Which of the following best describes a heat recovery system?

A heat recovery system is designed to capture and reuse waste heat generated from various processes or equipment, making it an efficient way to utilize energy that would otherwise be lost. This process can significantly enhance energy efficiency in heating, ventilation, and air conditioning systems, as well as in industrial processes. By reusing this otherwise wasted thermal energy, these systems can supplement heating needs, reduce fuel consumption, and ultimately save costs and environmental impact.

In contrast, while thermal energy storage systems do involve storing heat for later use, they do not inherently capture and reuse heat from existing processes. Generating heat from electricity pertains to systems like electric heaters, which do not involve recovery but rather conversion. Lastly, systems that reduce air temperature do not necessarily engage in heat recovery; they may simply cool air without capturing and reusing any heat content. Thus, the true essence of a heat recovery system lies in its ability to efficiently repurpose waste heat, making the identified choice the best descriptor.