WO2025219809A1 - Method for regulating start-up of a heating system - Google Patents

Abstract

A method for regulating start-up involves the use of electronic flowmeters, electronically controllable regulator valves and a CPU-based control system for automating the regulation of start-up of a heating system with a circuit inside which there flows a vector fluid, supplied by pressurised vector fluid source (P) to a delivery header (C1) as far as a return header (C2), connected to a supply (P1) of the pressurised vector fluid source. Multiple user branch-lines (L1, L2, Li, Ln) are arranged hydraulically in parallel between the delivery header (C1) and the return header (C2), each being provided with a respective radiating user appliance (U1, U2, Ui, Un). The CPU controls variation of the opening of a DPCV regulator valve so as to reduce gradually the total flow (Q) of the fluid at the inlet or outlet of the delivery header or the return header, monitoring at the same time the differential pressure (Dp) between the delivery header (C1) and the return header (C2) by means of a differential pressure detection sensor. The CPU also monitors the flowrate (Qi) through each user branch-line by means of the electronic flowmeters. When a flowrate (Qi) in a first user branch-line is detected as being equal to the design flowrate (Q_des_i) for that user branch-line, the value (Dp(t0)) of the differential pressure (Dp) detected between the delivery header (C1) and the return header (C2) is stored and set as a reference differential pressure (Dp_set).

Description

METHOD FOR REGULATING START-UP OF A HEATING SYSTEM

DESCRIPTION

The present invention relates to a method for regulating the start-up of a heating system and a corresponding heating system configured to be started by means of the regulating method.

In the technical sector relating to the construction of fluid distribution networks it is known that there exists the need to provide and regulate thermo-sanitary or heating systems of the underground radiant panel type.

In the hydro-thermo-sanitary technical sector during the last few years attention has been increasingly focused on the environments in which one lives and the increasingly more demanding requirements with regard to energy consumption. In addition to these requirements there are also regulatory aspects, the most important one of which is the energy certification of buildings, which has become an important factor in the economic valuation of a property. The need to ensure the efficient use of energy in buildings has promoted the use of radiant panel systems which offer significant advantages from the point of view of both comfort and energy consumption.

In this context a heating system comprising a circuit for circulating a vector fluid is known, said circuit comprising: a pressurised vector fluid source which supplies a delivery header, a return header, which is connected to a supply of the pressurised vector fluid source, and a plurality of branch-lines (also referred to by the term “loop”) which each include a respective radiating user appliance, generally in the form of a tube coil to be positioned underground.

The delivery header comprises a plurality of branch-off ducts, each connected to a distribution duct of a respective branch-line so as to convey the vector fluid to the respective radiating user appliance, and the return header comprises a plurality of branch-off ducts, each connected to a return branch-line of a respective branch-line for the return flow of the vector fluid from the respective radiating user appliance to the return header.

Therefore the circuit comprises a plurality of user branch-lines arranged hydraulically in parallel between the delivery header and the return header. The radiating user appliance constitutes the “load” of the respective hydraulic branch-line. In this context, it is known that it is important for each single branch-line or loop to be crossed by the correct vector fluid flowrate so that the fluid flowrate which passes through the radiating user appliance is adapted to the heating requirements of the respective room.

When a hydraulic system comprising radiant coils is designed, the design flowrate values for each single user branch-line are therefore indicated in order to allow the correct balancing of the entire hydraulic circuit.

A known solution for managing these systems involves measuring the flowrate in each branch-line of the circuit by means of flowrate measuring devices (flowmeters) arranged in one of the two headers (generally the delivery header) at the point where the branch-off duct branches off from the respective circuit branch-line, and regulating or intercepting the flow in the branch-line itself by means of a regulator valve arranged on the other header (generally the return header) at the point where the respective return branch-off duct is located.

Another solution for regulating or intercepting the flow in the user branch-line of the circuit can be obtained by using flowmeters which, in addition to showing the value of the flowrate in a circuit branch-line, also allow the flowrate to be regulated or the fluid to be intercepted.

A particularly complex stage in the installation of heating circuits of the type described is that of the initial start-up of the system.

At present, the start-up process is often complicated and uncertain owing to the need to regulate manually the fluid flow through the single user appliances of the system, in order to obtain the predefined design flowrates.

The start-up is generally obtained by manual regulation of the flowrate of each user branch-line by means of an iterative process in which, by adjusting the flowmeters and/or the regulator valves, the design flowrate is set one branchline at a time.

The regulation of one branch-line, however, results in an imbalance in all of the other user branch-lines, so that the process requires numerous repetitions of the manual regulation operation until the circuit is balanced again, with all the branch-lines regulated to provide at least the set design flowrate.

