JP6428364B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water apparatus in which a fluid circulated in one circulation path is indirectly heated by liquid-liquid heat exchange using a heat medium circulated and supplied in the other circulation path as a heat source. The present invention relates to a control technique that can detect the circulating flow rate of the fluid circulated in the one circulation path by a control process without using a detection means for directly detecting the above.

  In order to detect the circulating flow rate of a fluid without using a flow sensor, the applicant of the present application has proposed a technique that can be detected by control processing in Patent Document 1 below. This is because in a 1-can 2-water-type hot water bath with hot water heater, hot water in the bathtub circulated in the recirculation circuit is directly heated by the combustion burner while passing through the heat exchanger in the can body. The circulating flow rate of the hot water circulated through the circulation path can be detected. Specifically, hot water in the bathtub is circulated between the reheating heat exchanger heated by the combustion burner, and hot water heated by reheating in the reheating heat exchanger is supplied to the bathtub. After the recirculation heating that is performed, the processing is started to detect the circulation flow rate. That is, although the reheating heating by the combustion burner is stopped, the circulation itself in the reheating circulation path is continued without being interrupted. Then, after the reheating heating is stopped, the descent time value required for the temperature of the hot water supplied to the bathtub to pass through the reheating heat exchanger to decrease by a predetermined set temperature difference is detected, and the value is detected from a predetermined relationship table. The circulation flow value corresponding to the descent time value is calculated. Such a relationship table is a table or a relational expression that is obtained in advance by a test or the like to obtain a relationship between the descent time and the circulation flow rate.

Japanese Patent No. 5326650

  By the way, there is known a hot water apparatus configured in a composite type having a hot water circulation type heating function in addition to a hot water supply function and a reheating function. In such a hot water apparatus, a hot water supply heat exchanger and a heating heat exchanger are heated by a combustion burner, and the heat medium heated by the heating heat exchanger is circulated as a heat source to an external heating terminal. At the same time as the supply, it is configured in a two-can three-water system so as to circulate and supply as a heat source to a liquid-liquid heat exchange type heat exchanger for reheating. In other words, the reheating heat exchanger is not directly heated by the combustion burner, but indirectly heated by using a heating circulating heat medium heated by the combustion burner and circulated as a heat source. ing.

  In order to detect the circulating flow rate of the circulating hot water in the bathtub passing through the heat exchanger for reheating, targeting the hot water device configured in such a two-can three-water channel type, the technique proposed in Patent Document 1 is used. Even if it is to be applied, there is a disadvantage that the circulating flow rate cannot be detected quickly and accurately. The reason for this is that if direct combustion heating is performed by a combustion burner, if the combustion operation of the combustion burner is stopped, the reheating heating stops immediately, and the circulating hot water passing through the reheating heat exchanger is stopped. For example, the temperature drops rapidly as shown in FIG. The technique proposed in the above-mentioned Patent Document 1 uses such a rapid temperature drop that suddenly changes from a temperature rise to a drop, and uses a fall time value (for example, Δτ1 or the like) required to drop by a predetermined temperature difference ΔT. By detecting Δτ2), the value of the circulation flow rate is obtained quickly and accurately. However, since the reheating heat exchanger in the case of the two-can three-water channel type is indirect heating by liquid-liquid heat exchange using a heat medium circulated as a heat source for heating as a heat source, the heat source for heating Even if the combustion burner for heating is stopped, the heated heating medium is circulated and supplied to the reheating heat exchanger through the pipe, so the heat supply to the reheating heat exchanger is not stopped. Moreover, since the supplied heat input also depends on the circulating flow rate on the heating side, it is unknown. Furthermore, even if the circulating supply of the heat medium to the reheating heat exchanger can be shut off, the reheating heat exchanger will be filled with the heat medium as the heat source for a while after the interruption. The heat transfer from the heat medium to the circulating hot water is continued. For this reason, the conversion point from the temperature rise to the temperature drop as in the one-can / two-water channel system does not appear clearly, and a rapid temperature drop does not occur, and the technique proposed in Patent Document 1 is applied as it is. However, a rapid and accurate detection of the circulation flow rate cannot be obtained.

  In the recirculation circuit for reheating and heating the hot water in the bathtub, for example, a device capable of directly detecting the circulation flow rate such as a normal water wheel type flow rate sensor is not installed, but by control. We are trying to grasp and detect this because it is not just a cost situation but the following background situation. In other words, the fluid circulated in the recirculation circuit is bathtub hot water, and hair is expected to be mixed in the bathtub hot water. It is not possible to detect the circulating flow rate directly. Even if the rated discharge flow rate of the circulation pump installed in the recirculation circuit is known, the recirculation flow rate in the recirculation circuit connecting the bathtub with the open water surface and the heat exchanger is It does not match the discharge flow rate, and the circulation flow rate cannot be grasped by the discharge flow rate of the circulation pump. Furthermore, the significance of grasping the circulation flow rate in the recirculation circuit is that, especially when there is remaining hot water in the bathtub, it takes time to grasp the amount of remaining hot water. In order to solve this problem, there is a situation in which quick and accurate detection (grasping) of the circulating flow rate in the recirculation circuit is a particularly important issue.

  The present invention has been made in view of such circumstances, and the object of the present invention is to detect the circulation flow rate in the circulation path even if the heating of the circulating fluid is based on indirect heating. It is an object of the present invention to provide a hot water apparatus which can be performed without using the direct detection means, and can detect the circulating flow rate quickly and accurately.

