A while back a was messing around in the shop, and ended up making this water pump that uses only heat to pump. The two check valves are the only moving parts. Here is a video of it working...
Here is a drawing of what it looks like inside...
Here is another drawing of what I believe it is doing in its cycle....
The system is primed with water a bled of any air that may get trapped in the system. It’s starts to pump within 30 seconds of applying heat to the bottom of the pipe.
I believe what’s going on is that a pocket of steam is formed at the bottom of the pipe. Being that there is no air or space for the steam to expand to, instead it pushes up on the water column and forces it through the outlet check valve, achieving its expansion that way. Once the steam no longer has the energy required to continue pushing the water column, the outlet valve closes, and the pocket of steam begins to cool, having lost a good portion of its energy. Asthe steam cools in begins to contract a form a partial vacuum in the bottom of the tube. This vacuum in turn opens the inlet check valve which supplies more water to fill the voided space in the unit. The cycle then continues.
I believe it has to be using the Rankine cycle, but when I try to draw out a rough and dirty PV diagram I kind of run into a bit of a wall and get nowhere.
Can anyone explain what’s going on here a little better to me? Perhaps what I think is going on is completely wrong and somebody else has a better idea that would help me understand more. Thanks for any replies!
Well unfortunately I have come to the conclusion that it is indeed the vertical height increase that increases the flow rate.
I switched out the 2 foot 1” pipe for a 2 foot 1/2” pipe, I also had to add a 1” to 1/2” reducer along with a 6 inch long 1” pipe to accommodate the heating element. This brought the total height of the leg to roughly 32”, which is approximately 7-8 inches longer than it was when I was using the 2 foot 1” diameter leg.
The result from this was about 2.3 liters per minute or so. Roughly 0.2 - 0.3 liters per minute more than I was getting with the 2 foot 1” diameter leg. This tells me that increasing the volume does not in fact increase the flow rate, only increasing the height of the leg.
This result is actually quite disappointing to me because I figured if the volumetric increase was the deciding factor than it wouldn’t be too difficult to build something of a practical size with a practical flow rate. For example it would be feasible to build the pumping chamber to be a 4 inch diameter that was 10 inches long or so, doesnt really take up a whole lot of space.
Unfortunately it would seem to me the only method method of increasing my flow rate with this setup is to make the pipe longer and longer. Its not very practical to have a pump that’s 20 feet tall in order to pump 2-3 gallons per minute.
i’m not quite giving up yet though. I would like to find out if the height increase is affecting the flow rate because of the pressure increase that goes hand in hand with that. If it is in fact that the boiling point is increasing, than maybe some sort of calving setup could accomplish the same results without the need for an absurdly long pipe.
Well it’s been a while since the last post/update. I’ve made a few changes that have definitely helped.
The first thing I decided to do simply for experimental purposes was to install a thread in 1500w electric heating element in the bottom pipe. No my plan is not to make this an electric system, this is just for use while I experiment. Now whenever I make a change in the geometry of the system I know that my heating source is consistent, and therefore any increase or decrease in system performance must be directly due to whatever other changes I have made.
In order to accompany the thread in heating element I had to change the lower pipe from a 1/2” diameter tube to a 1” diameter tube. The first one I tried was a 2 foot long 1” pipe. This gave me a hair over 2 liters per minute pumping rate.
This was probably 0.75 liters or so more per minute than I had pumped with any other setup. Part of me thinks it’s because the electric heater is doing a much more efficient job at heating the water in the bottom than I was doing previously with my torch. Part of me however also thinks it may have to do with the increase in volume between the check valves, changing from a 1/2” tube to a 1” tube would give me almost 4x the volume given the same length.
My next attempt I again switched the 2 foot tube for an 8 foot tube of the same diameter. The result was an increase to just a smidge over 3 liters per minute. The heating element was the same one used previously. I know I said 2 liters per minute in the video, however after the video was taken a did several more flow rate tests that all resulted at or slightly above the 3 liter per minute mark, so I’m guessing the first run may have had some air trapped in the system.
The way I measure the flow rate is set a timer for one minute, turn the outlet to pump into a seperate container, while it pumps I have to be filling the reservoir continuously otherwise it will run empty. After the minute is up I shut the outlet valve off, and from there I dump the water collected in the container into several 1 liter bottles to get my result.
I still don’t understand why increasing the tube length between the check valves increases my flow rate, my question right now is this...
“Is it the increase in vertical height that subsequently increases my flow rate? Or is it the increase in volume associated with the longer pipe that increases the flow rate?”
Perhaps it’s the actual increase in height that makes the flow rate go up, with an increase in water height comes an increase in pressure at the bottom of the pipe. Increasing the pressure also raises the boiling point, perhaps that is what is going on.
Perhaps it’s the volume increase that increases the flow rate. As you can see, with the longer pipe, there is a much longer lasting outlet stroke, more volume coming out before the intake stroke begins again.
The other thing I have noticed is that the unit actually gives 3-4 outlet strokes before the inlet valve opens and allows more water to be sucked back in. This tells me that there must be 3-4 slightly pressurized oscillations of the water column within the pipe before the low pressure area is created to open the inlet valve.
More experiments to follow, hopefully I can solve the mystery of volume vs height.
Do you mean to say
During the heat addition it is a constant volume process, then when the valve opens it is isentropic process and during heat rejection it is constant pressure?
But, Lenoir cycle is a gas power cycle. I am not sure if you could apply it to pure substance like water which is in two phase in your system.
