Definitions - d

A Vertical Axis Wind Turbine design from the 1920s and 1930s by F.M. Darrieus, a French wind turbine designer.

Energy Efficiency is when you use less energy to accomplish the same task, for example heating your home or washing clothes. Using less energy by being more efficient means less air pollution and lower costs.

To save energy in your home, you can use weather stripping, solar water heating, passive solar or compact fluorescent light bulbs. Also when shopping for household appliances, look for the Energy Star to find appliances that use less energy and lower your electricity costs.

You can also reduce your heating and cooling costs by installing better insulation.

The number of consecutive days the stand-alone system will meet a defined load without solar energy input. This term is related to system availability.

Global warming is the name given to the theory that there is increase in the average temperature of the Earth surface air and oceans since the mid-20th century and its projected continuation.

The exact mechanism of warming is not precisely understood, although it is strongly suspected that Greenhouse gases are to blame, as increasing concentrations of such gases help trap heat in the atmosphere and so raise mean temperatures.

Wikipedia Entry

Perennial plants whose leaves die all at once (and usually fall) at the end of each growing season, to be replaced by new leaves at the next growing season. Most deciduous plants are broad-leaved, though a few, such as Larix laricina (Tamarack), have needles. Plants whose leaves live year-round are evergreen.

A Decomposer is an an organism whose ecological function involves the recycling of nutrients by performing the natural process of decomposition as it feeds on decaying organisms.

A Deep Cycle Battery is a battery that is capable of been discharged to nearly completely empty without long term negative effects on the life of the battery and its storage capacity.

The number of consecutive days the stand-alone system will meet a defined load without solar energy input. This term is related to system availability.

Someone who believes we need a radical transformation to a more sustainable society. Also, the belief environmental sustainability should have primacy over economic and social factors. Contrasts with light green and bright green.

Ability of materials to break down, by bacterial (biodegradable) or ultraviolet (photodegradable) action.

A fan-shaped alluvial deposit at a river mouth formed by the deposition of successive layers of sediment.

Mechanisms to manage the demand from customers in response to supply conditions.

Removal of nitrate and nitrate product from water to produce a quality that answeres common water standards.

The tendency of a population's growth rate to depend on its size, with an increase in population density corresponding to a decrease in growth. This self-regulating dynamic helps prevent extinction.

A colorless, pungent, gas that is extremely soluble in water and may be used as a refrigerant. It is also a fixed form of nitrogen that is suitable as fertilizer.

A widespread epidemic throughout an area, nation or the world.

The month having the combination of insolation and load that requires the maximum energy from the photovoltaic array.

Animals and plants that consume detritus (decomposing organic material), and in doing so contribute to decomposition and the recycling of nutrients.

The dew point is the temperature to which a given parcel of humid air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation temperature.

A pesticide used on citrus fruits.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

Green building (also known as green construction or sustainable building) is the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from siting to design, construction, operation, maintenance, renovation, and final deconstruction.

This practice expands and complements the classical building design concerns of economy, utility, durability, and comfort.

Sunlight falling directly upon a collector. Opposite of diffuse insolation.

Water that flows from the ground surface directly into streams, rivers, and lakes.

Air pollutants dropped by prevailing winds.

Dispatchability is the ability of a power plant to be turned on quickly to a desired level of output. Wind power plants are not dispatchable.

A Dispersion Trench is a method by which effluent after processing is distributed back into the environment in a way which reduces environmental impact. They often positioned so that the effluent is distributed by a grid of trench pipes into the soil directly; the aim being that the effluent never gets to the surface.

DERs. A variety of small, modular power-generating technologies that can be combined with energy management and storage systems and used to improve the operation of the electricity delivery system, whether or not those technologies are connected to an electricity grid.

The difference between maximum and minimum temperature over a period of 24 hours.

A unit used to measure the abundance of ozone in the atmosphere; one Dobson unit is the equivalent of 2.69 x 1016 molecules of ozone/cm².

A traditional window style with two glass-holding frames that slide past each other vertically.

Downcycling is the recycling of a material into a material of lesser quality. For example, when plastics are recycled they are turned into a lower grade quality plastic.

The process of accumulation and sinking of warm surface waters along a coastline. A change of air flow of the atmosphere can result in the sinking or downwelling of warm surface water. The resulting reduced nutrient supply near the surface affects the ocean productivity and meteorological conditions of the coastal regions in the downwelling area.

This is the total surface area, upstream of a point on a stream, where the water from rain, snowmelt, or irrigation not absorbed into the ground flows over the ground surface, back into streams, to finally reach that point.

1. The drop in the water table or level of water in the ground when water is being pumped from a well.
   
2. The amount of water used from a tank or reservoir.
3. The drop in the water level of a tank or reservoir.

The practice of spraying water directly on the base of plants so that less water is needed to make them grow.

Emissions of sulphur and nitrogen oxides that, in the absence of water in the atmosphere (i.e., rain), settle to the ground as particulate matter.

A type of farming practiced in semi-arid or dry grassland areas without irrigation using such approaches as fallowing, maintaining a finely broken surface, and growing drought-tolerant crops.

A crumbling and drying of wood that is caused by a fungus; turns wood into powder.

(water management) Accumulation of salts in soils, soil water and ground water; may be natural or induced by land clearing

Dryland systems are ecosystems characterised by a lack of water. They include cultivated lands, scrublands, shrublands, grasslands, savannas, semi-deserts and true deserts.

A device to which wind generator power flows when the system batteries are too full to accept more power, usually an electric heating element. This diversion is performed by a Shunt Regulator, and allows a Load to be kept on the Alternator or Generator.

Acidic bodies of water that contain many plants but few fish, due to the presence of great amounts of organic matter.