Distribution System Efficiencies: Energy Saving Investigation Process
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- Ensure that all PRVs are properly maintained and tuned to provide optimum pressure levels which may, in turn, reduce accompanying distribution system water losses.
- Review fire hydrants annually and test for possible leaks.
- Keep a centrally accessible and well-maintained set of pipe location and leak detection instruments to ensure rapid and accurate assessments of infrastructure.
- Investigate installing a centrally located and efficiently accountable bulk water filling station for construction water—minimizing water losses and unauthorized use by contractors.
- Develop and implement a distribution system flushing program to ensure that water quality is maintained as well as friction losses minimized and water quality is optimized.
- Review and maintain key air-vac and air release devices in the distribution system to ensure that they are functioning properly with no build-up of air. This will maximize the flow of water and can significantly decrease energy demands. Ensure that high points of distribution piping have air regulation devices. Even a partially air locked pipe can use significant energy in pumping.
- Where practical, install customer services in the top zone of distribution piping (and at pipe high points) to ensure air is kept out of the piping systems and reduce the need for air-vac devices.
- To optimize energy efficiency on any raw un-treated water transmission lines—implement pipeline pigging programs to ensure that pipe wall friction coefficients are maintained at a minimum, thus reducing pumping energy costs.
- Model the distribution system using a steady state AND extended period models, to evaluate possible undersized piping systems and networks, including water flow patterns, water quality characteristics, and energy demands over different scenarios. (See System Modeling Efficiencies).
- Test water for possible tuberculation and corrosion (iron and sulfur reducing bacteria, and Langelier index) issues which can impose energy inefficiencies.
- Be careful not to crush PE piping in new piping installations.
- Investigate the installation of real-time pressure transducer monitoring at key distribution sites and use the data to calibrate system models.
- Implement and monitor Backflow testing programs to protect water quality, and ensure that these protection devices are not leaking.
- Check the distribution system for partially closed or lost isolation valves. Know the valve rotation counts for various diameters of pipe. Verify these diameters with the piping models and record drawings.
- Investigate pipe network looping and additional network upgrades in the system to reduce head losses on pumping systems, etc.
- Specify pipe materials which have a higher “C” coefficient in future upgrades or expansions.
- Incorporated pressure management PRV control valve systems where practical. These systems can drop the pressure from say, 110 psi to 70 psi during low demand periods, which helps to reduce water use and lower the leak rates. It also limits the wear and tear on the water system. But when higher flows are needed in that zone, the pressure automatically increases to the higher pressure for such use as fire-flow or heavy demand. When demand subsides, the valve automatically returns to the lower settings.
- Develop an upgrade plan for piping systems which are deficient in size, materials, or quality.