Date: Fri, 6 Jul 2007 19:23:31 -0800
Reply-To: Troy <colorworks@GCI.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Troy <colorworks@GCI.NET>
Subject: Re: Heat exchanger for hot showers
Content-type: text/plain; format=flowed; charset=iso-8859-1; reply-type=response
> check the archives. no, really. ;)
> there was a guy in the early days of the vanagon list (can't recall his
> name right now) and he built a system under the rear seat of his camper.
> used the rear seat heater to provide the coolant ... which flowed through
> some copper coils inside a water tank. he had some sort of thermostat that
> shut off the flow of coolant to the coils if the water got too hot. he
> used it for the sink and had some sort of hookup to run a hose to the rear
> hatch (which held the shower curtain when the hatch was up).
>
> seems like the guy's name was dave something or other. had pictures and
> text on a web site.
>
> hope it helps. good luck!
> joel
>Thanks Joel:
Here's that link your referring to: http://www.syncro.org/HotWater.shtml
And then a response I sent to one other person who emailed me.
<<Yes, I have the link for that particular set up. That would require using
the onboard 13 gallon water, which is not something I was interested in
doing. The link I provided appears to be an "on demand" system, that is to
say as long as you have adequate water supply, (stream, lake, etc) you
could have endless hot water on demand. That's a lot different than heating
up the onboard water. The key is the type of heat exchanger. There are
propane units available such as the one I have (Coleman) and I believe there
is another company that puts out something called the zodiac, which works on
a similar principle. The Coleman actually works quite well on a picnic table
with a 5 gallon jug, but it is kind of large and bulky and takes up precious
space. Anyway, as I said I'm intrigued by the challenge more than anything
else. In my own experience, there seems to be plenty of places available
along the way to get a hot shower for cheap, and the Coleman works great at
picnic side for dishes, etc.>>
Another drawback to heating the onboard water is it promotes bacterial
growth. An "on demand" --heated as needed system--is what I was trying to
accomplish. That particular heat exchanger I provided the link for
(http://www.hotcampshowers.com/new51788.html) seems to do just that.
Basically, the criteria for this would be to figure out volume of water
needed (gallons per minute) versus the required rise in temperature.
Generally the greater the increase in temperature, the lower the flow. For
example heating water from 40° to 100° may only result in 1/2 gal. a minute
(GPM) versus going from 70° to 100°, which may result in 1 gallon a minute
or better. The Coleman I have is basically a 1 gallon per minute, but slows
down quite a bit if you try to crank the water temperature to say 160
degrees. I know just enough about this to get myself into trouble;) I was
hoping someone else might be more knowledgeable about this than I am. Sounds
like I will have to do a Google search and compare specs on the various heat
exchangers available out there.
If anyone else cares to chime in about this, I'm all ears.
Troy
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