Waste heat is the thermal energy that is produced as a byproduct of various processes, such as electricity generation, industrial manufacturing, and vehicle operation. This heat is often released into the environment without being utilized, leading to energy inefficiency. Capturing and reusing waste heat can improve overall energy efficiency and reduce greenhouse gas emissions. Technologies like heat exchangers and combined heat and power systems are designed to recover this energy, allowing it to be used for heating, cooling, or even electricity generation, thereby maximizing resource use and minimizing waste.