WindMill Assembled

WindMill was assembled and with a minor wind got it rotation at No load. Still needs wiring and improvement in other things..

Let me show you a scary picture;)..My 4.5 year son standing near the windmill ..The windmill is not that fast but my camera can't capture the running object as stand still..

Back to The WindMill

I am currently playing with three projects:
   1- WindMill   (90% completed)
   2- Solar Concentrator  (95% completed)
   3- Dual Axes Solar Tracking System (99% completed)

WindMill project needs more attention for long time. Yesterday did some more work. The Generator was assembled on the structure. today made Steel plate for holding the blades. As the blades are made out of 10mm thick PVC pipe. To attach the blade on the plate i need to add a wooden fixture between the blade and steel plate. This wooden structure should have flat at bottom and profiled at top. The Flat bottom shall rest on the steel plate whereas the blade will fixed on profile of wooden fixture.
I scanned a portion of PVC blade to get the profile vector of it and then made the 3D model for CNC machining.

You can see a piece of PVC blade perfectly fit on the CNC machined fixture.

I hope in few days i will start wiring of the windmill.

Can Concentrated Solar Power generate MW of electricity?

Concentrated solar power (also called concentrating solar power, concentrated solar thermal, and CSP) systems use mirrors or lenses to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Electrical power is produced when the concentrated light is converted to heat, which drives a heat engine (usually a steam turbine) connected to an electrical power generator.

CSP is being widely commercialized and the CSP market has seen about 740 MW of generating capacity added between 2007 and the end of 2010. More than half of this (about 478 MW) was installed during 2010, bringing the global total to 1095 MW. Spain added 400 MW in 2010, taking the global lead with a total of 632 MW, while the US ended the year with 509 MW after adding 78 MW, including two fossil–CSP hybrid plants.

CSP growth is expected to continue at a fast pace. As of April 2011, another 946 MW of capacity was under construction in Spain with total new capacity of 1,789 MW expected to be in operation by the end of 2013. A further 1.5 GW of parabolic-trough and power-tower plants were under construction in the US, and contracts signed for at least another 6.2 GW. Interest is also notable in North Africa and the Middle East, as well as India and China. The global market has been dominated by parabolic-trough plants, which account for 90 percent of CSP plants.

Concentrating technologies exist in four common forms, namely parabolic trough, dish Stirling, concentrating linear Fresnel reflector, and solar power tower.

I am thinking of making small scale steam turbine from the plans:
http://www.greensteamengine.com/products.htm 

My approach to Parabolic Solar Concentrator

Recently purchased a small satellite dish for making a parabolic solar concentrator. The idea was to take a feel of the heat it will generate.

I pasted 1 inch square mirror pieces with resin on the dish. It took more than 03 hours to mount hundreds of them. In the morning i just brought it into sun and viola in 03 seconds it started smoldering wood and other plastic things. It was a good start:

Some more experiment and temperature monitoring yet to be done. I shall check the maximum temperature attain on the focal point and will expand this topic here.

The initial results are very promising so far.  I am surprised the abundant heat generation with this method. I am seriously thinking of using this heat.

I have an idea to make a bigger custom parabolic structure and mount flat mirrors on it.Installation of two axes sun-tracking and mounting a small boiler at the focal point. Use the generated steam to run small turbine to generate electricity.

Oh really.. should i have to design the steam turbine and fabricate it? How much steam it shall require to generate atleast 500watts of electricity from the generator? How big the parabolic concentrator to give me continuous steam for running turbine?

Can i avoid generating electricity by using steam turbine? any other way to make electricity ?

