Energy and Environment

Energy and Environment

DOI: 10.4018/978-1-4666-4627-8.ch010
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Abstract

The “Energy and Environment” project is a mental exercise intended to assist the reader in thinking and communicating with the use of visual language. Inspiration for this project comes from the theme of energy (such as kinetic, potential, mechanical, electrical, chemical, light, radiant, nuclear, and heat energy) and a need for its conservation. It also tells about the environmental concerns related to energy production and use. Visual and verbal projects provide analogies and comparisons of some energy related processes and events to our everyday experiences.
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Project 1. Hydropower

People have been harnessing energy from hydropower for centuries but presently only about 7% of electricity produced in the United States and about 21% of the world’s electricity comes from hydropower. Hydroelectric plants take energy from water flowing from dams and rivers. There are now about 8,000 dams in the United States. The important parts of a hydroelectric plant are a dam (with a high or low head) and a large pipe called a penstock that carries water from the dam to a generator (usually located in a power house). The vertical distance from the water level to a power-producing turbine is called a head. This distance – elevation change – allows for converting potential energy into kinetic energy. A high-head dam (e.g., about 300 m – 1000 ft) can provide a large volume of water to a turbine, to supply energy for a generator and produce thousands of megawatts (MW) of energy. When there is a low-head dam (for instance, less than 30 m – 100 ft) the output, that means the water flow, depends on the diameter of the penstock. The main types of turbines are the impulse and the reaction turbines. The impulse turbine, for example, the Pelton or the Francis turbine, uses nozzles aimed at cupped blades, so water pushes a wheel with blades; this type of turbine can rotate with a speed up to 1300 rpm (revolutions per minute). The reaction turbine, for example, the Kaplan turbine turns the wheel according to the Newton’s third law, which states that mutual forces of action and reaction between two bodies are equal, opposite and collinear.

The author and illustrator David MacAulay (1989) designed a book entitled “Mill,” which shows visual explanation of the planning, construction, and operation typical of mills developed in New England throughout the nineteenth century. This book is helpful in understanding how to gain energy from water.

The following project can be designed as a comparison of advantages and disadvantages of various types of hydroelectric energy systems. Maybe you would like to make a model of a turbine, with Flash or a physical model made of cardboard. For tips, see Table 1.

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