Insulated panels to absorb and retain IR heat

[ZeroEmission]

Insulated panels to absorb and retain IR heat

I am and electrical guy but I have been involved in an insulation project for a few weeks and I have got to come up with an idea about that.
The point is that I would like to build a black flat panel made by a material with a high thermal capacity (i.e. that can retain solar IR heat as much as possible).
The trick here would be to cover this flat panel with a sheet of plexiglass on standoffs. If I make the standoffs around 1/4" and seal the plexiglass, I'll mimic a double pane window and snuff the convective heat transfer.

------------------------------- PLEXIGLASS
AIR
------------------------------- PLEXIGLASS
AIR
############################### BLACK MATERIAL

The plexiglass will allow sunlight in, but will not transmit the radiated LWIR. If the inside box surface is blackened, that'll maximize the sunlight absorption.
The heat should be retained as much as possible into the inner black panel to be slowly released to the inside during the night.
What kind of black coated material would do the job best?
Hope I have been clear, sorry but I am quite new to insulation materials. Any help appreciated.

 

[bithkits]

Try storing the heat in solid concrete (like in basement) by means of a water piping system that runs through the concrete. Very effective.

I assume this is for a house? I don't think you will find a material that can store enough heat energy to release slowly the whole night.

Adriaan.
I am an Engineer/part time student (Mechatronics) from South Africa.
Advice from lecturer: "Be warned - when you go into industry your boss will give you a thousand things to do and he wants them done yesterday!" So far he is right...

 

[IRstuff]

I think you'd be better served by improving your house insulation

TTFN

FAQ731-376

 

[jedward]

I have often throught the best material for your type of application would be pure water with the addition of a dark dye and some type of growth retardant. Water has a high heat capacity and can be pumped around as may be required or moved by convection- with proper design.
I think this has been done on rooftop energy collectors.

 

[ZeroEmission]

Thanks a lot for all the useful tips.
What I had in mind is not just insulation or thermal solar collectors.
The idea is to couple insulation with a heat pump (i.e. space heating).
During the day we could heat a loft using the hot air in the heating chamber between the glass and the roof surface.
The hot air will go up the sloping roof creating a high pressure point, a small air pump powered by a PV solar module will force the hot air down a duct which will convey the air into the indoor loft space.

 

[unclesyd]

You might want a to investigate coatings.insulating ceramic, such as those offered by Nationwide Coatings.

http://www.nationwidecoatings.com/prod10.htm

 

[xqv]

a mineral filled phenolic might be a usfull here.

 

[tr1ntx]

4 or 5 years ago some company began promoting "radiant heat shields" for home attics. Some sort of insulated panels that were either laid flat on the joists, or if you used your attic, could be applied (stapled I guess) to the sloped underside of the rafters. I don't know if they were simply the foil-coated foam insulation panels or what. I never saw them in-person, just the ads. They were to stop the radiant heat from the hot roof heating up the ceiling.

Maybe you could get foam insulation panels (or whatever they were) but with a black cover instead of foil.

 

[dragracer9]

Water has the highest thermal capacity without getting into exotic materials. Black carbon will trap the IR energy the best. Copper is a great thermal conductor. I would suggest a flat water filled copper tank coated with black carbon.

You can have the black carbon impinged into the copper. Use a small size particle, say around 1 micron or smaller for better surface area to capture the IR energy.