Comparison of Cooling-Energy Performance Depending on the Economizer-Control Methods in an Office Building

Abstract Current building procedures seek to minimize external air supplies to reduce the energy consumption of air conditioning, resulting in a high dependency on mechanical ventilation. We therefore studied an economizer-cycle system, whereby the introduction of external air saves energy. We analyzed different economizer-control methods, addressing mixed-airtemperatures and outdoor-air fractions according to outdoor-air temperatures; also, we analyzed the energy consumption ofthe three economizer-cycle control types using detailed EnergyPlus simulation modeling. A differential enthalpy control methodshowed a lower energy consumption range from 5.8% to 6.2% than that of other methods during the simulated period. A differential dry-bulb control method showed a 12.7% lower energy consumption than the no-economizer method in the intermediate period, but also showed 7.1% more energy consumption during the summer period. When latent heat was not removed due to high summer humidity, we found a significant level of resultant energy consumption.