Candlelights/ electric light bulbs - energy conservation?

[thecolorofash]

Some student where I live have taken to use candle lights in the evening to save energy /( electricity.) That had me thinking - how much energy goes into making a candle? Lets say a candle that can last one hour versus an 40W electric lightbulb turned on for one hour? Is this a good idea?

Best regards
Niels

[Hornblower]

If we were still making candles from beef byproducts we might be onto something. If I am not mistaken modern candle wax is made from petroleum, so I don't see energy savings. Unfortunately I have no information on the relative amounts of energy used here.

[Perikles]

It's a good question. My guess is that the electric bulb is far more efficient, both in terms of energy and cost. I hope these students are not studying physics.

[HenrikOlsen]

Paraffin is a byproduct of petroleum refining, if not burned as candles it'd be burned some other way.

Energy wise it's likely a net energy gain as they likely use less energy to produce that burning them gets you, but compared to burning the paraffin in a power plant and driving LED's on the electricity it's likely a loss.

[swampyankee]

Thanks! You've just given me a great idea for a homework problem....

[Perikles]

I have tried reading a book by candlelight, and it's very tiring on the eyes.

Wait: Students. Irrelevant.

[Hornblower]

When I was in college, I studied by candlelight for a history test during a power outage, and got an A on the test the next morning. My reading light was a single candle using an empty beer bottle as a candle holder. Yes, it was tiring.

[swampyankee]

When I was in college, I studied by candlelight for a history test during a power outage, and got an A on the test the next morning. My reading light was a single candle using an empty beer bottle as a candle holder. Yes, it was tiring.

Given the success of studying by candlelight, maybe we should forbid electricity (and electronics) in college dorms.

(hey, we've got one data point. Isn't that more than enough to draw a conclusion?)

[thecolorofash]

Thanks for the answers. I see now that the question is far more complex than I first anticipated. You have given me some keywords to further study this subject on the internet. Thanks

[profloater]

Using a quick estimate of about 42000 Joules per gram, a typical small candle (40 dia by 10 mm) gives out about 23 Joules per second compared with 40 Joules per second for a 40 watt lamp but a small fraction of the light output. Using two sig figures is not justified, apologies) but I wanted to do an order of mag calculation. The smart thing to do would be to convert to LED lights from a transformer, by far the most efficient light per unit electricity and having the ability to task light rather than the whole room too.

[Swift]

Given the success of studying by candlelight, maybe we should forbid electricity (and electronics) in college dorms.

Given the history of fires in college dorms, some with fatal consequences (one example), I think it a bad idea.

[korjik]

Given the history of fires in college dorms, some with fatal consequences (one example), I think it a bad idea.

why? they are only students.

[profloater]

It would be intersting to know whether candles cause more fires in student lodgings than overloaded electricity sockets/

[Gsquare]

When I was in college, I studied by candlelight for a history test during a power outage, and got an A on the test the next morning. My reading light was a single candle using an empty beer bottle as a candle holder. .

Entirely possible that "A" on the test was a result of the "empty" beer bottle.

G^2

[profloater]

Newton got an A for his treatise on how a candle works, beautiful paper , worth a read, of course he used daylight under apple trees for his revision.

[Swift]

It would be intersting to know whether candles cause more fires in student lodgings than overloaded electricity sockets/

Good question, but during my time volunteering on Brown (University) Emergency Medical Services I know of at least one fire in a dorm room caused by a candle that got knocked over (no injuries, but the room was pretty badly damaged). I also had a friend who overloaded their electrical circuit and only managed to blow the breaker for the floor they lived on (no fire).

[Van Rijn]

Given the history of fires in college dorms, some with fatal consequences (one example), I think it a bad idea.

Just what I was thinking. I have candles handy for a power outage, and have used them for that, but when I do, I always am a bit worried about causing a fire, and take extreme caution moving them or setting them somewhere. That makes it harder to use them as reading lights which they don't do well in any case. I now have a LED camp lamp ready as the main emergency lamp. I wouldn't think to use candles regularly for reading - the light is too poor and too dim.

Another issue is that the soot has to go somewhere, which means if you use a lot of candles regularly, you are going to have to clean and/or paint the walls more often unless you don't mind them getting sooty. There's an energy cost to that as well, not to mention the hassle. I'm not sure if breathing that stuff all the time is a good idea either.

[profloater]

trim the wick to eliminate soot, it is not a necessary byproduct. Candles and oil lamps can be really useful still and no need to be dangerous if you respect them. Halogen spotlights can ignite curtains! I've seen it happen.

[HenrikOlsen]

Trimming the wick won't eliminate soot, only minimize it. There are still particulate matter in the combustion products.

[profloater]

Trimming the wick won't eliminate soot, only minimize it. There are still particulate matter in the combustion products.

Very interesting is that always true? A gas flame can burn perfectly to CO2 ( CO also burns to CO2), why can't a candle?

[Van Rijn]

trim the wick to eliminate soot, it is not a necessary byproduct.

That's not true of any candles I've ever had.

