Waste heat recovery system

For large vessels with a main propulsion machinery with a mechanical output of over 20MW, it is possible to get more than the standard 50% efficiency from your fuel. ABB's Waste Heat Recovery System (WHRS) is designed to recover much of the standard heat and friction energy losses. This means fuel efficiency improves, auxiliary engines can be used less and less CO2 will be released. 

 

How the Waste heat recovery system works

Recovery of waste heat begins in the exhaust boiler. WHRS' dual pressure exhaust gas boiler efficiently generates steam suitable for electricity generation. For optimum efficiency, it generates steam at high and low pressure. Both the high and low pressure steam flows are led through the ship's steam piping system to a condensing steam turbine, which is connected to a generator. The turbine converts the thermal steam energy into mechanical energy to run the generator connected to the propeller shaft.
How much energy can be recovered?

The recovered energy, which is typically around 10% of the main propulsion shaft’s power, is converted back for mechanical work. Energy recovered from the exhaust can also be recovered and fed back to the propeller shaft. When WHRS is used in combination with a shaft generator, even further savings can be gained by improving the main engine's loading conditions.

Pre-calculated payback time

The Waste Heat Recovery System can be optimized to meet a required level of efficiency and tailored for the specified propulsion plant. Together with an estimation of fuel cost and the vessel's operational profile, it is possible to pre-calculate the payback time for the system.

Economy of scale

As waste heat is only recovered when the engine is running over a certain power output, the system efficiency will be higher for vessels with a relatively stable operating profile, especially with high propulsion loads.

Highlights

Achieving improved fuel efficiency with waste heat recovery

Reducing fuel costs by increasing the energy output from combustion engines

ABB wins over $23 million marine orders for fourteen container ships

Waste heat recovery system will increase the power output of the container vessels by up to 4 percent

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