Wind Turbine Design and Implementation
Project Proposal
Prepared for: Tim Hanson and Sonia Michaels
Prepared by: Jessica Rush
4/28/2010[Page Break]
[Content Control]
Significance of Problem:
As a low-income individual you have expressed your concern to me about
the ever raising power cost. It appears you have taken steps to reduce
your electrical consumption by: weatherization of your home and the use
of gas for heating and cooking. However
your bill continues to be very high. One option to offset you power
costs is the implementation of a renewable resource.
Living
here in Snoqualmie, WA you have probably noticed the abundant wind
resource, available right in your backyard. I would like to offer my
services in researching and designing a “small-Scale” wind turbine, to
help offset your power consumption. In doing research I on this subject I believe it is important to take into consideration:
- Manufactures of wind turbines (to see if it is cheaper and easier to invest in a pre-built and installed turbine)
- Building Materials
- Recommended output for power consumption
- Dimensions
- Grid interconnection
- Building Codes and City Ordinances
- Mathematics involved
Qualifications:
I
am currently attending Bellevue College in pursuit of an AA in
Networking and Computing Systems, with the intent of transferring credit
to Eastern Washington University
for a BA in Applied Technology, as well as a Future Engineering degree.
I am currently enrolled in Computer Aided Design 1 at Bellevue College as well as a Technical writing class and a group communications class.
I have some experience with CAD programs, and have designed a small scale Wind Turbine Prototype for the R.U.S.H project.
Project Methods:
In doing research I will hit key points such as:
- Manufactures of wind turbines (to see if it is cheaper and easier to invest in a pre-built and installed turbine)
- Building Materials
- Recommended output for power consumption
- Dimensions
- Grid interconnection
- Building Codes and City Ordinances
- Mathematics involved
I will be using several resources including:
- Web sites
- Otherpower.com
- www.quietrevolution.co.uk/index.htm
- EbsocHost ( professional journals)
- Interviews (NO RESPONSE)
- Puget Sound Energy
- All Star Heating and Air Conditioning (local dealer of Skystream wind turbines)
- As Well as several books
Introduction to Wind Power:
Wind Energy and Wind Power refer to the kinetic energy present in the wind into mechanical power or electricity.
Wind Turbine operation Is simple, the energy from the wind rotates two
or three propeller-like blades (in a horizontal-axis turbine) around a
rotor, the rotor is connected to a main shaft that spins a generator to
produce power.
Modern wind turbines are characterized by two categories: Horizontal-axis, and Vertical-axis. Horizontal-axis wind turbines typically have two or three blades that resemble plane propellers, rotating around a horizontal axis.
Most modern wind turbines are horizontal-axis turbines. Vertical-axis
wind turbines have blades that go from top to bottom, and resemble an
eggbeater, and rotate around a vertical axis. “The most common type-the Darrieus wind turbine, named after the French engineer Georges Darrieus who patented the design in 1991.” (Renewable Wind, Energy Information Administration 2010) Many
modern turbine manufactures claim that the vertical-axis turbines are
quieter and more efficient in the urban, city environment.
Issues with Urban Residental Wind Turbine Use:
In many urban areas there are laws and ordinances that must be followed when building or installing a wind turbine. The following issues are key components of land use law, as well as public acceptance of small wind systems, and are critical for the successful placement of a turbine:
1. Setback Distances and Height
2. Lot Size
3. Aesthetics
4. Sound
5. Property Values
6. Insurance
7. Abandonment
8. Multiple Turbines
9. Urban and Building-Integrated
Installations
10. Potential of Structural or
Electrical Failure
11. Soil Studies
(In the public interest: How and why to permit for small wind systems, American Wind Energy Association, September 2008)
Setback
distance and height requirements are commonly the turbine total extent
height, which is the tower height plus one blade. The setback distance
is the distance from the property line. Most common residential lot size
requirements for wind turbines are limited to 80 feet tall, and 0.5-1.0
acre lot. These requirements are far stricter than the Aesthetics
issue. With Wind power being an image of “green” consumers and neighbors
do not want wind turbines to “stick out like a sore thumb.”
