A Significant Leap Forward
Wind power engineering has tended to be a fairly conservative area of industry. No one expects any significant new design ideas that radically improve the feasibility and performance characteristics of horizontal axis wind turbines (HAWTs). Most current changes in the design and construction of rotor blades are brought about by new technologies and materials with higher strength characteristics. This ensures higher reliability and extends their service life. Such things as the amount of energy that can be extracted from the wind flow as it moves through a defined swept area have remained more or less unchanged for many years. However, the Latvian company SIA Latekols has found a way to substantially improve wind turbine performance.
By Grigory Fedotov, SIA Latekols, Latvia
The LEK design is a vertical axis wind turbine (VAWT), which has a rotor provided with either two or three arms arranged at equal angles around the vertical axis. At the end of each arm is an array in which are mounted four vertical, straight, aerodynamically shaped blades (see Figure 1). These four blades are fixed diagonally (or ‘en echelon’) within the array so that they are always at an angle to the direction of rotation. Up to three of these arrays can be mounted on each arm.
LEK and Test Results
The SIA Latekols company began building life-size prototypes for field trials as soon as the first patent was granted in 2002. Different construction solutions were designed and tested in order to optimise not only the design of the turbine’s rotor as a whole but also the individual stress retaining nodes. Simultaneously, SIA Latekols continued research work. Models of the rotor were tested in a wind tunnel. In particular, models were tested for a number of different aerodynamic rotor profiles and a range of attack angles in order to identify the best values for key parameters of the turbine rotor.
The SIA Latekols company has now produced a rotor for a 20kW LEK turbine (Figure 1), a successful outcome of some difficult but very productive research and development work.
The turbine has been installed in Latvia, is connected to the grid, and has been working in test mode. In the process of testing, SIA Latekols confirmed that the performance matched the calculations and lived up to all expectations. The LEK turbine can reliably produce a 30% increase in power over a rival HAWT with the same swept area.
LEK-20kW Settings and Features
Key technical information for the LEK-20kW is listed below and the components are shown diagrammatically in Figure 2:
The rate of rotation at the nominal wind speed is 40 RPM (low-speed turbine). The LEK turbine will begin to rotate at a wind speed of 2m/s. The operating temperature range is from –40 to + 50 degrees Celsius (the temperature range is determined by the characteristics of the generator).
LEK and How it Differs from HAWT
The many advantages of the LEK design over a conventional HAWT are worth listing:
Unlike a HAWT, each LEK wing is fixed at both ends. This gives substantial strength to the blades and helps to make significant savings on the use of expensive materials. It is also worth noting that the delivery and set-up of LEK heavy duty blades can be done in 12m sections, which reduces shipping costs. The LEK turbine is also easier to install and maintain.
The Economics of the LEK design
All the test results show that the LEK turbine is highly efficient. This new design is guaranteed to produce and supply 30% more power than a conventional HAWT in the same location. For example, at a wind speed of 7.23m/s the LEK-20 supplies the grid with 6.7kW.
Figure 3 shows the frequency (%) of wind speeds (in m/s) at the LEK-20 site over the course of a year. On the basis of this data, the amount of energy the LEK-20 produces in one year has been calculated and in Figure 4 this is compared to a HAWT with the same swept area.
According to the AWEA, the cost of producing 1kWh of electricity using small wind turbines is between US$ 0.10 and 0.15, while the cost of 1kWh of electricity produced by the LEK-20 is no more than US$ 0.07.
Conclusion
Developed by SIA Latekols, the LEK turbine offers excellent prospects for the world wind industry as a whole. Large-scale use of this radically new design for extracting power from the wind will make a significant change to wind energy production. The LEK design offers an excellent opportunity to make this industry more attractive in terms of the rate of return on investments.
In conclusion, it should be noted that SIA Latekols has also completed the entire project design and design documentation for the production of LEK turbines of 5, 30, 250, 600 and 850kW capacities.
Biography of the Author
Grigori Fedotov has a PhD in organisation of management from the Moscow Academy of Management, Russia. He has wide and relevant experience in engineering and management. For the past ten years he has worked at SIA Latekols, which specializes in studies, development and research on new means of receiving energy from a wind current. At the company, Grigori Fedotov is in charge of all works on development and testing prototypes of the new LEK rotor turbine.{/access}
Wind power engineering has tended to be a fairly conservative area of industry. No one expects any significant new design ideas that radically improve the feasibility and performance characteristics of horizontal axis wind turbines (HAWTs). Most current changes in the design and construction of rotor blades are brought about by new technologies and materials with higher strength characteristics. This ensures higher reliability and extends their service life. Such things as the amount of energy that can be extracted from the wind flow as it moves through a defined swept area have remained more or less unchanged for many years. However, the Latvian company SIA Latekols has found a way to substantially improve wind turbine performance. By Grigory Fedotov, SIA Latekols, Latvia
{access view=!registered}Only logged in users can view the full text of the article.{/access}{access view=registered}SIA Latekols has produced a new rotor design which will greatly improve performance. The company has launched a rotor turbine of improved efficiency, which is unlike any other in the world. The design has the working title LEK. The LEK design, in both theory and practice, significantly increases the amount of energy extracted from the wind by using a new design concept. All rights to this invention belong to SIA Latekols and are protected by national patents in 60 countries.
