What causes a gradual pressure drop in a refrigeration system?

A gradual pressure drop in a refrigeration system is primarily caused by friction in the evaporator and piping. As refrigerant flows through the system, it encounters resistance from various components such as the evaporator coils, pipes, and fittings. This friction leads to energy losses, which translate to a decrease in pressure as the refrigerant moves through the system.

In practical terms, the longer the piping and the more turns or fittings present, the more friction the refrigerant encounters, thus contributing to a gradual decrease in pressure. This phenomenon can be intensified in systems that are not properly sized or where there is a buildup of contaminants within the refrigerant flow path, further promoting friction and energy loss.

Other factors may influence pressure drops but are not primarily responsible for a gradual drop. For example, high temperatures in the condenser may affect overall system efficiency, but they do not directly cause a pressure drop in the manner described. A lack of refrigerant can lead to other issues like reduced cooling capacity, but it typically causes an immediate and significant drop rather than a gradual one. Excessive compressor speed might indicate an operational issue, but it is not a primary cause of a gradual pressure decrease in the system.