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Energy.gov - Energy industry terms Category: Earth and Environment > Energy industry terms Date & country: 26/02/2017, USA Words: 1299

Resource Recovery
The process of converting municipal solid waste to energy and/or recovering materials for recycling.

Restructuring
The process of changing the structure of the electric power industry from one of guaranteed monopoly over service territories, as established by the Public Utility Holding Company Act of 1935, to one of open competition between power suppliers for customers in any area.

Renewable Energy
Energy derived from resources that are regenerative or for all practical purposes can not be depleted. Types of renewable energy resources include moving water (hydro, tidal and wave power), thermal gradients in ocean water, biomass, geothermal energy, solar energy, and wind energy. Municipal solid waste (MSW) is also considered to be a renewable energy resource.

Resistance
The inherent characteristic of a material to inhibit the transfer of energy. In electrical conductors, electrical resistance results in the generation of heat. Electrical resistance is measured in Ohms. The heat transfer resistance properties of insulation products are quantified as the R-value.

Reliability
This is the concept of how long a device or process can operate properly without needing maintenance or replacement.

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

Relative Humidity
A measure of the percent of moisture actually in the air compared with what would be in it if it were fully saturated at that temperature. When the air is fully saturated, its relative humidity is 100 percent.

Regenerative Cooling
A type of cooling system that uses a charging and discharging cycle with a thermal or latent heat storage subsystem.

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

Refrigeration Cycle
The complete cycle of stages (evaporation and condensation) of refrigeration or of the refrigerant.

Refuse-Derived Fuel
(RDF) A solid fuel produced by shredding municipal solid waste (MSW). Noncombustible materials such as glass and metals are generally removed prior to making RDF. The residual material is sold as-is or compressed into pellets, bricks, or logs. RDF processing facilities are typically located near a source of MSW, while the RDF combustion facility can be located elsewhere. Existing RDF facilities process between 100 and 3,000 tons per day.

Refrigeration Capacity
A measure of the effective cooling capacity of a refrigerator, expressed in Btu per hour or in tons, where one (1) ton of capacity is equal to the heat required to melt 2,000 pounds of ice in 24 hours or 12,000 Btu per hour.

Refrigeration
The process of the absorption of heat from one location and its transfer to another for rejection or recuperation.

Refrigerant
The compound (working fluid) used in air conditioners, heat pumps, and refrigerators to transfer heat into or out of an interior space. This fluid boils at a very low temperature enabling it to evaporate and absorb heat.

Refraction
The change in direction of a ray of light when it passes through one media to another with differing optical densities.

Reflective Window Films
A material applied to window panes that controls heat gain and loss, reduces glare, minimizes fabric fading, and provides privacy. These films are retrofitted on existing windows.

Reflector Lamps
A type of incandescent lamp with an interior coating of aluminum that reflects light to the front of the bulb. They are designed to spread light over specific areas.

Reflective Insulation
(see also radiant barrier) An aluminum foil fabricated insulator with backings applied to provide a series of closed air spaces with highly reflective surfaces.

Reflective Glass
A window glass that has been coated with a reflective film and is useful in controlling solar heat gain during the summer.

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

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

Recurrent Costs
Costs that are repetitive and occur when an organization produces similar goods or services on a continuing basis.

Recycling
The process of converting materials that are no longer useful as designed or intended into a new product.

Reflectance
The amount (percent) of light that is reflected by a surface relative to the amount that strikes it.

Recirculated Air
Air that is returned from a heated or cooled space, reconditioned and/or cleaned, and returned to the space.

Recirculation Systems
A type of solar heating system that circulate warm water from storage through the collectors and exposed piping whenever freezing conditions occur; obviously a not very efficient system when operating in this mode.

Receiver
The component of a central receiver solar thermal system where reflected solar energy is absorbed and converted to thermal energy.

Real Price
The unit price of a good or service estimated from some base year in order to provide a consistent means of comparison.

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

Rayleigh Frequency Distribution
A mathematical representation of the frequency or ratio that specific wind speeds occur within a specified time interval.

Reactive Power
The electrical power that oscillates between the magnetic field of an inductor and the electrical field of a capacitor. Reactive power is never converted to non-electrical power. Calculated as the square root of the difference between the square of the kilovolt-amperes and the square of the kilowatts. Expressed as reactive volt-amperes.

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

Rated Life
The length of time that a product or appliance is expected to meet a certain level of performance under nominal operating conditions; in a luminaire, the period after which the lumen depreciation and lamp failure is at 70% of its initial value.

Radioactive Waste
Materials left over from making nuclear energy. Radioactive waste can harm living organisms if it is not stored safely.

Radon
A naturally occurring radioactive gas found in the U.S. in nearly all types of soil, rock, and water. It can migrate into most buildings. Studies have linked high concentrations of radon to lung cancer.

Rafter
A construction element used for ceiling support.

Rammed Earth
A construction material made by compressing earth in a form; used traditionally in many areas of the world and widely throughout North Africa and the Middle East.

