There are two AAON ERV units that condition the air in the North Wing. ERV units exchange energy in the exhausted air and use it to pretreat the incoming outside air using a desiccant well. This improves the indoor air quality, and at the same time the equipment capacity can be reduced, which decreases the electrical energy needed to heat and cool the space.
Demand control ventilation is a technique that allows the spaces to meet the fresh air requirements of the school when needed by occupant demand. Located in every group meeting space is a CO2 sensor that is used to determine the ventilation need. As the ventilation need increases, the amount of outside air is increased by speeding up the fan. As ventilation need decreases, the amount of outside air is decreased by decreasing the speed of the fan.
The ability to increase or decrease fan speeds is due to variable frequency drives. Variable frequency tires (VFDs) can reduce noise, reduce wear, and reduce electrical charges by only delivering the amount of power necessary. In fact, all of the pumps, supply fans, exhaust fans, and energy recovery wheels are equipped to run at variable speed to maximize comfort and efficiency.