Patent Publication Number: US-11391469-B2

Title: Hot-water supply device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority of Japan patent application serial no. 2018-201556, filed on Oct. 26, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to a hot-water supply device, more particularly, to a hot-water supply device which has an instant hot-water operation function of circulating and heating hot-water in a hot-water supply path. 
     Related Art 
     In Japanese Laid-Open No. 2007-17128 (patent literature 1), a hot-water supply device is disclosed which has an instant hot-water operation function for supplying, by circulating and heating hot-water in a hot-water supply path, the hot water at an appropriate temperature immediately after a tap is opened. 
     In patent literature 1, a hot-water supply control system is disclosed in which a sensor for detecting movement of a user at home is used to predict hot-water outlet from a water supply path and select execution/stop of heat insulation circulation operation, and thereby reducing energy consumption of the heat insulation circulation operation. In patent literature 1, for example, a case is disclosed in which when human movement in a space near the water supply path is detected, it is determined that the human has woken up and control of preparing hot water in advance is started. 
     However, in the above configuration, the sensor for detecting the movement of the user at home and a communication component for communicating detection values of the sensor to a controller of a hot-water dispenser are required to be installed. Furthermore, the movement detected by the sensor may also be executed even when the hot-water dispenser is not required to be used. For example, there are cases in which the user simply passes by the space near the water supply path for movement. In addition, there is a risk that when the user wants to use hot-water immediately after the movement is detected in the sensor, the instant hot-water operation is not yet sufficient, and low-temperature water is provided. 
     SUMMARY 
     A hot-water supply device according to an aspect of the disclosure includes a hot-water dispenser, a hot-water supply path, a circulation path, a control portion, a first clock, and a flow rate sensor. The hot-water dispenser is used for supplying hot-water. The hot-water supply path is used for supplying the hot-water from the hot-water dispenser to a hot-water supply tap. The circulation path is used for carrying out instant hot-water operation which circulates and heats the hot-water remaining in the hot-water supply path. The control portion controls hot-water supply operation and the instant hot-water operation of the hot-water dispenser. The first clock can repeatedly measure unit times which are times in which a pattern of hot-water usage of a user makes a round. The flow rate sensor detects the supply of the hot-water from the hot-water supply tap. The control portion is configured to detect, for each of the unit times and based on detection signals of the flow rate sensor, a time zone in which the hot-water supply operation is carried out. The control portion is further configured to reserve, based on a time zone which is detected in a first unit time and in which the hot-water supply operation is carried out, a time zone in a second unit time following the first unit time in which the instant hot-water operation is carried out, and carry out the instant hot-water operation based on the reservation in the second unit time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a schematic configuration of a hot-water supply device according to an embodiment of the disclosure. 
         FIG. 2  is a function block diagram for illustrating a control configuration of the hot-water supply device according to the embodiment. 
         FIG. 3  is a diagram for illustrating setting of instant hot-water reservation based on hot-water supply storage in unit times (days). 
         FIG. 4  is a diagram for illustrating cancellation of the instant hot-water reservation based on the hot-water supply storage in the unit times (days). 
         FIG. 5  is a flowchart for illustrating a setting method of a preheat time. 
         FIG. 6  is a flowchart for illustrating a storage method of a hot-water supply time. 
         FIG. 7  is a flowchart for illustrating a reservation method of instant hot-water operation. 
         FIG. 8  is a flowchart for illustrating an execution method of the instant hot-water operation. 
         FIG. 9  is a diagram for illustrating hot-water supply storage and instant hot-water reservation in unit times (weeks). 
         FIG. 10  is a sequence diagram for illustrating synchronization of a clock of a remote controller with a clock of a controller. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The disclosure provides a hot-water supply device which achieves both energy saving and user comfort. 
     According to the hot-water supply device, the control portion can automatically reserve the time zone of the instant hot-water operation based on the time zone in which the hot-water supply operation is carried out, and the control portion can carry out the instant hot-water operation in the reserved time zone. Therefore, the time zone of the instant hot-water operation can be automatically reserved without requiring setting of the instant hot-water operation using a remote controller or the like by the user. In addition, the time zone of the instant hot-water operation is reserved based on a time zone in which the user uses the hot-water actually, and thus the instant hot-water operation can be carried out at a timing in accordance with the movement of the user. 
     According to the disclosure, the hot-water supply device which achieves both energy saving and user comfort can be provided. 
     An embodiment of the disclosure is specifically described with reference to drawings. Furthermore, in the following, the same or corresponding parts in the drawings are denoted by the same symbols, and the description thereof will not be repeated in principle. 
     Embodiment 
       FIG. 1  is a configuration diagram of a hot-water supply device according to the embodiment. 
     With reference to  FIG. 1 , a hot-water supply device  100  includes a hot-water dispenser  70 , a flowing water system  20 , a fuel system  30 , a controller  50 , and a remote controller  8 . The hot-water supply device  100  has an instant hot-water function for supplying, by circulating and heating hot-water in the hot-water supply path, the hot water at an appropriate temperature immediately after a tap is opened. 
     The hot-water dispenser  70  combusts fuel gas and supplies hot-water (high temperature water). The hot-water dispenser  70  includes a combustion portion  3 , a heat exchange portion  11 , a blower  10 , and an exhaust portion  6 . The combustion portion  3  is connected with the fuel system  30  and combusts the fuel gas supplied from the fuel system  30 . The heat exchange portion  11  recovers thermal energy of the combustion gas generated by the combustion in the combustion portion  3  and heats the flowing hot-water. The blower  10  supplies air to the combustion portion  3 . The exhaust portion  6  exhausts the combustion gas passing through the heat exchange portion  11  to the outside. 
     The flowing water system  20  includes pipes through which the hot-water flows. The flowing water system  20  has an inflow side pipe  22 , an outflow side pipe  23 , a bypass pipe  25 , and a hot-water supply return pipe  26 . The inflow side pipe  22  is a pipe for introducing low-temperature water supplied from a water supply source not shown to the heat exchange portion  11 . When a hot-water supply tap  60  is opened, the low-temperature water is supplied to the inflow side pipe  22  by water pressure of the water supply source. 
