All articles starting with H
20,046 articles
Heat exchanger network retrofit
Heat exchanger network retrofit modifies the heat exchanger network of an existing process plant to improve heat recovery, cutting energy demand and cost by adding area, enhancing heat transfer, or changing structure.
Heat exhaustion
Heat exhaustion is a heat-related illness from excessive water and salt loss through sweating, causing headache, nausea, dizziness, and heavy sweating; treated with cooling and fluids, it can progress to heat stroke if untreated.
Heat fatigue, transient
Heat fatigue, transient (ICD-11 NF01.3) is a mild acute heat effect: impaired performance of skilled sensorimotor, mental, or vigilance tasks in the heat, greatest in unacclimatized workers, prevented by acclimatization and training.
Heat flux
Heat flux, also called thermal flux, is the rate of thermal energy transfer through a surface per unit area, a vector quantity measured in watts per square meter and governed by Fourier's law.
Heat index
The heat index, also called the humiture or temperature-humidity index, combines air temperature and relative humidity to estimate how hot conditions feel to a resting person in the shade.
Heat integration
Heat integration is a chemical engineering design method that matches a plant's heat sources and sinks through pinch analysis, cutting external utility use, often by 20% or more.
Heat lightning
Heat lightning, also called summer lightning, is the light from a distant thunderstorm too far away for thunder to be heard, often seen as silent flickers on hot summer nights.
Heat map
A heat map is a data visualization that encodes values in a two-dimensional matrix or table as colors, so patterns, clusters, and outliers can be read from shaded cells.
Heat of combustion
The heat of combustion, also called the heating value or calorific value, is the energy released when a unit amount of a substance burns completely in oxygen.
Heat pipe
A heat pipe is a sealed, passive device that transfers large amounts of heat through evaporation and condensation of a working fluid, with no moving parts.
Heat pipe heat exchanger
A heat pipe heat exchanger (HPHX) is a passive heat exchanger that transfers heat between two airstreams via sealed heat pipes, with zero cross-contamination and no external power.
Heat pump
A heat pump is a device that moves heat from a cooler place to a warmer place using electricity, providing heating, cooling, and water heating.
Heat pump and refrigeration cycle
The heat pump and refrigeration cycle is a thermodynamic loop in which a working fluid is compressed and expanded to move heat against its natural direction.
Heat pump dryer
A heat pump dryer is a ventless clothes dryer that dries laundry in a closed air loop using a heat pump, saving at least 28% of the energy.
Heat pump water heater
A heat pump water heater is an electric appliance that moves heat from surrounding air into a water tank, delivering two to four times the heat per unit of electricity.
Heat recovery steam generator
A heat recovery steam generator (HRSG) is a boiler that recovers heat from hot gas turbine exhaust to raise steam, most often for a steam turbine.
Heat recovery ventilation
Heat recovery ventilation, also called an air exchanger, is a balanced ventilation method that transfers heat from exhaust air to incoming fresh air, recovering up to 80% of it.
Heat shock protein
Heat shock proteins, also known as stress proteins, are molecular chaperones produced by cells under heat and other stresses, helping other proteins fold and boosting heat tolerance.
Heat sink
A heat sink is a passive heat exchanger that spreads heat from a component such as a semiconductor die over a large finned surface cooled by moving air.
Heat stroke
Heat stroke is a life-threatening emergency with core temperature above 40 °C (104 °F) and CNS dysfunction, in classic (passive heat exposure) and exertional (exercise) forms; treatment is rapid cold-water immersion, with about 5% case fatality.
Heat syncope
Heat syncope (熱失神) is fainting or dizziness from prolonged standing or sudden standing in heat, caused by reduced cerebral blood flow; a mild, self-limiting heat illness treated with rest, cooling, and oral fluids.
Heat transfer
Heat transfer, also known as heat flow or heat transport, is the movement of thermal energy from hotter to cooler regions, occurring by conduction, convection, and radiation.
Heat transfer coefficient
The heat transfer coefficient, or coefficient of heat transmission, relates the rate of heat transfer between a surface and a fluid to the temperature difference.
Heat treating
Heat treating, also called heat treatment, is a manufacturing process of controlled heating and cooling of metals, most significant for steel, whose cooling rate determines whether martensite, bainite, or pearlite forms.
Heat wave
A heat wave is a period of unusually hot weather lasting several days, defined by local thresholds, and human-caused warming has made heat waves more frequent and intense.
Heat Waves
Heat Waves is a 2020 Glass Animals song written by Dave Bayley for the album Dreamland; it set the record 59-week climb to No. 1 on the Billboard Hot 100 in March 2022. The phrase also names prolonged extreme-heat weather events, which have increased in frequency and intensity since the 1950s.
Heat Waves (fan fiction)
Heat Waves is a 2020-2021 DreamNotFound real person fanfic by tbhyourelame on AO3 about Minecraft YouTubers Dream and GeorgeNotFound; it became AO3's most bookmarked work, boosted the Glass Animals song, and was later hidden by its author.
Heat-affected zone
The heat-affected zone (HAZ) is the region of base metal altered by welding or cutting heat without melting, often the weakest part of a joint.
Heat-assisted magnetic recording
Heat-assisted magnetic recording (HAMR) is a hard disk drive technology that briefly heats the disk surface with a laser so data can be written on very stable magnetic materials.
Heat-bath configuration interaction
Heat-bath configuration interaction (HCI) is a selected configuration interaction method in quantum chemistry, introduced by Holmes, Tubman, and Umrigar in 2016, which grows a compact wavefunction by thresholding determinants.