Numerical simulation of turbulent coupled heat transfer in a Trombe wall subjected to periodic thermal excitations

Abstract

The authors of the present work numerically investigated the turbulent coupled heat transfer occurring in three types of Trombe walls. They are mainly made of a concrete or water column surrounded by solid partitions. They are equipped with single or double glazing and a removable solar film to avoid overheating during the summer season. The three systems are exposed to a variable solar flux and exchange by convection and radiation with the internal and external mediums through the lateral surfaces. The vertical heat transfer is neglected by prescribing a zero flux on the extreme horizontal surfaces. The thermal behavior of the three types was simulated using a mathematical model based on the principle of conservation of mass, momentum, and energy in laminar and turbulent regimes. The outdoor ambient temperature and solar radiation are modeled by sinusoidal functions whose amplitude and mean are chosen to represent the temperate to warm climate of Morocco. Simulation results of the three systems were compared and showed that the water Trombe wall with double glazing is the best performing configuration. Indeed, its efficiency can reach 46 % and the time lag between the incoming heat flux and solar radiation can go up to 4h49min for winter and 7h23min for summer. On the other hand, the water Trombe wall attenuates the internal temperature variations with a decrement factor of 0.28 when the solar film is removed and 0.31 in the opposite case. Furthermore, the authors examined the response of this system to variations in the water column width, the external surface emissivity, and the conductivity of solid partitions.