Keeping Computers (And People) Warm In Winter?

Grimwiz writes "Similar to a few of you, I have some of my computers on a UPS. However, the UK press have recently been warning that power supply interruptions are likely this winter and I've been pondering about upgrading my power protection from those few machines to include a few key house components. In particular, I need to ensure that the gas-powered (but electrically controlled) central heating stays working. I have reviewed a few solutions, including Solar / Photovoltaic or purchasing a generator but they seem to be hugely more expensive than my simple UPS solution, although they do provide a much longer lasting solution than running off batteries. (A battery solution becomes quite expensive if I require more than an hours backup.) My power requirements for a quiescent house is about 4amps @ 250V, and I'd like to survive at least 8 hours. What solutions do you recommend?"

Comments

I suggest

[Anonymous Coward]

A warm jacket.

Re:I suggest

[pyat]

or more generally, invest in good insulation for your house. It'll pay for itself in saved heating even if you never have a power-outage, and if you do lose power for a while, your house will stay warmer longer.

UPS + Generator

[Anonymous Coward]

Use a normal UPS to bridge the first few minutes in which you can comfortable start a generator.

Buy bigger batteries

[Repugnant_Shit]

I have a small, 20 minute UPS. Once the battery could no longer hold a charge, I took it out and replaced it with a higher capacity VRLA battery that I got from work. With one LCD and one computer, I get about 9 hours of reserve time. The UPS does not get hot, even when the battery has been significantly discharged. I plan on doing this to two other UPS that I bought at a flea market for $10.

its AC!

[Dr.Knackerator]

so sticking batteries in series to 250v is not going to be a good move.

stick em in parrallel and hook up a 240V inverter.

32ah is a bit on the weedy side, around 110ah is standard and easy to find. over in the uk they tend to be called leisure batteries. dont use normal car batteries they are not designed to be run down - you will damage them

I suggest...

[naturaverl]

Well, 4A @ 250v = 1000 W, for 8 hrs is 8 kWh. That's a lot, and would probably be very expensive to maintain with a battery-based solution. I'd say a generator would be the way to go.

Re:I suggest...

[Anonymous Coward]

The other thing you need to consider when designing your system: what power factor will you be dealing with?

You see, most UPS systems are rated in "volt amps". If you have a purely resistive load, that's the power drawn. However, as soon as you throw any inductors or capacitors into the circuit, the equation no longer holds. This is where the power factor comes into the equation.

You're talking about 4 amps at 250 V, over a period of 8 hours. That's 1000 watts for eight hours, or 8 kilowatt hours. However, this doesn't cater for the power factor -- if your house has a power factor of 0.8, for example, batteries capable of providing that current for that period of time will run your house for about six and a half hours. So you'll need to bring up the batteries to 10 kilowatt hours to compensate -- either that, or (if it's an inductive load) buy a whopping great big bank of capacitors to bring the power factor back up to a reasonable level.

Industrial sites have to deal with this; the power company doesn't like sites that draw excessive current compared with their power usage, and will bill them big time if their power factor is too low. Most residential sites aren't a concern in this regard; their usage is too low for the power company to worry.

If you've specced it out based upon the current draw (ie: sticking a current meter in series with the circuit), you've automatically compensated for the power factor. If you've done the maths based upon the power rating of the devices, though, you need to consider this stuff. Any competent electrician should be able to help you out here.

Gas - Electricity

[Gulthek]

If you have gas then you can get a natural gas electrical generator. Connected to the gas line, when power goes out some models will automatically ignite and provide power to the house, some require a manual ignition.

Cut the Fat

[Nehi the Ganchark]

Another approach you could take is to take steps to make your household more energy efficient -- upgrade your insulation, get energy star rated appliances, change to flourescents -- all of those things we should have learned in school and keep learning about in the adverts that come with our energy bills.

You could look into alternative energy sources, but since cost is a factor, I won't go into details, except to say the up-front costs can be prohibitive.

In all honesty, a generator IS your best option if you want to keep running in a blackout. You may be able to poke around and find a used one for 1/3 the cost of the new article.

If that's still not an option, build a fire pit and stock up on wood...

Don't really need heat for 8 hours.

