Fluid recirculation device, distribution system for sanitary water using said device

Description

FIELD OF THE FINDING

[0001] The object of the present invention is a recirculation device for a fluid, e.g. sanitary water, employable in civil and industrial field for energy control and optimization of hydraulic systems. The invention is also intended for a hydraulic system and a process for metering the thermal energy comprising said recirculation device.STATE OF THE ART

[0002] The typical architecture of a hydraulic system for distributing sanitary hot water for multi-family buildings provides for the installation of a series of users for each housing unit, served by a centralized heating system. Each housing unit can be provided with a recirculation device for allowing the water present in the hydraulic system to maintain a predetermined temperature such to ensure, within a pre-established time (within 30s from the request by the user), the dispensing of sanitary hot water.

[0003] A first example of a recirculation device comprises a delivery line adapted to serve the users of a housing unit and a recirculation line of sanitary hot water. On each line, a liter counter is present that is configured to meter the flow rate of sanitary water in transit through each line. The recirculation device is configured to measure, by means of the liter counter, the flow rate of sanitary water in transit on both lines: by executing the difference between the detected flow rates, the recirculation device is capable of determining the quantity of sanitary water consumed and the quantity of water employed for the recirculation. Even if the recirculation device described in the first example has a simple and inexpensive structure, these have several limitations and drawbacks. It is in fact indicated that such device, due to the architecture thereof, is subject to wear (the liter counters are always active and traversed by hot water in any condition, i.e. both in the condition in which the user draws hot water and in the recirculation condition) and does not allow executing a measurement of the thermal consumed energy lacking errors.

[0004] A second example of a recirculation device also comprising a delivery line adapted to serve the users of a housing unit and a line for recirculating sanitary hot water. On the delivery line, a liter counter is present that is configured to meter the flow rate of sanitary water in transit, while on the recirculation line a reducer of a sanitary water flow is present. The reducer allows the transit of a predetermined flow rate of sanitary water during the recirculation step (no request of sanitary water made by the user), lower than a flow rate of sanitary water in transit on the delivery line following a request of sanitary water by the user.

[0005] The recirculation device also comprises a control unit connected to the liter counter which is configured to measure the flow rate of sanitary water on the delivery line and, as a function thereof, attribute the consumption of water to a request of the user or to the recirculation.

[0006] Also the recirculation device described in the second example has several limitations and drawbacks. Such device in fact has a complex and costly structure that negatively impacts the overall system and maintenance costs. Such recirculation device has a liter counter arranged on the delivery line, hence always active, a condition that negatively affects the component wear. It is also indicated that the recirculation device of the second example is unable to provide a direct and precise measurement of the consumed thermal energy tied to the recirculation circuit.

[0007] Some known solutions of a hydraulic system for distributing sanitary hot water to a series of users are exemplified in the following documents.

[0008] Document EP 0 594 020 A1 relates to an installation for heating domestic water and for killing the legionella bacteria that comprises a cold-water supply line to a first heat exchanger with a disinfecting-water circuit, a circulating-water circuit with tapping points, a circulating line and a circulating pump.

[0009] Document DE 42 02 445 C1 describes a hot water system having a first side and a second side operatively connected by means of a heat exchanger. In detail, the first side comprises a water heater and a first circulating pump, whereas the second side comprises a second circulating pump and a series of tap points. The system further comprises a tapping by-pass bridging the heat exchanger to connect the first side and the second side directly.

[0010] Document EP 1 170 554 A2 shows a hydraulic system for distributing sanitary hot water comprising a primary circuit provided with an appliance providing hot water and a secondary circuit serving one or more users. The primary circuit and the secondary circuit are interconnected by means of a heat exchanger that transmits heat from the primary circuit's fluid to the service water in the secondary circuit.

[0011] Document US 4 936 289 A concerns an energy conservation apparatus for controlling the operation of a recirculating hot water distribution system which comprises a hot water heater, a supply line to one or more utilities, a return pipe interconnecting the end of the supply line back to water inlet line of the water heater to form a loop, an electrically operated recirculating pump in the loop, usually on the return pipe, that circulates the hot water around the loop.

[0012] Even if the above-described solutions are today employed for metering the energy consumptions of sanitary hot water (ACS) of multi-family buildings, the Applicant has detected that such solutions do not lack drawbacks and hence can be improved with regard to several aspects.OBJECT OF THE INVENTION

[0013] Object of the present invention is therefore that of resolving at least one of the drawbacks and / or limitations of the preceding solutions.

[0014] A first objective of the present invention is to provide a recirculation device that allows significantly limiting the waste of sanitary water and of energy, that is therefore capable of meeting the request of the sanitary hot water user in brief times. Another object of the present invention is to provide a recirculation device having a simple and compact structure that simultaneously allows precisely metering the volume of sanitary hot water consumed by the user and metering the thermal consumed energy for heating the recirculation line.

[0015] A further object of the present invention is to provide a recirculation device that can be easily integrated in a pre-existing home sanitary system without requiring invasive interventions and / or particular adjustments during installation.

[0016] These objects and still others, which will be clearer from the following description, are substantially reached by a recirculation device, a distribution system for sanitary hot water and a process of metering thermal energy using said device in accordance with one or more of the enclosed claims and / or of the following aspects.SUMMARY

[0017] In one aspect, a fluid recirculation device (1) is provided that is installable on a distribution system (100) for sanitary water, said distribution system (100) being of the type comprising: at least one heat generator (101), optionally a sanitary hot water storage device and / or a boiler, a general supply line (102) configured to receive the fluid exiting from the heat generator (101), a general outlet line (103) configured to serve the fluid to the heat generator (101), at least one delivery line (104) which places in fluid communication the general supply line (102) with at least one user (105), at least one recirculation line (106) which places said user (105) in fluid communication with the general outlet line (103), in which said recirculation device (1) comprises: at least one heat exchange unit (2) installable on the recirculation line (106) of the distribution system, said heat exchange unit (2) having at least one first and one second chamber (2a, 2b) distinct from each other, in which the first chamber (2a) has at least one delivery inlet (2a') and a delivery outlet (2a"), in which the second chamber (2b) has at least one recirculation inlet (2b') and a recirculation outlet (2b"), in which the recirculation inlet (2b') of the second chamber (2b) of the heat exchange unit (2) is connectable to a first section (106a) of the recirculation line which places the at least one user (105) in fluid communication with said heat exchange unit (2), in which the delivery outlet (2a") of the first chamber (2a) of the heat exchange unit (2) is connectable to a second section (106b) of the recirculation line which places in fluid communication said heat exchange unit (2) with the general fluid outlet (103), at least one first branch (3) configured to place in fluid communication the delivery line (104) with the delivery inlet (2a') of the first chamber (2a) of the heat exchange unit (2), at least one second branch (4) configured to place the delivery line (104) in fluid communication with the recirculation outlet (2b") of the second chamber (2b) of the heat exchange unit (2).

[0018] In one aspect according to the preceding aspect the recirculation device (1) is configured to define a recirculation condition in which at least part of the fluid passes through the recirculation line (106) traverses the second chamber (2b) of the heat exchange unit (2).

[0019] In one aspect according to any one of the preceding aspects the heat exchange unit (2), during the recirculation condition, is configured to: receive fluid entering the second chamber (2b) by means of the recirculation inlet (2b'), eject fluid from the second chamber (2b) by means of the recirculation outlet (2b").

[0020] In one aspect according to any one of the preceding aspects, during the recirculation condition, at least part of the fluid passes through the delivery line (104) traverses the first chamber (2a) of the heat exchange unit (2). In one aspect according to any one of the preceding aspects the heat exchange unit (2), during the recirculation condition, is configured to: receive fluid entering the first chamber (2a) by means of the delivery inlet (2a'), eject fluid from the first chamber (2a) by means of the delivery outlet (2a").

