Jardinier, M.; Savin, J.L.; Berthin, S.
Bibliographic info:
29th AIVC Conference " Advanced building ventilation and environmental technology for addressing climate change issues", Kyoto, Japan, 14-16 October 2008

Maintaining a good indoor air quality (forpeople and building conservation) is obviously thefirst aim of any ventilation system; neverthelessthe main side effect - which is also the mostvisible one - is to spend energy, for heating firstand for transport.In these times of expensive energy, thetemptation is high to lower the ventilation flows,with few consideration on indoor air quality.Demand controlled ventilation is still oftenaccused of this behaviour and argued against asbeing "just a flow reduction". The philosophybehind demand controlled ventilation iscompletely opposed to this and come from theindoor air quality level to the energy conservationone: by no mean the purpose is to decrease flowswhen the demand is high, but to talze advantage ofthe fact that, in some periods, in some condition,the demand is lower and the flow can be adjustedwithout reverse effect on air quality. The swingbetween high flows and lower ones will lead toenergy benefit compared to a single continuousflow value, on a yearly and statistic base. Indwellings, humidity appears to be the bestcompromise between representative need,accuracy and cost. Measurement results are givento show the adequacy between humidity and needsin dwellings.The response of simple and cheap humiditycontrolled as the result of the swing between highand low levels is discussed and explained throughtheoretical examples, French regulation, andmonitoring results from Asia to Europe. Theincreasing potential for demand controlledventilation systems is presented through theevolution of the size of apartments andcorresponding occupancy in France as anexample. As a conclusion, humiditycontrolled ventilation - natural, assisted, ormechanical - has proved to be a reliable andrelatively cheap system, economically validin new or retrofit, in various climates.