SYSTEM AND METHOD FOR CONTROLLING A FLUID VECTOR TEMPERATURE IN ORDER TO HEAT A BUILDING

Abstract

A system for heating a building, including a heat generator to heat a carrier fluid, at least one radiating element for transferring heat to a thermal load included in a building, a delivery conduit for transferring the carrier fluid from the heat generator to the radiating element, a return conduit for transferring the carrier fluid from the radiating element to the heat generator, a three-way valve arranged along the delivery conduit and connected to the return conduit, the three-way valve being operable to mix the carrier fluid in the delivery conduit to the carrier fluid in the return conduit, a plurality of temperature sensors arranged to measure the temperature of the carrier fluid and a temperature of the environment outside the building, and a control unit operatively connected to the heat generator, to the three-way valve and to the temperature sensors.

Claims

1-15. (canceled)

16. A system for heating a building comprising: a heat generator to heat a carrier fluid, at least one radiating element for transferring heat to a thermal load included in a building, a delivery conduit for transferring the carrier fluid from the heat generator to the radiating element, a return conduit) for transferring the carrier fluid from the radiating element to the heat generator, a three-way valve arranged along the delivery conduit and connected to the return conduit, the three-way valve operable to mix the carrier fluid in the delivery conduit to the carrier fluid in the return conduit, a plurality of temperature sensors arranged to measure the temperature of the carrier fluid and a temperature of the environment outside the building, and a control unit operatively connected to the heat generator, the three-way valve and the temperature sensors, wherein the control unit is configured for: a) acquiring a temperature of the carrier fluid in the delivery conduit downstream of the three-way valve with respect to the direction of the flow of the carrier fluid in the delivery conduit, b) acquiring a temperature of the carrier fluid in the return conduit upstream of the three-way valve with respect to the direction of the flow of the carrier fluid in the return conduit, c) acquiring a temperature of the environment outside the building, d) estimating a first target temperature of the carrier fluid in the delivery conduit downstream of the three-way valve, based on a simplified model of the system calculated as a function of the temperature of the external environment, e) actuating at least one among the heat generator and the three-way valve to generate a periodic perturbation in the temperature of the carrier fluid downstream of the three-way valve, f) determining a second target temperature of the carrier fluid in the delivery conduit downstream of the three-way valve based on a temperature difference between the temperature of the carrier fluid in the delivery conduit and the temperature of the carrier fluid in the return conduit based on said perturbation, g) combining the first target temperature and the second target temperature to obtain a total target temperature, h) actuating at least one among the heat generator and the three-way valve to bring the carrier fluid (T.sub.W) in the delivery conduit downstream of the three-way valve to the total target temperature, and i) reiterating steps e) to h) until reaching a difference in target temperature between the temperature of the carrier fluid in the delivery conduit and the temperature of the carrier fluid in the return conduit.

17. The system according to claim 16, wherein the control unit is configured for determining the second target temperature implementing a control not based on a model, selected among perturb and observe, extremum seeking and sliding mode.

18. The system according to claim 17, wherein the control unit is configured for identifying the achievement of the target temperature difference as a maximum or minimum point of the temperature difference between the temperature of the carrier fluid in the delivery conduit and the temperature as a function of the perturbation of the periodic perturbation in the temperature.

19. The system according to claim 16, wherein the control unit defines the simplified model as a relationship between the temperature difference of the carrier fluid in the conduits and the temperature of the carrier fluid in the delivery conduit adapted to the temperature of the environment outside the building.

20. The system according to claim 19, further comprising an irradiation sensor suitable for measuring a solar irradiation to which the building is subjected, and wherein the control unit is configured to modify the simplified model of the system based on the measured solar irradiation.

21. The system according to claim 19, wherein the control unit stores the temperature measurements of the carrier fluid and of the temperature of the outside environment, and is configured to define the simplified model of the system based on such stored measurements.

22. The system according to claim 19, wherein the control unit is configured for connecting to an external entity to acquire meteorological information, and modify the estimate of the first target temperature carried out based on the simplified model of the system based on the meteorological information.

23. The system according to claim 16, wherein the control unit is configured for: detecting a temperature associated with at least one selected portion of the building, limiting the total target temperature to a first limit value or increasing the total target temperature to a second limit value to keep the temperature of the at least one selected portion of the building within a range of permitted values.

24. The system according to claim 23, wherein the control unit comprises a controller connected to a further sensor adapted to measure the temperature associated with the at least one selected portion of the building, the controller being configured for: determining first limit value as an acceptable maximum value of the temperature of the carrier fluid in the delivery conduit that keeps the temperature of the selected portion of the building within a higher threshold value.

25. The system according to claim 24, wherein the temperature measured by the further sensor is associated with a portion of the building having an average temperature higher than an average temperature of the building.

26. The system according to claim 23, wherein the control unit comprises a second controller connected to a second further sensor adapted to measure a second temperature associated with at least one second selected portion of the building, the controller being configured for: determining a second limit value as an acceptable minimum value of the temperature of the carrier fluid in the delivery conduit that keeps the temperature of the selected portion of the building within a lower threshold value.

27. The system according to claim 26, wherein the second temperature measured by the second further sensor is associated with a second selected portion of the building having an average temperature (lower than an average temperature of the building.

28. The system according to claim 16, wherein the control unit comprises a valve controller, connected to the three-way valve, configured for: adjusting an operating condition of the three-way valve to mix the carrier fluid from the heat generator and the carrier fluid in the return conduit to obtain the carrier fluid in the delivery conduit downstream of the three-way valve at total target temperature.

29. The system according to claim 16, wherein the control unit comprises a temperature sensor connected to the delivery conduit for measuring a temperature of the carrier fluid output from the heat generator, and a generator controller, connected to the heat generator, to the valve controller and to the temperature sensor, the generator controller being configured for: adjusting the operation of the heat generator to change the temperature of the carrier fluid output from the heat generator so as to obtain the carrier fluid in the delivery conduit downstream of the three-way valve at total target temperature with the three-way valve in a desired operating condition.

30. A method of controlling a system for heating a building, the system comprising a heat generator to heat a carrier fluid; at least one radiating element for transferring heat to a thermal load included in a building, a delivery conduit for transferring the carrier fluid from the heat generator to the radiating element, a return conduit for transferring the carrier fluid from the radiating element to the heat generator, and a three-way valve arranged along the delivery conduit and connected to the return conduit, the three-way valve operable to mix the carrier fluid in the delivery conduit to the carrier fluid in the return conduit, the method comprising the steps of: a) acquiring a temperature of the carrier fluid in the delivery conduit downstream of the three-way valve with respect to the direction of the flow of the carrier fluid in the delivery conduit, b) acquiring a temperature of the carrier fluid in the return conduit upstream of the three-way valve with respect to the direction of the flow of the carrier fluid in the return conduit, c) acquiring a temperature of the environment outside the building, d) estimating a first target temperature of the carrier fluid in the delivery conduit downstream of the three-way valve, based on a simplified model of the system calculated as a function of the temperature of the external environment, e) actuating at least one among the heat generator and the three-way valve to generate a periodic perturbation in the temperature of the carrier fluid downstream of the three-way valve, f) determining a second target temperature of the carrier fluid in the delivery conduit downstream of the three-way valve based on a temperature difference between the temperature of the carrier fluid in the delivery conduit and the temperature of the carrier fluid in the return conduit based on said perturbation, g) combining the first target temperature and the second target temperature to obtain a total target temperature, h) actuating at least one among the heat generator and the three-way valve to bring the carrier fluid in the delivery conduit downstream of the three-way valve at the total target temperature, and i) reiterating steps e) to h) until a target temperature difference is reached between the temperature of the carrier fluid in the delivery conduit and the temperature of the carrier fluid in the return conduit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The invention will be described hereinafter with reference to some examples, provided for explaining and not limiting purposes, and illustrated in the attached drawings. These drawings illustrate different aspects and embodiments of the present invention and, where appropriate, reference numerals illustrating structures, components, materials and/or elements that are similar in different figures are indicated by similar reference numerals.

[0057] FIG. 1 is a basic scheme of a building in which a heating system according to an embodiment of the present invention is installed;

[0058] FIG. 2 is a block diagram of the heating system according to an embodiment of the present invention, and

[0059] FIG. 3 is a flow diagram of a control procedure that can be implemented by the control unit of the heating system of FIG. 2.

[0060] FIG. 4 is a flow diagram of a procedure for seeking an optimum value not based on a model included in the control procedure of FIG. 3;

[0061] FIG. 5 illustrates graphs of the progression of operating parameters of the heating system according to an embodiment of the present invention.