[0021] In one aspect according to any one of the preceding aspects the heat exchange unit (2) is configured to allow a heat exchange between the fluid circulating in the first chamber (2a) and the fluid present, optionally circulating, in the second chamber (2b).

[0022] In one aspect according to any one of the preceding aspects the heat exchange unit (2) comprises at least one heat exchanger. In one aspect according to any one of the preceding aspects the heat exchange unit (2) comprises an exchanger of plate type. In one aspect according to any one of the preceding aspects the heat exchanger is of parallel flow type. In one aspect according to any one of the preceding aspects the exchanger is of plate type with parallel.

[0023] In one aspect according to any one of the preceding aspects the device is configured to define at least one main operating condition in which a main part of the fluid arriving from the general supply line (102) traverses the delivery line (104) in order to reach the user (105).

[0024] In one aspect according to any one of the preceding aspects the device comprises at least one hydraulic sensor (6') installable on at least one between the first branch (3) and the second section (106b) of the recirculation line (106), in which said hydraulic sensor (6') is configured to generate at least one signal relative to at least one parameter representative of a fluid flow. In one aspect according to the preceding aspect the hydraulic sensor (6') comprises at least one flowmeter. In one aspect according to any one of the preceding aspects the parameter representative of a fluid flow emitted by the hydraulic sensor (6') comprises at least one from among: a flow rate of the fluid, a fluid velocity, a fluid pressure difference.

[0025] In one aspect according to any one of the preceding aspects the hydraulic sensor (6') is configured to be installed on the second section (106b) of the recirculation line (106), in proximity to the delivery outlet (2a") of the heat exchange unit (2), or the hydraulic sensor (6') is configured to be installed upstream of the heat exchange unit (2).

[0026] In one aspect according to any one of the preceding aspects the device comprises: at least one first temperature sensor (12) installed on the first branch (3) and configured to generate a signal representative of a temperature value of the fluid traversing said first branch (3), at least one second temperature sensor (13) configured to be installed on the second section (106b) of the recirculation line (106) and configured to generate a signal representative of a temperature value of the fluid traversing said second section (106b).

[0027] In one aspect according to any one of the preceding aspects the first sensor (12) is placed at the delivery inlet (2a') of the heat exchange unit (2). In one aspect according to any one of the preceding aspects the first sensor (12) is placed, with respect to a direction of advancement of the fluid along the first branch (3), immediately upstream of the delivery inlet (2a') of the first chamber (2a) of the heat exchange unit (2).

[0028] In one aspect according to any one of the preceding aspects the device comprises at least one control unit (50) connected to the hydraulic sensor (6'), to the first temperature sensor (12) and to the second temperature sensor (13), said control unit (50) being configured to receive the signals from said sensors (6', 12, 13) and determine, as a function of said signals and at least during the recirculation condition, a value of instantaneous thermal power exchanged by the heat exchange unit (2) in order to determine the energy exchanged in a predetermined time interval.

[0029] In one aspect according to any one of the preceding aspects the control unit (50), at least during the recirculation condition, is configured to: receive the signal emitted by the hydraulic sensor (6') and, as a function of said signal, determine a value of a fluid flow rate traversing the first branch (3) and / or the second section (106b) of the recirculation line (106), receive the signal emitted by the first temperature sensor (12) and, as a function of said signal, determine a temperature value of the fluid traversing the first branch (3), receive the signal emitted by the second temperature sensor (13) and, as a function of said signal, determine a temperature value of the fluid traversing the second section (106b) of the recirculation line (106).

[0030] In one aspect according to any one of the preceding aspects the control unit (50), as a function of the determined values of flow rate and temperature, is configured to determine the instantaneous thermal power exchanged by the heat exchange unit (2) in order to determine the energy exchanged in a predetermined time interval.

[0031] In one aspect according to any one of the preceding aspects the control unit (50), during the recirculation condition, is configured to store: the temperature value of the fluid passes through the first branch (3), the temperature value of the fluid passes through second section of the recirculation line (106b), the flow rate value of the fluid traversing the first branch (3) and / or the second section (106b) of the recirculation line (106).

[0032] In one aspect according to any one of the preceding aspects the control unit (50) is configured to calculate a value of thermal energy (E) exchanged by the heat exchange unit (2) in a predetermined time interval, by means of the following formula: E = ∫ t 1 t 2 CpQ Δ Tdt wherein: E is the thermal energy exchanged by the heat exchange unit, Cp is the specific heat of the fluid, Q is the flow rate value of the fluid calculated as a function of the signal emitted by the hydraulic sensor, ΔT is the value calculated from the difference of the temperature value of the fluid traversing said first branch (3) and the temperature value of the fluid traversing said second section (106b), t1 and t2 are the ends that define the time interval.

[0033] In one aspect according to any one of the preceding aspects the device comprises at least one flow regulator (5) in fluid communication with the delivery outlet (2a") of the heat exchange unit (2) and configured to vary the flow rate of the fluid traversing the first chamber (2a) of the heat exchange unit (2).

[0034] In one aspect according to any one of the preceding aspects the flow regulator (5) is configurable in at least: one open position in which it allows the flow of fluid through the first chamber (2a) of the heat exchange unit (2) to define the recirculation condition of the recirculation device, one closed position in which it prevents the flow of the fluid through the first chamber (2a) of the heat exchange unit (2) to define the main operating condition of the recirculation device (1).

[0035] In one aspect according to any one of the preceding aspects the flow regulator (5) is configurable between the open position and the closed position as a function of at least one reference parameter comprising at least one from among: predetermined time intervals, a command signal, a temperature value of the fluid present in the heat exchange unit, a temperature value of the fluid present within the recirculation line.

[0036] In one aspect according to any one of the preceding aspects the flow regulator (5) is a thermostatic valve. In one aspect according to any one of the preceding aspects the thermostatic valve is configured to determine a temperature value of the fluid downstream of the delivery outlet (2a") of the heat exchange unit (2). In one aspect according to any one of the preceding aspects the thermostatic valve is configurable between the open position and the closed position when the temperature value detected by the same thermostatic valve is greater than a predetermined threshold, optionally equal to 35°C. In one aspect according to any one of the preceding aspects the thermostatic valve is configurable between the closed position and the open position when the temperature value detected by the same thermostatic valve is lower than the predetermined threshold.

[0037] In one aspect according to any one of the preceding aspects the control unit (50) is directly connected to the flow regulator (5) and configured to send the latter at least one actuation signal. In one aspect according to any one of the preceding aspects the flow regulator (5), following the receipt of the actuation signal, is configurable between the open position and the closed position and vice versa.

[0038] In one aspect according to any one of the preceding aspects the flow regulator (5) is: active on at least one between the first branch (3), and / or configured to be arranged on the second section (106b) of the recirculation line (106).

[0039] In one aspect according to any one of the preceding aspects the flow regulator (5) is a fluid interception valve. In one aspect according to any one of the preceding aspects the control unit (50) is active in command of said fluid interception valve and being configured to send, at predetermined time intervals, an actuation signal to said fluid interception valve in order to configure it between the open position and closed position.

[0040] In one aspect according to any one of the preceding aspects the device comprises at least one pump (17) arranged on the first section (106a) of the recirculation line (106). In one aspect according to the preceding aspect the pump (17) is configured to operate at least between: an active condition in which the same moves the fluid through the second chamber (2b) of the heat exchange unit (2), and a disabled condition in which the pump (17) does not move the fluid.

[0041] In one aspect according to any one of the preceding aspects the pump (17) operates in the active condition at least during the recirculation condition of the recirculation device (1).

[0042] In one aspect according to any one of the preceding aspects the control unit (50) is connected to and activated in command of said pump (17). In one aspect according to any one of the preceding aspects the control unit is configured to activate the pump (17) as a function of at least one reference parameter comprising at least one selected in the group from among: the temperature of the fluid on the second section of the recirculation line (106), the temperature of the fluid on the first section of the recirculation line (106), predetermined time intervals. In one aspect according to any one of the preceding aspects the device comprises at least one auxiliary temperature sensor (9) in fluid communication with the first section (106a) of the recirculation line (106), configured to generate a signal representative of a temperature of the fluid on the first section (106a) of the recirculation line (106).

