I am looking at a weather proof enclosure for some electronic gear. It will be fairly small, smaller than a breadbox (slightly smaller than a shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so a display can be seen. The electronics inside will dissipate around 5 watts. But I'm more concerned with solar heating. I can't seem to find any info on what temperatures I might expect inside the box. I'm looking at using an e-paper display which is only rated for use up to 50 �C. I'm a bit concerned this will not be high enough for use in direct sunlight in the US. Even here in the mid-Atlantic area surface temps (for example a sidewalk) can be too hot to touch which is likely 50 �C. I can only imagine that a sealed enclosure would be above that temperature. I'd hate to require the unit be kept in the shade. A big advantage of using e-paper displays is their high visibility in direct sunlight. Anyone have experience with similar units? -- Rick
Insolation of Electronic Equipment
Started by ●June 28, 2015
Reply by ●June 28, 20152015-06-28
On Sun, 28 Jun 2015 00:49:22 -0400, rickman <gnuarm@gmail.com> Gave us:>Anyone have experience with similar units?No need to be insolent!
Reply by ●June 28, 20152015-06-28
On Sun, 28 Jun 2015 00:49:22 -0400, rickman wrote:> I am looking at a weather proof enclosure for some electronic gear. It > will be fairly small, smaller than a breadbox (slightly smaller than a > shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so > a display can be seen. The electronics inside will dissipate around 5 > watts. But I'm more concerned with solar heating. I can't seem to find > any info on what temperatures I might expect inside the box. > > I'm looking at using an e-paper display which is only rated for use up > to 50 °C. I'm a bit concerned this will not be high enough for use in > direct sunlight in the US. Even here in the mid-Atlantic area surface > temps (for example a sidewalk) can be too hot to touch which is likely > 50 °C. I can only imagine that a sealed enclosure would be above that > temperature. I'd hate to require the unit be kept in the shade. A big > advantage of using e-paper displays is their high visibility in direct > sunlight. > > Anyone have experience with similar units?No, but I've worked with mechanical engineers who have had to do this same thing. The term you want to search on is "solar loading". Try that. -- www.wescottdesign.com
Reply by ●June 28, 20152015-06-28
On Sun, 28 Jun 2015 00:49:22 -0400, rickman <gnuarm@gmail.com> wrote:>I am looking at a weather proof enclosure for some electronic gear. It >will be fairly small, smaller than a breadbox (slightly smaller than a >shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so >a display can be seen. The electronics inside will dissipate around 5 >watts. But I'm more concerned with solar heating. I can't seem to find >any info on what temperatures I might expect inside the box. > >I'm looking at using an e-paper display which is only rated for use up >to 50 �C. I'm a bit concerned this will not be high enough for use in >direct sunlight in the US. Even here in the mid-Atlantic area surface >temps (for example a sidewalk) can be too hot to touch which is likely >50 �C.I can touch a 50C metal surface for any amount of time. At 60C, my limit is about 1 second. I can interpolate pretty well between. I have a couple of books on electronic cooling, and none are especially good. None mention outdoor enclosures. You could easily experiment. http://www.hoffmanonline.com/stream_document.aspx?rRID=233309&pRID=162533 suggests 40F rise for a grey box in sunlight. Your display may fail cold, too. -- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●June 28, 20152015-06-28
On Sun, 28 Jun 2015 00:49:22 -0400, rickman <gnuarm@gmail.com> wrote:>I am looking at a weather proof enclosure for some electronic gear. It >will be fairly small, smaller than a breadbox (slightly smaller than a >shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so >a display can be seen. The electronics inside will dissipate around 5 >watts. But I'm more concerned with solar heating. I can't seem to find >any info on what temperatures I might expect inside the box. > >I'm looking at using an e-paper display which is only rated for use up >to 50 �C. I'm a bit concerned this will not be high enough for use in >direct sunlight in the US. Even here in the mid-Atlantic area surface >temps (for example a sidewalk) can be too hot to touch which is likely >50 �C. I can only imagine that a sealed enclosure would be above that >temperature. I'd hate to require the unit be kept in the shade. A big >advantage of using e-paper displays is their high visibility in direct >sunlight. > >Anyone have experience with similar units?Automotive in-cabin electronics is usually rated for an 85C ambient (some manufacturers use 70C but they must not sell in Arizona ;-). It would probably be a good idea to provide shade for your box. It might be enough to use a double enclosure with plenty of air movement between the two.
