The shape of the architecture before the sun and the effect of the wind
Multiple agents intervene in a coherent and efficient architecture, although many times we forget - I believe - key points that economically are of practically "zero" cost and we focus more on having more efficient facilities or a more "spectacular" design.
There are other ways to shape architecture that will bring us benefits. Natural ventilation strategies thanks to prevailing winds affecting architecture that we can implement, in addition to taking advantage of the sun and its benefits.
The plot and the form of the building can be decisive to reduce or improve the heat gains from solar radiation and promote the direction of the winds in architecture. An example…
For this, it is necessary to consider different points of the environment, winds, sunlight, accesses, obstacles … etc. A compendium of elements, that well studied and executed from the beginning will cause future energy savings, although I think I remember that we will not be remembered in architecture for raising and executing these aspects properly.
Obviously it is not the same to build in the North of Spain as in the South, but the review points that we intend to show before starting the construction of a project can be adapted according to the climatic situation.
Natural ventilation and solar charges
In this case we focus on reducing solar charges (solar heat) and taking advantage of theNatural ventilation. Curiously, it also has an inverse game, the most points reviewed, the opposite would be to obtain higher solar charges.
Remembering the "inverse game" discussed above, we analyze points that we must consider in our architecture project.
Limit the assimilation of heat in the building, directing the narrower facades to the east and west
The solar heat gains They have their greatest impact on the surfaces perpendicular to the sun's rays, that is, on the roofs and the East and West walls throughout the year, and on the South wall in the boreal winter months (November, December, January). In buildings with the narrowest façades facing east and west, sun exposure is reduced at its lowest angle and better shading possibilities are obtained.
Solar gains chart
Locate the building on a plot
Locate the building on the plot in such a way that elements of the urban context are used to block or increase heat gains or maximize the cooling potential of the prevailing winds.
Elements of the urban environment such as topographic slopes, masses of vegetation or nearby buildings can cast shadows on the plots that can be used as sunscreen. (We remember the article of manuals in urban design with more than 30 relevant documents)
Here we must understand that the location of the Sun is very important with reference to the building. If we take it into account, they are all benefits and in the following scheme they are palpable (Orientation for Spain):
Use landscaping.
Use elements of landscaping to improve the microclimate of the plot and shade the building.
The location of elongated plants with the narrower facades oriented within an angle of 15º to 20 ° east-west, will reduce the heat gains in the mornings and in the afternoons when the sun acts at its lowest angles. Although the south facade receives high insolation during the boreal winter, this can be reduced with roof eaves.
Use the planters as volumetric elements to dampen the solar heat gains.
We can improve the microclimate of the plot with the help of masses of vegetation, hedges, planters and other elements. Shading walls and roofs with shrubs, lush trees, and pergolas can reduce solar heat gains through these enclosures.
All types of trees and shrubs that are close to the building must be selected in such a way that they produce adequate shade and at the same time allow air to pass through. Vegetation absorbs solar radiation and shades the ground, thereby helping to lower surface temperature. At the same time it cools the surrounding air through the perspiration of water vapor.
Use shading on exterior paved surfaces to lower the temperature.
With reference to sunny paved surfaces increase the temperature of the environment and affect visual comfort.
Air temperatures above sunny paved areas, such as parking lots, patios, and internal streets can be up to 7º C higher than on sunny unpaved surfaces, and up to 14º C higher than shaded unpaved areas.
Define paved outdoor areas to avoid reflection of surface heat from the immediate surroundings.
Dark colored materials such as asphalt absorb, conduct and re-radiate heat. Colored materials in construction sites such as glades such as concrete absorb, conduct and re-radiate significantly less heat but cause glare.
Use light elements with little paved surface as exterior traffic pavement, to reduce solar heat gains and glare.
Openwork pavers allow vegetation to grow in empty spaces. They are suitable for light traffic areas such as parking lots and garages. They are a good substitute for asphalt or concrete as they decrease the total area of these materials without eliminating the function as a rolling or parking surface.
Use play of volumes on the facades to create shadows.