[0043] In one aspect according to any one of the preceding aspects the auxiliary temperature sensor (9) is connected to the control unit (50). In one aspect according to any one of the preceding aspects the auxiliary temperature sensor (9) is configured to send to the control unit (50) a signal representative of the temperature of the fluid on the first section (106a) of the recirculation line (106). In one aspect according to any one of the preceding aspects the auxiliary temperature sensor (9) is configured to send to the control unit (50) a signal representative of the temperature of the fluid on the / a first connecting branch (21).

[0044] In one aspect according to any one of the preceding aspects the control unit (50), following the receipt of the signal representative of the temperature of the fluid on the first section (106a) of the recirculation line (106), optionally on the first connecting branch (21), is configured to: determine a temperature value of the fluid on the first section (106a) of the recirculation line (106), compare said value with a predetermined threshold value, optionally equal to 28°C.

[0045] In one aspect according to any one of the preceding aspects the control unit (50), if the determined temperature value is lower than the predetermined threshold value, is configured to determine the start of the recirculation condition (optionally activate the recirculation).

[0046] In one aspect according to any one of the preceding aspects the control unit (50), during the recirculation condition, is configured to: optionally send an actuation signal to the flow regulator (5), allowing the passage thereof between the closed position and the open position, send a command signal to the pump (17) allowing the passage thereof from the disabled condition to the active condition, store a first time instant (t1) in which the control unit (50) sends the command signal or the actuation signal, receive, from the first sensor, the temperature signal representative of the temperature value on the first branch (3), receive, from the second sensors the temperature signal representative of the temperature value on the second section (106b) of the recirculation line (106).

[0047] In one aspect according to any one of the preceding aspects the auxiliary temperature sensor (9), during the recirculation condition, is configured to send to the control unit (50) the signal representative of the temperature of the fluid on the first section (106a) of the recirculation line (106).

[0048] In one aspect according to any one of the preceding aspects the control unit, during the recirculation condition, is configured to: receive, from the auxiliary temperature sensor (9), the temperature signal of the fluid on the first section (106a) of the recirculation line (106), compare said value with a predetermined threshold value, if said temperature value is greater than the predetermined threshold, the control unit (50) is configured to determine the end of the recirculation condition.

[0049] In one aspect according to any one of the preceding aspects the control unit, following the determination of the end of the recirculation condition, is configured to: optionally send an actuation signal to the flow regulator (5), allowing the passage thereof between the open position and the closed position, send a command signal to the pump (17) allowing the passage thereof from the active condition to the disabled condition, store the time instant (t2) in which sends the command signal or the actuation signal.

[0050] In one aspect according to any one of the preceding aspects the control unit (50) is configured to calculate the value of thermal energy (E) following the determination of the end of the recirculation condition. In one aspect according to any one of the preceding aspects the control unit (50) is also configured to store the calculated value of thermal energy (E).

[0051] In one aspect according to any one of the preceding aspects the device comprises a display directly connected to the control unit (50) and configured to show the value of thermal energy (E) calculated by the control unit (50).

[0052] In one aspect according to any one of the preceding aspects the device comprises at least one auxiliary flow regulator (8) in fluid communication with the recirculation inlet (2b') of the heat exchange unit (2). In one aspect according to the preceding aspect the auxiliary flow regulator (8) is configured to vary the flow rate of the fluid traversing the second chamber (2b) of the heat exchange unit (2).

[0053] In one aspect according to any one of the preceding aspects the auxiliary flow regulator (8) comprises a valve, positionable periodically or at regular intervals or following a command or following the detection of an event, at least between: an open position in which it allows the passage of the fluid through the second chamber (2b) of the heat exchange unit (2), a closed position in which it prevents at least in part the passage of the fluid through the second chamber (2b) of the heat exchange unit (2).

[0054] In one aspect according to any one of the preceding aspects the auxiliary flow regulator (8) is a thermostatic valve configured to determine a temperature value upstream of the recirculation inlet of the heat exchange unit (2). In one aspect according to any one of the preceding aspects the thermostatic valve defined by the auxiliary flow regulator (8) is movable between the open position and the closed position as a function of said detected temperature value.

[0055] In one aspect according to any one of the preceding aspects the thermostatic valve is movable between the open position and the closed position when the temperature value detected by the same thermostatic valve is greater than a predetermined threshold, optionally equal to 35°C. In one aspect according to any one of the preceding aspects the thermostatic valve is movable between the closed position and the open position when the temperature value detected by the same thermostatic valve is lower than the predetermined threshold.

[0056] In one aspect according to any one of the preceding aspects the first branch (3) is directly connectable to the delivery line in a connecting point interposed between the general supply line (102) and the user. In one aspect according to any one of the preceding aspects the second branch is directly connectable to the delivery line in a connecting point interposed between the first branch (3) and the user (105) downstream of the connecting point of the first branch (3).

[0057] In one aspect according to any one of the preceding aspects the first branch (3) has at least one device for intercepting the flow (3a), optionally a check valve, configured to allow the passage of the fluid only towards the delivery inlet (2a') of the heat exchange unit (2).

[0058] In one aspect according to any one of the preceding aspects the second branch (4) has at least one device for intercepting the flow (4a), optionally a check valve, configured to prevent the passage of the fluid towards the recirculation outlet (2b") of the heat exchange unit (2).

[0059] In one aspect according to any one of the preceding aspects the device comprises at least one intermediate branch (11) in fluid communication between the first and the second branch (3, 4). In one aspect according to the preceding aspect the intermediate branch (11) has at least one fluid interception device. In one aspect according to any one of the preceding aspects the fluid interception device active on the intermediate branch (11) comprises a check valve, configured to prevent the transit of the same fluid from the second branch (4) towards the first branch (3).

[0060] In one aspect according to any one of the preceding aspects the device comprises at least one hydraulic sensor (7) directly connected to the intermediate branch (11), optionally upstream of the element for intercepting fluid. In one aspect according to the preceding aspect the hydraulic sensor (7) is configured to detect, at least during the main operating condition of the device (1), a flow rate value of the fluid in transit through said intermediate branch (11).

[0061] In one aspect a distribution system for a fluid is provided, comprising: at least one heat generator (101), a general supply line (102) configured to distribute the fluid exiting from the heat generator (101), a general outlet line (103) configured to serve return fluid to the heat generator (101), at least one delivery line (104) which places in fluid communication the general supply line (102) to at least one user (105), at least one recirculation line (106) which places in fluid communication said at least one user (105) with the general outlet line (103), a recirculation device (1) according to any one of the preceding claims.

[0062] In one aspect according to the preceding aspect the first (106a) of the recirculation line (106) is connected to the recirculation inlet (2b') of the heat exchange unit (2) and the second section (106b) of the recirculation line (106) is connected to the delivery outlet (2a") of the heat exchange unit (2).

[0063] In one aspect according to the two preceding aspects the system comprises a first fluid interception valve (16a) in fluid communication with the delivery line, interposed between the general supply line (102) and the first branch (3) of the recirculation device, said first valve (16a) being configured to selectively allow the transit of the fluid along the delivery line.

[0064] In one aspect according to any one of the preceding aspects of a system, the latter comprises a second fluid interception valve (16b) in fluid communication with the delivery line, interposed between the second branch (4) of the recirculation device and the user (105), said second valve (16b) being configured to selectively prevent the transit of the fluid towards the user.

[0065] In one aspect according to any one of the preceding aspects of a system, the latter comprises a third fluid interception valve (16c) in fluid communication with the recirculation line, optionally on the first section (106a) of the recirculation line (106), interposed between the user (105) and the recirculation device, said third valve (16c) being configured to selectively prevent the transit of the fluid from the user (105) towards the recirculation device (1).