May be we able to make some simple system to harness this heat..  Thermodynamics is all about the temperature difference ;)
 

Dual Axes SunTracker with Advanced Options

Finally i came up with the new efficient algorithm for the dual axes sun tracking system. The tracker is menu based , parameters can be set with 6-keys keypad with following functionalities:

1- Single Axis or Dual Axis control settings

2- 12VDC / 24V DC motor (windshield car motors etc) or Linear Actuator (Peak Current 10Amp)

3- PWM based motor controller. The PWM value is selectable from Menu.(0~100% duty cycle)

4- Return East Options (a- On Limit Switch stoppage based or -b- Time based)

5- User Selectable Tracking Delay

6- Load Sequencing management

7- Dark return Time setting

8- Twilight Time settings (after the twilight Dark return Time started)

9- RJ45 connectors for sensors

10- Sensors sensitivity settings

11- Highly efficient tracking Algorithm

12-Drive Off sun position setting

13-Easy menu driven parameters settings

14- Saving Parameters values in EEPROM

15-Compact and easy to install

16-Northern/Southern Hemisphere Compatible

LCD, Keypad and sensor:

I am still adding much more features as it is micro-controller driven..

Modular type:

1- Main Controller (Price Range 30~45 US dollar)

2- PWM DC Motor Controller (10 ~15 US dollar)

3- Sun Tracking sensors (single axis or dual axis) (5~10 US dollar)

4- 20x4 backlight LCD with control circuit ( 12~15 US dollar)

5- six Key keypad (2 US dollar)

6- Optional controller to sensor wiring

Mistakes... I think i am learning new things...

One more addition of foolish blunder in my life below i posted a CAD drawing snap of the magnetic plate and stator... Something is very wrong in it.. 12 magnets and 12 coils... Its not possible

After casting and painting the magnetic plates and making 9 coils when i assembled the coils around the magnets i feel that i have wide gaps between the coils... Then i consulted the drawing i made earlier, their were 12 coils.. what a nonsense... no way... This should be 9 coils...not more not less...

So i have to destroy the magnetic plates for salvaging the magnets... Now i am going to make new magnetic plates with small diameters...This is a good thing..but why this happen, its still needs to be figured out.. this regularly happens in my life and reminds me i am a human and not a genius.

Back to the drawing board, corrected the entire things... I am posting the improved coil winder picture that made my life easy. It took 40minutes to make 9 coils, each 110turn with 1.5mm dia laminated wire (SWG17)

You can see i am arranging the coil for resin casting. I am using electrical glass tape for high temperature. i know some time the temperature of the coil will be high during high winds and not want to make another blunder by using the simple tape.


In the drawing you can see rectangle magnets, its 3 phase , so if you see closely the purple coils are at the center of magnets. It means they are providing the full voltage at this condition. the other coils are in the middle of high voltage range when the purple coils are at high peak voltage.

PS:
i have made the coils first, then measured the dimensions and reverse engineer the magnetic plates. i think this is the easy way to go.


"Sometimes when you innovate, you make mistakes. It is best to admit them quickly, and get on with improving your other innovations. "

Test Coil, Country flag and Turbine blades

I made a test coil winder earlier and today i made one coil with 37 turns. I didn't add any varnish coat but the coil is difficult to remove from the fixture ... I shall make another simple jig tomorrow that will ease up removing the coil without destroying it.

"Roman" at cnczone posted a helping post in my thread about Coil winding , following are his words for everybody who need to wind the coils:

"About your coil winding jig, I have done many coils and even worked in an electrical motor shop that had a few commercial coil winders.

Suggestion 1; Put the jig on the end of a portable electric drill (with a speed control) and then it can wind automatically. A lathe is also good if it has a low speed.

Suggestion 2; You can paint the coil with varnish or nail polish every layer as you wind it, which will then be a reliable solid coil when done. However this will stick badly to your coil former. If you made the coil former from polyethelene (like food chopping board) the glue will not stick and you can make solid coils then pop them off the former. You might need a small taper on the middle round part, to slide out of the coil.

The magnetic forces on the windings will be high, so somehow they need to be set in resin or varnish. Otherwise if there is any air in the coil the windings will flex and rub because of the magnetic field and soon wear through the insulation and fail.

If putting a dry winding in resin we would put in a vacuum chamber to make sure the resin goes through the coil and no air is present. It is easier to varnish the coil as you wind it, every layer, so I would go for the polyethelene former and do that. Varnish type is not that important, quick dry nail polish is an acrylic and will be strong and bond well later when you set the hard coil into the former with resin."

I hand rotated the magnetic plates and got 1.5Volts (don't know about the RPM) with single test coil. Tomorrow i shall borrow a stroboscope and will plot a graph between RPM and Voltages. following is the formula to get estimated cut in voltages.

