Cooling Equipment in a Cabinet
Cooling Equipment in a Cabinet
(OP)
I need to do a thermal analysis to make sure that the electronic equipment items in a 6 foot tall metal cabinet are not getting too hot when they are all running. The cabinet has solid walls on two sides, a door on the rear and a top. There is no front door. The equipment is placed into the cabinet from the front. So I am going to assume the input air is all room temperature. Currently I do not know if there is any type of fan being used to cool the equipment. Please tell me what equation I should use. Do I apply the equation to each equipment item in the cabinet or to the cabinet as a whole? I am not savvy when it comes to conversions, so I would like the explanation to be as simple as possible. I don't necessarily need to fully understand all the math, I just have to get the project done quickly to keep on schedule. I do not currently have data on any of the equipment item, but will be getting it soon. I am just trying to get a head start on the project, so I can just plug in values once I get the data sheets. I do not think I need to consider radiation given off by the metal cabinet itself, unless that is something very easy to do. I do think that they are expecting me to be looking at the convection within the cabinet and to determine if the air inside the cabinet will be hotter than the acceptable operating temperature of the most critical piece of equipment. They will also probably want me to size a fan if one is required. Thank you for your help.





RE: Cooling Equipment in a Cabinet
This is a crude estimate. Good luck.
RE: Cooling Equipment in a Cabinet
What units will the volume of air be in?
RE: Cooling Equipment in a Cabinet
Here's one:
thread248-158079: Rough Estimate for temperature rise in an electronics box
Keith Cress
kcress - http://www.flaminsystems.com
RE: Cooling Equipment in a Cabinet
I have been working on a similar problem. You need Cooling Techniques for Electronics Equipment, by Dave Steinberg. A fan, ventilating or circulating, makes a huge difference. You need to know.
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JHG
RE: Cooling Equipment in a Cabinet
As 3DDave said, all of the power your system uses will be put off into the air as heat so, using the heat capacity of air, your air supply temp, total system power, and your max acceptable air temperature rise dictated by the components you can figure out how many CFM of air you need to move in and out of the room and size your HVAC accordingly.
RE: Cooling Equipment in a Cabinet
John H
Pacific Coast HVAC
RE: Cooling Equipment in a Cabinet
I just re-read your comments.
The heat capacity of your air is not relevant at steady state.
On my problem, I was told the electric power going into the cabinet. As noted by 3DDave, all of this must be dissipated outside, somehow. With the reference I noted above, I have the means to work out ΔT at the outside face of the enclosure. I can work out ΔT through the wall of the enclosure. I can work out ΔT from the inside air to the wall of the enclosure. I can work out ΔT from the components to the inside air. For a given ambient temperature, I can estimate the temperature the components are running at. If this is too much, you need to reduce the ΔTs. Fans and heat sinks are an obvious solution. Heat sinking components directly to the outside wall is a solution. Heat pipes and thermo-electric coolers are fancier and more expensive, but they may be necessary.
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JHG
RE: Cooling Equipment in a Cabinet
The cabinet is supposedly missing one side, the front, so it isn't a closed box.
RE: Cooling Equipment in a Cabinet
I am trying to interpret what he is saying.
There is no front door, or there is no front enclosure?
If this was my design and it was open, I would worry about each individual module. The cabinet would be nothing more than a mount.
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JHG
RE: Cooling Equipment in a Cabinet
my favorite "I don't necessarily need to fully understand ..." As long as he doesn't neither do I.
RE: Cooling Equipment in a Cabinet
RE: Cooling Equipment in a Cabinet
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Cooling Equipment in a Cabinet
Is your cabinet enclosed, or open on one side?
If you dump heat to air, the air is cooler than your components. I suggest an infra-red thermometer. You can get one at Home Depot. You can measure the outside temperature of your components. Mine has a reliable class 2 laser, which makes an excellent cat toy.
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JHG
RE: Cooling Equipment in a Cabinet
RE: Cooling Equipment in a Cabinet