What are the Differences between Mechanical and Ultrasonic Wind Sensors?

Did you know that Ultrasonic wind sensors can detect wind gusts as low as 1 sec in duration? The world is shifting towards more modern ultrasonic wind sensors, making mechanical wind sensors obsolete. Ultrasonic wind sensors are reliable, low-maintenance, and more accurate than mechanical wind sensors. Even in extreme weather conditions, ultrasonic wind sensors provide reliable results with excellent repeatability.

These wind sensors mainly consist of semiconductor electronics with no moving parts. As there is no physical movement, they do not require frequent maintenance. It contains a set of transducers that produce sound waves that pass through the air and detect them at the other end. The time these sound waves take to travel from one end to another changes due to the speed and direction of the wind.

In addition to their exceptional accuracy, ultrasonic speed sensors can obtain online data at ultra-low wind speeds without minimum thresholds and small angle measurements without limits. Are you prepared to let go of mechanical wind sensors? Continue reading for an in-depth comparison.

Principle Difference of Wind Sensors in a Glimpse

The design of the working mechanism, detection technique, and mechanical and ultrasonic wind sensor differ drastically. Here are the critical points between mechanical and ultrasonic wind sensors to consider:

Mechanical Speed Sensor

➢ Operation: Relies on physical components interacting with the wind to measure speed and direction

➢ Cost: Generally more affordable

➢ Limitations: It requires a minimum wind speed to generate data and is susceptible to wear and tear, which can affect accuracy over time

➢ Maintenance: High maintenance and frequent calibration

➢ Application: Low precision requirements such as agriculture

Ultrasonic Speed Sensor

➢ Operation: Utilizes sound waves to determine wind speed and direction without physical components

➢ Performance: Offers high accuracy, repeatability, and the ability to measure at extremely low wind speeds

➢ Cost: Typically higher initial investment compared to mechanical sensors

➢ Maintenance: Zero repair or lubrication requirement with infrequent calibration

➢ Application: High precision such as research and industrial use

Mechanical Wind Sensor

Mechanical wind sensors utilize the old technique of moving and rotating parts to measure wind speed and direction. There can be a generator inside the sensor assembly that generates current proportional to windspeed, or electronics can perform a similar function.

Since they contain moving parts, they require frequent maintenance. Mechanical wind sensors are used in agriculture and metrological sites because, in these applications, we don’t need high accuracy. The cost of installation of mechanical wind sensors makes them relatively affordable.

Types of Mechanical Wind Sensors

1. Propeller Anemometers

It consists of a propellor that measures wind speed and a vane that measures wind direction. It is similar to the shape of a windmill but smaller in size. It generates output proportionally to the speed of propeller rotation. Wind causes the propeller to change direction, so speed and direction are measured simultaneously.
 

2. Pressure Plate Anemometers

These wind sensors work on converting pressure into wind speed through mechanical deflection. It's ideal for scientific applications where accuracy is critical. However, they lack repeatability and require frequent calibration.

3. Cup Anemometers

The wind sensor is a rotating three- or four-wind cup structure. The rotation of the wind cup converts into an electrical signal, which measures the wind speed. It detects changes in wind direction by using a mechanical wind vane. It detects the direction of the wind with its rotation.

4. Vane Anemometers

This type has propellors or turbines that rotate to measure the wind speed, and the vane ensures it aligns with the wind direction. The vane also provides the direction of the wind.

5. Hot-Wire Anemometers

It consists of a wire heated by an electric current. When air flows, the wire cools, and the cooling rate is measured and converted to wind speed.
 

Output of Mechanical Wind Sensor

The mechanical sensor's output for wind speed is voltage or current, proportional to the wind speed. For direction, we use a potentiometer. The direction of the wind is equal to the output of the potentiometer.

Ultrasonic Wind Sensor

Ultrasonic wind sensors have no mechanical parts. They consist of a receiver and an emitter of ultrasonic sound waves that measure wind speed and direction. They are famous for their high accuracy and reliability.

