HVAC Air Systems: Low Pressure Drop Air Systems


Fan energy can account for 20 to 40% of total cleanroom energy use. Fan energy use is directly proportional to the pressure drop that the fan is pushing air through. Thus, the more restrictive the supply system, the higher the pressure drop, and the higher the fan energy use. Strategies for lowering the pressure drop include lower face velocity air handling units, low pressure drop filters, optimized design of ducting and air paths, including open plenum and centralized air handler types of configurations. Low pressure drop designs are applicable to all fan systems from recirculation air handler systems to makeup air handlers. Other benefits of low pressure drop systems are less noise, more effective dehumidification, better filter effectiveness, and in some cases lower total first cost (when avoided electrical and noise abatement equipment is included in the cost analysis).