What in a refrigeration system determines the low-side pressure?

In a refrigeration system, the low-side pressure is primarily determined by the amount of refrigerant and its state in the evaporator. The low side of the refrigeration cycle is where the evaporator operates, and it is essential for absorbing heat from the environment to cool the space. The amount of liquid refrigerant in the system plays a critical role in this process.

When the system has the appropriate amount of refrigerant, it ensures that the evaporator can properly vaporize the liquid refrigerant at the low-side pressure. If the refrigerant level is too low, the evaporator might not be able to maintain the required low pressure for effective heat absorption, leading to inadequate cooling. Conversely, if there is too much refrigerant, it can result in flooding, which also disrupts the proper pressure balance.

Thus, maintaining the right quantity of liquid in the system is key to establishing the desired low-side pressure, as it directly affects the refrigerant's ability to change state from liquid to vapor and absorb heat effectively.