Курсовая работа: Planning of mobile complete set for a rural wind generator
Abstract
The aim of this thesis is to alleviate the chronic lack of electricity supply in the rural South African areas by designing a portable wind generator kit.
An extensive assessment on the rural village of Ga-Rampuru, in Limpopo Province, was conducted, to investigate the present needs, as well as the availability of resources both human and material that would be needed to construct and assemble the system. From the inventory of recyclable materials found during the investigation the author was more inclined to suggest the design of a wind turbine that could be assembled and maintained by the local artisans.
A two pole permanent magnet synchronous generator was designed using standard commercial magnets, which were later replaced by recyclable loudspeaker magnets that were found in the village. This was done to compare the output of the generator in both cases. All the designs were modelled in FEMM, a software package, to estimate the induced voltage and flux of the generators.
Using standard commercial magnets the simulated voltage and flux levels were 9.4, 5.1, 3.6V and 0.0489, 0.0186, 0.0175 Wb, respectively. Assuming a generator current rating of 1 amp this would yield 36 watts at the estimated average wind speed of 4 meters per second.
Then when these were substituted with recycled speaker magnets the generator yielded a voltage of 3.5V and a flux of 0.0171Wb. The estimated output power of the recycled generator was estimated to be 10.5W. This compared well with the power output from the commercial magnets generators.
From these preliminary results it is quite apparent that a viable generator can be designed from the recyclable magnetic components. The same design procedure as outlined in this thesis can be used to design larger recycled generators with larger outputs. The design of this wind turbine will obviously have a wide range of positive developmental benefits on the community of Ga-Rampuru.
The next stage was practical construction to validate of the simulation results. This however could not be realised in time.
Chapter 1. Introduction
1.1 The subject of the report
The aim of this thesis is to design a simple wind generator kit that can be easily assembled and installed by rural artisans. The kit will use recyclable materials that are found in the rural areas to ensure a cost effective and environmentally sustainable solution.
1.2 Background to research and investigation of rural electrification
“Electricity brings immeasurable benefits to human life. With electricity, comes lighting and the ability to extend the daylight hours, to study and to improve education. With electricity come cooling and heating and the ability to store food and cooking. At its extended level, electricity facilitates communications, transportation and production and paves the way for the eradication of poverty, industrialisation and ultimately the growth of our country’s economy”.[3]
Electricity is a basic necessity and access to it has a wide range of positive developmental benefits for communities [1] , yet, in 2001 2.8 million South African households still had no access to electricity [2] . The majority of these households are poor and live in remote places which are located far from the central business districts and the country’s electricity grid. And this makes it very expensive to connect them to the country’s electricity grid.
As a national initiative to improve the quality of life in South Africa, National Electrification Programme (NEP) aims to provide universal access to all South Africans by 2012 [4] . Hence, this has lead to the investigation of other safe, cost effective and environmentally friendly alternative methods of electrifying rural areas in South Africa.
Renewable energy resources such as wind and solar, are the fastest growing alternative means of providing a reasonable amount of energy at the point of demand. The Government of South Africa is also determined that renewable resources will be a major complement to the national mix [4] .
1.2.1 Ga-Rampuru, a typical rural South African village
Ga-Rampuru is a small village located in Limpopo Province in South Africa. The village is in a fairly rural mountainous area, which is situated some 58 odd kilometres from Polokwane, the provincial capital city. The area has sparsely populated households with some trading stores and schools. Most of the people in the village are unemployed and rely on agriculture for their subsistence.
People in the village have to travel long distances to collect wood or to purchase fuels like liquid petroleum gas (LPG) and kerosene to meet their cooking, lighting, refrigeration, infotainment and other needs. Figure 1 illustrates a picture of an LPG refrigerator in one of the trading store in Ga-Rampuru. This picture and others that will follow in this thesis we taken by the author during a visit at Ga-Rampuru last June vacation.
The supply of these fuels is both expensive and unpredictable. Additionally the problems related to the use of fuels such as kerosene are incidences concerning burned houses and respiratory problem for children who use kerosene candles for reading is well documented world wide [6] .
The author paid a visit to the Provincial ESKOM office to enquire about any plans to extend the grid to Ga-Rampuru village; and the Electrification Manager guaranteed that ESKOM has plans to ultimately electrify the whole country by 2012. However, further discussions with people from Ga-Rampuru dismissed the ESKOM Manager’s promises as empty. They contended that they had heard similar promises but they still lived in darkness.
It was the conclusion of the author that an alternative solution to the problem had to be devised. Some means of generating electric power to meet loads such as the refrigerator in figure 1, if only it could be an affordable design. The best design would clearly be one that uses local material and human resources.
1.2.2 Resource assessment
The author spent the next three weeks exploring the resources available in Ga-Rampuru that would support the design and sustainable construction of electricity generators.
To begin with Ga-Rampuru has two schools, namely Rampuru primary school and Seokeng secondary school, all which constitute a total population of roughly 1400 pupils. On average 30% of school leavers will continue to tertiary education, some will migrate to urban centres in search for jobs and a substantial number will remain in the village.
This village is endowed with adequate human capacity with intermediate levels of education. These would constitute a source of trainable technicians and potential consumers of locally manufactured products. There are also local mechanics who fix cars and some electrical appliances. These people will be easily trained as they have hands on experience.
Some of the people who left the village for jobs in the cities come back to settle down in the village and build big houses like the one indicated in Fig 2. This clearly indicates that this people can afford the electricity tariffs if they were to be supplied with power.
Moving further around the village there was evidence of old windmills used for pumping water. Figure 3 shows one of the windmills. These windmills operate satisfactorily providing enough water to the villagers. The presence of these windmills in this area is evidence that there is some wind resource in the area.
Further investigations took the author to various waste-dump sites and a range of disused old gadgets that could potentially be re-used, as shown in appendix A, were discovered. These included cables from an old car, loudspeaker magnets, drums and old machines that were used for grinding grain.
The other natural resource in the area (of course) is the sun but from the inventory of recyclable materials found during the investigation it is more inclined to suggest the design of a wind turbine.
1.3 Objectives of the report
In light of the above background, the main objective of this thesis is to design a small wind generator for Ga-Rampuru village using recyclable materials found in this village. The idea is to build an easily assembled and manufactured machine that can be build by the rural artisans. This wind generator must of course be cost effective.
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