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 generation of an electric current, when two conductors of different metals are joined at their ends to form a circuit, with the two junctions kept at different temperatures.

The area of glass that fits in the window frame.

Space cooling achieved by shading, natural (unassisted, as opposed to forced) ventilation, conduction control, radiation, and evaporation; also called passive cooling.

A structure or media that absorbs heat.

A mainly flat surface for transmitting radiant energy.

An electrical device for converting alternating current to direct current. The chamber in a cooling device where water is separated from the working fluid (for example ammonia).

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

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.

For valves and fittings, implies that they are suitable for working pressures between 125 to 175 pounds per square inch.

The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second. It is the product of Voltage and Current (amperage).

The heat-transfer (exchanger) component of a heatpump, located outdoors, from which heat is collected in the heating mode, or expelled in the cooling mode.

The maximum energy demand or load in a specified time period.

A wheel that is designed to use the weight and/or force of moving water to turn it, primarily to operate machinery or grind grain.

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

The thermal energy used in an industrial process.

The power output of a device under specific or nominal operating conditions.

A product of crude oil that is used for space heating, diesel engines, and electrical generation.

The fine liquid or solid particles contained in combustion gases. The quantity and size of particulates emitted by cars, power and industrial plants, wood stoves, etc are regulated by the U.S. Environmental Protection Agency.

The loss of heat as the water circulates through a water heater tank and inlet and outlet pipes.