grumpyod wrote:
Is it possible to use a coil burner from a electric range? I have been trying to picture a roaster in my head using that as the heat source with its infinite control for temp. adjustment.

dja wrote:
they have a pretty slow lag time as far as changing temp goes I would think, where with a NiChrome coil they cool off almost instantly when the powers cut, But the lag time may not affect anyones profils except for a few people.

freshbeans wrote:
Perhaps with the coil in a very close-tolerance liner, drawing off the heat could work. I was planning on running at 8" column pressure before the RC anyway.
The Grump might have a winner!! -Scott

endlesscycles wrote:
A coil from a range is a viable heat source. Kw is Kw. Lag time will be greater than higher surface area options, but for smooth profiles (generally what you want, I've found), just fine. Once the sucker's heated up, drawing heat off it's thermal mass won't be too difficult... and may prove advantageous during the first two minutes.

danw2002 wrote:
Yes and no, you have to look at surface area, that is why air-blown type heaters have the very thin wire and lots of it, look at the coils i am using, they are very efficient at heat transfer to air, also look at an old baseboard heater, same kind of thing(most have a heat element surrounded by fins to transfer heat to the air), kind of like a car radiator....if fact very close to the same principals, surface area is key. stove coils are good for surface to direct surface conduction, not air to air, in fact some time try a fun little experiment, next time boil some water, time it with the pan on the burner, then put a little rack between them, say an inch or two, and time it now....big difference in time. but way to think outside the box. :Clap: stove coils would produce heat, and would prob. work, but how well and compared to other coils out there, that is a different story

endlesscycles wrote:
Well..turns out the controller is just a bimetallic thermostat. Probably better without it.

freshbeans wrote:


Let's just pretend I'm willing to work with the slow response time. Given the mass of the heat source, would a bi-metallic strip really be all that bad? -Scott

allenb wrote:

I once argued this same issue with Marshall over several posts and lost the argument.:|

Marshall is absolutely correct in his premise of watts in = watts out. Pretty much any configuration of element is forced to transfer its heat to the air otherwise the temperature of the element would continue to increase to the point of meltdown. In the case of the tubular stovetop element, the reason it's not used in most convection heating applications is that it's not economically practical, would be difficult to design around and the lag time mentioned before. Otherwise, there's no reason not to heat air with them.

Allen

danw2002 wrote:
i will leave it at this, take two rocks, same mass/weight. one is just one big one, the other is made of or a matrix of 300 equally sized small rocks with air passages between them all, both masses are heated to 500f all the way though to the core of all. now pass air though both masses at the same volume and speed, which mass will release the heat to the passing air faster?

greencardigan wrote:


My little brain hurts when i think about it, but this is how I see it.

The matrix of small rocks will initially result in higher air temps. But it will cool down quick. The air temp from the single big rock will start lower but after a some time will be warmer than the matrix.

I suspect it is related to the surface area and the surface temperature of the element. Two elements, same wattage, same airflow. One element with a large surface area the other with a small surface area.

The element with the larger surface area will have more air contact and will cool more easily resulting in a cooler surface temperature.

The element with less surface area will have a higher surface temperature to compensate for the reduced surface area.

Or maybe I'm completely wrong??

allenb wrote:


Dan, you mentioned the use of fins on baseboard heater elements. For others who may not know this, fins allow a couple of things to happen, one, to reduce surface temperature which is safer to operate especially in domestic use and increased service life of the element. Two, they produce a much increased natural upward convection draft.



Allen

allenb wrote:
...

What is the wattage of the hot plate tubular element?

Allen