Glossary
E-F
Last Updated Monday, July 24, 2000
compiled by Nick Sundt

E, F

E

Earth Berm - A mound of dirt next to exterior walls to provide wind protection and insulation. (Source: US Department of Energy, 1999a).

Earth Cooling Tube - A long, underground metal or plastic pipe through which air is drawn. As air travels through the pipe it gives up some of its heat to the soil, and enters the house as cooler air. (Source: US Department of Energy, 1999a).

Earth-Coupled Ground Source (Geothermal) Heat Pump - A type of heat pump that uses sealed horizontal or vertical pipes, buried in the ground, as heat exchangers through which a fluid is circulated to transfer heat. (Source: US Department of Energy, 1999a).

Earth Sheltered Houses - Houses that have earth berms around exterior walls. (Source: US Department of Energy, 1999a).

Earth Summit - The shorthand name for the United Nations Conference on Environment and Development held in Rio de Janeiro in 1992, so-called because of the exceptional number of world leaders and heads of state that attended. (Source: Global Environment Facility, 2000a).

Easement - An incorporated right, liberty, privilege, or use of another entity's property, distinct from ownership, without profit or compensation; a right-of-way. (Source: US Department of Energy, 1999a).

Eccentric - A device for converting continuous circular motion into reciprocating rectilinear motion. (Source: US Department of Energy, 1999a).

economic efficiency - A term that refers to the optimal production and consumption of goods and services. This generally occurs when prices of products and services reflect their marginal costs. Economic efficiency gains can be achieved through cost reduction, but it is better to think of the concept as actions that promote an increase in overall net value (which includes, but is not limited to, cost reductions). (Source: California Energy Commission, 1999a.)

Economic instruments - In contrast to regulation which set rules to control the behavior of resources users, governments can also use economic instruments to sensitize producers and consumer to the need for responsible use of environmental resources and avoidance of pollution, resource destruction and waste. Economic instruments, such as taxes, charges, subsidies, deposit/refund schemes and tradable permits, achieve their goals through the use of market forces by correcting the price structure and internalizing environmental and social costs. (Source: Global Environment Facility, 2000a).

economies of sale - Economies of scale exist where the industry exhibits decreasing average long-run costs with size. (Source: California Energy Commission, 1999a.)

Economizer - A heat exchanger for recovering heat from flue gases for heating water or air. (Source: US Department of Energy, 1999a).

ecosystem - The interacting system of a biological community and its nonliving environmental surroundings. (Source: Carbon Dioxide Information Analysis Center, 1990a).

eddy - A circular movement of water or air that is formed where currents pass obstructions or between two adjacent currents that are flowing counter to each other. (Source: Carbon Dioxide Information Analysis Center, 1990a).

EER (Energy Efficiency Ratio) - The ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions. (Source: California Energy Commission, 1999a.)

Effective Capacity - The maximum load that a device is capable of carrying. (Source: US Department of Energy, 1999a).

Efficacy - The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy value, the higher the energy efficiency. (Source: US Department of Energy, 1999a).

Efficiency - Under the First Law of Thermodynamics, efficiency is the ratio of work or energy output to work or energy input, and cannot exceed 100 percent. Efficiency under the Second Law of Thermodynamics is determined by the ratio of the theoretical minimum energy that is required to accomplish a task relative to the energy actually consumed to accomplish the task. Generally, the measured efficiency of a device, as defined by the First Law, will be higher than that defined by the Second Law. (Source: US Department of Energy, 1999a).

Efficiency (Appliance) Ratings - A measure of the efficiency of an appliance's energy efficiency. (Source: US Department of Energy, 1999a).

El Nino - An irregular variation of ocean current that from January to March flows off the west coast of South America, carrying warm, low-salinity, nutrient-poor water to the south. It does not usually extend farther than a few degrees south of the equator, but occasionally it does penetrate beyond 12 degrees S, displacing the relatively cold Peru Current. The effects of this phenomenon are generally short-lived, and fishing is only slightly disrupted. Occasionally (in 1891, 1925, 1941, 1957 - 58, 1965, 1972 - 73, 1976, and 1982 - 83), the effects are major and prolonged. Under these conditions, sea surface temperatures rise along the coast of Peru and in the equatorial eastern Pacific Ocean and may remain high for more than a year, having disastrous effects on marine life and fishing. Excessive rainfall and flooding occur in the normally dry coastal area of western tropical South America during these events. Some oceanographers and meteorologists consider only the major, prolonged events as El Nino phenomena rather than the annually occurring weaker and short-lived ones. The name was originally applied to the latter events because of their occurrence at Christmas time. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Elasticity of Demand - The ratio of the percentage change in the quantity of a good or service demanded to the percentage change in the price. (Source: US Department of Energy, 1999a).

Electric Rate Schedule - A statement of the electric rate and the terms and conditions governing its application, including attendant contract terms and conditions that have been accepted by a regulatory body with appropriate oversite authority. (Source: US Energy Information Administration, 1999b)

electric resistance heater - A device that produces heat through electric resistance. For example, an electric current is run through a wire coil with a relatively high electric resistance, thereby converting the electric energy into heat which can be transferred to the space by fans. (Source: California Energy Commission, 1999a.)

electric radiant heating - A heating system in which electric resistance is used to produce heat which radiates to nearby surfaces. There is no fan component to a radiant heating system. (Source: California Energy Commission, 1999a.)