[0066] In one aspect a process is provided for metering thermal energy executed by means of a device recirculation (1) according to any one of the preceding aspects. In one aspect according to the preceding aspect the process comprises the steps of: determining a flow rate value of the fluid, downstream or upstream, of the delivery outlet (2a") of the recirculation device, determining a temperature value of the fluid upstream of the delivery inlet (2a') of the recirculation device, determining a temperature value of the fluid downstream of the delivery outlet (2a") of the recirculation device, determining a thermal power, optionally instantaneous, exchanged by the heat exchange unit (2), as a function of the flow rate value and of the temperature values of the fluid upstream of the delivery inlet (2a') and downstream of the delivery outlet (2a").

[0067] In one aspect according to the preceding aspect the step of determining the thermal energy exchanged by the heat exchange unit (2) is executed by the control unit (50), which is configured to determine the thermal energy exchanged by the heat exchange unit (2) in a predetermined time interval (t1, t2) according to the following formula: E = ∫ t 1 t 2 CpQ Δ Tdt wherein: Cp is the specific heat of the fluid, Q is the flow rate value of the fluid, downstream or upstream, of the delivery outlet (2a"), ΔT is the value of temperature difference measured between the delivery inlet (2a') and the delivery outlet (2a").

[0068] In one aspect according to any one of the preceding aspects of a process, the latter comprises a communication step, in which the control unit (50) is configured to transmit the calculated value of thermal energy to an external database.

[0069] In one aspect, a use of the recirculation device is provided in accordance with any one of the preceding aspects for metering the thermal energy of hydraulic systems, e.g. of multi-family buildings.BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Several embodiments and several aspects of the finding will be described hereinbelow with reference to the enclosed drawings, provided only as a non-limiting example in which: Figure 1 is a schematic view of a known distribution system for sanitary water, Figures 2 and 3 are schematic views of a recirculation device in accordance with the present invention installed on a distribution system for sanitary water, Figure 4 is a further schematic view of a distribution system for sanitary water comprising at least one recirculation device. CONVENTIONS AND DEFINITIONS

[0071] It is noted that, in the present detailed description, corresponding parts illustrated in the various figures are indicated with the same reference numbers. The figures could illustrate the object of the invention by means of representations not in scale; therefore, parts and components illustrated in the figures relative to the object of the invention might only regard schematic representations.

[0072] The terms 'upstream' and 'downstream' refer to a direction of advancement of a fluid flow through the recirculation device in accordance with the present invention or with respect to a direction of advancement of a fluid flow within a hydraulic system comprising said device. The fluid can be a liquid, e.g. water of a water supply network.

[0073] The recirculation device and / or the hydraulic system described and claimed hereinbelow can comprise / use at least one control unit 50 set for controlling operating conditions implemented by the same device / system and / or for controlling the steps of the process of metering the thermal energy. The control unit 50 can be a single unit or be formed by a plurality of distinct control units depending on the design choices and on the operating needs. With control unit, it is intended a component of electronic type, which can comprise at least one from among: a digital processor (CPU), a circuit of analog type, or a combination of one or more digital processors with one or more circuits of analog type. The control unit can be "configured" or "programmed" in order to execute several steps: this can be attained in practice with any means that allows configuring or programming the control unit. For example, in case of a control unit comprising one or more CPUs and one or more memories, one or more programs can be stored in appropriate storage banks connected to the CPU or to the CPUs; the program or programs contain instructions which, when executed by the CPU or by the CPUs, program or configure the control unit in order to execute the operations described in relation to the control unit. Alternatively, if the control unit is, or comprises, circuitry of analog type, then the circuit of the control unit can be designed in order to include circuitry configured, during use, to process electrical signals in a manner such to execute the steps relative to the control unit.

[0074] Parts of the process described herein can be attained by means of a data processing unit, or control unit, technically substitutable with one or more computers conceived in order to execute a portion of software or firmware program loaded on a storage medium. Such software program can be written in any one programming language of known type. The computers, if in a number equal to two or more, can be connected to each other by means of a data connection such that their computing powers are shared in any manner; the same computers can therefore be installed in positions that are even geographically different, attaining by means of the aforesaid data connection a distributed computing environment.

[0075] The data processing unit, or control unit, can be a processor of general purpose type configured to execute one or more parts of the process identified in the present disclosure through the software or firmware program, or be an ASIC or dedicated processor or a FPGA, specifically programmed in order to execute at least part of the operations of the process described herein. The storage medium might not be transient and can be inside or outside the processor, or data processing unit, and can - specifically - be a storage geographically situated remotely with respect to the computer. The storage medium can also be physically divided into multiple portions, or in cloud form, and the software or firmware program can physically provide for portions stored on storage portions that are geographically divided from each other.DETAILED DESCRIPTIONRecirculation device

[0076] Reference number 1 overall indicates a recirculation device for a fluid installable within a system 100 for distributing sanitary hot water. In figure 4, a system for distributing and / or dispensing sanitary water was represented, for example employable within multi-family housing units, within which the recirculation device 1 is installed. The system 100 has a heat generator 101, optionally comprising a sanitary hot water storage device and / or a boiler, for heating sanitary water drawn from a water supply network. The system can also comprise at least one user 105 in order to serve a sanitary hot water to a system user. In the embodiment of the system shown in figures 2 to 4, only one user was schematized, nevertheless it is possible to arrange a system having a plurality of users and configured to serve each user simultaneously.

[0077] The system can further comprise a general delivery line 102 for the transport of the fluid exiting from the heat generator 101, towards each housing unit / apartment of the multi-family building, as well as a general outlet line 103 configured to serve the heat generator 101 with the sanitary water exiting from each housing unit. The system can comprise a delivery line 104 which places in fluid communication the general supply line 102 with each user 105. Furthermore, the system 100 comprises at least one recirculation line 106 configured to place in fluid communication each user 105 with the general outlet line 103. In particular, the recirculation line 106 can comprise at least one first section 106a in fluid communication with the user 105 and a second section 106b in fluid communication with the general return line 103. It is noted that within multi-family buildings, it is always recommended to arrange a distribution / dispensing system for sanitary water comprising a recirculation line set to serve sanitary hot water to the different users. Indeed, the arrangement of a system comprising a recirculation line renders the system in accordance with the UNI 9182 standard, which provides for the supply of sanitary hot water to the different users, to the pressure and design flow rate within 30s from the request by the user.

[0078] For this reason, in the multi-family buildings, a distribution of sanitary water is attained having a delivery line and a corresponding return line (see figure 1 representative of a known system). In this manner the delivery line is always hot and the request can be satisfied in the requested times. It is noted that in some known systems, there is the problem of metering the energy necessary for heating / cooling the recirculation line, which is assigned to the recirculation device 1 detailed below.

[0079] The recirculation device 1 can comprise at least one heat exchange unit 2 installable in fluid communication with the system 100 and configured to allow the heat exchange between a fluid passes through the delivery line 104 and a fluid passes through the recirculation line 106. In the figures, the heat exchange unit was represented as a heat exchanger having a first and a second chamber 2a, 2b, distinct from each other and isolated, each of which configured to allow the transit of the fluid traversing the heat exchange unit. In particular, the first and the second chamber 2a, 2b allow the passage of fluid parts through the heat exchange unit. The heat exchange unit therefore allows the respective fluid parts traversing the first and second chambers 2a, 2b, to exchange thermal energy.

[0080] In particular, the first chamber 2a has a delivery inlet 2a' in fluid communication with the delivery line 104 and configured to allow the inlet of the fluid within the first chamber 2a. The first chamber 2a also has a delivery outlet 2a" configured to place in fluid communication the heat exchange unit with the recirculation line 106, in particular with the second section of the recirculation line 106b. The second chamber 2b in turn comprises a recirculation inlet 2b' configured to receive a fluid from the recirculation line 106, in particular from the first section 106a of the recirculation line 106, and a recirculation outlet 2b" configured to place the second chamber 2b of the heat exchange unit in fluid communication with the delivery line 104.