Candles and oil lamps can be really useful still and no need to be dangerous if you respect them.

Conventional lighting is safer, and more useful.

Halogen spotlights can ignite curtains! I've seen it happen.

I don't use halogen spotlights. Most of my lighting is CFL, and I don't have to worry about what happens if I knock over any of my lights, get them too near paper, etc.

[Gsquare]

. Most of my lighting is CFL, and I don't have to worry about what happens if I knock over any of my lights,....

Yea, except for mercury poisoning ...well, I guess that's better than burning to death.

I'm stickin' with conventional incandescent bulbs...thank you Thomas Edison.

G^2

[swampyankee]

Given the history of fires in college dorms, some with fatal consequences (one example), I think it a bad idea.

I'll agree it's a bad idea. Where my daughter goes to school, they do not allow halogen lamps, and they require desk lamps to have metal shades. I believe no college dorm will allow open flames, such as candles, and one of the pieces of paper that students sign says that the school has a right to inspect their rooms for violations.

[HenrikOlsen]

Very interesting is that always true? A gas flame can burn perfectly to CO2 ( CO also burns to CO2), why can't a candle?

The ratio of carbon to hydrogen is higher in paraffin wax than in gas resulting in a lower temperature burn, plus there's less than optimal airflow.

[Hornblower]

Entirely possible that "A" on the test was a result of the "empty" beer bottle.

G^2

No, I did not drink the beer. I fished the bottle out of a wastebasket.

[Hornblower]

Back to the efficiency issue. This could be an interesting engineering thought exercise, using hypothetical conditions.

For the energy expended at the light source, I think there is no question that a tungsten lamp would deliver a higher percentage as light. With an LED it would be no contest. The light from a candle flame is mostly from incandescent carbon particles, at a much lower temperature than that of the tungsten filament.

The flip side is that the generation of electricity from a combustion engine turning a generator is nowhere near 100% efficient. It probably is way under 50%. We might break even with candles. Of course that does not eliminate the hazards. I would say no candles in the dorms and advise the students to have battery powered LED lamps for power outages.

[Van Rijn]

Yea, except for mercury poisoning ...well, I guess that's better than burning to death.

How would you get mercury poisoning? In the unlikely event a CFL breaks, the amount of released mercury is minimal and it's not in a particularly dangerous form. Breaking a mercury thermometer releases far more and that used to be a pretty common event. It happened in our house and it didn't bother anyone. Heck, I played with a fairly substantial amount of mercury in my High School chemistry lab (far more than was in a thermometer). It also used to be common to use mercurochrome on cuts, and I still have some in the house.

It's reasonable to minimize mercury exposure for long term health issues, but you aren't going to get mercury poisoning from CFLs unless maybe you deliberately break thousands of them in an enclosed space, and do everything to maximize your exposure. Eating tuna is probably a bigger risk.

I'm stickin' with conventional incandescent bulbs...thank you Thomas Edison.

If your power comes from coal, that means more mercury is going into the environment than if you used CFLs.

[Gsquare]

How would you get mercury poisoning? In the unlikely event a CFL breaks, the amount of released mercury is minimal and it's not in a particularly dangerous form.

Tell that to these guys.. http://www.science20.com/make_love_n..._concern-71812

If there wasn't a real risk of mercury poison why do you think the evironmental guys are warning everyone how clean up when you break one of those darn things...
http://blog.lightingbylux.com/2011/0...ing-cfl-bulbs/
More..
http://movement.lifespeclighting.com...Poisoning.html

Its amazing to me how the "green kooks" cry so much about tiny amounts of mercury poisoning in fish, in water, blah, blah and then hypocritically ignore the threat they want to force upon you right in your own home simply in the name of political correctness.
I resent being forced against my will because of some political correctness doctrine imposed upon Congress,,,,

No thanks.. I have loaded up with a truck load of conventional light bulbs just becuse I DO HAVE A CHOICE and I hope to tee these guys off.

By the way, I got a truck load real cheap...and I'll quadruple my money selling them when all the idiots realize what a dumb move they made paying 10 times over for a mercury poisoned bulb that rarely lasts 4 times as long... I know it will really upset the anti-capitalistic politically incorrect "save the world from capitalists - live off the government" slum dwellers.....but it will make me happy.. ha, ha.lol

By the way, I will heat my house in the winter with lots of light and heat from these wonderful incandecsant bulbs........at least I won't poison my kids ....and I have enough to last three lifetimes....

[Gillianren]

I'll agree it's a bad idea. Where my daughter goes to school, they do not allow halogen lamps, and they require desk lamps to have metal shades. I believe no college dorm will allow open flames, such as candles, and one of the pieces of paper that students sign says that the school has a right to inspect their rooms for violations.

They would have a very hard time enforcing that at my alma mater, so they don't even try. Candles and incense are not anywhere near as common at setting off fire alarms on campus as bad cooking.

[captain swoop]

Gsquare This is totaly inapproprate for BAUT. You know this as you have already had a suspension for something similar.