[scattol]

It's quite likely that you don't need heat if your power interruption is only going to be 8 hours. During the Quebec ice storm we were out of electricity for 7 days. The house will stay decently warm for the first 2 days. It will be chilly for the next 2 and getting cold after that. But even after 7 days the appartement was still above freezing in weather that was always a little below freezing.

My recommendation: don't sweat 8 hours of power failiures.

That said, if you really need electricity, say to prevent perishable from going bad your best bet is a generator essentially because it's easy to refuel and keep going for days. You also get decent power in relatively small packages.

Re:Deep cycle marine battery

[theparanoidcynic]

Who modded this informative? 250 volts DC is not the same thing as UK line power. (250 Volts-rms @ 50Hz.) This idea is as dangerous as it is useless.

What you need is an inverter. The cheap ones that you can get anywhere would work fine for your computers, but for your furnace you'd need an inverter of the caliber used in off-grid homes. (Probably more than you want to spend.)

Re:How cold does it get in the UK during winter?

[Lumpy]

your tips are right except for the joke about the liquor. getting drunk will increase your chances of death in extreme temperature.

It does suprise me the number of people in civilized lands that are completely clueless to human survival.

If the house get's to 1 deg C your pipes are still very safe 0.5degC is where I would start to worry. about the pipes. Being used to winters regularly getting to -5 to -10degC and recieving at least 36-48 inches of snow by mid winter I usually get a good laugh from those that live in warmer climates and their lack of knowlege about life.

I would add to your tips. dress in lots of layers. a couple of undershirts with a regular shirt, a sweater and then a baggy sweatshirt, 2 pairs of pants on and then a regular jacket coupled with gloves and decent boots (3 pairs of socks, 1 plastic bag over each foot (if you venture outside) then in medicore boots can survive quite a long time in -3deg C weather out of the wind and elements. a Hat is a MUST if you venture out in any wind.

your computer can get down to -30 degC before possible dsamage, and then it's highly unlikely. This is negated by the silly people with water cooling and not using ethelyne glycol for freeze, heat protection.

layers are important, buy some long underwear or sweatpants just in case. In fact a pair of regular underwear, long underwear, and two pairs of jeans will easily protect a walking person in arctic temperatures if DRY for days.

finally, gloves. get some that are decent and good socks/boots. you can survive horrible temperatures while your nose., fingers and toes freeze solid and then fall off days later.

finally if it getr's really horrid, pitch a tent in your front room (a 4 season tent) and sleep in there. containing your heat in a smaller space will protect you massively in extreme temperatures.

but the best thing is to find a female that is unprepared and scared and convince her that she and her 2 friends must sleep naked together in that tent with you in order to survive...

you know use that shared body heat angle.. Chicks love the prepared rescue type... oh and don't shave for a day or so to look rugged... they dig that too...

Re:Need a generator?

[stratjakt]

Better yet, one of the hybrid gas/electrics, those things basically have what amounts to a mega-super-duper alternator, and you can plug right into the vehicles.

I just got back from Epcot, where GM had a display about their gas/electric hybrid pickups and how they were used during the Florida hurricane's as mobile power generation stations. Apparently you can plug right into one of them, and they'll give you 120 VAC @20 amps, which is not too shabby. (No doubt the UK model serves up 240VAC)

furnace won't work with UPS, don't bother trying

[sludg-o]

If your gas furnace's blower and exhaust fans run on electricity, which I'm pretty sure they do, you're not going to get more than a minute or two out of a UPS. Those big fans push a lot of air and draw a lot of power. If you're really worried about staying warm, get a propane space heater and a 20lb tank. It will be enough to keep a room or two warm for a couple days.

Get a thermopile and Millivolt gas valve

[deeptrace]

You can run a gas furnace off of the heat generated from the pilot light using a thermopile and a millivolt controller gas valve. I have heated my house this way in the middle of winter over a 3 day ice storm blackout.

It must be a hot water system. Just open all of the zone valves and eventually the whole system will heat up to the furnace temperature via convection in the pipes. The furnace will cycle between its low and high temperature, even with no power except the thermopile.

This is a standard type of system in the US. Not sure about the UK.

See http://hearth.com/what/gas/howgasworks.html for info on millivolt gas systems.

Power supply interruptions are NOT likley!

