## E

##### EARTH KILN

(heat). A relatively inefficient KILN made by mounding earth over the materials to be burned. Used in traditional CHARCOAL production.

F - meule a charbon de bois
S - horno de tierra
##### ECCENTRIC WHEEL

(gen). A wheel in which the axle is not at the center point, but slightly off-center.

F - roue excentrique
S - rueda excentrica
##### ECONOMIZER

(heat). A HEAT EXCHANGER that recovers heat from FLUE gases and uses it to heat feedwater or combustion air.

F - economiseur
##### EFFECTIVENESS

(heat) (meas). The ratio of actual heat transfer in a HEAT EXCHANGER to the maximum possible heat transfer.

F - efficacite
S - eficacia
##### EFFICIENCY

(gen). The ratio of the ENERGY output to the energy input. Efficiency is usually expressed as a percentage.

F - rendement
S - eficiencia
##### EFFLUENT

(biocon). [1] SLURRY that has been removed from a BIOGAS PLANT. [2] Liquid sewage after having passed through any stage in its purification.

F - effluent
S - efluente
##### EMISSIVITY

(sol). The ratio of RADIANT ENERGY emitted by a body to that emitted by a perfect BLACKBODY. A perfect blackbody has an emissivity of one; a perfect REFLECTOR, an emissivity of zero.

F - emissivite
##### EMITTANCE

(sol) (meas). A rating of the ability of a material to give off heat as RADIANT ENERGY.

F - emittance
S - emitancia
##### ENERGY

(gen). The capacity of a body to do work; POWER in action.

F - energie
S - energia
##### ENERGY CAPABILITY OF AN ELECTRICITY-PRODUCING DEVICE

(gen) (meas). The maximum amount of electricity that an electricity-producing device may produce under the best conditions during a given period. ENERGY capability is determined by the mechanical EFFICIENCY of the device.

F - capacite energetique d'un dispositif produisant du courant
##### ENERGY CONSERVATION

(gen). Practices and measures that increase the EFFICIENCY with which ENERGY is used or produced.

F - conservation de l'energie
S - conservacion de energia
##### ENERGY CONSUMPTION

(gen). The amount of ENERGY consumed in the form in which it is obtained by the user. This term excludes electrical generation and distribution losses. It also is called net energy consumption.

F - consommation d'energie
S - consumo de energia
##### ENERGY CONVERSION

(gen). The act of changing ENERGY from one form to another (e.g., WIND ENERGY to mechanical energy).

Mechanical -> Electrical
Wind Generator 40%
Water Turbine 68-93%
Steam Power Plant 40%
Mechanical -> Mechanical
Windmill 20-30%
Waterwheel 70-85%
Solar -> Thermal
Flat Collector 40-60%
Concentrator 80-90%
Chemical -> Thermal
Wood Combustion Burner 85% maximum
Chemical -> Electrical
Battery 80%

(Storage)

Chemical -> Chemical
Biogas Digester 40-60%
F - conversion de l'energie
S - conversion de energia
##### ENERGY PATTERN FACTOR

(wind). The ratio of the available ENERGY in all of the winds in a particular location over a certain period of time to the energy that would be available if the WIND SPEED over that period of time were constant at the mean wind speed over that period of time.

F - coefficient de diagramme energetique
S - factor energetico del viento
##### ENERGY PRODUCTS

(gen). Fuels that can be used to generate ENERGY. Also, the by-products that result when fuels are produced.

F - combustibles energetiques
S - productos energeticos
##### ENERGY STORAGE

(gen) (meas). The ability to convert ENERGY into other forms, such as heat or a chemical reaction, so that it can be retrieved for later use. Also the development, design, construction, and operation of devices for storing energy until needed. The technology includes devices such as batteries, pumped storage for hydroelectric generation and compressed gas.

