  We consider the thermoelectric properties of a double-quantum-dot molecule
coupled in parallel to metal electrodes with a magnetic flux threading the
ring. By means of the Sommerfeld expansion we obtain analytical expressions for
the electric and thermal conductances, thermopower and figure of merit for
arbitrary values of the magnetic flux. We neglect electronic correlations. The
Fano antiresonances in transmission demand that terms usually discarded in the
Sommerfeld expansion are taken into account. We also explore the behavior of
the Lorenz ratio L=\kappa/\sigma T, where \kappa\ and \sigma\ are the thermal
and electrical conductances and T the absolute temperature, and we discuss the
reasons why the Wiedemann-Franz law fails in presence of Fano antiresonances.
