Self powered heated greenhouse

let's see I'm at 43 degrees latitude and England is .....:rasp:

 

Thanks for the replies everyone. So it seems that it is not something that can be bought off the shelf.
I am actually an electronics design engineer and wanted to design and implement it as a project during my spare time. My problem is that I don't have a greenhouse or the space for one. So I wordering if anyone would be interested in allowing me to install one on their greenhouse?

 

Are you planning on developing something that may get marketed some day?

 

@ Lori
It would have to be pretty powerful to replace a 12"duct fan

 

Oh, @Hex_2011 what size greenhouse do you have? Must be huge! Any pics?- would love to see them

 

Its hobby sized about 175 square feet of floor with a 10ft apex.

 

Ive just had a cunning idea for cheap greenhouse heating ................................but its top secret . I`ll tell you after its paid for my new yacht.

 

Well, I'm not sure how much demand there is for this type of product. I would quite like to get a prototype working first and see how well it performs.

 

My greenhouse heating and cooling system cost £200, divided by 7yrs works out to about 55p a week

 

@Hex_2011 that is a really cool greenhouse. Lots more square footage than I have.

Glad you've got a moderating system that is so inexpensive. I ran a heater with natural gas one winter and it cost me $200 per month - did that one winter only as that's way too much. Then again, I don't know what your weather conditions are compared to mine. Which growing zone/part of the world are you from?

 

I`m in a very sunny uk My thermometers tell me its 29.6C in the shade and 36C in the sun with just a whiff of a breeze. Traditional glass box greenhouses have never made any sense to me, they bake in the summer and freeze in the winter My neighbours greenhouse is a single glazed glass box variety, whitewashed, with the door and vents wide open. Mine is in full sun, triple glazed with no whitewash/shadecloth blocking the light. I have the fan set to run at 24C and turn off at 21C. The fan speed is turned down so it runs more or less constantly at a low level rather than blowing a gale for short periods. The fan uses less power that way and provides the same amount of cooling over the time, its a little like the hare and tortoise race, slow and steady vs hell for leather in fits and starts

 

@Hex_2011 that is a lovely grand sized greenhouse! A couple of winters ago I heated my little 48sf hobby greenhouse and it cost me $200 a month for the natural gas. So I didn't do that again!

What is your climate? We go down to -30c some nights in the winter.

 

sorry @Hex_2011 there is some weird time warp happening and my earlier post did not show up for ages so I had thought it was deleted... apologies....

 

No worries, there was me thinking it was heatstroke Its hard to say what normal winter temps are here as we dont get normal winters anymore but it used to be -6C to -8C with the occasional -12C. Sounds positively tropical compared to your -30C $200 a month is a lot but might be about right for an 8x6 with twinwall polycarbonate glazing, to keep it 1F above freezing when its -30c outside you`d need at least 1300w of heat.
Do you get a lot of winter sun?

 

-30c is our extreme - You're correct in thinking I don't have to worry when the sun is shining and we get lots of those sunny days but the temps drop dramatically and then in lock step with the outside after the sun goes down unless I have heat on. I've decided that it's cheaper to run lights inside than heat in the greenhouse so this winter I'm going to play with growing some veggies and things inside