CN117083487A

CN117083487A - Energy storage device and facility

Info

Publication number: CN117083487A
Application number: CN202280013718.7A
Authority: CN
Inventors: 彼得·科诺瓦尔奇克
Original assignee: Octopus Energy Heating Co ltd
Current assignee: Octopus Energy Heating Co ltd
Priority date: 2021-02-07
Filing date: 2022-02-07
Publication date: 2023-11-17

Abstract

There is provided a hot water supply system including: a controllable hot water supply outlet having a given flow rate when fully open; a thermal energy store comprising an energy storage medium comprising a phase change material to store energy as latent heat, the thermal energy store configured to receive energy from a source of renewable energy; renewable energy sources; the hot water supply system is operable to heat water to be supplied to the hot water outlet to a target system supply temperature under control of the processor using a selection of one or more of renewable energy sources, energy from the thermal energy store and optionally an auxiliary water heater located intermediate the thermal energy store and the hot water supply outlet; wherein the thermal energy store has an energy storage capacity, the thermal energy store being sufficient to provide hot water to the hot water outlet at a given flow rate and at a target system supply temperature for a period of at least 8 minutes, preferably at least 10 minutes, when fully energized; wherein the renewable energy source is further configured to provide building heating under control of the processor; the processor is configured to: monitoring the actual demand for hot water from the hot water supply system; predicting a future demand for hot water from the hot water supply system based on the monitored actual demand; pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand; and temporarily transfer heat from the renewable energy source to energize the phase change material rather than providing building heating. Corresponding methods are also provided.

Description

Energy storage device and facility

Technical Field

The present disclosure relates variously to methods, systems, and apparatus for helping customers reduce their energy usage, and in particular to energy storage devices, facilities and systems including such devices, and corresponding methods.

Background

According to instruction 2012/27/EU, the building accounts for 40% of the final energy consumption and CO ₂ 36% of the discharge. The EU Commission 2016 report "Mapping and analyses of the current and future (2020-2030) heating/coolingfuel deployment (fossil/reusables) (current and future (2020-2030) mapping and analysis of heating/cooling fuel deployment (fossil/renewable energy)" concludes that in the EU home, heating and hot water alone account for 79% (192.5 Mtoe) of the total final energy usage. The european union committee also reports that "according to data from the european union statistics office in 2019, about 75% of heating and cooling is still produced from fossil fuels, while only 22% is produced from renewable energy sources. In order to achieve the climate and energy goals of the european union, the heating and cooling industries must drastically reduce energy consumption and reduce the use of fossil fuels. Heat pumps (extracting energy from air, ground or water) have been identified as potentially important factors in solving this problem.

In many countries there are policies and pressures to reduce the carbon footprint. For example, in the united kingdom, the united kingdom government issued a white paper on future residential standards, suggesting that the carbon emissions of new homes were reduced by 75% to 80% from existing levels by 2025. In addition, early 2019 announced that the installation of gas boilers for new homes was prohibited since 2025. It was reported that at the time of filing, 78% of the total energy used for building heating in the uk was from natural gas and 12% from electricity.

In the english country there are a large number of small-sized properties with 2 to 3 bedrooms or less with gas central heating, and most of these properties use so-called hybrid boilers, in which the boiler is used as a instantaneous hot water heater and as a boiler for central heating. Hybrid boilers are popular because they incorporate a small form factor, provide a more or less direct source of "infinite" hot water (20 kW to 35kW output), and do not require hot water storage. Such a boiler can be purchased relatively cheaply from a manufacturer with good reputation. The small form factor and the ability to dispense with hot water storage tanks means that such boilers can be accommodated even in small apartments or small houses-typically mounted on the walls of a kitchen, and that a single person can install a new boiler for one day of work. Therefore, a new hybrid gas boiler can be installed inexpensively. With new gas boilers about to be banned, it would be necessary to provide an alternative heat source to replace the gas-fired hybrid boiler. Furthermore, the previously assembled hybrid boiler will eventually need to be replaced with some alternative.

Although heat pumps have been proposed as reducing dependence on fossil fuels and reducing CO ₂ Potential solutions to emissions, but for many technical, commercial and practical reasons, they are currently unsuitable for replacing the problems of gas boilers in smaller domestic (and small commercial) sites. They are often very large and require large units outside of the property. Thus, they are not easily retrofitted to a property with a typical hybrid boiler. Currently, units capable of providing equivalent output to a typical gas boiler would be expensive and may require a significant amount of power requirements. The cost of these units themselves is not only several times the equivalent gas equivalent, but also its size and complexity mean that the installation is technically complex and therefore expensive. Another technical problem is that heat pumps often require a considerable amount of time to start generating heat in response to demand, may take 30 seconds of self-test time, and then require some time to heat-thus, there is a delay of 1 minute or more between requesting hot water and delivering hot water. For this reason, renewable solutions that attempt to use heat pumps and/or solar energy are generally applicable to large real estate (with space requirements, heat loss and Legionella risk) with hot water storage tank space.

Accordingly, there is a need to provide a solution to the problem of finding a suitable technology to replace gas-fired hybrid boilers, especially for smaller residential dwellings.

More generally, further developments are sought to expand the applicability of heat pumps. Aspects of the present disclosure provide solutions to these long felt needs.

Other concerns also stem from the need to reduce the amount of carbon dioxide released into the atmosphere and more generally the need to reduce the amount of energy wasted by the home.

Disclosure of Invention

In a first aspect, there is provided a hot water supply system comprising:

a controllable hot water supply outlet having a given flow rate when fully open; a thermal energy store comprising an energy storage medium comprising a phase change material storing energy as latent heat, the thermal energy store configured to receive energy from a source of renewable energy;

renewable energy sources; the hot water supply system is operable to heat water to be supplied to the hot water outlet to a target system supply temperature under control of the processor using a selection of one or more of renewable energy sources, energy from the thermal energy store and optionally an auxiliary water heater located intermediate the thermal energy store and the hot water supply outlet; wherein the thermal energy store has an energy storage capacity, the thermal energy store being sufficient to provide hot water to the hot water outlet at a given flow rate and at a target system supply temperature for a period of at least 8 minutes, preferably at least 10 minutes, when fully energized; wherein the renewable energy source is further configured to provide building heating under control of the processor; the processor is configured to: monitoring the actual demand for hot water from the hot water supply system; predicting a future demand for hot water from the hot water supply system based on the monitored actual demand; pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand; and transferring heat from the renewable energy source to energize the phase change material instead of providing building heating.

With such a system, energy can be utilized more efficiently by avoiding the need to invoke, for example, an auxiliary water heater. It may also be easier to rely entirely or to a greater extent on renewable energy sources and to reduce reliance on fossil fuels. Further energy savings may be achieved by configuring the renewable energy source to provide building heating under control of the processor, and configuring the processor to transfer heat from the renewable energy source to energize the phase change material instead of providing building heating. For example, if the heat pump is said to be used to provide building heating, such as space heating, it may be more energy efficient, cheaper or "more environmentally friendly" to temporarily transfer heat from the heat pump to the PCM rather than using the heat to heat the building.

The source of renewable energy may be a solar water heating device or a heat pump. The described hot water supply system facilitates the use of heat pumps as the primary energy source, particularly for smaller domestic facilities as previously described, but also provides a method of integrating PCM capable storage into solar water heating devices and potentially reduces reliance on networked energy supplies that may come from fossil fuels.

The renewable energy source may be a solar water heating device or a heat pump.

The source of renewable energy from which the thermal energy store is configured to receive energy may be a renewable energy source.

The energy storage may comprise an electrical heating element to enable energisation of the phase change material using heat from the electrical heating element. This is especially beneficial where the processor is able to take advantage of the low power supply price, but also increases the flexibility when renewable energy sources are not available.

The processor may be configured to decide when and how much to energize the PCM based on the predicted future demand and taking into account the cost of the energy to be used. While users may be enthusiastic to rely on renewable energy sources rather than fossil fuels, they may also be interested in the monetary cost of operating a water heating system—sometimes their interest in monetary cost may dominate.

The thermal energy store optionally comprises sufficient phase change material to store between 5 and 10 millijoules of latent heat. Since the energy storage capacity is within this range, it should be possible to keep the physical size of the energy storage within manageable limits (e.g., so that it can be accommodated within a typical small residence) while still being able to store enough heat as latent heat to meet the expected demand of even a substantial amount of hot water.

The processor may be configured to use data from the one or more occupancy sensors to predict future demands of hot water from the hot water supply system. By taking into account the current occupancy, the processor may better estimate future demand, for example by correcting the initial predictions up or down based on historical data of time/date/season.

The processor may be configured to use the forecasted weather information to predict future demands for hot water from the hot water supply system. For example, this may include a forecast demand for hot water during the summer months when the weather is hot than when the weather is cold, as historically, a household may shower more when the weather is hot than when the weather is cold.

The processor may be configured to use data from one or more ambient temperature sensors to predict future demands of hot water from the hot water supply system. Knowledge of the actual ambient temperature may enable better predictions to be made than might be possible, for example, when considering weather forecast data, as the actual ambient climate conditions may differ significantly from the weather forecast data (the weather forecast data will tend to be at most regional rather than location specific).

The hot water supply system may serve a single household and the processor may be configured to use calendar and schedule information of household members to predict future demands of hot water from the hot water supply system. By enabling the processor to use calendar and calendar information, more intelligent predictions are more likely, and thus more near optimal energy use may be achieved.

According to a second aspect, there is provided a method of controlling a heating appliance in a hot water supply system having a controllable hot water supply outlet having a given flow rate when fully open, and comprising: a thermal energy store comprising an energy storage medium comprising a phase change material to store energy as latent heat, the thermal energy store configured to receive energy from a source of renewable energy; renewable energy sources; the hot water supply system is operable to heat water to be supplied to the hot water outlet to a target system supply temperature under control of the processor using a selection of one or more of renewable energy sources, energy from the thermal energy store and optionally an auxiliary water heater located intermediate the thermal energy store and the hot water supply outlet; wherein the thermal energy store has an energy storage capacity, the thermal energy store being sufficient to provide hot water to the hot water outlet at a given flow rate and at a target system supply temperature for a period of at least 8 minutes, preferably at least 10 minutes, when fully energized; wherein the renewable energy source is further configured to provide building heating under control of the processor, the method comprising: monitoring the actual demand for hot water from the hot water supply system; predicting a future demand for hot water from the hot water supply system based on the monitored actual demand; and pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand; and is also provided with

The processor transfers heat from the renewable energy source to energize the phase change material rather than providing building heating.

