Advanced engineering provides compact waste heat recovery for the marine sector

The development of a new waste heat recovery system could not only deliver fuel savings of up to 8% for ship owners and operators but also transform environmental standards in the marine sector, says the firm behind it.

The concept features technology engineered to reduce emissions and vessel operating costs by converting waste heat from the vessel engine into electricity.

The two-year £3.6m project is funded by the Energy Technologies Institute (ETI), and is being led by AVID Technology, a firm that develops powertrains for high performance electric vehicles, with assistance from Royston Power and France’s Enogia SAS. North East-based RED Engineering is assisting with marine regulations compliance.

At the heart of the waste recovery system is equipment that uses the Organic Rankine Cycle (ORC) heat transfer process and a turbo generator power conversion system to convert thermal energy from the engine jacket water into electricity. Specifically, an environmentally safe refrigerant is boiled with waste heat. This refrigerant steam is then used to drive a turbine which in turn powers a generator. The refrigerant is then cooled and pumped back around the system.

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Circuit diagram.

Electronics provides compact packaging of heat recovery technology
This heat recovery technology is available already but what is new, according to RED Engineering’s managing director Joe Orrell, is AVID’s high-power density generator and electronics, which have been redesigned and packaged into a system that is much smaller in volume than traditional ORC systems.

Joe Orrell says the project demonstrates the efficiency savings that are achievable using advanced engineering solutions: “This draws on technology and expertise developed for the automotive industry, taking costs out and increasing durability. The result is a system with a lower cost per installed kw than anything on the market in a package size that meets the tight constraints of imposed by marine applications.”

AVID’s founder and managing director, Ryan Maughan, adds that the smaller volume of the package when compared to traditional ORC systems offers significant advantages. “The ORC system is very compact and can therefore be accommodated into a much wider range of vessels,” he says. “The whole system can fit into a vessel engine room as a retrospective installation, which gives some indication of its size, flexibility and impact on vessel layouts.”

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The system uses a compact design

Modular design suits retrofit
The system is being designed to be modular in an approach that meets the demands of the retrofit market. This will allow it to be easily broken down and transported through tight hatches and access doors, although Ryan Maughan points out that “re-assembling and installing inside the vessel is bound to throw up some interesting challenges to overcome” as the project moves towards completion.

The projected 8% fuel saving comes from a market study completed by the ETI but multiple systems can be connected to generate more power which in turn, would generate a fuel saving that is dependent on how many systems are installed versus on-board engine power.

RED Engineering’s role is to make sure that the equipment developed complies with the appropriate marine regulations: SOLAS requirements and the class regulation of DNV GL. This involves leveraging its expertise in safety critical marine systems’ engineering and working on the documentation and design rules, which will allow the technology to progress beyond the concept to the application stage.

The firm’s engineers are also providing technical input to support the installation of a demonstration unit in 2018, while Royston is involved in working with the vessel operator to undertake installation ahead of in-vessel testing and commissioning. Enogia is responsible for the design of the ORC turbine.

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Turbine generator assembly.

Markets
The system is being developed to ensure it meets the challenge of operating in harsh marine environments on all types of vessels. There’s considerable interest being shown from cruise ship operators, where the benefits of such technologies are apparent.

However, the opportunities are wider than that sector, which does not represent the bulk of global fleets, and so the first demonstration unit will not be installed on a cruise ship. Work is therefore underway on more traditional vessels to demonstrate the potential for the technology in the mass market of marine vessels.

Progress on the project from initiation to concept phases has been rapid. Qualification testing and approval of key components is underway alongside the design and development of the turbo generator, system packaging and design approval from DNV GL.

Ryan Maughan says: “The system is currently in a land-based development and testing phase and we are going through the design process necessary to make the technology marine-ready and obtain class approvals. While we anticipate challenges ahead in finalising the class approval before moving to installation in an actual vessel, we are confident about the long-term success and viability of a system that could deliver major cost savings for shipping owners and operators.”

Land-based testing of the marine specification system at full power is the next phase, which according to both RED Engineering and AVID, will herald another milestone for the programme.