Re: The chilling truth about cold horsepower - Or fun with numbers

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

Jerry Smith tracked down a reference source with e 12,000
BTU/hr= 1 hp = 1 ton Refrigeration.  And he found out a
curious thing.

> I checked my 1965 World Book Encyclopedia and found the
> following 
> information in the article on Air Conditioning. Air
> conditioners are rated 
> in three ways, by B.T.U.'s, Tons of Refrigeration, or by
> Horsepower. One Ton 
> of Refrigeration removes the amount of heat needed to
> melt one ton of ice in 
> 24 hours. One Ton of Refrigeration can remove 12,000
> B.T.U.'s of heat in one 
> hour. The B.T.U. is the amount of heat needed to raise 1
> lb. of pure water 1 
> degree F. 

Ah yes, Tons Refrigeration is a standardised unit of power,
as are BTU/hr and HP.  So mathematics *ought* to be
applicable:  If 1 hp = 2450 btu. hr and = 1 ton
Refrigeration, which in trun = 12,000 btu/hr, 
then 2450 btu/hr =2450 btu/hr !  
I reviewed the axioms and theorems in the methods of
mathematics I'm using and, although not a mathematician by
any stretch of the wildest imagine, feel reasonbably
certain that something is wrong with the above.  

> An air conditioner rated at 12,000 B.T.U./hr.
> can remove the heat 
> needed to raise 12,000 lbs. of water 1 degree F.
> Horsepower is the amount of 
> power needed to run the refrigeration equipment that
> cools the air.


So 1 hp of input (745.7 watts or 2450 BTU/hr) can cause a
chiller to have 12,000 BTU/hr of output (to absorb and
disperse 12,000 BTU/hr)?  Or to put it anothger way, 2450
BTU/hr can provide enough kinetic energy to water molecules
to move them from solid to liquid temperature and do so
12,000 btu/hr worth.  Does it not take at least 1 BTU/hr
(probably more) to absorb and disperse 1 BTU/hr? 
 
I new these dangnab electronic calculators would prove
unreliable someday! Where's my old slide rule?

Here are some measuremetns for an actual refrig unit, the
units in "*" marks are measurements and the others are
conversions:

Input minimum=*5,820 watts* = 7.8 Tons Ref. = 93.7 BTU/hr

Output avg.=2983 watts = *4 Tons Ref.* = *48,000 BTU/hr./ 

That makes sense, it takes more to make less (entropy
prevails, whether I like it or not). 

But the aquatic chillers seem to be about 600% energy
efficient.

> 
> I am not an expert at all on refrigeration, but answering
> this question has 
> helped me with understanding what Tons of Refrigeration
> means as I couldn't 
> understand why such a term was used. Thanks Scott for the
> question and 
> provoking me to search it out.
> 
> Jerry

You're satisfied? You're certainly welcome.  But now I just
wish *I* knew what the heck what going on.  This still
seems to me to be as whacky as Eheim's pump ratings.

Scott H.

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