JP7328876B2 - Heating water heater - Google Patents

Description

The present invention uses a common heat medium to heat the water supplied to the hot water heat exchanger by circulating the heat medium to the heating terminal and heating operation by circulating the heat medium to the heating terminal. The present invention relates to a heating and hot water supply apparatus capable of performing a hot water supply operation of generating hot water by heating through heat exchange with a medium.

It is possible to perform a heating operation in which a heat medium is heated by a heating means such as a burner, and the heat medium is circulated to the heating terminal by a circulation pump to perform heating. 2. Description of the Related Art There is known a heating and hot water supply apparatus capable of performing a hot water supply operation in which water supplied to a heat exchanger is heated by heat exchange with a heat medium to generate hot water (Patent Document 1). In such a heating and hot water supply device, a distribution means such as a three-way valve that can change the distribution ratio of distributing a common heat medium to a heating circuit that circulates the heat medium to the heating terminal and a hot water supply circuit that circulates the heat medium to the hot water heat exchanger. It is possible to switch between the heating operation and the hot water supply operation by controlling the distribution means. Further, a temperature detection means for detecting the temperature of the heat medium is provided, and the heating by the heating means is controlled according to the temperature of the heat medium. to stop.

JP 2018-185082 A

However, in such a heating and hot water supply system, the flow rate of the heat medium may be throttled on the heating terminal side during the heating operation, and as the total flow rate of the heat medium supplied to the heating means is greatly reduced, the heat Even if the heating amount of the heating means for heating the medium is suppressed, there is a time lag between the decrease in the flow rate and the suppression of the heating amount, and the temperature of the heating medium rises. When the temperature of the heat medium reaches the stop temperature, although the heating by the heating means is stopped, the temperature of the heat medium rises due to residual heat of the heating means even after the stop (so-called post-boiling), which causes an overshoot. There is a problem in that the temperature of the heat medium detected by the temperature detection means fluctuates and it takes time to stabilize at the set temperature due to the circulation of the heat medium that is locally heated to a high temperature at a small flow rate. Ta.

The present invention has been made in response to the above-described problems of the conventional technology. To provide a technology capable of quickly alleviating temperature fluctuations and shortening the time required for stabilization.

In order to solve the above problems, the heating and hot water supply apparatus of the present invention employs the following configuration. i.e.
Using a common heat medium, a heating operation in which the heat medium is circulated through the heating terminal for heating, and a heating operation in which the heat medium is circulated through the hot water supply heat exchanger to heat the water supplied to the hot water supply heat exchanger. A heating and hot water supply apparatus capable of performing a hot water supply operation for generating hot water by heating by heat exchange with a medium,
heating means for heating the heat medium;
a circulation pump for sending the heat medium;
a temperature detecting means for detecting the temperature of the heat medium;
heating control means for controlling heating of the heating means according to the temperature of the heat medium;
It is possible to change the distribution ratio for distributing the common heat medium by switching the opening degrees of the heating circuit that circulates the heat medium to the heating terminal and the hot water supply circuit that circulates the heat medium to the hot water supply heat exchanger. distribution means and
Distribution control means for controlling switching of the distribution means,
When the hot water supply circuit is closed to stop the hot water supply operation, and the heating circuit is opened to stop the heating of the heating means during the execution of the heating operation, the temperature of the heat medium is equal to or higher than a predetermined temperature. Then, the distribution control means controls the distribution means so as to open the hot water supply circuit and increase the degree of opening.

In such a heating and hot water supply apparatus of the present invention, if the temperature of the heating medium rises while the hot water supply operation is stopped and only the heating operation is performed , although the heating of the heating means is stopped, It is suspected that the flow rate of the heat medium is throttled on the heating terminal side, the total flow rate of the heat medium supplied to the heating means is greatly reduced, and the temperature of the heat medium is locally increased due to post-boiling. Therefore, if the distribution means is controlled to open the hot water supply circuit to increase the opening degree, the flow rate of the heat medium flowing through the hot water supply circuit is increased, and the total flow rate of the circulating heat medium can be secured. The heat medium, which had been at a high temperature, diffuses, and compared to the case where the opening degree is not changed while the hot water supply circuit is closed , the fluctuation in the temperature of the heat medium is quickly alleviated, and it takes time until the temperature of the heat medium stabilizes. It is possible to shorten the time.

