  A theory of thermal transport in a two-channel Kondo system, such as the one
formed by a small quantum dot coupled to two leads and to a larger dot, is
formulated. The interplay of the two screening constants allows an exploration
of the Fermi liquid and non-Fermi liquid regimes. By using analytical, as well
as numerical renormalization group methods, we study the temperature dependence
of the thermal conductance and the Lorentz number. We find that in the low
temperature limit, the Lorentz number attains its universal value, irrespective
of the nature of the ground state.
