PDF《WINDPUMPING》

WINDPUMPING Introduction Windpower technology dates back many centuries.

There are historical claims that wind machines which harness the power of the wind date back to the time of the ancient Egyptians. Hero of Alexandria used a simple windmill to power an organ whilst the Babylonian emperor, Hammurabi, used windmills for an ambitious irrigation project as early as the 17th century BC. The Persians built windmills in the 7th century AD for milling and irrigation and rustic mills similar to these early vertical axis designs can still be found in the region today. In Europe the first windmills were seen much later, probably having been introduced by the English on their return from the crusades in the middle east or possibly transferred to Southern Europe by the Muslims after their conquest of the Iberian Peninsula. It was in Europe that much of the subsequent technical development took place. By the late part of the 13th century the typical '

European windmill'

had been developed and this became the norm until further developments were introduced during the 18th century. At the end of the 19th century there were more than 30,000 windmills in Europe, used primarily for the milling of grain and water pumping. The first half of the 20th saw further development, particularly a move toward propeller type wind machines for electricity production. The major advances in the design of the windpump, however, took place in the USA. The technology was taken up and developed by the early pioneers or settlers who needed a method of lifting ground water for irrigation, for watering of livestock and later for providing water for steam locomotives which began to spread across the country. There were several significant technical developments to the commercial machines during this time;

the ability of the machine to turn into the prevailing wind automatically;

the development of a self governing mechanism which automatically turned the machine out of the wind when the wind velocity became high enough to cause damage;

various improvements in rotor design and general durability and the introduction of gearing mechanisms. The technology was soon taken up worldwide, especially in the newly settled arid regions, such as South Africa, Australia and Argentina, where previously a lack of water had always prevented settlement and economic development in remote areas. By the 1920'

s

6 million windpumps were being used in the USA alone and their manufacture and use had become commonplace on every continent. But the glory of the windpump was short-lived. With the advent of cheap fossil fuels in the 1950'

s and 1960'

s and the development of pumping technology the windpump became almost obsolete in the USA. Nowadays, with regular fuel crises and rising prices there has been a revival of interest in windpower but the windpump has yet to regain the status it held during its heyday. Windpumping for rural areas of the developing world There are manufacturers in several developing countries now producing windpumps. The uptake of wind machines for water pumping, however, has been generally very slow even though the technology is well suited to the demand of many regions of Africa, Asia and Latin America. Where they are used, the demand is for one of the following end uses: ? village water supplies ? irrigation ? livestock water supplies Water pumping is one of the most basic and widespread energy needs in rural areas of the world. It has been estimated that half the world'

s rural population does not have access to clean water supplies. Windpumping Practical Action