Airside economizers are simple, effective systems that significantly reduce cooling energy use and improve indoor air quality. They increase the energy efficiency of the HVAC system to such a high degree that most energy codes require them on commercial applications. The International Energy Conservation Code requires economizers in any system larger than 54,000 Btuh, except for several extremely hot, humid, and cold climate zones.
Sometimes referred to as free cooling, an airside economizer system consists of a set of outside and return air dampers that operate together to reduce the load on the mechanical cooling system (compressors). When outside air conditions are cool and dry enough, the mechanical cooling can be shut off completely and the system can use outside air to cool the building, thus reducing the overall energy use of a facility. Indoor air quality is improved during airside economizer operation. That’s because a greater amount of ventilation air is provided to the occupied spaces than during the minimum outside air mode.