Date:         Thu, 22 Dec 2016 08:58:29 -0800
Reply-To:     Alistair Bell <albell@SHAW.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Alistair Bell <albell@SHAW.CA>
Subject:      Re: More Mr heater..
In-Reply-To:  <E7E488C6-D519-4A06-AAEB-638DA973DA90@gmail.com>
Content-Type: text/plain; charset=us-ascii

It's not that dons perceptions are invalid. It's rather that burning propane does produce water ( in the environment we live in anyway) and the amount of water produced is predictable. Predictable with some certainty and is not fake news.

If that water vapour is noticeable or not, is another issue. I worked it out as almost 3 cups of water for every pound of propane burned.  If that seems like a lot or not, is up to you :-)

I think I balanced the equations and made reasonable assumptions in the following.
For a one pounder, and lets make assumption that no CO is produced, ie the heater is working perfectly, and that there are 16 oz to the lb, or 454 g.

combustion equation:

C3H8 + 5O2 -----> 3 CO2 + 4H2O

i.e. for every mole of propane burned, we get 4 moles of water.

molecular weight of propane = 44 g/mol

moles per 1 lb bottle = 454/44 = 10.3 moles

therefore burning the entire bottle would produce 4(10.3) = 41.2 moles of water

molecular weight of water = 18 g/mole

therefore 18(41.2) = 741.6 g of water produced.

almost 3 cups of water into the van when one pound of propane burned.


alistair



> On Dec 22, 2016, at 8:42 AM, Patrick Spragge <spraggepat@gmail.com> wrote:

> 
> Perhaps I'll comment on these 2 messages on Friday.  
> 
> 
> 
> Patrick Spragge
> 
>> On Dec 22, 2016, at 8:27 AM, Alistair Bell <albell@SHAW.CA> wrote:
>> 
>> If you look at the chemistry of propane combustion and you spend some time to understand it, then you will see how much water vapour is produced per unit of propane burned.
>> 
>> It's is not fake news or exageraration. It's basic science. As unpopular as science is these days, it still rules.
>> 
>> 
>> Alistair
>> 
>>> On Dec 22, 2016, at 8:20 AM, Don Hanson <dhanson928@GMAIL.COM> wrote:
>>> 
>>> The word was the Mr. Heater, and others, catalytic propane, create a lot of
>>> water vapour in a Vanagon.  That seems to be fake news, or perhaps an
>>> exaggeration.
>>> I've been running two now, in the wet southwest desert, one in a camp
>>> trailer and one in the "annex" (my Vanagon)   Fairly humid here now,and no
>>> interior moisture problem at all.  Perhaps the catalytic combustion is
>>> dryer than people have said..
>>>  Now when I ignite the Westie cook top, the Vanagon steams right up,
>>> immediately.
>>>   So there you go, a report of one family's (two humans and three large
>>> Chesepeake dogs, full timing with two Mr. Heaters as our comfort heat)