Developing Generalised Equation for the Calculation of PayBack Period for Rainwater Harvesting Systems

Many end-users for the stormwater harvesting systems are reluctant in implementing system due to uncertainties of potential returns their investment such system. A common practice presenting benefit a certain is through calculation payback period using net annual from Traditional doing analysis rainwater tanks was considering individual building/roof, volume, and specific cost. It not feasible conduct each every installed different buildings. To overcome this tedious practice, study presents development generalised equation estimation based on roof area, initial cost, rate return. Based an earlier study, several periods were calculated sizes, costs, found that all these variables can be correlated embedded into base power function. Final developed results compared with traditional savings present value cumulative savings. estimate very good accuracies; selected internal rates return correlation values ranging 0.99 1.0 achieved. Corresponding coefficient determinations varied 0.988 0.993. Furthermore, it fixed area return, having relationship (having exponent less than 1.0)