[marek]

Since I lost the glazing on my 2nd greenhouse last week, I seem to have an abundance of broken glass, instead of sending it to the tip I could have a go at creating a heatsink, I remember Dick doing this in his Green TV show, also shown here
http://www.reuk.co.uk/Solar-Greenhouse-Heat-Sink.htm
There seems to be more talk about how to create one than the actual results, which makes me sceptical.  Anybody had a go at this?

Cheers,
Marek

[GrannieAnnie]

Havent had the courge to try it yet but I'd like to.  Especially in the polytunnel!  Think it would work in a polytunnel as well as in a greenhouse?

[cortina1498]

Hi Marek, I've had a go at this in my greenhouse, I used a large metal insulated box on the floor though, and filled it with pea gravel, fall pipe for the inlet, mounted into the top of the box, with the fan (12v ex-computer) mounted in the ridge end, and a small stub of fall pipe for the exit in the bottom corner, a 10w solar panel and a battery. The difference was noticable during the day, and at night it was about between 3 & 5 degrees warmer than it had been. Hope this is some use. cheers

[marek]

Good stuff, real life experiences.  Would you do it again?  How deep did you place your box or is it sat on the ground and have you lost much planting space inside your greenhouse?

I've got just about everything I need to do the project, an old solar panel from a solar pond pump with backup batteries included.  Loads of 12v fans, maybe I could use one with led's in (a phase I went through!), for the box, I've got an old bio filter box from a pond that I will use, this should combat against any high water table issues.

There is no reason why it cant work in a tunnel, just the area to warm is larger, so maybe 2 heatsinks, one at either end would pay dividends, or maybe third one in the middle, I guess it depends on the amount of air to heat.  I havent seen the algorithm that is used to calculate the mass of the heatsink material required to heat a specific volume of air (I'm not sure I really want to) :shock:

[cortina1498]

Hi, my box is 2' x 1' x 1', sited, in the corner,  on the concrete floor of my greenhouse. I didn't lose any space as it's under one of the benches. As to if I would do it again, the answer is yes, I am doing the same to my garden shed, mainly to warm it up on an evening.
cheers

[Trillium]

Do you think the gravel is as effective as the crushed glass used on the Not Easy show? I was very interested in that myself though I don't have a greenhouse - yet.

[cortina1498]

Hi Trillium, I'm sorry I can't answer that one as I have only used pea gravel and can't compare with anything else, but I do know it made a difference in my greenhouse and, hopefully, in my shed.
cheers

[ecowarrior]

I have installed a greenhouse heatsink as dick strawbridge did some years ago for tv however i have found that i had to increase the power of the fan as the air flow should be a min of 5 times every hour.To be effective.
Intend to replace with shcs system widely used in colarado which uses the whole of the greenhouse under floor powered from solar panels have estimated that it can be possible to store large amounts of energy in this way with low energy air fans through ducting passing under the subsoil.

[arugula]

That's very interesting ecowarrior, but this thread is over three years old so perhaps you could have started your own one. I also know that the Dick Strawbridge heat sink has been mentioned on these forums more recently, by me for one!