Mechanical and HVAC interventions in the adaptive reuse of historic Khan structures as hotels: a comparative study of Çukur khan and Zincirli Khan

The integration of modern Mechanical, Electrical, and Plumbing (MEP) systems into historic load-bearing structures constitutes a considerable technical challenge in heritage conservation. This study examines the spatial and volumetric impacts of HVAC interventions in the adaptive reuse of Ottoman-era caravanserais (khans) as boutique hotels, comparing the divergent strategies employed at Çukur Khan (Ankara) and Zincirli Khan (Aydın) in Turkey. Using a qualitative comparative approach that combined archival research and on-site analysis, interventions were evaluated against international conservation standards, with particular attention to reversibility and the preservation of spatial hierarchy. The analysis demonstrates that Çukur Khan’s “interventionist” strategy – comprising the enclosure of the central courtyard and the creation of subterranean volumes for centralized plant equipment – resulted in a high impact on the building’s authenticity and spatial legibility. Conversely, Zincirli Khan adhered to a “conservative” model by maintaining an open courtyard and utilizing decentralized mechanical systems, thereby limiting physical alterations to secondary zones. The findings demonstrate that HVAC topology is a primary driver of architectural change in adaptive reuse projects. Early interdisciplinary coordination between conservation architects and building services engineers is therefore essential to reconcile contemporary comfort standards with the integrity of historic fabric.