Which component is primarily responsible for maintaining the flow of refrigerant in a chilled-water system?

The component that plays a critical role in maintaining the flow of refrigerant in a chilled-water system is the pump. This device circulates the refrigerant through the various components of the system, including the evaporator, condenser, and expansion valve, ensuring that the refrigerant can effectively absorb and release heat as needed.

In a chilled-water system, the pump generates the necessary pressure to facilitate the movement of the refrigerant. Without the pump, the refrigerant would not circulate correctly, which could lead to insufficient cooling or heating and overall reduced efficiency of the system.

While other components such as the condenser, evaporator, and expansion valve each perform vital functions related to heat transfer and pressure regulation, they do not serve the primary purpose of controlling the flow of the refrigerant throughout the entire system. The pump is specifically designed for this role, making it the correct choice in this context.