Use a polar drive. Sure the sun varies by +-23 degrees between summer and winter, but 1-cos(23 degrees) is only 8% loss at its worst. If you want maximum annual power, favour the sunny months instead. If you want the highest minimum power, favour the cloudy months. Either way you don't need an alt-azimuth drive unless that 8% is a big enough problem.
Even the biggest of those "four centuries" old windmills produce only
20kW. Good if you want to pump some water up a few metres, but hardly enough to run a modern society.
Has any wooden windmill been in operation for 400 years?
Long term means, to me, that a windmill will make rated power for its specified lifetime, with reasonable maintanance. Reasonable maintanance doesn't include replacing a burned-to-slag hub assembly or a tower crashed on the ground. Offshore hardware, like stuff on rigs, is notoriously difficult to keep reliable and maintain.
Look at page 11!
Hi,
1) I am sill confused about how to direct the motor to face the Sun. Let's say the Sun's Elevation Angle is 20 and Azimuth is 282.What angle the motor should move to a) single axis ( Assuming the motor and solar panel is on the flat ground)?
What angles two motors should move to b) dual axes ( Assuming the motor and solar panel is on the flat ground)?
Same questions as mentioned above but Assuming the motor and solar panel is on the slope)? How can I take account of the slope into my calculations?
2) I also need to send the information like bad motor or about some malfunction with the circuit wirelessly about two miles away from where the motor is located. Can anyone suggest any technology?erica
On Sat, 24 Oct 2015 19:16:02 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:
Laser link.
or
Microwave link.
or
wifi range extender link with directional antennas mounted.
The third is the easiest. and likely the cheapest.
an 8 mile job was $1400, but cheaper ones are there.
You follow the sun like a sun-flower; so, a little less than 180 degrees range, tilted at 20 degree.
You change the tilting angle ranging around 45 degrees,
You have to work out the exact angle yourself, basic geometric additions.
Use military bands, assuming your are far away from any government installations. With directional antennas, two miles is not a problem, if your are in the middle of nowhere.
Yep, y'er right: For example, at my location, the day goes from 60 to 300 degrees azimuth in June, and goes from 120 to 240 degrees azimuth in December.
One could solve the problem by tilting the entire assembly, creating an equatorial mount. However, for this contraption, it's easier to adjust the speed of the clock escapement making an hour longer during the summer and shorter during the winter. I guess that's why the builder used a 555 timer for driving the clock escapement. However, I don't recall seeing a timing adjustment pot, so this is conjecture on my part. I'll dig for the photos tomorrow, which might help.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Hi,
I was hoping to get the actual angle and tilt of the motor when Sun's Elevation Angle is 20 and Azimuth is 282. I do not know how to calculate it.
How about using GPS to send the error signals to the receiver 2 miles away? Does GPS allow user defined data to be sent?
Erica
On Sat, 24 Oct 2015 22:28:11 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:
GPS has text uplink, but IIRC it is for emergency use.
A polar mount would require tilting the panel azimuth swivel mechanism up at an angle equal to 90-Lat degrees. That certainly would work, but would also require that the weight of the solar panels be carefully balanced on the swivel mechanism to prevent any increased friction from requiring an enlarged drive motor or drive mechanism. That's roughly the way some sun tracking mirrors (heliostats) work. Note the mountings:
Optical tracker design with some interesting comments on the mounting and mechanics near the bottom of the page: "Many of my customers build their own drives. The most successful have very high gear ratios and use "Rotary Motion". I recommend the total gear ratio be something like 100,000 to 1 300,000 / 1 is even better. I like to see the system take at least 10 minutes to go from limit switch to limit switch. 1/2 hour is even better. 1/2 hour is still 24 times faster than the sun moves." Yep... slowing down the actuator speed will probably prevent it from tracking car headlights, reflections, the moon, etc. Using a C-band dish linear actuator directly: End to end travel would be: 450mm / 5.7mm/sec = 80 seconds which is 7.5 times faster than the above recommended 10 minutes. An
8:1 gear reduction would be the proper way to fix this, but it's much easier to just run the motor with 12.5% duty cycle, and get the same effect. Other pages including some other trackers: (So much for me getting anything useful done tonite).-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Even with only azimuth drive, why bother when the sun actually rises and sets, let it move from 60 to 300 degrees in 16 hours all year round. In the winter, part of that period, the sun is below the horizon, but so what ? No electricity is produced anyway. The only bad thing is the unnecessary wear of the gear during morning and evening in the winter. The error depends on the latitude how the azimuth angle is projected to the equatorial plane. The projection error is zero at the poles.
Adjusting the elevation 2-4 times a year should give pretty results.
Can you elaborate on that more? I need the wireless link for emergency situations. How much text I can send? What is IIRC?
All I need is to send some error codes like
error 1 : motor is not working.
erica
A common guideline is "If it moves, it breaks". I designed marine radios, where the general guideline was modified to "If it moves, it will soon get stuck". Offshore (marine) environments are difficult, especially with minimal maintenance.
During the early 1980's, my father was persuaded to invest in one of the first generation of windmills in Altamont Pass: In effect, he owned one of the early windmills. The original windmills were essentially a tax deduction scheme, where the primary benefit was depreciation on the original cost, with little consideration for whether it produced electricity, or not. Under those circumstances, maintenance was not a priority.
One fine day, I drove to the site to visit my fathers investment and noticed that many turbines were not turning in the wind. Somewhat later, I returned and found that even fewer were turning. When the tax laws were tweaked to provide an incentive to actually produce electricity, maintenance improved.