     The outflow side pipe  23  is a pipe for supplying high temperature water heated by heat exchange with the combustion gas in the heat exchange portion  11  to the hot-water supply tap  60  or a bathtub not shown. The bypass pipe  25  is arranged between the inflow side pipe  22  and the outflow side pipe  23 . The bypass pipe  25  is arranged to bypass the heat exchange portion  11  and supply the hot-water of the inflow side pipe  22  to the outflow side pipe  23 . In the bypass pipe  25 , a water supply side flow rate sensor  43  for detecting a flow rate of the hot-water and a bypass flow rate regulating valve  44  are arranged. An opening degree of the bypass flow rate regulating valve  44  is controlled by the controller  50 . By the control of the opening degree of the bypass flow rate regulating valve  44 , a ratio of the flow rate of the bypass pipe  25  to a flow rate of the heat exchange portion  11  can be controlled. 
     In the inflow side pipe  22 , a water inlet temperature sensor  27 , a hot-water side flow rate sensor  28 , and a check valve  48  are arranged. The hot-water side flow rate sensor  28  detects a flow rate of warm water introduced into the heat exchange portion  11 . The water inlet temperature sensor  27  detects a temperature of the hot-water introduced into the heat exchange portion  11  (hereinafter, also called “water inlet temperature”). Furthermore, the hot-water side flow rate sensor  28  and the water inlet temperature sensor  27  are disposed closer to a downstream side in a flowing direction of the hot-water than a connection portion  29  of the bypass pipe  25  in the inflow side pipe  22 . Detection values obtained by the water inlet temperature sensor  27  and the hot-water side flow rate sensor  28  are input to the controller  50 . The check valve  48  is arranged for flowing the hot-water in only one direction. 
     In the outflow side pipe  23 , a flow rate regulating valve  41  is disposed closer to an upstream side in the flowing direction of the hot-water than a connection portion  24  of the bypass pipe  25 . Furthermore, a hot-water outlet temperature sensor  42  is disposed closer to the downstream side in the flowing direction of the hot-water than the connection portion  24 . The hot-water outlet temperature sensor  42  detects a temperature (hereinafter, also called hot-water temperature) Tw of the hot-water flowing through the outflow side pipe  23 . The hot-water temperature Tw is a temperature of hot-water coming out of the hot-water supply tap  60  during the hot-water supply operation and is a temperature of hot-water circulating a circulation path described later during the instant hot-water operation. The hot-water temperature Tw is input from the hot-water outlet temperature sensor  42  to the controller  50 . An opening degree of the flow rate regulating valve  41  is controlled by the controller  50 . 
     The controller  50  is typically configured by a microcomputer and controls actions of the hot-water supply device  100  including the hot-water supply operation and the instant hot-water operation which are described later. The controller  50  controls actions of each machine using inputs of various sensors so as to make the hot-water supply device  100  act according to operation instructions input to the remote controller  8 . The controller  50  corresponds to one example of a “control portion”. 
     The hot-water supply device  100  further includes, as configurations for the instant hot-water operation, a circulation pump  45 , a circulation flow rate sensor  47  and a check valve  46  together with the hot-water supply return pipe  26 . The hot-water supply return pipe  26  connects the outflow side pipe  23  and the inflow side pipe  22 . In the hot-water supply return pipe  26 , the circulation pump  45  for circulating the hot-water, the circulation flow rate sensor  47  for detecting a flow rate of warm water introduced into the circulation pump  45 , and the check valve  46  for flowing the hot-water in only one direction are arranged. The circulation pump  45  supplies the hot-water using a motor not shown as a driving source, and can be configured by, for example, a known spiral pump. 
     The hot-water supply device  100  of the embodiment is a hot-water supply device with a built-in circulation pump, and can suck the hot-water of the outflow side pipe  23  and discharge the hot-water to a side of the inflow side pipe  22  by an operation of the circulation pump  45 . As a result, even if the hot-water supply tap  60  is closed, a circulating heating path (hereinafter, also called “circulation path”) which passes through the heat exchange portion  11  can be formed inside the hot-water supply device  100  by circulating the hot-water heated by the heat exchange portion  11  from the outflow side pipe  23  to the inflow side pipe  22 . At this time, by the check valve  46 , during the operation of the circulation pump  45 , a back flow from the side of the inflow side pipe  22  to a side of the outflow side pipe  23  can be prevented, and the circulation path can be formed. 
     Next, the actions of the hot-water supply device  100  are described. The hot-water supply device  100  includes normal hot-water supply operation for starting combustion in response to a hot-water outlet request and the instant hot-water operation for generating hot-water at a set temperature in advance before the hot-water outlet request. 
     The normal hot-water supply operation of the hot-water supply device  100  is described below. The hot-water supply operation is an operation for supplying the hot-water from the hot-water dispenser  70  to the hot-water supply tap  60 . When the hot-water supply tap  60  is opened, a path P 0  is formed through which the hot-water (the low-temperature water) flows into the inflow side pipe  22  due to the water pressure of the water supply source (not shown). The low-temperature water inflowing by the path P 0  is branched into a path P 1  through which the low-temperature water is input to the heat exchange portion  11  by the inflow side pipe  22  and a path P 2  through which the low-temperature water is output without being heated to the outflow side pipe  23  passing through the bypass pipe  25 . As described above, a flow rate ratio of the paths P 1  and P 2  is controlled by the opening degree regulation of the bypass flow rate regulating valve  44  performed by the controller  50 . 
     The hot-water (the low-temperature water) which is input to the heat exchange portion  11  by the path P 1  is heated by the heat exchange portion  11 . The hot-water (high temperature water) which was heated by the heat exchange portion  11  is output to the outflow side pipe  23  by a path P 3 . In the outflow side pipe  23 , the low-temperature water of the path P 2  and the high temperature water of the path P 3  are mixed in the connection portion  24  with the bypass pipe  25  and then supplied to the hot-water supply tap  60  by a path P 4 . That is, the paths P 3  and P 4  in  FIG. 1  form a “hot-water supply path” for supplying the hot-water from the hot-water dispenser  70  to the hot-water supply tap  60 . 
