In the past years, European building developers, architects
and engineers are deciding more often to use a
radiant cooled ceiling to thermally condition spaces with
high cooling loads, as the experiences with cooled ceilings
are very persuasive w20x. About 10% of all new installa-
tions in German non-residential buildings mostly build-
ings for banks and insurance companies. are being built or
retrofitted with cooled ceilings to provide the best thermal
comfort w23x. When cooled ceilings are properly designed
and operated favorable operation costs and more usable
building space can be achieved as well w7x
Those advantages
when compared with all-air systems are provided
only by hydronic radiant cooled ceilings, which only remove
sensible cooling loads. Latent loads and pollutants
have to be removed by an additional ventilation system.
Basically, the windows and doors of a building can be
used to supply fresh air to the spaces w18x, but preferably,
mechanical ventilation should be used to always guarantee
an energy efficient air exchange rate w21x. For mechanical
ventilation, either displacement ventilation 2 or mixing
flow systems can be used, with a supply airflow reduced
according to the hygienical requirementsw2,8,10x.
A German survey w23x shows that about 10% of all
cooled ceiling applicationsby cooling area.rely on natural
ventilation, i.e., these were installed without any additional
mechanical ventilation system. Both displacement