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Guests of this issue

Zhang Jie

Partner of EFC Engineering Consulting Co.,Ltd. 

"The main direction of transforming natural ventilation openings is to shorten the ventilation path, reduce ventilation resistance, and use air deflectors to solve the problem of ventilation short circuits. When there is an obvious dominant wind direction during the ventilation season, folded shapes can be used combined with components such as flying wings to capture More wind."

Characteristics of super high-rise ventilation openings

Safety and energy consumption issues coexist

1. Safety issues. High wind speeds at high altitudes increase the risk of hardware damage and opening windows falling off.

2. Energy consumption. Due to the obvious chimney effect of super high-rise buildings, the openings of super high-rise buildings lead to huge energy consumption in winter and summer, which limits the use of components such as ventilators that have good natural ventilation effects but average air tightness.

 

Protruding ventilation openings

Hongqiao Consortium Credit Center

The vents on both sides of the convex shape on the building surface often have different pressures. The pressure difference on both sides of the convex shape and the average pressure on both sides will have a greater impact on ventilation.

 

Design features of the vents of the project: convex decorative shape, horizontal grilles on both sides, and inward-opening and inverted windows on the indoor side.

The analysis shows that the average pressure difference on both sides of the hole is 10N/㎡. If the pressure difference on both sides is less than 5N/㎡, it has no impact on indoor ventilation. When the pressure difference on both sides is greater than 6N/㎡, short circuits begin to occur. When the pressure difference is greater than 19 N/㎡, The ventilation volume will drop to less than 1/3.

As mentioned earlier, when the pressure difference reaches a certain level, a ventilation short circuit will occur in the convex opening. Installing air guide plates in the convex cavity is more conducive to solving the problem of ventilation short circuits. Under the guidance of the wind deflector, natural wind is effectively introduced into the room.

When the pressure difference on both sides of the hole is kept at a fixed value, the greater the average pressure on both sides of the hole in the convex shape, the result is as shown in the figure, and the greater the ventilation volume.

The width of decorative lines also affects ventilation. Narrow size ventilation paths are shorter and the ventilation effect will be better.

Compared with the rectangular shape, when the convex shape is trapezoidal, the ventilation resistance is small and it is more conducive to direct wind into the room.

Recessed side ventilation openings

Qianhai Financial Centre

Ventilation design features: Qianhai Financial Center, concave shape, vertical grilles and inner casement windows on both sides.

As shown in the figure, the larger the width of the concave shape is, the greater the ventilation volume will be.

The greater the depth of the concave shape, the greater the ventilation volume. But the effect of depth is not as obvious as width.

When the fan is opened at an angle of 90 degrees, maximum ventilation cannot be guaranteed. The opening fan can be used as a wind deflector here. The ventilation efficiency can be improved by optimizing the angle of the opening fan. This project has the maximum ventilation volume when the opening angle is 67.5°.

Recessed front ventilation openings

New Development Bank

Design features of the vents: The New Development Bank has a concave shape, with vertical grilles and ceramic panels on the outside, and a sliding window on the inside front.

By comparison, it can be seen that the inclined entrance has the smallest ventilation path and ventilation resistance, which is beneficial to increasing ventilation efficiency. The entrance ventilation resistance at 90 degrees is greater.

When the ceramic panels in this project are moved internally and externally, they will have little impact on the ventilation volume. When the ceramic panels are moved outward, the ventilation volume of the hole on one side increases, while the ventilation volume of the hole on the other side decreases, and the overall impact is very small.

Shortening the ventilation path and reducing ventilation resistance is conducive to increasing ventilation efficiency. Dividing the opening window into two and arranging it on both sides is also conducive to reducing the ventilation path and ventilation resistance, thereby increasing the ventilation volume.

The following four types of inward-opening windows are inward-opening, inward-opening, inward-opening and inward-opening.

 

After analysis, it can be seen that the ventilation volume of the two types of inner casement windows is larger, especially in the opening direction consistent with the wind direction, the ventilation volume is the largest. Inward sliding windows and inward tilting windows will create greater resistance and less ventilation. Among them, the inverted window has the greatest resistance and the smallest ventilation volume.

Horizontal folded ventilation openings

New Generation Plaza South

Ventilation design features: New Times Square project adopts a horizontal folding shape, vertical grilles on the outside, and casement windows on the inside.

From the previous analysis, it can be seen that the advantage of the convex shape is that it can adapt to various wind directions. However, when the pressure difference on both sides of the convex shape reaches a certain level, a ventilation short circuit will occur.

 

The characteristic of the horizontal folded surface shape is that it will not cause ventilation short circuits, but it has strong direction, which is more suitable for cities where the dominant wind direction is very obvious in spring and autumn.

The larger the convex size of the horizontal folding surface also means that it can accept more wind and is more conducive to ventilation in the specific dominant wind direction.

Horizontal folding surface plus flying wing ventilation holes

China National Gold Building

Ventilation design features: CICC Tower adopts a horizontal folding surface shape, with flying wings on the outside of the folding surface. There is a vertical grille on the outside and an inner casement window on the inside.

The flying wings function as wind deflectors, helping to capture more fluid into the room.

Conclusion

Ventilation features of convex shape

1. The greater the width of the convex shape, the smaller the ventilation volume.

2. Compared with the rectangular shape, when the convex shape is trapezoidal, the direction of the ventilation opening is more conducive to direct wind into the room.

3. Installing an air guide plate in the convex cavity is more conducive to solving the problem of ventilation short circuit.

 

 

 

Ventilation features that open on both sides of the concave shape

1. The larger the width of the concave shape, the greater the ventilation volume.

2. Similar to the influence of width, the greater the depth of the concave shape, the greater the ventilation volume. But the effect of depth is not as obvious as width.

3. Ventilation efficiency can be improved by optimizing the angle of the opening fan.

 

Ventilation features of concave shape and front opening

1. Properly setting the grille angle can reduce the ventilation path and ventilation resistance, which is beneficial to increasing ventilation efficiency.

2. Reasonable placement of opening windows can also reduce ventilation paths and ventilation resistance, thereby increasing ventilation volume.

3. The ventilation volume of the inner casement window is larger, especially in the opening direction with the same wind direction, the ventilation volume is the largest. Inward sliding and inward-turning windows will create greater resistance, so the ventilation volume is smaller. Inverted windows have the greatest resistance and the least ventilation.

 

Horizontal folding shape ventilation features

1. Compared with the convex shape, the horizontal folding shape is characterized by the fact that ventilation short circuit will not occur, but it has strong direction, which is more suitable for cities where the dominant wind direction is very obvious in spring and autumn.

2. The larger the convex size of the horizontal folding surface is, it also means that it can accept more wind and is more conducive to ventilation in the specific dominant wind direction. The folded shape combined with components such as flying wings helps capture more wind.

 

According to the shape of the building and the characteristics of the environment, choosing the appropriate curtain wall, ventilation openings and opening forms can help improve ventilation efficiency, thereby providing a comfortable wind environment for the people living there.

Event Name: The 31st China Window Door Facade Expo

Event Dates: March 11 to 13, 2025

Event Venue: Poly World Trade Center, Guangzhou, China

Event Theme: One-Stop Solution for All Facade, Window and Door Needs

Event scale: 100,000㎡

Co-Located Event: Alpha Forum of Architecture