Required Cut in Voltages= VAC(of test coil at cut-in speed) x No. of coils/phase x1.732(multiplication factor for 3 phase)x1.414 (DC conversion factor) - 1.4V (diode drop)

The cut-in speed i shall keep around 150~200RPM. You can see pictures of furling flapper that is turned into flag of my country.

Three PVC blades 6feet each worked out by my brother one year back . The blades are big you can see pen kept on the center blade for comparison.

Wind Mill Charge Controller arrived

At last i received the wind mill charge controller. It took about 15 days to reach at my door step from Hong Kong port :).. It seems very solid and i have also recieved the software CD to monitor various parameters of the wind turbine.
I also completed the furling tail flapper.

Birthday of My son

Coil Winder Jig completed

I have completed the coil winding jig. Meanwhile, i purchased the copper laminated wires SWG 17 number for making coil. The price of laminated wire per Kg is 11US dollar. I purchased 5.5Kg of laminated wire.

Fiber Glass Resin Casting of magnetic Plates

Yesterday, after two failed attempts of fiberglass resin casting of magnetic plates i at last succeeded.

Alternator mount Frame and Furling completed

Today i have completed the Alternator mount frame and furling design. I cut the 55 degree triangular jig which make the whole assembling process very easy and timely.

Beware of Advertisements- Chinese Wind Turbines

Recently I spent some time going over ads for micro turbines, and there's lots of interesting claims out there. So before anybody parts with their hard earned cash some wind math is in order.

A case in point is an ad for a micro turbine:
"We build these wind turbines to provide 1200watts of power. They are suitable for charging 12/24/48 volt battery systems....in winds over 4-5mph (6.4-8kph or 1.7-2.2ms)...Brand new 24” (.61m) blades."

Wow, 1.2kW from a 48" (1.22m) diameter blade. Unless you live in a wind tunnel you'll never see that kind of an output.

The most energy you can extract is 59.3% of the total kinetic energy contained in the wind. Most small scale turbines operate much lower then that, while industrial turbines approach it, but still can't get there.

According to the Bertz co-efficient you would need a sustained wind of 27mph (43kph or 11.9ms) to get 1200w from a 48" (1.2m) or 4ft blade (Wind turbine diameter=8ft). To come to this number we need to use some wind math;
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First we need the swept area of the rotor;
Area = π x (blade diameter x blade diameter) / 4
Using the above ad - 3.1416 x (1.22 x 1.22) / 4 = 3.1416 x 1.4884 / 4 = 1.17m2
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Power in watts = .5 x air density x swept area x wind velocity³
Where - air density (@ sea level) = 1.23kg/m3
            - swept area in m2
            - velocity in meters per second
So.......... .5 x 1.23 x 1.17 x 5.5ms3 (5.5ms is my areas average wind speed)
               .5 x 1.23 x 1.17 x 166.37 = 117.91 watts
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Now lets try doubling the blade area;
.5 x 1.23 x 2.34 x 5.5m/s3 = .5 x 1.23 x 2.34 x 166.37 =  239.42 watts
*Doubling the blade diameter roughly doubles the power output.
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Now lets use the original swept area and double the wind speed;
.5 x 1.23 x 1.17 x 11m/s3 = .5 x 1.23 x 1.17 x 1331 =  957.72 watts
*Doubling the wind speed roughly increases 8x the original power output. Yet we're still not at the 1200watts from the original ad.
--------------------------------------------------------------------------------------------------------------------------
Using 43kph wind speeds;
.5 x 1.23 x 1.17 x 11.95m/s3 = .5 x 1.23 x 1.17 x 1706.49 = 1227.9 watts
Wind speeds like this happen very rarely in most areas of the world.


Below is a spreadsheet showing output at different wind speeds using the above 3meter (9ft) diameter wind mill.

More CNC and Metal work

Today i machined the template for marking the position of Stator Holes on the structural frame. This template shall also be used for Resin casting. Moreover, the metallic structure for mounting the wheel hub and magnetic plate is also fabricated. Some snap shots of today's work.

 The picture shows an Antique drill machine in local workshop where the structure being fabricated.