After building a very efficient building in Boulder, Colorado, the NERL is building an extension that is 17 % more efficient. How ? By looking at changes in available technology in the last year that can bring energy improvements.
One area for change was the windows. Those in Phase 1 are very efficient but still those on the southern exposure were cold ... changes made for Phase 2 included making them slightly smaller and increasing the thermal break to slow air infiltration that can cause temperature changes. When these savings are multiplied over 600 windows the energy efficiency is significant.
Improvements were made in the Phase 2 thermal storage system ... they found they could simplify the design ... instead of " ... interlaced structural concrete grade beams for thermal transfer .... " ... there just now just a " ....a large open concrete crawl space."
Lastly each occupant is put on an energy diet of 55 watts / workstation. This goes a long way to keeping electricxity bills under control.
Follow this LINK and at the bottom of the page are details on other technologies used in the building.
Via: National Renewable Energy Laboratory LINK