Different planes that make up volumes, with projections and recesses, produce a set of their own shadows, thrown by the building, which reduces the assimilation of heat through the envelope and favors less hot interior environments. Of interest to see the article that offers free plans of ecological houses to download with 28 designs of large architecture offices)
Take advantage of the high thermal inertia of the soil as a design element.
At a certain depth, the soil temperature remains constant and is usually lower than the outside temperature. Additionally, a layer of soil can act as an additional insulator. The temperature damping that occurs depends on the depth and type of soil.
To dampen day-night variations, the thickness should be 20 - 30 cm, to dampen variations between days of different temperatures, a thickness of 80 to 200 cm, and to dampen winter-summer variations, thicknesses of 6 - 12 m.
Wind architecture
Provide wide spaces between buildings following the direction of the wind flow.
The seeing in architecture It should be considered as one more element when designing since it will provide us with advantages over natural ventilation that we must take into account. In the following diagrams, we can check the effects caused by the winds in the architecture on the building.
Faced with a distance between buildings of at least 5 times the height of the building upstream, it offers greater ventilation opportunities for the building downstream. We have to learn to use the wind in architecture to take advantage of its features.
Conveniently locate buildings to provide good ventilation around the urban structure. In the following diagram of winds over a group of houses we can verify its performance:
When we observe the air flow in a building creates a high pressure zone on the front face and a low pressure zone on the back face and on the faces parallel to the wind direction. The buildings aligned in the direction of the wind create wind shadows to the other buildings that are downstream and consequently poor ventilation.
This situation can be improved by orienting the buildings at a certain angle in relation to the prevailing wind direction. In this way, the effective distance between buildings is also increased.
Use masses of vegetation to guide air currents
Sometimes, the orientation of the building according to the solar path is in contradiction with that of the prevailing winds, but a studied arrangement of the exterior construction elements, volumetry and vegetation can change the direction of the moving air, providing different advantages. about the designed construction.
Use the volume of the building to stimulate air circulation inside the building.
For spaces with openings in opposite walls, orient the room 45% of the direction of the wind to improve airflow. Rooms oriented 45% from the prevailing wind direction increase their airflow by 20%.
On a façade with windows, oriented 45 ° in relation to the wind, placing a wall or projecting volume at the end can double the positive wind pressure. If, on the contrary, the wall or volume is placed before the windows, the pressure in front of them is reduced and the flow towards the interior is decreased.
Use the shapes and orientation of the roofs to stimulate air circulation within the buildings.
Taking into account the angle of inclination and the orientation of the waters of a roof, they can be used to deviate the original path of the wind, and in this way take better advantage of its dynamic force to ventilate the environments.
The inclination of the roof downwind will produce greater pressure on the incidence façade than flat roofs, as the wind path deviates upward and produces a greater negative pressure air mass downwind. The greater the slope, the better the effect.
Roofs with slopes opposite to the incidence of the winds produce a less negative pressure effect, because the air will tend more quickly to restore its original path to return to the ground surface.
Gabled roofs with orientation perpendicular to the incidence of winds in construction and with little slope they will allow the faster restoration of the leeward wind path, therefore the smaller the difference between overpressure and depression will be around the volume. With hipped roofs the effect is more evident.
Flat roofs with perimeter corridor eaves will decrease pressure fields around the volume. This situation can be improved by creating upward spikes to the perimeter of the eaves.
Separate the building from the ground to stimulate air circulation around and within the rooms.
When the wind rubs against the ground, it reduces air movement and makes it necessary to raise the building so that the speed of the air that passes through it is greater. This allows the envelope to give off heat by convection. Actually, there are many technical and constructive details that we must begin to understand, with the article on construction techniques for bioclimatic houses we provide detailed plans to download and be able to work.
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Obtained from:
- Field Guide for Energy Performance, Comfort, and Value in Hawaii Homes (Recommended Study)
- Bioclimatic design manual from HERE which includes a very interesting section on wind in construction (See from page 88)
- Natural ventilation efficiency and measurable
- Manual Sol y Viento with good explanatory examples of natural ventilation in buildings.
- Bioclimatic architecture
Indeed there are many factors that will determine the final shape of a building but we intend to show that the game between shape-wind-sun it can be a good base goal for any architectural project.
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