Patent and ClaimsThe LEK design is a vertical axis wind turbine (VAWT), which has a rotor provided with either two or three arms arranged at equal angles around the vertical axis. At the end of each arm is an array in which are mounted four vertical, straight, aerodynamically shaped blades (see Figure 1). These four blades are fixed diagonally (or ‘en echelon’) within the array so that they are always at an angle to the direction of rotation. Up to three of these arrays can be mounted on each arm.
LEK and Test Results
The SIA Latekols company began building life-size prototypes for field trials as soon as the first patent was granted in 2002. Different construction solutions were designed and tested in order to optimise not only the design of the turbine’s rotor as a whole but also the individual stress retaining nodes. Simultaneously, SIA Latekols continued research work. Models of the rotor were tested in a wind tunnel. In particular, models were tested for a number of different aerodynamic rotor profiles and a range of attack angles in order to identify the best values for key parameters of the turbine rotor.
The SIA Latekols company has now produced a rotor for a 20kW LEK turbine (Figure 1), a successful outcome of some difficult but very productive research and development work.
The turbine has been installed in Latvia, is connected to the grid, and has been working in test mode. In the process of testing, SIA Latekols confirmed that the performance matched the calculations and lived up to all expectations. The LEK turbine can reliably produce a 30% increase in power over a rival HAWT with the same swept area.
LEK-20kW Settings and Features
Key technical information for the LEK-20kW is listed below and the components are shown diagrammatically in Figure 2:
- Very small dimensions
- Tower height – 12m
- Rotor diameter – 7.5m
- Blades – 7.5m
- Swept area – 56m2
- Electrical systems – manufactured by ABB
- Rated power – 20kW
- Rated wind speed – 11m/s
- Maximum power – 30,000W (at 13m/s)
- Working wind speed – 3 to 25m/s
The rate of rotation at the nominal wind speed is 40 RPM (low-speed turbine). The LEK turbine will begin to rotate at a wind speed of 2m/s. The operating temperature range is from –40 to + 50 degrees Celsius (the temperature range is determined by the characteristics of the generator).
LEK and How it Differs from HAWT
The many advantages of the LEK design over a conventional HAWT are worth listing:
- The LEK turbine does not need a mechanism to point it into the wind.
- The rotor design allows rotation to start regardless of the initial position of the wings or the wind direction.
- There is no need for a booster mechanism or a spin rotor system; the aerodynamics of the rotor allow the LEK turbine to dispense with the need for them. Sustainable rotor rotation begins when wind speeds reach 2m/s.
Unlike a HAWT, each LEK wing is fixed at both ends. This gives substantial strength to the blades and helps to make significant savings on the use of expensive materials. It is also worth noting that the delivery and set-up of LEK heavy duty blades can be done in 12m sections, which reduces shipping costs. The LEK turbine is also easier to install and maintain.
The Economics of the LEK design
All the test results show that the LEK turbine is highly efficient. This new design is guaranteed to produce and supply 30% more power than a conventional HAWT in the same location. For example, at a wind speed of 7.23m/s the LEK-20 supplies the grid with 6.7kW.
Figure 3 shows the frequency (%) of wind speeds (in m/s) at the LEK-20 site over the course of a year. On the basis of this data, the amount of energy the LEK-20 produces in one year has been calculated and in Figure 4 this is compared to a HAWT with the same swept area.
According to the AWEA, the cost of producing 1kWh of electricity using small wind turbines is between US$ 0.10 and 0.15, while the cost of 1kWh of electricity produced by the LEK-20 is no more than US$ 0.07.
Conclusion
Developed by SIA Latekols, the LEK turbine offers excellent prospects for the world wind industry as a whole. Large-scale use of this radically new design for extracting power from the wind will make a significant change to wind energy production. The LEK design offers an excellent opportunity to make this industry more attractive in terms of the rate of return on investments.
In conclusion, it should be noted that SIA Latekols has also completed the entire project design and design documentation for the production of LEK turbines of 5, 30, 250, 600 and 850kW capacities.
Biography of the Author
Grigori Fedotov has a PhD in organisation of management from the Moscow Academy of Management, Russia. He has wide and relevant experience in engineering and management. For the past ten years he has worked at SIA Latekols, which specializes in studies, development and research on new means of receiving energy from a wind current. At the company, Grigori Fedotov is in charge of all works on development and testing prototypes of the new LEK rotor turbine.{/access}
