ventilation

In 2017 the Danish Building and Property Agency started a project titled “Avoiding energy waste in ventilation systems” by tracking the actual energy use in a sample of their 4 million m2 portfolio of buildings through on-line energy management tools. The project is not complete, but the key preliminary findings  described in this paper are: 

Between 2017 and 2018, the Centre for Studies and Expertise on Risks, the Environment, Mobility and Planning (Cerema) organized an airtightness measurement campaign in 117 multi-family collective and single-family French dwellings. These dwellings were built before 2005, that is, before the release in 2005 of the fifth French thermal regulation for new dwellings, that was the first to introduce specific requirements for airtightness.

Ventilation is critical in interpreting indoor air quality (IAQ), yet few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully described. Most ventilation assessments use a tracer gas test (TGT) to measure total air change rate. In a TGT, the indoor air is marked with an easily identifiable gas (tracer) so that the air change rate can be inferred by monitoring the tracer’s injection rate and concentration.

Measuring ventilation rates in occupied dwellings is challenging but represents the conditions that occupants experience. This paper explores the constraints of existing methods when measuring the ventilation rate of occupied buildings and proposes a new method addressing some of them.  

Infiltration is an uncontrolled contribution to ventilation in a building and can contribute significantly to the total ventilation rate, particularly in older, leaky, dwellings which can rely on infiltration to provide adequate indoor air quality. However, as explored in this paper, using a whole house airtightness metric to characterise ventilation rates can fail to identify low ventilation rates in specific rooms. 

The indoor thermal comfort and air quality in classrooms have become of interest worldwide, predominantly because of their influence on children’s health, learning performance and productivity. Growing concerns with building energy efficiency emphasize the significance of this topic. This paper illustrates the outcome of a field study conducted in secondary school classrooms in Sydney, Australia, during the school year in 2018/2019.

The indoor air quality is very important for the well-being of occupants, especially in the case of young babies. This research focuses on the air quality of the surrounding air inside a crib with sleeping infants. To study the effects of different sleeping positions of the baby with in the crib a measurement setup was created in the laboratory. The breathing of an infant was simulated by means of a baby doll with air supply mixed with CO2 and measured at different sensor locations for different sleeping positions.

Within the ventilation principle of buildings, the outdoor air is considered as a source of fresh, "clean" air. Outdoor air quality monitoring by environmental agencies, academic research projects and a broad range of citizen science projects show that this is not always the case. Although the outdoor air quality in our cities already improved, the concentrations of certain pollutants, especially particulate matter and peak pollutions of ozone (and its precursors nitrogen oxides and volatile organic compounds), remain problematic.

Combustion appliances are used in many buildings to provide space heating and domestic hot water. These appliances emit smoke that contains pollutants that must be kept away from the ventilation air supply of the building, to limit their impact on the indoor air quality (IAQ). An efficient way to prevent those pollutants from entering the ventilation circuit is to place the chimney terminal above the top of the roof, as far as possible from the air supply openings.

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