This paper presents a detailed investigation on the volumetric transfer coefficient (VHTC) model in solid-fluid porous media based on the Volume averaging method (VAM). The VHTC is obtained by solving the closure problem with the control-volume finite difference method. A thermal analysis is conducted to illustrate the thermal nature of the VHTC, based on which, an improved VHTC model has been proposed by taking into account the effects of the thermal entrance and the non-uniformity of the velocity field. With this model, the applicability of the VAM has been extended to large Peclet number laminar regime for convection heat transfer in porous media characterized by straight ducts.