Alfa Laval is introducing the ‘Hukka-5’, a next-generation exhaust gas steam boiler designed to enhance waste heat recovery on cruise vessels and passenger ferries.
Its inverted, downward natural circulation design enables efficient recovery of exhaust gas waste heat while minimising equipment footprint. By capturing and reusing exhaust gas waste heat, the innovative boiler helps operators significantly reduce fuel consumption and CO₂ emissions, supporting both environmental targets and operational efficiency.
For cruise vessels and passenger ferries, improving energy efficiency increasingly means making better use of the energy already available onboard. Hukka-5 addresses this by enabling greater waste heat recovery from exhaust gases in a compact boiler configuration, helping operators make more efficient use of onboard energy. The new boiler is available immediately for project orders.
According to Alfa-Laval, natural circulation has become the industry standard for exhaust gas steam boilers on cruise vessels, eliminating the need for circulation pumps by harnessing physical principles to move water through the boiler unit. With Hukka-5, Alfa Laval takes this technology further by introducing downward natural circulation. The design enables counter-current flow conditions, even within the limited space of ship funnels, resulting in a minimised exhaust gas boiler (EGB) footprint. This minimises the risk of flow instabilities in the evaporative circuits, even with exhaust gas temperature fluctuations which could be the case when using alternative fuels.
The result is a waste heat recovery solution designed to deliver optimal operational performance, enhanced safety and advanced energy efficiency on vessels with four-stroke engines, especially those with frequent port calls, such as cruise ships and passenger ferries.
Matti Takasuo, GM BD and Sales for Power, Offshore and Cruise business line, Alfa Laval, said: “Our previous state-of-the-art WHR boiler, Aalborg XWi, set the standard for natural circulation on cruise vessels. Now, as the need for greater waste heat recovery grows, we are introducing the Hukka-5 and taking energy efficiency to the next level. Since every square meter matter on cruise ships, the new innovative inverted natural circulation design recovers more waste heat without increasing the footprint.“
Hukka-5 is part of the Hukka exhaust gas steam boiler product range, together with Hukka-8. The range is compatible with engines and gas turbines running on all fuels, including methanol and hydrogen. The Hukka-5 is designed to adapt to the operational needs of cruise vessels and passenger ferries. It offers seamless integration of electrical steam generation, without the need for additional pressure vessels or auxiliary/fired boilers, enabling efficient steam production during port stays when shore power is available. Additionally, the boiler’s modular design enables tailored configurations, including selectable multi-stage heat recovery solutions with optional condensing cold-end design, further improving installation’s energy efficiency.
Beyond energy savings, the modular approach is intended to reduce costs, shorten lead times, and lower the specific carbon footprint during construction. Hukka-5 is equipped with a vertical steam drum as a standard, for optimal layout design, free of ship orientation installation requirements.
By capturing and reusing exhaust gas waste heat, the Hukka-5 enables cruise vessels and ferries to maximise energy utilisation and minimise environmental impact. The design enables the possibility to recover more energy from exhaust gases, reducing the need for additional fuel and lowering overall CO₂ emissions. This not only supports compliance with increasingly stringent maritime regulations but also helps operators achieve their sustainability targets and lower operating costs.
Image: Hukka-5 exhaust gas boiler (source: Alfa-Laval)
