants below 400 °C, supporting their consideration for next-generation solar-thermal systems.

Source: Energy Conversion and Management X

DOI: 10.1016/j.ecmx.2025.101430

Authors: Antonio J. Subires, Antonio Rovira, Marta Muñoz

Institution: Universidad Nacional de Educación a Distancia

Language: English

Topic: Thermodynamic and Exergetic Analyses of Power and Cooling Systems

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Climate action, Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,170