Thermodynamic analysis of parabolic trough and heliostat field solar collectors integrated with a Rankine cycle for cogeneration of electricity and heat

Abstract

Nowadays the production of electricity still relies heavily on the use of fossil fuels and is a main factor in environmental pollution. Therefore, clean alternative sources are needed for the production of electricity. In recent years, the use of renewable energy has become more prevalent in our everyday lives due to an increased environmental awareness worldwide. Solar energy emanating from the sun is used in agriculture, thermal heating, and electricity production. This study proposes a model that integrates a solar harvesting system of collectors that heat up a heat transfer fluid into a conventional Rankine cycle for the production of electricity and thermal power. In this regard, a thermodynamic analysis of the proposed model is performed to evaluate and improve its performance. The analysis consists of an assessment of energy equations extracted from literature and theory books for each subsystem; the solar collectors (a parabolic trough and a heliostat field); and the Rankine cycle. These equations are used to simulate the performance of the overall system under constant solar irradiation. Moreover, a parametric study is carried out to determine the effect of various design and operation parameters on the overall efficiency and power output. Furthermore, a comparative analysis of the parabolic trough and the heliostat field is presented in order to determine the optimum option to couple with the proposed model. The different operating conditions include several solar irradiation intensities, geometric values of the collectors, mass flow rates of the heat transfer fluids, and temperature values. The results show that the heliostat field achieves a better performance in comparison to the parabolic trough.