Solar Power Your Garden Dome

How to harness the power of the sun - Use the suns radiant solar energy to heat your dome

Passive Solar Collectors
 
Winter observations from my own Garden Dome 2 that I use as a workable demonstration dome.Inside the dome there's no wind, circulation must be created when the windows are closed. I use the ceiling fan and an excersize bike that has a fan incorporated. I have only ornamental plants of many types, but the carbon dioxide I put out is important to them. It can be very windy outside but calm inside the dome. There's no wind chill factor. If it is 30 and windy outside and snow on the ground, it's 50 inside the dome on a cloudy morning and that's without using the small electric heater. I'm not using the foam insulation, only super poly and my dome is 98% sealed from outside air flow. We had a "mild" winter.
Some pre-engineering of you dome foundation can bring more passive solar heat by using the ground as the solar collector. Here are some ideas of how to do this:

1. Where your dome floor will be dig down about 2 feet. Here you will insulate from the ground up. Put in hard foam board insulation right on the dirt.

2. Tubes below your dome floor will bring the heat collected in the soil into the dome with a circulation fan. Array these tubes strategically spaced on top of the foam insulation. Connected pvc tubes will work well and support the weight of the dirt on them. A blower will circulate the warm air from the conducting tubes into the dome. Your insulated dirt floor makes an excellent solar collector. And you can still grow plants right in the soil without interference. Plants will do well with a warmer ground temperature. Your growing medium/soil can be replaced conveniently as necessary.

Below your dome frame base perimeter, a cinderblock retainer wall can be placed in the ground when you are excavating for placement of the foam insulation and tubes. This will also allow you to insulate the below ground block wall with foam board insulation.

3. Fill the hole back up with the excavated soil. This is your solar collector so you might plan on where no shadows are likely to be.


Some more ideas about using your Garden Dome for growing
  1. Retain heat in winter with insulating techniques and solar collectors
  2. Ventilate in summer with windows and fans. 
  3. Use thermometer to regulate temperatures Shade Thermometers, place away from direct sunlight for most accurate readings
  4. Store water for heat collectors in black containers; flat black paint may be used
  5. Clear jugs may be used; add black paint to the water to make it opaque.
  6. Situate water heat collectors next to north side foam board insulation panels to avoid blocking light on plants
  7. Use weather stripping at doors and windows and rubber sealant to minimize air infiltration
  8. Grow plants/vegetables suitable for the season and temperature
  9. Wind, clouds, sun, growing zone and other factors determine growing invironment-dome air and soil temperature
  10. In winter heat the water in the drums (or one that is centrally located) with a submersable heater 800 - 1000 watt; or space heater near the drums
  11. Use shade cloth during summer to reduce heat; it works best installed on the outside
  12. Use windows with screens, for cross ventilation
  13. Use an exhaust fan
  14. Monitor temperatures more closely in Spring and Autumn when temperature variations may be greater
  15. A thermal actuated automatic window opener works well
  16. Clean the covering once a year. Use biodegradable detergent
  17. Use double layers of film, and silver backed foam board for insulation.
  18. Make removeable triangle panels that are covered with the horticultural film such as our Super Poly. These can be installed in winter for heat retension and removed in summer. Or attach shade cloth to reduce heat in summer. 1" x 2" wood will make a good frame for the removeable triangles. 

Resources:
  1. Sunset- Garden and Patio Building Book (by Sunset Books and Magazine Copyright 1969). Old but usefull, lots of good illustrations.
  2. Growing Solar Food In Greenhouses (by Delores Wolfe, Copyright 1981, Doubleday & Company, Inc., ISBN 0-385-17603-1) "A month-by-month guide to raising vegetables, fruits, and herbs under glass" 1st Edition, 192 pages.
  3. How to Build and Use Greenhouses (by Ortho Books, Copyright 1978, ISBN 0-917102-74-6) Lots of nice color photos, charts and drawings; 95 pages.
  4. The Complete Greenhouse Book (by Peter Clegg & Derry Watkins, Copyright 1978, Garden Way Publishing, ISBN0-88266-142-6) "Building and Using Greenhouses from Coldframes to Solar Structures" More thorough and technical, 280 pages.
  5. The Big Book of Gardening Skills (Copyright 1993, by the editors of Garden Way Publishing, Storey Communications Inc. ISBN 0-8826-796-3) Good book about gardeing in general with one chapter dedicated to greenhouses. 346 pages
  6. Add-On Greenhouses and Sunspaces (by Andew M. Shapiro, Copyright 1985, Rodale Press, ISBN 0-87857-507-3) "Planning, Design, Construction" Very thorough, 355 pages. Mostly pertains to adding to an existing structure.
  7. Greenhouses, Cloches and Frames (by Peter McHoy, Copyright 1984 Blandford Press UK, ISBN 0-7137-1244-9) All aspects of flower and vegetable greenhouse gardening 128 pages w/ color photos
  8. Building a Solar Heated Pit Greenhouse (by Greg Stone, Garden Way Publishing Bulletin A-37, Copyright 1980) 28 page booklet with plans to build a partially sunken greenhouse that uses the earth and sun for heating.
  9. Building and Using a Solar Heated Geodesic Greenhouse (John Fontanella and Alvis Heller, Garden Way Publishing,  1979) Very informative but the dome building technique is difficult and primitive.
On the World Wide Web:

Solar Links from Sierra

Florida Solar Energy Center

Research in Environmental Architecture (good article on solar greenhouse by architect Raold Gunderson)

Garden Web - Greenhouses and Structures Forum


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