What is a heat exchanger?

• A. Any piece of equipment that transfers heat from one material to another.
• B. A device that stores heat for later use.
• C. A pump that circulates hot fluid.
• D. A sensor that measures temperature difference.

Answer: (A)

A heat exchanger moves thermal energy from one stream to another without letting the streams mix. It achieves this through a solid barrier (like tubes or plates) that separates the fluids while still allowing heat to pass, driven by the temperature difference between the sides. This setup enables heating or cooling of a process fluid by transferring energy to or from a colder or hotter medium, often with large surface area and specific flow arrangements to maximize efficiency. Examples include shell-and-tube and plate heat exchangers used in power plants, HVAC systems, and chemical processing.

The other options don’t fit because they describe different functions: storing heat for later use, circulating fluid without transferring heat, or measuring temperature differences.