indoor air quality

Indoor carbon dioxide (CO2) concentrations have been used for decades to purportedly evaluate indoor air quality (IAQ) and ventilation. However, many applications of CO2 as a metric have reflected a lack of understanding of the connection between indoor CO2 levels, ventilation and IAQ. In many cases, an indoor concentration of 1800 mg/m3 (1000 ppmv) has been used as a metric of IAQ and ventilation without understanding its basis or significance.

Occupants control indoor environments to meet their individual needs for comfort. The control of window is the most common natural ventilation method influencing indoor environment as well as the energy use of the buildings to maintain a suitable environment. Therefore a better understanding of window control behaviour of the occupants has significant implication to enhance occupant comfort with minimal energy consumption. The objective of this study was to identify an appropriate algorithm and variables to develop a predictive model for window control.

The recent development of affordable and quite accurate temperature sensors and Indoor Air Quality (IAQ) sensors has led to a growing interest in continuous indoor climate monitoring. Not just amongst scientists and engineers but also amongst building owners, developers and e.g. architects interested in boosting our buildings’ health and comfort qualities.

By the end of 2020 all newly constructed buildings have to be nearly zero energy buildings (nZEB). In school and office buildings the ventilation system has a large contribution to the total energy use. A smart control strategy that adjusts the operation of the ventilation to the actual demand can significantly reduce this energy use. Consequently, control systems are becoming an important part of the ventilation system in these nZEB buildings.

In order to better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or IAQ advantage (or both) and less when it provides a disadvantage. This would be done in a manner that provides improved home energy and IAQ performance, relative to a “dumb” base case. This paper highlights that a favourable context exists in many countries, with regulations and standards proposing “performance-based approaches”.

As policy makers strive to reduce the energy demands of houses by reducing infiltration rates, an unintended consequence could be a fall in the quality of indoor air with corresponding negative health effects at a population scale. Measuring pollutant concentrations in-situ is difficult, expensive, invasive, and time consuming and so the simulation of indoor conditions, using representative models of a housing stock, is a more common method of investigation.

This presentation will summarize the last forty-five years of indoor air quality (IAQ) studies, investigations and research from the first energy crisis in the USA in the 1970’s to the latest issues with regards to climate change and its effect on IAQ. The initial occupant complaints about the quality of the air in buildings coincided with changes in infiltration and ventilation in buildings. In particular, the first ASHRAE 62 Standard was issued in 1973, and then substantially changed in the 1981 version.

The communication presents the Technical Appraisal Procedure followed in France for Demand-Controlled ventilation systems through the illustration of the use of a thermo-hygro-aeraulic nodal model called MATHIS developed by CSTB. The calculations methodology is described. Its application is illustrated for different family of ventilation systems currently under the scope of the procedure. The needs and the current developments for a better modelling of Indoor Air quality are lastly exposed. 

The implementation of the Energy Performance of Buildings Directive 2010/31/EU recast puts increasing pressure to achieve better building and ductwork airtightness.  

In this context, Eurovent Certita Certification decided to establish a new certification programme for Ventilation Ductwork Systems, opening a new chapter in the history of the Eurovent Certified Performance (ECP) certification mark, which concerned only products, not systems, until then.  

In order to better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or IAQ advantage (or both) and less when it provides a disadvantage. This would be done in a manner that provides improved home energy and IAQ performance, relative to a “dumb” base case. A favorable context exists in many countries to develop smart ventilation strategies.