Waste Heat Recovery for Ships

Waste heat recovery is a growing field of research in internal combustion efficiency improvements. A conventional gasoline internal combustion engine converts about 30% of the energy in the fuel into mechanical work. With a efficient diesel, the figure is about 35%. The rest of the energy is lost in the form of waste heat, through the cooling system and the exhaust.

This is largely because of metallurgical limits of materials currently used in internal combustion engines. With no real alternatives in the near future, aluminium and iron are still the most viable materials for engine construction. A number of experiments were carried out using ceramics for engine construction. While theoretically ceramics can provide a higher efficiency in thermal combustion (due to the higher temperatures they can withstand), production engines using ceramics cannot be expected in the near future. So engineers are exploring ways to harness the energy wasted to the environment.

BMW and Honda have both tried experiments with Rankine cycle units that can provide additional electricity, reducing the load on the alternator and improving the fuel efficiency a bit. Systems like those are however too expensive for automotive use. A better fit would be use in applications where initial cost is a smaller fraction of the high-running costs--applications such as ships, for instance. Opcon, a Swedish energy and environmental technology group is now about to install a waste recovery system on a Wallenius ship. The pilot installation will potentially save about 4 to 6% of fuel. Wallenius's statistics show that the company uses about 200,000 to 250,000 tons of bunker fuel a year for their fleet of over 150 vessels.

Wallenius is interested in both the fuel savings and the environmental credit that comes with lesser carbon and sulphur dioxide emissions. "The opportunities that Opcon Powerbox offers for utilising waste heat and reducing fuel consumption on board our ships are among the most interesting we have seen in this field. A fuel saving of between four and six per cent is considerable in this context. In future we see opportunities to use this technology and make savings of up to ten per cent. We aim to install Opcon Powerbox on all of our new vessels and on most of our existing ones in future. We want to be among the leaders in the shipping sector in reducing energy consumption and cutting emissions," says Per Croner, CEO of Wallenius Marine AB.

Opcon's Powerbox runs on the organic rankine cycle (similar to Honda's and BMW's) and uses waste heat to vaporise a working fluid that then expands in a screw type compressor. The Lysholm screw compressor is connected to a generator that will produce electricity. After passing through the screw compressor, the fluid is cooled and pumped back to continue the cycle. Maximum efficiency and hence electricity generation is governed by the difference in temperature between the hot and cold side.


Niklas Johansson

Vice President - Investor Relations

Opcon AB

Box 15085, 104 65 Stockholm


Phone: +46-70-592-54-53

Email: info@Opcon.se

URL: www.Opcon.se

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