Retrofit

Retrofitting Strategy	Replacement of more efficient chiller
	Efficiency of existing chillers will drop after operating for several years. Efficiency of existing chillers should be monitored and planned for replacement when there is a reasonable improvement opportunity.
	Consideration
	Compare the chiller efficiency with the latest BEC. Review the building cooling load profile and combination between new and existing chillers. The new combination may consist of chillers of different capacities, constant speed and/or variable speed types to best suit the profile. Use water- / evaporative- cooled chillers, if possible. Installation of power meter, temperature sensors, and flowmeter or differential pressure sensors for monitoring the power, cooling energy and COP of chiller (Figure 1).
	Estimated Saving
	(1/COP_CH_PRE – 1/COP_CH_POST) QBLDG OPHR,yr Where COP_CH = 0.605COP_CH_SM + 0.395COP_CH_WN COP_CH_SM = (COPa_SM + COPb_SM)/2; COP_CH_WN = (COPa_WN + COPb_WN)/2 QBLDG = 0.605[0.77(0.88NCH_SMQCH_SM + 0.12NCH_WNQCH_WN)] + 0.395[0.596(0.184NCH_SMQCH_SM + 0.816NCH_SMQCH_SM)] OPHR,yr = hr/dayday/wk52 For CSD_WSS: COPa_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(0.77 – 0.75)/(1 – 0.75) COPb_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(TWCC_SM – 23.9)/(29.4 – 23.9) COPa_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(0.596 – 0.375)/(0.75 – 0.375) COPb_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(TWCC_WN – 18.3)/(23.9– 18.3) For VSD_WSS: COPa_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(0.67 – 0.75)/(1 – 0.75) COPb_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(TWCC_SM – 23.9)/(29.4 – 23.9) COPa_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(0.496 – 0.375)/(0.75 – 0.375) COPb_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(TWCC_WN – 18.3)/(23.9 – 18.3) For CSD_ASS: COPa_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(0.77 – 0.75)/(1 – 0.75) COPb_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(TACC_SM – 26.7)/(35 – 26.7) COPa_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(0.596 – 0.375)/(0.75 – 0.375) COPb_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(TACC_WN – 15.6)/(26.7– 15.6) For VSD_ASS: COPa_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(0.67 – 0.75)/(1 – 0.75) COPb_SM = COP_CH_75% + (COP_CH_100% – COP_CH_75%)(TACC_SM – 26.7)/(35 – 26.7) COPa_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(0.496 – 0.375)/(0.75 – 0.375) COPb_WN = COP_CH_38% + (COP_CH_75% – COP_CH_38%)(TACC_WN – 15.6)/(26.7– 15.6) Where COP_CH_38% = COP_CH_50% + COP_CH_50% TACC_SM = 28.8, TACC_WN = 21.2, TWCC_SM =28.5, TWCC_WN = 25.0 Please click HERE to view the list of terminology.