Hot water supply device

Abstract

In a hot water supply device having a rapid hot water operation function, the start of hot water supply use during rapid hot water operation is accurately detected. If the temperature of the fluid decreases while the supply of hot water is stopped, a rapid hot water operation is executed in which the fluid in a rapid hot water circulation path formed by the operation of the circulation pump (80) is heated by the heat exchanger (40). During the rapid hot water operation, the controller (10) performs flow rate constant control for adjusting the rotational speed of the circulation pump (80) so as to maintain the total flow rate (Qt) of the hot water supply device (1A) constant on the basis of the flow rate detection value (Qf) of the flow rate detector (75). During the rapid hot water operation, the controller (10) detects the hot water supply use at the hot water supply destination on the basis of a decrease in the rotational speed of the circulation pump (80) under the flow rate constant control.

Description

Technical Field

[0001] The present invention relates to a hot water supply device, and more particularly to a hot water supply device with a rapid hot water operation function. Background Art

[0002] As a type of hot water supply device, it has a so-called rapid hot water operation function that outputs hot water of appropriate temperature immediately after the hot water supply is started, even if the hot water supply is stopped for a long time. In order to achieve rapid hot water operation, it is necessary to operate the circulation pump even when the hot water supply is stopped (standby) to form a circulation flow path through the heat source.

[0003] In a hot water supply device having a rapid hot water operation function, when hot water supply is started by opening a hot water supply plug during rapid hot water operation, it is required to stop the circulation pump and return to normal hot water supply operation. That is, how to detect the use of hot water supply in a state where a flow rate is generated in the hot water supply device due to the operation of the circulation pump becomes an issue.

[0004] Japanese Patent Gazette No. 3171979 (Patent Document 1) describes a technique in which, in a circulating heat-insulating hot water supply device having a rapid hot water operation function, the outflow of hot water from a hot water supply tap is determined based on a flow rate detected by a flow rate detector provided in a circulation loop other than a return line. In particular, it is described that the outflow of hot water during the rapid hot water operation is detected by setting a flow rate value (determination flow rate) determined to be used for hot water supply to different values ​​between the operating state and the stopped state of the circulation pump.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] Japanese Patent No. 3171979 Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] However, in the hot water supply device of Patent Document 1, only the control of operation and stop is described with respect to the operation of the circulation pump during the rapid hot water operation. Therefore, due to the influence of individual differences of the circulation pump, differences in the conditions of the construction site of the hot water supply device (pipe resistance, etc.), and changes in the piping state over the years, there is a concern that the flow rate may be too large or too small than the appropriate value. In this case, in the method of Patent Document 1 that directly compares the flow rate detection value with the judgment value, there is a concern that the detection accuracy of the hot water supply during the rapid hot water operation may be reduced.

[0010] The present invention is made to solve such a problem, and an object of the present invention is to accurately detect the start of hot water supply use in a rapid hot water operation in a hot water supply device having a rapid hot water operation function.

[0011] [Technical means to solve the problem]

[0012] In one aspect of the present invention, a hot water supply device for supplying hot water to a hot water supply destination is provided. The hot water supply device includes: a heating mechanism, a first path, a second path, a rapid hot water circulation path, a flow detector, and a controller. The heating mechanism heats a circulating fluid. The first path introduces the fluid to the heating mechanism according to the hot water supply use of the hot water supply destination. The second path guides the fluid heated in the heating mechanism to the hot water supply destination. The rapid hot water circulation path is formed according to the operation of a circulation pump during a rapid hot water operation performed to increase the temperature of the fluid when the hot water supply to the hot water supply destination is stopped. The rapid hot water circulation path includes: a third path connected to the first path at a first connection point and connected to the second path at a second connection point; and a path in the first path and the second path that reaches the second connection point from the first connection point via the heating mechanism. The flow detector is arranged at a portion of the first path that is closer to the heating mechanism than the first connection point, or at a portion of the second path that is closer to the heating mechanism than the second connection point. During the rapid hot water operation, the controller adjusts the rotation speed of the circulation pump based on the flow detection value of the flow detector to maintain the total flow of the hot water supply device at the flow command value. Constant flow control. Furthermore, if the rotation speed is lower than the determination value under the flow rate constant control, the controller detects that the hot water supply destination is in use for hot water supply.

[0013] [Effects of the Invention]

[0014] According to the present invention, during the rapid hot water operation, the total flow rate is controlled to be constant by adjusting the rotation speed of the circulation pump, so that the hot water supply use of the hot water supply destination can be detected based on the decrease in the rotation speed of the circulation pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a block diagram illustrating the configuration of the hot water supply device according to this embodiment.

[0016] Figure 2 It is a block diagram for explaining the structure of a hot water supply device of a comparative example.

[0017] Figure 3 Yes Description Figure 1 A block diagram of an example of the hardware configuration of the controller shown.

[0018] Figure 4This is a block diagram for explaining flow rate control by a circulation pump applied during rapid hot water operation of the hot water supply device according to the present embodiment.

[0019] Figure 5 This is a graph showing the relationship between the rotation speed and flow rate of the flow pump in the rapid hot water operation.

[0020] Figure 6 This is a flowchart for explaining the control process of the rapid hot water operation in the hot water supply device according to the present embodiment.

[0021] Figure 7 Yes Description Figure 6 Flowchart of a process for setting a determination value used in a hot water supply control process.

[0022] Figure 8 This is a waveform diagram for explaining an operation example of the rapid hot water operation in the hot water supply device according to the present embodiment.

[0023] Fig. 9 This is a block diagram for explaining a modified example of the configuration of the hot water supply device according to the present embodiment.

