Why is a pressure relief valve preferred over a fusible plug in refrigeration systems?

A pressure relief valve is preferred over a fusible plug in refrigeration systems primarily because it minimizes refrigerant loss. When a pressure relief valve activates, it opens to allow excess pressure to escape safely while keeping the refrigerant contained as much as possible. This is particularly important in maintaining system efficiency and safety, as minimizing refrigerant loss helps prevent both environmental impact and operational costs due to refilling the refrigerant.

In contrast, a fusible plug relies on a temperature-sensitive component that melts under specific heat conditions to release pressure. This method can lead to a larger amount of refrigerant being expelled from the system when the plug melts, resulting in greater loss. Therefore, the ability of the pressure relief valve to control excess pressure without releasing excessive refrigerant makes it a preferred choice in refrigeration systems.

Additionally, while factors such as ease of installation and maintenance also play a role in the selection of components, the primary factor in prioritizing a pressure relief valve over a fusible plug is indeed the efficiency in managing refrigerant loss during pressure relief events.