     Furthermore, when the instant hot-water operation is stopped, the circulation pump  45  is stopped, and thus the hot-water of the path P 4  is not introduced into the hot-water supply return pipe  26 . Furthermore, due to the arrangement of the check valve  46 , flow of the hot-water is not generated in a direction from the side of the inflow side pipe  22  to the side of the hot-water supply return pipe  26 , either. 
     Next, the instant hot-water operation of the hot-water supply device  100  is described. The instant hot-water operation is an operation for circulating and heating the hot-water remaining in the hot-water supply path. When the instant hot-water operation is started, the controller  50  activates the circulation pump  45 , thereby forming a path Pa through which the hot-water from the heat exchange portion  11  is sucked to the circulation pump  45  through the outflow side pipe  23  and a path Pb through which the hot-water discharged from the circulation pump  45  is introduced to the heat exchange portion  11  through the inflow side pipe  22 . Furthermore, when the instant hot-water operation is stopped, the controller  50  can detect, based on the detection value of the water supply side flow rate sensor  43  and/or the hot-water side flow rate sensor  28 , that the hot-water supply operation is carried out. 
     Furthermore, the controller  50  executes combustion operation performed by the hot-water dispenser  70  until a temperature of the hot-water flowing through the hot-water supply return pipe  26 , for example, the hot-water temperature Tw detected by the hot-water outlet temperature sensor  42  reaches a target temperature of the instant hot-water operation. The target temperature is set to a value equal to or close to the hot-water supply set temperature. Besides, if the hot-water outlet temperature reaches the target temperature, the circulation pump  45  and the combustion operation are stopped and thereby the instant hot-water operation is finished. That is, the paths Pa and Pb in  FIG. 1  form a “circulation path” for carrying out the instant hot-water operation for circulating and heating the hot-water remaining in the hot-water supply path. Furthermore, in the instant hot-water operation, the controller  50  can confirm, from the detection value of the circulation flow rate sensor  47 , that the hot-water flows through the hot-water supply return pipe  26 , that is, the instant hot-water operation is carried out. 
     In the instant hot-water operation, when the hot-water supply tap  60  is closed, the hot-water circulates in the “circulation path” consisting of the paths Pa and Pb, and thus the flow rate detected by the hot-water side flow rate sensor  28  and the flow rate detected by the circulation flow rate sensor  47  are the same. 
     On the other hand, when the hot-water supply tap  60  is opened in the instant hot-water operation, one portion of the low-temperature water supplied from the path P 0  further flows into the inflow side pipe  22 , and thus the flow rate detected by the hot-water side flow rate sensor  28  increases. An increase amount of the hot-water flowing in the outflow side pipe  23  is the same as the hot-water supplied from the hot-water supply tap  60 , and thus the flow rate detected by the circulation flow rate sensor  47  does not change. Therefore, when the hot-water supply tap  60  is opened in the instant hot-water operation, the detection value of the hot-water side flow rate sensor  28  is greater than the detection value of the circulation flow rate sensor  47 . 
     The controller  50  detects the supply of the hot-water from the hot-water supply tap  60  from a difference between the detection values of the hot-water side flow rate sensor  28  and the circulation flow rate sensor  47 . The hot-water side flow rate sensor  28  and the circulation flow rate sensor  47  correspond to one example of a “flow rate sensor”. Furthermore, due to the arrangement of the check valve  48 , flow of the hot-water from the circulation path to the paths P 0 , P 2  of the water supply side is not generated. 
       FIG. 2  is a function block diagram for illustrating a control configuration of the hot-water supply device  100  according to the embodiment. 
     With reference to  FIG. 2 , the controller  50  control the actions of the hot-water supply device  100 . The controller  50  receives the detection values of the hot-water side flow rate sensor  28 , the circulation flow rate sensor  47 , the water inlet temperature sensor  27  and the hot-water outlet temperature sensor  42 . The controller  50  controls, based on the received detection values of various sensors, a burner  5 , the blower  10 , the circulation pump  45 , the bypass flow rate regulating valve  44  and the flow rate regulating valve  41 . 
     The controller  50  is configured by a microcomputer and incorporates a CPU (Central Processing Unit) and an input/output interface which are not shown, a clock  501  and a memory  502 . 
     The clock  501  repeatedly measures unit times. In the specification, the “unit times” are times in which a pattern of hot-water usage of a user makes a round, for example, at least one of one day, one week, one month and one year. This is because it is assumed that the same action is repeated basically every 24 hours, for example, the user washes face every morning and takes a bath every night. Therefore, if the unit time of the clock  501  is one day, reservation can be carried out in a manner that the instant hot-water operation is performed in the same time zone every day on the basis of the unit time of the clock  501 . Furthermore, it is also assumed that the same action is repeated every week, for example, the user goes home late and takes a bath around 9 o&#39;clock at night on weekdays (Monday to Friday), but takes a bath early around 7 o&#39;clock at night on Saturday and Sunday. Similarly, it is also assumed that the same action is repeated in one month and one year. The clock  501  corresponds to one example of a “first clock”. 
     The clock  501  can be configured by a real-time clock built-in the microcomputer. The real-time clock is powered from an auxiliary power supply, and thus an actual time can be reflected even if a power supply is cut off. In addition, the clock  501  may be linked to a GPS (Global Positioning System) so that a time difference or a summer time can be reflected in the time of the clock  501 . 
     The memory  502  is configured to be capable of keeping information input to the controller  50  and using the kept information in the controller  50  or outputting the kept information from the controller  50 . The memory  502  is configured by, for example, a volatile memory and a non-volatile memory. The memory  502  includes a primary memory  502 A and a usage memory  502 B. 
