Which type of pump is commonly used to move chilled water in a central cooling system?

• A. Centrifugal chill water pump
• B. Positive displacement pump
• C. Diaphragm pump
• D. Gear pump

Answer: (A)

Circulating chilled water in a central cooling system relies on a pump that can move large volumes of low-viscosity liquid efficiently and with reliable, moderate pressure. A centrifugal pump fits this need because its impeller accelerates water and then converts that velocity into pressure, delivering high flow rates with relatively simple, robust construction. This makes it well-suited for HVAC circuits where the goal is to move water through long piping and multiple zones, rather than to generate very high pressure or to handle viscous or chemically demanding fluids. In addition, centrifugal pumps are easily matched to variable cooling demand with speed controls, which helps optimize energy use.

Other pump types are better suited to different tasks: positive displacement pumps push a fixed amount per cycle and excel with high pressure or viscous fluids or when precise dosing is required, not for the large-volume, low-viscosity flow typical of chilled-water loops. Diaphragm and gear pumps are often used for chemicals, slurries, or high-pressure applications rather than circulating large volumes of water in a central system.