  In order to achieve the object, the present invention provides a first circulation path in which a heat medium heated by a heating source is circulated as a heat source, a second circulation path in which a fluid is circulated, and the second circulation. A heat exchanger for heat exchange heating of the fluid in the passage, and the heat exchanger is connected to the first circulation passage so that the heat medium can be circulated as a heat source, and the fluid is transferred to the heat medium. The following technical measures were taken for a hot water device configured to be heated indirectly. That is, return temperature detecting means for detecting the temperature of the return side fluid in the second circulation path at the upstream position in the circulation direction from the heat exchanger, and the first at the downstream position in the circulation direction from the heat exchanger. And a circulating flow rate detection processing unit for detecting the circulating flow rate of the fluid circulated through the second circulation path by a control process. . The circulating flow rate detection processing unit includes timer means for measuring an elapsed time value and a table storage unit for storing a predetermined relationship table. And as the relation table, the circulating flow rate of the fluid in the second circulation path and the forward side detected by the forward temperature detecting means from the time when the circulating supply of the heat medium to the heat exchanger is cut off It is assumed that the relationship with the descent time value required for the temperature of the fluid to drop to the set temperature value is set in advance. Further, as the circulating flow rate detection processing unit, the forward supply of the heat medium to the heat exchanger is interrupted while the second circulation path is maintained in a state where the fluid is circulating, and the forward temperature detection is performed. The temperature change of the forward fluid detected by the means is monitored, and the timer means determines the fall time value required for the temperature of the forward fluid to drop to the set temperature value from the time when the circulating supply of the heat medium is cut off. The measurement is performed, and based on the measured descent time value, the corresponding circulating flow rate value is determined and detected from the relation table. In addition, as the set temperature value, the return temperature is subtracted from the return temperature detected by the return temperature detection means with respect to the return temperature detected by the return temperature detection means at the time when the circulation of the heating medium is cut off. A value obtained by adding a value obtained by multiplying the difference between the return temperature and the return temperature by a predetermined ratio is set (claim 1).

  In the case of the present invention, since the fluid circulated in the second circulation path is indirectly heated in the heat exchanger using the heat medium circulated and supplied from the first circulation path as a heat source, the circulation supply of the heat medium is shut off. Even so, the heat medium that has been supplied and filled in the heat exchanger so far does not immediately decrease the temperature but gradually decreases the temperature. For such a temperature drop characteristic, from the previous temperature at the time when the circulation of the heat medium is cut off, to a set temperature value that is an intermediate temperature value between the forward temperature and the return temperature and is set using a predetermined ratio. Since the value of the circulation flow rate is obtained by measuring the fall time value required for the temperature drop and calculating from the relation table based on the measured fall time value, the second indirect heating as described above is performed. Even if the fluid is in the circulation path, the circulation flow rate value can be obtained accurately. Moreover, since the measurement of the descent time value until the temperature of the fluid in the second circulation path drops to the set temperature value is the main time necessary for the detection processing, the value of the circulation flow rate can be obtained quickly. . As described above, it is possible to quickly and accurately detect the circulating flow value of the fluid that is subjected to indirect heating only by measuring the descent time value without using the detection means that directly measures the circulating flow rate such as a flow rate sensor. become able to.

  In the hot water apparatus of the present invention, the first circulation path is constituted by a hot water circulation path for realizing a heating function by circulatingly supplying hot water as a heating medium between the heating terminal and the second circulation path. As the heat exchanger, the hot water is circulated and supplied as a heat source so that the hot water in the bathtub is circulated as a fluid between the heat exchanger and the bathtub. Can be constituted by a reheating heat exchanger for heating by liquid-liquid heat exchange. By doing in this way, the structure of the hot water device is specifically specified, for example, as a bath water heater with a hot water heating function that is configured in a two-can three-channel system by adding a hot water supply function. It can be clarified more. Further, in a recirculation circuit in which a direct flow rate detection means such as a flow sensor cannot be installed due to mixing of hair or the like, it becomes possible to accurately and quickly grasp the circulation flow rate for retreating.

  Moreover, in the hot water device of the present invention, the circulating flow rate detection processing unit may be configured to execute the circulating flow rate value detection process in a state where the remaining hot water is detected in the bathtub in the hot water filling control for the bathtub. (Claim 3). In this way, not only the circulating flow value can be detected using the remaining hot water, but also the circulating flow value can be obtained at this stage, thereby simplifying subsequent hot water filling control. Is also possible. For example, since the value of the circulating flow rate is grasped by the detection process by the circulating flow rate detection processing unit, the remaining hot water amount can be easily calculated using the value of the circulating flow rate, and as a result, the time required to complete the hot water filling control Can be significantly shortened compared to the conventional case.

  As described above, according to the hot water device of the present invention, the temperature value is an intermediate value between the return temperature and the return temperature from the return temperature at the time when the circulation of the heat medium from the first circulation path is cut off. The value of the circulation flow rate is obtained by measuring the descent time value required to drop the temperature to the set temperature value set using a predetermined ratio, and calculating from the relation table based on the measured descent time value. Therefore, even if the fluid in the second circulation path is indirectly heated by the heat medium, the circulation flow rate value can be obtained accurately. In addition, since the measurement of the descent time value until the temperature of the fluid in the second circulation path drops to the set temperature value is the main time necessary for the detection process, the value of the circulation flow rate can be obtained quickly. As described above, it is possible to quickly and accurately detect the circulating flow value of the fluid that is subjected to indirect heating only by measuring the descent time value without using the detection means that directly measures the circulating flow rate such as a flow rate sensor. become able to.

  According to the hot water device of claim 2, the first circulation path is constituted by a hot water circulation path for realizing a heating function by circulatingly supplying hot water as a heating medium between the heating terminal and the second circulation path. As a path, it is constituted by a recirculation circuit in which hot water in the bathtub is circulated as a fluid between the heat exchanger and the bathtub, and as the heat exchanger, hot water is circulated and supplied as a heat source so that the hot water in the bathtub is liquid- By constructing with a reheating heat exchanger that heats by liquid heat exchange, the structure of the hot water device is, for example, a hot water heating function with a hot water heating function that is configured in a two-can three-water channel system. Therefore, the application target of the present invention can be further clarified. And, even in a recirculation circuit where direct flow rate detection means such as a flow sensor cannot be installed due to contamination of hair, etc., so that the recirculation flow rate for retreat can be grasped accurately and quickly Become.

