natural ventilation

In this study, we propose a method for forecasting heat emission effect in a small single-sided slit opening. In order to make a heat flux forecasting model, we carried out field measurement, wind tunnel experiment, and CFD analysis. In the field measurement, we measured heat flux and grasped the relationship of heat flux of the opening and airflow around the building surface. In the wind tunnel experiment, we measured airflow around the opening and grasped turbulence characteristics.

Passive stack ventilation is a key feature of sustainable building design and has particular potential for use in tall, multi-storey buildings. However, natural ventilation flows through multiply connected spaces may not behave as expected. Recirculation of air through occupied parts of the building and bidirectional exchange flows at ventilation outlets may compromise the intended ventilation scheme resulting in an uncomfortable indoor environment.

Wind catchers are natural ventilation systems attached to buildings in order to ventilate the indoor air. In order to design and evaluate the performance of wind catchers, as a natural ventilation system, an accurate CFD simulation of indoor airflow and outdoor wind flow is fundamental. It is widely known that there are a large number of computational parameters influencing CFD simulations. Consequently, comprehensive sensitivity analyses of the effect of these parameters on the simulation results are essential to provide guidance for the evaluation of a CFD study.

The aim of this paper is to illustrate the impact of urban wind environments when assessing the availability of natural ventilation. A numerical study of urban airflow for a complex of five building blocks located at the University of Reading, UK is presented. The computational fluid dynamics software package ANSYS was used to simulate six typical cases of urban wind environments and to assess the potential for natural ventilation. The study highlights the impact of three typical architectural forms (street canyons, semi-enclosures and courtyards) on the local wind environment.

The prevailing paradigm in indoor environment control of office buildings often excludes natural ventilation, due to the fact that its dynamic nature may not be compatible with the close control of mechanical conditioning systems. Due to the potential magnitudes of wind and buoyancy forces in tall buildings, the challenges are greater. This research is concerned with the prospect of purely naturally ventilated tall office buildings. The naturally available driving forces of wind and buoyancy are investigated separately or in combination.

The built environment in China is required to achieve a 50% reduction in carbon emissions by 2020 against the 1980 design standard. A particular challenge is how to maintain acceptable comfort conditions through the hot humid summers and cold desiccating winters of its continental climate regions. Fully air-conditioned sealed envelopes, often fully glazed, are becoming increasingly common in these regions.

Based on the theoretical and experimental studies of natural ventilation, the performance of natural ventilators has been analysed. Four types of natural window ventilators and three types of wall ventilators were studied. Experimental results show that the natural ventilators have a greater ventilation effect whilst meeting national and local standards of ventilation for residential buildings in heating or cooling seasons.  The installation of such devices can be a compromise between ventilation and energy loss.

In a world where energy conservation in buildings is an important target, natural ventilation is an important field in which carbon footprint reductions can be achieved. This paper investigates the possibility of creating horizontal channels to deliver natural cross ventilation passively in deep-plan buildings that otherwise would suffer from a lack of fresh air ventilation. The research objective has been to find a new system in which the depth of buildings is no longer an issue when it comes to natural ventilation.

Natural ventilation in residential dwellings is very important for occupants’ health and comfort. Previous studies by the authors have concluded that natural ventilation performance in dwellings can be enhanced by positioning the two groups of window openings (bedroom windows and living room windows) in opposite directions or perpendicular to each other; and/or the use of side-hung windows. However, the buildings selected for those studies were located in an isolated site, for the purpose of focused evaluation of the influence of various configuration parameters and window types.

It is still difficult to confirm from available data if global warming and climate changes have played a role in increasing heat-related injuries. However, it is certain that global warming can increase the frequency and intensity of heat waves, which can cause discomfort to the human body and, in the worst case, can lead to more heat illness casualties. Recent worldwide natural disasters, such as the Tohoku earthquake in Japan, flooding in Thailand, and the Pakistan heat wave show that climate change is truly a fact.