Woodstove heating rainwater: Thermosiphon enough to get upstairs?

I collect rain water off of my roof. I run it through a natural sand filter. I am interested in heating the water with a wood cook stove, however I want to store the heated water in a water heater that is upstairs and therefore above the rain water collection point. I know that a thermosiphon moves water upwards, but most the setups I have seen recycle the water inside of one single tank. I have also seen people say that it cannot take water above the point where water is being drawn from, While others say that there is a certain amount of rise given a certain amount of heat. I found this thread very helpful, yet discouraging because some people say a thermosiphon is not reliable. https://permies.com/t/72296/Thermosiphon-Direction-travel

I made a diagram of my setup and Idea. I have two floors, the shower is upstairs. The rain water collection point is about 3 feet under the total height of how high the water tank would need to be to reach the shower. Would the water need to be extremely hot to climb up that distance? Would a water pump be the only way to make this work?

Any thoughts would be much appreciated, especially if you have had experience with a thermosiphon water heater! Thanks.

You would ned perpetual motion for that to work.
Nobody has achieved that at the moment.
I deal with this everyday, I have a heap of questions first;
- Do you have electricity?
- is the tank in the roof a gravity feed tank?
- how do you hope the hot water will get to the shower head?
- what size pipe do you have between the wood stove and the upper tank?
- Do you believe in miracles?
I can help you if the answers are given.

I have plenty of experience with thermosiphoning systems and all work real good.
Pipe size is important, and difference in elevation between the heat source and the entry point to the hot water tank.
I use 15M lengths of 1/2 inch copper pipe around a 6 inch flue pipe, with the cold water supply from the tank bottom, entering the coil at the bottom.
At times this pipe will start boiling and puffing steam into the vented storage tank at times.
The exit point of the coil [ hot water ] is about 4 feet below the bottom of the hot water storage tank.
The tank is 3 ft tall and the hot water enters about 9 inches down from the top.
The pipe between the coil and the tank is 3/4 inch.

I also heat the same tank in summer with a flat solar collector.
It sits on the ground, is angled at about 45 degrees
The cold inlet goes to the base and the hot water exit is about 5 feet off the ground and about 7 feet below the tank base.
I use 1 inch copper pipe between the tank and the collectors.
In summer the panels are 100 degrees C.

Any pipe run must be continuously rising, allowing no air bubbles to form inside the pipe,

John C Daley wrote:You would ned perpetual motion for that to work.
Nobody has achieved that at the moment.
I deal with this everyday, I have a heap of questions first;
- Do you have electricity?
- is the tank in the roof a gravity feed tank?
- how do you hope the hot water will get to the shower head?
- what size pipe do you have between the wood stove and the upper tank?
- Do you believe in miracles?
I can help you if the answers are given.

No electric, but that could always be implemented at some point.
The tank is fed by gravity, rainwater.
The water may just come as a trickle out of the shower head, but ideally the water heater would be as tall as the shower head. Heck maybe a bathtub is the best option...
I don't have any pipe to the stove yet, I figured I would gather some info on if this is even possible before doing anything.
I do believe in miracles, but i tend to not count on miracles when it comes to moving water, heheh...

John C Daley wrote:I have plenty of experience with thermosiphoning systems and all work real good.
Pipe size is important, and difference in elevation between the heat source and the entry point to the hot water tank.
I use 15M lengths of 1/2 inch copper pipe around a 6 inch flue pipe, with the cold water supply from the tank bottom, entering the coil at the bottom.
At times this pipe will start boiling and puffing steam into the vented storage tank at times.
The exit point of the coil [ hot water ] is about 4 feet below the bottom of the hot water storage tank.
The tank is 3 ft tall and the hot water enters about 9 inches down from the top.
The pipe between the coil and the tank is 3/4 inch.

I also heat the same tank in summer with a flat solar collector.
It sits on the ground, is angled at about 45 degrees
The cold inlet goes to the base and the hot water exit is about 5 feet off the ground and about 7 feet below the tank base.
I use 1 inch copper pipe between the tank and the collectors.
In summer the panels are 100 degrees C.

Any pipe run must be continuously rising, allowing no air bubbles to form inside the pipe,

What I am talking about is running cold water from one tank, to the stove to heat the water, and then the heated water rising into another tank that is higher than the first. The real question I need answered is if there are any formulas determining heat vs rise of water on thermosiphons.

Your diagram won't work.

Think about what would happen to the water with the stove off. The water in the upper (hot) tank would simply drain down through the stove and to the rainwater storage tank, where it will overflow.

Thermosyphons don't move water uphill, they allow water to CIRCULATE in a system. Warm water entering your storage tank displaces cooler water, which returns to the stove by another pipe.

Michael has explained it clearer than I did.
Thats why I used the term perpetual motion, something that will work with no input of extra energy.
In your case, heating water will not cause it to go to a higher tank.
You need a pump for that to happen.
The details of the hot and cold pipes is the magic of thermosyphoning.

Right, since you are expecting the heat to lift the water it won't work.
If there was a closed loop with a return you might get the heat to move around.
Since the cooler return loop would be pulling down on the output,
to help pull the water up the other side.

An air compressor running very little air could be used to lift the water.
Inject it low and the air will carry water up with it.

This is an awesome idea and I love your thinking.  I have installed a similar system that has been in use for several years now.  It works great - but you have a couple of hurdles to cross first.

First - you need pressure.  Pressure to take your water input to the top of your tank (think: like a traditional water heater) this cold water is piped inside the tank depsiting the cold water near the bottom of the inside of the tank - again, like a traditional water heater does.  I use a traditional water heater as my tank.

Typical water pressure inside a home is 40-60 lbs.  This pressure you have provided will then allow you to fill your tub on the top floor.  Electricity will be needed to provide the pressure in the system you have described.  

Second - you will need a cold water return coming from the BOTTOM of your tank and into the water jacket at the stove.  Here the water is heated and then it will thermosiphon up to an intake near the TOP of your tank.  As the hot water enters the top of the tank, cold water at the bottom of the tank will circulate down to the stoves water jacket to be heated and sent back up.

Other things you should consider:

Pressure relief valves.  One near the hot water exit from the water jacket and one near the top of the tank.  THESE ARE NECESSARY!!  You have created a steam bomb.  Extreme pressure will build in this closed system.  If there is no relief and you burn enough fire without using enough of the water - It will blow up in a catastophic manner.  NO JOKE.

A second water tank.  This will help in taking up the extra hot water created and put less stress on the system.  Plus, it will be bonus to have extra hot water stored.

Once your system in in place and working - you cannot simply not use it any more.  There must always be water in the jacket at the stove or it will burn up.  Also - and most importantly - the water must always be circulating and being used or you will create the bomb that I mentioned earlier.

This link may be helpful in getting what your looking for:  http://inthewilderness.net/2017/01/27/homestead-hot-water-thermosiphon-loop/