Rather than inventing high-tech green solutions, we need to revive ancient methods of fueling and heating our homes.
Last Winter I spent several months covering piping hot copper piping with clay, managing to get a considerable amount on my body and up my nose, because apparently my clumsiness defies gravity. I was living in a “Nature Community” in Eastern Germany, where dozens of modern-day hippies had taken over an old Soviet-era hunting hotel, and were converting it into an eco-community.
Part of this involved installing in-wall heating, designed so that a network of hot water pipes lacing the walls diffused warmth into the thick layer of clay, which then radiated heat throughout the whole room. It’s a technique known as Hydronic heating. Outside was brutally cold — a trip to the shops felt like walking through a blizzard, drops of water freezing on your eyelashes. Inside those clay walls, though, it was toasty.
The general atmosphere of the community — yoga, massage, feeling circles — may have been New-Age, but this kind of Hydronic heating revives a technology which goes back thousands of years.
Romans — after having conquered vast foreign territories and realised that Bath was somewhat chillier than Bologna — are credited with having invented the first central heating system. It worked by channelling hot air from a furnace through pipes placed behind walls and under floors. Homes, villas, and other buildings in the Roman Empire were heated this way. Cistercian monks picked up on the technique again in southern Germany in the 12th Century. They diverted rivers to feed into their plumbing, which included a heating system based on hot water flowing through underfloor channels.
By using water instead of smoke, the Cistercians increased the effectiveness of the system, as water is a more effective heat exchange agent than air. The water in the pipes doesn’t even have to be heated to a very high temperature — it can be less than 30°C. This makes the Hydronic heating system very energy efficient — roughly 15 per cent more so than standard radiator systems, according to The Scientific American. Plus, since the heat is uniformly spread out, you can crank the thermostat down considerably.
Sometimes inventing looks a lot like remembering
As high-tech, smart solutions for limiting our energy consumption multiply, traditional and efficient methods risk being forgotten. Yet Hydronic heating is just one example of how low-tech, millennia-old techniques can play an important role in going green. Sometimes inventing looks a lot like remembering.
Throughout the world and throughout the ages, burning dung has been used as fuel in the home. It’s even mentioned in the Bible — “And you shall eat it as barley cakes, and you shall bake it with dung that comes out of man,” reads the Book of Ezekiel. An estimated half of the world’s population, from China to Kenya, Guatemala to India, still cooks over dung fuel stoves, and that figure is likely to rise as deforestation increasingly means that dung is the only fuel available.
“And you shall eat it as barley cakes, and you shall bake it with dung that comes out of man” — Book of Ezekiel
Readily available and cheap, animal dung has many advantages for use as a fuel, but it also has downsides. Burning it is often smokey and inefficient as the stoves used don’t optimise the energetic capacity of the dung. This is one place where innovation is needed to improve on an age-old technology — especially important in the face of two million women who die every year because of lung-damage due to smokey stoves. Yet there has been very little time given by scientists to designing better ways to use this fuel.
That is starting to change, as companies turn to waste and excreta — rebranded as “biomass” — to produce energy. Toyota is scheduled to open a power-plant in California capturing methane gas from cattle manure to generate electricity and hydrogen. The plant is expected to have the capability to provide enough energy to power 2,350 average homes daily. Meanwhile, Israeli company HomeBioGas has developed garden biomass factories that convert organic waste into methane gas and liquid fertilizer. About half the size of a car, they resemble green tents with funnels on their roofs. Every litre of waste inserted can create enough gas to cook on a high flame for about an hour. On average, HomeBiogas produces 2–3 hours of cooking gas each day — enough for three meals. This can save up to 6 tons of carbon emissions a year.
Modern technology can play a valuable role in giving traditional methods a make-over, using them to turn our homes into micro-power stations, cutting carbon emissions by generating a significant proportion of our heating and hot water needs ourselves. And this isn’t all about technology — a lot of it is about design.
The charcoal heater that brought Japanese families together
During the 1970s petrol crisis, faced with the rising cost of imported fuel, Japan made a shift back to a traditional way of keeping warm in the winter: the “Kotatsu”. It’s a low, movable table with a charcoal heater underneath, and a thick cloth or quilt placed on top to trap the heat. The whole family slides their legs under the table, sitting on the floor. Beyond saving fuel, a New York Times article from 1979 notes that the shift back to time‐honoured heating methods had a social impact too, “helping to restore the lost togetherness of the modern Japanese urban family”, as everyone would come together to huddle around the Kotatsu on cold winter evenings.
More than a feat of technology, the Kotatsu is a feat of design. The thick fabric traps the warmth under the table, and back when traditional Kimonos were worn, it would travel up from the bottom to warm the entire body. Similarly, European homes long held four-poster beds or hooded chairs, designed to create warm microclimates in cold houses. A hooded chair could have the heating power of a thick coat.
Design has long been an essential factor of heating and cooling homes — which is why regional architectural differences are so largely linked to climate differences. Fittings that have become an indissociable image of a culture can be traced back to very real climatic needs: the Greek Portico is a response to the sun and rain, the high ceilings of Roman basilicas are to make worshippers comfortable in a hot climate.
To be convinced of how important architectural design is in ensuring a building’s heat — or otherwise — you just have to step into the walls of my old university, l’Université Pierre et Marie Curie in Paris. The building, aside from being infested with asbestos, had originally been designed to be built in Mexico. When you walked through the central quad, air rushed between pillars and created a freezing cold draught, which was surely a brilliant plan for Mexico but is somewhat less pleasant on a snowy Paris winter day. In the face of ever more complicated technology, we sometimes forget that simple design can have a big impact.
Rushing into the future, confusing progress with ever more complicated technology, is what got us into this mess in the first place. To get out of it, we need to reinvent low-tech solutions to reduce energy consumption in fueling and heating our homes.
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