A room heat delivery (or exchanger) component of a hydronic (hot water or steam) heating system; hot water or steam is delivered to it by natural convection or by a pump from a boiler.

The storage of heat energy during utility off-peak times at night, for use during the next day without incurring daytime peak electric rates.

A measure of the amount of light incident on a surface; measured in foot-candles or Lux.

The amount of solar radiation striking a surface per unit of time and area.

An electrochemical battery that uses lead and lead oxide for electrodes and sulfuric acid for the electrolyte.

A material used to seal gaps around windows and exterior doors.

This compound of nitrogen and oxygen is formed by the oxidation of nitric oxide (NO) which is produced by the combustion of solid fuels.

The wind speed with 50 percent probability of occurring.

Waste material from households and businesses in a community that is not regulated as hazardous.

A unit of measurement for the ability of a material to retard the diffusion of water vapor at 73.4 F (23 C). A perm, short for permeance, is the number of grains of water vapor that pass through a square foot of material per hour at a differential vapor p ...

A curve that indicates the number of hours per year that specific wind speeds occur.

The thermodynamic cycle that is an ideal standard for comparing performance of heat-engines, steam power plants, steam turbines, and heat pump systems that use a condensable vapor as the working fluid; efficiency is measured as work done divided by sensib ...

A coil of tungsten wire suspended in a vacuum or inert gas-filled bulb. When heated by electricity the tungsten "filament" glows.

An electrical inverter that inverts direct current electricity to alternating current electricity, and that uses another alternating current source, such as an electric power transmission and distribution network (grid), for voltage and frequency referenc ...

A material that can be used to store thermal energy as latent heat. Various types of materials have been and are being investigated such as inorganic salts, eutectic compounds, and parrafins, for a variety of applications, including solar energy storage ( ...

A type of lamp having a lens of heavy durable glass that focuses the light. They have longer lifetimes with less lumen depreciation than standard incandescents.

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 ...

The process of using heat that is rejected in one part of a cycle for another function or in another part of the cycle.

A salt, sodium sulfate decahydrate, that melts at 90 degrees Fahrenheit; a component of eutetic salts that can be used for storing heat.

The ratio of the percentage change in the quantity of a good or service demanded to the percentage change in the price.