In fact, air conditioning is a device that has a “survival” meaning in the summer, especially in urban areas, with few trees, densely populated and crowded vehicles and constructions. However, air conditioning not only costs a large amount of money every month, but it is also a ‘culprit’ of environmental impact. So what natural cooling materials should be used to ensure sustainable architecture?
Air conditioning accounts for 10% of global energy consumption today. In 2016 alone, the use of air conditioners emitted up to 1045 tons of CO2 emissions. This number is expected to increase many times over. According to the International Energy Agency, cooling will account for 37% of the world’s total energy demand by 2050 – an alarming number that causes the greenhouse effect.
The graph depicts greenhouse gas emissions from cooling. Photo: International Energy Agency Forecast of energy demand by 2050. Photo: International Energy Agency
Air conditioners are bad for the environment because they depend on Hydrofluorocarbon (HFC) refrigerants. Despite accounting for only 1% of total greenhouse gas emissions, HFCs are thousands of times more dangerous than carbon dioxide.
HFC emission trends. Photo: Clean Air and Climate Alliance.
Therefore, designing with natural cooling materials can minimize negative impacts on the environment, thereby reducing the need for air conditioning.
Below are some material and structural solutions for passive cooling, helping designers to regulate building temperatures in an energy efficient manner.
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Thermal mass and insulation
Thick materials such as stone, concrete, and earth are considered to be effective assistants in insulation. These alternative materials all guarantee good thermal conductivity, thermal hysteresis, low heat reflectivity and high heat storage capacity.
Cave House in Santorini. Photo: Vangelis Paterakis
Increasing the use of these materials will contribute to effective house cooling such as the unique Summer Cave House in Santorini or the concrete house A-cero Concrete House II, which uses solid concrete walls. to cool the house.
A-cero II concrete house. Photo: Luis H. Segovia
More traditional homes may not use such bulky materials but instead have effective insulation. Usually, the thermal resistance of a material is measured by the R-value. The higher the R-value, the more heat-resistant the material, the greater the insulation effect. Materials such as polystyrene, polyurethane foam, and phenolic foam are all examples of high R-value thermal insulators. That is also the reason why many houses often use insulating film and window film.
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Using available natural ingredients
In addition to the high, thick concrete walls, there are countless designs that are aware of the available materials from nature that have a cooling effect such as the roof of the house, the use of a closed vines system. houses or simply covered ivy. Green roofs are not only aesthetically pleasing but also provide shade, remove heat from the air and reduce heat from the roof.
Notable examples include Renzo Piano Science Academy, California, CPG Nanyang School of the Arts and Enric Ruiz-Geli Villa Bio.
Renzo Piano Academy, California. Photo: Tim Griffith
You can also incorporate a water cooling system to lower the indoor temperature through evaporation and take advantage of cool air flows, depending on the climate.
Ambrosi I Etchegaray’s Spa Querétaro is a contemporary example of cooling a home with a lake. Photo: Luis Gordoa
This method was invented by the Romans early. If you notice, they often design houses around a pool in the central courtyard.
Materials and window placement
Diagram of how different types of windows interact with heat and light. Photo:Courtesy of the Efficient Windows Collaborative
Passive cooling is also easier if you know what type of glazing is right for your home. The lower the solar heat gain coefficient (SHGC) of the glass, the less heat is transmitted and the cooler the house. These benefits can be greatly increased if combined with exterior curtains, which block sunlight from entering.
Even the design of the window placement provides passive cooling through cross ventilation or aligning the windows to facilitate air circulation.
Cooper Scaife Architects’ Leura Lane. Photo: John Wilson
The choice of roofing material will affect the temperature inside the house. According to the announcement of a group of scientists from the United States Space Agency (NASA), measuring the heat absorption capacity of urban roofs on the sunniest summer day in New York in 2011 showed that, while the While a dark roof absorbs approximately 77 degrees Celsius, for a light roof this figure is only obtained at 71 degrees Celsius.
Not only does it absorb less heat than dark roofs, but the reflectivity of light-colored roof surfaces becomes more effective over time. However, this cooling solution can be reduced by dust, weather that causes roofs to black, and exhaust pipes from the building’s heating or cooling system that will make them easy to discolor.
In addition, buffer spaces such as corridors and porches can also protect interiors from sunlight and reduce the amount of heat that hits the house directly.
In general, to keep the house cool, besides choosing the right natural cooling materials, you should consider planting more trees, using tips to cool the room. And if air conditioners are the ‘separate’ item in the house, use them properly.