FR3140668A3 - WATER HEATER CAPABLE OF RESPONDING TO NETWORK CONDITIONS - Google Patents

Abstract

The present invention relates to an electric water heater provided with a vertically developed storage tank and upper and lower resistive heating elements and, optionally, a lower heating element constituted by the condenser of a heat pump . The water to be heated enters the lower part and is sucked in from the upper part. The water heater is configured to operate in several user-selectable heating modes, in which all modes guarantee compliance with a given temperature but are different in terms of control logic and consumption level, and is in Besides capable of flexible consumption depending on the state of the network. Figure for the abstract: [Fig. 1a].

Description

WATER HEATER CAPABLE OF RESPONDING TO NETWORK CONDITIONS

An electric storage water heater for domestic water or technical water for space heating is described below.

A method of operating an electric storage water heater is also described.

Compared to instantaneous water heaters, storage water heaters have the advantage of requiring less energy. However, storage water heaters have certain disadvantages. For example, they are subject to heat losses, which are greater the higher the average water temperature in the storage tank.

These water heaters traditionally include electrical resistances, hereinafter referred to as "resistors". We also know storage water heaters which use a heat pump as a heating means, in addition to or instead of resistance elements.

The need to reduce electricity consumption has led to the development of "smart" water heaters equipped with algorithms that take into account past events to adjust the storage temperature. Thus, when the probability of hot water withdrawal is low, the tank is maintained at a low average temperature, while when the probability of hot water withdrawal is high, the tank temperature is maintained at a higher average temperature. .

With the gradual transition from fossil energy sources to renewable energy, the supply of electricity on the grid is subject to the availability of wind or photovoltaic energy, resources which are inherently intermittent and uncontrollable. Furthermore, the electricity generation and distribution network faces a quantitatively very different power demand at different times, for example at different usage peaks during a day.

The network therefore finds itself in a situation where demand and supply of energy must be balanced, and it is demand which must adapt to supply. Currently, it is necessary for household appliances to be able to adapt their consumption, i.e. their demand, to network conditions. Storage water heaters are known whose heating element management algorithms take into account an unbalanced situation in the electrical network.

EP3662210B1 describes an electric storage water heater with vertical development, the water heating of which is controlled by an electronic controller which takes into account the user's habits. The water heater maintains the thermostat temperature at a low level during periods when no withdrawal is planned. The learning of the withdrawal profiles is based on an estimation of the withdrawals according to temperature variations. The method allows significant reductions in consumption in normal operation, but does not learn to respond to network signals in an optimized way, for example how to respond to imbalances to which the network is subject, possibly by adapting to the conditions of shortage or overabundance of energy on the network.

Document US11300325B2 describes an electric storage water heater, with vertical development, equipped with an electrical resistance in an upper zone and another in a lower zone of the storage tank. Resistance management is ensured by an electronic controller which takes into account conditions of shortage or overabundance of energy on the network. A temperature hysteresis is applied to either the upper element or the lower element. When the network is balanced, the water heater does not adopt any consumption rationalization strategy. In the event of an energy shortage (energy demand exceeds availability and there is an imbalance with respect to demand), the energy consumption of the water heater is reduced based on a heuristic algorithm that takes into account previous water withdrawals. The reduction is achieved by reducing either the activation threshold or the deactivation threshold; in one figure is shown a reduction of the corresponding hysteresis. In the event of an overabundance of energy (imbalance towards production), the water heater increases the temperature threshold to stop the heating elements at a value which does not take into account the real needs of the user and therefore does not exclude that the increase in consumption results in wasted energy.

On the contrary, it is desirable that the increase in consumption leads to energy storage which allows a subsequent reduction in consumption.

Document US20130200168A1 describes a water heater having an upper heating element and a lower heating element capable of operating in normal mode and in economy mode in which the thermostating temperature is reduced depending on the user's habits. The water heater, optionally through an associated external controller, is capable of responding to a network condition of energy shortage or surplus by activating or deactivating the heating elements.

WO2019060 describes a water heater having a top resistance and a bottom resistance capable of receiving signals from the grid indicating a condition of energy shortage or overabundance and responding to an energy availability signal by switching to a high-power operation mode and a power shortage signal when switching to a low-power operation mode. The document does not teach user selectable modes.

In general, it is necessary to regulate the water heater so as to reduce energy consumption under normal conditions and to have an additional level of flexibility to respond to unbalanced network conditions without unduly penalizing comfort. Comfort is defined as a level of performance that ensures that water is available at the programmed temperature when the user wants it. There is no known water heater that can both optimize consumption under normal conditions and be configured to have flexible consumption in response to network conditions.

These objectives, as well as others which will become clear later, are achieved by a method and apparatus conforming to the main method claims and an apparatus (or system) conforming to the main device claims.

Other objectives may also be achieved through additional features of dependent claims.

The following is a description of an electric storage water heater which comprises a vertically developed tank or storage in turn comprising an upper zone from which the heated water is drawn and a lower zone into which the water to heat is introduced. The lower and upper zones are heated by respective heating elements and equipped with respective temperature sensors. For the sake of brevity, this configuration will be called "two zones" in the rest of the document.

