HEAT PUMP SYSTEM WITH SELF-CONSUMPTION MANAGEMENT AND DEMAND RESPONSE FUNCTIONS

Abstract

 The object the present invention is an indoor thermoregulation and sanitary water heating system configured to adapt its operation to the availability of energy.
The system receives information on the available power or energy. The thermoregulation system comprises a thermoregulation circuit wherein a heat transfer fluid flows, that exchanges heat with a heat pump. The thermoregulation circuit comprises at least one circulation pump for said heat transfer fluid and one or more terminals for indoor heating/cooling and/or for the production of sanitary water,
The terminal for the production of sanitary water is a section of the thermoregulation circuit that passes through a sanitary water storage tank with which it exchanges heat.
The sanitary storage tank is also equipped with an electric resistance immersed in the sanitary water.
Furthermore, the thermoregulation circuit may be equipped with an electrical resistance immersed in the heat transfer fluid, used as a back-up or aid of the heat pump generator for indoor heating. Heat pump and resistances are configured to activate in a coordinated manner to maximise the consumption flexibility.

Description

[0001] Object of the present invention is a heat pump system for indoor heating/cooling functions and/or for the production of sanitary water configured to maximise the self-consumption of energy from renewable sources, produced locally in uncontrollable quantities and/or to provide ancillary services for balancing the power grid (Demand Response).

[0002] More precisely, the object of the present invention is a heat pump system for indoor thermoregulation functions and/or for the production of sanitary water, designed to maximise the consumption flexibility, while containing the standing heat losses and guarantee the comfort.

[0003] Without any limiting intent, the invention therefore falls within the sector of the heat pump thermoregulation apparatuses for residential and/or industrial/commercial buildings (or the like), where "thermoregulation" should be indifferently referred to as "heating" or "cooling", provided by an electrical power supply.

[0004] It is known that a heat pump system comprises at least:

• one "refrigeration circuit" wherein a refrigerant is evaporated at low temperature, brought to high pressure, condensed and finally brought back to an evaporation pressure, and
• one "thermoregulation circuit" where a heat transfer fluid, preferably water or the like, circulates, that may be used for indoor heating/cooling via radiators, floor radiant panels, fan coils or the like. The thermoregulation circuit may comprise one or more auxiliary thermoregulating elements, adapted to heat the heat transfer fluid. Such elements are typically electrical resistances.

[0005] The heat pump system herein described further comprises:

• one apparatus for the production of sanitary hot water via dedicated heat accumulators, e. g. hot water tanks. This apparatus may be provided with a further heating element, typically a resistive element immersed in the water of the storage.

[0006] The renewable energy, intermittent and uncontrollable by its nature, is not always available when needed and is not economical to be stored; all flexible consumption systems that may adapt their consumption profile to the availability of renewable energy are therefore useful. The electricity market attributes a value to the ability to change the profile of the demand based on the availability of energy. Systems capable of consuming energy locally from renewable sources, avoiding its feed-in to the grid and its transport, or systems that adapt the consumption to a variable of the electrical grid indicative of the price or of the availability of energy are particularly useful. The share of self-produced energy or power not locally produced and fed into the grid shall be hereinafter referred to as "surplus" energy or power.

[0007] Storage water heaters are known wherein, once the target temperature is reached and in the surplus condition, are capable of activating a heating function that absorbs a power not exceeding the surplus until a second temperature is reached, which shall be herein referred to as "surplus temperature" and which is a fixed temperature greater than the target temperature.

[0008] EP2610999A2 provides for delivering energy to a heating resistance by modulating the power so as to use only the surplus power.

[0009] It is clear that such systems are useful to the extent that the consumption of self-produced energy translates into a substantially equal reduction of energy required by the grid, and any reduction in consumption does not lead to a significant reduction in comfort.

[0010] The aim of the present invention is a heat pump system for indoor thermoregulation functions and/or for sanitary water heating that is more flexible in adapting the consumptions to the availability of energy and that maximises the quantity of energy that may be stored with low heat standing losses.

[0011] Another object of the invention is to provide ancillary services for balancing the power distribution grid (Demand Response), by increasing the consumption of electrical energy that may be stored in the form of thermal energy and stored in the indoor thermoregulation system, where thermoregulation means indoor and/or sanitary water heating and/or cooling

[0012] Another object of the invention is to describe a coordinated management method of the electrical loads aimed at achieving the set objectives.

