What safety device is used to prevent excessive pressure in refrigeration systems?

The pressure relief valve plays a crucial role in ensuring the safety of refrigeration systems by preventing excessive pressure buildup. In a refrigeration system, pressure can increase due to various factors, such as high ambient temperatures or a malfunctioning component. When the pressure in the system exceeds a certain threshold, the pressure relief valve activates to release excess refrigerant or vapor. This action allows the system to maintain safe operating conditions and prevents potential damage or catastrophic failure, such as ruptures or explosions.

While other devices mentioned in the choices contribute to the overall functionality and efficiency of refrigeration systems, they do not specifically serve the primary purpose of ensuring safety by controlling pressure. The expansion valve regulates the flow of refrigerant, and pressure gauges provide pressure readings but do not prevent pressure increase. Similarly, a thermostatic expansion valve controls refrigerant flow based on temperature, but it does not directly address excessive pressure situations. Thus, the pressure relief valve is essential for maintaining safety by preventing excessive pressures in refrigeration systems.