Before developing technologies and materials, people used the resources offered by nature to protect themselves from cold and heat. Trees, mountains, rivers, winds and sunshine, to mention a few, were the elements that determined the air conditioning of their homes. Many forgot this knowledge when technology began to offer solutions, which can be very practical, but usually use many resources and/or pollute the environment.
Bioclimatic architecture rescues some of our ancestors’ knowledge by considering the environment conditions to design buildings that offer thermal comfort while taking advantage of natural resources. To achieve its objectives, bioclimatic architecture (arquitectura bioclimatica in Spanish) coordinates the design of the building, construction details, architectural spaces and exterior elements, applying a series of techniques and handling certain factors.
Ways of heat transmission
Heat transfer mechanisms affect the thermal behaviour of a building in different ways:
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Conduction: Energy travels through the mass of a body. Some buildings can lose heat during the winter if their walls are highly conductive. Insulators can be used to prevent this.
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Convection: In fluid materials, energy is transported by the movement of the material itself. Convection can be natural, for example in the case of hot air rising, or forced, such as fans that move the air.
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Radiation: The intensity of electromagnetic radiation of a material depends on the temperature at which it is exposed.
A structure has a high calorific capacity when it is able to store a lot of heat and a lot of thermal inertia when its temperature rises or falls slowly. Ideally, buildings should accumulate and release heat slowly to avoid sudden changes in temperature. Soil temperature changes should also be considered. Its thermal inertia causes the external oscillations to be dampened, and when it reaches a certain depth, the heat remains constant. Many think that this architecture requires increasing the initial investment, but this is not necessarily true.
Location and climate
All the natural and artificial elements of the environment can influence the building’s behaviour. The first study to be done is on climatic conditions and location, considering:
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Temperatures (average, maximum and minimum).
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Rainfall or rainfall.
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Incident solar radiation.
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Direction and average wind speed.
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Slopes of the land.
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Elevations nearby that may block or reflect radiation.
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Influence of nearby rivers, lakes or seas.
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Influence of forests.
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Other buildings or constructions.
It should also be considered that it is possible to intervene by adding or removing vegetation, modifying elevations or creating artificial lakes, for example. The shape and orientation of the building will determine the area of contact with the exterior, the amount of sunlight it receives and its response to wind. Insulating materials and thermal mass seek to optimise the storage and release of heat and reduce sudden changes in temperature. Ideally, a building will store solar heat during the day to progressively release it at night.