The method may further include using an electrical heating element within the energy storage to energize the phase change material with heat from the electrical heating element.

The method may further include deciding when and how much to energize the PCM based on the predicted future demand and the cost of the energy to be used in consideration.

The method may further include using data from the one or more occupancy sensors to predict future demands of hot water from the hot water supply system.

The method may further include using the forecasted weather information to predict a future demand for hot water from the hot water supply system.

The method may further include using data from one or more ambient temperature sensors to predict future demands of hot water from the hot water supply system.

In a method according to any variation of the second aspect, the hot water supply system may serve a single household, and the method may further comprise using calendar and schedule information of members of the household to predict future demands of hot water from the hot water supply system.

In a method according to any variant of the second aspect, the thermal energy store comprises sufficient phase change material to store between 5 and 10 millijoules of latent heat.

Drawings

Various aspects of embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing an energy bank including a phase change material and a heat exchanger coupled to a heat pump energy source, the energy bank including one or more sensors to provide measurement data indicative of an amount of energy stored as latent heat in the phase change material;

FIG. 2 is a high-level flow chart of a method performed by a facility including an energy store, such as the energy store of FIG. 1;

FIG. 3 is a high-level flow chart of another method performed by an energy store, such as the energy store of FIG. 1;

FIG. 4 is a flow chart of another method performed by an energy store, such as the energy store of FIG. 1;

FIG. 5 is a flow chart of another method performed by an energy store, such as the energy store of FIG. 1;

FIG. 6 is a schematic diagram illustrating an indoor water supply according to an aspect of the present disclosure; and

fig. 7 is a schematic diagram illustrating a possible arrangement of components of an interface unit incorporating an energy bank according to an aspect of the present disclosure.

Detailed Description

One of the many limitations on the applicability of heat pumps is their relatively limited ability to meet hot water demands, at least compared to transient gas and electric water heaters, such as hybrid boilers, and their advantages as space heating heat sources. As previously mentioned, for a typical medium-scale residence in the uk, the space heating requirement is generally as low as 6kW, whereas even in a common one-or two-bed apartment, a gas-fired hybrid boiler is generally capable of providing 20kW to 30kW of instant hot water. In europe, a space heating demand of 6kW can be easily achieved even with an air source heat pump, but units that can provide 20kW to 30kW would be unacceptably large and expensive. The heat pump is further limited in its application to domestic hot water supply, i.e. there is a long lag between the heat pump receiving the start signal and the hot water actually supplied by the heat pump. Typically, this hysteresis is in excess of one minute, and sometimes as much as two minutes or more. While at first glance this appears to be unimportant, when one realizes something like washing hands-one of the most common uses of hot water in a home environment-the average time that a hot water tap is running is between 30 seconds and 1 minute-then the heat pump has a significant obstacle to overcome.

Furthermore, heat pumps are generally not able to support repeated starts without significant delay between these starts, and if the start request follows too fast during operation, their internal processor will not take action on the start request. Of course, this means that in addition to the unavoidable hysteresis from sending a start request to delivering heat discussed previously, there may sometimes be a need for heat from the heat pump and a start request is sent, but no heat is available.

Generally, these two problems can be solved by storing the hot water in a hot water storage tank so that it is provided on demand. But this solution is unattractive for smaller houses, such as the british single, two and three bed houses currently using gas-fired hybrid boilers, which are almost universally installed without external hot water storage tanks.

Thermal energy storage is a technology that has the potential to increase the applicability of heat pumps to demands, especially domestic heat demands, but not with hot water storage as a jeopardy.

An alternative to such thermal energy storage is the use of Phase Change Materials (PCM). As the name suggests, phase change materials are materials that exhibit thermally induced phase changes: heating the PCM to its phase transition temperature results in energy being stored in the form of latent heat (rather than sensible heat). Many different PCMs are known, the choice of any particular application depending on, among other things, the desired operating temperature, cost constraints, health and safety constraints (considering toxicity, reactivity, flammability, stability, etc. of the PCM, and these constraints on the PCM to accommodate the desired materials, etc.). By a suitable choice of PCM, the thermal energy storage device can be designed such that energy from the heat pump can be used for instantaneous heating of the water of the (domestic) hot water system, thus helping to solve the problem of slow start-up inherent in the use of heat pumps, without the need for a bulky hot water tank.

We will now introduce and describe an energy storage device based on the use of PCM, which is particularly suitable for installations using heat pumps to heat water in a hot water supply. Such an energy storage device may include a heat exchanger including an enclosure, and within the enclosure: an input side loop for connection to an energy source such as a heat pump, an output side loop for connection to an energy sink such as a hot water supply facility, and a phase change material for storing energy.

The input side loop receives liquid heated by a heat source, in our example a heat pump, but could also be a solar water heater, and if the liquid is hotter than the material in the heat exchanger, energy is transferred from the liquid to the material in the heat exchanger. Likewise, energy from the material in the heat exchanger is transferred to the liquid in the output side loop, provided that the liquid is colder than the material in the heat exchanger. Of course, if no fluid flows through the output side loop, the energy transferred from the heat exchanger is limited, so that a large part of the input energy remains in the heat exchanger. In our example, the heat exchanger contains a phase change material, such as paraffin or salt hydrate (examples of suitable materials will be discussed later), so that the input energy is mostly transferred to the PCM. By appropriate selection of the phase change material and heat pump operating temperature, energy from the heat pump can be used as an energy "sink" denoted by PCM. Alternatively, the energy supply from the heat pump may be supplemented by including one or more electrical heating elements in the heat exchanger, the heating elements being controlled by the processor of the system and being used, for example, when low cost electricity prices are applicable for the power supply, or local or domestic power production, such as from wind, hydraulic or photovoltaic power generation, can provide "inexpensive" energy, for example, when future hot water demand is expected or desired.

In a hot water supply system comprising such a thermal energy store it is useful to predict future demands for hot water from the hot water supply system and to pre-energize the thermal energy store based on such predictions so that sufficient energy will be stored in the thermal energy store to meet the predicted demands. By doing so, the need to invoke other energy sources, such as additional transient heat sources using energy supplied from a network supply using fossil fuels, can be avoided. The energy storage may also be pre-energized with less energy than would be available if the need for hot water was ultimately achieved.

We will now describe a hot water supply system comprising a thermal energy store containing an energy storage medium comprising a phase change material to store energy as latent heat, the thermal energy store being configured to receive energy from a source of renewable energy, and the hot water supply system comprising a processor configured to predict a future demand for hot water from the hot water supply system based on monitored actual demand, and pre-energize the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand.

Fig. 1 schematically illustrates a thermal energy store or energy reservoir 10 comprising a heat exchanger, the energy reservoir comprising an enclosure 12. Within enclosure 12 is a source of heat exchanger for connection to renewable energy, here shown as an input side loop 14 of heat pump 16, and a heat exchanger for connection to an energy sink, here shown as an output side loop 18 of a hot water supply system connected to a cold water supply 20 and including one or more outlets 22. Each of the outlets 22 has a given flow rate when fully open. Such a given flow rate may be in the range of 5 to 15 litres per minute, say 7, 10, 12 or 15 litres per minute.

Within enclosure 12 is a phase change material for storing energy using the latent heat of the phase change material. The thermal energy store has an energy storage capacity that, when fully energized, is sufficient to provide an effectively long period of hot water to one or more of the hot water outlets 22 at a given flow rate and at a target system supply temperature. The period of time will typically exceed 5 minutes, preferably at least 7 minutes or 8 minutes, and preferably at least 10 minutes, 12 minutes or 15 minutes. Preferably, the thermal energy store comprises sufficient phase change material to store between 5 and 10 millijoules of latent heat.

The energy bank 10 preferably also includes one or more condition sensors 24 to provide measurements indicative of PCM conditions. For example, one or more of the condition sensors 24 may be a pressure sensor to measure pressure within the enclosure. When designing a system using a phase change material, one property of the phase change material has to be considered as a volume change occurring upon phase-to-phase conversion, such as expansion upon phase change between liquid and solid, and contraction upon phase change between solid and liquid. Typically, the volume change is about 10%. Such volume changes may be considered a disadvantage, which has to be accommodated by careful design of the enclosure for containing the phase change material, but the volume changes may also be used actively. By including one or more sensors to provide a measurement of the pressure within the PCM enclosure, data may be provided to the processor from which the processor may determine the state of the phase change material. For example, the processor may be capable of determining an energy storage value of the phase change material.

In addition to, or as an alternative to, measuring the pressure within the enclosure as a means of determining the energy storage of the phase change material, a change in optical or acoustic properties that occurs in the PCM upon phase change may be used. Examples of these alternative methods will be described later, but first we will consider using pressure sensing as a means of collecting information about the energy storage state of the PCM.

Preferably, the enclosure further comprises one or more temperature sensors 26 to measure the temperature within the PCM. If multiple temperature sensors are preferably provided within the PCM, these are preferably spaced apart from the structure of the input and output circuits of the heat exchanger and are suitably spaced apart within the PCM to obtain a good "image" of the PCM state.

The energy bank 10 has an associated energy controller 28 that includes a processor 30. The controller may be integrated into the energy reservoir 10, but is more typically installed separately. The controller 28 may also be provided with a user interface module 31 as an integrated or separate unit or as a unit that may be detachably mounted to the body comprising the controller 28. The user interface module 31 typically comprises a display panel and a keypad, for example in the form of a touch sensitive display. If the user interface module 31 is separate or separable from the controller 28, the user interface module 31 preferably includes wireless communication capabilities to enable the processor 30 of the controller 28 and the user interface module to communicate with each other. The user interface module 31 is used to display system status information, messages, advice and warnings to the user and to receive user inputs and user commands such as start and stop instructions, temperature settings, system overrides, etc.

One or more status sensors are coupled to the processor 30, and one or more temperature sensors 26, if present, are also coupled to the processor 30. The processor 30 is also coupled to a processor/controller 32 in the heat pump 16 by a wired connection or wirelessly using associated transceivers 34 and 36 or by both wired and wireless connections. In this way, the system controller 28 is able to send instructions, such as start and stop instructions, to the controller 32 of the heat pump 16. In the same manner, the processor 30 is also capable of receiving information such as status updates, temperature information, etc. from the controller 32 of the heat pump 16.

