Simulation of an organic rankine cycle driven by solar energy based on the absorptance of NFT and PYROMARK coatings in a parabolic trough collector

Abstract

This study analyzes the performance of an Organic Rankine Cycle (ORC) with a storage tank (ST) and powered by solar energy, applying NFT and Pyromark coatings in a parabolic trough collector (PTC) and how they are affected due to the decrease in absorptivity due to continuous use over time. The objective is to compare the efficiency of the PTC, the heat transmitted to the ORC, the net electrical energy production and the heat expelled by the ORC condenser. Between 1:00 p.m. and 7:30 p.m., the results indicate that the NFT coating showed the best performance, reaching an average efficiency of 60.8% in the absorption of useful heat, equivalent to 49.89 kW, this allowed an average net generation of electrical energy of 13.20 kW. In addition, the degradation of the coating over time was 0.23%. On the other hand, the PYRO coating presented an average efficiency of 59%, with a net production of electrical energy of 12.83 kW, which represents a reduction of 3.65% compared to the NFT. If the effect of time is considered, this difference increases to 5.43%, indicating that the performance of the PYRO coating has decreased by 1.78% due to the loss of absorptivity effect. The simulation was carried out for a full day (July 16, 2024), using meteorological data from the town of Dos Hermanas, Spain and was carried out by developing a proprietary algorithm in MATLAB.