A method of predicting heating and/or cooling loads using instantaneous load calculation at different outdoor dry-bulb temperatures, and multiplying the result by the number of hours of occurrence of each temperature.

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

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 ...

A thin coating of a material applied to a photovoltaic cell surface that reduces the light reflection and increases light transmission.

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 ...

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

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

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

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 wall that carries ceiling rafters or roof trusses.

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

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

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.

Energy required to operate mechanical components of an energy system, or a source of energy or energy supply system to back-up another.

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.

A thermodynamic cycle using constant pressure, heat addition and rejection, representing the idealized behavior of the working fluid in a gas turbine type heat engine.

The space-conditioning load of a building.