Hot water supply system

Abstract

Provided is a hot water supply system capable of correctly recognizing an abnormality in an instant hot water operation. The hot water supply system (SY) includes a control unit (6) capable of performing an abnormality determination process in which, after the start of the instant hot water operation, even if the cumulative flow rate of hot water detected using a flow rate sensor (Sb) reaches a prescribed value of the cumulative flow rate at which the detection temperature of a normal temperature sensor (Sa) is expected to rise to a prescribed level or more, in the case where the detection temperature of the temperature sensor (Sa) does not rise to the prescribed level or more, it is determined whether or not the hot water supply terminal (8) is in an open state, and in the case where the hot water supply terminal (8) is not in the open state, it is determined that there is an abnormality in the instant hot water operation.

Description

Technical Field

[0001] This invention relates to a hot water supply system capable of providing instant hot water.

[0002] Here, the term "instant hot water operation" in this specification refers to the action of circulating or retaining heated hot water at a specified temperature or above in the hot water flow channel connected to the hot water supply terminal so that hot water at a specified temperature or above can flow out immediately from the hot water supply terminal when the hot water supply terminal in the hot water supply system is set to the open state. Background Technology

[0003] As a hot water supply system, there are hot water supply systems capable of providing hot water instantly, as described in Patent Documents 1 to 3.

[0004] Specifically, this hot water supply system can supply hot water heated by a heat exchanger to the hot water tap via the hot water outlet path. On the other hand, the hot water outlet path is connected to a return flow path including a pump, forming a hot water circulation path that allows the hot water to circulate along a certain path.

[0005] In the hot water supply system with the structure described above, instant hot water operation is possible as follows: when the hot water tap is closed and the hot water supply stops, the hot water heated by the heat exchanger circulates or remains in the hot water circulation path. If the instant hot water operation described above is performed, and then the hot water tap is turned on, hot water at a specified temperature or higher in the hot water circulation path flows out immediately from the hot water tap, which is very convenient.

[0006] However, as stated below, there is room for improvement.

[0007] That is, like other general hot water supply systems, it is desirable to be able to properly detect any abnormalities in the operation of the hot water supply system. Furthermore, there are situations where it is unsuitable to continue operation when the hot water supply system malfunctions; therefore, there are also situations where the operation of the hot water supply system should be forcibly stopped when an abnormality occurs.

[0008] Here, if the malfunction in the hot water supply system is something like the hot water not being heated, the maintenance manager or user can relatively easily detect this malfunction. In contrast, when instant hot water is running, as long as the hot water tap is not turned on, the hot water heated by the heat exchanger continues to exist in the hot water circulation path and will not come into contact with the user's hands. Therefore, malfunctions in instant hot water operation are uniquely difficult for maintenance managers or users to detect.

[0009] [Existing Technical Documents]

[0010] [Patent Literature]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2020-34193

[0012] [Patent Document 2] Japanese Patent Application Publication No. 2011-247487

[0013] [Patent Document 3] Japanese Patent Application Publication No. 2003-336899 Summary of the Invention

[0014] [The problem the invention aims to solve]

[0015] The present invention was conceived based on the situation described above, and its objective is to provide a hot water supply system that can accurately detect any abnormalities in the instantaneous operation of hot water.

[0016] [Technical means to solve the problem]

[0017] To address the aforementioned issues, the following technical means are described in this invention.

[0018] The hot water supply system provided by the present invention includes: a heat exchanger for heating hot water; a hot water circulation path, including: a hot water outlet path connecting the hot water outlet of the heat exchanger to a hot water supply terminal; a return flow path connected at one end to the vicinity of the hot water supply terminal and capable of returning the hot water from the hot water outlet path to the inlet of the heat exchanger; and a pump for hot water circulation; a flow sensor for detecting hot water flow rate disposed in the hot water circulation path; a temperature sensor for detecting hot water temperature disposed in the return flow path; and a control unit capable of performing the following action control for real-time hot water operation: that is, circulating or retaining the hot water heated by the heat exchanger in the hot water circulation path; and the control unit is configured to perform the following abnormality judgment processing: after the real-time hot water operation starts, even if the cumulative flow rate of the hot water detected by the flow sensor reaches a predetermined value of the cumulative flow rate that the temperature detected by the temperature sensor can normally predict to rise to a predetermined level, but the temperature detected by the temperature sensor does not rise to a predetermined level, it is determined whether the hot water supply terminal is in an open state; if the hot water supply terminal is not in an open state, it is determined that the real-time hot water operation is abnormal.

