INTER SCHOOL SCIENCE EXHIBITION
SOLAR UPDRAFT TOWER
Smarajit Paul Choudhury
This project would not have been possible without the help and guidance of our respected Principal Mrs. Panchali Roy and our concerned teacher Ms. Soma Sarkar. We sincerely thank them and our parents for their active cooperation in this project. Knowledge came hand in hand with our efforts in making our project.
2. The use of three old technologies
3. The technology
3.1. The collector
3.2. The energy storage
3.3. The chimney
3.4. The turbines
3.5. A 'hydroelectric power station for the desert
4. The prototype in Manzanares
5. Designing large solar chimneys
6. Energy Production Costs
The future of this earth and mankind substantially depends on our ability to slow down the population increase in the Third World by civilized means. The key is to increase the standard of living, to overcome the inhumane poverty and deprivation. To achieve this traditional means will not suffice any longer as exemplified by a "paradoxon": Those countries where agriculture provides more than 20 % of the gross national product are those also stricken by starvation!
Development requires mechanization and energy. Energy consumption increases proportionally to the gross national product or prosperity while simultaneously the population growth will decrease exponentially. Many developing countries possess hardly any energy sources and their population doubles every 15 to 30 years! The results are commonly known: Civil wars and fundamentalism. If these developing countries are provided with only a humane and viable minimum of energy the global energy consumption will drastically increase! Who could supply such an enormous amount of energy without an ecological breakdown (because poor countries cannot afford environmental protection) and without safety hazards (because they are not acquainted with the safety requirements for nuclear power plants) and without a rapid depletion of natural resources at the expense of future generations? The sun! Many of these countries are lavishly provided with solar radiation in their desert areas. This is common knowledge, stated already in Agenda 21 of the Rio-UN-conference, everybody is talking about it, and nobody does anything. Why? Because apparently it must be a well-kept secret that large-scale solar energy utilization is possible today and that it is affordable and competitive!
SCIENTIFIC PRINCIPLE INVOLVED
The use of three old technologies
Man learned to make active use of solar energy at a very early stage: greenhouses helped to grow food, chimney suction ventilated and cooled buildings and windmills ground corn and pumped water. The solar chimney's three essential elements - glass roof collector, chimney, and wind turbines - have thus been familiar from time immemorial A solar-thermal chimney simply combines them in a new way .
Air is heated by solar radiation under a low circular glass roof open at the periphery; this and the natural grounds below it form a hot air collector. Continuous 24 hours-operations is guaranteed by placing tight water-filled tubes under the roof. The water heats up during the daytime and emits its heat at night. These tubes are filled only once, no further water is needed. In the middle of the roof is a vertical chimney with large air inlets at its base. The joint between the roof and the chimney base is airtight. As hot air is lighter then cold air it rises up the chimney. Suction from the chimney then draws in more hot air from the collector, and cold air comes in from the outer perimeter. Thus solar radiation causes a constant updraught in the chimney. The energy this contains is converted into mechanical energy by pressure-staged wind turbines at the base of the chimney, and into electrical energy by...