1.5.4 Air-Side Economizers
Reduce building cooling loads by using cool outside air in lieu of reconditioned return air.
Economizers are exterior hoods at the outside of AHU that bring in substantial amounts of outside air to cool the building when conditions permit. Instead of having to cool return air, these appliances lead to much more efficient energy use by drawing in cooler outside air.
Air-side economizers can be used in conjunction with evaporative coolers in hot and dry climates. Dehumidification is required in humid climates.
The cost and savings of air-side economizers varies depending on climate. They are most economical, and often required by code, in temperate and cool climates.
Reduced energy use through reduced cooling loads; increased ventilation. Economizers, when coupled with direct/indirect evaporative cooling, can go a long way to reduce electricity consumption
Economizers require thorough commissioning to assure their proper working order. According to Mark Frankel, Technical Director of the New Building Institute, 70% of economizers installed in the U.S. don’t work properly because they haven’t been commissioned and maintained periodically, as required. Air-side economizers are most effective in cool and/or dry climates. Dehumidification is required in humid climates, and the energy savings may not be sufficient to justify the cost in hot and humid climates.
1.7.7 Evaporative Cooling