[0019] Based on this structure, the following effects are achieved.

[0020] That is, when heated hot water obtained through the heat exchanger is sent to the hot water circulation circuit upon the start of instant hot water operation, if the cumulative flow rate of this heated hot water reaches a predetermined value, such as the capacity of the hot water circulation circuit, the hot water temperature detected by the temperature sensor should rise above a predetermined level (except in the case where the hot water supply terminal is turned on during instant hot water operation, and heated hot water flows out of the hot water supply terminal to the outside). According to the present invention, if the normal operation described above does not occur when instant hot water operation starts, the control unit correctly determines that there is an abnormality in instant hot water operation. As a result, corresponding measures can be taken, such as forcibly stopping instant hot water operation or allowing maintenance personnel or users to notice the key points of the abnormality in advance.

[0021] Preferably, in this invention, the determination of whether the hot water supply terminal is in the open state is made by determining whether there is flow detection using the flow sensor when the pump driven at the start of the instant hot water operation is stopped. If the flow detection is present, the hot water supply terminal is determined to be in the open state.

[0022] Based on this structure, it is possible to accurately determine whether the hot water supply terminal is in the open state through the control of the control unit during the instant hot water operation.

[0023] Preferably, in this invention, if an abnormal phenomenon occurs after the instant hot water operation has started, the instant hot water operation is restarted. If the number of repetitions of the abnormal phenomenon reaches a predetermined number, a final judgment is made that there is an abnormality in the instant hot water operation, and a reporting action for this abnormality is performed.

[0024] Based on this structure, careful final judgment of any abnormalities in the instantaneous hot water operation can appropriately prevent misjudgments.

[0025] Preferably, in this invention, the control unit is configured to perform a trial run of the instantaneous hot water operation, and during this trial run, to measure the cumulative flow rate of the hot water from the point when heated hot water is first sent from the heat exchanger to the hot water circulation path until the heated hot water reaches the position of the temperature sensor and the detected temperature rises as obtained by the temperature sensor, and to use this measured value as the predetermined value.

[0026] According to this structure, the capacity (flow channel volume) from the heat exchanger to the temperature sensor in the hot water circulation path can be used as the specified value, and this specified value can be set to be close to the overall capacity of the hot water circulation path. The length of the hot water circulation path varies depending on the setup conditions of the hot water supply system. In contrast, according to this structure, through trial operation of instant hot water operation, the control unit can learn an approximate value of the capacity of the hot water circulation path, which is very convenient.

[0027] Other features and advantages of the invention will become more apparent with reference to the accompanying drawings and the following description of embodiments of the invention. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating an example of the hot water supply system of the present invention.

[0029] Figure 2 (a) and Figure 2 (b) means Figure 1 The diagram shown is a schematic illustration of the operation of a hot water supply system. Figure 2 (a) represents an example of instant hot water operation. Figure 2 (b) represents an example of learning control of the capacity of the hot water circulation circuit.

[0030] Figure 3 It indicates that the process is being carried out. Figure 2 (b) Flowchart of the sequence of actions under the condition of learning control of the capacity of the hot water circulation circuit.

[0031] Figure 4 It indicates that the process is being carried out. Figure 2 A flowchart of the sequence of actions in the case of instantaneous hot water operation (a).

[0032] Figure 5 (a) and Figure 5 (b) is a schematic diagram illustrating another example of the hot water supply system of the present invention.

