And yet more and less about: The chilling truth about cold horsepower

["S. Hieber" <shieber at yahoo_com>]

Steve point to  COP.  Good pointing, I think.  Steve said:

"There is another term you might want to consider called
the "Coefficient of Performance" (or COP).  COP is used as
a measure of efficiency of a refrigeration system.  It is
defined as the cooling ability of the system over the power
input to the system.  Because refrigerators, chillers, and
air conditioners only move heat from one location to
another it is possible to move an amount of thermal energy
that is greater than the amount of work the pump or motor
puts into the system.  It turns out that for air
conditioners, typical values for the COP are somewhere
around 2-3 or so (as memory serves).  "

I have come across this and the formula and test procedures
for determining the value.  This comes closer to resolving
the conumdrum than anything else so far.  In essence, this
says that moving a BTU/hr worth of energy from one set of
matter to another is not the same as using it -- Or perhaps
that a cooling btu is not the same as a regular btu.  I can
imagine that picking up a block of ice and walking it to
the next room takes moves more ice that the energy of
carrying and walking consumes.  But I wonder if that's a
good analogy -- in any case where water is being cooled, or
ice melted, or wood burned or lights lit, isn't the energy
being moved from one location to another?  If that cooling
a gallon of water one degree per time period is equivalent
to one BTU, why is cooling capacity a positive multiple of
the energy input BTU.

If the ice block analogy is good, then an air conditoner's
situation is like blowing hot air from one room to another
and scuking in cold air in its place -- and even an
electric fan has a BTU rating higher than it's energy input
rating, because with a few wafts of its blade it can push a
hunk of very hot air over there and replace it with a hunk
of cool air from just behind the blade here.  

Scott H.

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