A Low-Temperature Organic Rankine Cycle Integrated with Latent Heat Storage Harnessing Solar Thermal Energy for Power Generation

This study examines the performance of a system that integrates solar collectors, a latent heat thermal energy storage system (LHTS) based on phase change material (PCM), and an organic Rankine cycle for power generation. Evacuated tube collectors with a total area of 212.4 m(2) were utilized to harvest solar energy, and packed beds of encapsulated PCM, each with a nominal volume of 3.4 m(3), were proposed as the LHTS. The integrated system maintains a nominal power generation target of 1.4 kW. Numerical models were verified and validated with data from similar systems found in the literature. Performance metrics, including net power generation, operating time, stored energy, and system efficiency, were evaluated under favorable conditions for a selected summer week, and under unfavorable conditions for a chosen winter week. The results indicate that the use of PCM can extend the system's operating time by 7-8 h during the summer week, and 5-6 h during the winter week, with a power output variation of up to 10 % throughout the central core of the operational period. Remarkably, the use of PCM allows this extension of operating hours with an efficiency reduction of up to 0.1 % irrespective of seasonal conditions.