In the above-described heating and hot water supply apparatus of the present invention, when the temperature of the heat medium flowing out from the location where the heat medium is heated by the heating means reaches or exceeds the first predetermined temperature, the distribution means is controlled to increase the opening degree of the hot water supply circuit. good too.

Since the effect of post-boiling due to residual heat after the heating of the heating means is stopped is first noticeable in the temperature (outgoing temperature) of the heat medium flowing out from the heating location, the incoming temperature must be equal to or higher than the first predetermined temperature. By controlling the distribution means to increase the degree of opening of the hot water supply circuit, it is possible to quickly suppress an increase (overshoot) in the temperature of the heat medium.

Further, in the heating and hot water supply apparatus of the present invention, when the temperature of the heat medium flowing into the portion where the heat medium is heated by the heating means reaches or exceeds the second predetermined temperature, the distribution means is controlled so as to increase the degree of opening of the hot water supply circuit. may

As the locally heated heat medium circulates, the temperature of the heat medium flowing into the heating point (return temperature) rises, and the high temperature heat medium flows slowly into the heating point at a low flow rate. The risk of damage to the heated point then increases. Therefore, when the return temperature of the heat medium reaches or exceeds the second predetermined temperature, the distribution means is controlled to increase the opening of the hot water supply circuit, thereby securing the total flow rate of the heat medium flowing into the heating portion. can reduce the risk of damage to hot spots.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed the structure of the heating and hot water supply apparatus 1 of a present Example. FIG. 3 is an explanatory diagram showing the configuration of a heating terminal according to the embodiment; 2 is a cross-sectional view showing the configuration of a three-way valve 29 of this embodiment. FIG. 4 is a flowchart of processing during heating operation executed by the controller 40 of the embodiment. 5 is a flow chart of temperature change mitigation processing according to the present embodiment. FIG. 4 is a cross-sectional view showing an intermediate state of the three-way valve 29 of this embodiment; FIG. 8 is an explanatory diagram showing how the temperature of the heat medium fluctuates due to the flow rate of the heat medium being throttled on the heating terminal side during execution of the heating operation.

FIG. 1 is an explanatory diagram showing the configuration of a heating and hot water supply system 1 of this embodiment. As shown in the figure, the heating and hot water supply system 1 includes a combustion unit 4 inside which is covered with a housing 2 and has a built-in burner 3 for burning a mixed gas of fuel gas and combustion air. A combustion fan 5 is connected to the combustion unit 4 , and the mixed gas is fed by the combustion fan 5 .

On the intake side of the combustion fan 5, a junction 6 is provided for joining an air supply passage 7 for supplying combustion air and a gas supply passage 8 for supplying fuel gas. The gas supply path 8 is provided with an on-off valve (not shown) that opens and closes the gas supply path 8, and a zero governor 9 that lowers the pressure of the fuel gas pressure-fed from the upstream side to atmospheric pressure. The confluence portion 6 has a built-in control valve, which makes it possible to adjust the ratio between the combustion air and the fuel gas flowing into the combustion fan 5 . When the combustion fan 5 is driven, the air in the housing 2 and the fuel gas on the downstream side of the zero governor 9 in the gas supply passage 8 pass through the confluence 6 and are sucked into the combustion fan 5 at a predetermined ratio, resulting in a mixed gas. It is sent to the combustion unit 4.

In the combustion unit 4, a built-in burner 3 burns the mixed gas. In the illustrated example, the mixed gas is jetted downward from the burner 3 to form a downward flame and send the combustion exhaust downward. The combustion fan 5 is electrically connected to a controller 40 that controls the entire heating and hot water supply system 1, and the controller 40 changes the rotational speed of the combustion fan 5 according to the amount of heating required. The amount of combustion in the burner 3 is controlled. The burner 3 of this embodiment corresponds to the "heating means" of the invention, and the controller 40 of this embodiment corresponds to the "heating control means" of the invention.