     A communication portion  18  has a communication function using a communication line  80 . The remote controller  8  is used for remotely operating each portion of the hot-water supply device  100  including the hot-water dispenser  70 . The remote controller  8  has an operation switch  82  and an operation switch  83 , a display portion  85 , a control portion  87 , and a communication portion  88 . Typically, the operation switch  82  and the operation switch  83  can be configured by a push button or a touch button. Typically, the display portion  85  can be configured by a liquid crystal panel and may be configured as a touch panel which can be operated by touching a screen. 
     The control portion  87  is configured by a microcomputer and incorporates a CPU (Central Processing Unit) and an input/output interface which are not shown, a memory  872  and a clock  871 . The memory  872  is configured to be capable of keeping information input into the control portion  87  and outputting the kept information from the control portion  87 . The memory  872  is configured by, for example, a non-volatile memory. The clock  871  is included for measuring the current time. 
     The communication portion  88  is connected to the hot-water supply device  100  via the communication line  80 . The hot-water supply device  100  and the remote controller  8  can communicate with one another bi-directionally using the communication portions  18 ,  88  and the communication line  80 . 
     In a conventional hot-water supply device, in order to effectively carry out instant hot-water operation, the user needs to specify, in view of time zones in which the user uses the hot-water supplied from the hot-water supply tap  60  by hot-water supply operation, time zones in which the instant hot-water operation is to be carried out. In the following description, using the hot-water supplied from the hot-water supply tap  60  is also called using hot-water or simply called hot-water usage. Specifically, for example, the user needs to carry out, on a screen of a remote controller, operations of setting reservation of time zones in which the instant hot-water operation is required and cancelling reservation of time zones not wanted, and there is concern of wasting time of the user. Furthermore, this manual reservation of the instant hot-water operation by the user requires to be re-reserved each time according to lifestyle, family structure and seasonal changes of the user, and there is concern of bringing inconvenience to the user. 
     On the other hand, in patent literature 1, a hot-water supply control system is disclosed in which a sensor for detecting movement of the user which is considered to relate to hot-water outlet is installed at home, and heat insulation circulation operation is turned on/off based on detection values of the sensor. However, in this configuration, there is possibility that the movement detected by the sensor may include movement which actually does not relate to the hot-water usage, and there is a risk that because the hot-water supply control system mistakenly turns on/off the heat insulation circulation operation, user comfort is impaired or energy consumption is wasted. 
     The hot-water supply device  100  according to the embodiment of the application is configured to automatically detect the time zones in which the user uses the hot-water supply, reserve the instant hot-water operation based on the time zones, and execute the instant hot-water operation according to the reservation. 
     Specifically, in the hot-water supply device  100 , during both the execution and stop of the instant hot-water operation, the controller  50  detects the usage of the hot-water supply based on the detection values of three flow rate sensors. Furthermore, the controller  50  stores, in the primary memory  502 A, the time zones in which the usage of the hot-water supply is detected. In addition, the controller  50  sets, based on the storage of the time zones in which the usage of the hot-water supply is detected (hereinafter, also called hot-water supply storage), time zones in which the instant hot-water operation is reserved, and stores the reservation of the instant hot-water operation (hereinafter, also called instant hot-water reservation) in the usage memory  502 B. Furthermore, the controller  50  carries out the instant hot-water operation based on the instant hot-water reservation. Furthermore, the controller  50  can detect, based on differences of the detection values of a plurality of flow rate sensors, the usage of the hot-water supply during the execution of the instant hot-water operation (during forming of the circulation path), and thus maintain a function of reserving the time zones in which the instant hot-water operation is performed based on the hot-water supply storage even during the execution of the instant hot-water operation. 
     Accordingly, in the time zones in which the user uses the hot-water supply on a daily basis, the instant hot-water operation is reserved automatically, and the instant hot-water operation is executed according to the instant hot-water reservation, and thus the user comfort is improved. Conversely, in the time zones in which the user does not use the hot-water supply, the instant hot-water reserve is cancelled automatically, and thus unnecessary instant hot-water operation is prevented, and energy saving is improved. Therefore, the hot-water supply device  100  can achieve both user comfort and energy saving. 
       FIG. 3  is a diagram illustrating setting of instant hot-water reservation based on hot-water supply storage in unit times (days). With reference to  FIG. 3 , the controller  50  includes the primary memory  502 A and the usage memory  502 B. In  FIG. 3 , the unit time is, for example, one day (24 hours). In  FIG. 3 , a first unit time and a second unit time are arbitrary consecutive unit times. The time zones are times set by dividing the unit times and have, for example, a length of 30 minutes or one hour. In each of time zones  1 -N1 of the first and second unit times, times in which the hot-water supply is used are stored in the primary memory  502 A. In addition, reservation time zones of the instant hot-water operation of the second and third unit times which are set based on the time zones in which the hot-water usage is detected are stored in the usage memory  502 B. Details thereof are described below. 
     The controller  50  detects, for each unit time, based on detection signals of the water supply side flow rate sensor  43 , the hot-water side flow rate sensor  28  and the circulation flow rate sensor  47 , the time zones in which the hot-water supply operation is carried out. 
     Specifically, the controller  50  calculates, on the basis of the time of the clock  501 , the times (hot-water supply times) in which the hot-water supply operation is detected. Besides, the controller  50  determines that the hot-water supply is used when the hot-water supply operation has continued for a predefined time t 3  or longer, and stores the hot-water supply times in the primary memory  502 A. Hereinafter, the predefined time t 3  is also called a “determination time”. By setting the determination time for determining the hot-water usage in this way, short-time usage of the hot-water (for example, when washing hands for a short time), in which the need for hot water is not so high for the user, may not be reflected in the primary memory  502 A, and as a result, the short-time usage of the hot-water instant may not be reflected in the reservation of the hot-water operation, either. In this way, the instant hot-water operation can be carried out only corresponding to a case in which the need for hot water is high for the user, that is, the hot-water is used for a certain time or longer (for example, one shower), and thus the user comfort can be ensured, and the energy consumption can be suppressed. 
     The controller  50  further calculates a “total hot-water supply time” obtained by adding the hot-water supply times stored in the primary memory  502 A for each time zone. The controller  50  determines that, when the total hot-water supply time is equal to or greater than a first reference value t 1  in a certain time zone, the hot-water supply operation is carried out in the time zone. The first reference value t 1  is, for example three seconds to five minutes. 
