A comparative study of common uses of selected modelling tools for evaluating rainwater harvesting strategies

In a similar way to as they are commonly used in industry, results from PURRS (v7.2), MUSIC(v3) and Spreadsheet modelling tools were compared for evaluating rainwater harvesting strategies. Input data to each model was selected as advised by user guidelines, including climate files, suggested water demands and time-steps. Models were run with climate data of unequal duration and time-step, which highlighted significant differences between modelled outcomes. Using climate data of equal duration still resulted in major differences. The reasons for these differences are explained as a function of the duration and time-step of climate data, the time-step and diurnal patterns of indoor/outdoor water demand and tank configuration. Results imply that the length and time-step of climate inputs, the distribution and time-step of daily water demand and rainwater tank configuration are significant factors in robustly evaluating mains water savings for a range of Australian climates.