IntEgrated reversible CO2 heat pump to sail towards actual zero-emission ferries

Ferries are responsible for 0.8 million tons of greenhouse gas emission annually in Denmark and often sail close to cities where they add to the already critical air pollution levels. This holds especially true for small Danish municipalities, as diesel-driven ferries contribute up to 20 % to their total global warming contribution. Therefore, fully electric powered ferries are taking centre stage in Denmark. However, the current wide use of synthetic refrigerants (and their leaks into the atmosphere) in the maritime sector leads even 100 % electricity-powered ships not to be actually greenhouse gas emission free. In addition, currently the driving range of fully electric powered ferries is penalized due to the lack of an optimized heat pump system layout, suitable battery thermal management strategy and appropriate waste heat recovery approaches.
The objective of the ECO2-ferries project is to develop the first heat pump being completely tailored to 100 % electricity-powered ferries. The use of CO2 as a natural (i.e. future-proof) refrigerant of the heat pump will finally lead 100 % electricity-powered ferries to be actually greenhouse gas emission free ships. In addition, CO2 will allow for a compact heat pump and high safety levels (i.e. non-flammable and non-toxic). High energy performance will be guaranteed by the implementation of (i) an optimized system layout, (ii) a proper battery thermal management approach, (iii) a suitable heat recovery technique as well as (iv) an effective and robust overall control strategy.

The ECO2-ferries project will involve the University of Southern Denmark, Odense Maritime Technology and Marstal Navigationsskole as project partners and Danske Maritime, Danfoss A/S, BCOOL A/S, Danish Technological Institute, Ærø municipality and Ærøfærgerne as project supporters. The project has received funding from Den Danske Maritime Fond.