Cavitation. The key to overunity?

[AbbaRue]

A water boiler already is a Faraday Cage so using a magnetron inside it wouldn't have that problem.
Also about the plasma type water heater mentioned earlier by "khabe":
The water line is what is used to ground your whole house wiring so you don't have to worry about getting shocked.
If the main ground to your house were broken the plasma heater in the water boiler would be your least worry.
Every tap in your house could be lethal if you touch it then.
The only way this could happen is if the water line going into your house actually broke off were it enters your house.
Then you wouldn't have any water running into your house.
So we could say the plasma water heater is about as safe as any electric heater could be.
Unless you have plastic water lines going to the water heater then it's a different story.
Then any type of electric water heater could be dangerous.

[sparks]

@CrazyFox

    This information is very interesting.  Intuition is telling me that somehow this process was employed by Tesla who would locate the oil filled capacitor discharged by the spark gap in a defined geometric relation to the gap.  The transverse waves emitted by the gap are definitely at ionizing intensities and their effect on the capacitor metals themselves bear investigation.

[spinner]

Thanks.  OK, here is what is probably a stupid question.  We can all heat water from ambient to boiling in less than a minute in our microwaves so.....has anyone looked at a microwave home water heater? 

Bill, this is certainly a very good (definitively not stupid!) question! Microwaves are primarily designed for heating water (!!!) â€" which is, btw, the main substance of (almost) all food.

How would the efficiency of this compare with the standard resistance heating method?  I realize the cup of water is very small compared to 50 gallons of water but, once it is heated initially, just like the old system, it would only take a few zaps now and again to maintain the temperature level.  Of course, it would need to be encased in a Faraday cage but, that should not be a large problem.
As I said, probably a stupid question but I have always wondered why this was never done commercially.
Bill

I think the power needed, overall energy efficiency and combined technical and safety problems are the main obstacle why we're not using high power microwave water heaters at the moment..

The common resistive element water heaters are by far the cheapest, less complicated, very reliable,... and when DESIGNED PROPERLY they still are the easyest way when it comes to wasting electricity for producing Heat.... After all, the calorimetric methods are built on it...

(considering the quality levels of energy sources / carriers, Electricity is considered as a High level of quality energy (one of the most »noble« and costly ones), while the heat is at the very bottom of that scale...
Yes, at the end of any energy conversion chain, there is only a heat (or cold)...)

Using Electricity for producing Heat is a kind of »blasphemy«...(LOL)). Would you agree?

So, efficiency problems (microwaves of any kind are somewhere at 50-70% (the best known) while the resistive ones are >95% (when designed properly!)).
Technical problems? OK, things like microwave leakage, very high voltages (proportionally raising with power for the magnetron which is really a »filthy« tube when it comes to unwanted EM radiation....), costly production, etc, etc...

Sorry, I haven't got any 'OU' time lately ( ),  but I want to say that I'm seriously thinking about @khabe's ion heater... I know the principle for a long time, but I once dismissed it as a very problematic (hazardous) one...
I'd like to ask him some questions about his excellent work/device.... I believe he made a very efficient heating system!  Even though it »wastes« electricity....

Cheers!

[spinner]

A water boiler already is a Faraday Cage so using a magnetron inside it wouldn't have that problem.
Also about the plasma type water heater mentioned earlier by "khabe":
The water line is what is used to ground your whole house wiring so you don't have to worry about getting shocked.
If the main ground to your house were broken the plasma heater in the water boiler would be your least worry.
Every tap in your house could be lethal if you touch it then.
The only way this could happen is if the water line going into your house actually broke off were it enters your house.
Then you wouldn't have any water running into your house.
So we could say the plasma water heater is about as safe as any electric heater could be.
Unless you have plastic water lines going to the water heater then it's a different story.
Then any type of electric water heater could be dangerous.

@AbbaRue,
Yes, the metal housing of the water heater is a good Faraday's cage for the microwaves... The shape/volume of the cavity can be designed to suit the needs of a proper microwave "resonator"... But there are other issues....

OK, direct electrode ("ION water heaters") -  a design, which is (as far as I know) not legal / forbidden in Europe(?), due to high safety risk involved...

The water line is what is used to ground your whole house wiring so you don't have to worry about getting shocked.
If the main ground to your house were broken the plasma heater in the water boiler would be your least worry.

The water is a fairly good conductor, but it's not "generally" used as a grounding method for the safety of electricity distribution...
The REAL ground/ earthing is used instead.. Depends on the method, the Earth or Neutral potential line is used.

You mentioned a scenario, when ion type heaters generally fail - even if the ground/earth connections are "death proved" at your location, the failure at a neutral line (broken distribution/ transformer line,..) may produce a fatal shock to the user of water installations....

At that moment, ones totally depending on a safety disconnect electronic circuits... And those gizmo's need a few milliseconds to react (to disconnect the"live" wires...).
An electric shock of a several megaJoules intensity is experienced to anyone using the water installation...

What's the outcome? If you're thick-skinned, no prob..
How about your kids?

[ramset]

Spinner
In defense to user Khabe
I think laws govern sales to the public [at least in USA]
if a very talented and extremely skilled person such as Khabe builds a heater in his own home, it should not be a problem[as long as there are no problems ]
   Chet