Energy terms starting with H

142 terms

Habitat The natural environment where people, animals and plants live. In an aquatic environment, it includes the water, topography, structure and cover present…
Habitat alteration A change in the particular environment or place where an organism or species lives.
Habitat degradation Decline in habitat quality that accompanies non-natural forms of disturbance.
Habitat Fragmentation Division of large tracts of natural habitat into smaller, disjunct parcels.
Habitat generalist (species) See Generalist
Habitat type An aggregation of all land areas potentially capable of producing similar plant communities at climax.
Half-graben A geological term that describes a sedimentary basin where one side is bounded by a normal (extensional) fault.
Hammermill A device consisting of a rotating head with free-swinging hammers which reduce chips or hogged fuel to a predetermined particle size through a perforated…
Hand pile A pile of slash constructed by a crew, not by machine. Hand piles are typically less than 10´ high and less than 12´ in diameter.
Harassment The intentional or unintentional disturbance of individual animals causing them to flee a site or avoid use of an area.
Hardpan A dense, often impermeable soil horizon cemented with silica, iron oxides, calcium carbonate, or organic matter.
hardwood One of the botanical groups of dicotyledonous trees that have broad leaves in contrast to the conifers or softwoods.
Hardwoods Usually broad-leaved and deciduous trees.
Harmonic(s) A sinusoidal quantity having a frequency that is an integral multiple of the frequency of a periodic quantity to which it is related.
Hazardous air pollutant (HAP) Substances that have adverse impacts on human health when present in ambient air.
Hazardous material Any material that poses a threat to human health and/or the environment. Hazardous materials are typically toxic, corrosive, ignitable, explosive, or…
Hazardous waste By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed.
Head The upper horizontal part of a window frame or window opening.
Header A masonry wall unit of brick which is laid so that its short end is exposed.
Headwater (1) The source and upper reaches of a stream; also the upper reaches of a reservoir; (2) the water upstream from a structure or point on a stream; (3) the…
Heat Pressure and intimidation used by a casino to discourage card counters.
Heat Absorbing Window Glass A type of window glass that contains special tints that cause the window to absorb as much as 45% of incoming solar energy, to reduce heat gain in an…
Heat Balance Energy output from a system that equals energy input.
Heat Content The amount of heat in a quantity of matter at a specific temperature and pressure.
Heat Engine A device that produces mechanical energy directly from two heat reservoirs of different temperatures.
Heat Exchanger A device used to transfer heat from a fluid (liquid or gas) to another fluid where the two fluids are physically separated.
Heat Gain The amount of heat introduced to a space from all heat producing sources, such as building occupants, lights, appliances, and from the environment, mainly…
Heat Loss The heat that flows from the building interior, through the building envelope to the outside environment.
Heat Pipe A device that transfers heat by the continuous evaporation and condensation of an internal fluid.
Heat Pump An electricity powered device that extracts available heat from one area (the heat source) and transfers it to another (the heat sink) to either heat or…
Heat Pump Water Heaters A water heater that uses electricity to move heat from one place to another instead of generating heat directly.
Heat rate The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net…
Heat Recovery Ventilator A device that captures the heat from the exhaust air from a building and transfers it to the supply/fresh air entering the building to preheat the air and…
Heat Register The grilled opening into a room by which the amount of warm air from a furnace can be directed or controlled; may include a damper.
Heat Sink A structure or media that absorbs heat.
Heat Source A structure or media from which heat can be absorbed or extracted.
Heat Storage A device or media that absorbs heat for storage for later use.
Heat Storage Capacity The amount of heat that a material can absorb and store.
Heat Transfer The flow of heat from one area to another by conduction, convection, and/or radiation. Heat flows naturally from a warmer to a cooler material or space.
Heat transfer efficiency The useful heat output released to a room divided by the actual heat produced in the firebox.
Heat Transfer Fluid A gas or liquid used to move heat energy from one place to another; a refrigerant.
Heat transfer fluid (HTF) Fluids that transfer heat generated at the solar collectors to a heat exchanger where steam is produced to run a steam generator.
Heat Transmission Coefficient Any coefficient used to calculate heat transmission by conduction, convection, or radiation through materials or structures.
Heating Capacity (Also specific heat) The quantity of heat necessary to raise the temperature of a specific mass of a substance by one degree.
Heating Degree Day(s) (HDD) The number of degrees per day that the daily average temperature (the mean of the maximum and minimum recorded temperatures) is below a base temperature…
Heating degree days (HDD) A measure of heating demand equal to the number of degrees a location’s mean daily temperature was below 65 degrees Fahrenheit.
Heating Fuel Units Standardized weights or volumes for heating fuels.
Heating Fuels Any gaseous, liquid, or solid fuel used for indoor space heating.
Heating Load The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.
Heating Season The coldest months of the year; months where average daily temperatures fall below 65 degrees Fahrenheit creating demand for indoor space heating.
Heating Seasonal Performance Factor (HSPF) The measure of seasonal or annual efficiency of a heat pump operating in the heating mode.
