providing the highest quality in wind energy instrument calibration.

SERVICES

We at Otech Engineering, Inc. are committed to meeting the needs of the wind energy industry and its time-and-cost-conscious customers.

Our state of the art, open-circuit, suction-type wind tunnel test facility provides calibration services for wind measuring instruments, delivering the highest levels of quality control, testing and reporting procedures at a competitive cost.

Wind Tunnel

The Otech wind tunnel facility calibrates one anemometer at a time in an enclosed test section of size 0.61 m x 0.61 m x 1.22 m (2' x 2' x 4').

The wind is driven by a 15 hp fan motor capable of generating speeds up to 36 m/s in the test section. Current test speed protocols range from 4 to 26 m/s.

Wind tunnel speed is determined using four equally positioned Pitot-static tubes. Environmental conditions (i.e., ambient pressure, temperature, and humidity) are also simultaneously measured.

Flow quality in the test section is also uniformly maintained to within +/- 0.1% with turbulence levels less than 0.1%.

All measurements are acquired using a National Instruments LabVIEW data acquisition system, which allows for easy transition to any test protocol.

For each calibration, a final report is provided along with wind speed uncertainties in accordance with NIST TN 1297 and IEC 61400-12-1 guidelines.

Compliance Standards

Otech maintains compliance to the traceability and reporting procedures specified under ISO/IEC 17025. Until accreditation is met, Otech declares that all instruments used for velocity measurements in the wind tunnel are traceable to NIST and that such instruments are installed according to manufacturer's specifications. If requested, traceability and conformity documents can be provided.

In addition, Otech performs anemometer calibration procedures (transfer function testing) and measurement uncertainty analysis according to the following guidelines:

ASTM D 5096-02, Standard Test Method for Determining the Performance of a Cup Anemometer or Propeller Anemometer

ASTM D 6011-96, Standard Test Method for Determining the Performance of a Sonic Anemometer/Thermometer

ECN-C-05-66, Uncertainties in Cup Anemometer Calibrations: Type A and Type B Uncertainties

IEC 61400-12-1, Power Performance Measurements of Electricity Producing Wind Turbines

ISO 17713-1, Meteorology - Wind Measurements - Part 1: Wind Tunnel Test Methods for Rotating Anemometer Performance

NIST TN 1297, Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results