STEMTECH 2010 Engineering Club Involvement in Residential Wind Generator Design November 2, 2010 Bob Zickefoose Blue Ridge Community College Weyer’s Cave, VA zickefooseb@brcc.edu 540-453-2406

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

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

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

Residential Wind Generators Bergey 10 kW

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

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

Wind Power Equation Simplified P = 0.0009 x D² x V³ P is power in the wind in kiloWatts V is wind speed in mph D is Rotor Diameter in ft.  

Expected Power (Watts)

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.

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.

Average Wind Speed Example Using the formula (P = 0.0009 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.

Wind Speed Variation Turbulence

Wind Speed Variation Turbulence

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.

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

Residential Wind Generators Southwest Wind power 3.7 (1.8kW)

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

SolidWorks Modeling

SolidWorks Modeling

SolidWorks Modeling

SolidWorks Modeling

Tower Assembly

Tower Erected

Unit Assembly .

Control System .

Blades and Tail Vane

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

Shell Mock-Up

Career Studies Certificate

Questions?