English

The utilization of natural ventilation helps to reduce building energy consumption and improve indoor air quality. In the urban area, the performance of the natural ventilation is very sensitive to surrounding building density. However, the influence of surrounding buildings on ventilation rate was not well investigated in previous research. This paper presents a wind tunnel experiment to assess the influence of urban density on the wind-induced ventilation rate of single-sided ventilation.

Air-supplied ceiling radiant air conditioning is expected to become more popular in Japan in the future because there is no leakage from pipes and no condensation on the surfaces of radiant panels. Coanda air conditioning, a type of air-supplied ceiling radiant air conditioning, uses the Coanda effect, which is the tendency a fluid passing near a wall to maintain contact with it. As used commonly, Coanda air conditioning cools the ceiling surface by blowing airflow horizontally along it from the top of the wall surface and cooling by radiation1).

Computational predictions of buildings' indoor-environmental conditions and energy performance would presumably benefit from the inclusion of models that could reliably capture occupants' window operation behaviour. Frequently, models derived from empirical data have a black-box character. However, the utility of window operation models could be conceivably improved, if the model derivation process is preceded by specific hypotheses regarding the variables that are assumed to influence the frequency and timing of window operation actions.

One proposed mitigation to reduce transmission of the SARS-CoV-2 virus and other airborne pathogens is to increase ventilation in buildings. This measure can be difficult to implement in existing buildings and has the potential environmental costs of increased energy consumption to condition the additional airflow, as well as other potential costs such as the disposal of existing serviceable mechanical equipment and the manufacture and delivery of new equipment.

Monitoring and regulating the air quality inside critical infrastructure is essential for protecting occupants from external and internal airborne threats, such as pollutants, toxic chemicals, and pathogens. The outdoor air can be contaminated with agents such as diesel and car exhaust or with more toxic agents like Toxic Industrial Chemicals (TICs). In case of a pandemic, there is a threat of viruses and bacteria which can spread in the building. These airborne agents can penetrate and disperse inside the building via windows and doors or via the ventilation system.

Most current building materials are industrially processed, resulting in increased carbon emissions. Global annual carbon emissions due to construction materials reached its peak in 2013, 9.5 gigatons of CO2 were produced. Upcoming circular economies can have a positive impact on the environment since reusing materials can lower carbon emissions. This economy encourages the use of more innovative materials (e.g., textile insulation, cellulose insulation, hemp, and cork) and recycling old materials.

The quality of indoor air in buildings depends on many factors. Some of these factors have internal sources, and some have external sources. The internal loads of the room include those generated by people: CO2 and moisture emissions from breathing, heat emissions from room equipment: volitale organic compaunds VOC. External sources are, for example, particulate matter present in the air, which is the result of emissions from cars and the burning of fossil fuels. The scientific literature states that car traffic can contribute a large share.

Nowadays, people spend most of their time indoors. Homes, offices, leisure and workplaces must meet people’s needs and provide safe, healthy and productive environments. The supply of fresh air plays an important role in achieving these goals. Not only by providing the right temperature and humidity but even more with the purity of the air inside the rooms. A recent study of the World Health Organization showed a significant correlation between yesterday’s particulate matters concentration in outdoor air and today’s death rate counting 7 million deaths in 2022 caused by air pollution.

Open offices, where more than one person works, have been used frequently in recent years. However, there are many studies on the efficiency of the indoor air quality of the employees in these offices. It has also been shown that the risk of cross-contamination is higher in such offices during the COVID period, but this risk can be reduced by increasing the amount of fresh air.

The main task of every ventilation system is to dilute and extract pollutants from indoor air, most importantly in occupied space. This is usually achieved by exchanging polluted indoor air with less polluted outdoor air. In the case of a mechanical ventilation system, this process requires a fan power to be provided which is approximately proportional to the power of three to the resulting airflow. Because of this, reducing the necessary airflow to be provided by the ventilation unit e.g., by 10% would lead to a reduced power supply of about 27%.