The supportive structure of a building.

Costs that are repetitive and occur when an organization produces similar goods or services on a continuing basis.

This law states that no device can completely and continuously transform all of the energy supplied to it into useful energy.

A type of incandescent lamp that contains a halogen gas in the bulb, which reduces the filament evaporation rate increasing the lamp life. The high operating temperature and need for special fixtures limits their use to commercial applications and for use ...

A device that can be set to automatically turn appliances (lights) off and on at set times.

Electrical energy lost due to inherent inefficiencies in an electrical transmission and distribution system under specific conditions.

Parasitic resistance to current flow in a cell due to mechanisms such as resistance from the bulk of the semiconductor material, metallic contacts, and interconnections.

A heat engine of the reciprocating (piston) where the working gas and a heat source are independent. The working gas is compressed in one region of the engine and transferred to another region where it is expanded. The expanded gas is then returned to the ...

A method of depositing thin semiconductor films used to make certain types of solar photovoltaic devices. With this method, a substrate is exposed to one or more vaporized compounds, one or more of which contain desirable constituents. A chemical reaction ...

A water heater that uses electricity to move heat from one place to another instead of generating heat directly.

The shape of the phase power at a certain frequency and amplitude.

The length of time that a product or appliance is expected to meet a certain level of performance under nominal operating conditions; in a luminaire, the period after which the lumen depreciation and lamp failure is at 70% of its initial value.

The process of moving existing loads to off-peak periods.

A device for converting the flow of a fluid (air, steam, water, or hot gases) into mechanical motion.

A unit of air cooling capacity; 12,000 Btu per hour.

A tank used in a closed-loop solar heating system that provides space for the expansion of the heat transfer fluid in the pressurized collector loop.

As time increases from zero at the terminals of an inductor, the voltage comes to a particular value on the sine function curve ahead of the current. The voltage reaches its negative peak exactly 90 degrees before the current reaches its negative peak thu ...

The fundamental constituent of all vegetative tissue; the most abundant material in the world.

Defects, such as dangling bonds, induced in an amorphous silicon semiconductor upon initial exposure to light.

The direction, at any point on the earth that is geographically in the northern hemisphere, facing toward the South Pole of the earth. Essentially a line extending from the point on the horizon to the highest point that the sun reaches on any day (solar n ...