Electric Utility Restructuring - With some notable exceptions, the electric power industry historically has been composed primarily of investor-owned utilities. These utilities have been predominantly vertically integrated monopolies (combining electricity generation, transmission, and distribution), whose prices have been regulated by State and Federal government agencies. Restructuring the industry entails the introduction of competition into at least the generation phase of electricity production, with a corresponding decrease in regulatory control. Restructuring may also modify or eliminate other traditional aspects of investor-owned utilities, including their exclusive franchise to serve a given geographical area, assured rates of return, and vertical integration of the production process. (Source: US Energy Information Administration, 1997a.)

Electrical Energy - The energy of moving electrons. (Source: US Department of Energy, 1999a).

Electrical Charge - A condition that results from an imbalance between the number of protons and the number of electrons in a substance. (Source: US Department of Energy, 1999a).

Electrical System - All the conductors and electricity using devices that are connected to a source of electromotive force (or generator). (Source: US Department of Energy, 1999a).

Electrical System Energy Losses - A measure of the amount of energy lost during the generation, transmission, and distribution of electricity. (Source: US Department of Energy, 1999a).

Electric Circuit - The path followed by electrons from a generation source, through an electrical system, and returning to the source. (Source: US Department of Energy, 1999a).

Electric Energy - The amount of work accomplished by electrical power, usually measured in kilowatt-hours (kWh). One kWh is 1,000 Watts and is equal to 3,413 Btu. (Source: US Department of Energy, 1999a).

Electric Furnace - An air heater in which air is blown over electric resistance heating coils. (Source: US Department of Energy, 1999a).

Electricity Generation - The process of producing electricity by transforming other forms or sources of energy into electrical energy; measured in kilowatt-hours. (Source: US Department of Energy, 1999a).

Electric Rate - The unit price and quantity to which it applies as specified in a rate schedule or contract. (Source: US Department of Energy, 1999a).

Electric Rate Schedule - A statement of the electric rate(s), terms, and conditions for electricity sale or supply. (Source: US Department of Energy, 1999a).

Electric System - The physically connected generation, transmission, and distribution facilities and components operated as a unit. (Source: US Department of Energy, 1999a).

Electric System Loss(es) - The total amount of electric energy loss in an electric system between the generation source and points of delivery. (Source: US Department of Energy, 1999a).

Electric Power Plant - A facility or piece of equipment that produces electricity. (Source: US Department of Energy, 1999a).

Electric Power Transmission - The transmission of electricity through power lines. (Source: US Department of Energy, 1999a).

Electric Resistance Heating - A type of heating system where heat, resulting when electric current flows through an "element" or conductor, such as Nichrome, which has a high resistance, is radiated to a room. (Source: US Department of Energy, 1999a).

Electric Utility - A corporation, person, agency, authority or other legal entity that owns and/or operates facilities for the generation, transmission, distribution or sale of electricity primarily for use by the public. (Source: US Department of Energy, 1999a).

Electric Utility Sector - Those privately or publicly owned establishments that generate, transmit, distribute, or sell electricity. (Source: US Department of Energy, 1999a).

Electric Vehicles - A battery-powered electrically driven vehicle. (Source: US Department of Energy, 1999a).

Electrochemical Cell - A device containing two conducting electrodes, one positive and the other negative, made of dissimilar materials (usually metals) that are immersed in a chemical solution (electrolyte) that transmits positive ions from the negative to the positive electrode and thus forms an electrical charge. One or more cells constitute a battery. (Source: US Department of Energy, 1999a).

Electrode - A conductor that is brought in conducting contact with a ground. (Source: US Department of Energy, 1999a).

Electrolysis - A chemical change in a substance that results from the passage of an electric current through an electrolyte. The production of commercial hydrogen by separating the elements of water, hydrogen, and oxygen, by charging the water with an electrical current. (Source: US Department of Energy, 1999a).

Electrolyte - A nonmetallic (liquid or solid) conductor that carries current by the movement of ions (instead of electrons) with the liberation of matter at the electrodes of an electrochemical cell. (Source: US Department of Energy, 1999a).

Electromagnetic Energy - Energy generated from an electromagnetic field produced by an electric current flowing through a superconducting wire kept at a specific low temperature. (Source: US Department of Energy, 1999a).

Electromagnetic Field (EMF) - The electrical and magnetic fields created by the presence or flow of electricity in an electrical conductor or electricity consuming appliance or motor. (Source: US Department of Energy, 1999a).

Electromotive Force - The amount of energy derived from an electrical source per unit quantity of electricity passing through the source. (Source: US Department of Energy, 1999a).

Electron - 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. (Source: US Department of Energy, 1999a).

Electronic Ballast - A device that uses electronic components to regulate the voltage of fluorescent lamps. (Source: US Department of Energy, 1999a).

Electron Volt - The amount of kinetic energy gained by an electron when accelerated through an electric potential difference of 1 Volt; equivalent to 1.603 x 10^-12; a unit of energy or work; abbreviated as eV. (Source: US Department of Energy, 1999a).

Electrostatic Precipitator - A device used to remove particulate matter from the waste gasses of a combustion power plant. (Source: US Department of Energy, 1999a).

Ellipsoidal Reflector Lamp - A lamp where the light beam is focused 2 inches ahead of the lamp reducing the amount of light trapped in the fixture. (Source: US Department of Energy, 1999a).

