Solar heating (ish)

[rosinante]

Hi all , I have a south facing detached bungalow , is it worth painting the western end black to absorb some of the sun's heat, I know that it won't be a discernable change in the rooms temperature but would it be enough to prevent the wall being a condensation risk, or am I just being daft,
Cheers
Chris

 

[Omniata]

Besides black absorbing more heat, it does release more, so could create a cold spot at cooler times.

White on the otherhand, whilst reflecting more, it releases heat more slowly...

Bit of a dilemma really, it's why a lot of heatsinks are painted black, and solar water heating systems panels are contained, usually, in a small greenhouse afair to contain and amplify the heat.

 

[brianblock]

Assuming it has cavity walls it probably wouldn't make any difference
If on the other hand it's solid brick, I wouldn't have a clue. But if I had to guess I would plump for no difference either

 

[Omniata]

Assuming it has cavity walls it probably wouldn't make any difference
If on the other hand it's solid brick, I wouldn't have a clue. But if I had to guess I would plump for no difference either

If it's solid wall check the DPM, and/or inject some of the siliconised resin DPM across 3 courses, will stop the damp and as the wall dries it will retain heat more effectively.

 

[rtbcomp]

I think it might help, the wall will heat up more from the sun than it would due to conducted heat through the brickwork from inside. The higher temperature would transfer some heat inside and there might even be a "storage heater" effect. One room in my workshop faces south with no windows, and it's always warmer than the room on the north side of the building.

My shed has a south-facing black fibreglass on chipboard roof and on a sunny day it's almost too hot to touch on the inside.

If the wall is warm it would reduce heat loss from inside.

 

[rosinante]

Yes it is a cavity wall, I hadn't thought of that, Rbt ,that is a good point,
Chris

 

[rtbcomp]

The wall on my workshop is solid 9" brick

 

[ibrooks]

If it had been a solid wall then what you would have gained in the sunshine would be offset by what you would lose when it's dull due to "black body radiation". As for it not conducting "out" as fast - the bigger the thermal differential the faster the heat flows from one to the other so on a cold dull day you would be sucking heat out of the room at a faster rate.

A better plan would be a "coke-can" heat exchanger on the outside and duct the heat inside with a couple of flap valves to prevent it working in reverse.

 

[rtbcomp]

If it had been a solid wall then what you would have gained in the sunshine would be offset by what you would lose when it's dull due to "black body radiation". ...

True, but in my experience there is a net gain.

 

[gaz1]

not if you use thermal banking you can use the south wall

http://www.builditsolar.com/Projects/Sunspace/GreenhouseHX/GreenhouseHX.htm

you then could use a wood stove to top the heat at night

 

[GW8IZR]

See the greenhouses in Victorian walled gardens were clever, the front glass area pointed south to use solar energy and the back walls were the compost bins, the heat from decomposing warmed the back wall of the glasshouse.

 

[Omniata]

See the greenhouses in Victorian walled gardens were clever, the front glass area pointed south to use solar energy and the back walls were the compost bins, the heat from decomposing warmed the back wall of the glasshouse.

They were also, more often than not, dug down into the ground to take advantage of the consistent sub-surface temperature...

 

[eSCHEn]

Yep, that's how they grew and ripened exotic stuff like pineapple back then.

 

[GW8IZR]

Yep.. nothing new under the sun really :-)

 

[brightspark]

no need now we have global warming

 

[eSCHEn]

Still can't ripen a decent melon here though!