The hot water supply facility also includes one or more flow sensors 38 that measure flow in the hot water supply system. As shown, such flow sensors may be provided on the cold water supply 20 of the system and/or between the outputs of the output side circuits 18 of the heat exchanger. Optionally, one or more pressure sensors may also be included in the hot water supply system, and the one or more pressure sensors may also be disposed upstream of the heat exchanger/energy reservoir, and/or downstream of the heat exchanger/energy reservoir, such as side-by-side with one or more of the one or more flow sensors 38. The or each flow sensor, the or each temperature sensor and the or each pressure sensor are coupled to the processor 30 of the system controller 28 by either or both of a wired or wireless connection, for example using one or more wireless transmitters or transceivers 40. Depending on one or more properties of the various sensors 24, 26, and 38, they may also be interrogated by the processor 30 of the system controller 28.

Optionally, as shown, the hot water supply facility further comprises a cold water mixing valve 42 under control of the processor 30 for mixing cold water from the cold water supply with hot water from the thermal energy store 10. In this way, hot water may be delivered at a target system supply temperature controlled by the processor 30. The thermometer 26 is disposed at the output of the valve 42 or immediately downstream of the valve 42 and is coupled to the processor 30 so that the processor can monitor the temperature of the water supplied by the valve and adjust the temperature accordingly. Preferably, as shown, the facility also includes an auxiliary instantaneous water heater 44 located intermediate the energy storage 10 and the mixing valve 42 under the control of the processor 30 so that water can be heated or heat increased even when the energy storage 10 is depleted and even when the heat pump 16 is not able to provide heat. The auxiliary instant water heater 44 is preferably an electric heater using induction heating or resistance heating, although other energy sources, such as gas, may be used instead.

Alternatively, as shown, the energy bank 10 may include an electrical heating element 48 within the enclosure 12, the electrical heating element 48 being controlled by the processor 30 of the system controller 28 and sometimes being used as an alternative to the heat pump 16 to re-energize the energy bank. Optionally, the electrical heating element 48 is connected to a renewable energy source, such as a local or household electrical power supply from a photovoltaic array or wind or water turbine.

The hot water supply system is operable to heat water to be supplied to the one or more hot water outlets 22 to a target system supply temperature using a selection of one or more of the renewable energy source 16, energy from the thermal energy store 10 and the optional auxiliary instantaneous water heater 44 under control of the processor 30.

The processor 30 is configured to monitor the actual demand of hot water from the hot water supply system. For example, the time, duration, flow rate and energy content of the hot water supplied are recorded. The processor 30 is further configured to predict a future demand for hot water from the hot water supply system based on the monitored actual demand. The processor 30 may also be configured to use calendar and schedule information of members of a household served by the hot water supply system when predicting future demand for hot water from the hot water supply system, for example, if the hot water supply system serves a single household.

In the case where the source of renewable energy and/or renewable energy source is one or more solar water heating facilities, the processor may be arranged to predict an optimal period of time for invoking energy from the solar water heating facilities. Typically, such facilities include some form of energy storage, often in the form of a hot water reservoir-and therefore it is not uncommon to find such facilities in small homes that are typically serviced by gas mixing boilers. But in larger homes and some smaller homes such facilities are occasionally used and it is envisaged that energy may be transferred from the hot water store or that the heat system fluid from the solar facility (which is typically fed only to the heat exchanger in the hot water store) is used to energize the PCM under the control of the processor 30.

The processor may also be configured to predict future demands using knowledge about occupancy levels, e.g., knowledge about occupancy levels from one or more occupancy sensors (motion sensors such as acoustic or PIR sensors, activity sensors, electrical activity sensors, etc.), smart device data such as "smart device" data from "smart speakers" or from "smart home" facilities or applications.

Preferably, the processor is configured to use the forecasted weather information to predict future demands of hot water from the hot water supply system.

Preferably, the processor is configured to use data from one or more ambient temperature sensors to predict future demands of hot water from the hot water supply system.

Based on the predicted future demand for hot water, the processor 30 is configured to pre-energize the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand.

Preferably, the processor has access to data regarding energy costs, including price data for energy supplied by the utility network, and costs of running a source of renewable energy (e.g., a heat pump). Preferably, the processor has access to one or more data networks, such as the internet, and/or databases of utility providers. Preferably, the processor is configured to decide when and how much to energize the PCM based on the predicted future demand and taking into account the cost of the energy to be used. The processor 30 may be provided with a machine learning algorithm to learn the behavior of the home and support the prediction of demand.

In fig. 1, the heat pump 16 is shown to supply heat only to the energy store 10, and not directly to the hot water supply system. This is the preferred arrangement where fluid flows between the heat exchanger in the heat pump and the heat exchange coil 14 in the energy store. It will be appreciated that the heat exchanger in the heat pump may be supplied by the water to be heated for the hot water supply system and that the water thus heated may be fed into the hot water supply system bypassing the energy store-the mixing valve is optionally inserted into the hot water supply system downstream of the energy store 10 and is preferably located between the energy store and the mixing valve 42 and in particular between the energy store and the auxiliary instantaneous water heater 44, if present.

Fig. 1 is only a schematic view and only shows the connection of the heat pump to the hot water supply. It should be appreciated that space heating as well as hot water is required in many parts of the world. Therefore, typically, the heat pump 16 will also be used to provide space heating. An exemplary arrangement in which the heat pump both provides space heating and works with an energy reservoir for hot water heating will be described later in the present application. For ease of description, the following description of a method of operating an energy bank according to an aspect of the present application, such as the one shown in fig. 1, is equally applicable to an energy bank facility, whether or not the associated heat pump provides space/building heating. Preferably, in such an arrangement, the processor is configured to transfer heat from the renewable energy source to energize the phase change material, rather than providing space/building heating.

It will be appreciated that the various forms of apparatus previously described constitute a hot water supply system having one or more controllable hot water supply outlets each having a given flow rate when fully open, and that the hot water supply system comprises: a thermal energy store comprising an energy storage medium comprising a phase change material to store energy as latent heat, the thermal energy store configured to receive energy from a source of renewable energy; and renewable energy sources. And in various forms, the hot water supply systems are operable to heat water to be supplied to the hot water outlet to a target system supply temperature under control of the processor using a renewable energy source and a selection of one or more of the energy from the thermal energy store and optionally auxiliary instantaneous water heater 44; the thermal energy store has an energy storage capacity that, when fully energized, is sufficient to provide an effectively long period of hot water to the hot water outlet at a given flow rate and at a target system supply temperature. The period of time will typically exceed 5 minutes, preferably at least 7 minutes or 8 minutes, and preferably at least 10 minutes, 12 minutes or 15 minutes.

The target system supply temperature will typically be in the range of 38 degrees celsius to 50 degrees celsius, but may sometimes be increased up to 60 degrees celsius or higher, for example up to 60 degrees celsius or higher during a periodic sterilization cycle, to kill legionella bacteria, preferably under the control of the processor 30.

Such a facility and apparatus may be arranged to provide a method of controlling a heating appliance in a hot water supply system, the method comprising: monitoring an actual demand for hot water from a hot water supply system; predicting a future demand for hot water from the hot water supply system based on the monitored actual demand; and pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand.

A method of controlling a facility according to an aspect of the present invention will now be described with reference to fig. 2. Fig. 2 is a simplified flow diagram illustrating various actions performed by a processor associated with a facility according to any variation of the third or fourth aspects of the present invention.

The method begins at 220, where a determination of the amount of energy stored as latent heat in the phase change material is generated based on information from one or more of the state sensors 24.

Then, at step 230, based at least in part on the determination, the processor decides whether to provide an activation signal to the heat pump. In addition to the state of the PCM, various factors that may be considered by the processor will be introduced and discussed later in this application.

Fig. 3 is another simplified flow diagram illustrating various actions performed by a processor associated with a facility according to any variation of the third or fourth aspects of the present invention.

The method begins at 300, where a processor receives a signal indicating that an outlet of a hot water supply system is open. The signal may be, for example, from a flow sensor 38 in the hot water supply system, or from a flow sensor 38 in the cold water supplied to the hot water system. At 302, the processor estimates a demand for hot water from the hot water supply system based on, for example, an identification or type of outlet that has been opened or based on an instantaneous flow rate. The processor compares the estimated demand with a first threshold demand level. If the estimated demand is above the first threshold demand level, the processor generates a heat pump start message at 304. If the estimated demand is below a first threshold demand level, the processor compares the estimated demand to a second threshold demand level that is lower than the first threshold demand level. If the estimated demand is below the second threshold demand level, the processor determines that a heat pump start message is not generated at 306.

If the estimated demand is between the first threshold demand level and the second threshold demand level, then at 308, the processor considers the energy storage level of the energy bank. This may involve the processor re-establishing the energy storage level of the energy bank, or the processor may use recently generated information about the energy storage level of the energy bank.

If it is determined that the energy storage level for the energy bank is greater than the first energy storage level threshold, the processor determines that a heat pump activation message is not generated at 304. Conversely, if the determination of the energy storage level for the energy bank is less than the first energy storage level threshold, the processor determines to generate a heat pump activation message at 306.

A method of controlling a facility according to an aspect of the present invention will now be described with reference to fig. 4. FIG. 4 is a simplified flow diagram illustrating various actions performed by a processor associated with an energy store, such as the energy store illustrated in FIG. 1. The process begins at step 400 when the processor 30 detects the flow of water in the hot water supply system. The detection is preferably based on data from a flow sensor, such as flow sensor 38 of fig. 1, but may alternatively be based on data from a pressure sensor in the hot water supply system. The relevant sensor may be configured to continuously provide measurement data to the processor 30, or may be configured to report only changes in measurement data, or the processor may continuously or periodically (e.g., at least once per second) read the relevant sensor.

At step 402, processor 30 determines whether the flow rate indicated by the data from the sensor is indicative of high flow or low flow, for example, above or below a particular threshold. The processor may use more than one threshold to classify the flow rate as high, medium or low, or the categories may include very high, medium and low. Categories of very low or very small flows may also exist. The processor 30 may also be provided with information (e.g., in the form of a database, model, or MLA) regarding the flow rate and flow characteristics for each of the outlets or outlet types of the outlets 22 of the hot water supply system (e.g., using techniques such as those described later in this patent application), the processor then characterizing the detected flow rates as being associated with a particular outlet or type of outlet 22 (e.g., shower outlet, bathtub outlet, kitchen sink outlet, washbasin outlet).

