Internally cooled horizontal tube banks are widely used as absorbers in thermally driven heat pumps. Recent visualization studies have revealed several flow structures such as formation, detachment, and impact of droplets, and the resulting waves and film disturbances, which can affect the liquid mixing and distribution, and consequently affect the heat and mass transfer rates. A hydrodynamic model of flow over microchannel tube banks that addresses these flow structures is presented in this paper. Droplet mode flow is modeled by considering representative primary droplets, evolving at specific droplet formation sites on each tube row. The spreading of liquid over the tube surface is modeled by considering three regions: the Feed region, the Spread region, and the Inactive region. Various droplet and film characteristics, such as droplet spacing and evolution time, film thickness and spreading, and tube wetting are also addressed. This hydrodynamic model can be coupled with a corresponding heat and mass transfer model to estimate the local absorption rates in the flow. (C) 2018 Published by Elsevier Ltd.