[0024] [Explanation of Symbols]

[0025] 1A, 1B, 1#: Hot water supply device

[0026] 10: Controller

[0027] 11: Water inlet

[0028] 12: Hot water outlet

[0029] 13: Loop port

[0030] 18: Electronic circuits

[0031] 20: Water entry path

[0032] 21: Check valve

[0033] 22: Bypass path

[0034] 23: Cycle Path

[0035] 25: Hot water outflow path

[0036] 26, 27, 125, 127: Connection points

[0037] 30: Combustion mechanism

[0038] 40: Heat exchanger

[0039] 50: Flow control unit

[0040] 55: Change rate learning department

[0041] 60: Pump speed control unit

[0042] 71, 72, 73: Temperature detector

[0043] 75, 76: Flow detector

[0044] 80: Circulation pump

[0045] 90: Flow control valve

[0046] 92: Remote Control

[0047] 100: Frame

[0048] 110: Water inlet piping

[0049] 120: Hot water outflow pipe

[0050] 200: Hot water supply tap

[0051] Kp: rate of change

[0052] Qcr: circulation flow

[0053] Qf: flow detection value

[0054] Qt*: flow command value

[0055] Tb: Tank temperature

[0056] Th: hot water outflow temperature

[0057] Tini: Set time

[0058] Tint: interval time

[0059] Tr: Hot water supply set temperature

[0060] Trst: judgment time

[0061] Tset: Constant time

[0062] Tw: water inlet temperature DETAILED DESCRIPTION

[0063] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated in principle.

[0064] Figure 1 This is a block diagram for explaining the configuration of the hot water supply device 1A according to the present embodiment.

[0065] Reference Figure 1The hot water supply device 1A has a water inlet 11 connected to a water inlet pipe 110, a hot water outlet 12 connected to a hot water outlet pipe 120, and a circulation port 13 connected to a circulation pipe 130. Furthermore, the hot water supply device 1A includes a controller 10, a water inlet path 20, a check valve 21, a bypass path 22, a circulation path 23, a hot water outlet path 25, a combustion mechanism 30, a heat exchanger 40, a circulation pump 80, and a flow rate regulating valve 90 stored in a frame 100.

[0066] The water inlet path 20 is formed between the water inlet 11 and the input side (upstream side) of the heat exchanger 40 via a check valve 21. The combustion mechanism 30 typically includes a burner that generates heat by burning gas, oil, or the like.

[0067] The heat exchanger 40 heats and raises the temperature of low-temperature water (fluid) flowing from the water inlet path 20 using the heat generated by the combustion mechanism 30. The combustion mechanism 30 and the heat exchanger 40 constitute an embodiment of a "heating mechanism".

[0068] The hot water outflow path 25 is formed between the output side (downstream side) of the heat exchanger 40 and the hot water outflow outlet 12. The bypass path 22 connects between the water inlet path 20 and the hot water outflow path 25 without passing through the heat exchanger 40. The bypass path 22 is arranged at a location on the upstream side (input side) of the heat exchanger 40 that is further downstream than the connection point 27 with the circulation path 23 (at Figure 1 The flow regulating valve 90 is connected to a portion (connection point 26) on the downstream side (output side) of the heat exchanger 40 that is upstream of the connection point 125. The ratio of the flow rate of the heat exchanger 40 to the flow rate of the bypass path 22 (bypass flow rate ratio) is adjusted by controlling the opening of the flow regulating valve 90 by the controller 10.

[0069] In this bypass structure, part of the low-temperature water bypasses the heat exchanger 40 and is mixed downstream of the heat exchanger 40 while being kept in a non-heated state, thereby supplying hot water of an appropriate temperature from the hot water outlet 12. As a result, the output temperature from the heat exchanger 40 (heating mechanism) can be increased, which is advantageous in suppressing the discharge generated by the exhaust gas of the combustion mechanism 30 being cooled on the surface of the heat exchanger 40. In addition, even by controlling the bypass flow rate ratio, the hot water outflow temperature can be controlled to the hot water supply set temperature, thereby improving the responsiveness of the temperature control.

[0070] The circulation path 23 is formed between the circulation port 13 and the water inlet path 20 (connection point 27). A circulation pump 80 is inserted and connected to the circulation path 23. Alternatively, the circulation pump 80 can also be inserted and connected to the circulation pipe 130 outside the frame 100. The operation and stop of the circulation pump 80 are controlled by the controller 10.

[0071] exist Figure 1 In the hot water supply device 1A, the water inlet pipe 110 and the water inlet path 20 form a "first path" for introducing the fluid into the heating mechanism (heat exchanger 40), and the connection point 27 with the circulation path 23 corresponds to the "first connection point". Similarly, the hot water outflow path 25 and the hot water outflow pipe 120 form a "second path" for leading the fluid heated in the heating mechanism (heat exchanger 40) to the hot water supply destination 200 or the like, and the connection point 125 with the circulation pipe 130 corresponds to the "second connection point". In addition, the circulation path 23 and the circulation pipe 130 form a "third path".

[0072] A temperature detector 71 is disposed in the water inlet path 20. The temperature detector 71 detects the water inlet temperature Tw before being heated by the heat exchanger 40. In contrast, a temperature detector 72 and a temperature detector 73 are disposed in the hot water outflow path 25. The temperature detector 72 is disposed in the hot water outflow path 25 at a location downstream of the connection point 26 with the bypass path 22, and detects the hot water outflow temperature Th. On the other hand, the temperature detector 73 is disposed at a location upstream of the connection point 26, and detects the tank temperature Tb corresponding to the output temperature from the heat exchanger 40. The temperatures of the fluids detected by the temperature detectors 71 to 73 are input to the controller 10.

[0073] The hot water supply device 1A is provided with a flow detector 75. For example, the flow detector 75 is arranged in the water inlet path 20 at a position downstream of the flow regulating valve 90 corresponding to the branch point with the bypass path 22, and is arranged to detect the flow rate (tank flow rate) of the heating object in the heat exchanger 40. The flow rate detection value Qf based on the flow detector 75 is input to the controller 10.

[0074] When the hot water supply tap 200 is opened and hot water is supplied to the hot water supply destination, the low-temperature water is introduced into the water inlet path 20 by the supply pressure of the low-temperature water. Accordingly, when the flow detector 75 detects a flow (i.e., tank flow) exceeding the minimum operating flow (minimum order quantity (MOQ)) during the conduction of the operation switch of the hot water supply device 1A, the controller 10 operates the combustion mechanism 30, thereby starting the hot water supply operation. In addition, the hot water supply tap 200 is shown as a representative example of the "hot water supply destination" of the hot water supply device 1A. The hot water supply destination may also include a solenoid valve that turns on / off the outflow of hot water to a bathtub, etc., and is not limited to an operator that directly opens and closes the hot water through user operation.

