Using thermal transients at the outlet of electrical water heaters to recognise consumption patterns for heating schedule optimisation

In the midst of environmental concerns, and soaring energy costs and energy shortages, the efficiency of electrical household water heaters (EWHs) has been identified as an area with significant potential for savings. The benefits of applying optimised scheduling control for EWHs has been proven by various studies, however, little has been done to measure individual behaviour. This paper presents an alternative to the invasive and expensive solution of using water flow meters. A hardware and algorithmic solution is presented that uses thermal transients at the outlet of an EWH to measure consumption patterns. The results show that the approach is able to detect usage events with an accuracy of 91%. Despite the challenges related to thermal inaccuracies, event durations are estimated to within 2 minutes accuracy 79% of the time.