A method of managing the operation of a “two-zone” type electric storage water heater is also described.

Figures 1.a, 1.b, 1.c, 1.d show different views of a possible embodiment of an electric resistance water heater;

Figures 2.a, 2.b and 2.c show a second possible embodiment of a water heater with electric heating elements and a heat pump;

Figures 3.a and 3.b present tables of correspondence between hourly rates and particular network conditions;

There presents a table of values taken by a variable in different possible operating modes.

Other characteristics of the present invention will be better highlighted by the following descriptions of possible embodiments, in accordance with the claims and illustrated, purely by way of example and not in a limiting manner, using the figures. It should be noted that the invention is not limited to the construction details, examples and what is illustrated in the figures; other embodiments are possible without departing from the scope of the claims. The terms used in the description should not be considered limiting. The terms "receive", "read", "detect", "receive" are used in a broad sense to indicate the reception of information, including information contained in signals coming from outside, extracted from a memory or received as input from a user interface. Likewise, the terms "communication" or "connection" are not limited to communication over physical links or cables.

With reference to the attached drawing tables, reference number 1 indicates a water heater comprising a vertically developed storage tank 10 with an upper part 11 and a lower part 12.

In the upper part 11 of the storage tank 10 there is at least one first heating element 41, and in the lower part 12 of the storage tank 11 there is at least one second heating element 51, 61, hereinafter referred to as elements or elements heating. The at least one upper element 41 may comprise an electric heating element, the at least one lower element 51, 61 may comprise an electric heating element 51 and/or a condenser 61 of a heat pump 6.

Near the respective heating elements 41, 51, 61 there is a first temperature sensor or upper temperature sensor 42, which detects a higher temperature called "Tdome", respectively a second temperature sensor or lower temperature sensor 52, which detects a lower temperature "Tbottom". The temperature sensors 42, 52 may be conventional temperature sensors (e.g. thermistors).

A water heater 1 equipped only with heating elements 41, 51 will be called in the rest of the text electric water heater or electric model, to distinguish it from the "hybrid" model which also includes a condenser 61 of a heat pump 6 .

Cold water enters the storage tank 10 through a first opening 2 which introduces it near the bottom 12, while heated water, directed towards the user, exits through a second opening 3 near the top of the storage tank. storage 10. In this way, under stable conditions, the stratification of temperatures contributes to the water leaving the tank 10 being at a higher temperature.

The water heater 1 also includes a controller 5 which regulates the operation of the heating elements 41, 51, 61.

The controller 5 includes memory media and is capable of receiving temperature readings taken by the temperature sensors 42, 52 and a set temperature "Tset" defined by the user (via the user interface 7).

The controller 5 is configured to calculate a control temperature for each heating element 41, 51, 61. The control temperatures are equal to the temperature sensor readings or a weighted average. Heating elements can have the same control temperature.

The controller 5 can be an electronic control unit comprising:

a memory containing the program instructions and parameters,

the means of executing instructions and calculations,

means for controlling the heating elements and receiving signals from the outside.

The controller 5 is configured to receive a set temperature, Tset, defined via a user interface 7.

The user interface 7 may be integrated into the water heater and include means of manual input such as buttons or dials and/or be external and include means of sending input data to the controller 5 which is configured to receive them. When integrated with the water heater 1, the user interface 7 can be assembled in one piece with the controller 5, as shown in Figures 1.a, 1.b, 2.a and 2.b.

The upper part 11 of the storage tank is heated directly by at least one upper heating element 41 and indirectly, by convection effect, by at least one lower heating element 51, 61. The at least one upper heating element 41 has the upper temperature Tdome as the control temperature, where the upper temperature Tdome is a significant component in a weighted average of the temperature sensor readings. The at least one lower heating element 51, 61 has as control temperature the lower temperature Tbottom or alternatively an average temperature "Tavg" which is obtained as an average between the dome temperature Tdome and the lower temperature Tbottom. Preferably, this average is a weighted average, and more preferably, the weight “Wdome” of the dome temperature is less than the weight “Wbottom” of the bottom temperature.

According to a preferred embodiment, the weight Wdome of the dome temperature is between 0.25 and 0.40, for example 0.3. At least one of the weights Wdome, Wbottom is a parameter stored in the memory of the controller 5, the other being able to be calculated accordingly or also being saved.

A thermostating temperature “Ttarget” is set for each heating element 41, 51, 61.

In a possible embodiment, the controller 5 defines a common thermostating temperature Ttarget for at least the heating elements 41, 51. The thermostating temperature Ttarget of each heating element 41, 51, 61 is included in a range between a temperature minimum temperature “Tmin” and a maximum temperature “Tmax” (Tmin ≤ Ttarget ≤ Tmax).

The maximum temperature Tmax is a factory setting, which can be modified by the user, and can vary, for example, between 55°C and 85°C. It preferably reaches higher values in the presence of a thermostatic mixer. It preferably reaches higher values in the presence of a thermostatic mixer.

The minimum temperature Tmin is the temperature considered acceptable to ensure the comfort of sanitary use, it can be between 37°C and 42°C, for example around 40°C. Thermostating at temperatures above the minimum temperature Tmin makes it possible to mix the water supplied with cold water, which has the advantage of increasing the volume of water that can be supplied beyond the volume of the storage tank. storage.

• pour l’élément chauffant supérieur 41 : Ttarget – ThystDome /2 ;
• pour l’au moins un élément chauffant inferieur 51, 61 : Ttarget – Thyst/2.

The heating elements 41, 51, 61 activate when the respective control temperature falls below the thermostating temperature Ttarget minus a hysteresis value and deactivate at the thermostating temperature Ttarget. At least one upper heating element 41 has an upper hysteresis ThystDome (it activates at a temperature Ttarget - ThystDome) while the at least one lower heating element 51, 61 has a lower hysteresis Thyst (it activates at a temperature Ttarget - Thyst). In general, the hysteresis can be different for each heating element. The median value between the activation and deactivation temperatures is therefore:

• for the upper heating element 41: Ttarget – ThystDome /2;
• for the at least one lower heating element 51, 61: Ttarget – Thyst/2.

• pour l’élément chauffant supérieur 41 : Ttarget + ThystDome /2 ;
• pour l’au moins un élément chauffant inferieur 51, 61 : Ttarget + Thyst/2.

Translating all temperature values to the hysteresis amplitude, all of the above also applies to the case when the heating elements turn on at the thermostating temperature Ttarget and turn off when the temperature rise is equal to the Thyst hysteresis, ThystDome. In this case, the median value between the activation and deactivation temperatures is therefore:

• for the upper heating element 41: Ttarget + ThystDome /2;
• for the at least one lower heating element 51, 61: Ttarget + Thyst/2.

In an embodiment illustrated schematically in Figure 2.a, 2.b, the at least one lower heating element 51, 61 comprises a lower heating element 51 and a condenser 61 of a heat pump 6.

In the example illustrated, the condenser 61 comprises a pair of windings 611, 612 positioned respectively above and below the lower resistor 51.

The heat pump 6 has greater energy efficiency than the heater 51, but it can only heat up to a maximum threshold temperature Thp; a typical value for the pump threshold temperature Thp is around 55°C. Beyond this Thp threshold, heating is only provided by heaters 41, 51.

In the embodiment of Figures 2.a, 2.b, 2.c., the lower resistance 51 can operate in relay mode with the heat exchanger 61 of the heat pump 6. In relay mode below the Thp threshold, the lower element used is the condenser 61, above, the lower element used is the resistor 51.

Relay operation between the heat exchanger 61 of the heat pump 6 and the lower heater 51 makes it possible to reduce instantaneous and electrical energy consumption, the heat pump 6 having an energy efficiency greater than that of the heater 51.

When the heat pump 6 and the lower heating element 51 operate in relay, it is preferable that the control temperature for both is the average temperature Tavg for more efficient operation of the water heater 1. According to some embodiments in water heater models 1 including a condenser 61 as a single lower element or accessory, for all lower heating elements 51, 61 the control temperature is the average temperature Tavg.

In electric-only models, the lower resistance is preferably controlled by the temperature Tbottom measured by the lower temperature sensor 52.

In preferred embodiments, the upper 41 and lower 51 heating elements are never activated together and, even more preferably, the upper heating element 41 has priority over the lower heating element 51. In other words , in these embodiments, priority is always given to heating the water contained in the upper part 11 of the storage tank 10 (that is to say the water intended to be supplied first).

To meet the opposing requirements of reducing consumption and ensuring a sufficient quantity of hot water, the water heater 1 has at least two heating modes that can be selected according to needs.

The heating modes, hereinafter referred to as "mode" for brevity, provide water at a set temperature Tset, but differ in the control logic of the heating elements 41, 51, 61 and in consumption. Heating modes can preferably be selected via user interface 7.

In a first heating mode called "Manual" or "Comfort", the water heater 1 sets the thermostating temperature Ttarget equal to the set temperature Tset for all the resistive heating elements 41, 51 and for the heat pump, the where applicable, if the setpoint temperature Tset is not higher than the threshold temperature Thp. The set temperature Tset varies between the minimum temperature Tmin and the maximum temperature Tmax. In the first comfort heating mode:

the upper 41 and lower 51 resistors never activate together,

the upper resistance 41 has priority over the lower resistance 51,

if there is a condenser 61 as a lower element, the lower resistance 51 operates in relay with the heat pump 6.

According to a possible embodiment, the heating modes further comprise a second heating mode which is an optimized mode called "I-memory". The second I-memory mode differs from the first comfort mode in that the thermostating temperature Ttarget is equal to an optimized temperature Tmem which varies over time and is a function of the memorized draft profile (the draft profile being defined by the volume and temperature over a given period). The optimized temperature Tmem can vary from the minimum temperature Tmin to the maximum temperature Tmax. Methods for calculating this optimized temperature are defined in the literature; to simplify, a method is described in document EP2366081B1.

In Figure 2, the water heater 1 comprises at least one resistive heating element 41, 51 and an element consisting of the condenser 61 of a heat pump 6, capable of heating up to a maximum temperature threshold Thp.

In particular in the embodiments described here which include a heat pump 6, the water heater 1 can also include a third heating mode which is a sustainable mode called “Green” and/or a fourth heating mode which is a fast mode called “Fast”.

The third heating mode, Green mode, has the priority of limiting electricity consumption and only uses the heat pump 6, while the resistive elements 41, 51 are always deactivated. In the third Green mode, the thermostating temperature Ttarget is equal to the minimum between the setpoint temperature Tset and the temperature threshold Thp of the heat pump 6.

The fourth Fast mode has the priority of heating quickly and differs from the first Comfort mode in that the lower heating element 51 is activated not in relay, but at the same time as the heat pump 6, with the only additional constraint in relation to to the heat pump 6 that the upper heating element 41 is and remains off. In the fourth Fast mode, the heat pump 6 is preferably controlled with the average temperature Tavg, the lower heating element 51 is preferably controlled with the lower temperature Tbottom.

In the third Green mode and the fourth Fast mode, the thermostating temperature Ttarget is equal to the setpoint temperature Tset. It is possible to achieve a fifth mode called "I-memory green" which is equal to the third Green mode with the thermostating temperature Ttarget equal to the minimum between an optimized temperature Tmem and the temperature threshold Thp of the heat pump 6. even, it is possible to achieve a sixth mode called "I-memory fast" which is equal to the fourth Fast mode with the thermostating temperature Ttarget equal to the optimized temperature Tmem. There presents in a table the values of the thermostating temperature Ttarget for each heating mode.

Optionally, for each heating mode, the regulator 5 can calculate a thermostating temperature TtargetS, TtargetI51, TtargetI61 specific respectively for the upper heating element 41, for the lower resistive heating element 51 and for the possible condenser 61, in which the thermostating temperatures TtargetI51, TtargetI61 of the lower heating elements 51, 61 are a function of the thermostating temperature TtargetS of the upper heating element 41.

From what has been said above it is clear that each heating mode is configured to reach a temperature selected by a user Tset or a threshold temperature Thp of a heating element which is a condenser (61) of a heat pump. heat (6) or an optimized temperature Tmem.

According to certain possible variants, at least two hysteresis values are defined: an upper hysteresis "ThystDome" for the upper element 41 and a lower hysteresis "Thyst" for the at least one lower element 51, 61. It has been observed that the adoption of different hysteresis values for the upper heating element 41 and the lower heating element 51, 61 can further reduce consumption or, for the same consumption, improve comfort. In what follows, the ThystDome hysteresis designates the hysteresis of one or more upper elements, the lower Thyst hysteresis that of one or more lower elements 51.

In particular, in the forms of water heater 1 with only electric heating elements 41, 51, it is advantageous to have a higher lower hysteresis Thyst (for example between 2°C and 21°C, preferably between 4°C C and 21°C, preferably between 12°C and 18°C, in particular 15°C) and a lower ThystDome upper hysteresis (for example between 1°C and 20°C, preferably between 4°C and 20°C °C, alternately between 3°C and 9°C, in particular 5°C).

On the other hand, in the embodiments where the water heater 1 includes a condenser 61 of a heat pump 6 as a lower heating element, the situation is reversed and it is more convenient to have a lower hysteresis Thyst plus low (for example in a range between 1°C and 20°C, preferably between 3°C and 9°C, in particular 5°C) and a higher hysteresis at the level of the ThystDome dome (for example in a range between 2°C and 21°C, preferably between 9°C and 18°C, in particular 12°C).

Indeed, in designs where water heating is carried out solely by means of electrical resistances, it is preferable to avoid the activation of the lower resistance 51 by small momentary temperature fluctuations due to the entry of cold water caused by small water withdrawals and subsequent water turbulence. Higher hysteresis makes the lower resistance 51 more stable and less sensitive to small turbulences. To compensate for the lower sensitivity, a lower hysteresis at the ThystDome is very useful, making the upper resistor 41 very sensitive to even slight turbulence, so that it activates quickly to ensure the correct temperature at outlet 3 of water heater 1.

In models which also include a condenser 61 as a lower heating element, it is desirable to use the heat pump 6 as much as possible and to reduce the use of the heating elements 41, 51. It is therefore appropriate here to make so that the heat pump 6 is activated even in the event of small fluctuations in the water temperature, by adopting a lower Thyst hysteresis smaller than the upper ThystDome hysteresis.

Optionally, electric model hysteresis is used in heat pump models when the average temperature Tavg or the thermostat temperature Ttarget is higher than the heat pump threshold Thp. Under these conditions, the heat pump 6 does not contribute and the water heater 1 can be controlled as if it were an electric model.

According to a possible embodiment, the water heater 1 is powered by energy from an electrical network and is configured to operate with at least two heating modes chosen from the first "Comfort" mode, the second "I-" mode. memory", the third mode "Green", the fourth mode "Fast", the fifth mode "I-memory Green", or the sixth mode "I-memory Fast" and to receive the selection of the heating mode from a user interface. The controller 5 is further configured to deactivate the heating elements 41, 51, 61 and/or modify their control parameters depending on a condition (detected, estimated or predicted) of shortage or overabundance of energy and the mode of heating selected.

Under ideal conditions, the demand for electricity and the energy injected into the electricity grid balance each other. In practice, these values vary relative to each other, giving rise to unbalance conditions that cause frequency and voltage to drift. Beyond an admissible range, the network does not tolerate this imbalance and, to avoid damage or widespread outages, or in any case to respect voltage and frequency standards, network managers must necessarily disconnect users or generators. Conditions of shortage are those of a significant imbalance in relation to energy demand, and conversely, conditions of glut are those of a significant imbalance in relation to the energy injected into the network.

In network conditions of shortage (imbalance with respect to demand) and/or overabundance (imbalance with respect to supply) of energy, several levels of severity can be defined and, preferably, the water heater 1 is configured to respond to at least two different severity levels (hereinafter referred to as "level") for a network condition of energy shortage and/or overabundance.

In a possible embodiment, the controller 5 is capable of managing the following severity levels, listed in increasing order of severity:

a first level of scarcity indicating a moderate imbalance in relation to demand, called "Load shed",

a second level of shortage indicating a strong imbalance in relation to demand, called "Critical peak event",

a third level of scarcity indicating a very strong imbalance in relation to demand with a risk of disconnection, called "Grid emergency".

a first level of overabundance indicating a moderate imbalance in relation to supply, called "Load up",

a second level of glut indicating a strong imbalance in relation to supply, called "Advanced load up".

It should be noted that the response of water heater 1 does not guarantee an immediate and certain change in consumption, but implies a change in probable consumption with a probability that increases with the level of severity and the maintenance of the state of the network over time. This is due to the fact that, preferably, the regulator 5 of the water heater 1 implements rules which guarantee the maintenance of a minimum level of comfort and to the physical constraints of the thermodynamic system. If several water heaters 1 are present in the same network, in large numbers, the overall effect is to have some variation, so that the objective of balancing the network is achieved.

According to a first embodiment, the water heater 1 is capable of receiving and the controller 5 is configured to respond to signals S, which indicate a condition of shortage or overabundance of energy in the network according to at least some of the five levels of defined severity, the first, second and third levels of shortage "Load shed", "Critical peak event", "Grid emergency", the first and second levels of overabundance "Load up", "Advanced load up".

Several known protocols allow a device connected to the network to receive signals S corresponding to at least some of the severity levels listed. Some protocols include a severity level and a required response time in a signal S.

As a non-limiting example, the water heater 1 can be configured to receive signals compatible with the CTA2045 protocol. In general, similar protocols are becoming more and more popular as they are used to implement so-called "Demand response" services, which allow the energy demand of a period to be flexible in order to follow the offer.

The water heater 1 can receive signals S directly from the network or indirectly through other devices which receive them from the network.

According to possible embodiments, signals S are sent to the water heater 1 by a local device which manages the energy consumption of one or more devices.

In a second embodiment, the water heater 1 responds to an hourly energy price schedule, and price values above or below an average value correspond to one of the severity levels. Without losing its generality, the time program can be predefined in the water heater 1, updated manually by a user, updated periodically or received in real time by the water heater 1 which is configured to receive and manage a hourly price signal. As a non-limiting example, the water heater 1 can be configured to receive hourly price signals using the JA-13 protocol.

A single water heater 1 can be configured to receive S signals and to have defined time programs. The first, second and third shortage levels, "Load shed", "Critical peak event" and "Grid emergency" take priority over all other settings, including time programs. Preferably, responding to a network condition takes priority over time schedules. In general, however, water heater 1 gives priority to S signals from the network.

1. la sélection d'un mode de chauffage "Confort", "I-memory", "Green", "Fast", "I-memory Green", "I-memory Fast" est reçue d'une interface utilisateur, qui définit une logique de commande pour chaque élément chauffant,
2. un premier signal S est reçu avec l'un des niveaux de gravité d'une situation de pénurie ou de surabondance d'énergie dans le réseau et une durée, le niveau de gravité appartenant à la liste des premier, deuxième et troisième niveaux de pénurie "Load shed", "Critical peak event", "Grid emergency", et des premier et deuxième niveaux de surabondance "Load up", "Advanced load up",
3. En fonction du mode de chauffage et du niveau de gravité sélectionnés, une éventuelle nouvelle température de thermostatisation Ttarget est définie pour tous les éléments chauffants et/ou une éventuelle nouvelle hystérésis Thyst pour les éléments chauffants inférieurs,

• en cas de troisième niveau de pénurie "Grid emergency", les éléments de chauffage sont désactivés,
• en cas de deuxième niveau de pénurie "Critical peak event" dans le modèle de pompe à chaleur, les chauffages 41, 51 sont désactivés, dans le cas d'un chauffe-eau électrique, le chauffage inférieur 51 est désactivé,
• si un nouveau signal S arrive, l'étape 2 est répétée
• si un nouveau mode de chauffage "Confort", "Green", "I-memory", "Fast", "I-memory Green", "I-memory Fast" est sélectionné ou si une nouvelle température de consigne Tset est réglée, l'étape 3 se poursuit avec le nouveau mode de chauffage ou la nouvelle valeur de réglage de la température de consigne Tset pour la durée restante,
• à la fin de la durée associée au signal S, la logique de commande du mode de chauffage sélectionné est rétablie.

The water heater 1 described above can operate as follows:

1. the selection of a heating mode "Comfort", "I-memory", "Green", "Fast", "I-memory Green", "I-memory Fast" is received from a user interface, which defines a control logic for each heating element,
2. a first signal S is received with one of the severity levels of a situation of shortage or overabundance of energy in the network and a duration, the severity level belonging to the list of the first, second and third shortage levels "Load shed", "Critical peak event", "Grid emergency", and the first and second levels of overabundance "Load up", "Advanced load up",
3. Depending on the selected heating mode and gravity level, a possible new thermostating temperature Ttarget is defined for all heating elements and/or a possible new hysteresis Thyst for the lower heating elements,

• in the event of a third level of shortage "Grid emergency", the heating elements are deactivated,
• in the event of a second level of shortage "Critical peak event" in the heat pump model, the heaters 41, 51 are deactivated, in the case of an electric water heater, the lower heater 51 is deactivated,
• if a new signal S arrives, step 2 is repeated
• if a new heating mode "Comfort", "Green", "I-memory", "Fast", "I-memory Green", "I-memory Fast" is selected or if a new setpoint temperature Tset is set, step 3 continues with the new heating mode or the new setpoint temperature adjustment value Tset for the remaining duration,
• at the end of the duration associated with the signal S, the control logic of the selected heating mode is reestablished.

The water heater 1 can be configured to respond to an hourly energy price schedule by associating lower price values with severity levels corresponding to the glut condition, higher price values with levels of lower severity, and higher prices at severity levels corresponding to the shortage condition, higher price values at higher severity levels. Preferably, no severity level is associated with prices in an intermediate range.

1. un mode de chauffage est reçu d'une interface utilisateur 7 qui définit une logique de commande pour chaque élément chauffant ;
2. on lit en mémoire ou on reçoit en entrée ou du réseau une grille tarifaire horaire contenant des prix d'énergie associés chacun à une période de la journée appelée tranche horaire, où l'ordre entre l'étape 1 ou 2 est indifférent :
3. les prix minimum et maximum parmi tous ceux associés aux différents créneaux horaires sont identifiés ;
4. des niveaux de gravité sont sélectionnés ;
5. l'intervalle entre le prix minimum et le prix maximum est divisé en autant de sous-intervalles qu'il y a de niveaux de gravité sélectionnés, plus un éventuel intervalle intermédiaire ;
6. les intervalles sont classés par prix croissant et :

• les intervalles de prix les plus bas sont associés aux conditions de surabondance d'énergie par ordre de gravité décroissante et de prix croissant ;
• les intervalles de prix les plus élevés sont associés aux conditions de pénurie d'énergie par ordre de gravité décroissante et de prix décroissant ;
• l’intervalle de prix intermédiaire n'est associé à aucun niveau de gravité ;

1. pour chaque nouvelle tranche horaire où le prix n'appartient pas au niveau intermédiaire, les éléments chauffants sont désactivés et/ou les paramètres de contrôle sont modifiés en fonction du mode de chauffage actif et du niveau de gravité.

A method for optimizing consumption according to a timetable is described using Figures 3.a and 3.b. The method includes the following steps:

1. a heating mode is received from a user interface 7 which defines control logic for each heating element;
2. we read from memory or we receive as input or from the network an hourly tariff schedule containing energy prices each associated with a period of the day called time slot, where the order between step 1 or 2 is indifferent:
3. the minimum and maximum prices among all those associated with the different time slots are identified;
4. severity levels are selected;
5. the interval between the minimum price and the maximum price is divided into as many sub-intervals as there are selected severity levels, plus a possible intermediate interval;
6. the intervals are ordered by increasing price and:

• the lowest price intervals are associated with energy glut conditions in order of decreasing severity and increasing price;
• the highest price intervals are associated with energy shortage conditions in order of decreasing severity and decreasing price;
• the intermediate price interval is not associated with any severity level;

1. for each new time slot where the price does not belong to the intermediate level, the heating elements are deactivated and/or the control parameters are changed depending on the active heating mode and severity level.

Figure 3.a shows a representation according to a possible embodiment in which the selected severity levels are a first and a second level of shortage "Load shed", "Critical peak event" and a first level of overabundance "Load up". Figure 3.b shows a second possible realization in which all defined severity levels are selected.

Some preferred implementations for changing control parameters based on severity levels are described below.

It has been said that in order to respond to different severity levels, water heater 1 is configured to change the control parameters; according to a preferred embodiment, these parameters include at least the thermostating temperature Ttarget. Preferably, the control parameters include the Thystdome upper hysteresis and/or the Thyst lower hysteresis.

For the first "load shed" rarity level, the water heater 1 sets the thermostating temperature Ttarget to the minimum value between a comfort threshold Tcomfort and the previous thermostating temperature Ttarget:

Ttarget = min (Tcomfort, Ttarget)

The comfort threshold Tcomfort is a value located in the comfort range of around 40°C-50°C, preferably around 42°C.

In all heating modes, the thermostating temperature Ttarget can already be lower than a threshold Tcomfort = 42 °C, either because the user has set it to the minimum value, or because it is set by the algorithm in the case of the second I-memory mode. In all other cases, a real reduction in consumption is obtained.

In certain possible embodiments, the water heater 1, in order to respond to the second shortage level "Critical peak event", combines both the described reduction of the thermostating temperature Ttarget and the deactivation of the lower heating element 51 , and in the case of a heat pump model, also deactivates the upper heating element 41, heating only with the heat pump. This answer applies to all heating modes.

The water heater 1, to meet the third level of rarity "Grid emergency", can turn off all the heating elements and/or adjust the thermostating temperature Ttarget to a value just above the average network water temperature, for example example 16°C. In this case, functionality is no longer guaranteed; the third level of scarcity “Grid emergency” indicates the risk of a power outage or an hourly energy cost that the user is not ready to bear.

According to a possible embodiment, the lower hysteresis under normal network conditions is greater than or equal to 4°C and the water heater 1, to respond to the first level of "Load up", increases the average temperature in the lower part by in relation to the thermostating temperature Ttarget, this by reducing the lower hysteresis Thyst, which corresponds to increasing the temperature at which the elements restart. For example, the hysteresis can be reduced to a value less than or equal to 3°C. It should be noted that if the hysteresis was set as the turn-off threshold, the hysteresis would be increased to achieve the same effect of increasing the average temperature.

In response to the second level of overabundance "Advanced load up", in addition to increasing the average temperature in the lower part, by reducing the lower hysteresis Thyst, the water heater 1 can increase the thermostating temperature Ttarget up to the maximum temperature Tmax. In the case of the third "Green" mode, the thermostating temperature Ttarget is limited above the heat pump temperature threshold Thp.

It should be noted that the response to the gravity level maintains the essential characteristics of the heating mode, for example if, in the second I-memory mode, the thermostating temperature Ttarget is 40 °C, a gravity level "Load up " results in a reduction in lower hysteresis (i.e. a slight increase in the average temperature in the lower section compared to the thermostating temperature Ttarget), but not an increase in thermostating at unnecessary temperatures .

That is to say, the controller 5 is configured so that the response to the gravity levels is not a change from one heating mode to another heating mode, but a modification of the selected heating mode. However, the response to the severity levels, is combined with the control logic determined by the selected heating mode, determining a modified logic which depends on either the selected heating mode or the gravity level.

Any reference to a user interface is to be understood broadly and includes any device capable of receiving input from a user and sending it to the controller 5, in particular, but not limited to, a physical, dedicated user interface included in the water heater, the interface of a smartphone or other device that is not part of the water heater 1, but from which the water heater 1 is configured to receive input into any known mode, including wireless mode, or a voice command sensor

Claims (1)

Water heater (1) powered by energy from an electrical network, the water heater comprising

• a storage tank (10) developed vertically, having an upper part (11) and a lower part (12) with which are associated respectively upper (42) and lower (52) temperature probes and at least one respectively upper heating element ( 41) and lower (51, 61) to heat the liquid in the storage tank (10),
• an interface (7) for selecting one of at least two heating modes (Comfort, I-memory, Green, Fast, I-memory green, I-memory fast) differing from each other in the control logic of the heating elements ( 41, 51, 61),
• a controller (5) of the heating elements (41, 51, 61), capable of receiving readings from the temperature sensors (42, 52), the selected heating mode (Comfort, I-memory, Green, Fast, I-memory green, I-memory fast), and implementing the logic for controlling the heating elements (41, 51, 61) provided by the selected heating mode, in particular to thermostat the heating elements (41, 51, 61) at a thermostating temperature Ttarget,

the water heater (1) being characterized in that the controller (5) is configured to deactivate the heating elements (41, 51, 61) and/or modify their control parameters in response to a condition of the electrical network, detected and/or estimated and/or predicted shortage or overabundance of energy and by the fact that the resulting operation is a function of both the condition of the electrical network and the heating mode selected by the user.
2.A water heater (1) according to claim 1, wherein responding to a power shortage or overabundance condition includes changing the control parameters of the heating elements (41, 51, 61).
3.Water heater (1) according to any one of the preceding claims in which the control parameters modified in response to a network condition comprise at least one thermostating temperature Ttarget common to all the active heating elements.
4.A water heater (1) according to any preceding claim, wherein the network condition of energy shortage and/or energy glut can be associated with severity levels, and the controller (5) is configured to meet at least two of the following severity levels listed in ascending order for each condition:

• a first level of shortage (Load shed),
• a second level of shortage (Critical peak event),
• a third level of shortage (Grid emergency)
• a first level of overabundance (Load up),
• a second level of overabundance (Advanced load up)