     Next, the controller  50  reserves, based on the time zones in which the hot-water supply operation is carried out in the first unit time, time zones in which the instant hot-water operation is to be carried out in the second unit time. Specifically, the controller  50  reserves the instant hot-water operation by storing, in the usage memory  502 B, the time zones of the second unit time which are the same as the time zones in which it is determined that the hot-water supply operation is carried out in the first unit time (see an arrow  64 ). Furthermore, the controller  50  controls, in the second unit time, each portion of the hot-water supply device  100  to carry out the instant hot-water operation based on the instant hot-water reservation (see an arrow  65 ). Therefore, in time zones (in  FIG. 3 , time zones  2  and  4 ; for example, a time zone of bathing) in which the user uses the hot-water supply for a relatively longer time, the instant hot-water operation is also automatically carried out the next day, and thus the user can immediately use hot-water at an appropriate temperature in the time zones. 
     In addition, the controller  50  reserves the instant hot-water operation in a manner that the instant hot-water operation is carried out from a moment earlier by a predefined time t 2  than the time zones in the second unit time which are the same as the time zones in the first unit time in which it is determined that the hot-water supply operation is carried out (a preheat function). Hereinafter, the time t 2  is also called the “preheat time”. The preheat function can immediately provide hot-water at a preferable temperature even when the user uses the hot-water supply at the same time as or immediately after a start moment of the time zones in which the hot-water supply is used. The preheat time t 2  corresponds to one example of a “first reference time”. The preheat time t 2  is, for example, 5-15 minutes. 
     In addition, even when the hot-water supply is not used in the time zones in which the instant hot-water operation is reserved in the second unit time, the controller  50  maintains the reservation of the instant hot-water operation of the time zones (for example, the time zone  2  in  FIG. 3 ). This is a control in view of a case in which movement of using the hot-water supply is stopped only for a short term (for example, 1-3 days) due to circumstances of the user. In this short-term disuse of the hot-water supply, for example, a case in which bathing is not performed for one day due to the absence of the user is considered. In this case, it is considered that keeping a state in which the instant hot-water operation can also be performed the next day without cancelling the instant hot-water reservation is desirable for the user. 
     On the other hand, the controller  50  cancels the reservation of the instant hot-water operation if the disuse of the hot-water supply continues for predefined days or longer. This is because it is considered desirable to cancel the instant hot-water reserve when, for example, the hot-water supply is not used for a moderate or long term (for example, about three or four days) in the time zones in which the hot-water supply is used until now due to a change of a life pattern of the user. In this life pattern change, for example, a change is considered that the user takes a bath in the morning and evening in the hot season but quits the bath in the morning and only takes a bath in the evening when it gets cooler. 
     In order to cope with both the short-term disuse of the hot-water supply and the moderate or long-term change of the life pattern, a configuration in which the instant hot-water reserve is cancelled when it is confirmed that the hot-water supply is not used for several consecutive days in the time zones in which the hot-water supply is used until now is desirable. Specifically, when the total hot-water supply time in a certain time zone is less than a second reference value t 4  in a plurality of consecutive unit times, it is stored in the usage memory  502 B that the instant hot-water operation is not to be carried out in the same time zone in the next day. In other words, the instant hot-water reserve for the same time zone in the next day is cancelled. If configured in this way, in the instant hot-water reservation, the short-term movement change of the user is not reflected, and the moderate or-long-term life pattern change can be reflected. 
       FIG. 4  is a diagram illustrating the cancellation of the instant hot-water reservation based on the hot-water supply storage in the unit times (days). Specifically, an example is shown in which reservation of the instant hot-water operation of a time zone is cancelled for the time zone (the time zone  2  in  FIG. 4 ) in which the hot-water supply is used and the instant hot-water operation is reserved in the first unit time when the hot-water supply is not used in the same time zones of M consecutive unit times following other unit times. In  FIG. 4 , it is set that M=3. 
     With reference to  FIG. 4 , the hot-water supply is used in the time zone  2  of the first unit time, and thus the instant hot-water operation in the time zone  2  in the second unit time is reserved. 
     In the time zone  2  of the second unit time, the hot-water supply is not used. However, in the time zone  2  of the second unit time, the number of times the hot water supply is not used consecutively is one, and thus in the time zone  2  of the third unit time, the reservation of the instant hot-water operation is maintained. 
     In the time zone  2  of the third unit time, the hot-water supply is not used. However, in the time zone  2  of the third unit time, the number of times the hot water supply is not used consecutively is two, and thus the reservation of the instant hot-water operation in the time zone  2  of the fourth unit time is maintained. 
     In the time zone  2  of the fourth unit time, the hot-water supply is not used. In addition, in the time zone  2  of the fourth unit time, the number of times the hot water supply is not used consecutively is three. Therefore, the reservation of the instant hot-water operation in the time zone  2  of the fifth unit time is cancelled. 
     In other words, the controller  50  does not reserve the instant hot-water operation in the second time zone of the fifth unit time, when the total hot-water supply time of the second time zone in which the instant hot-water operation is reserved is less than the second reference value in consecutive M (in  FIG. 4 , three times) unit times before the fourth unit time and in the fourth unit time. 
     Furthermore, in the example of  FIG. 4 , a configuration in which when the hot-water supply is not used in the same time zone in the consecutive M unit times, the reservation of the instant hot-water operation of the time zone is cancelled is described, but the following configuration is also possible in which when the hot-water supply is not used in the same time zone in N or more unit times of the consecutive M unit times, the reservation of the instant hot-water operation of the time zone is cancelled. Here, N is an integer ranging from  2  to M. 
