[Strawbale] Drilled Well to Heat Greenhouse?

[Speireag Alden]

Sgrìobh Tim Chamberlain:

>   With a heat source of 50F, without a heat pump, you don't have 
>much of a temperature difference to push heat into your greenhouse. 
>You're also going to impede heat flow using a loop of PEX in the 
>well compared with pumping well water directly through the floor. I 
>think you would be better off using a wood stove or active solar.

     Yeah, I'm inclined to think that you're right, now that I think 
about the small differential.

     I didn't include the other design details, and should have: 
Correct passive-solar orientation, earth-bermed, with an insulated 
earthen roof on the north side.  Hot compost pile going year-round in 
a corner (actually three piles, each at a different stage at any 
given time).  Several thousand water-filled 2-liter PET bottles 
buried generally just under the soil, to provide greater thermal 
stability in the soil and pretty good freeze protection.  Attached to 
the house on the west side, with exhaust air from the house going 
into the greenhouse.  Possible chickens.  Small sauna located in one 
corner, which will lose heat to the greenhouse before the greenhouse 
passes it to the world at large.  Probable night-time insulation, of 
some sort.

     So there will be plenty of heat sources, and I won't actually 
mind if it freezes.

     However, for points south, where the groundwater is warmer and 
the freeze-resistance is easier to achieve, it's an interesting 
notion.  A heat pump without the compressor.

Sgrìobh RT:

>I don't theenk so. At least not without large volumes of water being
>circulated (ie requiring a 1/2 HP or larger pump) and a compressor
>in there somewhere.

     That gives me an order of magnitude for sizing.  Thanks, RT.

Sgrìobh Lee G. Weaver:

>$1000 for a 20 foot well that would take maybe 2 hrs to hand drive.

     Ah, no.  Not in this land of granite rock.  I hit bedrock about 
six feet down, and then water about twelve feet after that.  But on 
"unimproved" soil I can swing a pickaxe and bounce off of a rock two 
times out of three.

Sgrìobh Shody Ryon:

>There was someone in Canada that was using passive
>solar as the only heating system to warm his
>greenhouse in the winter. I think the idea he was
>using was to build long in the east west direction and
>narrow in the north south direction to take advantage
>of the solar energy. As I write this it, doesn't make
>a lot of sense.

     Thanks, Shody.  Makes perfect sense to me, although I'm skeptical 
that, without other design details, he's doing more than shortening 
his winter within the greenhouse.

Sgrìobh David Neeley:

>There was also a family that heated their water for some time with a
>water hose run through a compost pile. I wonder if such a compost pile
>might also provide heat for growing plants in a greenhouse, without
>relying entirely upon sunlight for warmth? (IIRC, in many areas such
>as Speireag's sunlight can be at a bit of a premium at times).

     Yeah, in December there's not a lot of sun, between the season 
and the cloud cover.  But there will be a compost pile in the 
greenhouse, so that will help.

     I remember reading about that family and their hot water.  Trés cool.

     And thank you for the ideas and links, Barbara!

-Speireag.

-- 
Fill the molten glass.
Sit with singing summer frogs.
Think on Jack's wedding.