Heat (steam?) powered water pump

After experimenting with fluidyne Stirling engines, I wondered if something similar could be made to run on steam.

After many failed attempts and a lot of head scratching this is what I came up with. There’s a 1/4” diameter one and a 1/2” diameter one.

This entire arrangement was filled with water beforehand and bled of any air, so there is absolutely no hot air in this system.

I believe the water at the bottom of the tee is heated to the point in expands to steam, which pushes on the water column above it, sending it out the outlet check valve. Once the steam no longer has the energy to continue pushing the water column, it starts to contract, which closes the outlet check valve. The contractions creates a low pressure area at the tee, which opens the inlet check valve allowing more water into the system.

Here is a drawing of what I’m thinking 2783-A9-CB-4613-4667-9460-EC1-AB029-A500 — ImgBB

I have modified the system to have the pumping unit (the TEE) to be above the water level with the inlet check valve remaining at the base of the tank (like a foot valve) and it does indeed create a suction, so the water level does not have to be above the pumping unit in order for it to work. Unfortunately I don’t have any pictures or videos of when I made this modification.

I would like to see some better flow rates with the 1/2” but unfortunately my little heat gun just doesn’t put out the heat I believe it would take to up that flow rate. My plan is to build or modify some sort of small wood burner with the copper tube inside the chamber so that the water can absorb as much heat as it can, that should increase the flow rate, although I’m sure if it gets too hot it will likely shoot steam out the outlet, but some tweaking can be done to minimize that, such as adjusting the depth of the tube inside the burn chamber.

I’d also like to experiment with putting multiple of these units in parallel to try and make a more even and steady flow rate.

I honestly couldn’t believe it when it worked, make a water pump that runs only on heat and has two moving parts, I know the fluidyne Stirling is the same but I can’t help but wonder if this setup might make for a more powerful pump? Who knows. I have closed the outlet valve and let the pressure build and have reached about 10 psi, but that is also just using my little heat gun, but the fact that it can build any pressure tells me it has some potential and is definitely more powerful that the equivalent fluidyne water pump.

If you look in the picture of the unit, right above the copper tube there are two big 1-1/4 to 1/2 reducers, I actually am trying to use the idea of a “regenerator” that the Stirling engines use, this section I have actually stuffed lightly with stainless steel wool, it should be acting as a heat store. It stores heat when the fluid flows from hot to cold and releases its heat when a fluid flows the other way, from cold to hot. My thoughts being that maybe it would help if the tube didn’t have to try and heat dead cold water every time. I can’t say for sure whether it’s helping or not though.

I definitely think this unit is similar to Thomas savery’s steam pump, although his operated with an external boiler and someone had to be there to open and close the valves. It’s probably a little closer to the pulsometer steam pump, although again this uses no external boiler and only has one pumping chamber instead of two.

Let me know what you think :slight_smile: and if you have any ideas that maybe make it work better or possibly more efficient.


Is this self feeding right now? Looks like the reservoir feeds back from the pump source. It looks like classic thermosiphoning.

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It is in this set up you see here, but I have actually moved the outlet to pump into a different reservoir to attempt to measure the flow rate. I agree it is a lot like a thermosiphon, although the classic thermosiphon effect has little if any power, most thermosiphon setups suggest the outlet be emerged in the top of the water level from what I’ve read.

Really I think it’s a thermosiphon utilizing check valve, without them you could never pump water to any kind of head. I managed to get this setup to build 10 psi (or 23 feet of head).

Also in my experimenting I have tried building it without the lower tube in the TEE, and just simply heating a horizontal section between the two check valves, and it will not work. Sure every now and again you will get a burp of hot water or steam from the outlet, but it will never open that inlet valve because it just simply will never drop the pressure to allow this to happen. So from what I’ve found the lower tube on the TEE is essential.

Also I’ve not heard of a thermosiphon that can produce suction like this can.

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If you would like Cody I could definitely set it up to pump into another container if you would like to see it on video, no problem at all. I can also redo my set up to show that it will pump with with water being below the level of the pumping unit.


I believe you, and I do think the check valves are definitely what lets it move any real quantity of water.

