Waste heat

Waste heat is thermal energy released by a process without being captured for its intended work. It can be rejected to the surroundings or recovered for another use.

Thermodynamic efficiency: The ratio of useful output from a thermodynamic process to the energy or exergy supplied. It measures how much supplied energy avoids becoming unrecovered heat.
Waste heat recovery: The capture and reuse of thermal energy that would otherwise leave a process unused. It is the direct strategy for turning discarded process heat into a resource.
Thermal pollution: Human-caused changes in the temperature of natural water or air that harm organisms or ecosystems. Heat discharged into waterways can raise temperatures and disrupt aquatic life.
Energy loss: A reduction in energy available for a chosen purpose, often through transfer or conversion into less useful forms. Waste heat is one specific form of energy no longer available for the intended task.
Carnot cycle: An ideal reversible thermodynamic cycle that sets the maximum efficiency for converting heat between two temperatures. Its temperature limits explain why heat engines must reject some heat.
District heating: A system that distributes heat from centralized sources to buildings through a network of pipes. Networks can deliver recovered industrial heat to nearby buildings.
Cooling tower: A structure that removes heat from water by transferring it to the atmosphere, usually through evaporation. Power plants and factories use towers to reject heat they cannot use.
Heat loss: The transfer of thermal energy from a warmer system to its cooler surroundings. Heat loss describes the transfer; waste heat emphasizes energy's unused status.
Heat exchanger: A device that transfers thermal energy between fluids at different temperatures without necessarily mixing them. It transfers process heat to a useful stream or another process.
Organic Rankine cycle: A heat-engine cycle using an organic working fluid to generate power from relatively low-temperature heat. It can generate electricity from heat too cool for conventional steam cycles.

Linked from 13 pages