[0081] From the structural standpoint, the heat exchange unit 2 can for example be a plate heat exchanger with concurrent or countercurrent flow direction. Nevertheless it is also possible to use a heat exchange device alternative to the heat exchanger shown, such as for example a hydraulic separator.

[0082] As shown in figures 2 and 3, the recirculation device is connectable to the system by means of a predetermined number of ducts. The recirculation device can in fact comprise a first branch 3 configured to place in fluid communication the delivery line 104 with the delivery inlet 2a' of the first chamber 2a of the heat exchange unit 2. It is noted that the first branch 3 is directly connectable to the delivery line 104 at a connecting point defined interposed between the general supply line 102 and the user 105. In a second embodiment of the device shown in figure 3, the device can have at least one device for intercepting the flow 3a, optionally a check valve, configured to allow the passage of the fluid only towards the delivery inlet 2a' of the first chamber 2a of the heat exchange unit 2.

[0083] The recirculation device can also comprise a second branch 4 configured to place in fluid communication the delivery line 104 with the recirculation outlet 2b" of the second chamber 2b of the heat exchange unit 2. In particular, the second branch 4 is connectable to the delivery line 104 at a connecting point defined interposed between the connecting point between the first branch 3 and the delivery line 104 and the user 105. In other words, the second branch 4 is connected to the delivery line 104 at a connecting point downstream of the connecting point of the first branch 3. The recirculation device has at least one fluid interception device 4a, optionally a check valve, in fluid communication with the second branch 4 and configured to prevent the passage of the fluid from the delivery line 104 towards the recirculation outlet 2b" of the heat exchange unit 2.

[0084] The recirculation device can further comprise at least one intermediate branch 11 in fluid communication between the first and the second branch 3, 4. The intermediate branch 11 substantially defines an extension of the delivery line 104 of the system, placing in fluid communication the first and the second branch 3, 4 at the respective connecting points with the delivery line 104.

[0085] The recirculation device can also comprise flow rate sensor 7 (alternatively a volume sensor) in fluid communication with the intermediate branch and configured to measure the flow rate and / or the volume of the fluid traversing the same intermediate branch 11. The flow rate sensor 7 can for example be a turbine volumetric counter (liter counter), configured to meter the flow rate and / or the volume of water entering the system.

[0086] The recirculation device can have at least one fluid interception device, optionally a check valve, in fluid communication with the intermediate branch 11 and configured to prevent the passage of the fluid through the same intermediate branch 11. In particular, the recirculation device comprises a first and a second fluid interception device 7a, 7b in fluid communication with the intermediate branch, respectively active at one section of the same intermediate branch 11 upstream and downstream of the flow rate sensor 7.

[0087] It is noted that in the enclosed figures, a recirculation device was shown comprising the first branch 3, the second branch 4 and the intermediate branch 11. Nevertheless it is possible to attain a recirculation device lacking the first branch 3, the second branch 4 and the intermediate branch 11.

[0088] The recirculation device can comprise a first connecting branch 21 configured to place in fluid communication the recirculation inlet 2b' of the second chamber 2b of the heat exchange unit 2 with the recirculation line 106, in particular with the first section 106a.

[0089] The recirculation device 1 can further comprise a second connecting branch 20 configured to place in fluid communication the delivery outlet 2a" of the first chamber 2a of the heat exchange unit 2 with the recirculation line 106, optionally with the second section 106b. The recirculation device 1 is then connectable to the distribution system for sanitary water 100 by means of the following ducts: the first branch 3 connectable between the delivery line 104 and the delivery inlet 2a' of the first chamber 2a of the heat exchange unit 2, the second connecting branch 20 connectable between the second section of the recirculation line 106b and the delivery outlet 2a" of the first chamber 2a of the heat exchange unit, the second connecting branch 21 connectable between the first section of the recirculation line 106a and the recirculation inlet 2b' of the second chamber 2b of the heat exchange unit, the second branch 4 connectable between the delivery line 104 and the recirculation outlet 2b" of the second chamber of the heat exchange unit 2.

[0090] It is further noted that the second connecting branch 20 and the first branch 3 place in fluid communication the first chamber 2a of the heat exchange unit 2, respectively with the second section 106b of the recirculation line 106 and the delivery line 104. Analogously, the first connecting branch 21 and the second branch 4 place in fluid communication the second chamber 2b of the heat exchange unit 2, respectively with the first section 106a of the recirculation line 106 and the delivery line 104.

[0091] The recirculation device can further comprise at least one hydraulic sensor 6' installable on at least one between the first branch 3 and the second connecting section 20, configured to generate at least one signal relative to at least one parameter representative of a fluid flow. In particular, the parameter representative of the fluid flow rate emitted by the hydraulic sensor 6', comprises at least one from among: a flow rate of the fluid, a fluid velocity or a fluid pressure difference. Preferably, the hydraulic sensor 6' generates an analog signal (under voltage) or a digital signal, representative of a flow rate of the fluid exiting from the first chamber 2a. The hydraulic sensor 6' can be installed on the second section 106b of the recirculation line 106, in proximity to the delivery outlet 2a" of the heat exchange unit 2. It is noted that the hydraulic sensor 6' was represented in figures 2 and 3 as a turbine volumetric counter (liter counter) adapted to attain a measurement of the flow rate of the fluid that traverses it. Nevertheless it is possible to arrange a flowmeter active on the second connecting branch 20 and in fluid communication with the latter, configured to carry out a direct measurement of the flow rate of the fluid that traversed it. The hydraulic sensor 6' is also configured to send the signal representative of the fluid flow rate and send it to a control unit 50, the latter detailed below.

[0092] The recirculation device 1 can also comprise a first and a second temperature sensor 12, 13 respectively installable on the first branch 3 and on the second section 106b of the recirculation line 106. In particular, the first temperature sensor 12 is active on the first branch 3 and configured to generate a signal representative of a temperature value of the fluid passes along said branch. The first sensor can be installed at, in particular immediately upstream, the delivery inlet 2a' of the first chamber 2a of the heat exchange unit, in a manner such to allow the detection of the temperature of the fluid entering the first chamber 2a of the heat exchange unit 2. In particular, the first temperature sensor 12 is configured to be installed immediately upstream of the delivery inlet 2a' of the first chamber 2a of the heat exchange unit 2, in order to precisely detect the temperature of the fluid entering the first chamber 2a. The first sensor 12 can be further connected to the control unit 50 and configured to send, to the latter, the signal representative of the temperature value of the fluid on the first branch 3.

[0093] The second sensor 13 is active on the second connecting branch 20 and configured to generate a signal representative of a temperature of the fluid passes along said branch. In particular, the second sensor can be installed at, in particular immediately downstream, the delivery outlet 2a" of the first chamber 2a of the heat exchange unit, in a manner such to allow the detection of the temperature of the fluid exiting from the first chamber 2a. The second sensor 13 can be further connected to the control unit 50 and configured to send, to the latter, the generated signal representative of the temperature value of the fluid on the second connecting branch 20.

[0094] It is further noted that the first and the second temperature sensor 12, 13 can be immersion sensors placed in fluid communication respectively with the first branch 3 and with the second connecting branch 20.

[0095] The recirculation device can further comprise at least one control unit 50 connected to the hydraulic sensor 6', to the first and to the second temperature sensor 12, 13 and configured to receive the respective signals generated by each of the abovementioned sensors 6', 12, 13 in order to determine a value of thermal power exchanged by the heat exchange unit 2 in a predetermined time interval. In particular, the control unit is configured to: receive the signal emitted by the hydraulic sensor 6' and, as a function of the latter, determine a value of a flow rate (Q) of fluid entering or exiting from the first chamber 2a of the heat exchange unit 2, receive the signal emitted by the first temperature sensor 12 and, as a function of the latter, determine a temperature value T1 of the fluid traversing the first branch 3, receive the signal emitted by the second temperature sensor 13 and, as a function of the latter, determine a temperature value T2 of the fluid traversing the second section 106b of the recirculation line 106.