[0075] During the hot water supply operation, the high-temperature water heated by the combustion mechanism 30 and the heat exchanger 40 is mixed with the low-temperature water passing through the bypass path 22 and then output from the hot water outflow pipe 120 to the hot water supply tap 200 via the hot water outflow outlet 12. During the normal hot water supply operation, the controller 10 stops the circulation pump 80 and controls the fluid temperature (hot water outflow temperature Th) detected by the temperature detector 72 to be input to the remote controller 92 ( Figure 3 ) of the hot water supply set temperature Tr. Specifically, the hot water outflow temperature can be controlled by a combination of control of the heating amount (heat generation) based on the combustion mechanism 30 and control of the bypass flow rate ratio based on the flow rate regulating valve 90.

[0076] When the hot water supply is stopped by closing the hot water supply tap 200 or the like, i.e., when the hot water supply operation is stopped, the temperature of the fluid retained in the hot water outflow path 25 and the hot water outflow pipe 120 decreases, so that after the next hot water supply operation starts, it may take time to supply hot water of an appropriate temperature to the hot water supply tap 200. Therefore, the hot water supply device 1A is provided with a quick hot water operation function for quickly supplying hot water of an appropriate temperature after the hot water supply operation starts.

[0077] The rapid hot water operation is realized by forming a rapid hot water circulation path including the heat exchanger 40 (heating means) by operating the circulation pump 80 during the stop of hot water supply from the hot water supply tap 200 or the like. For example, the rapid hot water operation can be started when hot water is not supplied and the fluid temperature (for example, the tank temperature Tb and / or the hot water outflow temperature Th detected by the temperature detector 72 or the temperature detector 73) is lower than the rapid hot water start determination temperature (for example, set to a predetermined temperature lower than the hot water supply set temperature) during the period when the rapid hot water operation mode is turned on by a switch operation or a timer setting.

[0078] The rapid hot water circulation path is composed of a loop from the circulation port 13, through the circulation path 23, the water inlet path 20 (downstream of the connection point 27), the heat exchanger 40, the hot water outflow path 25, the hot water outflow port 12, the hot water outflow pipe 120 (upstream of the connection point 125), and the circulation pipe 130, and returns to the circulation port 13. In this way, the rapid hot water circulation path is formed to include the path from the connection point 27 to the connection point 125 through the heat exchanger 40 (heating means) among the "third path (circulation path 23 and circulation pipe 130)", and the "first path (water inlet pipe 110 and water inlet path 20)" and the "second path (hot water outflow path 25 and hot water outflow pipe 120)".

[0079] When the rapid hot water circulation path is formed by the operation of the circulation pump 80, the flow rate detection value Qf (i.e., the tank flow rate) of the flow rate detector 75 exceeds MOQ, and thus the combustion mechanism 30 is operated. As a result, the hot water in the rapid hot water circulation path is circulated and heated. The rapid hot water operation ends when the temperature of the fluid in the rapid hot water circulation path (e.g., the water inlet temperature Tw or the hot water outlet temperature Th detected by the temperature detector 71 or the temperature detector 72) reaches the rapid hot water end determination temperature (e.g., the hot water supply set temperature), the heating by the combustion mechanism 30 is stopped, and the circulation pump 80 is stopped.

[0080] In order to simplify the description, the flow regulating valve 90 is controlled to make the bypass flow ratio zero in the rapid hot water operation. In this case, it can be understood that the total flow Qt of the hot water supply device 1A in the rapid hot water operation, which is represented by the sum of the circulation flow Qcr of the circulation path 23 based on the operation of the circulation pump 80 and the flow Qin introduced into the water inlet path 20 according to the hot water supply use, passes through the flow detector 75 and the heat exchanger 40. Therefore, in the following, the flow detection value Qf in the rapid hot water operation directly represents the total flow Qt of the hot water supply device 1A.

[0081] In addition, even when the bypass flow ratio is controlled to something other than zero by the flow regulating valve 90, the total flow Qt of the hot water supply device 1A during rapid hot water operation can be calculated using the bypass flow ratio calculated based on the opening of the flow regulating valve 90 and the flow detection value Qf (flow detector 75).

[0082] If the hot water supply operation is continued while the circulation pump 80 is in operation, a portion of the hot water outflow from the hot water outlet 12 will not be supplied to the hot water supply destination. Therefore, it is preferable to quickly stop the circulation pump 80 and stop the rapid hot water operation when hot water supply is started by opening the hot water supply tap 200 during the rapid hot water operation. Therefore, it is necessary to detect and determine the start of hot water supply during the rapid hot water operation.

[0083] As an example, in the hot water supply device 1A, as described in Patent Document 1, the flow rate (circulation flow rate) of the rapid hot water circulation path under the driving condition is estimated based on the fixed driving condition of the circulation pump 80 during the rapid hot water operation, and a determination value for determining the hot water supply use under the circulation pump operation state is set corresponding to the estimated flow rate. However, as described above, there is a concern that the setting accuracy of the determination value may affect the determination accuracy of the hot water supply use.

[0084] In contrast, it is also possible Figure 2 As in the comparative example, a flow rate detector is added to detect the hot water supply during the rapid hot water operation.

[0085] Figure 2 This is a block diagram for explaining the structure of hot water supply device 1# according to the comparative example.

[0086] like Figure 2 As shown, Figure 1 Compared with the hot water supply device 1A of FIG. 1 , the hot water supply device 1# is different in that it further includes a flow rate detector 76 disposed in the circulation path 23 and detecting the circulation flow rate Qcr. The flow rate detection value (circulation flow rate Qcr) of the flow rate detector 76 is input to the controller 10 .

