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The IR Thermography Laboratory

Berkeley Lab's Infrared Thermography Laboratory (IR Lab) conducts detailed experiments on the thermal performance of windows and other insulated systems. Its facilities have also been used to study a variety of other technologies such as lighting, roofing materials, and photovoltaic tiles. During a typical experiment, a specimen is placed between two environmental chambers that simulate a long, cold winter night. Besides generating informative thermal images, the experiments collect several types of quantitative data with high spatial resolution. These data are useful for understanding subtle details in the thermal performance and for validating computer simulations of heat and fluid flows. Thermography experiments in the IR Lab use an infrared imager to produce qualitative thermal images, or thermograms, that help visually interpret how heat is flowing through the specimen. The infrared thermograms are also processed to extract numerical data to perform quantitative thermography that produces a database of the distribution of surface temperatures on the warm side of various specimens. A traversing system is also used to measure the distribution of air temperatures and velocities near the specimen. The IR Lab houses a machine-tool shop area that supports fabrication efforts. Other types of research, such as nondestructive evaluation, are also conducted in the IR Lab.

Figure 1. Thermograms of hollow (left) and foam-filled (right) vinyl windows, showing higher interior surface temperature and reduced heat loss in the latter.

The IR Lab helps improve the energy efficiency of buildings, appliances, and automobiles by aiding in the development of technologies with high thermal performance and by improving the analysis of complex heat-flow situations. Current areas of interest include improving the edges and frames of windows, validating computer programs that simulate window performance, and analyzing localized surface heat transfer coefficients. Even today's highest-performance windows need improvement because edge heat losses can reduce overall performance by up to a factor of two. Figure 1, an example of hollow and foam-filled vinyl windows, shows that the better-insulated vinyl windows foam-filled windows lose less heat.

Thermograms of photovoltaic roof tiles

Figure 2. Thermograms of photovoltaic roof tiles.

Studies performed by IR Lab researchers have also been used to measure the thermal characteristics of roofing materials. Roof materials that are good reflectors of heat help reduce the need for air conditioning inside homes and small commercial buildings. In Figure 2, thermograms of photovoltaic roof tiles help determine the effect of tile design on solar cell operating temperatures (cooler photovoltaics are more efficient).

— Brent Griffith

For more information, contact:

  • Brent Griffith
  • (510) 486-6061; fax (510) 486-6046

 

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