Radiation
The transfer of heat through matter or space by means of electromagnetic waves.

Radiative Cooling
The process of cooling by which a heat absorbing media absorbs heat from one source and radiates the heat away.

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

Radiator Vent
A device that releases pressure within a radiator when the pressure inside exceeds the operating limits of the vent.

Radiant Energy
Energy that transmits away from its source in all directions.

Radiant Floor
A type of radiant heating system where the building floor contains channels or tubes through which hot fluids such as air or water are circulated. The whole floor is evenly heated. Thus, the room heats from the bottom up. Radiant floor heating eliminates the draft and dust problems associated with forced air heating systems.

Radiant Heating System
A heating system where heat is supplied (radiated) into a room by means of heated surfaces, such as electric resistance elements, hot water (hydronic) radiators, etc.

Rate Schedule
A mechanism used by electric utilities to determine prices for electricity; typically defines rates according to amounts of power demanded/consumed during specific time periods.

Radiant Barrier
A thin, reflective foil sheet that exhibits low radiant energy transmission and under certain conditions can block radiant heat transfer; installed in attics to reduce heat flow through a roof assembly into the living space.

Radiant Ceiling Panels
Ceiling panels that contain electric resistance heating elements embedded within them to provide radiant heat to a room.

Quad
One quadrillion Btu. (1,000,000,000,000,000 Btu)

Qualifying Facility
A category of electric power producer established under the Public Utility Regulatory Policy Act (PURPA) of 1978, that includes small-power producers (SPP) who use renewable sources of energy such as biomass, geothermal, hydroelectricity, solar (thermal and photovoltaic), and wind, or cogenerators who produce both heat and electricity using any type of fuel. PURPA requires utilities to purchase electricity from these power producers at a rate approved by a state utility regulatory agency under Federal guidelines. PURPA also requires power providers to sell electricity to these producers. Some states have developed their own programs for SPPs and utilities.

Pyrheliometer
A device that measures the intensity of direct beam solar radiation.

Pyrolysis
The transformation on a compound or material into one or more substances by heat alone (without oxidation). Often called destructive distillation. Pyrolysis of biomass is the thermal degradation of the material in the absence of reacting gases, and occurs prior to or simultaneously with gasification reactions in a gasifier. Pyrolysis products consist of gases, liquids, and char generally. The liquid fraction of pyrolisized biomass consists of an insoluble viscous tar, and pyroligneous acids (acetic acid, methanol, acetone, esters, aldehydes, and furfural). The distribution of pyrolysis products varies depending on the feedstock composition, heating rate, temperature, and pressure.

Pyranometer
A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.

Pulse-Width-Modulated (PWM) Wave Inverter
A type of power inverter that produce a high quality (nearly sinusoidal) voltage, at minimum current harmonics.

Pumped Storage Facility
A type of power generating facility that pumps water to a storage reservoir during off-peak periods, and uses the stored water (by allowing it to fall through a hydro turbine) to generate power during peak periods. The pumping energy is typically supplied by lower cost base power capacity, and the peaking power capacity is of greater value, even though there is a net loss of power in the process.

Public Utility Holding Company Act (PUHCA) of 1935
A law to protect consumers and investors. It placed geographic restrictions on mergers and limitations on diversification into non-utility lines of business and takeovers of electric and gas utilities, and also established regulated monopoly markets or service territories for utilities.

Public Utility or Services Commissions
(PUC or PSC) These are state government agencies responsible for the regulation of public utilities within a state or region. A state legislature oversees the PUC by reviewing changes to power generator laws, rules and regulations and approving the PUC's budget. The commission usually has five Commissioners appointed by the Governor or legislature. PUCs typically regulate: electric, natural gas, water, sewer, telephone services, trucks, buses, and taxicabs within the commission's operating region. The PUC tries to balance the interests of consumers, environmentalists, utilities, and stockholders. The PUC makes sure a region's citizens are supplied with adequate, safe power provider service at reasonable rates.

Public Utilities Regulatory Policy Act (PURPA) of 1978
A law that requires electric utilities to purchase electricity produced from qualifying power producers that use renewable energy resources or are cogenerators. Power providers are required to purchase power at a rate equal to the avoided cost of generating the power themselves. (See Avoided Costs and Qualifying Facility)

Propeller (Hydro) Turbine
A turbine that has a runner with attached blades similar to a propeller used to drive a ship. As water passes over the curved propeller blades, it causes rotation of the shaft.

Psi
Pounds of pressure per square inch.

Psia
Pounds/force per square inch absolute.

Psig
Pounds/force per square inch gauge.

Psychrometer
An instrument for measuring relative humidity by means of wet and dry-bulb temperatures.

Psychrometrics
The analysis of atmospheric conditions, particularly moisture in the air.

Propane
A hydrocarbon gas, C3H8, occurring in crude oil, natural gas, and refinery cracking gas. It is used as a fuel, a solvent, and a refrigerant. Propane liquefies under pressure and is the major component of liquefied petroleum gas (LPG).

