Author Topic: Unlimited Off Grid Hot Water (Read 2177 times)

SeanJohnson · « **on:** July 02, 2022, 07:39:51 AM »

How to Build an Endless Hot Water System (Without Electricity)

by MICHAEL MAJOR

March 15, 2022

https://www.askaprepper.com/how-to-build-an-endless-hot-water-system-without-electricity/

The majority of today’s homes heat water with either electricity or natural gas. When we remove these from the equation, we discover the reality of how much energy it takes to heat water.
Placing a pot of water over a fire is a good method for heating some water, and you should absolutely do so whenever possible, but there is an easier DIY alternative.

How Does This Water Heater Work?
The off-grid water heater I detail here requires a wood-burning stove, and we are going to harness the heat energy that radiates off of it to warm up the water.

All that is needed is to build a run of copper pipe along the sides of your wood stove through which cold water will enter, and hot water will exit.
Since copper is such an amazing conductor of electricity and heat, the pipe will become heated and transfer that heat to the water inside. What this creates is an ‘on-demand’ hot water system.

The Wood Stove
Building your wood stove is not difficult as long as you have access to a welding machine, angle grinder, and a supply of steel.

I made a woodstove for this project out of an empty 20-pound propane tank that I had lying around.

If you do not have access to a welding machine, you can purchase wood stoves online.

Building a Wood Stove From a 20 Pound Propane Tank
Turning a propane tank into a wood stove is not difficult and requires only a few easily obtained materials to build.
Unfortunately, there is no way to accomplish this build without using a welding machine, angle grinder, and an oxy/acetylene cutting torch or plasma cutter.

These tools also require some skill to use, and many safety considerations need to be taken.

Instructions
1. Empty the propane cylinder and thoroughly clean it inside and out. Be sure that all the liquid propane is removed before proceeding further.
2. Remove the rings at the top and bottom and remove all the paint from the tank’s exterior.
3. Lay out and cut the opening for the door. Make the opening large enough to load wood into the stove comfortably.
4. Save the piece that you cut out to fabricate the door.
5. Secure this piece to the rest of the woodstove with a section of piano hinge. Add a handle at the same time.
6. Fabricate a base from the 1x1x1/8 angle. I chose to make it 12 inches square.
7. Cut four legs on a slight angle so that they will slope upwards to join with the cylinder.
8. Weld the base frame onto the stove body.
9. Cut a hole in the top to accommodate the four-inch stove pipe.
10. Slide the stovepipe into the hole and weld it in place.
11. Cut some expanded metal to the inside diameter of the wood stove and place it inside the stove.

The Heater
How you run the pipe will depend on your woodstove’s shape, but the basic principles are the same.

What we are trying to do is snake the pipe along the side of the woodstove to get as much pipe as possible exposed to the heat. We can do this in two ways.
We can use pipe elbows to snake the pipe along the side of the stove, or we can use a coil of copper pipe and wrap it in a tight coil around the chimney of the woodstove.

The difference between these two methods is that there will be less heat from the chimney, and therefore the water will not be as hot.

However, since using the woodstove sides create hotter water, the risk of too much pressure is ever-present and needs to be accounted for.

Materials For A Side Mounted Heater
• Copper Pipe
• Copper 90-degree elbows
• NPT copper fittings

Instructions
1. Measure the height of the woodstove side that you want to place the heater on while figuring out how many vertical runs of pipe you will use.
2. Measure the height of the elbows and how far the pipe will fit inside of them. The difference between these dimensions multiplied by two is the length that will be subtracted from the heater’s height to figure out the cut size.
3. Cut enough small lengths of pipe to join the 90-degree elbows together. At the same time, cut the straight sections.
4. Cut two six-inch lengths of pipe for the inlet and outlet.
5. Trial fit all the components together.
6. Solder the 90-degree elbows together to form the 180 degree turns in the pipe run.
7. Layout the heater on the stove to check the fit.
8. Solder the joints together. Don’t forget to install the fittings on the inlet and outlet so you can connect the water supply.
9. Drill holes for bolts to hang the heater on the side of the stove.
10. Install bolts that are long enough to hang the heater on.
11. Insert the bolts into the holes and secure them on the inside of the stove with a nut.
12. If needed, use a piece of metal strapping to hold secure it only on one end so it can be easily lifted out of the way to remove or install the heater.

Using the Water Heater
There are a few options when it comes to operating this water heater.
The first is to use it as an on-demand type of system where you draw the coil’s water as needed to get hot water.
The problem is that there will be a buildup of pressure within the system, and you will need to have a pressure relief valve in the system.

My preference is to keep the coils removable so that you can quickly and simply install the heater on the stove when needed and remove it when not in use.

Harnessing the heat that a wood-burning stove emits is a great use of this radiant energy to provide us with heated water.