If it is determined 403 that the demand for hot water is indicated, the processor then considers the status of the power pack 10 based on at least the information from the status sensor 24 in step 404. The processor 30 may interrogate the state sensor 24 (e.g., a pressure sensor) at this stage, or may examine the recently updated energy bank state, in either case determining whether the energy bank is in a high energy state 405 (where a large portion of the potential latent heat capacity of the energy bank is available) or in a low energy state 406 (where a small portion of the potential latent heat capacity of the energy bank is available). The processor may also consider information from the temperature sensor 26, for example to consider the sensible energy stored in the energy reservoir 10. If the processor 30 determines a high energy state, the processor determines not to send a start-up instruction to the heat pump and the process terminates at 407. If the processor 30 determines a low energy state, the processor may then determine to send a start instruction 422 to the heat pump at 406.

If it is determined 408 that the demand for hot water is indicated, the processor may then consider the status of the power pack 10 based on at least the information from the status sensor 24 in step 409. The processor 30 may interrogate the state sensor 24 at this stage, or may examine the most recently updated energy bank state, in either case determining whether the energy bank is in the high energy state 410 (where a large portion of the potential latent capacity of the energy bank is available) or in the low energy state 412 (where a small portion of the potential latent capacity of the energy bank is available).

The processor may also consider information from the temperature sensor 26, for example to consider the sensible energy stored in the energy reservoir 10. If the processor 30 determines a high energy state 410, the processor optionally determines a predicted hot water demand in step 414. The processor may alternatively be configured to issue an instruction to start the heat pump at 422 (as indicated by cross-hatched arrow 411) based simply on the magnitude of the flow rate without predicting the hot water demand.

In step 414, the processor 30 may predict the hot water demand taking into account the determined identity (i.e., the particular outlet) or water outlet type. For example, if the outlet is identified as a kitchen sink outlet, the faucet will be unlikely to operate for more than 30 seconds to one minute. However, if the outlet is a bathtub tap, the tap may remain open for a few minutes in the event that about 120 to 150 litres of hot water are required.

In the first case, the processor 30 will determine not to send an activation signal to the heat pump at 416, but will instead end the process, or more preferably continue monitoring the flow rate at 418 to see how long the flow continues. If the flow stops for the predicted time, the process ends at 420, but if the flow of water continues longer than predicted, the processor returns to step 409 at 419. In the second case, the processor 30 will determine at 421 to send an activation signal 422 to the heat pump (and arrow 411 indicates a decision to activate the heat pump based simply on the instantaneous flow rate or outlet identification (or outlet type) as associated with drawing a significant amount of hot water from the hot water supply system).

After starting the heat pump at 422 (from the determination at 406 or 421), the processor 30 continues to monitor (periodically or continuously) the power pack state at 424 until the state reaches some threshold level 425 that is enabled, at which the processor sends a signal to shut down 426 the heat pump.

Fig. 5 is another simplified flowchart illustrating various actions performed by a processor associated with an energy store, such as, for example, processor 30 of fig. 1. Unlike the method described with reference to fig. 4, the method of fig. 5 does not depend on the detection of the hot water demand, i.e. on the opening of the outlet of the hot water system. In general, FIG. 5 illustrates a method of controlling a facility, the method including generating a determination of an amount of energy stored as latent heat in a phase change material; and deciding whether to provide a start signal to the heat pump based on the determination. Although, as will be seen, an optional but preferred step may occur between the step of generating a determination of the amount of energy stored as latent heat in the phase change material and the step of deciding whether to provide an activation signal to the heat pump based on the determination.

The method begins at step 500, where the processor 30 estimates the amount of energy stored as latent heat in the phase change material of the energy bank 10. The amount of heat may be an absolute amount in kilojoules, but may also simply be a measure of the proportion of potential latent heat capacity currently available. In other words, the processor may effectively determine the proportion of phase change material still in the phase having the higher energy state. Thus, for example, if the phase change material is paraffin wax having a phase change from liquid to solid, the liquid phase is a higher energy phase incorporating latent heat of fusion, and the solid phase is a lower energy phase where the latent heat of fusion has been depleted upon solidification.

If the processor determines that the amount of energy stored as latent heat is sufficient 502, i.e., exceeds some predetermined threshold, the method moves to step 504, at which step 504 the process stops and the processor waits for the next check 500.

If the processor determines that the amount of energy stored as latent heat is insufficient 506, i.e., at or below some predetermined threshold, the method moves to step 508. At step 508, the processor determines a likelihood that a substantial amount of hot water is needed in the upcoming time period (e.g., in the next half hour, one hour, 2 hours, 3 hours, or 4 hours). The time period considered is a factor of the heat capacity of the energy reservoir, the determined size of the energy shortage and the capacity of the heat pump for re-energizing the energy reservoir in these cases. It will be appreciated that the period of demand considered should be large enough to enable the heat pump to re-energize the energy bank sufficiently within that period so that the energy bank will be optimally energized (possibly fully energized) to be able to cope with the predicted or anticipated demand. In contrast, a heat pump should not be used to re-energize an energy bank too long before the expected/predicted energy demand, so that the energy bank will lose a large amount of energy by radiation, conduction or convection.

The processor may rely on a database, model, calendar or schedule, and any and all of these may include learned behavior and behavior patterns as well as predetermined events (such as predetermined absence or events predetermined for some other location). The processor may also access local weather reports, for example provided (pushed or received) via the internet or in a radio transmission device and/or an external thermometer.

If the processor determines 510 that there is a low likelihood of significant hot water demand within the period, the method moves to step 504 where the process stops and the processor waits for the next check 500.

If the processor determines 512 that there is a high likelihood of significant hot water demand during the period, the method moves to step 514 where the heat pump is turned on at step 514: for example, the processor 30 sends instructions to the heat pump 16 causing the heat pump processor 32 to enable a heat pump start-up procedure after which the heat pump begins to supply heat to the input side of the heat exchanger, thereby delivering energy into the phase change material. The processor then repeatedly determines whether there is now sufficient energy stored in the energy store as latent heat of the phase change material in step 516. Once the processor has determined 518 that enough energy is now stored in the energy store as latent heat of the phase change material, the method moves to step 520 and the heat pump is turned off, for example by the processor 30 sending an appropriate command. The method continues as long as the processor determines 522 that the stored energy is insufficient.

Referring back to fig. 1, instead of or in addition to providing one or more condition sensors 24 to measure pressure within the enclosure, other types of sensors may be provided to measure optical properties of the PCM, such as transparency, absorption, refraction, refractive index, as various of these properties change as a function of phase changes in the PCM. In addition, various ones of these characteristics may exhibit wavelength dependence that changes with changes in phase.

Thus, the energy reservoir may further comprise one or more light sources to emit light into the phase change material, and the one or more state sensors 24 may comprise optical sensing means to detect the light emitted from the light sources after said light has passed through the phase change material. The change between the phases of the phase change material causes a reversible change in the optical properties of the phase change material, and thus observing the optical properties of the PCM may be used to gather information about the state of the PCM. Preferably, the optical properties of the PCM are observed in several areas of the PCM, and preferably in different directions within the material. For example, the light source and sensor may be arranged such that light from the light source passes longitudinally through the PCM at one or more locations, and other light sources and sensors may be arranged such that light from the light source passes laterally through the PCM (through width and/or through thickness) at one or more locations and in one or more directions.

The light sources may be controllable to produce different colors of light, and the optical sensing device may be configured to detect at least some of the different colors. By selecting the appropriate color of the light based on the particular PCM selected for any application, the degree to which the phase of the PCM has changed can be more accurately determined.

Preferably, the light source comprises a plurality of individually activatable devices.

Coupling the optical sensing device to a processor configured to estimate an amount of energy stored in the phase change material based on information received from the optical sensing device provides a way to determine the amount of energy stored as latent heat within the PCM, and this information can be used to control the heat pump. In particular, such information may enable a more efficient and more appropriate use of the heat pump in energizing the PCM energy bank.

As another option, the one or more status sensors 24 to provide measurement data indicative of the amount of energy stored as latent heat in the phase change material may include a sound source configured to emit sound into the phase change material and an acoustic sensing device to detect sound emitted from the sound source after the sound has passed through the phase change material. The change between the phases of the phase change material causes a reversible change in the sound absorption properties of the phase change material, and thus observing the acoustic properties of the PCM may be used to collect information about the state of the PCM. The sound source may be configured to generate ultrasonic waves.

Fig. 6 schematically illustrates a water supply facility 100 within a building, the water supply facility 100 having a plurality of controllable water outlets (various faucets and showers, which will be described more fully below), a water supply 105, and at least one flow measurement device 110 and at least one flow regulator 115 and a processor 120 operatively connected to the at least one flow measurement device 110 and the at least one flow regulator 115 in a water flow path between the water supply 105 and the plurality of controllable water outlets. The illustrated water supply facility represents a residence having a main bathroom 121, a first suite of shower stalls 122, a second suite of shower stalls 123, a lavatory 124, and a kitchen 125. The main bathroom and the first suite of shower bathrooms may be located in one floor of the residence, while the lavatory, the second suite of shower bathrooms and the kitchen may be located in another floor of the residence.

In this case, as shown, it may be convenient to have two separate circuits 130 and 131 to supply water to each outlet.

The main bathroom 121 is shown to include a shower outlet 135, a bathtub tap or faucet 136, and a tap 137 for a sink. The suite shower enclosures 122 and 123 also include a shower outlet 135 and a faucet 137 for the sink. Instead, the lavatory includes only a lavatory (not shown) and a basin 138 with a faucet. Finally, the kitchen has a sink with a tap 139.

A processor or system controller 140 having associated memory 141 is coupled to the at least one flow measurement device 110 and the at least one flow regulator 115. It will be appreciated that each of the two circuits 130 and 131 is provided with a respective flow measurement device 110 and flow regulator 115. The processor is also optionally connected to one or more temperature sensors 143, one for each of the loops 130 and 131. As previously described, the processor may be associated with an energy store.

