JP6540378B2 - Combined heat source machine - Google Patents

Description

  The present invention relates to, for example, a complex heat source apparatus in which bath water circulated in a supplementary circulation path is indirectly heated by liquid-liquid heat exchange, using a heat medium circulated and supplied in a circulation path for hot water heating as a heat source. The present invention relates to a control technique capable of detecting a circulation flow rate of bathtub water circulated in the follow-up circulation path by processing on control without using a detection means such as a flow rate sensor directly detecting the flow rate.

  In order to detect the circulation flow rate of the fluid without using a flow rate sensor, the applicant of the present application proposed a technique that can be detected by a control process in Patent Document 1 below. This is because the hot water in the bath, which is circulated in the reheating circulation path, is heated directly by the combustion burner while passing through the heat exchanger in the can, the reheating is performed in a one-can, two-channel water heater equipped bath pot. The circulation flow rate of the hot water circulated in the circulation path can be detected. Specifically, the hot and cold water in the bath is circulated between the reheating heat exchanger heated by the combustion burner, and the hot and cold water heated by the reheating heat in the reheating heat exchanger is supplied to the bath After performing circulation heating of making it happen, processing is started for detection of 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 interruption. Then, after the heating stop, the fall time value required for the temperature of the hot and cold water supplied to the bath through the additional heat exchanger to drop by the predetermined set temperature difference is detected, and from the predetermined relationship table The circulation flow value corresponding to the descent time value is determined. Such a relation table is a table in which the relation between the descent time and the circulation flow rate is previously obtained by a test or the like and set in advance as a table or a relation.

Patent No. 5326650 gazette

  By the way, the compound heat source machine constituted by the compound type provided with the warm water circulation type heating function in addition to a hot water supply function and a reheating function is known. In such a complex heat source machine, the heat exchanger for hot water supply and the heat exchanger for heating are heated by the combustion burner, and the heat medium heated by the heat exchanger for heating is used as a heat source for the external heating terminal At the same time as circulating supply, it is configured as a two-can three-channel system so as to supply circulating as a heat source to a liquid-liquid heat exchange type reheating heat exchanger for reheating. That is, the reheating heat exchanger is not directly heated by the combustion burner, but indirectly heated by using the heating circulating heat medium which is heated by the combustion burner and circulated and supplied. ing.

  The technique proposed in Patent Document 1 for detecting a circulating flow rate of circulating hot water in a bath passing through a reheating heat exchanger for a complex heat source machine configured in such a two-can three-channel system However, there is a disadvantage that the circulation flow can not be detected quickly and accurately. The reason is that in the case of direct reheating by the combustion burner, the reheating is immediately stopped if the combustion operation of the combustion burner is stopped, and the circulating water passing through the reheating heat exchanger is The temperature will drop sharply, for example as shown in FIG. The technique proposed in the above-mentioned Patent Document 1 utilizes the rapid temperature drop which suddenly changes from temperature rise to descent, and the fall time value (for example, Δτ1 or the time required to fall by a predetermined temperature difference ΔT). By detecting Δτ 2), the value of circulation flow rate can be obtained quickly and accurately. However, since the reheating heat exchanger in the case of the two-can three-channel system described above is indirect heating by liquid-liquid heat exchange using a heat medium circulated and supplied as a heating heat source as a heat source, the heating heat source Even if the combustion burner for heating the heat source is turned off, the already heated heat medium is circulated and supplied to the reheating heat exchanger through the piping, so the heat supply to the reheating heat exchanger is not stopped. Also, the heat input supplied is also unknown because it depends on the circulation flow rate on the heating side. Furthermore, even if it is possible to shut off the circulating supply of the heat medium to the reheating heat exchanger, the reheating heat exchanger is filled with the heat medium which is the heat source for a while after the interruption time. The heat transfer from the heat medium to the circulating hot water will be continued. For this reason, the conversion point itself from temperature rise to fall such as the one-can two-channel system does not clearly appear, nor does it cause a rapid temperature drop, and the technique proposed in Patent Document 1 is applied as it is. However, it is not possible to obtain a rapid and accurate detection of the circulation flow rate.

  In addition, in the reheating circulation path for reheating and heating the hot and cold water in the above-mentioned bathtub, for example, an apparatus capable of directly detecting the circulation flow rate such as a normal water flow type flow rate sensor is not installed. The reason for trying to grasp and detect is not just a cost situation but because there are the following circumstances. That is, since the fluid circulated in the reheating circulation path is bath water, and hair and the like are expected to be mixed in the bath water, a flow rate sensor should be installed for fear of clogging due to such hair and the like. It is impossible in practice to directly detect the circulation flow rate. Also, even if the rated discharge flow rate of the circulation pump installed in the circulation circuit is known, the circulation flow rate in the circulation circuit connecting the bathtub with the open water surface and the heat exchanger is the same as that of the circulation pump. It does not match the discharge flow rate, and the circulation flow rate can not be grasped by the discharge flow rate of the circulation pump. Furthermore, as the significance of grasping the circulation flow rate of the reheating circulation path, it takes time to grasp the amount of the remaining hot water, particularly when there is residual hot water in the bath, and as a result, automatic hot water filling is completed There is a problem that the time will be long, and in order to solve this problem as well, there is a circumstance that the rapid and accurate detection (acquisition) of the circulation flow rate of the circulation circuit is particularly important.

  Also, since the operation control for the refueling operation and the operation control for the heating operation are executed based on separate requirements and logics, they are used as heat sources for reheating for the reheating heat exchanger. The temperature of the heat medium of the heating heat source to be circulated and supplied may change suddenly due to the unique change control on the heating side. In this case, in the reheating heat exchanger, it is conceivable that the bathing water on the reheating side which is subjected to liquid-liquid heat exchange by the heat medium on the heating side is also destabilized due to the sudden change. Furthermore, when the combustion unit for heating the heating medium on the heating side is influenced by another control system to cause an unintended fluctuation, it is also conceivable to further increase the destabilization.

  The present invention has been made in view of such circumstances, and an object thereof is to detect a circulation flow rate in a circulation path, a flow rate sensor, etc., even if heating to the circulation fluid is by indirect heating. An object of the present invention is to provide a combined heat source machine which can be carried out without using the above-mentioned direct detection means and which can accurately and reliably detect the circulation flow rate.

  In order to achieve the above object, according to the first aspect of the present invention, a heating burner for hot water combustion and heating, and a heat medium circulatingly supplied to a heating circuit as a heat source for heating hot water are heated. And the circulating supply of the heat medium heated by the heating combustion burner as a heat source, and the circulating supply of hot and cold water from the bath through the reheating circulating passage to receive the hot and cold water through liquid-liquid heat exchange Heat-exhaust heat exchanger for reheating and heating, and a circulation flow rate detection process for detecting the circulation flow rate of hot and cold water circulated in the reheating circulation path through the reheating heat exchanger through control processing And the combustion burner for hot water supply and the combustion burner for heating are configured to receive combustion supply via a common fuel adjustment valve, and the circulation flow rate detection processing unit In a state where the circulation of the heat source to the reheating heat exchanger through the heating circuit is shut off while maintaining the state that water is circulating, it passes through the reheating heat exchanger and goes to the bathtub The following technical measures have been taken for a complex heat source machine configured to detect the circulation flow rate based on the drop condition of the forward temperature of the hot water.

