JP2020046143A - Feedwater heating system - Google Patents

Abstract

To provide a feedwater heating system that can efficiently recover heat from heat source water.SOLUTION: A feedwater heating system comprises a feedwater tank 2, a heat source water tank 3, first to third feedwater lines 11, 12, and 13 for supplying feedwater CW to the feedwater tank 2, first and second heat source water lines 21 and 22 for sending heat source water SW from the heat source water tank 3, a first heat exchanger 31 for heating the feedwater CW flowing through the first feedwater line 11 by exchanging heat with the heat source water SW flowing through the first heat source water line 21, a second heat exchanger 32 for heating the feedwater CW flowing through the second feedwater line 12 by exchanging heat with the heat source water SW flowing through the second heat source water line 22, a fourth feedwater line 14 for connecting the first feedwater line 11 downstream of the first heat exchanger 31 and the second feedwater line 12 upstream of the second heat exchanger 32, valves 41-44 for switching a flow passage for the feedwater to a predetermined mode, and a control device 50 for controlling the valves 41-44.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a feedwater heating system.

  There has been proposed a technique of heating feed water using waste hot water discharged from a factory or the like as a heat source water and supplying the heated feed water to a feed tank of a boiler. By supplying warmed water to the boiler from the water supply tank, the fuel required to generate steam in the boiler is reduced. Patent Literature 1 discloses a feedwater heating system in which heat is drawn from heat source water by a heat pump to heat feedwater.

JP 2013-210118 A

  Since the coefficient of performance (COP) improves as the temperature difference between the high-temperature part and the low-temperature part becomes smaller, the heat pump changes the temperature of the supply water on the low-temperature part side (normal temperature of 10 to 30 ° C.) to the heat source water on the high-temperature part side. The closer the temperature, the higher the heat recovery efficiency. On the other hand, when the temperature of the heat source water is too high, the heat recovery efficiency of the heat pump is reduced. The temperature of waste hot water discharged from factories and the like varies depending on the type of business, and there are various patterns in the temperature change of waste hot water during operation. Therefore, when the temperature of the heat source water is high, it is more advantageous to simply recover the heat using only the heat exchanger.Therefore, a technology that can efficiently recover heat from the heat source water even in a system using only the heat exchanger is advantageous. Requested.

  An object of the present invention is to provide a feedwater heating system capable of efficiently recovering heat from heat source water.

  According to an aspect of the present invention, a water supply tank for storing water supply, a heat source water tank for storing heat source water, a first water supply line for supplying water to the water supply tank, and a water supply to the water supply tank. A second water supply line, a third water supply line for supplying water to the water supply tank, a first heat source water line for supplying heat source water from the heat source water tank, and a second water supply line for supplying heat source water from the heat source water tank. Heat exchange between the heat source water line and the heat source water flowing through the first heat source water line heats the feedwater flowing through the first water supply line, and flows through the second heat source water line. A second heat exchanger for heating the feedwater flowing through the second feedwater line by heat exchange with the heat source water to be heated, and the first heat exchanger downstream of the first heat exchanger and the second heat exchange. The second water supply line upstream of the vessel A water supply line, wherein a flow passage switching means for switching the water supply flow path in a predetermined mode for the water supply tank, water heating system comprising a control means, a for controlling the flow path switching means.

  According to an aspect of the present invention, there is provided a feedwater heating system capable of efficiently recovering heat from heat source water.

Drawing 1 is a mimetic diagram showing an example of a water supply warming system concerning an embodiment. FIG. 2 is a functional block diagram illustrating an example of the control device according to the embodiment. Drawing 3 is a figure for explaining an example of the control method of the feed water heating system concerning an embodiment. Drawing 4 is a figure for explaining an example of operation of the water supply warming system concerning an embodiment. FIG. 5 is a diagram for explaining an example of the operation of the feedwater heating system according to the embodiment. Drawing 6 is a figure for explaining an example of operation of the water supply warming system concerning an embodiment. Drawing 7 is a figure for explaining an example of operation of the water supply warming system concerning an embodiment. FIG. 8 is a block diagram illustrating an example of the computer system according to the embodiment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The components of the embodiments described below can be appropriately combined. In some cases, some components may not be used.

[Water supply heating system]
FIG. 1 is a diagram schematically illustrating an example of a feedwater heating system 1 according to the present embodiment. The feed water heating system 1 is provided in an industrial facility such as a factory. The feedwater heating system 1 heats the feedwater CW using the heat of the heat source water SW, and supplies the heated feedwater CW to the feedwater tank 2 of the boiler 80. The heat source water SW includes waste hot water discharged from the industrial facility.

  The feed water heating system 1 includes a feed water tank 2 that stores feed water CW, a heat source water tank 3 that stores heat source water SW, a first feed line 11 that feeds feed water CW to the feed water tank 2, and a feed water CW that feeds feed water CW. A second water supply line 12 for supplying water to the tank 2, a third water supply line 13 for supplying water CW to the water supply tank 2, a first heat source water line 21 for supplying heat source water SW from the heat source water tank 3, and a heat source Heat exchange between the second heat source water line 22 that sends out the water SW from the heat source water tank 3 and the heat source water SW flowing through the first heat source water line 21 heats the feed water CW flowing through the first water supply line 11. Heat exchange between the first heat exchanger 31 and the heat source water SW flowing through the second heat source water line 22 to heat the feedwater CW flowing through the second water supply line 12; The first water supply line downstream of the heat exchanger 31 Comprising 11 and the fourth water supply line 14 which connects the second water supply line 12 on the upstream side of the second heat exchanger 32.

  In addition, the feed water heating system 1 includes a raw water line 15 that feeds the feed water CW to the first feed line 11, the second feed line 12, and the third feed line 13, a first feed line 11, and a second feed line 12. , And a hot water line 16 that feeds water CW that has passed through at least one of the third water supply lines 13 to the water supply tank 2.

  Further, the feed water heating system 1 has a first valve 41 that can switch between the flow of the feed water CW from the raw water line 15 to the first feed water line 11 and the flow of the feed water CW from the raw water line 15 to the third feed water line 13. A second valve 42 capable of switching the flow of water CW in the first water supply line 11; a third valve 43 capable of switching the flow of water CW in the second water supply line 12; And a fourth valve 44 capable of switching the flow of the feed water CW in the flow path 11 and the flow of the feed water CW from the first feed water line 11 to the fourth feed water line 14.

  Further, the feed water heating system 1 is connected to a raw water line 15, a water level sensor 4 for detecting a water level L of the feed water tank 2, a temperature sensor 5 for detecting a temperature T of the feed water CW supplied to the feed water tank 2. A water treatment device 6, a pressure sensor 7 for detecting a back pressure P of the water treatment device 6, and a flow rate adjusting device 8 for adjusting a flow rate Q of water flowing through the water treatment device 6.

