42 U.S. gallons (306 pounds of oil, or 5.78 million Btu).

A combustible gas created by anaerobic decomposition of organic material, composed primarily of methane, carbon dioxide, and hydrogen sulfide.

In reference to solar energy systems, the angle at which direct sunlight strikes a surface; the angle between the direction of the sun and the perpindicular to the surface. Sunlight with an incident angle of 90 degrees tends to be absorbed, while lower an ...

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.

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

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.

This is the voltage-ampere requirement of a device designed to convert electric energy to a non-electrical form.

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 component of a combustion device that regulates the amount of air entering the combustion chamber.

The presence of contaminants in the air in concentrations that prevent the normal dispersive ability of the air, and that interfere with biological processes and human economics.

Microorganisms that live in oxygen deprived environments.

An interior court to which rooms open.

The cost of producing electricity up to the point of the powerplant busbar.

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 ratio of light reflected by a surface to the light falling on it.

The use of direct, diffuse, or reflected sunlight to provide supplemental lighting for building interiors.

The annual solar savings of a solar building is the energy savings attributable to a solar feature relative to the energy requirements of a non-solar building.

A device that converts the mechanical energy of rotation into electricity based on electromagnetic induction. An electric voltage (electromotive force) is induced in a conducting loop (or coil) when there is a change in the number of magnetic field lines ...

The process of decomposing biomass with anaerobic bacteria to produce biogas.