Jean-Luc Savin, Stéphane Berthin, Marc Jardinier
Bibliographic info:
35th AIVC Conference " Ventilation and airtightness in transforming the building stock to high performance", Poznań, Poland, 24-25 September 2014

Is Demand-controlled ventilation a relevant answer to face the new challenges of the Building sector, which requires everyday higher energy efficiency and better indoor air quality? Can Demand-controlled ventilation be considered as an alternative to heat recovery ventilation, through an affordable and low maintenance solution? Since the take off of the DCV in the early 80’s, these questions have been considered many times. Following the expansion of the technology over the world (more than 4.5 million dwellings are already equipped today, only considering humidity controlled ventilation), numerous in-situ monitoring have been conducted to try to better understand the behaviour and the performance of the DCV. Precursor in the field as inventor of humidity controlled ventilation in 1983, Aereco has carried out numbers of monitoring on different ventilation types, in various countries and on specific buildings, measuring in total hundreds of dwellings. With a first large-scale study based on natural ventilation in multi-storey buildings realised in 1993, the research has been completed with experiments on hybrid ventilation and on mechanical exhaust ventilation, individually or collectively managed, to recently lead to the follow-up of on an innovative full room-by-room DCV balanced system with heat recovery.

This proceeding will specially focus on four major monitoring: demonstration project “EE/166/87” (natural ventilation, France, Belgium and Netherlands, 1991-1993),  “HR-VENT” (hybrid ventilation, 55 dwellings, France, 2004-2005), “Performance” (collective MEV, 29 dwellings, France, 2008-2009) and the last monitoring that concerns several houses in Germany and France equipped with a full DCV heat recovery (started in 2013).

In parallel to the ventilation systems evolution, the one of the measurements methods and instruments has been remarkable since the first monitoring. From tracer gas to collect the airflows at the first monitoring, we have reached today a level of technology that enables more reliable and more precise multi-parameters measurements through electronic sensors, sending data via internet.

Whatever the ventilation technique it is associated with, the automatic control of the airflows according to the demand has demonstrated benefits at various levels. The first monitoring highlighted the correlation between CO2 and humidity, even in the technical rooms, conferring relevancy to humidity controlled at the exhaust. On all monitoring, the seasonal behaviour of the system when humidity controlled has been found out: following the lower absolute humidity level in winter, the airflows are reduced when the dwellings are unoccupied, leading to energy savings on both the heating and on the fan electrical consumption. On the indoor air quality side, we have checked that the automatic control to the demand enables to optimise it: the system improves the repartition of the airflows among the rooms according to their specific needs, increasing the air renewal in the most occupied and polluted rooms. In addition, DCV monitoring have shown specific phenomena such as the ability to optimise the available pressure through a time-repartition of the exhaust demand dwelling-to-dwelling, when connected to a collective duct. Besides parameters measurements and data collection we brought specific care on occupant’s acceptance, making surveys every time it was possible. The results have shown that the system was in general very well accepted, highlighting the relevancy of non intrusive and low maintenance systems.