A heat pump water heater has a tank, a heat source, and a heat pump system. The heat pump system has a refrigerant path, at least a portion of which is in thermal communication with the water tank volume so that heat transfers from refrigerant to the water tank volume. A fan causes air to flow through a housing, and another portion of the refrigerant path includes an evaporator in the housing. The fan is within the housing and may further be within a second housing. The first housing may comprise a baffle to direct air flow. The fan may be a variable speed fan in communication with a controller, so that the controller controls the fan speed depending on a temperature of the refrigerant.

There is provided a hot water supply system including: a controllable hot water supply outlet having when fully opened a given flowrate; a thermal energy store, containing an energy storage medium comprising a phase change material to store energy as latent heat, that is configured to receive energy from a source of renewable energy; a renewable energy source; the hot water supply system being operable, under the control of the processor, to heat water that is to be supplied to the hot water outlet to a target system supply temperature using a selection of one or more of the renewable energy source, energy from the thermal energy store, and optionally an auxiliary water heater intermediate the thermal energy store and the hot water supply outlet; wherein the thermal energy store has an energy storage capacity, when fully charged, that is sufficient to provide hot water to the hot water outlet, at the given flowrate, and at the target system supply temperature for a period of at least 8 minutes, and preferably at least 10 minutes; wherein the renewable energy source is also configured to provide building heating under control of the processor; the processor being configured to: monitor actual demand for hot water from the hot water supply system; predict future demand for hot water from the hot water supply system based on the monitored actual demand; pre-charge the thermal energy store so that sufficient energy will be stored in the thermal energy store to satisfy the predicted demand; and to temporarily divert heat from the renewable energy source to charge the phase change material rather than to provide building heating. A corresponding method is also provided.

The present disclosure provides a computer-implemented method of defrosting a heat pump of a water provision system installed in a building, the water provision system comprising the heat pump configured to transfer thermal energy from outside the building to a thermal energy storage medium inside the building and a control module configured to control operation of the heat pump, the water provision system being configured to provide water heated by the thermal energy storage medium to an occupant of the building at one or more water outlets, the method being performed by the control module and comprising: determining, based on performance of the heat pump, an expected start time of a next defrost cycle; and preparing the water provision system before the expected start time of the next defrost cycle.

A hot water supply system 400 comprises a cold water inlet 402 coupled to a valve 404 which determines the degree of flow in a first path 406 and a second path 408. The first path comprises an Energy Storage Arrangement including a heat exchanger 410 which can heat the water from the inlet. The second path includes an electrical heater 422 which can also heat water from the inlet. The two paths each include a respective flow sensor 416, 428 and the paths re-join before providing an outlet 420 from the supply system via a temperature sensor 418. A controller 430 controls the valve 404 and the electrical heater 422 in response to the sensor signals to provide hot water at a desired temperature using a suitable proportion of stored energy and electrical energy. By charging the Energy Storage Arrangement using a heat pump, an economical and responsive hot water supply system is provided.

Provided is an energy bank including a heat exchanger, the energy bank comprising an enclosure, and within the enclosure: an input-side circuit of the heat exchanger for connection to an energy source; an output-side circuit of the heat exchanger for connection to an energy sink; and a phase-change material for the storage of energy; the energy bank including one or more sensors to provide measurement data indicative of the amount of energy stored as latent heat in the phase change material, the energy bank comprising an optical source to launch light into the phase change material, and the one or more sensors includes an optical sensing arrangement to detect light launched from the optical source after the light has passed through the phase change material, wherein the optical source and the optical sensing arrangement is configured to give a graduated measure of a plurality of different energy storage states from empty to full.

Also provided are: an installation including such an energy bank coupled between a heat pump and the hot water system, a processor being configured to make a determination to trigger the starting of the heat pump based on measurement data from the sensors; and a method of controlling a heat pump in such an installation, the method comprising using measurement data from the one or more sensors to trigger the starting of the heat pump.

