A turbine is a machine that converts the kinetic energy of a spinning fluid into useful work or energy via a rotor system. Mechanical gearing or electromagnetic induction allows turbines to generate power in this way. There are different types of turbines but the prevalent ones are classified as horizontal and vertical-axis wind turbines. In this article, you’ll learn all about horizontal axis wind turbines their functions, and also horizontal axis wind turbine types.
What is a Horizontal Axis Wind Turbine?
The most prevalent type of wind turbine in operation today is the horizontal axis wind turbine or HAWT. HAWTs have a rotor with aerodynamic blades (i.e., airfoils) attached to it; this rotor may face either into or away from the wind. High-Altitude wind turbines typically have two or three blades that rotate at very fast rates. Coned blades on downwind rotors make it possible for the turbine to self-orient into the wind, but upwind rotors need a yaw or tail vane to help them face the right way. However, downwind rotors have been seen to wander when aligning with winds at low speeds, resulting in reduced energy output at those speeds.
HAWTs feature horizontally mounted shafts that are perpendicular to the ground. HAWTs, like VAWTs, can have either two or three blades. To date, the three-bladed HAWT has proven to be the most effective design, however, the two-bladed rotor and the rotor facing the wind models have both enjoyed some success. The nacelle’s turbine can either face upwind (at the front) or downwind (at the back). There is no need for a mechanical orientation system in downwind devices because they always point in the direction of the wind. The constant rocking from gusts of wind is the biggest drawback since it leads to more weariness. Now let’s learn about horizontal axis wind turbine types.
What are Horizontal Axis Wind Turbine Types?
Horizontal axis wind turbines have a really effective design and are pretty famous in the market. Like other wind turbines, there are also horizontal axis wind turbine types. The types are as follows-
1. Upwind Turbine
The rotor of an upwind wind turbine is installed on the top of the tower. This turbine’s primary goal is to prevent wind from casting a shadow over the tower’s back side. Because it is rigid and set back from the tower, this configuration is currently employed in most HAWTs.
2. Downwind Turbine
The rotor of a downwind turbine is positioned at the base of the structure. This particular turbine directs the wind first toward the tower and then onto the rotor blades. Due to the rotor passing through the wind shade of the tower, this wind turbine experiences some variations in wind power. Here, wind power fluctuations are brought about by the rotor’s position behind the tower’s nacelle. This should have helped you understand the horizontal axis wind turbine types.
Also Read: 2 Types of Vertical Axis Wind Turbine
What is Horizontal Axis Wind Turbine Working Principle?
After understanding horizontal axis wind turbine types, let’s also learn about the horizontal axis wind turbine working principle. Wind power is converted into torque by the rotor, which is then transmitted to a slow-moving shaft. The nacelle protects the gearbox, high-speed shaft, and generator that receive the power from the low-speed shaft. The blades are attached to the rotor and the shaft. This shaft is referred known as the low-speed shaft because the rotating assembly is turned by the wind at a leisurely rate of only about 10 to 20 rpm.
To achieve the desired output frequency of 60 Hz, the low-speed shaft is connected to the gearbox, which features a system of gears that increases the shaft’s output speed to roughly 1,800 rpm (or a speed of 1,500 rpm if the frequency is 50 Hz). Because of this, the shaft coming out of the gearbox is often referred to as the high-speed shaft. Finally, the high-velocity shaft is coupled to the generator, which transforms the rotary motion into alternating current. If this speed is utilized to directly turn the generator, the frequency of the ac output is precisely proportional to the rate at which the generator is turned.
Direct-drive wind turbines, for instance, typically use a DC generator as opposed to an AC one, and they lack a gearbox. It’s unclear whether or not an AC-to-DC converter is part of these (which can be located at the tower base). A programmable logic controller (PLC) or computer is used as the controller in industrial turbines. The anemometer’s readings are used by the controller, which then decides which way the wind turbine should face, how much energy it should gather, and whether or not the turbine should be allowed to speed up during strong winds. That is the Horizontal axis wind turbine working principle. After this, let’s explore about horizontal axis wind turbine components.
What are Horizontal Axis Wind Turbine Components?
A Horizontal axis wind turbine components include a base, tower, nacelle, generator, rotor blades, hub, shaft, gearboxes, and Anemometers.
1. Base: The tower and other components of a wind turbine weigh a significant number of tonnes; thus, they need to be securely fastened to a rock-solid base.
2. Tower: A tall structure that holds the rotor hub and nacelle in place. These may be fabricated from steel lattice, concrete, or tubular steel. One key aspect of horizontal axis wind turbine design is the tower’s height. Increasing the height of the tower allows the turbines to absorb more wind energy and produce more electricity because the wind speed increases with altitude. Increasing the height of a wind system usually results in a greater amount of power being generated and also lessens the turbulence in the wind.
3. Rotor Blades: Wind turbine blades capture the wind’s kinetic energy and convert it to mechanical energy. These razors are constructed from wood-epoxy or polyester that has been strengthened with fiber glass. Depending on the design, wind turbines may feature a single blade, a pair of blades, three blades, or more. Three-bladed HAWTs are the norm. These are attached to the hub of the rotor. In the past, people employed the idea of several blades to pump water, grind food, and do other tasks.
