In marine air conditioning systems using chillers, the circulation pump is essential to ensure proper flow of the refrigerant fluid—typically a water/glycol mixture—between the chiller and the fan coils. A properly sized and well-maintained pump is key to ensuring optimal performance and system durability.

Flow Rate: How Many Liters per Minute Are Needed?

Flow rate, measured in liters per minute (l/min), is the amount of fluid the pump can move. A common estimate is 2–3 l/min per cooling kW. For example, a 30 kW chiller requires a pump capable of at least 60–90 l/min.

Head Pressure: Overcoming Circuit Resistance

Head represents the energy required by the pump to overcome resistance from the circuit (bends, valves, pipe length, etc.). In marine systems, this value can range from 5 to 20 meters.

Power Supply: Single-Phase and Three-Phase Pumps

• Single-phase (230V): suitable for small systems. Easy to install but less efficient in the long run.
• Three-phase (400V): ideal for chillers above 5 kW. Provide better efficiency, stability, and durability, especially for professional or intensive use.

Recommended Brands

• Frigomar: high-performance integrated pumps, often used with inverter chillers.
• Dometic: versatile solutions for medium to large vessels, also suitable for retrofitting.
• Calpeda: robust and reliable pumps, ideal for custom installations or long pipe runs.

Technical Note on Glycol Circuit Maintenance

One often overlooked aspect is the importance of cleaning the glycol circuit to:

• Keep the chiller's heat exchanger clean.
• Prevent premature wear of pump seals.
• Ensure long life of all circuit components.

Manufacturers recommend replacing pump seals at least once a year to avoid leaks and maintain system reliability. A seal leak can cause the glycol circuit to empty, leading to system shutdown. Moreover, replenishing with fresh water dilutes the glycol mixture, decreasing its protective properties against corrosion and biological growth. For this reason, installing pre-filters and magnetic dirt separators is advisable...

Technical Diagram