What is connected to the evaporator in a centrifugal chiller?

In a centrifugal chiller, the component that is directly connected to the evaporator is the compressor. The evaporator is where the refrigerant absorbs heat from the chilled water, turning from a low-pressure liquid into a vapor. This vapor is then drawn into the compressor, where it is compressed to a high pressure and temperature before moving to the condenser.

The function of the expansion valve is to regulate the flow of refrigerant into the evaporator, but it is not directly connected to the evaporator; it typically sits between the condenser and the evaporator in the refrigeration cycle.

A ruptured disc is a safety device designed to rupture at a specific pressure to prevent overpressure situations, and it does not have a direct operational connection to the evaporator in the way the compressor does.

Finally, the condenser is where the refrigerant dissipates heat after being compressed; it receives vapor from the compressor, not from the evaporator. Thus, considering the roles and connections within the system, it is clear that the compressor is the correct answer in terms of being connected to the evaporator in a centrifugal chiller system.