  Further, according to the hot water device of claim 3, as the circulating flow rate detection processing unit, the circulating flow value detection processing is executed in a state in which the remaining hot water is detected in the bathtub in the hot water filling control for the bathtub. This makes it possible not only to detect the value of the circulating flow rate using the remaining hot water, but also to obtain the value of the circulating flow rate at this stage, so that subsequent hot water filling control can be simplified. become. For example, since the value of the circulation flow rate is grasped by the detection process by the circulation flow rate detection processing unit, the amount of remaining hot water can be easily calculated using the value of the circulation flow rate, and as a result, the hot water filling control is completed. The required time can be significantly reduced compared to the conventional case.

It is a mimetic diagram showing a bath can with a 2 can 3 water channel type water heater as a hot water device to which an embodiment of the present invention is applied. It is a block diagram of a control configuration related to hot water filling control and hot water circulation flow rate detection processing of the hot water device. It is a flowchart which mainly shows the procedure of a circulating flow rate detection process. FIG. 6 is a relationship diagram of temperature and time showing a change characteristic of a going-out temperature after stopping supply of the heat medium circulation from the heating circuit to the reheating heat exchanger when the circulation flow rate is large and when the circulation flow rate is small. Heat medium circulation supply from the heating circuit to the reheating heat exchanger while continuing the recirculation circulation for the recirculation flow of hot and cold water in various circulation flow rates and combinations at various temperature conditions Is a relationship diagram based on experimental data showing the relationship between the change in the going temperature and the elapsed time after the operation is stopped, and the change in the going temperature over time is expressed by a predetermined ratio λ. is there. FIG. 6 is a relationship diagram showing the relationship between the circulation flow rate and the descent time in the case of λ = 0.5 from the relationship diagram of FIG. 5. FIG. 4 is a relationship diagram that is a premise of the technique proposed in Patent Document 1 and shows a change in temperature and time indicating a change characteristic of the forward temperature after combustion heating is stopped by a combustion burner when the circulating flow rate is large and when the circulating flow rate is small. It is a relationship diagram.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a hot water apparatus according to an embodiment of the present invention. This hot water apparatus is constructed in a composite type having both a hot water supply function, a hot water circulation type hot water heating function, a flow replenishment function, and a pouring function. It is composed of. In other words, a reheating circuit provided with a hot water supply circuit 2, a recirculation circuit 3, a pouring circuit 4, and a hot water heating recirculation circuit 5 and configured as a recirculation circuit 3 as a liquid-liquid heat exchange type. The hot water in the bathtub B is reheated and heated by the heat exchanger 31 and is supplied to the heating terminal 61 from the heating circuit 5 as a heat source for reheating the reheating heat exchanger 31 ( The heat medium is circulated and supplied. 1 exemplifies a latent heat recovery type that achieves high efficiency by recovering latent heat from combustion exhaust gas in addition to sensible heat in the combustion heating unit. Even a non-high-efficiency type to which a recovery function is added can be implemented and the effects of the present invention can be obtained. In the following description, the heating circulation circuit 5 is shown as an example having a specific configuration such as one that circulates and supplies low-temperature water and high-temperature water to a plurality of types of low-temperature and high-temperature heating terminals. Heating a fluid (for example, bathtub hot water) circulated through a circulation path (for example, a recirculation circuit) is performed by using a heat medium (for example, high-temperature water) circulated and supplied from the other circulation path (for example, a heating circulation circuit) as a heat source. As long as it is performed by liquid heat exchange type indirect heating, a configuration other than these may be provided, and is not limited in the application of the present invention.

  The hot water supply circuit 2 includes a hot water supply heat source device 21, a water inlet 22 through which water supply such as tap water is introduced into the hot water supply heat source device 21, and a hot water discharged from the hot water heat-exchanged and heated by the hot water supply heat source device 21. Road 23 is provided. The hot water supply heat source unit 21 includes a primary heat exchanger 25 that mainly heats by sensible heat accompanying combustion of the combustion burner 24, and a secondary heat exchanger 26 that recovers latent heat from the combustion exhaust gas and preheats it. It preheats through the secondary heat exchanger 26 and then passes through the primary heat exchanger 25. A mixed water bypass passage 27 branched from the incoming water passage 22 is joined in the middle of the outgoing water passage 23, and from the incoming water passage 22 by adjusting the opening of the mixed water valve 27a with respect to the outgoing hot water from the primary heat exchanger 25. A predetermined amount of water is mixed to adjust the temperature to the set hot water supply temperature, and then hot water is supplied to the hot water tap 28 and the like. The water inlet 22 is provided with an incoming water flow sensor 22a for detecting the incoming water flow rate and an incoming water temperature sensor 22b for detecting the incoming water temperature. The hot water tap 28 is provided in the outlet hot water 23 at a position downstream of the junction of the bypass 27. A flow rate adjustment valve 23a for adjusting the hot water supply flow rate and a hot water temperature sensor 23b for detecting the hot water temperature are provided. Then, the upstream end of the pouring path 41 of the pouring circuit 4 is branched from the pouring path 23, and the downstream end is connected to the return flow path 32 a of the recirculation circuit 3 at the junction M. However, the hot water can be poured into the bathtub B through the pouring channel 41 and the return channel 32a.

