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Author Topic: Peter Davey Heater  (Read 490611 times)

DOCV

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Re: Peter Davey Heater
« Reply #270 on: June 21, 2008, 12:48:14 AM »
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! :D
Hey Sprocket according to your last set of figures you're talking about a COP of 1.53.  When one gets figures like this it is time to get more serious about all the data.
Are you saying that :
Water Qty is 400ml
Start temp of water is 15 deg
End Temp is 100 deg
Time taken is 70 sec
And avg amps is 5.9 (start of 4 and end of 7.9)
If so COP is 1.53
Are you using a temperature guage on the water?

NerzhDishual

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Re: Peter Davey Heater
« Reply #271 on: June 21, 2008, 01:27:05 AM »

Hi guys,

Sorry for having disappeared. Very interresting posts...
I almost gave up but I'm motivated again..
------------------------------------------------
@EMdevices:
Yes, a COP about 1.5 (and tree times in a row!) would be interesting.
-----------------------------------------------
A couple of days ago (16/17 June), I tried other cups with thiner metal
"walls". I also tried to adjust the 2 cups distances or to build a device
with 2 similar cups. I have now almost 5 models of cups. I weighed my water
to check the accuracy of my measuring glass... Etc..
My results were discouraging with these new devices:  COPs between 0.81 and 0.91! :'(

The COPs are slightly underestimated because I do take into account the fact
that the cups are also heated. But a short calculation shows that, for
example, a 160 grams iron device is eqivalent to about 17 grams of water. Is it not?
----------------------------------------------------------
I also tried to make electrolysis with my cups, results:
No measurable gas with tap water. Bubbles appreared, but, obviously, my
plastic "cell" leak. Pictures to come.

With distilled water + baking soda:
12 volts DC bat.
Amps consumption:
Begin= 8.8 A  - End = 10 A.
2 min O6 sec = 0.25 liters
3 min 50 sec  = 0.5  liters.
(3600/(3*60 + 50)) *0.5 = 7.8 litres/hour

Changing the polarity of the cups.
Amps consumption:
40" = 12.8 A
2 min 10 sec = 12.20 A
2 min 45 sec = 0.5 liters >>> (3600/(2*60+45)) *0.5= 10.9 liters/hour.
3 min = 11.8 amps

The water heat!!! I do not expect to run a landmover with that! ;D
----------------------------
@Sprocket:
You gave me and idea! Distilled water.... Thanks. I will test that...
----------------------------
@Enki09: thanks for all your 'inputs'.
----------------------------

Best

storre

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Re: Peter Davey Heater
« Reply #272 on: June 21, 2008, 02:56:01 AM »
Attempting to take this up a level, so I sampled my inner bell's sound, found the fundamental frequency was pretty close to 1000Hz (933Hz), so ground it down till I got closer.  As you can see, not an ideal bell by any means, and hitting the magic 1000 proved illusive!  But I did look for effects between 990 -> 1010Hz with no success.  There's also a little soundfile attached - the bells sounds first, then a 1000Hz tone I generated for comparison.  As you can hear, (and see in pic.) they are pretty close.

So, question, am I right in thinking that 1000Hz is a harmonic of the 50Hz mains frequency?

(http://i288.photobucket.com/albums/ll190/Sprocket_06/DaveyBell_1000HZ_Sound.jpg)

The octave harmonics of 50Hz would be 100Hz, 200Hz, 400Hz, 800Hz, 1600Hz, 3200Hz, etc

I don't think it's the electricity that vibrates the bell but the electricity passing through the water at 60Hz having a 60Hz contraction expansion which is then aided by the bells also naturally vibrating at that same frequency. So it's the electricity to the water to the bell that the vibration propagates. The water becomes the hammer to the bell.

Sprocket

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Re: Peter Davey Heater
« Reply #273 on: June 21, 2008, 03:33:18 AM »
Hey Sprocket according to your last set of figures you're talking about a COP of 1.53.  When one gets figures like this it is time to get more serious about all the data.
Are you saying that :
Water Qty is 400ml
Start temp of water is 15 deg
End Temp is 100 deg
Time taken is 70 sec
And avg amps is 5.9 (start of 4 and end of 7.9)
If so COP is 1.53
Are you using a temperature guage on the water?

