Concentrating Applications


SOLKOTE HI/SORB-II is an optical coating specifically formulated for solar thermal applications. Its high temperature tolerance, resistance to moisture and UV degradation, and excellent optical qualities make it an ideal, low cost substitute for electro or vacuum deposited selective surfaces. Its high absorptivity and strong adhesion makes it an ideal coating for all concentrating solar absorber surface materials. With a proven history of reliability and longevity, SOLKOTE has powered many of the world’s largest solar thermal manufacturers’ collectors since 1980. Is your collector powered by SOLKOTE?

STG International

STG International parabolic trough concentrating solar collector

SOLKOTE offers the following unique features:

  • Low cost (50 – 75% cheaper than competing selective surfaces)
  • Easy spray application (requiring very low capital investment)
  • Excellent high temperature tolerance (1000°F/538°C)
  • Excellent resistance to UV and moisture degradation
  • Excellent long term durability (does not lose absorptivity over time)
  • Excellent optical characteristics
  • Excellent coating for CSP & CLFR technologies
  • No out-gassing when correctly cured
  • May be used in low to high temperature glazed  & vacuum applications
  • Shipped premixed, ready to apply
  • Excellent shelf life (one year from date of mfg.)
  • Not recommended for exterior or unglazed applications

SOLKOTE HI/SORB-II is the absorber surface of choice for many of the world’s leading solar thermal manufacturers. SOLKOTE can provide superior optical properties to concentrating solar systems for a fraction of the cost of cost of electro or vacuum deposition and is one of the few selective surfaces in the world with a 30+ year history of in-field use. SOLKOTE is an ideal selective surface for concentrating solar thermal systems. Its silicone polymers allow for coating on a wide variety of low e substrates like copper, aluminum, stainless steel, nickel plated surfaces and more, however caution should be used when considering expected temperature regimes; for example copper oxidizes over 400F (205C), which may lead to coating de-lamination. SOLKOTE provides an extremely durable surface on flat panels, with strong UV and moisture resistance and temperature tolerance to 1000F (538C). It will not degrade under severe stagnation temperatures. SOLKOTE can be used in vacuum applications if properly cured.

Areva Solar

Areva Solar compact linear fresnel reflector (CLFR) using solkote on stainless absorber tubes

SOLKOTE is a perfect technology for the solar concentrating startup because it requires minimum capital investment, a simple paint sprayer. It allows for an extremely low cost selective surface that can be applied evenly for smooth, consistent coating on tubular geometries. It is a maintenance free material that will provide stable optics for the life of your collector.

Optical properties are driven by surface preparation, coating thickness and substrate material. SOLKOTE must be properly cured and glazed (under glass) for best results. Please contact us at the factory for assistance and use the form below for pricing inquiries.