The processor is also coupled to an RF transceiver 142 comprising at least one RF transmitter and at least one RF receiver for bi-directional communication via Wi-Fi, bluetooth, etc., and preferably also to the internet 144 for connection to a server or central station 145, and optionally to a cellular radio network (such as LTE, UMTS, 4G, 5G, etc.). By means of the RF transceiver 142 and/or a connection to the internet, the processor 140 can communicate with a mobile device 150, which may be, for example, a smart phone or tablet, for use by an installation engineer in mapping water supply facilities within a building. The mobile device 150 includes software, such as a specific application program, that cooperates with corresponding software in the system controller 140 and potentially within the server 145 to facilitate mapping methods according to embodiments of the present invention, and in particular to synchronize actions taken by engineers with the clocks of the system controller 140/server 145. The memory 141 contains code to enable the processor to perform a method of mapping water supply facility processors within a building, for example, during a process of commissioning a new facility. For descriptive purposes, consider that fig. 6 shows a hot water supply facility, however it may also be a cold water supply facility.

During the commissioning process, the processor/system controller 140 would require the engineer to define all hot water outlets (hot water outlets for e.g. faucets, showers, bathtubs, kitchens). The system controller would require an engineer to fully open each of the outlets (faucet, shower outlet, etc.) and would monitor the resulting water flow by means of the associated flow measurement device 110. During this process, the associated flow measurement device 110 will measure the water flow and the processor will receive this data and add the results to the database. Based on this information, when any outlet is opened, the system will then be able to provide the most efficient flow into each individual faucet by controlling the associated flow control device 115.

A method of mapping water supply facilities within a building according to a first aspect of the present disclosure will now be described with reference to fig. 6.

The method includes opening a first one of the plurality of controllable water outlets and processing, with the processor 140, a signal from the at least one flow measurement device 110 at least until a first flow characteristic is determined and then closing the first one of the plurality of controllable water outlets. Opening a first one of the plurality of controllable water outlets is preferably indicated by a message sent by the processor or system controller 140 to a mobile device 150 carried by the associated engineer. For example, the instruction may be sent via Wi-Fi and tell the engineer to open the bathtub hot water faucet 136 in the main bathroom 121. The engineer carrying the mobile device 150 then goes to the main bathroom and fully opens the bathtub hot water faucet 136. The mobile device may provide a prompt to the engineer, preferably audible and with a countdown prompt to tell the engineer when to accurately turn on the faucet. Alternatively, an application on the mobile device may be configured to accept input from an engineer, such as a press or release of a button, at the time faucet 136 is opened. In either case, the application may capture the local time for the reminder or moment and then send the local time to the system controller 140 or server 145 along with the identification of the associated controllable outlet. In this way, the delay of the prompt to reach the mobile device 150 or the delay of the time the instruction arrives at the controller 140 or the server 145 may be considered (the mobile device 150 and the system controller 140 preferably undergo some hand-shake process before or after the mapping process so that the damping offset between the clocks of the two devices may be eliminated or the damping offset between the clocks of the two devices may also be considered).

The engineer may then work around the premises, select an identification of the mouth from a list or menu on the application, or enter a clear identifier, opening each of the exits in turn. Or the system controller may already be provided with a list of all water taps etc. (typically "controllable outlets") and may prompt the engineer for a decorrelated outlet by sending another message to the mobile device 150. The application preferably includes an option for the engineer to send a message to the system controller 140/server 145 indicating that she is in place and ready to receive instructions to open the next controllable outlet. The process is then repeated for each of the other hot water outlets until all outlets and their flow characteristics, i.e., hysteresis before flow is detected, flow rise rate, maximum flow rate, and any other identifiable characteristics, are captured and stored in the database. Using the features stored in the database, the processor 140 can then identify the opening of a particular controllable water outlet of the plurality of controllable water outlets based on the similarity of the detected flow features to the corresponding flow features.

Based on the type of outlet (bathroom faucet, kitchen faucet, basin faucet, lavatory faucet) and its location (e.g., main bathroom, suite, child's room, adult's room, lavatory, kitchen), the processor is also provided with some rules regarding preferred flow rate and optionally flow duration, and uses these rules and the outlet identification identified from the detected flow characteristics to determine the target flow rate. The target flow rate is then applied by the system controller 140 by controlling the associated flow controller 115 and is preferably monitored by the corresponding flow measurement device 110. In this way, by controlling at least one flow regulator based on the identification of the associated outlet, the processor 140 is able to control the water supply to the identified controllable water outlet.

Each of the respective flow characteristics may include a respective steady flow rate. The method may then further comprise: the processor 140 is configured to control the at least one flow regulator 115 to apply a flow rate reduction of at least 10% to each of the plurality of controllable water outlets based on the respective steady flow rates. Optionally, the method may further include: the processor 140 is configured to control the at least one flow regulator 115 to apply a flow rate reduction of at least 10% to any one of the plurality of controllable water outlets having a respective steady flow rate greater than 7 liters per minute based on the respective steady flow rate. This applies in particular to faucets serving bathrooms, suites and most particularly wash basins in toilets where faucets are generally used mainly to provide water for hand washing-this can be effectively achieved with fairly moderate flow rates.

The above-described techniques of mapping a hot water supply facility may be used to populate a database or training logic, such as a neural network or Machine Learning Algorithm (MLA), which may be used by a processor associated with an energy library as previously described, so that the processor can better identify a particular outlet or outlet type from the detected flow characteristics and thus more easily estimate the need for hot water from the hot water supply. This in turn may increase the efficiency of controlling the heat pump and using the energy reservoir.

Having described the energy reservoir and its installation and operation in the hot water supply facility, we will now consider how the energy reservoir and the heat pump can be integrated into both the hot water supply system and the space heating means.

Fig. 7 schematically illustrates a possible arrangement of components of the interface unit 10 according to one aspect of the present disclosure. The interface unit is connected between the heat pump (not shown in the figures) and the hot water system inside the building. The interface unit comprises a heat exchanger 12, which heat exchanger 12 comprises an enclosure (not separately numbered) inside which is an input side circuit, shown in a very simplified form as 14, for connection to a heat pump, and an output side circuit, again shown in a very simplified form as 16, for connection to a hot water system (not shown in this figure) inside the building. The heat exchanger 12 also contains a heat storage medium for storing energy, but the heat storage medium is not shown in the drawings. In an example that will now be described with reference to fig. 7, the thermal storage medium is a phase change material. It will be appreciated that the interface unit corresponds to the previously described energy bank. Throughout the specification including the claims, references to energy banks, heat storage media, energy storage media, and phase change materials should be considered interchangeable unless the context clearly requires otherwise.

Typically, the phase change material in the heat exchanger has an energy storage capacity (in terms of the amount of energy stored by means of latent heat of fusion) of between 2 megajoules and 5 megajoules, however more energy storage is possible and may be useful. And of course less energy storage is possible, but it is generally desirable (subject to practical constraints based on physical size, weight, cost and safety) to maximize the potential for energy storage in the phase change material of the interface unit 10. Suitable phase change materials and their properties, as well as dimensions, etc. will be discussed more in the following of the present document.

The input side circuit 14 is connected to a pipe or conduit 18, which pipe or conduit 18 is in turn fed from a node 20 and a pipe 22, the pipe 22 having coupling means 24 for connection to a supply from a heat pump. Node 20 also supplies fluid from the heat pump to conduit 26, conduit 26 terminating in a coupling device 28, which coupling device 28 is intended for connection to a heating network of a house or apartment, for example for connection to an underfloor heating device or a radiator network or both. Thus, once the interface unit 10 is fully installed and operated, fluid heated by the heat pump (which is located outside the house or apartment) passes through the coupling device 24 and along the conduit 22 to the node 20, from which node 20 the fluid flow reaches the input side loop 14 of the heat exchanger along the conduit 18 or out to the heating infrastructure of the house along the conduit 26 and through the coupling device 28, depending on the setting of the 3-way valve 32.

The heated fluid from the heat pump flows through the input side loop 14 of the heat exchanger and out of the heat exchanger 12 along conduit 30. In use, in some cases, the heat carried by the heating fluid from the heat pump releases some of its energy to the phase change material inside the heat exchanger and some to the water in the output side loop 16. In other cases, as will be explained later, the fluid flowing through the input side loop 14 of the heat exchanger actually obtains heat from the phase change material.

Conduit 30 supplies fluid exiting the input side circuit 14 to a motorized 3-way valve 32 and then along conduit 34 to a pump 36 depending on the state of the valve. The pump 36 is used to push the flow onto the external heat pump via the coupling device 38.

The motorized 3-way valve 32 also receives fluid from a conduit 40, the conduit 40 receiving fluid returned from the heating infrastructure (e.g., radiator) of the house or apartment via a coupling 42.

Three transducers are provided between the motorized 3-way valve 32 and the pump 36: a temperature transducer 44, a flow transducer 46, and a pressure transducer 48. In addition, a temperature transducer 49 is provided in the conduit 22, which temperature transducer 49 introduces fluid from the output of the heat pump. These transducers are operatively connected to or accessible by a processor, not shown, like all other transducers in the interface unit 10, which is typically provided as part of the interface unit-but which may be provided in a separate module.

Although not shown in fig. 7, an additional electrical heating element may also be provided in the flow path between the couplers 24, which receives fluid from the output of the heat pump. The additional electric heating element may also be an inductive or resistive heating element and be arranged as a means to compensate for a potential failure of the heat pump, but may also be arranged for adding energy to the heat storage unit (e.g. based on current energy costs and predictions of heating and/or hot water). The additional electric heating element can of course also be controlled by the processor of the system.

The conduit 34 is also coupled with an expansion vessel 50, which expansion vessel 50 is connected with a valve 52, by means of which valve 52 a filling circuit can be connected to replenish the fluid in the heating circuit. As part of the heating circuit of the interface unit, a pressure relief valve 54 is also shown intermediate the node 20 and the input side circuit 14, and a filter 56 (to capture particulate contaminants) is shown intermediate the coupling device 42 and the 3-way valve 32.

