Integration of light well through generative design to achieve optimal day lighting and natural ventilation: The Case of Deep Plan Buildings in Old Town Pondicherry

A case of urban densification in heritage towns like Pondicherry has led to deep-plan wall to wall layouts, where the depth of the plot is considerably more than its width and multi-storey buildings with limited access to day light and natural ventilation. With the recent multi-storeyed developments, passive strategies are essential for achieving thermal and visual comfort. This study investigates the integration of light wells as passive systems to enhance day lighting and natural ventilation to improve indoor environmental quality for a deep plan building in such contexts. In the case of heritage town of Pondicherry, a typical base case sample deep plan residential plot of size 6m width and 20m depth with stilt with three storeys building of 14.4m height, was modelled using Rhino 7, and analysed using Grasshopper, Ladybug tools 1.5.0, Honeybee Radiance, and Design Builder 7.3.100.3 Evolutionary generative simulations were conducted for daylighting analysis to evaluate variations in the size, number, and placement of light wells and Design Builder 7.3.100.3 with Energy Plus 9.4 for CFD analysis for natural ventilation and indoor air temperature. After multiple generative design in accordance with the ECBC 17, filtered 7 options for best UDI results and these options were evaluated for natural ventilation by CFD analysis for the hottest and coolest hour. It was found that double light wells arranged perpendicular provided optimal results, with mean UDI above 50% and ACH ranging from 5.06 to 1.33. All high performing light well has a volume of more than 20% of the total built-up volume. Further the double rectangular light wells with dimension of 3.5 x 2.5 meters yielded the most effective results. This research offers a novel approach to design of light wells using generative design method for integrating passive daylight and ventilation systems in dense heritage urban settings. It demonstrates how generative design can guide regulatory development and sustainable solutions for tropical climates.