Peter Davey Heater

[Sprocket]

Hi sprocket then all I need is a starting temp to give you a basic COP

Air temp atm is 15 Celcius, which sounds about right.

Doing a quick comparasion between my last results and my kettle results doesn't inspire confidence (assuming my rough calculation is ok)

1.7L tap-water => avg power required = 2,000W * 320 secs (time to boil) = 640,000 joules.
400mL Distilled water => avg power required = (Avg Current) 4A * 230V (AC mains) *  150 (time to boil) = 138,000
Adjusting for different amounts of water => 138,000 * 1700 / 400 = 586,500 joules

640,000 versus 586,000 - Not a big difference...

Out of curiousity, I have just boiled the same 400mL of distilled water, then 400mL of tap-water in the kettle - both took 89 seconds.

400mL distilled water => 2000 * 89 sec = 178,000 joules

So, it is about 29% more efficient than my clapped-out kettle.

Finally, seeing that the currents being drawn are fairly low, I chanced boiling 400mL of tap-water with my Davey heater, with meter attached.  Time taken was 70 seconds.  Current starts at 4A, raises steadily, maxing at 7.8A on meter before falling to between 5.5-6.5A when boiling.  There is a lot of fluctuation in current, in sync with the bubbles being produced.

400mL tap-water => 7.8 * 230 * 70 = 125580 joules

The higher conductivity of my (crappy) tap-water seems to improve efficiency (42%) relative to my kettle.

All assuming my math is correct!

[enki09]

I was doing this like 5 years ago and posting about it on this list and others. It is very simple and commercial versions of this type of device are called "Electrode Boilers" (google it).

The way I did it was to put two stainless electrodes in a jar of pure water and then add maybe 5 or 6 drops of an electrolyte like NaOH or H2SO4. I hooked the electrodes up to standard 110v wall socket power and to ground. I could boil a quart of water in 60 seconds with virtually zero current through the jar.

Theory is that the ac wave causes the water molecules to spin around really fast and the heat energy produced is then due to friction between the atoms as they spin.

[Sprocket]

I was doing this like 5 years ago and posting about it on this list and others. It is very simple and commercial versions of this type of device are called "Electrode Boilers" (google it).

The way I did it was to put two stainless electrodes in a jar of pure water and then add maybe 5 or 6 drops of an electrolyte like NaOH or H2SO4. I hooked the electrodes up to standard 110v wall socket power and to ground. I could boil a quart of water in 60 seconds with virtually zero current through the jar.

Theory is that the ac wave causes the water molecules to spin around really fast and the heat energy produced is then due to friction between the atoms as they spin.

Damn, I wish you had posted this about a week ago - when I think of all the kettles of water I have boiled needlessly in the last few days

Never heard of them (and I expect most here have neither) and their 99.9% efficiency would account for the decrepencies I am seeing between results.  But, I don't understand what you mean by "zero current through the jar" - electrode boilers are just very efficient, they'd be OU with zero current...

Back to Mr. Davey - is there any documentation etc. that states what power his heaters were proported to run at - I have seen nothing about this.  It seems to me like it could have been an electrode boiler...

[enki09]

Without any electrolyte in the cells it took longer to boil. With just a bit it worked really well. But that was AC not DC current and there seemed to be a tiny bit of electrolysis going on but this isn't verified. There were tiny streams of bubbles coming from the sharp corner points of my flat, stainless electrodes. However these bubbles could have been due to boiling of the water at those points. I say this because the electromagnetic lines of force are most concentrated at such sharp points and the heating effect could have been most rapid at these points.

Yes, I think they Davey thing is just an electrode boiler because it seems to fit the description and the results are what would be expected from one.

[enki09]

Just another comment on your reply. Even if there were zero current through the cell it would not be OU. Why? Because you have to take into account the energy that is required to keep the 60hz signal from the AC line pulsing through the cell. You can do some really wild stuff with water and magnets and electricity. I was doing a lot of active experimentation and recording it on my old website here:

http://www.geocities.com/mj_17870

Check out the "My Ideas" pages if you want. I have come a long way since then but it was fun.