[0033] [Explanation of Symbols]

[0034] SY, SYa: Hot water supply system

[0035] A: Hot water supply device

[0036] C: Hot water circulation circuit

[0037] Sa: Temperature sensor

[0038] Sb, Sc: Flow sensors

[0039] Sd: Temperature sensor

[0040] P: Pump

[0041] Va: Check valve

[0042] V1: Three-way valve

[0043] V2: Flow regulating valve

[0044] 1: Water inlet

[0045] 1a: Internal water inlet channel

[0046] 1b: External water inlet

[0047] 16: External bypass channel

[0048] 17: Sub-department

[0049] 18: Bypass channel

[0050] 19: Water supply source

[0051] 2: Hot water supply line

[0052] 2a: Internal hot water supply circuit

[0053] 2b: External hot water outlet

[0054] 3: Return to flow channel

[0055] 3a: Internal return flow channel

[0056] 3b: External return flow channel

[0057] 4: Heat exchanger

[0058] 4a: Inlet

[0059] 4b: Hot water outlet

[0060] 5: Burner

[0061] 6: Control Department

[0062] 60: Remote Control

[0063] 60a: Operating switch

[0064] 60b: Display unit

[0065] 7: Packaging box

[0066] 8: Mixer faucet (hot water supply terminal)

[0067] S1~S7, S11~S18, S20~S29: Steps Detailed Implementation

[0068] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0069] Figure 1 The hot water supply system SY shown includes: a hot water supply device A, an inlet water line 1, a hot water outlet water line 2, and a return flow channel 3. The hot water supply device A is a structure that houses a heat exchanger 4, a burner 5, and a control unit 6 for hot water heating within a packaging box 7. The burner 5 is, for example, a gas burner or an oil burner. The heat exchanger 4 is constructed using finned tubes, for example, and can use the combustion gases generated by the burner 5 to heat the hot water fed into the heat exchanger 4.

[0070] Water inlet 1 is a piping channel that connects an external water supply source 19, such as a tap water pipe, to the water inlet 4a of the heat exchanger 4, allowing water to enter the heat exchanger 4. It is divided into an internal water inlet 1a located inside and outside the packaging box 7, and an external water inlet 1b. The external water inlet 1b is also connected to the water supply side of the mixing faucet 8 via a branch pipe section 17. The mixing faucet 8 is an example of a hot water supply terminal.

[0071] Hot water outlet circuit 2 connects the hot water outlet 4b of heat exchanger 4 to the hot water supply section of mixing faucet 8, supplying hot water to mixing faucet 8. It is divided into an internal hot water outlet circuit 2a and an external hot water outlet circuit 2b, located inside and outside the packaging box 7 respectively. The internal hot water outlet circuit 2a is connected to the internal water inlet circuit 1a via a three-way valve V1 that can adjust the flow rate and a bypass channel 18, allowing the hot water flowing in the internal hot water outlet circuit 2a to mix with unheated hot water. By controlling the mixing ratio, the hot water temperature is controlled to the desired target hot water supply temperature. A temperature sensor Sd for detecting the hot water temperature and a flow adjustment valve V2 are installed in the internal hot water outlet circuit 2a.

[0072] The return flow channel 3 is formed by connecting the part near the mixing faucet 8 of the hot water outlet 2 and the middle part of the internal water inlet channel 1a. It is divided into an internal return flow channel 3a and an external return flow channel 3b located inside and outside the packaging box 7, respectively. A hot water circulation pump P and a flow sensor Sb are installed in the internal return flow channel 3a.

[0073] If pump P is driven, then as follows Figure 2 As shown by the thick line in (a), hot water flowing from heat exchanger 4 to hot water outlet 2 can be returned to heat exchanger 4 via return channel 3. These heat exchangers 4, hot water outlet 2, and return channel 3 constitute the hot water circulation path C. In the instantaneous hot water operation of the hot water supply system SY, hot water is heated to... Figure 2 The path shown by the thick line in (a) is used for circulation.

[0074] The flow sensor Sb is used to detect the flow rate of hot water in the hot water circulation path C. Figure 2When the instant hot water is running as shown in (a), hot water flows out when the hot water supply section of the mixing faucet 8 is set to the open state, and the hot water flow rate is reduced by the flow sensor Sb.

[0075] also, Figure 2 (b) is described below.