[0087] In the hot water supply device 1#, when no hot water supply is used during the rapid hot water operation (when the circulation pump 80 is in operation) (Qin=0), the flow rate detection value Qf (i.e., the total flow rate Qt) of the flow rate detector 75 is equal to the flow rate detection value Qcr of the flow rate detector 76. On the other hand, when hot water supply is used during the rapid hot water operation (when the circulation pump 80 is in operation) and the fluid is introduced from the water inlet 11 (Qin>0), the flow rate detection value Qf (total flow rate Qt) of the flow rate detector 75 is greater than the flow rate detection value Qcr of the flow rate detector 76.

[0088] Therefore, it can be understood that in the hot water supply device 1# of the comparative example, by comparing the difference (Qf-Qcr) between the flow rate detection value Qf and the flow rate detection value Qcr of the flow rate detector 75 and the flow rate detector 76 with a predetermined determination value, it is possible to determine whether hot water supply is used in the rapid hot water operation. On the other hand, in the hot water supply device 1#, there is a concern about the cost increase caused by the additional configuration of the flow rate detector 76.

[0089] In the hot water supply device 1A of this embodiment, in order to Figure 2 When the flow rate detector 76 is additionally arranged as in (hot water supply device 1#), the hot water supply use during the rapid hot water operation is accurately detected, and the control and determination described below are performed.

[0090] Figure 3 A block diagram illustrating a hardware configuration example of the controller 10 is shown.

[0091] Reference Figure 3, the controller 10 typically includes a microcomputer. The controller 10 includes a central processing unit (CPU) 15, a memory 16, an input / output (I / O) circuit 17, an electronic circuit 18, and a timer 19 for timing. The CPU 15, the memory 16, the I / O circuit 17, and the timer 19 can send and receive signals to each other via the bus 14. The electronic circuit 18 is configured to perform a predetermined operation process through dedicated hardware. The electronic circuit 18 can send and receive signals between the CPU 15 and the I / O circuit 17.

[0092] The CPU 15 receives output signals (detection values) from various sensors including the temperature detectors 71 to 73 and the flow rate detector 75 via the I / O circuit 17 .

[0093] The CPU 15 receives a signal indicating an operation instruction input to the remote controller 92 via the I / O circuit 17. The operation instruction includes, for example, an on / off operation of the operation switch of the hot water supply device 1A, a hot water supply setting temperature, and various time reservation settings (also referred to as "timer settings").

[0094] The CPU 15 generates an operation command for controlling each component including the combustion mechanism 30 and the circulation pump 80 so that the hot water supply device 1A operates according to the operation instruction. In this embodiment, the controller 10 inputs a detected value of the rotation speed Npm between it and the circulation pump 80, and outputs a control voltage Vpm for controlling the rotation speed.

[0095] The circulation pump 80 may include a direct current (DC) motor capable of controlling the rotation speed Npm according to a control voltage Vpm. As an example, a pulse voltage with a controlled pulse width is applied to the circulation pump 80 according to the control voltage Vpm, thereby increasing or decreasing the rotation speed Npm.

[0096] In the hot water supply device 1A, during the rapid hot water operation, the hot water supply use is detected based on the rotation speed behavior of the circulation pump 80 under the flow rate constant control of the circulation pump 80 described below.

[0097] Figure 4 This is a block diagram for explaining flow rate control by a circulation pump applied during rapid hot water operation of the hot water supply device 1A.

[0098] Reference Figure 4The flow control unit 50 includes a change rate learning unit 55 and a pump speed control unit 60. The functions of the change rate learning unit 55 and the pump speed control unit 60 can be realized by software processing of the controller 10 executing a predetermined program, but can also be partially or entirely realized by hardware processing based on electronic circuits or digital circuits.

[0099] The pump speed control unit 60 receives the flow rate deviation ΔQt (ΔQt=Qt*−Qt), which is the difference between the flow rate command value Qt* and the total flow rate Qt (Qt=Qf) during the rapid hot water operation, and the speed Npm of the circulation pump 80 .

[0100] The change rate learning unit 55 uses the actual values ​​of the rotation speed Npm of the circulation pump 80 and the total flow rate Qt to learn the change rate Kp defined by the ratio of the change (ΔNpm) in the rotation speed Npm of the circulation pump 80 to the change (ΔQt) in the total flow rate Qt (flow detection value Qf).

[0101] Figure 5 A graph showing the relationship between the rotation speed of the flow rate pump and the total flow rate during the rapid hot water operation is shown for explaining the change rate learned by the change rate learning unit 55 . Figure 5 The horizontal axis represents the rotation speed Npm of the circulation pump 80 , and the vertical axis represents the total flow rate Qt (Qt=Qf) based on the flow rate detection value Qf of the flow rate detector 75 .

[0102] exist Figure 5 In FIG. 1 , the relationship between the rotation speed Npm and the total flow rate Qt when no hot water supply is used (Qin=0) is plotted. The "square mark (white)", "circle mark (black)" and "square mark (black)" are plotted as the setting conditions for each of the three hot water supply devices 1A having different diameters of the circulation pipe 130.

[0103] according to Figure 5 It can be understood that in each hot water supply device 1A, the plot points of the rotation speed Npm and the total flow rate Qt are approximately located on the characteristic lines 101 to 103 represented by the linear function. That is, it can be understood that the ratio (change rate Kp) of the change amount (ΔNpm) of the rotation speed Npm of the circulation pump 80 to the change amount (ΔQt) of the total flow rate Qt, which is equivalent to the inverse of the slope of the linear function passing through the reference point (Npm0, Qt0), is determined for each hot water supply device 1A according to the installation conditions and the like.

[0104] For example, as part of the operation test during the construction when installing the hot water supply device 1A, the rate of change Kp and the actual measured value of the reference point (Npm0, Qt0) can be obtained based on the rotation speed Npm and the total flow rate Qt (flow detection value Qf) measured when the circulation pump 80 is operated and the constant flow control (total flow rate Qt) is performed. In addition, the reference point (Npm0, Qt0) is common between the characteristic lines 101 to 103, so as to be understood, it can also be handled as a parameter value unique to each model of the hot water supply device 1A.

