Energetic and Exergetic Analyses of a Direct Steam Generation Solar Thermal Power Plant in Cyprus

ABSTRACT: In recent decades, the threat of climate change and other environmental impacts of fossil fuels have reinforced interests in alternative and renewable energy sources for producing electricity. In this regard, solar thermal energy can be utilized in existing power generation plants as replacement for the heat produced by means of fossil fuels. The objective of this study is to investigate the energetic and exergetic feasibility of utilizing a solar thermal power plant in Cyprus. The analysis carried out is two-fold. First, the efficiency of each component of an existing steam power plant (Teknecik) is estimated using energy and exergy analyses. The results show that the boiler of this power plant has the highest irreversibility rate due to the combustion process of Fuel oil No.6 that happens in the boiler. In the second step, it is proposed to change the conventional power plant into a direct steam generation solar power plant. In this regard, parabolic trough collectors are used to generate superheated steam at 87 bars and 510˚C. Moreover, the energy and exergetic efficiency of each component of the new design has been estimated and compared with the results that obtained in the first part. The highest exergy losses occurred in the collectors while the receiver subsystem has the maximum energy losses. Furthermore, the average exergy efficiency of the solar field is 24% while the boiler average exergy efficiency is 50%. The outcome clarifies that a DSG power plant has poor energetic and exergetic feasibility due to the high rate of losses. Nevertheless, the exergy analysis shows the cause and the location of the losses which are worthwhile for optimizing and improving the solar field design. This can make the solar thermal power generation competitive with current technologies for producing electricity in large scales. Keywords: energy, exergy, steam power plant, solar thermal power plant, direct steam generation ……………………………………………………………………………………………………………………………………………………………………………………………………………………