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| Rensselaer researcher awarded NSF grant to study solar-powered heating and cooling systems Imagine heat radiating from the walls of your home on a cold winter night, or the glass in your home’s windows emitting cool temperatures on a scorching summer afternoon. Now imagine these systems operating on an endless supply of affordable energy – the sun. Three years ago a team of Rensselaer Polytechnic Institute researchers began developing an “intelligent” heating and cooling system that made these seemingly too-good-to-be-true scenarios a possibility. Today the same team is exploring the likelihood of increasing the system’s efficiency and adaptability by reducing it to the micrometer scale. A $300, 000, three-year grant from the National Science Foundation (NSF) will fund the research. Developed by Steven Van Dessel, assistant professor of architecture at Rensselaer, the patented Active Building Envelope (ABE) system uses a photovoltaic (PV) system to collect and convert sunlight into electricity. That power is then delivered to a series of thermoelectric (TE) heat-pumps that are integrated into a building envelope (the walls, windows, and roof). Depending on the direction of the electric current supplied to the TE heat-pump system, the sun’s energy can actively be used to make the inside space warmer or cooler. An energy storage mechanism is also integrated to collect extra energy for use when little or no sunlight is available. The original ABE system uses solar-panels placed on the outside walls or roof of a building. TE heat-pumps approximately one square inch in size are dispersed throughout the building’s envelope. Since this system is made up of bulk materials, its implementation can be costly and impractical. Additionally, the ABE system can only be applied to new construction projects, as the TE devices need to be placed inside the building’s walls, windows, and roof. Van Dessel notes that the creation of an ABE system on the micrometer scale gives way to a new class of materials whose thermal conductivity would no longer be determined by thickness alone. Instead, these materials would interact with their environment to direct and control the flow of energy. He says that, in theory, future ABE systems operating at such a small scale will likely outperform the bulk systems both in cost and efficiency. A self-heating and cooling prototype of the original ABE system resides on the roof of the Student Union at Rensselaer Polytechnic Institute. The new NSF grant will allow for the design and optimization of a prototype of the system on the micrometer scale. In conjunction with recent advances in the area of nanotechnology and biotechnology, this research may also open the theoretical path toward the development of future ABE materials that operate at the scale of molecules, according to Van Dessel. write your comments about the article :: © 2005 Construction News :: home page |