Yeah, live load makes a big difference. Lots of live load in a small box, the color of the box does not matter much. Little live load in a large box, color makes all the difference.
From: castarritt . Sent: Friday, August 16, 2019 8:16 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Solar load All of our DDB boxes have the brushed metal finish. I painted one of them with some white elastomeric roof coating stuff from Lowes that is meant to reflect solar energy, and the peak internal temp only went down ~5°F. We have a lot of gear in that box, so I think an application with a larger ratio of solar gain to internal heat generation would benefit more. After the paint failed to solve the problem, I replaced the 110cfm fans with a pair of 48vdc 250+cfm fans, and the temp went down 20°F; it does make a lot more noise though. On Thu, Aug 15, 2019 at 6:31 PM Ken Hohhof <af...@kwisp.com> wrote: The difference between standard machine grey and just bright white spray paint from the hardware store is dramatic. I suspect everything beyond that is incremental. Also back around 2005 when I ordered my first outdoor cabinet from DDB, I thought I wanted unpainted metal aluminum since all the traffic control boxes I see are plain metal or stainless steel. The salesperson said I absolutely didn’t want plain metal because it would get hot in the sun and what I wanted was the cream color. From: AF <af-boun...@af.afmug.com> On Behalf Of Bill Prince Sent: Thursday, August 15, 2019 6:19 PM To: af@af.afmug.com Subject: Re: [AFMUG] Solar load If you look up insulating paint on Wikipedia, the entry there says all ceramic heat-reflective coatings are snake oil. I did find a good discussion on Scientific American (https://www.scientificamerican.com/article/benefits-of-insulating-paint/). They don't exactly describe it as snake oil, but they also suggest that you not get your hopes up. I suspect you can get your best results with a coat of reflective white paint, and try to keep it clean. bp<part15sbs{at}gmail{dot}com> On 8/15/2019 1:12 PM, ch...@wbmfg.com wrote: Be interesting to do a bake off between this and the plain “satellite white” I use. I have always found it interesting that highly reflective things like polished aluminum, chrome and silver paint seem to be really bad at reflecting heat/sun. But we have all grabbed a chrome wrench that has been left in the hot summer sun and realized hot much it absorbs. I am guessing what we see as reflective, Infra Red sees as flat black. From: Bill Prince Sent: Thursday, August 15, 2019 1:46 PM To: af@af.afmug.com Subject: Re: [AFMUG] Solar load Which reminds me of this material that a friend clued me in on. You can get this at Home Depot (for example). It is pricey; around $250 per 5 gallon bucket, AND it needs a top coat of another material at near the same price. However, for an advertised reduction in temperature of over 60 degrees F, it may be worth a look. https://superiorcoatingsolutions.com/super-therm/ bp<part15sbs{at}gmail{dot}com> On 8/15/2019 12:35 PM, Lewis Bergman wrote: I remember Chuck doing a study on this same subject so I thought there might be some interest. Cabinet heat load -- Lewis Bergman 325-439-0533 Cell ---------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -------------------------------------------------------------------------------- -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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