[Stoves] Question regarding calculations

ajheggie at gmail.com ajheggie at gmail.com
Sun Oct 4 15:18:26 MDT 2015


[Default] On Tue, 29 Sep 2015 20:17:29 -0700,Frank Shields
<franke at cruzio.com> wrote:

>Greetings Stovers, 
>
>Wanting to know if it takes less energy to keep water boiling at 80 deg. C at 1500 meters than at sea level?

Frank I've waited before ploughing in because I couldn't understand
the reasoning behind your question.

The thing is at 1500 metres above sea level the pressure is still 96%
of pressure at sea level, so to boil water you have to raise the
temperature of water until it's vapour pressure equals the ambient air
pressure, and that is at 98.6C
>
>Also; It take 4.186 j/g/deg.C to raise water from 20c to 80c at sea level. But is it the same at 1500 meters? or is it less than 4.186?

From Prof Lloyd's post the specific heat of water varies with
temperature and is probably thus not variable with pressure.

So my view would be to keep water at 80C at 1500 metres asl in a
saucepan with tight fitting lid, so no vapour escapes would be the
same power as at the same ambient temperature as at sea level.

AJH



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