Enhancement of spectral absorption of solar thermal collectors by bulk graphene addition via high-pressure graphite blasting

This work presents the results of construction and testing of a flat plate thermal solar collector with an absorber section that has enhanced radiative properties through the modification of its surface properties. A copper oxide layer is grown on top of the copper absorber by chemically treating it in an ammonia atmosphere. Then, a novel graphene mechanical deposition technique is employed that uses compressed air to deposit few layer graphene on top of the copper oxide substrate. In total, three absorbers are made, one features the copper oxide layer, the second has graphene on top of copper oxide and the third is the reference absorber covered with a black matt paint. The radiative properties of the absorbers are assessed, as well as their thermal efficiencies. The best performance was recorded for the graphene-clad copper oxide collector, with a maximum efficiency of 69.4% compared with an efficiency of around 39.5% for the reference collector.