5.Water heater (1) according to claim 4, in which the controller (5) is configured to set a new thermostating temperature Ttarget for all the heating elements, and/or a possible new hysteresis Thyst is set for the lower heating elements in depending on the severity level noted.
6.Water heater (1) according to one of claims 4 or 5 configured to respond to the first shortage level (Load shed) by adjusting the thermostatization temperature Ttarget to the minimum value between a comfort threshold Tconfort and the previous thermostatization temperature Ttarget, according to the following formulas
Ttarget = min (Tcomfort, Ttarget)
where the comfort threshold Tconfort is a value between 40°C and 50°C, preferably around 42°C.
7.Water heater (1) according to claim 6, configured to respond to the second shortage level (Critical peak event) by implementing the response to the first shortage level (Load shed) and in addition:

• if the heating elements include a heat pump (6), by deactivating all the resistive elements (41, 51),
• otherwise by deactivating at least one of the lower resistive elements (51).

8.Water heater (1) according to any one of claims 4 to 7 configured to have a Thyst hysteresis of the lower heating elements (51, 61):

• in models whose lower elements are only resistive, in a range of 4°C to 21°C and preferably at 15°C,
• in models with at least one heat pump condenser, within a range of 4°C to 20°C and preferably 5°C as the lower heating element,
• and to respond to the first level of overabundance (Load up) by bringing the Thyst hysteresis of the lower elements to a value less than or equal to 3°C.

9.Water heater (1) according to claim 8 configured to respond to the second level of overabundance (Advanced load up) by implementing the response to the first level of overabundance (Load up) and in addition:

• if it is equipped with resistive heating elements only, by setting the thermostating temperature Ttarget to a predefined maximum temperature Tmax,
• if it is equipped with at least one heat pump (6) and a sustainable heating mode (Green; I-memory green) has been selected by limiting the use of the heating elements to the heat pump only ( 6) and by setting the thermostating temperature Ttarget equal to the minimum between a maximum temperature Tmax set for thermostating and a maximum temperature threshold Thp which can be reached by the heat pump (6).

10. Water heater (1) according to one of claims 2, 3, 4, 5, 6, 7, 8 or 9 configured to receive signals (S) that the controller (5) can process and which transmit a condition network and possibly the severity level.
11. Water heater (1) according to one of claims 4, 5, 6, 7, 8, 9 or 10, configured to respond to an hourly energy price program, associating the lower price values with the levels severity corresponding to the state of glut, to increase the price and decrease the severity level, and at higher prices the severity levels corresponding to the state of shortage, to increase the cost and increase the severity level.
12. Method for heating a liquid in a water heater (1) according to one of claims 3 to 10, the method comprising:
step 1: receive from a user interface (7) the selection of a heating mode (Comfort, I-memory, Green, Fast, I-memory green, I-memory fast) defining a control logic for each heating element ,
step 2: receive a first signal (S) with a severity level associated with a condition of shortage or overabundance of energy in the network and a duration, the severity level belonging to the following list: a first shortage level ( Load shed), a second level of shortage (Critical peak event), a third level of shortage (Grid emergency), a first level of overabundance (Lead up), and a second level of overabundance (Advanced load up),
step 3: depending on the selected heating mode and the severity level, define a possible new thermostating temperature Ttarget for all the heating elements and/or a possible new hysteresis Thyst for the lower heating elements,

• - in the event of a third level of shortage (Grid emergency), deactivate the heating elements or set the thermostat temperature Ttarget to a value just above the average network water temperature, for example 16°C,
• - in the event of a second level of shortage (Critical peak event), if the heating elements include a heat pump, deactivate all the resistive elements (41, 51),
• - otherwise, deactivate at least one of the lower resistive elements (51)
• - if a second signal (S) arrives, repeat step 2,
• - if instead a new heating mode (Comfort, I-memory, Green, Fast, I-memory green, I-memory fast) is selected or if a new setpoint temperature is set, continue step 3 with the new heating mode or the new setpoint temperature setting for the remaining period of time.

13. Method of heating a liquid in a water heater (1) according to hourly rate programming, the water heater (1) being in accordance with any one of claims 3 or any claim dependent on claim 3 , the method comprising the following steps:
step 1: reception of a user interface (7) of a heating mode defining a control logic for each heating element,
step 2: reading from memory or reception at the input or from the network of an hourly price grid, the order between steps 1 or 2 being irrelevant,
step 3: divide the interval between the minimum price and the maximum price into as many subintervals as there are total severity levels plus a possible intermediate interval,
step 4: sort the intervals by increasing price and associate them with severity levels by associating price intervals below glut conditions in descending order of severity and increasing price and price intervals above shortage conditions in descending order of severity and decreasing price, leaving an intermediate interval which is not associated with any level of severity,
step 5: for each new time interval where the price does not belong to the intermediate interval, deactivate the heating elements and/or modify their control parameters depending on the active heating mode (Comfort, I-memory, Green, Fast, I-memory green, I-memory fast) and the severity level (Load shed, Critical peak event, Grid emergency, Load up, Advanced load up).