AIR-TO-AIR HEAT EXCHANGER - A device with separate air chambers that transfers heat between the conditioned air being exhausted and the outside air being supplied to a building.
ALCOHOL FUELS - Liquid chemicals made from renewable resources such as locally grown crops and even waste products. They contain a certain combination of hydrogen, carbon and oxygen that qualifies them as fuels. Methanol and ethanol are two types of alcohol fuels used in cars.
ALTERNATING CURRENT - (AC) Flow of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in Europe moves in current that shifts direction at a rate of 50 times per second (50 Hertz).
ALTERNATIVE ENERGY SOURCES - See RENEWABLE ENERGY.
AMBIENT AIR TEMPERATURE - Surrounding temperature, such as the outdoor air temperature around a building.
AMPERE (Amp) - The unit of measure that tells how much electricity flows through a conductor. It is like using litres per second to measure the flow of water. For example, a 2,000 watt, 230-Kettle dryer pulls 8.7 amperes of electric current (watts divided by volts). You would therefore have a 13 amp fuse on the kettle plug. See FUSES.
ANTHRACITE - Hard coal, found deep in the earth. It burns very hot, with little flame. It usually has a heating value of 32,500 –34,000 kJ/kg or approximately 9kWh per kg.
BARREL - In the petroleum industry, a barrel is 42 U.S. gallons or 149 litres.
BATTERY - A device that stores energy and produces electric current by chemical action.
BIODIESEL - Any liquid biofuel suitable as a diesel fuel substitute or diesel fuel additive or extender. Biodiesel fuels are typically made from oils such as soybeans, rapeseed, or sunflowers, or from animal tallow. Biodiesel can also be made from hydrocarbons derived from agricultural products such as rice hulls.
BIOMASS - Energy resources derived from organic matter. These include wood, agricultural waste and other living-cell material that can be burned to produce heat energy. They also include algae, sewage and other organic substances that may be used to make energy through chemical processes.
BIOFUELS - Liquid fuels and blending components produced from biomass (plant) feedstock, used primarily for transportation.
BITUMINOUS COAL - Soft coal containing large amounts of carbon. It has a luminous flame and produces a great deal of smoke.
BLACKOUT - A power loss affecting many electricity consumers over a large geographical area for a significant period of time.
BOILER - A closed vessel in which water is converted to pressurised steam.
BREEDER - A nuclear reactor that produces more fuel than it consumes. The breeder, invented in the United States, is used as a power source in several European countries.
BRITISH THERMAL UNIT (Btu) – A measure of heat energy. It takes one Btu to raise the temperature of one pound of water by one degree Fahrenheit at sea level. Boilers are often rates in BTUs.
BROWNOUT - A controlled power reduction in which the utility decreases the voltage on the power lines, so customers receive weaker electric current. Brownouts can be used if total power demand exceeds the maximum available supply. The typical household does not notice the difference.
BUILDING ENERGY RATING - As part of the Energy Performance of Buildings Directive, a Building Energy Rating (BER) certificate, which is effectively an energy label, will be required at the point of sale or rental of a building, or on completion of a new building. The BER will be accompanied by an "Advisory Report" setting out recommendations for cost-effective improvements to the energy performance of the building. However there will be no legal obligation on vendors or prospective purchasers to carry out the recommended improvements. SEE EPBD.
BUILDING ENVELOPE - The exterior assembly that encloses the interior space of a building. It serves as the outer shell to protect the indoor environment as well as to facilitate its climate control.
BUILDING MANAGEMENT SYSTEM (BMS) - A computer software program, usually configured in a hierarchical manner, to control, monitor and manage all the equipment installed in the building. This equipment can include heating, ventilation, cooling, security, and lighting.
BUILDING REGULATIONS - Regulations set out by the government to ensure that each house built in Ireland is to a minimum standard that has to be achieved. The regulations apply to the manufacture of products and service and the use of the product by the consumer.
Standards are set out to protect work environments and the quality of goods. Part L of the Regulations deal with “Conservation of Fuel and Energy”.
CALORIE - One energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories
CALORIE (energy calorie - small "c" - as opposed to food Calorie - capital "C") Any of several approximately equal values of heat, each measured as the quantity of heat require to raise the temperature of 1 gram of water by 1 degree Celsius from a standard initial temperature, esp. from 3.98 degrees Celsius. 14.5 degrees Celsius, or 19.5 degrees Celsius, at 1 atmosphere pressure. A calorie is the unit of heat equal to 4.184 joules.