Types of Ultrasonic Wind Sensor

1. 2D Ultrasonic Wind Sensors

This type of anemometer measures wind speed in two dimensions using two transducers to send and receive signals. The wind speed and direction influence the time taken by the pulses; this technique calculates speed and direction.

2. 3D Ultrasonic Wind

Similar to 2D, this type utilizes the same principle to detect speed and direction of speed, but it is more complex, having multiple transducers. It provides detailed information regarding wind speed in vertical and horizontal directions and information about turbulences.

3. Compact Ultrasonic Wind Sensors

These are very small and compact compared to the normal ones, but they use essential speed and direction measurement principles from ultrasonic wind speed measurement devices. They also have the advantage of being weighted and energy-efficient. 

4. Heated Ultrasonic Wind Sensors

Heated elements in these sensors maintain a specific temperature for accurate measurement and to protect it from snow that can cause inaccurate readings due to obstruction in sound pulses. In cold climates

5. High-Precision Ultrasonic Wind Sensors

These wind sensors measure the speed and direction with high accuracy and resolution. They have high-quality transducers and advanced algorithms for calculation; the working principles of these sensors are similar to those discussed above in 2D or 3D wind sensors.

6. Solar-Powered Ultrasonic Wind Sensors

Solar-powered ultrasonic wind sensors are the best option if you need a wind sensor installed at a remote location without electricity. These sensors come with solar panels and batteries. The working principle is again the same because they are the same ultrasonic wind sensors, just supplied with solar power.

Working Mechanism of Ultrasonic Wind Sensor

Ultrasonic wind sensors utilize the principle of ultrasonic time difference to calculate and measure the speed of the wind and its direction. The speed of ultrasonic sound waves increases if the direction of the wind is the same as that of sound waves, and the speed decreases if the direction of the wind is opposite to the sound waves.

These sensors represent a valuable use of ultrasonic detection technology in gaseous mediums. They have four probes that send and receive ultrasonic sound waves traveling through the air to measure the speed and direction of the wind. These sensors also calculate the wind temperature.

Output of Ultrasonic Wind Sensor

Ultrasonic wind sensor has a digital output for both speed and direction, whether in serial data where data is in meters per second or production can be in the form of pulses. The speed of wind is proportional to the frequency of pulses. The sensor calculates the speed with an accuracy of ±1-2%—similarly, direction with an accuracy of ±2°.

Some wind sensors also provide data related to the temperature. The system uses this data to remove the wind speed and direction errors. Since ultrasonic wind sensors are a new technology, you can have the output of real-time monitoring, data logging, and graphical display.

Differences in Tabular Form

As you can see, ultrasonic wind sensors are much better than mechanical wind sensors in every aspect.

Reasons For Ultrasonic Wind Sensor Superiority over Mechanical

Several reasons make ultrasonic wind sensors superior to mechanical wind sensors. The next step is to build the most important ones, as discussed below.

➔ Accuracy and Precision

There are no moving parts in the ultrasonic wind sensor, which eliminates friction, making it more accurate ±0.1 to ±0.5 meters per second (m/s) for speed and ±1 to ±2 degrees for measuring direction even in low wind conditions. This accurate repetitive measurement is critical in industrial applications. They are also susceptible to any change in wind speed and direction. Most of these sensors compensate for environmental factors and provide accurate real-time data.

➔ Durability and Reliability

The durability of ultrasonic wind sensors is excellent as there are no moving parts, so there will be no mechanical failure. Even in harmful environments, they are durable over a more extended period than the mechanical type of wind sensor by choosing a material that is UV, rust, and resistant to extreme temperatures. To increase their durability, they can withstand shocks and vibration. These sensors are provided with redundant transducers so that if one fails, another will perform the job, increasing reliability. The built-in diagnostic tools come with sensors for analysis. These sensors come with digital signal processing, which makes them capable of canceling noise and improving overall reliability.

