Pump efficiency of water supply systems in buildings of Hong Kong

Abstract

Energy efficiency of water supply systems in high-rise residential buildings becomes a concern for sustainable development nowadays. It has been reported the energy efficiency for high-rise water supply systems is below 25% and more than 75% input energy is 'lost', about half of the energy loss attributes to water pumps. Water pump operating at low efficiency is highly undesired. This paper investigates the in-use water pump efficiency for water supply systems in high-rise buildings of Hong Kong. The pumping efficiencies evaluated from a survey of 20 high- rise water supply systems were presented as a function of installation time. Expressions of in-use pump efficiency were proposed and pump replacement time was suggested. Better performed pumps got longer suggested service period and poorer performed ones got shorter payback periods. More frequent replacement was suggested for larger pumps and the payback period was generally shorter.