[permaculture] Re: Greenhouse design for southern climates
skywatcheraz at earthlink.net
Tue Dec 30 23:10:39 EST 2003
Marilyn and Neal,
Thanks for your ideas. I have seen large drums of water used in
greenhouses before but have never heard of using a hologram to filter
out infrared rays. Can you refer me to a website for more information?
CHINAGRVE at aol.com wrote:
> I live in New Mexico and 50 gallon drums of water in the greenhouse
work great to keep the temp even. They heat in the > winter and cool
in the summer.
> Marilyn Conway
CAVM at aol.com wrote:
> For your brief heating needs a conventional greenhouses of all glass
> or plastic can be heated by a variety of means including natural gas
> and propane but also by used motor oil furnaces and even biomass
> combustion. Used motor oil has about 200,000 BTU per gallon. Propane
> has about 85,000 BTU per gallon for a greater cost than used motor
> oil. Of course, even solar heating is an option.
> As you say, in your area though the major concern is keeping the
> greenhouse from overheating in the summer. While the Sunny John
> system of subsoil air flows to keep temperatures down has many
> applications it is not suitable in all cases. In some situations the
> cooling of the water bath in a hydroponics greenhouse may be
> sufficient with adequate ventilation. Lettuce for example responds
> well to cooling water to fight pythium root rot.
> The major opportunity for your situation though is to screen out the
> infrared rays of the sun yet letting in the white light. This can be
> done with a hologram on the glass of the greenhouse. Holograms are
> very adaptable and very inexpensive. The light of the sun needed for
> the plants will enter but the heat producing IR will not.
> In fact, you could build your greenhouse from a non-typical design and
> use an insulated structure which has only relatively little open area
> for the sun to enter. Solar collectors can gather the needed level of
> light and project it into the windows. A hologram will filter out the
> IR and distribute the light to the plants. In this way you could even
> convert an existing solid wall building into a greenhouse which would
> be very economical to heat and cool.
> This design has proven as good and even better than traditional
> greenhouses in tests done at the Univ. of Pennsylvania.
> Many things can be done.
> Neal Van Milligen
> Kentucky Enrichment Inc.
> www.kentuckyenrichment.com <http://www.kentuckyenrichment.com>
> cavm at aol.com <mailto:cavm at aol.com>
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