CAPACITY - The amount of electric power for which a generating unit, generating station, or other electrical apparatus is rated either by the user or manufacturer. The term is also used for the total volume of natural gas that can flow through a pipeline over a given amount of time, considering such factors as compression and pipeline size.
CAULKING - Material used to make an air-tight seal by filling in cracks, such as those around windows and doors.
CARBON DIOXIDE - A colourless, odourless, non-poisonous gas that is a normal part of the air. Carbon dioxide, also called CO2, is exhaled by humans and animals and is absorbed by green growing things and by the sea.
CELSIUS - A temperature scale based on the freezing (0 degrees) and boiling (100 degrees) points of water. Abbreviated as C in second and subsequent references in text. Formerly known as Centigrade. To convert Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32. For example:
10 degrees Celsius x 9 = 90; 90 / 5 = 18; 18 + 32 = 50 degrees Fahrenheit.
CFL – SEE FLUORESCENT LAMP
CHEMICAL ENERGY - The energy generated when a chemical compound combusts, decomposes, or transforms to produce new compounds.
COAL - Black or brown rock, formed under pressure from organic fossils in prehistoric times, that is mined and burned to produce heat energy.
COAL CONVERSION - Changing coal into synthetic gas or liquid fuels.
COAL OIL - Oil that can be obtained by distilling bituminous coal.
COP (COEFFICIENT OF PERFORMANCE) - Used to rate the performance of a heat pump, the COP is the ratio of the rate of useful heat output delivered by the complete heat pump unit (exclusive of supplementary heating) to the corresponding rate of energy input, in consistent units and under specific conditions.
COMBINED HEAT AND POWER PLANT (CHP) OR COGENERATION - The use of a heat engine or a power station to simultaneously generate both electricity and useful heat. Conventional power plants emit the heat created as a by product of electricity generation into the environment through , as flue gas, or by other means. CHP captures the by product heat for domestic or industrial heating purposes, either very close to the plant, or - especially in Scandinavia and eastern Europe - for distribution through pipes to heat local housing (district heating).
COMBUSTION Burning - Rapid oxidation, with the release of energy in the form of heat and light
CONDENSATE - Liquid fuel obtained by burning gas or vapour produced from oil and gas wells.
CONDUCTION - The transfer of heat energy through a material (solid, liquid or gas) by the motion of adjacent atoms and molecules without gross displacement of the particles.
CONSERVATION - Measures taken to cause less energy to be used. These measures may involve improved efficiency, avoidance of waste, reduced consumption, etc. They may involve installing equipment (such as a computer to ensure efficient energy use), modifying equipment (such as making a boiler more efficient), adding insulation, changing behaviour patterns, etc.
CONVECTION - Transferring heat by moving air, or transferring heat by means of upward motion of particles of liquid or gas heat from beneath.
COOLING TOWER – Evaporative devices for cooling water by contact with air.
CORD – (US term) A measure of volume, 4 by 4 by 8 feet, used to define amounts of stacked wood available for use as fuel. Burned, a cord of wood produces about 5 million calories of energy.
CRUDE OIL - Petroleum as found in the earth, before it is refined into oil products. Also called CRUDE.
DAYLIGHTING -The use of sunlight to supplement or replace electric lighting.
DAYLIGHTING CONTROL - A control system that varies the light output of an electric lighting system in response to variations in available daylight.
DEEP MINING - Extraction of coal or minerals at depths greater than 1,000 feet. Coal usually is deep-mined at not more than 1,500 feet.
DEGREE DAY - A unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal annual heating load of a building. When the mean temperature is less than 18 degrees Celsius the heating degree days are equal to the total number of days that temperature is less than 18 degrees Celsius for an entire year.
DEMAND (Utility) - The level at which electricity or natural gas is delivered to users at a given point in time. Electric demand is expressed in kilowatts.
DEMAND BILLING - The electric capacity requirement for which a large user pays. It may be based on the customer's peak demand during the contract year, on a previous maximum or on an agreed minimum. Measured in kilowatts.
DEMAND CHARGE - The sum to be paid by a large electricity consumer for its peak usage level.
DIESEL - A specific fractional distillate of fuel oil (mostly petroleum) that is used as fuel in a diesel engine invented by German engineer Rudolf Diesel.
DIFFUSE RADIATION - Solar radiation, scattered by water vapour, dust and other particles as it passes through the atmosphere, so that it appears to come from the entire sky. Diffuse radiation is higher on hazy or overcast days than on clear days.
