Minimization of unitary air-conditioning system power with real-time extremum seeking control

Abstract

Minimization of total system power in single-zone variable air volume unitary AC systems is beneficial for reduction in energy consumption. In this study, a dynamic model of a single-zone variable air volume system including space condition control loops is developed. Two optimal control loops for power minimization utilizing the method of real time optimization by extremum seeking are investigated: supply air leaving-air temperature control and capacity distribution control for two tandem compressors. Supply fan leaving-air temperature control is significantly impacted by the supply fan static pressure, where at low pressures, the optimal leaving-air temperature tends to increase, which may lead to humidity concerns. For the compressor modeled, the compressor capacity distribution control demonstrates a 10.8% power savings over an evenly distributed capacity to two identical compressors.