Heating Value The amount of heat produced from the complete combustion of a unit of fuel. The higher (or gross) heating value is that when all products of combustion…
Heating, Ventilation, and Air-Conditioning (HVAC) System All the components of the appliance used to condition interior air of a building.
Heavy metals Metallic elements with high atomic weights (e.g., mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend…
Hectare An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
Hedging Hedging is an investment technique designed to offset a potential loss on one investment by purchasing a second investment that you expect to perform in…
Hedonic – (modeling approach) The hedonic method is a regression technique used to estimate the prices of qualities or models that are not available on the market in particular…
Hedonic statistical framework A method of assessing the impact of various structural (number of bedrooms, bathrooms, square footage, age, etc.
Heliochemical Process The utilization of solar energy through photosynthesis.
Heliodon A device used to simulate the angle of the sun for assessing shading potentials of building structures or landscape features.
Heliostat A device that tracks the movement of the sun; used to orient solar concentrating systems.
Heliothermal Any process that uses solar radiation to produce useful heat.
Heliothermic Site planning that accounts for natural solar heating and cooling processes and their relationship to building shape, orientation, and siting.
Heliothermometer An instrument for measuring solar radiation.
Heliotropic Any device (or plant) that follows the sun's apparent movement across the sky.
hemicellulose Any cellulose-like carbohydrate, but excluding cellulose itself. Together with pectin and lignin, hemicelluloses form the cell wall matrix.
Hemispherical Bowl Technology A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.
Henry Hub A location near the coastal town of Egan, LA and the Texas border where more than a dozen major natural gas pipelines converge and exchange gas.
Herbaceous The plant strata that contain soft, not woody, stemmed plants that die to the ground in winter.
herbaceous energy crops Perennial non-woody crops that are harvested annually, though they may take two to three years to reach full productivity.
herbaceous plants Non-woody species of vegetation, usually of low lignin content such as grasses.
Herbicide A chemical that kills plants.
Herd Area (HA) Following passage of the Wild Free-Roaming Horses and Burros Act (WFRHBA) in 1971, the Bureau of Land Management was directed to identify areas where wild…
Herd Management Area (HMA) An area that has been designated for management of wild horses and/or burros.
Herpetofauna Amphibian and reptile species including frogs, toads, salamanders, turtles, lizards, and snakes.
Hertz A measure of the number of cycles or wavelengths of electrical energy per second; U.S. electricity supply has a standard frequency of 60 hertz.
Hertz (Hz) The unit of measurement of frequency, equivalent to one cycle per second.
Heterogeneity See: genetic heterogeneity.
Heterojunction A region of electrical contact between two different materials.
hexose Any of various simple sugars that have six carbon atoms per molecule (e.g. glucose, mannose, and galactose.)
Hibernacula Caves or other structures used by bats for hibernation.
High liquefaction potential Refers to the susceptibility of soils to liquefy when subjected to sudden loading, such as intense ground shaking from an earthquake.
High-Intensity Discharge Lamp A lamp that consists of a sealed arc tube inside a glass envelope, or outer jacket.
High-Pressure Sodium Lamp A type of High-Intensity Discharge (HID) lamp that uses sodium under high pressure as the primary light-producing element.
Higher Heating Value (HHV) The maximum heating value of a fuel sample, which includes the calorific value of the fuel (bone dry) and the latent heat of vaporization of the water in…
Higher Lubricity The ability to reduce friction—usually in fuel pumps and fuel injectors.
Highly discordant land use Refers to development that is at variance with the existing condition of the land. It might also be described as incongruous.
Hirschman-Herfindahl Index (HHI) Market share analysis The sum of the squares of the market shares of firms competing in a market. HHI is a commonly accepted measure of market concentration.
Historic The time period after the appearance of written records. In the New World, this generally refers to the time period after the beginning of European…
Historic Area An area or building in which historic events occurred, or one which has special value due to architectural or cultural features relating to the heritage…
Historic floodplain An area larger than the 100-year floodplain.
Historic properties Any prehistoric or historic districts, sites, buildings, structures, or objects included in, or eligible for inclusion in, the National Register of…
Historic resources Material remains and the landscape alterations that have occurred since the arrival of Euro-Americans.
Hog fuel or hogged fuel Wood residues processed through a chipper or mill to produce coarse chips normally used for fuel.
Hogbacks An eroded steep ridge of resistant rocks produced by erosion of the broken edges of highly tilted strata.
Hole The vacancy where an electron would normally exist in a solid; behaves like a positively charged particle.
holocellulose The total carbohydrate fraction of wood; cellulose plus hemicellulose.
Holocene The past 10,000 years of geologic time. The most recent epoch of the Quaternary period.
Home Energy Rating Systems (HERS) A nationally recognized energy rating program that gives builders, mortgage lenders, secondary lending markets, homeowners, sellers, and buyers a precise…
Homojunction The region between an n-layer and a p-layer in a single material, photovoltaic cell.