Q&A: combination solar systems involving water well, direct gain, and Trombe wall in one building
How to calculate solar energy savings fraction for passive solar systems
Solar design handbook questions and answers
Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices
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This article discusses the Passive Solar Design Handbook leaves some passive solar evaluation (solar energy savings fraction) questions that are answered by an expert. Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. Our page top photo shows windows admitting morning solar gain in a nearly-balanced-energy passive solar home in San Miguel de Allende, Guanajuato, Mexico.
Readers who need to understand the basics of how passive solar heating systems work should see PASSIVE SOLAR DESIGN KEY ELEMENTS. Readers concerned with accurate calculation of the "percent solar" and similar energy savings assessments should see PASSIVE SOLAR HEAT PERFORMANCE. Readers should also see SOLAR HOUSE EVALUATION. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
The question-and-answer article about passive solar design for combination systems that combine a water well source, direct solar gain, and a Trombe wall, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.
The U.S. DOE illustration (left) identifies the five elements of passive solar design: aperature, control, distribution, absorber, and thermal mass (see PASSIVE SOLAR DESIGN KEY ELEMENTS for details). The question below discusses use of a Trombe wall for thermal mass.
Question: I have questions concerning the Passive Solar Design Handbook.
For a house with a combination solar system, that is, combining a water well, direct solar gain, and a Trombe wall in one building, how does one go about finding the solar savings fraction?
Do the calculations take into account internal gains? -- Richard Glaser, Glenwood Springs CO
Answer:
If the passive solar designed building has more than one type of energy system, divide the building load coefficient by the combined areas of all the passive solar energy system types to get a single Load Collector Ratio (LCR).
Using that LCR, determine the solar savings fraction for each alternative energy system type. This amounts to assuming that the entire solar wall is first one type, then the next, and so forth.
The final solar savings fraction is the average of each fraction weighted according to the percentage each solar energy system represents in the combined solar collector area.
The solar fraction calculation procedure is explained well enough in Volume III of the Passive Solar Design Handbook.
The LCR method of assessing the solar savings fraction does not take into account heat gains from people, lights, or appliances. For a closer look at the passive solar design method and for the answers to many other questions you may have about it, Solar Age Magazine published a series of articles beginning in May 1983.
List of Passive Solar Design Key Reference Books including Online Texts
The first three passive solar design handbook links below are to free, online documents.
Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, 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_v1.pdf
Passive Solar Design Handbook Volume II, 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, 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
"Passive Solar Home Design", 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.
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
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Additional technical contributors & reference sources for this article are listed below.
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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."
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.
Excerpts with updates and annotations expanding the original Best Practices Guide text can be found in the online review and book summary at BEST CONSTRUCTION PRACTICES GUIDE and also at DECK & PORCH CONSTRUCTION, at INDOOR AIR QUALITY IMPROVEMENT GUIDE, and in other articles found at InspectAPedia.com such as HOUSEWRAP AIR & VAPOR BARRIERS, SOUND CONTROL in buildings, and other topics.
Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, 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_v1.pdf
Passive Solar Design Handbook Volume II, 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, 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
"Passive Solar Home Design", 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", 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", 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", 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" 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" U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy inthe 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.
"Basic Hydronic underfloor - thermal storage 8 to 14 hours of control", this sketch, provided by OPTCO, is not a conventional radiant heating system design - and you'll see that the designer places the tubing too deep for efficient radiant heat delivery to the occupied space. However this design is intended for heat storage, such as in a solar heat storage system. See PASSIVE SOLAR DESIGN METHOD for more information. See Radiant Heat Floor Mistakes to Avoid for a discussion of effective radiant heating floor slab design.
Passive Solar Home Design - U.S. DOE Suggestions http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10250
Passive Solar Window Design - U.S. DOE http://www.energysavers.gov/your_home/windows_doors_skylights/index.cfm/mytopic=13360
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