IAQ

In the Framework of the IEA EBC Annex68 Subtask 1 working subject, we aimed at defining an indoor air quality index for residential buildings based on long- and short-term exposure limit values. This paper compares 8 indoor air quality indices (IEI, LHVP, CLIM2000, BILGA, GAPI, IEI Taiwan, QUAD-BBC and DALY) by using the French IAQ Observatory database that includes pollutant concentration measurements performed in 567 dwellings between 2003 and 2005. This comparison allows to make a relevant analysis of each index and determines their pros and cons i.e.

Demand controlled ventilation (DCV) can improve the energy performance of all kinds of ventilation systems, in residential and non-residential buildings and is already part of the European Lot 6 and Ecodesign regulations and standards. However, the lack of recognition of DCV in SAP (Standard Assessment Procedure) forms a great barrier for the use of this technology in the UK. A methodology was developed to prove the guarantee on good IAQ, with potential saving on heating and auxiliary energy by modulating ventilation rates based on actual demand.

Ventilation systems play an important role in providing a good indoor air quality in dwellings. Mechanical exhaust ventilation systems implement natural vents to supply outdoor air to the dwelling. Natural driving forces, i.e. wind and thermal draught, influence the flow rates through these supply vents. Therefore, the flow rates depend on the weather conditions and vary in time. This study considers the influence of the wind and thermal draught on the operation of a mechanical exhaust ventilation system in a reference dwelling.

Demand controlled ventilation (DCV) refers to a ventilation system with air flow rates that are controlled based on a measurement of an indoor air quality (IAQ) and/or thermal comfort parameter. DCV operates at reduced air flow rates during a large amount of the operation time. Due to this decrease, less energy is needed for fan operation and heating/cooling the supply air. However, uncertainty still exists about the IAQ performance and ventilation efficiency in the room, especially at lower air flow rates.

Controlling indoor humidity is important in homes, because high indoor humidity is associated with occupant health and building durability issues. Ventilation is often used to avoid peaks of moisture in homes, such as in kitchens and bathrooms. However, in hot-humid climates, outdoor air can have higher humidity than indoors, and continuous whole house ventilation can lead to increases in indoor humidity levels.

Recently research at the Eduardo Torroja Institute for construction sciences proposes a new wording for the IAQ regulations for dwellings included in the Spanish Building Code.
The main goal of the earlier research was to adapt required ventilation rates to real needs to achieve a reduction of ventilation rates and energy demand with no negative impact on indoor air quality.