Waste heat

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.

[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.

[9] Although small in terms of power, the disposal of waste heat from microchips and other electronic components, represents a significant engineering challenge.

For example, data centers use electronic components that consume electricity for computing, storage and networking.

The French CNRS explains a data center is like a resistor and most of the energy it consumes is transformed into heat and requires cooling systems.

In warm conditions, this heat exceeds a level required for homeostasis in warm-blooded animals, and is disposed of by various thermoregulation methods such as sweating and panting.

An established approach is by using a thermoelectric device,[12] where a change in temperature across a semiconductor material creates a voltage through a phenomenon known as the Seebeck effect.

The benefit is that this process can reject heat at lower temperatures for the production of electricity than the regular water steam cycle.

Limitations to the use of by-product heat arise primarily from the engineering cost/efficiency challenges in effectively exploiting small temperature differences to generate other forms of energy.

The American Meteorological Society defines it as "Heat released to the atmosphere as a result of human activities, often involving combustion of fuels.

Sources include industrial plants, space heating and cooling, human metabolism, and vehicle exhausts.

[17][18] Anthropogenic heat is a small influence on rural temperatures, and becomes more significant in dense urban areas.

Equilibrium climate experiments show statistically significant continental-scale surface warming (0.4–0.9 °C) produced by one 2100 AHF scenario, but not by current or 2040 estimates.

[21] Simple global-scale estimates with different growth rates of anthropogenic heat[23] that have been actualized recently[24] show noticeable contributions to global warming, in the following centuries.

growth rate of waste heat resulted in a 3 degree increase as a lower limit for the year 2300.