[0013] These and other objects, which shall appear clear hereinafter, are achieved with a heat pump system according to the independent claims. Other objects may also be achieved by means of the additional features of the dependent claims.

Figure 1 represents a possible embodiment of a thermoregulation system.

Figure 2 represents a second possible embodiment of a thermoregulation system.

Figure 3 represents a second possible embodiment of a thermoregulation system.

[0014] According to the prior art, a thermoregulation system comprises:

• at least two thermoregulating elements 11, 11a, 11b, 12, 23, of which a first thermoregulating element 11, 11a, 11b is conveniently a heating pump and a second thermoregulating element 12, 23 is suitably a resistance,
• one thermoregulation circuit wherein a heat transfer fluid flows.
• The thermoregulation circuit comprises:

• means 13, 14 for conveying the heat transfer fluid through a heat exchanger at least with the first thermoregulating element 11, 11a, 11b and selectively towards a sanitary circuit 2 and/or a primary circuit 3;
• the sanitary circuit 2 that conveys the heat transfer fluid through a fluid-water exchanger 22, with a sanitary storage tank 21, hereinafter referred to as "storage";
• the primary circuit 3 leading the heat transfer fluid through fluid-air heat exchangers 31, 32 where the indoor air is the fluid to be thermoregulated.

[0015] A control unit is also provided (not shown in the figure) comprising means for controlling the thermoregulating elements 11, 11a, 11b, 12, 23, and capable of controlling the means 13, 14 for the circulation of the heat transfer fluid. The control unit is configured to receive temperature readings at least from the storage 21, from the rooms to be thermoregulated and from the heat transfer fluid. The control unit is further configured according to the prior art to receive a consumption flexibility request signal, the signal being one of a surplus local power signal, a request for consuming a quantity of surplus power, a request for changing the consumptions based on to the needs of the grid.

[0016] The thermoregulation system may comprise one electrical resistance 12 as a thermoregulating element, hereinafter referred to as "thermoregulation resistance" 12, for shortness. The thermoregulation resistance 12 is configured to intercept and heat the fluid in the thermoregulation circuit, upstream of a branch towards the sanitary circuit 2, and towards the primary circuit 3. The thermoregulation resistance 12 is used in the prior art as an auxiliary heating element to make up for the heating function when the heat pump 11, 11a, 11b is no longer sufficient for the needs of the system, or if it may no longer remain in operation or if it must limit the thermal power generated due to the reaching its operating limit conditions (for example as a result of an excessive temperature difference between evaporator and condenser or when the maximum temperature obtainable for the heat transfer fluid is reached, a limit which depends on the type of refrigerant fluid).

[0017] It has been found that the electrical resistances may be activated more advantageously than the heat pump when the consumption flexibility request requires almost instantaneous intervention times, such as for example in the case of a flexibility request from the grid (Demand Response). In fact, the heat pump technology takes several minutes to reach its maximum power and, after a shutdown, has minimum re-ignition times (of a few minutes, for example 10), below which it is not advisable to go, in order to limit the wear of the compressor with too frequent cycles. Also, in this case the electrical resistances may be activated more advantageously than the heat pump.

[0018] The primary circuit 3 may comprise an accumulation of heat transfer fluid (Figure 3) hereinafter referred to as "buffer" 41, for shortness. The buffer 41 increases the thermal capacity and therefore the possibility of storing heat.

[0019] The combination that comprises one buffer 41 and one thermoregulation resistance 12 is particularly advantageous.

[0020] Conveniently, one means 34 for regulating the circulation of the heat transfer fluid from the buffer 41 to the heat exchangers 31, 31 may be associated with the buffer 41. In this case the buffer 41 may also carry out functions of hydraulic separator between generator and system and the temperature of the buffer 41 may be regulated by varying the fluid flowing out of the buffer 41 towards the heat exchangers 31, 32. A further buffer resistance 42 may be associated with the buffer 41 in a heat exchange relationship therewith. The means 34 for regulating the circulation of the heat transfer fluid from the buffer 41 to the heat exchangers 31, 32 may be a pump.

[0021] The thermoregulation system may comprise an electrical resistance 23 as a thermoregulating element, hereinafter referred to as "sanitary resistance" 23, for shortness. The sanitary resistance 23, that is configured to heat water in the storage 21 and may be placed inside the storage 21.

[0022] In the thermoregulation system according to the invention, the control unit detects a signal indicative of a consumption flexibility request and enters an operating mode called "flexible consumption" wherein it adapts the operation of the thermoregulating elements to the flexibility request.

