Transient numerical analysis of charging a heat accumulator in a combined heat and power plant

Abstract

This paper presents a technical description and characteristics of heat accumulation system operation in one of the Polish combined heat and power (CHP) plants. The total thermal capacity of the nonpressure hot water accumulator is 75 MWh. An important issue in the case of hot water tanks is thermal stratification caused by the difference in density between higher-temperature water, located in the top of the hot water storage tank and colder water in its bottom. The article presents the results of numerical analysis based on axial-symmetric model of hot water tank using Ansys Fluent software. Simulations with the Computational Fluid Dynamics (CFD) method were carried out for the process of charging the heat accumulator lasting 10 hours. The results were compared with the measurement data from the CHP plant.