Advanced solar selective coatings
Advanced solar selective coatings employ two patent technologies :
(1) double cermet film structure with the highest photothermal efficiency
(2) metal-Aluminum nitride cermet (M-AlN) materials deposited by a novel sputtering technology.
The typical film structure of M-AlN cermet selective surfaces

schematically shown in the figure one

Models	Ф47×150	Ф58×180	Ф58×192	Ф58×210
Weight	1.35±0.12kg	2.29±0.18kg	2.45±0.20kg	2.67±0.22kg
Structure	All glass coaxial double-layer tubes	All glass coaxial double-layer tubes	All glass coaxial double-layer tubes	All glass coaxial double-layer tubes
Outer tube diameter	Ф47±0.7mm	Ф58±0.7mm	Ф58±0.7mm	Ф58±0.7mm
Inner tube diameter	Ф37±0.7mm	Ф47±0.7mm	Ф47±0.7mm	Ф47±0.7mm
Outer Tube thickness	1.6±0.15mm	1.8±0.15mm	1.8±0.15mm	1.8±0.15mm
Inner tube thickness	1.6±0.15mm	1.6±0.15mm	1.6±0.15mm	1.6±0.15mm
Tubes length	1542±4mm	1812±4mm	1932±4mm	2100±4mm
Material of coating	AlN/AIN-SS/Cu	AlN/AIN-SS/CU	AlN/AIN-SS/CU	AlN/AIN-SS/CU
Absorptance	0.94~0.96	0.94~0.96	0.94~0.96	0.94~0.96
Emittance	0.04~0.06	0.04~0.06	0.04~0.06	0.04~0.06
Vacuum	P≤5×10-3pa	P≤5×10-3pa	P≤5×10-3pa	P≤5×10-3pa
Transmittance of Outer Tube	0.91	0.91	0.91	0.91
Stagnation temperature (height)	270~300℃	270~300℃	270~300℃	270~300℃
Heat-loss coefficient	≤0.6w/ m2*℃)	≤0.6 w/ (m2*℃)	≤0.6 w/ (m2*℃)	≤0.6 w/ (m2*℃)
Bearing hailstone ability	hailstone diameterФ25mm	hailstone diameterФ25mm	hailstone diameterФ25mm	hailstone diameterФ25mm
Pressure-endure ability	1MPa	1MPa	1MPa	1MPa