Architectural envelopes have a key role in reducing a building's energy consumption and achieving thermal comfort. Many adaptive building envelopes are developed through synthesis with biomimetics for increased performance, but most adapt to a single environmental factor, while living organisms evolved several adaptation solutions that are high-response and multi-functional. However, existing methodologies to develop biomimetic adaptive building enve-lopes focus on monofunctional systems, which are limited in addressing multifunctional. This paper proposes a novel integrated methodology to develop the design of a multi-functional bio-mimetic adaptive building envelope by transforming the biological adaptation systems in nature into bio-inspired adaptation mechanisms and merging them into one technical system hosting multiple functions. The merging process is conducted based on the various static and dynamic biological mechanisms' sizes, forms, processes, and functions. The methodology is demonstrated through the MBio-ABE case study, which results from the merging process of different biological mechanisms for Mimosa pudica, Cactus (Echinocactus grusonii), and Stone Plant (Lithops sali-cola). Thereafter, building performance simulation using EnergyPlus is conducted and the results are evaluated through an optimization process using an algorithm based on Python software to measure the thermal comfort level. The results showed a considerable improvement in the thermal performance of the multi-functional biomimetic adaptive building envelope, which decreased the temperature inside by 3 degrees C through only natural ventilation. Additionally, the average thermal comfort conditions over the year increased by 11.3%. Obviously, the merging process plays a significant role in achieving multifunctionality in the biomimetic adaptive building envelope to improve the performance of traditional building envelopes.
