Underfloor Heating with Engineered Wood Flooring

[bernardgreen]

Of course Google Warriors are always best ignored!!!

But people with 30 years lectureing in physics and thermodynamics may have better appreciation of the laws of thermodynamics than the average or even most advanced plumber.

The first statement of the 2nd law of thermodynamics - heat flows spontaneously from a hot to a cold body

where as other accademic sources share the opinion that the first statement of the second law is

The second law of thermodynamics states that the total entropy of an isolated system can only increase over time

the important word that is often overlooked is the word isolated


EDIT from http://theory.uwinnipeg.ca/mod_tech/node78.html
2nd Law of Thermodynamics
The total energy, including heat, in a ( closed ) system is conserved

Aof course all this it irrelevent as UFH is not a closed or isolated system

 

[Roger928]

UFH heats the walls first then it travels down from the ceiling. Its called inverted radiovection.

 

[PullerGas]

UFH heats the walls first then it travels down from the ceiling. Its called inverted radiovection.

Eh??!! UFH is mainly radiant heat, it minimises the radiant heat lost by the human body. A radiator will mainly produce convected heat, which will heat the ceiling first & as the air temperature drops it'll fall & heat you.

 

[PullerGas]

But people with 30 years lectureing in physics and thermodynamics may have better appreciation of the laws of thermodynamics than the average or even most advanced plumber.



where as other accademic sources share the opinion that the first statement of the second law is



the important word that is often overlooked is the word isolated


EDIT from http://theory.uwinnipeg.ca/mod_tech/node78.html
2nd Law of Thermodynamics
The total energy, including heat, in a ( closed ) system is conserved

Aof course all this it irrelevent as UFH is not a closed or isolated system

Granted my interest in Fizics is limited to it's relivence to my trade - as with Cemmestray. Couldn't give a shyte about academic debate.

 

[Agile]

Eh??!! UFH is mainly radiant heat, it minimises the radiant heat lost by the human body.

I always thought it was conducted heat!

You take off your shoes and socks and the floor conducts the heat directly into your feet! Saves wasting heat by needing to heat the room itself. It is called direct heating!

 

[Doggit]

I always thought it was conducted heat!

It's radiant heat, but only to a comfortable level, ie about the head. It will of course be conducted into your feet where you stand on it, but that wouldn't wok if you were on a stool, so it has to be radiant. A radiator produces both radiant and convected heat, in that it'll warm the air near it, that then rises, but it'll also radiate heat outwards to warm the room. But as Puller says, there is also a degree of the heated air the falling back, and going through the heating process again.

But I think Roger has the best appreication of how it all works.

 

[PullerGas]

It's radiant heat, but only to a comfortable level, ie about the head. It will of course be conducted into your feet where you stand on it, but that wouldn't wok of you were on a stool, so it has to be radiant. A radiator produces both radiant and convected heat, in that it'll warm the air near it, that then rises, but it'll also radiate heat outwards to warm the room. But as Puller says, there is also a degree of the heated air the falling back, and going through the heating process again.

But I think Roger has the best appreication of how it all works.

No, Roger is saying it's mainly convected heat.

 

[PullerGas]

You've gotta luv this forum, awash with poorly informed, inexperienced & Google Warriors!!

 

[bernardgreen]

Heating by radiation only works if the item to be heated is at a lower temperature than the source of radiant heat.
Body temperature 37°C ,
What temperature is the surface of the floor when heated by UFH ?
Why do some people in houses heated by UFH always ( have to ) wear slippers in the house ?

 

[Dan Robinson]

You're not Heating the human body are you.

You're heating the air in the room.

 

[Dan Robinson]

You've gotta luv this forum, awash with poorly informed, inexperienced & Google Warriors!!

It's almost painful sometimes.

 

[bernardgreen]

You're heating the air in the room.

UFH is mainly radiant heat, it minimises the radiant heat lost by the human body. A radiator will mainly produce convected heat, which will heat the ceiling first & as the air temperature drops it'll fall & heat you.

Can you heat air by radiated heat, if you can then how efficient is the process ?

Exclude the effect of walls heated by radiation giving up that heat to the air by conduction / convection
[

 

[Dan Robinson]

Can you heat air by radiated heat

Obvs.

If you can then how efficient is the process ?

I know and care not.

 

[bernardgreen]

Obvs.

? Hint, if radiation heats air then how does radiant heat reach a person.

Some molecules such as CO2 (*) and water vapour will absorb radiated thermal energy and heat themselves and thus heat the other molecules around them. Hence the "efficiency" of heating air in a room by radiation depends on the levels of humidity and carbon dioxide in the room.

(*) CO2 increases global warming by absorbing radiated heat that would otherwise pass through the atmosphere and be lost to space.

 

[bernardgreen]

I know and care not.

As a designer of heating systems ? ? ?