Energy storage arrangement and installations

A method of controlling a heating appliance in a hot water supply system, the hot water supply system having a controllable hot water supply outlet having when fully opened a given flowrate, the controllable hot water supply outlet being configured to receive hot water from a hot water supply line having a valve therein, and the heating appliance including:

• a processor;
• a renewable energy source comprising a solar water heating arrangement or a heat pump, the renewable energy source being configured to be able to receive cold water and to heat it to be supplied to the controllable hot water supply outlet via the valve in the hot water supply line;
• a thermal energy store, containing a thermal storage medium to store thermal energy, that is configured to receive energy from the renewable energy source and to be able to receive water and to heat it to be supplied to the controllable hot water supply outlet via the valve in the hot water supply line;
• an auxiliary water heater intermediate the valve in the hot water supply line and the controllable hot water supply outlet;
• the hot water supply system being operable, under the control of the processor, to heat water that is to be supplied to the controllable hot water supply outlet to a target system supply temperature using a selection of one or more of the renewable energy source, the thermal energy store, and the auxiliary water heater;
• wherein the thermal energy store has an energy storage capacity, when fully charged, that is sufficient to provide hot water to the controllable hot water supply outlet, at the given flowrate, and at the target system supply temperature for a period of at least 8 minutes;
• and
• wherein the renewable energy source is also configured to provide building heating under control of the processor, the method comprising:
• monitoring actual demand for hot water from the hot water supply system;
• predicting future demand for hot water from the hot water supply system based on the monitored actual demand;
• pre-charging the thermal energy store so that sufficient energy will be stored in the thermal energy store to satisfy the predicted demand;
• and
• temporarily diverting heat from the renewable energy source to charge the thermal storage medium rather than to provide building heating.