Energy — page 23 of 33

Energy terms

2201. 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…
2202. Passive solar energy system Solar heating or cooling that uses natural energy flows to transfer heat.
2203. 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.
2204. Passive Solar Home A house built using passive solar design techniques.
2205. 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.
2206. Patterned-body anthropomorphs Object or drawing having a human shape with a pattern or design. See also Anthropomorphic; Anthropomorphism
2207. Payback Period The amount of time required before the savings resulting from your system equal the system cost.
2208. PCB´s Polychlorinated biphenyls. A group of organic compounds. PCB´s are highly toxic to aquatic life.
2209. Peak Clipping/Shaving The process of implementing measures to reduce peak power demands on a system.
2210. Peak Demand/Load The maximum energy demand or load in a specified time period.
2211. Peak flow The highest flow of water attained during a particular flood for a given stream or river.
2212. Peak horizontal acceleration See Acceleration
2213. 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…
2214. Peak Power Power generated that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.
2215. Peak Shifting The process of moving existing loads to off-peak periods.
2216. 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…
2217. 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…
2218. Peak Wind Speed The maximum instantaneous wind speed (or velocity) that occurs within a specific period of time or interval.
2219. Peaking capacity Power generation equipment or system capacity to meet peak power demands.
2220. 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…
2221. 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.
2222. Peanut-body anthropomorphs Object or drawing having a human-like shape resembling that of a peanut. See also Anthropomorphic; Anthropomorphism
2223. 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.
2224. 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.
2225. 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…
2226. 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…
2227. Penstock A component of a hydropower plant; a pipe that delivers water to the turbine.
2228. Per capita income The average income per person in a given group.
2229. Percolation The filtering of a liquid passed through a medium with many fine spaces.
2230. Perennial allotment A BLM grazing allotment that consistently produces enough perennial forage to support a year round livestock operation.
2231. Perennial streams Streams that flow continuously because they lie at or below the groundwater table, which constantly replenishes them.
2232. Perennial surface water features Surface water features that contain water at all times throughout the year.
2233. 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…
2234. 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…
2235. Perfluorocarbon (PFC) (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…
2236. Perfluorocarbon Tracer Gas Technique (PFT) (PFT) An air infiltration measurement technique developed by the Brookhaven National Laboratory to measure changes over time (one week to five months) when…
2237. Performance Ratings Solar collector thermal performance ratings based on collector efficiencies, usually expressed in Btu per hour for solar collectors under standard test or…
2238. 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…
2239. 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.
2240. Permeability The rate at which liquids pass through soil or other materials in a specified direction.
2241. Permeance A unit of measurement for the ability of a material to retard the diffusion of water vapor at 73.4 F (23 C).
2242. Permissible Exposure Limit (PPL) (PPL) The maximum amount or concentration of a chemical that a worker may be exposed to under OSHA regulations.
2243. 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…
2244. 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…
2245. 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…
2246. Personal Protective Equipment (PPE) (PPE) Clothing or devices worn to help isolate or shield a person from direct exposure to a hazardous material or situation.
2247. Pesticide (PES-tih-side) Any substance that is used to kill insects and other pests.
2248. Pestle An elongated, often cylindrical stone used to pulverize food products and other cultural products in a mortar. See also Mortar
2249. Petrocalcic Soil horizon formed when secondary calcium carbonate accumulates in the subsoil and hardens into a hardpan.
2250. Petroglyph A figure or design carved, abraded, or pecked on rock.
2251. Petroleum Any petroleum-based substance composed of a complex blend of hydrocarbons derived from crude oil, including motor fuel, jet oil, lubricants, petroleum…
2252. PETS Proposed, endangered, threatened, or sensitive species.
2253. PFYC See Potential Fossil Yield Classification
2254. pH A measurement for liquids to determine acidity or alkalinity. On a scale of one to 14, seven is considered neutral.
2255. 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…
2256. Phase Alternating current is carried by conductors and a ground to residential, commercial, or industrial consumers.
