Keywords: two-pipe fan-coil units, energy efficiency, dry fan-coil mode, wet fan-coil mode, changeover time, fresh air supply, air conditioning, dehumidifying, energy consumption, energy conservation
Energy-efficient operation of two-pipe fan-coil unit system with independent fresh air supply
Year-round energy-efficient operation is presented for a two-pipe fan-coil unit air-conditioning system with independent fresh air supply. The study investigated two typical in-room fan-coil operating modes: the dry fan-coil mode in which the room cooling coil does no latent cooling and the wet fan-coil mode in which the room cooling coil is used for dehumidifying a part of moisture from conditioned space. The investigation shows that for a given indoor temperature and relative humidity level, the changeover time of hot-cold water is same in dry fan-coil mode and wet fan-coil mode, but the operating energy consumption required in dry fan-coil mode is more than that required in wet fan-coil mode during the periods of intermediate and summer seasons.