Emission Factor - A measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process. (Source: US Department of Energy, 1999a).

emissions - Materials (gases, particles, vapors, chemical compounds, etc.) that come out of smokestacks, chimneys, and tailpipes. (Source: Carbon Dioxide Information Analysis Center, 1990a).

emissions coefficient/factor - A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g., grams of carbon dioxide emitted per barrel of fossil fuel consumed).(Source: US Environmental Protection Agency, 1999a)

emissions inventory - A list of air pollutants emitted into a community’s, state’s, nation’s, or the Earth’s atmosphere in amounts per some unit time (e.g. day or year) by type of source. An emission inventory has both political and scientific applications.(Source: US Environmental Protection Agency, 1999a)

Emissions Trading (general) - With an emissions trading system, a regulatory agency specifies an overall level of pollution that will be tolerated (a cap) and then uses allowances to develop a market to allocate the pollution among sources of pollution under the cap. Emissions permits or allowances become the currency of the market, as pollution sources are free to buy, sell, or otherwise trade permits based on their own marginal costs of control and the price of the permits. In no case can total emissions exceed the cap. (Source: US Energy Information Administration, 1997a.)

emissions trading (UN Climate Convention) - The Kyoto Protocol of the UN Framework Convention on Climate Change establishes a mechanism whereby Parties with emissions commitments may trade their emission allowances with other Parties. The aim is to improve the overall flexibility and economic efficiency of making emissions cuts. (Source: UN Climate Change Secretariat, 1999a)

Emissivity - The ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area; expressed as a number between 0 and 1. (Source: US Department of Energy, 1999a).

emittance - The emissivity of a material, expressed as a fraction. Emittance values range from 0.05 for brightly polished metals to 0.96 for flat black paint. (Source: California Energy Commission, 1999a.)

Enclosure - The housing around a motor that supports the active parts and protects them. They come in different varieties (open, protected) depending on the degree of protection required. (Source: US Department of Energy, 1999a).

Endothermic - A heat absorbing reaction or a reaction that requires heat. (Source: US Department of Energy, 1999a).

End Use - The purpose for which useful energy or work is consumed. (Source: US Department of Energy, 1999a).

Energize(d) - To send electricity through a electricity transmission and distribution network; a conductor or power line that is carrying current. (Source: US Department of Energy, 1999a).

energy - The capacity for doing work as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy). Energy has several forms, some of which are easily convertible and can be changed to another form useful for work. Most of the world’s convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical or other means in order to accomplish tasks. In the United States, electrical energy is often measured in kilowatt-hours (kWh), while heat energy is often measured in British thermal units (Btu).(Source: US Environmental Protection Agency, 1999a)

Energy Audit - A survey that shows how much energy you use in your house or apartment. It will help you find ways to use less energy. (Source: US Department of Energy, 1999a).

energy balance models - An analytical technique to study the solar radiation incident on the Earth in which explicit calculations of atmospheric motions are omitted. In the zero-dimensional models, only the incoming and outgoing radiation is considered. The outgoing infrared radiation is a linear function of global mean surface air temperature, and the reflected solar radiation is dependent on the surface albedo. The albedo is a step function of the global mean surface air temperatures, and equilibrium temperatures are computed for a range of values of the solar constant. The one-dimensional models have surface air temperature as a function of latitude. At each latitude, a balance between incoming and outgoing radiation and horizontal transport of heat is computed. (Abbreviated as EBM.) (Source: Carbon Dioxide Information Analysis Center, 1990a).

Energy Charge - That part of an electricity bill that is based on the amount of electrical energy consumed or supplied. (Source: US Department of Energy, 1999a).

energy conservation - Reduction or elimination of unnecessary energy use and waste. See energy-efficiency.(Source: US Environmental Protection Agency, 1999a)

Energy Crops - Crops grown specifically for their fuel value. These include food crops such as corn and sugarcane, and nonfood crops such as poplar trees and switchgrass. Currently, two energy crops are under development: short-rotation woody crops, which are fast-growing hardwood trees harvested in 5 to 8 years; and herbaceous energy crops, such as perennial grasses, which are harvested annually after taking 2 to 3 years to reach full productivity. (Source: US Department of Energy, 1999a).

Energy Density - The ratio of available energy per pound; usually used to compare storage batteries. (Source: US Department of Energy, 1999a).

energy-efficiency - The ratio of the useful output of services from an article of industrial equipment to the energy use by such an article; for example, vehicle miles traveled per gallon of fuel (mpg).(Source: US Environmental Protection Agency, 1999a)

Energy Efficiency Ratio (EER) - The measure of the instantaneous energy efficiency of room air conditioners; the cooling capacity in Btu/hr divided by the watts of power consumed at a specific outdoor temperature (usually 95 degrees Fahrenheit). (Source: US Department of Energy, 1999a).

Energy Efficient Mortgages - A type of home mortgage that takes into account the energy savings of a home that has cost-effective energy saving improvements that will reduce energy costs thereby allowing the homeowner to more income to the mortgage payment. A borrower can qualify for a larger loan amount than otherwise would be possible. (Source: US Department of Energy, 1999a).