[0062] FIG. 6 is a flow diagram of an alternative control procedure able to be implemented by the control unit of the heating system of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0063] Whereas the invention can undergo various modifications and alternative constructions, some preferred embodiments are shown in the drawings and will be described hereinafter in detail. However, it should be understood that there is no intention to limit the invention to the specific embodiment illustrated, but, on the contrary, the invention intends to cover all of the modifications, alternative constructions, and equivalents that are encompassed by the scope of the invention as defined in the claims.

[0064] The use of “for example”, “etc.”, “or” indicates non-exclusive alternatives without limitation unless otherwise indicated. The use of “includes” means “includes, but not limited to” unless otherwise indicated.

[0065] With reference to FIGS. 1 and 2, a building 1 is described in which a system for controlling the temperature in a building, in particular a heating system 20 according to an embodiment of the present invention, is implemented.

[0066] The building 1 comprises a plurality of portions of building separated from one another and that will be indicated with the term rooms 10 hereinafter for the sake of brevity. The rooms 10 can be of mutually different shape and volume and, moreover, groups of rooms 10 can be arranged at different heights inside the building. In the example in FIG. 1, four rooms 10 are shown, arranged on two levels. For example, the building 1 is a residential or commercial building, and each of the rooms 10 corresponds to a different apartment or office/commercial enterprise.

[0067] In order to adjust a temperature in each of such rooms 10, the heating system 20 comprises a plurality of radiating elements 21—for example radiators, fan coils, fan heaters, radiating floor and/or ceiling panels, etc. In particular, in each room 10 it is possible to arrange one or more radiating elements 21, each of which is in fluid connection with a heat generator 23—for example, a boiler —through a water distribution network 25. The distribution network 25 allows the circulation of a carrier fluid—for example, water—inside the heating system 20.

[0068] As known, the carrier fluid is heated by the heat generator 23 to a heating temperature T.sub.H and, when it reaches a radiating element 21, it gives up heat to the room 10 in order to obtain a desired room temperature T.sub.A, in general different—for example, higher—than an external temperature T.sub.E of the external environment 30 in which the building 10 is located. In other words, a difference between the desired room temperature T.sub.A for the room 10 and the external temperature T.sub.E of the external environment 30 corresponds to a thermal load for the radiating element 21. Advantageously, the heating system 20 can consider other environmental factors to determine the thermal load, like for example solar irradiation, presence/absence, force and direction of wind, and presence/absence of precipitation, etc.

[0069] As can be seen in FIG. 2, the distribution network 25 comprises a delivery conduit 251 and a return conduit 253. The delivery conduit 251 allows a flow of ‘hot’ carrier fluid—schematically indicated by an arrow in FIG. 2—to be transferred from the heat generator 23 to the radiating elements 21, and possibly to other elements (not illustrated) of the heating system 20 like a boiler/cistern for hot sanitary water. On the other hand, the return conduit 253 allows a flow of ‘cold’ carrier fluid—schematically indicated by an arrow in FIG. 2—to be transferred from the radiating element 21 to the heat generator 23.

[0070] Advantageously, a pump 40 adapted to pump the carrier fluid through the distribution network 25 is arranged on the delivery conduit 251.

[0071] Moreover, a three-way valve 50, which is also coupled in fluid connection with the return conduit 253 is also arranged on the delivery conduit 251. For example, the three-way valve 50 is arranged between the heat generator 23 and the pump 40 along the delivery conduit 251. The three-way valve 50 can be actuated to mix the ‘hot’ carrier fluid output from the heat generator with the ‘cold’ carrier fluid in the return conduit 253, so as to adjust—in particular, lower—a temperature of the carrier fluid in the delivery conduit 251 downstream of the three-way valve 50, indicated as mixed carrier fluid hereinafter, with respect to the direction of the flow of the carrier fluid in the delivery conduit 251.

[0072] Preferably, a thermostat valve 60 is arranged on the delivery conduit 251 at each radiating element 21, so as to allow a user to adjust a heat exchanged by the radiating element 21 with the room 10 in which it is arranged.

[0073] Optionally, the delivery conduit 251 and the return conduit 253 can be selectively coupled in fluid connection through a by-pass valve 70 that connects together respective ends of the delivery conduit 251 and of the return conduit 253, in order to make a return path towards the heat generator 23 for the carrier fluid selectively available.

[0074] Additionally, the heating system 20 comprises an electronic control unit 80 operatively connected at least to the heat generator 23 and to the three-way valve 50 to control the operation of the heating system 20 as described in the rest of the present document.

