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 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.

Schematic representation of the miniaturization of the ABE system Image by RPI/Van Dessel

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.

Currently, Van Dessel is collaborating with Achille Messac, professor of mechanical, aerospace, and nuclear engineering (MANE) and a team of students in Rensselaer’s architecture and MANE programs to investigate the potential of ABE systems operating at the micrometer scale. The miniaturized system would function in a similar fashion to the original, but would use thin-film photovoltaic and thin-film thermoelectric materials instead of bulk components. The very fine, transparent material would function as a thermal coating system that could be applied on to various surfaces, much like a glaze. This ease of application would make it possible to seamlessly apply the system to both new and existing building surfaces, rendering conventional air conditioning and heating equipment obsolete, according to Van Dessel.

Read the press release.

Published December 5, 2005