Fan Kit to Cool Down box

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Sean.Day72

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Recently installed a Nema 4X stainless steel enclosure at a remote slide gate location for access control. The internal temperature is reaching in the box 130F and its causing the UPS to fail. It is an APC UPS rated 104F. We have proposed to install a solar shield over the box and upgrade the UPS to a SOLA HD ups rated for 120F. We are also proposing to install a 24V fan kit with a retrofit louver to keep air circulating in the box. There will be a drip hood over the louvers to protect from driving rain. This is down here in Florida, will putting the louvers/fan kit into the box cause any humidity issues? The box is currently completely sealed up, but I feel the humidity can still get in there regardless? I want to see if there are any other issues I should be worried about? Mentioned to get a box with an A/C but at this point that would be pain to replace and I feel overkill for the equipment inside. I've used Air Conditioned boxes for SCADA control panels and at traffic light controls, but this box is pretty dinky compared to that stuff. If there any other solutions to cool down an outdoor box I'm all ears.

Box is 30"x24"x12" with Hardened Ethernet Switch (160F), Fiber Patch Panel, Doors Controllers (160F), 24VDC Power Supply (150F), and UPS(104F)
 
Sean.Day72 said:
Recently installed a Nema 4X stainless steel enclosure at a remote slide gate location for access control. The internal temperature is reaching in the box 130F and its causing the UPS to fail. It is an APC UPS rated 104F. We have proposed to install a solar shield over the box and upgrade the UPS to a SOLA HD ups rated for 120F. We are also proposing to install a 24V fan kit with a retrofit louver to keep air circulating in the box. There will be a drip hood over the louvers to protect from driving rain. This is down here in Florida, will putting the louvers/fan kit into the box cause any humidity issues? The box is currently completely sealed up, but I feel the humidity can still get in there regardless? I want to see if there are any other issues I should be worried about? Mentioned to get a box with an A/C but at this point that would be pain to replace and I feel overkill for the equipment inside. I've used Air Conditioned boxes for SCADA control panels and at traffic light controls, but this box is pretty dinky compared to that stuff. If there any other solutions to cool down an outdoor box I'm all ears.

Box is 30"x24"x12" with Hardened Ethernet Switch (160F), Fiber Patch Panel, Doors Controllers (160F), 24VDC Power Supply (150F), and UPS(104F)
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Nott sure that an internal air circulation fan will fix your problem. You need to get the heat out of the box.
Some sort of heat exchanger is probably what you need.
Do you know what the total power dissipation you have inside the enclosure?
 
190226-1527 EST

Sean.Day72:

Install a large finned on two sides aluminum heat sink in a wall or large face of the cabinet, and an internal circulating fan inside the cabinet. Also use higher temperature rated components. Outside shield from direct sunlight. Provided a weather shielded vent to allow humidity to equalize. Possibly include a drain hole. Don't use linear regulated power supplies.

Do some temperature monitoring under worst case conditions as the system presently exists.

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Only NEMA 3R for the problems I see in the rooftop HVAC world here in Clark County, NV. But even then, we have fuses and breakers blow/trip with the intense ambient heat inside those disconnects (and sometimes panels on a west-facing wall)

Heat mitigation is the solution. Sometimes I wind up moving the disconnect to a shaded side of the machine. Most of the time, I glue silver-faced Styrofoam to it. Works quite well, but most people don't care how the disconnect on the roof looks, just so long as they never hear about it again.
 
Sounds like you need:
1) Sun shade
2) Insulation of your cabinet
3) AC to get the heat out


I leave the sun shade to you. Anything that provides several inches of air gap between it and the cabinet, and keeps the sun off should suffice.

I've insulated several outdoor cabinets with 1" thick XLPE foam, with peel-and-stick adhesive film. It worked perfectly, and gave me roughly an R4 insulation value.

For the AC, call IceQube:

https://www.iceqube.com/air-conditioners/qube-series-mm/

I've used almost a dozen of their cabinet AC units over the last few years, and they're solid pieces of kit.



SceneryDriver
 
I would start with with a sun shield, some wall insulation if you can get it in there, and some passive ventilation. I would not put a fan kit in. No matter what you do it's going to be the same humidity inside the box is out most of the time. Keeping the sun off and reducing the solar gain will make a big difference in the temperature inside the Box
 
I don't know what the louver kit provides, but to keep the interior temperature of the box at ambient you need to set up once-through air flow as well as the sun shield. Simply recirculating the air inside the box won't buy you much. As an example, put an intake on the lower left sidewall and the fan exhaust on the upper right sidewall. That should provide a good "sweep" across the interior components.

Ironically, your relative humidity now is likely a bit lower than the outside air, since for equal water content a parcel of air at higher temperatures has a lower relative humidity, and the outside air gets heated once it enters the enclosure. That said, I doubt it is a huge difference and if it really becomes an issue you'll need to go to a more complicated scheme such as the one proposed by SceneryDriver.
 
What we don't seem to have is a handle on the enclosure internal heat dissipation. In my experience this needs to be considered especially with such a small enclosure. Doesn't help that the material is stainless steel. It has lower thermal conductivity that steel, even painted steel.​
 
Besoeker3 said:
What we don't seem to have is a handle on the enclosure internal heat dissipation. In my experience this needs to be considered especially with such a small enclosure. Doesn't help that the material is stainless steel. It has lower thermal conductivity that steel, even painted steel.​
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That's why I suggested intake/outtake louvers catty-corner to each other with the fan in exhaust mode.
 
gadfly56 said:
That's why I suggested intake/outtake louvers catty-corner to each other with the fan in exhaust mode.
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That's fine unless the enclosure has to be TENV.
Most of our enclosures were fan(s) blowing in at the bottom, exhaust at the top of the door. All had filters.
 
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