What is the purpose of a filter drier in a refrigeration system?

The purpose of a filter drier in a refrigeration system is to remove moisture and solid contaminants from the refrigerant. Moisture in the refrigeration system can react with the refrigerant and oil to form acids and sludge, which can damage the compressor and other components. Solid contaminants, such as dirt, metal particles, and scale, can clog expansion valves and capillary tubes, restricting refrigerant flow and reducing system performance. The filter drier is typically located in the liquid line, before the expansion valve, to protect these critical components. It contains a desiccant material, such as silica gel or molecular sieve, that absorbs moisture from the refrigerant. It also contains a filter that traps solid particles. Over time, the filter drier can become saturated with moisture and contaminants, reducing its effectiveness. Therefore, it is important to replace the filter drier regularly as part of a preventive maintenance program. For example, after a compressor burnout, it is essential to replace the filter drier to remove any acid or contaminants that may have been released into the system. A clogged or saturated filter drier can cause a pressure drop in the liquid line, leading to reduced cooling capacity and potential system failure.