Using Trombe wall principles to heat living area..

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Stephendnz

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#289449 6-Sep-2021 23:45

Hi guys.. wondering if some of you ventilation experts here might be able to help with a question I have about Trombe walls. I don't actually plan to build one as much as try and employ the principles of them..

I have a sunroom on the direct north side of my house and when the sun shines.. it gets as hot as hell.. it opens into our main living area.. but when I open the door between the two areas.. it brings some of the heat in, but not so much that it makes that much difference to the warmth.. I am on the Westcoast.. SI. And it can still be pretty cold here, even when the sun shines.. and sometimes by the time the sun gets around enough to shine directly into the living area.. its gone.. but the sunroom has been baking since early morning.. 😁

So I was thinking that I would use the principles of the Trombe wall. by creating a hole top and bottom on the connecting wall... with a vent and non-return flap on both.. plan being that the cold air gets drawn into the hotter sunroom through the bottom and the warmer air gets pulled in through the top vent into the living area..

Obviously, it's only going to work when the sun's on it.. and I need the non-return flaps to make sure don't get cold air in when not sunny..

So wondering 1. Anyone has done anything similar.. 2. Will I need a fan to aid circulation.. 3. Anything I am missing here?

Pic attached of the Thombe wall.. even though they are usually built with closer spacing between the glass and the thermal wall.. I have seen one with a room space of about 1.5 mtr.. like a narrow sunroom.. and works super well.. but also has a huge wall of glass and a rock wall..😁

Thoughts.. ??

mattwnz

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#2773324 7-Sep-2021 00:26

Does it need the airflow? I have seen one built, and the glass heats the concrete thermal mass, and that then radiates the heat into the room through that thermal mass. You an do something similar with passive solar design and using windows to heat concrete floor slabs.

raytaylor

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#2776265 10-Sep-2021 22:06

Fill the sun room with large rocks painted black.
Rock, brick and stone doesnt store as much thermal energy as water, but it does retain heat and slowly radiate.

If opening the door between the sun room and the living space isnt bringing much of that heat in then adding wall between them wont help. What is probably happening that as the sun room is a small area, it heats up quickly, but as the lounge is a larger area, it will heat more slowly as the heat is less concentrated over a larger volume of air.

Try it with a fan. Open the door 30cm and place a desk fan on the floor aiming out into the sun room on a low speed. This will create positive pressure in the sun room, thus causing the warmer air in the sun room to re-enter the house higher through the same gap in the door above the fan.

That should help you understand the capability.

Also see if you can double glaze your sun room by some means.

Ray Taylor

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wellygary

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#2776269 10-Sep-2021 23:01

raytaylor:

Fill the sun room with large rocks painted black.
Rock, brick and stone doesnt store as much thermal energy as water, but it does retain heat and slowly radiate.

+ this lots...

A big reason thombe walls work is the solar energy heating the massive wall which then heats the air

It’s a similar theory to underfloor heating vs a convection heater ...every thing in the room is warmed .. not just the air

when you open the door you are diluting the watts are by a huge degree , hence it won’t heat the house well..

You could try paving stones on the floor... and you could throw a old fish tank in there too.. anything to absorb heat... air by itself is not able to store much heat...

raytaylor

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#2776329 11-Sep-2021 11:19

I wish i got a photo but we have a customer whose house is very large and open plan with large windows with a superb view down the valley.

Beside the fireplace and in front of many of the windows are large columns of river stones which are held together in a circular column shape by a tube of large diameter steel mesh.

Its brilliant - you can go into the house in the evening and the columns near the windows are still radiating heat at 9pm after absorbing it during the day. And the fireplace becomes more efficient as they dont need to run it overnight as the columns beside it will absorb the heat in the evening and release when the fire goes out, so its still a few degrees warmer in the morning and the heat pump doesnt need to work as hard.

Ray Taylor

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Stephendnz

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#2776343 11-Sep-2021 12:29

Thanks everyone for the good suggestions.. Ray I had actually used the fan technique. but I think I had it back to front. I had placed a small fan at the bottom of the open door, but blowing the air out into the living room..in an attempt to extract the hot air from the sunroom.

I have just changed it over to your suggested method.. and so far I think that seems to be workking better..

Yes one day I would love to have a house in which I could incorporporate some of those passive heating option.. unfortunatly this old 1930's weatherboard ouse on somewhat shaky piles is probably not the best place to try that.. Hence my looking for easy workarounds..

Thanks again fo the help.. i think i will go ahead and make the holes.. depending on how that goes, i may add the fan option at a later date.. With the air blowing into the room.. which I hadnt thouth of that to be honest..

Actually just looking at the door between the two rooms.. maybe I will just get the hole saw out and put a 50mm hole in the top and bottom of the door.. and see how hat works..

In the house i mentioned in my OP they had a few strands of wool suspended from the top of the top opening.. and you see when it was working.. at first the wool was just just fluttering a little.. but when he closed off the entrance to his Thombe 'room' within just a few minutes you could see the wool strand were blowing almost horizontal, such was the force of thr warmer air blowing in.. no fans needed..

Cheers, and again thanks for the help.. I shall post some pics when.. and if it works...