[permaculture] Re: Greenhouse design for southern climates

Arlene 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?

Thanks again,

Arlene


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:

> Arlene,
>  
> 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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