Effects of Solar Water Heating Systems on the Electric Utility. Residential Conservation Demonstration Program

摘要

This report presents the results of a residential demonstration project relating to the effects of solar water heating systems with electric back-up on the electric utilities. The project, which was funded by the Florida Public Service Commission, was conducted in Gainesville, Florida, where 22 customers of the Gainesville Regional Utilities system took part in the study. Additional funding for a portion of Gainesville Regional Utilities' participation in the project was provided by the City of Gainesville. The study group was comprised of 10 participants with conventional electric water heaters, 6 participants with existing solar water heaters, and 6 participants who purchased new solar water heaters (with electric back-up) which were designed and installed with strong emphasis placed on performance and quality. The participants' water heating systems were monitored at 15-minute intervals to determine: hot water use, net energy content of hot water, and electrical consumption. The study also involved investigating the potential use of a Transient System Simulation Program (TRNSYS) for solar water heaters to predict the electric back-up requirements in order to provide a means of forecasting coincident peaks with the electric utility. Study results show that solar water heaters with electric back-up contribute less to the utility's coincident demand than do conventional electric water heaters. While both groups of solar participants had lower electric consumption per gallon than did the conventional electric (CELE) participants, the new solar (NSOL) water heating systems were much more effective than the existing solar (ESOL) water heating systems. The major contributing factors to this difference were better system design and overall quality of workmanship. Use of the TRNSYS simulation program to forecast coincident peaks did not provide the desired reliable results. (ERA citation 09:004546)