Retrofit

Retrofitting Strategy	Conversion of air-cooled to water-cooled chiller plant
	The use of fresh water-cooled chiller plant has been encouraged in 2008. Water-cooled chillers are more efficient than air-cooled chillers as they can achieve a lower condenser refrigerant temperature. Conversion of air-cooled to water-cooled chiller plant can significantly enhance the chiller plant efficiency.
	Consideration
	Make reference to the latest Code of Practice for Fresh Water Cooling Towers Seeking EMSD’s, Water Supplies Department (WSD)’s and Buildings Department (BD)’s approval for using fresh water cooling tower scheme Review the building cooling load profile and combination between new chillers of different capacities, constant speed and/or variable speed types to best suit the profile. Partial of existing air-cooled chiller may be considered for standby purpose and winter mode for benefit-to-cost analysis. Installation of power meter, temperature sensors, and flowmeter or differential pressure sensor for monitoring the cooling energy, power and COP of chiller. Installation of power meter, differential pressure sensors together with the flowmeter and VSD devices for monitoring the power and W/L/s of air-conditioning pumps (Figure 2).
	Estimated Saving
	[(1/COP_CH_PRE – 1/COP_CH_POST) QBLDG + SkW_CWP_POST + SkW_CT_POST] 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)] SkW_CWP_POST = 0.605(0.88NCWP_SMkW_CWP_SM + 0.12NCWP_WN* kW_CWP_WN) + 0.395(0.184NCWP_SMkW_CWP_SM + 0.816NCWP_WNkW_CWP_WN) SkW_CT_POST = 0.605(0.88NCT_SMkW_CT_SM + 0.12NCT_WN kW_CT_WN) + 0.395(0.184NCT_SMkW_CT_SM + 0.816NCT_WNkW_CT_WN) OPHR,yr = hr/dayday/wk*52 Please click HERE to view the list of terminology.