Optimization of coatings for flat plate solar collectors: Phase II. Progress report, 28 June--31 December 1976

Technical Report · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7212096

Lin, R J.H.

Optical coatings that would enhance the economic feasibility of flat plate solar collectors were investigated. Etched and dip-coated antireflection coatings and selective absorbing plated and paint coatings that are low cost, and optically efficient coatings were investigated. The best coatings previously identified in Phase I of the coating program were further optimized. A selective paint coating, applied by dip coating, has been developed with solar absorptance (..cap alpha..) of 0.92 and room temperature emittance (epsilon) of 0.13, an improvement from the previous ..cap alpha.. of 0.90 and epsilon of 0.30. The improvement was made through the optimization of coating thickness, pigment volume concentration, and pigment particle size. The coating cost (materials and fabrication) was estimated at less than 5 cents/ft/sup 2/, a factor of at least 10 lower than the selective plated coatings investigated. Black chrome has been shown to endure at least 30 days in an accelerated humidity test with no degradation. This compared to a complete removal of double layer black nickel coatings after 4 days in the same test. The black chrome coating life was estimated to be greater than 20 years. The use of surface roughening to improve the optical properties of black chrome resulted in a sample with ..cap alpha.. = 0.96 and epsilon (100/sup 0/C) = 0.11. Environmental tests of selected solar coatings using mini-collectors have begun for a correlation study for accelerated and outdoor humidity testing and life estimations. Antireflection coatings on glass using low refractive index Teflon FEP resulted in a transmittance increase of about 4.5% over the 0.35 ..mu..m to 0.75 ..mu..m region. Studies on the chemistry of glass etching for better process control have been initiated.

• Research Organization: Honeywell, Inc., Minneapolis, MN (USA). Systems and Research Center
• OSTI ID: 7212096
• Report Number(s): COO-2930-4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
141000* -- Solar Collectors & Concentrators
ABSORPTIVITY
ANTIREFLECTION COATINGS
BINDERS
CHROMIUM
COATINGS
COST
DEPOSITION
DIMENSIONS
DIP COATING
ELEMENTS
EMISSIVITY
FLAT PLATE COLLECTORS
FLUORINATED ALIPHATIC HYDROCARBONS
GLASS
HALOGENATED ALIPHATIC HYDROCARBONS
METALS
NICKEL
OPTICAL PROPERTIES
OPTIMIZATION
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
PAINTS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHYSICAL PROPERTIES
PIGMENTS
PLASTICS
POLYETHYLENES
POLYMERS
POLYOLEFINS
POLYTETRAFLUOROETHYLENE
RESEARCH PROGRAMS
SOLAR COLLECTORS
SPECTRALLY SELECTIVE SURFACES
SURFACE COATING
SURFACE PROPERTIES
SURFACES
TEFLON
TESTING
THICKNESS
TRANSITION ELEMENTS
WEATHERING