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Increased solar energy and daylight utilisation using anti-reflective coatings in energy-efficient windows

Rosencrantz, Tobias LU ; Bülow-Hübe, Helena LU ; Karlsson, Björn LU and Roos, A (2005) In Solar Energy Materials and Solar Cells 89(2-3). p.249-260
Abstract
Glass with low-a coatings based on SnO2 (usually referred to as hard coatings) provides a cost-effective replacement of one of the panes in ordinary double-pane windows. It considerably improves the energy efficiency of the window and at the same time preserves the appearance of,old hand-crafted windows. Adding a low refractive index anti-reflective (AR) coating on both sides of the low-a coated pane in such a double-glazed window makes it possible to achieve high light and solar transmittance, while the U-value remains unaffected. In this study the influence on the daylight factor, solar factor and annual heating demand when AR-coated low-a glass is used instead of normal low-a glass and ordinary clear glass has been investigated for a... (More)
Glass with low-a coatings based on SnO2 (usually referred to as hard coatings) provides a cost-effective replacement of one of the panes in ordinary double-pane windows. It considerably improves the energy efficiency of the window and at the same time preserves the appearance of,old hand-crafted windows. Adding a low refractive index anti-reflective (AR) coating on both sides of the low-a coated pane in such a double-glazed window makes it possible to achieve high light and solar transmittance, while the U-value remains unaffected. In this study the influence on the daylight factor, solar factor and annual heating demand when AR-coated low-a glass is used instead of normal low-a glass and ordinary clear glass has been investigated for a typical multi-family dwelling in Scandinavia using energy and daylight simulation. For a double-glazed window with one low-a hard coating, light transmittance was found to increase by as much as 15 percentage points, from 74 to 89% transmittance, if both panes were AR-treated, while the emissivity of the low-a coated pane was virtually unaffected. Compared to clear double glazing, the visual transmittance was increased by 7 percentage points. The simulations show that the monthly average solar factor (g-value) increased by 7 percentage points compared to the low-a double-glazed window without AR-coatings. The annual heating demand decreased by 4% due to the higher solar transmittance of the window. The AR-coating increased the daylight factor by 21% according to the simulation. The study has shown that the main benefit of using AR coatings in a low-a window is the improvement of visual transmittance and the resulting increase in the daylight factor. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
energy simulations, anti-reflective coatings, low-a coatings, energy-efficient windows, daylighting
in
Solar Energy Materials and Solar Cells
volume
89
issue
2-3
pages
249 - 260
publisher
Elsevier
external identifiers
  • wos:000232363100014
  • scopus:24944468768
ISSN
0927-0248
DOI
10.1016/j.solmat.2004.12.007
language
English
LU publication?
yes
id
ba62a4d2-ab58-4bf5-9713-0847456e2d98 (old id 220521)
date added to LUP
2007-08-15 14:48:35
date last changed
2017-10-29 04:25:52
@article{ba62a4d2-ab58-4bf5-9713-0847456e2d98,
  abstract     = {Glass with low-a coatings based on SnO2 (usually referred to as hard coatings) provides a cost-effective replacement of one of the panes in ordinary double-pane windows. It considerably improves the energy efficiency of the window and at the same time preserves the appearance of,old hand-crafted windows. Adding a low refractive index anti-reflective (AR) coating on both sides of the low-a coated pane in such a double-glazed window makes it possible to achieve high light and solar transmittance, while the U-value remains unaffected. In this study the influence on the daylight factor, solar factor and annual heating demand when AR-coated low-a glass is used instead of normal low-a glass and ordinary clear glass has been investigated for a typical multi-family dwelling in Scandinavia using energy and daylight simulation. For a double-glazed window with one low-a hard coating, light transmittance was found to increase by as much as 15 percentage points, from 74 to 89% transmittance, if both panes were AR-treated, while the emissivity of the low-a coated pane was virtually unaffected. Compared to clear double glazing, the visual transmittance was increased by 7 percentage points. The simulations show that the monthly average solar factor (g-value) increased by 7 percentage points compared to the low-a double-glazed window without AR-coatings. The annual heating demand decreased by 4% due to the higher solar transmittance of the window. The AR-coating increased the daylight factor by 21% according to the simulation. The study has shown that the main benefit of using AR coatings in a low-a window is the improvement of visual transmittance and the resulting increase in the daylight factor.},
  author       = {Rosencrantz, Tobias and Bülow-Hübe, Helena and Karlsson, Björn and Roos, A},
  issn         = {0927-0248},
  keyword      = {energy simulations,anti-reflective coatings,low-a coatings,energy-efficient windows,daylighting},
  language     = {eng},
  number       = {2-3},
  pages        = {249--260},
  publisher    = {Elsevier},
  series       = {Solar Energy Materials and Solar Cells},
  title        = {Increased solar energy and daylight utilisation using anti-reflective coatings in energy-efficient windows},
  url          = {http://dx.doi.org/10.1016/j.solmat.2004.12.007},
  volume       = {89},
  year         = {2005},
}