~ CHEAP HEATING FOR YOUR GREENHOUSE ?? ~

[Hattie the Hen]

During my bout of sickness I have had plenty of time to poke around on my laptop. One of my most useful finds has been this link to a very interesting site:

http://www.thefuelman.com/blog/index.php?p=425

I think it's something I would love to try if I had a greenhouse & was a little fitter than I am now -- old age is catching up, rapidly...!!

***Please read the rest of this site as it is full of very useful info for you 'handy' types or your DH's/SO's. [They are going to so hate me......!! ]

:rose Hattie :rose

 

[HiDelight]

that is amazing Hattie ..I so yearn for a real greenhouse ..something I could sit in and enjoy during the winter ..a combo potting shed/greenhouse would be perfect for me except I would never come in the main house...

this is an awesome idea thanks for posting

and it is sooooooo good to see you are feeling bit better my friend

 

[digitS']

Remember those fruits and veggies for your vitamins, Hattie!

I'm going to take slight exception to the author and the builder of that greenhouse heated by compost. It seems to me that running cool water in tubes thru compost is just a good way to cool-off the compost rather than heat the interior of a greenhouse. I think it would take a fairly massive pile and a fairly small greenhouse to get very far down the road with this idea.

Glazing, of just about any type, loses heat at a fairly good clip. Insulating material can be spread across a greenhouse overnight when heat-loss is usually greatest, but that's another story. Double glazing helps but the additional material, decreases light to the interior. That light is necessary for plant growth and makes a VERY important contribution to heating.

I feel that the very best things one can do is to
* maximize the penetration of light,
* cut down on air leaking from the greenhouse, and
* use something on north walls to retain heat within the structure.

A conventionally framed and insulted north wall and even north side of the roof will go a long way towards retaining heat from the daytime sun while protecting against heat loss at all times. Certainly, glass or plastic glazing material doesn't need to be on the northside.

Southside, the angle of the glass or plastic should be as close to perpendicular to spring/winter sunlight as possible. Obviously, the sun is moving in the sky (at least from our perspective ) and greenhouses don't usually pivot to follow the sun. But, especially if you are trying to maximize light inside the structure and minimize reflection - you would want light coming in at a right angle.

Back to the compost generated heat: I think we often over-estimate the amount of heat kicked-out by compost. 1000 Btu/hour per "active" ton of compost seems to be about maximum Penn State U, Big Download! . Without any remarkable temperature difference, wind, leakage, etc. - greenhouse glazing will lose 1 Btu/hour per square foot ag agency, New South Wales . Big pile - - little greenhouse.

To minimize the cooling of the pile while taking maximum advantage of the heat - I would put the compost pile INSIDE the greenhouse under the growing bench. You probably want to have a bench anyway and the space under the bench often has little use. A 4-foot wide bench, accessible from 2 sides would be very useful. Now, I'm not sure about interior air quality. Ventilation for the pile, may be very important.

Or, just do a better job with available solar energy. Pumps, water . . . I don't see the need.

Steve

 

[modern_pioneer]

I wonder if I can place a compost bin in my new green house?

 

[patandchickens]

Well of course it can be done for large coldframes at least, it was a common traditional thing to do like 100-200 years ago, when manure was plentiful (not to say "excessive" ) and labor was cheap. Running air-filled pipes (you would not want *water*-filled, that seems like a bad idea in several ways) would be a bit of an improvement on the old systems in some ways, but you would not get as much heat out of it that way, and also it is susceptible to the same major problems that the old style things had.

The thing is, there is a REASON why people switched away from manure-fuelled hotbeds as quickly as other options became available, and that reason is that they require quite a lot of management. The heat is very unreliable -- it cools down pretty fast -- and that is a LOT of material to have to move, turn, remove and replace if you want to keep consistant heat over more than a couple weeks.

I utterly agree with Steve that ingenuity would much better be expended on better physical design of greenhouses, e.g. best-possible insulation and heat capture.

JMHO,

Pat

 

[digitS']

I started the furnace in my greenhouse this morning. This is about the earliest ever and fortunately, the outdoor temperatures remain about 6F above normal, unfortunately we are getting very little sun.

The new south window is supposed to go in the house - TODAY!

The greenhouse heat always goes on about this time or a little later. I wonder what the contractor will think if the very first things we move back into that south room - is a parade of cookie boxes full of tiny plants from the greenhouse.
And, OFF will go that furnace for maybe another week .

Steve

 

[aaron28]

That's a pretty neat concept really. That guy has his thinking cap on for sure. I've done something kind of weird before. I put a heater blanket under some pots and a plastic sheet over top. It scared me a little bit so I stopped doing that. I was afraid I was going to light something on fire.

 

[kyle]

this site has some really good information, which i hope to implement into my greenhouse when i move to canada.
http://www.sunnyjohn.com/indexpages/shcs_greenhouses.htm