Harmonic oscillator tank: A new method for leakage and energy reduction in a water distribution network with pressure driven demand

Abstract

It is now well established that rate of leakage of water is directly related to the distribution pressure in a network. In this context, pumps can consume up to 60% of the overall energy requirement in the case of pressure driven demand whereby they are solicited for direct supply. In this paper, we investigate the energy efficiency of distribution in an experimental network which is embedded with two levels of leakage (low and high) using three different methods. They are analysed and compared in terms of specific energy consumption and rate of leakage. A novel concept known as the Harmonic Oscillator Tank has been developed whereby the conventional hydropneumatic tank is pressure modulated so as to produce a constant output flowrate within the presence of leaks. Experimental results show that the throughput of the Harmonic Oscillator Tank for a heavy leaking network is highest (86.45%) with the lowest percentage leakage of 13.5% at a specific energy consumption of only 0.354 kWh/m3/day when compared to the other two schemes namely direct pumping and pumping through a variable speed drive in a loop. This Harmonic Oscillator Tank opens up new avenues for reducing energy and leakage in old damaged networks whereby a short or medium-term solution is often required since infrastructure renewal requires time and a massive investment.