  Further, the feedwater heating system 1 includes a control device 50. The control device 50 controls the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44.

<Boiler>
Boiler 80 is a steam boiler. The boiler 80 generates steam by heating the feedwater CW supplied from the feedwater tank 2. The water supply tank 2 and the boiler 80 are connected via a hot water line 81. A hot water pump 82 is provided in the hot water line 81. By driving the hot water pump 82, the feedwater CW stored in the feedwater tank 2 is supplied to the boiler 80. The steam generated by the boiler 80 is supplied to a steam-using device (not shown). By supplying the heated feedwater CW from the feedwater tank 2 to the boiler 80, the fuel required for generating steam in the boiler 80 is reduced.

<Tank>
The water supply tank 2 stores the water supply CW sent from the raw water line 15 and having passed through at least one of the first water supply line 11, the second water supply line 12, and the third water supply line 13.

  The heat source water tank 3 stores the heat source water SW supplied to the first heat exchanger 31 and the second heat exchanger 32. The heat source water SW is supplied from the industrial facility to the heat source water tank 3 via the supply line 9. The heat source water tank 3 has an overflow path 10 for causing the heat source water SW to overflow.

<Raw water line>
The raw water line 15 supplies the water CW supplied from a water supply source (not shown) to the first water supply line 11, the second water supply line 12, and the third water supply line 13. The feedwater CW sent from the raw water line 15 is the feedwater CW before heating. The temperature of the feedwater CW sent from the raw water line 15 is, for example, 20 ° C.

  The water treatment device 6 processes the feedwater CW supplied to the first water supply line 11, the second water supply line 12, and the third water supply line 13. The water treatment device 6 includes a deoxygenation device that removes dissolved oxygen from the feedwater CW.

  The flow control device 8 functions as a flow control device that controls the flow rate Q of the water flowing through the water treatment device 6. Examples of the flow control device 8 include, for example, at least one of a flow control valve disposed in the raw water line 15 and a feed pump controlled by an inverter.

<Water supply line>
The first water supply line 11, the second water supply line 12, and the third water supply line 13 are arranged in parallel. The first water supply line 11 has an upstream end 11A and a downstream end 11B. The second water supply line 12 has an upstream end 12A and a downstream end 12B. The third water supply line 13 has an upstream end 13A and a downstream end 13B. The fourth water supply line 14 has an upstream end 14A and a downstream end 14B.

  The downstream end 15B of the raw water line 15 is connected to the upstream end 11A of the first water supply line 11 and the upstream end 13A of the third water supply line 13 via the first valve 41. An upstream end 16A of the hot water line 16 is connected to a downstream end 11B of the first water supply line 11 and a downstream end 13B of the third water supply line 13.

  At least a part of the first water supply line 11 is arranged in the first heat exchanger 31.

  An upstream end 12A of the second water supply line 12 is connected to an intermediate portion 11C of the first water supply line 11 between the upstream end 11A and the first heat exchanger 31. The downstream end 12B of the second water supply line 12 is connected to an intermediate portion 11D of the first water supply line 11 between the first heat exchanger 31 and the downstream end 11B.

  At least a part of the second water supply line 12 is arranged in the second heat exchanger 32.

  The upstream end 14A of the fourth water supply line 14 is connected to the first water supply line 11 between the first heat exchanger 31 and the intermediate portion 11D via the fourth valve 44. The downstream end 14B of the fourth water supply line 14 is connected to the second water supply line 12 between the upstream end 12A and the second heat exchanger 32.

<Heat source water line>
The first heat source water line 21 and the second heat source water line 22 are arranged in parallel. The first heat source water line 21 has an upstream end 21A. The second heat source water line 22 has an upstream end 22A and a downstream end 22B.

  The upstream end 21 </ b> A of the first heat source water line 21 is connected to the heat source water tank 3.

  At least a part of the first heat source water line 21 is disposed in the first heat exchanger 31.

  The upstream end 22A of the second heat source water line 22 is connected to an intermediate portion 21C of the first heat source water line 21 between the upstream end 21A and the first heat exchanger 31. The downstream end 22B of the second heat source water line 22 is connected to the intermediate portion 21D of the first heat source water line 21 downstream of the first heat exchanger 31.

  At least a part of the second heat source water line 22 is disposed in the second heat exchanger 32.

<Valve>
The first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 function as flow path switching means for switching the flow path of the feedwater CW to the feedwater tank 2 to a predetermined mode.

  The first valve 41 is a three-way valve connected to each of the downstream end 15B of the raw water line 15, the upstream end 11A of the first water supply line 11, and the upstream end 13A of the third water supply line 13. The first valve 41 circulates the feedwater CW supplied from the raw water line 15 to the first water supply line 11 and does not flow to the third water supply line 13, and sets the supply water CW supplied from the raw water line 15 to the third water supply. It is possible to switch from one to the other between a state in which the gas flows through the line 13 and a state in which it does not flow through the first water supply line 11.

  The second valve 42 is a two-way valve arranged in the first water supply line 11 between the intermediate portion 11C and the first heat exchanger 31. The second valve 42 is switchable from one state to the other state between a state in which the water supply CW supplied from the upstream end 11 </ b> A flows through the first water supply line 11 and a state in which the water supply CW does not flow through the first water supply line 11.

  The third valve 43 is a two-way valve arranged in the second water supply line 12 between the upstream end 12A and the second heat exchanger 32. The third valve 43 is switchable from one state to the other state between a state in which the water supply CW supplied from the upstream end 12A flows through the second water supply line 12 and a state in which the water supply CW does not flow through the second water supply line 12.

  The fourth valve 44 has an outflow end 11E in the first water supply line 11 where the water CW from the first heat exchanger 31 flows out, and an inflow end in the first water supply line 11 into which the water CW supplied to the downstream end 11B flows. 11F and a three-way valve connected to each of the upstream end 14A of the fourth water supply line 14. The fourth valve 44 allows the feedwater CW flowing out of the first heat exchanger 31 to flow through the first feedwater line 11 and not flow through the fourth feedwater line 14, and the feedwater CW flowing out of the first heat exchanger 31. Can be switched from one to the other in a state in which is flowed through the fourth water supply line 14 and not flown through the first water supply line 11.

<Heat exchanger>
The first heat exchanger 31 heats the feed water CW by heat exchange between the feed water CW flowing through the first feed water line 11 and the heat source water SW flowing through the first heat source water line 21. The feedwater CW heated by the first heat exchanger 31 is supplied to the fourth valve 44.

