A surge in technology for solar and other forms of renewable energy has prompted ASTM International to revise and reinstate a previously withdrawn ASTM standard, ASTM E903, Test Method for Solar Absorptance, Reflectance and Transmittance of Materials Using Integrating Spheres.
ASTM E903 is now under the jurisdiction of Subcommittee E44.20 on Glass for Solar Applications, part of ASTM International Committee E44 on Solar, Geothermal and Other Alternative Energy Sources. The standard covers the measurement of spectral absorptance, reflectance and transmittance of materials using spectrophotometers equipped with integrating spheres.
‘Since 2003, there has been tremendous growth in solar energy systems technology, along with new developments in materials science related to solar energy, windows technology and thermal energy management films,’ explains Daryl Myers, an ASTM member who is retired after 37 years with the Electricity, Resources and Building Systems Integration Center at the National Renewable Energy Laboratory.
The standard establishes uniform criteria for measurement procedures, equipment and reporting of results with respect to modern measurement equipment, the organization says. ASTM E903 will be used by manufacturers of glass, coatings, films and optical components of solar energy systems elements to assess the reliability, durability and performance of these components.
Properties of interest that can be measured via ASTM E903 include transmittance of glass, absorption coefficients of solar thermal receiver paints and materials, and improvements in collection of photons for photovoltaic systems by use of textured cover glasses.