Using the forward movement of a container ship navigating in the Arctic to air-cool a marine organic Rankine cycle unit

摘要

Ice coverage in the Arctic is declining, allowing for new shipping routes. Navigating Rotterdam-Yokohama through the Arctic instead of going through the Suez Canal reduces the travel distance by about 60% thus potentially reducing fuel consumption, CO2 emissions and other pollution factors. It is important to reduce the environmental impact further in the sensitive Artic, and this can be done with a waste heat recovery system (WHRS). Low heat sink temperatures increase the WHRS thermal efficiency substantially and the cold Arctic air presents an attractive opportunity at the cost of increased power consumption due to air moving through the condenser. This paper investigates the exploitation of the forward movement of a container ship navigating in the Arctic Circle and density-change induced flow as means of moving air through the condenser in an organic Rankine cycle (ORC) unit to reduce the fan power required. The ORC unit uses the available waste heat in the scavenge air system to produce electric power. The paper uses a two-step optimisation method with the objective of minimising the ship's annual CO2 emissions. The results suggest that using the supportive cooling could reduce the fan power by up to 60%, depending on the ambient air temperature.