The rate at which heat is removed is proportional to the velocity of the air. Combustion air is required for fire. Fire is easily adjusted by controlling fresh air intake. Pumping water by windmills was familiar to rural Americans early in this century. Water About three-fourths of the Earth's surface is water.

The natural cycle of water evaporation and precipitation created by the sun is a force needed to sustain life on Earth. Many forms of energy can be realized from this movement of water in its natural cycle.

Below are a few examples: Electrical energy can be generated by the movement of water in different ways. Hydro-Electric Dams hold water above its natural level creating a head pressure needed to power generators.

Turbines have been designed to take advantage of the Mississippi River and the Gulf Stream. Ocean Thermal gradients are the temperature difference between surface and deep waters. In some parts of the world, heat engines can be powered this way.

Tidal power can harness ocean movement resulting from gravitational forces of the moon. Dams can trap water to be released through turbines. Turbines that take advantage of water movement in both directions are more efficient. Cooling with water is possible by exposing it to the clear night sky where heat is given up by radiation.

Ponds on flat roofs are used in this manner. Heat can also be lost through evaporation. Water sprayed on roofs is beneficial even in humid areas, but more efficient in arid areas.

Caution should be used in areas of scarce water or drainage problems. Thermal Inertia is the stabilizing of temperatures by a large body of water. Coastal, riverfront, and lakefront cities are known for their milder climates and refreshing breezes. The wind movement is generated by the temperature difference from water to land.

The temperature difference between day and night is much greater on land than over water. That is one reason why Alexandria is warmer in the summer and colder in the winter than New Orleans.

Thermal Storage by water is four times the capacity of concrete, brick or gravel. Each gallon of water can hold Btus of thermal energy. The heat in water is fairly evenly distributed by convection.

Cleaning water takes place through its movement. This movement causes it to drop the heavier impurities and gives it greater exposure to the sun and air. Algae and micro-organisms which live in the water also help to clean it. Plants need water as part of their food supply.

Water can be retained in cisterns or ponds for landscaping and greenhouse use. Conservation of water is important because it takes more and more energy to clean water and move it to your building.

Recycling of a fixed supply of water on, in, and around the Earth is a natural system. It can change states from solid to liquid to gas.

Gray water from your building can be reused before disposal. Earth Earth is an almost spherical body approximately 4, miles in radius. The center is occupied by a hot core 2, miles in radius which is surrounded by the 1, mile thick mantle. The outer crust is only 5 to 25 miles thick.

It is within a few inches above and below the ground surface that earth, air, and water mix in the presence of sunlight.

Here phenomena or processes of chemistry, osmosis, transpiration, decay, transmutation, and regeneration take place. We are absolutely dependent upon the workings within this fragile matrix. Fossil Fuels are formed and contained in the earth. They are a valuable energy source which is renewable only on an extremely protracted time scale measured in millions of years.

Cooling and Heating can be used by the thermal lag between surface temperatures and those below ground. At a depth of 15 feet below ground, the temperatures will be about three months behind the surface temperatures. In Lafayette, the average yearly deep ground temperature is around 68°F in the summer to 71°F in the winter.

Insulation value can be given to the earth by tempering heat gains or losses through roofs, walls, and floors.

Water pipes in the ground below the frost line are protected from freezing temperatures. Earth forms can be designed to protect buildings from wind and other harsh weather conditions, or they can be formed to channel air into the building. Geothermal energy is provided by subterranean movement of water in contact with the intense heat produced at the Earth's core.

This source can provide steam and hot water. Geopressure can be found deep in the ground. This pressure can move turbines to produce mechanical or electrical energy. Purification of water occurs as it percolates down through the soil where impurities are deposited.

This process is aided by aerobic and anaerobic bacteria in the soil that over time reduce most waste to a harmless state.

Building Materials can be obtained from the Earth at the site without or with less of the expense of manufacturing and transporting them. Stabilized earth, adobe blocks, rammed earth, earth floors, sod roofs, and mud surfacing are examples of on site, low cost building material potentials.

