The New Republic

Dayo,

I can appreciate the earnest you have for sustainable design. It's something that many architects, especially the younger crop of under-40 that have grown up with thinking about sustainable design issues.

The complexities of which I deal with on a daily basis with the projects I've worked on and fought to keep even simple things like operable windows and daylighting controls.

I've mixed feelings about LEED and it's tendency to let architects, engineers and clients think about sustainability as a check-list. It's a start for sure but not the be-all-end-all of what is or can be considered environmentally sustainable and efficient design. Many architects are pursuing these goals above and beyond LEED because they see the limitations of LEED.

While I can understand you're wanting of a czar, I'm not sure what that would accomplish other than add a cabinet position that would achieve little. Today's energy and building codes in the US are updated and revised on almost a yearly basis with each local and state jurisdiction adopting them and amending them to local needs. Much as a top-down approach for something like LEED would be great, the downside of LEED is that it's too prescriptive and yet not flexible enough for regional issues.

For architecture to be truly sustainable, energy & environmentally efficient it needs to go beyond just LEED but it needs to respond to the local needs of where it is built, respond to the regional and local climates and in some instances the micro-climates that are created in urban areas. LEED is starting to address these very issues but still has much ground to cover. Many architects are questioning the need for super-efficient and air-tight structures and developing more breathable structures that are more efficient and healthier as well.

My frustration has been trying to convince both the people I've worked for and the clients I've served that sustainability done right is better in the long run and I've been trying to do this since I finished my undergrad degree in 1996. I know I'm not alone either. But people are finally coming around and I must say that it's the younger generations that are pushing it along as well as pioneers and those that have made great efforts to get the message out.

As you've pointed out and I've posted elsewhere, the older building stock presents the biggest challenge to addressing energy demand by buildings in the US. Even by today's standards, buildings of 10 years ago are practically obsolete when it comes to building sciences and material breakthroughs. So we've got a long hill to climb. The good news is that as more people come on board, the state of the built environment will improve exponentially. Five years ago you couldn't even get clients to spec recycled carpet. Now they request it.

But as to your conundrum about the need to photosynthesize I suggest getting outside more. Even on a cold day the sun feels blessedly better on your face outside than it does through a pane of high-performance glass.

- singlespeed

July 18, 2008 at 12:18am

Hehe.  I just bought a 100-year-old house.  So much for environmentally conscious construction.  At least it's within walking distance of mine and my wife's work.

Nada who art in nada, nada be thy name...

- aeromonas

July 18, 2008 at 9:47am

As for solar concentrators, I've often wondered about this myself.  Parabolic mirror arrays are cheap as chips.  Given the cost of photovoltaic cells, it would seem viable on the face of it to concentrate light on a cell with lenses or mirrors and thereby increase the energy output per cell.  I'm sure that it's a case of diminishing returns as you concentrate the light further and further.   You wouldn't have to go up all that many multiples before the heat generated would be prohibitive--you'd melt the solar cell.  But maybe they're getting better at making solar cells that can handle more intense light.  

- aeromonas

July 18, 2008 at 9:55am

If you want to check out some cool building tech, look here: http://ravenbrick.com/ I have no ckin in the game, but these guy shave invented a nano material that reflects when it is hot and transmits when it is cool. Sheath a building in it and you automatically heat or not with sunlight.

- dbhuff

July 20, 2008 at 9:25pm

In a typical solar roof and field, about 60% of the installed system cost is "balance of system" today. That means, if the solar cells were free, the system would still cost 60% of what it costs today. However, thats for a typical silicon system at ~18% efficiency. Start using lower efficiency systems, even with the same layout, and ... that balance of system cost (connectors, wires, inverters, pedastals, etc) goes UP inversely with the drop in efficiency. Conversely, the approach of CPV or Concentrated PhotoVoltaic is to use complex optical systems to provide high concentration (500x or more) onto very efficient cells (>38%). Here the hope is that the balance of system costs of this complex optical approch will be less than the savings of a typical cell vs the fancy triple junction cell. In the end, the amount of energy delivered per square meter is a (relative) constant, and what differs is the areal efficiency of the system.

Now, to our windows. They provide some nice features: the dyes absorb over a wide range of angles, given the intercepted solar flux, and still transport the power to the edges. But they also still allow some light to be transmitted. So the conversion efficiency is unknown. Then they talk about putting solar cells around the edge of the window. This is not the most efficient from a manufacturing point of view, and electrical connections -- "balance of system" -- costs could be high. Furthermore, since windows are rarely oriented towards the sun, there's a raw loss of intercepted solar flux. So the real question about when these windows would be economic is much more complex than the authors would have you believe.

Cross posted to my blog at http://555nm.blogspot.com/

- dbhuff

July 20, 2008 at 9:59pm