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.

A water heater includes a heat exchanger. A controllable three-way proportional valve provides a proportionally controllable flow to the hot water inlet of the heat exchanger and a boiler return water outlet. A mixing tank mixes a cold water and a hot water. The mixing tank provides a time delayed mixed water. A temperature sensor is disposed in or on the mixing tank to measure a temperature of the time delayed mixed water to provide a time delayed mixed water temperature. A feedforward control process running on a processor adjusts a proportional operating position of the controllable three-way proportional valve to regulate a temperature of hot water at the hx domestic hot water outlet based on the temperature of the time delayed mixed water temperature. A method for controlling a hot water temperature of a water heater a water heater using a flowmeter based feedforward control are also described.

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 method for starting up a hot ultrapure water production system that produces hot ultrapure water by heating ultrapure water to a supply water temperature, for supplied to a point of use, the method involving: alternately passing heated water and cooled water through a hot ultrapure water pipe through which the hot ultrapure water flows, the heated water being obtained by heating the ultrapure water to a temperature higher than room temperature and the cooled water being obtained by cooling the ultrapure water to a temperature lower than the temperature of the heated water in a range of from room temperature to the supply water temperature.

An installation includes an in-building hot water supply system, a hot water heat pump, an energy storage arrangement containing a mass of phase change material and a heat exchanger coupled between the hot water system and the heat pump, and a processor to provide a signal to the heat pump based on the opening of an outlet of the hot water supply system. The mass of phase change material has enough latent heat capacity to heat to a predetermined temperature a predetermined quantity of water in the interval from the opening of an outlet of the hot water supply system until at least the heat pump begins to heat water in the hot water supply system. Also provided is a method of controlling a heat pump in such an installation.

Provided is a method of controlling a supply of heated water from a source including a heating appliance (301) to a plurality of water outlets (302, 303) remote from the heating appliance, the method comprising: detecting a demand for water from a first water outlet (302), identifying the demand as likely to be associated with the first water outlet (302) and setting to a first target water temperature value, associated with the first outlet, a target water temperature for the temperature at which water is supplied; detecting a demand for water from a second water outlet (303), identifying the demand as likely to be associated with the second water outlet, and resetting to a second target water temperature value, associated with the second outlet, the target water temperature at which water is supplied; wherein the demand is associated with an outlet based on a detected flow characteristic. Also provided is a hot-water supply installation having a plurality of controllable outlets, the installation including: a source of hot-water with an outlet having a controllable outflow temperature; a flow measurement device to provide data on water flow between the source and the plurality of controllable outlets; a temperature sensor to detect the outflow temperature; a memory storing parameters linking flow data to outlet identity, and associating each of the plurality of controllable outlets with a respective target temperature; a processor operatively connected to the memory, the flow measurement device, and the first temperature sensor; the processor being configured: in the event that one of the plurality of controllable outlets is opened, to determine based on a detected flow characteristic which of the plurality of controllable outlets has been opened, and then based on that determination to control the outflow temperature of the source, in accordance with stored parameters for the determined one of the controllable outlets; and in the event that another of the plurality of controllable outlets is opened, to determine which another of the plurality of controllable outlets has been opened, and then based on that determination to control the outflow temperature of the source, in accordance with stored parameters for the determined another of the controllable outlets.

Provided is a heating installation including an energy store including a latent heat energy storage medium, and a heat pump having a defrost cycle, the heating installation including a hot water supply system arranged to supply instantaneous heated water and space heating to a building, and a processor to control the installation. The processor being configured to: control the supply of heat from the heat pump to the latent heat energy storage medium to store heat for heating water and to a heating circuit for providing space heating; and estimate a likelihood of a defrost cycle by the heat pump. In anticipation of an impending defrost cycle, the processor further being configured to control operation of the installation to store additional energy by at least one of: heating the latent heat energy storage medium to a higher level than a level set for anticipated water heating demand alone and/or heating the building and/or circulating heating fluid of the installation to a higher level than a level set for desired building heating; to compensate for an absence of heat from the heat pump during the impending defrost cycle.

A thermostatic device for a pipeline of a sanitary water supply or dispensing system and including a temperature meter which detects the temperature of the sanitary water entering the thermostatic device, a flow regulator which regulates a rate of sanitary water exiting from the device, and a control unit. The flow regulator operates in a first operating mode and a second operating mode. The first operating mode is a steady-state operating mode. The second operating mode is a steady-state setting operating mode in which the flow rate of sanitary water leaving the thermostatic device is a minimum flow rate. The control unit is configured to acquire, receive and/or calculate a reference temperature and arrange the switching of the operating mode when the temperature meter detects a temperature of the sanitary water greater than the reference temperature.