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.

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

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

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

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

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

The number of degrees per day that the daily average temperature (the mean of the maximum and minimum recorded temperatures) is below a base temperature, usually 65 degrees Fahrenheit, unless otherwise specified; used to determine indoor space heating req ...

The process of removing a power plant, apparatus, equipment, building, or facility from operation.

A wall that carries ceiling rafters or roof trusses.

That fraction of annual energy demand supplied by a solar system.

A category of electric power producer established under the Public Utility Regulatory Policy Act (PURPA) of 1978, that includes small-power producers (SPP) who use renewable sources of energy such as biomass, geothermal, hydroelectricity, solar (thermal a ...

The control of the quality, quantity, and temperature-humidity of the air in an interior space.

A unit for measuring the extent that the outdoor daily average temperature (the mean of the maximum and minimum daily dry-bulb temperatures) falls below (in the case of heating, see Heating Degree Day), or falls above (in the case of cooling, see Cooling ...

The positive pole or electrode of an electrolytic cell, vacuum tube, etc. (see also sacrificial anode).

An opening; in solar collectors, the area through which solar radiation is admitted and directed to the absorber.

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

The space-conditioning load of a building.

A building architectural element (vestibule) with two airtight doors that reduces the amount of air infiltration and exfiltration when the exterior most door is opened.

The conversion of biomass into a gas, by biogasification (see above) or thermal gasification, in which hydrogen is produced from high-temperature gasifying and low-temperature pyrolysis of biomass.