[kragwad]

"However, the UK press have recently been warning that power supply interruptions are likely this winter "

Get your facts right. I don't know what coverage you're reading (the tabloid papers I suspect) but there is no power supply crisis forcast for this winter.

What has been commented on is our increasing reliance on imported power from the continent, and coupled with the decommissiong of several major nuclear power plants over the next decade if we don't act now there could be problems in the future. I don't think UPS'ing your heating system is necessary just yet :)

"But the government said the outlook for power supplies this winter was good and accused the union of "scaremongering""

Source: http://news.bbc.co.uk/1/hi/business/3751810.stm

VRLA = Valve Regulated Lead Acid

[SuperBanana]

I'm not familiar with what "VRLA" means, but unless the battery is sealed gel-type and rated for deep discharge and repeated cycling, I'd wouldn't use it.

VRLA is Valve Regulated Lead Acid...VRLA is better than a sealed lead acid precisely because it will NOT explode- it will vent if charged too fast.

VRLA is a teensy bit different from a standard gel cell in terms of charge profile, but they're close enough that it shouldn't matter much; I think the float voltage is typically lower. HOWEVER, you DO need to make sure you match specifications ( and not just "12v", get the specs sheet and look at the charge, float, etc voltages), and be aware that VRLAs are not particularly fond of heat; adding a tiny fan to the UPS enclosure would probably be a swell idea anyway as the buggers tend to run hot.

The REALLY thorough will check the charge current from the UPS. UPS makers are under pressure to get the battery charged back up quickly, and they may push the limits of the battery's charge current. It's generally C/20 where C = A/Hr capacity; ie a 20Ahr battery should not be charged faster than 1A continuous (a brief peak charge might be OK, and if so, will be specified in current and duration). Charging too fast will cause gassing, overheating- and past a certain point, like many other batteries, lead acid batteries of any type can go into thermal runaway, which is not pretty.

Adding in extra batteries into a UPS not designed for expansion will be trouble, on the charging side of the equation. If you've ever had a completely dead car battery and tried to charge it with a charger, you know what I'm talking about- the voltage drop is so great, the battery practically acts like a short and will cause the charger to overload. The same thing could happen with a UPS. A good sign is if there are battery expansion packs available for your UPS; use that as a guide for sizing.

Oh, and by the way, you may want to consider adjusting your UPS to use the proper float voltage (not for the faint of heart, but possible on some UPS's without soldering), and again, installing a low-speed fan to move some air through the thing and keep everything cool. Many UPS vendors coughAPCcough set their float voltages too high and thus cook the batteries, and the elevated temperatures don't help either; that all makes for a nice revenue stream, as they charge a fortune for replacement packs(which are almost always made up of standard-size batteries, and thus available much more cheaply if you're the enterprising type). Properly maintained lead-acid batteries should last almost a decade- yet most UPS batteries die within a matter of 2-3 years. It's pathetic, considering how much lead is in them and how most people probably don't dispose of the UPS's or the batteries properly.

Re:How cold does it get in the UK during winter?

[NtroP]

Heh, OK, I just can't let this opportunity pass (mostly because I have enough anti-freeze in my blood right now to not know when to STFU :-)

I live in North Pole, Alaska (yeah, really) and I've seen it get to -70F (-57C) here a few times. I've actually saved myself from freezing to death by crawling under the hood of my truck to lay on the [rapidly cooling] engine when my belts snapped with the cold. I now make it a rule that I call in sick if it drops below -55F.

In my experience, it takes a long time for pipes to freeze to the point where they burst. The power goes out a lot here (I have 3 APC 1100 UPS's under my desk to keep my computers and peripherals up during the black/brown-outs). Granted my house has 12" walls, but I've seen the power go out in the dead of winter here and, 12 hours later, the house might be down to around 40F. I do not run glycol in in my heating system, but I DO let the faucets drip (slowly) whenever it looks like it's going to be a long outage.

Now, I have considered getting a generator (a lot of people have them around here), and it would probably be a good idea. But in leu of that, [we] have a rather impressive set of winter gear that we can rely on - my parka has build-in, replaceable 8-hour chemical heaters under each arm and my "bunny-boots" could probably have kept the astronauts toasty on the moon.

That being said, I'd have to echo the parent post about finding the chicks. It's usually best to have the wife and kids spend a nice warm night in a hotel though, before you invite said chicks over to help you survive.