The temperature at which a material ignites.

The measure of seasonal or annual efficiency of a residential heating furnace or boiler. It takes into account the cyclic on/off operation and associated energy losses of the heating unit as it responds to changes in the load, which in turn is affected by ...

A wall that carries ceiling rafters or roof trusses.

In a solar energy system, refers to all components other than the collector. In terms of costs, it includes design costs, land, site preparation, system installation, support structures, power conditioning, operation and maintenance costs, indirect storag ...

The action of light on a biological system that results in the dissociation of a substrate, usually water, to produce hydrogen.

A type of electric generator that produces alternating current that matches an existing power source.

A measure of the flow of current (in amperes) over one hour.

One quadrillion Btu. (1,000,000,000,000,000 Btu)

A type of heat pump that transfers heat in outdoor air to water for space or water heating.

The refrigerating effect in Btu/h produced by the difference in total enthalpy between a refrigerant liquid leaving the unit and the total enthalpy of the refrigerant vapor entering it. Generally measured in tons or Btu/h.

A component of a heating or ventilation appliance used to conduct fresh air into, or waste air or combustion gases out of, an appliance or interior space.

The temperature of a medium, such as gas or liquid, which comes into contact with or surrounds an apparatus or building element.

The demand on, or the power output of, an electrical system or any of its parts over an interval of time, as determined by the total number of kilowatt-hours divided by the units of time in the interval.

A chemical change in a substance that results from the passage of an electric current through an electrolyte. The production of commercial hydrogen by separating the elements of water, hydrogen, and oxygen, by charging the water with an electrical current ...

Two metals of different coefficients of expansion welded together so that the piece will bend in one direction when heated, and in the other when cooled, and can be used to open or close electrical circuits, as in thermostats.

The ratings under which specified appliances convert energy sources into useful energy, as determined by procedures established by the U.S. Department of Energy.

The chemical element commonly used as the dopant in solar photovoltaic device or cell material.

A fluid, such as methanol or ethylene glycol, added to vehicle engine coolant, or used in solar heating system heat transfer fluids, to protect the systems from freezing.

An interior wall made of water filled containers for absorbing and storing solar energy.

A standard unit of electrical power equal to one thousand watts, or to the energy consumption at a rate of 1000 Joules per second.