Thermal behaviour of an active slab: experimental study for TABs applications

Abstract

The building sector presents considerable potential to have its energy consumption reduced. An alternative of current great interest is taking profit of the thermal inertia of the same structure of the building, through embedded pipes, for storing thermal energy generated when costs are lower and/or efficiency is higher, named “Thermal Activated Building Systems” (TABS). Energy accumulated is then dissipated when demand raises, seeking to ensure stable indoor comfort conditions while reducing the consumption of conventionally generated energy. The behaviour of these systems is determined by a number of operating parameters to be defined to ensure it operates in an optimal way, taking into consideration criteria such as heat flux dissipated, times of charge and discharge of the structure, position of the active slab, temperature of the fluid use inside the embedded pipes and ambient thermal conditions. It has been demonstrated that the study of the thermal behaviour of sand and gravel active slabs can be extrapolated to concrete, real slabs. This paper presents the experimental results obtained in slabs of 15 and 20 cm thickness, charged until reaching steady state. Then the work discusses the thermal behaviour of the slab for different water temperatures supplied to the pipes. Thus, it illustrates the possible experimental study of active slabs to predict the thermal behaviour of TABS in real applications.