Presentazione di PowerPoint

1
NUMERICAL AND EXPERIMENTAL METHODS FOR WIND
SHEAR INVESTIGATIONS AND POWER CURVE
SITE-SPECIFIC ADJUSTMENT Francesco Castellani,
Andrea Vignaroli and Emanuele Piccioni
University of Perugia Department of Industrial
Engineering castellani_at_unipg.it
Technical Research Centre of Finland andrea.vignar
oli_at_vtt.fi
2
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• OUTLINE
• INTRODUCTION
• THE WIND SHEAR
• The normal wind profile
• Numerical investigations
• Experimental investigations
• TURBINES POWER CURVE ADJUSTMENT
• CONCLUSIONS

• OUTLINE
• INTRODUCTION
• THE WIND SHEAR
• The normal wind profile
• Numerical investigations
• Experimental investigations
• TURBINES POWER CURVE ADJUSTMENT

3
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• WIND SHEAR AND WIND RESOURCES
• THE NORMAL WIND PROFILE (IEC 61400)

• ASSESSMENT STUDIES WILL FOCUS ON HIGHER AND WIDER
  REGIONS OF THE ATMOSPHERIC BOUNDARY LAYER

4
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• THE BOUNDARY LAYER CONDITIONS ARE GENERALLY
  AFFECTED BY
• ROUGHNESS (NEAR THE TERRAIN)
• OROGRAPHY
• THERMAL CONDITIONS (SLIGHTLY FAR FROM THE
  TERRAIN)

5
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• NUMERICAL STUDY THROUGH CFD
• SUITED FOR THE ASSESSMENT OF THE INFLUENCE OF
  ROUGHNESS AND OROGRAPHY (usually operating on
  neutral conditions)
• RECENTLY WAS INTRODUCED THE POSSIBILITY TO MODEL
  DIFFERENT ATMOSPHERIC CONDITIONS (operating as
  DIAGNOSTIC MODEL)

STUDY OF A TEST CASE SITE IN SOUTHERN ITALY USING
WINDSIM N.B. Non neutral conditions were
initialized through the MONIN-OBUKHOV LENGTH
6
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
CLASSIFICATION OF THE ATMOPSPHERE by means of
modeling
Mesoscale simulations of the area (WRF by
La.M.M.A.)
A Extremely unstable conditions D Neutral conditions
B Moderately unstable conditions E Slightly stable conditions
C Slightly unstable conditions F Moderately stable conditions
Stability time history according to Pasquill
Monin Obukhov Length
CFD simulations
7
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
CALCULATED WIND PROFILES FROM THE PREVAILING WIND
DIRECTIONS
8
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
CALCULATED WIND PROFILES FROM THE PREVAILING WIND
DIRECTIONS
9
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
10
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
EXPERIMENTAL INVESTIGATION USING A SODAR
A THREE MONTHS MEASUREMENT CAMPAING WAS PERFORMED
USING A MINI-SODAR MODEL VT-1 FROM ATMOSPHERIC
RESEARCH TECHNOLOGY
THE AIM WAS TO VALIDATE NUMERICAL PROFILES WITHIN
THE SWEPT AREA OF MULTI-MEGAWATT TURBINE WITH AN
HUB HEIGHT OF 90 m AND A ROTOR OF 100 m
11
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
CLASSIFICATION OF THE ATMOSPHERE using
experimental data
315º lt DIR lt 345º
WRF
Sodar data
Data Filtering
Shear f (stability)
Thomas

THOMAS METHOD
standard deviation of vertical-wind
speed horizontal-wind speed
12
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• THE ATMOSPHERIC STABILITY
• DEFINED USING METEREOLOGICAL DATA FROM THE
  MESO-SCALE PROGNOSTIC MODEL WRF
• VALIDATED APPLING THE METHOD PROPOSED BY THOMAS
  TO THE SODAR DATA

Measured normalized vertical profile ranked
according to the stability conditions
Occurrences of stability conditions during the
measurement campaign
13
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
HOW WIND SHEAR AFFECTS THE TURBINES
PERFORMANCE?
The Betz hypothesis uniform intensity
distribution on the rotor
The Profile approach uneven intensity
distribution on the rotor surface
The power curve The power output is affected only
by the wind speed at hub height
a correction of the Cp is necessary
14
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
HOW WIND SHEAR AFFECTS THE TURBINES
PERFORMANCE?
15
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
HOW WIND SHEAR AFFECTS THE TURBINES PERFORMANCE?
16
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
HOW WIND SHEAR AFFECTS THE TURBINES PERFORMANCE?
17
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
MODELING THE WIND PROFILE IS POSSIBLE
18
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS
IMPROVING THE ESTIMATION OF ENERGY PRODUCTION IS
STILL POSSIBLE
Roughness ,Terrain and Thermal conditions
CFD SIMULATIONS
WIND FLOW CALCULATIONS
PRODUCTION ESTIMATION
TURBINE OPERATIONAL CONDITIONS
POWER CURVE CORRECTION
Climatology Atmospheric conditions
19
Francesco Castellani? University of Perugia
Dept. of Industrial Engineering
THE TURBINES POWER CURVE
INTRODUCTION
THE WIND SHEAR
CONCLUSIONS

• CONCLUSIONS
• Usually thermal effects are neglected in wind
  energy assessment studies but in some situations
  this is not the case
• SODAR measurement and CFD simulations can be very
  useful to improve the reliability of energy
  assessment analysis even in wind sites where
  non-neutral conditions can have a relevant role.
• Two methods for the classification of the
  atmospheric stability has been compared and
  successfully applied in a wind energy study.
• In the future the application of remote sensing
  (SODAR and LIDAR).can represent a useful approach
  for characterizing the lowest part of the
  atmosphere to improve wind resource assessment
  studies.