Home
Project Details
Gallery
Windmill History
Archived News
Resources |
The original goal of project windmill is to create a completely independent and wireless web server using the existing Hampshire windmill. Achieving such an objective could offer insight into providing similar services to remote or undeveloped locations.
In addition, this project will provide a great deal of education to the project members and the Hampshire community. Energy concerns are beginning to rise, and this project can provide insight into an alternative and renewable energy supply.
If others are interested in participating in the existing project, or want to work on another windmill related project please contact Jared Benedict by email at: jared@wonka.hampshire.edu
To make this project possible, many intermediate steps must be taken. The windmill itself needs many repairs to return it to its original condition.
Quite a bit of research also needs to be done on the web server end. It is still unclear what type of computer will be required. Ideally, a low power laptop would be usable. This would allow the use of a standard Linux/Apache operating system/web server solution. If there is too little electricity or funds available to acquire a wireless capable laptop, then an alternative will have to be worked out. Another option is a low powered embedded solution where the entire operating system, web server, and web pages are permanently stored in a ROM chip or perhaps flash memory. This requires much less power, but I'm unsure how far along the embedded market. Getting an embedded solution that provides wireless support may be just as expenssive as a laptop solution.
Because wind in the area is erratic and low speed on average, the system will likely require a hybrid system which generates electricity from the windmill and a photovoltaic solar panel. This electricity may need to be stored in a separate battery.
The simplified schematic below illustrates how the web server would be a completely wireless and independent device. The windmill will most likely send it's generated power to a battery. A low powered web server will be connected to the battery. The web server will send it's data wirelessly via the 802.11 standard to a base station, which will probably be located in the nearest building in Enfield. The base station receives the signal and sends them to their final destination via Hampshire's network.
Early Wish List - Below is a list of items that may be needed. It's still early in the game so needs may change.
- Sun & Wind
- Windmill
- Paint
- Wood
- Alternator/Generator
- Solar Set-up
- PV Panel
- Charge Controller
- Batteries
- Inverter
- Server
- 486 Laptop with PCMCIA slot
- Wireless Ethernet PCMCIA Card
- Wireless Ethernet Base Station
Project Questions (and slowly... Answers!)
General
- Why am I doing this project?
It seemed like a neat idea. The project actually contains several areas of interest. Renewable energy, computing, wireless technology, and design all interest me and this was a way of squishing them all together.
Computer Questions
Web Server Questions
- How much power does a computer consume?
A number of experiments have been made to determine the approximate power consumption of Laptop computers. For my prototype, at least, I intend to use a laptop as they are already designed for low power consumption.
Procedure: I conducted my test by connecting the different laptops to a modified KWH meter. (Like what is outside of your house.) The laptop connects to the meter, and the meter then connects to an outlet.
How data was obtained: The meter is unique from others that I've seen. It is not obvious what one revolution of the disc indicates in terms of KWH. Because of this, I decided to use a known power consumer, a 75 Watt incandesant light bulb. It took the light bulb 170 seconds to rotate the disc once. I used some special laws of proportion to then determine the unknown watt consumption of the computer. I have yet to varify if my method is correct with someone who really knows the laws of proportion. I connected the laptop to the meter and got all the settings configured. I then simply timed how long it took the current configuration to turn the disc one rotation. I read that normal (home sized) meters are fine tuned enough to measure such small wattages so it should be accurate.
Below are descriptions of the computers I have tested so far. The Toshiba is what I plan to use for my protoype because it was what is available. (Thanks to Josiah and his brother for the donation.) Unfortunately, it only has 4 MB of RAM which may make things pretty difficult.The iBook was available for testing and I was curious. I knew that PowerPC used less power than Intel chips, but it would appear from my tests that the iBook actually uses less power than the old 486. I was surprised by this and did the test on the laptop twice. I've done some testing with a PowerMac G4 just to see how laptops compare to desktop computers.
A couple strange things happened that probably make the data slightly off.
- The meter isn't easy to read. My times could have been off by a few seconds in either direction.
- The iBook's hard drive (even though clearly instructed not to) spun down in the last minute of the test. I had to turn the screen on and run an application to get it spun back up.
I don't think those two things change the data too much. In addition, I'm not that interested in exactly how much power is consumed, I'm just trying to get an general number. There are however some odd results. If you compare test 3 to test 4, the results indicate that keeping the hard drive spun up actually reduces the power consumption. Also if you compare test 1 to test 2, it would appear that keeping processor cycling off decreases power consumption.
Next I need to do some tests where the drive and processor are actually doing something. In the below tests, there weren't any pages being accessed.