DIRECT CURRENT (DC) - Electricity that flows continuously in the same direction.
DIRECT RADIATION - Radiation that has travelled a straight path from the sun, as opposed to diffuse radiation.
DIRECT SOLAR GAIN - Solar energy collected from the sun (as heat) in a building through windows, walls, skylights, etc.
DISTRIBUTION SYSTEM (Electric utility) - The substations, transformers and lines that convey electricity from high-power transmission lines to ultimate consumers. See GRID.
DOUBLE GLAZING - Windows having two sheets of glass with an airspace between.
ECOLOGY - The study of interrelationships of organisms to one another and to their environment.
ELECTRICITY - A general term for the variety of phenomena resulting from the presence and flow of electric charge.
ELECTRIC GENERATOR - A device that converts a heat, chemical or mechanical energy into electricity.
ENERGY - The capacity for doing work. Forms of energy include: thermal, mechanical, electrical and chemical. Energy may be transformed from one form into another.
ENERGY CONSUMPTION - The amount of energy consumed in the form in which it is acquired by the user. The term excludes electrical generation and distribution losses.
ENERGY EFFICIENCY - Using less energy/electricity to perform the same function. "Energy conservation" is a term which has also been used but it has the connotation of doing without in order to save energy rather than using less energy to do the some thing and so is not used as much today. Many people use these terms interchangeably.
ENERGY PERFORMANCE OF BUILDINGS DIRECTIVE (EPBD) - The European Union Energy Performance of Buildings Directive was published in the Official Journal on the 4th January 2003.
The overall objective of the Directive is to:
“promote the improvement of energy performance of buildings within the Community taking into account outdoor climatic and local conditions, as well as indoor climate requirements and cost-effectiveness'
ETHANOL (also know as Ethyl Alcohol or Grain Alcohol, CH3CH2OH) - a liquid that is produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. Used as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at 10 percent concentration. Ethanol can also be used in higher concentration (E85) in vehicles optimised for its use.
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.
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.
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.
FLAT PLATE - A device used to collect solar energy. It is a piece of metal painted black on the side facing the sun, to absorb the sun's heat.
FLEXIBLE FUEL VEHICLE (FFV) - a vehicle that can operate on either alcohol fuels (methanol or ethanol) or regular unleaded petrol or any combination of the two from the same tank.
FLUE GAS - Gas that is left over after fuel is burned and which is disposed of through a pipe or stack to the outer air.
FLUORESCENT LAMP - A tubular electric lamp that is coated on its inner surface with a phosphor and that contains mercury vapour whose bombardment by electrons from the cathode provides ultraviolet light which causes the phosphor to emit visible light either of a selected colour or closely approximating daylight.
CFL's are simply miniature versions of full-sized fluorescents. The compact design allows them to be used in place of incandescent light bulbs.
FOSSIL FUEL - Oil, coal, natural gas or their by-products. Fuel that was formed in the earth in prehistoric times from remains of living-cell organisms.
FUEL CELL - A device or an electrochemical engine with no moving parts that converts the chemical energy of a fuel, such as hydrogen, and an oxidant, such as oxygen, directly into electricity. The principal components of a fuel cell are catalytically activated electrodes for the fuel (anode) and the oxidant (cathode) and an electrolyte to conduct ions between the two electrodes, thus producing electricity.
FUSION ENERGY - A power source, now under development, based on the release of energy that occurs when atoms are combined under the most extreme heat and pressure. It is the energy process of the sun and the stars.
GALLON - A unit of volume. A U.S. gallon has 231 cubic inches or 3.785 litres. A European gallon has 4.54 litres.
GAS - Gaseous fuel (usually natural gas) that is burned to produce heat energy.
GEOTHERMAL HEATING - A method of heating and cooling a building. It takes advantage of the natural stable warmth stored in the earth. Normally the earth temperature is around 12.8oC (or 55 °F) at depths of 10 ft. In climates warmer than 12.8oC (or 55 °F), this can be used to cool a building, and in colder climates (those under 12.8oC or 55oF) it can be used for warmth. This is accomplished by one of a number of methods. A heat pump uses the extracted water or transfer fluid (such as water mixed with antifreeze) as a heat source in winter and a heat sink in summer. Some heat pumps provide heating and cooling via forced air distribution, and others through the heating and/or chilling of water for radiant type systems. Some systems are used to heat domestic hot water.
