Aim To study the method of establishing the mathematical models with high accuracy and wide range. Methods Considering the actual conditions of intelligent instrument to test heating power parameters
the paper ascertains the temperature and pressure variables for mathematical models. According to the international standard thermodynamic data
the coefficients of these models are derived by using multiple regression. Results The accuracy of models is tested and verified
and the rightness is proved by experiments. Conclusion These models present a feasible way to design intelligent instrument of measuring heating power parameters. The models can apply to any calculation of heating engineering.