     The instant hot-water reservation which is shown in  FIG. 3  and  FIG. 4  and based on the time of the hot-water usage is carried out for the predefined number of times in the unit times. For example, in  FIG. 5 , a configuration in which the instant hot-water operation of the second unit time is reserved based on storage of the hot-water usage of the first unit time for a predetermined moment (a reservation determining moment t 0 , for example, 0 a.m.) once a day is illustrated. The reservation determining moment t 0  may be set to a moment at which the unit time is switched (see  FIG. 3 ). Timing at which the instant hot-water operation is reserved is not limited to the above example and may be configured, for example, in a manner that the instant hot-water operation is reserved at any time according to determination of the hot-water usage. 
     In addition, here, the hot-water supply time in each time zone is set as an amount serving as a reference for setting the reservation of the instant hot-water operation, but the disclosure is not limited hereto. The controller  50  may detect at least one of supply time, the number of times of supply and supply volume of the hot-water from the hot-water supply path for each time zone, and detect a time zone in which at least one of the supply time, the number of times of supply and the supply volume is equal to or greater than a corresponding first reference value t 1  as a time zone in which the hot-water supply operation is carried out. 
     Similarly, the hot-water supply time in each time zone is set as an amount serving as a reference for cancelling the reservation of the instant hot-water operation, but the disclosure is not limited hereto. The controller  50  may detect at least one of the supply time, the number of times of supply and the supply volume of the hot-water from the hot-water supply path for each time zone, and does not reserve the instant hot-water operation in the second time zone of the second unit time when at least one of the supply time, the number of times of supply and the supply volume of the hot-water in the second time zone in which the instant hot-water operation is reserved is less than a corresponding second reference value in a plurality of consecutive unit times before the first unit time. 
     The preheat time t 2  can be set based on at least one of environmental condition and installation condition of the hot-water supply device. The preheat time t 2  may change length by learning. Specifically, a time from the start of the instant hot-water operation to the time when a temperature of the hot-water outlet temperature sensor  42  reaches a set temperature is measured, and the measured value is reflected in the value of the preheat time t 2 . For example, when an installation place of the hot-water supply device  100  is a cold land, or when a pipe length and a pipe thickness of the circulation path are great, the time from the start of the instant hot-water operation to the time when the set temperature is reached becomes longer, and thus the preheat time t 2  also becomes longer. By regulating the preheat time t 2 , the hot-water at an appropriate temperature can be supplied even if the user uses hot water immediately after the start of the time zones in which the instant hot-water operation is reserved. In addition, it is considered that the time from the start of the instant hot-water operation to the time when the set temperature is reached also changes with season (particularly temperature condition), and thus the preheat time t 2  can be automatically changed corresponding to the change in season (for example, once per month). 
     In addition, the determination time t 3  may be variable and the user can regulate strength of reflecting the usage of the hot-water supply of the user in the reservation of the instant hot-water operation. In this way, the user can enjoy the instant hot-water operation matching usage situation and/or preference of hot-water supply of himself. For example, if usage of the hot-water supply in less than one second is very often and these cases are to be ignored, the determination time t 3  may set to one second. In addition, the determination time t 3  may be shortened if emphasis is put on the comfort of producing hot water at an appropriate temperature each time rather than saving energy consumption. 
     When the hot-water supply device  100  is shipped from the factory, instant hot-water reservation in a predefined pattern may be pre-set in the controller  50 . In this case, at the time of construction of the hot-water supply device  100 , it is possible that whether to use the pre-set instant hot-water reservation pattern or to turn on 24-hour instant hot-water reservation can be selected. 
     As described above, in the hot-water supply device  100  according to the embodiment, the controller  50  automatically detects the time zones in one day in which the hot-water supply is used and reflects the time zones in the reservation of the instant hot-water operation of the next day. Therefore, in the hot-water supply device  100 , even if the user does not manually carry out the instant hot-water reservation, the instant hot-water operation matching the usage situation of the user can be achieved. 
     In addition, by setting the determination time t 3  for determining the usage of the hot-water supply times, strength to reflect the hot-water usage in the instant hot-water reservation can be regulated. Accordingly, the user can select whether to save the energy consumption or to give priority to the comfort of immediately producing the hot-water at an appropriate temperature. 
     Furthermore, the embodiment can be applied not only to a case that the hot-water supply device  100  is installed alone as shown in  FIG. 1 , but also to a hot-water dispenser which is connected and installed. At this time, the learning of the instant hot-water operation can be shared among controllers of each hot-water dispenser. 
     Control for executing the instant hot-water operation on the basis of the hot-water supply time zones is described below using the flowcharts of  FIGS. 5-9 . 
       FIG. 5  is a flowchart for illustrating a setting method of the preheat time. The flowchart of  FIG. 5  is repeatedly executed by the controller  50  at a predetermined timing. 
     With reference to  FIG. 5 , the controller  50  determines, in step S 51 , whether or not the instant hot-water operation is carried out. The controller  50  returns the processing to a main routine when the instant hot-water operation is not carried out (determination of “NO” in S 51 ). 
     On the other hand, the controller  50  stores values of the clock  501  in step S 52  when the instant hot-water operation is carried out (determination of “YES” in S 51 ). Next, the controller  50  determines, in step S 53 , whether the hot-water temperature Tw detected by the hot-water outlet temperature sensor  42  is equal to or higher than the predefined reference temperature T 2 . The controller  50  repeats step S 53  when the hot-water temperature Tw is lower than the reference temperature T 2  (determination of “NO” in S 53 ). 
     On the other hand, the controller  50  stores the values of the clock  501  in step S 54  when the hot-water temperature Tw is equal to or higher than the reference temperature T 2  (determination of “YES” in S 53 ). Next, the controller  50  calculates and stores, in step S 55 , a reaching time t 20  in which the hot-water temperature Tw reaches the reference temperature T 2  from the start of the instant hot-water operation. 
     Furthermore, the controller  50  reflects, in step S 56 , values of the reaching time t 20  in the preheat time t 2  and returns the processing to the main routine. As a method for reflecting the values of the reaching time t 20  in the preheat time t 2 , for example, there is a method in which the preheat time t 2  is set to an average of the values of the reaching time t 20  when the instant hot-water operation is started for predefined number of times in the past. 