  The second heat exchanger 32 heats the feed water CW by exchanging heat between the feed water CW flowing through the second feed water line 12 and the heat source water SW flowing through the second heat source water line 22. The feedwater CW heated by the second heat exchanger 32 is supplied to the hot water line 16 via a part of the first feedwater line 11.

  Each of the first heat exchanger 31 and the second heat exchanger 32 may be a shell-and-tube heat exchanger or a laminated plate heat exchanger.

<Sensor>
The water level sensor 4 functions as a water level detection unit that detects the water level L of the water supply tank 2. The water level L of the water supply tank 2 refers to the height of the surface of the water supply CW stored in the water supply tank 2. The water level sensor 4 is provided in the water supply tank 2. The water level sensor 4 includes an electrode type water level sensor. A plurality of electrode rods may be arranged in the water supply tank 2 as the water level sensor 4. The plurality of electrode rods are arranged in the water supply tank 2 such that the lower ends of the electrode rods have different heights. The water level L of the water supply tank 2 is detected by specifying the electrode rod in contact with the water supply CW. The water level sensor 4 only needs to be able to detect the water level L of the water supply tank 2, and may use a capacitance type water level sensor or a pressure type sensor other than the electrode type water level sensor.

  Temperature sensor 5 detects temperature T of feedwater CW supplied to feedwater tank 2. The temperature sensor 5 is provided in the hot water line 16. Temperature sensor 5 detects temperature T of feedwater CW flowing through hot water line 16.

  The pressure sensor 7 functions as pressure detecting means for detecting the back pressure P of the water treatment device 6. The back pressure P of the water treatment device 6 indicates the pressure at the outlet of the water treatment device 6 at which the feedwater CW treated in the water treatment device 6 flows out. The pressure sensor 7 is provided in the raw water line 15 through which the feedwater CW flowing out of the outlet of the water treatment device 6 flows, and detects the back pressure P of the water treatment device 6.

  The control device 50 functions as control means for controlling the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44.

  FIG. 2 is a functional block diagram illustrating an example of the control device 50 according to the present embodiment. As shown in FIG. 2, the control device 50 includes a detection water level acquisition unit 51, a detection temperature acquisition unit 52, a detection pressure acquisition unit 53, a flow command unit 54, a mode determination unit 55, a control command And an output unit 56.

  The detected water level acquisition unit 51 acquires a detected water level value indicating the detection value of the water level sensor 4. The detected water level value indicates the water level L of the water supply tank 2.

  The detected temperature value acquiring section 52 acquires a detected temperature value indicating a detected value of the temperature sensor 5. The detected temperature value indicates the temperature T of the feedwater CW supplied to the feedwater tank 2.

  The detected pressure value acquiring section 53 acquires a detected pressure value indicating a detected value of the pressure sensor 7. The detected pressure value indicates the back pressure P of the water treatment device 6.

  The flow command unit 54 outputs a flow command for controlling the flow control device 8 based on the water level value detected by the water level sensor 4. The flow command unit 54 stores a water level threshold value relating to the water level L of the water supply tank 2. The water level threshold is lower than the low water level threshold LL, the first middle water level threshold LM1 higher than the low water level threshold LL, the second middle water level threshold LM2 higher than the first middle water level threshold LM1, and the second middle water level threshold LM2. And a high high water level threshold LH (LL <LM1 <LM2 <LH). When the detected water level value of the water level sensor 4 falls below the low water level threshold value LL, the flow rate command unit 54 controls the flow rate adjusting device 8 such that the flow rate Q of the water in the water treatment device 6 becomes the first flow rate Qmax. When the detected water level value of the water level sensor 4 exceeds the first middle water level threshold LM1, the flow rate command unit 54 sets the flow rate Q of the water treatment device 6 to the second flow rate Qmid smaller than the first flow rate Qmax. The flow control device 8 is controlled. When the detected water level value of the water level sensor 4 exceeds the high water level threshold LH, the flow rate command unit 54 adjusts the flow rate so that the flow rate Q of the water in the water treatment device 6 becomes the third flow rate Qmin smaller than the second flow rate Qmid. The device 8 is controlled. The first flow rate Qmax is, for example, the maximum flow rate (100% flow rate) through which the water treatment device 6 can flow water. The second flow rate Qmid is, for example, a half value of the maximum flow rate or an approximate value of a half value of the maximum flow rate (50 to 60% flow rate). The third flow rate Qmin includes that the water flow rate Q is zero (0% flow rate).

  The mode determining unit 55 determines at least one of the detected water level value of the water level sensor 4, the detected temperature value of the temperature sensor 5, the detected water level value of the pressure sensor 7, and the flow rate command for controlling the flow rate Q of the water treatment device 6. Accordingly, the mode related to the flow path of the feedwater CW to the feedwater tank 2 is determined.

  The control command output unit 56 outputs a control command for controlling the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 based on the mode determined by the mode determining unit 55.

  Note that the detected water level value acquisition unit 51 and the flow rate command unit 54 may be configured to be mounted on a local control device (not shown) of the water treatment device 6. When the flow controller 8 is controlled by the local controller of the water treatment device 6, the mode determining unit 55 acquires information on the flow command output from the flow command unit of the local controller.

[mode]
Next, the operation of the feed water heating system 1 according to the present embodiment will be described. 3 to 7 are diagrams for explaining an example of the operation of the feed water heating system 1 according to the present embodiment. 3 to 7 schematically show modes relating to the flow path of the feedwater CW to the feedwater tank 2. FIG. 3 to 7, illustration of the first heat source water line 21 and the second heat source water line 22 is omitted.

<First hot water supply mode (series water supply mode)>
FIG. 3 is a diagram illustrating the first hot water supply mode. In the first hot water supply mode, the feed water CW from the raw water line 15 is sent to the first heat exchanger 31, and the feed water CW after passing through the first heat exchanger 31 is sent to the second heat exchanger 32. It is a serial water supply mode.

  As shown in FIG. 3, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 block the flow of the water CW in the third water supply line 13, and the first water supply line 11, The first hot water supply mode (series water supply mode) in which the water CW flows in the order of the four water supply lines 14 and the second water supply line 12 can be set.

