Mitsubishi Heavy Industries Marine Machinery & Equipment Co (MHI-MME) and Wärtsilä have signed a memorandum of understanding (MOU) to create a new energy solution that produces greater power generation capacity and higher propeller propulsion for marine vessels.
By integrating MHI-MME’s waste heat recovery and energy-saving power generation system (WHRS) with Wärtsilä’s operational control technology for shaft generator systems, the new solution has been designed to result in more energy-efficient ship navigation and an improved energy efficiency design index (EEDI).
According to a statement released by both companies, a “notable innovation is the combining of a power take-off/take-in (PTO/PTI) shaft generator system with WHRS to improve the stability of the WHRS”. Depending on the load of the main engine and the ship’s network, the WHRS sometimes produces electrical energy in excess of that needed by the network. Such energy can be utilised via the PTO/PTI generator to drive the propeller shaft.
At full load, the surplus energy can be used to assist the ship’s drive by being applied directly to the propeller shaft. At low main engine load, the WHRS can be operated in parallel with a diesel generator set. Parallel operation with a shaft generator via PTO operation is also said to be easily implemented.
The patented design connects the WHRS generator into the DC link circuit of the PTO/PTI shaft generator rather than directly into the mains. This allows operation of the WHRS at reduced speed to create higher efficiency of the turbine system at part load. In so doing, it avoids the necessity of speed regulation valves, which cause throttle or bypass losses.
“We are moving forward various energy-saving technologies and can expand our portfolio with this new solution, which we are quite convinced will satisfy present market demands for increasing environmental awareness,” said Tomoo Kuzu, executive vice president of MHI-MME. “We wish to thank Wärtsilä for its high-quality collaboration that has made it possible.”
- January 2018