The combustion unit 4 also includes a spark plug 11 that emits sparks by high-voltage discharge, a flame rod 12 that detects the flame (ignition) of the burner 3 , and a reverse current that prevents backflow from the combustion unit 4 to the combustion fan 5 . A stop valve 13 is provided. Spark plug 11 and flame rod 12 are electrically connected to controller 40 .

A first heat exchanger 15 is provided below the burner 3 , and a second heat exchanger 16 is provided below the first heat exchanger 15 . Combustion exhaust gas generated by combustion in the burner 3 is sent downward and passes through the first heat exchanger 15 and the second heat exchanger 16 . At this time, the first heat exchanger 15 recovers sensible heat from the combustion exhaust gas, and the second heat exchanger 16 recovers latent heat from the combustion exhaust gas.

After passing through the first heat exchanger 15 and the second heat exchanger 16 , the combustion exhaust passes through the exhaust duct 17 and is discharged from the exhaust port 18 projecting upward from the housing 2 . In the illustrated example, an air supply port 19 is provided in the upper portion of the housing 2 , and air taken into the housing 2 through the air supply port 19 is sucked into the combustion fan 5 through the air supply passage 7 .

The upstream side of the first heat exchanger 15 is connected to the downstream side of the second heat exchanger 16 . In addition, the downstream side of the first heat exchanger 15 is connected to the upstream side of a heating terminal described later via a forward passage 21, and the upstream side of the second heat exchanger 16 is connected to the downstream side of a heating terminal described later. and through a return passage 22. The return passage 22 includes a circulation pump 23 for sending a heat medium such as hot water toward the second heat exchanger 16 and a return pump for detecting the temperature of the heat medium flowing into the second heat exchanger 16 (hereinafter referred to as return temperature). A temperature sensor 24 is provided. Circulation pump 23 and return temperature sensor 24 are electrically connected to controller 40 . The return temperature sensor 24 of this embodiment corresponds to the "temperature detection means" of the present invention.

As described above, in the second heat exchanger 16, latent heat is recovered from the combustion exhaust gas of the burner 3, and the heat medium sent to the second heat exchanger 16 by the operation of the circulation pump 23 is preliminarily prepared with the recovered heat. After being heated, it is sent to the first heat exchanger 15 . In the first heat exchanger 15, the heat medium is heated by the sensible heat recovered from the combustion exhaust gas of the burner 3, and the hot heat medium is supplied to the heating terminal through the forward passage 21. The forward passage 21 is provided with a forward temperature sensor 25 that detects the temperature of the heat medium flowing out of the first heat exchanger 15 (hereinafter, forward temperature). The forward temperature sensor 25 is electrically connected to the controller 40. It is connected. Although details will be described later, the controller 40 determines the required amount of heating according to the temperature of the heat medium detected by the incoming temperature sensor 25 and controls combustion in the burner 3 . The forward temperature sensor 25 of this embodiment corresponds to the "temperature detection means" of the present invention. Also, the second heat exchanger 16 and the first heat exchanger 15 of the present embodiment correspond to the "heating point" of the present invention.

The heat medium cooled by passing through the heating terminal returns to the circulation pump 23 through the return passage 22 and is sent to the second heat exchanger 16 again. The circulating pump 23 of this embodiment feeds the heating medium while maintaining a constant number of revolutions. The heat medium to be circulated in this manner is not limited to hot water, and silicone oil or the like may be used. In addition, the first heat exchanger 15 is provided with an overheat switch 26 avoiding a position where combustion exhaust comes into contact. The overheat switch 26 is a safety device composed of a bimetal switch or the like, and is activated when the temperature of the heat medium reaches a predetermined operating temperature (around 97 degrees in this embodiment) for a predetermined period of time. Combustion at 3 is forcibly stopped (supply of fuel gas is cut off).