  When setting the flow path of the feedwater CW to the feedwater tank 2 to the first hot water supply mode, the control command output unit 56 cuts off the flow of the feedwater CW from the raw water line 15 to the third feedwater line 13, and The first valve 41 is controlled so that the water CW flows through the one water supply line 11. In addition, the control command output unit 56 controls the second valve 42 so that the feedwater CW flows from the upstream end 11A to the first heat exchanger 31. Further, the control command output unit 56 controls the third valve 43 so as to cut off the flow of the water CW from the upstream end 12A to the second heat exchanger 32. Further, the control command output unit 56 shuts off the flow of the feedwater CW from the first heat exchanger 31 to the intermediate unit 11D, and causes the feedwater CW to flow from the first heat exchanger 31 to the second heat exchanger 32. , The fourth valve 44 is controlled.

  In the first hot water supply mode, the feedwater CW flowing from the raw water line 15 to the first feedwater line 11 via the first valve 41 flows through the first feedwater line 11 and passes through the first heat exchanger 31. In the first heat exchanger 31, the feedwater CW is heated by heat exchange with the heat source water SW. The feed water CW heated in the first heat exchanger 31 flows into the fourth feed line 14 via the fourth valve 44. The feedwater CW flowing into the fourth feedwater line 14 flows through the second feedwater line 12 and passes through the second heat exchanger 32. In the second heat exchanger 32, the feedwater CW is further heated by heat exchange with the heat source water SW. The feedwater CW heated in the second heat exchanger 32 flows through the second feedwater line 12, passes through the downstream end 12B of the second feedwater line 12 and the downstream end 11B of the first feedwater line 11, and passes through the hot water line. Flow into 16. The feedwater CW flows through the hot water line 16 and is supplied to the feedwater tank 2.

<Second hot water supply mode (parallel water supply mode)>
FIG. 4 is a diagram showing the second hot water supply mode. In the second hot water supply mode, the feedwater CW from the raw water line 15 is supplied to the first heat exchanger 31 and the feedwater CW from the raw water line 15 is supplied in parallel with the supply of the feedwater CW to the first heat exchanger 31. This is a parallel water supply mode in which the water is supplied to the second heat exchanger 32.

  As shown in FIG. 4, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 block the flow of the water CW in the third water supply line 13 and the fourth water supply line 14. A second hot water supply mode (parallel water supply mode) in which the water CW flows in parallel with the first water supply line 11 and the second water supply line 12 can be set.

  When setting the flow path of the feedwater CW to the feedwater tank 2 to the second hot water supply mode, the control command output unit 56 cuts off the flow of the feedwater CW from the raw water line 15 to the third feedwater line 13, and The first valve 41 is controlled so that the water CW flows through the one water supply line 11. In addition, the control command output unit 56 controls the second valve 42 so that the feedwater CW flows from the upstream end 11A to the first heat exchanger 31. Further, the control command output unit 56 controls the third valve 43 so that the feedwater CW flows from the upstream end 12A to the second heat exchanger 32. Further, the control command output unit 56 causes the feedwater CW to flow from the first heat exchanger 31 to the intermediate unit 11D, and cuts off the flow of the feedwater CW from the first heat exchanger 31 to the second heat exchanger 32. , The fourth valve 44 is controlled.

  In the second hot water supply mode, part of the feedwater CW flowing from the raw water line 15 to the first feedwater line 11 via the first valve 41 flows through the first feedwater line 11 and passes through the first heat exchanger 31. I do. In the first heat exchanger 31, the feedwater CW is heated by heat exchange with the heat source water SW. The feedwater CW heated in the first heat exchanger 31 flows through the first feedwater line 11 via the fourth valve 44 and flows into the hot water line 16 via the downstream end 11B of the first feedwater line 11. I do. The water supply CW flows through the hot water line 16 and is supplied to the water supply tank 2. On the other hand, the remainder of the feedwater CW that has flowed into the first feedwater line 11 from the raw water line 15 via the first valve 41 flows into the second feedwater line 12 from the upstream end 12A, and then passes through the second heat exchanger 32. . In the second heat exchanger 32, the feedwater CW is heated by heat exchange with the heat source water SW. The feedwater CW heated in the second heat exchanger 32 flows through the second feedwater line 12, passes through the downstream end 12B of the second feedwater line 12 and the downstream end 11B of the first feedwater line 11, and passes through the hot water line. Flow into 16. The water supply CW flows through the hot water line 16 and is supplied to the water supply tank 2.

<Cold water supply mode>
FIG. 5 is a diagram illustrating the cold water supply mode. The cold water supply mode is a mode in which the feedwater CW from the raw water line 15 is sent to the feedwater tank 2 without being sent to the first heat exchanger 31 and the second heat exchanger 32.

  As shown in FIG. 5, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 are configured to supply water CW of the first water supply line 11, the second water supply line 12, and the fourth water supply line 14. Can be switched to a cold water supply mode in which the water supply CW flows only through the third water supply line 13.

  When setting the flow path of the feedwater CW to the feedwater tank 2 to the cold water supply mode, the control command output unit 56 cuts off the flow of the feedwater CW from the raw water line 15 to the first feedwater line 11, and the third feedwater from the raw water line 15. The first valve 41 is controlled so that the feedwater CW flows through the line 13.

  In the chilled water supply mode, the feedwater CW flowing from the raw water line 15 to the third feedwater line 13 via the first valve 41 flows through the third feedwater line 13, and the first heat exchanger 31 and the second heat exchanger 32 And flows into the hot water line 16 via the downstream end 13B of the third water supply line 13 without passing through. The feedwater CW flows through the hot water line 16 and is supplied to the feedwater tank 2.

<Third hot water supply mode>
FIG. 6 is a diagram showing the third hot water supply mode. The third hot water supply mode is a mode in which feedwater CW from the raw water line 15 is sent to the first heat exchanger 31 and not sent to the second heat exchanger 32.

  As shown in FIG. 6, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 are configured to supply water CW of the second water supply line 12, the third water supply line 13, and the fourth water supply line 14. Can be switched to the third hot water supply mode in which the supply water CW is distributed only to the first water supply line 11.

  When setting the flow path of the feedwater CW to the feedwater tank 2 to the third hot water supply mode, the control command output unit 56 cuts off the flow of the feedwater CW from the raw water line 15 to the third feedwater line 13, and The first valve 41 is controlled so that the water CW flows through the one water supply line 11. In addition, the control command output unit 56 controls the second valve 42 so that the feedwater CW flows from the upstream end 11A to the first heat exchanger 31. Further, the control command output unit 56 controls the third valve 43 so as to cut off the flow of the water CW from the upstream end 12A to the second heat exchanger 32. In addition, the control command output unit 56 shuts off the flow of the feedwater CW from the first heat exchanger 31 to the fourth feedwater line 14 and causes the feedwater CW to flow from the first heat exchanger 31 to the first feedwater line 11. Next, the fourth valve 44 is controlled.

