Pilot Phase of a Field Study to Determine Waste of Water and Energy in Residential Hot-Water Distribution Systems

This paper provides an overview of the pilot phase of a field study to determine the feasibility of a method of directly measuring the waste of water and energy caused by current hot water distribution systems (HWDS) in California residences using wireless sensor network technologies. The experience gained in the pilot phase study using wireless sensor networks demonstrates that it is clearly feasible to use this technology for measuring water and gas flows and temperatures.The goal was to demonstrate a method to reliably collect water flow and temperature data from every indoor hot water end use point, at the water heater in one second intervals when water was flowing. The overall success of the pilot phase study indicates that this technique can work. However, the pilot phase study did reveal shortcomings in many areas. The recommendations in this paper address those shortcomings and provide ways to improve the outcomes of any follow-on field study. The project's tasks were to test and evaluate the proposed hardware, installation protocols, data collection, and processing procedures. The techniques developed in this project provide a way to accurately measure temperature and flow of indoor water use events at one second resolution. The technologies used in this pilot phase study are viable for use in a larger field study to determine the energy and water efficiency of hot water distribution systems in California homes. The lessons learned from this experience will improve procedures, programming and wireless sensor network specifications.