Rainsing my greenhouse

[W. Beetus]

Or I could use some of these spent nuclear fuel rods from Japan and build my own covered water pool to put them in. The steam could go into pipes warm the greenhouse and go back to the pool. I bet my municipality doesn't have any bylaw against that kind of system. :rollhappy:

That sounds like a great idea!! As long as you don't have very many power outages, it would work wonders... oke:

 

[Shiva]

Here's a new idea!

Although a solar heat sink could never get warm enough in my greenhouse to be effective, why not put it outside? Here's what I'm thinking: buy the largest possible used swimming pool with winter cover and paint everything black to absorb the sun's heat. Then I would fill it with water from the small river beside my property in spring and let it warm up over the summer. Meanwhile, i would dig up part of the floor inside the greenhouse and line the hole with panels of stainless steel soldered up together, large enough to accomodate the water in the swimming pool. As the temps get cooler outside, I could pump the hot water inside the large tub built in the g/h. The tub would be closed on top and come up three feet above ground. The top would then be perfect to put those orchids on who like more heat while the rest of the g/h would remain cooler for the cooler loving orchids. I would't bother running pipes in the ground to fill the tub. I could do that from outside before it gets too cold. Any thought on that?

The question is: how long would the stored heat last?

 

[likespaphs]

hours?

 

[mormodes]

There's an old book written by James C. McCullagh called 'Solar Greenhouse Book'. See if you can get a copy via interlibrary loan. Or Amazon has copies available for $0.79 US. It's an old book, my copy was printed in 1978, but the basic information hasn't changed much. Lots of information. He discusses everything we've suggested here but in-depth. Including your pool idea.

 

[Rick]

There are sites with calculators to figure out this problem Shiva.

One thing you need to know is how many BTU/hour you use during a typical night.

You would need a pretty impressive tank to store enough water to make it through the night hooked up to an efficient solar heating panel to do this. Other wise I guess you are looking at a small lake for a total passive system.

 

[hchan]

If you're considering passive solar as supplementary heating (I think it's clear total passive solar probably won't work for you) situated outside the gh, how about a trombe or water wall? You could build one up against one of your existing walls, just cut some vents into the cinderblocks for the air circulation principle to work. In summer when it's hot, close the vents to minimize the heating effect, in winter open the vents up to get the heat. The construction costs should be reasonable. I think the challenge could be that your gh is square so the surface area of the wall wouldn't be very big relative to your gh volume. I wonder whether it's possible to slope the wall to maxmimise the solar collection area?

 

[goldenrose]

Charlies Greenhouse supply sells a bubble wrap system for inside the GH. Its heavier than normal shipping BW, and you apply it with spay adhesive so it fits tight and stays in place easier.

I've tried it, in fact Menard's & Home Depot have spray adhesives, they all seem to work to a point but have to be reapplied, my guess is the high humidity.

Ed M replaced all his bench supports with 55 barrel drums (blue plastic) full of water. They were used barrels that he got for $15 I think. I think he said he paid about $300 so that would be about 20 barrels. I think his GH is about 1000 sf. He said he cut his gas heating bill down dramatically. He says by next winter he wants to add a solar hot water heater to get more heat into the barrels during the day.

The space under benches is usually wasted space, but you can use anything that fits from barrels to stock tanks to add a thermal mass.

I don't know how insulating your flooring is, but a lot of heat is lost to ground, so adding a insulation barrier to your flooring, and covering in pavers can help a lot with adding thermal mass to your GH even if you don't put in a floor heating system.

I tries insulating the floor one year, did notice much difference & with all the water draining on it, it wiped it out in no time!
I have use about 3/4's of the bench space below, have plexiglass shields.
People seem to overlook the fact that even though there might not be sun shining, the water is heating up during the day & that heat is being released hopefully at night. My 2 rainbarrels are in the middle of my GH on the west side so they don't get much direct sun but they do sit about a foot from the furnace & help channel the heat when the fan is on.
I've been using all these techniques over the years but this year I replaced any older bubblewrap, resealed everything & sealed my vents. There is the 2" PVc pipe vent for outside air for the furnace & yes I have to manually open/close vents but it's worth the $50-100 I saved each month & I would think we had a pretty average season for temps.