‘Gimme Shelter’ with Daniel Gehman: Aggressive Passive
- Jun 16, 2009
At least out here in California, “building carbon neutrality” is the new black. In this curious epoch, while we are all waiting to see who will build what next, I have heard it speculated that the “green” movement will fade to a mellow chartreuse until it is clear where the money will come from for new developments. Mmmmm . . . maybe not so much.
Most of what I’ve been hearing suggests that the high performance/resource sensitive sensibilities (some folks still say “sustainable,” but I find the word inaccurate and highly charged, so try not to use it) are actually gaining momentum during this period of economic mayhem. Without offering a judgment on the value of that, there’s one thing of which I am certain: the first buildings out of the blocks when the pendulum swings in earnest will have a significantly different appearance in addition to their significantly different mechanics.
We will usher in a new awareness of our structures’ relationship to the sun, particularly here in the coastal desert environment. With business as usual, we could continue to design a moderately dense community with two or maybe three buildings as the key components, rotating them on site as necessary to optimize circulation and yield, but not really changing the “architecture” from face to face. This has gone on for years and years.
However, as we begin to pursue the new holy grail (I say that without cynicism) of “zero footprint”, it will be necessary again to embrace the low-hanging fruit of passive solar design. Why? Well, as the baseline for building energy consumption continues to drop, the first response has been to raise the efficiency of the HVAC and lighting equipment, incorporating higher SEER units, motion sensor light switches, and of course, the ubiquitous swirly fluorescent light bulbs. This, of course, is an awesome step in the right direction.
To catapult to the next step, however, will require much more sensitive building design and siting. The days of using the same look on all elevations is coming to a close. To be blunt, we will never achieve net zero energy consumption if we don’t return to the basics of our dwellings’ relationship to the sun, and how to optimize it for resident comfort and maximum resource stewardship.
You’ve all seen how this is accomplished in sophisticate museums, civic buildings, and perhaps even single-family houses—each of which is typically a simple, four-sided affair where the exposure of each wall to our major passive energy source (the sun) is relatively easy to consider and manipulate. When we place repetitive buildings consisting of multiple units on a site, however, the complexity factor expands logarithmically. Will it really be possible to design individual buildings on a large site in such a manner that each is generally responsive to the azimuth?
The answer is a resounding YES. We must, and we will. The reason is profoundly simple—we must use every trick we know to reduce the buildings’ heating and cooling loads PASSIVELY. Even the simplest building energy modeling programs illustrate that it doesn’t make sense to have the same extent of glazing on the north façade as on the east or west. Sure, we have employed window shading devices selectively where to not do so would roast our residents like so many ants under a magnifying glass. Simply stated, this is a case where if a little is good, a lot is even better.
Architects will need to work harder in the design phase so the gas-and-electric powered climate control systems won’t have to. More building design will be necessary, challenging the inherent efficiencies of the same treatment of each exposure, or the same building rolled out on a property with multiple exposures, all oblivious to the constant energy striking the envelope, which, while seasonal, NEVER CHANGES.
Are you ready for a new era of aggressively passive design?
(Daniel Gehman is principal at Thomas Cox Architects. He can be reached at DanielG@tca-arch.com)