Vapour TorQ




About: I'm a student, studying Engineering. I'm learning electronics, robotics, wood working and science in general. I enjoy hacking and disassembling as much as designing...I love Travelling, Hiking and cycling.

Our Objective:
To convert low grade thermal energy into mechanical torque using phase change.

The Scientific Principle that does the 'magic':
Our prototype is principally a heat engine which uses the principle of vaporisation and condensation. The prototype exhibits a simple technique of converting low grade thermal energy into mechanical torque. The model uses a fluid with a low boiling point to change the centre of gravity of a balanced network of pipes and reservoirs to make it rotate using a heat reservoir. Each of the set of two reservoirs contains a liquid {Dichloromethane (CH2cl2)} which makes it the working fluid. The working fluid has a boiling point of 39.6 degrees Celsius. As the reservoir gets inundated in the hot water bath, the liquid present in the reservoir vaporises. The vapours formed force the liquid to be transferred to the other reservoir. As a result this changes the centre of gravity causing the wheel to rotate. The mechanical torque thus produced can be used to power a variety of machines.

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Step 1: Material Required for Prototype

Here is list of all the materials we used to create our prototype: Vapour TorQ, Version 2.0


Copper tubes/Brass tubes 1/4" diameter, 50" length: $30
Copper tube : 3/4" diameter, 3" length: $8
Wood (general hard wood)
Stainless steel reservoir: $20
Ball Bearing (depends on the diameter of copper tubes): $4
Dichloromethane (DCM) 1 litre: $45
Aquarium heater (for testing purposes): $6
Arduino Mega 2560: $35
LM-35 temperature sensor: $0.6

Tools Used:

Drill press
Circular saw
Disc Sander
Heat gun
Screw drivers
(General tools you would use for wood working and metal work)

[Though pictures of Vapour TorQ, Version 1.0 are included, the materials required are with reference to Version 2.0]

Step 2: Virtually Creating the Prototype on Autodesk Inventor

The first step before getting your hands dirty is to create a virtual copy of your project on a software like Autodesk Inventor. Here are some images of our design. [Version 2.0]

Step 3: Building What We Call the 'VT- Hub' and Brass Pipe Soldering

First off, we had to assemble a jig to fit the copper center of the hub in place for drilling.
Then the drilling in pre-marked areas.

The next was to assemble to Brass pipes at an angle. We used a process called solder sweating.
Simultaneously, we spray painted the other half of the hub (a PVC pipe) matte black.

We also rigged up our own logo. Etched on the Copper and the Spray Painted for the 'Hub'

Then the final polishing, shining and buffing.

Step 4: Fitting and Fixing + Teflon Tape and Thread Sealing

The fitting was done with help of Teflon tapes to seal the tube tight enough so there is no leakage of any sort.

Step 5: Fluid Filling and Heating to Vapourize It to Drive Our the Air Before Finally Sealling It

Before attempting to fill the tubes with the liquid (in this case, DCM), it is of utmost importance that air be driven out of the tubes. This can be achieved by heating the pipes and then, very carefully, pouring it in one end while the other has been sealed.
A Leak Test and a Heat Test also needed to be performed after sealing it to ensure the fluid is pumping well.

Step 6: Building the Wooden Frame for the Reservoir

The first step was to establish the size of our reservoir with respect to the size of tubes/cylinders where the DCM would be.
Then, we built the wooden frame for the stainless steel reservoir tank.

After that, Lacquer for a goof finish plus so that the wood is not affected by the water in the reservoir.

Step 7: Microcontrollers and Sensors

[Note: This step is optional]
Here's the fun part...
We got hold of an LM-35, a temperature sensor (Image 4) and sealed it in a copper shell. The sensor's reading was sent to the micro-controller. The one we used is the Arduino Mega 2560 (Image 5). The data was then fed to a display (Image 2).
(Quite obviously, we first worked out the code to be fed to the Arduino)

All of this was done first on a breadboard so that corrections to the circuit could be made.
A PCB was then fabricated with the connections all debugged.

Step 8: Large Scale Prototype

The next step after this concept model would involve the production of a large scale prototype in order to acquire numerical data that allows us to increase efficiency and identify areas of improvement in both cost as well as functional parameters. This can also be used as an alternate source of energy for domestic purposes. One of its main advantages is that this idea can still be used and work efficiently where low grade thermal or heat energy is available. Examples are heat from chimneys, smoke chambers, exothermic reactions (such as combustion), absorption of light or energetic particles, friction, dissipation and resistance. Since the heat source that supplies thermal energy to the engine can thus be powered by virtually any kind of energy, our prototype has a wide range of applicability. Proposed usage scenarios include cheap solar thermal water heater powered agricultural water pumps, flour mills, band-saws, threshers, oil presses and in some cases, electric generators.

Well, there are over 1661 natural hot water springs in the United States where a large scale model of our 'Vapor TorQ' can be set up.

Countries that are renowned for their hot springs include China, Costa Rica, Iceland, Iran, New Zealand, Peru, United States, Taiwan, Chile and Japan, but there are hot springs in many other places as well, all around the globe.

