Michelle Addington, Architect: urban heat island

7620: “I think the urban environment is in some ways very much the smart material which forces you to think about things at a different scale and different behavior. When we start looking at sustainability from the urban standpoint we are forced to ask very difficult questions. We know that density and the increase in density that you have in the urban environment de facto reduces per capita energy use. And yet at the same time it introduces another series of consequences. So trying to balance those things that are good about the city; the reduction of transportation, the reduction in square footage per person, the shared services that are quite wonderful. With the very negative consequences which is sort of the problematic albedo, the impervious surfaces, the collection of concentrated pollutants. There’s so many things that are quite negative about the city. I think it forces us to ask very, very deep questions about what really will make us sustainable and I’m not sure I know how to go about answering some of those questions. I think they’re very difficult questions. I don’t think they’re about looking at buildings as individual heroic solutions; the green skyscraper sort of misunderstands it’s relationship and it’s inter-connectiveness with everything around it and we can’t begin looking at these things independently, we can certainly look at it independently in a rural area , but once we’re in an urban environment it’s no longer about the single solution. It’s like whatever you do, it’s got to improve the situation for the great environment surrounding it. but I’ll give you an interesting example of a possibility I didn’t think of, but one of my doctoral students did. Her interest was taking smart materials and understanding how to leverage very small phenomena at an urban environment level. And so her name was Nari Phenuatana and she was looking at urban heat island. And of course what we know about urban heat island, and of course it’s a problem that’s growing dramatically, so much of the development of our urban centers is taking place closer and closer to tropical zones. Those are also the areas where things are going to be even denser than they have been in other places. On the other hand, places like London now are very concerned about urban heat island. So it’s something that is starting to encroach more and more on urban cities. Well, her thought was if you can’t operate the phenomena at their scale, what would be that appropriate scale in an urban environment and the rules that we have to prevent urban heat island in an urban environment are rules that have to do with the spacing of buildings and their relative height. Fine, if you’re able to build a utopian city, not at all reasonable or practical for cities that exist and cities that are rapidly densifying. We’re not at all in control of those parameters. So her approach was what if I changed a small property on the surface so that it interacted differently with solar radiation. And so in her dissertation she looked at certain surfaces of buildings in very dense urban areas and that by manipulating certain properties on the façade and it might be something as imperceptible as a coating, it might be a texture, a paint color, a film on their glazing…that she was able to sort of mitigate the effects of urban heat island and basically have dense buildings exchange…and they’re very tightly packed and they’re very high….exchange their heat with the environment as if they were spread out. Based simply on a manipulation of the texture. And even more importantly, she discovers you only have to do it at a couple of floors. Just at the upper floors and then you have a real impact.”