     As described above, the hot-water supply device  100  according to the embodiment automatically learns the preheat time t 2  which is corresponding to the environmental conditions and the installation conditions and necessary for temperature rise of the hot-water supply path, and executes the preheat function. Therefore, the user can use hot water at an appropriate temperature as needed while avoiding unnecessary energy consumption. 
       FIG. 6  is a flowchart for illustrating a storage method of the hot-water supply time. The flowchart of  FIG. 6  is repeatedly executed by the controller  50  at a predefined timing. 
     With reference to  FIG. 6 , in step S 01 , the controller  50  determines, based on the detection values of the water supply side flow rate sensor  43 , the hot-water side flow rate sensor  28  and the circulation flow rate sensor  47 , whether the hot-water supply operation is carried out. The controller  50  returns the processing to the main routine when the hot-water supply operation is not carried out (determination of “NO” in S 01 ). 
     The controller  50  stores values of the clock  501  in step S 02  when the hot-water supply operation is carried out (determination of “YES” in S 01 ). 
     The controller  50  determines, in step S 03 , whether the hot-water supply operation is stopped. The controller  50  repeats step S 03  when the hot-water supply operation is carried out (determination of “NO” in S 03 ). The controller  50  stores values of the clock  501  in step S 04  when the hot-water supply operation is stopped (determination of “YES” in S 03 ). 
     Furthermore, the controller  50  calculates, in step S 05 , the time from the execution of the hot water supply operation to the stop of the hot water supply operation, that is, the hot-water supply time. Next, the controller  50  determines, in step S 06 , whether the hot-water supply time is equal to or greater than the determination time t 3 . The controller  50  returns the processing to the main routine when the hot-water supply time is less than the determination time t 3  (determination of “NO” in S 06 ). 
     When the hot-water supply time is equal to or greater than the determination time t 3  (determination of “YES” in S 06 ), the controller  50  stores the calculated hot-water supply times in the primary memory  502 A in step S 07  and returns the processing to the main routine. 
     As described above, the hot-water supply device  100  according to the embodiment automatically detects the hot-water supply time and stores the hot-water supply time in the primary memory  502 A. 
       FIG. 7  is a flowchart for illustrating a reservation method of the instant hot-water operation. The flowchart of  FIG. 7  is repeatedly executed by the controller  50  at a predefined timing. 
     With reference to  FIG. 7 , the controller  50  determines, in step S 10 , whether it is the predefined reservation determining moment t 0  (for example, 0 a.m. every day). Furthermore, in  FIG. 7 , the reservation determining moment t 0  is a switching moment between arbitrary consecutive first and second unit times. The controller  50  returns the processing to the main routine when it is not the reservation determining moment t 0  (determination of “NO” in S 10 ). 
     When it is the reservation determining moment t 0  (determination of “YES” in S 10 ), the controller  50  sets n=1 in step S 11  when the number of the time zone is n (n is a natural number satisfying 1≤n≤N1). The controller  50  determines, in the following step S 12 , whether there is instant hot-water reservation of the time zone n in the first unit time. 
     When there is instant hot-water reservation of the time zone n in the first unit time (determination of “YES” in S 12 ), in step S 13 , the controller  50  determines whether the total hot-water supply time of the time zone n is equal to or greater than the second reference value t 4  in consecutive M (M is a natural number equal to or greater than 2) unit times (that is, M days here) before the first unit time. When the total hot-water supply time of the time zone n of the consecutive M unit times before the first unit time is less than the second reference value t 4  (determination of “NO” in S 13 ), in step S 14 , the controller  50  sets the reservation so as not to carry out instant hot-water operation in the time zone n of the second unit time (cancel the instant hot-water reservation). 
     On the other hand, when the total hot-water supply time of the time zone n is equal to or greater than the second reference value t 4  in at least one of the consecutive M unit times before the first unit time (determination of “YES” in S 13 ), in step S 15 , the controller  50  also maintains the instant hot-water reservation in the time zone n of the second unit time. 
     When there is no instant hot-water reservation in the time zone n of the first unit time (determination of “NO” in S 12 ), in step S 18 , the controller  50  determines whether the total hot-water supply time of the time zone n in the first unit time is equal to or greater than the first reference value t 1 . The controller  50  returns the processing to the main routine when the total hot-water supply time of the time zone n in the first unit time is less than the first reference value t 1  (determination of “NO” in S 18 ). 
     On the other hand, when the total hot-water supply time of the time zone n in the first unit time is equal to or greater than the first reference value t 1  (determination of “YES” in S 18 ), in step S 19 , the controller  50  determines whether there is instant hot-water reservation in the time zone n−1 of the second unit time. When there is instant hot-water reservation in the time zone n−1 of the second unit time (determination of “YES” in S 19 ), in step S 20 , the controller  50  sets the reservation so as to carry out the instant hot-water operation of the time zone n in the second unit time. On the other hand, when there is no instant hot-water reservation in the time zone n−1 of the second unit time (determination of “NO” in S 19 ), in step S 21 , the controller  50  sets the reservation so as to carry out the instant hot-water operation from a moment earlier by the preheat time t 2  than the time zone n in the second unit time until the end of the time zone n. 
     Following steps S 14 , S 15 , S 20 , S 21 , the controller  50  increases the value of n by one in step S 16  (sets n=n+1). In the following step S 17 , the controller  50  determines whether n is equal to N1 (the number of the last time zone in each unit time) (whether n=N1). The controller  50  returns the processing to step S 12  when n is not equal to N1 (n=N1 is not satisfied) (determination of “NO” in S 17 ). On the other hand, the controller  50  returns the processing to the main routine when n is equal to N1 (n=N1) (determination of “YES” in S 17 ). 
     As described above, in the hot-water supply device  100  according to the embodiment, the controller  50  reserves, on the basis of the storage in the primary memory  502 A of the time zones in an arbitrary unit time in which the hot-water supply operation is carried out, the time zones of the following unit time in which instant hot-water operation is carried out. 
       FIG. 8  is a flowchart for illustrating an execution method of the instant hot-water operation. The flowchart of  FIG. 8  is repeatedly executed by the controller  50  at a predefined timing. 
