Novel and highly compact design concepts for the desorber and rectifier components are presented to facilitate development of small capacity ammonia-water absorption systems for a wide range of applications. These designs enable thermodynamically optimal diabatic distillation and can be applied for direct coupled waste heat recovery applications or for indirect heat source coupling. A hydrodynamic design methodology is developed and applied to address liquid-vapor countercurrent flow limitations. Feasibility of these designs is validated through air-liquid flow visualization experiments that simulate target flow patterns. The effects of geometric parameters and fluid properties are investigated to specify internal component features and dimensions. Parameters for coupled heat and mass transfer modeling of these designs are identified and quantified through high-speed video analysis. The results of this study guide the design and further development of highly compact and efficient desorption components for optimal thermal compressors. (C) 2018 Elsevier Ltd. All rights reserved.