The HVAC system at Jessie Thackrey Preschool was installed in 2014 and is one of our newer systems that has a computer-controlled economizer that adjusts airflow based on outside conditions. The economizer uses a system of sensors and dampers to adjust the amount of outside air brought in, the amount of recirculated air, and the amount exhausted from the building. The purpose is to increase the operational efficiency of the system by reducing energy consumption by reducing the amount of cooling/heating needed. The average position for the units was increased to 20%, but the system can go up to 30% if needed. It will never fall below 12% which is the minimum setpoint.

The HVAC system at Mt. Daniel has 3 separate systems installed in 2005, 2016, and 2018 respectively. The 2005 system is much like the system at MEHMS and has manually adjustable dampers. Currently, the dampers in that space are set to 20% outside air. The 2016 and 2018 systems, being newer systems, have a computer-controlled economizer that adjusts airflow based on outside conditions. The economizer uses sensors and dampers to adjust the amount of outside air brought in, the amount of recirculated air, and the amount exhausted from the building. The purpose is to increase the operational efficiency of the system by reducing energy consumption by reducing the amount of cooling/heating needed. The units' average position ranges around 20%, but the system can go up to as much as 50-60% if required by the economizer sensors. It will never fall below 12% as that is what we have the minimum setpoint set to. 

The HVAC system at Oak Street Elementary was installed in 2016 and is one of our newer systems with a computer-controlled economizer that adjusts airflow based on outside conditions. The economizer uses sensors and dampers to adjust the amount of outside air brought in, the amount of recirculated air, and the amount exhausted from the building. The purpose is to increase the operational efficiency of the system by reducing energy consumption by reducing the amount of cooling/heating needed. The units' average position ranges around 20%, but the system can go up to 30% if needed. It will never fall below 12% as that is what we have the minimHeadlineum setpoint set to. 

The HVAC system in MEHMS was installed in 2004. While it is newer, the system requires manually adjusting the dampers in the RTU's. We increased the airflow to 20% outside air as compared to the 10% required by code. 

The HVAC system in FCCPS new high school is a once-through air system and does not recirculate ventilation air from any individual spaces to any adjacent spaces. Conditioned (room neutral) outside air is ducted from floor by floor units to each fan coil unit, providing ventilation to the building occupants. The system utilizes a demand control ventilation sequence to modulate variable air volume (VAV) dampers at each FCU, controlling the amount of outside air delivered to each space based on CO2 levels. This approach means that all ventilation air in the building does not transfer between classrooms, floors, or other occupancies. Each DOAS unit filters the outdoor air providing additional protection through filtration for contaminants in the air stream. The major assembly spaces in the building (Cafeteria, Theaters, and Gymnasiums) are each served by their own dedicated air handling unit. Each unit provided both ventilation and heating and cooling within a combined air stream. For these spaces, it does mean that the air is recirculated within the assembly space. In the Meridian cafeteria, auditorium, and gyms, needlepoint bipolar ionization was installed to add an extra level of protection in assembly spaces.  These UL 2998-certified systems meet the ASHRAE qualification standard for zero ozone omissions.