[0075] A plurality of sensors 90 is connected to the control unit 80 to provide operating information of the heating system 20 and/or status information of the building 1. In the example considered, a first temperature sensor 90A is provided coupled with the delivery conduit 251 upstream of the three-way valve 50 to measure the temperature T.sub.H of the hot carrier fluid, a second temperature sensor 90B is provided coupled with the delivery conduit 251 downstream of the three-way valve 50 to measure the temperature T.sub.W of the mixed carrier fluid, and a third temperature sensor 90C is provided coupled with the return conduit 253 to measure the temperature T.sub.C of the cold carrier fluid, preferably upstream of the three-way valve 50.

[0076] Preferably, at least one sensor 90D is positioned in a room 10 that has an average room temperature T.sub.A higher than an average temperature T.sub.AM of the entire building 1—for example, calculated as the average of the room temperatures T.sub.A of all of the rooms 10 of the building 1. Such a room 10 is preferably selected based on a position thereof inside the building 1. For example, the rooms 10 arranged at an intermediate height of the building 1 and having perimeter walls exposed to the south will have a higher average room temperature T.sub.A with respect to the other rooms 10. Possibly, the average temperatures of each room can be detected during an implementation step of the system. Preferably, a plurality of rooms 10—for example, three—with higher average room temperature T.sub.A is selected and a sensor 90D is arranged in each of them.

[0077] Moreover, at least one sensor 90E is positioned in a room 10 that has an average room temperature T.sub.A lower than the average temperature T.sub.AM of the building 1. Also in this case, the room 10 is preferably selected based on a position thereof inside the building 1. For example, the rooms 10 arranged at ground level and having perimeter walls exposed to the north will have a lower average room temperature T.sub.A with respect to the other rooms 10. Possibly, the average temperatures of each room can be detected during an implementation step of the system. Preferably, a plurality of rooms 10—for example, three—with a lower average room temperature T.sub.A is selected and a sensor 90E is arranged in each of them.

[0078] Additionally, there is a temperature sensor 90F to detect the external temperature T.sub.E of the external environment 30. Preferably, the heating system 20 also comprises one or more sensors for acquiring other environmental parameters. For example an irradiation sensor 95 can be associated with the building 1 so as to measure a solar irradiation I to which the building 1 is subjected.

[0079] The control unit 80 comprises a processing module 81—for example, which includes one or more among a microcontroller, a microprocessor, an ASIC, an FPGA—a memory unit 83 and, preferably, one or more input controller modules 85 and 86 an output controller module 87—for example, comprising PID controllers. In general, the control unit 80 can comprise one or more ancillary circuits (not illustrated), like a circuit for generating a synchrony signal (clock), amplifiers for input/output signals, power supply circuitry, etc.

[0080] In the example considered, the processing module 81 is operatively coupled with the memory unit 83, with the controller modules 85 and 86, at least with the sensors 90B, 90C, 90F and 95. Advantageously, the processing module 81 can also be operatively connected to an external electronic entity 100—for example, a server of a company managing the heating system 20—through a suitable data transmission channel 105.

[0081] Moreover, a first input controller module 85 is connected to the temperature sensor 90D that measures a room temperature T.sub.Amax of the room 10 having an average room temperature T.sub.A higher than an average temperature T.sub.AM of the building 1.

[0082] Similarly, a second input controller module 85 is connected to the temperature sensor 90E that measures a room temperature T.sub.Amax of the room 10 having an average room temperature T.sub.A lower than an average temperature T.sub.AM of the building 1.

[0083] If the controllers 85 are not present, the sensors 90D and 90E are operatively coupled with the processing module 81.

[0084] Finally, the output controller module 87 is operatively coupled with the temperature sensor 90A and with the heat generator 23 and with the three-way valve 50.

[0085] With reference to the flow diagram of FIG. 3 the operation of the heating system 20 according to an embodiment of the present invention will now be described.

[0086] In general, the control unit 80 is configured to adjust the operation of the heating system 20 so as to bring and/or keep each room 10 to/at the desired room temperature T.sub.A reducing the consumption and/or the turning on/off cycles of the heat generator 30. For example, the desired room temperature T.sub.A can be set through a thermostat (not illustrated). Additionally or alternatively, one or more default room temperatures T.sub.A can be saved in the memory 83.

[0087] In particular, the control unit 80 acquires the external temperature T.sub.E and the irradiation measurement I from the sensors 90F and 95, respectively, and supplies them in input to a simplified model 1101 of the heating system 20.

