2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/99393Site energy of the five-state ferromagnetic Potts model is numerically calculated at the first-order transition temperature using corner transfer matrix renormalization group (CTMRG) method. The calculated energy of the disordered phase $U^{+}$ is clearly different from that of the ordered phase $U^{-}$. The obtained latent heat $L = U^{-} - U^{+}$ is 0.027, which quantitatively agrees with the exact solution.2 pages, Latex(JPSJ style files are included), 2 ps figures, submitted to J. Phys. Soc. Jpn.(short note)Statistical Mechanicstext