All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment.

Any material that can be burned to make energy.

Water heated for residential washing, bathing, etc.

Electric power plant or utility capacity on line and running at low power in excess of actual load.

A water heater that releases hot water from the top of the tank when a hot water tap is opened. To replace that hot water, cold water enters the bottom of the tank to ensure a full tank.

The amount of energy absorbed (or converted) by a solar collector (or photovoltaic cell or module) over a 15 minute period.

An electrical device that resists electric current flow.

A heat source, such as a space heater, used to provide more heat than that provided by a primary heating source.

The demand on an energy producing system; the energy consumption or requirement of a piece or group of equipment.

A system in which a working fluid is used over and over without introduction of new fluid, as in a hydronic heating system or mechanical refrigeration system.

A measure of the efficacy (efficiency) of lamps. It indicates the amount of light (lumens) emitted by the lamp for each unit of electrical power (Watts) used.

The device that reduces the pressure of liquid refrigerant thereby cooling it before it enters the evaporator coil in a heat pump.

The flow rate in these systems is 1/8 to 1/5 the rate of most solar water heating systems. The low-flow systems take advantage of stratification in the storage tank and theoretically allows for the use of smaller diameter piping to and from the collector ...

A smokestack or flue for exhausting the products of combustion from a combustion appliance.

Technologies that pertain to the generation of electricity.

A type of furnace in which fuel is spread, automatically or mechanically, across the furnace grate.

A closed-loop solar heating system in which the heat transfer fluid in the collector loop drains into a tank or reservoir whenever the booster pump stops to protect the collector loop from freezing.

A thermodynamic property of a substance, defined as the sum of its internal energy plus the pressure of the substance times its volume, divided by the mechanical equivalent of heat. The total heat content of air; the sum of the enthalpies of dry air and w ...

A complete lighting unit consisting of a lamp(s), housing, and connection to the power circuit.

In reference to solar photovoltaic cell manufacure, a method of growing a large-size, high-quality crystal whereby coils heat a polycrystalline ingot placed atop a single-crystal seed. As the coils are slowly raised the molten interface beneath the coils ...