Date: Thu, 11 Jun 2015 18:17:56 +0000
Reply-To: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject: Re: GoWesty fridge fan report
In-Reply-To: <20150610202629.LNIP7.71774.imail@eastrmwml303>
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Removing the insulation behind the fridge can help, but works best if one as much as possible parks so that the drivers side is in the shade. It also helps the fridge work less in the evening where the outside cools down, but the inside of the van stays warm longer. To remove the insulation may not be sensible for everyone, but may be helpful for some.
Technical description.The body panels on the shaded side will generally cool to ambient temperature after some time in the shade.The sunny side will be warmer than ambient, since they absorb energy from the wide spectrum sunlight and convert this to heat. The heat is dissipated by heating the nearby air. This requires a temperature difference, so after some time in the sum a body panel will be warmer than the ambient temperature. How much depends on the "lightness" (technical term albedo) of the paint. Greys and colors often have albedos of 0.3-0.5, meaning they reflect 30-50% of the light energy, and absorb 70-50%. "Whites" aren't equally white, but can range from 0.5 to over 0.9. Sunlight on a perfectly clear day provides about 1kW into a 1 square metre area directly facing the sun. A bright white can reflect about 90% of that energy and only absorb about 100w/m^2. A grey or colored surface would absorb 500-700W/m^, 5-7 times as much. Sunlight going through the windows will bounce around inside the van and eventually almost all be absorbed. Hence the windows are a main contributor to the heating a vehicle. (That's why those reflective sunshades for windows are really helpful).
A vehicle is generally hotter inside than the outside temperature on a sunny day (as experience tells us). The shaded side of of the body panels will be cooler than the vehicle interior, so removing the insulation and exposing the fridge to this lower temperature can help.
Martin
On Wednesday, June 10, 2015 6:26 PM, "mcneely4@cox.net" <mcneely4@cox.net> wrote:
Hmmm..... . Even with a silver tan body panel (I don't recall VW's name for this color, but it is pretty light), in the baking sun it gets hot enough for the fan to run when the refrigerator is off. Without insulation the inside of the body panel would get even hotter, I would think. It would seem like that would impair rather than help performance. Help me out here. mcneely
---- Poppie Jagersand <poppie.jagersand@YAHOO.CA> wrote:
>
>
>
> On Wednesday, June 10, 2015 5:47 AM, Jim Felder <jim.felder@GMAIL.COM> wrote: >But also as I installed the replacement fan I did everything one could
> >possibly do to the seals, the burner, and the flue. The flame roars so that
> >even I have no trouble hearing it with my ear anywhere near the flue vent
> >if I'm outside on the drivers side.
> How did you make the flame "roar"? Change the orfice in the burner?
> B.t.w. In my '82 Westy I removed the fibreglass insulation in the wall panel behind the fridge. This improved the fridge performance noticeably. (It didn't occur to me to to do before/after delta T measurements). I'm guessing the insulation removal behind the fridge might help in two ways: More room behind the fridge so more air to circulate. Additional cooling of the air behind from the now non-insulated metal wall. My '82 is white. This might not work on my gold color '85 or any dark colors. In the '85 I use a 50mBar regulator in place of the stock 30mBar, which increases the power to the fridge by 30% as I mentioned in a post 4 days ago. There is no change in sound; no roar at 50mBar.
> Martin
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David McNeely
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