Calculating the optimum level of apparent losses due to meter inaccuracies
Up to date several papers have dealt with the optimum replacement frequency of installed water meters. These works have concluded that water meters should be replaced based on the meter acquisition and installation costs, the selling price of water, the interest rates of money and the degradation rate of the weighted error. This last parameter, as commonly known, it is calculated from the evolution with time of the error curve of the meters and the consumption characteristics of the customers. Arregui et al. 2006 presented an economical model and a simple graphical method to determine the optimum replacement period based on these parameters.
Similarly, this paper will present the continuation of this work, showing a graphical method that will allow determining the optimum level of apparent losses caused by meter inaccuracies (other components of apparent losses are not considered). This calculation is strictly conducted from an economical point of view, without considering other factors - for example legal restrictions, sociological issues, etc…- that may affect the optimum replacement period of the meters and, therefore, the optimum level of water meter inaccuracies.
As expected, the optimum level of meter inaccuracies will depend on the same parameters as the optimum replacement period calculation of installed water meters. For simplicity and facility of use, the solution to the problem is condensed in a single chart which has been prepared running thousands of simulations on the economic model presented by Arregui et. al (2006) for the calculation of the optimum replacement period of water meters. In each case, the average error of installed meters, when conducting a replacement program within the optimum period, has been considered.