In the present work, a new model built through refinement of the existing residence time distribution model [Foss, PhD Thesis, University of Delaware, 1957] is proposed. In this new model, the tray is imaginarily partitioned into compartments along the liquid flow direction between inlet and outlet. This partitioning allows computing the tray efficiency through quantification of the efficiencies of the individual compartments. Therefore, the fluid dynamics of each compartment contribute towards the evolving tray efficiency, thereby breaking the tray's black-box convention. The tray segmentation further supports in studying the effects of vapor maldistribution as well as flow path length on the tray efficiency. This indicates the versatility and advantage of the new model over the existing ones. In particular, the mathematical formulation of this model along with its theoretical validation and application through analysis of suitable case studies are presented.