Wind Turbine Efficiency
Increasing of the Wind Turbine Efficiency by Using of the Air Draught Power
Tech Area / Field
- MAN-PDM/Plant Design and Maintenance/Manufacturing Technology
- NNE-EPP/Electric Power Production/Non-Nuclear Energy
- NNE-MEC/Miscellaneous Energy Conversion/Non-Nuclear Energy
3 Approved without Funding
Georgian Technical University, Georgia, Tbilisi
- Technische Universität Clausthal / Institut für Maschinenwesen, Germany, Clausthal
Project summaryOne of the actual problems of the modern power engineering is development of the ecologically pure power technologies. In this direction the high importance has the improvement of the wind turbines.
It is known, that one of serious lacks of wind turbines is the small efficiency. One of the reasons of it is that turbines (air screws) have a so-called non-working zone which corresponds to approximately 25-30 % of the wind turbine radius. In this zone the turbine efficiency is very low. It is caused because of small speeds of the corresponding section of the blade. For the purpose to increase the wind turbine efficiency it is expedient to use the air stream energy passing through the internal non-working blade-swept zone of the wind turbine. Besides the air stream loss it is observed on tip zones of the blades, caused by an overflowing of the air stream through blade tips.
On the other hand the interesting decision is the power station running by using the air stream energy from the sun rising upward trough the vertical chimney tower. Heating of the air occurs in the collector which is a big greenhouse. Transformation of energy occurs by means of the turbine located in the basis of the chimney tower. Such power station (Manzanares Solar Chimney Power Station) was constructed in the 1980s in Spain under direction of Professor Jurg Shlaich (company Schlaich Bergmann und Partners). Similar, but more powerful power station (Solar Chimney Power Station) is under construction in Australia.
The main lack of the so-called chimney power stations are its big dimensions and low efficiency. One of the opportunities of increasing the efficiency of such power stations is the increase of the charge of an air stream passing through the chimney tower. But it in its turn depends on the air parameters on the input and output of the tower.
As it has been told above for increasing of the efficiency of the wind turbine it is expedient to use more effectively the air stream energy, especially in the internal blade-swept area. For this purpose it is possible to consider the small diameter wind turbine ahead of the main wind turbine which will run faster frequency in the non-working area of the basic wind turbine. It would increase efficiency of the wind turbine by 10...15 %. It is possible other way of using of the air stream energy passing through the non-working area of the wind turbine. For this purpose it is possible to install the channel in the middle of the turbine and the additional wind turbine inside of it. Lack of such decision of the problem is complications of its design.
On the other hand the increase in the air consumption in the chimney tower power station would be possible by air pressure decline of on the chimney output. It is just possible by blow-through of air in the horizontal channel located on the output of the chimney tower. The Venturi tube type channel will provide acceleration of the air and according to Bernoulli law pressure decline. Due to the pressure decline an additional draft in the tower will arise. This physical effect is named as ejection effect.
As a result we come to conclusion, that it is expedient to use an air stream passing trough the central area of the wind turbine for increasing of the draft in the chimney tower station. As a result we will have combination of the common wind turbine and chimney tower power station. However it is necessary to notice, that in the proposed scheme there is not only simply hybridization of two types of power station but mutual addition and reduction of those lacks which had these installations separately.
The basic compound components of the proposed modernized wind turbine are: the wind turbine (the air screw), the air channel representing combination of the confuser and diffuser, chimney power, heating air collector, air turbine and generator. The collector is a greenhouse in which air is heated from the solar energy. The design of the wind turbine together with the air channel allows to be oriented in the wind direction. As a result the air stream in the chimney tower arises because of the convection phenomenon so as ejection effect. Such basic decision allows to provide almost continuous running of the wind power station. By means of special black materials absorbing a solar energy, will probably accumulate this energy and provide the convection even during the night period of the day.
Basic advantage of the presented wind turbine concept is to increase the efficiency and productivity of the power station. Besides by synthesis of two principles of transformation of the energy the mutual reduction of lacks of these principles, without increase of dimensions and essential complication of its design is provided. Particularly increases of the efficiency of the wind-solar power station it is provided by using wind power passing through the central part of the blade-swept area of the wind turbine for the acceleration of the air stream in the chimney tower by using of the ejection effect. It is necessary to pay attention also to the fact that combination of functions of the chimney tower and wind power installation pole expenses on construction of the structure is considerably cut down. It should be paid attention to the fact that the proposed basic decision allows to provide almost continuous running of the wind power station.
Participants of the project have sufficient research and a developmental experience on these subjects. It proves scientific publications and patents. It should be noted also, that by participants of the project has been investigated, designed and constructed wind turbine power station, presented at an exhibition of achievements of technology of Georgia "EXPO-GEORGIA 2006 ". Besides participants of this project have an experience in ISTC grants. Scientists keep in contact with the leading research and industrial firms in the world.
The purpose of the project is the investigation and development of the modernized wind power station, in which increasing of its efficiency by using of the air stream passing through a root area of the turbine, by ejection effect and by the solar-heated air stream passing through the inside of the chimney tower will be achieved. Within these project it is stipulated both the theoretical investigation and manufacturing of the test model for the purpose of a proving of the principle and effectiveness of the power station.
Investigation concerns to the applied researches category. The basic result of the project will be results of the investigation and the technological decision of the modernized wind power station. In particular: investigations about the increase of the efficiency of wind power station by use of the air stream passing through the root area of the turbine, and also by the solar-heated air stream passing inside the chimney tower, the project of the modernized wind power station, experimental model of the modernized wind power station and test results.
Uniqueness of the project is the increase of the efficiency of wind power station, that is expressed in its continuous running and high efficiency in contrast to the other similar wind power stations.