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.

Step 1: Material Required for Prototype

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

Materials:

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
Screws
Epoxy
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
Chisel
Screw drivers
Pliers
(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. :)

Bibliography:

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

Credits:

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)

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