Enhancing performance by incorporating solar feedwater heating instead of steam bleeding of an existing steam power plant: energy and exergy analyses

This study presents energy and exergy analyses to improve the performance of a 500 MW thermal power plant by adding a direct solar feedwater heating system, rather than steam bleedings, resulting in a significant increase in energy efficiency. The energy efficiency increases from 44.33% to 48.50%, if off-bleeding is considered at the reheater inlet or at low- and intermediate-pressure turbines. A lower solar energy requirement of 134 MW is found when off-bleeding is established at the reheater inlet, but it demands an increase in temperature to 337.40°C. The approach enhances energy efficiency and introduces a new concept.