  That is, as the circulation flow rate detection processing unit, at least one control condition of the hot water supply combustion burner and the heating combustion burner is monitored, and the heat exchange for reheating is started when the detection process of the circulation flow rate is started. When control is performed to bring about rapid fluctuations in the temperature of the heat medium circulated and supplied to the unit, the process for detecting the circulation flow rate is performed after waiting for a time set in advance as required for the forward temperature to stabilize. The configuration is to start (claim 1).

  In the case of the first aspect of the invention, at the start of the process of detection of the circulation flow rate, at least one of the hot water supply combustion burner and the heating combustion burner is circulated and supplied to the reheating heat exchanger. When control that causes rapid fluctuations in the temperature of the heating medium is executed, the process of detecting the circulation flow rate is started after waiting for the set time, so even if the temperature of the heating medium fluctuates rapidly Even if the forward temperature in the circulation path is destabilized, it can be stabilized while waiting for the set time, and the detection processing of the circulation flow rate started after that can be performed accurately and reliably It becomes possible.

  In the combined heat source apparatus according to the first aspect of the present invention, as the circulating flow rate detection processing unit, the combustion start of the hot water supply combustion burner, switching of the combustion capacity, or the like when the hot water supply combustion burner is simultaneously burned with the heating combustion burner. When control including any one of combustion stop is executed, it may be configured to wait for a set time before the start of the detection processing of the circulation flow rate, assuming that control to bring about rapid fluctuation of the heat medium temperature is executed. (Claim 2). If the combustion burner for hot water supply is simultaneously fired and the control of combustion start, combustion capacity switching or combustion stop is executed on the hot water side, the control on the combustion adjustment valve is also changed along with the execution of the hot water side control. As a result, the combustion state of the heating combustion burner also fluctuates. For this reason, the temperature of the heat medium circulated and supplied to the reheating heat exchanger is rapidly changed, and the temperature of the hot water passing through the reheating heat exchanger is also destabilized. Therefore, if such control is executed, the action of claim 1 can be obtained more specifically and surely by waiting for the start of the detection process of the circulation flow rate for the set time.

  Further, in the combined heat source apparatus according to the first aspect of the present invention, as the circulation flow rate detection processing unit, control is performed to switch the combustion capacity of the heating combustion burner while the heat medium is circulatingly supplied to the reheating heat exchanger. At the same time, it may be configured to wait for a set time before the start of the detection processing of the circulation flow rate, assuming that the control for causing rapid fluctuation in the heat medium temperature is executed (claim 3). Also in this case, when control to switch the combustion capacity of the heating combustion burner is executed, the temperature of the heat medium heated by the heating combustion burner is also rapidly changed, and the reheating heat exchanger is The temperature of the passing hot and cold water will also be destabilized. Therefore, if such control is executed, the action of claim 1 or claim 2 can be obtained more specifically and reliably by waiting for the start of the detection process of the circulation flow rate for the set time.

  In the second invention, a heating combustion burner for heating a heat medium to be circulated and supplied to a heating circuit as a heat source for heating hot water, and a circulation supply of a heat medium heated by the heating combustion burner as a heat source On the other hand, a reheating heat exchanger for reheating and heating the hot and cold water by liquid-liquid heat exchange upon receiving a circulating supply of hot and cold water from the bath through the reheating circulation path, and the heat exchange through the reheating heat exchanger. And a circulation flow rate detection processing unit for detecting the circulation flow rate of hot water circulated in the reheating circulation path according to control processing, wherein the circulation flow rate detection processing portion circulates the hot water in the reheating circulation path Of the hot water passing through the reheating heat exchanger toward the bathtub while blocking the circulation supply of the heat source to the reheating heat exchanger through the heating circuit while maintaining the It provides the following technical means directed to a composite heat source machine that is configured to detect the circulating flow rate based on the drop status of the temperature. That is, as the circulation flow rate detection processing unit, the control state of the heating combustion burner is monitored, and when the detection process of the circulation flow rate is started, the temperature of the heat medium circulated and supplied to the reheating heat exchanger When control causing sudden change is executed, the process for detecting the circulation flow rate is started after waiting for a time set in advance as the time required for the coming temperature to stabilize. .

  In the case of the second aspect of the invention, at the start of the process of detecting the circulating flow rate, control that brings about rapid fluctuations in the temperature of the heat medium circulatingly supplied to the reheating heat exchanger, under control of the heating combustion burner. Since the process of detecting the circulation flow rate is started after waiting for the set time when the command is executed, even if the temperature of the heat medium fluctuates rapidly, the temperature inside the circulation circuit is destabilized. Even if this is done, it becomes possible to stabilize while waiting for the set time, and it becomes possible to accurately and reliably perform the detection process of the circulation flow rate started thereafter. That is, unlike the case of the first aspect of the invention, in a complex heat source machine which is not provided with a hot water supply circuit and is constituted by a heating circuit and a reheating circuit in which a heat medium as a heating heat source is circulated and supplied as a reheating heat source. The second aspect of the present invention also enables accurate and reliable detection of the circulation flow rate.

  And also in the complex heat source machine of the second invention, as the circulating flow rate detection processing unit, control is executed to switch the combustion capacity of the heating combustion burner while the heat medium is being circulated and supplied to the reheating heat exchanger. When it is determined that the control for causing rapid fluctuation of the heat medium temperature is executed, the control unit can be configured to stand by for a set time before the start of the detection processing of the circulation flow rate (claim 5). By doing this, when control is performed to switch the combustion capacity of the heating combustion burner, the temperature of the heat medium heated by the heating combustion burner is also rapidly changed, and the heat for reheating The passing temperature of the hot and cold water passing through the exchanger also becomes unstable. Therefore, if such control is executed, the action of claim 4 can be obtained more specifically and surely by making the start of the detection processing of the circulation flow amount wait for the set time.

  As described above, according to the combined heat source apparatus of the first invention, at the start of the detection processing of the circulation flow rate, at least one of the control conditions of the hot water supply combustion burner and the heating combustion burner. When the control that brings about rapid fluctuations in the temperature of the heat medium circulated and supplied to the reheating heat exchanger is executed, the process for detecting the circulation flow rate is started after waiting for the set time. Even if the temperature of the heat medium fluctuates rapidly and the temperature inside the circulation circuit becomes unstable, it can be stabilized while waiting for the set time, and detection of the circulation flow started thereafter Processing can be performed accurately and reliably.

  In particular, according to the combined heat source machine of claim 2, as the circulating flow rate detection processing unit, the combustion start and the switching of the combustion capability of the hot water supply combustion burner when the hot water supply combustion burner is simultaneously burned with the heating combustion burner. Alternatively, when control including any one of combustion stop is executed, it is assumed that the control for causing rapid fluctuation of the heat medium temperature is executed, and the control is made to wait for the set time before the start of the detection processing of the circulation flow rate. Thus, the following effects can be obtained. That is, when the combustion burner for hot water supply is simultaneously burned and the control to start the combustion, switch the combustion ability or stop the combustion is executed on the hot water side, the control on the combustion adjustment valve is also changed along with the execution of the hot water side control. As a result, the combustion state of the heating combustion burner also fluctuates. For this reason, the temperature of the heat medium circulated and supplied to the reheating heat exchanger is rapidly changed, and the temperature of the hot water passing through the reheating heat exchanger is also destabilized. Therefore, if such control is executed as in claim 2, the effect of claim 1 can be obtained more specifically and reliably by making the start of the detection processing of circulation flow rate wait for a set time. It will be.

