Dear Crispin,
Message: 2
Date: Mon, 30 Jan 2012 10:58:19 -0500
From: "Crispin Pemberton-Pigott" <[email protected]>
To: <[email protected]>, "'Discussion of biomass cooking stoves'"
<[email protected]>
Subject: Re: [Stoves] oxygen percentage in air ( same altitude ) and
wood stove performance
Message-ID: <[email protected]>
Content-Type: text/plain; charset="us-ascii"
Dear Rajan
It is not possible for the O2 level to be significantly different, but
there
is a chance that the humidity of the air is different.
Humidity could be different.
Assuming you have fuel with the same moisture content in both places, the
absolute humidity (mass of water per cubic metre) can make a small
difference. I have noted this when testing 'racing stoves' a few years
ago.
When it is really humid the performance deteriorated very noticeably.
Perhaps I should first ask, what is the performance difference you have
noted?
The flame was looking much brighter/better/hot. No measurements taken.
Are you taking a fuel sample and using it at both locations?
Yes.
It is
more likely to be the fuel.
No.
Regards,
Rajan
From: [email protected]
[mailto:[email protected]] On Behalf Of
[email protected]
Sent: Monday, January 30, 2012 10:10 AM
To: [email protected]
Subject: [Stoves] oxygen percentage in air ( same altitude ) and wood
stove
performance
Dear All,
What would be the difference we can expect in the percentage of oxygen in
the urban and rural air ( altitude remaining the same ) ?
I am asking this question since I found the same wood stove with the same
fuelwood performed better in a rural area compared to an urban area (
altitude being sea level at both places ). I am not able to find any
reason
except a possible difference in the oxygen percentage in the air at the
two
places.
Has anybody else also experienced something similar ? Or is it just my
illusion ?
Hope to get some clarification from somebody.
Regards,
Rajan
------------------------------
Dear AJH,
Message: 3
Date: Mon, 30 Jan 2012 16:20:01 +0000
From: [email protected]
To: Discussion of biomass cooking stoves
<[email protected]>
Subject: Re: [Stoves] oxygen percentage in air ( same altitude ) and
wood stove performance
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
On Monday 30 January 2012 15:09:58 [email protected] wrote:
Dear All,
What would be the difference we can expect in the percentage of oxygen
in the urban and rural air ( altitude remaining the same ) ?
Interesting question Rajan, my first guess was that because of wind and
rates of diffusion any concentrations of pollutants and CO2 would be
rapidly levelled off but I see a 2008 news report that polluted city air
can drop to 15% O2 compared with the normal 21% we expect to see.
This is the point of my doubt.
Although air pressure drops with altitude it should not affect the gas
volume ratios.
Volume ratios are not affected. But air density will be differrent.
I am asking this question since I found the same wood stove with the
same fuelwood performed better in a rural area compared to an urban
area ( altitude being sea level at both places ). I am not able to find
any reason except a possible difference in the oxygen percentage in the
air at the two places.
Have you considered change in humidity affecting the equilibrium moisture
content of the wood?
I have not considered the humidity. But it was the same wood sample.
AJH
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