The manual approach is complex, requiring a lot of time and labour, as well as being uncertain in that it is greatly dependent on the experience and capacity of the individual installation engineer. The growing automation and number of regulations governing hydro-thermo- sanitary systems also means that the current methods for regulating the start-up of the heating systems of the type described are inadequate.

Examples of a method according to the preamble of Claim 1 are described in EP 2,376,841.

The technical problem which is posed therefore is that of simplifying and optimizing the start-up of hydrothermal systems, thereby overcoming the problems of complexity and uncertainty associated with the manual methods which are currently used.

In connection with this problem it is also required that the method for regulating start-up should be substantially automated, requiring the least possible intervention on the part of the installation engineer.

A further desirable aspect is that the method and the system should be easy and inexpensive to realize.

These technical problems are solved according to the present invention by a method for regulating start-up of a heating system according to Claim 1 and by a heating system according to Claim 10.

The method involves the use of electronic flowmeters, electronically controllable regulator valves and a control system based on an electronic processing and control unit for automating the start-up process.

The electronic unit controls variation of the opening of a DPCV regulator valve so as to reduce gradually the total flow of the fluid at the inlet or outlet of the delivery header or the return header, monitoring at the same time the differential pressure between the headers by means of a differential pressure detection sensor. The processing unit also monitors the flowrate passing through each user branch-line by means of the electronic flowmeters. When a flowrate in a first user branch-line is detected as being equal to a design flowrate for that user branch-line, the differential pressure value detected between the delivery header and the return header is stored and set as a reference differential pressure.

Further preferred embodiments are described in the attached dependent claims. Further details and technical advantages may be obtained from the following description of a non-limiting example of embodiment of the invention, provided with reference to the accompanying drawings, in which: Figure 1 : shows a schematic view of a structure of a coil heating system, with a plurality of user branch-lines connected in parallel to a delivery header and to a return header;

Figure 2: shows a schematic illustration of the hydraulic circuit of the system according to Figure 1 , during a first start-up regulating step;

Figure 3: shows a flow diagram of an example of implementation of a first step of the method for regulating start-up according to the present invention;

Figure 4: shows a flow diagram of an example of implementation of a second step of the method for regulating start-up according to the present invention.

With reference to Fig. 1 , one aspect of the present invention relates to a method for regulating start-up of a heating system 1 comprising a circuit for circulating a vector fluid. The preferred example of a circuit shown comprises a pressurised vector fluid source P, conventional per se and comprising for example a vector fluid delivery pump. The pump P is supplied by a supply P1 of the pressurised vector fluid source, such as a suitable tank per se conventional and not described in detail.

The source P supplies the pressurised vector fluid to a delivery header C1 which comprises a plurality of branch-off ducts d 1 , d 2, d n, each connected to a distribution duct of a respective user branch-line L1 , L2, Ln for conveying the vector fluid to a respective radiating user appliance U1 , U2, for example a coil tube for underground heating in a designated room or space.

Each radiating user appliance U1 , U2, Un is in turn connected by means of a return duct of the respective user branch-line L1 , L2, Ln to a return header C2, in turn connected to the supply P1 of the pressurised vector fluid source P.

In particular, the return header comprises a plurality of branch-off ducts c21 , c22, c2n each connected to a return duct of a user branch-line for return of the vector fluid from the respective radiating user appliance U1 , U2, Un to the return header.

Therefore, the circuit comprises a plurality of user branch-lines L1 , L2, Ln arranged hydraulically in parallel between the delivery header C1 and the return header C2, each user branch-line comprising a respective radiating user appliance U1 , U2, Un. This arrangement is conventional per se.

Multiple electronic flowmeters f1 , f2, fn are coupled to one of the delivery header and the return header, preferably the delivery header C1 , as shown in Fig. 1 . Each electronic flowmeter f1 , f2, fn is arranged opposite a respective branch-off duct c11 , c12, d n of the header C1 so as to provide an electronic signal indicating a vector fluid flowrate Q1 , Q2, Qn on the respective branch-line L1 , L2, Ln.

A plurality of electronic regulator valves A1 , A2, An are coupled to the other header, each regulator valve being designed to regulate the flowrate through a respective user branch-line L1 , L2, Ln.

Each electronic regulator valve is arranged opposite a respective branch-off duct of the header and can be controlled electronically so as to regulate the incoming or outgoing flow through it, therefore regulating the vector fluid flowrate Q1 , Q2, Qn which crosses the respective user branch-line.

An electronic DPCV valve AO is arranged at the outlet of the return header, between the latter and the supply P1 of the pump P.

The DPCV valve can be electronically controlled to regulate the total flowrate Q which crosses the header and which therefore circulates between the delivery header, the user branch-lines L1 , L2, Ln and the return header, depending on a differential pressure Dp between the delivery header and the return header.

An electronic sensor for detecting a differential pressure Dp between the delivery header and the return header is arranged and configured to detect a differential pressure between the delivery and return headers and to emit a corresponding electronic signal indicating said differential pressure Dp.

