Heatsink?

[mic]

Hi

Have come across this, is it actually effective? I could cheat and plug in a fan which would be cheaper than an electric heater at least. What sort of heat would this give out?!

Solar Greenhouse Heat Sink | REUK.co.uk

Thanks

[veggiechicken]

Not a clue but here's another thread http://www.growfruitandveg.co.uk/gra...ink_43191.html

and another - http://www.growfruitandveg.co.uk/gra...reen_5930.html

[mic]

Great thanks. I have a spare kitchen extractor fan somewhere which might be ok to use, more power than a pc fan anyway

[mic]

what someone else did....

https://youtu.be/1hYxKa_CW0E

[fishpond]

Depends if you want extra heat or just enough to keep the frost/cold out.
To keep the frost/cold out store a 45 gall or bigger water butt in there.(keep it reasonably topped up with water-preferably in the morning)(also handy for the plant watering).

[mic]

the ideal is all year crops, so any heat at minimum cost

[fishpond]

Hi mic
You will also need light.
Providing you can keep your greenhouse frost free, you should be able to germinate most seeds, the problem is getting them to grow.
To grow, you need warmth and light.
Natural light from the middle of feb is good enough, but before then is not good.
Longer days=shorter nights.
Can you run grow lights of a solar charged battery? I have no idea.
Hope this helps in your quest.

[ESBkevin]

Mass will hold heat, some preppers build greenhouses into the earth half buried and place black tyre walls filled with soil opposite where the sun enters for collectin heat and slow release. A black water butt full of water is good for this as the sun heats it during the day and the slow release during the night helps maintain some temp. Another easy trick is the compost hot bin. It needs to be 3ft cube minimum to get decent heat. Fill with fresh manure or green compost or both, after about 2-3 days the heat generated will enable you to place seed trays on top while its freezing outside. You get about 6+ weeks heat before you need to replace the manure with more fresh and the used can go out for the garden or get dug into the greenhouse beds. There are potentially no running costs if you get free horse muck or whatever and they are natural and constant so reliability isn't an issue.

[mic]

not keen on manure as its in the garden, allotment might be different

few videos ive seen with the heatsink is to cover the top off and have a pipe sticking out which releases the air back into the GH.
but what if there wasn't a top? lets say the heatsink is filled with rubble/hardcore, and it just becomes the GH floor if I did a layer of small stones for the GH base? it would be a larger area to release warm air, but would it release too much hence people using a pipe as an outlet instead?

thanks