Being able to get hot water on demand is one of those comforts that will make a grid-down scenario a little bit more comfortable.

SimpleMan · « **Reply #1 on:** July 02, 2022, 09:05:51 AM »

"Building your wood stove is not difficult as long as you have access to a welding machine, angle grinder, and a supply of steel."

Am I the only one who sees the irony in this statement?

SeanJohnson · « **Reply #2 on:** July 02, 2022, 09:21:51 AM »

Quote from: SimpleMan on July 02, 2022, 09:05:51 AM

"Building your wood stove is not difficult as long as you have access to a welding machine, angle grinder, and a supply of steel."

Am I the only one who sees the irony in this statement?

Reminds me of a John Pinnette joke, where he’s making fun of Martha Stewart recipes for being too complicated:

”The first step is to get out your chestnut roasting pan?? Guess were not making that recipe today!”

But back to the article, I think most people would simply buy (or already have) a wood burning stove, if they’re prepping for off grid living, so no need to break out the welding machine😂

SimpleMan · « **Reply #3 on:** July 02, 2022, 09:26:20 AM »

Quote from: SeanJohnson on July 02, 2022, 09:21:51 AM

Reminds me of a John Pinnette joke, where he’s making fun of Martha Stewart recipes for being too complicated:

”The first step is to get out your chestnut roasting pan?? Guess were not making that recipe today!”

But back to the article, I think most people would simply buy (or already have) a wood burning stove, if they’re prepping for off grid living, so no need to break out the welding machine😂

Believe it or not, I thought of Martha Stewart when I read that line.

moneil · « **Reply #4 on:** July 02, 2022, 09:33:58 AM »

An interesting (and useful in a broad sense) concept, using an already available heat source to also provide heat for another purpose. For an example, milk leaves the cow at 101 degrees F and needs to be cooled down to 40 degrees F fairly quickly to avoid excessive bacteria growth. Some farms will have a heat exchanger where the 101 degree F milk passes through tubes adjacent to tubes carrying 50 degree F well water, cooling the milk and warming the water. The milk than goes to the refrigerated bulk tank to be further cooled to the required 40 degrees F and the water goes to a hot water tank to be further warmed to the necessary temperature for cleaning, but because of the initial heat exchange less energy is required to for these actions.

Back in the 1980’s a friend of mine built a house in western Washington State with a wood stove (used for cooking and heating) which also heated the water. The piping was internal (for a good reason) and the water fed into a well-insulated electric hot water tank. He could turn the thermostat on the tank down and as long as the stove put out sufficient hot water the tank would never turn on (and thus not use any electricity) and acted as a reservoir of hot water. In the warmer months when one wouldn’t want a wood stove heating up the house the hot water tank could kick in to heat the water. The good reason that the water piping was internal in the stove (and what seems inefficient about the presented design) is that with exposed piping on the outside of the stove a lot of heat would be lost to the atmosphere.

Ladislaus · « **Reply #5 on:** July 02, 2022, 11:29:09 AM »

Quote

Building your wood stove is not difficult as long as you have access to a welding machine, angle grinder, and a supply of steel.
... and an oxy/acetylene cutting torch or plasma cutter.

These tools also require some skill to use, and many safety considerations need to be taken.

Ladislaus · « **Reply #6 on:** July 02, 2022, 11:31:57 AM »

Also reminds me of modern car repairs. For all but the most basic tasks, you need specialized tools that would cost more to rent (if you can even rent them) than it would just to pay for the shop labor. With some cars, you can't even get to the spark plugs anymore without taking half the engine apart. Pretty much all I an do on most newer cars are oil changes and brakes.

Quo vadis Domine · « **Reply #7 on:** July 02, 2022, 12:22:08 PM »

Quote from: SeanJohnson on July 02, 2022, 09:21:51 AM

Reminds me of a John Pinnette joke, where he’s making fun of Martha Stewart recipes for being too complicated:

”The first step is to get out your chestnut roasting pan?? Guess were not making that recipe today!”

But back to the article, I think most people would simply buy (or already have) a wood burning stove, if they’re prepping for off grid living, so no need to break out the welding machine😂

I generally don’t like comedians, but John Pinnette was seriously funny!

moneil · « **Reply #8 on:** July 02, 2022, 12:58:24 PM »

Regarding building and repair projects that may require skills and certain equipment …

Several states have 2 year community colleges which, in addition to traditional liberal arts and science classes also offer vocational training. Their tuition is lower than 4 year universities and sometimes other trade schools and they may offer free or low cost admission for senior citizens.

Where I live in Washington State and being over age 60 I can register for any community college class for $4.00 per credit plus any lab fees. It is a class audit arrangement (no college credit is awarded) and I need to wait until after the 3^rd day of class to sign up – those paying full tuition are admitted first. I audited the EMT (emergency medical technician) class a couple of years ago and plan to take a welding class and lab, a Microsoft Access class, a greenhouse management class … I’m sure I’ll find other topics of interest.