  In the third hot water supply mode, the feedwater CW flowing from the raw water line 15 into the first feedwater line 11 via the first valve 41 flows through the first feedwater line 11 and passes through the first heat exchanger 31. In the first heat exchanger 31, the feedwater CW is heated by heat exchange with the heat source water SW. The feedwater CW heated in the first heat exchanger 31 flows into the first feedwater line 11 via the fourth valve 44. The feedwater CW flowing through the first water supply line 11 flows into the hot water line 16 via the downstream end 11B of the first water supply line 11. The feedwater CW flows through the hot water line 16 and is supplied to the feedwater tank 2.

<Fourth hot water supply mode>
FIG. 7 is a diagram showing a fourth hot water supply mode. The fourth hot water supply mode is a mode in which the feed water CW from the raw water line 15 is sent to the second heat exchanger 32 and not sent to the first heat exchanger 31.

  As shown in FIG. 7, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 supply water CW of the first water supply line 11, the third water supply line 13, and the fourth water supply line 14. Can be switched to the fourth hot water supply mode in which the feedwater CW is passed only through the second feedwater line 12.

  When the flow path of the feedwater CW to the feedwater tank 2 is set to the fourth hot water supply mode, the control command output unit 56 cuts off the flow of the feedwater CW from the raw water line 15 to the third feedwater line 13, and The first valve 41 is controlled so that the water CW flows through the one water supply line 11. Further, the control command output unit 56 controls the second valve 42 so as to block the flow of the feedwater CW from the upstream end 11A to the first heat exchanger 31. Further, the control command output unit 56 controls the third valve 43 so that the feedwater CW flows from the upstream end 12A to the second heat exchanger 32. Further, the control command output unit 56 controls the fourth valve 44 so as to cut off the flow of the feedwater CW from the second feedwater line 12 to the first heat exchanger 31.

  In the fourth hot water supply mode, the feedwater CW flowing from the raw water line 15 to the first feedwater line 11 via the first valve 41 flows into the second feedwater line 12 via the upstream end 12A of the second feedwater line 12. After that, it flows through the second water supply line 12. The feedwater CW passes through the second heat exchanger 32. In the second heat exchanger 32, the feedwater CW is heated by heat exchange with the heat source water SW. The feedwater CW heated in the second heat exchanger 32 flows into the hot water line 16 via the downstream end 12B of the second feedwater line 12 and the downstream end 11B of the first feedwater line 11. The feedwater CW flows through the hot water line 16 and is supplied to the feedwater tank 2.

  As described with reference to FIGS. 3 to 7, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 include a first hot water supply mode, a second hot water supply mode, It is configured to be switchable between a cold water supply mode, a third hot water supply mode, and a fourth hot water supply mode.

[Mode switching method]
<Common items>
When the operation switch of the feed water heating system 1 is turned off, the mode determining unit 55 determines the flow path mode to be the cold water supply mode. The control command output unit 56 controls each of the valves 41 to 44 to shift from the current channel mode to the cold water supply mode. As a result, while the operation of the feed water heating system 1 is stopped, the system enters a standby state in the chilled water supply mode. When the operation switch is turned on, the operation is started from the chilled water supply mode.

<First form>
Next, a first mode of the mode switching method will be described. In the first embodiment, the control device 50 controls the valves 41 to 44 so that the flow path of the feed water CW to the feed water tank 2 is switched to a predetermined mode in accordance with the pressure detected by the pressure sensor 7.

  In the first embodiment, the mode determination section 55 determines a mode based on the pressure value detected by the pressure sensor 7. The mode determining unit 55 stores a pressure threshold value related to the back pressure P of the water treatment device 6. The pressure threshold includes a low pressure threshold PL and a high pressure threshold PH higher than the low pressure threshold PL. The high pressure threshold PH is a value set as an allowable pressure of the water treatment membrane and the mechanical components used in the water treatment device 6, and is a predetermined safety factor (for example, a critical pressure with respect to a critical pressure at which failure or breakage of the device occurs). , 0.7 to 0.9).

  First, in the chilled water supply mode after the activation of the feed water heating system 1, the mode determining unit 55 acquires the detected pressure value of the pressure sensor 7. Specifically, the detected pressure value when the flow command is output so that the flow rate Q of the water in the water treatment device 6 becomes the first flow rate Qmax (100% flow rate) is acquired.

  When the detected pressure value of the pressure sensor 7 exceeds the high pressure threshold PH at the time of outputting the flow rate command in the chilled water supply mode, the mode determination unit 55 determines the flow path mode to be the chilled water supply mode. The control command output unit 56 controls each of the valves 41 to 44 so as to maintain the flow path mode in the cold water supply mode. The chilled water supply mode is a flow path mode in which the back pressure P of the water treatment device 6 can be minimized because the feedwater CW is bypassed for both the first heat exchanger 31 and the second heat exchanger 32. . Therefore, when the back pressure P exceeding the high pressure threshold PH is applied to the water treatment device 6 during the flow command output in the chilled water supply mode, the flow channel mode is set to the chilled water mode in order to prevent the device from being broken or damaged. The feedwater CW in a non-heated state is supplied to the feedwater tank 2 without changing from the supply mode.

  When the detected pressure value of the pressure sensor 7 is lower than the high pressure threshold PH and is between the low pressure threshold PL and the high pressure threshold PH when the flow rate command is output in the chilled water supply mode, the mode determining unit 55 In the second hot water supply mode (parallel water supply mode). The control command output unit 56 controls each of the valves 41 to 44 so as to shift the flow path mode from the cold water supply mode to the second hot water supply mode. In the second hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than that in the cold water supply mode because the feedwater CW flows through both the first heat exchanger 31 and the second heat exchanger 32 in parallel. Is a flow channel mode that can be suppressed lower than the first hot water supply mode. Therefore, when the back pressure P exceeding the high pressure threshold PH is not applied to the water treatment device 6 at the time of outputting the flow rate command in the chilled water supply mode, there is no possibility that the device will fail or be damaged. The mode is changed to the two hot water supply mode, and the feedwater CW individually heated in the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feedwater tank 2.

  When the detected pressure value of the pressure sensor 7 is lower than the low pressure threshold PL at the time of outputting the flow rate command in the cold water supply mode, the mode determination unit 55 determines the flow path mode to be the first hot water supply mode (series water supply mode). I do. The control command output unit 56 controls each of the valves 41 to 44 so as to shift the flow path mode from the cold water supply mode to the first hot water supply mode. In the first hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than in the second hot water supply mode because the feedwater CW flows in series to the first heat exchanger 31 and the second heat exchanger 32. This is the flow channel mode. For this reason, when the flow pressure command is output in the chilled water supply mode, if the back pressure P has a sufficient margin with respect to the high pressure threshold PH, there is no danger of device failure or breakage. The mode is changed to the one hot water supply mode, and the feedwater CW heated in two stages by the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feedwater tank 2.