  Further, according to the combined heat source machine of the invention of claim 3, as the circulating flow rate detection processing unit, control is performed to switch the combustion capacity of the heating combustion burner while the heat medium is circulatingly supplied to the reheating heat exchanger. The following effects can be obtained by waiting for the set time before the start of the detection processing of the circulation flow rate, assuming that the control that brings about a sudden change in the heat medium temperature is executed when it is executed. That is, when control to switch the combustion capacity of the heating combustion burner is executed, the temperature of the heat medium heated by the heating combustion burner is also rapidly changed, and passes through the reheating heat exchanger The hot water temperature will also be destabilized. Therefore, if such control is executed as in claim 3, the effect of the invention of claim 1 can be obtained more specifically and surely by making the start of the detection processing of circulation flow rate wait for a set time. Will be able to

  According to the combined heat source machine of the second aspect of the present invention, at the start of the detection process of the circulation flow rate, the temperature of the heat medium circulated and supplied to the reheating heat exchanger in the control situation of the heating combustion burner When the control that causes fluctuation is executed, the process of detecting the circulation flow rate is started after waiting for the set time, so even if the heat medium temperature fluctuates rapidly, the forward temperature in the additional circulation path Even if it is destabilized, it can be stabilized while waiting for the set time, and it becomes possible to accurately and reliably perform the detection process of the circulation flow which is started thereafter. That is, unlike the case of the first aspect of the invention, in a complex heat source machine which is not provided with a hot water supply circuit and is constituted by a heating circuit and a reheating circuit in which a heat medium as a heating heat source is circulated and supplied as a reheating heat source. The second aspect of the present invention also enables accurate and reliable detection of the circulation flow rate.

  Then, according to the combined heat source machine of claim 5, as the circulation flow rate detection processing unit, control is performed to switch the combustion capacity of the heating combustion burner while the heat medium is being circulated and supplied to the reheating heat exchanger. When the control for causing rapid fluctuation of the heat medium temperature is executed when the heat medium temperature is set, the following effect can be obtained by waiting for the set time before the start of the detection process of the circulation flow rate. That is, when control to switch the combustion capacity of the heating combustion burner is executed, the temperature of the heat medium heated by the heating combustion burner is also rapidly changed, and passes through the reheating heat exchanger The hot water temperature will also be destabilized. Therefore, if such control is executed as in claim 5, the effect of the invention of claim 4 can be obtained more specifically and surely by making the start of the detection processing of circulation flow rate wait for a set time. Will be able to

It is a schematic diagram which shows the bath can with 2 cans 3 channel type water heater as a compound heat source machine to which embodiment of this invention is applied. It is a block diagram of control composition concerning the pouring control of this compound heat source machine, and the circulation flow rate detection processing of hot water. This is the first half of the flowchart mainly showing the procedure of the circulation flow rate detection process. This is the second half of the flowchart that mainly shows the procedure of the circulation flow rate detection process. It is a related figure of the temperature and time which shows the change characteristic of the going temperature after stopping the heat carrier circulation supply to the heat exchanger for a reheating from a heating circulation path in the case where circulation flow volume is large and small. A heat medium circulation supply from the heating circuit to the reheating heat exchanger while continuing the reheating circulation for the reheating circulation flow of hot water and water at various circulation flow rates and combinations of various temperature conditions. The relationship between the change in temperature and the change in time after stopping cessation is measured, and the change with time of the change in temperature is represented by a predetermined ratio λ, and the relationship diagram based on experimental data showing the relationship between the ratio λ and elapsed time is there. FIG. 6 is a relationship diagram showing the relationship between the circulation flow rate and the falling time for the case of λ = 0.5 from the relationship diagram of FIG. 5. It is a related figure which becomes a premise of the art proposed by patent documents 1, and the case where temperature and time which show the change characteristic of the going temperature after the combustion heating stop by a combustion burner in the case where circulation flow rate is large and small is shown. FIG.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

  FIG. 1 is a schematic view of a combined heat source apparatus according to an embodiment of the present invention. This combined heat source unit is configured as a combined type having both functions of hot water supply function, hot water circulation type hot water heating function, bath reheating function, and pouring function, and it is particularly structurally two cans and three water channels It is constructed in a formula. That is, it comprises a hot water supply circuit 2, a reheating circulation circuit 3, a pouring water supply circuit 4, and a heating water circulation circuit 5 as a reheating circulation circuit 3, which is configured as a liquid-liquid heat exchange system. The hot water in the bathtub B is reheated and heated by the heat exchanger 31 for high temperature water to be supplied from the heating circuit 5 to the heating terminal 61 as a heat source for reheating with respect to the heat exchanger 31 for reheating ( The heat medium) is circulated and supplied. In addition, although the compound heat source machine illustrated in FIG. 1 is an example of a latent heat recovery type that achieves high efficiency by performing latent heat recovery from combustion exhaust gas in addition to sensible heat in the combustion heating unit, the present invention The present invention can be implemented even if it is not a highly efficient type to which a latent heat recovery function is added, and the operation and effect of the present invention can be obtained. Also, in the following description, an example is shown in which the heating circulation circuit 5 has a specific configuration such as one that cyclically supplies low temperature water or high temperature water to multiple types of heating terminals for low temperature and high temperature. The heating of the fluid (eg, bath water) circulated in the circulation path (eg, the recurrent circulation circuit) is performed using the heat medium (eg, high temperature water) circulated and supplied from the other circulation path (eg, the heating circuit) as a heat source As long as it is performed by indirect heating of liquid heat exchange type, it may have a configuration other than these, and is not limited for the application of the present invention.

  The hot water supply circuit 2 includes a hot water supply heat source machine 21, a water intake channel 22 for supplying water such as tap water to the hot water supply heat source machine 21, and a hot water discharge for hot water subjected to heat exchange heating by the hot water supply heat source machine 21. And a road 23. The hot water supply heat source machine 21 is provided with a primary heat exchanger 25 which is mainly heated by sensible heat accompanying the combustion of the combustion burner 24 and a secondary heat exchanger 26 which recovers latent heat from combustion exhaust gas and preheats it. After preheating through the next heat exchanger 26, it is passed through the primary heat exchanger 25. In the middle of the outlet passage 23, a bypass passage 27 for mixed water branched from the inlet passage 22 is joined, and the outlet water from the primary heat exchanger 25 is adjusted from the inlet passage 22 by adjusting the opening degree of the mixture valve 27a. A predetermined amount of water is mixed, and the temperature is adjusted to the set hot water supply temperature, and then the hot water supply valve 28 or the like is supplied with hot water. A water inlet flow rate sensor 22a for detecting the water inlet flow rate and an water inlet temperature sensor 22b for detecting the water inlet temperature are provided in the water inlet channel 22, and the hot water outlet 28 is located downstream of the junction point of the bypass passage 27 A flow rate adjustment valve 23a for adjusting the hot water supply flow rate to the hot water and a hot water temperature sensor 23b for detecting the hot water temperature are provided. Then, the upstream end of the pouring passage 41 of the pouring circuit 4 is branched from the tapping passage 23, the downstream end is connected to the return flow passage 32 a of the reheating circulation circuit 3 at the junction M, and the hot water of the tapping passage 23 Is capable of pouring into the bathtub B through the pouring path 41 and the return flow path 32a.

