Engineering and Economic Analysis of Water-saving Fixtures. ANTONY HAYES (Merced College Merced, CA 95348) BLAIR HORST (Lawrence Livermore National Laboratory, Livermore, CA, 94550)

Reducing water consumption reduces water purchasing and pumping costs, as well as sewer discharge fees. The proposal is to replace urinals that are not water efficient at the Lawrence Livermore National Laboratory (LLNL). Before executing such a project, locations of replacements must be known, justification and the benefits of such a project must be clear, provided in the form of a preliminary analysis of water, energy, and monetary savings. Reducing water consumption and discharge to the sanitary sewer reduces costs as well as contributes towards compliance with various regulations. An initial investment consisting of purchase and installation of low-flow fixtures would result in long-term savings for the LLNL. This project includes surveying the restrooms at LLNL to inventory the toilets, urinals, faucets, showerheads, and lighting controls. Water volume saved by installing the fixtures is the most important factor. The other factors are the price of electricity, water, and sewage per unit of water. Based on the amount of water saved, we can calculate electricity savings, sewer savings, and water savings. These savings, and the costs for purchase and installation of the fixtures are used to calculate simple payback, the metric used to determine where retrofits are economically justified.. A simple estimate shows that the LLNL could save 28 million gallons of water per year, which results in a savings of over $285,000 per year by replacing water closets and urinals with low flow fixtures. The simple payback of replacing the fixtures at LLNL is just over 3 years. This project could reduce the total use of water at LLNL by over 9%. Future work will yield more accurate and in-depth knowledge of the benefits of executing such a project. This work was performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.