  The recirculation circuit 3 includes a recirculation heat exchanger 31 of a liquid-liquid heat exchange type and is interposed in a recirculation circuit 32. The recirculation circuit 32 constituting the second circulation path is the recirculation circuit 32. The return channel 32a and the forward channel 32b are configured. Then, the hot water of the bathtub (fluid circulated in the circulation path) taken out from the bathtub B through the bath return channel 32a by the operation of the circulation pump 33 for reheating flows into the reheating heat exchanger 31, and this The reheating heat exchanger 31 is reheated by liquid-liquid heat exchange with a heat source, and the hot water after reheating is sent to the bathtub B through the forward flow path 32b. In addition to the circulation pump 33, the return flow path 32a includes a pressure-type water level detection sensor 30 that detects the water level in the bathtub B, a water flow switch 34 that opens a flap when the circulation flow passes, and outputs an ON command for circulation determination. And a return temperature sensor 35 for detecting the temperature of hot water from the bathtub B (equivalent to the hot water temperature in the bathtub B; return temperature), and a downstream position of the reheating heat exchanger 31 in the forward flow path 32b. A forward temperature sensor 36 is provided for detecting the temperature (forward temperature) of the hot and cold water after reheating. A heat source circulation path 37 for circulating and supplying a heat source is connected to the reheating heat exchanger 31, and the reflow heat valve 38 for reheating interposed in the heat source circulation path 37 is opened and closed, The heat source is switched to ON / OFF switching by switching the circulation of the heat source or stopping the circulation of the heat source. The heat source circulation path 37 and the flow heat valve 38 constitute a part of a hot water circulation path 55 of the heating circulation circuit 5 described later.

  The pouring circuit 4 includes the pouring passage 41 and the pouring valve 42 interposed in the pouring passage 41. In addition to the pouring valve 42, a pouring amount sensor 43 that detects the pouring flow rate, a pair of check valves 44, and the like are interposed in the pouring passage 41. The pouring valve 42 is controlled to be opened and closed by the controller 7, and by pouring, the hot water in the tapping channel 23 is poured into the bathtub B through the pouring channel 41 and the recirculation circuit 32 (return channel 32a), and a predetermined amount. The hot water filling is performed.

  The heating heat source unit 51 of the heating circulation circuit 5 is preheated by recovering latent heat from the combustion exhaust gas, and a primary heat exchanger 53 that mainly heats by sensible heat accompanying the combustion of the combustion burner 52, similarly to the hot water source heat source unit 21. The secondary heat exchanger 54 is provided. The heating circulation circuit 5 includes a warming water circulation path 55 for heating function that constitutes the first circulation path, and a heating circulation pump 56, and has two kinds of temperatures of low-temperature water and high-temperature water as a heat medium. Hot water is circulated and supplied as a heat source to multiple types of heating terminals for low and high temperatures.

  That is, the hot water circulation path 55 sends the low temperature water returned to the expansion tank 57 and stored to the primary heat exchanger 53 by the operation of the heating circulation pump 56, where it is heated by the combustion burner 52. Water is supplied as a heat source to the reheating heat exchanger 31 through the heat source circulation path 37, or is supplied to a high-temperature heating terminal 61 such as a bathroom dryer through the high-temperature water supply path 59 and the high-temperature forward header 60. It has become so. Also, by the operation of the circulation pump 56, the low-temperature water in the expansion tank 57 is supplied to the low-temperature heating terminal 63 such as a floor heater via the low-temperature forward header 62, and the low-temperature water is radiated from all the heating terminals 61 and 63 by heat radiation. The low-temperature water thus obtained is circulated through the return header 64 and the low-temperature water supply passage 65 through the secondary heat exchanger 54 for recovering latent heat, preheated and then returned to the expansion tank 57. Yes. The above operation control is executed by heating operation control of the heating control unit 73 described later, for example, by turning on a heating switch of a heating remote controller.

  In addition, although illustration is abbreviate | omitted, in the secondary heat exchangers 26 and 54, the drain water produced | generated when the combustion exhaust gas was cooled and condensed by heat exchange for latent heat recovery is derived, and the derived drain water is neutralized A drain water treatment circuit is also provided for drainage after treatment. Further, the combustion burners 24 and 52 are operated to receive a fuel gas supplied from a fuel supply system having an original gas valve or a gas proportional valve and a combustion air supplied from a blower fan. In the example shown in the figure, the combustion capacity can be switched in a plurality of stages by opening / closing switching control of a plurality of capacity switching valves.

  In the hot water apparatus, the controller 7 controls various operation controls such as hot water supply operation, pouring operation by pouring / water injection, reheating operation, and heating operation to the output from the remote controller 8 and the output from the various sensors. In addition to the above, the circulating flow rate of the recirculation circuit 3 is detected by a control process without using a direct detection means such as a flow rate sensor as will be described later. The controller 7 includes a hot water supply control unit that performs a hot water supply operation for the hot water tap 28 by the hot water supply circuit 2, and a reheating control unit that performs a reheating operation that raises the hot water in the bathtub B to a predetermined temperature by the recirculation circuit 3. A hot water filling control unit 71 (see FIG. 2) for performing hot water filling operation by pouring and pouring water into the bathtub B through the hot water pouring channel 41, and a circulating flow rate detection processing unit 72 constituting a control means for detecting the circulating flow rate, It has. The controller 7 is mainly configured by a microcomputer including a CPU and a rewritable memory, and performs the above-described various operation controls based on programs and various data stored in the memory.

