Freezer backup power that won't make a stink?
January 30, 2015 12:58 PM   Subscribe

My employers are looking into obtaining some sort of emergency backup power for a couple of specific, large appliances. Assuming gas generators are not an option, what would a person use to provide a couple hours of power for, say, a freezer capable of pulling 15 amps when the compressor turns on?

Some relevant background:

1) We're not looking to implement a full-scale power backup system for the entire lab. We can live for a while without lights and laptops. We're more thinking in terms of things like ultra-low-temp freezers, where in the event of an outage we'd benefit greatly from something that can (a) carry us through a short interruption and (if necessary) buy us enough time to move critical items elsewhere temporarily.

2) During the last major storm (well, major for this part of California) we did a "dry run" that involved renting a gas generator and setting it up outside the building. Power-wise it seemed adequate, but the noise and smell were pretty horrible and there was no way to move the generator to where it wouldn't pipe fumes into the office while still being close enough to reach inside via extension cords.

3) We're renters in a multi-office/lab suite. Single story. We have neighbors. This means that ideally our backup system could be stored and used inside our suite (not placed outside our lobby!) and would not entail any large, landlord-frightening infrastructure changes.

...so, to reiterate my basic question: what (if any) non-gas options exist for us to back up one of our big ultralow freezers for perhaps 2-4 hours at a stretch?

Something like a UPS would be perfect in terms of storability and quietness, but I'm having trouble finding UPSs that could handle the peak current draw requirements of the freezers we're looking at here. References, anecdotes, websites, vendors, and recommendations from personal experience are all welcome. Thanks!
posted by aecorwin to Technology (11 answers total) 1 user marked this as a favorite
 
How about a tank of liquid nitrogen?
posted by bdc34 at 1:11 PM on January 30, 2015


Everyone I know in Pharma (which is not a huge sample, but > 1) uses propane or LP gas generators for their lab freezers - I am assuming when you say you don't want "gas" you mean "gasoline". I think they still have to vent outside, but it's possible that can be done with existing plumbing.

Your freezer vendor would probably be glad to refer you.

If you have neighbors who are also labs, it might be worth talking to the landlord about a large building generator. It'll be attractive to future lab/medical tenants.
posted by Lyn Never at 1:11 PM on January 30, 2015 [1 favorite]


You can get UPSes big enough to run them - our datacenter is on one, and we've got several dozens of servers and drive trays in there.

You won't find them retail, however - all of the full size battery solutions I've ever used were bespoke - and were fairly expensive. Basically, you're looking for something like this. Your best bet is to find a contractor in your area who can install them - electricians that do lots of datacenter work are probably your best bet. You should make sure to budget for maintenance costs - batteries only last so long and need to be replaced periodically.

You can get stand alone units that aren't wired directly to the premises. I don't know too much about those - all of the ones I have specced out have been built in fixtures. The size and the cost will depend on how much run time you would like to have. At a certain point, generators are a much more economical solution.
posted by Pogo_Fuzzybutt at 1:12 PM on January 30, 2015 [1 favorite]


Instruments and freezers in the lab I work in (as a programmer, not as someone who really knows that much about the science machines) are backed up by a hardwired generator backup built into the building. There are also -70°C and -80°C freezers in the lab that, if power is interrupted, get flooded with liquid nitrogen.
posted by silby at 1:12 PM on January 30, 2015


You can get a UPS to do this but it won't be "off the shelf" and it may require some, relatively minor, infrastructure changes. A good design-build electrical contractor should be able to let you know what's involved and likely cost.
posted by meinvt at 1:12 PM on January 30, 2015 [1 favorite]


There are definitely UPS's that can handle the power draw, and could go for a while, but they'll be out of your price range. A UPS which could do an hour 15A will be in the $2k ballpark. Eaton, APC; any of the UPS makers make them big. We've got some 240V 100A systems, but that may have cost more than your office's rent for the year. And really, the only reason one has a UPS that big is 1) to handle the short power blips, and 2) make sure that one has time to get the generator running if there are issues and the power outtage is extended. You don't buy a 100K UPS so you can run a freezer for a weekend.

