Sea Zero: HVAC enabling zero-emission sailing

After 3 years of research and development, the final design concept confirmed a total energy reduction of 44% compared to existing Hurtigruten vessel MS Trollfjord. Our contribution, in close collaboration with SINTEF Energy, VARD and Hurtigruten, showed that the hotel systems account for around half of these savings. Making energy-efficient hotel systems a key enabler for zero-emission sailing.

A key challenge addressed in the project is the transition to battery-powered vessels, where surplus heat from conventional combustion engines is no longer available. Heat was no longer a by-product from the propulsion system, but a very limited resource. This has required new approaches to heating and ventilation, combining heat pump technology with advanced demand-controlled systems to ensure both energy efficiency and passenger comfort.

Through the Sea Zero project, we have worked with a holistic approach to energy use, focusing on production, distribution and reduction of heat demand. By integrating efficient heat production through heat pumps, optimizing energy distribution, and minimizing unnecessary consumption, substantial savings have been achieved without compromising onboard comfort.

Key aspects have included further development and integration of our Thermal Energy Management System with all available low-temperature heat sources onboard. A conceptual shift, where cooling demands are viewed as potential heat sources, has shown that traditional free cooling with seawater becomes less relevant, as all available energy must be utilized. 

Furthermore, the optimization of demand-controlled ventilation systems, providing comfort on demand, has proven critical in avoiding unnecessary energy use for the transport and treatment of excess outdoor air. Through pilot testing onboard MS Trollfjord, we optimized our Smart Cabin solution, featuring individual temperature control, integration with the booking system, and fully automatic presence detection. 

This holistic approach has also highlighted the importance of early-phase system integration. By involving HVAC and hotel systems at an early stage of the design process, with real influence on vessel design, it has been possible to unlock synergies that would not be possible through isolated system improvements. The results demonstrate that energy efficiency must be embedded as a core design parameter from the outset to enable zero-emission operation. 

The findings from the Sea Zero project underline that energy efficiency is not only a supporting element, but a fundamental enabler of zero-emission shipping. While the concept has been developed for a new generation of vessels, many of the technologies and principles applied, including demand-controlled ventilation, heat pump integration and optimized energy management, also hold significant potential for retrofit in existing fleets. As the industry transitions towards alternative energy carriers with higher cost levels, reducing energy demand will become increasingly critical. The solutions developed through this project demonstrate that significant gains are already within reach, both for future vessels and for ships in operation today.