A 22-storey apartment building for which all energy is generated by humans? No problem, according to Utrecht research. But then you have to work out for hours a day, you are not allowed to take a hot shower so often and you have to like the smell of sweat.
On the Utrecht Uithof, the striking Willem C. van Unnik apartment building immediately catches the eye because of its height and the enormous logo of the university on the roof. This 22-storey building can be run entirely on human power. Artist Melle Smets and investigative journalist Kris de Decker of Lowtech Magazine came to this remarkable conclusion. .
“We want to start a discussion about sustainability and show how difficult it can be to generate energy,” says Smets. Their research is part of a broader program, the zero footprint campus , to investigate the sustainability of Utrecht University.
Gravity battery
Most notable is the muscle power plant the duo devised for the lower floors. Here are all kinds of fitness equipment. Students work up a sweat here on home and cross trainers, a running wheel and spin bikes. “They generate the energy for the entire building,” says De Decker.
But not all power is consumed immediately. Do the students produce more energy than they use? “Then we use a smart storage system in the elevator shafts,” says De Decker.
In the plan of the two, all elevators, except one, have been removed from the building. Because you might as well climb stairs and it saves electricity again. An ingenious system that forms a so-called 'gravity battery' will be installed in one of the shafts. “The elevator shaft is filled with water and a heavy weight. The fitness equipment pumps water into the column, where the elevator used to go up and down,” says De Decker. The liquid comes under pressure. This ends up in a pressure vessel, which serves as a storage reservoir. As soon as you need electricity, you use that water to drive a turbine.
In this way you use the water as a kind of battery, Smets and De Decker indicate. “The idea is not new. It was invented more than a hundred years ago. It has been used in the past in several cities in England," says De Decker.
Cold beer
However inventive and clever that storage may be, it does not make for a lice life. Whoever wants to live in this flat has to work hard. How long do residents have to work up a sweat to generate enough energy? “If they exercise for more than three hours a day, they can prepare hot food, drink a cold beer and take a shower once every three days,” says Smets.
Taking a warm shower in particular consumes energy, which surprised the duo somewhat. “Charging devices such as laptops and telephones takes much less energy,” explains De Decker. “If you are satisfied with flushing the toilet, cold showers, a refrigerator, telephone and laptop, then 1.5 hours a day of fitness is sufficient.”
But what if the fitness room is freely accessible? So that local residents can exercise for free and thus provide electricity? “That makes a big difference and is tempting, but then you probably create less solidarity,” says Smets.
Explosion hazard
The fitness players do not only produce electricity. They also provide warmth. The temperature rises sharply in the muscle power plant. “This warm air rises and we make good use of it,” says De Decker. “It is distributed throughout the building via a network of pipes and heats the homes.” But isn't that air dirty? “It will indeed not smell too fresh, but it saves energy and is sustainable.”
In addition, Smets and De Decker propose vacuum toilets that work without water. Turds and pee are then sucked up instead of flushed. “It is a nineteenth century invention, which has been applied in Leiden and Amsterdam, among other places,” says De Decker. “It was a shame to flush all kinds of valuable minerals through, they thought. You can connect the vacuum toilets to a biogas installation. We store it in a fermenter in the basement and you can use it to make gas for cooking or heating water.”
There are still some snags. There is a danger of explosion, says De Decker. In addition, it can smell. “It is a kind of living creature, you have to maintain it well.”
Extra pressure
These are all interesting applications that the pair came up with. They excel with a surprising simplicity and inventiveness. But it's not really practical at all. Do the students really all exercise that much? Are energy chore schedules necessary? What do you do if someone takes a hot shower for a long time?
Those are valid questions, the two say. To experience what it would be like to live in the flat they had invented, they went to sport for hours every day. “We wanted to experience it firsthand. It is terribly heavy”, says Smets.
They like to see their plan implemented, but they also understand that there are serious doubts about its feasibility. “We especially want a discussion about sustainability and energy use,” says Smets. The university aims to be energy neutral by 2030. “But their plans are very vague. It will only be thirteen years from now and that is currently not creating any extra pressure or new measures to become truly sustainable.”
In their plans for the flat, De Decker and Smets show how difficult it is to make just one building energy neutral. “Of course we also know that it is just a drop in the ocean,” says Smets. “But we especially want to let people experience and show that energy doesn't just come from somewhere and that you have to make sacrifices for sustainability. Our design makes you more aware of that.”