Allotment Gardening Advice Help Chat

Chatting => Design and Construction => Topic started by: tinyallotment on July 10, 2015, 07:31

Title: DIY Greenhouse Heat Recovery System
Post by: tinyallotment on July 10, 2015, 07:31: As my dome seems to actually becoming reality I am looking for a way to regulate the temperature both day and night.

I am going to have some vents as a back up just in case the dome overheats but this would be a worst-case scenario. I do not want to loose the heat generated during the day. I would rather store it to be released over night.

I'm sure there are countless commercially available systems out there but my system needs to be cheap and DIY.

I'm thinking, a solar powered ducted fan (http://"http://www.ebay.co.uk/itm/12V-4-Boat-In-Line-Air-Blower-Bilge-Head-Galley-Engine-Ventilation-Cooling-Fan-/331414401358?pt=LH_DefaultDomain_3&hash=item4d29d6714e") taking the hot air down to a loop in an insulated IBC full of water and back out again.

This should take hot air from the top of the dome, cool it and return it to the dome during the day. Come night time the heat will slowly leak back out from the water into the dome maintaining the temperature over night.

Would this work?

Paul
Title: Re: DIY Greenhouse Heat Recovery System
Post by: JayG on July 10, 2015, 08:14: The physics and maths of thermal storage is beyond me I'm afraid, especially if you wanted your system to provide warmth outside the summer months - a fairly recent thread on the subject here which you may find helpful:

http://chat.allotment-garden.org/index.php?topic=118332.msg1383695#msg1383695
Title: Re: DIY Greenhouse Heat Recovery System
Post by: Annen on July 10, 2015, 08:58: JRKO installed a solar fan in his greenhouse a couple of months back, might be worth a read. http://chat.allotment-garden.org/index.php?topic=107298.0 (http://chat.allotment-garden.org/index.php?topic=107298.0)
Title: Re: DIY Greenhouse Heat Recovery System
Post by: GrannieAnnie on July 10, 2015, 09:12: I think the 'reservoir needs to be underground to be able to hold the heat in. I used to watch Dick Strawbridge in "It's not easy being green" on TV.

OH was going to build me one, but it never got done.

Here is something similar, but I haven't read all of this article yet.

http://www.greenhomegnome.com/heat-sink-self-heating-greenhouse/
Title: Re: DIY Greenhouse Heat Recovery System
Post by: brokenglass on January 20, 2016, 12:02: Love the concept but fear that the Solar panel would be stolen!
Title: Re: DIY Greenhouse Heat Recovery System
Post by: Trikidiki on January 20, 2016, 13:12: I have a solar panel charging a battery on the allotment with a similar idea in mind.

We don't have a general theft problem but I have fixed mine so it is flush against the roof glass of the greenhouse, You have to look really hard to notice it is there. It should be fairly easy to disguise a panel as a cold frame if you don't have a greenhouse.
Title: Re: DIY Greenhouse Heat Recovery System
Post by: tinyallotment on March 22, 2016, 08:48: Yes theft is always a problem but as you say I will try to disguise the panel as much as is practicable.

Paul
Title: Re: DIY Greenhouse Heat Recovery System
Post by: oakridge on March 22, 2016, 10:57: The sustainable living programs that Dick Strawbridge did some years back covered this sort of thing. I have a water butt inside the greenhouse which makes a Contribution.
Title: Re: DIY Greenhouse Heat Recovery System
Post by: tinyallotment on March 22, 2016, 11:18: Thanks oakridge

Yes we store about 600 litres of water in out small tunnel and at the moment about 1000 litres in the dome. It make a difference to the temperature in the dome but I cannot quantify it at the moment because I need a data logging thermometer

Paul