The effect of free cooling and demand-based ventilation on energy consumption of self-regulating and traditional chilled beam systems in cold climate

This paper presents the energy-saving potential of free cooling and demand-based ventilation with chilled beam system. In the analysis, four beam concepts were considered: standard, self-regulating, free cooling and demand-based ventilation chilled beam systems. The self-regulating chilled beam system utilizes high temperature water for cooling and there is no need for regulation valve. The inlet water temperature is close to room air temperature (20-22.,) and the room air temperature is allowed to vary between 21 and 25.,. The free cooling for the inlet water is provided by the preheat coil of the air handling unit. The introduction of demand-based ventilation further increases the energy efficiency. Energy consumption of the robust self-regulating system is slightly higher than with traditional chilled beam system: self-regulating system keeps the room air temperature lower than with traditional beam system. With free cooling, it is possible to save about 15% of the delivered energy compared with the standard beam system. With the occupancy rate of 60%, energy consumption is reduced by 36% with demand-based ventilation, respectively. When both free cooling and demand-based ventilation are used with 60% occupancy rate, the energy consumption is 44% lower than with the traditional beam system.