The use of wind and thermal buoyancy to create air movement in and out of your home without the use of mechanical systems to deliver fresh air into your home is known as natural ventilation. During the summer months, natural ventilation can provide free cooling while also lowering your home’s energy consumption. Natural ventilation is usually considered during the planning stage of a house. To remove stale air and replace it with fresh air, ventilation is necessary for buildings.
Given below is the list of advantages of natural ventilation:
- Assisting in the regulation of interior temperatures.
- Assisting in the control of humidity.
- Oxygen replenishment.
- Moisture, smells, bacteria, dust, carbon dioxide, smoking, and other impurities accumulated during occupied periods are reduced.
- Creating air circulation that promotes occupant comfort.
Natural ventilation is often the first option explored throughout the design phase since it is less expensive to create, run, and maintain than mechanical ventilation. However, there are several situations in which natural ventilation is not practicable, and mechanical ventilation is required:
- The structure is too large to ventilate from the outside.
- If a building is located near a busy road, for example, the local air quality is bad.
- Because of the high levels of noise in the area, windows cannot be opened.
- The dense urban structure in the area protects the structure from the wind.
- Windows cannot be opened because of air cooling or air conditioning equipment.
- Windows cannot be opened due to privacy or security concerns.
- Internal partitions obstruct airflow.
Some of these problems can be avoided or lessened by carefully planning the building’s location, orientation, siting, zoning, and design.
Natural ventilation is classified as follows:
1. Wind-driven ventilation
When the wind blows over a building, it makes contact with the windward wall, causing a positive pressure to develop. Simultaneously, a negative pressure occurs on the opposing wall, commonly known as the leeward wall. Fresh air will enter through the openings on the windward wall and depart through the openings on the leeward wall if there are any on the home’s windward and leeward walls. More air can move through the building with stronger wind and larger openings.
2. Stack ventilation
The primary cause of thermal ventilation, also known as buoyancy or thermal ventilation, is temperature changes within a dwelling. As the temperature in residence rises, the air density decreases, causing the air to rise. This warm air will exit through a window or entrance higher up in the house, allowing cool fresh air to enter through lower openings.
Cross-ventilation and the chimney effect are two examples of natural ventilation methods. Other elements, such as the sun’s orientation, technical possibilities, the location of the openings, and many others, all play a role in determining the best approach and how to implement it. When it comes to interior design, however, the goal is to aid or promote natural ventilation by the existing built environment.
Using screen blocks on the facades to allow not just ventilation but also natural sunlight and some degree of visual permeability is one of the first alternatives which can be preferred. The upper floor of Jacobsen Arquitetura’s idea for the GAF House is completely encased in a wooden skin composed of moveable and fixed panels arranged in metallic frames. Several prototypes and specific opening systems were necessary for the creation of this part. The wood panels are employed as room dividers in the office on the mezzanine, transmitting a unique identity for the overall project in addition to providing visual protection and allowing in natural light and ventilation.
Following are some of the examples of various remedies for natural ventilation adopted in the respective projects:
1. Apartment 112 Sul by CoDA Arquitectos
CoDA architects decided to demolish select walls while emphasising the existing screen block facade in their refurbishment of Apartment 112 Sul. The significant reduction in the laundry area was the essential element that enabled the kitchen and living room to be connected, thereby opening the view to the back facade and introducing a new protagonist to the space: the cobogó wall.
2. VY ANH House by Khuon Studio
Khuon Studio’s alternate design for the VY ANH House has a louvre system that entirely covers the exterior as well as air bricks placed in random patterns to provide security, ventilation, and aesthetic emphasis. This structure also serves as a trellis that will be gradually covered with vines, creating a greenery curtain that gives shade, seclusion, and comfort through cross-ventilation, while also generating unique places inside the house.
3. Floating Nest House by Atelier NgNg
The Atelier NgNg’s Floating Nest House takes the link between the facade and the inside to a new level. The difficulty for this home was to integrate a large programme onto a small and constrained plot of land while simultaneously coping with the local environmental variables. Within the house, the architects decided to forego partition walls in favour of using vegetation and voids to divide functional zones. The bamboo screen that runs the length of the facade provides for natural airflow while also shielding the entire house from the harsh West sun and providing a great level of privacy.
4. Hayden Place by Cuningham Group
Natural ventilation in offices and workplaces is notoriously difficult to achieve. The Cuningham Group’s Hayden Place, aiming for LEED Gold certification, has several environmentally-friendly features, including trickle vents that allow fresh air to circulate throughout the space and exit through mechanical ventilation via exhaust vents on the opposite end of the building. These ducts blend in with the rest of the design without becoming distracting.
5. Double skin façades
In some regions, the climate is very hot and therefore, the use of glass becomes difficult. And hence, the provision of curtain walls for commercial buildings become tedious since the internal spaces get warmer during the summers. In order to tackle this problem and achieve natural ventilation, a double skin façade can be provided. This is done by providing two skin façades thereby, leaving a cavity of 1.5 meters maximum.
The outer skin may be without openings. However, the inner skin should have window openings to procure natural light. The external glazing absorbs the heat but does not affect the inner skin due to the presence of the cavity in between. The windows can be opened whenever needed.
To enhance this system, the outer skin shall at least be 0.6m clear from the ground level to allow airflow. Due to this, the stack effect will be created, allowing the warm air to rise up and exit from the top, leaving the cool air to enter through the openings.
Therefore, there could be many problems that will differ according to location, materials, climate, etc. These challenges can be tackled with appropriate solutions to achieve natural ventilation. In some cases, interior designers may have to compromise with the cost. Nevertheless, natural ventilation being a primary need, should be given preference in all cases.