A central processing unit (CPU) is designed to control the heating system 1 .

The CPU may be a suitable electronic control unit comprising hardware, firmware, memories and input and output interfaces connected to said electronic flowmeters f1 , f2, fn, to said DPCV regulator valve AO, to said differential pressure detection sensor and to said regulator valves A1 , A2, An for receiving electronic detection signals and emitting electronic control signals.

The CPU may also comprise suitable telecommunication means for connection externally, for example of the Bluetooth type, Ethernet type, etc.

In the example shown, it is envisaged that the CPU may communicate with a portable electronic user device app, such as a smartphone or a tablet provided with a dedicated application, for providing the installation engineer and/or the final user with a user interface.

It will be clear to the person skilled in the art that this is a preferred configuration and that other configurations are possible; for example, it is possible to envisage also a user interface directly on the CPU or by means of a a web server which can be accessed via an Internet connection.

With this configuration and with further reference to Figures 2-4, a preferred example of embodiment of a method for regulating start-up of the present invention may comprise the following steps: supplying pressurised fluid to said delivery header C1 from said fluid source P; detecting the vector fluid flowrate Q1 , Q2, Qn in each user branch-line L1 , L2, Ln by means of the respective electronic flowmeter f1 , f2, fn and transmitting the signal to the CPU which detects a flowrate measurement Qi of the fluid flow in the user branch-line Li; regulating, by means of the processing unit, the opening of said regulating DPCV regulator valve AO and of said user branch-line regulator valves A1 , A2, An so as to determine a flowrate Qi in each user branch-line Li of the circuit greater than a respective design flowrate Q_des_i predefined for the user branch-line and stored in the processing unit.

In this initial part of the method, an example of which is schematically shown in Figures 2 and 3, the hydraulic circuit is supplied with pressurised fluid and the CPU reads 103 the measurement data of the flowrate Qi of each user branchline Li and checks 104 that the total fluid flowrate Q is sufficient to meet the design flowrate requirements Q_des_i for each branch-line Li.

In preferred embodiments, as schematically indicated by means of the reference number 102 in Figures 2, 3, all the modulating actuators of the regulator valves A0, A1 , A2 may be regulated in the fully open position corresponding to the maximum possible fluid flowrate which can be regulated through the respective valve.

If the electronic flowmeters should have a manual system for regulating the opening of the corresponding branch-off duct d 1 , c12, d n, this is preferably also set to the maximum possible flowrate. Advantageously, the method according to the present invention allows flowmeters which already completely “open” to be provided and installed, no further manual operation thereof being subsequently required

If the overall flowrate should be insufficient, the CPU may emit a command message 104 indicating an “insufficient flowrate” which must be corrected by means of an increase in the performance of the pump P. Should the control of the pump P be assigned to the CPU, the latter may directly perform a suitable increase of the overall flowrate Q.

The design flowrate values Q_des_i may be introduced by the operator via the respective user app interface, as schematically indicated by the reference number 10 in Fig. 3. These values could also be preset in the memory of the CPU or automatically set, for example by means of a connection to a corresponding remote server.

In some embodiments, following the start-up of the pump P, the processing unit may read the flowrate data from the flowmeters f1 , f2, fn in order to check beforehand that the flowrate Qi is greater than zero on each branch-line Li. If the outcome of the check is negative, the CPU may emit a warning signal which allows the operator to check in loco whether all the regulator valves and/or flowmeters are correctly open and/or whether the pump is operating correctly. This preliminary check may also be omitted, it being in any case implicit in the subsequent check that there is a sufficient vector fluid flow on all the branchlines Li compared to the set design flowrates Q_des_i.

Once it has been checked that there is a sufficient total flowrate Q circulating in the circuit, the CPU obtains a reference differential pressure Dp set for regulating the system, by means of the DPCV regulator valve AO, for example as follows: varying 106, by means of the processing unit, opening of the DPCV regulator valve A0 so as to reduce gradually the total flowrate Q of the fluid flow at the inlet or outlet of the delivery header C1 or the return header C2, monitoring 107 at the same time: o the differential pressure between the headers by means of the detection sensor and the processing unit, and o the flowrate Qi through each user branch-line by means of the electronic flowmeters and the processing unit, until it is detected (Fig. 3, 108) that there is a flowrate Qi* on a first user branchline Li* which is equal to the design flowrate Q_des_i* for that user branch-line; detecting and storing (Fig. 3, 109) the value of the differential pressure Dp) between the headers detected when the design flowrate is reached on the said first branch Qi* and setting thereof (Fig. 3, 1110) as the reference differential pressure by the processing unit Dp set by the processing unit.