[0023] When the consumption flexibility request is a request for storing energy, the control unit gets at least two electrical loads to cooperate simultaneously by choosing between the first thermoregulating element 11, 11a, 11b and the sanitary resistance 23 or alternatively, in the models where they are present, the thermoregulation resistance 12, or the buffer resistance 42. The cooperation may comprise the simultaneous activation. The availability of two electrical loads that may be activated together or separately allows selecting one among at least three power levels.

[0024] The at least two thermoregulating elements 11, 11a, 11b, 12, 23, 42 activated in response to a flexibility request remain active as long as the flexibility request persists or the respective temperature to be regulated has reached the temperature target.

[0025] The at least two thermoregulating elements 11, 11a, 11b, 12, 23, 42 activated together may be the sanitary resistance 23 that heats the storage 21 and the heat pump 11, 11a, 11b which may simultaneously carry out the thermoregulation of the primary circuit 3, either by heating or cooling, or the heat pump 11, 11a, 11b may collaborate with the sanitary resistance 23 to heat the storage 21 via the fluid-water exchanger 22.

[0026] The at least two thermoregulating elements 11, 11a, 11b, 12, 23, 42 activated together may also be the thermoregulation resistance 12 that cooperates with the heat pump 11, 11a, 11b when this is in heating mode.

[0027] The thermoregulating elements 11, 11a, 11b, 12, 23, 42 may be activated simultaneously, any combination being possible. The availability of three electrical loads that may be activated together or separately allows selecting one of at least six power levels. According to a preferred embodiment, the thermoregulation resistance 12 has a nominal power different from that of the sanitary resistance 23, in this way the combinations of active loads: heat pump 11, 11a, 11b, sanitary resistance 23, thermoregulation resistance 12 determine seven possible levels of power consumption. In fact, the consumption levels of each thermoregulating element 11, 11a, 11b, 23, 12 being called A, B, C, the possible combinations are A, AB, B, AC, BC, ABC, C.

[0028] As is known, the heat pump 11, 11a, 11b is unable to heat beyond its critical temperature, in this case two resistances 12, 23 still remain available, which allow at least three different consumption levels A, B, AB to be selected. Naturally, the solution may be generalised to n resistances and both the sanitary resistance 23 and the thermoregulation resistance 12 may be multiple resistances comprising several independent elements.

[0029] In the so-called "flexible consumption" operating mode, the control unit may change the normal temperature target, by adopting a "flexible threshold" aimed at increasing the consumption flexibility. An increase in the temperature target allows more energy to be stored.

[0030] Naturally in the case of cooling, cold accumulates and the flexible threshold is lower than the temperature target. In the text, by energy storage in the form of thermal energy both cases of hot and cold storage are comprised. Therefore, "to store heat" also comprises the concept of storing cold fluid.

[0031] The flexible threshold may be at least one of the following temperatures: temperature of the storage 21, buffer 41, heat transfer fluid or indoor temperature. Such accumulation of heat may therefore take place in the sanitary storage 21, for example by defining a flexible threshold of storage temperature higher than the storage target temperature. Similarly, the accumulation of heat may be in the primary circuit and/or in the buffer 41 defining a flexible temperature threshold of the heat transfer fluid or even a specific temperature for the buffer 41.

[0032] A third flexible threshold may be set for the indoor temperature, that may undergo limited variations compared to the normal setpoint set by the user. In particular, it may be further increased in case of heating and further reduced in case of cooling, to store energy.

[0033] In the same way, the thermoregulation system may reduce its consumption, if requested by the grid. In this case the flexible thresholds are lower than the respective target temperatures in the case of heating and higher in the case of cooling.

[0034] In flexible consumption mode with heat storage, it is useful to limit the consumption to a "surplus power" P_sur, equal to the locally generated and not requested power surplus or equal to a target power assigned by the grid. In particular, it is useful to limit the consumption in the situation in which the target temperature has been met, but not yet the flexible threshold.

[0035] In order to further maximise the consumption flexibility, the heat pump 11, 11a, 11b may be of the variable speed type. In this case the heat pump 11, 11a, 11b is modulated so that the total consumption of the system or the total consumption of the user is lower than or equal to the surplus power P_sur.

[0036] According to a possible embodiment, the combination of thermoregulating elements 11, 11a, 11b, 23, 12, 42 to which the maximum power level among those lower than the surplus power is associated, is selected in order to maximise the consumption without exceeding the surplus power P_sur.

