[Ayoob]

I saw the plans for a heat diffuser made out of metal nuts, bolts, and washers that hold three upside down flower pots nested together. The idea is you light a candle under the flower pots and nuts and bolts. The flame warms the steel bolt, nuts, and washers, and then diffuses the heat out to the clay flower pots.

The steel is supposed to get up to about 550 degrees, the clay pots to about 180. This is supposed to warm up a room a little bit.

I have a couple tea candles going under my homemade version right now and I can definitely say that the steel is hot, the clay pots warm/hot, so it's going as advertised.

But why would this warm up a room any differently than just burning a couple of candles in the room?

The candles weren't warming up the room for the first little while, as the steel and clay were absorbing the heat. The diffuser will continue to radiate heat after the candles go out, but the candles would have warmed the air earlier, so where's the benefit?

I made the little device already so this isn't about whether it works, it does. But was it a waste of time?

http://www.greenoptimistic.com/2008/11/ ... om-heater/

Mine's like that one but I couldn't get a bolt that would have fit inside the pots that was threaded all the way, so I went with a threaded rod that's sticking up about six inches through the bottom of the top pot. The whole piece of steel is very warm to the touch, all the way to the top. It's a half inch foot long piece of steel that's being warmed by the candles.

Anyway.

Any comments on this?

[Tanada]

<Not a physicist but this is a common sense question not a physics question. All the energy you get from burning a candle or using an incandescent bulb is placed in the room where it is burning. Without the diffuser most of it goes directly into the air and secondarily it is absorbed by walls, ceiling, floor, furniture and so on in the room.

What the diffuser does is concentrate that energy locally to give you a 'hot spot' that you can place near yourself to make you warmer, the total energy released remains the same. The energy released by the diffuser after it warms up and before it cools down after the candle is extinguished is exacty the same as the candle would release directly, but it is held in one spot for a longer period of time before being distributed around all the objects and surfaces in the room.

If you set it next to someone who wants to be warmer in the cold season then its not a waste of time, otherwise its just a fancy shade for your candle.

[ReverseEngineer]

The amount of BTUs or thermal energy one candle puts out is minimal, but if you concentrate it into a small area it makes that area warmer. So with a device like this, you make a nice personal heater. Certainly will not warm the whole house though.

Most of you live in climates where just some good clothing will keep you plenty warm. I live in a climate where the current temperature is 20 degrees below zero. FARENHEIT. No candle will keep you warm outside, no matter how you concentrate the heat, its just not enough energy.

Thing is at least if there is Snow around, you can insulate a small space just with the snow if need be. This is the principle of an Igloo or Snow Cave. With enough thickness, an Igloo doesn't go much below the freezing temp of water at 32 degrees, long as there is some source of heat inside. That source of heat is the human bodies in the igloo mostly. If you have some dried seal dung to burn, you can keep it a bit warmer than that. However, 4 people inside a small igloo will keep the ambient temperature in the low forties.

With good clothing and a good sleeping bag,you can make it thru the night even at temps as low as 60 below outside, long as your snow cave is deep enough and you have good personal insulation. Not a pleasant way to live of course, but its certainly been proved possible may times over.

For the typical house in middle latitudes? Gimmee a break. If it fall to 40 degrees in FL people think its cold and turn on the heat. 40 degrees is NOT cold, its positively TOASTY. Heck, 20 below is pretty warm. Its 50 below up in Healy tonight. They still have coal there though, so I think they will be OK for a while. Cold is not so bad as you think once you get used to dealing with it. Insulation, Shelter, these are the main things. The human body by its biological process generates substantial heat. The MAIN thing is having FUEL for that body to burn. FOOD. Give me enough food, give me a good sleeping bag, I could make it in 60 below temperatures in a snow cave on the North Slope with no candles at all. Its not about the cold. Its about the FOOD.

Reverse Engineer

[angrybill]

My first thoughts were layers. The more layers of clothing isolate the human body from cold elements. So apparent are for the clay pots stacked. I’m not so sure if the assembly of nuts and bolts are needed but the concept in is order. Maybe the nuts and bolts are a means of separation. Magnification of an original heat source which is greater than the origin is interesting. You may be on to something.
Bill

[Quinny]

It's not useless, but it's also not magnifying the heat source, simply avoiding dissipating the heat into the air.

[smallpoxgirl]

Without the diffuser, the hot air would layer out along the ceiling. The diffuser traps the heat at ground level where it can warm you. In tight spaces a candle can provide significant heat. It's often given as a way to warm a snow cave for example. In a room with 8 foot ceilings, the heat's all going to go where you aren't.

[kpeavey]

The steel and pottery serve the purpose of thermal mass. You can warm your hands on it where the energy from a candle on a table simply dissipates throughout the room. Once the mass reaches its maximum temperature, there is no practical gain in keeping the candle burning. It would radiate the same amount of heat as a candle on a table without the rig.

The same effect can be achieved by stacking some bricks around a candle. Wrap the bricks in a towel, you have a foot warmer.

Put a cup of water on top of this device, you might be able to make tea. Other than that, its a $30 gimmick, plus shipping.

[Pretorian]

I live in a climate where the current temperature is 20 degrees below zero. FARENHEIT.

Whom do you teach math at $75 an hour if you don't mind me asking. Polar bears?

[Niagara]

The total thermal energy supplied by the candle is still the same, this has already been discussed.

But one thing the clay pots will do is cause a wavelength shift. The heated pots will radiate longwave infrared which will be perceived as warmth if you're sitting nearby.

Radiant IR heaters work this way. They heat *you* directly instead of the surrounding air.