New advances in cooling and drying technologies for healthy buildings

Researchers at Engineering school of Canton de Vaud (Switzerland) are developing a new technique that will enable to make cooling ceilings free of condensation risk.

Nowadays it is well accepted that radiant cooling ceilings provide a better comfort and normally cause a smaller energy demand than conventional convective air conditioning systems. Nevertheless, cooling panels are only seldom taken into operation without a control of the air condition, because the dew-point could increase over the panels temperature.
In order to solve this problem, researchers at Engineering school of Canton de Vaud Institute of thermodynamic have developed the Thermoelectric Ceiling Condenser (TCC), a technique that enables to avoid any condensation on the cooling panels.
The TCC system consists of a heat exchanger, which is cooled by Peltier elements that are contacted with the ceiling panels to keep the condensing unit at a low temperature. The pumped heat is transferred into the ceiling to a surface temperature above the dew-point. The control of the surface temperature is achieved by regulating the mass flow through the system.
A prototype was designed, built and mounted in direct contact to a conventional cooling ceiling. Tests have been performed in a full-scale climatic chamber. The main objective of avoiding condensation on the panels in the downstream direction is clearly achieved. The total cooling power of the combined system - consisting of cooling panels and TCC units - is 20 % higher compared to the cooling power of the panels, which are operated without TCC units.
Our research efforts prove that the full set-up (panels and TCC units) also allows a reduction of the installed power of the air-conditioning system. The reason is the advantage of the ability to control the temperature in the vicinity of the dew-point. This leads to an improvement of the indoor comfort:,- Less noises,- Less draughts,- Less risks of dry eyes or/and dry throats.
In numerous cases it will be even possible to replace the entire (convective) air conditioning system. The following advantages are expected:,- Perfect adaptation of system to building retrofits (no air ducts, only water piping system) ,- Less cleaning duty, very healthy system (no air ducts),- Substantial energy savings (use of low exergy sources),- Less restrictions on window opening,- No maintenance, very high reliability (the TCC system has no moving part).,Dr Gilles COURRET,Ingenieur R&D,Ecole d'Ingenieurs du Canton de Vaud,Institut de Genie Thermique,Route de Cheseaux, 1,Case postale,CH-1401 Yverdon-les-bains,Tel.:[phone],Fax:[phone],www.eivd.ch

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