Energy Factor (EF) - The measure of overall efficiency for a variety of appliances. For water heaters, the energy factor is based on three factors: 1) the recovery efficiency, or how efficiently the heat from the energy source is transferred to the water; 2) standby losses, or the percentage of heat lost per hour from the stored water compared to the content of the water: and 3) cycling losses. For dishwashers, the energy factor is defined as the number of cycles per kWh of input power. For clothes washers, the energy factor is defined as the cubic foot capacity per kWh of input power per cycle. For clothes dryers, the energy factor is defined as the number of pounds of clothes dried per kWh of power consumed. (Source: US Department of Energy, 1999a).

Energy End-Use Sectors - Major energy consuming sectors of the economy. The Commercial Sector includes commercial buildings and private companies. The Industrial Sector includes manufacturers and processors. The Residential Sector includes private homes. The Transportation Sector includes automobiles, trucks, rail, ships, and aircraft. (Source: US Department of Energy, 1999a).

Energy Factor (water heater terminology) - The efficiency of storage water heaters is indicated by its Energy Factor (EF), which is based on an average hot water consumption of 64 gallons/day. The higher the EF, the more efficient the water heater. (Source: Lawrence Berkeley Laboratory, 1999)

Energy Guide Labels - The labels placed on appliances to enable consumers to compare appliance energy efficiency and energy consumption under specified test conditions as required by the Federal Trade Commission. (Source: US Department of Energy, 1999a).

Energy Intensity - The relative extent that energy is required for a process. (Source: US Department of Energy, 1999a).

energy management system - A control system (often computerized) designed to regulate the energy consumption of a building by controlling the operation of energy consuming systems, such as the heating, ventilation and air conditioning (HVAC), lighting and water heating systems. (Source: California Energy Commission, 1999a.)

Energy Policy Act of 1992 (EPAct) - A comprehensive legislative package that mandates and encourages energy efficiency standards, alternative fuel use, and the development of renewable energy technologies. Public Law 102-486, October 24th, 1992. Also authorized the Federal Energy Regulatory Commission (FERC) to order the owners of electric power transmission lines to transmit or "wheel" power for power generators including electric utilities, federal power marketing authorities, and exempt wholesale generators. (Source: US Department of Energy, 1999a).

energy quality - Ability of a form of energy to do useful work. High-temper-ature heat and the chemical energy in fossil fuels and nuclear fuels are concentrated high quality energy. Low-quality energy such as low-temperature heat is dispersed or diluted and cannot do much useful work.(Source: US Environmental Protection Agency, 1999a)

energy reserves - The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost. (Source: California Energy Commission, 1999a.)

energy resources - Everything that could be used by society as a source of energy. (Source: California Energy Commission, 1999a.)

Energy Service Company (ESCO) - A company that specializes in undertaking energy efficiency measures under a contractual arrangement whereby the ESCO shares the value of energy savings with their customer. (Source: US Department of Energy, 1999a).

Energy Storage - The process of storing, or converting energy from one form to another, for later use; storage devices and systems include batteries, conventional and pumped storage hydroelectric, flywheels, compressed gas, and thermal mass. (Source: US Department of Energy, 1999a).

enhanced greenhouse effect - The concept that the natural greenhouse effect has been enhanced by anthropogenic emissions of green-house gases. Increased concentrations of carbon dioxide, methane, and nitrous oxide, CFCs, HFCs, PFCs, SF 6 , NF 3 , and other photochemically important gases caused by human activities such as fossil fuel consumption, trap more infra-red radiation, thereby exerting a warming influence on the climate. See greenhouse gas, anthropogenic, greenhouse effect, climate.(Source: US Environmental Protection Agency, 1999a)

ENSO - El Nino-Southern Oscillation. (Source: National Weather Service, 1999a.)

enteric fermentation - A digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal.(Source: US Environmental Protection Agency, 1999a)

Enthalpy - A thermodynamic property of a substance, defined as the sum of its internal energy plus the pressure of the substance times its volume, divided by the mechanical equivalent of heat. The total heat content of air; the sum of the enthalpies of dry air and water vapor, per unit weight of dry air; measured in Btu per pound (or calories per kilogram). (Source: US Department of Energy, 1999a).

Entropy - A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form. (Source: US Department of Energy, 1999a).

environment - The sum of all external conditions affecting the life, development, and survival of an organism. (Source: Carbon Dioxide Information Analysis Center, 1990a).

epidemiology - The study of diseases as they affect populations, including the distribution of disease or other health-related states and events in human populations, the factors (e.g., age, sex, occupation, and economic status) that influence this distribution, and the application of this study to control health problems. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Equinox - The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and September 23 (fall equinox). (Source: US Department of Energy, 1999a).

Erg - A unit of work done by the force of one dyne acting through a distance of one centimeter. (Source: US Department of Energy, 1999a).

ESCO - Efficiency Service Company. A company that offers to reduce a client's electricity consumption with the cost savings being split with the client. (Source: California Energy Commission, 1999a.)

estuary - Regions of interaction between rivers and near-shore ocean waters, where tidal action and river flow create a mixing of fresh and salt water. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Ethanol. Ethyl alcohol (C2H5OH) - A colorless liquid that is the product of fermentation used in alcoholic beverages, industrial processes, and as a fuel additive. Also known as grain alcohol. (Source: US Department of Energy, 1999a).

