An economizer coil is a heat recovery device that uses cooler outdoor air or water to pre-condition building air or process fluid, reducing mechanical cooling demand during mild weather. These coils maximize free cooling opportunities while maintaining system performance and occupant comfort.
Operational Modes
Air-side economizer coils mix outdoor air with return air to lower entering conditions before mechanical cooling units. Water-side economizers use condenser water loops with outdoor coils to reduce compressor run time. Controls compare outdoor enthalpy or temperature to return conditions, activating economizer mode when energy savings exceed mechanical cooling costs. Properly tuned systems reduce cooling energy consumption 15-30% annually depending on climate zone and occupancy schedules.
Installation and Benefits
Economizer coils integrate with existing air handlers or standalone equipment with minimal ductwork modifications. Aluminum or copper tube construction withstands outdoor exposure and freeze cycles. Installation costs range $2,500-6,000 for typical commercial applications. Systems require damper controls, temperature sensors, and enthalpy controls to optimize operation. Service life extends 12-18 years with periodic coil cleaning and control calibration.