Has anyone been watching "It's Not Easy Being Green" on BBC2? The bloke who presents it is an ex-Army engineer, and he had this nifty idea for a greenhouse heat exchanger. I was wondering what you guys thought of it?
If you haven't seen the program, his idea is this: because heat rises, the hottest air in the greenhouse is at the top. He proposes to use a fan to blow the hot air down a plastic pipe and into a hole dug in the ground. The hole is filled with ground-up old glass bottles, which retains the heat. The theory is that the glass slowly releases the heat at night, keeping the greenhouse warm.
The physics of it makes sense to me, but what do you think?
i didnt catch-if he said....-how he was going to power the fan to get the heat down...wouldnt this negate any saving of power ?
i also-uncharitably,-wondered how much power that glass grinder used..and why oh why do these programmes seem to have unlimited money to lash about..
just spend 380 quid on pigs and housing....
just make a waterwheel(by the way-it looked like the wheel was made with plywood-please tell me it wasn't-wont the whole thing diintegrate after a few months?)
just grow a giant soup straining moustache
i think i may just be in a grumpy mood.... >:(
Grumpy bum. No i agree Kitty it all seems a bit slap happy[bodged]. Did you see the aquaduct they had built to supply the water wheel? Had more leeks than......next doors allotment. Its called TV.
A path made of paving slabs down middle of greehouse does same job heats up in day.. similar principle to night storage heaters .Also I have been told but never tried it that empty plastic bottles filled with water placed round greenhouse do a similar job . I wouldnt want ground glass anywhere near my lottie ... cheers ..Jim
I quite agree about the amount of money they seem to throw around on the program, and the amount of waste they seem to generate....and the fact that they just happen to have a stream with which they can power a waterwheel, and just happen to have an army of helpers. For some reason, it also irritates me that he uses a battery-powered screwdriver instead of a normal one!
....but having said that, if I had a stream in my back garden, I'd love to have a water wheel! (by the way, I think it was made from "Marine Ply" - but I have no idea what that is!)
I think I'll be sticking to the old bubble-wrap insulation method to keep the greenhouse nice and toasty!
Marine ply is ply that won't fall apart in water -for a while :) You can buy boats made out of it. It's v. expensive and personally I'd impreganate it with West Epoxy or the like -also v. expensive. That said there are 30 and 40 year-old yachts made out of it..
I saw them grinding the glass -didn't seem to be sharp at the end of it -I've read about a similar thing with rocks, and I guess you could use a solar powered fan, but it didn't look a very big hole to heat a greenhouse and I'd be more interested in something that would go through the winter. Still with weather like this there's some advantage in evening out the temperature -I'm throwing away heat in the day and having to move plants indoors at night.
like growmore said-biiiig buckets of water that heat up during the day are a much better option-and you water your toms with tepid water rather than {{{cold}}} water-less shocking for them!
northener!yes-made me giggle a bit-they said that it would need a 'few gaps ' filling in-oh aye!more like remaking!
i was hoping this series would be a bit better than this-instead it seems its turning out more like a lawrence llewellyn bowen mdf job!
>:(harumph!
I do have various tubs and cans of water around the greenhouse -but I'm not sure how much good they do. Still, as you say the water is the right temp. also, since they're lidless, they should keep the air a bit moister and deter the dreaded spider-mite, maybe, please.
It's 1 gallon for every square foot of glazing. (this is with no bubble wrap). Bubble wrap keeps the GH approx 3C higher than outside, but not for a prolonged period.