Thermal Management Optimization Study Of Hydrogen Fuel Cell System For Marine Hybrid System

The shipping industry is the basis of international trade and ships are the main means of transport for international logistics,while diesel engines are still predominant in the current ship propulsion market.With environmental pollution and energy scarcity becoming increasingly serious,the International Maritime Organization has proposed strict regulations on maritime emissions.Using clean energy sources such as hydrogen to replace diesel can significantly improve the SOx and NOx emission targets of ship engines.Proton exchange membrane fuel cells(hydrogen fuel cells),which use hydrogen as the main fuel,have the advantages of zero emissions,low noise and high energy efficiency conversion rate,and have broad application prospects in the marine sector.However,fuel cells require high operating temperature,low temperature will lead to cold start failure,high temperature will cause damage to the proton exchange membrane,especially in marine applications,in order to meet the high power requirements of the ship,hundreds of single cells need to be combined,the large size of the stack leads to its more difficult to dissipate heat,will have an impact on the performance and life of the battery,so the thermal management system is more demanding.In order to improve the thermal performance of the battery thermal management system,the following work has been done in this paper to study the fuel cell stack model and thermal management system model.In this paper,firstly,based on the operating principle of proton exchange membrane fuel cells,a fuel cell stack model was constructed using gFUELCELL software and calibrated with data from a 30 kW low power stack.The single cells were then combined for the power requirements of marine applications,resulting in a 110 kW high-power stack model,and the laws of proton exchange membrane thickness,air humidity,cooling water flow and air excess coefficient on the fuel cell output characteristics were analyzed.The overall fuel cell thermal management system scheme was then designed,and the fuel cell thermal management system was modelled using GT-Suite software and calibrated by a 30 kW thermal management system,and the effects of ambient temperature,pump speed and fan speed on the cooling effect of the fuel cell system were compared and analyzed.Then,based on the 110 kW fuel cell of the marine high-power hybrid system,the heat sink of the thermal management system was improved for the actual situation through thermal value analysis and system design requirements,the selection of fuel cell thermal management system components was completed,and the influence of the rotation speed of the fresh water pump and the sea water pump on its cooling effect was analyzed.Finally,the design of experiments(DoE)method was used to optimize the fuel cell at 100%,75% and 50% of the rated operating conditions respectively,and a DoE optimization model was established.The final strategies for matching the speed of the freshwater and seawater pumps to meet the minimum total power consumption of 0.573 kW,0.338 kW and 0.172 kW respectively for each operating condition and to meet the operating temperature of the reactor.