  The outline of the hot water supply operation control by the hot water supply control unit will be described. Due to the hot water supply request (for example, opening operation of the hot water tap 28 by the user), the incoming water flow rate into the incoming water channel 22 becomes the minimum operating flow rate (MOQ; eg 3 liters / minute) If the incoming water flow rate sensor 22a detects that the combustion burner 24 is operated, the combustion burner 24 is controlled at a predetermined combustion amount so that the temperature of the hot water discharged into the hot water outlet 23 becomes a predetermined temperature. 24 is made to burn. Then, the temperature of the hot water supplied to the hot-water tap 28 and the like is controlled by mixing and adjusting the temperature of the hot water discharged from the hot water outlet 23 and the water branched into the hot water outlet 23 through the bypass 27. The operation is controlled so as to reach the set hot water supply temperature (set pouring temperature).

  When the automatic flow switch of the remote control 8 is turned on, the pouring operation control by the flow control unit and the reheating operation control after pouring are executed by automatic processing, or the pouring switch of the remote control 8 is turned on. Then, the pouring operation control is executed. In the pouring operation control, if the thermal valve 38 has been closed before that, the hot valve 38 is opened. If the thermal valve 38 is open, the thermal valve 38 is closed and then the hot valve 42 is opened. To start. If the inlet water flow pressure sensor 22a detects that the water supply pressure from the outside of the machine is received by this opening operation and water enters the water inlet 22 and the water flow into the water inlet 22 exceeds the minimum operating flow rate (MOQ). After the combustion burner 24 is combusted and hot water having a set pouring temperature is supplied from the hot water supply passage 23 to the pouring passage 41, it is supplied to the junction M of the return flow passage 32a. Then, a predetermined amount of hot water is poured into the bathtub B through the return flow path 32a from the junction M, and the bathtub B is filled.

  The chasing control by the chasing control unit is performed as follows. That is, when the user turns on the reheating switch of the remote control 8 or when the user turns on the automatic bath switch in the previous stage and the filling of the water up to the predetermined water level in the bathtub B is completed by the filling of the hot water, the reheating is finished. A command is output, and the circulation pump 33 is operated in response to the refill command. When the water flow switch 34 is turned on by the start of the operation, the combustion operation control of the heating heat source unit 51 is started and the combustion burner 52 is operated. This combustion operation is performed so that the return temperature detected by the return temperature sensor 35 maintains the set bath temperature. That is, if the return temperature detected by the return temperature sensor 35 is lower than the bath set temperature, the combustion operation is performed, and if it is equal to or higher than the bath set temperature, the combustion operation is stopped.

  The hot water filling control unit 71 first determines whether or not there is remaining hot water in the bathtub B (represented as “remaining hot water” including the remaining water) by circulation determination, and if it is determined that there is no remaining hot water, for example, In a predetermined stage, the pouring circuit 4 pours water up to a predetermined water level, and if it is determined that there is remaining hot water, the remaining hot water is used to perform a circulating flow rate detection process, and then the remaining hot water amount is calculated. On the basis of the above, the hot water is poured by the pouring circuit 4 to fill the hot water to the predetermined water level. In the circulation determination, as shown in FIG. 3, the recirculation circulation pump 33 is operated (step S1), it is determined whether or not the water flow switch 34 is turned on (step S2), and the water flow switch 3 is not turned on. While determining that there is no remaining hot water (or less than a predetermined amount) and pouring (NO in step S2), if the water flow switch 3 is turned on, it is determined that there is remaining hot water (YES in step S2). Note that the pouring is performed by opening and converting the pouring valve 42 and dropping hot water of a predetermined temperature into the bathtub B through the pouring channel 41 and the recirculation circuit 32 by the combustion operation of the combustion burner 24 for hot water supply.

  If it is determined that there is remaining hot water (YES in step S2), the circulating flow rate of the recirculation circuit 3 is detected by the circulating flow rate detection processing unit 72 using the remaining hot water. FIG. 2 shows a control configuration for only hot water filling and circulating flow rate detection processing, and FIG. 3 is a flowchart for hot water control centering on circulating flow rate detection processing. In Step S1, it is desirable that the operation of the circulation pump 33 is continued for a certain period of time to stir the remaining hot water in the bathtub B so as to have a uniform temperature.

  As the circulation flow rate detection process, first, a reheating process is performed (step S3).

  That is, while the operation of the recirculation circulation pump 33 is maintained as it is, the primary heat for heating is maintained by switching the opening of the thermal valve 38, the operation of the circulation pump 56 for heating, and the combustion start of the combustion burner 52 for heating. The high-temperature water heated by the exchanger 53 is circulated and supplied to the reheating heat exchanger 31 as a heat source. Thereby, the hot water in the bathtub B sent to the reheating heat exchanger 31 through the return flow path 32a of the recirculation circulation path 32 is subjected to liquid-liquid heat exchange with the high-temperature water in the reheating heat exchanger 31. Heated and heated hot water is sent to the bathtub B through the outward flow path 32b. That is, the hot water in the bathtub B is replenished. In addition, when the heating operation by the heating circuit 5 is performed at this time, only the open switching of the thermal valve 38 is performed as the reheating process in step S3. During this reheating, the return temperature detected by the return temperature sensor 35 and the forward temperature detected by the forward temperature sensor 36 are recorded. Here, the reason why both the return temperature and the return temperature are detected and recorded during the reheating period is to be used in the subsequent calculation of the remaining hot water amount (step 9).

  When the hot / cold water temperature in the bathtub B obtained by the detected return temperature rises to a predetermined target temperature (YES in step S4), the process proceeds to a process for detecting the circulation flow rate (step S5).

