thought for the day which is better

energysavingexp

thought for the day which is better:

which is more Efficient a bare metal radiator. one sprayed sliver or one sprayed black
the reason for the question is will the silver or black paint act as an insulator there for not emitting as much heat.
or will the silver one emit more as silver reflects heat
or the black one which absorbs heat?

ps: is it true you cannot see light but you can only see an illuminated reflection of an object as light travels through space its only the refletion off dust particals or objects that you see and not the light its self?

DUTR

energysavingexp wrote: »

thought for the day which is better:

which is more Efficient a bare metal radiator. one sprayed sliver or one sprayed black
the reason for the question is will the silver or black paint act as an insulator there for not emitting as much heat.
or will the silver one emit more as silver reflects heat
or the black one which absorbs heat?

ps: is it true you cannot see light but you can only see an illuminated reflection of an object as light travels through space its only the refletion off dust particals or objects that you see and not the light its self?

So scientifically why would the colours reflect heat as opposed to reflecting light?

energysavingexp

DUTR wrote: »

So scientifically why would the colours reflect heat as opposed to reflecting light?

this is what i want to know.
if it dos'nt reflect heat why do people fit silver foil behind rads yes some colours will reflect more light than others some will absorb heat/light but will it make a difference to the output?

DUTR

energysavingexp wrote: »

this is what i want to know.
if it dos'nt reflect heat why do people fit silver foil behind rads yes some colours will reflect more light than others some will absorb heat/light but will it make a difference to the output?

Yes some folk do put heat reflectors behind some rads on exterior walls , which don't affect the output but will affect the efficiency in a positve way, after all you want to heat the room not the wall.

energysavingexp

DUTR wrote: »

So scientifically why would the colours reflect heat as opposed to reflecting light?

it must because you dont see black foil fitted behind a rad only silver so silver must reflect more heat than black
not that much light behind a rad to reflect

DUTR

energysavingexp wrote: »

it must because you dont see black foil fitted behind a rad only silver so silver must reflect more heat than black
not that much light behind a rad to reflect

And no black insulating tiles on the space shuttle

energysavingexp

DUTR wrote: »

And no black insulating tiles on the space shuttle

It is required that both black and white tiles are used on the Space Shuttle in order to control the temperature of the vehicle while in orbit.

• White tiles (known as LRSI) are used mainly on the upper surface and have higher thermal reflectivity. These are therefore pointed towards the sun in order to minimize solar gain.

• Black tiles (known as HRSI) are optimized for maximum emissivity, which means they lose heat faster than white tiles. This property is required in order to maximise heat rejection during re-entry.

DUTR

energysavingexp wrote: »

It is required that both black and white tiles are used on the Space Shuttle in order to control the temperature of the vehicle while in orbit.

• White tiles (known as LRSI) are used mainly on the upper surface and have higher thermal reflectivity. These are therefore pointed towards the sun in order to minimize solar gain.

• Black tiles (known as HRSI) are optimized for maximum emissivity, which means they lose heat faster than white tiles. This property is required in order to maximise heat rejection during re-entry.

I stand corrected

victor2

energysavingexp wrote: »

ps: is it true you cannot see light but you can only see an illuminated reflection of an object as light travels through space its only the refletion off dust particals or objects that you see and not the light its self?

Boy, you guys are getting deep.

However, on the lighter question....
Surely the reflection is light, so you can see light - so long as it is at a visible (to us) frequency. And we still see light from stars, which has travelled at least part of its journey through the vacuum of space, where there is no dust to reflect off.

SYNERGY

energysavingexp wrote: »

It is required that both black and white tiles are used on the Space Shuttle in order to control the temperature of the vehicle while in orbit.

• White tiles (known as LRSI) are used mainly on the upper surface and have higher thermal reflectivity. These are therefore pointed towards the sun in order to minimize solar gain.

• Black tiles (known as HRSI) are optimized for maximum emissivity, which means they lose heat faster than white tiles. This property is required in order to maximise heat rejection during re-entry.

Black tiles (known as HRSI) are optimized for maximum emissivity, which means they lose heat faster than white tiles.

There's your answer.

Now look on Ebay for some HRSI tile to stick on all your radiators. :think: :idea: :rotfl:

There must be loads spare now the Shuttle program has ended.

energysavingexp

victor2 wrote: »

Boy, you guys are getting deep.

However, on the lighter question....
Surely the reflection is light, so you can see light - so long as it is at a visible (to us) frequency. And we still see light from stars, which has travelled at least part of its journey through the vacuum of space, where there is no dust to reflect off.

yes but if you shine a light into space you cannot see the beam you can only see the reflection off an object/partical
in space you dont see the beam of light from the stars do you. you only see the object :rotfl: