WO2015158782A1

WO2015158782A1 - Water-heater system with alterable energy consumption

Info

Publication number: WO2015158782A1
Application number: PCT/EP2015/058182
Authority: WO
Inventors: Anne-Sophie Coince
Original assignee: Electricite De France
Priority date: 2014-04-15
Filing date: 2015-04-15
Publication date: 2015-10-22
Also published as: FR3019882A1

Abstract

The invention relates to a method for modifying the energy consumption of a water tank (10), the method being characterized in that it comprises steps of: (a) reception of data descriptive of a state of an electrical network (2), comprising instantaneous data and forecast data quantifying a surplus or a deficit of renewable original energy within the network (2); (b) calculation by a management element (30) of a threshold of power injectable onto the network (2) as a function of a potential energy capacity of the water tank (10) and of said forecast data; (c) generation by the management element (30) of a dynamic power setting as a function of said threshold of injectable power and of said instantaneous data; (d) sending of said setting to a control module (12) for a heating device (11) for heating the water of the tank (10), the heating device (11) comprising a heating means powered by the electrical network (2); (e) power regulation of said heating means by the control module (12) as a function of the power setting.

Description

Modular energy-efficient water heater system

GENERAL TECHNICAL FIELD The present invention relates to a method for modulating the energy consumption of a water heater.

STATE OF THE ART The "energy mix" designates the distribution of the various sources consumed for the production of electrical energy. This energy mix, in constant evolution, sees the constant progression of the Renewable Energies, which entails an increased need in flexibilities of the system.

The latter, mainly represented by wind power and photovoltaics, do not allow a constant and regulated production, unlike a nuclear power plant, hence the problems of variability and predictability of the associated production. This makes the risks of the very short term increase sharply.

On the other hand, local problems of quality of electrical supply will be amplified because of inhomogeneous geographical distribution of the installations, with for example rather photovoltaic in the South and wind power in the North.

It seems essential to find solutions for controlling the associated load in order to control the risk associated with Renewable Energies.

For example, it has been proposed to charge stationary batteries to facilitate the massive insertion of photovoltaic panels ("NiceGrid" demonstrator). However, the high investment costs do not allow to consider a large scale deployment of this alternative solution. It is also planned to act on the reactive power provided by the photovoltaic panels to adjust the voltage. However, this last track does not answer to the stakes of control of the wind hazard.

Alternatively to storage via batteries, it is possible to store the energy thermally. With nearly 12 million units installed in France, more than 80% of which are slaved to the Peak Hours / Off-Peak (HP / HC) tariff signal, the Joule water heater (CEJ) residential storage pool - used today for the daily smoothing of the load curve - is likely to meet these new challenges.

The Applicant has thus proposed mechanisms making it possible to easily and efficiently use the storage capacity of joule or thermodynamic water heaters for regulating renewable electrical energy (see, for example, Applications FR1363229, FR1452015 or FR1452022).

We note that these mechanisms provide satisfaction and significantly reduce the "renewable" power injected into the network, while limiting non-renewable energy consumption. The idea is to extract as much renewable energy as possible from the grid, in order to get ahead and not to consume energy from non-renewable sources or to lose energy. energy of renewable origin by capping.

However, it can be seen that the amount of renewable energy available is sometimes higher than the needs, especially the high production days (sunny summer days), which makes the electricity network subject to "peak" phenomena. of renewable energy, hence the need to strengthen the network infrastructure to avoid overloads and incidents.

By way of example, FIG. 2a represents the instantaneous electrical powers that could be encountered along such a sunny day at the meter of a standard-sized dwelling having its own photovoltaic panels. Note the high power of renewable energy reached around noon, and the "curve of deviations" (CDE) associated. The difference curve represents the difference between the energy produced by the dwelling and the energy consumed. We see that over a large part of the day the balance sheet is surplus (CDE positive) and energy is injected into the electricity grid. On the contrary, at night, the budget is negative (CDE negative) and the house consumes electricity, especially in the evening and early morning (off-peak hours) to warm up the water of the EYC.

It was proposed a "meridian recovery" of the EJC regulated in all or nothing, that is to say, a rise in water temperature of the water heater around noon. This makes it possible to consume a portion of the renewable energy surplus and to limit night energy consumption (energy of non-renewable origin). But as can be seen in FIG. 2b, this does not make it possible to avoid the maximum peak of energy injection of renewable origin in the electrical network, and in addition adds significant power variations which are bad for network infrastructure especially since there is no proliferation of local production.

The implementation of self-consumption maximization techniques of renewable energy (as described in the aforementioned applications and mentioned above), ie the modulation of the consumption of the water heater so as to prevent the injection on the network of energy from renewable sources, is effective (almost more night consumption of energy of non-renewable origin), but as we see in Figure 2c this may be insufficient and not allow to absorb the peak of injection that takes place in the late afternoon if the day is sunny.

Thus, although we reduce the global amount of renewable energy injected on the day, the power grid is still solicited.

A simple solution to which the skilled person can think is to delay the start of the EYC in the previous situation (for example by prohibiting the restart before 1 1 h), but as seen in Figure 2d, this only allows to limit the injection peaks marginally. Even worse, the variations in power injected are still more brutal than before, and the comfort of the user can be degraded in case of unexpected demand for hot water in the morning.

It would thus be desirable to have an improved strategy for managing the energy consumption of water heaters making it possible to limit as much as possible the peaks and variations in renewable energy power injected into the network, irrespective of the climatic conditions (in other words whatever the profile of renewable energy production on the day), while limiting the costs and without deteriorating the comfort of the user.

PRESENTATION OF THE INVENTION

The invention proposes to overcome these disadvantages by proposing according to a first aspect a method for modifying the energy consumption of a water tank, the method being characterized in that it comprises steps of:

(a) receiving data describing a state of an electrical network, including instantaneous data and forecast data quantifying a renewable energy surplus or deficit within the network;

(b) calculation by a management element of an injectable power threshold on the network as a function of a potential energy capacity of a water reservoir and said forecast data;

(c) generating by the management element a dynamic power setpoint as a function of said injectable power threshold and said instantaneous data;

(d) sending said setpoint to a control module of a tank water heating device, the heating device comprising a heating means powered by the electrical network; (e) power regulation of said heating means by the control module as a function of the power setpoint.

The device according to the invention is advantageously completed by the following features, taken alone or in any of their technically possible combination:

Which step (b) comprises the estimation by the management element of said potential energy capacity of the water reservoir as a function of a signal representative of the temperature of the reservoir water generated by a temperature probe ;

Said signal representative of the water temperature of the reservoir is intercepted and modified by a decoy element disposed between the probe and the control module according to said data describing a state of the electrical network to be representative of a temperature lower than the actual water temperature of the tank, so as to increase the potential energy capacity of the tank;

• the forecast data quantifying a renewable energy surplus or deficit within the network are daily data, with steps (a) and (b) being implemented at least once a day;

The power threshold for injectable power on the network is such that the integral of the surplus energy at a power greater than said threshold is less than or equal to said potential energy capacity of the water reservoir;

Step (b) comprises comparing said injectable power threshold on the network with a maximum threshold provided with the data describing a state of an electrical network;

Step (b) comprises starting an auxiliary energy storage device if said power threshold for injection on the network is greater than said maximum threshold;

Step (b) comprises, if said threshold of injectable power on the network is below said maximum threshold, the replacement of the power threshold injectable on the network by a higher value between the power threshold injectable on the network as calculated and the maximum threshold;

• said replacement of the network power injectable threshold is only implemented if a renewable electricity purchase price is higher than a minimum electricity sale price;

Step (b) comprises, if said power threshold for injection on the network is greater than said maximum threshold, the increase by a decoy element of the potential energy capacity of the reservoir until the power threshold for injection on the network obtained is equal to the maximum threshold;

Step (a) comprising receiving said data describing a state of the electrical network by a box from a communication network, the box being connected to said management element or to the control module;

The network comprises a local network comprising local means for producing renewable energy connected downstream of a meter, the projected instantaneous data quantifying a surplus or a deficit of renewable energy within the network being consumption data. provided by the meter;

• the control module is configured to ignore the power setpoint when a tank water temperature is higher than a predefined threshold.

According to a second aspect, the invention relates to a system comprising:

- a water tank;

a device for heating the water of the tank, the device comprising a heating means powered by an electrical network;

a temperature probe configured to emit a signal representative of the water temperature of the tank;

a control module regulating in power the heating means of said heating device; the system being characterized in that it further comprises a management element configured for implementing the method according to one of the preceding claims.

PRESENTATION OF FIGURES

Other features, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and which should be read with reference to the appended drawings in which:

FIG. 1a is a diagram of a first embodiment of a system for implementing the method according to the invention;

FIG. 1b is a diagram of a second embodiment of a system for implementing the method according to the invention;

FIGS. 2a-2d previously described represent examples of load curves, production curves and day-day differences obtained during the implementation of known methods;

FIGS. 3a-3c show examples of load curves, production curves and summer day differences obtained during the implementation of the method according to the invention.

DETAILED DESCRIPTION

General Architecture

FIG. 1a represents the general architecture of a preferred embodiment of the system 1 for implementing the method for modifying the energy consumption of a water tank, according to the invention. This system is typically a domestic Joule water heater (CEJ), although the invention is not limited to these (44% of the habitats are equipped with it).

The system 1 thus comprises: - The water tank 10 on the energy capacity of which we will play (commonly called "balloon" hot water);

- A heater 1 1 of the water tank 10, the device 1 1 comprising a heating means powered by an electrical network 2;

a temperature sensor 20 configured to emit a signal representative of the temperature of the water of the tank 10;

a control module 12 of said heating device 1 1 as a function of said signal emitted by the probe 20.

The electric heating means of the heating device 1 1 is generally a resistance, hence the heating of the water Joule effect. Alternatively, it may be for example a complete heat pump whose hot source is in heat exchange with the water of the tank 10 (and the cold source in heat exchange for example with the outside air), so to allow heating of the water with an efficiency higher than 100%, possibly with a supplementary resistance.

Preferably, the device 1 1 is entirely electric (it thus includes only heating means powered by the network 2, and no gas burners for example). The heating energy supplied to the water is then entirely of electrical origin. The system is however not limited to this configuration and the device 1 1 may alternatively further comprise an alternative heating means (non-electric) such as a burner, an exchanger with a solar collector, etc.

The network 2 is a large-scale network that connects a plurality of electrical sources. As explained above, it is at the same time of energy of non-renewable origin (nuclear and / or fossil) and of renewable origin (solar, wind, etc.). Renewable energy presents problems of variability and predictability, while non-renewable energy is more readily available.

Assuming that the user of the system 1 comprises a personal source of renewable energy (eg panels roof photovoltaic generators), as in the particular case shown in FIG. 1 b, it is understood that the network 2 encompasses both the global electricity network 2a and the local electrical network of the user 2b (in other words that the remote central and local solar panels can both feed the heater 1 1). An energy source is defined in the local network 2b if it is connected downstream of the electric meter 31. Conversely, a power source is defined in the global network 2a if it is connected upstream of the electric meter 31. We will for the moment consider the electrical network 2 as a whole, but for some embodiments described below we will take into account the local network 2b.

System 1 is temperature regulated. For this it comprises one or more temperature probes 20 (which will be described in more detail below) and a control module 12 of the heating device 11. The probe or probes 20 continuously or intermittently send a signal representative of the temperature of the water of the reservoir 10. This signal may be a sending of data representing the temperature numerically, or as will be seen below an electrical signal having a parameter is a function of the temperature.

The control module 12 is typically an electronic card that triggers or not the heating according to the temperature of the water and many other possible parameters (programming, season, time periods, off-peak hours / full hours, usual uses of the user, etc.).

In general, a Joule water heater usually includes two threshold temperatures (the value of which may vary depending on the moment and personal settings): a first threshold temperature which is the "minimum" temperature and a second threshold temperature which is the "maximum" temperature (the first threshold is lower than the second threshold). These two thresholds are a few degrees around (for example +/- 4 ° C) a temperature of "comfort" which is the desired average temperature set by the user (the interval 50-65 ° C is current). The control module 12 is thus configured to activate the heater 1 1 when the received signal is representative of a temperature below the first predefined threshold, and / or configured to disable the heater 1 1 when the received signal is representative a temperature higher than the second predefined threshold.

Thus, as the heater 1 1 is stopped and that is between the two thresholds nothing happens. If the temperature drops (over time or because the user draws hot water) and goes below the first threshold, the heater 1 1 is activated, until the second threshold (temperature is reached). maximum, greater than the first threshold). The temperature then goes down again, and so on. In other words, there is an alternation of "cooling" phases during which the temperature drops from the second threshold to the first threshold (see above if the user continues to use hot water), and "Heating" phases during which the temperature rises under the effect of the device 1 1 lit from a temperature less than or equal to the first threshold to the second threshold.

As explained before, this configuration may depend on other parameters, and there may be more than two thresholds, possibly mobile, for example in order to optimize energy consumption during off-peak hours (water heaters are often provided for to raise the temperature of the water preferentially in the early morning, so as to maximize the use of the off-peak hours and to have hot water in quantity at the moment of showering).

In practice, the first and second thresholds are often the consequence of a hysteresis phenomenon around a median value, which defines these two thresholds. The induced difference is then about 3 ° C.

The present invention is not limited to any particular configuration, it will be understood that, in general, the control module 12 regulates the temperature of the tank 10 via the activation / deactivation of the heater 1 1 according to signals that it are emitted, signals which can represent temperatures and / or operating instructions.

Power regulation

The present heater 1 1 is a power control device, that is to say it adapts the power of the heating means by Joule effect according to different needs.

The control module 12 thus regulates the heating means by the Joule effect of the heating device 11.

For this, those skilled in the art may for example use power actuators as described in either of the applications FR1452015 and FR1452022. These power actuators are components for modifying the power of the heating means with which they are associated. In particular, a power actuator modifies the intensity and / or the voltage (in particular only the voltage) of the current on a branch so as to measure the effective power consumed by the associated heating means between 0 and 100% of its value. nominal (ie its maximum power). In other words, to each heating means of nominal power P _£ is associated an effective power Peff _t = A _t * P _u where A _t is a power ratio of the actuator, between 0 and 1.

In the present system, the power actuators make it possible to regulate the power of the heating device 11 according to descriptive data of a state of said electrical network 2 (see below). For this, each power actuator is controlled by the control module 12 so as to regulate the power of the heating means. By control, it is meant that the control module 12 is adapted to determine and impose the power ratios A _t of the power actuators according to the instructions it receives. The advantage of power actuators is to make a conventional on-off device power-adjustable. Alternatively, the heating device 11 may be a variable power electronic equipment receiving a signal from the control module 12.

It will be understood, however, that the present invention is not limited to any particular way of regulating the power of the heating means, and it will be understood that it is sufficient for the system to be configured so that the control module 12 regulates the power of the heating the heater 1 1. Management Mechanism

The descriptive data of the state of the electrical network 2 are transmitted to a management element 30 connected to the control module 12. This management element 30 is configured to control the control module 12 as a function of at least descriptive data. a state of said electrical network 2.

In other words, the management element 30 acts as a module for pre-processing data describing the state of the network 2.

The management element 30 can integrate with a control module 12 of an existing water heater, and does not require structural modification. In particular, there are only a few modifications of the control module 12 which only performs "post-processing" (see below what it consists of). It is thus easy and inexpensive to modify existing equipment. In the case of new water heaters, the management element 30 can be directly integrated into the control module 12 as an additional function, or to an energy manager of the fireplace, in order to eliminate the need for additional housing (in particular in other words, the control module 12 directly processes the data describing the state of the electrical network 2).

These data generally indicate all the information on the network load 2, the energy rate of renewable origin, the forecasts of variation of this rate, production / consumption in general, etc.

These data can be generic data obtained locally, for example of meteorological origin, which can indicate to what extent the means of production of renewable energy will be productive, but preferably it is more complex data provided for a long time. communication network 3 (typically the internet network, but also the electrical network 2) via a housing 31, 32, in particular in real time.

In the context of the present method, these data comprise data relating to the aforementioned deviation curve (CDE) which can be obtained from the information of the electric meter (s) 31 (according to the connection diagram of the photovoltaic panels (PV)) . More generally, the data received by the management element 30 includes data quantifying the surplus or deficit of non-renewable origin within the network 2. These data are on the one hand instantaneous data (production less consumption in real time ), and on the other hand forecast data, in particular daily forecast data (estimated deviation curve for the next day). These forecast data can be model-estimated data, or simply the previous day's data.

In a first embodiment, the housing 31 is an intelligent electricity meter (for example LINKY) having a Transmitter Telecom Client (TIC) integrated or not. The data used may in particular be the ICT fields such as for example: the binary state of one or more virtual contacts, the tariff index of the supplier grid and / or current distributor, the price of electricity, mobile peak notice and / or mobile tip (s), etc. In this case, and if the local network 2b includes a source of energy of renewable origin, the instantaneous data quantifying the surplus or the deficit of renewable origin are the sense of the instantaneous intensity, the variations of the EAIT indexes (energy injected) and EAST (energy withdrawn from the grid) at bidirectional meter 31 when the PV is connected downstream of the counter 31 (case of Figure 1 b). Alternatively, the instantaneous data quantifying the surplus or deficit of renewable origin are the variations of the EAIT indexes at the level of a production meter and EAST at the level of a consumption meter (see third embodiment).

In a second embodiment, the housing 32 is a "box" type internet access equipment of an Internet access provider. The box 32 is connected to the management element 30 by network connection means such as Wi-Fi, an Ethernet link, the PLC, and so on. the data can then be data built for the user of the system 1: for example, he may be assigned a certain amount of renewable energy from the network 2 to consume (for example simulating the presence of photovoltaic panels), and the housing 32 receives in real time the production data of this energy source of renewable origin. Can also be received complete weather data (wind speed, sunshine, etc.), data pre-processed on servers of an electricity supplier to optimize the overall load, etc.

In a third embodiment, the housing 32 is a power manager connected via a wired / radio link to one or more electric meters 31 associated with renewable energy production points (in particular if the energy renewable origin to one or more dedicated local delivery points). The link can be mono or bidirectional. Access to meters allows full real-time monitoring of renewable energy production and consumption of the dwelling (s), hence the availability of the instantaneous and forecast data mentioned.

The present invention is not limited to any particular type of data descriptive of a state of said power grid 2, nor to a way of providing such data. Process

The present invention relates to a method for modifying the energy consumption of a water tank 10 (of a system 1 as described above). By changing the energy consumption is meant variation of the amount of energy stored as heat in this tank 10. It will be seen later that one can also possibly change the energy capacity of a water tank 10. By energy capacity of the tank 10 is meant the maximum amount of energy stored in thermal form via hot water.

As explained, the method begins with a step (a) of receiving data describing a state of an electrical network 2, including instantaneous data and forecast data quantifying a surplus or deficit of renewable energy at within the network 2.

With these data, the management element 30 calculates an injectable power threshold on the network 2 as a function of a potential energy capacity of the water reservoir 10 and said forecast data.

By threshold of injectable power on the network, we mean a renewable energy surplus level of renewable origin acceptable at the scale of the dwelling (but in excess of the storage possibilities). In other words, where the systems mentioned previously proposed maximizing self-consumption as much as possible, the present method proposes on the contrary to voluntarily leave a certain power to be injected on the network, but at a level which will be either minimum and compatible with the constraints of the electric infrastructures. It should be noted that this threshold can be completely zero (that is to say, one returns to the maximum self-consumption) if the level of production of energy of renewable origin is sufficiently low (for example days in the case of renewable energy of photovoltaic origin) so that an integral consumption of this energy is possible. The result is visible in Figure 3a. In the example shown, the threshold is calculated at 491 W. As can be seen, energy is permanently injected into the network 2, but at a low level and constantly. Thus, we consume the same amount of energy as before, but more evenly distributed throughout the day and we avoid the peak late afternoon. This step (b) can be done once a day (in the morning, for example 6h), but it should be noted that it can be repeated to refine the value of the threshold.

In this step (b), the management element 30 begins by estimating the potential energy capacity of the water reservoir 10. Potential energy capacity is the amount of energy still stored by the reservoir 10. Assuming that the water volume in the tank 10 is constant (the hot water withdrawn is replaced by water at room temperature), this potential capacity is for example a function of a signal representative of the water temperature of the tank 10 generated by a temperature probe 20. In particular it can be given by the formula E _storage = m * Cp * (T _setpoint - _average T), where m is the mass of water stored (for example 200 kg), Cp la Specific heat capacity of water (1, 163 Wh.kg ^"1 ^{K" 1),} T _set the set temperature (e.g. 65 ° C) and T _mean the average temperature measured by the sensor 20 (e.g. 55 ° C at some point). The temperature can be instantaneous, but it is preferable to have an average temperature over a few minutes for example to avoid errors. It is possible to remove from this potential capacity an estimate of the energy that will be drawn off during the day, or simply reiterate the calculation of this potential capacity several times a day.

This potential capacity and the forecast data make it possible to calculate this threshold. The threshold must be such that the integral of the energy surplus beyond the threshold must approximate the estimated potential capacity (remaining lower). In more mathematical terms, if CDE _pre v (t) is the surplus / deficit of renewable energy expected at time t of the day ahead, so E _storage = i _{CDEpre t> threshold.} CDEprev t - seuiï) dt.

In practice, the area between the reference deviation curve (dotted line) and the deviation curve obtained through the process should be as close as possible to the potential energy capacity. The threshold value can be obtained by dichotomy between 0 and the peak power installed. Starting for example from a median value (or the threshold determined for the previous day), the energy to be stored is calculated for this threshold value and compared with the estimated potential capacity of the reservoir 10: if the calculated value is greater than the potential capacity, then the threshold must be raised, and vice versa. Some iterations are sufficient to obtain an acceptable threshold value. It should be noted that, like the potential capacity, it can be updated several times during the day.

In a step (c), the management element 30 dynamically generates a power setpoint as a function of said injectable power threshold and said instantaneous data. More precisely, a set point P (t) is calculated at any time so as to consume the difference between the current surplus of renewable energy and the threshold. For example, for a threshold at 491W, if the surplus at a time t is 1500W, then the setpoint will be set to 1009W.

In known manner, said set point is emitted in a step (d) to the control module 12 of the heater 1 1 of the water tank 10, so as to regulate the power of the heating means according to the setpoint of power (in other words impose the power instruction).

It should be noted that the power setpoint can be ignored if it is likely to disturb the comfort of the user.

Tests have shown that in the reference example mentioned, the gain on the annual injection peak is 12%. In addition, the surplus injected into the grid at a power greater than 1000W represents 188 kWh / year instead of 1480 kWh / year. Maximum threshold

Preferably, a maximum threshold of injectable power can be provided on the network 2 (it can be included in the data describing the state of the network 2 received and be determined according to a more global state of the network). This maximum threshold is a power reference threshold injected into the network 2, corresponding to an acceptable level of constraints on the electrical infrastructures. Below this threshold, infrastructures are considered protected.

If the threshold calculated in step (b) does not reach this maximum threshold (ie the EJC is able to meet a level of renewable energy injection on grid 2 lower than this threshold, in other words that if the EJC meets this threshold, it does not use all of its energy capacity), it can be provided (if the user or the operator of the network 2 orders it) to limit the power setpoint generated in step (c). In an extreme case, it can be expected (as seen in Figure 3b) to take the maximum between the calculated threshold and the predefined maximum threshold (in other words, if the calculated threshold is below the maximum threshold it is replaced by the maximum threshold). Alternatively, it may for example be provided that the maximum between the calculated threshold and an average (or other combination) of the two thresholds is taken.

This reduces the shift in consumption of the water heater from night to day, in particular to benefit from the off-peak tariff, while limiting the peak of production as much as possible. This solution allows for example, a few days before an extremely hot day anticipated, to keep some of the available storage capacity and to manage the last day optimally.

Note that the arbitrage between "forced" self-consumption and injection on the network (ie modification of the calculated threshold if it is below the maximum threshold) could thus depend on a tariff of obligation purchase price sometimes higher or lower than the selling price. The strategy would then be the minimization of the customer's energy bill (expenses - revenues).

Let SPV be the surplus of renewable origin power, T _aC hat (t) and Pvente (t) the purchase price and the sales price at time t. When the source of energy of renewable origin is connected downstream of the meter 31 (case of Figure 1 b), move the operation of the CEJ of the HC (Hollow Hours, ie the moment when the price of sale of electricity is minimal ) to t for self-consumption Spv (t) is interesting if T _aC hat (t) <Ptyte (HC). Assuming that the calculated threshold is below the maximum threshold, it can thus be expected that the replacement of the threshold calculated by the maximum threshold (calculation of the maximum of the two thresholds) is implemented only if the above condition does not exist. is not respected. Indeed, if T _aC hat (t) <Ptyte (HC) it is interesting in all cases to self-consume at most (no necessary comparison of the thresholds and therefore no limitation of the power setpoint), whereas if T _aC hat (t)> P _V ente (HC) it becomes interesting to self-consume only up to the maximum threshold (to guarantee an acceptable injection level on network 2), and to keep the "reserve" of energy capacity for off-peak hours to lighten the customer's bill. Engagement also depends on the rate of coverage of the renewable surplus.

In any case, as mentioned before, the power setpoint can be ignored if it is likely to disturb the comfort of the user.

The tests carried out by the applicant thus show that in the reference example the surplus injected into the network at a power greater than 1000W only represents 35 kWh / year.

In the case where the threshold calculated in step (b) is beyond the maximum threshold (in other words the EJC is insufficient only to achieve the desired consumption), additional load shedding mechanisms may be provided: of production (clipping), recourse to auxiliary storage means such as batteries (stationary or embedded in a vehicle, and to which charging strategies may also apply), etc.

The idea is thus to absorb over the water the surplus greater than the power setpoint through piloting, and to implement in the second spring a mechanism of clipping / storage complementary to the production if this first lever is insufficient to ensure that it is not exceeded.

Mechanism of lure

In a particularly preferred embodiment (represented by FIG. 1b) the system 1 further comprises a decoy element 21 (which is typically coincident with the control element 30) disposed between the probe 20 and the control module 12 The decoy element 21 and the management element 30 may be distinct and connected to a common energy manager 31 (as in the case of Figure 1b).

In any case, this decoy element 21 is configured to intercept and modify the signal emitted by the probe 20 so as to modify (in particular increase) the potential energy capacity of the water reservoir 10, according to the descriptive data of a state of said electrical network 2.

In other words, the decoy element 21 voluntarily distorts the temperature measurements of the probe 20, so as to trick the control module 12 and alter the regulation of the temperature of the tank 10. The signal is in fact intercepted by the lure element 21, modified and returned to the control module 12. The latter treats it as an authentic signal from the probe 20.

For example, during a water heating phase (and therefore temperature rise of the tank 10), the decoy element 21 can modify the signal sent by the probe 20 so as to make the control module 12 believe that the water is less hot than it really is. This makes it possible to exceed the second temperature threshold, and to influence the calculation of the potential energy capacity (which depends on the temperature measurement of the probe 20).

This mechanism combines very advantageously with the calculation of the power threshold injected in step (b): if the calculated threshold exceeds the maximum threshold, an "artificial" increase in the potential energy capacity via decoy can be provided, so to reduce the threshold obtained by calculation (until passing under the maximum threshold). The dichotomy can be used.

Such "overheating" mode can be used to increase the consumption of the CEJ and thus the amount of energy stored. In this mode, the decoy element 21 is configured so that the signal received by the control module 12 is representative of a temperature lower than the actual temperature of the water of the reservoir 10, when the descriptive data of a state of said electricity grid 2 are characteristic of a current glut and / or a future energy deficit of renewable origin within said electricity grid (in other words if the production of renewable origin is decreasing at short term), so as to increase the energy capacity of the water tank 10.

In particular, if the injectable power threshold on the network 2 is greater than said maximum threshold, the decoy element 21 can be used to increase the potential energy capacity of the reservoir 10 until the power threshold for injection on the network 2 obtained is equal to the maximum threshold.

Thanks to the overheating, the second temperature threshold is crossed and water at 5 or 15 ° C above the comfort temperature is stored. This makes it possible to manage days of very high production, of the type of that represented in FIG. 3c. The tests carried out by the plaintiff thus show that in the reference example, the surplus injected into the network at a power greater than 1000 W represents this time only 15 kWh / year, or only 1 1 h cumulatively.

There are many known ways to implement this element of decoy and we will refer for example to the application FR1363229 above. If the control module 12 is an advanced electronic card allowing either to adjust the set temperature according to the constraints of the electrical system or to receive it as a value or pace (typically a power manager), the decoy element 21 can be directly included in the control module 12 (as a software element).

Claims

A method of modifying the energy consumption of a water tank (10), the method being characterized in that it comprises steps of:

(a) receiving data describing a state of an electrical grid (2), including instantaneous data and forecast data quantifying a surplus or deficit of renewable energy within the network (2); (b) calculating by a management element (30) an injectable power threshold on the network (2) as a function of a potential energy capacity of a water reservoir (10) and said forecast data;

(c) generating by the management element (30) a dynamic power setpoint as a function of said injectable power threshold and said instantaneous data;

(d) sending said setpoint to a control module (12) of a heater (1 1) of the water of the tank (10), the heating device (1 1) comprising a means for heating supplied by the electricity network (2);

(e) power regulation of said heating means by the control module (12) as a function of the power setpoint.

The method of claim 1, wherein step (b) comprises estimating by the management element (30) said potential energy capacity of the water reservoir (10) as a function of a signal representative of the temperature of the reservoir water (10) generated by a temperature sensor (20).

The method according to claim 2, wherein said signal representative of the water temperature of the tank (10) is intercepted and modified by a decoy element (21) disposed between the probe (20) and the control module (12) according to said data describing a state of the electrical network (2) to be representative of a temperature lower than the actual temperature of the water of the tank (10), so as to increase the capacity potential energy of the tank (10).

4. Method according to one of the preceding claims, wherein the forecast data quantifying a renewable energy surplus or deficit within the network (2) are daily data, steps (a) and (b). being implemented at least once a day.

5. Method according to one of the preceding claims, wherein the injectable power threshold on the network (2) is such that the integral of the surplus energy at a power greater than said threshold is less than or equal to said potential energy capacity. of the water tank (10).

6. Method according to one of the preceding claims, wherein step (b) comprises the comparison of said injectable power threshold on the network (2) with a maximum threshold provided with the descriptive data of a state of a network. electric (2).

7. The method of claim 6, wherein step (b) comprises starting an auxiliary energy storage device if said injectable power threshold on the network (2) is greater than said maximum threshold.

8. Method according to one of claims 6 and 7, wherein step (b) comprises, if said injectable power threshold on the network (2) is less than said maximum threshold, the replacement of the injectable power threshold on the network (2) by a higher value between the threshold of injectable power on the network (2) as calculated and the maximum threshold.

The method of claim 8, wherein said replacement of the injectable power threshold on the network (2) is implemented only if a purchase price of renewable electricity is greater than a selling price. minimal electricity.

The method according to one of claims 6 to 9 in combination with claim 3, wherein step (b) comprises, if said injectable power threshold on the network (2) is greater than said maximum threshold, the increase by a lure element (21) of the potential energy capacity of the reservoir (10) until the injectable power threshold on the network (2) obtained is equal to the maximum threshold.

11. Method according to one of the preceding claims, wherein step (a) comprising the reception of said data describing a state of the electrical network (2) by a housing (31) from a communication network (3), the housing (31) being connected to said management element (30) or to the control module (12).

12. Method according to one of claims 1 to 10, wherein the network (2) comprises a local area network (2b) comprising local means for producing renewable energy connected downstream of a counter (31), the data predictive snapshots quantifying a renewable energy surplus or deficit within the grid (2) being consumption data provided by the meter (31).

13. Method according to one of the preceding claims, wherein the control module (12) is configured to ignore the power setpoint when a water temperature of the tank (10) is greater than a predefined threshold.

14. System (1) comprising:

- a water tank (10); - A heater (1 1) of the water tank (10), the device (1 1) comprising a heating means powered by an electrical network (2);

a temperature probe (20) configured to emit a signal representative of the water temperature of the tank (10);

a control module (12) regulating in power the heating means of said heating device (1 1);

the system being characterized in that it further comprises a management element (30) configured for implementing the method according to one of the preceding claims.