A solar collector that uses reflective surfaces to concentrate sunlight onto a small area, where it is absorbed and converted to heat or, in the case of solar photovoltaic (PV) devices, into electricity. Concentrators can increase the power flux of sunlig ...

A tubular material used to encase and protect one or more electrical conductors.

An electrochemical device that converts chemical energy directly into electricity.

Turbines in which the axis of the rotor's rotation is parallel to the wind stream and the ground.

A device used to maintain a specified humidity in a conditioned space.

The trapping of light by refraction and reflection at critical angles inside a semiconductor device so that it cannot escape the device and must be eventually absorbed by the semiconductor.

A computer software program that simulates energy consumption of commercial buildings; used for design and auditing purposes.

Large, flat boxes with glass covers and dark-colored metal plates inside that absorb and transfer solar energy to a heat transfer fluid.

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.

Transmit high-voltage electricity from the transformer to the electric distribution system.

A measure of the probability that a system demand will exceed capacity during a given period; often expressed as the estimated number of days over a long period, frequently 10 years or the life of the system.

The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.

A value that describes the ability of a material to conduct heat. The number of Btu that flow through 1 square foot of material, in one hour. It is the reciprocal of the R-Value (U-Value = 1/R-Value).

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

Sensible and latent heat contained in combustion gases and vapor emitted to the atmosphere.

A class of energy producer that produces both heat and electricity from a single fuel.

The measure of closeness in shape between a waveform and it's fundamental component.

As defined by the Comprehensive National Energy Act of 1992 (or the Energy Policy Act; EPAct): any organic matter from a plant which is planted for the exclusive purpose of being used to produce energy." This does not include wood or agricultural wastes o ...

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.

Glass, plastic panels, or plastic sheets that reduce air infiltration and some heat loss when attached to either the interior or exterior of existing windows.