Demand Controlled Ventilation: Use in Calgary and Impact of Sensor Location

Abstract

Demand controlled ventilation (DCV) is used to reduce the amount of energy required to condition outdoor air introduced into a building based by monitoring occupancy. This thesis reports the hours DCV is used in an existing building in Calgary. Results showed DCV was used approximately 20% of annual fan operating hours when paired with an air-side economizer and just over 60% when a heat recovery wheel was part of the system. A Simulink model was built to compare the performance of two currently used DCV approaches based on carbon dioxide readings (CO2-DCV). The model showed positioning a sensor in the supply air duct (SACO2-DCV) to serve multiple zones of a re-circulating system maintained lower CO2 levels when occupancy varied between rooms than if the sensor were in the return-air duct (RACO2-DCV). The model showed these lower CO2 levels were due to SACO2-DCV over-ventilating spaces relative to typical requirements.