  That is, at least the operation of the heating circulation pump 56 is stopped, while the operation of the recirculation circulation pump 33 is continued. At this time, the combustion of the heating combustion burner 52 may be stopped along with the operation stop of the heating circulation pump 56. In addition, in order to cut off the heat source supply (supply of high-temperature water) to the reheating heat exchanger 31, the operation of the heating circulation pump 56 is not stopped, but the operation of the circulation pump 56 for heating is stopped. This is to ensure responsiveness. That is, since the thermal valve 38 requires a certain time for switching the opening and closing thereof, the heat source supply to the reheating heat exchanger 31 is immediately performed by stopping the operation of the heating circulation pump 56 instead of switching the thermal valve 38 closed. I try to block it. In addition, at the same time as the operation of the heating circulation pump 56 is stopped (the heat source supply to the reheating heat exchanger 31 is interrupted), the return temperature (Tl (0 ); Elapsed time t = 0 is shown in parentheses) and forward temperature (Th (0); Elapsed time t = 0 is shown in parentheses), and timer means 721 is started. At the same time, the set temperature value T (g) for measuring the descent time value Δτg is set based on the return temperature Tl (0) and the forward temperature Th (0) at the time when the heat source supply is cut off (t = 0). .

The set temperature value T (g) is set as follows. That is, the return temperature Tl (0) is multiplied by a predetermined ratio λ (0 <λ <1.0) to the difference between the return temperature Tl (0) and the return temperature Tl (0) minus the return temperature Tl (0). A value obtained by adding the obtained value is set as a set temperature value T (g). This can be expressed by an arithmetic expression as follows.
T (g) = Tl (0) + λ · [Th (0) −Tl (0)] (1)
When equation (1) is transformed with respect to λ, equation (2) is obtained.
λ = [T (g) −Tl (0)] / [Th (0) −Tl (0)] (2)
The ratio λ can be determined from the viewpoint of more accurately detecting the circulation flow rate based on the descent time value described later. For example, the ratio λ is ½ (λ = 0.5) or 2 / 3 (λ = 0.67) can be adopted. In the present embodiment, 0.5 corresponding to a so-called half-life is employed as the value of the ratio λ (0 <λ <1.0).

  The setting of the ratio λ will be described in more detail. FIG. 4 shows the relationship between the change in the forward temperature Th (t) and the elapsed time t when the heat source supply to the reheating heat exchanger 31 is shut off while the recirculation operation of the reheating circulation path 32 is continued. Is shown as a characteristic diagram. Even if the heat source supply is interrupted, the reheating heat exchanger 31 is filled with the high-temperature water supplied so far, so the going-out temperature Th (t) is immediately determined from the time when the heat source supply is stopped (t = 0). Without descending, after maintaining Th (0) for a certain time, it begins to descend slowly. At that time, the larger the circulating flow rate, the earlier the temperature drop starts and the more rapid the drop, and the smaller the circulating flow rate, the later the temperature drop starts and the degree of the drop becomes milder. Then, the going-out temperature Th (t) continues to fall and eventually converges to the return temperature Tl (0) at the time when the heat source supply is stopped. Here, the drop time value required to drop to the temperature value corresponding to the set temperature difference when λ = 0.5 is set is Δτ2 when the circulating flow rate is large, and Δτ1 when the circulating flow rate is small. It will be. Here, if the value of λ is increased, the difference in the fall time value between the case where the circulating flow rate is large and the case where the flow rate is small is reduced, and if the value of λ is reduced, the above drop time value is reduced. The difference becomes large. That is, if the value of λ is set too large, the accuracy of the circulating flow rate value obtained from the measured descent time value may be impaired, while conversely, the value of λ is set too small. In such a case, the measurement of the descent time value may require a considerable amount of elapsed time, which may result in lack of quickness.

Furthermore, it demonstrates in detail, referring FIG. In FIG. 5, the change in the detected forward temperature from the time when the heat source supply is cut off is measured for a circulation flow of various combinations of return temperature and forward temperature flowing in the recirculation circuit 32 at various circulation flow rates, The relationship between the value obtained by converting the measurement result into the ratio λ and the elapsed time is obtained by experiment. As the circulation flow, the circulation flow rate is set to 4 L / min, 6 L / min, 8 L / min, 10 L / min, and the hot water temperature (return temperature) in the bathtub B is 33 ° C., 40 ° C., 48 ° C. Three types of hot water and water were prepared, and the hot water and water at various temperatures were circulated at the above four types of circulating flow rates. Then, the change in the forward temperature Th (t) measured at every elapsed time t is converted into the ratio λ based on the following formula (3) corresponding to the formula (2), and the ratio λ and the elapsed time are calculated. FIG. 5 shows the relationship. In the experiment, the actual circulation flow value was confirmed using an electromagnetic flow meter.
λ = [T (t) −Tl (0)] / [Th (0) −Tl (0)] (3)

  According to FIG. 5, even if the return temperatures are 33 ° C., 40 ° C., 48 ° C., and so on, the relationship between the ratio λ and the elapsed time depends only on the difference in the four types of circulating flow values. It can be seen that it is uniquely determined. In this regard, FIG. 6 shows the relationship between the circulation flow rate and the elapsed time for three types of circulation flows in which the hot water temperature in the bathtub B is 33 ° C., 40 ° C., and 48 ° C., using the test data of FIG. According to FIG. 6, the relationship between the circulation flow rate and the elapsed time is the same so that the circulation flow can be regarded as almost the same regardless of the circulation flow under any temperature condition (three types of 33 ° C., 40 ° C., and 48 ° C.). I know that there is. In short, the relationship between the circulating flow rate and the descent time value is represented by a substantially constant relationship curve even when there are differences in hot water temperature of 33 ° C., 40 ° C., and 48 ° C., that is, the degree of heating by the reheating heat exchanger 31. It can be seen that the relationship between the descent time value required to drop to a certain temperature value and the circulation flow rate shows a substantially constant relationship. For this reason, if a relationship table (relation curve or numerical table) between the descent time value and the circulation flow rate is obtained in advance by testing, and this relationship table is stored in the table storage unit 722 of the circulation flow rate detection processing unit 72, By measuring a timer value corresponding to the descent time value (see step S7 in FIG. 3), the value of the circulation flow rate can be determined from the relation table and detected.

