DNV GL introduces new methodology for ship efficiency


DNV GL

DNV GL has introduced a new methodology for ship management to identify the sources of useful energy that are being wasted aboard ships.

COSSMOS software considers all components on-board a vessel and measures the 'exergy', the maximum useful energy from each component, to quantify energy losses from the hull, propulsion power train, machinery and electrical systems.

DNV GL strategic research and innovation director Rune Torhaug said: "We have revisited the basic and universal laws of thermodynamics to develop a methodology based on exergy."

An analysis of a waste heat recovery system with up to 70 components, carried out through the company's exergy-based methology, identified the true sources of useful energy losses, revealing a picture far from self-evident.

Senior researcher and project manager George Dimopoulos said: "Subsequent optimisation in DNV COSSMOS yielded an increase in fuel savings that halved the payback time of the system."

"True sources of losses were identified with greater accuracy than a traditional energy analysis."

DNV GL identified a 50% reduction in exergy losses by applying its process to the fuel pre-processing sub-system for the marine fuel cell on-board the offshore supply vessel Viking Lady.

An aframax tanker's main engine was analysed using operating data with COSSMOS modelling, the true sources of losses were identified with greater accuracy than a traditional energy analysis.

"In fact, the standard energy analysis failed to identify the turbocharger as being the second largest contributor to exergy loss," Dimopoulos added.


Image: Illustration of DNV GL's fuel efficiency methodology. Photo: courtesy of DNV GL AS.