SELECTIVE ABSORBING SURFACE FOR EVACUATED SOLAR COLLECTOR TUBES

The absorptance of AlN-Al(absorbing coating)/Al solar spectrum(0.34 si milar to 1.5 mu m) selective absorbing surface, containing 8-layer AIN -AI composite materials and with distinctive or non-boundaries between the layers, deposited by sputtering technology and heat-treated at 40 0 degrees C(60min) is about 0.95 and its thermal emittance is close to 0.07 similar to 0.08(80 degrees C)But on the condition that the absor ptance is unchanged the thermal emittance dropped to 0.04 for the AlN- Al coating composed of mater volum fractionic 0.42. 0.25 and 0.00 film s (C) 1998 Published by Elsevier Science Ltd. All rights reserved.