Airbase publication

In the context of the PREVENT project, preparing a possible revision of the Belgian residential ventilation standard, the way of expressing ventilation requirements, among others in terms of ventilation flow rates, needs to be investigated. The aim of this paper is to propose and compare ways of expression of the ventilation requirements in terms of flow rates with respect to their robustness across dwellings.

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.

This study presents a comparison of three ventilation systems; automated Natural Ventilation (NV), balanced Mechanical Ventilation (MV) with heat recovery and Hybrid Ventilation (HV) with heat recovery for a new build office building.
The energy demand for heating and electricity as well as the indoor climate of the building were simulated using IESVE. Three key European cities were selected (Copenhagen, Munich and London) in order to investigate the applicability of the principles to different climatic conditions in Europe.

More than 64 million pupils spend more time in school than in any other place except home in Europe (European Commission, 2014). The indoor air quality is often a challenge in existing school buildings and the lack of proper ventilation often leads to negative effects like increased absenteeism and sick building syndrome symptoms as well as lowered performance amongst students compared to new buildings.

Urban warming, commonly referred to as the ‘Urban Heat Island’ phenomenon (UHI), is a well-established effect that affects cities all over the world. This occurs due to urban physical characteristics such as urban canyon geometry and vegetation, but mainly to its typical materials. The thermal properties of the materials used for the external walls and roofs of buildings, as well as pavements, can have a major influence on the surface temperature. As a consequence of increased temperature, the UHI has an effect on energy consumption for heating and cooling urban buildings.

Exposures to airborne fine particulate matter with a diameter of <2.5μm (PM2.5) are linked to multiple negative health effects, including cardiovascular and respiratory disease. Existing investigations of PM2.5 primarily focus on external sources and exposures, because outdoor air is easier to observe, and therefore, more widely monitored. However, as people spend up to 70% of their time in their own homes, exposures to indoor pollutants could have a greater impact on health. One method of investigating indoor exposures in a stock of houses is by modelling them.

CFD simulations were conducted to assess turbulent forced convection heat transfer and pressure drop through a ventilation channel using a stack of panels with different ridge configurations containing Phase Change Material (PCM). First, an experimental rig using an existing commercial panel provided by a PCM manufacturer validates the model simulated in Ansys FLUENT. After that, 3D simulations with different designs were tested until the optimum configuration in terms of heat transfer and pressure drop was achieved.

The aim was to study how the cooling jet from the ceiling, with individual control over the airflow, is perceived and how it affects the thermal comfort in warm office environment. 32 undergraduate university students participated in the experiment. Two thermal conditions were tested: (1) no cooling jet and (2) adjustable cooling jet from the ceiling. Subjects were able to use a controller with seven different settings to adjust the airflow coming from the nozzles so that the target velocity varied from 0.3 m/s to 1.5 m/s. The cooling jet was directed into the upper body.

For testing of general ventilation filters, a completely new standard is now available and is going to replace EN 779 (2012) since the parts 1 to 4 of ISO 16890 (2017) have been adopted in August 2016 and published in 2017 at both international and European levels. With this new standard, the fractional efficiency of the new and the conditioned (24 hours to isopropanol vapour) filters is measured between 0.3 and 10 μm.

Shopping centres currently design has included a small portion of automated windows sized for smoke ventilation. Their presence is mandatory for fire regulation and they are usually operated just in case of fire. Nevertheless, these buildings can potentially take advantage of those openable windows to exploit the potential of natural ventilation to guarantee the minimum air change rate required by IAQ standards and for ventilative cooling purpose reducing cooling and electrical consumption.