Presentation on theme: "Southwest Windpower, Inc."— Presentation transcript:
1 Southwest Windpower, Inc. The basics of wind energy and recommendations to installing Small Wind Systems
2 Wind is a form of Solar Energy REFLECTED TO SPACE53,000SOLAR RADIATION178,000RERADIATED HEAT82,000PHOTOSYNTHESIS100KINETIC ENERGY350HEAT FROM EVAPORATION40,000TIDES 3GEOTHERMALHEAT 30ABSORBED120,000Wind is solar energy transformed to kinetic energyEarth absorbs 120,000 terawatts (120·1015 watts) of energy from the sun. 0.3% is transformed into wind. This is 26 times the world’s current energy use.
3 The details of windImportant information about wind energy that you really don’t need to worry about but is good to know
4 Wind energy in scientific notation K.E. = 1/2mv2K.E. of wind = 1/2pAv3tp= density of airA = swept areav = wind velocityPower = K.E. of wind/time
5 Wind speed -and- Potential Energy Energy Available in the wind follows the equation½ (air pressure) x 3.14 (pi) x (blade length)2 x (wind velocity)3Power in 1 m2 at a wind speed of 3 m/s: 0.5 x x 3.14 x 12 x 33 = 51 W Power in 1 m2 at a wind speed of 5 m/s x x 3.14 x 12 x 53 = 236 WBeware of turbines that claim great low wind speed performance – only 51 Watts are available at 3 m/s using a 1 m blade!
6 Wind speed -and- Potential Energy Energy Available in the wind follows the equation½ (air pressure) x 3.14 (pi) x (blade length)2 x (wind velocity)3Power in 1 m2 at a wind speed of 4 m/s: 0.5 x x 3.14 x 12 x 43 = 121 W Power in 1 m2 at a wind speed of 8 m/s 0.5 x x 3.14 x 12 x 83 = 968 WEvery time wind velocity doubles,available energy increases 8 times!
7 Swept Area -and- Potential Energy How does Swept Area affect Potential Energy? How does a 1 mblade compare with a 1.5 m blade?Power in 1 m2 at a wind speed of 5 m/s: 0.5 x x 3.14 x 12 x 53 = 236 W Power in 1.5 m2 at a wind speed of 5 m/s 0.5 x x 3.14 x 1.52 x 53 = 532 WSwept Area is the best way to determine TurbinePerformance at normal wind speeds (sub 18 mph avg.)[Keep this fact in mind when comparing the Whisper H40 with the Whisper H80!]
8 Betz LimitThe maximum amount of energy that may be extracted from the wind utilizing a wind turbine is 59% of Available Energy.Most commercial turbines hover in the 20-35% efficiency(extracted energy divided by available energy).How do SWWP Turbines fare at 5 m/s?Eff. Actual Betz Lmt. AvailableAIR X 31% 30 W W WH40 31% W W WH80 28% 150 W W W% 420 W W W
9 Weibull DistributionFrequency at which the wind blowsFrom Hybrid Power Design Handbook, by C.D. BarleyWIND SPEED AVERAGE IN METERS PER SECOND – M/SAll 3 curves have the same Average Wind Speed, but will varygreatly in energy available. K=2.5 shows more consistent winds.However, the more gusty site with k=1.5 contains significantly moreenergy because of the greater occurrences of 10+ m/s velocities.
15 Barriers to wind flowBarriers produce disturbed areas of airflow downwind which are called wakes. In barrier wakes, wind speed is reduced and rapid changes in wind speed and direction, called turbulence, are increased.
16 Building Obstructions Good location for wind turbineGood location for wind turbinePREVAILING WINDRegion of Highly Disturbed FlowTurbulence2HTurbulenceHTurbulence2H20HHighTurbulenceUndisturbed upstream wind speed profile5H10H15HSpeedDecrease17%6%3%TurbulenceIncrease20%5%2%Wind Power43%9%15HTurbulence10H5HAppropriate maximum values dependUpon building shape, terrain and otherNearby obstacles.2HTurbulence
17 Siting behind a row of trees The region underneath the curve has too much turbulence, and is not a good site to install a wind turbine. ThisRegion is determined by the height (H) of the tallest tree. The region with the straight, smooth lines ABOVE theCurve has air flow that is laminar, free flowing, which is IDEAL for a wind turbine.Good location for wind turbineWINDWARDLEEWARDGood location for wind turbineGood location for wind turbineTurbulentRegionHTurbulentRegionTurbulentRegionWindDirection5H10-15 H
18 Streamers and turbulence KiteSmooth Flow(Good height to install aSouthwest Windpower Turbine)Top of barrier-induced turbulencePredominant wind directionTurbulentFlowBy using a kite and adding streamers to theline you can determine the area behind treesor buildings where turbulence is present. The areawith smooth air flow will have a straight streamer asopposed to turbulent streamers that are flappingconstantly.
19 Acceleration over a ridge Crest of Windflow (also region of maximum wind acceleration)WindSpeedPossible HighTurbulenceCrest of Ridge200%120%100%50%WindSpeed
21 Valleys between mountains PrevailingwindsZone of accelerated air flowMountainsPlainsPlains(A)MountainsValleys can be areas of high wind speeds when winds are funneled and accelerated because of the topography (valleys between mountains)Zone of high wind velocitiesMountainsPlainsValley(B)MountainsPrevailing Winds
22 Siting using vegetation Brushing: Branches and twigs bend downwind.Flagging: Branches stream downwind, upwind branches are shortThrowing: A tree has trunk and branches bent downwindCarpeting: Winds are so strong it will not allow vertical growth of tree
23 Deformation Ratio I II III IV V VI 5-9 8-11 10-13 12-16 14-18 15-21 D = A/B + C/45PrevailingWindDirectionCBADeformation RatioIIIIIIIVVVIProbable Mean AnnualWind Speed Range (MPH)5-98-1110-1312-1614-1815-21Source: Data prepared by E.W. Hewson, J.E. Wade, and R.W. Baker of Oregon State University.
24 Griggs-Putnam Index MPH 7-9 9-11 11-13 13-16 15-18 16-21 22+ m/s 3-4 Prevailing WindIIIIIIIVVVIVIINo DeformityBrush and SlightFlaggingSlightFlaggingModerateFlaggingCompleteFlaggingPartialThrowingCompleteThrowingCarpetingThe degree to which conifers have been deformed by the wind can be used as a rough gauge of average annual wind speed. (Battelle, PNL)WindSpeedIndexIIIIIIIVVVIVIIMPH7-99-1111-1313-1615-1816-2122+m/s3-44-55-66-77-88-910+Km/h11-1414-1818-2121-2525-2929-3236+
25 Siting with no vegetation If your customer can fly a flag,they can run wind turbine!
26 In a nutshell – it is just common sense Know your wind speed averageWind mapsLocal weather or television stationLocal airportSite tower 30’ (9 meters) above any surrounding object within a 300 foot radiusKnow the elevation to estimate energy loss