In this project, the investigators and their team are studying thin-film Active Building Envelope technologies. Active Building Envelopes (ABE) constitute a novel enclosure technology that integrates photovoltaic and thermoelectric materials. In thin-film ABE systems, a thin-film photovoltaic system is used to power a thin-film thermoelectric system, and both systems are fully integrated into one thin-film surface. When exposed to solar radiation, thin-film ABE systems have the ability to control the magnitude and direction of heat flow across their surface. Such intelligent control is accomplished by controlling the direction of electrical current applied to the thin-film thermoelectric system. This control feature allows for the development of a new class of materials for which the thermal conductivity is no longer determined by the thickness of a material only. Thin-film ABE technologies constitute a new and critical frontier in the area of intelligent heat transfer materials. Promising applications include the development of very thin and transparent thermal coating systems that can be applied to various enclosure materials, such as glazing.
In thin-film ABE systems, solar energy is used directly to control the direction and magnitude of heat transfer across a material. For example, when applied to a glazing system for use in windows, the internal surface of the glass can become cold during the summer and warm during the winter. Hence, the glass itself will have the ability to control the indoor temperature, making conventional air conditioning equipment obsolete. Furthermore, as thin-film ABE technologies are based on solid state materials, they are completely silent and virtually maintenance free. Other promising applications include the development of advanced thermal control system for use in future space missions, and use in advanced packaging materials that require thermal control. An important incentive for developing thin-film ABE systems is that this technology operates entirely on solar energy. Therefore, when used in building applications to control indoor temperature, significant energy savings can be accomplished. This becomes especially relevant considering that a significant portion of the US domestic energy use is used for space conditioning. The successful development of thin-film ABE technology can therefore offer substantial environmental, economic, and strategic benefits to the US. In conjunction with recent advances in the area of nano-technology, and bio-technology, this research will also open the theoretical path towards the development of future ABE systems that operate at the scale of molecules.
