What type of condenser only draws the required quantity of feed water for the boiler?

The correct answer is radial flow condenser. A radial flow condenser is designed such that the cooling water flows radially outward from the center of the condenser, allowing for effective heat transfer while also enabling the system to draw only the precise amount of feed water required for the boiler's operation. This design minimizes waste and optimizes performance by ensuring that only the necessary quantities of water are used, which is crucial for efficiency in a power plant environment.

In contrast, other condenser types may not specifically regulate the feed water quantity with the same precision or may operate under different flow principles that do not prioritize the exact requirement of the boiler. Thus, the radial flow design stands out as the optimal choice for this application.