An uncle who retired in San Mateo, California restored a Model A Ford (a tear-down-to-the-bare-frame endeavor). Though an electrical engineer and rather handy the project involved some skills he didn’t have experience with and tools he didn’t own. He enrolled in the auto body program at his local community college, got to bring the car into their shop, received training and coaching for the skills involved, and got to use their tools and equipment. I don’t know about today, but at the time (1990’s) the program was free for him.

So, for these kinds of DIY projects, looking into public community colleges or vocational schools might be a useful option.

Nadir · « **Reply #9 on:** July 02, 2022, 07:06:06 PM »

Nadir · « **Reply #10 on:** July 02, 2022, 07:09:38 PM »

[font=system-ui, -apple-system, BlinkMacSystemFont, .SFNSText-Regular, sans-serif]Above: Rayburn wood stove from the 1950’s has some wear and tear from age but is in lovely condition great for home or man cave has hot water heating as well do have some flue bits also [/font][/size][/color]

[font=system-ui, -apple-system, BlinkMacSystemFont, .SFNSText-Regular, sans-serif]This is a similar model (for sale at $1,500) to what we installed in our home in 1991. Very efficient. Cost us $300. [/font][/size][/color]

[font=system-ui, -apple-system, BlinkMacSystemFont, .SFNSText-Regular, sans-serif]At the time we were off-grip.[/font][/size][/color]

SeanJohnson · « **Reply #11 on:** July 02, 2022, 07:17:50 PM »

Awesome find; they don’t build them like that anymore!

I just had my Samsung 5 year-old refrigerator go out (freezer side worked; fridge didn’t).

So bought new GE refrigerator 1 week ago.

Will it last 20 years? Very doubtful.

Bought super quiet Bosch dishwasher 4 years ago so my autistic boy didn’t freak out from white noise, and now it’s getting louder and performing poorer.

Meanwhile, my grandmother has a refrigerator in the basement from 1949 that still works flawlessly.

Believe all companies now only make crap as part of the great reset (ie., if you have to buy appliances and mechanicals of one kind or another every other year, it’s hard to save any money...which is the plan).

Nadir · « **Reply #12 on:** July 02, 2022, 10:46:22 PM »

This is the closest image I could find to our previous stove, during the 1980's. We were told about it, that it was lying out on a tobacco farm for years. It was rusty with a few smaller pieces missing and grass growing up through it. It cost us nothing except to find or make the missing bits and a good clean up.

No water heating though. That was achieved by laying a length of black polypipe above ground from the damn uphill down to the shower. Worked like a dream, but you had to time your showers according to the heat of the sun which was according to the time of day and the season.

The one pictured is for sale, second hand of course, for $2,200!

SeanJohnson · « **Reply #13 on:** July 02, 2022, 11:01:41 PM »

Quote from: Nadir on July 02, 2022, 10:46:22 PM

This is the closest image I could find to our previous stove, during the 1980's. We were told about it, that it was lying out on a tobacco farm for years. It was rusty with a few smaller pieces missing and grass growing up through it. It cost us nothing except to find or make the missing bits and a good clean up.

No water heating though. That was achieved by laying a length of black polypipe above ground from the damn uphill down to the shower. Worked like a dream, but you had to time your showers according to the heat of the sun which was according to the time of day and the season.

The one pictured is for sale, second hand of course, for $2,200!

A++

Nadir · « **Reply #14 on:** July 02, 2022, 11:44:27 PM »

Quote from: SeanJohnson on July 02, 2022, 07:17:50 PM

Awesome find; they don’t build them like that anymore!

I just had my Samsung 5 year-old refrigerator go out (freezer side worked; fridge didn’t).

So bought new GE refrigerator 1 week ago.

Will it last 20 years? Very doubtful.

Bought super quiet Bosch dishwasher 4 years ago so my autistic boy didn’t freak out from white noise, and now it’s getting louder and performing poorer.

Meanwhile, my grandmother has a refrigerator in the basement from 1949 that still works flawlessly.

Believe all companies now only make crap as part of the great reset (ie., if you have to buy appliances and mechanicals of one kind or another every other year, it’s hard to save any money...which is the plan).

Nothing is made to last now. This year I replaced my wonderful 1990's washer. I put it off as long as possible.

Re the bolded bit: I have never used, or wanted, an electric dishwasher. If there was one in a house we purchased we ditched it. We replaced it with manpower. It's not necessarily quieter but at least no white noise!

Author Topic: Unlimited Off Grid Hot Water (Read 2177 times)

SeanJohnson

Unlimited Off Grid Hot Water

SimpleMan

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SeanJohnson

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