[0105] Therefore, in the change rate learning unit 55, during the period when no hot water supply is used in the rapid hot water operation, each time the rotation speed Npm is detected, the flow rate detection value Qf (total flow rate detection value) at that time and Figure 5 The reference point (Npm0, Qt0) described above is used to calculate the actual measured value Kp0 of the rate of change Kp according to the following formula (1).

[0106] Kp0=(Npm-Npm0) / (Qt-Qt0)…(1)

[0107] Furthermore, when Kp0 is calculated by equation (1), the change rate learning unit 55 performs learning based on exponential smoothing calculation or the like shown in equation (2) to update the change rate Kp.

[0108] Kp=Kp1+α(Kp0-Kp1)…(2)

[0109] Kp1 in equation (2) represents the current value of the rate of change Kp, and Kp on the left represents the updated value after learning. The coefficient α (smoothing constant) is set within the range of 0<α<1.

[0110] Even if the rapid hot water operation is temporarily terminated, the learned value of the change rate Kp is not cleared. Therefore, when the rapid hot water operation is started, the value of the change rate Kp at the end of the previous rapid hot water operation is maintained and applied as the initial value.

[0111] Refer again Figure 4 The pump speed control unit 60 adjusts the control voltage Vpm of the circulation pump 80 and controls the total flow rate Qt (flow rate detection value Qf) to the flow rate instruction value Qt* so that the flow rate deviation ΔQt becomes zero.

[0112] At this time, the pump speed control unit 60 can calculate the speed change Npmc (Npmc=Kp·ΔQf) of the circulation pump 80 according to the product value of the change rate Kp and the flow rate deviation ΔQf from the change rate learning unit 55. Furthermore, the control voltage Vpm can be calculated according to the speed command value Npm* represented by the sum of the current speed Npm and the speed change Npmc.

[0113] The correspondence between the rotation speed command value Npm* and the control voltage Vpm can be predefined in a table or a calculation formula in the pump rotation speed control unit 60. For the table or the calculation formula, an offset can be learned using an error between the rotation speed command value Npm* and the actually detected rotation speed Npm.

[0114] according to Figure 4 The control structure shown in the figure performs feedback control to maintain the total flow rate Qt (flow rate detection value Qf of the flow rate detector 75) at a constant flow rate (flow rate command value Qt*) by adjusting the rotation speed Npm of the circulation pump 80 during the rapid hot water operation. As a result, the total flow rate during the rapid hot water operation can be optimized without being affected by individual differences of the circulation pump 80, differences in conditions of the construction site of the hot water supply device (pipe resistance, etc.), changes in the state of the pipe over the years, etc. For example, if the total flow rate is too large, there is a concern that the pipe will be corroded, or even if the capacity of the heating mechanism is maximized, the temperature rise will be insufficient, etc., but such problems can be solved.

[0115] Figure 6 This is a flowchart for explaining the control process of the rapid hot water operation in the hot water supply device according to the present embodiment. Figure 6 The control process shown is repeatedly started by the controller 10 when the hot water supply operation is stopped.

[0116] Reference Figure 6 The controller 10 determines the start condition of the rapid hot water operation in step (hereinafter simply referred to as "S") 110. S110 includes S111 to S114.

[0117] In S111, it is determined whether the rapid hot water operation mode is on. The rapid hot water operation mode is turned on / off, for example, according to a switch operation by a user. Alternatively, the on period of the rapid hot water operation mode may be set by a timer setting by a user or by learning from past history. S111 determines YES when the rapid hot water operation mode is on, and NO when it is off.

[0118] In S112, by comparing the flow rate detection value Qf with MOQ, it is determined whether the hot water supply is stopped. If Qf<MOQ due to the closing of the hot water supply tap 200, S112 is determined to be yes, and it is determined that the hot water supply is not in use (stopped). On the contrary, when hot water or water is output from the hot water supply device 1A and the flow rate detection value Qf≧MOQ, S112 is determined to be no.

[0119] In S113, the detected value of the fluid temperature in the rapid hot water circulation path, for example, the temperature detected value based on the temperature detector 72, that is, the hot water outflow temperature Th, is compared with the rapid hot water start determination temperature T1. The rapid hot water start determination temperature T1 is set to be lower than the hot water supply setting temperature Tr by α [°C] (T1 = Tr-α). For example, it can be set to about α = 10 [°C]. If Th < T1, S113 determines yes, on the other hand, when Th ≧ T1, it determines no. Alternatively, the tank temperature Tb may be compared with another determination temperature.

[0120] In S114, the interval time Tint of the rapid hot water operation, that is, the time elapsed since the last rapid hot water operation ended (the change of the circulation pump 80 from operation to stop) is compared with the determination time Trst. Trst can be set to about 15 minutes, for example. If Tint>Trst, S114 determines yes, on the other hand, when Tint≦Trst, it determines no.

[0121] When all S111 to S114 are judged as yes, the controller 10 judges S110 as yes and starts the rapid hot water operation. On the other hand, if any one of S111 to S114 is judged as no, S110 is judged as no and the rapid hot water operation is not started. Since the judgment of S112 is performed, it can be understood that the hot water supply is in the "not in progress" state when the rapid hot water operation starts.

[0122] When the rapid hot water operation is started, the controller 10 starts the circulation pump 80 through S120. When the rapid hot water circulation path is formed by the operation of the circulation pump 80, the controller 10 operates the combustion mechanism 30 according to the flow detection value Qf (tank flow rate) exceeding MOQ. As a result, for example, the combustion of the burner is turned on, and the fluid in the rapid hot water circulation path is heated.

[0123] Furthermore, the controller 10 executes S130 during the operation of the circulation pump 80. Figure 4 The flow rate constant control (Qf(Qt)=Qt*) based on the adjustment of the rotation speed Npm described in S130 is executed in parallel with the flow rate constant control based on the change rate learning unit 55 ( Figure 4 )’s rate of change Kp learning (updating).

[0124] In S140 , the controller 10 monitors the rotation speed Npm of the circulation pump 80 in order to detect the hot water supply use in the rapid hot water operation, and in S150 , performs the hot water supply use determination using the monitored rotation speed Npm.

