In the April 3, 2008 addition of Nature [1](available online only to subscribers), an article entitled “Architects of a Low-Energy Future” indicates that we can do a much better job in building energy-efficient structures. This opportunity is critically important (as discussed in an earlier post [2] regarding architect Ed Mazria of the highly accomplished non-profit Architecture 2030 [3]) because buildings worldwide account for approximately 45% of total energy consumption, more than “all the world’s cars and trucks put together.”
How much better can we design buildings?
The most efficient of the structures are almost completely passive, meaning they require very little, if any, traditional heating or air conditioning. Yet the overall comfort they provide is, if anything, superior to existing buildings. Nor is there necessarily a cost penalty: these ultra-energy-efficient buildings are often no more expensive to build than conventional structures, and they work out far cheaper if energy bills during their occupation are taken into account.
The hurdles to building these energy-efficient structures do not involve engineering challenges or lack of materials. The major impediments to developing energy efficiency in buildings can be found in “our institutional barriers and market failures rather than technical problems.”
Another big problem is that high energy efficiency is too often not on the client’s radar, and architects are geared to simply giving the clients only what the client wants. This is a shame, as the article points out, because “the biggest payoffs will come from new buildings, where ultralow energy can be designed in from the beginning.” If it is not designed in from the beginning, the work of trying to make the building energy-efficient is much more difficult. Retrofitting generally has to rely upon “bolting on energy intensive air conditioning, heating, and artificial lighting.”
Reading this article, I was astounded by how much energy a good building design can save. Take, for instance, heating and cooling. Most people pour lots of energy into their heating and air-conditioning systems. It was eye-opening to learn that most of this cost is not necessary. With high efficiency installation, glazing, and “thermal bridges” to prevent wasteful energy transfers to the outside, high-efficiency buildings show their “impressive gains in negawatts.”
The building can get its heating from the solar gains through glazing as well as through waste heat from appliances and even our bodies.
Another key technique for temperature control and passive houses is that first counterintuitive: simply let fresh air and from the outside. A pump draws fresh air through a grid of pipes several meters underground, where the temperature is relatively constant throughout the year, 10-14 degrees centigrade . . . When this fresh air arrives at the house, its temperature has already been modulated–warmed up or cool down by the ground, depending on the season . . . this system of air base cooling and ventilation not only saves energy by recycling heat, but vastly improves air quality.
Jeff Christian is the head of buildings technology Center at the Oak Ridge national laboratory. His job is to design cheap and energy-efficient homes for low income families. He is convinced that “cheap, low energy houses will take off in United States only if the government steps in: “The financial incentives we need to drive this are not in place.”
Getting highly efficient buildings actually built sounds like another place where the invisible hand needs a hand. [4]
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