CSIR-NAL Transfers Solar Absorber Coating Tech To Helix Solar

CSIR–National Aerospace Laboratories (CSIR-NAL) has transferred solar absorber coating technology, NALSUN-NG™, to Helix Solar, an emerging clean-tech start-up based in Mysuru, Karnataka. Through the formal agreement signed between the parties on June 23, 2025, CSIR-NAL would transfer NALSUN-NG solar absorber coating technology to Helix Solar, which would be used in flat plate solar water heaters. 

The technology enables domestic manufacturing of flat plate solar water heaters, potentially reducing monthly imports of 5–6 lakh evacuated tube collectors. NALSUN-NG™ is a graphene oxide-based solar selective coating, specifically engineered for photothermal applications such as solar water heaters. The technology was developed entirely in-house by CSIR-NAL. It’s an eco-friendly, water-based coating, and unlike traditional coatings that rely on volatile organic compounds (VOCs) and flammable solvents, NALSUN-NG™ uses only non-toxic, RoHS- and REACH-compliant inorganic materials.

Technology Used By NALSUN-NG

This is the second successful licensing of the NALSUN-NG™ technology following its earlier adoption by an industry partner. This technology has already been commercialized and integrated into solar thermal systems. The repeated interest from the sector indicates the technological maturity and market relevance of this indigenous innovation. Moreover, the growing interest in this technology can likely help to accelerate the deployment of the flat plate solar water heaters. 

Most current commercial coatings use capital-intensive physical vapor deposition (PVD) techniques or contain harmful VOCs. In contrast, NALSUN-NG™ requires minimal investment in infrastructure, has no flammable components, and poses no effluent treatment challenges, making it ideal for local manufacturing and rural deployment.

The coating has undergone testing aligned with ASTM and International Energy Agency (IEA) standards. It is certified by NABL-accredited laboratories. This technology is an intellectual property that is protected under Indian and international patents. With a lifespan exceeding 20 years, NALSUN-NG™ is trademarked and has already been successfully commercialized.