Last update 26 OCT 2023

What is an Anemometer?

Anemometers are instruments that measure wind speed. Users can employ it in different installations, like for example for the management and monitoring of wind farms, weather stations, photovoltaic plants, ski lift, highways, viaducts, high routes, airports. In most applications, users equip anemometer with anti-icing system.

TYPES OF ANEMOMETERS

Based on the operating principle they are divided into the following types:

• Vane anemometers (mechanical principle of 3 rotating ‘spoons’ around a vertical axis);
• Ultrasonic anemometers (speed of sound waves propagation influenced by air motion);
• Hot wire anemometers (measures the cooling rate of a hot wire).

Depending on the output signal, we can distinguish into the following types:

• With digital output
• With analogue output
• With pulse output

USES OF THE ANEMOMETER IN THE PHOTOVOLTAIC INDUSTRY

• In the photovoltaic industry, anemometers are installed for the following purposes:
• For uses provided by the Standard EVS-EN 61724-1 (Photovoltaic system performance – Part 1: Monitoring)
• In PV systems with a solar tracker system, user need to be bring the solar tracker system into a safe position in the presence of wind gusts exceeding a given threshold detected by the anemometer.

To assess the increase in production caused by the wind considering that:

• Wind increases the cooling of PV modules and this leads to an increase in their efficiency.
• The wind generally carries away particulates suspended in the atmosphere, which reduces the solar radiation reaching the earth’s
  surface.
• Wind generally affects the humidity of the air, which has a negative influence on the solar radiation reaching the earth’s surface.

Frequently, users add wind direction indicator or vane meter to the anemometer. This is a ‘wind vane’ that marks the direction from which the wind comes. By relating the output data with module temperature, wind speed and direction, it is possible to understand from which directions the driest, wettest or coolest winds come, etc.