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Active Solar Blockbed Floor Design Details InspectAPedia®  -     Q&A on use blockbed concrete block radiant heat floor with warm air heat from a sunspace What is the correct pressure drop for a blockbed active solar floor design? Rules of thumb for block storage in solar design - airflow, heat transfer, pressure drop specifications Block duct floor designs in solar applications & radiant heat floor designs Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices

In this first of our series on active and passive solar heating designs, this article discusses the design specifications for blockbed floor designs in radiant heated floor active solar applications. We discuss design rules of thumb for blockbed floor airflow, pressure drop, and solar design. Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. Our page top photograph shows a ceramic tile floor installed in Buenos Aires.

Readers should also see ROCK-BED SOLAR HEAT STORAGE DESIGN for an alternative to block bed solar heat storage, and for supporting heat storage design details see FLOOR, CONCRETE SLAB CHOICES and PASSIVE SOLAR FLOOR TILES, PHASE CHANGE. Also see SLAB INSULATION, PASSIVE SOLAR and other articles at SOLAR ENERGY SYSTEMS. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Active Solar Heating Systems: Blocked Heat Storage System Design

The link to the original Q&A article in PDF form immediately below is followed by an expanded/updated online version of this article.

• Q&A on Blockbed Floor Design Specifications for Radiant Floor in Solar Installations - PDF version, use your browser's back button to return to this page

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

Blockbed Design for Radiant Heated Solar Floors

Question:

In designing a concrete-block radiant heated floor with heat supplied by warm air from a sunspace, how do I determine the correct pressure drop?

Is there an optimum length for an air passage using hollow core concrete blocks? -- Herman Blumen. Eden UT

Answer:

Solar designer Mike Nicklas of Innovative Design Ind., (Raleigh NC) reported the following rules of thumb that work well for concrete block storage of heat in a solar-heated radiant-heat floor.

1. First, size the airflow to exhaust 2-5 cfm (cubic feet per minute) per square foot of sunspace glazing.
2. Then size the blockbed to take 25 to 50 cfm of air through each block core.
   
3. For the best heat transfer from warm air from the sunspace into the concrete block bed of the radiant-heat floor, a maximum core length of 16 feet has been set.

These rules of thumb for radiant heat blockbed floor designs seem to hold true regardless of the sunspace size. The optimum run length is 12-14 feet.

For this length of masonry block duct, the pressure drop is 0.1 inches of water, assuming the standard 8" x 8" x 16" concrete blocks, which have a concrete block core diameter of about 5".

Smaller concrete blocks have a greater pressure drop because the smaller core opening size presents greater resistance to airflow.

For an alternative design approach to storing heat in solar heating designs see ROCK-BED SOLAR HEAT STORAGE DESIGN, and for solar designs that combine greenhouse solar heat gain and trombe wall designs see GREENHOUSE DESIGN for SOLAR HEATING.

For more on radiant slab floors see "Radiant Floors", Solar Age 5/82, and the following articles online:

RADIANT HEAT
RADIANT HEAT Floor Mistakes to Avoid
RADIANT HEAT TEMPERATURES
RADIANT SLAB FLOORING CHOICES
RADIANT SLAB TUBING & FLUID CHOICES

Other articles you'll want to see on passive solar floors, ceilings, and walls, include

• FLOOR, CONCRETE SLAB CHOICES
• SLAB INSULATION, PASSIVE SOLAR
• THERMAL MASS in buildings

The question-and-answer article above, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

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• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

SOLAR ENERGY SYSTEMS
  BLOCKBED RADIANT FLOORS - SOLAR DESIGN
  GREENHOUSE DESIGN for SOLAR HEATING
  GREENHOUSE / SUNSPACE GLARE
  PASSIVE SOLAR DESIGN KEY ELEMENTS
  PASSIVE SOLAR DESIGN METHOD
  PASSIVE SOLAR ENERGY MONITORING
  PASSIVE SOLAR FLOOR TILES, PHASE CHANGE
  PASSIVE SOLAR HEAT PERFORMANCE
  PASSIVE SOLAR HOME, LOW COST
  PASSIVE SOLAR PERFORMANCE PROBE
  PASSIVE SOLAR Roof & Window Overhangs
  PHOTOVOLTAIC POWER SYSTEMS
  POLYCARBONATE GLAZING
  REMOTE ELECTRIC POWER, PHOTOVOLTAIC
  ROCK-BED SOLAR HEAT STORAGE DESIGN
  SLAB INSULATION, PASSIVE SOLAR
  SLATE THERMAL MASS for SOLAR HEAT STORAGE
  SOLAR COLLECTOR AIR or GAS COLLECTION
  SOLAR COLLECTOR EFFICIENCY COMPARISONS
  SOLAR COLLECTOR FILMS
  SOLAR COLLECTOR OUTGASSING
  SOLAR COLLECTOR WOOD HOUSINGS
  SOLAR GAIN CALCULATION
  SOLAR HEATING SYSTEM DESIGNS
  SOLAR HOT WATER HEATERS
  SOLAR HOUSE EVALUATION
  SOLAR MODULE MANUFACTURERS
  SOLAR SHADES & SUNSCREENS
  SOLAR SHADES, LOW-E EFFECTIVENESS
  SOLAR WATER DISINFECTION
  SOLAR HOT WATER HEATERS
  SUNSPACE DESIGN for SOLAR HEATING
  SUNSPACE GLAZING for SUNTANNING
  STORM WINDOW INTERIOR
  STORM WINDOW PLASTIC CHOICES
  STORM WINDOW WEEP HOLES
  SUNGAIN, FILMS, LOW-E GLASS
  SUNSPACE GLAZING for SUNTANNING
  SWIMMING POOL SOLAR HEAT, INDOOR
  SWIMMING POOL SOLAR HEAT, OUTDOOR DIAGNOSIS

THERMAL MASS in buildings
  THERMAL MASS FLOOR SLABS
  THERMAL MASS in UPSTAIRS
  THERMAL MASS WALL DESIGN

• 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.
• Ar-Lite Panelcraft, Inc., 13030 Wayne Rd., Livonia MI 48150
• Colloidal Materials, Inc., PO Box 696, Andover MA 01810
• Pennwalt Corp., King of Prussia, PA 19406
• 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
• The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the InspectAPedia Bookstore
• "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 Exchangers for Solar Water Heating Systems", U.S. DOE describes the types of solar water heater heat exchange methods between the sun and the building's hot water supply
• "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 Maintenance and Repair", U.S. DOE
• "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.
• "Scaling and Corrosion in Solar Water Heating Systems", U.S. DOE
• www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 is the base U.S. DOE website for these articles
• "Active Solar Heating Systems", U.S. Department of Energy, including
• "Radiant Heating Systems" U.S. DOE
• "Absorption Heat Pumps & Coolers", U.S. DOE
• "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 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.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

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