Refrigeration valves contribute to system safety and prevent overpressurization or overcooling through various mechanisms and features:

1. Pressure Relief Valves: These valves are designed to open and release excess pressure in the system when it exceeds a certain set point. This prevents overpressurization and potential damage to the system components. Pressure relief valves are typically installed in the high-pressure side of the system, such as the discharge line.

2. Expansion Valves: These valves regulate the flow of refrigerant into the evaporator coil. They have control mechanisms, such as a diaphragm or thermal bulb, that respond to system conditions, like pressure or temperature. This control helps prevent overcooling by ensuring the correct amount of refrigerant is released into the evaporator coil based on system demand.

3. Thermostatic Expansion Valves (TXV): TXVs are a type of expansion valve that use a temperature-sensing bulb to regulate refrigerant flow. The bulb senses the temperature of the evaporator coil outlet and adjusts the valve's opening accordingly, maintaining a stable superheat level. This prevents overcooling and ensures efficient operation.

4. Solenoid Valves: These valves are electromechanical devices used to control the flow of refrigerant in the system. They can be used to completely shut off refrigerant flow to certain components or sections of the system, providing an extra layer of safety and control.

5. Check Valves: Check valves are one-way valves that allow refrigerant flow in only one direction. They are often used to prevent backflow and ensure proper refrigerant circulation. By preventing reverse flow, they contribute to system safety and prevent overcooling or pressure fluctuations.

By incorporating these valves appropriately within the refrigeration system, the risk of overpressurization and overcooling is minimized, ensuring safe and efficient operation.