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By fkatzenb
#159184
Odd question for you.

I am thinking about buying a safe. When I was viewing one of the models, it had an outlet for 110vac, Ethernet, and USB. When I saw this, I knew this was the route I wanted to go. For a while, I have been concerned about my valuables, not just physical, but also the digital ones. Especially in the event of fire.

I understand the fact that features in a safe like that could make it more vulnerable, but that is something I am willing to trade off. My plan is to place my small backup computer into the safe and use the USB outlet for my wireless connection where I will keep a few computers sync'ed up to it. Unfortunately this will create heat and because of the typical padding in a safe, I am not sure this is easily expelled thru the body. I am not even sure the body is going to be that good for what I am about to proposed, but whatever.

I am considering one or two thermoelectric coolers that Sparkfun sells to try and expel the heat out of the safe. The first proposal is to setup liquid cooling on the backup computer's CPU and the two HDD and using the thermoelectric device to expel the heat from the liquid into the body of the safe. I am sure I would have to remove some of the padding in the safe and to burnishing the surface of the steel in the safe with some good thermo two part. The second thought was just cool the air in the safe with the thermoelectric device (probably two of them at the top).

Part of the problem is the fact that I cannot get Ethernet to the safe in an easy fashion. I considered Wake On Lan with my DD-WRT router to make it all work. Typically wireless USB dongles don't work with Wake On Lan. I even considered a timed event where the computer boots up at certain intervals and returns to sleep, however Windows tends to be unpredictable on when it wants to sleep... unless it is my work laptop and it likes to sleep at the most inconvenient times.

I am open to any and all suggestions.

Thanks!
Frank
By skimask
#159186
A) How much wattage does this "small" PC dissipate?
B) How big of a thermoelectric setup are you planning on buying'?
C) What is the overall efficiency of this setup you are planning on buying?
D) What is the thermal resistance of the safe?
E) Will you have fire extinguishers on hand for when the PC lights itself up?
F) Wouldn't it be a helluva lot cheaper, easier, safer, quicker, to encrypt the hard drive(s)? PC's are cheap. Data isn't...
If you're that worried about it, keep the PC on the outside, put the HD inside on a USB.
By fkatzenb
#159187
Point taken. I thought about doing the USB setup, but wasn't sure about the best way to prevent unauthorized access. Then your post reminded me of encryption.
By skimask
#159198
Ya, the only problem I see with your original method of doing things is...everything.
Peltier chip efficiency, heat transfer of the metal of the safe itself, getting good transfer from the chip to the case of the safe itself, and so on and so on.
The only place I see all of that leading to is a place I like to call "fried computer land" :)
By MichaelN
#159222
While other posters have a good point about it not being the best option, it certainly is feasible. There are plenty of small PCs that consume much less than 50W.

Peltier coolers are not very efficient - at best, they only shift about as much heat as the power they consume. That is, if you have a 50W device, it will move about 50W of heat and consume about 50W of electrical power, giving a total of 100W that needs to be dissipated on the “hot” side.

The Peltier device, with suitably large heatsink and fan, should go on the OUTSIDE of the safe, with an aluminum block to transfer the heat from the inside of the safe. The biggest issue I have is that you will compromise the fire protection of the safe by doing this, as the effective thermal path you’ve created for cooling will also allow heat from a fire to enter.

EDIT: the other big issue is that you'd need to cut a hole in the safe to accomodate the "heat tranfer" aluminum block. On a decent safe this will be very difficult.

One other issue is condensation that will occur on the “cold” side if you’re not careful. I’d suggest keeping the “cool” side to a modest temperature (say 25 degrees C) to avoid excessive condensation. You’ll need a temperature sensor and control circuit to achieve this.
By fkatzenb
#159260
Well I am going to with the HDD external enclosure in the safe with the computer outside of the safe. I plan to use encryption. All computers that sync data to it will be password protected to prevent unauthorized access. The safe does support USB 3.0. I think I will probably buy a external raid enclosure that I saw on Newegg. I will probably use an arduino to collect temps and ensure that windows can shutdown the enclosure appropriately. If not I will run a cat6 cable to it and setup wake on lan.