Energy terms starting with P

255 terms

P N A semiconductor (photovoltaic) device structure in which the junction is formed between a p-type layer and an n-type layer.
P-I-N A semiconductor (photovoltaic) device structure that layers an intrinsic semiconductor between a p-type semiconductor and an n-type semiconductor; this…
P-Type Semiconductor A semiconductor in which holes carry the current; produced by doping an intrinsic semiconductor with an electron acceptor impurity (e.g.
Packing Factor The ratio of solar collector array area to actual land area.
Paleontological resources Fossilized remains, imprints, and traces of plants and animals preserved in rocks and sediments since some past geologic time.
Paleozoic An era of geologic time, from the end of the Precambrian to the beginning of the Mesozoic, spanning the time between 542 and 251 million years ago.
Palm oasis (1) A desert habitat with permanent water or a water table near the surface that supports a canopy of palm trees.
Palustrine wetlands Shallow freshwater wetlands that often support plant communities of trees, shrubs, emergent plants, mosses, or lichens.
Pan evaporation A measurement that combines or integrates the effects of several climate elements: temperature, humidity, solar radiation, and wind.
Pane (Window) The area of glass that fits in the window frame.
Panel (Solar) A term generally applied to individual solar collectors, and typically to solar photovoltaic collectors or modules.
Panel Radiator A mainly flat surface for transmitting radiant energy.
Panemone A drag-type wind machine that can react to wind from any direction.
Parabolic Aluminized Reflector Lamp A type of lamp having a lens of heavy durable glass that focuses the light. They have longer lifetimes with less lumen depreciation than standard…
Parabolic Dish A solar energy conversion device that has a bowl shaped dish covered with a highly reflective surface that tracks the sun and concentrates sunlight on a…
Parabolic solar collector trough See Parabolic trough
Parabolic Trough A solar energy conversion device that uses a trough covered with a highly reflective surface to focus sunlight onto a linear absorber containing a working…
Parabolic trough system See Parabolic trough
Parallel Transmission of all the bits (e.g. in a character) at the same time. If the character has eight bits, there are eight wires.
Parallel Connection A way of joining photovoltaic cells or modules by connecting positive leads together and negative leads together; such a configuration increases the…
Partial cut A harvest method in which portions of a stand of timber are cut during a number of entries over time. Compare precommercial thinning.
Particulate A small, discrete mass of solid or liquid matter that remains individually dispersed in gas or liquid emissions.
Particulate emissions Fine liquid or solid particles discharged with exhaust gases. Usually measured as grains per cubic foot or pounds per million Btu input.
Particulate matter Fine solid or liquid particles such as dust, smoke, mist, fumes, or smog, found in air or emissions.
Particulates The fine liquid or solid particles contained in combustion gases. The quantity and size of particulates emitted by cars, power and industrial plants, wood…
Passenger-Miles per Gallon Pmpg is the vehicle miles per gallon multiplied by the number of passengers traveling in the vehicle.
Passerine Birds of the order Passeriformes, which includes perching birds and songbirds such as the jays, blackbirds, finches, warblers, and sparrows.
Passivation A chemical reaction that eliminates the detrimental effect of electrically reactive atoms on a photovoltaic cell's surface.
Passive Solar (Building) Design A building design that uses structural elements of a building to heat and cool a building, without the use of mechanical equipment, which requires careful…
Passive solar energy system Solar heating or cooling that uses natural energy flows to transfer heat.
Passive Solar Heater A solar water or space-heating system in which solar energy is collected, and/or moved by natural convection without using pumps or fans.
Passive Solar Home A house built using passive solar design techniques.
Passive/Natural Cooling To allow or augment the natural movement of cooler air from exterior, shaded areas of a building through or around a building.
Patterned-body anthropomorphs Object or drawing having a human shape with a pattern or design. See also Anthropomorphic; Anthropomorphism
Payback Period The amount of time required before the savings resulting from your system equal the system cost.
PCB´s Polychlorinated biphenyls. A group of organic compounds. PCB´s are highly toxic to aquatic life.
Peak Clipping/Shaving The process of implementing measures to reduce peak power demands on a system.
Peak Demand/Load The maximum energy demand or load in a specified time period.
Peak flow The highest flow of water attained during a particular flood for a given stream or river.
Peak horizontal acceleration See Acceleration
Peak load, peak demand These two terms are used interchangeably to denote the maximum power requirement of a system at a given time, or the amount of power required to supply…
Peak Power Power generated that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.
Peak Shifting The process of moving existing loads to off-peak periods.
Peak Sun Hours The equivalent number of hours per day when solar irradiance averages 1 kW/m2. For example, six peak sun hours means that the energy received during total…
Peak Watt A unit used to rate the performance of a solar photovoltaic (PV) cells, modules, or arrays; the maximum nominal output of a PV device, in Watts (Wp) under…
Peak Wind Speed The maximum instantaneous wind speed (or velocity) that occurs within a specific period of time or interval.
Peaking capacity Power generation equipment or system capacity to meet peak power demands.
Peaking Hydropower A hydropower plant that is operated at maximum allowable capacity for part of the day and is either shut down for the remainder of the time or operated at…
Peakshaving LNG facility A liquefied natural gas plant that supplies a gas pipeline system during peak-use periods. During slack periods the liquefied gas is stored.
Peanut-body anthropomorphs Object or drawing having a human-like shape resembling that of a peanut. See also Anthropomorphic; Anthropomorphism
Pediment 1. The triangular space forming the gable end of a roof above the horizontal cornice. 2. An ornamental gable, usually triangular, above a door or window.