Products of Combustion
The elements and compounds that result from the combustion of a fuel.

Programmable Thermostat
A type of thermostat that allows the user to program into the devices' memory a pre-set schedule of times (when certain temperatures occur) to turn on HVAC equipment.

Projected Area
The net south-facing glazing area projected on a vertical plane. Also, the solid area covered at any instant by a wind turbine's blades from the perspective of the direction of the windstream (as opposed to the swept area).

Producer Gas
Low or medium Btu content gas, composed mainly of carbon monoxide, nitrogen(2), and hydrogen(2) made by the gasification of wood or coal.

Primary Air
The air that is supplied to the combustion chamber of a furnace.

Prime Mover
Any machine capable of producing power to do work.

Process Heat
Thermal energy that is used in agricultural and industrial operations.

Pressurization Testing
A technique used by energy auditors, using a blower door, to locate areas of air infiltration by exaggerating the defects in the building shell. This test only measures air infiltration at the time of the test. It does not take into account changes in atmospheric pressure, weather, wind velocity, or any activities the occupants conduct that may affect air infiltration rates over a period of time.

Present Value
The amount of money required to secure a specified cash flow at a future date at a specified return.

Pressure Drop
The loss in static pressure of a fluid (liquid or gas) in a system due to friction from obstructions in pipes, from valves, fittings, regulators, burners, etc, or by a breech or rupture of the system.

Preheater
(Solar) A solar heating system that preheats water or air that is then heated more by another heating appliance.

Power Transmission Line
An electrical conductor/cable that carries electricity from a generator to other locations for distribution.

Power Factor
(PF) The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

Power Provider
A company or other organizational unit that sells and distributes electrical power (e.g., private or public electrical utility), either to other distribution and wholesale businesses or to end-users. Sometimes power providers also generate the power they sell.

Power Density
The amount of power per unit area of a free windstream.

Power Conditioning
The process of modifying the characteristics of electrical power (for e.g., inverting dc to ac).

Power (Output) Curve
A plot of a wind energy conversion device's power output versus wind speed.

Power (Solar) Tower
A term used to describe solar thermal, central receiver, power systems, where an array of reflectors focus sunlight onto a central receiver and absorber mounted on a tower.

Power Coefficient
The ratio of power produced by a wind energy conversion device to the power in a reference area of the free windstream.

Pound Per Square Inch Absolute
(psia) A unit of pressure [hydraulic (liquid) or pneumatic (gas)] that does not include atmospheric pressure.

Power
Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.

Pound of Steam
One pound of water in vapor phase; is NOT steam pressure, which is expressed as pounds per square inch (psi).

Potential Energy
Energy available due to position.

Potable Water
Water that is suitable for drinking, as defined by local health officials.

Porous Media
A solid that contains pores; normally, it refers to interconnected pores that can transmit the flow of fluids. (The term refers to the aquifer geology when discussing sites for CAES.)

Portfolio Standard
The requirement that an electric power provider generate or purchase a specified percentage of the power it supplies/sells from renewable energy resources, and thereby guarantee a market for electricity generated from renewable energy resources.

Polyethylene
A registered trademark for plastic sheeting material that can be used as a vapor retarder. This plastic is used to make grocery bags. It is a long chain of carbon atoms with 2 hydrogen atoms attached to each carbon atom.

Plug Flow Digester
A type of anaerobic digester that has a horizontal tank in which a constant volume of material is added and forces material in the tank to move through the tank and be digested.

Point-Contact Cell
A high efficiency silicon photovoltaic concentrator cell that employs light trapping techniques and point-diffused contacts on the rear surface for current collection.

Polycrystalline
A semiconductor (photovoltaic) material composed of variously oriented, small, individual crystals.

Plenum
The space between a hanging ceiling and the floor above or roof; usually contains HVAC ducts, electrical wiring, fire suppression system piping, etc.

Photovoltaic-Thermal (PV/T) Systems
A solar energy system that produces electricity with a PV module, and collects thermal energy from the module for heating. There are no commercially available systems available (as of 11/97).

Physical Vapor Deposition
A method of depositing thin semiconductor photovoltaic) films. With this method, physical processes, such as thermal evaporation or bombardment of ions, are used to deposit elemental semiconductor material on a substrate.

Pitch Control
A method of controlling a wind turbine's speed by varying the orientation, or pitch, of the blades, and thereby altering its aerodynamics and efficiency.

Photovoltaic Peak Watt
see Peak Watt.

Photovoltaic Device
A solid-state electrical device that converts light directly into direct current electricity of voltage-current characteristics that are a function of the characteristics of the light source and the materials in and design of the device. Solar photovoltaic devices are made of various semi-conductor materials including silicon, cadmium sulfide, cadmium telluride, and gallium arsenide, and in single crystalline, multi-crystalline, or amorphous forms.