DIY Greenhouse Heat Recovery System

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 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

- Air is a notoriously poor conductor of heat energy, actually a much better insulator! There air several types of piston units like you find on the rear gate of most 'Hatch-back'
cars that automatically expand to open a ridge line vent to bleed of hot air, as you wish to use this heat energy consider a simple system to pump; water up to your roof peak-
with a simple low pressure atomizing spray and collection.

This system would be very close in efficiency to the amount of energy iused up in an air to air heat exchanger ! The Automatically opening/venting roof peak vent being a safety
vent as further back-up !

4 th' Craft ! Big AL

Paul Andrews wrote: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 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

I have been looking all over the Internet for the answer, having come up with myself. I found your post while looking. The only problem I see is the condensation that will occur inside the pipe, and the resulting mold and mildew.
This is avoided in the systems that use perforated corragated pipe, rub through soil. The condensate just soaksinto the soil, and the soil web fights any molds.
So you might want to try this with a IBC full of soil,or a raised bed of some other sort.

I never really thought about condensation so I am glad you brought it up.

The tube from the top of the dome down to the water tank will be insulated so I don't think there will be a problem there but we will have to keep condensation in mind when we design the heat exchanger in the fish tank.

Any suggestions?

Paul

Just had a thought. What about using something like a car radiator in the roof of the dome or come sort of flat plate collector that I can pump the water through and back down to the water tank?

paul

How about keeping the radiator on the ground and blowing/sucking the air from the top of the dome through a vertical duct (like an upsized Heat Stick) to the radiator. If you can find a used (new ones are not expensive) electronics-rack fan, 120mm or larger, you should be able to get good air exchange without using a lot of electricity. You might also need a water pump to move the water. If you like to dig, you could set it up like a geothermal heat pump.