[0125] exist Figure 1In the structure of , when the flow rate constant control (S130) is executed during the rapid hot water operation, if the hot water supply is started, the rotation speed Npm of the circulation pump 80 is adjusted so that the sum of the flow rate Qin introduced from the water inlet 11 and the circulation flow rate Qcr passing through the circulation pump 80, that is, the total flow rate Qt, is maintained at the flow rate command value Qt*. The rotation speed Npm of the circulation pump 80 is controlled by the flow rate constant control so that the circulation flow rate Qcr is reduced compared with that before the hot water supply is started.

[0126] Therefore, in S150, when the flow rate constant control in the rapid hot water operation is applied, the start of hot water supply use can be detected based on whether the rotation speed of the circulation pump 80 is reduced due to the hot water supply use exceeding the specified amount Nth. For example, regarding the specified amount Nth, the flow rate Qth (for example, Qth> the specified flow rate of MOQ) as a threshold for hot water supply use detection and the change rate Kp can be used to set Nth=Kp·Qth.

[0127] For example, by Figure 7 The determination in S150 can be performed by comparing the determination value set by the control process shown in the figure with the rotation speed Npm monitored in S140.

[0128] Reference Figure 7 , the controller 10 sets the judgment value used in the previous rapid hot water operation as the judgment value in this rapid hot water operation through S200. In addition, the initial value of the judgment value can be set based on the rotational speed Npm and the change rate Kp of the circulation pump 80 measured in the working test during the construction. Specifically, the judgment value can be initially set by subtracting the prescribed amount Nth calculated using the change rate Kp measured during the working test from the actual value of the rotational speed Npm during the working test. Thus, the judgment value can be set to be reduced by an amount corresponding to the prescribed amount Nth compared to the rotational speed Npm when no hot water supply is used in the rapid hot water operation, and the prescribed amount Nth is equivalent to the rotational speed reduction corresponding to the hot water supply use of the flow rate Qth.

[0129] Then, the controller 10 waits through S210 until the time elapsed from the start of the rapid hot water operation (start of the circulation pump 80) reaches the prescribed time Tini. The prescribed time Tini is set in a manner corresponding to the time required for the rotation speed Npm to stabilize under the flow rate constant control after the start of the circulation pump 80 (for example, Tini = about 20 [seconds]). Alternatively, in the determination of S210, the time elapsed after the flow rate detection value Qf (the detection value of the total flow rate Qt) of the flow rate detector 75 reaches the flow rate command value Qt* may be used.

[0130] When the specified time Tini has passed (when S210 is determined to be yes), the controller 10 reads the rotation speed Npm of the circulation pump 80 within the constant time Tset through S220 and S230. In S240, it is determined whether the change of the read rotation speed Npm is constant or less. For example, when the difference between the maximum and minimum values ​​of the rotation speed Npm within the constant time Tset is less than a predetermined reference value, S240 determines to be yes.

[0131] When the change of the rotation speed Npm is small (when the judgment of S240 is yes), the controller 10 calculates the average value of the rotation speed Npm (constant time Tset) read in S220 through S250. The calculated average value is used to update the determination value used in the determination of S150 through S260. In contrast, when the change of the rotation speed Npm is large (when the judgment of S240 is no), through S270, the determination value is maintained as the current determination value, that is, the determination value (last value) used in the previous rapid hot water operation.

[0132] Thus, the judgment value for detecting the use of hot water supply can be updated according to the actual rotation speed Npm under stable behavior. Specifically, the updated judgment value can be set by subtracting the Nth=Kp·Qth from the rotation speed Npm calculated in S250. In this way, the judgment value can be updated by reflecting the change of the actual value of the rotation speed Npm when no hot water supply is used in the rapid hot water operation. In addition, by monitoring the change of the judgment value over time, or the change of the change rate Kp (learning value) over time, it is also possible to detect the occurrence of blockage in the rapid hot water circulation path.

[0133] Refer again Figure 6 If the speed Npm monitored in S140 is greater than Figure 7 If the judgment value set in is low, the controller 10 judges that hot water is supplied and used, and judges S160 as yes. Thus, through S190, the circulation pump 80 is stopped, thereby ending the rapid hot water operation according to the start of hot water supply and use.

[0134] When the controller 10 determines that there is no hot water supply (no determination in S160), it further performs a temperature rise determination in S170. For example, in S170, it is determined whether the temperature detection value (water inlet temperature) Tw based on the temperature detector 71 reaches the hot water supply set temperature Tr* (Tw≧Tr).

[0135] When the temperature detection value (water inlet temperature) Tw reaches the hot water supply set temperature Tr* (YES in S170 ), the rapid hot water operation is terminated through S190 , similar to the YES determination in S160 .

[0136] On the other hand, when the temperature detection value (water inlet temperature) Tw is lower than the hot water supply setting temperature Tr* (when S170 is determined as "no"), the rapid hot water operation is continued through S180, and the process returns to S130. Thus, after the rapid hot water operation is started, the processes of S130 to S180 are repeatedly executed until the hot water supply is detected (when S160 is determined as "yes"), or until the fluid temperature of the rapid hot water circulation path reaches the hot water supply setting temperature Tr* (when S170 is determined as "yes").

[0137] Figure 8 2 is a waveform diagram for explaining an operation example of the rapid hot water operation in the hot water supply device according to the present embodiment. Figure 8 The horizontal axis is a time axis, and shows an operation example in which the rapid hot water operation is started at time t0 and the hot water supply is started at time tx.

[0138] exist Figure 8 , the rotation speed Npm of the circulation pump 80 (symbol 111: dotted line), the flow rate detection value Qf (symbol 112: solid line), the control voltage Vpm of the circulation pump 80 (symbol 113), and the flow rate Qcr (symbol 114) of the circulation path 23 are shown relative to the passage of time. In addition, the flow rate Qcr is obtained by configuring the comparative example ( Figure 2 ) The flow rate is experimentally determined by using the same flow rate detector 76. In addition, as described above, the flow rate detection value Qf is equivalent to the total flow rate Qt.

[0139] like Figure 8 As shown, before time tx, the flow rate detection value Qf (symbol 112) is equal to the circulation flow rate Qcr (symbol 114). In this case, the rotation speed Npm (symbol 111) is controlled so that Qf=Qt*.

