Date: Thu, 16 Aug 2007 17:38:25 -0700
Reply-To: Alistair Bell <albell@UVIC.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@UVIC.CA>
Subject: Re: Dometic in 100F ambient?
In-Reply-To: <c4e7c5f90708161347y283e170doaa34f6db22dd804f@mail.gmail.com>
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Ah the dometic threads, such a sign of summer :)
Its not coincidental that I have been thinking about the Dometic a
lot recently, what with brainstorming with fellow list member P.
Chubbuck and adding some stuff to the vanagonwiki. I have, and many
other's too, posted temp data and modifications to the stock fridge
( i understand that record of the list's emails are collected and
organised in some sort of "Archive"), and in the last 2 days I have
tried couple more things.
1. I replaced my little muffin fan on "icebox" grill with a littler
and quieter one (intel branded CPU cooler). the interior fan is good
mod. I recorded some fridge temps after the mod, remember this is
Victoria BC , not Tuscaloosa, so ambient temps are more civilised. I
kept the van closed tight, new interior fan on, fridge empty.
time fridge temp van temp elapsed time notes
18:00 27.4 25.7 0
18:10 28.1 26.8 10
18:15 25.7 27.1 15
18:20 23.5 27.4 20 back fan on
18:30 19.7 27.4 30 back fan on
18:55 12.1 28.2 55 back fan on
19:05 9.9 28.1 65 back fan on
19:11 9.0 28.1 71 back fan on
19:32 6.6 27.8 92 back fan on
19:44 5.6 27.6 104 back fan on
19:57 4.8 27.4 117 back fan on
20:10 4.1 26.9 130 back fan on
20:23 3.6 26.5 143 back fan on
21:05 2.2 24.8 187 back fan on
not bad performance. the back fan is a muffin fan i used to replace
the stock fan. I have to admit it is not as efficient as the stock
fan, it stay on more, doesn't cycle as much.
My set up as of yesterday also had a muffin fan (switched) attached
to grill on left side of stove unit, right adjacent to the stowage
bins. You can feel the waste heat from the fridge come out there. I
(and I think others) thought a fan there would help cool the back
coils of the fridge. I think it does but, in the summer, that hot air
now blowing rather than convecting is not cool :)
this afternoon i had the chance to pull the fridge out of the van to
give it a once over. I had left the fridge running after my temp
recording expt and found next morning the flame had gone out. I
wondered if the by-pass jet in the thermostat control had plugged or
maybe it was a combustion chamber problem. Turned out I was out of gas.
But i pulled the fridge. The by pass jet was clean. The combustion
chamber was dirty. fine metallic dust, which looks like it was coming
from the inlet and exh. pipes. I blew the pipes out with compressed
air, blew the main jet, sealed the cracked grommets where the
thermoprobe and piezo connect. I also removed the side grill fan and
did the mod to the city water access port, adding a switched muffin
fan. So instead of a fan just pushing hot air faster into the cabin,
i have a fan pushing the hot air out of "flapped" city water port.
That port mod looks like a winner, hats off to the list-members that
invented it.
Alistair
'82 westy, diesel converted to gas in '94
http://www.members.shaw.ca/albell/
On 16-Aug-07, at 1:47 PM, neil N wrote:
Hi Todd.
just thought i'd throw in my .02 here.
Have been in mid 80's to 90 F weather in B.C. interior. Temps in van
slightly higher. Fridge has maintained (when driving, or at camp with
open
slider door) low 40's and down to 28 at night. (it's much cooloer
outside at
night) When I parked a the mall here, it was 86. Fridge is at 39.
I have found an average of 40F differential.
I have a 5" fan in place of stock fan at rear, and of real use an
internal
CPU fan. FWIW the thermal has the rear fan on almost all the time,
but of
course fan is switchable.
Also of note I did a lot of maintenance/trouble shooting recently, so
this
has helped with efficiency.
Neil.
On 8/14/07, Todd Last <rubatoguy@comcast.net> wrote:
>
> Isn't it a fact of the design of the Dometic (or any ammonia
> apsorption
> fridge) that you are not going to get any better than 20-30
> degrees lower
> than the ambient temperature?
>
>
> Todd
> '88 Westy
>
>
> -------------- Original message ----------------------
> From: Michael Diehr <md03@XOCHI.COM>
>> After this last weekend's positive experience with a coleman xtreme
>> cooler in 100F+ temperatures, I'm wondering if there's even any
>> reason trying to fix up the Dometic.
>>
>> First question -- has anyone ever had a working dometic provide
>> adequate cooling in 100F+ temperatures?
>>
>> Looking at the coleman cooler, I notice that it has almost 2" of foam
>> insulation. Looking at the dometic, it seems to have very little
>> insulation, and it also seems to be self-defeating as it dumps so
>> much waste heat under the cabinet, so it's basically bathing itself
>> in hear.
>>
>> Second question -- is re-insulating the dometic with some sort of
>> modern insulator a possibility?
>>
>> Third question -- does venting the waste heat out of the van make a
>> serious difference? The dometic has a fan already, but all it seems
>> to do is stir up the air behind the cabinet. Would a fan that vents
>> the air outside of the van actually be better?
>
--
Please send me your Vanagon/Westfalia links!
http://vanagonlinks.googlepages.com/home
Neil Nicholson. 1981 Air Cooled Westfalia.
http://web.mac.com/tubaneil