Really, a generator is the way to go. Look to getting a hookup on the roof; this would likely be cheaper than properly venting an indoor generator. Note, generators need periodic maintenance. Also note, if there's an actual emergency, many people might have already rented any generators available for rent. If you go through the annoyance to get a power feed to the roof (and have the roof certified to hold the weight of the generator and fuel, and have the fuel certified to be safely stored), just buy a generator and a service contract.
posted by nobeagle at 1:17 PM on January 30, 2015 [1 favorite]


Also note that there's a huge difference between cheap generators and something like the Honda eu2000i. Still be some gas smell, but you can stand next to the Hondas and talk, they're efficient, and part of why that is is that they're not blowing tons of gas out the exhaust without burning it.

But I'm with the posters up-thread: For your needs, you want a fixed LP generator on the roof.
posted by straw at 1:18 PM on January 30, 2015


Best answer: Looking fairly quickly: at Eaton your freezer, when running will be 1800VA. If you get the basic model, plus 3 extended battery modules, that would get you about 3 hours of solid runtime. If the freezer isn't running constantly, 1-2 exteneded battery modules might be enough for 2-4 hours of clock time. Ballpark $2500 - 6500. It's not something you can buy at future shop, but you're not going to suddenly by the sales person's best friend either. Plus it is mobile, and won't require talking with your landlord.

There's lots of models, and lots of UPS suppliers. Generators are cheaper.
posted by nobeagle at 1:31 PM on January 30, 2015 [1 favorite]


I used to work for a generator shop (sales, rentals, service, parts). We didn't sell UPS units, but we had a few places we could refer people who needed them. Standby generators are quieter and more reliable than portable generators, and are much less of a nuisance to the neighbors. When customers would come in looking for mufflers for certain portable generators, we would suggest to them that they buy longer extension cords. Sound insulated standby generators, though, aren't terribly expensive and make less noise than a car at idle. I'm not sure what sort of portable generator you rented but the shop I worked for would have rented you cable of adequate rating and length for a nominal fee. Was your rental an open frame thing with a lawnmower engine that came on the back of a pickup truck, or was a big enclosed rectangular thing on a trailer, possibly with the word "Whisperwatt" on the side? They are very different and I could see you being as happy with the latter as you were disappointed with the former, if that's indeed the sort of thing you rented.

If your stuff can stand a brief loss of power you can get away with a generator and manual transfer switch, where somebody has to walk over, start the generator and let it stabilize, and then flip the transfer switch. An automatic transfer switch is a better choice (if it is properly maintained) since it will start the generator for you and will reduce the amount of time you don't have power. Only in an absolutely critical situation would we have sold someone a system with an integrated UPS, since batteries are expensive and have venting requirements of their own. Integrated systems are pretty much only used in data center environments and hospital ICUs, since the cost of completely uninterrupted power is much higher than just the cost of a generator and transfer switch.

Also standby systems can be liquid propane, natural gas, or diesel fueled. We basically only sold LP systems to people who already had LP delivery worked out, sold natural gas systems to individuals who wanted generators for their homes and who already had NG lines (this was Oklahoma, so LP largely meant "farm" and NG meant "city"), and sold diesel to pretty much everybody else. Diesel is the best choice for standby power if the fuel's just going to be sitting there (like, on a roof or in a parking garage), and in an extended outage you can easily get more delivered.

So I'd recommend you talk to a generator shop about a quiet standby system and find out how disruptive the installation would have to be, then run it past the landlord. Could be that if you offer to pay for the installation the landlord will recognize it as an infrastructure improvement he can use to raise the base rent for the next tenants.
posted by fedward at 3:11 PM on January 30, 2015 [1 favorite]


Your cheapest solution by far is a decent quiet gasoline generator and a very long heavy duty extension cord. You can easily go 100 or 150 feet with an adequate gauge wire so that you wouldn't even hear it.
posted by JackFlash at 1:12 AM on January 31, 2015


Another vote for an LP or natural gas standby generator.
posted by werkzeuger at 1:15 PM on February 2, 2015


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