[0076] Strictly speaking, the portion of the internal inlet water path 1a that is closer to the heat exchanger 4 than the connection point with the internal return flow path 3a is also equivalent to a part of the return flow path 3 (and the hot water circulation path C). A flow sensor Sc and a temperature sensor Sa are installed in this part. The flow sensor Sc is used to detect the inlet water flow rate into the heat exchanger 4, and the temperature sensor Sa is used to detect the inlet water temperature into the heat exchanger 4.

[0077] The control unit 6 is constructed using a microcomputer or the like, and performs operation control of each part of the hot water supply device A. However, as will be described later, it also performs control of real-time hot water operation, learning control for real-time hot water operation, and abnormal judgment and handling to detect abnormalities in real-time hot water operation.

[0078] The control unit 6 is connected to a remote control 60, for example, installed in a bathroom or kitchen. This remote control 60 includes multiple operation switches 60a, a display unit 60b for displaying data, and a speaker (not shown) capable of generating various sound information or warning sounds.

[0079] Secondly, refer to Figure 3 and Figure 4 The flowchart illustrates an example of the action control in the hot water supply system SY, as well as its function.

[0080] In the hot water supply system SY, real-time hot water operation, as described later, is possible, but this requires prior execution of the "control of the capacity of the hot water circulation path C," as described below. This control is performed during the trial operation of the hot water supply system SY.

[0081] Specifically, firstly, if the operation switch 60a of the remote control 60 is operated to select the instant hot water operation test run, then in order to perform this test run, the pump P is set to drive on by the control unit 6 (S1: YES, S2). As a result, the circulation of hot water in the hot water circulation path C begins, and the burner 5 starts to drive combustion, and heated hot water also begins to flow from the heat exchanger 4 to the hot water outlet path 2 (S3). In addition, the control unit 6 then starts to measure (count) the cumulative flow rate Q of the hot water in the hot water circulation path C using the flow sensor Sb (S4).

[0082] On the other hand, control unit 6 monitors the hot water temperature detected by temperature sensor Sa. If the hot water temperature rises above a specified temperature, the counting of the accumulated flow rate Q ends at this point in time, and this count value (e.g., Qa) is regarded as an approximate value (or approximate value) of the capacity of the hot water circulation path C and stored (S5: YES, S6). The situation where the hot water temperature detected by temperature sensor Sa rises above a specified temperature is as follows: Figure 2 As shown in (b), the heated hot water obtained by heat exchanger 4 reaches the location of temperature sensor Sa as indicated by the thick line in the figure. At this time, the volume of heated hot water is close to the capacity of hot water circulation path C, so it is not a problem to regard the count value Qa as an approximate value Qa of the capacity of hot water circulation path C. The approximate value Qa corresponds to an example of the so-called specified value in this invention (usually a specified value when the detected temperature of the temperature sensor can be expected to rise to a specified value or higher).

[0083] After the process is completed, both pump P and burner 5 are set to drive off (S7).

[0084] Secondly, the implementation of instant hot water operation will be explained.

[0085] First, if the remote control 60 is operated to select the key point for starting instant hot water operation, then, similar to the trial operation, the pump P and burner 5 are sequentially turned on by the control unit 6, and the heated hot water obtained by the heat exchanger 4 is sent to the hot water circulation path C (S11: YES, S12, S13). Furthermore, from this point onwards, the control unit 6 begins counting the cumulative flow Q of the hot water in the hot water circulation path C (S14). Then, in the control unit 6, the abnormality detection counter is set to n = 0 (S15).

[0086] Then, if the cumulative flow rate Q does not exceed the approximate capacity Qa of the hot water circulation path C, and the hot water temperature detected by the temperature sensor Sa rises to a predetermined temperature (e.g., the same as the target hot water supply temperature), the control unit 6 determines that "the instantaneous hot water operation is normal" (S16: YES, S17: YES, S18). If the heated hot water obtained by the heat exchanger 4 reaches the location of the temperature sensor Sa in the hot water circulation path C, the detected temperature obtained by the temperature sensor Sa rises. Therefore, if the phenomenon described above can be observed, it is considered that the instantaneous hot water operation is normal. If it is determined that there is no abnormality, it is considered that it is not necessary to report this point using the remote control 60, etc., but it is also possible to configure it to report this point.

