Control Strategies of an Adaptive Glazing
Abstract
Controlling the solar transmittance of glazed office buildings that are facing the sun is not only crucial to ensure high thermal comfort but also to minimize the cooling and heating demand of the building. Often the solar and visual transmittance of glazing installed in high office buildings is constant, as adjustable external shading elements are not possible to install, because of maintenance issues. Within the research project titled Fluidglass, a new glazing will be developed that has fluid chambers, which can be circulated and colored, to control the solar and visual transmittance and to collect heat in the fluid. This paper presents an assessment of the different control strategies that set the concentration of the colorant in the fluid chamber of the glazing. The assessment shows that certain control strategies have high potential for reducing the energy demand for heating and cooling depending on the locations (Munich 20-30%, Madrid 50-70%, Dubai 50-60%). However, they can also causes an increase of the electricity demand for lighting, which needs to be considered in the further development. In general, control strategies that only consider the solar irradiation are less promising than controls that also take the interior temperature into account. The results for controls that also respect the thermal comfort based on a Predicted Mean Vote index (PMV) can achieve low energy demand, presuming that a deviation from the highest level of comfort is acceptable. At this stage of research, none of the studied control strategies shows to be optimal for all climate conditions to achieve highest energy reductions. Further research is necessary in the development of a control strategy that can universally be applied.