Skip to main content



Monday, September 27, 2021 

Danish company Desmi says that its intelligent power management system for cooling pumps and fans, known as OptiSave, can help compliance with the maritime industry's ever stricter regulations for reducing CO2 and greenhouse gas emissions, including the long-term Energy Efficiency Existing Ship Index (EEXI) and the Energy Efficiency Design Index (EEDI).

The measures require all ships to calculate their EEXI following technical means to improve their energy efficiency and to establish their annual operational carbon intensity indicator (CII) and CII rating. Carbon intensity links the greenhouse gas emissions to the amount of cargo carried over distance travelled.

Desmi says that ship owners can implement several technologies to meet the requirements. One of these includes Energy Efficient Technologies, which focus on improvement of fuel consumption in auxiliary engines. The OptiSave Energy Saving System is believed to offer a cost-effective solution for compliance. The systems can be integrated at the new build stage or as retrofit applications, fully integrated within the overall control systems. The OptiSave system is suitable for vessels that will continue to be in service beyond 2030.

"You should install it regardless of the rules and regulations,” said John Nielsen, Desmi Key Account Manager of Marine and Offshore. “At the end of the day, you want to save fuel. And in doing so you help save the planet.”

Sea cooling water systems and pumps are designed for operation in 32°C seawater and 100% engine load. Normally, they run as if this condition is permanent, all over the world. But actually, there are only a few hot spots where these conditions are present. Otherwise, it is usually lower or much lower. A standard vessel cooling system operating in these conditions will be absorbing too much energy 95% of the time. The OptiSave system can regulate the energy consumption according to the actual cooling demand – thereby saving fuel as well.

OptiSave improves the efficiency of the sea cooling water pumps, depending on the sea water inlet temperature and the overboard sea water temperature. Using the OptiSave system allows for an increase in the overboard temperature, increasing the heat exchange capacity, and cooling capacity, making it possible to reduce the power consumption to a minimum.

Desmi also offers an OptiSave system for Low Temperature Fresh Water (LT/FW) cooling where the control is formed by using pressure, temperature, and flow measurements to obtain the lowest possible energy consumption on the main LT/FW pumps. OptiSave designed to work with the temperature requirements set forward by MAN and by WinGD.

Additionally, OptiSave can be set to work in a similar way for the ventilation system in the engine room. Each fan has its own individually mounted frequency converter and a common control PLC for fan speed/air-flow regulation.

Reader Comments (0)

There are currently no comments on this article. Why not be the first and leave your thoughts below.

Leave Your Comment

Please keep your comment on topic, any inappropriate comments may be removed.

Return to index