[pianotech] Protection from underfloor heating.

[Dean May]

Hey, its been 35 years since my engineering classes and my brain is getting
foggy. So I did a tiny bit of research to make sure I was on the right
track. It is important to distinguish between heat and temperature. 

 

>From Wikipedia (http://en.wikipedia.org/wiki/Heat): 

In  <http://en.wikipedia.org/wiki/Physics> physics and
<http://en.wikipedia.org/wiki/Chemistry> chemistry, heat is
<http://en.wikipedia.org/wiki/Energy> energy transferred from one body to
another by thermal interactions.
<http://en.wikipedia.org/wiki/Heat#cite_note-1> [1]
<http://en.wikipedia.org/wiki/Heat#cite_note-Kittel_and_Kroemer_1980-2> [2]
The transfer of energy can occur in a variety of ways, among them
<http://en.wikipedia.org/wiki/Heat_conduction> conduction,
<http://en.wikipedia.org/wiki/Heat#cite_note-3> [3] radiation,
<http://en.wikipedia.org/wiki/Heat#cite_note-4> [4] and
<http://en.wikipedia.org/wiki/Convective_heat_transfer> convection. Heat is
not a property of a system or body, but instead is always associated with a
process of some kind, and is synonymous with heat flow and heat transfer.

 

Heat is the measure of kinetic energy transfer between bodies, it is not a
measure of the kinetic energy of the molecules that you describe (even
though they use the same units of energy to describe them), unless we are
going to extract some of that kinetic energy and transfer it to another
body. For a given sum of kinetic energy of moving molecules, depending on
their mass, we can calculate the temperature. We could theoretically extract
the kinetic energy from those moving molecules in the form of heat and
transfer that energy to another body. Depending on the 2nd body's mass and
specific heat we could predict what its final temperature would be for a
given infusion of heat energy. 

 

We get heat from the sun, even though there are no molecules in space to
transfer it. Heat is pure energy transferred between bodies. Apply a given
amount of heat to low mass molecules, such as helium, and they will move
proportionally faster and thus be hotter in temperature than the same amount
of heat applied to a carbon molecule. 

 

At least that is my understanding, and I've been wrong before. 

 

Dean

Dean W May                (812) 235-5272 voice and text 

PianoRebuilders.com    (888) DEAN-MAY        

Terre Haute IN 47802

  _____  

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of David Boyce
Sent: Tuesday, December 11, 2012 2:27 PM
To: pianotech at ptg.org
Subject: Re: [pianotech] Protection from underfloor heating.

 

Dean, may I gently and respectfully suggest that you may be a bit mistaken
in your understanding of what heat is?  

Heat is a measure of total kinetic energy of molecules.  It is not a "thing"
in its own right.

Best regards,

David.

On 11/12/2012 19:00, pianotech-request at ptg.org wrote:

Radiant heat works not by warming the air, though there is some of that, but
by radiating the heat, duh. ;-) Objects with mass in view of the radiant
heat source absorb the heat and began to warm in temperature. The closer the
object to the source, the more heat is absorbed. A piano with lots of mass
sitting very close to the source will absorb lots of heat. While air, with
negligible mass, will not absorb much heat. So measuring the air's
temperature will not be any kind of indicator as to how much heat the piano
is getting.

 

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