Pellet Stove A space heating device that burns pellets; are more efficient, clean burning, and easier to operate relative to conventional cord wood burning appliances.
Pellets Solid fuels made from primarily wood sawdust that is compacted under high pressure to form small (about the size of rabbit feed) pellets for use in a…
Pelton Turbine A type of impulse hydropower turbine where water passes through nozzles and strikes cups arranged on the periphery of a runner, or wheel, which causes the…
Penstock A component of a hydropower plant; a pipe that delivers water to the turbine.
Per capita income The average income per person in a given group.
Percolation The filtering of a liquid passed through a medium with many fine spaces.
Perennial allotment A BLM grazing allotment that consistently produces enough perennial forage to support a year round livestock operation.
Perennial streams Streams that flow continuously because they lie at or below the groundwater table, which constantly replenishes them.
Perennial surface water features Surface water features that contain water at all times throughout the year.
Perennial yield (groundwater) The amount of groundwater that can be withdrawn from a groundwater basin over a period of time without exceeding the long-term recharge of the basin or…
Perennial/safe/sustainable yield A specified rate of groundwater pumping that can be sustained for an indefinite period of time without impairing hydrogeologic and ecologic processes…
Perfluorocarbon (PFC) Compounds consisting of carbon and fluorine. They do not deplete the stratospheric ozone but are very strong greenhouse gases with long lifetimes in the…
Perfluorocarbon Tracer Gas Technique (PFT) An air infiltration measurement technique developed by the Brookhaven National Laboratory to measure changes over time (one week to five months) when…
Performance Ratings Solar collector thermal performance ratings based on collector efficiencies, usually expressed in Btu per hour for solar collectors under standard test or…
Performance Zoning Establishes minimum criteria to be used when assessing whether a particular project is appropriate for a certain area; ensures that the end result adheres…
Perimeter Heating A term applied to warm-air heating systems that deliver heated air to rooms by means of registers or baseboards located along exterior walls.
Permeability The rate at which liquids pass through soil or other materials in a specified direction.
Permeance A unit of measurement for the ability of a material to retard the diffusion of water vapor at 73.4 F (23 C).
Permissible Exposure Limit (PPL) The maximum amount or concentration of a chemical that a worker may be exposed to under OSHA regulations.
Permit Any permit other than a Notice to Proceed issued by the Landmarks Preservation Commission in accordance with the Landmarks Law: (a) "PMW shall mean Permit…
Permitted use The forage allocated by, or under the guidance of, an applicable land use plan for livestock grazing in an allotment under a permit or lease; expressed in…
Permittee An individual who holds either a BLM grazing permit or grazing lease that authorizes grazing use of the public lands issued under authority of Section 3…
Personal Protective Equipment (PPE) Clothing or devices worn to help isolate or shield a person from direct exposure to a hazardous material or situation.
Pesticide (PES-tih-side) Any substance that is used to kill insects and other pests.
Pestle An elongated, often cylindrical stone used to pulverize food products and other cultural products in a mortar. See also Mortar
Petrocalcic Soil horizon formed when secondary calcium carbonate accumulates in the subsoil and hardens into a hardpan.
Petroglyph A figure or design carved, abraded, or pecked on rock.
Petroleum Any petroleum-based substance composed of a complex blend of hydrocarbons derived from crude oil, including motor fuel, jet oil, lubricants, petroleum…
PETS Proposed, endangered, threatened, or sensitive species.
PFYC See Potential Fossil Yield Classification
pH A measurement for liquids to determine acidity or alkalinity. On a scale of one to 14, seven is considered neutral.
Phantom Load Any appliance that consumes power even when it is turned off. Examples of phantom loads include appliances with electronic clocks or timers, appliances…
Phase Alternating current is carried by conductors and a ground to residential, commercial, or industrial consumers.
Phase Change A method of storing information on rewritable optical discs.
Phase-Change Material A material that can be used to store thermal energy as latent heat. Various types of materials have been and are being investigated such as inorganic…
phloem Specialized vascular plant tissue for the transport of assimilates (generally sugars) from the point of synthesis (in the leaf) to other parts of the…
Phosphorous A chemical element used as a dopant in making n-type semiconductor layers. An essential chemical food element that can contribute to the eutrophication of…
Photobiological Hydrogen Production A hydrogen production process that process uses algae. Under certain conditions, the pigments in certain types of algae absorb solar energy.
photoconversion Conversion of light into other forms of energy by chemical, biological, or physical processes.
Photocurrent An electric current induced by radiant energy.
Photoelectric Cell A device for measuring light intensity that works by converting light falling on, or reach it, to electricity, and then measuring the current; used in…
Photoelectrochemical Cell A type of photovoltaic device in which the electricity induced in the cell is used immediately within the cell to produce a chemical, such as hydrogen…
Photoelectrolysis Hydrogen Production The production of hydrogen using a photoelectrochemical cell.
Photogalvanic Processes The production of electrical current from light.
Photon A photon is both a wave and a particle. A beam of light is composed of these particles.
Photosynthesis A chemical process by which green plants synthesize organic compounds from carbon dioxide and water in the presence of sunlight.
Photovoltaic A system that converts direct sunlight to electricity using semi-conductor materials.
Photovoltaic (Conversion) Efficiency The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.
Photovoltaic (PV) Literally, "light" (photo) and "electricity" (voltaic). The class of equipment used to generate electricity directly from sunlight.