Vegetation It is important to understand the value of plant life on Earth. It is interesting that words plant and planet are so much alike. Photosynthesis takes place in the chlorophyll cells of green plants -- consuming carbon dioxide, producing carbohydrates, and freeing oxygen.

This relationship of sun and plants that created the biosphere around the Earth allows man and animals to survive. Biomass is the plant and animal material produced by photochemical reaction.

Fire, Heat and Light are the release of the sun's energy used in creating the wood when wood is burned. Free oxygen is added back by the chemical process during combustion. Chemically, a wood fire is the reversal of nature's growth process but at a much greater speed.

Care must be taken to provide complete combustion, otherwise pollutants will be released into the air. Methane is a colorless, odorless, flammable gas which is formed by the decomposition of organic waste products of living organisms on Earth.

Methane, the main component of natural gas, can be used as a heating fuel and for illumination. In addition, its by-product can be used as fertilizer. Alcohol can be obtained by a fermentation process producing Ethanol or by a distillation process creating Methanol.

does not change - net energy lost balances net energy gained within the system. There are various forms of energy sources. Most sources are traceable to the Sun. The traditional energy source, fossil fuels, received the initial energy from the light used by plants for photosynthesis and animal metabolic needs.

Organic matters from the plant and animal remains later turn into the fossil fuels Coal, oil and natural gas which are currently widely in use for energy supply. Some energy sources are renewable while others are non-renewable. Renewable energy sources are sources that are freely available and cannot be easily depleted while the non-renewable sources can run out and are often not freely available.

Some energy sources are non-polluting or have low pollution while others produce tremendous pollution as by-products of the transformation process that takes them to useful forms. Fossil fuels, for instance, has been noted for producing tremendous amount of green house gases GHGs which are heat trapping gases believed to be responsible for global warming with its attendant problems.

For more details visit the Climate Change section. To mitigate the effects of the climate change, there are increasing call and search for alternative energy sources. Alternative energy sources alternative to fossil fuels are sources producing little or no GHGs emissions while still meeting the current and future energy needs of the World.

The renewable energy sources described earlier on this page are alternative energy sources alternative to fossil fuels.

However, alternative energy can also be realized from cleaner processing of the dirty fossil fuels or from other sources such nuclear energy. Fossil fuels are fuels believed to have been formed from plants and animal remains of ancient times that have undergone significant decomposition.

They are mainly Coal, Crude Oil petroleum and Natural Gas. Other less common and more expensive to process ones are bituminous sands e. Canada's tar sands and oil shale. Electricity that powers several industrial installations and provided lighting for cities and communities are derived from these three sources.

The combustion of these fuels release GHGs, which contributes to climate change and global warning. Besides polluting the atmosphere, fossil fuels are non-renewable and are gradually being depleted. Natural Gas produces lesser amount of GHGs than Coal and Oil and besides, the abstraction, transportation and storage processes for Natural Gas are being improved upon to further reduce the GHGs emissions to the atmosphere.

Some technologies such as Clean Coal Technologies CCTs have been suggested to make the burning of coal cleaner as well. CCTs are, however, still being researched.

The most widely used source is hydroelectric power, which currently supplies some 6. Other non-polluting sources are solar energy, tidal energy, wave energy and wind energy.

Most non-polluting energy sources require a high capital investment but have low running costs. GEMET General Multilingual Environmental Thesaurus.

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Thematic Listings Hierarchical Listings INSPIRE Spatial Data Themes Alphabetic Listings Search Thesaurus. Query: Search. Translations Arabic. In addition to purchasing photovoltaic panels, a wind turbine, or a small hydropower system, you will need to invest in some additional equipment called " balance-of-system " to condition and safely transmit the electricity to the load that will use it.

This equipment can include:. See our page on balance-of-system equipment requirements for small renewable energy systems for more information on the additional equipment needed for stand-alone home energy systems.

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