  In the reheating circulation circuit 3, a liquid-liquid heat exchange type reheating heat exchanger 31 is interposed in the reheating circulation path 32. The additional circulation path 32 is constituted by the return flow path 32a and the forward flow path 32b. Then, by the operation of the circulation pump 33 for reheating, the hot and cold water in the tub B taken out from the bathtub B through the return flow channel 32a flows into the reheating heat exchanger 31 and the inside of the heat exchanger 31 for reheating. The water is reheated and heated by liquid-liquid heat exchange with a heat source described later, and the hot and cold water after reheating and heating is circulated so as to be sent to the bathtub B through the forward flow path 32b. In addition to the circulation pump 33, a pressure type water level detection sensor 30 for detecting the water level in the bathtub B in the return flow path 32a, and a water flow switch 34 for opening the flap by passing the circulation flow and outputting an ON command for circulation judgment. , And a return temperature sensor 35 for detecting the temperature of hot and cold water from the bathtub B (equal to the temperature of hot and cold water in the bathtub B; return temperature), and the downstream flow passage 32b is provided with the downstream position of the heat exchanger 31 for reheating A going temperature sensor 36 is provided to detect the temperature (going temperature) of hot and cold water after reheating and heating. A heat source circulation path 37 for circulating and supplying a heat source is connected to the reheating heat exchanger 31, and the heat source circulation path is supplied by opening and closing the heating valve 38 in the heat source circulation path 37. Switching to stop the circulation supply, or the like, and ON / OFF switching of reheating heating is performed. The heat source circulation path 37 and the heating valve 38 constitute a part of the 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 flow rate sensor 43 for detecting a pouring flow rate, a pair of check valves 44, and the like are interposed in the pouring path 41. The pouring valve 42 is controlled to open and close by the controller 7, and by the execution of pouring, the hot water of the pouring passage 23 is poured into the bathtub B through the pouring passage 41 and the reheating circulation passage 32 (return passage 32a). It is supposed to be filled with water.

  The heating heat source machine 51 of the heating circuit 5, as with the hot water supply heat source machine 21, recovers latent heat from the combustion exhaust gas by primary heat exchanger 53 which is mainly heated by sensible heat accompanying combustion of combustion burner 52 and preheating it. And a secondary heat exchanger 54. And heating circulation circuit 5 is provided with warm water circulation passage 55 which constitutes a heating circulation passage, and circulation pump 56 for heating, and warm water of two kinds of temperature of low temperature water and high temperature water as a heat medium of a heating heat source It circulates as a heat source with respect to several types of heating terminals 61 and 63 for low temperature and high temperature.

  That is, the hot water circulation passage 55 sends the low temperature water returned to the expansion tank 57 and stored therein to the primary heat exchanger 53 by the operation of the heating circulation pump 56, and the high temperature after heating by the combustion burner 52 here. Water is supplied as a heat source to the reheating heat exchanger 31 through the heat source circulation path 37, or is supplied to the high temperature heating terminal 61 such as a bathroom dryer through the high temperature water supply passage 59 and the high temperature forward header 60. It has become so. Further, 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 by the operation of the circulation pump 56, and the low temperature is dissipated from all the heating terminals 61 and 63. Low temperature water is returned through the return header 64 and the low temperature water supply passage 65 to the secondary heat exchanger 54 for latent heat recovery, preheated, and then returned to the expansion tank 57 to be circulated. There is. The above-described operation control is executed by the heating operation control of the heating control unit 72 described later, for example, by the ON operation of the heating switch of the heating remote control.

  Although illustration is omitted, in the secondary heat exchangers 26, 54, the drain water generated by the combustion exhaust gas being 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 to drain water after treatment.

  Here, the two types of combustion burners 24 and 52 are for supplying the fuel gas from the fuel supply system having the source gas valve 66 and the gas proportional valve 67 as the fuel adjustment valve interposed therebetween, and for combustion from the blower fan 68. It operates in response to the supply of air and combustion. The controller 7 changes and controls the opening of the gas proportional valve 67 so that the gas pressure of the fuel gas to both of the two combustion burners 24 and 52 can be changed and adjusted. That is, the two combustion burners 24 and 52 are both burned by the fuel gas controlled by the gas proportional valve 67. Further, the combustion capability of each of the combustion burners 24 and 52 in the illustrated example can be switched in a plurality of stages by the on-off switching control by the controller 7 of the plurality of capability switching valves 241 to 243, 521, 522.

  That is, the combustion burner 24 for hot water supply is comprised from many (for example, ten) combustion tubes, and supply of fuel gas is divided every predetermined number. For example, the supply switching of the fuel gas to the two combustion pipes is performed by opening and closing switching of the capacity switching valve 241, and the supply switching of the fuel gas to the three combustion pipes is performed by opening and closing switching of the capacity switching valve 242, The supply switching of the fuel gas to the five combustion pipes is performed by the opening / closing switching of the capacity switching valve 243. Similarly, the combustion burner 52 for heating is also composed of, for example, four combustion pipes, and switching of the fuel gas supply to the two combustion pipes is performed by switching on and off of the capacity switching valve 521. By switching, the supply switching of fuel gas to the other two combustion tubes is performed. And, in the combustion burner 24 for hot water supply, the combustion capability can be switched in five steps by opening and closing control of the capability switching valves 241 to 243 alone or in combination, and in the combustion burner 52 for heating, the capability switching valve The combustion capability can be switched in two stages by the open / close control of 521, 522. As an example of capacity switching, two combustion pipes are burned when only capacity switching valve 241 is switched to open (one stage), and three combustion pipes are burned when only capacity switching valve 242 is switched to open (two stages) When the capacity switching valve 243 is switched open, the five combustion pipes are burned (three stages), and when the capacity switching valves 241 and 243 are both opened, the seven combustion pipes are burned (four stages), the capacity switched When the valves 241 to 243 are opened together, 10 combustion pipes are burned (5 stages). Further, in the combustion burner 52 for heating, two combustion pipes are burned (one stage) when only the capacity switching valve 521 is switched open, and four combustion pipes are burned when both capacity switching valves 521, 522 are switched open. Operated (two stages). In addition, in the combustion burner 24 for hot water supply, in each combustion stage of 1 to 5 stages, the opening degree of the gas proportional valve is changed to exhibit a predetermined range of combustion ability from small capacity to large capacity, and for heating The combustion burner 52 also exhibits a predetermined range of combustion capability in each of the one or two combustion stages. As a result, at a certain lower combustion stage, the adjustment of the gas proportional valve 67 increases the capacity from the small capacity to the large capacity, and then switches to the upper combustion stage and simultaneously changes the gas proportional valve 67 to the small capacity, As the gas proportional valve is increased to the large capacity side in the combustion stage, the combustion capacity can be increased from the minimum to the maximum by switching the combustion stage and adjusting the change of the gas proportional valve.