[0087] If it is determined that there are no abnormalities in the instant hot water operation... Figure 4The subsequent operation sequence is omitted, but the instant hot water operation continues afterward, maintaining the circulation of hot water heated to the specified temperature in the hot water circulation circuit C. This instant hot water operation is terminated by setting the mixing faucet 8 to the open state, performing an operation to end the instant hot water operation, or after a preset time for ending the instant hot water operation.

[0088] However, as an instant hot water system, it can also differ from the above and be configured as an instant hot water system in the following form, namely, with... Figure 2 Similarly, in the trial operation shown in (b), when the heated hot water obtained by the heat exchanger 4 reaches the location of the temperature sensor Sa and the temperature rise is detected, the pump P or the burner 5 is stopped. Even in the instant hot water operation as described above, heated hot water can be retained in the hot water circulation path C, and hot water at the required temperature can flow out immediately when the mixing faucet 8 is set to the open state.

[0089] Unlike the previous case, when the hot water temperature detected by temperature sensor Sa does not rise, there is a situation where the cumulative flow rate Q exceeds the approximate capacity Qa of the hot water circulation path C (S17: No, S16: No). In this case, after setting pump P to drive off, control unit 6 determines whether there is flow detection using flow sensor Sb (S20, S21). In this case, even if pump P is stopped, flow detection still exists, meaning that the mixing faucet 8 is set to the open state and hot water is being dispensed. As described above, when flow detection exists, control unit 6 does not determine that there is an abnormality and ends the counting process of cumulative flow rate Q (S21: Yes, S22). In this situation, since the mixing faucet 8 is set to the open state and hot water is being dispensed during the instant hot water operation, the operation switches from instant hot water operation to normal hot water supply operation.

[0090] In step S21, when the mixing faucet 8 is not open and there is no flow detection, the burner 5 is set to drive off (S21: NO, S23). Under these circumstances, there is a high possibility of abnormal operation of the instant hot water system. By driving off the burner 5, the danger can be avoided. Then, if the value n of the abnormality detection counter is less than, for example, "3", the control unit 6 sets the value n of the abnormality detection counter to +1, resets the count of the cumulative flow Q, and sets the pump P and the burner 5 to drive on respectively, so as to substantially restart the instant hot water operation (S24: YES, S25-S27).

[0091] If, during the restarted instant hot water operation, the detected temperature obtained by the temperature sensor Sa rises to the specified temperature before the cumulative flow rate Q exceeds the approximate value Qa, it is determined that the instant hot water operation is normal (S16: Yes, S17: Yes, S18).

[0092] In contrast, if a highly probable abnormality repeatedly occurs due to the failure to achieve the results described above, and the value n of the abnormality detection counter reaches, for example, "3", then the control unit 6 makes a final judgment that there is an immediate abnormality in the hot water operation, and executes the reporting action of the aforementioned point (S24: NO, S28). In this embodiment, the final judgment is made based on the condition that a highly probable abnormality repeatedly occurs, thus ensuring high reliability of this judgment.

[0093] The reporting action may include, for example, an image display performed by the display unit 60b of the remote control 60, or an audio output from the speaker. In the control unit 6, when it is determined that there is an abnormality in the instant hot water operation, the counting of the cumulative flow Q also ends (S29), but in this stage, both the pump P and the burner 5 are set to drive off, and the instant hot water operation has stopped.

[0094] Figure 5 (a) and Figure 5 (b) indicates another embodiment of the hot water supply system of the present invention. In the figures, the same symbols are used to mark the same or similar components as those in the embodiments described, and repeated descriptions are omitted.

[0095] Figure 5 The hot water supply system SYa shown in (a) includes an external bypass channel 16 that connects an external hot water outlet 2b to an external water inlet 1b. A portion of this external bypass channel 16 corresponds to a branch pipe section 17 that can supply water to the water supply section of the mixing faucet 8, but a check valve Va is provided in the portion closer to the external hot water outlet 2b than this branch pipe section 17, which only allows hot water to flow from the external hot water outlet 2b side to the external bypass channel 16 side.