Make no mistake, I do not have a well-equipped lab here, so tend to err on the side of caution with regard to the measurments (ie. use max. rather than avg. current in calcs).  The 400mL is accurate, the start temp was current air temp at time of test, and the end boil-time taken from visual queues - vigorous boiling!

What does my kettle COP come to based on the measurments I posted?  If the COP is greater than 1, you will know my measurments are suspect! :D  Also, just did another test - different distilled water/baking soda solution, results were:

400mL distilled water @ 15 deg Celsius.
Start Current 1.8A, rising to 4.4A
Time taken to boil very vigourously 190 seconds

Personally, since I heard about "electrode boiler" (which is all this is) I have been looking for any info about the power Mr. Davey's device may have used, but can't find any!  Without some evidence that the power required was unexplainably small, we could well just be dealing with an electrode boiler here...

Sprocket

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Re: Peter Davey Heater
« Reply #274 on: June 21, 2008, 03:41:35 AM »
The octave harmonics of 50Hz would be 100Hz, 200Hz, 400Hz, 800Hz, 1600Hz, 3200Hz, etc

I don't think it's the electricity that vibrates the bell but the electricity passing through the water at 60Hz having a 60Hz contraction expansion which is then aided by the bells also naturally vibrating at that same frequency. So it's the electricity to the water to the bell that the vibration propagates. The water becomes the hammer to the bell.

Aha, thanks, that's what I needed to know!  Also sucks of course 'cos both 'bells' aren't suitable - small one 1000Hz, (after much work!) large one is about 825Hz...  Of course, it also means that there is a valid reason for it not having worked! :)

DOCV

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Re: Peter Davey Heater
« Reply #275 on: June 21, 2008, 10:46:43 AM »
Make no mistake, I do not have a well-equipped lab here, so tend to err on the side of caution with regard to the measurments (ie. use max. rather than avg. current in calcs).  The 400mL is accurate, the start temp was current air temp at time of test, and the end boil-time taken from visual queues - vigorous boiling!

What does my kettle COP come to based on the measurments I posted?  If the COP is greater than 1, you will know my measurments are suspect! :D  Also, just did another test - different distilled water/baking soda solution, results were:

400mL distilled water @ 15 deg Celsius.
Start Current 1.8A, rising to 4.4A
Time taken to boil very vigourously 190 seconds

Personally, since I heard about "electrode boiler" (which is all this is) I have been looking for any info about the power Mr. Davey's device may have used, but can't find any!  Without some evidence that the power required was unexplainably small, we could well just be dealing with an electrode boiler here...


Hey Sprocket
The COP on thisnew info is 1.07, but due to the quality of the variable data the scope for error is quite large.
The two criteria that is important is the start and end temp, which one needs a digital thermometer. The second is a watt meter. Without this you have to use voltage x amps. Because the amps are moving around and using a start and end amp rating and calculating the average is not quite correct but will give you a ball park wattage.
When one starts moving to ball parks in eccess of 1.5 COP, then more sophisticated equipment will be needed to verify the facts.
Also because a kettle has a 2000w rating does not mean its working at 100% efficiency so one cannot take this into your calcualtions. Rather place the ampmeter around the wires as kettle elements have a constant amp measurement.

As for harmonics of 50Hz they go up in multiples of 50, so 50 , 100, 150 , 200, 250 , 300, 350 etc...Not 50, 100, 200, 400, 800, 1600

storre

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Re: Peter Davey Heater
« Reply #276 on: June 21, 2008, 02:48:54 PM »
Aha, thanks, that's what I needed to know!  Also sucks of course 'cos both 'bells' aren't suitable - small one 1000Hz, (after much work!) large one is about 825Hz...  Of course, it also means that there is a valid reason for it not having worked! :)

I think only one bell needs to be tuned to an octave harmonic or the mains. The other just needs to be at the right distance from the tuned bell to act as a reflector of the waves.

I'm arriving at those frequencies by taking the octave of 50Hz which would be 100Hz then the octave of it which would be 200Hz etc. I think the octaves will be the strongest harmonics of the main but there will be 5th harmonics and others as well, especially when you get in the higher harmonics.

