A system capable of rotating about one axis.

The arrangement, proportion, and design of windows in a building.

A turbine that is driven by high velocity jets of water or steam from a nozzle directed to vanes or buckets attached to a wheel. (A pelton wheel is an impulse hydroturbine).

A construction element used for ceiling support.

A device used to control temperatures; used to control the operation of heating and cooling devices by turning the device on or off when a specified temperature is reached.

The practice of using a single meter to measure consumption and generation of electricity by a small generation facility (such as a house with a wind or solar photovoltaic system). The net energy produced or consumed is purchased from or sold to the gener ...

The distance between similar points on successive waves.

A house built into the ground or slope of a hill, or which has most or all exterior surfaces covered with earth.

A class of power generator that is not a regulated utility and that has generating plants for the purpose of supplying electric power required in the conduct of their industrial and commercial operations.

The amount of energy derived from an electrical source per unit quantity of electricity passing through the source.2. Electrical potential; voltage.

The use of devices to limit or prevent the release of pollution into the atmosphere.

A heating system, such as a solar water heater or geothermal heatpump, in which the working fluid is heated and used directly; in an open-loop solar system, the domestic water is circulated in the collector loop.

The space within a building or structure that is normally occupied by people, and that may be conditioned (heated, cooled and/or ventilated).

The coldest months of the year; months where average daily temperatures fall below 65 degrees Fahrenheit creating demand for indoor space heating.

A way of joining photovoltaic cells by connecting positive leads to negative leads; such a configuration increases the voltage.

A unit or measure of electricity supply or consumption of 1,000 Watts over the period of one hour; equivalent to 3,412 Btu.

An idealized process in which a working fluid (water, air, ammonia, etc) successively changes its state (from a liquid to a gas and back to a liquid) for the purpose of producing useful work or energy, or transferring energy.

A type of motor that has a rotor with electrical windings connected through slip rings to the external power circuit. An external resistance controller in the rotor circuit allows the performance of the motor to be tailored to the needs of the system and ...

A water heater that heats water before it is directly distributed for end use as required; a demand water heater.

The transfer of heat through a material by the transfer of kinetic energy from particle to particle; the flow of heat between two materials of different temperatures that are in direct physical contact.