Water Journal : Water Journal March 2011
smart water systems & metering refereed paper technical features 100 MARCH 2011 water higher energy intensity due to the sharp fluctuation in water demand (for example, a 240- to 440-second period), overall the mean flow rate is considerably higher than those for toilet events, thereby working closer to the pump's optimal operating range. Irrigation events were recognised as having the lowest energy intensity (ie, 1.037 to 1.040) due to the pump working at its optimal range to supply a constant flow rate for the majority of the event period. Efficiency is only reduced for a short duration at the start and end of the event. Figure 9 illustrates the energy intensity for a short irrigation event. In summary, the above sample results demonstrate that the commenced ARC Linkage Project will be able to provide an extensive matrix showing the energy intensity for a range of pump configurations for the mandated end uses. Such a matrix will undoubtedly provide evidence to develop robust rain tank pump policy and practice guidelines for implementation. Pilot Study Summary The key points of this pilot study are listed as follows: • An experimental method has been designed that enables high-resolution data collection for both the mains and rain tank supplied end uses and their respective pump energy requirements. • A reliable data analysis procedure has been developed for resolving all household end uses through one smart meter at the front of the property and two near the rain tank (ie, on each side of the switch system), enabling water balance analysis at an end use level. • Developing a data collection and analysis procedure for aligning end use event water and energy requirements (ie, energy intensity) for the mandated rainwater tank supplied end uses, paving the way for further innovative research in this area. • Lastly, the pilot study provides the basis for a larger, recently commenced ARC Linkage Project (12-24 months for 50 households). Future Work: ARC Linkage Project Outcomes derived from the more significant ARC Linkage Project that evolved from this pilot study include the following: • Development of physical data sets on mains and rain tank water end usage, potable savings and energy use, linked with socio-demographic, environmental and stock efficiency factors. • Development of an evidence-based assessment on the reliable supply of internally plumbed rain tanks across different household usage patterns, demographic groups, regional contexts, and in relation to relevant policy including potable savings estimates/ targets. • Completion of a rain tank performance improvement study outlining key Figure 8: Clothes washer energy intensity. Figure 9: Short irrigation event energy intensity plot.
Water Journal April 2011