➔ Safety

Mercury is a poisonous element. Using alloys and lightweight materials to construct ultrasonic wind sensors ensures no mercury use, making them environmentally friendly and imposing no hazard to health. The sensor is also lightweight, with fewer chances of falling from height during high wind conditions.

➔ Data Quality

The data provided by ultrasonic wind sensors is high-quality, with high accuracy (0.1 to ±0.5 m/s for speed and ±1 to ±2 degrees for direction), precision, digital signal processing, fast response time, and noise reduction features, making it the best choice for industrial use.

➔ Affordability

Using ultrasonic wind sensors is cost-effective, but their initial cost is much higher than mechanical wind sensors. However, certain advantages make these sensors more affordable and last longer.

● Less maintenance requirement, making low downtime

● Durability

● Energy efficient

● Can integrate with older data acquisition systems

With all these benefits, ultrasonic wind sensors are cost-effective even after having a higher initial cost because the total cost of ownership is low.

Applications of Ultrasonic Wind Sensors

● Industrial Stacks

Using Ultrasonic Wind Sensors in industrial stacks allows for monitoring pollutant dispersal and managing the airflow from the stack to protect the environment. The real-time data provided by the Ultrasonic Wind Sensors is crucial in controlling the airflow from the stack to the environment.

● Weather Detection and Prediction

Data from ultrasonic sensors are provided to numerical weather prediction (NWP) models to forecast future weather. Since the data is very accurate, the forecast is also exact. They are also helpful in predicting severe weather conditions. Data obtained from ultrasonic wind sensors is also beneficial in Long-Term Data Collection for climate studies and environmental impact.

● Renewable Energy

Ultrasonic wind sensors can play an essential role in the wind energy sector. They are ideal for site evaluation, long-term planning, and monitoring and are integral to wind farms. Online data available from wind sensors is essential in optimizing the performance of wind turbines.

● Transportation

Ultrasonic wind sensors are utilized in almost all forms of transportation for safety, especially in aviation and maritime. They are also used in the design of roads and bridges where wind speed is very high. For railways, they are used to check if the weather could affect the operation and scheduling of trains.

● Research

Ultrasonic wind sensors have applications in various fields of research. Some are listed below.

● Meteorology and Climate studies

● Atmospheric Research

● Wind Resource Assessment

● Pollutant Dispersion Studies

● Ecological Research

● Maritime Research

Maintenance of Ultrasonic Sensors

❖ Easy Cleaning

Before starting cleaning, check the sensor physically. If it requires cleaning, use a soft cloth. Never use an abrasive cloth. Since there is no mechanical part, it’s easy to clean it.

❖ Software Updates

Since it's an electronic device, it always operates with the latest firmware for better performance and security. Before every calibration activity, regular software updates using the manufacturer's prescribed procedure are essential.

❖ Calibration

Ultrasonic sensors are pre-calibrated by the manufacturer at the factory. After that, the user must perform the scheduled calibration as the manufacturer prescribes. Testing the sensor's performance against standardized equipment is vital for accuracy. The calibration of standardized equipment should done by the maintenance team as per international standards and procedures.

❖ Power Supply Check

Ensuring healthy power is very important for the operation of wind sensors. The periodic power supply checking through visual means and its current and voltage measurement should always be within the limits. Power fluctuations can damage the sensor. Therefore, surge arrestors before the power supply are important. Faulty components should always be replaced with genuine parts. Proper checks of the power supply can prolong the life of the wind sensor.

Final Words

Considering that ultrasonic wind sensors have enormous advantages over their mechanical counterpart, they are the ideal choice for most users. The ultrasonic sensing mechanism is superior in repeatability, accuracy, low maintenance, and calibration. A clean power input is enough to make ultrasonic wind sensors perform at their peak potential. The days of lubricating bearings and applying grease are long gone. Only cleaning or calibration is enough to keep the equipment running healthy.

Consider ultrasonic wind sensors for applications where you need precision. For low sensitivity and non-critical applications mechanical wind sensors still provide feasible options. Modern mechanical wind sensors have design improvement to reduce their drawbacks. The choice is yours!