Optimizing Electric Humidifier Operation with an Air Side Economizer

摘要

Air side economizer cycle is a control scheme that isoften used in WAC systems to reduce coolingenergy consumption by introducing variablequantities of ambient air into a conditioned space tosatisfy the space cooling load (free cooling).Humidifiers are used to maintain the pre-sethumidity levels in a conditioned space byintroducing steam or atomized water into the space.An WAC system containing both electrichumidifier and air side economizer cycle can appearto be energy efficient, but has the potential of beinginefficient due to lack of proper controls. Theeconomizer, which often operates independently ofthe humidifier, introduces large quantities of cooland dry ambient air into the space to reduce themechanical cooling energy, but because of theenvironmental requirement of the space, the air hasto be humidified. The humidification energy couldoffset the energy savings from the reduction inmechanical cooling energy.The solution for this potential problem is a controlscheme that makes the operation of the economizerand electric humidifier interdependent. The controlscheme will use ambient conditions and spaceenvironmental requirements to calculate theappropriate amount of outside air that theeconomizer should draw into the space. The controlscheme can be implemented through a Direct DigitalControl system.