Re: low power efficiency

[Carefreeland@aol.com]

In a message dated 3/8/02 5:24:05 PM Eastern Standard Time, adkarve@pn2.vsnl.net.in writes:

  >Reply in text

> Subj:Re: low power efficiency 
> Date:3/8/02 5:24:05 PM Eastern Standard Time
> From:adkarve@pn2.vsnl.net.in
> To:tami.bond@noaa.gov
> CC:stoves@crest.org
> Sent from the Internet 
>
>
>
> Dear Ms Bond,
> the discussion so far shows that the boiling and evaporation test that we
> have so far been conducting, gives us just that, i.e. efficiency of boiling
> and evaporating water. It does not really reflect the cooking efficiency of
> a stove, which is operated in many different ways. One of the standard
> procedures in cooking anything is to bring the water to a boil, then cover
> the pot, reduce the flame and just allow the pot to simmer.  Experience with
> solar cookers and also with the hot box show, that one does not even require
> a temperature of 100 degrees Celsius for cooking.  With the pot just
> simmering, there would be very little evaporation, and, as you have rightly
> mentioned, the efficiency of the stove would be near zero, and yet the
> cooking process would be completed with very little fuel. Therefore, the
> test that has been recommended by the Ministry of Non-Conventional Energy
> Sources, Government of India,  requires the tester to keep a series of
> standard pots ready, filled with a certain constant amount of water. The pot
> is covered with a lid. As soon as water in one pot reaches a certain
> temperature, say 90 or 95 degrees, one takes it down and sets the next pot
> on the stove.  In this way, only the rise in temperature of the water is
> taken into account and not the amount of water evaporated. One has to make
> some allowance for the conductivity of the metal of the pot, because heat
> would be lost through the surface of the pot.
> A.D.Karve

   > Along this same lines a tester could be constructed consisting of a larger tank of water at a pre-determined temperature.  The water could be circulated through a sealed test pot with a closed lid by gravity to another pot over time.  The temperature and volume of the lower tank could then be measured. 
       Along these same lines, a single tank of known volume could be plumbed to a sealed pot with a recirculating pump. At the end of the experiment the pot would be drained into the tank and the temperature of the tank measured. 
       This is a method of measuring solar heat storage so I'm sure it would work fine with a stove. 
       Daniel  Dimiduk.