Demand controlled residential ventilation: field tests

The performance of four approaches to demand controlled residential exhaust ventilation systems that are commercially available on the market were monitored in real life implementations. Their performance was assessed both on the level of heat loss through ventilation and on the level of indoor environmental quality. For the heat loss performance, the fan power was continuously measured to know the exhaust flow. For the indoor environmental quality, the carbon dioxide concentration, the temperature and the humidity level in each of the rooms in the houses were monitored. The systems and the houses they were integrated in were modeled in multi zone simulation software and the predicted performance was compared to the monitoring results. Information on the interactions of the occupants with the system was gathered by questionnaires about the occupants’ habits. The results also demonstrate that the performance of the monitored systems, as far as ventilation heat loss is considered relatively to that of a constant air volume exhaust system, is severely limited by adventitious ventilation and infiltration and is largely dependent on the occupancy and other specifics of the particular case. This indicates that the systems react appropriately to changes in pollution source strength, achieving a better exposure to heat loss trade off than constant volume flow systems