A heat exchanger in which heat is recovered from the products of combustion.

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

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

A solar absorber surface that has high absorbtance at wavelengths corresponding to that of the solar spectrum and low emittance in the infrared range.

The conversion of heat into electricity by the use of thermocouples.

The cost of producing one additional unit of a product.

The compound (working fluid) used in air conditioners, heat pumps, and refrigerators to transfer heat into or out of an interior space. This fluid boils at a very low temperature enabling it to evaporate and absorb heat.

The process of implementing measures to reduce peak power demands on a system.

A device for measuring light intensity that works by converting light falling on, or reach it, to electricity, and then measuring the current; used in photometers.

Fuels that cannot be easily made or "renewed," such as oil, natural gas, and coal.

The process of changing from one physical state (solid, liquid, or gas) to another, with a necessary or coincidental input or release of energy.

Energy available from the movement of the wind across a landscape caused by the heating of the atmosphere, earth, and oceans by the sun.

Materials left over from making nuclear energy. Radioactive waste can living organisms if it is not stored safely.

Wood, used for fuel, that has been air dried so that it contains 15 to 20 percent moisture content (wet basis).

The process by which materials expel or release gasses.

Caulking and weatherstripping to reduce air infiltration and exfiltration into/out of a building.

A way of joining photovoltaic cells or modules by connecting positive leads together and negative leads together; such a configuration increases the current, but not the voltage.

The thermal energy used in an industrial process.

A structure or media from which heat can be absorbed or extracted.

An architectural design invented by Buckminster Fuller with a regular polygonal structure based on radial symmetry.