Could Green Walls Do the Job of Cooling Towers?

[M II A II R II K]

Could Green Walls Do the Job of Cooling Towers?


AUGUST 8, 2014

By SARAH LASKOW

Read More: http://nextcity.org/daily/entry/gree...-yale-research

There’s a reason that green walls show up most often in high-end office buildings and trendy condo developments: Right now, they’re a luxury. As nice as they look, their main benefits — reducing a building’s need for heating and cooling, filtering the air, and providing a place for birds and insects to live — don’t save enough money to justify the cost of installing and maintaining them. Keeping a garden beautiful on the ground is hard enough; it’s that much more complicated — and expensive — to keep a vertical garden thriving.

- But a team at Yale University’s School of Forestry and Environmental Studies is working to create technology that could help justify the cost of green walls. These walls would not just passively cool a building but would actively reject waste heat, serving the same function as bulky cooling towers do now. Heat-rejecting walls would still require plenty of maintenance, but they’d serve a function that companies already pour money into. --- “It’s not solving the problems of green walls systems,” says Alexander Felson, one of the project’s principal investigators, who directs Yale’s Urban Ecology and Design Lab. “But we are redefining their function.”

- This summer, the National Science Foundation awarded the team $299,960 from to expand on the work already done and create prototypes of these multi-functional green walls, first with a series of greenhouse experiments. They need, for instance, to calibrate the temperature of the water that runs through the green walls — it can’t be so hot that the plants die — and determine which plants will most easily thrive in this environment. Eventually, they’ll be field testing and are looking for a client who’s up for the experiment — and who, ideally, has enough existing cooling capacity that the heat-rejecting green walls will be redundant.

- As with most green technology, one of the main challenges this idea faces is scaling it up to replace the current system. Starting with a project like a big-box store will likely be easiest; heavier industry will have to come later. Adding the regulations of an urban area creates another level of complication — and means it’s unlikely that the first demonstration will be in a city. But, if the technology works, Felson says, it’s not a huge leap to imagine integrating it into a network of urban public spaces. There’d be a reason for a private owner to pay for the maintenance and upkeep; at the same time, it could cater to public use.

- Think, he suggests, about Paley Park in New York City, a pocket park tucked into midtown, with a waterfall closing off the back of the small space. “That waterfall could be what we’re talking about here,” says Felson. “It could be rejecting heat and creating a microclimate for people. Think about different scales of that for the city and where it could fit.” Instead of functioning essentially as an amenity in luxury buildings, heat-rejecting green walls could just become part of the landscape.

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