In this study, the following assumptions are made:
• The hot water temperature in the entire tank is the same.
• The ambient and the inlet water temperature (Ta and Tin) are constant during the day.
• The variation of Td does not affect Wd.
The variation of TH for one day is shown in Fig. 1(a) using the ASHRAE Wd schedule shown in Fig. 1(b). The instantaneous power consumed by the EWH is shown in Fig. 1(c). A simulation (time) step of 0.0001 h was considered.