Sathyajith Wind Energy

Fundamentals, Resource Analysis and Economics
1. Auflage 2006
ISBN: 978-3-540-30906-2
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 246 Seiten, eBook

Growing energy demand and environmental consciousness have re-evoked human interest in wind energy. As a result, wind is the fastest growing energy source in the world today. Policy frame works and action plans have already been for- lated at various corners for meeting at least 20 per cent of the global energy - mand with new-renewables by 2010, among which wind is going to be the major player. In view of the rapid growth of wind industry, Universities, all around the world, have given due emphasis to wind energy technology in their undergraduate and graduate curriculum. These academic programmes attract students from diver- fied backgrounds, ranging from social science to engineering and technology. Fundamentals of wind energy conversion, which is discussed in the preliminary chapters of this book, have these students as the target group. Advanced resource analysis tools derived and applied are beneficial to academics and researchers working in this area. The Wind Energy Resource Analysis (WERA) software, provided with the book, is an effective tool for wind energy practitioners for - sessing the energy potential and simulating turbine performance at prospective sites.

Zielgruppe

Research

Autoren/Hrsg.

Sathyajith, Mathew

Inhaltsverzeichnis

Basics of wind energy conversion.- Analysis of wind regimes.- Wind energy conversion systems.- Performance of wind energy conversion systems.- Wind energy and environment.- Economics of wind energy.

Leseproben

4 Wind energy conversion systems ( P. 89)

During its transition from the earlier day’s wind ‘mills’ to the modern wind electric generators, the wind energy conversion systems (WECS) have transformed to various sizes, shapes and designs, to suit the applications for which they are intended for. For example, at the inceptive stage of the technology, wind machines were used for grinding grains.

Hence these ancient machines had vertical axis with wind catching surfaces made of canvas or bundles of reeds. The mechanical power available at the shaft was utilized for grain milling. With the advent of technology, so-called ‘American wind mills’ were introduced in the 19th century. These systems were designed with multi bladed rotor, mechanically coupled with reciprocating piston pumps, which was appropriate for water pumping application. The era of wind electric generators started in 1890 with the construction of the turbine in Denmark for meeting the rural electricity demand.

The modern wind turbine is a sophisticated piece of machinery with aerodynamically designed rotor and efficient power generation, transmission and regulation components. Size of these turbines ranges from a few Watts to several Mega Watts. Modern trend in the wind industry is to go for bigger units of several MW capacities, as the system scaling up can reduce the unit cost of wind generated electricity.

Most of today’s commercial machines are horizontal axis wind turbines (HAWT) with three bladed rotors. Though research and development activities on vertical axis wind turbines (VAWT) were intense during the end of the last century, VAWT could not evolve as a reliable alternative to the horizontal axis machines.

The turbines may be grouped into arrays, feeding power to a utility, with its own transformers, transmission lines and substations. Stand-alone systems catering the needs of smaller communities are also common. As wind is an intermittent source of energy, hybrid systems with back up from diesel generators or photovoltaic panels are also popular in remote areas.

For the efficient and reliable performance of a WECS, all its components are to be carefully designed, crafted and integrated. In this chapter, we will discuss the constructional features of WECS giving emphasis to various components, systems and sub-systems. As off shore installations are getting prominence in the recent years, details of such turbines are also included. Wind powered water pumps, which are still relevant in remote rural areas, are also featured in this chapter.

Electricity generation is the most important application of wind energy today. The major components of a commercial wind turbine are:

1. Tower

2. Rotor

3. High speed and low speed shafts

4. Gear box

5. Generator

6. Sensors and yaw drive

7. Power regulation and controlling units

8. Safety systems

4.1.1 Tower

Tower supports the rotor and nacelle of a wind turbine at the desired height. The major types of towers used in modern turbines are lattice tower, tubular steel tower and guyed tower. Schematic views of these towers are shown in Fig. 4.2. The lattice towers are fabricated with steel bars joined together to form the structure as shown in the figure.