  The controller 7 controls the operation of various heat sources such as hot water supply operation, pouring operation, pouring operation, refueling operation and heating operation with the controller 7 from the remote controller 8 and from the various sensors. As described later, detection of the circulation flow rate of the recurrent circulation circuit 3 is performed by control processing without using a direct detection means such as a flow rate sensor. The controller 7 circulates a heat medium (high temperature water / low temperature water) to the heating terminals 61 and 63 by the heating circulation circuit 5 and the hot water supply control unit 71 (refer to FIG. The heating control unit 72 that performs heating operation by supplying, the pouring control unit 73 that performs pouring and pouring operation to the bathtub B through the pouring passage 41 and the pouring control unit 73 that performs pouring operation; Is provided with a refueling control unit 74 for performing a refueling operation for raising the temperature to a predetermined temperature, and various control units including a circulation flow rate detection processing unit 75 constituting control means for detecting a circulation flow rate. The controller 7 is mainly configured by a microcomputer including a CPU and a rewritable memory, and performs various operation control and the like based on programs and various data stored in the memory.

  An outline of the hot water supply operation control by the hot water supply control unit 71 will be described. The flow rate of water entering the water inlet 22 is at least the minimum working flow rate (MOQ; for example 3 liters / minute) due to the hot water supply request If it is detected by the incoming water flow rate sensor 22a, the combustion system such as the combustion burner 24 is operated and controlled to burn with a predetermined amount of combustion so that the temperature of the hot water discharged to the hot water discharge passage 23 becomes a predetermined temperature. The burner 24 is to be burned. Then, the temperature of the hot water supplied to the hot water supply plug 28 or the like is controlled by the remote control 8 by mixing the temperature of the hot water let out to the hot water outlet 23 and the water made branched into the outlet 23 via the bypass 27 and adjusting the temperature. Operation control is performed so that the set hot water supply temperature (set pouring temperature) is set. In order to realize the hot water supply of this set hot water supply temperature, the opening / closing switching control of the capacity switching valves 241 to 243 and the opening degree control of the gas proportional valve 67 are performed so that the combustion burner 24 exerts the combustion capacity of a predetermined required number. To be executed.

  In addition, when the bath automatic switch of the remote control 8 is turned ON, pouring control by the pouring control unit 73 and pouring control by the pouring operation control unit 74 after pouring are executed by automatic processing, or the remote control 8 When the pouring switch is turned ON, the pouring operation control will be executed. The pouring control is performed as it is if the thermal valve 38 is closed before that, or if the thermal valve 38 is open, the thermal valve 38 is closed and then the pouring valve 42 is opened. It is started by. If the water supply pressure from the outside of the machine is received by this opening operation and water is input to the water inlet 22, and the water flow into the water inlet 22 becomes equal to or more than the minimum operation flow (MOQ) After the combustion burner 24 is burned and the hot water of the set pouring temperature is supplied from the tapping path 23 to the pouring path 41, it is supplied to the junction M of the return flow path 32a. Then, a predetermined amount is poured from the junction point M to the bathtub B through the return flow path 32a, and the bathtub B is filled.

  The reheating control by the reheating control unit 74 is performed as follows. That is, if the user turns on the reheating switch of the remote control 8 or if the user turns on the bath automatic switch in the previous step and pouring of water within the bathtub B is finished by pouring control, the reheating A command is output, and in response to this repelling command, the circulation pump 33 is operated. When the water flow switch 34 is turned on by the operation start, the combustion operation control of the heating heat source unit 51 is started, and the combustion burner 52 is burned. The combustion operation is performed so that the return temperature detected by the return temperature sensor 35 maintains the set temperature. That is, the combustion operation is performed if the detection return temperature of the return temperature sensor 35 is lower than the set temperature, and the combustion operation is stopped if the temperature is higher than the set temperature.

  The pouring control unit 71 first determines whether or not there is remaining hot water (denoted as "remaining hot water" including the remaining water) in the bathtub B by circulation determination, and if it is determined that there is no remaining hot water, for example The water injection circuit 4 separates into predetermined stages and pours water up to a predetermined water level, and if it is determined that there is remaining hot water, circulation water flow detection processing is performed using the remaining hot water, and the amount of remaining hot water is calculated. In order to pour the water up to the above-mentioned predetermined water level, the short circuit is poured by the pouring circuit 4 based on the above. In the circulation determination, as shown in FIG. 3, the circulation pump 33 for reheating is operated (step S1), it is determined whether the water flow switch 34 is turned on (step S2), and the water flow switch 3 is not turned on. While it is judged that there is no remaining hot water (or less than a predetermined amount) and pouring is carried out (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). It is to be noted that the pouring is performed by opening the pouring valve 42 so that hot water of a predetermined temperature is dropped into the bathtub B through the pouring passage 41 and the reheating circulation passage 32 by the combustion operation of the combustion burner 24 for hot water supply.

  If it is determined that there is residual water (YES in step S2), in principle, the residual flow is used to detect the circulation flow rate of the recurrent circulation circuit 3 by the circulation flow rate detection processing unit 75. The circulation flow rate detection processing unit 75 includes a timer means 751, a table storage unit 752, and a heat source fluctuation monitoring unit 753, and as described later, the heat source fluctuation monitoring unit 753 of the heat source (high temperature water circulated and supplied from the heating circuit 5). It monitors whether or not sudden fluctuations occur in the situation, and detects the circulation flow rate in a stable state by excluding the influence on the detected temperature accompanying the sudden fluctuation on the heat source side. Such monitoring by the heat source fluctuation monitoring unit 753 is performed for the control situation of the combustion burners 24 and 52 and the gas proportional valve 67 as described later by the hot water supply control unit 71 and the heating control unit 72 of the controller 7. There is. In addition, FIG. 3 is a flowchart which concerns on the pouring control centering on circulation flow rate detection processing. Further, in step S1, it is desirable that the operation of the circulation pump 33 be continued for a certain period of time to stir the remaining hot water in the bath B and keep the temperature at a uniform temperature.

  In order to detect the circulation flow rate, the reheating process is performed first (step S3). That is, the operation of the circulation pump 33 for reheating is maintained as it is, while the open switching of the thermal valve 38, the operation of the circulation pump 56 for heating, and the start of combustion of the combustion burner 52 for heating The high temperature water heated by the exchanger 53 is used as a heat source to be circulated and supplied to the reheating heat exchanger 31. Thereby, the hot and cold water of the bathtub B sent to the reheating heat exchanger 31 through the return flow path 32a of the reheating circulation path 32 is subjected to liquid-liquid heat exchange with the high-temperature water in the reheating heat exchanger 31. The water is heated and the heated water is sent to the bath B through the forward flow path 32b. That is, the hot and cold water in the bathtub B is repelled. At this time, when the heating operation by the heating circuit 5 is being performed, since the high temperature water is circulating, only the open switching of the thermal valve 38 is performed as the reheating processing in step S3. Then, during the 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 that both the return temperature and the forward temperature are detected and recorded during the refueling period is to be used in the later calculation of the amount of remaining hot water (step 10).