Therefore, for example, the CPU may obtain from the signal measuring the flowrate Qi*(t) on each first user branch-line Li* which is hydraulically satisfactory a time instant tO in which Qi*(tO) = Q_des_i* and read the corresponding value of the differential pressure signal Dp(t) at said time instant tO. This differential pressure value Dp(10) is then stored in a memory unit of the CPU and set as the reference differential pressure value Dp set.

As schematically shown in Fig. 4, once the reference differential pressure Dp set has been set, the method proceeds with the following further steps: for each user branch-line Li other than the first user branch-line Li* (Fig.

4, 111 ): the processing unit reads 112 the flowrate data Qi for the flow on the user branch-line Li and regulates, by means of the respective electronic regulator valve Ai, the flowrate Qi of the vector fluid flow across the user branchline until the flowrate Qi on the user branch-line Li is equal to the design flowrate Q desJ for that user branch-line Li (Fig. 4: 113,114),

- at the same time the CPU monitors (Fig. 4: 115, 115a) and regulates (Fig. 4, 116) the differential pressure Dp between the headers by means of the detection sensors and the DPCV regulator valve AO so that the differential pressure Dp is maintained or restored in each case to the reference value by means of the DPVC regulator valve.

Preferably, this step of regulating the user branch-lines Li other than the first user branch-line Li* is performed by regulating one user branch-line at a time and restoring every time the reference differential pressure Dp set by means of the DPVC valve AO. However, it is also possible to regulate several branch-lines simultaneously or even all the branch-lines Li simultaneously by means of the DPVC valve AO so as keep the Dp at the reference value Dp set.

Once all the user branch-lines Li are crossed by a vector fluid flowrate Qi which corresponds to the design flowrate Q_des_i and the differential pressure is at the reference value Dp_set, regulation of the start-up is complete (Fig. 4, 117).

The CPU may at this point switch to a mode for normal management of the system, where the flowrate of each user branch-line is regulated depending on a temperature value desired for the respective designated room or space (set for example via a local control unit or via a user interface) and the temperature value detected by a respective thermostat installed in that room. During normal operation, the CPU will also monitor the differential pressure Dp between the headers, intervening by means of the DPCV regulator valve AO so as to keep said pressure at the reference value Dp set obtained and stored during regulation of the start-up.

Below a number of preferred embodiments of various elements of the method and the system according to the present invention will be described.

Electronic flowmeter

There exist on the market electronic devices for measuring the flowrate of a flow, which are able to generate an electronic signal proportional to the flowrate of a flow in a branch-off duct of a header.

A hybrid electronic flowrate measuring device which is particularly preferred for use as a flowmeter in a circuit according to the present invention is described in Italian patent application 102023000027336 filed in the name of the same present Applicant, the contents of which are cited here by reference.

In short, the preferred electronic flowmeter for measuring the flowrate in the branch-off duct of the header may comprise a connection-piece for coupling to the header, a duct transverse to the header and coaxial, during use, with the branch-off duct, a stem movable coaxially in the transverse duct, which has a bottom end part which interacts with the fluid inside the branch-off duct, so as to move the stem axially upon variation in the flowrate through the branch-off duct and a magnetic element integral with the stem. A sensor sensitive to the magnetic field is arranged to detect the position of the magnetic element and emit an electric signal which varies upon variation in the position of the magnetic element and therefore indicates a measurement of the flowrate through the branch-off duct. Preferably, the flowmeter is hybrid and also comprises a top end part of the stem which has a visible indicator element and provides a visual indication of a measurement of the flowrate, Moreover, according to the conventional art, a mechanical system for manually adjusting opening/closing of the branch-off duct may be present, but is not necessary in the regulating method and system according to the present invention. If present, said mechanical system is arranged in the position for total opening of the branch-off duct, it not being required for regulating start-up of the heating system. As regards the magnetic sensor, it may be preferably a Hall effect sensor, particularly advantageous since it is able to detect the presence, the intensity and the polarity of the magnetic field due to the magnetic element and emit a variable output signal depending on these parameters.

The method according to the present invention may in any case be implemented using any electronic flowmeter able to generate a measurement signal for the fluid flowrate through the user branch-line.

Reading of the flowrate data

In general terms, the processing unit may be configured to acquire from each flowmeter f1 ,..fn an electronic signal converted with a certain transfer characteristic from a detected value which is associated with the flowrate of the vector fluid passing through the respective user branch-line, for example the movement of an end part of a stem, moved by the fluid flow entering or exiting the respective branch-off duct of the delivery or return header. The electronic signal acquired therefore represents the fluid flowrate through the user branchline and may be processed by the CPU in order to obtain a signal Qi(t) providing a measurement of the flowrate on the respective user branch-line Li.

