Comparison of entransy loss analysis and the first law of thermodynamics in the optimization of organic Rankine cycle coupled with parabolic trough collector.

The article focuses on optimizing an Organic Rankine Cycle (ORC) coupled with Parabolic Trough Collectors (PTC) for solar power generation using two objective functions: maximizing output power and maximizing entransy loss, a thermodynamic measure of heat transfer inefficiency. The study considers four working fluids—toluene, cyclohexane, hexamethyldisiloxane (MM), and water—across collector fluid inlet temperatures from 310 to 400 °C, employing a genetic algorithm in MATLAB for optimization. Results show that toluene yields higher power at lower temperatures (310–320 °C), while water outperforms others at higher temperatures (>330 °C); however, maximizing entransy loss does not correspond to maximum output power under the study's non-dumping and variable heat capacity conditions. Overall, optimizing for output power produces higher cycle and system efficiencies than optimizing for entransy loss, suggesting that traditional power maximization remains the preferred design approach for solar ORC-PTC systems under these conditions.