dave_j

It is a little misleading. It will run a radio, phone charger, DVD player (not the TV), internet router, a light or two depending on the bulb rating, electric tooth brushes and some things that use an electric motor.. but nothing that generates heat. So anything rated at 120W or less.

BristolUK

Thanks. I saw one review that said a laptop. So I could get a youtube clip of a kettle boiling then.

dave_j

It will run a laptop but not a desktop system. The power supply for the laptop I'm working on, an elderly HPG60, is rated at 65W. Typical desktops rate at 200W upwards depending on peripherals eg graphics cards, additional disc drives, cooling fans etc, installed.

If we want to use this device to do something useful then we need to consider some numbers.

If you could find a low power heater, rated at 120W or less, and you want to be able to heat a cup of water then...

If we completely ignore heat losses from hot containers and any heat that is used to heat containers themselves and if we cover the water to prevent evaporation then the following gives you some idea of what this device could ideally achieve.

120W means that the device will supply 120 Joules/sec. The calorie is defined as that amount of energy that will raise the temperature of 1 gr of water by 1C. There are about 4.2 Joules/calorie so 120W will increase the temperature of 120/4.2=28.5 gr of water by 1C/second. If we assume that the average cup holds 300 gr of water, then the temperature will increase by 28.5/300=0.095 C/sec. So to raise 300gr water from 5C to 80C will take (80-5)/0.095=789.5 second or about 13 minutes.

However, if you want to heat the water to boiling, it will take a further (100-80)/.095=210 seconds or a further 3.5 minutes. So the minimum time the device will take to heat 300g water from 5C to 100C will be 16.5 minutes.

If the water isn't covered then you run into another problem. The latent heat of evaporation of water is 2257 Joules/gr. What this means is that the device must work for an extra 2257/120=19 seconds for each gramme that evaporates.

It's likely in real life that as the container gets hotter you lose heat to the container and its surroundings and as some water evaporates from the surface then you might be looking at times in excess of 30 minutes to heat the water to 100C so I hope you're not thirsty when you start and if you have a friend then explain that you only have one cup.

I hope it's not dark, because you won't have any power left to light the bulb.

not2old

with your solution of any type of power back up, my suggestion to that folks is to always have something such as the following

http://www.walmart.ca/en/ip/coleman-.../6000189452829

http://www.walmart.ca/en/ip/coleman-.../6000039222089

BristolUK

@ dave_j

Are you my Physics teacher from Brislington Comprehensive?

Mr Hartnell? Told us a tale of a home made battery connected to a door handle to give a mild shock to his teacher.

paw339

It's certainly not clear advertising.

I think they are really talking about radios, CD players, tablet etc which require far less power than something that deliberately creates heat.

Howefamily

Wood insert. We heat the whole house with it and only rely on a heat pump for one room.

BristolUK

How do you handle the carbon monoxide?
That was back around 2007 and we've not used (nor needed) the woodstove since.
Last Winter we finally had a power outage of a significant length. Significant length in my experience here is 5 or 6 hours. Only the second one of that length and the first had been a line to our house rather than a general outage.

It was well into the evening when the power went and I decided to get hot water into a HW bottle for my bed and had an early night. The heating had been on, the house was warm and stayed warm enough until waking to find all restored.

Being in the city I feel this is as worse at gets - twice (once?) in 12 winters - but then even people not far from here were without power for at least a day in last winter's ice storm, so who knows.

Anyway, we don't know when the people before us last had the woodstove inspected and chimney cleaned, so for peace of mind I had it done today in case there should be occasion to use it.

The bad news is it was either installed not to code or the codes changed since.
It's well short of clearance distances from the internal walls, the flue isn't as it should be in behind and there is supposed to be 3 feet sticking out of the roof, not 2. The platform is fine except it's supposed to extend beyond the stove more than it does. Oh...and in the basement there is supposed to be a door in the base of the chimney rather than being "bunged up"

So there may be some implications for insurance. And, of course, safety.

To satisfy the distance codes the platform needs to come out so far into the room as to be more than a nuisance.

Apparently there are other woodstoves that don't require these distances but the cost of one and the other corrections would be $5k or $6k.

It's not worth doing.

I wonder about gas. Maybe a gas fire? Apparently the gas supply is already on the street.

Anyone had a full or partial conversion to gas with any experiences to share?

I don't want to go the whole hog, the Heat Pump system was all new only around 5 years ago.

Is it worth doing just for fire (assuming no electric ignition needed) and maybe hot water?

Who knows, with a gas fire I may reclaim the living room either side of winter.

bats

We replaced our wood stove with a free standing gas stove so when the hydro goes off we have heat but the fan on it doesn't work. We often put the gas stove on in the evening which means the living area is nice and warm but the bedrooms aren't too hot.

We had the gas supply put into the house, it cost nothing and there was minimal inconvenience.

Husband, the gas man, says it would be worthwhile. What kind if furnace do you have?

BristolUK

Sounds good, thanks.
I have a feeling it might be different here as not many are using gas yet and I remember reading - albeit some years ago - that start up costs were high.

That sounds a bit technical for me Bryant heat pump/air con system with electric heat back-up if outside unit isn't doing the trick.

bats

Do some calculations and see if a new HE gas furnace would be worth it. In Ontario it's a no brainer as you'd get your money back in two years.

dbd33

I've put gas into two of the last three houses (the other one already had a gas stove). The cost was minimal, how much escapes me but less than cheese and wine for a month.

BristolUK

I'm reluctant to replace so soon but a quick look at the Enbridge NB site says a typical annual cost for heat and hot water would be $1673. Going by how much above normal NB Power says we are that would be well above $2000.

We pay around $3300 a year but that gets air conditioning too. Probably not in the Enbridge figure.

I think I need more research - plus a reply from Enbridge.

Cheers.

MarkG

I've got some old bits of wood in the garage, and a big box of matches.

What I would like is a UPS that can run the furnace when the power goes out. It's crazy that the gas furnace can't run when there's no power, but we only get multi-hour power outages once or twice a winter, so I haven't been willing to invest the money yet.

dave_j

I bought a cheap secondhand 3kW generator for $200 and installed a fixed extension to outside where the generator runs, put plug and socket in line to furnace. Start generator, swap plug from mains to extension, heat-to-go ok.