[0088] Optionally, the simplified model 1101 can receive in input measurement provided by the other aforementioned sensors and/or information relating to weather forecasts—for example, predicted temperatures and irradiation conditions within a future time period—that the processing module 81 acquires from the external entity 100. Such measurements and information can be used to correct the simplified model or the results provided by it.

[0089] Advantageously, the simplified model 1101 can be defined at the end of an installation step of the heating system 20 and be stored in the memory 83. Additionally or alternatively, the simplified model 1101 can be defined or updated periodically based on functional parameters of the heating system stored in the memory 83 and measurements of the temperatures acquired through the sensors 90A—90C and/or by the thermostat valves 60.

[0090] In a preferred embodiment, the simplified model 1101 can be defined based on a relationship f between the temperature T.sub.W of the mixed fluid and a temperature difference ΔT between the temperature T.sub.W and the temperature T.sub.C of the cold carrier fluid as a function of the external temperature T.sub.E and of the irradiation I measured—and, possibly, other information acquired by other sensors and/or provided by the external entity 100.

[0091] Alternatively, the Applicant has determined that the parameters of the simplified model 1101 can be defined by means of linear regression, or alternatively, by means of classes of non-linear functions like, for example, non-linear ARX, or methods based on spectral analyses and cross-correlation or other methods for frequency analysis.

[0092] Additionally, the Applicant has determined that the simplified model 1101 can be corrected/updated during the operation of the heating system 20, recording in the memory 83 the performed measurements provided by the sensors 90, 95 and using such historical data as input variables, for example using a SARIMAX model to obtain a simplified model 1101 capable of taking into account a cyclical/seasonal nature to which the acquired measurements and, more in general, the thermal progression of the building 1 are subjected.

[0093] The simplified model 1101 created by the control unit 80 makes it possible to estimate a target temperature T.sub.W1 to which to bring the mixed carrier fluid in the delivery conduit 251 downstream of the three-way valve 50. In the embodiment considered, the target temperature T.sub.W1 makes it possible to bring the temperature difference ΔT between the temperature T.sub.W and the temperature T.sub.C of the carrier fluid in the two conduits 251 and 253, towards an optimal value ΔT.sub.OPT which makes it possible to ensure the desired room temperature T.sub.A in one or more rooms 10 minimizing the temperature T.sub.H of the hot carrier fluid and/or minimizing the switching on/off of the heat generator 23. In an embodiment, the simplified model 1101 determines a target temperature T.sub.W1 and allows a sub-optimal value ΔT.sub.SOPT of the temperature difference ΔT to be reached, for example comprised between 75%-95% of the optimal value ΔT.sub.OPT. Preferably, the target temperature T.sub.W1 is a substantially constant value so long as the values of the external temperature T.sub.E and of the irradiation I remain constant or within a predetermined tolerance range.

[0094] In detail, the simplified model 1101 can be configured to determine the target temperature T.sub.W1 identifying an optimal work point on the relationship f between the temperature T.sub.W and the temperature difference ΔT, as a function of the external temperature T.sub.E and the measured irradiation I. For example, the optimal work point can be identified as the point at which an angular coefficient—or a first derivative—of the relationship f changes from a first value, for example a maximum, to a second value, for example a lower value,—i.e., at an ‘elbow’ of the relationship f.

[0095] In parallel to the simplified model 1101, the control unit 80 creates a control procedure 1103 not based on a model that has the purpose of determining a variable target adjustment temperature T.sub.W2 such as to make it possible to reach the optimal value ΔT.sub.OPT and keep it dynamically against changes in the temperatures T.sub.W and T.sub.C of the carrier fluid in the conduits 251 and 253, the measurements of which are provided in input to the control procedure 1103. For example, the control procedure 1103 comprises a procedure selected among perturb and observe, extremum seeking and sliding mode. In a preferred embodiment, the control procedure 1103 provides for implementing an extremum seeking control procedure.

[0096] With particular reference to the flow diagram of FIG. 4, the control procedure 1103 provides for supplying (block 401) a periodically variable adjustment temperature T.sub.W2—for example, in a sinusoidal manner. Such an adjustment temperature T.sub.W2 is used as reference to actuate the three-way valve 50 and/or the heat generator 23—through the respective controllers 86 and 87—as described hereinafter—so as to cause a corresponding perturbation in the temperature T.sub.W of the mixed carrier fluid.