Ethyl Tertiary Butyl Ether (ETBE) - A chemical compound produced in a reaction between ethanol and isobutylene (a petroleum-derived by-product of the refining process). ETBE has characteristics superior to other ethers: low volatility, low water solubility, high octane value, and a large reduction in carbon monoxide and hydrocarbon emissions. (Source: US Department of Energy, 1999a).

euphotic zone - The layer of a body of water that receives sufficient sunlight for photosynthesis. The depth of this layer, which is about 80 m, is determined by the water's extinction coefficient, the cloudiness, and the sunlight's angle of incidence. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Eutectic - A mixture of substances that has a melting point lower than that of any mixture of the same substances in other proportions. (Source: US Department of Energy, 1999a).

Eutectic Salts - Salt mixtures with potential applications as solar thermal energy storage materials. (Source: US Department of Energy, 1999a).

EV (electric vehicle) - a vehicle powered by electricity, usually provided by batteries but may also be provided by photovoltaic (solar) cells or a fuel cell.

Evacuated Tube Collector - A solar collector in which the absorber is contained in a sealed glass tube, thereby providing for relatively high temperature heat gain. (Source: US Department of Energy, 1999a).

Evaporation - The conversion of a liquid to a vapor (gas), usually by means of heat. (Source: US Department of Energy, 1999a).

Evaporative Cooling - The physical process by which a liquid or solid is transformed into the gaseous state. For this process a mechanical device uses the outside air's heat to evaporate water that is held by pads inside the cooler. The heat is drawn out of the air through this process and the cooled air is blown into the home by the cooler's fan. (Source: US Department of Energy, 1999a).

Evaporator Coil - The inner coil in a heat pump that, during the cooling mode, absorbs heat from the inside air and boils the liquid refrigerant to a vapor, which cools the house. (Source: US Department of Energy, 1999a).

evapotranspiration - Discharge of water from the Earth's surface to the atmosphere by evaporation from bodies of water, or other surfaces, and by transpiration from plants. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Excitation - The power required to energize the magnetic field of a generator. (Source: US Department of Energy, 1999a).

Exempt Wholesale Generator - An unregulated subsidiary of an electric utility that is allowed to generate and sell wholesale power as an independent energy producer, and is exempt from the Public Utility Holding Company Act of 1935. (Source: US Department of Energy, 1999a).

exfiltration - Air flow outward through a wall, building envelope, etc. (Source: California Energy Commission, 1999a.)

Exothermic - A reaction or process that produces heat; a combustion reaction. (Source: US Department of Energy, 1999a).

Expanded Polystyrene - A type of insulation that is molded or expanded to produce coarse, closed cells containing air. The rigid cellular structure provides thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. Often used to insulate the interior of masonry basement walls. (Source: US Department of Energy, 1999a).

Expansion Tank - A tank used in a closed-loop solar heating system that provides space for the expansion of the heat transfer fluid in the pressurized collector loop. (Source: US Department of Energy, 1999a).

Expansion Valve - The device that reduces the pressure of liquid refrigerant thereby cooling it before it enters the evaporator coil in a heat pump. (Source: US Department of Energy, 1999a).

exponential growth - Growth in which some quantity, such as population size, increases by a constant percentage of the whole during each year or other time period; when the increase in quantity over time is plotted, this type of growth yields a curve shaped like the letter J.(Source: US Environmental Protection Agency, 1999a)

External Combustion Engine - An engine in which fuel is burned (or heat is applied) to the outside of a cylinder; a Stirling engine. (Source: US Department of Energy, 1999a).

Externality - The environmental, social, and economic impacts of producing a good or service that are not directly reflected in the market price of the good or service. (Source: US Department of Energy, 1999a).

Extruded Polystyrene - A type of insulation material with fine, closed cells, containing a mixture of air and refrigerant gas. This insulation has a high R-value, good moisture resistance, and high structural strength compared to other rigid insulation materials. (Source: US Department of Energy, 1999a).


F

Fahrenheit - A temperature scale in which the boiling point of water is 212 degrees and its freezing point is 32 degrees. To convert Fahrenheit to Celsius, subtract 32, multiply by 5, and divide the product by 9. For example: 100 degrees Fahrenheit - 32 = 68; 68 x 5 = 340; 340 / 9 = 37.77 degrees Celsius. (Source: California Energy Commission, 1999a.)

Fan - A device that moves and/or circulates air and provides ventilation for a room or a building. (Source: US Department of Energy, 1999a).

Fan Coil - A heat exchanger coil in which a fluid such as water is circulated and a fan blows air over the coil to distribute heat or cool air to the different rooms. (Source: US Department of Energy, 1999a).

Fan Velocity Pressure - The pressure corresponding to the outlet velocity of a fan; the kinetic energy per unit volume of flowing air. (Source: US Department of Energy, 1999a).

Federal Energy Management Program (FEMP) - A program of the U.S. Department of Energy (DOE) that implements energy legislation and presidential directives. FEMP provides project financing, technical guidance and assistance, coordination and reporting, and new initiatives for the federal government. It also helps federal agencies identify the best technologies and technology demonstrations for their use. (Source: US Department of Energy, 1999a).