The heat exchanger 12 is also provided with several transducers including at least one temperature transducer 58 and a pressure transducer 60, however as shown, preferably more (e.g. up to 4 or more) temperature transducers 58 are provided. In the example shown, the heat exchanger comprises 4 temperature transducers uniformly distributed within the phase change material, so that temperature variations can be determined (and thus knowledge about the state of the phase change material throughout its body is obtained). Such an arrangement may be particularly beneficial during the design/implementation stage as a means to optimize the design of the heat exchanger, including optimizing the additional heat transfer arrangement. Such an arrangement may also continue to be beneficial in a deployed system because having multiple sensors may provide useful information to the processor and the machine learning algorithm employed by the processor (the processor of the interface unit only and/or the processor of the system including the interface unit).

The arrangement of the cold water supply means and the hot water circuit of the interface unit 10 will now be described. Coupling means 62 are provided for connection to a cold water supply from the water mains. Typically, the water will have flowed through the anti-siphon check valve and may have been depressurized before the water from the water mains reaches the interface unit 10. Cold water passes from the coupling 62 along the pipe to the output side circuit 16 of the heat exchanger 12. Whereas we provide a processor that monitors multiple sensors in the interface unit, the same processor may optionally be given another task to perform. I.e. to monitor the pressure at which cold water is delivered from the water supply mains. For this purpose, a further pressure sensor may be introduced into the cold water supply line upstream of the coupling device 62, and in particular upstream of any pressure relief devices within the house. The processor may then monitor the water supply pressure continuously or periodically and even prompt the owner/user to seek compensation from the water supply company if the water mains supplies water at a pressure below the legal minimum.

Water that may have been heated by its passage through the heat exchanger passes from the output side loop 16 along conduit 66 to an electrical heating unit 68. The electrical heating unit 68 under the control of the previously mentioned processor may comprise a resistive or inductive heating device, the heat output of which may be modulated in accordance with instructions from the processor.

The processor is configured to control the electric heater based on the information about the phase change material and the state of the heat pump.

Typically, the electrical heating unit 68 has a rated power of no more than 10kW, however in some cases a more powerful heater, for example a 12kW heater, may be provided.

So far hot water will reach the coupling device 74 along the pipe 70 from the electric heater 68 and a hot water circuit comprising controlled outlets of a house or apartment such as a tap and shower will be connected to the coupling device 74.

A temperature transducer 76 is disposed after the electric heater 68, such as at the outlet of the electric heater 68, to provide information regarding the temperature of the water at the outlet of the hot water system. A pressure relief valve 77 is also provided in the hot water supply device and although this pressure relief valve 77 is shown as being located between the electric heater 68 and the outlet temperature transducer 76, its precise location is not important—as is the case with many of the components illustrated in fig. 7.

There is also a pressure transducer 79 and/or a flow transducer 81 somewhere in the hot water supply line, either of which pressure transducer 79 and flow transducer 81 can be used by the processor to detect the need for hot water-i.e. to detect the opening of a controllable outlet such as a tap or shower. The flow transducer is preferably a transducer without moving parts, e.g. based on acoustic or magnetic flow detection. The processor may then use information from one or both of these transducers and its stored logic to determine whether to signal activation to the heat pump.

It will be appreciated that the processor may invoke the heat pump activation based on demand for space heating (e.g., based on stored programs in the processor or an external controller, and/or based on signals from one or more thermostats-e.g., room statistics, external statistics, underfloor heating statistics) or demand for hot water. The control of the heat pump may be in the form of simple on/off commands, but may also or alternatively be in the form of modulation (using for example ModBus).

As in the case of the heating circuit of the interface unit, three transducers are provided along the cold water supply pipe 64: a temperature transducer 78, a flow transducer 80, and a pressure transducer 82. A further temperature transducer 84 is also provided in the conduit 66 intermediate the outlet of the output side circuit 16 of the heat exchanger 12 and the electric heater 68. These transducers are also all operatively connected to or accessible by the previously mentioned processor.

Also shown on the cold water supply line 64 are a magnetic or electrical water regulator 86, a motorized and modulatable valve 88 (motorized and modulatable valve 88 as well as all motorized valves may be controlled by the previously mentioned processor), a check valve 86 and an expansion vessel 92. The modulatable valve 88 may be controlled to regulate the flow of cold water to maintain a desired temperature of the hot water (as measured, for example, by the temperature transducer 76).

Valves 94 and 96 may also be provided for connection to external storage tanks for storing cold water and heated water, respectively. Finally, a double check valve 98 may be provided to connect the cold water supply line 64 to another valve 100, and the other valve 100 may be used with a fill circuit to connect to the previously mentioned valve 52 for filling the heating circuit with more water or a mixture of water and corrosion inhibitor.

It should be noted that fig. 7 shows various pipe intersections, but unless these intersections are shown as nodes like node 20, the two pipes shown as intersections are not in communication with each other, as should now be apparent from the foregoing description of the drawings.

Although not shown in fig. 7, the heat exchanger 12 may include one or more additional electrical heating elements configured to transfer heat into the thermal storage medium. While this may appear to be counterintuitive, it allows the use of electrical energy to pre-energize the thermal storage medium when economically significant, as will now be explained.

For a long time, energy supply companies have done to charge fees for having the unit electricity costs vary according to different times of day to take into account the time of demand increase or demand decrease and to help shape customer behavior to better balance demand and supply capacity. Historically, rate schemes have been quite coarse, affecting both power generation and electricity consumption technologies. Increasingly, however, the incorporation of renewable energy sources of electricity, such as solar energy (e.g., solar energy from photovoltaic cells, panels, and farms) and wind energy, into power generation structures in countries has motivated the development of more dynamic pricing of energy sources. This approach reflects the inherent variability of this weather-dependent power generation. Initially, such dynamic pricing was largely limited to large-scale users, and more dynamic pricing is being provided to the average customer.

The degree of dynamic pricing varies from country to country and also from manufacturer to manufacturer within a given country. In one extreme case, "dynamic" pricing is simply providing different rates over different time windows of the day, and such rates may be applicable for weeks, months or seasons without variation. Some dynamic pricing regimes enable suppliers to notify the changing prices a day or less ahead-so, for example, customers may today obtain prices for half an hour of the day. Some countries offer time periods as short as 6 minutes and it is conceivable that the lead time for informing customers of upcoming tariffs can be further shortened by including "intelligence" in the energy consuming device.

Since both short-term and mid-term weather predictions can be used to predict both the amount of energy that may be generated by solar and wind energy facilities, as well as the likely scale of power demand for heating and cooling, periods of extreme demand can be predicted. Some power generation companies that have the ability to generate large amounts of renewable energy are known to even provide negative charges for electricity-in effect paying customers for excess power. More commonly, power may be provided at a fraction of the usual rate.

By incorporating an electric heater into an energy storage unit, such as a heat exchanger of a system according to the present disclosure, customers can take advantage of the time period of low cost supply and reduce customer reliance on electricity at high energy prices. This is not only beneficial to individual customers, but is more generally also beneficial because it can reduce demand when excess demand must be met by burning fossil fuels.

The processor of the interface unit has a wired connection or a wireless connection (or both) to a data network, such as the internet, to enable the processor to receive dynamic pricing information from the energy supplier. The processor also preferably has a data link connection (e.g., modBus) with the heat pump to both send instructions to and receive information (e.g., status information and temperature information) from the heat pump. The processor has logic that enables the processor to learn home behavior and, with this home behavior and dynamic pricing information, the processor can determine whether and when to pre-energize the heating system using cheaper power. This may be by using electrical elements inside the heat exchanger to heat the energy storage medium, but alternatively this may be achieved by driving the heat pump to a temperature higher than normal, for example 60 degrees celsius, instead of between 40 and 48 degrees celsius. When the heat pump is operated at a higher temperature, the efficiency of the heat pump is reduced, but the processor may take this into account when deciding when and how to best use cheaper electricity.

The local system processor may benefit from external computing capabilities because the system processor can be connected to a data network, such as the internet and/or a provider's intranet. Thus, for example, a manufacturer of an interface unit may have a cloud rendering technology (or intranet) in which computing power is provided for, for example, predictive computation of: occupancy rate; activity degree; rate (short/long); weather forecast (which may be more preferable than generally available because they can be pre-processed for easy use by the local processor and can also be tailored very specifically to the situation, location, exposure of the property in which the interface unit is installed); identification of false positives and/or false negatives.

In order to protect the user from the risk of scalding from superheated water from the hot water supply system, it is advisable to provide a scalding protection feature. This may take the form: an electrically controllable (modulatable) valve is provided to mix cold water from the cold water supply into the hot water as the hot water exits the output circuit of the heat exchanger.

Fig. 7 schematically shows what might be considered "main parts" of the interface unit, but does not show any containers for these "main parts". An important application of the interface unit according to the present disclosure is as a means: the arrangement enables the heat pump to be used as a practical contributor to space heating and hot water requirements of a residence where a gas boiler was previously provided (or might otherwise be fitted with such a boiler), it being understood that it is generally convenient to provide a container that is both aesthetically pleasing and safe, as is the case with conventional hybrid boilers. Furthermore, preferably, any such vessel will be sized to fit a form factor that enables direct replacement of the hybrid boiler-the hybrid boiler is typically wall mounted, typically in a kitchen, where the hybrid boiler coexists with a cabinet. Based on the form of a generally rectangular cube having a height, width and depth (of course, curved surfaces may be used for any or all of the surfaces of the container for aesthetic, ergonomic or safety reasons), suitable dimensions may be found within the following approximate ranges: the height is 650mm to 800mm; width 350mm to 550mm; the depth is 260mm to 420mm; for example 800mm high, 500mm wide, 400mm deep, however larger, in particular higher units may be provided for mounting where these units may be accommodated.

One significant difference of the interface unit according to the present disclosure with respect to the gas mixing boiler is that, although the vessel of the gas mixing boiler typically has to be made of a non-combustible material such as steel, the internal temperature of the interface unit will typically be significantly below 100 degrees celsius, typically below 70 degrees celsius, and often below 60 degrees celsius due to the presence of the hot combustion chamber. Thus, it becomes feasible to use flammable materials such as wood, bamboo or even paper when manufacturing the container for the interface unit.

The lack of combustion also provides the possibility of mounting the interface unit in a location that is generally considered unsuitable for mounting a gas mixing boiler-of course, unlike a gas mixing boiler, the interface unit according to the present disclosure does not require an exhaust flue. Thus, for example, the interface unit may be configured to fit under a kitchen counter top, and may even utilize well known dead corners represented by under-counter corners. For installation in such a position, the interface unit may in fact be integrated into the under-counter closet-preferably by co-operation with the closet manufacturer. But by having the interface unit effectively behind some form of kitchen cabinet configured to allow access to the interface unit, maximum flexibility of deployment may be maintained. The interface unit will then preferably be configured to allow the circulation pump 36 to slide out and away from the heat exchanger 12 before the circulation pump 36 is disengaged from the flow path of the input side loop.

