Hot Water

[Donkey]

2 easy solutions to dangerously hot water:

1) PAY ATTENTION!! How about some awareness, a little uncommon sense and some care?? Test the temperature before you step into the shower/do dishes and adjust the tap accordingly! Teach your children to NEVER ASSUME and to pay attention as well!

2) Install a thermostatic mixing valve. Automatic heat adjustment at the source alleviates your responsibility for the safety of others and protects a somnolent public..


Legionella!! This particular heater should help with that issue because you can get it crazy hot without fear of over-doing it and blowing yourself up.

Incidentally, legionella is one of those bacterium that is EVER present. It tends to effect people with weakened immune systems and the elderly (same same). Drinking water with legionella in it will NOT harm you as the bacterium will be destroyed by your gut. It is breathing water vapour with the bacterium in it that can infect.
As always, your BEST line of defence is education, awareness and good health.

[ronyon]

So how about an electric water heater tank inside a bell made of two stacked barrels? Much like Matts stacked blocks in 55 gallon drums but with a heater tank instead. Cut off the top of the water tank and also a 6" ring below that.
Cut a section out of the ring, use it as an"Inside coupling" between the tank and the lid.
Run your plumbing connections through the threaded holes in the tanks top.
Seal with silicon.
Now wrap the barrel stack in rockwool.
Exhaust out the bottom, gasses from the rocket entering about half way up?

Would the heat be too much for the barrels?

[Cramer]

Just a thought but the wasted space below the barrel could have an open archway and a cradle inside for wood storage. No sense wasting that space in my most humble opinion. I was thinking of something very much like this for my build but with the buffer barrel on it's side. My thought was that more surface area of the coil would then be subjected to the hotter water stratified at the top edge of the buffer barrel. Great design, very self contained and it could process many gallons of water which could then be stored in large insulated tanks for mass. Safe too, the main concern when heating water with solid fuel.

[wrekinwanderer]

Thanks for the details Donkey.

What do you think is the minimum space needed around the hot water tank and the sides of the bell?

Also possible to simplify and reduce costs further by not bothering with a coil? Just have a longer cold feed pipe going into the base of the barrel and a small pipe taking the hot water out at the top. Of course it wouldn't offer the same level of legionella protection as the indirect system presented here.

However personally I think legionella risk is exaggerated. But then I do have a very laissez faire attitude to health risks, fostered by having an old skool doctor as a father! All the outbreaks to note have been in institutions. Hospitals, hotels, mostly air conditioning and cool towers mostly to blame here:

en.wikipedia.org/wiki/List_of_Legionnaires%27_disease_outbreaks

www.hcinfo.com/legionnaires-disease/outbreaks/70-outbreaks...

Has there ever been an outbreak in a private residence with a small volume of water? Or is that just a reporting bias? Or undiagnosed?

[furni]

Hot Water.   I wanted to do a passive way to heat a water barrel instead of a Cob Bench. I've built a thermosyphon system with the heat exchanger mounted to the bottom of the barrel. The bottom of my barrel averages 230f and the operating perameters of the heat exchanger says 241f. I would imagine to not melt the solder joints.

 It's worthless! After a 4 hour burn and a hot one at that, I only got a dribble out of the tube back into the tank. I'm going to go to an active, yet open system in order to heat this tank of water. I'll build a plenum to put on the top of the barrel, high enough to keep out of extreme temps and place the heat exchanger on top of the plenum. Also will have airspace to promote air movement through the coils. But since I don't want the tank any higher than it is ( I intend to cob all around it) I will have to use
a hot water pump, which I found online at Amazon.

[furni]

OK, I fixed it. Took out the heat exchanger and coiled 30 feet of 3/8 tubing around the barrel. Then wrapped aluminum flashing around the coiled copper. Now it's almost a constant stream of really HOT water. No pumps, no nothing. Just natural thermosyphon. I like it so far.

[Dan (Upstate NY, USA)]

Can we see some pics furni... please?

[2tranceform]

Jan 28, 2014 13:09:35 GMT -8 Dan (Upstate NY, USA) said:

Can we see some pics furni... please?

^^^^X2

[furni]

Well,alrighty then.

 I was going to wait until I tidied it up to post a pic. It's ugly cuz I did it on a HOT stove. When it cools down, I'll re wrap the copper and get it tighter to the barrel....same with the aluminum.
 I had concerns about holding in barrel temp with the aluminum and slowing down the rocket. No problems and a side note, the whole heater got hotter than it ever has. My top of barrel went up to 800f and I had never gone above 700f.

 After about 3hours the water had risen 35 degrees. Started at 40f. I know the water in the tank will stratify but this was a promising test for me.


coil.jpg 294.79 KB Error: This forum has exceeded its attachment space limit. Your file cannot be uploaded.

[furni]

I've resised down to nothing and it won't let me attach.

[2tranceform]

Jan 28, 2014 14:04:02 GMT -8 furni said:

I've resised down to nothing and it won't let me attach.

Link to the photo by using some sort of hosting service (photobucket.com or similar).

[furni]

I'll try to sign up at photobucket.

[furni]

i988.photobucket.com/albums/af6/davisfurni/coil_zpse04ba289.jpg

[furni]

It's all cleaned up and tidy.

i988.photobucket.com/albums/af6/davisfurni/1d6477de-ce6e-44ad-b01a-bb3d3481fc63_zpsee10fa88.jpg

[ga2500ev]

Jan 27, 2014 14:20:28 GMT -8 wrekinwanderer said:

Thanks for the details Donkey.

What do you think is the minimum space needed around the hot water tank and the sides of the bell?

The bell has to be large enough to slow the gases to the point where they stratify by heat. I believe I saw a number that was 5-10 times the cross sectional area (CSA) of the heat riser. So a 6 in round riser has 28 in^2 of CSA. 5 times that is 140 in^2. a 55 gallon drum is a bit less that 24 in across. The CSA is 452. So a square with a CSA of 452+140 = 592. 25 inches on a side will handle that.

Also possible to simplify and reduce costs further by not bothering with a coil? Just have a longer cold feed pipe going into the base of the barrel and a small pipe taking the hot water out at the top. Of course it wouldn't offer the same level of legionella protection as the indirect system presented here.

NO!!!! This has nothing to do with the bacteria. The domestic water supply is under pressure. And heating it puts it under more pressure. Pressure that a 55 gallon barrel isn't designed to handle. In short, without the buffer tank the whole setup can go BOOM!!!

Standard water heaters usually do not explode for 3 reasons:

1. The tanks are designed for the pressure.

2. Tanks have relief valves to relieve excess pressure.

3. Heaters have multiple systems to ensure that the water isn't heated beyond design temp.

Donkey's setup is safe for different reasons:

1. The water in the tank isn't under pressure.

2. Because of this the water cannot get any hotter than 212F.

3. Because the water in the coil is under pressure, it will not boil at 212F.

4. So the water in the coil will never boil and has no chance to explode.

The worst that can happen is that the water in the barrel boils off. But again since it's not contained the steam releases to the atmosphere.

Now if you heat the barrel directly as you have proposed:

1. The water in the barrel is under pressure.
2. The water can get hotter than 212F
3. The pressure can exceed the rating of the barrel.
4. BOOM!

So please do not try to take any shortcuts with the setup. Not having the open buffer tank severely degrades the safety of the system.

ga2500ev