Numerical modeling of transient heat transfer in heat storage unit with channel structure

Abstract The subject of the paper is a heat storage unit made of repeatable modules that are used in solar installations for heat accumulation. The accumulator may be a separate unit, or it may be a building wall insulated on the inner and outer surfaces. It is a heat accumulator with dynamic discharge using of forced air flow through the channels. The transient temperature field in the walls of the channels was modeled using control volume based finite element method (CVFEM), and the heat transfer in the flowing air was modeled by finite volume method (FVM). The CVFEM was chosen for the construction of a model of the heat storage unit, due to the ease of modeling a solid filling of a heat storage unit with a complex shape. In the numerical model of the heat storage unit, it was taken into account that air flow in the heat storage unit can be laminar, transitional or turbulent. The finite volume method was improved to obtain accurate air temperature distribution even with a small number of finite volumes. The results of calculations of the heat storage unit obtained using the proposed numerical model were compared with the results of CFD simulation and experimental data.