Water heaters - isn't there a better way to make water hot?? Topic is solved

[Downunder35m]

My friend's hot water system ruptured with a nice band a few nights ago.
Was about 20 years old, so no big loss.
But when went for a quick visit today I was suprised to find the exact same old tank with gas burner underneath as before.
This time in stainless steel and deemed more energy efficient...

I like to play with things other people won't.
And of course I know that in other countries we find things like mini "power plants" that combine heating, hot water and cooling in one single unit with great efficiency due to "recycling" waste heat from where it is produced in a home.
But I can't see this ever becoming a standard in Australia.

So I played around a bit with my old induction heater circuit trying to harden a chisel when I realised how much hot water that thing produces while I heat the steel.
Considering I was only powering it with about 250W and made some steel glow as well I started to wonder...
We use pipes and water cooling because it is so much cheaper than creating a suitable coil using Litz wire.
For the power level required for industrial applications a coil would costs hundreds of Dollars just for the Litz wire, not to mention the problem to insulate the coil from the heat.
But as said, it got me thinking....
Protecting some mild steel from the corrosion cuased by water isn't that hard these days with modern technologies like ceramic nano coating.
What works great for a frying pan certainly works equally well for other purposes.

What if???
A question most inventors ask themself a lot of times....
I asked myself: what if you would try to build a high frequency water transformer....
A powerful enough Litz wire coild can be salvaged together with all required electronics from a cheap induction cooktop in the $50 range.
If not fully resin encased,like many of cheap ones are it is relatively easy to unwind the coil.
Problem is these cheap electronics do checks to make sure the the switching mosfets won't hang or or burn out when the required fequency can't be matched.
But funny enough it is relatively easy to measure the inductivity of the coil with and without a proper pot.
Same for the operating frequency range.
How hard can it be to wind this coil as a cylinder with a single layer and to match the required inductivity by providing "pot core" made from steel?
Would be total waste and only make the entire thing get glowing hot far too quickly, I know...
5 minutes of fun until all goes up in smoke.
But.....
If we would create this pot core with lots of channels and keep the material thin enough we could pump water through it....
But inlike the induction heater used in the industry we would "waste" all the energy into the water cooling system....
Should be just a matter of finding the right balance between core design and water flow rate.....

I don't have a 3D printer capable to print with steel but if I would.....
Shouldn't it be possible to cheat here?
Like by machining an inner core with lots of holes going through and steel pipes connting either end like a nice bird cage?
The magnetic fields would follow the paths provided and should get bloddy damn hot very quickly.
Any thoughts or ideas on this?

[Orngrimm]

In europe solar collectors for home use are super popular due to their very high efficiency (Solar to energy in water) and are sometimes even valveless and/or pumpless.
They are often made of evacuated tubes and are fully modular:

You just plug them into a socket which is containing your liquid to be heated (Water propably as well) and you can just pull the energy out no problem.

You can even use it to heat your air (like in garage during wintertime) like

[Downunder35m]

I know
Same for these great solar oven type tube systems capable of melting salt.
But I was more think the tradional way with quick hot water on demand.
So far we use gas or electricity on on demand heaters, usually with rather insane kW ratings.
Both are not really that efficient despite their energy star rating if you take who much energy is required per liter when it comes to higher volumes.
I would love to do some small scale test on an induction system for hot water but this damnlockown and the delays for shippments already drive insane.
Will have to wait until life in this country is back to something more normal.

[liquidhandwash]

Ive always wondered if you could turn a microwave oven into a water heater?

[Downunder35m]

Don't
I did and it is not great at all
Used a quartz tube going through the center of a stainless steel sphere - the garden deco kind.
Another hole for the magnetron's output "pipe".
Thought it might be a good idea to have both good shielding against the radiation and something to make the radiation bounce off and sooner or later hit the tube.
Some flex tubing and two glass marbles so the tube would act like these vintage "pumps" in coffee makers.
Theory was that the water gets hot, turns into steam and that the same action as in the coffe maker starts
Got a lot of steam after a few seconds but no movement or pumping action.
So simple did not work and I added a tiny pump to allow for controlled flow.
Kinda worked but with no real relation between flow rate and outlet temp.
Was always jumping between steam and not enough flow or luke warm at best.

I am certain a lot of the failures comes down to my quick and dirty approach!
On a second thought and now that you mentioned it:
The magnetron has no directed output, it is more like broad beam antenna pattern.
A feed horn could address that flaw to generate a radiation patter more like a real beam.
I have seen videos where people made water boil in the center of a glass like this.
We could then use a simple stainless steel tube with a plastic cap and side inlet/outlet.
The back plate of the tube would have to be slightly angled to prevent a direct reflection back into the magnetron - trust me you don't to repeat that I made when tried what happens
In such a configuration 100% of the mircowave energy would do directly into the water.
If I am not fully mistaken a tube of less than 20cm lenght would be enough to absord all energy so nothing would even reach the backing plate.
Don't have much stainless tubing left but might try one day just with copper instead.
Sound promising enough to give it another attempt....

[seattleuserfriendly]

Thank you for not calling these "hot water heaters." Hot water does not need to be heated. Those devices are "cold water heaters."

[Downunder35m]

Well it is more a thing of acceptance really....
If you go to a shop and ask for a cold water heater you are doomed to get at least very weird looks.
But if you ask for a hot water heater everyone seems to know what you really want
A bit of a conundrum like the "screwdriver"....
You don't drive a screw to get it it in, you turn it.
But did you ever ask in your hardware store for a phillips hed screw turner ? LOL

[seattleuserfriendly]

I march to the beat of a different accordion. I get chills each time I see a Baby Changing Station.

[Orngrimm]

Question was answered? See viewtopic.php?f=3&t=42