2257. Phase Change A method of storing information on rewritable optical discs.
2258. 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…
2259. 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…
2260. 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…
2261. Photobiological Hydrogen Production A hydrogen production process that process uses algae. Under certain conditions, the pigments in certain types of algae absorb solar energy.
2262. photoconversion Conversion of light into other forms of energy by chemical, biological, or physical processes.
2263. Photocurrent An electric current induced by radiant energy.
2264. 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…
2265. 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…
2266. Photoelectrolysis Hydrogen Production The production of hydrogen using a photoelectrochemical cell.
2267. Photogalvanic Processes The production of electrical current from light.
2268. Photon A photon is both a wave and a particle. A beam of light is composed of these particles.
2269. Photosynthesis A chemical process by which green plants synthesize organic compounds from carbon dioxide and water in the presence of sunlight.
2270. Photovoltaic A system that converts direct sunlight to electricity using semi-conductor materials.
2271. Photovoltaic (Conversion) Efficiency The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.
2272. Photovoltaic (PV) (PV) Literally, "light" (photo) and "electricity" (voltaic). The class of equipment used to generate electricity directly from sunlight.
2273. Photovoltaic (PV) array (PV) An interconnected system of PV modules that function as a single electricity-producing unit.
2274. Photovoltaic (PV) cell (PV) The smallest semiconductor element within a PV module that converts incident sunlight into electrical energy (direct current voltage and current).
2275. Photovoltaic (PV) facility (PV) A solar energy facility that uses photovoltaic cells to produce electricity and that includes all components, such as the PV system, power conditioning…
2276. Photovoltaic (PV) module (PV) An assembly of solar cells (flat-plate type) or receiver(s) and optics (concentrator type) and ancillary parts, such as interconnects and terminals…
2277. Photovoltaic (PV) panel (PV) A collection of modules, either flat-plate or concentrator type, mechanically fastened, electrically interconnected, and designed to provide a…
2278. Photovoltaic (PV) power plant (PV) See Photovoltaic (PV) facility
2279. Photovoltaic (PV) receiver (PV) An assembly of one or more PV cells that accepts concentrated sunlight and incorporates means for thermal and electric energy removal.
2280. Photovoltaic (PV) system (PV) See Photovoltaic (PV) facility
2281. Photovoltaic (PV; Solar) Array A group of solar photovoltaic modules connected together.
2282. Photovoltaic (Solar) Cell Treated semiconductor material that converts solar irradiance to electricity.
2283. Photovoltaic (Solar) Module or Panel A solar photovoltaic product that generally consists of groups of PV cells electrically connected together to produce a specified power output under…
2284. Photovoltaic (Solar) System A complete PV power system composed of the module (or array), and balance-of-system (BOS) components including the array supports, electrical…
2285. 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…
2286. Photovoltaic Peak Watt see Peak Watt.
2287. 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.
2288. Photovoltaics (PV) (PV) Technologies that utilize semiconducting materials that convert sunlight directly into electricity.
2289. Phreatic vegetation Vegetation supported by groundwater below the land surface.
2290. Phreatophytes Any plant, typically living in the desert, that obtains its water from long taproots that reach the water table.
2291. Physical basis Describes a physical natural gas purchase for the following month where the price is tied to the closing price of the expiring Nymex futures contract.
2292. Physical Vapor Deposition A method of depositing thin semiconductor photovoltaic) films. With this method, physical processes, such as thermal evaporation or bombardment of ions…
2293. Physiography The physical geography of an area or the description of its physical features.
2294. Phytoplankton Small, often single-celled plants that live suspended in bodies of water.
2295. Pictograph A design drawn in pigment upon an unprepared or ground rock surface.
2296. Piezometer A nonpumping well, generally of small diameter, for measuring the elevation of a water table.
2297. Piling unmerchantable material (PUM) (PUM) A logging contract requirement to remove and pile unmerchantable woody material of a specified size.
2298. Pilot scale The size of a system between the small laboratory model size (bench scale) and a full-size system.
2299. 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.
2300. Pithouse A semi-subterranean dwelling with an excavated floor and earthen superstructure supported by posts and beams.