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Case & UPS & Fans

Case with Uninterruptable Power Supply and Low-Strain Cooling
  [vote for,

Those who read this may mention the average laptop computer and claim that this idea is baked. But I don't want this in a laptop.

NOTE: The "Case" part of the title of this Idea is described last.

Consider the power requirements for the average desktop computer. If you want your machine to keep working in spite of minor power losses, then the usual solution is to get an external Uninterruptable Power Supply device. Now, have you ever looked closely at what the poor electric power has to go through, to get at your computer?

From the wall outlet, you may likely have a Surge Supressor gadget, to deal with momentary "spikes" in the line voltage. Such spikes can damage electronic equipment, and so must be prevented. Many UPS gadgets include built-in spike protection, but some people (like me) prefer to take as few chances as possible, and invest in additional protection. See, many surge suppressors are designed to protect your system by failing. If such a suppressor is built into your UPS, how can you be sure it hasn't invisibly failed? So add a few external suppressors, to PROTECT the suppressor inside the UPS....

OK, next, inside the UPS, the power gets converted to a nice low voltage, suitable for charging a storage battery. Then the power gets boosted back up to the same "line voltage" as the wall outlet. If there is a momentary power loss, the battery can compensate for it.

Next, power flows to the Power Supply Unit inside the computer case. This device converts line voltage down to at least three different low voltages (12v, 5v, and 3.3V). The internal components of the computer either use that power directly, or include additional power transformation circuitry (RAM and CPUs these days can run on about 2V).

Do you see any semblance of inefficiency in the preceding? Let's make it simpler! Let's design the case to accommodate several consecutive surge-suppressor modules. The outermost one has the typical jack into which the connecting cord brings power from the wall. it has an indicator light to show if it has failed. When it does (almost inevitable), you can take your time buying a new module, because the computer is using more than one. But try not to waste a lot of time! After you have it, you move ALL the modules closer to the outside of the case, remove and throw the bad one away, and insert the new one closest to the next stage of the power supply.

The power supply transforms the normal line voltage down to all the normal voltages needed by the computer. Here I'll assume the four previously listed, 12V, 5V, 3.3V, and 2V, but I do recognize that even lower voltages are coming down the progress-pipe in the future.

Now we use that power for FOUR battery packs! --one for each of those voltages. These all need to be redundant and hot-swappable with easy access through the computer case.

Finally, power goes from the battery packs to all the other components in the computer. No extra power conversion (especially back to line voltage!) needed. And this will probably conserve a reasonable chunk of energy, since such conversions as take place in the initially-described ordinary situation are far from 100% efficient. Thus the fewer, the better.

-----Added because [Ling] has a similar idea already posted-----

One other aspect of overall case & power-supply stuff involves the cooling fans. I'm going to recommend that WALL-VOLTAGE fans be installed. The power for these fans would be drawn after the surge suppression, the same as does the main power-supply-unit. This includes the PSU cooling fan and any other case fans, but NOT the CPU, GPU, and "chipset" fans. There really is no reason to add overall cooling to the power supply's load (helping them to die sooner, and also at least some voltage-conversion power-inefficiency can be avoided outright).

Now, what if the power fails? Well, remember that the main purpose of a UPS is to allow a graceful shutdown, not to let you run your computer for hours in the dark. This means that usually only a minute or two will go by, with the case fans not running, before you have turned the computer off. Since I particularly specified that the various fan-cooled chips NOT have wall-voltage fans, they will still be getting power from the UPS, and so they will not fry. I dare say that the short time heat builds up in the case, with no case fans running during the shutdown process, will not be especially harmful.


And now, what about the Case? They exist in many variations, from bland to extreme, so what new thing might I mention here? Well, it has occurred to me that few computer cases include wheels, which would make them more portable (like some luggage). And this particular computer could be somewhat heavy, due to the battery pack. Suppose we PLAN on a literally-massive transportable computer, and thus start with a gadget known as a "hand truck"...(see link).

Ok, the first thing we want to mount on this framework is a cord-reel to accommodate, say, a 50-meter power cord. Haul this baby to a LAN party, and it won't matter where they park you; it can reach an outlet somewhere! --Oh, that reminds me; reels for telephone and networking wires may also be desirable (but not essential, in these days of wireless communications), especially if you want speed and security.

