Working principle of the Chilled Water Wall :

 

In a closed system, water flows across a vertical wall component placed inside the room, forming a liquid film on the component’s surface. Without cooling, the water will evaporate and humidify the indoor air. In the winter months, this will significantly contribute to improving comfort in dry indoor spaces. In summer, however, a chiller cools the water to temperatures below 10 °C.

 

The great temperature difference between the indoor air and the water ensures efficient cooling while  dehumidifying the indoor air.

 

If the water-film temperature remains below the dew point temperature of the indoor air, the indoor air humidity condenses at the water film and is discharged into the collecting basin. Excess water flows off through an overrun and can be collected for further use, if required.

 

Advantages over other systems :

 

Conventional air conditioners circulate cold and dry air. Though this type of air-based air conditioning is widely used, it is often criticized as being noisy and uncomfortable.

 

As alternative solutions, water-based cooling elements (such as large chilled ceilings) or cooling techniques with thermally activated building components have become established in the market. The advantage of these systems lies in their dual mode of action: the circulating air flow is cooled while a sink is created for the longwave radiation exchange with occupants and objects present inside the space. All this is achieved without causing noise or uncomfortable air draughts.

 

With these systems, however, the cooling power per unit area is limited. Contrary to the CWW, they are not suited for dehumidifying the indoor air, because the surface temperature of the cooling elements must not be reduced too radically in order to prevent condensation and mould formation.

 

The main benefit of the CWW is due to the fact that it can be operated at significantly lower temperatures without any problems. This will not only multiply the cooling power but also allow for effective dehumidification. Due to the long-wave radiation exchange with the chilled surface of the CWW and the reduced indoor air humidity, air  temperatures inside the space will be perceived as comfortable even if they exceed the usual comfort temperature by several degrees. In this way, the Chilled Water Wall ensures efficient air conditioning of buildings and saves energy, too.