Federal Energy Regulatory Commission (FERC) - This is an independent regulatory agency within the U.S. DOE that has jurisdiction over interstate electricity sales, wholesale electric rates, natural gas pricing, oil pipeline rates, and gas pipeline certification. It also licenses and inspects private, municipal, and state hydroelectric projects and oversees related environmental matters. (Source: US Department of Energy, 1999a).

feedback mechanisms - A sequence of interactions in which the final interaction influences the original one. Also see positive feedback and negative feedback. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Feeder - A power line for supplying electricity within a specified area. (Source: US Department of Energy, 1999a).

feedlot - Confined outdoor or indoor space used to raise hundreds to thousands of domesticated livestock. See rangeland.(Source: US Environmental Protection Agency, 1999a)

Feedstock - A raw material that can be converted to one or more products. (Source: US Department of Energy, 1999a).

Fenestration - The arrangement, proportion, and design of windows in a building. (Source: US Department of Energy, 1999a).

Fermentation - The decomposition of organic material to alcohol, methane, etc., by organisms, such as yeast or bacteria, usually in the absence of oxygen. (Source: US Department of Energy, 1999a).

fertilization, carbon dioxide - An expression (sometimes reduced to "fertilization") used to denote increased plant growth due to a higher car-bon dioxide concentration.(Source: US Environmental Protection Agency, 1999a)

fertilizer - Substance that adds inorganic or organic plant nutrients to soil and improves its ability to grow crops, trees, or other vegetation. See organic fertilizer.(Source: US Environmental Protection Agency, 1999a)

Fiberglass Insulation - Fiberglass is the most familiar type of insulation. It is spun from molten glass, and is pure white in its virgin state. Additives and binders often color the fiberglass, with pink and yellow being the most common. Fiberglass comes in rolls, batts and as loose insulation which is blown into place. (Source: Lawrence Berkeley Laboratory, 1999)

Filament - A coil of tungsten wire suspended in a vacuum or inert gas-filled bulb. When heated by electricity the tungsten "filament" glows. (Source: US Department of Energy, 1999a).

Filter (air) - A device that removes contaminants, by mechanical filtration, from the fresh air stream before the air enters the living space. Filters can be installed as part of a heating/cooling system through which air flows for the purpose of removing particulates before or after the air enters the mechanical components. (Source: US Department of Energy, 1999a).

financial mechanism - As defined by the UN Framework Convention on Climate Change, its role is to transfer funds and technologies to developing countries on a grant or concessional basis, under the guidance of the Convention's Conference of the Parties. The Global Environment Facility is "operating" the mechanism on an interim basis. (Source: UN Climate Change Secretariat, 1999a)

firm energy - Power supplies that are guaranteed to be delivered under terms defined by contract. (Source: California Energy Commission, 1999a.)

Fin - A thin sheet of material (metal) of a heat exchanger that conducts heat to a fluid. (Source: US Department of Energy, 1999a).

Finish - Both a noun and a verb to describe the exterior surface of building elements (walls, floors, ceilings, etc.) and furniture, and the process of applying it. (Source: US Department of Energy, 1999a).

Fire Classification - Classifications of fires developed by the National Fire Protection Association. (Source: US Department of Energy, 1999a).

Fireplace - A wood or gas burning appliance that is primarily used to provide ambiance to a room. Conventional, masonry fireplaces without energy saving features, often take more heat from a space than they put into it. (Source: US Department of Energy, 1999a).

Fireplace Insert - A wood or gas burning heating appliance that fits into the opening or protrudes on to the hearth of a conventional fireplace. (Source: US Department of Energy, 1999a).

Fire-Rating - The ability of a building construction assembly (partition, wall, floor, etc.) to resist the passage of fire. The rating is expressed in hours. (Source: US Department of Energy, 1999a).

Firewall - A wall to prevent the spread of fire; usually made of non-combustible material. (Source: US Department of Energy, 1999a).

Firing Rate - The amount of BTUs/hour or kWs produced by a heating system from the burning of a fuel. (Source: US Department of Energy, 1999a).

Firn - Material that is transitional between snow and glacier ice. It is formed from snow after passing through one summer melt season and becomes glacier ice after its permeability to liquid water falls to zero.

First-hour rating (water heater terminology) - The ability of a water heater to meet peak-hour demands. It measures how much hot water the heater will deliver during a busy hour. The first-hour rating accounts for the effects of tank size, and how quickly cold water is heated. (Source: Lawrence Berkeley Laboratory, 1999)

First Law of Thermodynamics - States that energy cannot be created or destroyed, but only changed from one form to another. First Law efficiency measures the fraction of energy supplied to a device or process that it delivers in its output. Also called the law of conservation of energy. (Source: US Department of Energy, 1999a).

Fiscal Year (FY) - The U.S. Government's 12-month financial year, from October to September, of the following calender year; e.g.: FY 1998 extends from Oct. 1, 1997 to Sept. 30, 1988. (Source: US Department of Energy, 1999a).

fission - A release of energy caused by the splitting of an atom's nucleus. This is the energy process used in conventional nuclear power plants to make the heat needed to run steam electric turbines. (Source: California Energy Commission, 1999a.)

fissionable material - A substance whose atoms can be split by slow neutrons. Uranium-235, plutonium-239 and uranium-233 are fissionable materials. (Source: California Energy Commission, 1999a.)

Fixture (lighting terminology) - The physical item refered to as a "lamp," i.e., "table lamp" or "floor lamp," is called the fixture by the lighting industry. (Source: Lawrence Berkeley Laboratory, 1999)

Flame Spread Classification - A measure of the surface burning characteristics of a material. (Source: US Department of Energy, 1999a).

