How are the streets built in the desert?

SWR2 knowledge Houses for the desert - climate-friendly building in the sand

A luxury district made of concrete and glass has been built in Abu Dhabi since 2008, using renewable energy sources. In Namibia, a German company is building houses out of desert sand for little money, which they process into stones more firmly than concrete according to their own recipes. These inexpensive buildings are primarily intended for poor people. In the USA, too, there are now desert-friendly model houses.

Extreme desert climates require adapted building methods

A third of the earth's landmass are deserts or semi-deserts. It is not known exactly how many people live in deserts; in the Sahara alone there are said to be five and a half million. In the course of history, people have built a wide variety of residential buildings in sandy and stone deserts: from tents made of palm fibers or animal skins to simple huts made of tamped clay to stable houses made of stone.

In doing so, all desert dwellers had to pay attention to one special feature: the extreme climatic conditions of deserts: in most desert regions it is very hot during the day, even in winter. But especially in the winter months it can also get pitifully cold at night.

Dubai - skyscrapers with glittering facades are not climate friendly

Buildings in all desert regions of the world have to cope with the special climatic conditions of deserts. For example in the modern, noisy cities of the United Arab Emirates on the Arabian Peninsula, one of the largest desert areas on earth. The skyscrapers in Abu Dhabi and Dubai, which is just under 140 kilometers away, seem to want to outdo every other metropolis in the world: in height, unusual shapes and pomp. Imaginatively curved buildings have glittering, sparkling facades which, with the help of the latest technology, automatically darken when the sun gets too hot.

Sparkling clean avenues, chic boulevards and super-wide shopping avenues divide the cities into accurate chessboards. In many fields across the city, ultra-modern, air-conditioned shopping centers, shopping paradises - where the Imam calls to prayer over hidden loudspeakers.

Huge buildings have to be cooled with a lot of energy

Professor Schew-Ram Mehra teaches building physics at the University of Stuttgart. The skyscrapers in the United Arab Emirates made of glass, steel and concrete, says Mehra, contradict all the rules of climate-friendly building. The desert is sometimes very hot during the day and cold or cool at night. That is why you need materials that store heat during the day and release it again at night. In the past, people built traditionally with the building materials that were available on site. That was clay, that was bricks and, above all, stones, which on the one hand insulate, but also have a high heat storage capacity.

For climate-friendly building in the desert you need:

  • The right materials
  • A compact design and small windows
  • Good ventilation: To prevent the interior from getting too hot, people built devices a long time ago to ventilate the structure, the housing and the rooms well.

Today's architects in cities like Abu Dhabi and Dubai disregard the tried and tested traditions of building, according to Mehra. This included the use of storable building materials, a construction method that protects against the sun, and natural air conditioning systems that ventilate the rooms well. Since the beginning of this millennium, however, it has seemed as if the President of the United Arab Emirates, Sheikh Chalifa bin Zayid Al Nahyan, had learned from the construction mistakes of the last decades. He wants to cultivate part of the desert around Abu Dhabi in a completely new way and create one of the most ecologically sustainable cities in the world with Masdar City.

The "model city" Masdar City

Chris Chi Lon Wan is a Chinese "guest worker" in Abu Dhabi - like around 85 percent of the population there. At the same time, he is the head of the development team for a new, ecological district in Abu Dhabi: Masdar City. The "model city" is about 30 kilometers away from the city center of Abu Dhabi. It should actually be ready in 2016.

In 2017, however, only about ten percent of the eco-city was: mainly office buildings, a university, student apartments, a few restaurants, a few apartment buildings, a field with solar panels. The rest is still desert, even if it's already leveled flat.

Autonomous cars drive in tunnels under the already completed buildings. They bring people from the parking lots in front of Masdar to the center of the district - because cars are forbidden in the eco-city.

Masdar City - eco-city for millionaires

The already completed buildings in Masdar City are low, no more than two or three stories high, kept in different shades of ocher and are close together. Some are adorned with Arabic ornaments, others contain high-tech elements, such as automatically adjustable slats that protect the interior from the sun. There are solar panels on many roofs that provide electricity.

Despite the ingenious use of sun and wind, Masdar City is not yet energy self-sufficient, as it still draws most of its electricity from Abu Dhabi's conventional grid. But one day - the year 2026 is currently planned - sun, wind and perhaps geothermal energy will supply Masdar City with ecological energy for 47,000 residents. So could Masdar City be a model for other desert countries?

Climate-friendly reconstruction of Aleppo planned

The city of Aleppo in northern Syria, which was largely destroyed by the civil war, is also to be rebuilt. Smaller, simpler, more natural - and more affordable than before. Scientists from World Heritage Studies and the “Climate-Friendly Construction and Operation” course at the University of Cottburg are investigating whether this is realistic.

They are planning to reconstruct the listed buildings in Aleppo as they looked before they were destroyed. The "additional options", for example for energy generation or drinking water supply, should be "hidden" inside the building, because solar panels or huge water tanks on the roofs of listed buildings contradict traditional construction.

Building with desert sand

Two men from Germany want to make it even easier, more natural and, above all, cheaper. With concrete blocks made from desert sand. Schew-Ram Mehra, the building physicist at the University of Stuttgart, is critical of this. For these concrete blocks you need a specific type of sand, says Mehra. The statics cannot be guaranteed when building with desert sand. Gerhard Dust sees it differently. Dust is the managing director at "polycare". The German company in the Thuringian town of Gehlberg was founded in 2010 for a single task, namely to develop and produce special stones in a small test facility. These bricks look like Lego bricks and can be easily put together even by laypeople.

Build like with Lego bricks

Dust is the managing director of "polycare". The German company in the Thuringian town of Gehlberg was founded in 2010 for a single task: namely to develop and manufacture special stones in a small test facility. They look like Lego bricks and can be easily put together even by laypeople. Even by people without vocational training, in desert regions, for example in Africa.

The basic idea, according to Dust, was to create something that would enable a middle-aged couple to build a house themselves, without heavy construction machinery, just with muscle power. But this house is supposed to be stable enough to last for generations, and it's supposed to be so that you can reuse it.

Houses that can be plugged together

What is special about the “polycare” building blocks: They are made of so-called polymer concrete. Instead of cement and water, it contains synthetic resins and chemicals - and the predominant filler material is sand. The "polycare" uses desert sand - which was previously unthinkable. The inventor of these desert sand stones is the mechanical engineer Gunther Plötner. In order to produce them, the inventors from Thuringia made experiments with different types of desert sand.

The company is now beyond the experimental phase and has developed a polymer concrete that is stronger than concrete, insulates well against cold and heat and is not attacked by rain. Another advantage: the individual stones do not have to be connected to one another with mortar. "Polycare" has already "put together" several houses around the world: for example in Namibia. The first factory for the production of polymer concrete will soon also be built there.

Bureaucratic hurdles are delaying the spread of the desert sand building blocks

Desert sand houses like those in Namibia are perhaps more of a model for building in deserts than the luxurious Masdar City. So far, Gerhard Dust and Gunther Plötner are still fighting with politicians, authorities and donors to ensure that houses can actually be simply put together from their desert sand building blocks in every poor country. But at some point it should be ready: Houses are to be built according to traditional building plans, supplemented by modern, adapted technologies, composed of materials that occur in the country, built by the people who live there.
Incidentally, Saudi Arabia has been planning its own fantastic city since 2017: “Neom” - “New Future”. This city of the future is intended to overshadow Masdar City and everything that has gone before. And it will cost billions.

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