What is ventilation and why is it important?

Warm air rising and cold air falling form air flow. As the air above the ground warms, it rises, creating an area of low pressure. As the air continues to rise, it cools and moves toward the surface, where it descends and forms an area of high pressure and pushes cold air toward land. This regional movement creates wind.

In architecture, ventilation is the introduction and distribution of outdoor air into a space. It comes in three different common forms: mechanical, natural and mixed ventilation. Managing outdoor air exchange and circulation is essential to creating a comfortable atmosphere. Whether by mechanical or natural means, a steady airflow can dehumidify and provide a permeable air flow that provides healthy air for breathing. A successful ventilation system must be consistent with the environment surrounding the project, whether it is the geographical location, the building materials, the building as a whole, or the habits of the users who occupy the space.

Recently, people have become more environmentally friendly and therefore choose more passive solutions to reduce energy consumption and carbon footprint. This awareness pushes aside automatic HVAC systems and replaces them with wind, a natural, free, renewable, healthy natural resource capable of adequately improving the air quality of Spaces. In Daniel A. Barber's "Modern Architecture and Climate: Design Before Air Conditioning," In Design beforeAir Conditioning, the author discusses how leading architects of the 20th century incorporated climate conditioning strategies into their designs, and how a regional approach to local conditions was crucial to the development of modern architecture.

Types of natural ventilation

Natural ventilation is an environmentally friendly system that does not require any automation or mechanical solutions. In addition to being more ecologically friendly, natural ventilation is also more economical, relying on external factors in nature such as wind and the temperature of the interior space and its surroundings.

Unidirectional ventilation

One-way ventilation is the use of openings on one side of the building for ventilation. This type of natural ventilation is often used for projects with limited area. Unidirectional ventilation systems are also used for projects that cannot provide crossventilation due to structural or environmental constraints. Note that when it comes to natural ventilation systems, this type of ventilation produces the least amount of air flow.

Convection ventilation

Convection ventilation is when openings in a building are set on opposite or adjacent walls, allowing air to enter from both sides, pass through the space, and leave in the opposite direction. The system is often used in buildings in warmer climates because it creates a continuous air circulation inside the building, reducing the internal temperature.

Stack ventilation

Chimney ventilation draws cold air from the outside into the lower levels of the building, which gradually warms as it is exposed to heat sources within the space. This causes warm air to rise and leave the space through openings located at higher levels. Generally, chimney ventilation is more effective in tall buildings with a central atrium, but it is also useful in buildings where convection ventilation does not fully penetrate the entire space. In order for a ventilation system to work properly, the indoor temperature must be higher than the outdoor temperature, which is why using it alone may not always be effective enough.

Chimney effect

In vertical buildings, the chimney effect is often used. Cold air creates pressure beneath the warm air, forcing it to rise. In this case, the open area of the building or tower allows the same air to circulate in the indoor environment, leaving through the roof, skylights, zenith openings, or vents.

Natural ventilation in different environments

Whether for environmental or economic reasons, some architects are unable to use automated ventilation systems as a solution in their projects and therefore have to rely on passive systems. To increase efficiency, natural ventilation relies on several factors. The shape, scale, orientation, location and materials of the building in a project can determine how much air enters and circulates within a space, as well as its efficiency. In theory, air must enter and exit through openings in the building, such as Windows, facade perforations, doors, solar chimneys, or wind towers. In terms of structure, projects with curved walls and partitions allow for more air circulation. Other influencing factors include the local climate, proximity to rivers, lakes or oceans, and pollution rates around the project.

The East Gate Center uses passive energy saving climate control solutions to cool residents. It's inspired by termite mounds. In accordance with Harare's climate, if buildings are required to be cool all year round, this means that the purchase, installation and maintenance of conventional air conditioning is essential. However, there are immediate and long-term costs to doing so. So the architects created a self-regulating ventilation system that keeps the building warm to meet the needs of workers and residents.

