Modélisation d'un ballon de stockage thermique

Abstract

The stratification in a Storage tank is the key for the good functioning of all installation aiming at meeting thermal needs (production of sanitary hot water, home heating). The work undertaken in this dissertation focuses on the modeling of a storage tank in order to understand better the thermal behavior of the latter one. The impact of many parameters (water injection debit, the nature and the thickness of the insulation, usage of a heat exchanger or an electrical booster) on the temporal evolution of the temperature (in case of charge and of discharge) in the tank was examined. The modeling of the stratification is undertaken by subdividing the tank into N (20) layers. An energy and a masse balance is drawn up in every node. The system of the global equations is resolved by the Crank-Nicolson method. The results obtained show clearly that the last layer heats faster, especially as the injection debit is elevated and the tank homogenization time becomes shorter. Besides, it appears that a good isolation allows to minimize the losses, and to avoid the creation of convective current, which could degrade the stratification. The comparison of the numerical results obtained in this work with those of the literature shows a good agreement.