Date: Sun, 26 Nov 2006 07:45:01 -0800
Reply-To: Mike Rouby <mikerouby@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Rouby <mikerouby@YAHOO.COM>
Subject: Re: Aircooled? - building my own interior heating system!
In-Reply-To: <F35A231E-FD9A-45FF-9A6A-1F2D009993C0@pottsfamily.ca>
Content-Type: text/plain; charset=iso-8859-1
Thanks Greg. In light of some of these discouraging facts, I will "borrow" the most expensive parts from my Mercedes and buy an additional $50 worth of parts and test my theory out. Worse comes to worse, I can use it as a science project for my kids going to school :)
I have recently bought a Mr. Heater (4000 BTU/ 9000 BTU) which will be all I need if I decide to camp "off the grid" (6 hrs 4000 btu/ 3 hrs 9000 btu per 1lb. gas cylinder) providing I crack a window open. My one and only camping trip in the Vanagon so far at a campsite has proven the combination of electric blanket (for the kids in the upper bunk), sleeping bags for all, and 1500watt electric ambient heater (set at a low temp. regulated setting) was all that was needed in 40 degree weather.
My indoor thermometer was telling me it was 72-75 degs inside the Westy, while 42-51 degs outside. Quite comfortable I must say.
I definately recommend the Mr. Heater (under $100) for any Vanagon camper and a good electric heater for shore-power camping. A Propex, Plat Cat or Espar, etc. is not really needed, though all good additions for cold-weather camping.
I'm a pop-up camper who graduated to a Westfalia, so while many people see it as a nice VW bus with a multiple-use, I see it as a unique Class B RV that's fun for the whole family!
Greg Potts <greg@POTTSFAMILY.CA> wrote: Hi Mike,
A gas heater or propane/gasoline/diesel furnace emits thousands of
watts from combustion. In order to get that much energy out of a
liquid you have to be able put it in to the liquid first. How the
energy is distributed is irrelevant: if you are transferring the heat
from liquid to the cab of the van you have top be able to put it back
into the liquid or the rad soon goes cold and the van goes cold.
So lets look at the wattage and voltage requirements. Veggie oil
heaters like this one:
http://www.kenneke.com/veggie.html are rated at 10 amps of 12V. Watts
= Volts X Amps. That electrical draw translates to provide 120 watts
of heat. Less if there are thermal inefficiencies in the heater
design. Are you going to heat the entire van with the equivalent of
two 60W light bulbs? I don't think so. If you want to generate 1000W
of heat you are going to need to pull about 80 Amps out of your
battery, and a Vanagon alternator isn't rated for that much extra
load. I suppose you could fit a spare alternator into an AC bracket
but that's getting complicated and your engine really doesn't need to
give up any additional HP.
Honestly (And since all the above was honest, so why am I singling
out this particular paragraph? I don't know, it's just a figure of
speech I guess.): You'd be warmer in the long run spending that $200
replacing your heater boxes or buying espar or southwind furnaces at
swap meets. or buy a black cat heater and keep a window cracked. Or
buy some heated clothing, or a nice warm hat and mitts.
Happy Trails,
Greg Potts
1973/74/75/77/79 Westfakia "Bob the Tomato"
www.pottsfamily.ca/westfakia
www.busesofthecorn.com
On 25-Nov-06, at 3:33 PM, Mike Rouby wrote:
> Actually, electric vehicles heat the interior using 'waste' heat
> transfer usually. The heat off the electric process/motors is
> recycled to heat the interior.
>
> However, I am quite convinced that this may work - enough to dump
> $200 (total cost) into the project. If successful, I will fit it
> into the Vanagon as a permanent device. Initially, I will bench
> test the entire assembly on a table.
>
> Thinking out loud, I may use vegetable oil instead of water/
> antifreeze (similar concept to an oil-filled radiator) as a
> conductor. Only issue with that, is that it may take some time to
> warm up.
>
> Wil Haslup wrote: Greg Potts wrote:
>> Hi Mike,
>
>> It's not going to work. You can't extract enough energy from a 12V
>> battery to heat 180 cubic feet of Vanagon interior. Your alternator
>> could not keep up with the draw, either. It's basic physics, and the
>> question has come up on the aircooled list every fall since the lists
>> started. If it was practical, automotive engineers would have
>> adopted electrical heating a long time ago.
>
>> There are tiny little 12V hairdryers that are popular for defrosting
>> bus windshields, but they don't supply enough heat to warm the
>> interior of a bug.
>
>> The best approach for electric heat in a vehicle is to wear heated
>> clothing. That might not be as convenient, but it will work.
>> http://cozywinters.com/heated-clothing/?
>> source=go&gclid=CMSk6eXm4ogCFSLrPgodnGpapQ
>
> While my original post mentioned my questions of the amount of amps
> being drawn being too much, I'm not certain that would make this
> scheme
> unworkable.
>
> ---
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