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Re: The chilling truth about cold horsepower



From: "S. Hieber" <shieber at yahoo_com>


Thank you Jerry and Bill for taking the time to look into
this problem of mine more deeply.


Unfortunately, even as I read through your thoughtful
replies, the problem is not resolved.  A BTU/hr. is a unit
of Power, as are HP and Tons Refrigeration.  And with
airconditoners, the rated BTU/hr of cooling capacity is
much *greater* than the rated BTU/hr of energy input.  You
can leave HP out of it and just use the watts rating for
energy input and the BTU/hr rating for cooling capacity.


For example a 610 watt air conditioner is rated for 6000
BTU/hr cooling capacity.  610 watts=2077 BTU/hr yields 6000
BTU/hr cooling capacity.  Does this not seem odd?


There is something I am obviously missing here, but I'll be
darned if I can figure it out, so far. I'm checking this
further.  I'll let you know what I find out.


If you are converting electricity into heat, as with an electrical heater, then the energy put in must equal the energy out. But when you are cooling, you are not doing the opposite. Instead, you are transporting heat out of the room, not producing "cold". When I was a graduate student I had to rear my research animals (preying mantids) in an unheated room, and I had to rig up my own system of temperature control. I had two thermostats, one controlling a 15 ampere heater and another one controlling a 10 ampere air conditioner window unit. I adjusted the thermostats to be quite close in their settings so that the temperature was held within a narrow range. I always worried what would happen if I adjusted too closely and the heater started fighting the air conditioner. I figured that the heater, being of greater ampereage , would win out over the air conditioner. One day it happened, and I was surprised to find that the air conditioner was prevailing, fortunately for my mantids. The way I finally figured it was that the air conditioner was transporting heat out of the room, rather than making "cold" in some process equivalent to a heater making heat.
--
Paul Krombholz in steamy central Mississippi