  After the flow path mode is determined by the mode determination unit 55, the change of the flow path mode may be prohibited, or the change of the flow path mode may be periodically confirmed. In the former case, when the operation switch is turned off, the mode shifts to the chilled water supply mode. Therefore, the back pressure P is checked at the next timing when the operation switch is turned on, and the flow path mode corresponding to the back pressure P is checked. To change. In the latter case, the flow is temporarily shifted to the chilled water supply mode at an arbitrary timing when the flow rate command is output so that the flow rate Q of the water in the water treatment device 6 becomes the first flow rate Qmax (100% flow rate). After confirming the back pressure P, the mode is changed to the flow path mode corresponding to the back pressure P.

<Second embodiment>
Next, a second mode of the mode switching method will be described. In the second embodiment, the control device 50 controls the valves 41 to 44 so that the flow path of the feedwater CW to the feedwater tank 2 is switched to a predetermined mode according to the water level value detected by the water level sensor 4.

  In the second embodiment, the mode determination unit 55 determines a mode based on the pressure value detected by the water level sensor 4. The mode determining unit 55 stores a water level threshold value related to the water level L of the water supply tank 2. The water level threshold includes the low water level threshold LL, the first middle water level threshold LM1, the second middle water level threshold LM2, and the high water level threshold LH described above.

  When the detected water level value of the water level sensor 4 falls below the low water level threshold value LL, the mode determining unit 55 determines the flow path mode to be the cold water supply mode. The control command output unit 56 controls the valves 41 to 44 so as to shift the flow path mode from the first hot water supply mode (series water supply mode) to the cold water supply mode. Further, the flow command unit 54 outputs a flow command such that the flow rate Q of the water flowing through the water treatment device 6 becomes the first flow rate Qmax (100% flow rate). The chilled water supply mode is a flow path mode in which the back pressure P of the water treatment device 6 can be minimized because the feedwater CW is bypassed for both the first heat exchanger 31 and the second heat exchanger 32. . Therefore, in a state where the flow rate Q is adjusted to the first flow rate Qmax (100% flow rate), the chilled water supply mode in which the excessive back pressure P is not applied to the water treatment apparatus 6 is selected, and the water treatment apparatus 6 is heated. The water supply CW in the empty state is supplied to the water supply tank 2.

  When the detected water level value of the water level sensor 4 exceeds the first middle water level threshold LM1, the mode determination unit 55 determines the flow path mode to be the second hot water supply mode (parallel water supply mode). The control command output unit 56 controls each of the valves 41 to 44 so as to shift the flow path mode from the cold water supply mode to the second hot water supply mode. In addition, the flow command unit 54 outputs a flow command such that the flow rate Q of the water in the water treatment device 6 becomes the second flow rate Qmid (60% flow rate). In the second hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than that in the cold water supply mode because the feedwater CW flows through both the first heat exchanger 31 and the second heat exchanger 32 in parallel. Is a flow channel mode that can be suppressed lower than the first hot water supply mode. Therefore, in the state where the flow rate Q is adjusted to the second flow rate Qmid (60% flow rate), the second hot water supply mode can heat the feedwater CW without applying an excessive back pressure P to the water treatment device 6. Is supplied, and the feedwater CW individually heated in the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feedwater tank 2.

  When the detected water level value of the water level sensor 4 exceeds the second middle water level threshold LM2, the mode determination unit 55 determines the flow path mode to be the first hot water supply mode (series water supply mode). The control command output unit 56 controls the valves 41 to 44 so as to shift the flow path mode from the second hot water supply mode to the first hot water supply mode. Further, the flow rate command unit 54 outputs a flow rate command such that the flow rate Q of the water flowing through the water treatment device 6 is maintained at the second flow rate Qmid (60% flow rate). In the first hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than in the second hot water supply mode because the feedwater CW flows in series to the first heat exchanger 31 and the second heat exchanger 32. Is a flow channel mode in which higher temperature feedwater CW can be generated. Therefore, in a state where the usage amount of the water supply CW is reduced and the water level of the water supply tank 2 is rising from the second middle water level threshold LM2 toward the high water level threshold LH, the back pressure P is excessively applied to the water treatment device 6. The first hot water supply mode in which the feed water CW can be heated to a higher temperature without any heat is selected, and the feed water CW heated in two stages by the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feed water tank 2. I do.

  When the detected water level value of the water level sensor 4 exceeds the high water level threshold LH, the flow rate command unit 54 outputs a flow rate command such that the flow rate Q of the water in the water treatment device 6 becomes the third flow rate Qmin (0% flow rate). I do. As a result, the supply of the feedwater CW to the feedwater tank 2 is stopped, and the feedwater heating system 1 waits in the first hotwater supply mode until the flow of water is restarted.

<Third embodiment>
Next, a third mode of the mode switching method will be described. In the third embodiment, the control device 50 switches the flow path of the feedwater CW to the feedwater tank 2 to a predetermined mode in accordance with the flow rate Q of the water treatment device 6 adjusted by the flow rate adjusting device 8. Each of the valves 41 to 44 is controlled.

  In the third embodiment, the mode determination unit 55 determines the mode based on the flow command output from the flow command unit 54 to control the flow control device 8. Note that the second mode is a switching method in which the mode determination with reference to the water level and the flow rate command output are independent, whereas the third mode is a switching method in which the mode determination is dependent on the flow rate command output, Both provide the same control result in appearance.

  When the detected water level value of the water level sensor 4 falls below the low water level threshold value LL, the flow rate command unit 54 outputs a flow rate command such that the flow rate Q of the water in the water treatment device 6 becomes the first flow rate Qmax (100% flow rate). I do. When the flow command of the 100% flow rate is output, the mode determining unit 55 determines the flow path mode to be the cold water supply mode. The control command output unit 56 controls the valves 41 to 44 so as to shift the flow path mode from the first hot water supply mode (series water supply mode) to the cold water supply mode. The chilled water supply mode is a flow path mode in which the back pressure P of the water treatment device 6 can be minimized because the feedwater CW is bypassed for both the first heat exchanger 31 and the second heat exchanger 32. . Therefore, in a state where the flow rate Q is adjusted to the first flow rate Qmax (100% flow rate), the chilled water supply mode in which the excessive back pressure P is not applied to the water treatment apparatus 6 is selected, and the water treatment apparatus 6 is heated. The water supply CW in the empty state is supplied to the water supply tank 2.