Flame Spread Rating - A measure of the relative flame spread, and smoke development, from a material being tested. The flame spread rating is a single number comparing the flame spread of a material with red oak, arbitrarily given the number 100 and asbestos cement board with a flame spread of 0. Building codes require a maximum flame spread of 25 for insulation installed in exposed locations. (Source: US Department of Energy, 1999a).

flaring - The burning of waste gases through a flare stack or other device before releasing them to the air. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Flashing - Metal, usually galvanized sheet metal, used to provide protection against infiltration of precipitation into a roof or exterior wall; usually placed around roof penetrations such as chimneys. (Source: US Department of Energy, 1999a).

Flat-Black Paint - Nonglossy paint with a relatively high absorptance. (Source: US Department of Energy, 1999a).

Flat-Plate Solar Thermal/Heating Collectors - Large, flat boxes with glass covers and dark-colored metal plates inside that absorb and transfer solar energy to a heat transfer fluid. (Source: US Department of Energy, 1999a).

Flat-Plate Solar Photovoltaic Module - An arrangement of photovoltaic cells or material mounted on a rigid flat surface with the cells exposed freely to incoming sunlight. (Source: US Department of Energy, 1999a).

Flat Roof - A slightly sloped roof, usually with a tar and gravel cover. Most commercial buildings use this kind of roof. (Source: US Department of Energy, 1999a).

flexible fuel vehicle (FFV) - a vehicle that can operate on either alcohol fuels (methanol or ethanol) or regular unleaded gasoline or any combination of the two from the same tank. (Source: California Energy Commission, 1999a.)

Floor - The upward facing structure of a building. (Source: US Department of Energy, 1999a).

Floor Space - The interior area of a building, calculated in square feet or meters. (Source: US Department of Energy, 1999a).

Flow Condition - In reference to solar thermal collectors, the condition where the heat transfer fluid is flowing through the collector loop under normal operating conditions. (Source: US Department of Energy, 1999a).

Flow Restrictor - A water and energy conserving device that limits the amount of water that a faucet or shower head can deliver. (Source: US Department of Energy, 1999a).

Flue - The structure (in a residential heating appliance, industrial furnace, or power plant) into which combustion gases flow and are contained until they are emitted to the atmosphere. (Source: US Department of Energy, 1999a).

Flue Gas - The gas resulting from the combustion of a fuel that is emitted to the flue. (Source: US Department of Energy, 1999a).

Fluffing - The practice of installing blow-in, loose-fill insulation at a lower density than is recommended to meet a specified R-Value. (Source: US Department of Energy, 1999a).

Fluidized Bed Combustion (FBC) - A type of furnace or reactor in which fuel particles are combusted while suspended in a stream of hot gas. (Source: US Department of Energy, 1999a).

Fluorescent Light - The conversion of electric power to visible light by using an electric charge to excite gaseous atoms in a glass tube. These atoms emit ultraviolet radiation that is absorbed by a phosphor coating on the walls of the lamp tube. The phosphor coating produces visible light. (Source: US Department of Energy, 1999a).

fluorocarbons - Carbon-fluorine compounds that often contain other ele-ments such as hydrogen, chlorine, or bromine. Common fluorocarbons include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). See chlorofluorocar-bons, hydrochlorofluorocarbons, hydrofluorocarbons, per-fluorocarbons.(Source: US Environmental Protection Agency, 1999a)

Fly Ash - The fine particulate matter entrained in the flue gases of a combustion power plant. (Source: US Department of Energy, 1999a).

Flywheel Effect - The damping of interior temperature fluctuations by massive construction. (Source: US Department of Energy, 1999a).

Foam (Insulation) - A high R-value insulation product usually made from urethane that can be injected into wall cavities, or sprayed onto roofs or floors, where it expands and sets quickly. (Source: US Department of Energy, 1999a).

Foam Board - A plastic foam insulation product, pressed or extruded into board-like forms, used as sheathing and insulation for interior basement or crawl space walls or beneath a basement slab; can also be used for exterior applications inside or outside foundations, crawl spaces, and slab-on-grade foundation walls. (Source: US Department of Energy, 1999a).

Foam Core Panels - A type of structural, insulated product with foam insulation contained between two facings of drywall, or structural wood composition boards such as plywood, waferboard, and oriented strand board. (Source: US Department of Energy, 1999a).

fog - Liquid particles less than 40 microns in diameter that are formed by condensation of vapor in air. (Source: Carbon Dioxide Information Analysis Center, 1990a).

food chain - A sequence of organisms, each of which uses the next lower member of the sequence as a food source. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Foot Candle - A unit of illuminance; equal to one lumen per square foot. (Source: US Department of Energy, 1999a).

Foot Pound - The amount of work done in raising one pound one foot. (Source: US Department of Energy, 1999a).

Force - The push or pull that alters the motion of a moving body or moves a stationary body; the unit of force is the dyne or poundal; force is equal to mass time velocity divided by time. (Source: US Department of Energy, 1999a).

Forced Air System or Furnace - A type of heating system in which heated air is blown by a fan through air channels or ducts to rooms. (Source: US Department of Energy, 1999a).

