Development of inexpensive, simple and environment-friendly solar selective absorber using copper nanoparticle

Abstract

Abstract Concentrating solar power is the most challenging and expensive yet highly efficient source of thermal energy from solar power. This is mainly due to the intermittency of the sun rays and expensive materials used to harness its energy. One of the main components adding to the cost is the solar selective absorber materials which are simply put spectrally selective coatings on a receiver system to capture maximum heat from the sun. These materials add to a large extent to the efficiency of converting the sun’s energy to thermal energy and in turn electricity. An ideal solar selective absorber possesses the property of absorbing maximum radiations in the solar spectrum and emit minimum in the thermal energy spectrum. In the current study, an inexpensive, simple and environment-friendly solar selective absorber is fabricated by a galvanic displacement reaction of copper nanoparticles on galvanised metal substrates. These copper nanoparticles have high absorptivity (0.8–0.9) by virtue of plasmon resonance property. The emissivity is low due to the highly reflective metal substrate. By varying size of the copper nanoparticles from 100 nm to 2 μm emissivity and absorptivity can be varied. However, achieving low emissivity and high absorptivity requires some optimising. The size depends on the concentration of precursor solution and immersion time of substrate. One of the remedies for controlling the deposition rate to tune the nanoparticle size and microstructure of deposited copper nanoparticle is by addition of a deposition inhibitor (e.g. Polyethylene glycol).