Performance of a demand controlled mechanical extract ventilation system for dwellings
Abstract
The main aim of ventilation is to guarantee a good indoor air quality, related to the energy consumed for heating and fan(s). Active or passive heat recovery systems seem to focus on the reduction of heating consumption at the expense of fan electricity consumption and maintenance. In this study, demandcontrolled mechanical extract ventilation systems of Renson (DCV1 and DCV2), based on natural supply in the habitable rooms and mechanical extraction in the wet rooms (or even the bedrooms), was analysed for one year by means of multi-zone Contam simulations on a reference detached house and compared with standard MEV and mechanical extract ventilation systems with heat recovery (MVHR). To this end, IAQ, total energy consumption, CO2 emissions and total cost of the systems are determined. The results show that DCV systems with increased supply air flow rates or direct mechanical extract from bedrooms can significantly improve IAQ, while reducing total energy consumption compared to MEV. Applying DCV reduces primary heating energy consumption and yearly fan electricity consumption at most by 65% to 50% compared to MEV. Total operational energy costs and CO2 emissions of DCV are similar when compared to MVHR. Total costs of DCV systems over 15 years are smaller when compared to MVHR due to lower investment and maintenance costs.
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