Energy use and energy efficiency in cruise ship hotel systems in a Nordic climate
August Brækken, Cecilia Gabrielii, Nataša Nord
Abstract
In light of climate change, the shipping industry is committed to reducing its greenhouse gas emissions. When transitioning from fossil fuels to low-carbon fuels, it is crucial to also reduce the ships' energy need. For cruise ships, the hotel system is a major energy consumer and the focus of this paper. This study aims to investigate the energy use of an existing fossil-fuelled cruise ship operating in a Nordic climate, and evaluate the effectiveness of various passive and active energy-saving measures. For this purpose, a dynamic energy model of the hotel system was developed in the building simulation tool IDA Indoor Climate and Energy (IDA ICE), including a customised weather file. Validation of the model was achieved through comparison with literature and some operational data from the actual cruise ship. Simulation results showed a total annual energy use of 55 MWh/passenger, with the hotel system accounting for 20%. The passive measures, such as increased insulation and improved windows, each resulted in less than a 1% reduction in the hotel's annual energy use. Larger energy savings were achieved by using heat pumps (38%), improved ventilation system (8–24%), and heating setback in port and during the night (5%). A hot water storage tank, charged with the engines' waste heat during sea operation, could reduce the use of auxiliary boilers, especially in port. A hot water tank of 600 m3 could cover 97% of the heating demand in port, thereby minimising the use of fuel-fired boilers.