Next, How about a small gas-powered generator? This should obviously be located at the base of the framework, due to its mass. It could supplement the battery pack, perhaps to be automatically cranked up after, say, a two-minute power outage. If possible, we would want a multi-voltage generator, mostly low voltages perfectly matched to the needs of the system, but also including wall voltage to keep the case fans running. The engine for this generator should be fueled by natural gas or propane, because they burn cleaner than gasoline, for indoor use (adequate ventilation is still required, though!).

Next, above the generator, is the main power conditioning unit. This box would include the surge suppression devices and voltage transformation circuits, along with the battery pack.

Next, above and attached to the power box, is the main computer case, holding all the usual stuff like circuit boards and disk drives.

Now, on the OTHER side of the hand-truck framework, we mount a fold-out chair, a fold-out keyboard and mousepad holder, and a flat-panel monitor. Also choose your option: speakers or headphones. This means you can crash any LAN party because you are bringing a complete portable workstation!

Vernon, May 04 2004

Tougher than the average surge suppressor http://www.brickwall.com/
The makers brag about how this suppressor will never fail. These units are quite expensive, though, so perhaps you really are getting what you pay for. [Vernon, Oct 04 2004, last modified Oct 21 2004]

PSU/UPS Combo http://www.halfbake...a/PSU_2fUPS_20combo
Basic idea is the same. [Ling, Oct 04 2004]

Installing 120Volt Fans http://slashdot.org...47248.shtml?tid=126
Scroll down to the bottom of the page, and look for "Personal Preference". This post is USA-centric, and is about two years old. Europeans will want higher-voltage fans, of course. [Vernon, Oct 04 2004, last modified Mar 01 2014]

Hand Truck http://www.amazon.c...nt&m=A3RYRK9VLWOZEH
A framework like this one is fairly versatile. [Vernon, Oct 04 2004]

Forum for Electronic Design Automation http://edaboard.com
Get more appropriate feedback for your truck mounted computer. [neelandan, Oct 04 2004]

Tesla Turbine http://en.wikipedia.../wiki/Tesla_turbine
Operates using the Coanda Effect, which Nikola Tesla apparently independently discovered about the same time as, or even before Henri Coanda. [Vernon, Oct 04 2004, last modified Oct 21 2004]



       A computer case could be built to hold a battery and the associated power conversion paraphernalia that make up an uninterrupted power supply. It would make the case far heavier, it will have to be made of a stronger material and so is going to cost more.   

       We do not want more batteries. One is quite enough, and it makes us troubles enough in its need for service. And Lead Acid Accumulators are going to emit acid fumes which are going to ruin the processor cooling fan's bearings, for sure.   

       The custom made voltages required by modern motherboards are well looked after by a custom power supply module. Its input is standardised to the line voltage, and the UPS's output is at line voltage, so that in a pinch you can cut out the UPS and plug the machine directly into the mains.   

       The idea you mention remains an interesting design problem, and I look forward to your particular solution, dear Vernon.
neelandan, May 05 2004

       [neelandan], why do you assume that lead-acid batteries will be used in any implementation of this Idea? Sure, they cost less than, for example, lithium-ion, but if we need to avoid fumes, and if we want lesser weight, then non-lead-acid is the way to go. Also, it is interesting to recall that lithium-ion have a rather greater power density than lead-acid, so if all we want is the relatively standard 10 minutes of uninterrupted power (enough to find out that you have a major power failure, and then to shut the computer down gracefully), then we don't need even as big a battery as laptops use!   

       On the other hand, lithium-ion cells do 3V, and it might be most efficient to instead use a cell-type that only outputs 1 volt. (The electrochemistry of battery cells can offer a number of possibilities.) The result of having a lower voltage is that we can imagine a row of a dozen such cells, and we can draw power from different combinations of them (a pair to get 2V, three for 3V, and so on). In this way we only have one "battery pack", but all the needed voltages for the computer!   

