  Weyl semimetals (WSM) are topologically protected three dimensional materials
whose low energy excitations are linearly dispersing massless Dirac fermions,
possessing a non-trivial Berry curvature. Using semi-classical Boltzmann
dynamics in the relaxation time approximation for a lattice model of time
reversal (TR) symmetry broken WSM, we compute both magnetic field dependent and
anomalous contributions to the Nernst coefficient. In addition to the magnetic
field dependent Nernst response, which is present in both Dirac and Weyl
semimetals, we show that, contrary to previous reports, the TR-broken WSM also
has an anomalous Nernst response due to a non-vanishing Berry curvature. We
also compute the thermal conductivities of a WSM in the Nernst (${\nabla T}
\perp \mathbf{B}$) and the longitudinal (${\nabla T} \parallel \mathbf{B}$)
set-up and confirm from our lattice model that in the parallel set-up, the
Wiedemann-Franz law is violated between the longitudinal thermal and electrical
conductivities due to chiral anomaly.
