On the heat storage in Solar Updraft Tower collectors – Water bags

The goal of this study is to analyze particularly the sensible heat storage physical process in a Solar Updraft Tower collector taking into account the transient heat transfer in ground through conduction, convection and solar radiation and the use of water bags. Simulations were carried out varying the thickness of some water bags sets with and without insulation regarding thermal stratification effect. Results disclosed that thicker water bags can reduce more efficiently the daily temperature spam and thermal stratification is an import thermal effect. Water bags alone are however not enough to break efficiently heat peaks.

► We model mathematically a solar chimney ground thermal storage system.
► We simulate a ground thermal storage system under constant boundary conditions.
► The thermal stratification effect was described and included in model.
► We simulate different sets (thickness and insulation setup) of water bags.
► We found out that thicker water bags support shorter temperature spams.