[0037] In flexible consumption mode, not all load combinations are always possible, as each storage 21, 41 or circuit 2, 3 is subject to a maximum temperature (minimum in case of cooling). For example, it is possible to turn on the sanitary resistance 23 as long as the storage 21 remains below the flexible threshold for the storage, it is possible to turn on the thermoregulation resistance 12 or the heat pump 11, 11a, 11b, as long as the heat transfer fluid remains below the flexible threshold for the heat transfer fluid.

[0038] The means 13, 14, 34 for the circulation of the heat transfer fluid through the sanitary circuit 2 and/or primary circuit 3 may be selectively controlled to transfer heat to the sanitary circuit 2 or to the primary circuit 3 based on their respective residual capacities of storing heat. The residual capacity by the sanitary circuit 2 of storing heat is determined by the difference between the flexible threshold of the storage and the detected temperature, that of the primary circuit 3 is determined by the difference among the temperature between the flexible threshold for the temperature and the actual temperature of the thermoregulated indoor. The flexible threshold for the indoor temperature is related to the maximum thermal comfort temperature. By way of an example, if the temperature of the heat transfer fluid is close to its flexible threshold, it is possible to act on the circulation means 13, 14, 34, favouring the inflow of the heat transfer fluid to that between sanitary circuit 2 and/or primary circuit 3 and/or indoor heat exchangers 31, 32 which has a temperature further away from their flexible threshold. It is then possible to send the heat transfer fluid to the primary circuit 3 as long as the indoor temperature remains within a comfort range.

[0039] It is possible to use multiple flexibility thresholds at the same time, for example a flexibility threshold for the temperature of the heat transfer fluid together with a flexibility threshold for the indoor temperature.

[0040] Models that have a buffer 41 in the primary circuit 3 have a greater storage capacity and it is also possible to define a surplus temperature of the buffer 41.

[0041] It is possible to send the heat transfer fluid to the sanitary circuit 2 as long as the temperature of the storage 21 remains below the flexible storage threshold. The self-consumption may be increased by adopting a flexible threshold for the storage and/or the buffer 41 and/or the room temperature.

[0042] The means 13, 14, 34 for the selective circulation of the heat transfer fluid through the sanitary circuit 2 and/or primary circuit 3 comprise one pump 14, the means for the selection may be a three-way valve 13 configured to divert the path of the heat-transfer fluid towards the sanitary circuit 2 and/or the primary circuit 3. The circulation pump 14 of the primary circuit, and the possible pump 34 from the buffer 41 to the indoor heat exchangers 31, 32 may be a variable flow pump and adapted to vary the flow, enabling to increase the heat exchange from the primary circuit 3 towards the storage or indoor spaces or buffer 41 or towards the indoor heat exchangers 31, 32 and therefore allowing a greater energy storage during the period when there is a power surplus.

[0043] According to a preferred embodiment, the thermoregulating elements 11, 11a, 11b, 12, 23, 42 are managed by giving priority to the self-consumption requests of the surplus and/or flexibility requests by the grid.

[0044] Some embodiments of the consumption flexibility mode are described below, where consumption flexibility refers to all the flexibility functions aimed at favouring both the self-consumption of energy from renewable source and the adaptation to flexibility requests by the power grid, regardless of how the latter are conveyed.

[0045] The following embodiments illustrate possible ways to define the flexible temperature threshold of the heat transfer fluid.

[0046] According to a possible embodiment, the user may set the heat pump 11, 11a, 11b so that it controls the temperature of the heat transfer fluid according to the set indoor temperature, hereinafter for shortness "indoor setpoint", and possibly to the detected indoor temperature. In this case, a change in the indoor setpoint translates into a change in the target temperature of the heat transfer fluid and therefore in the possibility of increasing the energy consumption by storing more heat. In the case of variable speed heat pump 11, 11a, 11b, a change in the indoor setpoint may translate into a change in the power consumption of the heat pump 11, 11a, 11b.

[0047] According to some preferred methods, the changed indoor setpoint may be:

a) different from the normal setpoint for a settable change, hereinafter settable "offset"

b) a settable value

c) a settable value based on time slots or energy cost.

[0048] The indoor setpoint thus changed is a flexible threshold for the indoor temperature.

[0049] According to a possible embodiment, the user may set the heat pump 11, 11a, 11b and possibly the resistance 23 and the buffer resistance 42 so that they regulate the temperature of the heat transfer fluid and that of the possible buffer 41 to a target temperature not dependent from the indoor setpoint. In this case, in consumption flexibility mode, the consumption is determined from the flexible threshold of the heat transfer fluid and from the possible buffer 41. Such flexible threshold may be:

a) the target temperature of the heat transfer fluid plus a predetermined offset,

b) settable, possibly based on the type of heat exchangers 31, 32 (for example between 60-75°C for radiator system 31 and between 37°-50°C for underfloor system 32, and between 40°-60° for fan coils,

c) the target temperature plus a settable offset and in any case not higher than the maximum value set for the type of heat exchangers 31, 32.

[0050] According to a possible embodiment, the primary circuit 3 comprises a heat transfer fluid storage 41 called "buffer" and the control unit is set up to detect the temperature of the buffer 41. In this case, a flexible threshold is defined for the buffer. The embodiment with buffer 41 is particularly advantageous if a thermoregulation resistance 12 is provided.

[0051] The flexible threshold of the storage 21 may be set by the manufacturer or selectable by the user. In both cases the value may be:

a) higher than the target temperature for a settable offset

b) a settable value independent of the target temperature

c) a settable comfort temperature value based on a time or energy cost range.

[0052] According to a possible embodiment, the combination of thermoregulating elements 11, 11a, 11b, 23, 12 to be activated in flexible consumption mode may follow priorities set by the user.

[0053] If in flexible consumption mode, following the detection of a power surplus, the sanitary resistance 23 is to be activated with priority, the control unit modifies the thermostating of the sanitary resistance 23 from the target temperature to the flexible threshold for the storage 21. This operating mode, in case of requested flexibility for self-consumption of surplus power, is called "SELF CONSUMPTION DHW/DR".

[0054] If in flexible consumption mode the heat pump 11, 11a, 11b or the thermoregulation resistance 12 is to be activated with priority, the control unit modifies the target temperature of the heat transfer fluid in the ways described above: by going directly to the flexible threshold for the heat transfer fluid or by changing the indoor setpoint. This operating mode, in case of requested flexibility for self-consumption of surplus power, is called "SELF CONSUMPTION CH/COOL/DR".

[0055] If the activation of a thermoregulating element is not sufficient to obtain the flexibility level that is required by the network or is necessary to consume the surplus power, the control unit also activates a further lower priority thermoregulating element.

[0056] The system may therefore simultaneously activate multiple thermoregulating elements to carry out the self-consumption of power from renewable source with the advantage of increasing the possibility of self-consuming the greatest possible percentage of self-produced renewable power.

[0057] In one possible operating mode, the sanitary resistance 23 may be active in consumption flexible mode, and the heat pump 11, 11a, 11b may activate following the modification of the indoor setpoint in both heating and cooling mode (i.e. it is possible to carry out self-consumption of renewable energy or respond to Demand Response requests by using multiple thermoregulation functions at the same time).

[0058] If more than one thermoregulating element is turned on, in case the surplus becomes negative, one of the thermoregulating elements, activated with the aim of maximising the self-consumption or minimising the thermal energy generation cost, will be turned off or modulated first (e.g. it may be decided to keep on the resistance even if with an efficiency equal to one and to turn off the compressor, with efficiency greater than one, if this, due to the different value of electrical power absorbed by the two generators, could lead to either greater self-consumption or to a lower cost of the thermal energy produced).

[0059] The heat exchangers 31, 32 between primary circuit and indoor space may include: radiators, fan convectors or fan coils, underfloor heating/cooling system.

Claims

1. Computer implemented method for controlling a thermoregulation system,

the thermoregulation system comprising

at least two thermoregulation elements (11, 11a, 11b, 12, 23, 42) comprising a heat pump (11, 11a, 11b) and at least one electrical resistance (12, 23, 42) and a thermoregulation circuit wherein a heat transfer fluid flows, the thermoregulation circuit comprising:

- means (13, 14, 34) for the circulation of the heat transfer fluid through a heat exchanger with a first thermoregulation element (11, 11a, 11b) and selectively towards a sanitary circuit (2) and/or a primary circuit (3);

- the sanitary circuit (2) configured for conveying the heat transfer fluid through a fluid-water heat exchanger (22), with a storage tank (21);

