Researchers at the Technological Institute of the Lagoon in Mexico have developed a superconducting coating which they say increases the efficiency of solar water heaters by up to 70%.

The coating material is a type of paint, classified as an “ink” because of its quick-setting property, that is built up in several layers. The first layer contains magnetic titanium nanoparticles that trap the heat, the layer above that contains tungsten nano salt adhered with polyvinyl alcohol and the top layer is copper, which is burnished to blacken it.

When a conventional pipe, without the coating, was exposed to the sun, it reached a temperature of 40ºC; a similar pipe with the coating reached 70ºC. When implemented in some houses, water flowing in coated pipes for five metres reached a temperature of 68ºC almost instantly.

The superconducting ink, which is currently being patented, is expected to sell for about $US40 a litre, which means that painting all of the solar water piping in a standard house should only cost about $US10.