Demand control and constant flow ventilation compared in an exhaust ventilated bedroom in a cold-climate single-family house

ABSTRACT

A convertible, zoned ventilation system was field-tested in a modern, airtight Swedish home when occupied either by an experimental team or by a family. Indoor air quality in the master bedroom was monitored under four ventilation strategies. Relative to constant air volume strategies (CAV), demand-controlled ventilation (DCV) that was responding to CO₂ concentration extracted more air when people were present, but less in total over 24 h. This elevated the indoor air humidity, beneficial in climates with dry winter air. Multiple monitors within the bedroom indicated that vertical CO₂ stratification occurred routinely, presumably due to low mixing of supply air from a wall-mounted diffuse vent, spreading the air radially over the wall. This seemingly improved air quality in the breathing zone under local (ceiling) extract ventilation but worsened it during more typical, centralised extract ventilation, where air escapes the room via an inner doorway. The local extract arrangement thus seemed to yield both improved ventilation efficiency and reduced contaminant spread to other rooms. The noted air quality variations within the room highlight the importance of sensor placement in demand-control ventilated spaces, even in small rooms such as bedrooms.

KEYWORDS:

• Indoor environmental quality
• ventilation
• occupant comfort
• intelligent building
• digital homes

Acknowledgements

Dalarnas Villa is a collaboration between Dalarnas Försäkringsbolag and Högskolan Dalarna, with assistance from Luvian AB and Renson BV, and with financial support from Region Dalarna and the European Regional Development Fund, Norra Mellansverige, through the project Energiinnovation 2.0.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the European Regional Development Fund (administered by Tillväxtverket) and by Region Dalarna.

Notes on contributors

Ian Garman

Ian Garman is a PhD candidate with a background in energy efficiency and demand-side management.

Magnus Mattsson

Dr. Magnus Mattsson is a lecturer in building energy and indoor environments.

John Are Myhren

Dr. Jonn Are Myhren and Dr. Tomas Persson are associate professors in building construction and energy technology.