Thermal analysis of wind turbine nacelle of 2.5 MW turbines at winter conditions

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A numerical method for analysing and quantifying the thermal behaviour of wind turbine nacelle of 2.5 MW operating in the extreme winter conditions have been presented. The effects of the extreme external temperatures of -30oC, -20 C and -10oC on the electrical equipment and mechanical components within the nacelle have been determined at the design wind speed of 12 m/s. Two cases, open and closed system applications, have been considered. For both cases without the AC at Text=-30oC,the surface temperatures of the gear box and generator are outside the temperature limits. When applying the AC to the systems, temperatures became inside the operation temperature limits. For closed system applications at Text=-30 oC and -20 oC, the surface temperatures of all components are inside the temperature limits with the capacities of the AC system, 5 kg/s at 0 oC, 5 kg/s at 10oC with some icing problems inside wall of the nacelle. For closed system applications at Text=-10oC, the surface temperatures of components are inside the temperature limits with the AC capacities of 4 kg/s at 30oC, 5 kg/s at 0oC, 5 kg/s at 5oC and 5 kg/s at 10oC without icing problems. The simulation results have confirmed that, to maintain an acceptable temperature levels inside the nacelle and on the components for typical winter conditions, the air conditioning systems are needed. The air conditioning systems of the nacelle have to be optimized and adjusted properly as functions of wind turbines rated power, external wind velocity and temperatures.