  When the temperature of the hot and cold water in the bathtub B obtained by the detected return temperature rises to a predetermined target temperature (YES in step S4), in principle, the detection processing of the circulation flow rate is performed. However, based on the output condition from the heat source fluctuation monitoring unit 753, which monitors whether or not the heat source suddenly fluctuates in parallel with the refueling control before moving to the detection processing of the circulation flow rate. It is checked whether there is a rapid temperature fluctuation in the high temperature water as a heat source circulated and supplied to the heat exchanger 31 for boiling, that is, whether or not there is a sudden change on the heat source side immediately before (step S5) After confirming that there is no sudden change on the heat source side (NO in step S5), the process proceeds to a process (step S6) for detecting the circulation flow rate.

  That is, if there is no sudden change on the heat source side (NO in step S5), at least the operation of the heating circulation pump 56 is stopped, and the operation of the reheating circulation pump 33 is continued (step S6). 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. Further, in order to shut off the heat source supply (the supply of high temperature water) to the reheating heat exchanger 31, the operation of the heating circulation pump 56 is stopped instead of the closing switching of the thermal valve 38. , To ensure quick response. That is, since the thermal valve 38 requires a certain time for switching its opening and closing, the heat source supply to the reheating heat exchanger 31 is immediately made by stopping the operation of the heating circulation pump 56 instead of closing the thermal valve 38. I am trying to shut off. In addition, at the same time as the operation of the heating circulation pump 56 is shut down (shutoff of the heat source supply to the reheating heat exchanger 31), the return temperature (Tl (0 ; The parentheses indicate the elapsed time t = 0), and the forward temperature (Th (0); the parentheses indicate the elapsed time t = 0), and start the timer means 751 (step S6). . At the same time, the set temperature value T (g) for measuring the fall time value Δτg is set based on the return temperature Tl (0) and the forward temperature Th (0) at the heat source supply cutoff time (t = 0). (Step S6).

The setting of the set temperature value T (g) is performed as follows. That is, the return temperature Tl (0) is obtained by subtracting the return temperature Tl (0) from the forward temperature Th (0) and multiplying the forward / return temperature difference by a predetermined ratio λ (0 <λ <1.0). A value obtained by adding the obtained value is set as a set temperature value T (g). This is expressed by the following equation.
T (g) = Tl (0) + λ · [Th (0) −Tl (0)] (1)
If equation (1) is modified 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 fall time value described later. For example, the forward / return temperature difference is 1⁄2 (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 adopted as the value of the ratio λ (0 <λ <1.0).

  The setting of the ratio λ will be described in more detail. In FIG. 5, while the heat source supply to the reheating heat exchanger 31 is shut off, the relationship between the change of the going temperature Th (t) and the elapsed time t when the circulation operation of the reheating circulation path 32 is continued. Is shown as a characteristic diagram. Even if the heat source supply is shut off, the reheating heat exchanger 31 is filled with the high-temperature water supplied so far, so the forward temperature Th (t) is immediately after the heat source supply stop point (t = 0) After falling for a certain period of time after maintaining Th (0), it begins to fall gently. At that time, the larger the circulation flow rate, the earlier the temperature drop starts and the steeper the fall degree, and the smaller the circulation flow rate the temperature drop starts later and the fall degree becomes gentler. Then, the forward temperature Th (t) continues to drop and eventually converges to the return temperature Tl (0) at the heat source supply stop point. Here, the fall time value required to fall to the temperature value corresponding to the set temperature difference when λ = 0.5 is set to Δτ2 when the circulation flow rate is large, and Δτ1 when the circulation flow rate is small. It will be. Here, if the value of λ is increased, the difference between descent time values when the circulation flow rate is large and when it is small decreases, and if the value of λ is decreased, the descent time value of The difference is large. That is, if the value of λ is set too large, there is a possibility that the accuracy of the value of the circulation flow rate obtained from the measured fall time value may be lost, and conversely, the value of λ is set too small. In addition, it may take a considerable amount of elapsed time to measure the fall time value, which may cause a lack of promptness.

Further, this will be described in detail with reference to FIG. In FIG. 6, for the circulation flow of various combinations of return temperature and return temperature flowing to the reheating circulation path 32 at various circulation flow rates, the change in the detection temperature from the heat source supply cutoff point is measured. The relationship between the value obtained by converting the measurement result into the ratio λ and the elapsed time is obtained by experiment. The circulation flow rate is set to 4 L / min, 6 L / min, 8 L / min, 10 L / min as the circulation flow rate, and the temperature (return temperature) of the hot water in the bathtub B is 33 ° C., 40 ° C., 48 ° C. Three types of hot and cold water were prepared, respectively, and the various types of hot and cold water were circulated at the four types of circulation flow rates. Then, the change of the forward temperature Th (t) measured for each elapsed time t is converted into a ratio λ based on the following equation (3) corresponding to the above equation (2), and the ratio λ and the elapsed time The relationship is shown in FIG. In addition, about the actual circulation flow rate value in the case of experiment, it confirmed using the electromagnetic flowmeter.
λ = [T (t) −Tl (0)] / [Th (0) −Tl (0)] (3)
According to FIG. 6, first of all, even if return temperatures are different from each other such as 33 ° C., 40 ° C., and 48 ° C., the relationship between the ratio λ and the elapsed time depends only on the difference between the four types of circulation flow rates. It turns out that it is decided uniquely. In this regard, FIG. 7 shows the relationship between the circulation flow rate and the elapsed time for the three types of circulation flows of 33 ° C., 40 ° C., and 48 ° C. in the bath B using the test data of FIG. According to FIG. 7, the relationship between the circulation flow rate and the elapsed time is the same to the extent that they can be regarded as almost the same, regardless of the temperature conditions (three types of 33 ° C., 40 ° C., 48 ° C.). I know that there is. In short, even if there is a difference between the water temperature 33 ° C., 40 ° C. and 48 ° C., that is, there is a difference in the heating degree by the reheating heat exchanger 31, the relationship between the circulation flow rate and the fall time value is represented by a nearly constant relationship curve. It can be seen that the relationship between the descent time value required to drop to a certain temperature value and the circulation flow shows an almost constant relationship. Therefore, if a relationship table (relationship curve or numerical value table) between the descent time value and the circulation flow rate is obtained in advance by a test, and this relationship table is stored in the table storage unit 752 of the circulation flow rate detection processing unit 75, By measuring the timer value (see step S8 in FIG. 4) corresponding to the descent time value, it is possible to detect and detect the value of the circulation flow rate from the relation table.

