This report documents the work of reducing the power consumption of the cooling system aboard a cargo ship from A.P. Møller-Mærsk. The cooling system was rst analysed, and based on the analysis a model of the system was created. Based on current design specications, a requirement specication was stated. A classical control scheme was developed and veried using the model. This control scheme proved, that it was possible to reduce the power consumption by 79.3% and 97.8% during two specied voyages. In order to further improve the reduction in power consumption, an advanced control scheme was developed and implemented on the model. The tests carried out using this scheme proved, that it was possible to obtain a reduction of 92.5% during the rst voyage. The previous schemes were developed using the setup of the existing system. In order to further reduce the power consumption, the system was analysed with extra adjustable valves implemented. This alteration to the system proved, that the power consumption could be reduced further than by just implementing the advanced control scheme. This report proves, that it is possible to reduce the power consumption of the cooling system aboard a cargo ship from A.P. Møller- Mærsk. Because of the results of this report it has been estimated, that implementing the advanced control scheme, would be the most protable solution. This is because it resulted in the highest power reduction, with the lowest implementation eorts.