  When the detected water level value of the water level sensor 4 exceeds the first middle water level threshold LM1, the flow rate command unit 54 sets the flow rate command so that the flow rate Q of the water in the water treatment device 6 becomes the second flow rate Qmid (60% flow rate). Is output. When the flow command of the 60% flow rate is output, the mode determining unit 55 determines the flow path mode to be the second hot water supply mode (parallel water supply mode). The control command output unit 56 controls each of the valves 41 to 44 so as to shift the flow path mode from the cold water supply mode to the second hot water supply mode. In the second hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than that in the cold water supply mode because the feedwater CW flows through both the first heat exchanger 31 and the second heat exchanger 32 in parallel. Is a flow channel mode that can be suppressed lower than the first hot water supply mode. Therefore, in the state where the flow rate Q is adjusted to the second flow rate Qmid (60% flow rate), the second hot water supply mode can heat the feedwater CW without applying an excessive back pressure P to the water treatment device 6. Is supplied, and the feedwater CW individually heated in the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feedwater tank 2.

  When a flow rate command of a 60% flow rate is output and the output state continues for a predetermined time t (for example, 5 minutes), the mode determination unit 55 determines the flow path mode to be the first hot water supply mode (series water supply mode). The control command output unit 56 controls the valves 41 to 44 so as to shift the flow path mode from the second hot water supply mode to the first hot water supply mode. In the first hot water supply mode, the back pressure P of the water treatment device 6 becomes higher than in the second hot water supply mode because the feedwater CW flows in series to the first heat exchanger 31 and the second heat exchanger 32. Is a flow channel mode in which higher temperature feedwater CW can be generated. Therefore, in a state where the usage amount of the feedwater CW is small and the flow command of the flow command unit 54 is not switched to the 100% flow rate, the feedwater CW is heated to a higher temperature without excessively applying the back pressure P to the water treatment device 6. The first hot water supply mode capable of heating is selected, and the feedwater CW heated in two stages by the first heat exchanger 31 and the second heat exchanger 32 is supplied to the feedwater tank 2.

  When the detected water level value of the water level sensor 4 exceeds the high water level threshold LH, the flow rate command unit 54 outputs a flow rate command such that the flow rate Q of the water in the water treatment device 6 becomes the third flow rate Qmin (0% flow rate). I do. As a result, the supply of the feedwater CW to the feedwater tank 2 is stopped, and the feedwater heating system 1 waits in the first hotwater supply mode until the flow of water is restarted.

<Fourth embodiment>
Next, a fourth mode of the mode switching method will be described. The fourth mode is a switching method added to the above-described first to third modes. In the fourth embodiment, the control device 50 controls each of the valves 41 to 44 so that the flow path of the feedwater CW to the feedwater tank 2 is switched to a predetermined mode according to the detected temperature value of the temperature sensor 5.

  In the switching method according to the first to third embodiments, if the temperature detected by the temperature sensor 5 exceeds the temperature threshold TL while the feed water heating system 1 is operating in the first hot water supply mode, the mode is determined. The unit 55 switches the flow path mode from the first hot water supply mode to the third hot water supply mode or the fourth hot water supply mode. Thereby, the two-stage heating in the first heat exchanger 31 and the second heat exchanger 32 is switched to the one-stage heating in the first heat exchanger 31 or the second heat exchanger 32. As a result, the temperature can be lowered without changing the flow rate of the feedwater CW supplied to the feedwater tank 2.

  Further, in the switching method of the above-described first to third embodiments, if the detected temperature value of the temperature sensor 5 exceeds the temperature threshold TL while the feed water heating system 1 is operating in the second hot water supply mode, The mode determining unit 55 switches the flow path mode from the second hot water supply mode to the third hot water supply mode or the fourth hot water supply mode. Thereby, the two-row heating in the first heat exchanger 31 and the second heat exchanger 32 is switched to the one-row heating in the first heat exchanger 31 or the second heat exchanger 32, and the feed water is heated. The flow rate of the heat exchanger used is doubled. As a result, the temperature can be lowered without changing the flow rate of the feedwater CW supplied to the feedwater tank 2.

  In the first embodiment, if the detected temperature value of the temperature sensor 5 falls below the temperature threshold TL after switching to the third hot water supply mode or the fourth hot water supply mode, the flow mode is returned to the flow channel mode before the switching. In the second embodiment, when the detected temperature value of the temperature sensor 5 falls below the temperature threshold value TL after the mode is switched to the third hot water supply mode or the fourth hot water supply mode, the shift destination is referred to by referring to the detected water level value at that time. Is determined. In the third mode, when the detected temperature value of the temperature sensor 5 falls below the temperature threshold TL after switching to the third hot water supply mode or the fourth hot water supply mode, the flow destination command is output with reference to the flow rate command output at that time. Is determined.

  In the third hot water supply mode and the fourth hot water supply mode, the feedwater CW and the heat source water SW are not supplied to one of the heat exchangers that is not used for heating the feedwater. Therefore, maintenance of the heat exchanger that is not used can be performed. In order to prevent the maintenance of one of the heat exchangers from becoming infeasible, it is desirable to periodically replace the heat exchanger used for heating the feed water.

[Computer system]
FIG. 8 is a block diagram illustrating an example of the computer system 1000. The control device 50 includes a computer system 1000. The computer system 1000 includes: a processor 1001 such as a CPU (Central Processing Unit); a main memory 1002 including a nonvolatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory); It has a storage 1003 and an interface 1004 including an input / output circuit. The functions of the control device 50 described above are stored in the storage 1003 as a program. The processor 1001 reads the program from the storage 1003, expands the program in the main memory 1002, and executes the above-described processing according to the program. Note that the program may be distributed to the computer system 1000 via a network.

[effect]
As described above, according to the present embodiment, the water supply warming system 1 includes the first water supply line 11, the second water supply line 12, the third water supply line 13, the fourth water supply line 14, and the first water supply line 13. A first heat exchanger 31 for heating the feedwater CW flowing through the water supply line 11 and a second heat exchanger 32 for heating the feedwater CW flowing through the second water supply line 12 are provided. By switching the flow path of the feedwater CW to the feedwater tank 2 to a predetermined mode according to the situation of the feedwater tank 2 or the situation of the water treatment device 6, the feedwater heating system 1 efficiently recovers heat from the heat source water SW. can do.