Paul-R

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Re: Peter Davey Heater
« Reply #277 on: June 21, 2008, 04:09:36 PM »
The octave harmonics of 50Hz would be 100Hz, 200Hz, 400Hz, 800Hz, 1600Hz, 3200Hz, etc
Don't forget that the USA users need to tune to these possibilities:
60, 120, 240, 480, 960 hz etc.
Paul.

Sprocket

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Re: Peter Davey Heater
« Reply #278 on: June 21, 2008, 07:40:47 PM »
There seems to be a disagreement of sorts on what multiple of the fundamental frequency should be used, a hugely important number imo, if only from the work point of view, as the bell will have to be ground down to this frequency...

Having got no positive results with 1000Hz, I tried reversing the connections, attaching the live to the outer bell, which is closer to the other untried 800Hz harmonic mentioned (bell is about 825Hz).  First little surprise was that the 'character' of the boil seems quite different, much 'smoother' - easier to witness than explain!  Results were:

Time to boil 225 seconds.
current was 1.9A at start rising progressively to max out at 3.2A

At this stage I'm starting to believe that all I really have here is an electrode boiler, so a COP close to 1 is all there is to be expected...

forest

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Re: Peter Davey Heater
« Reply #279 on: June 21, 2008, 09:24:28 PM »
DID YOU HEAR ANY 'BUZZ' SOUND !?

I didn't, and that worry me a lot... Without such sound I suspect only a typical immerse boiler

DOCV

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Re: Peter Davey Heater
« Reply #280 on: June 21, 2008, 10:22:26 PM »
I attached the live to the outside bell and got zero zipp nada. No amps not heat Just nothing. On the inside I got instant heat, amps etc..
Wonder what was happening as sprocket got something...

forest

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Re: Peter Davey Heater
« Reply #281 on: June 21, 2008, 10:37:29 PM »
I have a bit more complicated assembly with a threaded rod connected to the neutral and going throught outer and inner bell but connected electrically to outer bell while live wire is connected to inner bell. That threaded rod is ended with a metal cap.Neutral wire is also wrapped around outer bell a few times.

Unfortunately I have no fast heat or boiling action. Water just goes a little bit warmer but it took many minutes and 220V/0.4A which dropped to 0.2A at the end.

Nothing  interesting.

forest

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Re: Peter Davey Heater
« Reply #282 on: June 21, 2008, 10:39:39 PM »
I realized that my inner bell is mostly covered by black paint which is probably insulation so I must scrap it all and retest again. The problem is how to mount bells in such manner that allow them to vibrate and still be connected to power. Any wire connected to bells seems to reduce vibration a lot.

forest

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Re: Peter Davey Heater
« Reply #283 on: June 21, 2008, 11:05:57 PM »
Looking once again into video... Obviously that small hemispherical metalic objects laying on Davey tabletop are common because he has got so many. Why I can't find any ? Where can I buy a few such hemispheres ?

storre

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Re: Peter Davey Heater
« Reply #284 on: June 21, 2008, 11:35:27 PM »
I realized that my inner bell is mostly covered by black paint which is probably insulation so I must scrap it all and retest again. The problem is how to mount bells in such manner that allow them to vibrate and still be connected to power. Any wire connected to bells seems to reduce vibration a lot.

If you fasten the bell at it's top then it doesn't dampen the vibrations so you could use a teflon screw with it's center drilled out that would accept a metal screw which would connect to the inner bell. Connect the phase line to the top of that center bolt. The outer bell could have a nut welded to it so it can screw up and down the teflon bolt to adjust the spacing. The wire for the outer bell could be soldered to the nut to not dampen the vibrations.

You could also use a drilled out metal bolt if you put good insulation on the center bolt that will connect to the inner bell. In this case you could make both electrical connections at the top of the outer and inner screw.

The screw thread to adjust the distance could also be done so the inside of the teflon bolt would have the screw threads and the inner bolt would screw in and out of it to adjust the distance. The outer bell would be fixed to not move.

I will be trying one of these variation in the next couple of weeks. I found a friend that has access to a machine shop :)