In modern wind turbines , kinetic energy in the wind is converted to rotational energy and then to electrical energy. This electricity is then conditioned and—in most cases—sent into the utility grid. In some parts of the country, wind energy has become cost-competitive with conventional sources of electricity generation.
There are a growing number of wind generators available with capacities ranging from a few hundred watts powering small off-grid homes, sailboats, etc. Wind generators are certainly most effective in areas with consistent, high-speed winds. Trees, buildings, and topography can slow winds down tremendously. In the United States, the best wind resources are generally near the coasts off-shore or on the Plains.
DOE, NREL, and others have developed wind resource maps for the country and some states have developed more detailed maps. Proper location of wind turbines is critical. Because there can be wide variations in wind speed over small distances, best practices often call for monitoring wind resources at a site or several potential sites for a year or more.
With smaller generators several kilowatts , turbines should typically be mounted 30—50 feet above the next highest object in a foot radius trees, buildings, etc.
Larger generators are centered feet or more off the ground where wind speeds are higher and less turbulent. Because most electric energy is used in buildings, many people have explored mounting wind turbines on top of buildings. This is often not a viable strategy because of the weight, vibrations, torque, and noise of the generators.
To get access to higher wind speeds, generators should be positioned well above nearby buildings. There are some wind generator products, however, specifically designed for mounting on buildings. They are usually small typically Watts or less and are still subject to wind speed and turbulence limitations.
While small, building-mounted turbines can be appealing to designers, larger turbines located far above buildings and other obstructions are much more effective with respect to electricity generation. Biomass power generation typically refers to the combustion of plant material to power turbines which—in turn—generate electricity. The term biofuel generally refers to a fuel derived from plant material biomass that can be used in lieu of conventional fossil fuels.
The oldest use of biomass energy is burning wood to keep warm. This is still quite common in homes today, and there are also more advanced boiler systems that burn wood to heat water for use in homes or larger buildings.
Some of these devices are designed to burn wood pellets rather than larger pieces of wood. Wood pellets are small less than one inch pieces of processed biomass from a variety of sources wood chips, sawdust, waste from wood processing, etc. Pellet-burning appliances typically have hoppers that feed the fuel to the firebox at a controlled rate—making pellet burning easier to control than some other types of biomass appliances. GOV Energy Saver pages. On larger scales, many timber and agricultural industries burn wood and agricultural waste to obtain useful heat—the heat can be used directly or used to power turbines to generate electricity.
When the biomass fuel is inexpensive—especially when it is a waste product—such power generation can be very cost-effective. As with burning of fossil fuels, burning biomass releases carbon dioxide and other pollutants. Because the carbon in biomass has quite recently been absorbed from the atmosphere, if the biomass resource is managed sustainably there may be little net-emissions of carbon dioxide. This closed carbon cycle, however, does not necessarily include any energy needed to cultivate, harvest, and process the biomass.
In addition to pollutants, opponents of biomass generation cite potential effects on regional agriculture or forestry. With growing demand for biomass, there may be pressure to harvest resources in less sustainable ways. As described above, biofuels are fuels derived from biomass that can be used in place of conventional fossil fuels. The two most common biofuels are ethanol and biodiesel.
Ethanol is currently used in gasoline mixtures to power many automobiles. Most of this ethanol comes from the fermentation of sugars found in food crops, primarily corn. Federal incentives make this cost-effective, but there is growing concern that using ethanol derived from fermentation of corn sugars is not sustainable; there may be more energy needed to cultivate, harvest, and process the material than is contained in the final fuel produced.
Other ethanol production strategies—using cellulosic material rather than sugars—can derive ethanol from wood chips, leaves, agricultural waste, and similar material. These show promise with respect to sustainability , but they currently have substantially higher costs see EERE Newsletter for more information. Biodiesel is made by converting natural oils—usually vegetable oils—into usable fuels. The fuel can be used in many engines or combustion appliances designed for diesel or no.
The appliances typically need no or minor adjustments, though sometimes a blend of biodiesel and petroleum results in best operation. These reports include site temperature profile, site consumption summary, project summary, zone summary, climate summary, site humidity profile, HVAC sizing summary, model assessment, and more. Simergy is another good energy modeling software. The standard version which is free comes with a trial of features of professional version for 28 days.
So for first 28 days, you can enjoy all its features for free and then continue using it with feature restrictions. I am not sure which features are for trial as there is no clear comparative description of the two versions. Energy3D is another free building energy modeling software for Windows. It basically lets you design different types Building Designs , Photovoltaics PV design , Concentrated solar power CSP design of projects and then perform energy analysis on them.
You can use some preloaded examples of simple buildings, complex buildings, photovoltaic systems, etc. You can draw a model using components like wall, window, pyramid roof, door, a human figure, tree, solar panel rack, etc. Other tools to make adjustments include rotate, resize, move, spin view, select, zoom, etc.
And, you can setup parameters for your model including date, time, place, latitude, thermostat, etc. Energy3D is the simplest energy modeling software in this list. Although it provides quite basic tools for energy modeling as compared to other mentioned software, it does what it does really well.
Home Page. Download Page. About Us. Provide details to get this offer. Cookies This site uses cookies: Find out more. In the coming decades, the alternative energy technology industries will undergo unprecedented growth and will represent a significant component of the U.
The replacement of conventional fossil fuel and nuclear fission energy resources by renewable-energy sources will mandate that industries, academia, and research institutions provide immediate technological solutions to curb global environ- mental pollution. To mitigate global environmental and atmospheric pollution and to accelerate technological growth, it is imperative that international academia keep up with industry by educating carrier professionals to meet these imminent challenges.
In the very near future, global economies will face enormous challenges that they will need to resolve, increasing the ever-growing need for ecologically friendly renewable- energy resources.
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