Another
issue that is of common concern in wind turbine installation in
residential areas is Sound. Most modern wind turbine have far better
insulation as well as lower rotation speeds, fewer moving parts, no
gearboxes, and more efficient blade design than previous turbines. With
setback distances the noise is very limited.
Parts of a Wind Turbine:
[Picture]
There are several small parts and gears inside of a wind turbine. The parts include:
Anemometer: measures the wind speed and transmits wind speed data to the controller.
Blades:
Most turbines have “propeller-like” blades that are fabricated out of
fiberglass, metal or wood. Wind blowing over the blades causes the
blades to “lift” and rotate.
Brake: In
case of emergencies such as extreme high winds, a disc brake is applied
mechanically, electrically, or hydraulically to stop the rotor.
Controller: Starts the machine at wind speeds of around 8-16 miles per hour and shuts off the machine at speeds of about 55 mph.
Gear Box:
Gears connect the low-speed shaft to the high-speed shaft and increase
the rotational speeds from about 30 to 60 rotations per minute to about
1000 to 1800 rpm, the rotational speed required by most generators to
produce electricity.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-Speed shaft: Drives the generator.
Low-Speed shaft: The rotor turns the low-speed shaft at about 30-60 rotations per minute.
Nacelle: Sits atop the tower and contains the gear box, low- and high- speed shafts, generator, controller, and brake.
Pitch: Blades are turned, or pitched, out of the wind to control the rotor speed.
Rotor: The blades and the hub together are called the rotor.
Tower: Taller towers enable turbines to capture more energy and generate more electricity because wind speed increase with height.
Wind vane: measures wind direction and communicate with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes.
Yaw motor: Powers the yaw drive.
Blades: design and theory:
The blades are the most important and most difficult part of a wind turbine. The energy produced depends on the swept area more than it does on the alternator
Maximum output. (How to build a Wind Turbine, Hugh Piggott May 2003) There are several important equations to remember for the blades which include: the formula for the power in the area swept by the wind turbine rotor [P=0.5*rho*A*Vcubed) (P=power in watts (746watts=1hp, 1000watts=1kilowatt) rho=air density (about 1.225 kg/mcubed
at sea level, less higher up), A=rotor swept area, exposed to the wind
(m squared),V= wind speed in meter/sec (20mph= 9m/s, mph/2.24=m/s)]
There
are several steps in creating the blades. The blade shape is produced
through a series of cuts at stations along the length of the blade. At
each station the blade has ‘cord width’, ‘blade angle’, and
‘thicknesses. The first step is to produce a tapered shape. Any rotor designed to run at tip
speed 7 would need to have a similar shape, regardless of size. The
dimensions are simply scaled up or down to suit the chosen diameter. These measurements are for an eight foot rotor.[Picture] The second step is to produce the twisted windward face; the third step is to cut the thickness. The following tables show the width, drop ( the
drop is the measurement from the face to the trailing edge of the
blade), and thickness at each station along the length of the blade.
