In this article a method for calculating the radiation of plates in a thermoviscous fluid is presented. It is an extension of the plate mode expansion method used for ideal fluids to the case where thermoviscous effects are included. The model is comprehensive in the sense that it addresses all the key factors associated with thermoviscous phenomena and therefore, no simplifying assumptions are made. The influence of compressibility, inertia, viscosity, thermal conductivity and, in particular, the second coefficient of viscosity is considered. In the first part, the model is realized for an infinite plane and in the second, the model is extended towards finite simply supported plates. At the end of these mentioned sections, numerical results are provided for particular cases.