TOWARDS DEVELOPMENT OF AN ALGORITHM FOR MAINS WATER TEMPERATURE

Abstract

Mains water temperature (Tmains) has significant influence on the energy consumption of water heating equipment. It is dominantly influenced by ambient temperature (Tamb). Since Tamb is roughly an annual sinusoid, Tmains is assumed to be a sinusoid whose mean value varies directly with annual average temperature Tamb,ann. Model parameters are based on water system physics and include: i) a constant offset from Tamb,ann; and ii) amplitude and phase which vary linearly with Tamb,ann. Available Tmains data indicate that the offset is ~6 oF, and that the amplitude is ~0.4∆Tamb Uncertainties include: i) data quality issues, including bias of Tmains data from heat exchange with house air; ii) inherent spatial variations in mains networks, and iii) limited data sets. Future work includes acquiring quality data sets, testing the model in northern climates, and.refining parameter estimates.