Retrofit

Retrofitting Strategy	Using electronically commutated (EC) plug fan in AHU / PAU / CRAC
	The traditional centrifugal fan technology in ventilation system has low efficiency. Replacing centrifugal fans of AHUs with EC plug fans can save 30-50% energy consumption. The EC fan’s built-in variable speed drive (VSD) and controller inside the motor get the signal from the temperature or pressure sensor to control the speed of drive.
	Consideration
	EC plug fans do not have belt and pulley or gear, so there will be less maintenance and consumables required. EC fan grid provides increased reliability to operation. If one fan fails, only a portion of the airflow is lost; if one fan loses its air flow, the rest will work faster to recover. Noise level is lower than centrifugal fans and may require fewer noise attenuation provisions.
	Estimated Saving
	(SkW_AHU_PRE – SkW_AHU_POST) OPHR,yr Where S kW_AHU_PRE = (0.605LF_SM,PRE + 0.395LF_WN,PRE)NAHUkW_AHU_PRE SkW_AHU_POST = (0.605LF_SM,POST + 0.395LF_WN,POST)NAHUkW_AHU_POST For CSD: LF_SM = LF_WN = 1, For VSD: LF_SM = 0.795, LF_WN = 0.562; For EC or DC-motor: LF_SM = 0.71, LF_WN = 0.38 OPHR,yr = hr/dayday/wk*52 Please click HERE to view the list of terminology.