     The controller  50  determines whether there is instant hot-water reservation in step S 31 . When there is instant hot-water reservation (determination of “YES” in S 31 ), in step S 32 , the controller  50  determines whether the hot-water supply device  100  is in the instant hot-water operation. When the hot-water supply device  100  is in the instant hot-water operation (determination of “YES” in S 32 ), in step S 33 , the controller  50  determines whether the hot-water temperature Tw detected by the hot-water outlet temperature sensor  42  is equal to or higher than the predefined reference temperature T 2 . When the hot-water temperature Tw is equal to or higher than the reference temperature T 2  (determination of “YES” in S 33 ), in step S 34 , the controller  50  stops the instant hot-water operation and returns the processing to the main routine. 
     On the other hand, when the hot-water temperature Tw is lower than the reference temperature T 2  (determination of “NO” in S 33 ), in step S 35 , the controller  50  maintains the instant hot-water operation and returns the processing to the main routine. 
     In addition, when the hot-water supply device  100  is not in the instant hot-water operation (determination of “NO” in S 32 ), in step S 36 , the controller  50  determines whether the hot-water temperature Tw is lower than the predefined reference temperature T 1 . Here, the reference temperature T 1  is a temperature equal to or lower than the reference temperature T 2 . When the hot-water temperature Tw is lower than the reference temperature T 1  (determination of “YES” in S 36 ), in step S 37 , the controller  50  starts the instant hot-water operation and returns the processing to the main routine. 
     On the other hand, when the hot-water temperature Tw is equal to or higher than the reference temperature T 1  (determination of “NO” in S 36 ), in step S 38 , the controller  50  maintains the instant hot-water operation and returns the processing to the main routine. 
     In addition, when there is no instant hot-water reservation (determination of “NO” in S 31 ), in step S 39 , the controller  50  determines whether the hot-water supply device  100  is in the instant hot-water operation. When the hot-water supply device  100  is in the instant hot-water operation (determination of “YES” in S 39 ), in step S 40 , the controller  50  stops the instant hot-water operation and returns the processing to the main routine. Furthermore, the above state without instant hot-water reservation and in the instant hot-water operation occurs immediately after the time zone n+1, for example, when there is instant hot-water reservation and instant hot-water operation is carried out in a certain time zone n (n is a natural number), but there is no instant hot-water reservation in a time zone n+1 following the time zone. At the time of this state, the controller  50  ends the instant hot-water operation following the time zone n by step S 31 , steps S 39  and S 40 . 
     On the other hand, the controller  50  returns the processing to the main routine when the hot-water supply device  100  is not in the instant hot-water operation (determination of “NO” in S 39 ). 
     As described above, the hot-water supply device  100  according to the embodiment controls the instant hot-water operation based on the instant hot-water reservation. 
     Other Configuration Examples 
     (1) About Unit Times 
       FIG. 9  is a diagram illustrating hot-water supply storage and instant hot-water reservation in unit times (weeks). As described above, the unit times are times in which the pattern of the hot-water usage of the user makes a round, and the time unit of one week is shown in the example of  FIG. 9 . With reference to  FIG. 9 , the unit times (weeks) are configured by seven unit times (days). In addition, the hot-water supply time of each time zone is stored in the primary memory  502 A for each unit time (day). Based on the storage of the time zones in which the hot-water supply operation is carried out for each unit time (day), reservation of time zones of instant hot-water operation in the next week is stored in the usage memory  502 B for each unit time (day). That is, the instant hot-water operation is reserved for every day of the week so that, for example, usage time zones of hot-water supply on Monday of this week are reserved for instant hot-water at the same time zones on Monday of the next week (see arrow  66 ). 
     At the time of factory shipment, there is no data indicating time zones of the hot-water supply operation until now in the primary memory  502 A, and thus the time zones of the reservation of the instant hot-water operation cannot be stored in the usage memory  502 B based on the data. Therefore, as described above, in the usage memory  502 B at the time of factory shipment, instant hot-water reservation with a pre-set pattern or a 24-hour-on instant hot-water reservation may be set. In addition, there is a case in which it is considered that compared with the pre-set pattern or 24-hour-on pattern, an instant hot-water pattern of the same day in the next week based on a hot-water usage pattern on the first day of the user is more consistent with the hot-water usage on the second day of the user (that is, a case in which it is considered that with respect to the hot-water usage pattern, the usage on the first day and the usage on the second day are more consistent compared with the usage on the first day and the pre-set instant hot-water reserve pattern). In this case, the instant hot-water reserve pattern of the second day may be configured by copying the instant hot-water pattern of the same day of the next week based on the hot-water usage pattern on the first day (see an arrow  67 ). 
     (2) About Synchronization of Clocks 
       FIG. 10  is a sequence diagram for illustrating synchronization of a clock of a remote controller with a clock of a controller. With reference to  FIG. 10 , when the remote controller  8  is activated, a signal indicating the activation is transmitted to the controller  50 . When receiving the signal, the controller  50  transmits the time of the clock  501  to the remote controller  8  via the communication line  80 . When receiving the time of the clock  501 , the remote controller  8  rewrites the time of the clock  871  with the time of the clock  501 . That is, the remote controller  8  can synchronize the time of the clock  871  with the received time of the clock  501 . 
     In this way, the user does not need to manually set the time of the clock  871 , and usage of the remote controller becomes easier. 
     As described above, in the hot-water supply device according to the embodiment of the disclosure, the usage of the hot-water supply of the user during the instant hot-water operation and during stopping of the instant hot-water operation can be detected by the controller and automatically reflected in the reservation of the instant hot-water operation. That is, the hot-water supply device which achieves both energy saving and user comfort can be provided by automatically reserving so that the instant hot-water operation is carried out in the time zones in which the hot-water supply is used in the past. 
     The embodiment disclosed here should be considered as illustrative instead of restrictive in all points. The scope of the disclosure is not shown by the above description but by the scope of claims and is intended to include the meaning equivalent to the scope of the claims and all changes within the scope.