Fridge Covers, they ARE arse about

why not do a test?? check temp with cover as is. then wrap all in alfoil - over the cover - and check temp. maybe better to just not leave fridge in sun if possible

Hi Jim

It makes little difference particularly as the cover gets older
and there is a specific saftey reason for the dull surface being on the outside.

That reason is that it doesn't cause a dangerous reflection into
drivers eyes.
For the same reason building sisalation is now dull on the outside(and also builders can get sunburn from it).

As for the heat reflection , it also works on heat being emitted from a surface,including the inside surface.
The emission is proportional to the smoothness of the surface and over time an outside surface gets roughened up causing a loss of efficentcy.

The fact that the air is hot between the inner layers is not ideal but its also not as bad as it seems because the warm air has little thermal mass as doesn't pass the heat thru readily.

Jim,

I agree with you, never been able to work that one out myself. Its like roof insulation, shiny side up - reflects the heat away, dark side down - absorbs heat form the roof space.

Foil doesn't keep it colder at night, it still reflects any trapped heat back to the fridge and stops it escaping for longer. Same way a space blanket works.

Maybe its just a fashion thing.

Matt.

The silver side can't "block cold in". Heat always moves from hot to cold, so therefore the shiny side should be out, but as heat is simply energy and their are different types, silver is only effective in reflecting some types of heat ie, sunrays. As far as I can see, silver side only doing its thing if the fridge and cover are in direct sunlight. In the back of a covered vehicle where the heat is coming from air temp, the silver will heat up as much as any other material. What matters then is the insulating factor of the layers, that is, the rate at which heat can through the layers. If it is hotter outside the fridge than in, heat will continue to move through the layers (including the fridge case) until the temp inside of the fridge balances with the temp outside. The thicker and higher insulation factor of the layers, the slower heat can move through to do its balancing trick. The fridge motor removes heat from inside the fridge and dumps it into the air outside the fridge.

And to get an even better efficiency you could paint your fridge black - as long as the surface is not in direct sunlight.

I can see that having the silver side out might help reflect the sun's rays and heat energy away from the fridge but there is one possible issue. I think I would need a welding helmet to get anywhere near it to get a beer out on a bright sunny day!

Cheers
Muddy

Hello Jim and the Forum,

I use a refridgerated Transit van for work, drive long distance with fridge on 2-3 degrees. The rear fridge section is fully insulated, and in my opinion well insulated, it has to be.
When I stop, the outside of the vehicle (the fridge part) is cool to touch, sides, roof, doors, all cool, even on a very hot day like 40 degrees.

So if we consider this to be a big car fridge, then if a cover was put on it, the cover would have the reflective silver stuff on the inside to reflect to coolness back in, and that is probably why our car fridges have it on the inside. Keeping coolness in rather than the ambient temperature out.

The idea of covering with a reflective windscreen cover works too because it does minimise the ambient heat entering the cabinet, as does parking it in the shade, covering with a blanket, or operating it at night or overcast days, it does make a difference.

My point is maybe the covers are designed to keep coolness in rather than heat out.

Remember the heat from within the cabinet is taken out by the system and pumped out into the car via the vent in the compressor containment. If your car is not able to let this heat out it is then adding to the ambient temperature around the fridge.

Cheers

Hey Jim.....
Pick up a piece of foil.........look at it.......... and then turn it over.........SPOOKY HEY..........Same $hiit both sides????????

Theory is........whats out stays out, whats in stays in.....( a little longer)

Cheers

explain a survival blanket then, silver stuff on the outside. ????

Shiney in shiney out why is a car radiator painted black then

Greenant

trailblaza.....

No bag required!

Simple.

Cheers

Brian

G/day Jim,Strewth,you sure know how to get a thread going,It must be those old farts yer camping with.Thanks again for your help the other day.I hope you`re making a quid. Regards Keith C

If you have an object hotter than its surroundings and you want it to cool down, paint it black, it radiates heat better than silver does.

If you have an object cooler than its surroundings and you want to keep it cool, paint it silver, it will reflect the surrounding heat away.

This only applies to air interfaces because its about radiation. Two surfaces in contact with each other are controlled by conduction, not radiation.

Why is the reflective side of sarking on the inside when it is wrapped around a house?

If a single reflective surface is used alone and faces an open space, it is called a radiant barrier. Which is a reflective insulation.

When it faces inward it is thermal resistance insulation measured as a R-value which is a resistance to heat flow. The greater the R-value the better it insulates.