Waste Heat Recovery technology for ships; potential for 5–10% fuel savings

The Opcon systems generate electricity from low-value waste heat in the vessel’s steam and cooling system. The aim is to save fuel while reducing emissions of CO₂, NO_x, sulfur and particles. For this first reference installation aboard the Large Car-Truck Carrier (LCTC) MV Figaro, IMO 9505041, fuel savings are expected to be around 4-6%, but the potential in other installations is 5-10%, according to Opcon.

Opcon Powerbox ORC Marine version. Click to enlarge.

The 227.8-meter (747-foot), 74,258 gross tonnage Figaro, bult by Daewoo Shipbuilding & Marine Engineering, can carry 7,879 cars or a combination of 3,508 cars and 432 buses. The main engine is a two-stroke MAN B&W 8S60ME-C8 electronically controlled directly reversible marine diesel with constant pressure supercharging and a maximum output of 19,040 kW (25,533 hp) at 105 rpm.

In a separate compartment of the engine room there are two 450 V, 60 Hz, 1,700 kW AC-generators installed each powered by a STX/MAN-B&W diesel engine, type 9SL21/31H. In addition the vessel is equipped with a 1,100 kW shaft generator and an emergency diesel generator with a capacity of 215 kW.

Behind this success lies some enormous hard work carried out to integrate these systems. This is a milestone in our efforts to adapt our pioneering technology for production of electricity from waste heat for use in marine applications. We will now fine-tune, test and verify the improvement in energy efficiency that this system offers in various operational scenarios at sea. By utilizing waste heat and recovering the energy, significant environmental gains can be made. Considering today’s oil prices and the efforts being made by the IMO, for example with the coming International Energy Efficiency Certificate (IEE), we believe that this product really has come at exactly the right time.

—Rolf Hasselström, President and CEO of Opcon AB

Opcon has developed two marine versions of its Powerbox:

• Opcon Powerbox ORC (Organic Rankine Cycle), which enables utilization of low-value heat such as hot water in a vessel’s cooling system. Waste heat is used by a heat exchanger to vaporize a working fluid with a boiling point lower than water. The gas expands over an expander, which drives a generator to produce electricity. The fluid is then cooled, and a pump increases its pressure to 30 bar, and circulates it back through the first heat exchanger.

  The unit comprises a Lysholm turbine with a synchronous generator and auxiliary systems. The key factor in the ORC system is the reliable Lysholm turbine, developed by Opcon’s Svenska Rotor Maskiner (SRM