Free-cooling adiabatic ahu
18th November 2013
Airedale International Air Conditioning is to extend its range to include an indirect, free-cooling, adiabatic air handling unit.
With production launch set for spring 2014, the AireFlow AHU uses fresh air as the predominant cooling source, significantly reducing operational costs. Being an indirect system, it also eliminates the risk of contaminated air entering the data centre.
The AireFlow will be available in five footprints between 100 and 300kW, each with two separate case sizes depending on whether roof or wall mounted connection is required.
High efficiency EC centrifugal backward-curved fans draw return air from the data centre through the heat exchanger. Cooler air from the outside ambient is drawn through a separate air path within the heat exchanger, also by EC plug fans. This temperature difference drives heat exchange, with the supply temperature being managed through modulation of the ambient air flow rate.
At any point in the year, as climatic conditions dictate, moisture is added to the warm outdoor air to lower the dry bulb temperature. A typical UK peak summer day for example may have a dry bulb of 35°C with a wet bulb temperature of 21°C. By fully saturating the air, the dry bulb temperature can be reduced to 21°C. This lower air temperature is then used as a cooling medium and, based on London ambient temperatures, could achieve AHSRAE recommended conditions using 100% free cooling.
In more challenging environments, an optional mechanical cooling module will ‘top-up’ the cooling capacity with a partial DX supplementary cooling section.
In addition to its reduced footprint, an optional integrated fresh air inlet unit provides added installation benefits. Air flow and pressure monitoring also allows filter and fan performance to be managed.