Irrespective as to the specific configuration of the flowmeters f1 , f2 and the detected value which is converted into the signal indicating the flowrate Qi on the respective user branch-line Li, preferably the processing unit acquires and obtains a signal for the flowrate of the user branch-line in a substantially continuous manner, i.e. with an acquisition and sampling frequency which is sufficiently high in relation to the variation of the fluid flow in the circuit and such as to allow the completion of the start-up operations in a reasonable amount of time, for example about a few minutes.

The choice of the specific detection modes, of a suitable sampling frequency and of the appropriate acquisition and digital conversion techniques for generating and managing the signal indicating the user branch-line flowrate and/or the measurement signal for the said flowrate come within the normal competence of the design engineer.

User branch-line regulator valve

Electronic valves for regulating the flowrate of a fluid flow at the inlet or outlet of a branch-off duct of a header exist on the market.

A preferred regulator valve for use in a circuit according to the present invention is described in Italian patent application 10202400002136 filed in the name of the same present Applicant, the contents of which are cited here by reference.

Such a preferred regulator valve comprises a valve insert which comprises: a connection piece for coupling to a valve body, defining a vertical duct; a stem movable coaxially inside the vertical duct between a top end-of-travel position and bottom end-of-travel position, the stem having a bottom end provided with an obturator designed to vary the opening and if necessary close the branch-off duct of the header.

The regulator valve further comprises an actuator for actuating the stem, comprising: an actuator body and an output element operatively coupled to the stem of the valve insert in order to adjust a position of the obturator of the stem of the valve insert along the vertical axis of displacement. The stem is preferably freely displaceable inside the vertical duct of the connection-piece, there not being present elastic or resilient means acting on the stem.

The output element is movable with respect to the actuator body and the actuating actuator further comprises an actuating unit designed to move in a controlled manner the output element with respect to the actuator body so as to move the stem along the vertical axis of displacement in order to adjust the position of the obturator of the stem of the valve insert along the vertical axis of displacement. In preferred embodiments, the actuating unit comprises an electric drive with a driven shaft coupled to the output element so as to move it displaceably along a vertical axis parallel to the axis of the stem of the valve insert.

A preferred electronic regulator valve for use in the system according to the invention therefore comprises an actuator which includes a modulating actuating unit, for example an electric drive, which is able to adjust the position of the obturator along the whole stroke of the stem.

Owing to the fact that the stem of the valve insert is freely displaceable in the vertical direction with respect to the connection-piece, positioning the obturator in a desired vertical position by means of the actuator requires a minimum amount of force, since it is not required to overcome the action of any resilient or elastic means acting on the stem. The employment of modulating actuators, which use energy only when they are operated to move the stem, allow energy savings compared to the common electrothermal ON/OFF actuators which must be continuously powered in order to be able to keep the valve open.

Preferably, the regulator valves A1 , A2 of An each user branch-line are controlled by the CPU with a PID-type control based on a respective flowrate signal Qi detected on the user branch-line Li.

DPCV valve

A preferred two-way DPCV regulator valve for regulating an input or output flow into/from a header for use in a circuit according to the present invention is described in Italian patent application IT 102024000002136 filed in the name of the same present Applicant, the contents of which are cited here by reference.

As described above in connection with the regulator valves A1 , A2, An, such a preferred DPCV regulator valve may comprise: a valve insert, which comprises a connection-piece for coupling to a valve body; a valve body to which the connection-piece is coupled; and an actuator for actuating the stem, which includes a modulating actuating unit, for example an electric drive, which may adjust the position of the obturator of the valve insert along the whole stroke of the stem. The valve body has preferably a longitudinal upstream duct with an upstream mouth, a longitudinal downstream duct with a downstream mouth, a partition which separates the upstream duct from the downstream duct, and a chamber in communication with the upstream duct and with the longitudinal downstream duct, wherein the obturator of the valve insert is arranged in the chamber and configured to regulate or close off the fluid communication between the upstream duct and the downstream duct of the valve body. Therefore the delivery header may be connected to the downstream mouth or the return header may be connected top the upstream mouth.

There exist other commercially available electronic DPCV valves which may be used as an alternative to the preferred valve described.

On the basis of the teachings provided here, it will be within the competence of the design engineer to configure suitable methods for acquiring, sampling, converting and digitalizing the signal Dp(t) for the differential pressure Dp between the headers, as well as a suitable logic for generating the control signal for controlling the DPCV regulator valve A0 based on the differential pressure detected.

Preferably, the DPCV regulator valve A0 for regulating the total flowrate in the circuit is controlled by the CPU with a PID-type control based on the signal Dp(t) for the differential pressure signal Dp detected between the two headers, i.e. delivery header C1 and return header C2.

For all the regulating operations indicated above it is understood that, in the processing unit and/or in the different installed devices, there may be provided suitable tolerance ranges within which two values or signals are considered to correspond for actuation of the method steps described above.