It is also contemplated to utilize other space that is often wasted in an installed kitchen, i.e., under the under-counter closet. There is typically room (however, room for any leg supporting the cabinet) for heights exceeding 150mm, depths of about 600mm, widths of 300mm, 400mm, 500mm, 600mm or more. In particular for new installations or for replacement of hybrid boilers in kitchen retrofitting, it is expedient to use these spaces at least for the heat exchangers of the interface unit-or for a given interface unit to use more than one heat exchanger unit.

Particularly for interface units designed for wall mounting, it is often desirable to design the interface unit as a plurality of modules, although there are potential benefits whatever the application of the interface unit. With such a design, the heat exchanger can be conveniently used as one of the modules, since the presence of the phase change material can result in a weight of the heat exchanger itself exceeding 25kg. For health and safety reasons and to facilitate single person installation, it is desirable to ensure that the interface unit can be delivered as a set of modules, none of which weigh more than about 25kg.

Such weight limitation may be supported by making one of the modules a chassis for mounting the interface unit to the structure. For example, in case the interface unit is to be mounted on a wall instead of an existing gas mixing boiler, it may be convenient that the chassis supporting the other modules may first be fixed to the wall. Preferably, the chassis is designed to work with the position of the existing fixing points for supporting the hybrid boiler being replaced. This may be achieved by providing a "universal" chassis with preformed fixing holes according to the spacing and location of popular gas mixing boilers. Alternatively, it may be cost effective to produce a series of chassis: the series of trays each have hole locations/sizes/spacings that match the hole locations/sizes/spacings of the boilers of the particular manufacturer. Only then only the appropriate chassis has to be specified for replacement of the boilers of the relevant manufacturer. This approach has several benefits: it avoids the need to drill more holes for the plug to employ the fixing bolts-and this not only eliminates the time required for marking, drilling and cleaning, but also avoids the need to further weaken the residential structure being installed-which can be an important consideration given to the low cost construction techniques and materials often used in "take off houses" and other low cost houses.

Preferably, the heat exchanger module and the chassis module are configured to be coupled together. In this way, the need for separable fasteners can be avoided, again saving installation time.

Preferably, the additional module includes first interconnections, such as 62 and 74, to couple the output side circuit 16 of the heat exchanger 12 to the in-building hot water system. Preferably, the additional module further includes a second interconnect, such as 38 and 24, to couple the input side circuit 14 of the heat exchanger 12 to the heat pump. Preferably, the add-on module further comprises third interconnections, e.g. 42 and 28, to couple the interface unit to the thermal circuit of the house in which the interface unit is used. It will be appreciated that by mounting the heat exchanger to the chassis itself directly attached to the wall, rather than first mounting the connector to the chassis, the weight of the heat exchanger is kept closer to the wall, thereby reducing the cantilever loading effect on the wall mount which secures the interface unit to the wall.

Phase change material

One suitable class of phase change materials is paraffin waxes, which have a solid-liquid phase change at the temperatures that are advantageous for domestic hot water supply and use in conjunction with heat pumps. Particularly advantageous are paraffin waxes which melt at temperatures in the range of 40 degrees celsius to 60 degrees celsius, and in this range it can be found that the waxes melt at different temperatures to suit a particular application. Typical latent heat capacities are between about 180kJ/kg and 230kJ/kg, with a specific heat of about 2.27Jg in the liquid phase ^-1 K ^-1 About 2.1Jg in solid phase ^-1 K ^-1 . It can be seen that considerable energy can be stored using latent heat of fusion. By heating the phase change liquid above its melting point, more energy can also be stored. For example, when the cost of electricity is relatively low and it can be predicted that hot water will be needed soon (when electricity may or is known to be more expensive), it makes sense to run the heat pump at a temperature above normal to "superheat" the thermal energy store.

A suitable choice of wax may be a wax having a melting point of about 48 degrees Celsius, such as n-tricosane C ₂₃ Or paraffin C ₂₀ To C ₃₃ . Will beA standard 3K temperature difference is applied to the whole heat exchanger (between the liquid supplied by the heat pump and the phase change material in the heat exchanger) resulting in a heat pump liquid temperature of about 51 degrees celsius. And similarly, on the output side, allowing a 3K temperature drop, we get a water temperature of 45 degrees celsius, which is satisfactory for general domestic hot water-hot enough for kitchen faucets but possibly somewhat high for shower/bath faucets-but obviously cold water can always be added to the water flow to reduce the water temperature. Of course, phase change materials with lower melting points may be considered if the household is trained to accept lower hot water temperatures, or if they are acceptable for some other reason, but phase change temperatures typically in the range of 45 to 50 may be a good choice. Clearly we consider the risk of legionella by storing water at such temperatures.

Heat pumps (e.g., ground or air source heat pumps) have an operating temperature of up to 60 degrees celsius (however, operating temperatures of up to 72 degrees celsius are possible by using propane as the refrigerant), but when operated at temperatures in the range of 45 degrees celsius to 50 degrees celsius, their efficiency tends to be much higher. So our 51 degrees celsius starting from a phase transition temperature of 48 degrees celsius may be satisfactory.

The temperature performance of the heat pump also needs to be considered. In general, the maximum Δt (the difference between the input temperature and the output temperature of the fluid heated by the heat pump) is preferably maintained in the range of 5 degrees celsius to 7 degrees celsius, however Δt may be as high as 10 degrees celsius.

While paraffin waxes are the preferred materials for use as energy storage media, they are not the only suitable materials. Salt hydrates are also suitable for use in latent heat energy storage systems, such as current systems. In this case, the salt hydrate is a mixture of inorganic salt and water, wherein the phase change involves loss of all or most of the water in which it is water. Upon phase transition, the hydrate crystals are separated into anhydrous (or less water-containing) salts and water. The advantage of salt hydrates is that they have a much higher thermal conductivity (2 to 5 times higher) than paraffin and a much smaller volume change upon phase change. Suitable salt hydrates for the present application are Na ₂ S ₂ O ₃ .5H ₂ O, which has a melting point of about 48 degrees Celsius to 49 degrees Celsius and a latent heat of 200/220kJ/kg.

Phase change materials having a phase change temperature significantly higher than the range of 40 degrees celsius to 50 degrees celsius are also contemplated for use with respect to energy storage alone. For example, paraffin waxes, waxes that can be used have a wide range of melting points:

n-heneicosane C with a melting point of about 40 DEG C ₂₄ ；

N-behenic acid with a melting point of about 44.5 degrees celsius ₂₁ ；

N-tetracosane C with melting point of about 52 DEG C ₂₃ ；

N-cyclopentadecane C having a melting point of about 54 degrees Celsius ₂₅ ；

N-hexacosane C with a melting point of about 56.5 degrees Celsius ₂₆ ；

N-heptadecane C having a melting point of about 59 DEG C ₂₇ ；

N-octacosane C having a melting point of about 64.5 degrees Celsius ₂₈ ；

N-icosanonadecane C having a melting point of about 65 degrees Celsius ₂₉ ；

N-ditridecane C having a melting point of about 66 degrees celsius ₃₀ ；

n-Triundecane C with melting point of about 67 DEG C ₃₁ ；

N-tridecane C having a melting point of about 69 degrees Celsius ₃₂ ；

N-tridecane C having a melting point of about 71 degrees Celsius ₃₃ ；

Paraffin C having a melting point of about 58 degrees Celsius to 60 degrees Celsius ₂₂ To C ₄₅ ；

Paraffin C having a melting point of about 66 degrees celsius to 68 degrees celsius ₂₁ To C ₅₀ ；

RT 70HC having a melting point of about 69 degrees celsius to 71 degrees celsius.

Alternatively, salt hydrates, such as CH, may be used ₃ COONa.3H ₂ O, which has a melting point of about 58 degrees Celsius and a latent heat of 226/265kJ/kg.

So far, thermal energy storage has been described primarily as having a single mass of phase change material within a heat exchanger having an input circuit and an output circuit, each in the form of one or more coils or loops. It is also advantageous in terms of heat transfer rate, however, for example, that the phase change material is encapsulated in a plurality of sealing bodies, for example in a metal (e.g. copper or copper alloy) cartridge (or other elongated form), which are surrounded by a heat transfer liquid from which an output circuit, which is preferably used for providing hot water for a (domestic) hot water system, extracts heat.

With this configuration, the heat transfer liquid may be sealed in a heat exchanger, or more preferably, the heat transfer liquid may flow through the energy storage and may be a heat transfer liquid that transfers heat from a green energy source (e.g., a heat pump) without using an input heat transfer coil in the energy storage. In this way, the input circuit may simply be provided by one (or more typically multiple) inlet(s) and one or more outlet(s) such that the heat transfer liquid passes freely through the heat exchanger, without being limited by coils or other conventional conduits, the heat transfer liquid transfers heat to or from the packaged PCM, and then onto the output circuit (and thus the water in the output circuit). In this way, the input circuit is defined by one or more inlets and one or more outlets for the heat transfer liquid and a free-form path through the packaged PCM and through the energy storage.

Preferably, the PCM is packaged in a plurality of elongated closed-ended tubes arranged in one or more spaced apart ways (e.g., staggered rows of tubes, each row including a plurality of spaced apart tubes), wherein the heat transfer fluid is preferably arranged to flow over the tubes, either laterally (or transverse to the length of the tubes or other packaging enclosure) on the way from the inlet to the outlet, or, in the case of an input coil, by one or more impellers disposed within the thermal energy storage.

Alternatively, the output circuit may be arranged at the top of the energy storage and positioned above and over the encapsulated pcm—the vessel of the encapsulated PCM may be disposed horizontally and above the input circuit or coil (such that convection supports energy transfer up through the energy storage), or the inlet of the incoming heat transfer liquid is directed against the encapsulated PCM and optionally towards the upper output circuit. If one or more impellers are used, the or each impeller is preferably magnetically coupled to an externally mounted motor-so as not to compromise the integrity of the enclosure of the energy store.

