Refrigerant cores are components of a refrigeration system that are designed to filter and clean the refrigerant. They are typically made of a porous material, such as activated carbon or molecular sieve, which is able to trap and remove contaminants from the refrigerant. Refrigerant cores are important because contaminants in the refrigerant can cause damage to the compressor and other components of the system, as well as reduce the efficiency of the system. Common contaminants include moisture, acid, and particulates such as dirt and metal shavings. The refrigerant core is typically located in the liquid line of the refrigeration system, between the condenser and the expansion valve. The refrigerant passes through the core, where contaminants are removed, before continuing on to the evaporator.