Advantageously, the method according to the invention allows the processing unit to obtain easily and independently a reference value Dp set for the differential pressure between the delivery header and return header, which is used by the processing unit for regulating start-up of the user branch-lines, but also for the subsequent normal operation of the heating system. The reference value Dp set obtained during start-up regulation is in fact able to guarantee a total flowrate Q which is sufficient to satisfy the flowrate requirements of the hydraulic branch-line Li* which is most negatively affected, i.e. which has the highest hydraulic resistance.

It is therefore clear how with the start-up method according to the present invention it is possible to provide a heating system which may be started up quickly and precisely in a completely autonomous and automated manner following installation.

The start-up may also be performed by non-specialized personnel since, once the design flowrates have been inserted, the main regulating operations are delegated to the processing unit.

In addition, the success of the start-up regulation is no longer dependent on the skill of the installation engineer.

Claims

1) Method for regulating start-up of a heating system comprising a circuit for circulating a vector fluid, wherein the circuit comprises: a delivery header (C1), supplied by a source (P) for supplying a pressurised vector fluid; a return header (C2), connected to a supply (P1 ) of the pressurised vector fluid source; and a plurality of user branch-lines (L1 , L2, Li, Ln) arranged hydraulically in parallel between the delivery header (C1 ) and the return header (C2); wherein each user branch-line (L1 , L2, Li, Ln) includes a respective radiating user appliance (U1 , U2, Ui, Un); a plurality of electronic flowmeters (f1 , f2, fn) coupled to one of the delivery header and the return header, each electronic flowmeter being arranged so as to generate an electronic signal indicating a vector fluid flowrate through a respective one of the user branch-lines; a plurality of user branch-line electronic regulator valves (A1 , A2, An), coupled to the other one of the delivery header (C1 ) and the return header (C2), each regulator valve (A1 , A2, An) being arranged and electronically controllable to regulate the flowrate of the vector fluid which circulates through the respective user branch-line; an electronic DPCV regulator valve (AO), arranged at the inlet of the delivery header and at the outlet of the return header and electronically controllable to regulate a total flowrate through the header depending on a differential pressure between the delivery header and the return header; an electronic differential pressure detection sensor, arranged and configured to detect a differential pressure (Dp) between the delivery header (C1 ) and the return header (C2) and to emit an electronic differential pressure signal; a central processing unit (CPU) which is connected to said electronic flowmeters (f1 , f2, fn), to said DPCV regulator valve (AO), to said differential pressure detection sensor and to said regulator valves (A1 , A2, An) and is configured to receive electronic detection signals and to emit electronic control signals; the method comprising the following steps: - supplying pressurised vector fluid to said delivery header (C1 );

- detecting a vector fluid flowrate (Qi) in each user branch-line (Li), by means of the respective electronic flowmeter (f1 , f2, fn) which transmits a respective signal to the processing unit (CPU) which obtains a measurement of the fluid flowrate in the branch-line; and characterized in that it comprises the further steps of: regulating, by means of the processing unit, opening of said DPCV regulator valve (AO) and of said user branch-line regulator valves (A1 , A2, An) so as to determine a flowrate (Q1 , Q2, Qi, Qn) in each user branch-line of the circuit greater than a respective design flowrate (Q_des_i) predefined for the user branch-line and stored in the processing unit;

- varying, by means of the processing unit, the opening of the DPCV regulator valve so as to gradually reduce the total flow (Q) of vector fluid at the inlet or outlet of the delivery or return header, while at the same time monitoring: o the differential pressure (Dp) between the delivery header (C1 ) and the return header (C2), by means of the differential pressure detection sensor and the processing unit, and o the flowrate (Qi) through each user branch-line, by means of the electronic flowmeters and the processing unit, until a flowrate (Qi) in a first user branch-line is detected as being equal to the design flowrate (Q_des_i) for that user branch-line;

- storing the value (Dp(tO)) of the differential pressure (Dp) between the delivery header (C1 ) and the return header (C2) detected when the design flowrate (Q_des_i*) in said first branch-line (Li*) is reached and setting thereof as a reference differential pressure (Dp set) by the processing unit;

- for each user branch-line (Li) other than the first user branch-line (Li*): regulating, by means of the processing unit (CPU) and the respective electronic regulator valve (A1 , A2, An), the flowrate of the vector fluid through the user branch-line until the flowrate (Qi) in the user branch-line (Li) is equal to the design flowrate (Q_des_i) for that user branch-line, while monitoring and regulating the differential pressure (Dp) between the headers by means of the detection sensor, the DPCV regulator valve and the processing unit, such that each time the differential pressure is maintained or restored to the reference value (Dp set).