F - stockage de l'energie
S - almacenamiento de energia
RENEWABLE ENERGY STORAGE
 Storage Medium Storage Efficiency (%) Major Loss Characteristics Cost* Complexity** SOLAR (Heat) Water 75-90 Leaks (thermal & physical) 2 1 Earth varies Leaks (thermal) 1 1 Rock 60-80 Leaks (thermal) 2 2 Salt Hydrates 75-95 Material Breakdown 3 3 WIND/WATER (Mechanical) Pumped Water 50-70 Evaporation, Friction 1 2 Compressed Air 40-50 Leaks, Friction 2 2 WIND/WATER (Electrical) Battery 70-85 Internal Discharge 3 3 METHANE Tank Leaks 1 2 Tank (compressed) 50-60 3 3 ALCOHOL Tank Leaks, Evaporation 1 1 * Relative Cost 1 = Negligible 2 = Intermediate ** Degree of Mechanical Complexity 3 = Considerable
##### ENHANCEMENT

(sol). Increasing the amount of sunlight transmitted through the GLAZING in a SOLAR COLLECTOR through the use of a REFLECTOR.

F - renforcement
S - intensificacion
##### ENZYMATIC HYDROLYSIS

(alc). The use of ENZYMES to convert STARCH into simple sugars. This is a stage in the production of ETHANOL.

F - saccharification enzymatique
S - hidrolisis enzimica
##### ENZYMES

(chem) (alc). Organic substances that are produced in the cells of living organisms, and which cause specific chemical changes. Enzymes are produced by BACTERIA or FUNGI and are used in the liquefication and SACCHARIFICATION steps of ALCOHOL production.

F - enzymes
S - enzimas
##### EOLIAN

(wind). Of, relating to, formed by, or deposited by the wind or air currents. (Syn: Aeolian)

F - eolien, eolienne
S - eolico
##### EQUINOX

(sol). Either of two times of year when the sun passes over the celestial equator and when the length of day and night are almost equal.

F - equinoxe
S - equinoccio
##### ETHANOL

(alc). A Flammable organic compound (C[H.sub.3]C[H.sub.2]OH) formed during sugar FERMENTATION. It is also called ethyl alcohol, GRAIN ALCOHOL, or simply ALCOHOL.

F - ethanol
S - etanol
##### ETHYL ALCOHOL

(alc). (See: ETHANOL)

F - alcool ethylique
S - alcohol etilico
##### EUTECTIC SALTS

(heat). Heat storing salts that melt at a relatively low temperature. They absorb large quantities of heat when they do melt. Heat is released when the salts freeze.

F - eutectiques
S - sales eutecticos
##### EVACUATED TUBE COLLECTOR

(sol). A SOLAR COLLECTOR that uses a vacuum to insulate the ABSORBER PLATE. This COLLECTOR is highly EFFICIENT but very expensive.

F - capteur a tube vide
S - colector con tubo vaciado
##### EVAPORATIVE COOLING

(refrig). The exchange of heat from air to a water spray or wet surface through a reversible THERMODYNAMIC process. Air passing through the water is cooled as the water evaporates. The process can be reversed by condensing the vapor on a cool surface.

F - refroidissement par evaporation
S - enfriamiento evaporante
##### EXCESS AIR

(heat). Air that passes through a COMBUSTION ZONE in excess of the quantity theoretically required for complete combustion.

F - exces d'air
S - aire excesivo

(sol) (meas). The amount of SOLAR RADIATION that would strike a surface if that surface were outside the Earth's atmosphere. (See also: CLEARNESS INDEX)

F - rayonnement solaire extraterrestre

## F

##### F

(meas). Abbreviation for FAHRENHEIT.

F - F
S - F
##### FAHRENHEIT

(meas). The temperature scale in which water freezes at 32 oF and boils at 212 oF. Temperatures of the Fahrenheit scale can be converted to equivalent temperatures on the CELSIUS or Centigrade scale by first subtracting 32 degrees from the Fahrenheit temperature, then multiplying the result by 5/9 according to the formula: ${\displaystyle (F-32)*5/9=C}$.

F - Fahrenheit
S - Fahrenheit
##### FALL WIND

(wind). A strong, cold, downhill wind.

