Retrofit

Retrofitting Strategy	Conversion to variable speed cooling tower fan
	Using more cooling tower per chiller and pump can lower the condensing temperature and improve the COP of chiller during summer while less air is required for heat rejection of cooling tower if the ambient wet bulb is sufficient low during winter. Conversion the constant speed fan to variable speed control for cooling tower can reduce fan power during part load conditions by optimizing the air-to-water flow ratio of cooling tower that needed for heat rejection.
	Consideration
	A designed condensing water leaving temperature profile of cooling tower should be developed based on the approach temperature of cooling tower at different ambient wet bulb temperature and condensing water entering temperature of cooling tower Use the designed condensing water entering temperature profile of cooling tower to adjust the fan speed and nos. of cooling tower to improve the overall efficiency of chiller and heat rejection system. Installation of power meter, temperature sensors, and differential pressure sensor for monitoring the power, heat rejection capacity, W/L/s and COP of cooling tower. (Figure 3).
	Estimated Saving
	(SkW_CT_PRE – SkW_CT_POST) OPHR,yr Where S kW_CT_PRE = 0.605LF_SM,PRE(0.88NCT_SMkW_CT_SM + 0.12NCT_WN* kW_CT_WN) + LF_WN,PRE (0.184NCT_SMkW_CT_SM + 0.816NCT_WNkW_CT_WN) SkW_CT_POST = 0.605LF_SM,POST(0.88NCT_SMkW_CT_SM + 0.12NCT_WN* kW_CT_WN) + 0.395* LF_WN,POST(0.184NCT_SMkW_CT_SM + 0.816NCT_WNkW_CT_WN) 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.