Cooling effect during direct air humidification
Adiabatic evaporative cooling
An interesting and economic effect of the DRAABE direct room air humidification for some special applications is lowering the room temperature by adiabatic evaporation cooling. The complete absorption of the micro-fine, atomised water droplets in the air causes heat to be drawn from the room. The principle of adiabatic evaporation cooling can be likened to perspiration. Beads of perspiration evaporate on the skin. The heat this requires is drawn from the atmosphere. The skin cools down.
Air-conditioning may be able to be replaced
The adiabatic cooling effect through air humidification can support the use of air-conditioning and depending on the local conditions even replace it. An average reduction of room temperature of between 2°C and 5°C is possible. For each kilogram of water that evaporates per hour in the air as a result of nozzle humidification, a cooling capacity of 640 W can be achieved. If converted for an air humidification system with a capacity of 100 kg/h, this will result in a cooling output of 64 kW.
When compared with the energy cost for the high-pressure nozzle air humidification high-pressure pumps of 0.6 kW, the energy balance of the adiabatic cooling comes in highly positive and economically attractive.
Free cooling with outside air, as in the example of Facebook
Facebook uses the DRAABE high-pressure nozzle system ML Flex to cool the server halls and ensure optimum humidity at their Luleå location in Northwest Sweden. Cooling is achieved by combining direct free cooling via a controlled external air intake with the evaporative cooling of the ML Flex air humidification system:
Outside the server rooms, combination with direct free cooling (external air) is the most efficient way of cooling. In order to achieve the maximum cooling effect, the external air is led into “air collection rooms”, where it is then humidified and cooled using high-pressure nozzles. From here, the cold air flows directly into the cold aisles of the server racks. The DRAABE ML Flex system is especially suited for this solution thanks to its flexible design and is used, for instance, in the Facebook computer centre in Sweden.