Heat transfer

In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not contain heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system.

The calorie is a unit of energy that originated from the caloric theory of heat. The small calorie or gram calorie is defined as the amount of heat needed to raise the temperature of one milliliter of water by one degree Celsius (or one kelvin). In the US, "large calorie" is also used to mean kilocalorie (1 kcal = 1000 cal) .

thumb|right|Rolling boil of water in an electric kettle

transport of thermal energy in physical systems

idealized physical body that absorbs all incident electromagnetic radiation

capacity of a material to conduct heat

electromagnetic radiation generated by the thermal motion of charged particles in matter

transfer of internal energy within a body due to particle collisions & electron movements

physical law on the emissive power of black body

tendency of matter to change volume in response to a change in temperature

Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment (the study of such processes in zoology has been called physiological ecology

piece of equipment built for efficient heat transfer from one medium to another

upright=1.2|thumb|The world's first ice-calorimeter, used in the winter of 1782–83, by Antoine Lavoisier and [[Pierre-Simon Laplace, to determine the heat involved in various chemical changes; calculations which were based on Joseph Black's prior discovery of latent heat. These experiments mark the foundation of thermochemistry.]] thumb|upright|Snellen direct calorimetry chamber, University of Ottawa thumb|Indirect calorimetry metabolic cart measuring oxygen uptake and production of a spontaneously breathing subject (dilution method with canopy hood).

insulation against heat transfer

In the fields of physics, engineering, and earth sciences, advection is the transport of a substance or quantity by bulk motion of a fluid. The properties of that substance are carried with it. Generally the majority of the advected substance is also a fluid. The properties that are carried with the advected substance are conserved properties such as energy. An example of advection is the transport of pollutants or silt in a river by bulk water flow downstream. Another commonly advected quantity is energy or enthalpy. Here the fluid may be any material that contains thermal energy, such as wat

thermal electromagnetic radiation

device used to condense a substance from its gaseous to its liquid state

physical phenomenon in which a liquid close to a very hot surface produces an insulating vapor layer keeping the liquid from boiling rapidly

hardware component

partial differential equation for distribution of heat in a given region over time

overview about physical and chemical properties of pure water

layer of fluid in the immediate vicinity of a bounding surface

Efficiency is the often measurable ability to avoid making mistakes or wasting materials, energy, efforts, money, and time while performing a task. In a more general sense, it is the ability to do things well, successfully, and without waste.

thumb|right|Blacksmiths work [[iron when it is hot enough to emit plainly visible thermal radiation.]] The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Thermal radiation is electromagnetic radiation that most commonly includes both visible radiation (light) and infrared radiation, which is not visible to human eyes. A portion of the thermal radiation from very hot objects (see photograph) is easily visible to the eye.

law of wavelength-specific emission and absorption

Effectiveness or effectivity is the capability of producing a desired result or the ability to produce desired output. When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression.

state of no net thermal energy flow between two connected systems

construction element consisting of at least two glass plates for windows and other glazing

characteristic number in fluid dynamics

fluid material squeezed between parts to keep them in close thermal contact

physical quantity that measures the rate of transfer of heat of a material from the hot side to the cold side

device containing volatile liquid in a sealed chamber to transfer heat by conduction and phase transition

measure of heat transfer on a surface

device that rotates under influence of light

analysis of material by examining how it responds to heat

physical law

Waste heat is by necessity produced both by machines that do work and in other processes that use energy, for example in a refrigerator warming the room air or a combustion engine releasing heat into the environment.

characteristic number for heat transfer into a body

protection of buildings against heat transfers

electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules

specified amount of heat a computer component generates under normal conditions that the cooling system must dissipate

satisfaction with the thermal environment

measure of a channel flow efficiency

computer graphics rendering method using diffuse reflection

thumb|A video showing how to make thermochromatic thermal cards based on Cholesteric liquid crystal|cholesteric liquid crystals Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an example of this property used in a consumer product, although thermochromism also has more practical uses, such as for baby bottles that change to a different color when cool enough to drink, or kettles that change color when water is at or near boiling point. Thermochromism is one of several types of chromism.

achieved with greatly differing technologies that collectively accommodate a wide range of needs; allows excess thermal energy to be collected for later use

Thermogenesis is the process of heat production in the metabolism of organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily (Sauromatum venosum), and the giant water lilies of the genus Victoria. The lodgepole pine dwarf mistletoe, Arceuthobium americanum, disperses its seeds explosively through thermogenesis. Thermoregulation is an important component of a homeothermic animal's resting metabolic rate (RMR) and serves to defend body temperature within narrow limits at low or high ambient temperature.

thumb|right|Construction block made from hempcrete thumb|Illustration of hemp concrete carbon emission and sequestration, with a net emissions balance indicating carbon negativity

Heat transfer due to combined effects of advection and diffusion

mechanism occurring in nature and mimicked in industry and engineering

heat released as a result of radioactive decay

device that tends to equalize temperature over its surface

any cooling method that facilitates heat dissipation without additional energy input

higher temperatures due to movement through air

sensory organ in snakes for heat sensing

accounting of the energy flows at and below the planet's crust

physical process in which a thermal gradient causes different parts of an object to expand by different amounts

thermal quality