[0140] When hot water supply is started at time tx by opening the hot water supply tap 200 or the like, the flow rate detection value Qf rises instantaneously by introducing low-temperature water from the water inlet 11. After time tx, the Qf constant control (S130) is continued to be executed, thereby reducing the control voltage Vpm (symbol 113) in order to reduce the rotation speed Npm (symbol 111) of the circulation pump 80, so that the flow rate detection value Qf decreases toward the flow rate instruction value Qt* equal to the value before time tx.

[0141] Accordingly, the circulation flow rate Qcr (symbol 114) decreases according to the hot water supply usage after time tx. As a result, at time ty, the rotation speed Npm of the circulation pump 80 decreases by more than the specified amount Nth and becomes lower than the judgment value. Therefore, S160 ( Figure 6) is judged to be yes, thereby detecting the use of hot water supply. In addition, by not using the change rate Kp (formula (1)) obtained when judging at time ty in the learning based on formula (2), the learning error can be suppressed.

[0142] In addition, Figure 6 In the example of directly monitoring the rotation speed Npm of the circulation pump 80 to detect the use of hot water supply, it is described. On the other hand, it can be understood that when the flow rate through the circulation pump 80 decreases with the use of hot water supply, the change (ΔQt) of the total flow rate Qt relative to the change (ΔNpm) of the rotation speed Npm, that is, the change rate Kp, in equation (1) also becomes smaller.

[0143] Therefore, even if the calculated value of the change rate Kp at each timing by the change rate learning unit 55 is used instead of the rotation speed Npm, the same execution can be performed. Figure 6 and Figure 7 That is, in S140 ( Figure 6 ), the calculated value of the rate of change Kp at the timing is monitored, and when the rate of change Kp decreases by more than a specified amount Kth, the use of hot water supply can be detected.

[0144] In this case, the predetermined amount Kth can be calculated as Kth=Npm0 / Qth using the flow rate Qth as the threshold and the rotation speed Npm0 when the water supply is not used. Figure 7 In the process, the determination value can be updated using the calculated value of the rate of change Kp based on the rate of change learning unit 55. The determination value can be initially set using the rotation speed Npm0 of the circulation pump 80 during the operation test (not used for hot water supply) and the measured value of the rate of change Kp.

[0145] And, in S150( Figure 6 ), the rate of change Kp monitored in S140 may be Figure 7 That is, even if the change rate Kp is used, it can be indirectly determined whether the rotation speed of the circulation pump 80 decreases by more than the specified amount Nth, and similarly, the hot water supply use in the rapid hot water operation can be detected.

[0146] As described above, according to the hot water supply device of this embodiment, during the rapid hot water operation, the total flow rate Qt (in Figure 1In the constant flow control, the hot water supply use at the hot water supply destination can be accurately detected based on the decrease in the rotation speed Npm between before and after the hot water supply use at the hot water supply destination. In particular, there is no need to Figure 2 ) is added as a flow detector 76 dedicated to the rapid hot water circulation path, so that the hot water supply and use during the rapid hot water operation can be detected.

[0147] In addition, in the present embodiment, an example is described in which the flow rate regulating valve 90 is controlled so that the flow rate of the bypass path 22 is zero, that is, the bypass ratio is zero during the rapid hot water operation. However, as described above, the total flow rate Qt during the rapid hot water operation can be calculated using the bypass ratio obtained based on the opening of the flow rate regulating valve 90 and the flow rate detection value Qf of the flow detector 75. Therefore, even if the bypass flow rate ratio is not zero or the bypass flow rate ratio is not a constant value, the flow rate constant control of the total flow rate Qt can be performed in the same manner. Therefore, the same hot water supply use can be detected based on the rotation speed Npm (or change rate Kp) of the circulation pump 80 under the flow rate constant control without restricting the control of the flow rate regulating valve 90.

[0148] In addition, it can be understood that regarding the flow detector 75, by being arranged at any position between the connection point 27 (water inlet path 20) and the heat exchanger 40 (heating mechanism), or between the heat exchanger 40 and the connection point 125 (hot water outlet pipe 120), the total flow Qt reflecting the increase in flow (Qin>0) caused by the use of hot water supply during rapid hot water operation can be detected.

[0149] Next, a modified example of the structure of the hot water supply device of this embodiment will be further described.

[0150] exist Fig. 9 2 is a block diagram illustrating a configuration of a hot water supply device 1B according to a modification of the present embodiment.

[0151] Reference Fig. 9 In the hot water supply device 1B, Figure 1 The hot water supply device 1A is different in that the circulation port 13 is not provided, and only the water inlet 11 and the hot water outlet 12 are provided.

[0152] The water inlet pipe 110 for receiving low-temperature water is connected to the water inlet 11 of the hot water supply device 1B and is also connected to the circulation pipe 130. That is, the circulation pipe 130 is connected between the water inlet pipe 110 and the hot water outflow pipe 120 in the hot water supply device 1B.

[0153] The circulation pump 80 is, for example, inserted and connected to the circulation pipe 130. Fig. 9As illustrated, the circulation pump 80 may be disposed outside the housing 100 , or may be inserted inside the housing 100 and connected to the water inlet path 20 .

[0154] During the hot water supply operation, by stopping the circulation pump 80, a hot water supply device 1B can be provided with a Figure 1 Therefore, the hot water supply device 1B can also perform the hot water supply operation similar to that of the hot water supply device 1A.

[0155] On the other hand, by operating the circulation pump 80 , a rapid hot water circulation path including the heat exchanger 40 (heating means) can be formed in the hot water supply device 1B as well as in the hot water supply device 1A.

[0156] Specifically, a rapid hot water circulation path can be formed by returning from the water inlet 11 through the water inlet path 20, the heat exchanger 40, the hot water outflow path 25, the hot water outflow outlet 12, the hot water outflow pipe 120 (closer to the upstream side than the connection point 125), the circulation pipe 130, and the water inlet pipe 110 (closer to the downstream side than the connection point 127) to the water inlet 11.

