  Thermal and charge transport in the diffusive normal metal(DN) / insulator /
$s$-, $d$- and p-wave superconductor junctions are studied for various
situations, where we have used the Usadel equation with Nazarov's generalized
boundary condition. Thermal and electrical conductance of the junction and the
Lorentz ratio are calculated by varying the magnitudes of the resistance, the
Thouless energy and the magnetic scattering rate in DN, the transparency of the
insulating barrier, and the angle between the normal to the interface and the
crystal axis of d-wave superconductors or the angle between the normal to the
interface and the lobe direction of the p-wave pair potential. New general
expression is derived for the calculation of the thermal conductance. It is
demonstrated that the proximity effect doesn't influence the thermal
conductance while the mid gap Andreev resonant states suppress it. We have also
discussed a possibility of distinguishing pairing symmetries based on the
dependencies of the electrical and thermal conductance on temperatures.