A branch passage 27 branches from the downstream side of the forward temperature sensor 25 of the forward passage 21 and is connected to the return passage 22 upstream of the circulation pump 23 . A hot water supply heat exchanger 28 is provided in the branch passage 27 , and a three-way valve 29 is provided in a connecting portion between the branch passage 27 and the return passage 22 . The configuration of the three-way valve 29 will be described later using another diagram, but the heat medium flowing out of the first heat exchanger 15 is routed through the heating terminal (heating circuit) and through the hot water supply heat exchanger 28 (hot water supply circuit) can be changed by the three-way valve 29 . The three-way valve 29 is electrically connected with the controller 40 . The three-way valve 29 of this embodiment corresponds to the "distribution means" of the invention, and the controller 40 of this embodiment corresponds to the "distribution control means" of the invention.

The hot water supply heat exchanger 28 is a liquid-liquid heat exchanger, to which a water supply passage 30 and a hot water outlet passage 31 are connected. The clean water supplied to the hot water heat exchanger 28 through the water supply passage 30 is heated by heat exchange with the heat medium in the hot water heat exchanger 28 to become hot water, and flows out to the hot water outlet passage 31 . The water supply passage 30 is provided with a water volume sensor 32 for measuring the flow rate of the clean water flowing into the heating and hot water supply system 1, a water volume servo 33 for adjusting the flow rate of the clean water, and a water supply temperature sensor 34 for detecting the temperature of the clean water. It is The hot water supply passage 31 is provided with a hot water supply heat exchanger outlet temperature sensor 35 for detecting the temperature of hot water immediately after flowing out from the hot water supply heat exchanger 28 . The water volume sensor 32 , water volume servo 33 , water supply temperature sensor 34 , and hot water supply heat exchanger outlet temperature sensor 35 are electrically connected to the controller 40 .

Further, in the heating and hot water supply apparatus 1 of this embodiment, the water supply passage 30 and the hot water supply passage 31 are connected by a bypass passage 36 . A part of the clean water that has flowed into the heating and hot water supply device 1 can pass through the bypass passage 36 without being supplied to the hot water supply heat exchanger 28 , and the rest is supplied to the hot water supply heat exchanger 28 . The hot water heated by the hot water heat exchanger 28 is mixed with clean water that has passed through the bypass passage 36 and flows out of the heating and hot water supply device 1 . A bypass servo 37 is provided at the connecting portion between the bypass passage 36 and the hot water outlet passage 31, and the mixing ratio of the hot water heated by the hot water heat exchanger 28 and the tap water passing through the bypass passage 36 is controlled by the bypass servo. 37 can be modified. Bypass servo 37 is electrically connected to controller 40 .

A hot water temperature sensor 38 for detecting the temperature of hot water flowing out from the heating and hot water supply device 1 is provided downstream of the bypass servo 37 in the hot water passage 31 . As described above, when part of the tap water from the water supply passage 30 passes through the bypass passage 36 without passing through the hot water supply heat exchanger 28 and joins the hot water supply passage 31, the temperature detected by the hot water supply temperature sensor 38 is the same as the temperature at the hot water supply heat exchange outlet. Since the temperature is lower than the temperature detected by temperature sensor 35 , by adjusting the mixture ratio with bypass servo 37 , fluctuations in the temperature of hot water flowing out from heating and hot water supply apparatus 1 can be suppressed.

Furthermore, a hot water supply remote controller 41 and a heating remote controller 42 are connected to the controller 40 . By operating the hot water supply remote control 41, the user can switch the hot water supply operation between the ON state and the OFF state and set the hot water supply temperature. In addition, the user can operate the heating remote control 42 to instruct the start or stop of the heating operation, or to set the heating temperature.

FIG. 2 is an explanatory diagram showing the configuration of the heating terminal of this embodiment. First, in the example shown in FIG. 2(a), a floor heater 50 is connected as a heating terminal. The floor heating system 50 includes a meandering pipe 51, which is connected to a forward passage 21 on the upstream side and to a return passage 22 on the downstream side. Then, the heat medium radiates heat while passing through the pipe 51 to warm the surroundings. Such floor heating 50 may be installed in each of a plurality of rooms.

FIG. 2(b) shows an example with three floor heatings 50a, 50b, 50c, and these three floor heatings 50a to 50c are connected in parallel with each other. That is, the forward passage 21 is branched into three and connected to the upstream side of each of the floor heatings 50a to 50c, and the return passage 22 connected to the downstream side of each of the floor heatings 50a to 50c is one. , and are connected to the three-way valve 29 .

