The minimum temperature at which combustion of a solid or fluid can occur.

Energy produced by the conversion of biomass directly to heat or to a liquid or gas that can be converted to energy.

The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.

Individual rooms or zones in a building where temperature is controlled separately from other rooms or zones.

An elementary particle of an atom with a negative electrical charge and a mass of 1/1837 of a proton; electrons surround the positively charged nucleus of an atom and determine the chemical properties of an atom.

A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).

A solar energy conversion device that has a bowl shaped dish covered with a highly reflective surface that tracks the sun and concentrates sunlight on a fixed absorber, thereby achieving high temperatures, for process heating or to operate a heat (Stirlin ...

The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net kilowatt-hour.

The unit price of a good or service estimated from some base year in order to provide a consistent means of comparison.

A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.

A type of heating appliance similar to a fireplace, but much more efficient and clean burning. They are made of masonry and have long channels through which combustion gases give up their heat to the heavy mass of the stove, which releases the heat slowly ...

Materials with various qualities that are applied to glass windows before installation. These coatings reduce radiant heat transfer through the window and also reflects outside heat and a portion of the incoming solar energy, thus reducing heat gain. The ...

In a given electrical circuit, the amount of current in amperes (i) is equal to the pressure in volts (V) divided by the resistance, in ohms (R).

The replacement of a non-functional or ineffective lamp with a new, more efficient lamp.

An electricity generating facility that uses geothermal energy.

The amount of heat that a material can absorb and store.

Energy output from a system that equals energy input.

The process of producing electricity by transforming other forms or sources of energy into electrical energy; measured in kilowatt-hours.

Thermosyphon systems use a separate storage tank located above the collector. Liquid warmed in the collector rises naturally above the collector, where it is kept until it is needed. The liquid can be either water or a glycol solution. If the fluid is wat ...

A solar water or space-heating system in which solar energy is collected, and/or moved by natural convection without using pumps or fans. Passive systems are typically integral collector/storage (ICS; or batch collectors) or thermosyphon systems. The majo ...