[0097] Subsequently, the control procedure 1103 provides for monitoring (block 403) the temperature T.sub.W and the temperature T.sub.C of the carrier fluid in the two conduits 251 and 253, so as to identify a response of the heating system 20 to the perturbation determined by the adjustment temperature T.sub.W2. In detail, the procedure 1103 verifies (decisional block 405) whether a maximum—or, alternatively, minimum—point corresponding to the optimal value ΔT.sub.OPT has been reached. In the affirmative case (output branch Y of block 405) the adjustment temperature T.sub.W2 allows the optimal value ΔT.sub.OPT to be reached and it is kept unchanged (block 407) until there is a change in the temperatures T.sub.W and T.sub.C of the carrier fluid in the two conduits 251 and 253 that determines a temperature difference ΔT that differs from the optimal value ΔT.sub.OPT—possibly, outside of a tolerance range—for example, due to a change in heat exchange between one or more radiating elements 21 and the respective rooms 10.

[0098] Differently (output branch N of the block 405), the procedure 1103 identifies (decisional block 409) whether the adjustment temperature T.sub.W2 must be increased (output branch Y of block 409) or decreased (output branch N of block 409) to reach the optimal value ΔT.sub.OPT and consequently modifies (at block 411 or at block 413, respectively) the value of the adjustment temperature T.sub.W2 before returning to block 403 to monitor the progression of the temperature measurements T.sub.W and T.sub.C of the carrier fluid in the two conduits 251 and 253 following the selected change.

[0099] Going back to the flow diagram of FIG. 3, the target temperature T.sub.W1 and the adjustment temperature T.sub.W2 are combined with each other to obtain a total temperature T.sub.WT. For example, the temperatures T.sub.W1 and T.sub.W2 are added together (adding node 1105) to obtain the total temperature T.sub.WT.

[0100] Preferably, the control unit 80 is configured to verify that the total temperature T.sub.WT thus obtained does not bring the room temperature T.sub.A of one or more rooms 10 outside of a permitted temperature range. For example, the control unit 80 verifies that the room temperatures T.sub.A are comprised between, or equal to, 18° C. and 22° C.—for example, in accordance with the legal limits, to limit the consumption of the system 20 and/or to limit polluting/greenhouse emissions of the system 20.

[0101] This operation is implemented thanks to the controllers 85 connected to the sensors 90D and 90E. In detail, one or more first controllers 85—one in the example of FIG. 3—monitor the room temperature measurement T.sub.A provided by respective sensors 90D—one visible in the example of FIG. 3—to detect a maximum room temperature T.sub.Amax in one or more of the rooms 10 that have an average room temperature T.sub.A higher than the average T.sub.AM of the building 1. For example, the average temperature T.sub.AM is determined by the processing module 81 based on the measurements provided by one or more sensors and/or thermostats in real time. Additionally or alternatively, one or more average temperatures T.sub.AM can be stored in the memory 83 obtained based on an analysis over time of the room temperatures T.sub.A—carried out during the installation of the system 20 and/or afterwards.

[0102] The first controller 85 implements a procedure 1107—for example, a PID control—to determine a maximum acceptable value T.sub.Wmax of the temperature T.sub.W of the mixed carrier fluid that ensures that the temperature T.sub.Amax is not raised above a higher threshold value—for example, 22° C.

[0103] The acceptable maximum value T.sub.Wmax is compared (block 1109) with the total temperature T.sub.WT, and the lower value of the two is selected.

[0104] Similarly, one or more second controllers 85—one in the example of FIG. 3—monitor the room temperature measurement T.sub.A provided by sensors 90E —one in the example of FIG. 3—to detect a minimum room temperature T.sub.Amin in one or more of the rooms 10 that have an average room temperature T.sub.A lower than an average temperature T.sub.AM of the building 1.

[0105] The second controller 85 implements a procedure 1111—for example, a PID control—to determine a minimum acceptable value T.sub.Wmin of the temperature T.sub.W of the mixed carrier fluid that ensures that the temperature T.sub.Amin is not lowered below a lower threshold value—for example, 18° C.

[0106] The minimum acceptable value T.sub.Wmin is compared (block 1113) with the temperature provided in output by block 1109—i.e., the total temperature T.sub.WT, or the acceptable maximum value T.sub.Wmax—and the greater value of the two is selected.

[0107] In other words, the control unit 80 provides in output block 1113 a reference temperature T.sub.WSP selected among the total temperature T.sub.WT—in particular, the total temperature T.sub.WT—, the acceptable maximum value T.sub.Wmax or the minimum acceptable value T.sub.Wmin.