       [ling], I do agree that the main idea is very similar. I also note the date of your posting, and can only say that the reason I didn't post mine sooner (like when I first joined this place, years ago) is because I've actually tried to have one built. The engineer I hired to do it has not been able to succeed at it (too much heat, not to mention a couple of genuine mistakes that essentially blew out all the electronics in the PSU). I was hoping that the idea could lead to some income, so why give it away? But now I've basically given up on it, and am leaving it half-baked. However, to differentiate this idea further from yours, I will add another topical notion and a link, the date of which should indicate that I have indeed been thinking about case-and-power-supply stuff for some time. (I could go on to include a whole new circuitry proposal for efficiently converting ordinary AC to low-voltage DC, but I still have hopes that it may yet pay off. So this here Idea should persist until I give up on that one, and then decide to add it!)
Vernon, May 05 2004

       Folks, because of the Title of this Idea, I felt I had to add some stuff about a Case.
Vernon, May 06 2004

       Interesting. While the world is veering towards ever smaller computing devices, you propose to build a behemoth smelly smoke belching monster.   

       I suggest you take this thread to another, more appropriate, forum. See link.
neelandan, May 07 2004

       Perhaps [Vernon] doesn't want his new idea stolen.
Ling, May 07 2004

       [neelandan], there are many quite large retailers in the Uhe USA that have propane-powered floor-waxing equipment (needed due to sheer size of floor area of store), and while they are noisy, they are not particularly smelly or smokey. And less noisy engines are possible (see link), especially when only a few kilowatts are needed. AND, of course, the engine will only need to run during a power failure!   

       Anyway, no matter how small your computer is, YOU still need some workspace to use it, whereever you happen to be. If that workspace is part of the design of this quite-portable wheeled computer "case", then what is your objection?
Vernon, May 07 2004

       OK. So... we have a wall socket. Lest a power surge should come down it, we are replacing the whole computer with a massive beast, occupying a large trolley, containing at least four batteries, several surge protectors and a natural gas generator? In the name of increased efficiency?   

       If you're worried about power surges and outages, then a UPS with replaceable surge protection modules is a good idea. It needn't be too heavy either. A nicad battery stores about 40 watt-hours per kilogram. Supposing your PC draws 500w. A 1kg battery will last about 5 minutes - more than the 2 minutes you need to shut down. Including the surge protection units, you'd only be adding a couple of kilograms to the case.   

       Cutting out the UPS stage that transforms power back up to 240v also makes sense. Feed the computer at 12v; that is (I believe) the voltage used for the majority of systems on a computer. Transform some power down to other voltages as necessary. Run the fans on 12v, that way they don't have to switch off in a power cut.   

       If I was worried about the reliability of supply, I'd buy a case with built-in UPS like this.   

       Making the case like a piece of luggage, with wheels and a pull-out handle - fantastic idea. Chuffed to bits, straight down to the store, proud owner of a decent transportable desktop.   

       But then going for a generator, distribution box setup, four batteries, a gas tank and hand truck? Just in case the power goes out?   

       If the power supply is dodgy where you live, by all means fit a backup generator in your house. If you're going to a LAN party and are still afraid of power surges/cutouts, take a laptop. Unless you live at LAN parties prone to regular power cuts, you're not gonna need a transportable generator. And if there is a cut at a party, then either everyone's using laptops, or all the other players' computers die and you're the only guy still playing...
david_scothern, May 11 2004

       Buy a nice barebones case, maybe even a small one like a micro-atx case.   

       Buy a Dell Precision M60 or AW Area51 or equivalent. Buy the port replicator option for the M60/A51. Buy a second battery for the M60/A51. Buy a 1394 internal optical drive of your choice (I like the Plextor DVD+/-R/CDRW drives, myself).   

       Modify the case, mounting the port replicator to the back of the case and simple mounting inside the case for the M60/A51. Add the optical drive to the usual drive bay.   

       Place the M60/A51 inside the case and attach external keyboard, mouse and monitor via the port replicator. Attach the M60/A51 KVM to the port replicator. Attach the optical to the 1394 port on the M60/A51.   

       Viola! Low strain cooled, high-perf, 4 hour UPS protected, desktop or tower form factor machine.   

       For travel you can just open the case and take the M60/A51 with you.
bristolz, May 11 2004


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