The numerical conduction of heat in packed beds of particles is investigated, including the effects of inter-particle microasperity gaps and deformation contacts. A detailed numerical model of two half spheres in contact with interstitial fluid is constructed, including asperity (roughness) gaps and deformation contacts on the respective orders of 5 mu m and 100 mu m for 1 mm particle diameters. The resulting heat flux distributions at the diametrical planes of the particles are integrated to yield the overall thermal conductance, K, or resistance, R = 1/K, between the two diametrical planes. The results show K to be strongly dependent on the interstitial fluid gap and the deformation contact diameter, as well as on fluid and solid conductivities. The effective bed conductivity, k(e), is determined as a function of K and the void fraction, and correlated in terms of bed parameters. The resulting k(e) correlation agrees well with published experimental data over a wide range of substances and temperatures.