[0157] exist Fig. 9 In the hot water supply device 1B, the water inlet pipe 110 and the water inlet path 20 form a "first path" for introducing the fluid into the heating mechanism (heat exchanger 40), and the connection point 127 corresponds to the "first connection point". Similarly, the hot water outflow path 25 and the hot water outflow pipe 120 form a "second path" for exporting the fluid heated in the heating mechanism (heat exchanger 40) to the hot water supply destination such as the hot water supply tap 200, and the connection point 125 corresponds to the "second connection point". In addition, in Fig. 9 In the embodiment, a “third path” is formed by the circulation pipe 130.

[0158] exist Fig. 9 It can also be understood that the rapid hot water circulation path is formed as a path including the "third path (circulation piping 130)", the "first path (water inlet piping 110 and water inlet path 20)" and the "second path (hot water outflow path 25 and hot water outflow piping 120)", which reaches the connection point 125 from the connection point 127 via the heat exchanger 40 (heating mechanism).

[0159] exist Fig. 9 In the embodiment, the bypass path 22 is also arranged at a position (input side) on the upstream side (input side) of the heat exchanger 40 and further downstream than the connection point 127 with the circulation pipe 130. Figure 1 It is connected between a portion of the heat exchanger 40 on the downstream side (output side) and the upstream side of the connection point 125 (where the flow regulating valve 90 is arranged).

[0160] In the hot water supply device 1B, since the flow detector 75 and the temperature detectors 71 to 73 are also arranged in the rapid hot water circulation path in the same way as the hot water supply device 1A, by performing constant flow control of the total flow Qt based on the flow detection value Qf of the flow detector 75, it is possible to detect the hot water supply use in the rapid hot water operation in the same way as the hot water supply device 1A.

[0161] In addition, if Figure 1 and Fig. 9 As in the structural example, by configuring a flow detector 75 in the path bypassed by the bypass path 22, that is, between the branch point between the water inlet path 20 and the bypass path 22 (the configuration location of the flow regulating valve 90) and the connection point 26 between the hot water outflow path 25 and the bypass path 22, the flow rate (tank flow rate) passing through the heat exchanger 40 required for MOQ determination can be directly detected. On the other hand, the total flow rate of the entire hot water supply device can be calculated using the bypass ratio calculated based on the opening degree of the flow regulating valve 90.

[0162] In contrast, when the flow detector 75 is disposed between the connection point 27 (127) and the branch point (the location where the flow control valve 90 is disposed), or between the connection point 26 and the connection point 125, the total flow of the entire hot water supply device is directly detected, and the tank flow rate can be calculated using the bypass ratio. In this way, by disposing the flow detector 75 between the connection point 27 (127) of the "first path (water inlet pipe 110 and water inlet path 20)" and the heat exchanger 40 (heating mechanism), or between the connection point 125 of the "second path (hot water outflow path 25 and hot water outflow pipe 120)" and the heat exchanger 40, the total flow rate Qt can be obtained based on the flow detection value Qf of the flow detector 75 during both the hot water supply operation and the rapid hot water operation.

[0163] In addition, in the present embodiment, the heat source in the heating mechanism is not limited to the combustion mechanism 30 that performs heating by burning fuel, and any heat source can be applied.

[0164] In addition, in the present embodiment and its modified example, the structure of the hot water supply device provided with the bypass path 22 is exemplified, but even in the structure without the bypass path 22 and the flow regulating valve 90, by configuring between the connection point 27 (first path) or the connection point 125 (second path) and the heat exchanger 40 ( Figure 1 ), or between the connection point 127 (first path) or the connection point 125 (second path) and the heat exchanger 40 ( Fig. 9 ) flow detector 75 detects the same total flow rate Qt, thereby also being able to perform the detection of water supply use in rapid hot water operation in the same manner.

[0165] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A hot water supply device for supplying hot water to a hot water supply destination, the hot water supply device comprising: A heating mechanism for heating the circulating fluid; a first path for introducing the fluid to the heating mechanism according to hot water supply use at the hot water supply destination; a second path for directing the fluid heated in the heating mechanism to the hot water supply destination; as well as The rapid hot water circulation path is formed by the operation of the circulation pump during the rapid hot water operation performed to increase the temperature of the fluid while the hot water supply to the hot water supply destination is stopped. The rapid hot water circulation path comprises: a third path connected to the first path at a first connection point and connected to the second path at a second connection point; and Of the first path and the second path, a path from the first connection point to the second connection point via the heating mechanism, The hot water supply device also includes: a flow rate detector disposed at a portion of the first path closer to the heating mechanism than the first connection point, or at a portion of the second path closer to the heating mechanism than the second connection point; and The controller performs flow constant control based on the flow detection value of the flow detector to adjust the rotation speed of the circulation pump to maintain the total flow of the hot water supply device at the flow command value during the rapid hot water operation, and if the rotation speed is lower than the judgment value under the flow constant control, the hot water supply use at the hot water supply destination is detected.

2. The hot water supply device according to claim 1, wherein: The controller comprises: a change rate learning unit that learns a change rate, which is a ratio of a change amount of the rotation speed of the circulation pump to a change amount of the total flow rate when the rotation speed of the circulation pump changes, during the constant flow rate control; and The circulation pump control unit adjusts the rotation speed based on the change rate obtained by the change rate learning unit and a deviation between the flow rate detection value and the flow rate command value during the flow rate stabilization control.

3. The hot water supply device according to claim 2, wherein: The controller is When the change rate obtained by the change rate learning unit is lower than a determination value under the flow rate constant control, it is determined that the rotation speed has decreased, and use of the hot water supply at the hot water supply destination is detected.

4. The hot water supply device according to any one of claims 1 to 3, wherein: The hot water supply device further includes: a bypass path formed inside the housing of the hot water supply device between a portion of the first path downstream of the first connection point and a portion of the second path upstream of the second connection point so as to bypass the heating mechanism; and an adjusting valve for controlling a ratio between a first flow rate introduced from the first path to the heating mechanism and a second flow rate introduced to the bypass path, The regulating valve is controlled during the rapid hot water operation so that the second flow rate becomes zero.

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