Heat that is produced by a machine that uses energy, as a byproduct of doing work
Thermal oxidizers can use a regenerative process for waste heat from industrial systems.Air conditioning units extract heat from a dwelling interior with coolant, and transfer it to the dwelling exterior as waste. They emit additional heat in their use of electricity to power the devices that pass heat to and from the coolant.
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation.
Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the system (as with heat recovery ventilation in a building).
Thermal energy storage, which includes technologies both for short- and long-term retention of heat or cold, can create or improve the utility of waste heat (or cold). One example is waste heat from air conditioning machinery stored in a buffer tank to aid in night time heating. Another is seasonal thermal energy storage (STES) at a foundry in Sweden. The heat is stored in the bedrock surrounding a cluster of heat exchanger equipped boreholes, and is used for space heating in an adjacent factory as needed, even months later.[1] An example of using STES to use natural waste heat is the Drake Landing Solar Community in Alberta, Canada, which, by using a cluster of boreholes in bedrock for interseasonal heat storage, obtains 97 percent of its year-round heat from solar thermal collectors on the garage roofs.[2][3] Another STES application is storing winter cold underground, for summer air conditioning.[4]
On a biological scale, all organisms reject waste heat as part of their metabolic processes, and will die if the ambient temperature is too high to allow this.
Anthropogenic waste heat can contribute to the urban heat island effect.[5] The biggest point sources of waste heat originate from machines (such as electrical generators or industrial processes, such as steel or glass production) and heat loss through building envelopes. The burning of transport fuels is a major contribution to waste heat.
^Andersson, O.; Hägg, M. (2008), "Deliverable 10 - Sweden - Preliminary design of a seasonal heat storage for IGEIA – Integration of geothermal energy into industrial applications Archived 11 April 2020 at the Wayback Machine, pp. 38–56 and 72–76, retrieved 21 April 2013
^Wong, Bill (June 28, 2011), "Drake Landing Solar Community" Archived 2016-03-04 at the Wayback Machine, IDEA/CDEA District Energy/CHP 2011 Conference, Toronto, pp. 1–30, retrieved 21 April 2013
^Wong B., Thornton J. (2013). Integrating Solar & Heat Pumps. Archived 2013-10-15 at the Wayback Machine Renewable Heat Workshop.
^Paksoy, H.; Stiles, L. (2009), "Aquifer Thermal Energy Cold Storage System at Richard Stockton College" Archived 2014-01-12 at the Wayback Machine, Effstock 2009 (11th International) - Thermal Energy Storage for Efficiency and Sustainability, Stockholm.
^Cite error: The named reference :0 was invoked but never defined (see the help page).
Wasteheat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste...
A wasteheat recovery unit (WHRU) is an energy recovery heat exchanger that transfers heat from process outputs at high temperature to another part of...
shipped as a fully assembled unit from the factory. They can be used in wasteheat or turbine (usually under 20 MW) applications. The packaged HRSG can have...
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efficient use of fuel or heat, because otherwise-wastedheat from electricity generation is put to some productive use. Combined heat and power (CHP) plants...
of combined heat and power (also called cogeneration) or wasteheat recovery. Wasteheat recovery is a process that captures excess heat that would normally...
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modification of land surfaces while wasteheat generated by energy usage is a secondary contributor. A study has shown that heat islands can be affected by proximity...
absorption cycle is used only where heat is more readily available than electricity, such as industrial wasteheat, solar thermal energy by solar collectors...
as heat amplifier and refrigeration). Driven by a high-temperature heat source, the first type absorption heat pump extracts the heat of wasteheat (waste...
operation around 35 heat pumps between 1937 and 1945. The main heat sources were lake water, river water, groundwater, and wasteheat. Particularly noteworthy...
Thermoelectric generators could be used in power plants and factories to convert wasteheat into additional electrical power and in automobiles as automotive thermoelectric...
efficient waste management practice involving the recovery of embedded energy in the waste material. For example, burning the waste to produce heat (and electricity...
Incineration of waste materials converts the waste into ash, flue gas and heat. The ash is mostly formed by the inorganic constituents of the waste and may take...
ownership of the SoC. Finally, wasteheat from high energy consumption can damage other circuit components if too much heat is dissipated, giving another...
The fluid allows heat recovery from lower-temperature sources such as biomass combustion, industrial wasteheat, geothermal heat, solar ponds etc. The...
uranium and their daughter nuclides. A large nuclear power plant may reject wasteheat to a natural body of water; this can result in undesirable increase of...
modules get larger as each layer must remove both the heat moved by the above layer and the wasteheat of the layer. Requirements for thermoelectric materials:...
heat/power conversion system. The heat is supplied externally to a closed loop with some of the heat added being converted to work and the wasteheat...
towers, which transfer wasteheat to the atmosphere through evaporation and/or heat transfer cogeneration, a process where wasteheat is recycled for domestic...
An exhaust heat recovery system turns wasteheat energy in exhaust gases into electric energy for batteries or mechanical energy reintroduced on the crankshaft...
subtract the heat of vaporization of the water from the higher heating value. This treats any H2O formed as a vapor that is released as a waste. The energy...
remarkable attention to recover wasteheat from various industries and to optimize the units which are used to absorb heat from waste gases. Thus, these attempts...
efficiency of a fuel cell is generally between 40 and 60%; however, if wasteheat is captured in a cogeneration scheme, efficiencies of up to 85% can be...
such as heterogeneous catalysts, activated charcoal, capturing and using wasteheat to provide cold water for air conditioning and other process requirements...
Computer cooling is required to remove the wasteheat produced by computer components, to keep components within permissible operating temperature limits...
The Cyclone WasteHeat Engine (WHE) is a small steam engine developed to produce power from steam created from wasteheat. It is an offshoot of the development...
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