Infrared underfloor heating - any good people out there to talk to?

[Benpointer]

48 minutes ago, SteamyTea said:

Yes and no.

Energy is transferred because it excites electrons to a higher orbital.  The higher energy electrons want to return to their original, more stable, state, when they do, they emit a photon.

That photon, which can be though of as a packet of pure energy i.e. massless, moves until it interacts with another electron, raising the electrons orbital, and then ceases to be (can be modelled as an 'at rest mass').

So while we like to think of thermal energy transfer as conduction, convection and radiation, it is really all radiation.

It gets a bit more complicated as there is intensity and frequency, and I have never found a simple to understand explanation.

The nearest I can get to, to explain intensity, is that depending on the material i.e. which elements, the strength of the bond between the electron(s) and the nucleus is different, so some materials take more, or less, energy to dislodge an electron i.e. different place on the electromagnetic spectrum.

Then it is the number of photons, the frequency, that pass or change the electrons in the element, that governs the rate of transfer, the power if you like.

There is no decent 'mechanical' description as it is a quantum problem, and as they say, 'if you understand quantum physics, you don't really understand quant physics'.

That's a great explanation Steamy, but I must take issue with one point: "So while we like to think of thermal energy transfer as conduction, convection and radiation, it is really all radiation."

 

Convection is surely a bit different because that is primarily the movement of material rather than heat.

Edited November 30 by Benpointer

[SteamyTea]

7 minutes ago, Benpointer said:

Convection is surely a bit different because that is primarily the movement of material rather than heat.

Yes, kind of, no.

Just moving something that is hot says nothing about power transfer and the use of that energy.

If, in the typical model, a wall mounted convection heater, moves some air up towards the ceiling, as it passes though heater, the air is warmed by radiative forces, then as it moves back into the room, it heats the room by radiative forces.

 

It does come down to how small you slice the problem up, and the usage of language.

Invection is a better term: introducing from an outside source.

 

I am still not happy with my explanation on intensity and frequency.

Edited November 30 by SteamyTea

[Temp]

20 hours ago, NMarshall said:

I have used it on walls and ceilings before

 

Is it really working as a direct IR system (heating people direct) or is it actually heating up the building and furniture then the air and that's why people feel warm?

 

How warm do rooms get? If your room air temperature is getting to say 21 -22c then it's no cheaper than any direct electric system and in the UK that's historically three times the cost of mains gas.

 

I suppose if it's small and well insulated the absolute running cost would be small whatever system you use.

 

[saveasteading]

28 minutes ago, Temp said:

if it's small and well insulated the absolute running cost would be small whatever system you use.

If the room is very small and very well insulated, body heat will do it at no cost. Gradually peeling off jumpers until dying of asphyxia or overheating.

Could we call that IR heating?

[JohnMo]

15 minutes ago, saveasteading said:

If the room is very small and very well insulated, body heat will do it at no cost. Gradually peeling off jumpers until dying of asphyxia or overheating.

Could we call that IR heating?

Our office (designated as a store on the plans), is small, no windows, no heating, the hall it's attached too has no real heating just pipes to rooms passing through. I have extract terminal in there, so it's pulling air from elsewhere continuously. Within 10 mins of being in there it's nudging 21. In the summer it's the coolest room in the house.

 

 

[Benpointer]

12 hours ago, SteamyTea said:

Yes, kind of, no.

Just moving something that is hot says nothing about power transfer and the use of that energy.

If, in the typical model, a wall mounted convection heater, moves some air up towards the ceiling, as it passes though heater, the air is warmed by radiative forces, then as it moves back into the room, it heats the room by radiative forces.

 

It does come down to how small you slice the problem up, and the usage of language.

Invection is a better term: introducing from an outside source.

 

I am still not happy with my explanation on intensity and frequency.

The oil-fired hot water system radiators in the house we are currently renting are heating air which rapidly radiates half its heat out through the windows conveniently placed directly above the rads.  

 

Why do people do that?

[ReedRichards]

On 30/11/2024 at 07:43, SteamyTea said:

Energy is transferred because it excites electrons to a higher orbital.

 

You are thinking of radiative energy and in the context of atoms and small molecules.  But the difference between cold air and warm air is that the molecules have more kinetic energy and are moving around faster.  The molecules with more kinetic energy interact with your body by taking away less extra kinetic energy when the bounce off you so you don't cool so fast, assuming that the air temperature is less than your body temperature.  

[SteamyTea]

1 hour ago, ReedRichards said:

radiative energy

My point is that it is all radiative energy.

[ReedRichards]

12 hours ago, SteamyTea said:

My point is that it is all radiative energy.

 

And my point is that you are wrong.