Types of geothermal systems:
GIGAWATT (GW) - One thousand megawatts (1,000 MW) or, one million kilowatts (1,000,000 kW) or one billion watts (1,000,000,000 watts) of electricity.
GLOBAL CLIMATE CHANGE - Gradual changing of global climates due to build-up of carbon dioxide and other greenhouse gases in the earth's atmosphere. Carbon dioxide produced by burning fossil fuels has reached levels greater than what can be absorbed by green plants and the seas.
GREENHOUSE EFFECT - The presence of trace atmospheric gases make the earth warmer than would direct sunlight alone. These gases (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], tropospheric ozone [O3], and water vapour [H2O]) allow visible light and ultraviolet light (short-wave radiation) to pass through the atmosphere and heat the earth's surface. This heat is re-radiated from the earth in form of infrared energy (longwave radiation). The greenhouse gases absorb part of that energy before it escapes into space. This process of trapping the longwave radiation is known as the greenhouse effect. Scientists estimate that without the greenhouse effect, the earth's surface would be roughly 54 degrees Fahrenheit colder than it is today -- too cold to support life as we know it.
GRID - A system of interconnected power lines and generators that is managed so that the generators are dispatched as needed to meet the requirements of the customers connected to the grid at various points. Grid can also refer to the layout of a gas distribution system of a city or town in which pipes are laid in both directions in the streets and connected at intersections.
HEAT CAPACITY - The amount of heat necessary to raise the temperature of a given mass one degree. Heat capacity may be calculated by multiplying the mass by the specific heat.
HEAT GAIN - an increase in the amount of heat contained in a space, resulting from direct solar radiation, heat flow through walls, windows, and other building surfaces, and the heat given off by people, lights, equipment, and other sources.
HEAT LOSS - A decrease in the amount of heat contained in a space, resulting from heat flow through walls, windows, roof and other building surfaces and from exfiltration of warm air.
HEAT PUMP - An air-conditioning unit which is capable of heating by refrigeration, transferring heat from one (often cooler) medium to another (often warmer) medium, and which may or may not include a capability for cooling. This reverse-cycle air conditioner usually provides cooling in summer and heating in winter.
HEAT TRANSFER - Flow of heat energy induced by a temperature difference. Heat flow through a building envelope typically flows from a heated, or hot area to a cooled, or cold area.
HEATING DEGREE DAY - A unit that measure the space heating needs during a given period of time.
HEATING LOAD - The rate at which heat must be added to a space in order to maintain the desired temperature within the space.
HERTZ - A unit of electromagnetic wave frequency that is equal to one cycle per second. - It is named after Henrich R. Hertz.
HORSEPOWER (HP) - A unit for measuring the rate of doing work. One horsepower, approximately equals three quarters of a kilowatt (745.7 watts).
HYDROELECTRIC POWER - Electricity produced by falling water that turns a turbine generator. Also referred to as HYDRO.
HYBRID VEHICLE - Usually a hybrid EV, a vehicle that employs a combustion engine system together with an electric propulsion system. Hybrid technologies expand the usable range of EVs beyond what an all-electric-vehicle can achieve with batteries only.
INCANDESCENT LAMP - An electric lamp in which a filament is heated by an electric current until it emits visible light. Most of the energy goes into heat rather than light which makes this type of lamp extremely inefficient.
INFILTRATION - The uncontrolled inward leakage of air through cracks and gaps in the building envelope, especially around windows, doors and duct systems.
INSOLATION - The total amount of solar radiation (direct, diffuse, and reflected) striking a surface exposed to the sky.
INSULATION, THERMAL - A material having a relatively high resistance of heat flow and used principally to retard heat flow.
INTERNAL COMBUSTION ENGINE - An engine in which fuel is burned inside the engine. A car's petrol engine or rotary engine is an example of a internal combustion engine. It differs from engines having an external furnace, such as a steam engine
JOULE - A unit of work or energy equal to the amount of work done when the point of application of force of 1 newton is displaced 1 meter in the direction of the force. It takes 1,055 joules to equal a British thermal unit (BTU).
KEROSENE - Certain colourless, low-sulphur oil products that burn without producing much smoke
KILOWATT (kW) - One thousand (1,000) watts.
KILOWATT-HOUR (kWh) - The most commonly-used unit of measure telling the amount of electricity consumed over time. It means one kilowatt of electricity supplied for one hour.
LANDFILL GAS - Gas generated by the natural degrading and decomposition of municipal solid waste by anaerobic micro-organisms in sanitary landfills. The gases produced, carbon dioxide and methane, can be collected by a series of low-level pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity.
