Development of a Passive Cooling System for a Gearless Wind Energy Generator

Today, the gearless horizontal axis wind turbines are mainstream in wind energy industry. High demands of electric power leads to bigger systems and active cooling reduces the overall efficiency of the turbines. Passive cooling systems have been examined for the first time for a gearless wind energy generator with a power range of 3-12 MW. With the further developed heat conductors, it is possible to operate a wind generator in a larger power class with passive cooling components. This is accompanied by enormous cost savings due to the elimination of costs for active cooling elements such as the use of fans, pumps, and heat exchangers. An additional factor is the significant reduction in necessary maintenance due to the minimized incidence of corrosion and wear. Design of the cooling fins and an optimized position of the generator within the housing of the wind turbine has been objectives. Mandatory was that maximum temperature of the generator fins should stay under 155 degrees C, which could be reached with several designs for different heat exchanger geometries.