With the emergence of sustainable environmental architecture in the present era and the impact on architectural design of buildings, it is necessary to study the effects of sustainable architectural elements on energy consumption. On the other hand, the use of glass and metal facades of modern architecture for transparency and the use of daylight is one of the effective factors in energy consumption. Therefore, due to the fact that one of the most important technologies for saving energy consumption in a building is the facade, the use of double skin facades of environmentally sustainable architectural elements has increased. In the following, we will describe the types of double skin facades and the materials used in it.
Double skin facade structure
Energy consumption
Reducing energy consumption requires the application of new solutions with a sustainable architectural approach. Selecting a double skin facade is a way to properly use energy resources. These types of double skin facade allow natural ventilation through our air intake between the two layers while controlling sound, wind and rain. Its most important feature is its ability to adapt to seasonal needs. The use of double-skinned facades, in addition to being a suitable solution for dealing with issues related to energy loss and climate issues, is a good response to the principle of flexibility in modern buildings. The double skin facade allows the outer shell to be executed transparently and lightly, thus implementing the principle of modern flexibility.
Double skin facade
Double skin facade
Predicting the performance of Double skin facade is not an easy task. Temperature and air flow are the result of a process of instantaneous changes in temperature and fluid flow. These processes depend on the geometry, thermal physics, various combinations of aerodynamic structures of the double skin facade structure, as well as indoor temperature, ambient temperature, wind speed, wind path, absorption and transmission of solar radiation and its angle. The smart shell generally acts as an anti-heat in front of the building, and this has three thermal effects on the building:
1. Most of the day, the temperature inside the smart shell will be higher than the ambient temperature. The low conduction of lost heat and the high conduction of heat obtained in summer depend on the ambient temperature and the levels of sunlight.
2. The extra layer of smart shell glass reduces the amount of sunlight to the inner shell. Therefore, the reflection of the sun’s rays on the building is reduced due to passing through the glass.
3. The smart shell allows the curtain to be placed inside the shell. Therefore, the load of radiation from the window is reduced. Which of these three is more important at a particular time depends on the characteristics and performance of the structure and the complex thermal dynamics between the facade, the temperatures, the airflow in the smart shell, and the outer space.
Facade
Types of double skin facades
1. Multi story: In this method, there are no vertical or horizontal columns between the layers. In cavity ventilation, air flow is done through holes near the ground and on the roof of the building.
2. Corridor façade: Horizontal sections are made for acoustics, fire protection or for ventilation.
3. Box window: In this case, it divides the horizontal and vertical parts of the façade into smaller, independent boxes.
4. Shaft Box: A series of elements are placed in the façade. These elements are connected by vertical strings in the façade, ensuring the effect of a wide range.
Types of double skin facade
Advantages of double skin facade
• Low construction costs that can be obtained by comparing with other projects.
• Sound insulation
• Decreased internal volume
• Thermal insulation
• 5 ventilation systems during the night
• 6 energy storage
• 7 Reduce the effect of wind pressure
• 8 transparent design
• Natural ventilation
• 10 escape from fire
• Reducing energy consumption
The air distance between the two shells is between 80 and 100 cm, but it is important to note that this distance can vary depending on storage, type of ventilation, greenhouse effect and energy consumption. The climate of the building in question is also very important in determining the distance between the two facades. According to experiments performed at a distance of 8 to 148 cm from the shell, it was observed that the final energy consumption depends less on the depth of the shell and more on the type of windows. The performance of two-shell facades differs in different climates. In cold climates, it functions as a heat exchanger that keeps the temperature of the inner layer air close to the temperature of the indoor air. In hot climates, double-skinned façade reduces the shading coefficient.
