This article discusses the effectiveness of Pella's Low-E Type E solar sun shades for passive solar heating in buildings.
Avoiding unwanted night-time heat loss through windows. Effect of night-time insulation on day-time passive solar gain. Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices.
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Effectiveness of Pella Windows with Type-E Slim Shades for Passive Solar Heating in buildings
Our page top photograph shows an older but very effective solution to solar sunshading installed on an apartment building Buenos Aires, Argentina. (These solar shades are not a Pella product).
These hinged solar screens can be latched and opened or shut as a hinged-vertical sunscreen (photo left side) or as an awning-type sunscreen (photo right side). As we show below, this system also permits individual sections of the louvered screen to be open or shut from indoors.
The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
What is the effectiveness of Type-E Solar Slimshades?
Question:
Please evaluate the effectiveness of Pella windows with Type-E Slimshades for passive solar heating. - Jim Chambers, Sunbuilders, Inc., Ft. Wayne IN
Answer:
With the solar shades closed, Pella gives the window an R-value of R-4.35.
This window R-value compares favorably with double-glazing at R-2 and triple glazed windows at R-3.
Although this is lower than the R-values claimed for many night insulation systems, there is no problem with loose edge seals - often a weak point with movable insulation. As with any night insulation over windows, the shade must be used to be effective.
Slimshades have the advantage of being easy to operate.
How about the blocking of solar gain, not just night time heat loss where solar shades are used?
Even when fully open, the low-e solar shades intercept and reflect some sunlight that you are trying to capture for passive solar heating (passive solar gain) in the building. And unfortunately, no one seemed to know (in the 1980's) just what the shading effect is.
Glenn Chafee, director of R&D at Pella Windows said in a 1985 interview that there are so many variables involved that the company had not tried to measure the shading.
Several other research centers around the U.S. echoed this view, though one expert ventured an estimate of 50-percent reduction.
This reduction would make the solar transmission of windows equipped with these shades roughly equal to that of low-e double glazing.
Between-the-glass shades offer convenient night insulation and summer shading, but so far, an unknown amount of shading.
The question-and-answer article about the use of solar shades or solar blinds and blocking unwanted heat gain from sunlight in buildings, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
The link to the original Q&A article in PDF form immediately below is preceded by an expanded/updated online version of this article.
Q&A on Pella Type-E Slim-Shade Solar Shades - effectiveness of these solar shades to control building heat gain - PDF version, use your browser's back button to return to this page
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Citations & References
In addition to any citations in the article above, a full list is available on request.
Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years.
ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: info@buildingadvisor.com Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
Solar Sun Screens, Shades, Solar Sunscreen Fabrics - Suppliers
Levolor Lorentzen, 1280 Wall St. West, Lyndhurst NJ 07071 - solar screens and sunshades - woven polyester screening
Moore Co., Marceline MO 64568 - solar shades and sunscreens, commercial products
Pfifer Wire Products, sells a variety of screening products including both exterior sun control screening and interior sun control screen products - PHIFER Incorporated
P.O. Box 1700,
Tuscaloosa, Alabama, 35403-1700, USA - 205 -345-2120 - solar screens and sunshades - woven polyester screening - info@phifer.com
Quality Solar Screen Co. distributes Pfifer solar screening fabrics and other related products
PASSIVE SOLAR DESIGN HANDBOOK VOLUME I [PDF], the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force
PASSIVE SOLAR DESIGN HANDBOOK VOLUME II [PDF], the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
PASSIVE SOLAR HANDBOOK VOLUME III [PDF], the Passive Solar Handbook Programming Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v3.pdf
The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083
"PASSIVE SOLAR HOME DESIGN [PDF] ", U.S. Department of Energy, describes using a home's windows, walls, and floors to collect and store solar energy for winter heating and also rejecting solar heat in warm weather.
SOLAR WATER HEATERS [PDF] , U.S. Department of Energy article on solar domestic water heaters to generate domestic hot water in buildings, explains how solar water heaters work. Solar heat for swimming pools is also discussed.
HEAT-TRANSFER FLUIDS for SOLAR WATER HEATING SYSTEMS [PDF] , U.S. DOE, describes the types of fluids selected to transfer heat between the solar collector and the hot water in storage tanks in a building. These include air, water, water with glycol antifreeze mixtures (needed when using solar hot water systems in freezing climates), hydrocarbon oils, and refrigerants or silicones for heat transfer.
SOLAR WATER HEATING SYSTEM FREEZE PROTECTION [PDF] , U.S. DOE,using antifreeze mixture in solar water heaters (or other freeze-resistant heat transfer fluids), as well as piping to permit draining the solar collector and piping system.
SOLAR AIR HEATING [PDF] U.S. DOE also referred to as "Ventilation Preheating" in which solar systems use air for absorbing and transferring solar energy or heat to a building
SOLAR LIQUID HEATING [PDF] U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy in the form of heat for transfer into a building for space heating or hot water heating. The term "solar liquid" is used for accuracy, rather than "solar water" because the water may contain an antifreeze or other chemicals.
Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.