It's autumn, and the annual Solar Decathlon is underway (through October 2nd). After being highlighted on the National Mall for several years, this year, the contestants are instead located in West Potomac Park, near the Roosevelt and Jefferson Memorials in Washington DC, maybe less publicly front-and-center, but no less interesting and engaging than in previous years.
The Solar Decathlon teams compete with small, energy efficient model homes that address five key criteria:
Affordable, attractive, and easy to live in
Maintains comfortable and healthy indoor environmental conditions
Supplies energy to household appliances for cooking, cleaning, and entertainment
Provides adequate hot water
Produces as much or more energy than it consumes
This year's contestants include teams from 20 universities from across the US, as well as international teams from Belgium, Canada, China, and New Zealand.
The projects are judged on ten different contests throughout the week. Public voting for the People's Choice Award runs through Sunday, when the final winner will be announced.
Link: Gallery of Houses
Last month, Google announced that it would no longer use any of the construction materials found on the Living Building Challenge's "red list." For a company that is opening new office space at a rate of 40,000 square feet (about 3,700 square meters) per week, that's a lot of construction activity, and a lot of materials that are no longer being used for those projects. It's also a leadership role from a company that wants to be environmentally positive.
The red list (as opposed to the green list) is a list of construction materials that include components made from products such as mercury, asbestos, PVC, formaldehyde and lead. In most cases, these materials are poor for the indoor air quality of the spaces where they are installed. But, even if the final form is relatively inert, the production of these materials also has a large environmental toll due to the extraction of materials used to produce them and from the processing of raw materials to make the finished products.
The Living Building Challenge goes beyond LEED and other green building programs with a standard for creating buildings that are restorative and balanced, rather than being merely "less bad" than typical construction. The red list is found in the Materials section of the Living Building Challenge 2.0 guidebook (pdf).
Like LEED itself, Google's size makes this a decision that will have ramifications throughout the construction industry. Manufacturers who use red list materials in their products will see sales declines not only from Google, but from other companies who will follow Google's lead in this.
The Building Green blog has a wonderful followup that talks not only about these rules, but offers a wider approach to considering appropriate building materials from an environmental perspective.
link: International Living Future Institute
via: friends on Twitter
Is sprawl really so terrible? Of course we are trying to make greener buildings, and many think that efficiency improvements in buildings are the most important part of the solution. But the distance a home is from facilities, services and workplaces is a significant factor in the amount of energy that a home uses.
As the old real estate maxim says, location matters! In fact, the energy needed for transportation can be a bigger portion of the total energy used than the amount used for the house itself.
In conventional suburban development, an average American home uses 108 million BTUs (British Thermal Units--a measure of energy consumption) per year for operation (heating, cooling, lighting, etc.). But that same house uses 132 million BTUs per year in transportation energy use--for a total of 240 million BTU/year. In other words, for that average home, 55% of its total energy use is for transportation, and 45% is for operations.
A very green and energy efficient building can be more than undone by locating that building in a remote area. Even a net-zero energy house can be more of a drain on energy infrastructure if it is remotely located. Furthermore, the amount of energy and effort needed to extend infrastructure (roads, sewer and water lines, electricity and gas lines, etc.) is also an enormous drain on resources and materials.
Recently, the same complaint has been raised with the planned relocation of the EPA's Regional Headquarters in Kansas City KS, which is being moved from the downtown to a more isolated, suburban location, where transport emissions are expected to be 3 times as much as for the previous location.
Buildings need to be greener, but paying attention to the larger systems is also crucial in making meaningful change needed to get to a more energy efficient future.
image: CC BY-SA 3.0 by SimonP/Wikimedia
Production is beginning for a new window coating that automatically adjusts to control solar gain through windows. Raven Windows, made by Denver-based RavenBrick, are made with a special nanomaterial coating which makes the windows responsive to outdoor temperature. The Raven Windows act as "an intelligent window filter that automatically blocks solar heat when the outside temperature is too hot, while delivering solar heat inside when the outside temperature is cold."
The Raven Window material is a thermo-reflective coating that is applied to the inside surface of the outer pane of glass in a double-glazed window assembly. The material is somewhat like glasses that darken when you step outside into brighter conditions. Although darker, the material is more thermally reflective, so that heat is kept out of the building during hotter times of year, but is transparent, and lets heat and light through when the temperature is colder. Better yet, unlike some other technologies, the transformation is automatic, and requires no electricity or controls.
With Raven Windows, the most reflective state of the glass has a solar heat gain coefficient (SHGC) as low as 0.03, meaning that only 3% of the solar energy passes through the window, which helps cut down the need for air conditioning, but those windows can also adjust during cold weather to allow as much as an SHGC of 0.35.
Like low-E windows, this is a coating applied to one surface of the glass in a double pane window, although the performance of this material is like low-E on steroids. However, "because smart windows and low-E save energy by completely different mechanisms, their effects are complementary and thus their savings can be added together." It is possible to have windows that have the Raven Windows coating, as well as having low-E.
The company's information suggests a retail cost of $25 per square foot for the material and assumes that payback can be achieved within 5-8 years with these windows. One of the first installations of these windows is for executive offices in the new National Renewable Energy Laboratory (NREL) in Colorado.