F - vent catabatique
S - racha de viento
##### FANTAIL

(wind) (arc). A small, secondary ROTOR set at a right angle to the main ROTOR of a WINDMILL to provide the motive POWER to turn the CAP to face the wind.

F - gouvernail
S - timon
##### FARM WINDMILL

(wind). A multi-BLADED WINDMILL that is based on an Early American design and is used primarily for water pumping.

F - eolienne de ferme
S - molino de viento rural
##### FEATHER

(wind). Turning the SAILS or the ROTOR of a WIND MACHINE out of the wind to protect the device from damage from high WIND VELOCITIES.

F - mettre en drapeau
S - poner en bandolera
##### FEATHERING MECHANISM

(wind) (impl). A mechanism on a WINDMILL that automatically turns the BLADES out of the wind when winds are too strong. This slows the windmill, protecting it from damage in high winds.

F - mecanisme de mise en drapeau
S - mecanismo de puesta en bandolera
##### FEED

(gen). See: FEEDSTOCK)

F - alimentation
S - alimento
##### FEEDSTOCK

(gen). The raw ORGANIC MATTER, such as grain, fruit, DUNG, or other BIOMASS, used as the INFLUENT in the FERMENTATION or DIGESTION processes.

F - charge d'alimentation
S - materia prima organica
##### FENESTRATION

(sol). An opening in a building that admits light and/or air.

F - fenestration
S - ventanaje
##### FERMENT

(biocon). A transformation or DECOMPOSITION of ORGANIC MATTER by the catalytic effect of ENZYMATIC action. To cause or undergo the action of FERMENTATION.

F - fermenter
S - fermentar
##### FERMENTABLE SUGAR

(alc). (See: MONOSACCHARIDE)

F - sucre fermentable
S - azucar fermentable
##### FERMENTATION

(alc) (chem). [1] A biological sequence of ENZYMATIC reactions that convert sugars to carbon dioxide and ALCOHOL in the absence of FREE OXYGEN. The term generally refers to metabolism in the absence of oxygen. [2] The process by which YEAST changes sugar to ALCOHOL in the absence of air. [3] The process of chemical change in ORGANIC MATTER brought about by living organisms.

F - fermentation
S - fermentacion
##### FERMENTATION PERIOD

(gen) (meas). The length of time required for a substance to FERMENT.

F - duree de fermentation
S - periodo de fermentacion
##### FERMENTATION TANK

(alc). The container in which FERMENTATION takes place in an ETHANOL production operation.

F - cuve de fermentation
S - tanque de fermentacion
##### FERMENTER

(gen). (See: FERMENTATION TANK)

F - fermenteur
##### FETCH AREA

(wind). The geographic area over which the wind passes shortly before reaching a WIND MACHINE. It is considered in the selection of a site for a wind-powered device.

F - portee du vent
S - extension expuesta
##### FIRE BACK

(constr). A metal plate set in a CHIMNEY to control the back DRAFT of flames.

F - contre-feu
S - respaldo refractario
##### FIREBOX

(gen). The area in a stove, oven, or PRODUCER GAS GENERATOR in which combustion occurs.

F - chambre de combustion
S - caja refractaria
##### FIRE BRICK

(constr). A type of brick with a high melting point that is used to line FLUES, CHIMNEYS, furnaces, and fireplaces.

F - brique refractaire
##### FIXED-DOME DIGESTER

(biocon). A BIOGAS DIGESTER in which the gasholder is an integral part of the digester, rather than a FLOATING GAS CAP. This type of digester is usually used to produce fertilizer. METHANE is considered a by-product.

F - digesteur a dome fixe
S - digestor de sombrerete fijo
##### FLAT BLACK PAINT

(sol). A nonglossy black paint with a relatively high ABSORPTANCE.

F - peinture noire mate
S - pintura negra uniforme
##### FLAT-PLATE SOLAR COLLECTOR

(sol). A device that uses an ABSORBER PLATE to COLLECT SOLAR RADIATION without assistance of devices to concentrate the sun's rays.

F - capteur solaire a panneau plan
S - colector solar de placa lisa
##### FLOAT

(hydr). The BUCKET of a WATER WHEEL.

