A model of the domestic hot water load

The electrical load required to supply domestic hot water is an important load for two reasons: (1) it represents a large portion (30 to 50%) of the domestic load; and (2) it is a load which can easily be controlled by the consumer or the supplier, because the use of the hot water need not coincide with the heating of hot water. A model representing the power system load due to hot water consumption from storage water heaters is provided. Variable parameters include the average amount of water used, the mean and deviation of distributions of usage times, thermostat settings, inlet water temperature and electrical heating element ratings. These parameters are used to estimate the after diversity electricity demand profile, and were verified for accuracy by comparison with measurements. This model enables the prediction of the effects of load control, examples of which are given in this paper. The model is also useful for evaluation of the response which could be expected from demand-side management options. These include changing the size of heating elements, reduction in water consumption and reduction in thermostat settings