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Cost-benefit analysis of water supply pump replacement in buildings of Hong Kong

Brief:

Energy efficiency of water supply systems in buildings becomes a concern for sustainable development nowadays. Aged, poor maintained and mismatched water pumps operating at low efficiency are highly undesired situations that can cause energy loss in water supply systems. This paper investigates in-use water pump efficiency and the associated energy cost for water supply systems in high-rise buildings of Hong Kong.Energy consumptions of water supply pumps are measured with the pump efficiencies determined from the water consumptions in 20 water supply systems in buildings. This paper presents expressions of in-use pump efficiency as a function of pump age and the associated energy cost is predicted against the pump installation cost. Pump replacement schedule is proposed with justification by the installation cost against the energy cost saving. The results show that a larger system could be benefited by a more frequent pump replacement schedule as compared with the ones of smaller pumps. The cost benefit is also observed for the worst scenarios of pump efficiency drops. The benefit isobvious as pump energy cost is high as compared with the installation.

Further information:

Wong LT, Zhou Y, Mui KW, 2015. Cost-benefit analysis of water supply pump replacement in buildings of Hong Kong, The 41st CIBW062 International Symposium of Water Supply and Drainage for Buildings, 18-20 August, Beijing, China. 560-566.