  In the present embodiment, the control device 50 performs the first hot water supply mode in which high-temperature water heated at a required flow rate by a two-stage heat exchanger is supplied to the water supply tank 2; Switches to at least one of the second hot water supply modes in which the medium-temperature water heated by the two-row one-stage heat exchanger is supplied to the water supply tank 2. Therefore, by selecting one of the flow path modes in accordance with the back pressure P of the water treatment device 6, heat recovery can be performed while preventing the water treatment device 6 from being abnormal or malfunctioning. In addition, by selecting one of the flow path modes according to the water level of the water supply tank 2 and the flow rate of the water supply from the water treatment device 6, the lower the amount of the water supply CW used, the higher the temperature of the water supply CW. it can.

  In the present embodiment, the control device 50 switches to the cold water supply mode in which the supply water CW of a required flow rate is supplied to the water supply tank 2 while bypassing the heat exchanger. Therefore, when the back pressure P of the water treatment device 6 is too high, by selecting the chilled water supply mode, it is possible to reliably prevent the water treatment device 6 from abnormalities and failures while giving up heat recovery. . When the amount of water CW used is large and the water level L of the water supply tank 2 is low or the flow rate Q of water through the water treatment device 6 is maximum, the water supply tank is selected by selecting the cold water supply mode. 2, the water level L can be raised in a short time.

  In the present embodiment, the control device 50 switches to the third hot water supply mode or the fourth hot water supply mode in which the water CW of a required flow rate is supplied to one of the heat exchangers and supplied to the water supply tank 2. . Therefore, when the temperature of the feedwater CW stored in the feedwater tank 2 is too high, the heat recovery by the single-row two-stage heat exchanger or the double-row one-stage heat exchanger is switched to the heat recovery by the single-row one-stage heat exchanger. Thereby, the feedwater CW sent to the feedwater tank 2 can be adjusted to an appropriate temperature. In addition, maintenance of the other heat exchanger can be performed while heating the feedwater CW in one heat exchanger.

[Other embodiments]
In the above-described embodiment, the first valve 41 and the fourth valve 44 of the flow path switching means are three-way valves. The function of the first valve 41 may be exhibited by a valve unit including a plurality of two-way valves. Similarly, the function of the fourth valve 44 may be exhibited by a valve unit including a plurality of two-way valves.

  DESCRIPTION OF SYMBOLS 1 ... Feed water heating system, 2 ... Water supply tank, 3 ... Heat source water tank, 4 ... Water level sensor, 5 ... Temperature sensor, 6 ... Water treatment device, 7 ... Pressure sensor, 8 ... Flow control device, 9 ... Supply line, Reference Signs List 10 overflow path, 11 first water supply line, 11A upstream end, 11B downstream end, 11C middle part, 11D middle part, 11E outflow end, 11F inflow end, 12 second water supply line, 12A ... upstream end, 12B ... downstream end, 13 ... third water supply line, 13A ... upstream end, 13B ... downstream end, 14 ... fourth water supply line, 14A ... upstream end, 14B ... downstream end, 15 ... raw water line, 15B ... Downstream end, 16: hot water line, 16A: upstream end, 21: first heat source water line, 21A: upstream end, 21C: middle part, 21D: middle part, 22: second heat source water line, 22A: upstream end, 22B ... downstream end, 31 ... first heat Heat exchanger, 32 second heat exchanger, 41 first valve, 42 second valve, 43 third valve, 44 fourth valve, 50 control device, 51 detected water level acquisition unit, 52 Detected temperature value acquisition unit, 53: detected pressure value acquisition unit, 54: flow rate command unit, 55: mode determination unit, 56: control command output unit, 80: boiler, 81: hot water line, 82: hot water pump.

Claims (7)

A water tank for storing water,
A heat source water tank for storing heat source water,
A first water supply line for supplying water to the water tank;
A second water supply line for supplying water to the water tank;
A third water supply line for supplying water to the water supply tank;
A first heat source water line for sending heat source water from the heat source water tank;
A second heat source water line for sending heat source water from the heat source water tank;
A first heat exchanger that heats feedwater flowing through the first water supply line by heat exchange with heat source water flowing through the first heat source water line;
A second heat exchanger that heats feedwater flowing through the second water supply line by heat exchange with heat source water flowing through the second heat source water line;
A fourth water supply line connecting the first water supply line downstream of the first heat exchanger and the second water supply line upstream of the second heat exchanger,
Flow path switching means for switching a flow path of water supply to the water supply tank to a predetermined mode,
Control means for controlling the flow path switching means,
Water heating system equipped with. The flow path switching means,
A first hot water supply mode in which the supply of water in the third water supply line is interrupted, and the supply of water is circulated in the order of the first water supply line, the fourth water supply line, and the second water supply line;
A second hot water supply mode for interrupting the supply of water in the third water supply line and the fourth water supply line, and supplying water in parallel with the first water supply line and the second water supply line;
Is configured to be switchable to
The feedwater heating system according to claim 1. The flow path switching means,
The first hot water supply mode;
The second hot water supply mode;
A chilled water supply mode in which the first water supply line, the second water supply line, and the fourth water supply line are cut off to supply water, and only the third water supply line is supplied with water;
Is configured to be switchable to
The feedwater heating system according to claim 2. The flow path switching means,
The first hot water supply mode;
The second hot water supply mode;
The cold water supply mode,
A third hot water supply mode in which the second water supply line, the third water supply line, and the fourth water supply line are cut off to supply water and only the first water supply line is supplied with water;
A fourth hot water supply mode in which the first water supply line, the third water supply line, and the fourth water supply line are blocked from flowing water and the second water supply line is supplied with water only;
Is configured to be switchable to
The feedwater heating system according to claim 3. A raw water line for supplying water to the first water supply line, the second water supply line, and the third water supply line;
A water treatment device connected to the raw water line,
Pressure detection means for detecting the back pressure of the water treatment device,
The control means controls the flow path switching means such that a flow path of the water supply to the water supply tank is switched to a predetermined mode in accordance with a detected pressure value of the pressure detection means,
The feedwater heating system according to any one of claims 1 to 4. A raw water line for supplying water to the first water supply line, the second water supply line, and the third water supply line;
A water treatment device connected to the raw water line,
Water level detection means for detecting the water level of the water supply tank,
The control means controls the flow path switching means such that a flow path of water supply to the water supply tank is switched to a predetermined mode according to a water level value detected by the water level detection means,
The feedwater heating system according to any one of claims 1 to 4. A raw water line for supplying water to the first water supply line, the second water supply line, and the third water supply line;
A water treatment device connected to the raw water line,
Flow rate adjusting means for adjusting the flow rate of water passing through the water treatment device,
The control means controls the flow path switching means such that a flow path of water supply to the water supply tank is switched to a predetermined mode in accordance with the flow rate of water adjusted by the flow rate adjustment means,
The feedwater heating system according to any one of claims 1 to 4.

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