4. Nacelle: The nacelle is the housing for the turbine’s key components. The gearbox, high- and low-speed shafts, generator, controller, and brakes are all installed at the very top of a tower. The nacelle is equipped with an anemometer to measure wind speed and a wind vane to detect wind direction.
5. Hub: Connecting a rotor blade to the shaft of a wind turbine requires a rotor hub. Hub, bolts, blade bearings, pitch system, and internals make up the hub assembly. Steel, iron, and forged steel are used in the production of rotor hubs, and the welding process is essential. Here are some examples of rotor hubs:
6. Shafts: Shaft that transmits power to the drive wheels’ torque and stress levels in a drive shaft’s hollow or solid steel construction are extremely high. With the use of drive shafts, mechanical energy from the blade hub may be sent to the generator, allowing it to convert the rotating motion into electrical current. Typically, a wind turbine will have two shafts.
7. Gearboxes: The gearbox output shaft is coupled to the generator to transfer rotational mechanical energy. Faraday’s law of electromagnetic induction is the underlying principle of its operation. It is a device that produces electricity from mechanical energy. When it comes to wind turbines, there are a few distinct types of gearboxes: Planetary Transmission, A Helical Gearbox & Transmission with Worm Gears for a turbine.
8. Anemometers: The magnitude of the wind’s kinetic energy is largely dependent on its velocity. The cube of the wind speed is a direct proportion to the amount of power in the wind. When choosing a location, it is crucial to take into account the average wind speed in the area. An anemometer is a tool employed to determine the velocity of a wind current. Typically, you’ll find these above the nacelle.
What are Horizontal Axis Turbines Used For?
In order to maximize power output and energy efficiency, large-scale wind power plants often utilize horizontal-axis wind turbines. These wind turbines are typically seen in
- Manufacturing facilities
- Vast wind farms
- Government-sponsored buildings
With this, you have learned about what are horizontal axis turbines used for. After this, you might as well learn about horizontal axis wind turbine advantages and disadvantages.
What are Horizontal Axis Wind Turbine Advantages and Disadvantages?
Like other devices, horizontal axis wind turbine advantages and disadvantages are also quite evident. Let’s learn about them thoroughly here.
Advantages of Horizontal Axis Wind Turbine-
1. Powerful Generations
Depending on the application, horizontal axis wind turbines can be constructed with a power output anywhere from 2 MW to 8 MW. An onshore wind turbine with a capacity of 2.5–3.0 MW can generate around 6 million kWh annually, which is enough to power 1,500 typical EU homes. This is dependent on the size of the turbine and the wind speed.
2. Sufficiently Dependable
Horizontal axis wind turbines have dominated the market for many years, thus their design and development are well-advanced. Both the practicality and utility of horizontal axis wind turbines, which are already available on the market and their potential future development are investigated.
3. Exceptionally Strong Operational Winds
Horizontal axis wind turbines get the wind at higher speeds because of the height of the rotors. This means they will likely function at higher wind speeds, which is ideal for their performance. High-altitude air flow is usually consistent, making horizontal-axis wind turbines a more reliable source of renewable energy.
4. Efficiency at a Very High Level
It is impossible to convert energy without some of it being wasted. A major focus of new product development in the wind energy sector is how to increase the efficiency of energy conversion. For the time being, the most productive wind turbines are those with a horizontal axis. They’re efficient enough to convert 40–50 percent of incoming wind power into usable electricity.
Also Read: Hydrogen Energy Advantages and Disadvantages
Disadvantages of Horizontal Axis Wind Turbine-
1. Hard to move, set up, and keep in working order
Since horizontal axis wind turbines are so massive, they present significant logistical and technical obstacles during shipment and installation. Horizontal axis wind turbines have blades that can be as long as 70 meters and as heavy as 20 tonnes, making it unlikely that they could be installed on the narrow, winding roads typical of hilly regions or on regular city streets where residences, utility lines, and street lamps line the sides.
2. Inflict Harm on the Environment
There is still a lot of debate and controversy surrounding the topic of how horizontal axis wind turbines affect the surrounding environment. The roaring of the massive blades as they slice through the air, the massive shadow they cast, and the disruption they bring to surrounding fauna and ecosystems are all causes for concern.
3. Change in Marine ecosystem
Offshore wind turbines are likely to alter the marine ecosystem in ways we do not yet understand, whereas horizontal axis wind turbine blades represent a risk of collision with flying creatures. Multiple studies have found that wind turbines are not directly responsible for more than one percent of the annual deaths of birds in the United States caused by accidents with man-made objects and practices.
4. Tight Requirements for Setup
Regulations for wind turbine development and installation might be obstacles, despite the fact that governments around the world have provided incentives to embark on the renewable energy revolution. For a horizontal axis wind turbine, for instance, the required setback from an adjacent home is typically four times the turbine’s entire height. The city government needs to do a noise study before allowing a wind farm to be built there. Considering both the background noise and the noise the wind turbine will generate is essential. While there is often a good rule of thumb, the policy may still differ depending on factors including the political climate, the social climate, and the natural climate.
HAWTs are playing and will play a large part in your renewable energy-based future. It’s very necessary to understand all the things about such technologies like horizontal axis wind turbine advantages and disadvantages, horizontal axis wind turbine types, etc. They help you be ready for the future that’s about to come.