Demand Controlled Ventilation (DCV) and Energy Savings : application on sites

DCV is one of the main issues in the near future due to the large potential of energy savings,the importance of maintaining a good IAQ with an adequate ventilation rate and the optimisation of system sizing. Nevertheless the technology or sensor used must adequately follow the actual demand. The study shows on site results on two different technologies.The first site is a collective dwelling installed with natural ventilation system situated in Nangis, near Paris (France) which has been renovated with hybrid ventilation and humidity controlled outlets and inlets. HR-VENT is an in-situ monitoring which exceptional character lies in the dimension as well as in the used measurement means. With more than 700 million data saved during two years out of 55 occupied dwellings, the experimentation made it possible to measure the effectiveness of a new ventilation system and contributed to enrich the knowledge on the operation of natural and hybrid ventilation in collective dwellings. From January 2004 to December 2005, the data of relative humidity, temperature, pressure and extracted airflow were saved every minute in each technical room, using specifically developed sensors. Directly related to the meteorological data, these measurements allowed to evaluate the performances of the humidity sensitive ventilation and the contribution of the mechanical assistance; they also determined the capacity of the hybrid system to improve indoor air quality and to control the thermal losses. The second site is a meeting room of an office building which has been installed with a mechanical DCV system using optical (infra-red) sensors to determine the number of occupants. The results on site show the performance of the system and adequate determination of the real number of occupants, assessed by webcam, and the induced results in IAQ and energy. Although DCV is common in residential ventilation, it is not yet frequently used in non residential area. We expect an increase of DCV systems in the future to fulfil the targets of energy regulations. The potential of savings is tremendous on the market and products and solution are more and more common