Optimal control of fan coil battery air and water flow rates requiring minimal on-line measurements

Fan coil units are widely used in air-conditioning systems for heating and cooling of commercial buildings. Control - capable of achieving better operational efficiencies and at the same time, guarantying thermal comfort - is paramount in order to achieve optimal operation. The present paper presents a novel generalised control strategy, requiring only minimal input data, for optimising fan speed in order to reduce. Different control models are implemented to predict fan coil capacities and associated total power consumption. The developed strategy has been compared to fixed speed and benchmark fan speed control strategies, using both a steady state and a quasi-steady state algorithm, for various building loads. Results show average reduction in fan coil battery power consumption of 34% and 43% in heating and cooling mode respectively, when the optimal control is compared to fixed fan speed settings. Savings between 4.9% and 9.1% can be achieved by the control algorithms if compared to the benchmark fan speed control strategies.