What is a heat exchanger used for in pipefitting?

A heat exchanger is specifically designed to transfer heat between two fluids without allowing them to mix. This is a crucial function in many mechanical and plumbing systems because it facilitates efficient heating or cooling processes. For instance, in a heating system, hot water from a boiler can transfer its heat to a second fluid, like water in a radiator system, without those fluids coming into direct contact. This separation allows for efficient heat transfer while maintaining the integrity of each fluid, which is essential in applications where chemical interactions between the fluids could lead to contamination or deterioration.

The other options focus on different functions that do not align with the primary purpose of a heat exchanger. While water purification and humidity control are essential in various systems, these do not pertain to the primary role of heat exchangers. Similarly, while speed in heating can be a byproduct of heat exchanger efficiency, they are not limited to use only in boiler systems but are instead utilized across a wide range of applications, including refrigeration and HVAC systems.