[0096] The control unit 50, as a function of the determined temperature values and flow rate, is configured to determine the thermal energy exchanged by the heat exchange unit 2 in a predetermined time interval. In particular, the control unit 50 is configured to calculate a value of thermal energy exchanged by the heat exchange unit 2 in a predetermined time interval, by means of the following formula: E = ∫ t 1 t 2 CpQ Δ Tdt wherein: E is the thermal energy exchanged by the heat exchange unit, Cp is the specific heat of the fluid, Q is the flow rate value of the fluid calculated as a function of the signal emitted by the hydraulic sensor, ΔT is the value calculated from the difference of the temperature values T2-T1, t1 and t2 are the ends that define the time interval.

[0097] The recirculation device can further comprise at least one pump 17 in fluid communication with the first connecting branch 21 and configured to operate at least between an active condition in which it moves the fluid through the second chamber 2b of the heat exchange unit 2 and a disabled condition in which it does not move the fluid. In other words, the pump 17 is selectively activatable in order to allow the movement of the fluid through the second chamber 2b of the heat exchange unit 2. In particular, the pump 17, during the active condition, allows the movement of the fluid through the first section 106a of the recirculation line 106, the first connecting branch 21 and through the second branch 4. The pump 17 can also be connected to the control unit 50 and configured to receive from the latter, periodically or at regular intervals or following a command or following the detection of an event, a command signal adapted to trigger the active condition or the disabled condition.

[0098] In the first embodiment of the invention shown in figure 2, the recirculation device can further comprise an auxiliary temperature sensor 9 active on the first connecting branch 21 and configured to generate a signal representative of a temperature value of the fluid passes through the first connecting branch 21. Indeed, the auxiliary temperature sensor 9 can be connected to the control unit 50 and configured to send, to the latter, the signal representative of the detected temperature value. The control unit 50, following the receipt of the signal representative of the detected temperature value from the auxiliary temperature sensor 9, is configured to determine a temperature value of the fluid traversing the first section 106a of the recirculation line 106 and compare said temperature value with a predetermined threshold value, optionally equal to 28°C. If the temperature value of the fluid on the first section 106a of the recirculation line 106 is lower than the predetermined threshold, the control unit 50 is configured to send the command signal to the pump 17, which, if it is in the disabled condition, executes the passage from the disabled condition to the active condition. Analogously, if the temperature value of the fluid on the first section 106a of the recirculation line 106 is greater than the predetermined threshold, the control unit 50 is configured to send the command signal to the pump 17, which, if it is in the active condition, executes the passage from the active condition to the disabled condition.

[0099] The auxiliary temperature sensor 9 can for example be a temperature immersion sensor, in communication with the fluid traversing the first connecting branch 21.

[0100] The operating logic will now be described. The recirculation device 1 is configured to define at least one main operating condition and a recirculation condition as a function of the temperature of the fluid passes through the abovementioned pipes of the device itself or following a request for sanitary hot water by a user.

[0101] It is noted that, in figures 2 and 3, respectively the first and second embodiments of the invention are represented. Both allow metering the consumed energy in order to attain the heating of the fluid passing through the recirculation line, but they have different operating logics.

[0102] With regard to the first embodiment shown in figure 2, the fluid (sanitary hot water), reaches the single housing unit, passing through the general supply line 102 and subsequently the delivery line 104. Following a request of sanitary hot water by the user, the fluid traverses the delivery line and the intermediate branch 11, serving the user, thus defining the main operating condition. Still during the main operating condition, but considering all the users closed, the recirculation device 1 allows the sanitary hot water to remain on the first section 106a of the recirculation line 106, in the delivery line 104 and in the intermediate branch 11 of the recirculation device. It is noted that during the latter operating condition, the fluid exiting from the intermediate branch cannot reach, by means of the second branch 4, the second chamber 2b of the heat exchange unit 2, due to the fluid interception device 4a, which allows the passage of the fluid only towards a direction exiting from the second chamber 2a of the heat exchange unit 2. It is also noted that during the main operating condition, the pump 17 is in the disabled condition, therefore the fluid remains in the first branch 106a of the recirculation line and in the second branch 4. Furthermore, during the latter operating condition, the fluid passes through the delivery line 104 and the intermediate branch as long as the pressure of the fluid in the first branch 3 is greater than the pressure of the fluid in the first section 106a of the recirculation line. When such condition is no longer verified, the fluid passes through the delivery line, transits through the first branch 3, the first chamber 2a of the heat exchange unit 2, the second connecting branch 20, the second section 106b of the recirculation line 106, flowing towards the general outlet line 103. In the main operating condition of the device 1, the auxiliary temperature sensor 9 generates the signal representative of the temperature of the fluid on the first connecting branch 21 and sends the latter signal to the control unit 50. The control unit 50 receives the signal representative of the temperature of the fluid on the first connecting branch 21 and, as previously mentioned, determines a temperature value thereof. The control unit 50 compares the determined temperature value with the predetermined temperature threshold value: if the temperature value determined by the control unit is lower than the predetermined temperature threshold value, the fluid on the first section 106a of the recirculation line 106 must be heated at least up to reaching a temperature value equal to the predetermined temperature threshold value, in a manner such to allow the fluid on the first section 106a of the recirculation line to be able to serve sanitary hot water to the user. As mentioned above, the control unit 50 is then configured to send the command signal to the pump 17 in order to allow the movement of the fluid through the second chamber 2b of the heat exchange unit, determining the start of the recirculation condition. The control unit 50 is also configured to store a first time instant t1 representative of the start of the recirculation condition, which coincides with the time instant in which the control unit sends the command signal to the pump 17. During the recirculation condition, the hot fluid traversing the first chamber 2a of the heat exchange unit transfers heat to the cold fluid traversing the second chamber 2b of the heat exchange unit, until the sensor 9 detects a temperature value of the fluid on the first section 106a of the recirculation line at least equal to the predetermined temperature threshold value, thus enabling the instantaneous dispensing of sanitary hot water following a request of the user.

[0103] During the passage of the fluid through the first chamber 2a of the heat exchange unit 2 and in the main operating condition of the device 1, the first and the second sensor 12, 13 generate the respective signals representative of the temperature value T1 of the fluid on the first branch 3 and of the temperature value T2 of the fluid on the second connecting branch 20, while the hydraulic device 6' generates the signal representative of the flow rate of the flow traversing the second connecting branch 20. The first and the second temperature sensor 12, 13 and the hydraulic device 6' are then configured to send to the control unit 50 the respective signals of temperature and flow rate generated for determining the temperature values T1 and t2 and flow rate value Q.

[0104] If the temperature value of the fluid on the first section 106a of the recirculation line is at least equal to or greater than the predetermined temperature threshold value, the control unit 50 is configured to send the command signal to the pump 17, which passes from the active condition to the disabled condition, determining the end of the recirculation condition and consequently the passage of the device 1 from the recirculation condition to the main operating condition. In this case, the control unit 50 is configured to store a second time instant t2 representative of the fine of the recirculation condition, which coincides with the time instant in which the control unit sends the command signal to the pump 17 in order to determine the disabling of the latter. The control unit 50 is also configured to calculate the value of instantaneous thermal power and the value of energy E consumed for heating the fluid traversing the second chamber 2b of the heat exchange unit 2 during the recirculation condition, as a function of the following values: the first and the second time instant t1, t2, the temperature value T1 of the fluid on the first branch 3, the temperature value T2 of the fluid on the second connecting branch 20, the flow rate value of the fluid Q.