  Returning to FIG. 6, while the elapsed times at λ = 0.9 (the elapsed times at the intersections of the line L1 and the change curve) are close in four types of circulation flow rates, each at λ = 0.3. The elapsed time (the elapsed time at each intersection of the line L4 and the change curve) is largely separated from each other, and each elapsed time value is also prolonged. On the other hand, each elapsed time at λ = 0.5 and λ = 0.67 (the elapsed time at each intersection of the lines L3 and L2 and the change curve) has an appropriate interval and all are within 5 seconds. It can be seen that the value of the circulation flow rate can be detected in a very short time range, that is, 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 point to the predetermined temperature value (fall time value) and the circulation flow rate, and the circulation at the heat source source cutoff point Regardless of the temperature condition of the flow (the temperature of the water in the bathtub B), the value of the circulation flow rate can be uniquely obtained only by detecting the falling time value. Therefore, if the relationship table between the descent time value and the circulation flow rate is determined in advance by experiment, it is possible to easily and quickly determine the value of the circulation flow rate simply by measuring the above-mentioned descent time value. It will be. Thereby, even if the circulating flow of hot and cold water in the bath is subjected to indirect heating in 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. 4, the change of the temperature T (t) by the temperature sensor 36 from the heat source supply cutoff point is monitored (step S7). When the detected temperature T (t) falls to the set temperature T (g) (YES in step S7), the timer value (falling time value) of the timer means 751 at that time is output (step S8). ). That is, the time required for the temperature to be detected after passing through the reheating heat exchanger 31 to fall from the temperature T (0) detected at the heat source supply cutoff time 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 relationship table stored in advance in the table storage unit 752, and the determined circulation flow rate value is set as the circulation flow rate value in the recurrent circulation path 32. (Step S9). Here, the relation table is a table in which the relation between the descent time value and the circulation flow rate value is determined in advance by experiment or the like, and stored and set in the table storage unit 752.

As such a relationship table, it is possible to set a plurality of different relationship tables depending on the level of the temperature (temperature of hot and cold water in the bathtub B; return temperature) of the circulating flow at the heat source supply cutoff time. That is, for each of a plurality of mutually different temperatures as the temperature of the circulating flow, relation tables to be applied to the circulating flow of that temperature can be set, and these plurality of types of relation tables can be stored in the table storage unit 752. Then, in the process of detecting the circulation flow rate, 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 determined from the relation table. In addition, you may make it use the boiling setting temperature of the bathtub B set to the remote control 8 instead of return temperature as temperature of a circulating flow. In short, detection processing of the circulation flow rate value may be performed neglecting the influence of the heat mass, but furthermore, the circulation with higher accuracy taking into consideration the influence of the heat mass (heat capacity) of the reheating heat exchanger 31. In order to detect the flow rate value, the heat mass can be easily grasped by the temperature of the circulating flow at the heat source supply cut-off time, and the heat mass can be corrected based on the temperature of the circulating flow at the heat source supply cut-off time.

  In addition, the table storage unit 752 stores a plurality of types of relationship tables set in advance as application to a plurality of different outside air temperatures, and an outside air temperature sensor (for example, an F point thermistor; It is possible to change and set the relation table to be applied depending on the level of the outside air temperature detected by (omitted). In addition, such correction based on the outside air temperature may be added to the relationship table applied to the circulation flow of the temperature for each of the temperatures of the plurality of circulation circulations different from each other.

  The storage setting for the table storage unit 752 may be stored before shipment from the factory, or may be stored in the table storage unit 752 after the complex heat source unit is installed at the use site. Also, after use, the relationship table may be updated and stored in a new one.

  As described above, the process of detecting the circulation flow rate ends, and the circulation flow rate can be detected (acquired) without using a detection unit such as a flow rate sensor that directly measures the circulation flow. In addition, it is possible to end the process of detecting the circulation flow value extremely quickly, such as only a few seconds after the start of the circulation flow detection process. In addition, since the start time of the timer value is the stop time of the operation of the heating circulation pump 56 for the falling time value to be detected, the start time can be accurately grasped, while the detection returning temperature is also set at the end of the timer value. Since the time point at which the temperature value T (g) is detected, the end can be accurately grasped. As a result, the descent time value to be checked with the relation table can be measured extremely accurately without a control time lag, and the corresponding circulation flow value is derived based on the accurate descent time value. Therefore, it is possible to obtain an accurate circulation flow value.

  When the determination and detection of the circulation flow rate value are completed in step S9, calculation of the remaining hot water amount is executed by the pouring control unit 73 using the circulation flow rate value (step 10). The calculation of the remaining hot water amount is performed by heat quantity calculation using the detection return temperature, the detection going temperature, and the circulation flow value recorded during the refueling period (step S3). That is, the temperature increase width obtained by subtracting the detected return temperature from the detected temperature is multiplied by the circulation flow value to integrate according to the elapsed time, thereby obtaining the integrated heat amount imparted by the reheating heating. Then, the remaining hot water amount may be calculated from this cumulative heat amount and the temperature rise of the return temperature (the temperature of the bath water) during the same elapsed time.

  If the amount of remaining hot water can be grasped by the calculation of step S10, the amount of hot water to be added (or the amount of water) can be grasped up to the set water level of the bathing for bathtub B, so pouring (or pouring) an amount equivalent to this amount of hot water The pouring control unit 73 performs the pouring and ends the pouring (step S11).

  On the other hand, in the determination / confirmation in step S5, when the heat source fluctuation monitoring unit 753 outputs a determination result indicating that a sudden change has occurred on the heat source side immediately before (YES in step S5), the time when the forward temperature is considered stable After temporarily waiting for a preset time tw (for example, 20 to 30 seconds), detection processing of the circulation flow rate after step S6 is started (steps S12 and S6). As a result, the temperature drop to a predetermined set temperature value T (g) can be made as predetermined to accurately measure the fall time value, and the process of detecting the circulation flow rate can be performed accurately and reliably. become.

  As a factor of the heat source side causing rapid fluctuation in the temperature of the high temperature water, there is execution of control according to use of hot water supply by the hot water supply circuit 2 or execution of control according to change of heating capacity in the heating circuit 5. Factors in control of the hot water supply circuit 2 include ignition (commence start) of the hot water supply combustion burner 24 accompanying the use of hot water supply, switching of combustion ability (capability change), and extinguishment (combustion stop). There is switching of the combustion capacity of the combustion burner 52 (capability switching) as. When hot water use occurs and simultaneous use with heating operation occurs, the hot water supply control by the hot water supply control unit 71 is prioritized (hot water supply priority) in the controller 7 and the gas has an opening corresponding to the required combustion capacity for the combustion burner 24 The proportional valve 67 will be controlled. That is, the opening degree of the gas proportional valve 67 which has been controlled according to the required combustion capacity for the heating combustion burner 52 is changed according to the request on the hot water supply side. For this reason, the fuel gas is also supplied to the heating combustion burner 52 at the changed supply pressure, and the combustion heating in the heat exchanger 53 is fluctuated. As a result, the heat source supplied to the reheating heat exchanger 31 The temperature of the high temperature water will also fluctuate rapidly. The same situation can also occur in heating control. That is, in the heating control, when the required combustion capacity changes and the capacity switching to the combustion burner 52 occurs, the temperature of the high-temperature water supplied to the reheating heat exchanger 31 also changes rapidly regardless of the reheating control. It will be done.