| Tested Computer Descriptions |
| Manufacturer |
Model |
Processor |
Proc. Speed |
HD |
HD Speed |
RAM |
Screen |
OS |
| Apple |
iBook |
PPC G3 |
300 Mhz |
6 GB IDE |
??? |
96 MB |
12.1" SVGA TFT color |
OS 9 |
| Toshiba |
Satellite T2115CS |
Intel 486 |
75 Mhz |
??? |
??? |
4 MB |
broken |
win 3.1 |
| Apple |
Power Mac G4 |
PPC G3 |
450 Mhz |
10 GB IDE |
7200 RPM |
128 MB |
17" Apple CRT |
OS 9 |
| Apple |
PowerBook G3 |
PPC G3 |
400 Mhz |
??? |
??? |
??? |
14.1" SVGA TFT color |
OS 9 |
| Energy Consumption |
| Test # |
Computer |
Watts |
Screen |
Hard Drive |
Proc. Cycling |
Approx. KWH/month (comp. running for 730 hours/month ave.) |
| 1 |
iBook |
7.8 |
off |
spinning |
on |
5.69 |
| 2 |
iBook |
6.59 |
off |
spinning |
off |
4.81 |
| 3 |
iBook |
13.14 |
on |
spinning |
off |
9.59 |
| 4 |
iBook |
13.42 |
on |
spun down |
off |
9.80 |
| 5 |
Satellite |
9.20 |
off |
spinning |
off |
6.72 |
| 6 |
Satellite |
9.18 |
off |
spinning |
off |
6.70 |
| 7 |
Power Mac G4 |
20.02 |
off |
spinning |
off |
14.61 |
| 8 |
Power Mac G4 |
103.66 |
on |
spinning |
off |
75.67 |
| 9 |
PowerBook G3 |
8.88 |
off |
spinning |
off |
6.48 |
- How do I decrease the amount of power required by a computer?
From what I've read, heard, and found in my tests, the screen is the biggest energy consumer in a laptop or desktop computer. Luckily, I don't need a display for a server. The next largest consumer is the hard drive. It is in theory possible to get rid of the hard drive. Having content that changes becomes an issue but there are ways around it. The next largest consumer is the processor. From the tests it appears that a PowerPC chip does indeed use a significant less amount of power than an x86. I'll work with what I got. :-)
- How much energy will the server consume per hour, day, month, year?
According to the numbers above (using the satellite tests 4/5) it needs about 6.75 KWH per month. Keep in mind this is a rough estimate and the above tests weren't actually serving any content. With actual disk access and processor tasks running (which will be tested later) energy requirements will be higher.
- Are there computers devices that do similar tasks (wireless web server)?
Wireless Questions
- What kind of antenna should I use?
- Can I make my own antenna?
- Can I use an antenna that others around campus can connect to?
- Should I use products from Cisco (Aironet), Orinico (Wavelan), other?
- What sort of range can I expect?
- How can I increase range?
- How much do trees and other obstacles reduce the singal?
Energy Questions
Wind Questions
- What repairs or modifications does the windmill need?
- How much power does the windmill produce?
From "More Other Homes and Garbage":
The Savonius, or S-rotor, rotates much slower than a modern two- or three bladed propeller and is less than half as efficient in capturing the wind's energy. It must , therefore, be geared and its cross-sectional area (to intercept the wind) must be quite large to make up for its inefficency. The Machines requrie a large surface area of material and so are heavy and hard to balance. Small do-it-yourself units can be made out of 55-gallon drums (see Hackleman's nice booklet in the Bibliography), but they deliver so little power that they hardly seem worthwhile. For example, a machine made from three 55-gallon drums stacked one on top of the other, having a cross-sectional area of about 27 square feet and an efficiency of about 20 percent of the theoretcial maximum, produces about the same amount of power as a simple high-speed prop with a diameter of less than 4 feet. Hackleman's figures indicate that one such stack will probably yield less than 10 kWh per month in 10-mph average winds. Figure 3.10, in case you hadn't noticed, includes an approximate power-output curve for such a unit. S-rotors are not particularly appropriate for the generation of electricity, although their good-torque, slow-speed characteristics make them useful for such applications as pumping water.
- What are average windspeeds in this particular area?
- How do I convert the rotational motion of the windmill into electricty?
Photovoltaics Questions
- How much power does a PV panel produce?
- What are the average sun conditions in this area?
Below are energy values compiled by Solar Pathways Corp. from horizontal data given in University of Wisconsin EES report no. 44-2 (F-Chart Data). This will soon be translated to kWh.
| Amherst, MA. Latitude: 42.2 degrees |
| angle |
Jan. |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
dec |
| BTU/SQ FT/DAY For Surfaces Facing South |
| 0 |
428 |
653 |
1106 |
1280 |
1589 |
1895 |
1902 |
1622 |
1217 |
922 |
564 |
457 |
| 20 |
560 |
800 |
1270 |
1340 |
1580 |
1830 |
1860 |
1670 |
1350 |
1140 |
760 |
650 |
| 30 |
610 |
850 |
1320 |
1330 |
1530 |
1760 |
1790 |
1640 |
1370 |
1220 |
860 |
730 |
| 40 |
650 |
880 |
1330 |
1290 |
1450 |
1650 |
1690 |
1580 |
1370 |
1260 |
882 |
790 |
| 50 |
670 |
887 |
1320 |
1230 |
1350 |
1510 |
1560 |
1490 |
1330 |
1280 |
915 |
830 |
| 60 |
680 |
880 |
1270 |
1150 |
1230 |
1360 |
1400 |
1370 |
1270 |
1270 |
926 |
850 |
| 70 |
670 |
850 |
1200 |
1040 |
1090 |
1180 |
1220 |
1230 |
1180 |
1220 |
915 |
850 |
| 90 |
610 |
740 |
984 |
790 |
780 |
810 |
840 |
891 |
930 |
1060 |
830 |
790 |
| degree days |
1283 |
1100 |
927 |
540 |
250 |
41 |
7 |
22 |
122 |
398 |
725 |
1159 |
- How big a panel do I need?
- How can I get my hands on a PV panel?
Batteries
- What type of batteries should I use?
- How many batteries do I need?
|