Each floor heating unit 50 is provided with a switching valve 52 for opening and closing a pipe 51, as shown in FIG. 2(a). It is possible to switch between circulating the heat medium and stopping the circulation. For example, by opening all the switching valves 52, the heating medium can be circulated through the three floor heaters 50a to 50c. On the other hand, in order to stop the circulation of the heat medium for any of the floor heaters 50 that are not used, the corresponding switching valve 52 should be closed. Such operation of the switching valve 52 may be manually performed by the user, or may be automatically performed by controlling the floor heating 50 . Note that the heating terminal is not limited to the floor heating 50, and may be a fan convector (room heater) or the like.

FIG. 3 is a cross-sectional view showing the configuration of the three-way valve 29 of this embodiment. As shown in the figure, a valve chamber 60 communicating in three directions is formed inside the three-way valve 29 . In the illustrated example, the branch passage 27 is connected to the left of the valve chamber 60, the heating terminal side of the return passage 22 (hereinafter referred to as the terminal side return passage 22a) is connected to the right, and the circulation pump of the return passage 22 is connected to the upper side. 23 side (hereinafter referred to as pump-side return passage 22b) is connected.

The valve chamber 60 accommodates a hot water supply side valve body 61 for opening and closing the branch passage 27 and a heating side valve body 62 for opening and closing the terminal side return passage 22a. The side valve bodies 62 are attached in opposite directions to a moving shaft 63 capable of reciprocating in the left-right direction. The moving shaft 63 is driven by a drive motor 64, and a stepping motor is adopted as the drive motor 64 in this embodiment.

FIG. 3A shows a state in which the moving shaft 63 moves rightward, the heating side valve body 62 closes the terminal side return passage 22a, and the hot water supply side valve body 61 opens the branch passage 27. . In this state, the heat medium flowing out of the first heat exchanger 15 due to the operation of the circulation pump 23 circulates through the hot water supply heat exchanger 28 without being distributed to the heating terminal (floor heating 50). Hot water supply operation is performed.

On the other hand, when the moving shaft 63 moves leftward, the hot water supply side valve body 61 closes the branch passage 27 and the heating side valve body 62 opens the terminal side return passage 22a as shown in FIG. Become. In this state, the heat medium flowing out of the first heat exchanger 15 due to the operation of the circulation pump 23 is not distributed to the hot water heat exchanger 28, but circulates through the heating terminal (floor heating 50). heating operation is performed.

In the three-way valve 29 of this embodiment, the branch passage 27 and the pump-side return passage 22b are connected via a connection passage 65, and the connection passage 65 is provided with a differential pressure valve 66. The differential pressure valve 66 includes a valve element 67 that opens and closes the connection passage 65 and a valve closing spring 69 that biases the valve element 67 against the valve seat 68 from the return passage 22 side. During the hot water supply operation, the hot water supply side valve body 61 opens the branch passage 27 as shown in FIG. The valve body 67 is pressed against the valve seat 68 by the urging force of the valve closing spring 69 to close the valve.

On the other hand, as described above, the floor heater 50 of this embodiment is provided with the switching valve 52 for opening and closing the pipe 51, and the hot water supply side valve body 61 closes the branch passage 27 as shown in FIG. When the switching valve 52 is closed to stop the circulation of the heat medium in the floor heating 50 during the heating operation, the flow rate of the heat medium circulating in the return passage 22 decreases, so the branch passage 27 communicating with the forward passage 21 is closed. The pressure becomes greater than the pressure in the pump-side return passage 22b, creating a pressure difference. When the pressure difference exceeds the threshold value, the differential pressure valve 66 opens the valve body 67 against the urging force of the valve closing spring 69 and moves away from the valve seat 68. Through 65, the heat medium flows to the pump-side return passage 22b. By opening the differential pressure valve 66, even if the switching valves 52 of all the three floor heating units 50a to 50c are closed, the minimum flow rate of the heat medium circulating in the return passage 22 is maintained. can be avoided to prevent failures.

