18 Nov
How many solar panels?
OK - I want to put my green house on 100% solar - what do I need to know about solar panels and what do I look for?
Then I was curious about my home - if I wanted to offset some costs what do I look for. I see lots of kits just don’t know which to get.
Lastly - storage can you store solar energy in a battery of some sort.
Posted by biire2u on 18.11.09 at 2:38 pm
There are lots of books you can get at the library for free or at amazon.com that go into the detail you need to be self-sufficient in greenhouse growing with only solar heat or electric for a source.
The problems arise in the winter. Often the sun is out with any intensity for only around 5 hours in dec-jan. The electricity production or generation of solar heat are very low during these months. Also the glass used in a greenhouse is very low in insulative properties so it loses more heat than it gains especially during the long nights.
What you need is some extras. Maybe a wood fired heater in the greenhouse, or a windmill if you have any windpower in the winter in your region.
You may also want to consider slide on insulating coverings. These would be either foam panels or fiberfill batts that you can slide over your glass at night to help retain heat much better.
There is a magazine I’ve been getting for 30 years that is now online and gives many many stories of self sufficiency in energy (and food, home and work for that matter). They have many articles in their archives for making greenhouses and solar panels and solar heated water.
Solar heated water is the most cost effective and best use of the sun’s energy in comparison to solar electric panels. In a greenhouse you are worried about heat more than electricity. A 3000 btu heater in solar might only cost $200. To make enough electricity to run a 3000 btu heater in electric might cost $2,000 and be more complicated and need batteries and so forth.
With solar heat you can just heat up a big tank of water during the day, with some black painted glass covered panels and blow the stored heat over some large rocks or bubble thru some water and let the stored mass give off it’s heat during the night. (You still need to cover the greenhouse with some roll-on roll-off insulation panels.
http://www.motherearthnews.com/Renewable-Energy.aspx
Posted by billrussell42 on 18.11.09 at 2:38 pm
For a greenhouse? photovoltaic solar panels?
The problem is that a greenhouse usually has a glass roof to maximize the amount of the sun that reaches the plants. Adding solar panels would reduce that.
The rest of your question is quite involved. Determine how much power you want the panels to develop, and from there you can get an idea of the size required, the batteries needed, etc.
You will have trouble making these pay for themselves unless you live in a warm climate where you get lots of sun all year. Also, you need an area to mount the panels that faces the southern sky and has zero shade.
For a large array, count of US$ 30-50k
Posted by dadof2 on 18.11.09 at 2:38 pm
tinyurl.com/lowcostsolarpanel it explains it all. I bought it and made a solar panel with my son. check it out.
Posted by George on 18.11.09 at 2:38 pm
You would be better off installing a geothermal system. You also have the advantages of the tax rebates to offset the cost.