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EP-4423434-B1 - FLUID RECIRCULATION DEVICE, DISTRIBUTION SYSTEM FOR SANITARY WATER USING SAID DEVICE

EP4423434B1EP 4423434 B1EP4423434 B1EP 4423434B1EP-4423434-B1

Inventors

  • BERTOLOTTI, UMBERTO
  • PEDROTTI, Cristian

Dates

Publication Date
20260513
Application Date
20221014

Claims (13)

  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).

Description

FIELD OF THE FINDING 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 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. 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. 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. 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. 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. Some known solutions of a hydraulic system for distributing sanitary hot water to a series of users are exemplified in the following documents. 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. 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. 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. Document US 4 936 289 A concerns an energy conservation apparatus for controlling the operation of a recirculating hot water distribution system which compr