The thesis examined the installation and energy efficiency of a retrofitted Alaska Cooling -system on a passenger ferry.

The research was able to find out how much the new system can reduce the vessel's energy consumption and reduce costs on an annual basis. The goal was also to make the ship more environmentally friendly and to meet the new requirements.

Analyzing the vessel’s accounting for fuel consumption to calculate the system payback time and the required energy needed in an air conditioning system was used as a research method for the thesis. Technical drawings from the vessel and equipment manufacturer were used as research material.

By calculating the energy consumption onboard, it was possible to verify that the system is profitable. The payback period was obtained by calculating how much reducing the use of air conditioning compressors saves fuel on energy production and comparing the results with the total costs of the system.

Installation of the system was found to be a successful solution to reduce energy consumption on the vessel and a profitable investment even for an old ship due to the fast payback period.