Originally known as the Universityof Ife, the university influenced by modernist Bauhaus culture was a product of politics, design and climate. Although Sharon wanted to rely entirely on modernism for this project, Nigeria's harsh climate forced the architects to look to local architecture for inspiration and come up with passive solutions for their designs. In fact, Sharon traveled to Mexico City to find architectural models for the building. The team of architects decided to design around the building's skin and facade by perforating the facade and adding grilles to create better shading and ventilation. "They inverted the pyramid, using the upper level to shade the lower level and freeing the lower level to open corridors, columns and patios. The view below the building is continuous. The clever location of the building allows air to flow freely, and it is a building without doors. At the same time, it also protects people from the rain through the balconies and eaves, and protects people from the harsh sunlight, ensuring continuous ventilation."

The Lee House consists of a single one-storey block with rooms opening out onto the garden. All the Windows in the living room are recessed and extend to the pool deck, across the other side of the open space, creating an extension of the outside space. In order to adapt to the almost year-round high climate of Sao Paulo State, the project blends traditional vernacular architecture with Brazilian modernist architecture. The living room adopts convection ventilation, which greatly reduces the indoor temperature. Other rooms are protected by wooden muxarabi(or musharrabiya) panels mounted on sliding doors that filter sunlight without affecting ventilation.

Built on the site of the former EDU headquarters in San Antonio Park, the project establishes guidelines and benchmarks for sustainable public architecture in Medellin that embrace "breathing architecture." A perforated outer skin composed of high-quality prefabricated components creates an internal solar chimney to circulate cold air from the outside. The materials used can generate thermal mass control and thermodynamic concepts - convexand thermal forces - to generate airflow in the workspace.

Increasing droughts, floods, and land salinization are jeopardizing food supplies. At the same time, the large number of motorcycles causes daily congestion and air pollution in the city. Rapid urbanization has deprived Vietnamese children of green Spaces and playgrounds, thereby depriving them of their connection to nature. The Agricultural Kindergarten is a project that takes on the challenge of these issues. The plant-covered roof is a three-ring shape that can be drawn with a single brush stroke, surrounding the three courtyard Spaces inside as a safe playground. The building consists of a continuous, long, narrow volume with switchable Windows on both sides to maximize convection ventilation and natural light. Building and mechanical energy saving methods are widely used, including but not limited to: green roofs as insulation, green facades for shading, the use of solar water heaters. Therefore, although the kindergarten is located in a tropical climate, the classrooms can still use no air conditioning. Text description provided by architect.

Vidana Restaurant is part of the Vidana Resort Master Plan, located in a forest on the edge of Cuc Phuong, at the foot of the mountains, with a rich diversity of vegetation species. The roof of the building is a three-story circular pitched roof with a span of 1,050 square meters, consisting of two stacked circular roofs and a dome roof at the top, each level of the roof separated by light strips. The restaurant is cleverly located next to an artificial lake that acts as a natural air conditioner. In Cuc Phuong Commune and northern Vietnam, summers are hot and humid, so the proper use of lakes is important.

The building is located in the countryside around Isfahan. The project sought to improve local construction techniques, use passive cooling ventilation systems, and train local contractors to carry out construction. The whole space can be extended to connect to the flower shelves, providing outdoor cooling space and protecting the facade from harsh direct sunlight. The building has a traditional Iranian Badger-Windcatcher, which provides enough height to hold the water tank. This is also a traditional passive ventilation method (shown in the figure). Traditional brick is the main material for the exterior and interior walls of the building, separated by a layer of insulation. Another feature of the building is the use of wind towers as a passive ventilation method in summer, which is also one of the traditional methods of Iranian architecture.

The tower's function is to ventilate the Northern Link traffic tunnel and reduce emissions levels at its entrance. The building is 20 meters high and takes the shape of a super triangle that rotates upward on its axis. The internal geometry and structure help to strengthen the exhaust flow; At the bend and top of the tower, the triangular section is wider, and the larger space reduces air resistance at the outlet. The role of the building is to divert contaminated air from the Northern Link traffic tunnel, thereby reducing the level of emissions at the tunnel entrance. An underground pipe connects each tunnel to the corresponding tower. The fans of the passageway are designed to generate a specific airflow through the ventilation tower, thus reducing the emission of the tunnel entrance to a sufficiently low level. The geometry and structure of the tower's interior affects the resistance of the air flow, which affects the flow of the air. The tower has been optimised to harmonise its function with the form of the building.