I’m a bit curious after doing some reading. Is it possible that this pump is following the Lenoir thermal cycle? Is sure seems like it would be similar, at least with my understanding of a PV diagram.
Sorry for the late reply.
Yes, your videos links are working fine.
I loved your aim with this setup
"My initial goal with this system was to try and come up with a method of pumping water that required no electricity, no flowing water, just heat. This could have great use in remote areas or third-world countries where access to either running water or electricity is not possible. Any heat source will make this system operate, burning wood, used oil, and possibly even a solar lens setup. "
As you mentioned this setup is not the most efficient but it does the work of pumping water to higher elevations. This heat source is very intense and I believe it is not cheap. Can village people use burning wood or something like that to generate a similar kind of high heat intensity?
I think you should plot a graph between the amount of heat provided vs the max height the water reaches by doing multiple experiments if it is possible. That would give some idea if the system can be used by a lot of people with different needs.
"Another point of interest with this setup is it will still pump water if the reservoir is lower than the pumping section. This means this does produce suction, for this, I simply leave the inlet check valve down low to act as a foot valve. I’ve yet to try but I’m thinking it could be possible to make this system able to pump water out of a well."
Yes, this would be great if it works. Also, experiment with the maximum possible height between suction and delivery ends so that you would get a better idea.
I am not yet sure about what kind of thermodynamic cycle it is undergoing but it does not matter. I encourage you to do the experiments. This is real engineering.
I made a couple more videos.
the first one shows it pumping to a separate reservoir. You can see the water level going down in the first holding tank as it pumps.
The second one shows it pumping to a seperate, higher up reservoir. You can notice the pumping rate goes down substantially, but hey it still pumps!
i havent set it up yet, but I will make a setup and a video showcasing that it will also pump from a reservoir lower than the pumping section, proving that it does not need the initial alter level to gravity feed to the system.
please let me know if these videos are working for you, thanks :)
Wow a lot of questions haha but no worries I will try my best to answer them all.
I believe it is producing thermodynamic work, in the sense that it is moving the water? i Have experimented and closed off the outlet and built about 10 psi, which tells me it can add energy to the system. As for driving a turbine I think if the outlet were restricted to a small diameter nozzle that it would be able to drive a water turbine or Pelton wheel, though I have yet to try it.
Unfortunately the torch you see in the video is the best heat source at source I have so I’m currently unable to test if more heat will allow it to pump more water. I have ran the pump using my heat gun which puts out less heat, and it will still pump just not as fast, so I’m assuming the answer would be yes, the more heat added the more work will be achieved.
The check valves do operate automatically. In person you can hear them pinging as they open and close. This tells me that the pumping section has to be cycling between a higher and a lower pressure state other wise the check valves would not function.
i don’t remove the heat in the cooling stage, the flame is constantly on the bottom. I believe once the steam travels up the pipe that it radiates heat out the upper walls of the pipes. In the future I would like to experiment with a water cooled section above the heated section to see if that would help increase pumping output.
Yes if the height of the right hand pipe is increased it will still pump, the pumping rate goes down obviously as More is being demanded by the system, but it does still pump. I actually went and rigged this up just to show you in the video below!
I’m not exactly sure what you mean by putting the right hand pipe Into the left hand tank, I think all that would be doing is mimicking a simple thermosiphon, although a thermosiphon doesn’t require valves, so that would just make it an overcomplicated thermosiphon haha
i don’t have a video of it, but this system will actually move water from one tank to another, it does not need to recirculate the same water, I just have it set up that way for a simpler setup.
Also another Interesting thing about this setup is that the outlet water barely absorbs any of the heat that’s being added with the torch. The setup holds roughly 1.5 to 2 liters. I’ve had it running with the torch for a good 30-40 minutes non stop in the past, and the outlet water after all that is barely warm to the touch. I believe this is because most of the heat is being absorbed and then rejected in the bottom section where the “work” is being done.
Another point of interest with this setup is it will still pump water if the reservoir is lower than the pumping section. Which means this does produce suction, for this I simply leave the inlet check valve down low to act as a foot valve. I’ve yet to try but I’m thinking it could be possible to make this system able to pump water out of a well.
My initial goal with this system was to try and come up with a method of pumping water that required no electricity, no flowing water, just heat. This could have great use in remote areas or third world countries where access to either running water or electricity is not possible. Any heat source will make this system operate, burning wood, used oil, possibly even a solar lens setup.
It may may not be the most efficient setup, but it is very cheap. Anybody can make this pump with about 30 dollars and a trip to the hardware store.
I’m wondering, are the links to the YouTube videos I’m posting on here working? It’s a great help to see it in action.
I hope I managed to answer your questions so far :)
Hi, Welcome to the Forum.
This is something really interesting and different type of system I have come across. I have a lot of questions to ask before coming to any conclusion about your system because it is something new for me too. Let's have a discussion.
Does it produce any thermodynamic work? suppose we increase the heat added at the bottom will it produce high-pressure high temperature steam to drive a small(tiny) turbine?
Does the check valve operate automatically?
Do you remove the heater during the cooling stage?
If you increase the height of the right side pipe will the water still flow up?
I ask this because I feel this is just a boiling process and boiled water is flowing upwards because of heating. If you increase the pipe height it will not come upwards.
If that is the case then this can not be a Rankine cycle, because the Rankine cycle is a steady flow process.
What if we put the other end of the pipe inside the left tank?
What is your aim for designing this interesting system?
Sorry, If I am asking too many questions but I am just trying to understand the system. Maybe these questions will lead to something. :)