  Returning to FIG. 5, each elapsed time at λ = 0.9 (elapsed time at each intersection of the line L1 and the change curve) is close to each other at λ = 0.3 in the four types of circulation flow rates. The elapsed time (elapsed time at each intersection of the line L4 and the change curve) is greatly different from each other, and each elapsed time value is also prolonged. On the other hand, each elapsed time at λ = 0.5 or λ = 0.67 (the elapsed time at each intersection of the lines L3, L2 and the change curve) has an appropriate interval and all are within 5 seconds. It can be seen that the range is extremely short, that is, the value of the circulating flow rate can be detected in a very short time.

  From the above, there is a correlation between the time required for the forward temperature to drop from the heat source supply cutoff time to a predetermined temperature value (fall time value) and the circulation flow rate, and the circulation at the time of heat source supply cutoff. Regardless of the temperature condition of the flow (temperature of hot water in the bathtub B), the value of the circulation flow rate is uniquely obtained only by detecting the descent time value. For this reason, if a relationship table between the descent time value and the circulation flow rate is determined in advance by experiments, the value of the circulation flow rate can be easily and quickly determined simply by measuring the descent time value. It becomes like this. Thereby, even if the circulating flow of the hot water in the bathtub is indirectly heated by the liquid-liquid heat exchange type reheating heat exchanger 31, the value of the circulating flow rate can be detected.

  Returning to the flowchart of FIG. 3, the change in the forward temperature T (t) by the forward temperature sensor 36 from the time when the heat source supply is cut off is monitored (step S6). If the detected forward temperature T (t) drops to the set temperature value T (g) (YES in step S6), the timer value (fall time value) of the timer means 721 at that time is output (step S7). ). That is, the time required for the forward temperature detected after passing through the reheating heat exchanger 31 to drop from the forward temperature T (0) detected at the time of heat source supply cutoff to the set temperature value T (g). Get the value (fall time value). Based on the output descent time value, the corresponding circulation flow rate value is determined from the relational table stored in advance in the table storage unit 722, and this calculated circulation flow rate value is set as the circulation flow rate value in the recirculation circuit 32. (Step S8). Here, the relationship table is a table in which the relationship between the descent time value and the circulation flow rate value is determined in advance by experiments and stored in the table storage unit 722.

As such a relational table, a plurality of kinds of relational tables can be set depending on the level of the circulating flow temperature (temperature of hot water in the bathtub B; return temperature) when the heat source supply is cut off. That is, for each of a plurality of different temperatures as the temperature of the circulation flow, a relationship table applied to the circulation flow at that temperature can be set, and the plurality of types of relationship tables can be stored in the table storage unit 722. Then, during the circulation flow rate detection process, a relation table corresponding to the return temperature is called based on the return temperature detected by the return temperature sensor 35, and the value of the circulation flow rate is calculated from the relation table. In addition, you may make it use the boiling preset temperature of the bathtub B set to the remote control 8 instead of return temperature as temperature of a circulating flow. In short, the influence of the heat mass may be ignored and the circulation flow rate value detection process may be performed. However, more accurate circulation is performed by taking into account the influence of the heat mass (heat capacity) of the reheating heat exchanger 31. In order to perform the flow rate value detection process, the heat mass can be easily grasped from the temperature of the circulating flow at the time when the heat source supply is cut off, and can be corrected based on the temperature of the circulating flow at the time of cutting off the heat source supply.

  The table storage unit 722 stores a plurality of types of relationship tables that are set in advance to be applied to a plurality of different outside temperatures, and an outside temperature sensor (for example, an F point thermistor; not shown) provided in the hot water apparatus. The relationship table to be applied can be changed and set depending on whether the outside air temperature detected by (1) is high or low. Further, such correction based on the outside air temperature can be added to the relational table applied to the circulating flow at each temperature of the plurality of different circulating flows.

  The storage setting for the table storage unit 722 may be stored before shipment from the factory, or may be stored in the table storage unit 722 after the hot water apparatus is installed at the site of use. Further, after use, the relationship table may be updated and stored in a new one.

  Thus, the circulating flow value detection process is completed, and the circulating flow value can be detected (acquired) without using a detection unit that directly measures the circulating flow, such as a flow sensor. In addition, the circulation flow rate detection process can be completed very quickly, such as only a few seconds after the circulation flow rate detection process is started. Moreover, since the start time of the timer value is the time when the circulation pump 56 for heating is stopped for the detected descent time value, the start time can be accurately grasped, and the detected forward temperature is set at the end of the timer value. Since this is the time when the temperature value T (g) is detected, the end of the temperature value can be accurately grasped. As a result, as the descent time value to be collated with the relational table, a very accurate value can be measured without a control time lag, and the corresponding circulating flow value is derived based on the accurate descent time value. Therefore, an accurate circulating flow rate value can be obtained.

  If the detection of the circulating flow rate value is completed in step S8, the remaining hot water amount is calculated by the hot water filling control unit 71 using this circulating flow rate value (step 9). The remaining hot water amount is calculated by calculating the amount of heat using the detected return temperature, detected forward temperature, and the circulating flow rate value recorded during the reheating period (step S3). That is, the integrated heat quantity given by the reheating is obtained by multiplying the temperature rise width obtained by subtracting the detected return temperature from the detected forward temperature by the circulating flow value and integrating according to the elapsed time. And what is necessary is just to calculate the amount of remaining hot water from this integrated calorie | heat amount and the temperature rise of the return temperature (bath hot water temperature) in the same elapsed time.

  If the amount of remaining hot water can be ascertained in the calculation of step S9, the amount of hot water (or amount of water) to be added up to the set water level of the hot water filling for bathtub B can be ascertained. The hot water filling control unit 71 ends the hot water filling (step S10).

