1. STEMTECH 2010
Engineering Club Involvement in Residential Wind Generator Design
November 2, 2010
Bob Zickefoose
Blue Ridge Community College
Weyer’s Cave, VA

2. Blue Ridge Community College
Formed an Engineering Club in 2009
Originally 24 interested students
Approximately eight active students
Purpose was to begin alternative energy studies
Initial project involves wind energy

3. Blue Ridge Community College
Project involves design of a residential wind system
System will interface to utility power supply
System components are “off the shelf”
Completed unit will be installed locally
If successful, unit will be manufactured locally

4. Blue Ridge Community College
Currently available systems are very expensive
Tower represents a major portion of cost
For wind systems to become widespread, they must be more economical
Project goal is to be able to produce and install a wind system for ½ current cost

5. Residential Wind Generators Bergey 10 kW

6. Wind Energy Generation
To be economically feasible, a unit must cost less than $20K
This includes the cost of installation
Many wind units are not installed in proper locations
In the East, good sites are very geographically specific

7. Wind Energy Rules Power in the wind is not linear with wind speed
All average wind speeds are not the same
Better to monitor before installing a wind generator
Be mindful of units rated wind speed

8. Wind Power Equation Simplified
P = x D² x V³
P is power in the wind in kiloWatts
V is wind speed in mph
D is Rotor Diameter in ft.

9. Expected Power (Watts)

10. Wind Energy Physics
All average wind speed sites are not created equally.
You need to know the wind profile for the site (through at least one year of monitoring).
Wind profile will tell you how many hours each year the wind is blowing at a given speed.

11. Average Wind Speed Example
Suppose we have two sights A, B. We have a identical wind generators installed at both sites that have a 20 ft rotor diameter.
At site A, the wind speed is a constant 10 mph all of the time. Average wind speed is 10 mph
At site B, the wind speed is 20 mph for exactly one half of the year, and there is no wind blowing the other half of the year. Average wind speed is 10 mph.

12. Average Wind Speed Example
Using the formula (P = x D² x V³) or the table provided, we find that
At sight A, output will be 360 Watts all of the time.
At sight B, output will be 2880 Watts half of the time, and 0 Watts the other half
Site A production = 360 W x 8760 hr/yr = 3253 kWh/yr
Site B production = 2880 W x 4380 hr/yr = 12,614 kWh/yr
Conclusion: site B produces 3.9 times as much energy yet both sites have the same average wind speed.

13. Wind Speed Variation Turbulence

14. Wind Speed Variation Turbulence

15. Wind Speed Variation Turbulence
The rule of thumb is that turbulence of a height of 2h will occur from an object of height h for about 500 feet around the object.
Therefore, if you house is 25 ft high, and it is the highest object for 500 ft around it, you want to have a wind generator height of at least 50 feet to the bottom of the rotor diameter.

16. Wind Generator Sizes
Wind generators are often classified as residential (small wind) vs. commercial (large wind)
Large wind generators are often installed in clusters of many units (wind farms)
Normally residential wind generators will be rated between 1-20 kW.
Large wind generators are usually rated 75 kW to multi MW

17. Residential Wind Generators Southwest Wind power 3.7 (1.8kW)

18. Blue Ridge Community College
Students participated in tower design
Students participated in detailed unit drawings
Students participated in prototype assembly

19. SolidWorks Modeling

20. SolidWorks Modeling

21. SolidWorks Modeling

22. SolidWorks Modeling

23. Tower Assembly

24. Tower Erected

25. Unit Assembly .

26. Control System .

27. Blades and Tail Vane

28. Blue Ridge Community College
Remaining tasks include housing design
Remaining tasks include unit installation
Remaining tasks include unit testing

29. Shell Mock-Up

30. Career Studies Certificate

31. Questions?