Achieving Net Zero

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Designing a net zero building was at first thought to be something to strive for…but something that was not realistic. A net zero building is one with zero net energy consumption and zero carbon emissions annually.

Designing a building that operates with no net energy usage is difficult at best, but trying to do it on the budget of a public school system is next to impossible. This is what CMTA Engineering set out to do when they started to design Richardsville Elementary School in 2008. At the time, such a school did not exist in the United States.

Instead of relying on upgrades and changes to existing school designs, the Engineers had to start from scratch – rethinking literally everything. To meet the goal, the project demanded innovative strategies when it came to the HVAC design. The HVAC load in a typical building consumes 40-50% of the energy usage.

Air Equipment Company was honored to be involved in the design of this innovative HVAC system. Though the use of an Aircuity Demand Control Ventilation system, a dedicated outdoor air unit only provides the minimum required fresh air to the spaces – based on occupancy levels. The Aircuity system centrally tests the air quality in each space. A pneumatic air system returns air from each occupied space to have it “tested” at a common location. The air quality testing system communicates with the Building Automation System. As CO2 levels increase in the space, the VAV box increases airflow to the space and reduces airflow as the CO2 levels decrease. When no occupancy is sensed, the classroom is placed in the unoccupied mode. This system alone accounts for over 8000 kWh of energy savings annually.

The Fall 2012 issue of High Performance Buildings Magazine did a feature Case Study on Richardsville Elementary. You can check it out here.

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