LPG (LIQUEFIED PETROLEUM GAS) - A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and as a transportation fuel. It is normally created as a by-product of petroleum refining and from natural gas production.
LOAD - An end-use device or an end-use customer that consumes power. Load should not be confused with demand, which is the measure of power that a load receives or requires.
LOSSES (Electric utility) - Electric energy or capacity that is wasted in the normal operation of a power system. Some kilowatt-hours are lost in the form of waste heat in electrical apparatus such as substation conductors. LINE LOSSES are kilowatts or kilowatt-hours lost in transmission and distribution lines under certain conditions.
LUMEN - A measure of the amount of light available from a light source equivalent to the light emitted by one candle.
LUMENS/WATT - A measure of the efficacy of a light fixture; the number of lumens output per watt of power consumed.
LUMINAIRE - A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.
LUX - A unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter.
MEGAWATT (MW) - One thousand kilowatts (1,000 kW) or one million (1,000,000) watts.
MEGAWATT HOUR (MWh) - One thousand kilowatt-hours.
METER - A device for measuring levels and volumes of a customers gas and electricity use.
METHANE - A light hydrocarbon that is the main component of natural gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gases. Chemical formula is CH4.
NATURAL GAS - Hydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gases.
NUCLEAR ENERGY - Power obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators.
OCCUPANCY SENSOR - A control device that senses the presence of a person in a given space, commonly used to control lighting systems in buildings.
OCTANE - A rating scale used to grade petrol as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons, C8H18. Normal octane is a colourless liquid found in petroleum boiling at 124.6 degrees Celsius.
OCTANE RATING - A measure of petrol’s resistance to exploding too early in the engine cycle, which causes knocking. The higher the rating, the lower the chance of premature ignition.
OHM - A unit of measure of electrical resistance. One volt can produce a current of one ampere through a resistance of one ohm.
OIL SHALE - A type of rock containing organic matter that produces large amounts of oil when heated to high temperatures.
OPEC - Acronym for Organisation of Petroleum Exporting Countries founded in 1960 for unify and co-ordinate petroleum polices of the members. Headquarters is in Vienna, Austria.
PASSIVE SOLAR ENERGY - Use of the sun to help meet a building¹s energy needs by means of architectural design (such as arrangement of windows) and materials (such as floors that store heat, or other thermal mass).
PASSIVE SOLAR SYSTEM - A solar heating or cooling system that uses no external mechanical power to move the collected solar heat.
PEAK LOAD - The highest electrical demand within a particular period of time. Daily electric peaks on weekdays occur in late afternoon and early evening.
PEAT - A heterogeneous mixture of partly decomposed organic matter that has accumulated in a water saturated environment over a very long period of time. Peat geologically is considered a very young form of coal and has a heating value of 6,600 Btu/pound in situ.
PETROCHEMICALS - Chemicals made from oil.
PHOTOVOLTAIC CELL - A semiconductor that converts light directly into electricity.
PIPELINE - A line of pipe with pumping machinery and apparatus (including valves, compressor units, metering stations, regulator stations, etc.) for conveying a liquid or gas.
PPM (PARTS PER MILLION) - The unit commonly used to represent the degree of pollutant concentration where the concentrations are small.
R-VALUE - A unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher a materials R-value number, the greater its insulating properties and the slower the heat flow through it. The specific value needed to insulate a home depends on climate, type of heating system and other factors.
RADIANT ENERGY - Energy transferred by the exchange of electromagnetic waves from a hot or warm object to one that is cold or cooler. Direct contact with the object is not necessary for the heat transfer to occur.
RADIATION - The flow of energy across open space via electromagnetic waves such as light. Passage of heat from one object to another without warming the air space in between.
REACTOR - A device in which a controlled nuclear chain reaction can be maintained, producing heat energy.
RECLAIMED OIL - Lubricating oil that is processed to be used over again.
RECOVERED ENERGY - Reused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.
REFINERY -- A facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporising the chemical components of crude oil that have different boiling points. These are distilled into usable products such as petrol, fuel oil, lubricants and kerosene.
REFRIGERANT - A fluid such as Freon that is used in cooling devices to absorb heat from surrounding air or liquids as it evaporates.
RENEWABLE ENERGY - Resources that are constantly renewed or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power and sea currents.