[0096] On the other hand, pump P is installed in the internal water inlet passage 1a.

[0097] Figure 5 The portion shown by the thick line in (b) corresponds to the hot water circulation path C. The return flow path 3 includes: an external bypass flow path 16, an external water inlet path 1b, and an internal water inlet path 1a.

[0098] In the hot water supply system SYa of this embodiment, the external return channel 3b and internal return channel 3a, which are components of the hot water circulation path C, are no longer required in the previous hot water supply system SY. Therefore, the structure can be simplified and the manufacturing cost can be reduced.

[0099] This invention is not limited to the embodiments described herein. The specific structure of each part of the hot water supply system of this invention can be freely modified within the scope desired by this invention.

[0100] In the described embodiment, the "prescribed value" (usually a prescribed value when the temperature detected by the temperature sensor can be expected to rise to a predetermined level) is set as an approximate value Qa of the capacity of the hot water circulation path C, but it can be set to a different value. Furthermore, this value is not limited to the value learned by the control unit 6 during trial operation; for example, it can also be a value input by the operator of the hot water supply system SY through operation of the remote control 60.

[0101] This invention can also be applied to hot water supply systems that include a hot water storage tank. In this case, a liquid-liquid heat exchanger, for example, can be used as a heat exchanger for heating hot water, allowing the high-temperature hot water flowing from the hot water storage tank to be used as the medium for heating the hot water.

Claims

1. A hot water supply system, characterized in that, include: Heat exchangers for heating hot water; The hot water circulation circuit includes: a hot water outlet circuit connecting the hot water outlet of the heat exchanger to a hot water supply terminal, a return flow channel connected at one end to the vicinity of the hot water supply terminal of the hot water outlet circuit and capable of returning the hot water from the hot water outlet circuit to the inlet of the heat exchanger, and a pump for hot water circulation. A flow sensor for detecting hot water flow is installed in the hot water circulation path; A temperature sensor for detecting hot water temperature is installed in the return flow channel; and The control unit is capable of performing real-time hot water operation control, namely, circulating or retaining the hot water heated by the heat exchanger in the hot water circulation path; and The control unit is configured to perform the following abnormality detection processing: after the instant hot water operation starts, even if the cumulative flow of hot water detected by the flow sensor reaches a predetermined value that the temperature detected by the temperature sensor can predict to rise above a predetermined value, but the temperature detected by the temperature sensor does not rise above the predetermined value, it determines whether the hot water supply terminal is in the open state. If the hot water supply terminal is not in the open state, it determines that there is an abnormality in the instant hot water operation. The determination of whether the hot water supply terminal is in the open state is made by checking whether the flow sensor detects flow when the pump, which is driven to stop at the start of the instant hot water operation, is detected. If the flow sensor detects flow, the hot water supply terminal is determined to be in the open state. The determination of whether the hot water supply terminal is in the on state is performed during the continuous combustion state. When the hot water supply terminal is in the open state, the hot water supply system switches to normal hot water supply operation.

2. The hot water supply system according to claim 1, characterized in that, If an abnormal phenomenon occurs after the instant hot water operation has started, the instant hot water operation will be restarted. If the abnormal phenomenon is repeated a specified number of times, a final judgment will be made that there is an abnormality in the instant hot water operation, and the reporting action of the abnormality will be executed.

3. The hot water supply system according to claim 1, characterized in that, The control unit is configured to perform a trial run of the instantaneous hot water operation, and during the trial run, to measure the cumulative flow rate of the hot water from the point when heated hot water is first sent from the heat exchanger to the hot water circulation path until the heated hot water reaches the position of the temperature sensor and the detected temperature rise is obtained by the temperature sensor, and to use the measured value as the predetermined value.

4. The hot water supply system according to claim 2, characterized in that, The control unit is configured to perform a trial run of the instantaneous hot water operation, and during the trial run, to measure the cumulative flow rate of the hot water from the point when heated hot water is first sent from the heat exchanger to the hot water circulation path until the heated hot water reaches the position of the temperature sensor and the detected temperature rise is obtained by the temperature sensor, and to use the measured value as the predetermined value.

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