[0108] The reference temperature T.sub.WF is used to change the temperature difference ΔT between the temperature T.sub.W of the mixed carrier fluid and the temperature T.sub.C of the cold carrier fluid to reach the optimal value ΔT.sub.OPT. For this purpose, the control unit 80 actuates at least one among the heat generator 23 and the three-way valve 50 based on the selected reference temperature T.sub.WF. In particular, the reference temperature T.sub.WF can be used to change the control of the heat generator 23 and/or to change the opening of the three-way valve 50 so as to change the proportion of hot carrier fluid and of cold carrier fluid that are mixed to form the mixed carrier fluid in the delivery conduit 251 downstream of the valve 50.

[0109] In the example considered, the selected reference temperature T.sub.WF is provided in input to the controller 86, which also receives the measurement of the temperature T.sub.W of the mixed carrier fluid. The controller 86 implements a valve adjustment procedure (block 1115) that generates a valve control signal S.sub.V, which determines an open position of the three-way valve 50 based on the reference temperature T.sub.WF and on the current temperature T.sub.W of the mixed carrier fluid (provided by the sensor 90B). The valve control signal S.sub.V is provided to the three-way valve 50 to determine an operating condition—or opening—that adjusts the mixing between cold carrier fluid—at temperature T.sub.C—and the hot carrier fluid—at temperature T.sub.H—so that the temperature T.sub.W of the mixed carrier fluid corresponds to the selected reference temperature T.sub.WF (i.e. T.sub.W=T.sub.WF).

[0110] In this way, the control system 80 is capable of changing the temperature T.sub.W of the mixed carrier fluid in the conduit 253 downstream of the three-way valve 50 quickly, allowing the system 20 to respond quickly to changes in the thermal loads associated with the radiating elements 21.

[0111] The control system 80, in particular the generator controller 87, also implements a temperature adjustment procedure (block 1117) to adjust the temperature T.sub.H of the hot carrier fluid output from the heat generator 23 based on the operating condition of the three-way valve 50. In particular, the procedure 1117 receives in input the valve control signal S.sub.V and determines a hot reference temperature value T.sub.HSP to which the temperature T.sub.H of the hot carrier fluid can be brought. Advantageously, the procedure 1117 is configured for identifying the hot reference temperature value T.sub.HSP that allows the consumption of the heat generator 23 to be reduced.

[0112] The hot reference temperature value T.sub.HSP is provided in input to a generator adjustment procedure (block 1119)—for example, based on hysteresis—implemented by the generator controller 87. The generator adjustment procedure 1119 also receives in input the measurement of the temperature T.sub.H of the hot carrier fluid and is configured to provide in output a generator control signal S.sub.G suitable for bringing the temperature T.sub.H of the carrier fluid output to the hot reference temperature value T.sub.HSP.

[0113] In the preferred embodiment, the hot reference temperature value T.sub.HSP is determined so as to allow the three-way valve 50 to be brought back into a desired operating condition. For example, the Applicant has identified a desired operating condition for the three-way valve 50 such that the carrier fluid in the delivery conduit 251 downstream thereof is given by a mixture comprising 80% hot carrier fluid and 20% cold carrier fluid. Analyses by the Applicant have highlighted that such an operating condition of the three-way valve 50 makes it possible to efficiently change the temperature T.sub.W of the mixed carrier fluid over a wide dynamic and, at the same time, ensures efficient operation of the heat generator 23.

[0114] An example combined adjustment of the temperature T.sub.H of the hot carrier fluid and of the operating condition of the three-way valve 50, is now described in reference to the graphs of FIG. 5.

[0115] Initially, the valve control signal S.sub.V oscillates around a value S.sub.V0 corresponding to the desired operating condition of the three-way valve 50—as can be seen in FIG. 5.

[0116] Consequently, the temperature T.sub.W of the mixed carrier fluid reaches the neighbourhood of a first target value T.sub.WSP0. In these conditions, the temperature difference ΔT approaches a first optimum value ΔT.sub.OPT0—oscillating in an extremely contained manner around such a value, as can be seen in FIG. 5.