2) Regulating method according to Claim 1 , wherein the delivery header (C1 ) comprises a plurality of branch-off ducts (d 1 , d 2, d n) each connected to a distribution duct of a respective user branch-line (L1 , L2, Li, Ln) so as to convey the vector fluid to the respective radiating user appliance, and the return header (C2) comprises a plurality of branch-off ducts (c21 , c22, c2n), each connected to a return duct of a respective user branch-line (L1 , L2, Ln) for the return flow of the vector fluid from the respective radiating user appliance to the return header; wherein each user branch-line electronic regulator valve (A1 , A2, An) is arranged and can be electronically controlled to regulate the incoming or outgoing flow through a respective branch-off duct and therefore the flowrate passing through the user branch-line.

3) Start-up regulating method according to the preceding claim, wherein each electronic flowmeter is arranged along a branch-off duct of the said delivery header or return header so that a movable part of the flowmeter which interacts with the vector fluid flow in the branch-off duct moves with a variation in the flowrate through the branch-off duct.

4) Method according to one of the preceding claims, wherein, for regulating the vector fluid flowrate in the user branch-lines (Li) other than the first user branch-line (Li*), the processing unit (CPU) regulates the flowrate (Qi) of one user branch-line at a time by means of the respective electronic regulator valve and each time restores the differential pressure to the reference value (Dp set), regulating the overall flowrate (Q) by means of the DPCV regulator valve (AO).

5) Start-up regulating method according to one of the preceding claims, wherein the processing unit is configured to control each of the user branch-line regulator valves (A1 , A2, An) by means of a PID control system, based on a respective flowrate signal (Qi) detected on the user branch-line (Li).

6) Start-up regulating method according to one of the preceding claims, wherein the processing unit is configured to control the DPCV regulator valve (AO) for regulating the total flowrate (Q) by means of a PID control system, based on a differential pressure signal indicating the differential pressure Y1 detected between the delivery header (C1 ) and the return header (C2).

7) Start-up regulating method according to one of the preceding claims, wherein, in order to determine a flowrate (Qi) in each user branch-line of the hydraulic circuit greater than the respective design flowrate (Q_des_i) predefined for the user branch-line, the processing unit (CPU) is configured to regulate said DPCV regulator valve (AO) and said user branch-line regulator valves (A1 , A2, An) to a respective fully open position and to check that the flowrate (Qi) in each user branch-line is greater than the design flowrate (Q_des_i) predefined for the user branch-line by means of the user branch-line flowrate measurement signals.

8) Start-up regulating method according to the preceding claim, wherein, if the processing unit establishes that the flowrate measured on a user branch-line is less than the design flowrate for that user branch-line, it generates a warning signal indicating that the total flowrate is insufficient and/or increases the total flowrate supplied from the pressurised fluid source (P) to the delivery header (C1 ).

9) Start-up regulating method according to one of the preceding claims, wherein the electronic processing unit (CPU) Is coupled to a user interface (app), preferably to an app which can be run on a portable device connected to the electronic processing unit, the user interface being configured to acquire said predefined values of the design flowrate (Q_des_i) of each user branch-line and to forward them to the processing unit for storage thereof.

10) Heating system comprising a circuit (1 ) for circulating a vector fluid, the circuit comprising: a delivery header (C1 ), designed to be supplied by a pressurised vector fluid source (P); a return header (C2), designed to be connected to a supply (P1 ) of the pressurised vector fluid source; a plurality of user branch-lines (L1 , L2, Li, Ln), arranged hydraulically in parallel between the delivery header (C1 ) and the return header (C2); wherein each user branch-line (L1 , L2, Li, Ln) includes a respective radiating user appliance (U1 , U2, Ui, Un); a plurality of electronic flowmeters (f1 , f2, fn) coupled to one of the delivery header and the return header, each electronic flowmeter being arranged so as to generate an electronic signal indicating a vector fluid flowrate (Q1 , Q2, Qi, Qn) in a respective one of the user branch-lines (L1 , L2, Li, Ln); a plurality of user branch-line electronic regulator valves (A1 , A2, An) coupled to the other one of the delivery header and the return header, each regulator valve being arranged and electronically controllable to regulate a vector fluid flowrate flowing through a respective user branch-line; an electronic DPCV regulator valve (AO), arranged at the inlet of the delivery header or outlet of the return header and electronically controllable so as to regulate a total flowrate (Q) through the header depending on a differential pressure (Dp) between the delivery header and the return header; an electronic differential pressure detection sensor, arranged and configured to detect a differential pressure (Dp) between the delivery header (C1 ) and the return header (C2) and to emit an electronic differential pressure signal; a central processing unit (CPU) which is connected to said electronic flowmeters (f1 , f2, fn), to said DPCV regulator valve (AO), to said differential pressure detection sensor and to said user branch-line regulator valves (A1 , A2, An) and is configured to receive electronic detection signals from said flowmeters and from said differential pressure detection sensor and to emit electronic control signals for regulating said user branch-line regulator valves and said DPCV regulator valve; wherein a respective design flowrate (Q_des_i) predefined for each user branch-line is stored in the processing unit; wherein, when in use during a method for regulating start-up of the heating system, the processing unit is configured to: receive a signal indicating a flowrate (Qi) of a vector fluid flowing in each user branch-line (Li) from the respective electronic flowmeter (f1 , f2, fn) of the user branch-line and obtain a respective vector fluid flowrate measurement signal for the user branch-line; regulate the opening of said DPCV regulator valve (AO) and of said user branch-line regulator valves (A1 , A2, An) so as to determine a flowrate (Qi) in each user branch-line of the hydraulic circuit greater than the respective predefined design flowrate (Q_des_i) of the user branch-line;

