In large cruise ships, ventilation typically accounts for about 30 percent of energy use – second only to propulsion. However, by implementing a demand-based ventilation system, for example, in galleys and cabins, this consumption can be reduced by a third. Since electricity on board is generated by fuel-burning combustion engines, this results in significant savings in both costs and carbon emissions.
“Based on our data, a retrofit demand-based ventilation system lowers fuel consumption by about 10 percent. A large liner can burn between 150 and 250 tonnes of fuel each day, making this very significant. The payback period for the investment is less than two years,” says Claes Fog Boelge, CEO of Hvacon, a Danish company specializing in HVAC systems for marine vessels.
“There is no way to gain bigger cost savings on a passenger ship. Except maybe for reducing cruise speed, which is not a realistic scenario.”
A large passenger vessel can have a dozen galleys and 1,500–2,000 cabins, all equipped with ventilation systems. Traditionally, the galley and cabin ventilation operate at full capacity around the clock without adjusting the load to varying situations. In contrast, demand-based systems, such as those installed by Hvacon and Halton, operate only as needed, automatically adjusting the volume and temperature of the air.
Exit wasting, enter comfort
“In galleys, smart hoods detect cocking activities with an infrared sensor to monitor the temperatures of cooking surfaces and the temperature of exhaust air. The smart hood adjusts the amount of extraction air through the hood to the actual cocking demand. We then utilize the data to automatically regulate the amount of exhaust and supply air,” Claes Fog Boelge explains.
The goal is to ensure the right amount of ventilation at all times, whether idling or during various cooking activities.
Cabin ventilation retrofits follow a similar principle. Instead of continuously operating at high power, the air supply is adjusted based on occupancy and thermal comfort. Occupancy detection delivers real-time data on whether passengers are in the cabin or elsewhere on the ship.
Balcony door sensors prevent unnecessary cooling when the door is open. This creates a more comfortable environment for passengers while optimizing energy use. When less energy is used in the cabins, the load can be moved to other areas like the dining rooms, for example.
According to Susanna Ahonen, Sales Team Manager at Halton, the demand for retrofit ventilation systems is booming. She recognizes two drivers behind the increased demand.
“In many ships, ventilation equipment is simply reaching the end of its lifecycle. Secondly, the green transition is proceeding quickly in the industry. Sustainable solutions are becoming more valued, and regulatory pressure from the International Maritime Organisation (IMO) and other institutions is increasing quickly,” Ahonen says.
The rules of the game are changing
The IMO’s Energy Efficiency Existing Ship Index (EEXI) measures ships’ carbon dioxide emissions per cargo capacity and distance traveled. If a ship does not meet the required EEXI, its owner must modify it to reduce emissions. Another IMO framework, the Carbon Intensity Indicator (CII), annually measures the fuel efficiency of ships that transport goods or passengers. The IMO’s ultimate goal is to achieve net-zero emissions across the industry by 2050.
Moreover, starting in 2024, the European Union expanded its Emission Trading System to include the shipping industry. Large ships arriving at EU ports must purchase emission allowances based on their carbon emissions. Another framework, called the FuelEU Maritime regulation, effective January 1, 2025, mandates vessels to reduce their greenhouse gas intensity. Non-compliance incurs penalties.
“Improving energy efficiency is crucial for adhering to the new rules and regulations. In practice, the most effective approach is to address the fuel-guzzling ventilation systems. This will ensure efficient and sustainable operations for years to come,” says Susanna Ahonen.
Hvacon is an international Danish company that specializes in turn-key HVAC systems and energy optimization. As of 2024, it had over 30 employees and a revenue of 27 million euros. Halton specializes in demanding indoor air solutions and is a market leader in the ventilation of galleys in cruise ships. The two companies have partnered in retrofit turn-key vessel ventilation systems since 2020.
Contact
Susanna Ahonen, Sales Team Manager, Halton
susanna.ahonen@halton.com
+358 40 777 8108
