Enhancement in thermodynamic cycle condensation of a coal-fired power plant by integrating a PCM heat storage tank into the indirect dry cooling system

Abstract

This paper proposed a novel cooling system that combines a phase change material (PCM) with an indirect dry cooling system to enhance exhaust steam condensation of the Rankine cycle for a coal-fired power plant (CFPP), especially in high ambient temperature conditions. A PCM heat storage tank (PCMHST) is embedded in series between the natural draft dry cooling tower (NDDCT) and condenser to realize peak and valley shifting of cooling capacity, and RT35HC is selected as the PCM. During discharging process of the PCMHST, RT35HC is chilled by low-temperature circulating water; during charging process of the PCMHST, the circulating water is cooled in the PCMHST and NDDCT. This paper first reveals the effects of cooling load distribution in the novel cooling system on the CFPP operating economy during charging and discharging process. In addition, the PCMHST in series before the tower can reduce the circulating water temperature more efficiently than that in series behind the tower. Results show that integrating a PCMHST can reduce the coal consumption of the CFPP by 5325 kg within a complete back pressure regulation process.

Keywords

• coal-fired power plant
• dry cooling tower
• cooling performance
• latent heat storage
• thermal economy evaluation