Pieces
|
Material
|
Length
|
Width
|
Thick
| ||
3
|
Wood, fiberglass, metal
|
1200mm
|
150mm
|
37mm
| ||
Station
|
width
| |||||
1
|
6’’
|
150mm
| ||||
2
|
4 ¾’’
|
120mm
| ||||
3
|
3 15/16’’
|
100mm
| ||||
4
|
3 1/8’’
|
80mm
| ||||
5
|
2 ¾’’
|
70mm
| ||||
6
|
2 3/8’’
|
60mm
| ||||
Station
|
Drop
| |||||
1
|
1 ½’’
|
37mm
| ||||
2
|
1’’
|
25mm
| ||||
3
|
7/16’’
|
12mm
| ||||
4
|
¼’’
|
6mm
| ||||
5
|
1/8’’
|
3mm
| ||||
6
|
1/16’’
|
2mm
| ||||
Station
|
Thickness
| |||||
1
|
1 3/8
|
36mm
| ||||
2
|
15/16
|
25mm
| ||||
3
|
½
|
13mm
| ||||
4
|
3/8
|
10mm
| ||||
5
|
5/16
|
8mm
| ||||
6
|
¼
|
7mm
|
[Picture]
Rotor Hub:
Pieces
|
Material
|
Diameter
|
Thich
|
2 disks
|
Wood, metal
|
10 inches, 250mm
|
½’’, 13mm
|
The
rotor Hub consists of two disks that are placed one on each side of the
blades. 27 equally spaced screw holes should be drilled, 9 for each
blade.
[Picture]
Alternator Theory and Design:
The alternator consists of a stator disk sandwiched between two magnet rotors. Strong magnetic flux passed between the two rotors and through the coils in the Stator. The movement of the rotors sweeps the flu across the coils, producing alternating voltages in them. (How to build a Wind Turbine, Hugh Piggott, May 2003)
A cheap and inexpensive way to find an alternator is to pick up a few
from a junk yard out of some cars. GM alternators work well for this
application.
[Picture]
Tower Construction:
There are three types of tower construction, Guyed, Lattice, stand-alone. It is common for towers to be 80 feet to 120feet height. The wind closer to the ground is more turbulent.
[Picture]
[Picture]
Grid-Interconnect:
It
is possible to connect a wind turbine to a residence that already has
grid power. Typically a special meter is installed, that lets the meter
roll back in times wind the turbine is producing more than is consumed.
Pre-Built Wind Turbine Manufactures:
There are several wind turbine manufactures. Manufactures that make all different sizes of wind turbines. Small residential size such as Skystream, to large industrial size such as GE and Vista or Siemens.
SkyStream:
Technical Specifications
Rated Capacity 2.4 kW
Rotor Diameter 12 ft (3.72 m)
Weight 170 lb (77 kg)
Swept Area 115.7 ft2 (10.87 m2)
Type Downwind rotor with stall regulation control
Direction of Rotation Clockwise looking upwind
Blades (3) Fiberglass reinforced composite
Rated Speed 50 - 330 rpm
Maximum Tip Speed 216.5 ft/s (66 m/s)
Alternator Slotless permanent magnet brushless
Yaw Control Passive
Grid Feeding 120/240 VAC Split 1 Ph, 60 Hz 120/208 VAC 3 Ph compatible, 60 Hz check with dealer for other configurations)
Battery Charging Battery Charge Controller kit available for battery charging systems Braking System electronic stall regulation with redundant relay switch control
Cut-in Wind Speed 8 mph (3.5 m/s)
Rated Wind Speed 29 mph (13 m/s)
User Monitoring Wireless 2-way interface
Survival Wind Speed 140 mph (63 m/s)
Warranty 5 year limited warranty
Skystream can be purchase from an authorized dealer in Fall City, WA. All Star Heating
P.O. Box 70
Fall City Wa. 98024
425.222.7652
425.222.7949 Fax
Recommendations:
My
recommendations are if you have the money to invest it is better to go
with a pre-built wind turbine that has been tested and guaranteed.
Building your own wind turbine is difficult, and you don’t always know
the expected outcome.
However
my recommendations on building your own wind turbine are to pay close
attention to the blade design. I recommend a 32FT diameter turbine
modeled off from the dimensions in the examples.
Work Cited:
How to Build a wind turbine by Hugh Piggot May 2003
Wind Rotor blade construction by teodoro sanchez campos ITDG
Prototype 11Kw wind turbine By Simon Brookes December 12, 2005
In the public interest How and why to permit small wind energy.American Wind Energy Assoxiates
Small wind electric system, Washington consumer guide.
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