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Optimising the Fresh Air Economiser
This paper proposes using measurements of CO2 to infer the amount of Outside Air (OA) ventilation delivered to a space, either to diagnose over-ventilation, which can cause excess heating and cooling loads, or for Demand Controlled Ventilation (DCV), another method of ventilation control. The fresh air economiser is an energy saving strategy that modulates the amount of outside (fresh) air supplied to a space in order to reduce its cooling loads. This strategy can allow excessive amounts of ventilation during times when the economizer is not active, which can contribute to high heating energy use during peak conditions. The prevalence of building carbon dioxide (CO2) measurements in the 400 - 700 ppm range outside of the temperature range where economizers are intended to operate indicates that many buildings are supplying much (often ten times) more fresh air than is necessary.
Biship, R. (2013). Optimising the Fresh Air Economiser. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from