Comparative Study of Using Water and R-134a as Cooling Medium in the Condenser of a Steam Power Plant

This paper presents a comparative analytical study of using water and R-134a as cooling medium in the condenser of a steam power plant (SPP). In this study, a shell-and-tube cross-flow heat exchanger has been considered. Because of its direct effect on cycle thermal efficiency, the condenser of the SPP has been continuously improved over the years. One of the ways of increasing the performance of a SPP is by reducing the condenser pressure and using low temperature cooling medium in the condenser. The lower the temperature of the cooling fluid circulating through the condenser tubes, the faster will be the steam condensation. This process increases the condensation rate as well as condenser heat transfer rate. Refrigerants have much lower temperatures and much higher heat transfer rates than water. In this comparative study of using R-134a or water as a cooling fluid in the condenser of a SPP, steam enters the shell side of a single-pass horizontal condenser and the condensate is collected at the bottom. Cooling fluid, “water or R-134a”, is fed into the tubes. The results of the analytical study indicated higher condensation rates and heat transfer for R-134a than water. Moreover, the exergetic and exergy efficiency analysis revealed that R-134a has higher values than water, which increase the power plant thermal efficiency and reduce the condenser size.