I don't recall exactly how long it took between installation and initial failure (MTBF?), but offhand, I would guess about 3 years. Hopefully, that has improved with today's larger wind turbines.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
It's still much too big. I don't have enough information (or talent) to properly size the motor required to move the solar panels around. However, good clue as to the sizes required can be found by looking at what commercial vendors are using. Notice the physical size of the azimuth motor and the thin wire leads in the photo. Both are quite small in size, and probably similar to the motors used in linear actuators. With a proper high gear ratio, a motor borrowed from a cordless electric drill would probably suffice. I couldn't find the exact motor type, but here's an article by someone who had a similar tracker motor fail and was looking for a replacement:
24VDC, 4" long, 2" dia. The techy stuff seems to have disappeared from the Wattsun web pile, so I can't power requirements.Incidentally, the data sheet claims +/-2 degree tracking accuracy;
I'll spare you my rant on why you don't want to use automobile or motorcycle lead-acid batteries for stationary power.
Let's pretend that you use a 12v 30A motor drive that only runs for "a few seconds per hour" and grind the numbers. To obtain +/-2 degree accuracy, I'll assume that it move in approximately 4 degree steps. The sun moves at the rate of: 360 degrees per 24 hours = 15 deg/hr = 0.25 deg/min so this device will need to cycle once every: 4 deg / 0.25 deg/min = 16 minutes Runtime will depend on the gear ratios. If I size the gears to run at
10 times the speed of the sun or 2.5 deg/min, it will need to run: 4 degrees / 2.5 deg/min = 1.6 minutes or 1.6 minutes every 16 minutes which is a duty cycle of: 1.6 / 16 = 10% Worst case is a cloudy summer day, where it has to move 14 hrs/day: 14 hrs * 0.1 * 12v * 30A = 500 watt-hrs/day I need to double that because the return stroke at the end of the day uses about the same amount of power, or 1 kw-hr/dayNow, we get into battery sizing guesswork and conjecture. Adjust the numbers to match your situation. In order to not kill the battery, I would not want to drain it below about 75% capacity. However, it might not get charged if there are several cloudy days in a row. I'll give it 7 days before the sun comes out which means: 7 * 1 kw-hr/day = 7 kw-hr/week The battery capacity (assuming no losses) is: 7000 watt-hr/week / 0.25 = 28000 watt-hr For a 12v battery, that would be: 28000 watt-hr / 12v = 2300 Amp-hr That's a mighty big big big battery. Even if you only wanted it to run for 1 day (333 amp-hr), it would still be a rather larger battery. Offhand, I would guess(tm) at least 3ea 12v 120A-hr size 27 gel cells to power this thing for one day.
Note that you can drastically improve the situation by speeding up the traverse by making the tracker move faster by reducing the gear ratio. Instead of moving 10 times the speed of the sun, let's lurch forward at 100 times the speed of the sun. That divides everything by 10 resulting in only needing a 12v 33 amp-hr battery to make it through one day. However, the might cause problems with following headlights, reflections, etc. You could also discharge the battery more deeply, but I wouldn't recommend that. Find a smaller motor please.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
I Was talikng about what I have seen, NOT what you were describing, were you expecting me to look closer at something which I have not seen?
you said nothing.
-- \_(?)_
On Sat, 24 Oct 2015 23:08:13 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:
Emergencies as in a stranded person with no means of contacting help, far away from civilization.
Not an emergency.
A "power outage potential" at "whatever facility this will be powering" is also not an emergency.
There are GPS receivers which have an expensive feature option to send an emergency rescue text of the position of the person in need.
I do not think it is for any kind of casual feeds and the only folks receiving the texts are emergency responders, so you cant send a text from one GPS device to another or say an email.
You really would need to place a computing device with network capability at the solar station and a long range wifi link to your base location. The laser suggestion is more expensive.
They used to do this stuff with microwave links. And you likely could use a private transmitter channel and band, but that would be even more expensive.
On 25 Oct 2015 07:26:40 GMT, Jasen Betts Gave us:
Show me a link to an example of a chain type garage door opener where the chain moves.
Otherwise, it is decidedly YOU whom has said not a goddamned thing.
A mobile phone SMS messages are often used for this kind of short alarm messages. There are boxes with ASCII RS-232 input which sends the message to a preprogrammed phone number.
If the system needs to be independent of public network and only 3 km range, a handheld VHF transmitter (5 W) using AX.25 would ne sufficient. The APRSS would be sufficient, but you need an amateur radio license.
Oh look.... No rain in a few months == NO POWER (hydrolectrics)
Combining those three renewable sources and the variation is evened out a bit. Long sunny periods, lots of PV but little hydrolectrics and vice versa.
Additional means to reduce the power production is to build strong continental wide electric transport networks, but of cause there are going to be right of way (RoW) issues, unless buried (DC) cables are used. Look at weather satellite images to see how the clouds move and reduce electric output at different areas during the day. A cyclone indicates where the wind is blowing and so on. Thus satellite images give an idea where electricity can be produced during different areas using PV or wind sources.
IMHO, the worst thing for increasing the use of renewable sources is the far too big subsidies. The attempt seems to be that by subsidies methods that works in one place would work in very different areas.
To select which methods to be used in each geographical area should be based on parameters for that particular area. Such parameters are:
Selecting the best combination for each area would make it possible to use far more renewable energy without subsidies.
I was expencting you to answer my question.
I'm not sure what "chain type" means to you, but this one has a moving chain.
and there's plenty of others like it.
-- \_(?)_
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