  If transition to detection processing of the circulation flow rate is performed while the forward temperature on the refueling side is temporarily destabilized under the influence of such rapid fluctuations on the heat source side, the setting temperature value T (g) is set. Also, the temperature drop characteristic does not match the measured relationship between the measured descent time value and the relationship table, and accurate circulation flow rate detection can not be performed. In order to avoid this and enable accurate detection of circulation flow, it waits for set time tw temporarily, and after waiting for the temperature to go forward and stabilize the temperature, detection processing of circulation flow is started It is

Other Embodiments
The present invention is not limited to the above embodiment, and includes various other embodiments. That is, in the embodiment, when it is determined that the remaining hot water is present in step S2 (YES in step S2), the detection of the circulating flow rate of the additional circulation circuit 3 by the circulation flow rate detection processing unit 75 using the remaining hot water In order to execute the reheating control, the heat source supply to the reheating heat exchanger 31 is stopped to measure the going-down temperature, but the present invention is not limited to this, for example. When normal refueling control is executed, the circulating flow rate is measured by measuring the falling temperature of the temperature from the end of refueling control (when the heat source supply to the reheating heat exchanger 31 is stopped). It is also possible to shift to detection processing. However, also in this case, after confirming step S5 (see FIG. 3) as to whether or not a sudden change has occurred on the heat source side immediately before, it shifts to the detection processing of the circulation flow rate.

  In the above embodiment, the descent time value required to fall to one set temperature value obtained by multiplying the ratio λ is detected, and the circulation flow value corresponding to the one descent time value is determined from the relationship table. However, the present invention is not limited to this, based on two types of set temperature values obtained using two types of λ1 (for example, λ1 = 0.5) and λ2 (for example, λ = 0.67). The two fall time values whose forward temperature has dropped to the set temperature value of are detected, the two circulation flow values corresponding to these two fall time values are determined from the relationship table, these are averaged, and the final A circulation flow value can be obtained. The averaging process enables more accurate detection of the circulation flow rate value.

  Instead of storing, in the table storage unit 752, a plurality of types of relationship tables corresponding to the high and low of the outside air temperature as the relationship tables used in the above embodiment, the descent time value or the descent time value is measured. A correction may be added to the circulation flow rate value determined from the relation table based on the degree of the outside air temperature. 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 temperature drop is large and the time required for the temperature drop will be small. And if the outside air temperature is higher than the reference temperature range, a negative correction is added to the timer value. The correction range may be, for example, plus / minus 0.05 seconds. By adding such correction based on the outside air temperature, it is possible to obtain a circulation flow rate value obtained by the detection process with a higher accuracy (accuracy).

  As the relationship table, a relationship curve or a linear relationship line obtained by linear approximation of the relationship curve may be set, or an equation defining such a relationship curve may be set, or a numerical value table is set. It may be or any of them. In order to set the equation, an approximate equation can be determined from experimental results using, for example, the least squares method, and the relationship curve can be specified in the coordinate system between the fall time value and the circulation flow rate value based on this approximate equation. Or, the approximate expression itself can be set as a relation table. When the numerical value table is set as a relation table, if there is no value of the circulation flow that exactly matches, the value of the circulation flow should be determined by linear interpolation between the values of the adjacent circulation flow. it can.

24 Hot water supply combustion burner 31 Reheating heat exchanger 32 Reheating circulation path 36 Forward temperature sensor (forward temperature detection means)
52 Heating burner for heating 55 Hot water circuit (heating circuit)
67 Gas proportional valve (fuel adjustment valve)
75 Circulating flow rate detection processing unit 753 Heat source fluctuation monitoring unit B Bathtub

Claims (5)

A hot water supply combustion burner for burning and heating water for hot water supply, a heating combustion burner for heating a heat medium circulatingly supplied to a heating circuit as a heat source for hot water heating, and the heating combustion burner as a heat source And a reheating heat exchanger for reheating and heating the hot and cold water by liquid-liquid heat exchange, receiving circulating supply of hot water from the bath through the reheating circulation path, and A circulation flow rate detection processing unit for detecting a circulation flow rate of hot water circulated in the reheating circulation path through the reheating heat exchanger according to a control process, the hot water supply combustion burner and the heating heater The combustion burner is configured to receive combustion supply via a common fuel adjustment valve, and the circulation flow rate detection processing unit is configured to maintain the hot water circulation in the reheating circulation path while the heating is being performed. The circulation based on the temperature drop of the hot water passing through the reheating heat exchanger to the bath with the circulation supply of the heat source to the reheating heat exchanger through the ring path shut off. A complex heat source machine configured to detect a flow rate, wherein
The circulation flow rate detection processing unit monitors at least one control condition of the hot water supply combustion burner and the heating combustion burner, and starts the circulation flow rate detection processing. When control is performed to bring about rapid fluctuations in the temperature of the circulating heat medium, the process of detecting the circulation flow rate is started after waiting for a time set in advance as the time required for the traveling temperature to stabilize. Is configured as
A complex heat source machine characterized by It is a compound heat source machine according to claim 1,
The circulation flow rate detection processing unit either starts the combustion of the hot water supply combustion burner, switches the combustion capacity, or stops the combustion when the hot water supply combustion burner is simultaneously burned with the heating combustion burner. A complex heat source configured to stand by for the set time before the start of the detection process of the circulation flow rate, assuming that the control to bring about a sudden change in the heat medium temperature is executed when the control including the step is executed. Machine. The combined heat source machine according to claim 1 or 2, wherein
When the control for switching the combustion capacity of the heating combustion burner is executed while the heat medium is being circulated and supplied to the reheating heat exchanger, the circulation flow rate detection processing unit is suddenly set to the heat medium temperature. The complex heat source machine configured to stand by for the set time before the start of the detection process of the circulation flow rate, as the control that causes fluctuation is executed. A heating combustion burner for heating a heat medium circulatingly supplied to a heating circuit as a heat source for hot water heating, and a circulation supply of a heat medium heated by the heating combustion burner as a heat source A reheating heat exchanger for reheating and heating the hot water by liquid-liquid heat exchange upon receiving a circulating supply of hot and cold water from a bath through the passage, and circulating through the reheating heat exchanger through the reheating heat exchanger through the reheating heat exchanger. And a circulation flow rate detection processing unit for detecting the circulation flow rate of the hot and cold water by control processing, and the circulation flow rate detection and processing unit maintains the hot water circulation in the recurrent circulation path. However, in a state where the circulation supply of the heat source to the reheating heat exchanger through the heating circuit is shut off, the temperature drop of the hot water passing through the reheating heat exchanger toward the bathtub A composite heat source machine that is configured to detect the circulating flow rate based,
The circulation flow rate detection processing unit monitors the control state of the heating combustion burner, and when starting the detection process of the circulation flow rate, the temperature of the heat medium circulatingly supplied to the reheating heat exchanger fluctuates rapidly When the control that brings about is performed, the detection process of the circulation flow rate is started after waiting for a time set in advance as the time required for the going temperature to stabilize.
A complex heat source machine characterized by It is a compound heat source machine according to claim 4,
When the control for switching the combustion capacity of the heating combustion burner is executed while the heat medium is being circulated and supplied to the reheating heat exchanger, the circulation flow rate detection processing unit is suddenly set to the heat medium temperature. The complex heat source machine configured to stand by for the set time before the start of the detection process of the circulation flow rate, as the control that causes fluctuation is executed.

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