- the primary circuit (3) configured to convey the heat transfer fluid through at least one fluid-air heat exchanger (31, 32) in a heat exchange relationship with indoor spaces and optionally comprising a heat transfer fluid storage buffer (41);

the thermoregulation system further comprising a control unit capable of receiving a

- a signal indicative of a request for consumption flexibility, the signal being one of: a local surplus power P_sur signal, a request for consuming a quantity of surplus power P_sur, or a request for changing the consumptions based on to the needs of the grid;

- temperature readings from:

- the heat transfer fluid,

- the storage tank (21),

- and the indoor spaces wherein the at least one fluid-air heat exchanger (31, 32) are located,

- and, if present, from the buffer (41);

the method comprising the following steps:

a) receiving a signal indicative of a request for consumption flexibility,

b) selecting a combination of thermoregulation elements (11, 11a, 11b, 12, 23, 41) which allows to attain the maximum level of combined power consumption below the surplus power Psur; activating the selected combination as long as there is the request for consumption flexibility or the temperature to be regulated has reached a corresponding temperature target.

2. Method according to claim 1, wherein step b comprises:
selectively controlling the means (13, 14, 34) for the circulation of the heat transfer fluid to transfer heat to the sanitary circuit (2) or to the primary circuit (3) based on their respective residual capacities of storing heat.

3. Method according to claim 2, wherein the means (13, 14, 34) for the circulation of the heat transfer fluid comprise at least one variable flow pump configured to increase the heat exchange from the primary circuit (3) towards the storage tank (21) or buffer (41) or towards the indoor heat exchangers (31, 32).

4. Method according to any between claims 1, 2 or 3 wherein step b of claim 1 comprises:
replacing the temperature target of at least one among the heat transfer fluid, the storage (21), of any buffer (41) and/or of the indoor space with a flexible temperature threshold is to be replaced.

5. Method according to any claim from 1 to 4, wherein step b) of claim 1 includes activating at least two among at least three thermoregulation elements of which:

- the heat pump (11, 11a, 11b) may heat or cool the heat transfer fluid,

- a first electrical resistance (12) configured to heat the heat transfer fluid,

- a second electrical resistance (23) configured to heat the storage (21),

- or two among at least four of which a fourth thermoregulation element is a third electrical resistance (42) configured to heat the buffer (41).

6. Method according to any claim from 1 to 5 wherein in step b) of claim 1 electrical resistances (12, 23, 42) are prioritised vs the heat pump (11, 11a, 11b) in case the signal is a request from the grid for consuming a quantity of surplus power P_sur.

7. Method according to claim from 1 to 5, further comprising a step of modulating at least one thermoregulation element so that the total power consumption of the thermoregulation system is equal to the surplus power P_sur.

8. Method according to any one among claims 1 to 7 further comprising the steps of:

- detecting user set rankings associated with the thermoregulation elements (11, 11a, 11b, 12, 23, 42),

- selecting the thermoregulation elements (11, 11a, 11b, 12, 23, 42) according to the user set rankings.

9. Method according to any one of claims from 3 to 8further comprising a step of

setting the flexible threshold value, either by adding an offset to the target temperature or to the environment setpoint, or by

calculating a flexible threshold based on time of use or tariff.

10. Method according to any one of claims from 3 to 8 further comprising a step of
setting the flexible threshold for the heat transfer fluid or for the buffer (41) to a value depending on the type of heat exchangers (31, 32), or adding an offset to the target temperature and imposing that the result is not higher than a value depending on the type of heat exchangers (31, 32).

11. Control unit for a thermoregulation system configured to control:

- at least two thermoregulation elements (11, 11a, 11b, 12, 23, 42) comprising a heat pump (11, 11a, 1 1b) and at least one electrical resistance (12, 23, 42),

- means (13, 14) for conveying the heat transfer fluid through a heat exchanger with the first thermoregulation element (11, 11a, 11b) and selectively towards a sanitary circuit (2) and/or a primary circuit (3);

the control unit configured to receive:

- a signal indicative of a consumption flexibility request, the signal being one of: a local surplus power P_sur signal, a request for consuming a quantity of surplus power P_sur, or a request for changing the consumptions based on to the needs of the grid;

- temperature readings from the heat transfer fluid, from the storage (21) and from the environment wherein the fluid-air heat exchanger (31, 32) is located,

and further configured to implement the method according to claims 1 to 10.

12. Processor-readable memory means comprising instructions which, if executed by a processor-based electronic control unit, cause the execution of the steps of one of claims 1 to 10.

Drawing