Investigation of moisture transport in aluminium cooling panel plaster at cyclic water sorption regimes

The cooling ceiling panels made of the aluminium foam, with integrated circulation water distribution system, were developed. The properties of the aluminium foam (the relatively high thermal conductivity, the low bulk density) can predetermine these panels as the efficiently and rapidly reacting heat exchange elements. At the design of these cooling systems, it is necessary to prevent potential hygiene problems during their operation. The surface temperature of the panels must be higher than the dew point temperature and also higher than the temperature critical for growth of fungi. Therefore the temperature of cooling medium is limited and cannot fall below this critical value. To use the lower temperatures, the indoor air humidity, as well as the humidity of panel surface have to be maintained below the water vapour saturation values. This can be attained by the dehumidification devices in a room in a combination with the effectively designed hygroscopic panel surfaces. Therefore, the hygroscopic surface finishing plasters of the aluminium panels were developed. The simulation model of coupled 1D heat and moisture transport taking into account the sorption hysteresis in hygroscopic region was used to analyse the moisture response of the surface finishing plaster.