Reply by ●June 28, 20152015-06-28
On 6/28/2015 11:15 AM, John Larkin wrote:> On Sun, 28 Jun 2015 00:49:22 -0400, rickman <gnuarm@gmail.com> wrote: > >> I am looking at a weather proof enclosure for some electronic gear. It >> will be fairly small, smaller than a breadbox (slightly smaller than a >> shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so >> a display can be seen. The electronics inside will dissipate around 5 >> watts. But I'm more concerned with solar heating. I can't seem to find >> any info on what temperatures I might expect inside the box. >> >> I'm looking at using an e-paper display which is only rated for use up >> to 50 �C. I'm a bit concerned this will not be high enough for use in >> direct sunlight in the US. Even here in the mid-Atlantic area surface >> temps (for example a sidewalk) can be too hot to touch which is likely >> 50 �C. > > I can touch a 50C metal surface for any amount of time. At 60C, my > limit is about 1 second. I can interpolate pretty well between. > > I have a couple of books on electronic cooling, and none are > especially good. None mention outdoor enclosures. > > You could easily experiment.I'm trying to figure out if this is feasible given the limits of the display without much investment. Maybe the box company will front me a unit. I guess I'm just pathologically cheap.> http://www.hoffmanonline.com/stream_document.aspx?rRID=233309&pRID=162533 > > suggests 40F rise for a grey box in sunlight. > > Your display may fail cold, too.The cold end I have covered if the display company will come up with a controller. It is a bit odd, but they shelved their own controller (FPGA based) when a customer produced a controller chip that works much better. The display company has a line that works -25 to 50 �C. The controller chip is only rated 0 to 40 �C oddly. In a couple of discussions with the display company contact I was not able to get them to provide specs on the display sufficient to design my own controller (most likely in an FPGA). Display company is coming out with a new controller chip that will be integrated into the display, but no word on an extended temperature display. I believe if I were buying 5K a year they would be more forthcoming. I'm only interested in this product if I can use the ePaper type display which I believe would stand out in the market. Likely it would suit a niche application which is exactly what I would like to achieve. So without the ePaper display, I don't think I would try to make this a standard product. -- Rick
Reply by ●June 28, 20152015-06-28
On 6/28/2015 11:30 AM, krw wrote:> On Sun, 28 Jun 2015 00:49:22 -0400, rickman <gnuarm@gmail.com> wrote: > >> I am looking at a weather proof enclosure for some electronic gear. It >> will be fairly small, smaller than a breadbox (slightly smaller than a >> shoebox in fact, around 8" x 6" x 3") and have a clear plastic front so >> a display can be seen. The electronics inside will dissipate around 5 >> watts. But I'm more concerned with solar heating. I can't seem to find >> any info on what temperatures I might expect inside the box. >> >> I'm looking at using an e-paper display which is only rated for use up >> to 50 �C. I'm a bit concerned this will not be high enough for use in >> direct sunlight in the US. Even here in the mid-Atlantic area surface >> temps (for example a sidewalk) can be too hot to touch which is likely >> 50 �C. I can only imagine that a sealed enclosure would be above that >> temperature. I'd hate to require the unit be kept in the shade. A big >> advantage of using e-paper displays is their high visibility in direct >> sunlight. >> >> Anyone have experience with similar units? > > Automotive in-cabin electronics is usually rated for an 85C ambient > (some manufacturers use 70C but they must not sell in Arizona ;-). It > would probably be a good idea to provide shade for your box. It might > be enough to use a double enclosure with plenty of air movement > between the two.It is looking like that is the direction to head. Maybe not a double enclosure, but require shade for summer use. A thermometer would be included and it will have a network connection, so it can phone home to complain that it needs another spot. -- Rick