RENEWABLE RESOURCES - Renewable energy resources are naturally replenished but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stock-limited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can probably be replenished. Renewable energy resources include: biomass, hydro, geothermal, solar and wind. In the future they could also include the use of ocean thermal, wave, and tidal action technologies. Utility renewable resource applications include bulk electricity generation, on-site electricity generation, distributed electricity generation, non-grid-connected generation, and demand-reduction (energy efficiency) technologies.
RESISTANCE (ELECTRICAL) - The ability of all conductors of electricity to resist the flow of current, turning some of it into heat. Resistance depends on the cross section of the conductor (the smaller the cross section, the greater the resistance) and its temperature (the hotter the cross section, the greater its resistance).
SOLAR CELL - A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.
SOLAR COLLECTOR - A surface or device that absorbs solar heat and transfers it to a fluid. The heated fluid then is used to move the heat energy to where it will be useful, such as in water or space heating equipment.
SOLAR ENERGY - Heat and light radiated from the sun.
SOLAR HEATING AND HOT WATER SYSTEMS - Solar heating or hot water systems provide two basic functions: (a) capturing the sun's radiant energy, converting it into heat energy, and storing this heat in insulated storage tank(s); and (b) delivering the stored energy as needed to either the domestic hot water or heating system. These components are called the collection and delivery subsystems.
SOLAR IRRADIATION - The amount of radiation, both direct and diffuse, that can be received at any given location.
SOLAR POWER - Electricity generated from solar radiation.
SOLAR RADIATION - Electromagnetic radiation emitted by the sun.
SOLAR SATELLITE POWER - A proposed process of using satellites in geosynchronous orbit above the earth to capture solar energy with photovoltaic cells, convert it to microwave energy, beam the microwaves to earth where they would be received by large antennas, and changed from microwave into usable electricity.
STIRLING ENGINE - An external combustion engine that converts heat into useable mechanical energy (shaftwork) by the heating (expanding) and cooling (contracting) of a captive gas such as helium or hydrogen.
STRATEGIC PETROLEUM RESERVE (SPR) - The strategic petroleum reserve consists of government owned and controlled crude oil stockpiles stored at various locations in a country. These reserves can be drawn down in response to severe oil supply disruptions.
SUPERCONDUCTOR - A synthetic material that has very low or no electrical resistance. Such experimental materials are being investigated in laboratories to see if they can be created at near room temperatures. If such a superconductor can be found, electrical transmission lines with no little or no resistance may be built, thus conserving energy usually lost in transmission. Superconductors could also have uses in computer chips, solid state devices and electrical motors or generators.
SUPERTANKER - A very large ship designed to transport two or three million barrels of oil.
TAR SANDS - Sedimentary rocks containing heavy oil that cannot be extracted by conventional petroleum recovery methods.
TEMPERATURE - Degree of hotness or coldness measured on one of several arbitrary scales based on some observable phenomenon (such as the expansion).
THERM - One hundred thousand (100,000) British thermal units (1 therm = 100,000 Btu).
THERMAL MASS - A material used to store heat, thereby slowing the temperature variation within a space. Typical thermal mass materials include concrete, brick, masonry, tile and mortar, water, and rock or other materials with high heat capacity.
THERMODYNAMICS - The study of the inter-relation between heat, work and internal energy of as system. There are three laws.
The British scientist and author C.P. Snow had an excellent way of remembering the three laws:
THERMOSTAT - An automatic control device designed to be responsive to temperature and typically used to maintain set temperatures by cycling the HVAC system.
TIDAL POWER - Energy obtained by using the motion of the tides to run water turbines that drive electric generators.
TRANSFORMER - A device, which through electromagnetic induction but without the use of moving parts, transforms alternating or intermittent electric energy in one circuit into energy of similar type in another circuit, commonly with altered values of voltage and current.
URANIUM - A radioactive element, found in ores, of which atoms can be split to create energy.
URANIUM ENRICHMENT - The process of increasing the percentage of pure uranium above the levels found in naturally occurring uranium ore, so that it may be used as fuel.
U-VALUE - The measure of the rate of heat loss through a material. Thus in all aspects of home design one should strive for the lowest U-Values possible because the lower the U-value, the less heat that is needlessly escaping. So for example single glazed windows have a typical U-value of 5.6 while double glazed windows have a typical U-value of 2.8.
VOLT - A unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm.
WATT – The SI unit of power measurement equal to one joule per second.
WATT-HOUR - One watt of power expended for one hour.
WEATHERSTRIPPING - Specially designed strips, seals and gaskets installed around doors and windows to limit air leakage.