- vary the opening of the DPCV regulator valve so as to gradually reduce the total flow (Q) of fluid at the inlet of the delivery header or outlet of the return header, while monitoring: o the differential pressure (Dp) between the delivery header (C1 ) and the return header (C2), by means of the signal received from the differential pressure detection sensor; and o the flowrate (Qi) through each user branch-line, by means of the signals received from said electronic flowmeters, until a flowrate (Qi*) in a first user branch-line (Li*) is detected as being equal to the design flowrate (Q_des_i) for that user branch-line;

- store the value (Dp(tO)) of the differential pressure (Dp) between the delivery header (C1 ) and the return header (C2) detected when the design flowrate (Q_des_i*) is reached in said first branch-line (Li*) and set said value as a reference differential pressure (Dp set); for each user branch-line (Li) other than the first user branch-line (Li*): control the respective user branch-line electronic regulator valve so as to regulate the flowrate of the vector fluid through the user branch-line until the flowrate (Qi) in the user branch-line is equal to the design flowrate (Q_des_i) for that user branch-line, while monitoring and regulating the differential pressure between the headers by means of the signal received from the detection sensor and the control signal of the DPCV regulator valve (AO), so that each time the differential pressure is maintained or restored to the reference value (Dp set)

11) Heating system according to Claim 10, wherein the delivery header (C1 ) comprises a plurality of branch-off ducts (d 1 , c12, d n) each connected to a distribution duct of a respective user branch-line (L1 , L2, Li, Ln), and the return header (C2) comprises a plurality of branch-off ducts (c21 , c22, c2n), each connected to a return duct of a respective user branch-line (L1 , L2, Ln); wherein each user branch-line electronic regulator valve (A1 , A2, An) is arranged and can be electronically controlled to regulate the incoming or outgoing flow through a respective branch-off duct and therefore the flowrate passing through the user branch-line.

12) Heating system according to the preceding claim, wherein each electronic flowmeter is arranged along a branch-off duct of the said delivery header or return header so that a movable part of the flowmeter which interacts with the vector fluid flow in the branch-off duct moves with a variation in the flowrate through the branch-off duct.

13) Heating system according to one of the preceding claims, wherein, for regulating the vector fluid flowrate in the user branch-lines (Li) other than the first user branch-line (Li*), the processing unit (CPU) regulates the flowrate (Qi) of one user branch-line at a time by means of the respective electronic regulator valve and each time restores the differential pressure to the reference value (Dp set), regulating the overall flowrate (Q) by means of the DPCV regulator valve (AO).

14) Heating system according to one of the preceding claims, wherein the processing unit is configured to control each of the user branch-line regulator valves (A1 , A2, An) by means of a PI D control system, based on a respective flowrate signal (Qi) detected on the user branch-line (Li).

15) Heating system according to one of the preceding claims, wherein the processing unit is configured to control the DPCV regulator valve (AO) for regulating the total flowrate (Q) by means of a PID control system, based on a differential pressure signal indicating the differential pressure detected between the delivery header (C1 ) and the return header (C2).

16) Heating system according to one of the preceding claims, wherein the processing unit (CPU) is configured to regulate said DPCV regulator valve (AO) and said user branch-line regulator valves (A1 , A2, An) to a respective fully open position and to check that the flowrate (Qi) in each user branch-line is greater than the design flowrate (Q_des_i) predefined for the user branch-line by means of the user branch-line flowrate measurement signals.

17) Heating system according to the preceding claim, wherein, if the processing unit establishes that the flowrate measured on a user branch-line is less than the design flowrate for that user branch-line, it generates a warning signal indicating that the total flowrate is insufficient and/or increases the total flowrate supplied from the pressurised fluid source (P) to the delivery header (C1 ).

18) Heating system according to one of the preceding claims, wherein the electronic processing unit (CPU) is coupled to a user interface (app), preferably an app which can be run on a portable device connected to the electronic processing unit, the user interface being configured to acquire said predefined values of the design flowrate (Q_des_i) of each user branch-line and to forward them to the processing unit for storage thereof.