In this contribution, a simplified macroscopic and semi-analytical thermal analysis of directed energy deposition (DED) is presented to obtain computationally efficient simulations of the entire process. Solidification and solid-state phase transitions are taken into account. The model is derived for laser metal powder directed energy deposition, although it can be simply adapted for other focused thermal energy (e.g., electron beam, or plasma arc). The gas flow used for carrying the powder significantly influences cooling conditions, which is included in the model. The proposed simulation strategy applies to multilayer composites with a wide range of shapes in the horizontal plane and arbitrary laser scanning strategies (continuous way, back and forth, etc.). The proposed work provides a simple tool to study the influence of most process parameters, design in-situ experiments and in turn develop optimization loops to reach material requirements and specific microstructures. In-situ pyrometer measurements have been compared to the model, and good agreement has been observed with 2.6% error in average. The model is used to demonstrate the effect of various process parameters for a simple cylindrical geometry and a more complex auxetic cell.