Insulation / Material for Rack cooling needed

[dturner71.dt]

OK guys. I need some help. I have the following items :

• Tripp Lite SRCOOL12K SmartRack 12,000 BTU 120V Portable Air Conditioning Unit
• IBM Server rack 42 U
• Supermicro 4 u server

I need help with finding a foam or insulation solution for the front and rear rack doors. The AC unit resides in the bottom of the rack while the server is in the middle. The exhaust is currently vented through the top of the rack and I want to insulate the whole rack to have better cooling instead of cooling the garage itself. Any advise is helpful. Thanks.

Dustin

 

[Nick2253]

That's an interesting setup. Typically, rack-mounted equipment takes in air in the front, and vents to the back, so doing a bottom to top thing is definitely different.

The easiest way to insulate the rack, in my opinion, is to get some fiberglass batt insulation and attach it on the outside. If you put the insulation inside the rack, it might block the airflow; I'm not sure how much space you have between the door and the front of the rack. However, if you put insulation on the outside, you'll probably want to cover it with something to prevent people from touching it.

However, you might be over thinking it with the insulation. As long as you seal up the rack, I can't imagine that you're going to have too much heat transfer through the rack itself; you biggest heat transfer is going to be through the exhaust.

 

[Redcoat]

Aluminum foil faced insulation bats, foil out, would work. Or paint it gloss white (I assume it's now black) to reduce the panel emissivity and thus its potential rate of reception of heat by radiation. If you weren't cooling the interior directly you would want it black/dark to improve emission to the cooler ambient. Or just don't worry about it - I agree with @Nick2253 that the heat pickup through the panels will be minimal.

 

[dturner71.dt]

I'm just trying to block the ac from leaking out the front or back doors through the vents. Not sure I need real insulation to do that. I was looking for something this insulated or not, to cover the holes. The rear door will be 90% covered with the bottom open for ac intake.

 

[Nick2253]

to cover the holes

Cardboard and duct-tape unless you want to get fancy.

 

[dturner71.dt]

Cardboard and duct-tape unless you want to get fancy.

This is a last resort option if I can't find what I'm looking for.

 

[Nick2253]

This is a last resort option if I can't find what I'm looking for.

If you really want to get fancy, you're honestly going to spend a bunch of money that you don't need to spend. Cardboard not only has insulating properties (which goes to your first point), it's cheap and readily accessible in the required sizes.

If you gave me an unlimited budget to do this, I would get large sheets of plexiglass, cut to size to fit the doors. I would drill and tap the plexiglass, and drill holes through the front door to allow me to screw in the plexiglass. Then, I would use some expanding foam or calking to seal the edges around the plexiglass. To seal the rest of the rack, I'd probably use caulking, depending on the gap size. For all opening/removable panels, I'd get door/window weather seal strips to allow the panels to be easily removed while also providing a good seal.

 

[Redcoat]

There is foil-faced wide tape at Home Depot.

 

[tvsjr]

If you don't care about money, why not just buy solid doors for your rack? They probably make them. If they don't and you want pretty, I'd suggest your local sheet metal shop... have them cut some thin aluminum to fit inside the door, then powder-coat it. Attach with nuts and bolts.

You do need to add the exhaust ducting kit to that AC. I'd also be concerned that it will freeze up (that's not an inverter-based unit... it's on or off... and your single server won't generate enough BTUs to keep the whole cabinet from freezing).

 

[dturner71.dt]

The exhaust duck is already hooked up. The unit is set for 72 degrees and the fan is variable. On high when it needs to be and on low when it's not needed. Been running 2 of these in a server room for a couple years without issues.

 

[tvsjr]

Right... in a server room, where you're conditioning a large space. A fairly small server room would be 512ft^3 (8x8x8)... your cabinet is something like 2x4x8, or 64ft^3. And you probably have substantially more heat load in a server room than you do from 1 4U server in a rack. Some AC units can reduce the compressor speed (inverter-based mini-splits being the most common). That unit has two fan speeds, but the compressor is either running or not. In fact, the fan on low may cause things to freeze up faster, thanks to less air movement across the coils.

 

[Redcoat]

Well, asking for "insulation" threw us off. @Nick2253 gave you lots of good ideas - a couple of comments though - I wouldn't use cardboard for fear that critters would chew into it, nor Plexiglass because it's too expensive and you don't need anything you can see through(?) - if I wanted sheet goods I'd go for Masonite.

But I still like the foil tape if what you are doing is sealing over holes and vents/louvers by applying something on the inside of the panels.

@tvsjr is correct about the exhaust vent, and, of course, as you mention, you'll have an air intake at the bottom of the rear panel. If this is in your garage I would put a filter medium of some sort on that inlet to reduce the potential for the ingress of dust.

Your need for other sealing will be dictated by whether the final installation has a negative or positive internal pressure - if it's negative I would seal the panel and door joints as @Nick2253 indicated in order to keep the dust out.

 

[Linkman]

Faced ridgid foam insulating panels. Something like https://www.homedepot.com/p/R-Tech-2-in-x-4-ft-x-8-ft-R-7-7-Rigid-Foam-Insulation-310891/202532856 just pick the thickness that works for you. Tape it, or use panel glue if you're going for permanent.

 

[dturner71.dt]

Ok. So cardboard is out.

What are your thought on this then? :

https://www.homedepot.com/p/1-16-in-x-4-ft-x-8-ft-Plastic-Panel-63003/202090190

Thanks.

 

[Constantin]

I second considering using panels of foil-faced rigid insulation. Polyiso will get you R6.5 per inch, is light, easy to glue on (spray adhesive). Easy to cut with a knife, edges can be finished with Al tape or Black duct tape (Gorilla brand) for a more finished appearance.

12kBTU is a lot of cooling capacity. That system will likely short cycle a lot. Is it split?

 

[Nick2253]

I wouldn't use cardboard for fear that critters would chew into it,

If you're putting the cardboard inside the rack, I don't think this would be a problem. Or, rather, if you have holes large enough for critters to get through, then you have bigger problems. Critters aren't going to just stop at cardboard; they'll go after cables just as readily.

 

[dturner71.dt]

Why I'm thinking some sort of plastic at this point. We have termites here in Florida.

 

[Constantin]

Rigid foam insulation is usually treated for termites. Otherwise, you wouldn't be able to use it as a foundation insulation below slabs, etc.

Your biggest issue is potential flammability, hence my suggestion to go with PolyIso, as it's foil faced on both sides.

 

[Nick2253]

We have termites here in Florida.

Then yes, for that reason, I would steer you away from cardboard.

 

[Chris Moore]

Why I'm thinking some sort of plastic at this point. We have termites here in Florida.

I don't know how well your garage is protected from rodents, but I had some rats get into mine and they gnawed insulation from several extension cords before I got them out of there. Keep your eyes open for such infiltration.

I second the PolyIso insulated panels, but I looked on the Home Depot site and the thing that caught my eye was the diamond plate sheets. Too bad they are like $150 each.