Forced Outage - The shutdown of a generating unit, transmission line or other facility, for emergency reasons or a condition in which the generating equipment is unavailable for load due to unanticipated breakdown. (Source: US Energy Information Administration, 1999b)

Forced Ventilation - A type of building ventilation system that uses fans or blowers to provide fresh air to rooms when the forces of air pressure and gravity are not enough to circulate air through a building. (Source: US Department of Energy, 1999a).

forcing mechanism& - A process that alters the energy balance of the climate system (i.e., changes the relative balance between incoming solar radiation and outgoing infrared radiation from Earth). Such mechanisms include changes in solar irradiance, volcanic eruptions, and enhancement of the natural greenhouse effect by emission of carbon dioxide. (Source: US Environmental Protection Agency, 1999a)

forest - Terrestrial ecosystem (biome) with enough average annu-al precipitation (at least 76 centimeters or 30 inches) to support growth of various species of trees and smaller forms of vegetation.(Source: US Environmental Protection Agency, 1999a)

Formaldehyde - A chemical used as a preservative and in bonding agents. It is found in household products such as plywood, furniture, carpets, and some types of foam insulation. It is also a by-product of combustion and is a strong-smelling, colorless gas that is an eye irritant and can cause sneezing, coughing, and other health problems. (Source: US Department of Energy, 1999a).

fossil fuel - Any hydrocarbon deposit that can be burned for heat or power, such as petroleum, coal, and natural gas. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Foundation - The supportive structure of a building. (Source: US Department of Energy, 1999a).

Fractional Horse Power Motor - An electric motor rated at less than one horse power (hp). (Source: US Department of Energy, 1999a).

Frame (Window) - The outer casing of a window that sits in a designated opening of a structure and holds the window panes in place. (Source: US Department of Energy, 1999a).

Framing - The structural materials and elements used to construct a wall. (Source: US Department of Energy, 1999a).

framing effects - The effect of framing (wood or metal studs, joists, beams, etc.) on the overall U-value of a wall, roof, floor, window or other building surface. Framing generally increases the U-Value and decreases the R-Value of insulated surfaces. (Source: California Energy Commission, 1999a.)

framing percentage - The area of actual framing in an envelope assembly divided by the overall area of the envelope assembly. This percentage is used to calculate the overall U-value of an assembly. (Source: California Energy Commission, 1999a.)

Frequency - The number of cycles through which an alternating current passes per second; in the U.S. the standard for electricity generation is 60 cycles per second (60 Hertz). (Source: US Department of Energy, 1999a).

Freon - A registered trademark for a cholorfluorocarbon (CFC) gas that is highly stable and that has been historically used as a refrigerant. (Source: US Department of Energy, 1999a).

Fresnel Lens - An optical device for concentrating light that is made of concentric rings that are faced at different angles so that light falling on any ring is focused to the same point. (Source: US Department of Energy, 1999a).

Friction Head - The energy lost from the movement of a fluid in a conduit (pipe) due to the disturbances created by the contact of the moving fluid with the surfaces of the conduit, or the additional pressure that a pump must provide to overcome the resistance to fluid flow created by or in a conduit. (Source: US Department of Energy, 1999a).

Fuel - Any material that can be burned to make energy. (Source: US Department of Energy, 1999a).

Fuel Cell - An electrochemical device that converts chemical energy directly into electricity. (Source: US Department of Energy, 1999a).

Fuel cycle - The entire set of sequential processes or stages involved in the utilization of fuel, including extraction, transformation, transportation, and combustion. Emissions generally occur at each stage of the fuel cycle. (Source: US Energy Information Administration, 1999a).

Fuel Efficiency - The ratio of heat produced by a fuel for doing work to the available heat in the fuel. (Source: US Department of Energy, 1999a).

Fuel Grade Alcohol - Usually refers to ethanol to 160 to 200 proof. (Source: US Department of Energy, 1999a).

Fuel Oil - Any liquid petroleum product burned for the generation of heat in a furnace or firebox, or for the generation of power in an engine. Domestic (residential) heating fuels are classed as Nos. 1, 2, 3; Industrial fuels as Nos. 4, 5, and 6. (Source: US Department of Energy, 1999a).

Fuel Rate - The amount of fuel necessary to generate one kilowatt-hour of electricity. (Source: US Department of Energy, 1999a).

Fuelwood - Wood and wood products, possibly including coppices, scrubs, branches, etc., bought or gathered, and used by direct combustion. (Source: US Energy Information Administration, 1997a.)

fugitive emissions - Unintended gas leaks from the processing, transmission, and/or transportation of fossil fuels, CFCs from refrigera-tion leaks, SF 6 from electrical power distributor, etc.(Source: US Environmental Protection Agency, 1999a)

Full Sun - The amount of power density in sunlight received at the earth's surface at noon on a clear day (about 1,000 Watts/square meter). (Source: US Department of Energy, 1999a).

fungi - Molds, mildews, yeasts, mushrooms, and puffballs, a group of organisms that lack chlorophyll and therefore are not photosynthetic. They are usually nonmobile, filamentous, and multicellular. (Source: Carbon Dioxide Information Analysis Center, 1990a).

Furnace (Residential) - A combustion heating appliance in which heat is captured from the burning of a fuel for distribution, comprised mainly of a combustion chamber and heat exchanger. (Source: US Department of Energy, 1999a).

Fuse - A safety device consisting of a short length of relatively fine wire, mounted in a holder or contained in a cartridge and connected as part of an electrical circuit. If the circuit source current exceeds a predetermined value, the fuse wire melts (i.e. the fuse 'blows') breaking the circuit and preventing damage to the circuit protected by the fuse. (Source: US Department of Energy, 1999a).