A model for vapor transport with condensation and evaporation on a solid-air interface is set up. It consists of a convection-diffusion equation describing vapor transport, an ordinary equation describing condensation and a Stefan-type equation on with convection describing energy transport. The proof of existence of a solution is based on a method used by J.F. Rodriguez in several publications on the convective Stefan problem. The new part in this system is a lower-dimensional Stefan problem on the air-solid interface that describes possible freezing of the condensed water. TheModel described in this article could also be applied to crystalization problems
