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Living of the future: energy - the power plant in the house
Living of the future: energy - the power plant in the house
Video: Living of the future: energy - the power plant in the house
Video: Will our electricity come from space in the future? 2023, February

Our houses are insulated to an extremely high quality in order to limit energy losses, and some even develop into their own small power plant. What makes sense, what is exaggerated, which concept is derived for our building and our cities?

Darmstadt's architecture professor Manfred Hegger, Germany's leading energy expert, looked for and found answers - not only in his own planning work, but also in research and teaching. With his students, he won the international "Solar Decathlon" twice in succession - the world's most prestigious competition for energy-autonomous houses. Manfred Hegger died on June 29, 2016 at the age of seventy.

Professor Hegger was a specialist jury member of our architecture competition "Das Goldene Haus" in 2000 and 2007 and was repeatedly available for interviews. In memory of an inspiring architect, here we publish a conversation he had with DAS HAUS in 2014.

Maßstäbe für Energieeffizienz setzte dieses Haus von Manfred Hegger und Team
Maßstäbe für Energieeffizienz setzte dieses Haus von Manfred Hegger und Team

This house from Manfred Hegger and his Darmstadt team set the standard for energy efficiency back in 2007: winner of the Solar Decathlon in the USA.

Photo: Leon Schmitt / TU Darmstadt

Professor Hegger, where will we get the energy to live in the future?

Manfred Hegger: With today's technology, a single-family home can take care of itself. This is possible because the ratio of the living space to the area of ​​the shell can be used relatively cheaply for energy. The roof and walls protect and insulate, but they are also ideal areas for using solar energy. You also have the option of producing energy from the ground via geothermal energy or from the house itself via heat recovery. This makes the single-family home a prime example of how you can - and should - get your energy consumption from the area throughout the year.

Doesn't that quickly become too technical for many people?

We have learned from our solar decathlon houses that a house can be used very well as an energy generator. So far, the group of people who want this has been limited to technology freaks. We have to change that. The cover has to perform its tasks with little maintenance. And the technology should be designed in such a way that it informs its residents about its effects and yields.

Playful access and easy operation are important to me. All age groups should be able to handle it intuitively, ultimately like using a switch. Interested parties should also be able to work with the house via interfaces. The best way to do this is with electrical energy. Solar thermal is more difficult to handle because it is a complex system with liquids. And because, unlike photovoltaics, these collectors cannot do much with diffuse radiation.

Some companies already offer controls of the solar system via the surface of a smartphone. Is this the right way?

This is an intermediate step. In the near future, many windows or doors will be equipped with touch-sensitive sensors - or we can simply control them with gestures. Even the simple switch continues to be justified. We will experience a lot of new things there. We have to pay attention to our privacy: data about the behavior of users does not belong to the public. That's why I'm against internet solutions. On the other hand, it would be wrong to demonize the technology as a whole because of data protection.

Can apartment buildings in the city also contribute to energy generation?

Yes, absolutely. Problems are still storage and exchange. The goal would be that entire city districts can exchange energy with one another. I advocate a smart grid, preferably with a storage facility nearby. For example, the energy bunker in Hamburg-Wilhelmsburg does this for its neighborhood. The idea of ​​networking also creates a new social awareness. You don't always have to do something like this alone: ​​You can also do this by becoming a member of an energy-producing cooperative.

Does energy generation also affect the location of the house and its shape?

Ten years ago, many people still thought that to use solar energy, we would have to turn entire neighborhoods south. We don't have to. We also don't build the houses at greater distances so that the facades are free of shading, but we want to give people in their apartments at least a few hours a day of sun. The human is the center of attention.

With the low prices for renewable energy systems, the energy supply no longer has to achieve maximum efficiency. We can fully cover roofs, even the facades - even on the north side, because the diffuse radiation makes a significant contribution. We measure that again and again. Even on overcast days and at light twilight, the house still has 15 percent of its maximum yield. You get more freedom in design by maximizing the energy-saving area. Today I can produce electricity at home at prices that are significantly lower than the costs that the power plant charges me.

Does the color design also have any meaning?

Color plays a big role. Bright areas radiate heat, dark areas heat up. Solar systems are necessarily dark. This has to be considered, especially in times of global warming. There is a lot of discussion about the extent of the insulation. Some already speak of the insanity craze? I don't stand naked on the street at night in winter. I need clothes. In the house we call it insulation. At some point the insulation becomes too much, then I sweat. A balanced relationship is therefore necessary.

When we received the first thermal insulation regulations in the early 1980s, we had no other option but to insulate. In the meantime, however, we can directly generate energy with houses. Now we don't need walls that thick. In addition: new mineral materials have better insulation values ​​than anything we have known so far. New techniques and new designs emerge. We should also develop the storage further, otherwise we will push too much energy into the grid or lose too much.

What storage do you mean?

Completely old and completely new technologies. Very old = " are earth building and brick building. But not the brick that only insulates. But one that insulates and stores, i.e. one with enough mass. New technologies would be the so-called phase change materials. These are materials that can store a lot of energy when their physical state changes from solid to liquid and then slowly release it again. In the temperature range that interests us, i.e. around 23 or 24 degrees Celsius, this works very well with waxes or with salt hydrate solutions. It can be used to achieve enormous storage capacity in plaster of one centimeter in thickness or in plasterboard.

These materials can be processed normally because the waxes are microencapsulated. We have built this into our decathlon houses: the wooden houses react in a similar way to solid houses. Unfortunately, it is currently still too expensive, but it is already on the way to an inexpensive industrial product. But a two to three centimeter thick clay plate, attached on the inside, already has a good storage effect.

Ein Plus-Energie-Haus für 74 Parteien baut Hegger in Frankfurt
Ein Plus-Energie-Haus für 74 Parteien baut Hegger in Frankfurt

In Frankfurt, Hegger's office is building a plus energy house with the latest technology for 74 parties. Researchers are accompanying the project. Photo: HHS Planer + Architekten AG

Bauen für die Zukunft
Bauen für die Zukunft

Photo: Callwey Verlag

Our tip: A more detailed version of this expert interview was published in our book "Building for the Future", which we published on the occasion of the 65th anniversary of the house. In addition to further interviews, you will also find specific planning tips, the latest trends in the construction industry and more.

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