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Title: State-of-the-Art Highly Insulating Window Frames - Research and Market Review

Abstract

This document reports the findings of a market and research review related to state-of-the-art highly insulating window frames. The market review focuses on window frames that satisfy the Passivhaus requirements (window U-value less or equal to 0.8 W/m{sup 2}K ), while other examples are also given in order to show the variety of materials and solutions that may be used for constructing window frames with a low thermal transmittance (U-value). The market search shows that several combinations of materials are used in order to obtain window frames with a low U-value. The most common insulating material seems to be Polyurethane (PUR), which is used together with most of the common structural materials such as wood, aluminum, and PVC. The frame research review also shows examples of window frames developed in order to increase the energy efficiency of the frames and the glazings which the frames are to be used together with. The authors find that two main tracks are used in searching for better solutions. The first one is to minimize the heat losses through the frame itself. The result is that conductive materials are replaced by highly thermal insulating materials and air cavities. The other option is to reducemore » the window frame area to a minimum, which is done by focusing on the net energy gain by the entire window (frame, spacer and glazing). Literature shows that a window with a higher U-value may give a net energy gain to a building that is higher than a window with a smaller U-value. The net energy gain is calculated by subtracting the transmission losses through the window from the solar energy passing through the windows. The net energy gain depends on frame versus glazing area, solar factor, solar irradiance, calculation period and U-value. The frame research review also discusses heat transfer modeling issues related to window frames. Thermal performance increasing measures, surface modeling, and frame cavity modeling are among the topics discussed. The review shows that the current knowledge gives the basis for improving the calculation procedures in the calculation standards. At the same time it is room for improvement within some areas, e.g. to fully understand the natural convection effects inside irregular vertical frame cavities (jambs) and ventilated frame cavities.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Environmental Energy Technologies Division
OSTI Identifier:
941673
Report Number(s):
LBNL-1133E
TRN: US200902%%59
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32; ALUMINIUM; BUILDING MATERIALS; CAVITIES; ENERGY EFFICIENCY; FOCUSING; GLAZING MATERIALS; HEAT LOSSES; HEAT TRANSFER; MARKET; NATURAL CONVECTION; NET ENERGY; POLYURETHANES; RADIANT FLUX DENSITY; SOLAR ENERGY; SPACERS; WINDOW FRAMES; WINDOWS; WOOD

Citation Formats

Gustavsen, Arild, Jelle, Bjorn Petter, Arasteh, Dariush, and Kohler, Christian. State-of-the-Art Highly Insulating Window Frames - Research and Market Review. United States: N. p., 2007. Web. doi:10.2172/941673.
Gustavsen, Arild, Jelle, Bjorn Petter, Arasteh, Dariush, & Kohler, Christian. State-of-the-Art Highly Insulating Window Frames - Research and Market Review. United States. doi:10.2172/941673.
Gustavsen, Arild, Jelle, Bjorn Petter, Arasteh, Dariush, and Kohler, Christian. Mon . "State-of-the-Art Highly Insulating Window Frames - Research and Market Review". United States. doi:10.2172/941673. https://www.osti.gov/servlets/purl/941673.
@article{osti_941673,
title = {State-of-the-Art Highly Insulating Window Frames - Research and Market Review},
author = {Gustavsen, Arild and Jelle, Bjorn Petter and Arasteh, Dariush and Kohler, Christian},
abstractNote = {This document reports the findings of a market and research review related to state-of-the-art highly insulating window frames. The market review focuses on window frames that satisfy the Passivhaus requirements (window U-value less or equal to 0.8 W/m{sup 2}K ), while other examples are also given in order to show the variety of materials and solutions that may be used for constructing window frames with a low thermal transmittance (U-value). The market search shows that several combinations of materials are used in order to obtain window frames with a low U-value. The most common insulating material seems to be Polyurethane (PUR), which is used together with most of the common structural materials such as wood, aluminum, and PVC. The frame research review also shows examples of window frames developed in order to increase the energy efficiency of the frames and the glazings which the frames are to be used together with. The authors find that two main tracks are used in searching for better solutions. The first one is to minimize the heat losses through the frame itself. The result is that conductive materials are replaced by highly thermal insulating materials and air cavities. The other option is to reduce the window frame area to a minimum, which is done by focusing on the net energy gain by the entire window (frame, spacer and glazing). Literature shows that a window with a higher U-value may give a net energy gain to a building that is higher than a window with a smaller U-value. The net energy gain is calculated by subtracting the transmission losses through the window from the solar energy passing through the windows. The net energy gain depends on frame versus glazing area, solar factor, solar irradiance, calculation period and U-value. The frame research review also discusses heat transfer modeling issues related to window frames. Thermal performance increasing measures, surface modeling, and frame cavity modeling are among the topics discussed. The review shows that the current knowledge gives the basis for improving the calculation procedures in the calculation standards. At the same time it is room for improvement within some areas, e.g. to fully understand the natural convection effects inside irregular vertical frame cavities (jambs) and ventilated frame cavities.},
doi = {10.2172/941673},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

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