F - aube
S - paleta [1]
##### FLOATING GAS CAP

(biocon). A lid over a BIOGAS DIGESTER that rises or falls with the production of METHANE.

F - cloche a gaz flottante
S - sombrerete movible
##### FLOW

(gen). The volume of a substance passing a point per unit time (e.g., meters per second, gallons per hour, etc.)

F - debit
S - flujo
##### FLOW DESIGN

(hydr) (meas). The FLOW rate at which a TURBINE is designed to operate.

F - debit nominal
S - diseno de flujo
##### FLUE

(const). A passageway in a CHIMNEY that vents gases produced during combustion. The flue opening can be regulated to control the DRAFT in the oven or stove, thus changing the rate of combustion.

F - carneau
S - conducto de humos
##### FLUE GAS DRYING

(heat). THERMAL drying using gases in a FLUE as the source of heat.

F - sechage au gaz de carneau
S - secado por gases del conducto
##### FLUID

(gen). Any substance that FLOWS, such as a liquid or gas. Fluids differ from solids in that they cannot resist changes in their shape when acted upon by a force.

F - fluide
S - fluido
##### FLUIDIZED BED GASSIFIER

(prod). A type of PRODUCER GAS GENERATOR in which air FLOWS upward through a bed of suitably-sized fuel particles fast enough to buoy the particles and give them an appearance of great agitation. The fuel particles generally are small. This type of combustion reduces the sulphur-dioxide emissions when coal is burned.

F - gazogene a lit fluidise
##### FLUME

(hydr). [1] A HEAD RACE in the form of a trough or CHANNEL that carries water to a WATER WHEEL. [2] A waterway, usually made of wood and often supported on a trestle, that conveys water to be used for POWER, transportation, etc.

F - [1] coursier; [2] canal d'amenee
S - canaleta
##### FLYWHEEL

(gen) (impl). A rotating element attached to the shaft of a machine to maintain uniform angular velocity and revolutions per minute.

F - volant
S - volante
##### FOCUSING COLLECTOR

(sol). A type of SOLAR COLLECTOR that focuses the sun's rays on a sinqle point.

F - capteur a concentration [2]
S - colector enfocante
##### FOLD-UP REFLECTOR

(sol). A portable type of folding mirror used in SOLAR COOKERS to reflect sunlight.

F - reflecteur pliant
S - reflector plegable
##### FOOT-POUND

(gen) (meas). The amount of ENERGY required to lift one pound of a substance one foot.

F - pied-livre
S - libra-pie
##### FORCED CONVECTION

(heat). The use of a pump or blower to control the FLOW of heat into a heated FLUID (e.g. circulating warm air in a room or dwelling with a pump or blower).

F - convection forcee
##### FOSSIL FUELS

(fos). Nonrenewable, naturally-occurring fuels from ORGANIC MATTER. These include coal, crude oil, and natural gas.

F - combustibles fossiles
S - combustibles fosiles
##### FRACTIONATING COLUMN

(alc). A vertical tube or column attached to an ALCOHOL STILL that is usually filled with packing or intersected with plates. An internal REFLUX results in a separation between the high and low boiling fractions inside the column. Those with the lowest boiling point DISTILL out. (See also: DISTILLATION COLUMN)

F - colonne de fractionnement
S - columna de fraccionar
##### FRANCIS TURBINE

(hydr). A WATER TURBINE that operates on a low or medium HEAD and is often installed in large HYDROELECTRIC plants. Water enters the turbine radially and leaves axially.

F - turbine de Francis
S - turbina Francis
##### FREE OXYGEN

(bio). Oxygen in the atmosphere, which can be extracted at no cost. Conversely, oxygen extracted at a cost would cause the substance from which the oxygen molecules were taken to DECOMPOSE.

F - oxygene libre
S - oxigeno libre
##### FRESNEL COLLECTOR

(sol). A type of SOLAR COLLECTOR consisting of a concentric series of rings with reflecting surfaces. These rings focus SOLAR RADIATION onto an ABSORBER PLATE.

