Experimental study of radiation absorption by microchannels of varying aspect ratios

A linear solar concentrator produces electricity by using a mirror to focus sunlight on a fluid filled tube known as a heat collection element. The fluid inside the element is then used as a heat source for steam generation in a conventional steam turbine power plant. This study examined the effect of adding microstructures to the surface of a heat collection element to improve system efficiency. Four test pieces, one with a smooth surface and three with a microstructured surface were compared experimentally for a given energy input and five different flow rates ranging from 0.84 cm3/s to 2.5 cm3/s. Over the entire range of flow rates the microchannel test piece absorbed no less than 1.29 times the energy of the smooth test piece.