This paper presents a simulation of a real steam generator from a coal-fired power plant using a network of heat exchangers. The proposed approach is a combination of the Heat Exchanger Network method with the least squares method to represent the overall heat transfer coefficient as a linear function, which depends only of the flue gas flow, aiming to calculate the temperatures in between the heat exchangers in different operations situations. The data base used is a heat and mass balance provided by the partner enterprise. Steady state and one dimensional flow were considered. The result obtained by the Heat Exchanger Network method was limited by the approximation quality of the overall heat transfer coefficient and the heat transfer area product, obtaining a relative error in the order of 5 % for most values and reaching an error of 18 % in the worst case.