Ventilation-dominated energy savings in large commercial buildings: Multi-measure assessment revealing HVAC optimization priorities for hot-humid climates

초록

Commercial buildings consume 20-40 % of global energy and generate 40 % of energy-related carbon emissions, yet energy efficiency research exhibits a persistent geographic bias toward temperate climates and systematic underrepresentation of large commercial buildings (>10,000 m(2)), which account for 35 % of commercial floorspace despite comprising only 2 % of all buildings. This study addresses these dual research gaps by systematically evaluating and ranking four energy efficiency measures (EEMs) for a 20,000 m(2) office building in hot-humid Texas through calibrated EnergyPlus simulation: lighting and plug load management, VAV minimum airflow optimization, outdoor air control, and chilled water temperature reset. The comprehensive analysis reveals a climate- and scale-specific energy-saving hierarchy that fundamentally challenges conventional methodologies. Outdoor air control achieved the highest individual savings (12.45 % electricity, 19.33 % chilled water), while ventilation-related measures collectively dominated with over 60 % of total achievable savings-a striking contrast to temperate climates and smaller buildings where lighting and equipment upgrades typically receive priority. Integrated implementation of all measures yielded 20.77 % electricity and 27.97 % chilled water savings, totaling 1,204,502 kWh annually. These findings demonstrate that in large buildings operating in hot-humid climates, strategic HVAC optimization delivers superior returns compared to traditional equipment-focused approaches, providing a replicable framework for climate-responsive retrofit planning.

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