Provided is a method of signalling a command to a water heating appliance remote from a controllable water outlet fed from the appliance via a water supply installation, the method comprising: monitoring the water supply that feeds the controllable water outlet; detecting a sequence of changes in a property or state of the water supply consequent on operation of the controllable water outlet; correlating the sequence of changes with a stored pattern; detecting a match above a stored threshold; interpreting the match as a command. It is thus possible to manipulate a tap, or other controllable water outlet, to signal to a processor so that the temperature or flow rate of water supplied by the outlet can be increased. Thus a water supply system may have default flow and temperature levels designed for economy and low water usage, but a user can on demand override one or both of these limitations without the necessity of needing to go to the appliance to reset it. The water heating appliance is preferably an instantaneous water heating appliance. Also provided is a water supply installation including a water heating appliance, a controllable water outlet remote from the appliance, a water supply line arranged to feed the controllable water outlet with heated water from the appliance, and at least one sensor to sense a property or state of the water supply line, and a processor coupled to the at least one sensor; the processor being configured to detect a sequence of changes in a property or state of the water supply consequent on operation of the controllable water outlet; correlate the sequence of changes with a stored pattern; detect a match above a stored threshold; interpret the match as a command; and take an action in accordance with the command.

A heater arrangement system for a water provision system for controlling a water supply provided to a water outlet, the water outlet being arranged to provide heated water to a user, the heater arrangement system comprising: a water heating device disposed remotely from the water outlet; and a control unit communicatively coupled to the water heating device, the control unit being configured to: receive a request from a user to enable a reduced temperature water supply mode, which provides for heated water to be supplied to the water outlet at a first temperature for a fixed period of time and then provides for the temperature to be lowered to a second temperature once the fixed time has elapsed; and for a user for which the request has been received, upon detecting that the user has opened the water outlet, providing heated water at the first temperature for a first period of time, then reducing the temperature of the heated water from the first temperature to a second temperature lower than the first temperature after the first period of time has elapsed.

The present disclosure provides a computer-implemented method of predictively preparing a water provision system installed in a building, the water provision system comprising a heat pump configured to transfer thermal energy from outside the building to a thermal energy storage medium inside the building and a control module configured to control operation of the heat pump, the control module having executing thereon a first machine learning algorithm, MLA, having previously been trained to determine a correlation between cold water usage and a subsequent heated water demand, the water provision system being configured to provide water heated by the thermal energy storage medium to an occupant of the building at one or more water outlets, the method being performed by the control module and comprising: receiving first sensor data indicating cold water usage at a first water outlet; determining whether the cold water usage at the first water outlet is correlated to a subsequent heated water demand at a second water outlet by inputting the first sensor data to the first MLA; and upon determining that the cold water usage at the first water outlet is correlated to a subsequent heated water demand at a second water outlet, preparing the water provision system for delivering heated water.

A heater arrangement system for a water provision system for controlling a water supply provided to a water outlet, the water outlet being arranged to provide heated water to a user, the heater arrangement system comprising: a water heating device disposed remotely from the water outlet; and a control unit communicatively coupled to the water heating device, the control unit being configured to a) set a timer to begin counting from an initial time value, upon detection that the water outlet has been opened, and b) initiate a warning if an elapsed time of the timer has passed a first threshold time value.

The present disclosure provides a computer-implemented method of modulating energy consumption by a water provision system, the water provision system comprising a heat pump configured to transfer thermal energy from the surrounding to a thermal energy storage medium and a control module configured to control operation of the water provision system, the water provision pot system being configured to provide water heated by the thermal energy storage medium to a water outlet, the method being performed by the control module and comprising: setting a first temperature for heated water being provided to the water outlet; setting a second temperature for heated water being provided to the water outlet, the second temperature being different from the first temperature; and upon determining that the water outlet is turned on, alternating a temperature of heated water provided to the water outlet between the first temperature and the second temperature.