I would like to see more though. My only comparison to this is like a ram pump without the expansion tank or the need for yards and yards of head pipe.


Thomas Savery and Thomas Newcomen built some of the earliest steam engines. There is a lot of info out there about them. Enjoy! :smile:

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I’ve had a bit of an obsession for a while about trying to make a pump that can run using any kind of heat source, this is my first success in 2-3 years of trying. The amount of times I’ve had these fittings and valves apart and arranged in different ways hurts to think about, but I guess finally some results. I’m really keen to get it adapted to some sort of wood burner where I can test it with some real heat and not this dinky cheap heat gun.


The fact that it uses that little amount of heat is promising. In a bigger scale with a wood burner I bet it would really move water.

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The first video shows pumping into a separate tank but with the same original setup.

The second video shows pumping into a second tank with the water level in the reservoir below the level of the pumping unit, so that it has to create suction to pull water in. I know it’s not moving much, but I think that’s the best I’m gonna get with my little heat gun.

Obviously you can’t hear it in the video but in person you can actually hear the check valves opening and closing as it pumps.


I’ve read a lot about their work and how their engines/pumps operated. Very fascinating, definitely part of my inspiration. That and the pulsometer steam pump, and more indirectly the Humphrey pump. If you haven’t heard of the Humphrey pump I highly suggest looking into it, it’s an internal combustion pump and it’s one of the coolest things I’ve ever seen. They even still have one or two running pumps in australia.


Hi’ya JustinH.
You are already aware you are juggling the factors of heat-input made density changing in liquids; atmospheric pressure-weight; and heat driven phase changing of water.

Your (electric?) heat gun has been a constant stable factor.
Woodstoves are a wildly heat output variable to introduce. Think of a juggler have to use a hollow dumb-bell half filled with a sloshing moving liquid!
Wood charcoal burners a bit less variable. Less Wild. The juggle dumb-bell half filled with sand.
You must personal values decide if this is the direction you want to pursue: natural grown solid fuels. ???
This direction has the widest world wide potential for personal usages.
It so . . . start with premade wood charcoal.

Steve unruh


Hey Steve, actually I already have a pale of charcoal pellets I made last year that would probably work just great for that!

A few years ago I also made a rocket pellet stove and it seems to be quite steady in its heat output, but then you have to buy pellets which in my opinion defeats the purpose of a “free” no electricity water pump.

My main goal is going to be to record how it performs with increased heat input. Part of me just wishes I had a tiger torch for testing, that way if things go sideways I can simply turn the propane off.

It would be nice eventually to have something adapted to a small, simple wood burner. Perhaps if that is the case I will shorten the “steam tube” inside the burn chamber, so that things can go out of control.


Here it is running off my rocket stove. The flow has increased substantially. Obviously this set is is very inefficient as most of the heat will simply bypass the steam tube in the wide open chamber.

The pinging you hear is the valves opening and closing. Actually audible without the sound of that heat gun blowing.


What you have here is an ordinary drip coffee maker. They have a flash boiler, pop-pop (or putt-putt) motor type steam pump. Go to your local goodwill thrift shop, buy a drip coffee maker, and take it apart. These are electric versions of a steam water pump.


We use only coffee percolators at our house and that uses only heat to pump hot water up to the basket with no valves or steam and takes les heat to get the job done. I like hot coffee and the drippers don’t get it hot enough for me. I’m a fussy old guy!


Yep same concept, it’s making short burps of steam in the bottom where the element is, to push bursts of water up the tube into the basket. Coffee purists grumble about the fact that brewed coffee itself is getting vaporized over and over in that little chamber at the bottom. It does give coffee a different flavor, they say, but I can’t tell a whole lot.


