Electric water heaters with more than two elements combined with multiple setback thermostats can be an effective means of reducing peak loads. The calculations method presented was developed to simulate the operation of such appliances. The main features of this method are - A dynamic discretisation scheme representing the water temperature distribution in the tank and its variation with time in an appropriate way. This method also takes into account the effects of the different heater elements, their operational priorities, location, and controlling thermostat setpoints. The heat dissipation model is based on the assumption that mixing is negligible between the upward heated stream and the surrounding, or downward, colder water. Heat transfers between different zones of the water heater and through the envelope of the appliance are evaluated using explicit calculation technique. This simulation method has been used to evaluate the load reduction potential of the new concept of multi-element electric water heaters. The results prove that heating demand during peak periods and standby heat loss are both reduced.

KEYWORDS: water heaters, electric heaters, calculating, domestic, operations, heat flow, heating elements, energy consumption, energy conservation, water tanks, heat loss