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. That is, in the above embodiment, when it is determined in step S2 that there is remaining hot water (YES in step S2), the circulating flow rate detection processing unit 72 detects the circulating flow rate of the recirculation circuit 3 using the remaining hot water. In order to perform the reheating control, the heat source supply to the reheating heat exchanger 31 is stopped and the temperature drop time is measured, but the present invention is not limited to this. When normal reheating control is executed, the circulation flow rate is measured so that the temperature drop time is measured from the end time of the reheating control (when the heat source supply to the reheating heat exchanger 31 is stopped). It is also possible to shift to detection processing.

  In the embodiment, the descent time value required to drop to one type of set temperature value obtained by multiplying by the ratio λ is detected, and the circulation flow value corresponding to this one type of descent time value is calculated from the relation table. However, the present invention is not limited to this, and based on two set temperature values obtained using two types of λ1 (for example, λ1 = 0.5) and λ2 (for example, λ = 0.67), these two types Detecting two types of fall time values when the going temperature has dropped to the set temperature value, and calculating two circulation flow values corresponding to these two types of fall time values from the relationship table, averaging them, and finally A circulation flow rate value can be obtained. By performing the averaging process, it becomes possible to detect the circulating flow rate value with higher accuracy.

  Instead of storing and setting in advance in the table storage unit 722 a plurality of types of relationship tables corresponding to how the outside air temperature is high or low as the relationship table used in the embodiment, or for the measured fall time value or its fall time value The circulation flow rate value calculated from the relationship table may be corrected according to whether the outside air temperature is high or low. For example, if the outside air temperature detected by the outside air temperature sensor is lower than the reference temperature range, it is considered that the degree of the temperature drop is large and the time required for the temperature drop is short, so the timer value output from the timer means 721 is on the plus side. On the contrary, if the outside air temperature is higher than the reference temperature range, a negative correction is added to the timer value. The correction width may be, for example, plus / minus 0.05 seconds. By adding such correction based on the outside air temperature, it becomes possible to obtain an even higher precision (accuracy) as the circulation flow rate value obtained by the detection process.

  As the relationship table, a relationship curve or a linear relationship line obtained by linearly approximating the relationship curve may be set, a mathematical expression defining such a relationship curve may be set, or a numerical table may be set You may do either. To set the mathematical formula, an approximate expression can be determined from the experimental results using, for example, the least square method, etc., and the relationship curve can be specified in the coordinate system of the descent time value and the circulating flow value based on this approximate expression. Alternatively, the approximate expression itself can be set as a relation table. In addition, when the numerical table is set as a relational table, if there is no exact matching circulating flow value, the circulating flow value may be calculated by linear interpolation between adjacent circulating flow values. it can.

31 Heat exchanger for reheating 32 Reheating circuit (second circuit)
35 Return temperature sensor (return temperature detection means)
36 Outward temperature sensor (outward temperature detection means)
52 Combustion burner for heating (heating source)
55 Hot water circuit (first circuit)
72 Circulating flow rate detection processing unit 721 Timer unit 722 Table storage unit B Bathtub

Claims (3)

A first circulation path in which a heat medium heated by a heating source is circulated as a heat source, a second circulation path in which a fluid is circulated, and heat exchange heating of the fluid in the second circulation path A heat exchanger, wherein the heat exchanger is connected to the first circulation path so that the heat medium can be circulated as a heat source, and the fluid is indirectly heated by the heat medium. In
Return temperature detecting means for detecting the temperature of the return-side fluid in the second circulation path at a position upstream of the heat exchanger in the circulation direction; and the second temperature at a position downstream of the heat exchanger in the circulation direction. A forward temperature detection means for detecting the temperature of the forward fluid in the circulation path, and a circulation flow rate detection processing unit for detecting the circulation flow rate of the fluid circulated in the second circulation path by control processing;
The circulating flow rate detection processing unit includes timer means for measuring an elapsed time value, and a table storage unit for storing a predetermined relationship table,
The relationship table includes the circulation flow rate of the fluid in the second circulation path and the forward fluid detected by the forward temperature detection means from the time when the circulation supply of the heat medium to the heat exchanger is interrupted. It is set in advance with respect to the relationship with the descent time value required for the temperature to fall to the set temperature value,
The circulation flow rate detection processing unit shuts off the circulation supply of the heat medium to the heat exchanger while maintaining the second circulation path in a state where the fluid is circulating, and the forward temperature detection means The detected temperature change of the forward fluid is monitored, and the timer means measures the fall time value required for the temperature of the forward fluid to drop from the point of circulation supply of the heat medium to the set temperature value. And configured to determine and detect a corresponding circulating flow rate value from the relationship table based on the measured descent time value; and
As the set temperature value, the return temperature obtained by subtracting the return temperature from the return temperature detected by the return temperature detection means with respect to the return temperature detected by the return temperature detection means at the time when the circulating supply of the heating medium is interrupted. A value obtained by multiplying the return temperature difference by a predetermined ratio is set.
A hot water device characterized by that. The hot water device according to claim 1,
The first circulation path is constituted by a hot water circulation path for realizing a heating function by circulatingly supplying hot water as a heat medium between the heating terminals,
The second circulation path is constituted by a reheating circulation path in which hot water in the bathtub is circulated as a fluid between the heat exchanger and the bathtub,
The said heat exchanger is a hot water apparatus comprised with the reheating heat exchanger which circulates and supplies the said hot water as a heat source, and heats the hot water in the said bathtub by liquid-liquid heat exchange. The hot water device according to claim 2,
The circulating flow rate detection processing unit is a hot water device configured to execute a detection process of a circulating flow rate value in a state in which the remaining hot water is present in the bathtub in the hot water filling control for the bathtub.

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