Candlelights/ electric light bulbs - energy conservation?

[profloater]

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.

I can see both those points but we do use candles at home just for effect and we have no trace of soot on the ceiling even after many hours of candle light in the same spot.

[profloater]

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.

I am sure it will only be a few more years before nearly all lighting from automobiles to houses and stage lighting will be from led. All these applications are in use right now and the energy saving and long life are bound to triumph. These high power leds are amazing and the lamp colour is also much better than any fluorescent lamp, indeed it is multicoloured where needed.

[swampyankee]

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.

As I said, one of the contractual conditions for living in the dorms is that they give the school the right to inspect their rooms without notice. Nonetheless, I'm sure that there are a few candles in my daughter's dorm.

[Ivan Viehoff]

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?

This is completely ridiculous. A 40W lightbulb for one hour uses 0.04 kWh of electricity. At typical electricity prices that costs rather less than $0.01. You don't get one-hour-worth of candle-light for anything near that price. You might argue that they are willing to "save the planet" by using an expensive energy form, if only it is less energy. But electric light was such an advance precisely because it was such a more efficient way of converting energy to light than burning wicks. Candle wax is an expensive energy source, you can get camp lights that run off cheaper fossil fuel energy sources, such as gas and petrol lights. And if money is not important to you, then I have a 2W LED light as my bedroom reading light, must be incredibly more efficient.

If you do have to use candles, and want to see better with them to read, make lanterns out of drinks cans for them. You cut out about a quarter of the side of the can, and put the candle inside. The reflective surfaces inside the can concentrate the light so it is much brighter where you require it. Try not to cut yourself with the sharp cut edges of the can (says he from recollection of the last power cut).

[NEOWatcher]

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

Not necessarily. From wiki uses of paraffin (with burning uses in strike-out):

Candle-making
Coatings for waxed paper or cloth
Shiny coating used in candy-making; although edible, it is nondigestible, passing right through the body without being broken down
Coating for many kinds of hard cheese, like Edam cheese
Sealant for jars, cans, and bottles
Chewing gum additive
Investment casting
Anti-caking agent, moisture repellent, and dustbinding coatings for fertilizers
Agent for preparation of specimens for histology
Bullet lubricant – with other ingredients, such as olive oil and beeswax
Crayons
Solid propellant for hybrid rocket motors
Component of surfwax, used for grip on surfboards in surfing
Component of glide wax, used on skis and snowboards
Friction-reducer, for use on handrails and cement ledges, commonly used in skateboarding
Ink. Used as the basis for solid ink different color blocks of wax for thermal printers. The wax is melted and then sprayed on the paper producing images with a shiny surface
Microwax[19]: food additive, a glazing agent with E number E905
Forensics aid: the nitrate test uses paraffin wax to detect nitrates and nitrites on the hand of a shooting suspect
Antiozonant agents: blends of paraffin and micro waxes are used in rubber compounds to prevent cracking of the rubber; the admixture of wax migrates to the surface of the product and forms a protective layer. The layer can also act as a release agent, helping the product separate from its mould.[20]
Mechanical thermostats and actuators, as an expansion medium for activating such devices[14]
"Potting" guitar pickups, which reduces microphonic feedback caused from the subtle movements of the pole pieces
"Potting" of local oscillator coils to prevent microphonic frequency modulation in low end FM radios.
Wax baths for beauty and therapy purposes
Thickening agent in many Paintballs, as used by Crayola
An effective, although comedogenic, moisturiser in toiletries and cosmetics such as Vaseline
Prevents oxidation on the surface of polished steel and iron

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.

But; what about molding, shipping, packaging? They all use up energy as opposed to bulk shipments.

[Gillianren]

As I said, one of the contractual conditions for living in the dorms is that they give the school the right to inspect their rooms without notice. Nonetheless, I'm sure that there are a few candles in my daughter's dorm.

At my alma mater, there are probably a hundred or more dorm rooms. Unless they're patrolling on a very regular basis, they're simply not likely to catch most candle use.

[DoggerDan]

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

A candle radiates roughly 13 lumens. A 23 watt (100 W incandescent equivalent) compact fluorescent lamp emits about 1,500 lumens, so I can't see how comparing them would be a reasonable comparison. Furthermore, I'm reasonably sure it takes significantly more energy to melt the wax in a typical 1-hour candle than it takes to power a 13 Watt CFL bulb that produces 65 times the light of the candle. Thus, the carbon footprint of reading by a single candle is much greater than the carbon footprint of reading by a 13W, or even a 23W CFL.

"Students," you say? Are they not teaching basic science at colleges and universities any more?

[swampyankee]

At my alma mater, there are probably a hundred or more dorm rooms. Unless they're patrolling on a very regular basis, they're simply not likely to catch most candle use.

My younger daughter's current school probably has on the order of a thousand dorm rooms, as it has several thousand resident students; it also has periodic and random inspections (the latter have probably been eliminated by budget cuts). In any case, I suspect that the school has concluded that having a rule against candles (and lanterns, toasters, halogen lamps, and desk lamps with non-metallic shades), the amount of these will be reduced sufficiently so that they are not a threat to the entire dorm or even entire floor of the dorm. This will also reduce the school's liability if the rule is being actively enforced.

[BigDon]

amounts of mercury poisoning in fish, in water,

Hey G, sorry you got in trouble, but since you brought up the subject...

Recent advances in chemical assays have now allowed the source of nearly 80% of the mercury in Pacific Ocean fish to be pin pointed as coming from two discreet sources in San Francisco Bay. And, (the mining industry was really watching this one), the sources appear to be natural.

So there is talk of remediating this somehow. Sealing the two large patches with concrete would raise an entire poop storm of other issues unfortunately.

[TrAI]

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

I believe that most of the light in flames comes from the incandescence of tiny carbon particulates, so that when you are using fire for lighting you want less than optimal mixing so that only part of the fuel is converted to CO2. If it was burned at maximum efficiency, you would only have a dim, bluish flame, like the one a gas torch with a mixing head has, and if you want the benefits that are gained by more efficient mixing, you need to have some other incandescent matter in your lamp.

Research on this during the latter part of the 1800s lead to the development of the thorium dioxide-cerium dioxide incandescent mantle, and though the electric light eventually out-competed gas lighting, incandescent mantles became popular for use in portable light sources.

[NEOWatcher]

... incandescent mantles became popular for use in portable light sources.

That's an interesting little factoid for me since it shows that I never understood what the mantle was for.
We had gas lights in our backyard when I was growing up, and I only saw mantles in outdoor lights or lanterns. I had always assumed it was to keep them from blowing out.

Just another one of those assumptions that sound so simple that there's never even a second thought.

[Extravoice]

Recent advances in chemical assays have now allowed the source of nearly 80% of the mercury in Pacific Ocean fish to be pin pointed as coming from two discreet sources in San Francisco Bay. And, (the mining industry was really watching this one), the sources appear to be natural.

Don, do you have any citations? This sounds intriguing, but a quick Google search didn't turn up anything.

[BigDon]

Don, do you have any citations? This sounds intriguing, but a quick Google search didn't turn up anything.

I may have read that one on PhysOrg. That sounds about right. If not there, either SFGate or Science Daily.

(Not having a specific bedtime I tend to wander all over the 'net in all kinds of mental states.)