Determining the Outdoor Air Intake Dry-Bulb Temperature Range for Economizer Applications in Data Centers

This study aimed to identify the optimal outdoor air (OA) intake temperature range for the application of a dry-bulb temperature-based air-side economizer in data centers. To this end, a series of parametric simulations was conducted using EnergyPlus (version 24.1.0) and a previously validated small-to-medium-scale data center model situated in Daejeon, South Korea (ASHRAE Climate Zone 4A). A parametric analysis was performed by varying the maximum allowable OA intake dry-bulb temperature from 10 to 18 °C in 2 °C increments. The simulation results indicated that OA intake was limited during the summer due to high humidity levels, whereas it was more viable during the winter and interseason period. However, when the maximum OA intake dry-bulb temperature exceeded 14 °C, the increase in latent heat load caused humidity increased overall energy consumption. To expand the applicable range for air-side economizer operation, the cooling system capacity was adjusted. The scenario with a 14 °C OA threshold demonstrated the most favorable balance between energy efficiency and compliance with operating environmental criteria. The findings of this study provide a technical basis for establishing OA intake guidelines in dry-bulb temperature-based economizer control. However, further field-based validation is required to verify the effectiveness of these simulation results under real-world operating conditions.