Regional-scale variability of cold water temperature: Implications for household water-related energy demand

摘要

Residential water use accounts for at least 80% of water-related energy (WRE) demand (primarily through water heating) in the residential urban water system. Cold water temperature (CWT) is a key determinant in predicting residential WRE but variation of CWT within water networks has not been quantified and is not accounted for in water heating energy consumption guidelines. Here, we analysed the spatiotemporal variability in CWT over the course of a year (2013) using 5760 measurements from 1255 urban water system sampling locations across the Yarra Valley Water region in Melbourne, Australia. CWT varied across the study site from 12-28 degrees C during summer and 9-15 degrees C during winter. Spatial clusters of higher CWT regions (hot spots) and lower CWT regions (cold spots) were also observed. The CWT variability impact on annual household WRE demand was estimated to be between 17 to +19% (-640 to +680 kWh/hh.yr) change in water heating for sample households, which is dependent on the geographical location of the household within the study site. However, households located in cold spot regions will have almost twice the amount of WRE demand than average, conversely, WRE demand will be lower than average in hot spot regions.