Even if the total flow rate of the circulating heat medium decreases in this way, since there is no heat medium flow rate sensor or the like, the burner 3 continues until the incoming temperature sensor 25 detects an increase in the temperature of the heat medium. By maintaining the combustion amount (heating amount), the heat medium is excessively heated and the temperature of the heat medium rises sharply. Then, when the temperature detected by the forward temperature sensor 25 reaches a predetermined stop temperature (87 degrees in this embodiment), it is assumed that some kind of abnormality has occurred, and combustion in the burner 3 is stopped. However, even after the combustion in the burner 3 is stopped, overshoot occurs due to the temperature of the heat medium being increased by the residual heat of the combustion unit 4 (so-called after-boiling). As the heat medium locally heated to a high temperature circulates at a small flow rate, the temperature of the heat medium detected by the forward temperature sensor 25 and the return temperature sensor 24 fluctuates and does not stabilize easily. In addition, when the overheat switch 26 is activated by the high-temperature heat medium, the supply of fuel gas is interrupted and the heating operation is prohibited, so it takes time to restart.

Therefore, in the heating and hot water supply apparatus 1 of the present embodiment, even if the circulation of the heat medium is stopped (the flow rate of the heat medium is throttled) on the heating terminal (floor heating 50) side during the execution of the heating operation, the heat medium In order to quickly alleviate the temperature fluctuations, the controller 40 executes the following processing during heating operation.

FIG. 4 is a flowchart of processing during heating operation executed by the controller 40 of this embodiment. This processing during heating operation is executed when the heating operation is started by the user's operation of the heating remote control 42 . With the start of the heating operation, the three-way valve 29 is set to the heating operation state shown in FIG.

In the process during heating operation, first, the combustion amount (heating amount) of the burner 3 is controlled (STEP 1). In the heating and hot water supply apparatus 1 of the present embodiment, the target temperature of the heat medium is determined based on the heating temperature set by the heating remote control 42, and the forward temperature of the heat medium detected by the forward temperature sensor 25 is the target temperature. The amount of combustion of the burner 3 is set so that the amount of combustion of the burner 3 is set, and the rotation speed of the combustion fan 5 (the amount of supply of the mixed gas) is changed according to the amount of combustion. In addition, when the incoming temperature of the heat medium exceeds the target temperature even if the amount of combustion in the burner 3 is minimized, intermittent combustion control is performed to repeat combustion and extinguishing in the burner 3. For example, a temperature range is set with the target temperature as the middle value. Combustion in burner 3 may be resumed when temperature is reached.

Subsequently, it is determined whether or not the forward temperature of the heat medium detected by the forward temperature sensor 25 is equal to or higher than a predetermined stop temperature (87 degrees) (STEP 2). As described above, the stop temperature is set to determine the occurrence of some kind of abnormality. If the incoming temperature of the heat medium is less than the stop temperature (STEP 2: no), then the heating operation stop instruction is issued. It is determined whether or not there is (STEP 3). When the user operates the heating remote controller 42 to issue an instruction to stop the heating operation (STEP 3: yes), the heating operation is stopped (STEP 4), and the process during heating operation in FIG. 4 ends. In this STEP4, after stopping the combustion in the burner 3, the circulation pump 23 is stopped. After that, when the user operates the heating remote control 42 to give an instruction to start the heating operation, the heating operation is resumed, and the process during the heating operation of FIG. 4 is executed again.

On the other hand, if there is no command to stop the heating operation (STEP 3: no), then it is determined whether or not there is a request for the hot water supply operation (STEP 5). The controller 40 of the present embodiment is in the ON state of the hot water supply operation by operating the hot water supply remote control 41, and when the user opens the hot water supply valve (not shown) and the flow rate of clean water measured by the water flow sensor 32 exceeds a predetermined amount, It is determined that there is a request for hot water supply operation.

If the hot water supply operation is requested (STEP 5: yes), the heating operation is shifted to the hot water supply operation (STEP 6), and the process during the heating operation of FIG. 4 ends. In this STEP6, the three-way valve 29 is switched from the heating operation state of FIG. 3(b) to the hot water supply operation state of FIG. 3(a). After that, when there is a request to stop the hot water supply operation, the hot water supply operation is returned to the heating operation, and the process during the heating operation of FIG. 4 is executed again.

