A partitioned coupling approach for conjugate heat transfer applications is presented. The coupling scheme is based on the extension of the parallel algebraic domain composition method already validated in fluid-structure interactions problems for thermal coupling. The method alters the original Dirichlet-Neumann approach enforcing the boundary conditions over the subdomains through matrix operations. The algorithm is tested on two benchmark cases with conjugate heat transfer: flow over a heated cylinder and flow over a flat-plate. The results indicate good agreement with previous research and encourages its application for large-scale problems.