Energy saving simulation analysis for different fans design applied to variable air volume systems

Variable air volume (VAV) systems have been shown to have significant potential to reduce air-conditioning energy. This study is an attempt to analyze high and low efficiency fans when applied to VAV system the potential of energy saving. Three types of VAV systems: variable frequency drive, damper control (pressure control) and fan blade pitch are studied. Annual hourly dynamic energy simulation with a commercial building case has been studied. The cost benefit is also discussed. It has been found that air-conditioning operates at low load more than 70% of the time. Even low efficient fans with frequency control would have good energy saving potential. In comparison frequency control can save about 30% of energy use over that of damper control. High efficiency fans could out performance low efficiency ones by as much as 35% in energy saving. Altogether six application models were analyzed for cost-benefit. For high or low average cooling load high efficiency fans are good selection. For system averagely at low load variable frequency control is a better choice. For medium load most of the time variable fan blade pitch is advantageous. For average high load damper pressure control can be selected.