Alternatively, the PCM may be packaged in an elongate tube, typically having a circular cross section with a nominal outer diameter in the range 20mm to 67mm, for example 22mm, 28mm, 35mm, 42mm, 54mm or 67mm, and typically these tubes will be formed of copper suitable for plumbing use. Preferably, the outer diameter of the pipe is between 22mm and 54mm, for example between 28mm and 42 mm.

The heat transfer liquid is preferably water or a water-based liquid, such as water mixed with one or more flow additives, corrosion inhibitors, antifreeze, biocides, and may for example comprise inhibitors of the type designed for use in a central heating system, such as Sentinel X100 or fernox f1 (both RTMs), suitably diluted in water.

Thus, throughout the specification and claims of the present application, unless the context clearly requires otherwise, the term "input circuit" should be interpreted to include the arrangement just described, and wherein the liquid flow path from the input end of the input circuit to its output end is not defined by a conventional conduit, but rather involves substantially free flowing liquid within the enclosure of the energy storage.

The PCM may be packaged in a plurality of elongated cartridges having a circular or substantially circular cross-section, the cartridges preferably being arranged in one or more rows at intervals. Preferably, the cylinders in adjacent rows are offset relative to one another to facilitate heat transfer from and to the heat transfer liquid. Optionally, the following input means are provided: wherein the heat transfer liquid is introduced into the space around the package through one or more input ports, which may be in the form of a plurality of input nozzles, which direct and direct the input heat transfer liquid onto the package supplied by the input manifold. The orifice of the nozzle at its outlet may be generally circular in cross-section or may be elongated to create a liquid jet or liquid flow that more efficiently transfers heat to the encapsulated PCM. The manifold may be fed from a single end or from the opposite end in view of increasing flow rate and reducing pressure loss.

Due to the pumping of the green energy source (e.g. a heat pump or a solar water heating system) or another system pump, the heat transfer liquid may be pumped into the energy storage 12, or the thermal energy storage may comprise its own pump. The heat transfer liquid may be returned directly to the energy source (e.g., a heat pump) after exiting the energy storage at one or more outlets of the input circuit, or may be switched by using one or more valves to first pass through a heating device (e.g., an underfloor heating system, a radiator, or some other form of space heating system) before returning to the green energy source.

The package may be positioned horizontally such that the coil of the output loop is above and over the package. It should be understood that this is but one of many possible arrangements and orientations. The same arrangement may also be positioned such that the packages are arranged vertically.

Alternatively, an energy store packaged using PCM may again use a cylindrical elongate package, such as those previously described, but in this case has an input circuit in the form of a conduit, for example in the form of a coil. The enclosure may be arranged such that its long axis is disposed vertically and the input coil 14 and output coil 18 are disposed on either side of the energy storage 12. But again this arrangement may be used in alternative orientations, such as with the input loop at the bottom and the output loop at the top, and the long axis of the package disposed horizontally. Preferably, one or more impellers are disposed within energy storage 12 to push energy transfer liquid from around input coil 14 toward the enclosure. The or each impeller is preferably coupled to an externally mounted drive unit (e.g. an electric motor) via a magnetic drive system so that the enclosure of the energy store 12 does not need perforations to receive the drive shafts, thereby reducing the risk of leakage of these shafts into the enclosure.

Due to the fact that the PCM is encapsulated, it becomes easy to construct an energy storage using more than one phase change material for energy storage, and in particular allows to create an energy storage unit in which PCMs with different transition (e.g. melting) temperatures can be combined, thereby expanding the operating temperature of the energy storage.

It should be appreciated that in embodiments of the type just described, the energy storage 12 comprises one or more phase change materials to store energy as latent heat in conjunction with a heat transfer liquid (e.g., water or water/inhibitor solution).

A plurality of elastomers are preferably disposed within the package along with the phase change material (which may also be used for energy reservoirs using "bulk" PCM, as described elsewhere in this specification), the plurality of elastomers being configured to decrease in volume in response to an increase in pressure caused by a phase change of the phase change material and to re-expand in response to a decrease in pressure caused by an opposite phase change of the phase change material.

As previously described, referring to fig. 1, the state of the phase change material may be determined based on its internal pressure. The pressure transducer may be coupled to the processor of the interface unit. Thus, the processor of the interface unit receives a signal related to the degree of solidification/liquefaction of the phase change material, which provides information about the energy storage of the phase change material. Based on empirical analysis of the prototypes, the processor of the interface unit may be programmed during or after manufacture so that the degree of solidification (more generally, the state) of the phase change material may be mapped to a pressure signal from the pressure transducer. For example, a pre-production prototype may be fitted with glass side plates so that the state of the phase change material can be determined by inspection/analysis and mapped to a pressure signal from a pressure transducer, knowledge of the latent heat of fusion of the phase change material used will enable the amount of latent heat stored in the heat exchanger to be calculated for each pressure measured. The data obtained in this way can then be used when programming the processor for producing the interface unit and when teaching the machine learning algorithm in this and potentially other processors in the system.

Also as previously mentioned, another method of monitoring the state of the phase change material that may be provided as an alternative to or in addition to one or more of the foregoing methods is to provide one or more light sources to emit light radiation into the body of phase change material for detection by one or more appropriately positioned optical sensors (optical sensing devices). One or more light sources may operate at a single wavelength or range of wavelengths (i.e., in effect a single color), or may operate at two or more spaced apart wavelengths (i.e., different colors). The radiation may be in the visible or infrared region of the spectrum, or in both the visible or infrared region where multiple colors of light are used. The light source may be an incoherent light source such as an LED, or may be a laser such as an LED laser. The light source may be a single red, green and blue light emitting diode. The optical sensing device may be coupled to a processor (e.g., a processor of the interface unit) configured to estimate an amount of energy stored in the phase change material based on information received from the optical sensing device.

Also as previously mentioned, another method of monitoring the state of the phase change material that may be provided as an alternative to or in addition to one or more of the foregoing methods is to provide a sound source configured to emit sound into the phase change material within the heat exchanger and a sound sensing device to detect the sound emitted from the sound source after the sound has passed through the phase change material. Preferably, the sound source is configured to generate ultrasonic waves.

Claims

1. A hot water supply system comprising:

a controllable hot water supply outlet having a given flow rate when fully open;

a thermal energy store comprising an energy storage medium comprising a phase change material to store energy as latent heat, the thermal energy store configured to receive energy from a source of renewable energy;

renewable energy sources;

the hot water supply system is operable to heat water to be supplied to the hot water outlet to a target system supply temperature under control of a processor using a selection of one or more of the renewable energy source, energy from the thermal energy store and optionally an auxiliary water heater located intermediate the thermal energy store and the hot water supply outlet;

wherein the thermal energy store has an energy storage capacity, which when fully energized is sufficient to provide hot water to the hot water outlet at the given flow rate 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 further configured to provide building heating under control of the processor,

The processor is configured to:

monitoring the actual demand of hot water from the hot water supply system;

predicting a future demand for hot water from the hot water supply system based on the monitored actual demand;

pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand; and temporarily transferring heat from the renewable energy source to energize the phase change material instead of providing building heating.

2. The hot water supply system according to claim 1, wherein the source of renewable energy is a solar water heating device or a heat pump.

3. A hot water supply system according to claim 1 or claim 2, wherein the renewable energy source is a solar water heating device or a heat pump.

4. A hot water supply system according to claim 3 when dependent on claim 2, wherein the source of renewable energy from which the thermal energy store is configured to receive energy is the renewable energy source.

5. A hot water supply system according to any one of the preceding claims, wherein the energy store comprises an electrical heating element to enable energisation of the phase change material using heat from the electrical heating element.

6. A hot water supply system according to any one of the preceding claims, wherein the processor is configured to decide when and how much to energize the PCM based on predicted future demand and taking into account the cost of energy to be used.

7. A hot water supply system according to any one of the preceding claims wherein the thermal energy store comprises sufficient phase change material to store between 5 and 10 millijoules of latent heat.

8. The hot water supply system according to any one of the preceding claims, wherein the processor is configured to use data from one or more occupancy sensors to predict future demands of hot water from the hot water supply system.

9. The hot water supply system according to any one of the preceding claims, wherein the processor is configured to use forecasted weather information to predict future demands of hot water from the hot water supply system.

10. A hot water supply system according to any one of the preceding claims, wherein the processor is configured to use data from one or more ambient temperature sensors to predict future demands of hot water from the hot water supply system.

11. The hot water supply system according to any one of the preceding claims, wherein the hot water supply system serves a single household and the processor is configured to use calendar and schedule information of members of the household to predict future demands of hot water from the hot water supply system.

12. A method of controlling a heating appliance in a hot water supply system having a controllable hot water supply outlet with a given flow rate when fully open, and comprising:

renewable energy sources;

Wherein the thermal energy store has an energy storage capacity, which when fully energized is sufficient to provide hot water to the hot water outlet at the given flow rate and at the target system supply temperature for a period of at least 8 minutes, and preferably at least 10 minutes; and wherein the renewable energy source is further configured to provide building heating under control of the processor, the method comprising:

monitoring the actual demand of hot water from the hot water supply system;

monitoring future demand for hot water from the hot water supply system based on the monitored actual demand; and

pre-energizing the thermal energy store such that sufficient energy will be stored in the thermal energy store to meet the predicted demand; and is also provided with

The processor temporarily transfers heat from the renewable energy source to energize the phase change material instead of providing building heating.

13. The method of claim 12, further comprising using an electrical heating element within the energy storage to energize the phase change material with heat from the electrical heating element.

14. The method of claim 12 or claim 13, further comprising deciding when and how much to energize the PCM based on the predicted future demand and taking into account the cost of energy to be used.

15. The method of any one of the preceding claims, further comprising using data from one or more occupancy sensors to predict future demand for hot water from the hot water supply system.

16. The method of any one of the preceding claims, further comprising using forecasted weather information to predict future demand for hot water from the hot water supply system.

17. The method of any one of the preceding claims, further comprising using data from one or more ambient temperature sensors to predict future demand for hot water from the hot water supply system.

18. The method of any one of the preceding claims, wherein the hot water supply system serves a single household, the method further comprising using calendar and schedule information of members of the household to predict future demands of hot water from the hot water supply system.

19. The method of any of the preceding claims, wherein the thermal energy store comprises sufficient phase change material to store between 5 and 10 millijoules of latent heat.