mgs
[Top] [All Lists]

Re: Cool concepts

To: William Eastman <william.eastman@medtronic.com>
Subject: Re: Cool concepts
From: "W. R. Gibbons" <gibbons@northpole.med.uvm.edu>
Date: Fri, 21 Mar 1997 16:59:25 -0500 (EST)
On Fri, 21 Mar 1997, William Eastman wrote:

> Since Ray is sick of this topic, let me take a shot at it.
> 
> Try or think about this experiment.  Drop an ice cube into a glass of hot
> water.  Do the same in a second glass.  Stir one glass and let the other
> one just sit there.  The ice cube will melt much faster in the stirred
> glass because the warm water moves by the cold surface faster.  The same
> concept applies in your car.  The faster the fluid flows past the exchange
> surface, the more energy is exchanged.  

I have to admit I once fell for the going through the radiator too fast
line of reasoning.  I had a house with hot water heat (for you CA folk,
that is a furnace that heats water, which is then circulated by a pump
through radiators to heat the house).  My furnace worked, but was tired,
so I spent $3500 for a new pump and furnace.

To my surprise, the new furnace would not keep the house warm.  My first
thought, since the temperature of the water was the same and the pump was
new, was that perhaps the new pump pumped the water so fast it did not
have time to give off its heat to the house.  I actually went down and
closed the valve a bit in the circuit, to slow the water down.  It worked
worse. 

Then I began to think seriously about all this, and concluded that the 
faster the water went, the better.  So I have cogitated on this, and even 
done an experiment of sorts.

(Turned out the thermometer on the new furnace was wrong, and the water 
going through the radiators was 20 degrees less warm than the water in the 
old furnace.)

   Ray Gibbons  Dept. of Molecular Physiology & Biophysics
                Univ. of Vermont College of Medicine, Burlington, VT
                gibbons@northpole.med.uvm.edu  (802) 656-8910


<Prev in Thread] Current Thread [Next in Thread>