My favorite kinds of “green” solutions are the low tech ones based on technology that’s been around for thousands of years. When it comes to heating and cooling buildings or even whole cities, ancient solutions are often available, and are almost always much cheaper than an energy intensive alternative like air conditioning.
Last week, I was treated to a tour of Masdar City in Abu Dhabi (see a little background and the fun we had on the PRT here). Although the development is brimming with high and low tech green building attributes, one of my favorites was the wind tower, pictured here.
The tower, rising well above the rooftops of any neighboring buildings, is not a turbine designed to generate electricity. Rather, it’s a simple empty cylinder with adjustable louvres at the top.
The primary purpose is simple: a tall cylinder is capable of provoking a convection current as hot air rises simply by standing there. This creates a natural current of air flowing from the street level of the city and up out the top of the tower – the breeze it creates pulls hot air out of the city and makes life in the plaza below considerably more pleasant.
The genius can also be extended to work in the other direction. By adjusting the louvres, the tower can be “turned” to catch any prevailing winds and therefore “pull down” flowing air, sending it cascading into the plaza to provide a breeze which lowers the perceived temperatures by as much as 5 degrees celsius.
It works particularly well because of the deliberately narrow streets of Masdar City – designed that way to minimize the amount of direct sunlight that hits them. Being compact and narrow also means the breeze can be channeled more tightly, making it faster and more effective. Imagine a feature like this used for outdoor malls in Las Vegas or Phoenix!
But there’s a second, more subtle use for the tower:
Since it’s a totally experimental city, Masdar wanted to put some time and effort into understanding the social benefits and compromises of living in a zero-carbon city. The city will ultimately track and report on all aspects of its energy and water use. This data will be used to learn what is and what is not working, and to make needed tweaks.
Some data will be shared publicly to give the residents an idea of where energy is being wasted and where kudos have been earned. The idea isn’t to single anyone out. Rather the question is thus: if the residents of the city are aware that they, collectively, are doing a good job on a particular day, will their behavior change? Or will they selfishly ignore the warning signs?
Enter the wind tower’s subtle signal: LED lights run up each of the three legs of the tower. When they are green, the city is running at better than it’s daily goal for energy consumption, when the lights are red the city has exceeded it’s limits by some amount.
If the tower turns red on a particular day will people scramble to turn down their a/c or lighting? What if there were some kind of collective consequence? Once the city is more populated, the answers will start to become clearer, but for now, the grand experiment awaits…
Full disclosure: Masdar covered travel expenses for this trip to the World Future Energy Summit.