ventilation system

Indoor environment quality has been researched extensively, with many countries adopting regulations to ensure that building occupants enjoy healthy working environments. In many small island developing states (SIDS), such as Mauritius, the population benefits from perfect weather conditions, but building design considerations often under-estimate the effects of outdoor weather conditions, heat and pollutant emission, illumination and noise, which worsen indoor environment.

Outdoor air is usually considered as a source of clean air in building ventilation principles. Although outdoor air quality has already improved in our cities, this principle may be challenged. Particulate matter remains especially problematic. This simulation study investigates the role that the mechanical ventilation system, with or without filtration, plays in the penetration of outdoor air pollutants, which may have adverse effects on indoor air quality and occupant health. Based on the Brussels PM2.5 pollutant data, several configurations were examined using the CONTAM software.

Purpose of the work

Is a ventilation system mandatory in airtight buildings? To what extent can users still be responsible for ventilation in modern buildings?

Method of approach

Evaluation of decision-making criteria for ventilation; normative specifications for the ventilation concept; energy efficiency potential of ventilation

Content of the contribution

Purpose of the work

This paper deals with the feedback of a full of a ventilation system reconditioning in a non- standard sealed building. This volume was previously retrofitted and immediately shows many difficulties to maintain good indoor air quality in some parts of the occupied volume. Indeed, a permanent well functioning of the ventilation system is essential in a sealed building without openings to ensure a good indoor air quality.

Method of approach

The present paper aims at illustrating the practical use of the Annex68 IAQ Dashboard. To this end, numerical simulations have been performed to provide useable data about the Indoor Air Quality (IAQ) of a low-energy detached house. The dashboard has been used to compare three possible solutions of ventilation systems commonly found in French residential buildings i.e. natural ventilation using vertical ducts for extraction, self-regulated exhaust and balanced mechanical ventilation.

This paper presents a comparative study based on CFD simulation between the performance of Impinging Jet Ventilation (IJV) and Mixing Ventilation (MV) systems in providing indoor air quality and thermal comfort for a mechanically ventilated occupied large open plan office (floor-to-ceiling height > 5m). Large spaces differ from spaces with standard heights because of the significant upward stratification.

Mechanical ventilation systems with heat recovery are considered the most optimal systems for residential ventilation. This research focuses on decentralized ventilation which do not need any ducting. Therefore, this system is very suitable for use in retrofitting. The performance criteria of these units are similar to those of central systems. A recuperative and two regenerative ventilation units were tested in a double climate chamber where temperature, air velocity and contaminant concentration were monitored on a fixed 80 point grid.

Airborne bacteria-carrying particles (BCPs) in an operating room (OR) can cause post-operative infections in the patients. The ventilation system in the OR is crucial in removing or diluting airborne BCPs. This study numerically assessed a newly developed OR ventilation scheme – temperature-controlled airflow (TAF), with special focus on the influence of heat loads on the airflow and BCPs concentration. TAF supplies clean air at different temperature levels to different zones and establishes a high-momentum downward airflow pattern over the operating table.

In a sealed building with tight facades, conditions for a good indoor air quality and comfortable conditions must be guaranteed all the time especially for employees. This paper deals with the case of a specific retrofitted building without any openings that immediately shows many difficulties to maintain good indoor air quality in some parts of the occupied volume. An assessment of ductwork and HVAC system performance was first realized, conducted by the SNIA (National Airport Engineering Service).

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.