Heat exchanger (HX). a device used for transferring energy in the form of heat among two or more fluids of varying temperatures that are in contact thermally with each other. Most adopted heat transfer devices in industries are Shell and Tube Heat Exchangers (S&T HXs) therefore they are most common in many industrial applications such as HVAC. air treatment. https://macorners.shop/product-category/birthstone-gift-box/