F - capteur a lentille de Fresnel
S - colector Fresnel
##### FRESNEL LENS

(sol). A type of lens built up from a number of narrow concentric segments. It is used in SOLAR CONCENTRATORS.

F - lentille de Fresnel
S - lente de Fresnel
##### FRICTION

(gen). Surface resistance to relative motion, which slows down movement and causes heat.

F - frottement
S - friccion

(hydr). HEAD or ENERGY lost due to FRICTION created by the contact between a moving stream of water and the conduit through which it is moving. In pipes, the friction head is also caused by bends in the pipelines, changes in the pipe diameter, valves, and couplings.

F - perte frictionnelle
S - perdida de carga por rozamiento
##### FRUCTOSE]](alc)

(chem). A FERMENTABLE sugar commonly found in fruit. Fructose can be used as a FEEDSTOCK in ETHANOL production.

F - fructose
S - fructosa
##### FUEL EFFICIENCY

(heat) (meas). The ratio of heat produced by a fuel for doing work to the available heat of the fuel. Fuel EFFICIENCY is determined by the nonheat-forming materials in the fuel and the nonwork-producing heat that is developed by the fuel.

F - rendement du combustible
S - eficiencia del combustible
##### FUELWOOD

(heat). Any type of wood that can be used to fuel a fire.

F - bois de chauffe
S - lena
##### FULL SAIL

(wind) (arc). A COMMON SAIL with the cloth fully spread.

F - aile deployee
##### FUNGUS

(bio). One of numerous plants in the division of Thallophyta characterized by a lack of chlorophyll, including YEAST, molds, and mushrooms. Fungi do not require FREE OXYGEN to survive. (Plural: fungi)

F - champignon
S - hongo
##### FURLING

(wind). Rollinq up and tying back SAILS of a WINDMILL to keep the ROTOR from turning.

F - ferlage
S - aferramiento
##### FURLING SPEED

(wind). (See: CUT-OUT SPEED)

F - vitesse de ferlage

## G

##### GASAHOL

(alc). A gasoline substitute or supplement derived from 10 percent ETHANOL and 90 percent unleaded gasoline. (Syn: gasohol)

F - carburol
S - gasohol
##### GAS CAP

(biocon). (See: GASHOLDER)

F - cloche a gaz
S - tapa de gas
##### GAS DIGESTION

(biocon). The second stage of BIOGAS generation, during which METHANE ([CH.sub.4]) is produced.

F - digestion de gaz
S - digestion de gas
##### GASHOLDER

(biocon). (1) A container for holding the BIOGAS produced in a DIGESTER. The size of the holder depends on the rates of gas production and gas use. (See also: FLOATING GAS CAP)

F - gazometre
S - gasometro
##### GASIFICATION

(prod). The conversion of wood or coal to COMBUSTIBLE GAS without leaving a combustible residue.

F - gazeification
S - gasificacion
##### GASIFIER

(prod). A special type of furnace in which the air supply to the COMBUSTION ZONE is carefully metered. This promotes the production of COMBUSTIBLE GASES as wood or coal are burned.

F - gazogene
##### GAS PRODUCTION RATE

(biocon) (meas). The quantity of METHANE generated per unit of time. It generally is expressed as cubic feet/day or cubic meters/day. The figure should be quoted under standard conditions of temperature and pressure.

F - taux de production du gaz
S - tasa de produccion de gas
##### GAS SCRUBBER

(gen). (See: SCRUBBING)

F - epurateur de gaz
S - lavagases
##### GAS STORAGE CAPACITY

(biocon). The maximum amount of METHANE that a BIOGAS DIGESTER is able to store. The amount generally is expressed in cubic feet or cubic meters.

F - capacite de stockage de gaz
S - capacidad de almacenamiento de gas
##### GAS TURBINE

(auto). An ALTERNATIVE COMBUSTION ENGINE in which a gas, under pressure or formed by combustion, is directed against the BLADES of a TURBINE. The ENERGY in the expanding gas is thereby converted into useful mechanical energy.

