Recent research activities related to heat transfer comprise different directions. For example, an analytic model for the effective thermal conductivity of heterogeneous systems such as nanofluids has been developed and undergoes further refinements. In addition, current efforts aim at checking the feasibility of the promotion of dropwise condensation of working fluids with low surface tension by suitable surface modifications. Last but not least, heat transfer modelling activities for different applications such as mixture condensation of natural refrigerants on tubes as well as processes where contact resistances between solids are important are in preparation.