# Venture Firm Nth Power Names 5 Next-Gen Green Building Materials to Watch

Building materials typically don’t arise as examples of high technology. In the green building sector, energy management systems and building-integrated renewable power generation have drawn much of the attention from tech-oriented innovators, with less activity around green building materials. But the authors of a new report on green building innovation from San Francisco, Calif.-based venture capital firm Nth Power and the Fraunhofer Center for Sustainable Energy Systems see a series of “revolutionary innovations” on the horizon for building materials.

This comes at a time when the global market for green building materials is expected to grow 5 percent a year to reach $571 billion by 2013, up from$455 billion last year, forecasts NexGen Research. And the stimulus package, which includes more than $10 billion in funding to make buildings more energy efficient, should drive demand, at least in the near term, for these technologies. The Fraunhofer Center and Nth Power say these five innovations, all of which are in the “pipeline” (though no specific dates were given), could make structures easier and cheaper to build and more energy efficient. High-Efficiency Insulation Systems: For years, building-product manufacturers have been making windows filled with gas to increase their insulating properties, but only recently have efforts intensified to use similar technology in wall systems, the report said. Some gas-filled panels under development use small vacuum-sealed plastic bags filled with low-conductivity gas and can yield thermal efficiency ratings as high as R-20 per inch, compared with traditional fiberglass installation of about R-3 per inch. But the newer systems still have issues around longevity and high cost. Phase Change Material: These materials are capable of storing and releasing large amounts of energy as they change from solid to liquid. New building products are being engineered, the report authors note, to contain micro-encapsulated phase change materials, or PCMs. This could help stabilize the indoor temperatures in buildings by, say, releasing heat absorbed during the day at night when the outsider air cools down. Conventional concrete and masonry are currently used in this way in some building designs, but newer materials, such as those being developed by Aegis Building Technologies, could be lighter and cheaper and produce the same effect. Reflective Coatings and Nanostructures: Building surfaces, especially roofs, absorb a lot of heat and drive up cooling costs in the summer. New reflective coatings and nanostructures can be used to reduce or promote heat absorption in building surfaces. Energy Seal Coatings, for example, has been working on building better reflective coatings since the mid-1990s. These technologies can be integrated with existing materials to produce more efficient, longer-lasting, self-cleaning systems while still looking the same as conventional products, the report said. Smart Windows: Automated blinds or sunshades can limit the amount of sunlight that passes into a building, but these features restrict outdoor visibility, are expensive and often unreliable, the report said. Smart windows, designed to dynamically change their properties to block sunlight, can reduce cooling demand and prevent glare at the same time. Nth Power and the Fraunhofer Center list two approaches: Electrochromic technologies (being developed by companies including stealthy Soladigm) use electrical voltage to darken or lighten the tint of a window and manage the sunlight that passes through it. The second type, gasochromic technologies, inject hydrogen gas into a sealed cavity, which reacts with a metal layer on the window pane to control solar transmittance. According to Monday’s report, the energy savings from these new windows will depend “strongly on well-tuned control system settings.” Companies that develop better predictive and adaptive algorithms, faster response times and interconnectivity with a building’s automated systems will have an advantage in this space. But the biggest hurdles for widespread use of these windows are high upfront cost and uncertain product lifetime. One company looking to overcome these barriers is Littleton, Colo.-based ITN Energy, which received$4.9 million in DOE funding to develop “roll-to-roll” manufacturing technology for making low-cost elecrochromic windows.

Ventilated Double-Skin Facades: These systems use inner and outer glass walls on a building with a thin cavity between the two. This provides insulation, and heat absorbed within the cavity can be used to warm cooler areas of a building. To be most effective, the system should be coupled with other technologies like active blinds, natural ventilation and automated lights. But without careful planning to integrate these technologies, the report cautions, these systems can actually increase a building’s energy use. Finding ways to simplify component integration, optimize design and improve control algorithms could speed adoption of this technology, according to the researchers.

Photo courtesy of Flickr user Payton Chung