Tips for Selecting the Right Heat Exchanger for Your Needs Numerous types of heat exchangers cover a broad range of applications. However, this guide covers only the smaller scale, specialty heat exchangers often found in industrial applications, and focuses on the relationship between heat exchangers and sample coolers. A heat exchanger is a device used to transfer heat from one medium to another. They can heat within a process, and may be used within a process to cool a liquid, vapor or gas (referred to as fluid within this guide) to make it safe to handle or transfer.