Boiling water makes good coffee. Fresh ground and run it though a coffee press. Just made me a cup.


you are definitely right! Same principle as a coffee maker pump (I’ve heard it called a bubble pump also). A few differences though, a coffee maker uses one valve only, at the inlet, so that water (or steam) cannot backflow into the reservoir. This one uses two valves, which should make it able to pump at a higher pressure rating. The coffee maker only having one valve also makes it so all the water coming out the other end is hot and/or boiling. In this system I’ve built the water from the outlet takes quite some time to even feel warm to the touch, it’s got to circulate through quite a bit before it will absorb any meaningful amount of heat. Getting the outlet water really hot is only desirable in the coffee maker situation, where you are trying to both pump water and heat it at the same time. In just a pumping situation it’s more indicative of wasted heat if the water gets hot. Also a coffee maker must gravity feed its inlet water, this system I’ve built can actually produce suction and pull water from a lower source. I’ve yet to do more testing but will post updates when I have.


Actually Dan if you were to take an ordinary coffee maker pump and put a check valve on the outlet side like in my version, it would not work. I know this because I’ve tried it. I’ve tried eliminating the bottom of the TEE section and just heated the section in between the two valves and it will not pump water.

I assume the reason for this is because some water escapes initially but the the remaining water now forms steam. Every now and again a burp of steam will come out the outlet pipe, but even the bursts of steam are pretty few and far between. I think the problem is even as some steam escapes through the outlet and the steam volume becomes very small, by continually adding heat to it keeps expanding and gaining energy and will not allow a low pressure area to form in order to suck more water in from the reservoir.

I’ve also tried putting the bottom leg of the TEE on it’s side and even flipped it so that it faces upwards, neither orientation works. I think the main driving factor in this system is the leg of the TEE needs to be facing down with heat being continually applied at the bottom. It needs that water column weight above it to aid in the condensing stage and in so doing create the low pressure area needed to suck more water in. If I were to leave my system as it is but remove the outlet check valve so that it more closely resembled a coffee maker pump, again it would struggle to pump water. The reason being that the water in the outlet pipe would simply oscillate up and down and not create that low pressure area to open the inlet check valve. If somehow it did manage to open the valve the pumping rate would be extremely low and it definitely would not suck water in with every oscillation of the water column.

A coffee maker pump can only work if the outlet is wide open, it has to get rid of all or most of the water in the outlet in order for the weight of the water in the reservoir to be allowed through the check valve. Any kind of resistance to wide open flow and it will struggle to continually move water out of the tank.

This system I’ve built is cyclical in nature and will pump water at a fairly constant cycling rate when heat is continually applied. Everytime steam is formed in the bottom of the TEE water is moved out the outlet, everytime it condenses more water is pulled through the inlet. A coffee maker pump although similar in nature and means of pumping (heat) is not the same thing in my opinion.


I don’t know if anyone is still keeping up on this thread or will see this reply, but I did a little experimenting and managed to more than double the pumping output of this unit! Check the video out and see it.

I found that:

  1. you get the best pumping rate if you heat at the very BOTTOM of the Tee. Yes it will pump if you heat just about anywhere along the leg, but if you heat the very bottom it will pump more water per “stroke” as it were.

  2. I rearranged the valve positions as you can see in the video. The inlet valve is above the outlet valve. I found that by doing this the bursts of water out the outlet are longer and with a bigger quantity of water each time. I can also hear a lot less pinging of the valves opening and closing. I’m thinking it might have something to do with water in the TEE configuration tries to head towards the outlet valve when it is being pushed up, but this rushing the opposite direction from the inlet valve causes a small low pressure area to build which momentarily opens the inlet valve. There definitely seems to be a much more noticeable “intake stroke” and “exhaust stroke” as it were in this current configuration.

  3. the longer you make the leg of the TEE, the better the flow rate will be out the outlet. This one I have to admit confuses me. I have no idea why adding length to this section would boost the flow rate so much, but it seems to be the single biggest flow booster. Perhaps it allows more heat to be held in the system so your flame isn’t trying to heat quite as cold of water every cycle? I’m skeptical of this reasoning however since I’ve ran the pump for 30-40 minutes non stop before, recirculating the same 1.5 - 2 liters of water and after all that time the water is barely even warm to the touch. Honestly I’m not sure the exact cause. You can see in the video the mess of pipes I added to the TEE leg in an attempt to lengthen it. If anyone has any idea as to why doing this would make such a big difference let me know! I am very curious to find the reason.