Team Boston Solar Decathlon home with IB Flat Roof
In October 2009, the National Mall in Washington, DC will be turned into a “Solar Village”, where 20 contemporary solar homes from all over US (and one solar home from Germany), will be on display to demonstrated all the latest and greatest in green construction, and renewable energy. This is the Solar Decathlon 2009, a bi-annual event sponsored by US Department of Energy, many colleges and universities as well as private businesses specializing in green buildings.
In 2007 Solar Decathlon, Boston was represented by a Solar Home built by MIT team and many volunteers interested in green technologies. This year it is Boston Architecture College and Tufts University that sponsor the solar home built by Team Boston. Why team Boston? Because many folks that participated in 2007 Solar Decathlon are doing it again.
We and IB Roof Systems (the manufacturer of Cool PVC flat roofing membrane) had our own humble involvement by sponsoring the roof installation on top of this amazing creation of latest architectural designs and green construction technologies. Now, with a new IB 50-mil PVC membrane, this solar home will be completely water-tight and the built in water collection system will provide it with as much H2O as it need. The roof is also very well insulated with over 5 inches if rigid ISO tapered insulation and additional 12 inches of insulation between the rafters. The cool roofing properties of IB Roofs will minimize its cooling needs, and will waterproof the entire building.
About the Team Boston Solar Home:
By definition, a solar decathlon project will use different solar technologies available on the market. Team Boston has created such a design where virtually every solar system will be utilized. There will be a 4.6 KW Solar PV system consisting of 20 SunTech PV panels. There will be a large solar hot water installation using Viessmann Solar Thermal hot water panels and water storage unit. But aside from these common, roof mounted solar systems, there will be a new solar thermal system, that will provide up to 70% of FREE heating to this house. It is a so called “trombe wall”. I’ve discussed it in our previous article about solar thermal mass windows. But this time, the Boston Solar Home will have ne and improves solar thermal windows: these are not the old 2×2′ window blocks. It will be a full size 8×2 wall/window units, covering entire south side of this solar house, to provide it with all the heat it will need in the winter. To avoid overheating in the summer, the roof will overhang the southern side by 3 feet, and an additional retractable awning will roll out to provide the shade for these thermals walls / windows.
The walls of this solar house have 2 inches of ISO insulation on the outside and 6 inches of between studs insulation. In total there will be more than 30-r in the walls. Although this is a stick construction home, it can easily be labeled as super-insulated, and it will have minimal heat loss, while providing more than enough energy to be completely off the greed, and won’t need any outside energy sources for either heating or cooling.
Portable design of this Solar Home:
For the competition purpose, the house has to be transportable, therefore it is designed and built in 3 sections on a portable foundation blocks so that it can be put on that flat-bed trucks and transported to DC, for the competition, and then transported back.
The house is designed to be easily taken apart put back together: All the mechanical components, a bathroom, kitchen, heating and air-conditioning equipment and electrical panel ate located in one part, and special quick connect ports are used when two living sections are connected. Solar PV panels and solar thermal system are installed on removable racking systems that are mounted to the parapet walls on the roof, eliminating any roof penetrations and potential roof leaks. This also allows for easy removal and re-installation of both types of solar systems.
There will be a fold-able / removable deck / patio area with a handicapped access ramp, making this home a perfect choice for comfortable living in the summer and winter, and usable by anyone.
Final thoughts about the solar house:
Since this solar home is still in construction stage and many systems are not installed yet, it is difficult to get a complete picture of how it will perform. Still, this will be a true zero-energy home, and will actually produce a lot of excess electric power to be sent back into the grid. My biggest personal concern about this home is the cost: without having exact information and costs run down, the estimates are around $800,000. This amounts to about $1000 per square foot of living space (a maximum of 800 sq. ft. of living space is one of the guidelines of the Solar Decathlon competition), which is very expensive and is not very practical. However this is just prototype and if it was a mass production home, the actual cost would be a lot less. This cost also includes the transportation to and from competition site in Washington DC, and nominal expenses such as marketing, promotion, creation of the website, etc. So actual construction costs are somewhere about $500,000-600,000.
This is just a firs report on this solar home, and there will be more, as construction goes on. Stay tuned for a complete report on the roof and solar PV system installation as well as overview of the new solar thermal window units.
Useful resources:
http://www.coolflatroof.com/flat-roofing-blog – Learn about the green cool PVC roofing systems, solar roof products and metal roof installation methods.
http://www.mbmcarpentry.com – Green construction and home improvement ins South-Eastern Massachusetts and Rhode Island.
MA Metal Roofing – Flat roofs will not always fit the design of a solar home, and that is where the greenest roofing technology – a Metal Roof – is perfect fit for any sloped roof design.