Center for the Built Environment

Radiant slab systems have the potential to achieve significant energy savings, yet, when applied in the ceiling (e.g., thermally activated building system) the exposed concrete may also create acoustical challenges due to the high reflectivity of the hard surface. Balancing all of the building indoor environmental quality factors is important in the design of an effective workspace for the occupants, and so we need to consider the interactions between thermal and acoustic comfort. We assessed the cooling capacity in a hydronic test chamber and the sound absorption in a reverberation chamber to study the effects, for an office room, of different coverage areas of free-hanging acoustical clouds below a radiant chilled ceiling. The cooling experiments showed that for 47% cloud coverage of the ceiling area, we measured only an 11% reduction in cooling capacity caused by the blockage of radiant exchange between the ceiling and the room. The acoustical results showed that if the cloud covered 30% of the ceiling in a private office or 50% in an open plan office, acceptable sound absorption at the ceiling was achieved. We showed that good acoustic quality can be achieved with only a minor reduction of cooling capacity.