[0105] In particular, the control unit 50 is configured to calculate and store the value of thermal energy E consumed by means of the following formula: E = ∫ t 1 t 2 CpQ Δ Tdt wherein: E is the thermal energy exchanged by the heat exchange unit, Cp is the specific heat of the fluid, Q is the flow rate value of the fluid calculated as a function of the signal emitted by the hydraulic sensor, ΔT is the value calculated from the difference of the temperature values T2-T1, t1 and t2 are the first and the second time instant.

[0106] The recirculation device 1 can further comprise a display directly connected to the control unit 50 and configured to show the value of thermal energy E calculated by the control unit 50.

[0107] It is noted that this first embodiment allows calculating and storing the value of thermal energy exchanged by the heat exchange unit 2 during the recirculation condition.

[0108] In accordance with the second embodiment of the invention shown in figure 3, the recirculation device can comprise a flow regulator 5 active on the second connecting branch 20 and configured to selectively allow or prevent the passage of fluid along said duct. In particular, the flow regulator 5 can for example be a valve positionable between an open position and a closed position. In the open position the flow regulator 5 allows the passage of the fluid through the first chamber 2a of the heat exchange unit 2, while in the closed position the flow regulator 5 prevents the passage of the fluid through the first chamber 2a of the heat exchange unit 2. The flow regulator 5, in the main operating condition of the recirculation device 1, prevents fluid from passing through the delivery line 104, traversing and heating the first chamber 2a. The flow regulator 5 is also connected to the control unit 50 and configured to receive from the latter an actuation signal adapted to allow the passage of the flow regulator 5 from the open position to the closed position. It is noted that the control unit 50 sends the actuation signal to the flow regulator following the comparison of the temperature value of the fluid on the first connecting section 21. As mentioned above, if the temperature value of the fluid on the first connecting section 21 is lower than the temperature threshold value, then the control unit 50 determines the start of the recirculation condition. In addition to that already described above, in the second embodiment of the recirculation device, the control unit 50 is also configured to send the actuation signal to the flow regulator 5 simultaneously with the determination of the start of the recirculation condition. The flow regulator 5, following the receipt of the actuation signal and in the closed condition, is configured to pass from the closed condition to the open condition, allowing the passage of hot fluid through the first chamber 2a of the heat exchange unit 2. In this manner, the fluid, by means of the first branch 3, traverses the first chamber 2a of the heat exchange unit 2, transferring heat to the fluid traversing the second chamber 2b. Hence it is noted that in the latter embodiment of the invention, the fluid traverses the first chamber of the heat exchange unit only during the recirculation condition, thus preventing a prior heating of the heat exchange unit 2. The control unit 50 is configured to calculate the value of thermal energy exchanged in a manner entirely analogous to that described above.

[0109] As shown in figure 3, the flow regulator 5 can for example be a thermostatic valve, configured to pass from the open position to the closed position as a function of the temperature value of the fluid downstream of the delivery outlet 2a" of the heat exchange unit 2 or as a function of the temperature value of the fluid on the first section 106a, optionally on the second connecting branch 20. Of course it is possible to arrange the flow regulator 5, optionally the thermostatic valve, on the first branch 3 i.e. entering the exchanger.

[0110] The recirculation device could further comprise an auxiliary flow regulator 8 configurable in fluid communication on the first connecting branch 21 or on the first section 106a of the recirculation line, configured to pass from an open condition to a closed condition. In particular, the auxiliary flow regulator 8 can be a thermostatic valve configured to pass from the open condition to the closed condition as a function of a temperature value of the fluid on the first connecting branch 21 or on the first section 106a of the recirculation line. The flow regulator 8 allows, at least during the recirculation condition, reducing the fluid flow rate on the first section 106a of the recirculation line 106 and on the first connecting branch 21.

[0111] In a further embodiment of the invention not shown in the enclosed figures, the recirculation device 1 does not have any temperature sensor set to detect the temperature of the fluid traversing the first section 106a of the recirculation line or of the first connecting branch 21. Indeed, the control unit 50 is configured to periodically send the command signal and / or the actuation signal respectively to the pump 17 and to the flow regulator, in order to allow the variation thereof between the respective operating conditions. In the latter embodiment, the control unit determines the passage from the main operating condition to the recirculation condition and vice versa. Indeed, during design or installation of the recirculation device, it is possible to set the control unit so that the recirculation condition is activated in order to be able to attain the greatest possible energy savings. In particular, it is possible to vary the periodicity of the periodic signal with which the control unit sends the command signal and / or the actuation signal, for example as a function of the hours of the day or of the seasons. Still with reference to the latter embodiment, the calculation of the value of thermal power exchanged by the heat exchange unit occurs according to that described above. In other words, simultaneously with the generation of the command signal, the control unit 50 is configured to receive and store the signals representative of the temperature values on the first branch 3 on the second section 106b of the recirculation line 106 or on the second connecting branch 20, respectively generated by the first and by the second temperature sensor 12, 13, together with the signal representative of the flow rate value generated by the hydraulic device 6'. The control unit 50 is also configured to store the time instants t1 and t2 representative of the duration of the recirculation condition, as well as to calculate the value of thermal energy E exchanged by the heat exchange unit analogous to that described above.System

[0112] Also forming the object of the present invention is a system 100 for distributing sanitary hot water comprising the recirculation device 1 in accordance with the above-described description.

[0113] As is visible from figure 4, the system 100 comprises a heat generator 101, optionally comprising a sanitary hot water storage device and / or a boiler, for heating sanitary water drawn from a water supply network. The system can comprise at least one user 105 for serving sanitary hot water to a system user.

[0114] The system can further comprise a general delivery line 102 for transporting the fluid exiting from the heat generator 101, towards each housing unit / apartment of the multi-family building, as well as a general return line 103 configured to serve the heat generator 101 with the sanitary water exiting from each housing unit. The system can comprise a delivery line 104 which places in fluid communication the general supply line 102 with each user 105. Furthermore, the system 100 comprises at least one recirculation line 106 configured to place in fluid communication each user 105 with the general return line 103. In particular, the recirculation line 106 can comprise at least one first section 106a in fluid communication with the user 105 and the recirculation device, in particular with the recirculation inlet 2b" of the second chamber 2b of the heat exchange unit, and a second section 106b in fluid communication with the general return line 103. The second section 106b of the recirculation line 106 can also be in fluid communication with the recirculation device, in particular with the delivery outlet 2a" of the first chamber 2a of the heat exchange unit 2.

[0115] The system 100 can further comprise a predetermined number of valves for intercepting fluid active on the delivery line 104 or on the first section 106a of the recirculation line 106, each of which configured to section the duct on which it is active in order to facilitate possible system maintenance operations. In particular, the system 100 comprises a first fluid interception valve 16a in fluid communication with the delivery line 104, interposed between the general supply line 102 and the connecting point between the first branch 3 of the recirculation device and the delivery line 104.

[0116] The system can further comprise a first and a second fluid interception valve 16b, 16c, each of which in fluid communication with the first section 106a of the recirculation line 106, respectively immediately upstream and immediately downstream of the user 105. The first and the second valve 16b, 16c consequently prevent the movement of the fluid towards the user 105 from a point of the first section of the recirculation line, upstream of the second valve 16b or downstream of the third valve 16c, sectioning the recirculation device from the user.

