2024-01-04 20:04:11
A visit to The Green Village, the open-air laboratory of TU Delft, offers hope for the (green) future. All sustainable innovations for the built environment are given space here.
It starts in the toilet in the reception and office area. There are two stickers on the double flush button: a red one that says ‘6 liters of water’, a green one with ‘3 liters of water’. And so you consciously press one of the two – preferably the green one. Sustainable discoveries can be that simple. This is also evident on the rest of the site.
The Green Village is a mini-neighborhood where experiments are conducted with sustainable innovations and techniques for the built environment. An open-air laboratory, part of TU Delft, with houses, offices and streets. Thirteen people live there, students and ordinary Delft residents. These are important, because what do citizens think about them? “We even employ psychologists,” says Marjan Kreijns, director of The Green Village. More about that later.
Making terraced houses future-proof
We are standing next to a row of 1970s homes, built in 2019. Not exactly what you expect in a field lab for a sustainable future, but houses from that period must be future-proof, says Kreijns. “There are 4.2 million terraced houses in the Netherlands. They are a big challenge. How are we going to make all those homes more sustainable in an affordable way and adapt them for the energy transition?”
“Houses with low energy labels, no insulation and single glazing,” Kreijns explains. “A housing association from Friesland and a Frisian construction company built these three houses – a reflection of the Dutch housing market – here and said: ‘get started with them’. However, the ideas had to be scalable and affordable.”
Various solutions for sustainable renovation are now being tested. With solar panels, heat sources, insulation options and innovations for a healthy indoor climate. Because insulation and ventilation can quickly become at odds with each other.
Shower with old shower water
Another challenge: recovering heat. For this purpose, one of the houses has a system for circular heat supply from a Delft startup. Heat from the drain water from the washing machine, dishwasher and shower is thus reused. In another home, a shower system has been installed that immediately produces hot water from the tap – rather than liters of precious cold water disappearing into the shower drain before it is pleasant enough to step under it. How is that possible? Heat from the previous shower is stored in an insulated vessel, a kind of thermos flask.
Another test case: in the corner house, an exterior wall is fitted with moss concrete. Moss will soon grow from the spores and some green blades can already be seen. That is not only beautiful, moss concrete also helps against heat stress due to evaporation, it filters particulate matter and captures CO2. The same applies to the grass that grows in the semi-open green stones in the parking lots opposite the houses.
Kreijns: “Typical something like that where you think: why isn’t this already available throughout the Netherlands? It looks nicer than those gray parking spaces and is also better for the living environment.” The best solutions have now been applied in WoonFriesland’s social housing, and the rest of the Netherlands is already following suit.
Fewer rules
And so in these homes, offices, streets and gardens there is a coming and going of experiments. Researchers, students, entrepreneurs, start-ups, citizens and the government work together here. Ready with an experiment? Then room must be made for the next one. 160 projects have already been reviewed. The Green Village is part of TU Delft and is an independent foundation with no commercial interest.
A big plus: this testing ground has a unique, regulatory-free status. Construction is allowed here without permits. Some innovations do not (yet) fit into the existing regulations, which is why the Ministry of Infrastructure and the Environment has made an exception.
The focus is on three topics: sustainable construction and renovation, the future energy system and the climate-adaptive city. Kreijns: “Something is being tested in every nook and cranny. Many innovations and prototypes go back to the drawing board, for example to make them more user-friendly.”
These include major inventions and smaller ones, such as bee hotels that can be attached to lampposts to increase the population of wild bees in cities. This includes testing whether the light from the lamp does not disturb the bees. That doesn’t seem to be the case.
“And here is a nature-inclusive shed, with bird nest box, insect box, rainwater buffer and green roof,” Kreijns points out. “One such shed may not make much difference, but if a housing association installs it at every house, it really means a lot for biodiversity in a residential area. Fortunately, many housing associations and municipalities come to look at this.”
Innovations surrounding the energy transition are more complex and technical. According to Kreijns, we need to move towards more local energy systems in the Netherlands. To energy hubs, where as much energy as possible is generated and used locally. In this way, neighborhoods can become partly self-sufficient and the energy grid does not become overloaded. “Then you need storage. For example in heat buffers, batteries and hydrogen.”
Hydrogen production on solar energy
We are now standing in front of a kind of container containing a group of red cylinders. Kreijns explains what we see. “Hydrogen is stored here under high pressure. The process is as follows: in the summer we generate electricity with solar panels on the houses. The surplus of solar energy is partly stored in batteries and partly used for the production of hydrogen through electrolysis.”
We are witnessing a first: in a makeshift office, the chief engineer is trying to convert homemade hydrogen from The Green Village into electricity using a fuel cell for the first time. To discharge, he briefly rolls his office chair back to get away from the control panel, but within a few seconds he is staring at the screen again. It works.
Kreijns is also delighted and emphasizes that the regular safety and environmental requirements apply to working with hydrogen, including at this test site. “As a university we want to find out everything, anyway. We have no judgement. We do believe in sustainably produced hydrogen. All alternatives are absolutely necessary for a sustainable energy supply.”
The water street, the climate district and the heat square
Everyone can walk around here during the day and look. There is an information board for each project. For a climate-proof city, research is being conducted in the Waterstraat, the Climate Quarter and the Hitteplein. Because during dry periods the city feels stuffy, during peak rainfall the water cannot escape. That is why different types of paving are tested here, as well as green roofs and facades, underground water reservoirs and reflective roof insulation that works as a kind of heat shield. Because the Dutch climate is changing.
The weather shows more extreme rainfall, stronger storms and longer periods of drought and heat. To demonstrate this scientifically, we collaborate with the KNMI. Because no matter how experimental and out of the box it is here, it also applies: measuring is knowing.
One of the most surprising innovations has to do with heat stress in the city. The perceived temperature appears to be lower when there is a breeze, which is why a breeze is generated on the Hitteplein. How? Through strips of paving between the greenery. The stones are black and therefore become much warmer than the green. The strips run from narrow to wide, with about a meter difference, which causes the air to move and creates a breeze.
Since the war in Ukraine and the rise in energy prices, they have noticed much more interest here, says Kreijns. “People’s behavior is a major part of the energy transition. For example, people would like to make their home more sustainable, but apply for a subsidy, that is so complicated. The climate psychologist from TU Delft calls this the ‘hassle factor’. In this way, we provide feedback to ministries about which laws and regulations are hindering.”
A consolation: in the foreseeable future, citizens will be treated to something simple: inductive charging of the e-bike via the stand, on a special paving stone. Put the bike down and you’re done. Wireless and no hassle with batteries. The prototype is here.
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