Wind Farms

A wind farm or wind park is a collection of wind turbines. The areal extent of the wind farm depends on the radius R of the rotor blades (Figure 5-3). A wind turbine must have enough space around the post to allow the fan of the rotor blade to face in any direction. The minimum spacing between the posts of two equivalent wind turbines must be 2Reff to avoid collisions between rotor blades. If we consider the aerodynamics of wind flow, which is the factor that controls turbine spacing, the...

Point to Ponder Are synfuels desirable alternative energy sources

Like biomass and fossil fuels, synfuels provide energy by generating heat using combustion. Once again the combustion process produces carbon dioxide as a byproduct. Carbon dioxide is a greenhouse gas and sequestration becomes an issue. Sequestration is the capture and storing of greenhouse gases. For example, we can geologically sequester carbon dioxide by injecting it into a geologic formation such as a coal seam or an abandoned oil field. Unlike biomass, coal gasification and gas-to-liquid...

Brief History Of Energy Consumption

We decide how much electricity we will use to heat or cool our homes. We decide how far we will drive every day and the type of vehicle we will drive. Those of us in democracies choose leaders who create budgets that can support new energy initiatives or maintain a military capable of defending energy supply lines. Each of these decisions and many others impact the global consumption of energy and the demand for available natural resources. The purpose of...

Active Solar Energy

Active Solar Energy

Active solar energy refers to the design and construction of systems that collect and convert solar energy into other forms of energy such as heat and electrical energy. Active solar energy technologies are typically mechanical systems through a material. Metals have relatively high thermal conductivities. Heat Flow through Wall Figure 4-5. Thermal Conductivity of an Insulated Wall that are used to collect and concentrate solar energy. We will discuss solar heat collectors and a solar power...

Point to Ponder What has hindered the global adoption of nuclear energy

Nuclear energy is a long-term source of abundant energy that has environmental advantages. The routine operation of a nuclear power plant does not produce gaseous pollutants or greenhouse gases like carbon dioxide and methane. Despite its apparent strengths, the growth of the nuclear industry in many countries has been stalled by the public perception of nuclear energy as a dangerous and environmentally undesirable source of energy. This perception began with the use of nuclear energy as a...

Waves and Tides

The oceans are another solar-powered source of energy. The mechanical energy associated with waves and tides, and thermal energy associated with temperature gradients in the ocean can be used to drive electric generators. We consider each of these energy sources in this section. In our discussion of hydropower, we saw that water can generate power when it moves from a high potential energy state to a low potential energy state, like water flowing over a waterfall. If the moving water is an...

References

Aubrecht, Gordon J., 1995, Energy, 2nd Edition, Prentice-Hall, Inc., Upper Saddle River, New Jersey. Ausubel, J.H., 2000, Where is Energy Going The Industrial Physicist Feb. , pages 16-19. Bain, A., and Van Vorst, W.D., 1999, The Hindenburg tragedy revisited the fatal flaw found, International Journal of Hydrogen Energy, Volume 24, pages 399-403. Borbely, A. and Kreider, J.F., 2001, Distributed Generation The Power Paradigm for the New Millenium, CRC Press, New York, New York. Brennan, T.J.,...

Forecasts Schollnberger Energy

Forecasts of the 21st century energy mix show that a range of scenarios is possible. The forecast discussed here is based on W.E. Schollnberger's forecasts, which were designed to predict the contribution of a variety of energy sources to the 21st century energy portfolio. Schollnberger's forecast is worth studying because it uses more than one scenario to project energy consumption for the entire 21st century. Schollnberger considered the following three forecast scenarios A. Another Century...

Solar Power Tower

Figure 4-8 is a sketch of a solar power tower with a heliostat field. The heliostat field is a field of large, Sun-tracking mirrors called heliostats arranged in rings around a central receiver tower. The heliostats concentrate sunlight on a receiver at the top of the tower. The solar energy heats a fluid inside the receiver. Figure 4-9 is a sketch of the geometry of the Sun-tracking mirrors relative to the central receiving station. The heliostats must be able to rotate to optimize the...

Energy Options Fossil Energy

The literature contains several publications that present a description of the energy sources that are available or are expected to be available during the 21st century. Energy options known today include fossil fuels, nuclear energy, solar energy, renewable energy and alternative sources. These energy options are briefly described in the chapters that follow. Fossil fuels are sources of energy that were formed by the death, decay, and transformation, or diagenesis, of life. The term diagenesis...

Biomass Conversion

Biomass, particularly biological waste, appears to be a plentiful source of methane. A simple methane digester that converts biological feed such as dung to methane is shown in Figure 6-5. The screw agitator mixes the liquid slurry containing the feed. The mixing action facilitates the release of methane from the decaying biomass as a biomass conversion process. Methane trapped by the metal dome is recovered through the gas outlet. containing the feed. The mixing action facilitates the release...