Claims

1. A fluid recirculation device (1) installable on a distribution system (100) for sanitary water, said distribution system (100) being of the type comprising: - at least one heat generator (101), optionally a sanitary hot water storage device and / or a boiler, - a general supply line (102) configured to receive the fluid exiting the heat generator (101), - a general outlet line (103) configured to serve fluid to the heat generator (101), - at least one delivery line (104) which puts the general supply line (102) in fluid communication with at least one user (105), - at least one recirculation line (106) which places in fluid communication said user (105) with the general outlet line (103), wherein said recirculation device (1) comprises: - at least one heat exchange unit (2) installable on the recirculation line (106) of the distribution system, said heat exchange unit (2) having at least one first and one second chamber (2a, 2b) distinct from each other, wherein the first chamber (2a) has at least one delivery inlet (2a') and one delivery outlet (2a"), wherein the second chamber (2b) has at least one recirculation inlet (2b') and one recirculation outlet (2b"), wherein the recirculation inlet (2b') of the second chamber (2b) of the heat exchange unit (2) is connectable to a first section (106a) of the recirculation line that places the at least one user (105) in fluid communication with said one heat exchange unit (2), - at least a second branch (4) configured to place the delivery line (104) in fluid communication with the recirculation outlet (2b") of the second chamber (2b) of the heat exchange unit (2), wherein the recirculation device (1) is configured to define a recirculation condition wherein at least part of the fluid passing from the recirculation line (106) traverses the second chamber (2b) of the heat exchange unit (2) characterized in that the delivery outlet (2a") of the first chamber (2a) of said one heat exchange unit (2) is connectable to a second section (106b) of the recirculation line which places in fluid communication said one heat exchange unit (2) with said general fluid outlet (103) and at least one first branch (3) configured to place the delivery line (104) in fluid communication with the delivery inlet (2a') of the first chamber (2a) of the heat exchange unit (2).

2. Device according to claim 1, wherein, in the recirculation condition, at least part of the fluid passing from the delivery line (104) traverses the first chamber (2a) of the heat exchange unit (2), optionally the heat exchange unit (2), in the recirculation condition, is configured to: - receive fluid entering the first chamber (2a) through the delivery inlet (2a'), - eject fluid from the first chamber (2a) through the delivery outlet (2a).

3. Device according to any one of the preceding claims, wherein the heat exchange unit (2) is configured to allow a heat exchange between the fluid circulating in the first chamber (2a) and the fluid present, optionally circulating, in the second chamber (2b), wherein the heat exchange unit (2) comprises at least one heat exchanger, optionally of plate type.

4. Device according to any one of the preceding claims comprising at least one hydraulic sensor (6'), optionally a flowmeter, installable on at least one between the first branch (3) and the second section (106b) of the recirculation line (106), wherein said hydraulic sensor (6') is configured to generate at least one signal relative to at least one parameter representative of a fluid flow, wherein the parameter representative of a fluid flow emitted by the hydraulic sensor (6') comprises at least one of: a fluid flow rate, a fluid velocity, a fluid pressure difference, in which the hydraulic sensor (6') is configured to be installed on the second section (106b) of the recirculation line (106), in proximity to the delivery outlet (2a") of the heat exchange unit (2), or the hydraulic sensor (6') is configured to be installed upstream of the heat exchange unit (2).

5. Device according to any one of the preceding claims comprising: - at least one first temperature sensor (12) installed on the first branch (3) and configured to generate a signal representative of a temperature value of the fluid traversing said first branch (3), - at least one second temperature sensor (13) configured to be installed on the second section (106b) of the recirculation line (106) and configured to generate a signal representative of a temperature value of the fluid traversing said second section (106b).

6. Device according to claim 5 comprising at least one control unit (50) connected to the hydraulic sensor (6'), to the first temperature sensor (12) and to the second temperature sensor (13), said control unit (50) being configured to receive signals from said sensors (6', 12, 13) and to determine, as a function of said signals and at least in the recirculation condition, a value of instantaneous thermal power exchanged by the heat exchange unit (2) in order to determine the energy exchanged in a predetermined time interval.

7. Device according to the preceding claim, wherein the control unit (50), at least in the recirculation condition, is configured to: - receive the signal emitted by the hydraulic sensor (6') and, depending on said signal, determine a value of a fluid flow rate passing through the first branch (3) and / or the second section (106b) of the recirculation line (106), - receive the signal emitted by the first temperature sensor (12) and, depending on said signal, determine a temperature value of the fluid traversing the first branch (3), - receive the signal emitted by the second temperature sensor (13) and, depending on said signal, determine a temperature value of the fluid traversing the second section (106b) of the recirculation line (106), wherein the control unit (50), depending on the determined flow rate and temperature values, is configured to determine the instantaneous thermal power exchanged by the heat exchange unit (2) in order to determine the energy exchanged in a predetermined time interval.

8. Device according to any one of the preceding claims comprising at least one flow regulator (5) in fluid communication with the delivery outlet (2a") of the heat exchange unit (2) and configured to vary the flow rate of the fluid traversing the first chamber (2a) of the heat exchange unit (2), wherein the flow regulator (5) is configurable at least: - an open position wherein it allows fluid to flow through the first chamber (2a) of the heat exchange unit (2) to define the recirculation condition of the recirculation device, - a closed position wherein it prevents the flow of the fluid through the first chamber (2a) of the heat exchange unit (2), the flow regulator (5) can be configured between the open position and the closed position depending on at least one reference parameter including at least one from among: pre-set time intervals, a command signal, a temperature value of the fluid present in the heat exchange unit, a temperature value of the fluid present within the recirculation line.

9. Device according to claim 8, wherein the control unit (50) is directly connected to the flow regulator (5) and configured to send to the latter at least one actuation signal, said flow regulator (5), following the receipt of the actuation signal, being configurable between the open position and the closed position and vice versa.

10. Device according to any one of the preceding claims comprising at least one pump (17) arranged on the first section (106a) of the recirculation line (106), said pump (17) being configured to operate at least between: - an active condition wherein it moves the fluid through the second chamber (2b) of the heat exchange unit (2), and - a disabled condition wherein the pump (17) does not move the fluid, in which the pump (17) operates in the active condition at least in the recirculation condition of the recirculation device (1), wherein the control unit (50) is connected to and activated in command of said pump (17), wherein the control unit is configured to activate the pump (17) depending on at least one reference parameter including at least one selected in the group of: the fluid temperature on the second section of the recirculation line (106), the fluid temperature on the first section of the recirculation line (106), predetermined time intervals.

11. Device according to any one of the preceding claims comprising at least one auxiliary temperature sensor (9) in fluid communication with the first section (106a) of the recirculation line (106), configured to generate a signal representative of a fluid temperature on the first section (106a) of the recirculation line (106), wherein the auxiliary temperature sensor (9) is connected to the control unit (50), said auxiliary temperature sensor (9) being configured to send to the control unit (50) a signal representative of the fluid temperature on the first section (106a) of the recirculation line (106), optionally on the / a first connecting branch (21), the control unit (50), following receipt of the signal representative of the fluid temperature on the first section (106a) of the recirculation line (106), optionally on the first connecting branch (21), is configured to: - determine a fluid temperature value on the first section (106a) of the recirculation line (106), - compare said value with a predetermined threshold value, optionally equal to 28°C, the control unit, if the temperature value determined by the control unit is lower than the predetermined threshold value, being configured to determine the start of the recirculation condition.

12. Device according to the preceding claim, wherein, in the recirculation condition, the control unit (50) is configured to: - send an actuation signal to the flow regulator (5), allowing it to switch between the closed and open positions, - send a command signal to the pump (17) allowing it to switch from the disabled condition to the active condition, - store a first time instant (t1) at which the control unit (50) sends the command signal or the actuation signal, - receive from the first sensor the temperature signal representative of the temperature value on the first branch (3), - receive from the second sensor the temperature signal representative of the temperature value on the second section (106b) of the recirculation line (106).

13. A fluid distribution system comprising: - at least one heat generator (101), - a general supply line (102) configured to distribute the fluid exiting the heat generator (101), - a general outlet line (103) configured to serve return fluid to the heat generator (101), - at least one delivery line (104) which connects the general supply line (102) to at least one user (105), - at least one recirculation line (106) which places in fluid communication said at least one user (105) with the general outlet line (103), - a recirculation device (1) according to any one of the preceding claims, wherein the first section (106a) of the recirculation line (106) is connected to the recirculation inlet (2b') of the heat exchange unit (2) and the second section (106b) of the recirculation line (106) is connected to the delivery outlet (2a") of the heat exchange unit (2).

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