A Comprehensive analysis of energy, exergy, economic and environment on integrated solarcombined cycle with various HTFs and thermal storage

Abstract

Energy and exergy analysis are considered as important tools for the thermodynamic assessment of any power plant. The utilization of solar energy in electricity generation is progressively increasing day by day due to various issues associated with conventional power plants. In recent times, solar systems in integration with conventional power plants have emerged as popular and optimal solution. The current integrated solar combined cycle (ISCC) involves integrating a 15 MW linear Fresnel reflector with the existing 328.10 MW combined cycle power plant situated in North India. The proposed study examined the thermodynamic performance (energy and exergy) of ISCC and cascade thermal storage. The exergy loss in solar system, combined cycle, and thermal storage is quantified, followed by a comparative analysis of the impact of integrating the solar system and thermal storage on the exergy loss within the combined cycle plant. The results indicate that the collector-receiver experience the highest exergy loss at 69.41%, which is further reduced by 1.82% and 3.39% by employing therminol oil and molten salt, respectively, in thermal storage within the solar system. Additionally, integration of solar system & thermal storage with conventional system showed improvement in second law efficiency. The overall exegetic efficiency of the power system is improved by 1.38% and 3.12% utilizing molten salt as HTF with two-tank system and cascade TES respectively. CO2 emissions are reduced by 97,020 tons per annum with molten salt, which serves as a superior HTF compared to water. Cascade TES systems reduce a greater amount of CO2 emissions compared to two-tank TES systems, amounting to 172,260 tons per annum.