Identification of Energy-Saving Factors from Hybrid Ventilation in Heritage Building

Abstract

Heritage buildings in tropical cities face challenges in balancing energy efficiency with conservation constraints. The aim of this study is to identify the energy-saving factor of the hybrid ventilation system (combining ceiling fans and air conditioning) in Locaahands Tunjungan Restaurant, a colonial heritage building in Surabaya. Field observations and literature-based predicted analysis were conducted to identify factors influencing energy savings, including fan mode, airflow rate, fan position, and AC inlet placement that was evaluated by Archimedes number, uniformity coefficients, turbulence intensity, and comfort indices from previous research. Results indicate that ceiling-fan-integrated air conditioning improves indoor air distribution, reduces reliance on additional AC units, and enhances thermal comfort while lowering energy demand. The downward fan mode at moderate speed provided optimal comfort in dining areas, maintaining air velocity within ASHRAE standards (0.1–0.8 m/s). This strategy allows adaptive reuse of heritage buildings without compromising their historical integrity, offering an energy-efficient alternative to conventional HVAC systems and contributing to urban heat island mitigation.