F - turbine a gaz
S - turbina de gas
##### GEAR RATIO

(gen) (meas). The number of revolutions required of one gear to turn another gear, which generally is of a different size.

F - demultiplication
S - relacion de los engranajes
##### GENERATOR

(elec) (impl). A device that converts mechanical ENERGY into electrical energy.

F - generateur
##### GENGAS

(prod). (See: PRODUCER GAS)

F - gaz pauvre de gazogene
S - gengas
##### GEOPRESSURED RESERVOIR

(geo). A GEOTHERMAL RESERVOIR consisting of porous sands that contain water or BRINE at high temperatures and pressure.

F - reservoir sous geopression
S - tanque de presion geotermica
##### GEOTHERMAL

(geo). Of or relating to the heat of the Earth's interior.

F - geothermique
S - geotermico
##### GEOTHERMAL FIELD

(geo). A geographical region with known GEOTHERMAL POWER sources that might be tapped to produce ENERGY.

F - zone geothermique
S - zona geotermica
##### GEOTHERMAL POWER

(geo). ENERGY obtained from GEOTHERMAL sources. Geothermal power is tapped in three ways: by using hot water, steam, or DRY STEAM. Each may be used to drive a TURBINE.

F - energie geothermique
S - energia geotermica
##### GEOTHERMAL RESERVOIR

(geo). A water reserve created near a HOT DRY ROCK RESERVOIR to develop a potential GEOTHERMAL POWER site.

F - reservoir geothermique
S - tanque geotermico
##### GEOTHERMAL STEAM

(geo). Steam drawn from sources within the Earth.

F - vapeur geothermique
S - vapor geotermico
##### GEYSER

(geo). Natural steam or hot water spouts in active GEOTHERMAL regions.

F - geyser
S - geiser
##### GIN POLE

(wind). A long board or pipe used to improve the leverage in lifting a TOWER for a WINDMILL.

F - fleche de levage
S - mastil grua
##### GLAZING

(impl) (sol). A transparent sheet that admits sunlight to a SOLAR COLLECTOR and then inhibits the escape of heat. Commonly used glazing materials include ACETATE, acrylic, fiber-reinforced plastics, and glass.

F - vitrification

F - rayonnement global
##### GLUCOSE

(chem) (alc). The most common sugar, which is derived from STARCH during the ETHANOL production process.

F - glucose
S - glucosa
##### GOBAR GAS

(biocon). (See: BIOGAS)

F - bio-gaz
S - gas gobar
##### GOVERNOR

(gen) (impl). A device that regulates the speed of an engine or other device under varying conditions of load and pressure. Also a device for regulating the FLOW or pressure of a FLUID passing through a device.

F - regulateur
##### GRAIN ALCOHOL

(alc). ETHANOL made from grain by DISTILLATION.

F - alcool de grains
S - alcohol de granos
##### GRAM CALORIE

(gen). The amount of ENERGY required to raise one gram of water one degree CELSIUS.

F - calorie [2]
S - caloria-gramo
##### GRAMLAXMI GAS

(biocon). (See: BIOGAS)

F - bio-gaz
S - gas gramlaxmi
##### GRATE

(impl) (heat). A frame of metal bars that holds fuel above the floor of a firebox. It usually is used in a boiler, GASIFIER, fireplace, or stove.

F - grille
S - parilla
##### GRAVITY CONVECTION]] heat).

(See: NATURAL CONVECTION)

F - convection par pesanteur
##### GUIDE VANES

(hydr) (impl). Surfaces that direct water to the appropriate parts of TURBINE BLADES or BUCKETS so as to increase POWER output.

F - aubes directrices
S - alabe director
##### GUSSET

(constr) (wind). A triangular metal brace for reinforcing a corner or angle. It is commonly used in TOWER construction.

F - gousset
S - esquinero
##### GUST

(wind). A sudden, brief increase in WIND VELOCITY that is then followed by calmer air.

F - rafale
S - rafaga
##### GUYED TOWER

(impl) (wind). A WINDMILL TOWER that is supported by GUY WIRES.

F - pylone haubanne