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Liujia Dong, University of Texas at Dallas
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Yaoyu Li, University of Texas at Dallas
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Timothy Salsbury, Ph.D., Johnson Controls, Inc.
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John House, Ph.D., Johnson Controls, Inc.
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Zhigang Wu, Ph.D., Johnson Controls, Inc., Asia Engineering Center
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Lee Wang, Ph.D., Johnson Controls, Inc., Asia Engineering Center
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The variable refrigerant flow (VRF) technology provides multi-split ductless configurations that typically use one outdoor unit (ODU) and multiple indoor units (IDU). VRF systems offer many advantages, such as elimination of duct loss of air distribution, design and installation flexibility, compactness, integrated controls, quiet operation and reduced maintenance cost. Also, multi-functional VRF (MFVRF) systems have achieved remarkable development, offering flexible operation of individualized zoning control, i.e. making possible simultaneous heating and cooling in addition to cooling or heating only modes. Meanwhile, such flexibility further complicates the operation and control due to diversified system configurations and highly variable operational loads. This paper proposes extremum seeking control (ESC) schemes for MFVRF system under different operational modes, in order to maximize the efficiency provided the satisfaction of thermal comfort.
