Have a question about passive solar heating placement

the19thbear

New Member
Joined
Nov 22, 2021
Messages
5
Hi. I am completely new to this, but I have been looking at this design:
and this

Solar air heating.

So not your "normal" solar solution. Just used for heating and nothing else.
Has anyone done this?
I am thinking of mounting it on my garage ceiling (towards the south - I live in the northern hemisphere). And then have a metal hose going down into my garage, via a fan.
I am thinking the "going down" is a bit of a problem, since the heat wants to go up. So my question is, if anyone has any practical experience with this?

Also, my main question:
I live in Denmark. During the winter it can get very cloudy. Sometimes we don't have direct sunlight at all for long periods of time.
How will solar air heating perform then?

Thanks:)
 

diyernh

Solar Enthusiast
Joined
Feb 5, 2021
Messages
111
Hi. I am completely new to this, but I have been looking at this design:
and this

Solar air heating.

So not your "normal" solar solution. Just used for heating and nothing else.
Has anyone done this?
I am thinking of mounting it on my garage ceiling (towards the south - I live in the northern hemisphere). And then have a metal hose going down into my garage, via a fan.
I am thinking the "going down" is a bit of a problem, since the heat wants to go up. So my question is, if anyone has any practical experience with this?

Also, my main question:
I live in Denmark. During the winter it can get very cloudy. Sometimes we don't have direct sunlight at all for long periods of time.
How will solar air heating perform then?

Thanks:)
Just quickly reading this. One question. If it's cold outside, and there is no valves or dampers, wouldn't you get a cooling effect? ie warm air from your ceiling entering the heat exchanger that is radiant cooling to the night sky. That would drop the air temperature and pump cold air in at the floor. Usually people heat in the winter, when the days are short. Those long nights can create more cooling than the short days heating.
 

the19thbear

New Member
Joined
Nov 22, 2021
Messages
5
Yes, this solution would need a part where you effectively close off the connection to the heating unit.
So you would manually need to close it off at night time. Otherwise it would cool the room.
But when there is enough sun, you should turn it on.
 

Supervstech

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Sep 21, 2019
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Belmont, NC
Hi. I am completely new to this, but I have been looking at this design:
and this

Solar air heating.

So not your "normal" solar solution. Just used for heating and nothing else.
Has anyone done this?
I am thinking of mounting it on my garage ceiling (towards the south - I live in the northern hemisphere). And then have a metal hose going down into my garage, via a fan.
I am thinking the "going down" is a bit of a problem, since the heat wants to go up. So my question is, if anyone has any practical experience with this?

Also, my main question:
I live in Denmark. During the winter it can get very cloudy. Sometimes we don't have direct sunlight at all for long periods of time.
How will solar air heating perform then?

Thanks:)
Ok, if this is a gravity setup, you will need a low side input, and a high side output for circulation to happen. If a fan is incorporated to the design, that is less of a concern. Place it where maximum sun exposure is.
Certainly, lack of direct sun will reduce the output of the box. If you use the soda can design, and all the cans are sealed together, the airspace forms a thermal blanket, and the cans can get the air hotter, with a reduced airflow setup… not sure if this in built into the design.
 

circus

Solar Addict
Joined
Jul 8, 2021
Messages
271
Cool! How the heat during cloudy weather? I mean *very* cloudy :)
Not much heat, but in Wisconsin the humid air comes from the south, Gulf, and isn't very cold. Bitter cold comes from the north, Canada, and is dry. Heaters works the best when needed the most.
 

the19thbear

New Member
Joined
Nov 22, 2021
Messages
5
Let me correct myself. How is the heat production from the passive solar, when it is very cloudy?
Thanks:)
 

the19thbear

New Member
Joined
Nov 22, 2021
Messages
5
Ahh I understand. Horrible. Bad. Forfærdelig. Lort. aarrrrrrrgh (I get it).

Will have to pass on that then. Living in Denmark with lots of clouds is probably not worth it then.

Thanks:)
 

circus

Solar Addict
Joined
Jul 8, 2021
Messages
271
For whoever is thinking about building a collector it's better to have lots of air flow. Cooler collectors radiate less. The 155° mentioned on the video was silly wasteful. A couple degrees above room temp is ideal.
 
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Bossrox

Solar tinkerer
Joined
May 21, 2021
Messages
157
Location
Columbia, SC
I just built my 2nd solar furnace I'll be posting on youtube soon but my 1st solar furnace is up there already @
& it puts out fantastic & was really easy to build.
 

rcrracer

Solar Enthusiast
Joined
Apr 10, 2021
Messages
86
"Build It Solar" website has many examples of that type of solar heater. A few years back that type with two layers of window screen was by far the most efficient. I some calculations in Excel and it appeared that possibly five of layers of screen might be the most efficient. Seems like they compared one layer of to two layers, and I used the result difference of the two and came up with five screens. (basically made up some numbers based on my probably flawed logic)
I'd try vented aluminum soffit behind a couple or three screens.
https://www.builditsolar.com/Experimental/AirColTesting/Index.htm
It seems as if they are up to three screens. This all may be from 10 years ago.
 
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