Waste heat

Waste heat is heat given off as a byproduct of a machine or process that uses energy to do work; the laws of thermodynamics guarantee that every such process gives off some. It has lower utility, meaning lower exergy or higher entropy, than the energy it came from, and it is produced by sources ranging from incandescent light bulbs and warm electronic components to internal combustion engine exhaust and buildings during peak use. Rather than simply being released to the environment, waste heat can sometimes be captured and reused, for instance to heat a vehicle from its own engine coolant, or partly recirculated within the same process; thermal energy storage can extend its usefulness further, for example by storing heat from air conditioning in buffer tanks for use at night. Human generated waste heat from power generation, industry and transport also contributes to the urban heat island effect. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/