Example of Thermal Energy Storage
In Förvaltningshuset, office building, 9 100 m2, Strängnäs, Sweden, the indoor temperature did not exceed 25 oC on a hot September day in year 1997 while only night cooling using outdoor air is installed. The night was very warm so the indoor temperature was not lower than 23,5 oC in the morning. The figure below illustrates that the room temperature has not increased by more than 1oC during the working day. The slabs are capable of storing most of the heat gains in the room despite them being heated by the supply air for more than six hours.
In order to store this amount of energy in the concrete slabs, tight false ceilings such as mineral boards cannot be covering 100% of the ceiling surface as that will reduce the storage capacity by 85-90%. Thick carpets shall also be avoided.
In many projects including the TermoDeck® system false ceilings or acoustic panels have been used. By placing them in certain ways the storage effect is not hindered very much at all:
- Cover maximum 40% of the ceiling surface area with acoustic panels
- Acoustical panels can be placed at a distance from the ceiling and from each other
- Hang the panels vertically
- Put the panels around the perimeter of the slabs and on the walls
- Metal false ceilings with openings of at least 40% do not hinder the room air to convect on the slab surface
The performance of the TermoDeck® system has worked as expected in projects with false ceilings as above.