In an urban setup optimum size of rainwater tank is a critical factor, as the space required for the rainwater tank is limited and expensive. Several methods have been used for the analysis of potential rainwater harvesting. Some authors used Rippl method for rainwater tank sizing. However, through Rippl method, required size often becomes too big and not feasible in an urban space. This paper presents a water balance modelling concept for rainwater harvesting analysis and its application in determining optimum tank size for rainwater harvesting. Results of the daily water balance model were compared with an earlier study results through Rippl method using daily rainfall data for the city of Nablus (Palestine). Daily rainfall data was collected for the city and from the collected data, three years were selected as dry, average and wet years. Using a typical average rainwater

demand and the roof sizes used in the published study, and daily rainfall data for the selected years, annual water savings were calculated for varying tank sizes. From the simulated results, it is clear that for tank sizes beyond certain threshold volumes, annual expected water savings remain unchanged. It is found that Rippl method calculated optimum tank sizes are almost double the optimum tank sizes determined through eTank simulations. Finally, several optimum tank sizes were calculated for different roof sizes and demands considering an average weather condition. It is found that the optimum tank sizes can be correlated with the roof size and rainwater demand, which can be incorporated into a single generalised equation for optimum tank size. The equation calculated results are very close to the original optimum tank sizes found through manual calculation. 

Title

Journal of Cleaner Production

Publisher

Elsevier

Publisher Country

Netherlands

Indexing

Scopus

Impact Factor

9.297

Publication Type

Both (Printed and Online)

Volume

324

Year

2022

Pages

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