In this article, the effects of a wind tunnel on the MEXICO wind turbine experiment based on a generalized Actuator Disc model and the second law of thermodynamics are investigated. In this model, both Computational Fluid Dynamic (CFD) and a developed User Defined Function (UDF) code are used to simulate the wind turbine's performance in both wind tunnel and free stream modeling. Metrological variables such as ambient pressure and temperature, velocity, and specific humidity are considered to analyze the wind turbine's performance. The maximum relative exergy efficiency difference between the wind tunnel and free stream at the wind speed of 16 m s-1, is 7.01%. Also, pressure, temperature and relative humidity, which mainly are neglected in energy analysis, have a considerable effect on wind turbine performance in both wind tunnel and the free stream conditions. It is shown that the combination of the actuator disc and the second law of thermodynamics provides a better insight compared with the first law analysis; therefore, it provides an appropriate approach for wind power simulation. (C) 2020 Elsevier Ltd. All rights reserved.