[0117] When, at a time to, there is a change to a second target value T.sub.WSP1—for example, lower than the first target value T.sub.WSP0 the valve adjustment procedure 1115 changes the valve control signal S.sub.V—almost instantly—so as to change the mixing proportion of the hot carrier fluid and of the cold carrier fluid, so as to bring the temperature T.sub.W of the mixed carrier fluid substantially to the second target value T.sub.WSP0. In the illustrated example, the valve control signal S.sub.V actuates the three-way valve 50 to substantially increase the proportion of cold carrier fluid and reduce the proportion of hot carrier fluid, thus reducing the value of the temperature T.sub.W of the mixed carrier fluid. In this way, the temperature difference ΔT quickly reaches a second optimal value ΔT.sub.OPT1.

[0118] Substantially in parallel to the change of the operating condition of the three-way valve 50, the temperature adjustment procedure 1117 implemented by the generator controller 87 dynamically changes the hot temperature reference value T.sub.HSP. Based on the hot temperature reference value T.sub.HSP the generator adjustment procedure 1119 adjusts the operation of the heat generator 23 so as to obtain the hot carrier fluid substantially at a second temperature value T.sub.H1—lower than the first temperature value T.sub.H0 in the example considered—that makes it possible to bring the three-way valve 50 to operate in the desired operating condition.

[0119] In particular, the change of the temperature T.sub.H of the hot carrier fluid consequently changes the temperature T.sub.W of the mixed carrier fluid downstream of the three-way valve 50. The valve controller 86 detects this change in temperature T.sub.W of the mixed carrier fluid and adjusts the valve control signal S.sub.V as a consequence (increasing ramp in FIG. 5) until it goes back to oscillating around the value S.sub.V0 corresponding to the desired operating condition.

[0120] Consequently, at a second time t1 the heat generator 23 provides the hot carrier fluid at the second temperature value T.sub.H1, thus reducing the consumption of the heat generator 23, whereas the three-way valve 50 operates in the desired operating condition, obtaining a particularly efficient operating condition of the heating system 20.

[0121] The flow diagram of FIG. 6 illustrates the operation of a heating system 20 according to an alternative embodiment of the present invention.

[0122] In particular, the heating system 20 does not provide for the controllers 85. In this case, the operation differs from what is described above in that the minimum room temperature T.sub.Amin and the maximum room temperature T.sub.Amax are acquired directly by the controller module 81 of the control unit 80 and are provided in input to a modified version of the control procedure 1103′. In detail, the modified control procedure 1103′ provides for determining a perturbation to be applied, i.e. an adjustment temperature TW.sub.2, such as to avoid a room temperature T.sub.A lower than the minimum room temperature T.sub.Amin or higher than the maximum room temperature T.sub.Amax being reached in one or more of the rooms 10.

[0123] The invention thus conceived can undergo numerous modifications and variants all of which are encompassed by the present invention as results from the attached claims.

[0124] For example, the heating system 20 can comprise other components like a hydraulic separator or decoupler arranged upstream of the three-way valve, one or more safety and/or venting valves to avoid over/under-pressures in the distribution network, filtering modules, decalcifiers, sludge remover, etc.

[0125] In an embodiment, many three-way valves can be arranged in the distribution network 25. For example, a three-way valve can be provided for each radiating element or group of radiating elements 21—like, a group of radiating elements arranged in a same room 10 of the building. In this case, the control unit 80 is configured to control the mixing of the carrier fluid in input and in output to/from each radiating element 21, or group of radiating elements 21, in accordance with corresponding room temperatures T.sub.A.

[0126] Moreover, nothing prevents from processing the inputs provided to the control procedure 1103 with non-linear techniques—like, for example, the addition of hysteresis—or the use of on-line heuristics for data conditioning, like—for example—normalization, innovation threshold, max innovation, terminal constraint, etc. In this way it is possible to increase the reliability of the system in determining and following the optimal adjustment of the heating system 20.

[0127] Advantageously, the controllers 85, 86 and 87 can also implement optimisation methods and/or algorithms of its operating parameters, such as the P I D parameters. For example, the controllers can implement lambda-tuning methods or extremum seeking controls dedicated to seeking the optimum adjustment or tuning.

[0128] Furthermore, one or more of the controllers 85, 86 and 87 can be omitted, formed by one or more distributed modules or they can be implemented together with the processing module 81 in a single integrated electronic unit. Additionally, the operations of the control unit 70 can be implemented by carrying out instructions belonging to a single software block, possibly comprising a model predictive control. Finally, all of the details can be replaced by other technically equivalent elements.

[0129] In conclusion, the materials used, as well as the contingent shapes and sizes, can be whatever according to the specific implementation requirements without for this reason departing from the scope of protection of the following claims.