We can also consider the waste produced by large factories, (temperature over 100 degree Fahrenheit of the waste), where this kind of a setup may be implemented and the energy extracted from.

This project is economically very friendly and there is no toxic waste produced.

Also, instead of using Dichloromethane (the chemical we used), we could also use organic chemicals with lower boiling points and thereby increasing the productivity.

The fact to be kept in mind is, no external power is needed to power this little creation of ours. So long as the geyser is active, our Vapour TorQ will work flawlessly with very less maintenance concerns and cost after implementation.
It will do precisely what we want it to do... Harness Energy. :)


The First Minto Wheel we saw was in an article in the Popular Science Magazine. The guy was Wally Minto

The wide wheel with the horizontal angled cylinders implemented in Version 2.0 was our Mentor, Mr. Naren's idea.

The problem with Version 1.0: the test tube design was that it required a very deep pool


The project was the brainchild of our Mentor Mr. Naren. He gave us the ideas and directed us through the whole procedure., improving on Wally Minto's original idea.

The Design and Technology Laboratory was where we did all the work, thanks to the facilities we have access to there.

Special Mentions to Ayush Nautiyal, Stephen, Aakash Deep, Raj Manandhar, Prakhar Pratap Singh, Manan Aggarwal Shivam Gupta and Dheeraj, our lab assistant.

Please view the video up on YouTube (link shared)

Like, Share, Comment and Support.

MAKE ENERGY: A US-Mexico Innovation Challenge

Fourth Prize in the
MAKE ENERGY: A US-Mexico Innovation Challenge

Burn It! Contest

Participated in the
Burn It! Contest



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    19 Discussions

    AMbros Custom

    2 years ago

    great idea.. check mine instructables too...


    I see great possibility in the concept. my suggestions:

    1) instead of using bearings, I suggest you can create a floating tube as a bearing around the shaft, that would reduce the friction tremendously

    2) the hub of the device can be the heat sink itself, filled with the evaporating fluid, and ultimately reaching the extended reservoirs at the preiphery, that way you would not be pitting the mass of the evporating medium against itself in torquing the device

    3) The arms can rise then bend 90 degrees that will preven any counter torque by residual liquid as vapour flows to the condensor surfaces.

    Notice in the image I have added a pulley to tap the shaft energy..

    Please let me know if that makes any difference.

    2 replies


    The floating bearing is a great idea, but if the torque is to be used for some work, it will need an output shaft that is fixed in place and attached to a gearbox or a belt drive speed multiplier. A floating tube system like the one in your drawing would probably lack the rigidity required but it is a great concept for a test. The individual reservoirs need to be heated in sequence as the vapor pressure in the lower(heated) reservoir pumps the fluid into the reservoir diametrically opposite to it, changing the center of mass, causing the wheel to rotate. We will test your ideas and revert to you as soon as possible. Thanks for the share and your interest.


    4 years ago on Introduction - Updated video with voice over and captions.

    We did not run extensive analysis on the model but straightaway, Friction ( in the Hub) , Pumping losses due to fluid viscosity and thermal cycling where the liquid in the upper( cold) reservoir does not cool properly, causing the system to reach a pressure equilibrium are major areas of efficiency drop. Di-Chloro-Methane has low viscosity and probably does not cause significant losses. We have used Sealed Ball Bearings on the output shaft to reduce frictional losses. We used Brass and copper to allow fast heating and cooling of the fluid to push the rotational speed as high as possible.

    Version 3.0 under development tries to use a separate fluid for vaporization and for pumping, segregating the two liquids using separate tanks and a diaphragm to transfer the forces. The whole concept of this machine is waste heat recovery from natural and industrial processes and whatever we extract in terms of mechanical power is a nett gain.

    Thank you for your interest. - Naren


    4 years ago on Introduction

    Great Work!!! When I was 25, I am now 64, I remembered when the article about the "Minto Power Wheel" was first published in Popular Science Magazine. I was very amazed with the very elegant simplicity and functionality of the project. I am further impressed with the implementation of the angled variation of the cylinders in ver 2.0 designed by Mr. Naren for improved heat and fluid transfer.


    4 years ago on Step 8

    I think a sterling engine would be a better solution.


    4 years ago on Introduction


    With a little modification it could work on solar energy!


    4 years ago on Introduction

    Wow, I've never actually seen a Minto Wheel running - kudos!

    What sort of torque or power output could you achieve? What sort of temperature differential did you need to make it self-starting?

    2 replies

    Reply 4 years ago on Introduction

    Difference in temperature can be as low as 5 degree Celsius, as long as the fluid can boil in the lower tube and condense in the upper tube for rotation. Also different types of fluids will have different boiling point. A 0.5 meter diameter Minto wheel gives an output of around 2.6 watt-seconds per revolution (.5 watts).

    Torque= weight of fluid x radius of the wheel.


    4 years ago on Step 8

    I remember seen something similar made by an inventor in Florida years ago, it was called The Minto Wheel. It was large and it could be used to pump water etc. the thing about it was that it had very slow RPMs.

    1 reply

    The primary idea is derived from the very first Minto Wheel by Wally Minto as mentioned in the Bibliography up top.
    A few ideas were then modified to achieve the very functionality that we could!