4 Out-There Designs to Cut the Carbon Footprint of Heated Sidewalk Cafés
Jacqueline Feldman wrote back in February about the showdown over Paris' café terraces, a fierce battle that has pit against each other smokers who would like to stay warm outside (alongside the restauranteurs who want their business) and environmentalists who see heated sidewalks as a giant waste of energy. The tension has been particularly pronounced in Paris, a city famous for its plein-air people-watching. But the trouble is also arising anywhere anti-smoking laws are pushing people out of restaurants and bars and onto the sidewalk.
The resulting challenge is an engineering one: By definition, these outdoor terraces must be open-air – otherwise, you couldn't smoke in them. But that design requirement also means that it's nearly impossible to efficiently heat these spaces. (We'll pause here for a moment to also acknowledge that this is very much a first-world design problem.)
It's possible, though, that technology could bridge these warring factions in Paris and elsewhere, allowing cities to keep both their smoking havens and their environmental credibility. The city of Paris submitted this problem to the LLGA | Cities Pilot the Future challenge, which for the past four years as been trying to match urban conundrums with innovators all over the world. This year, the challenge corralled calls for solutions from 22 cities to problems ranging from health inequality to traffic congestion. Researchers unearthed a suite of solutions for each one, and the companies and organizations behind them are now vying to implement real-world pilot programs in the host cities. The winners will be announced in San Francisco in May (and we'll plan to look into a few more of these solutions before then).
Paris's plea for technological help with its café problem solicited some pretty interesting ideas, from the self-sufficient "Urban Parasols" seen above to photovoltaic devices embedded in "SolarFloors." That second idea comes from a company called OTEM2000, which is envisioning a combination of photovoltaic glass tents and energy-producing "smart floors." Some of their sketches:
The "Urban Parasols" would offer instead a semi-enclosed space for outdoor diners and drinkers (using "thermodynamic solar panels and space blanket insulation"). The same concept could also theoretically enclose bus shelters or other public plazas.
This more straight-forward idea, from the Danish company Mensa Heating, would turn café tables themselves into heaters, providing infrared under-table heating directly to your extremities for "a more effective method for controlling core body temperature."
One other idea comes from a company called Dext Heat Recovery, which proposes that if restaurants can't efficiently heat their terraces, at least they could offset the waste by capturing more of the excess heat produced in the kitchen. As Dext explains it: "Our heat recovery plate is installed close to the main heat source within the kitchen, either directly behind a chargrill or cooker, or within a canopy. The heat is then absorbed by the plate and transferred into a sealed water circuit, which is circulated through a coil in our buffer cylinder for hot water generation." A little animation of the process:
Of course, you could also just put on a jacket. But as general appreciators of sidewalks, we can understand why people would want to linger there even in the dead of winter.