On the other hand, if there is no request for hot water supply operation (STEP 5: no), return to STEP 1, control the combustion amount (heating amount) of the burner 3, It is determined whether or not there is (STEP 2). Then, if the incoming temperature of the heat medium is equal to or higher than the stop temperature (STEP 2: yes), the following temperature fluctuation mitigation process is executed (STEP 7).

FIG. 5 is a flow chart of the temperature change mitigation process of this embodiment. When the temperature fluctuation mitigation process is started, first, the combustion in the burner 3 is stopped by cutting off the supply of the fuel gas (STEP8). Next, it is determined whether or not the forward temperature of the heat medium detected by the forward temperature sensor 25 is equal to or higher than the first predetermined temperature (STEP 9). This first predetermined temperature is set to a temperature higher than the stop temperature, and is set to 90 degrees in this embodiment.

If the incoming temperature of the heat medium is lower than the first predetermined temperature (STEP 9: no), then it is determined whether the return temperature of the heat medium detected by the return temperature sensor 24 is equal to or higher than the second predetermined temperature. (STEP 10). This second predetermined temperature is set to a temperature lower than the first predetermined temperature and the stop temperature, and is set to 80 degrees in this embodiment.

If the return temperature of the heat medium is lower than the second predetermined temperature (STEP 10: no), it is determined whether or not a predetermined time (for example, 120 seconds) has passed since the combustion in the burner 3 was stopped in STEP 8 ( STEP 11). If the predetermined time has not yet passed (STEP 11: no), return to STEP 9, determine whether the forward temperature of the heat medium is equal to or higher than the first predetermined temperature (STEP 9), and determine whether the return temperature of the heat medium is The determination (STEP 10) of whether or not the time is equal to or longer than the second predetermined time is repeated.

Then, if a predetermined time has elapsed since the combustion in the burner 3 was stopped while the forward temperature of the heat medium is less than the first predetermined temperature and the return temperature of the heat medium is less than the second predetermined temperature (STEP 11 : yes), it is determined whether or not the incoming temperature of the heat medium has decreased below the target temperature (STEP 12). As described above, the target temperature of the heat medium is determined based on the heating temperature set by the heating remote control 42, and when the incoming temperature of the heat medium is equal to or higher than the target temperature (STEP 12: no), the target temperature It will be in a standby state until it drops below.

After that, when the incoming temperature of the heat medium is lower than the target temperature (STEP 12: yes), the combustion in the burner 3 is resumed (STEP 13), the temperature fluctuation mitigation process in FIG. Return to processing during operation. In the process during heating operation, when returning from the temperature change mitigation process (STEP7), the process returns to STEP1, and the combustion amount (heating amount) of the burner 3 is controlled.

On the other hand, in the temperature fluctuation mitigation process of FIG. (STEP 9: yes) If the return temperature of the heat medium is equal to or higher than the second predetermined temperature (80 degrees) (STEP 10: yes), the three-way valve 29 is moved to the intermediate state (STEP 14).

As described above, when the flow rate of the heat medium is throttled on the heating terminal (floor heating 50) side during the heating operation, the temperature of the heat medium rises sharply as the total flow rate of the circulating heat medium decreases, and the burner 3 Even after the combustion is stopped, the temperature of the heat medium may rise due to post-boiling and an overshoot may occur. It appears as an increase in the forward temperature detected by the return temperature sensor 24 and an increase in the return temperature detected by the return temperature sensor 24 . Conversely, if the forward temperature and return temperature of the heat medium increase even though the burner 3 has stopped burning during the heating operation, the flow rate of the heat medium at the heating terminal side will increase. There is a high possibility that the total flow rate of the circulating heat medium is reduced due to the throttling, and the temperature of the heat medium is locally high due to post-boiling.

When the temperature of the heat medium rises while the burner 3 is not burning during the heating operation, the switch valve 52 is closed and the differential pressure valve 66 is opened in all the three floor heaters 50a to 50c. Not only when the heat medium with the lowest flow rate is circulated by Even if the differential pressure valve 66 does not open at , the total flow rate of the circulating heat medium is greatly reduced, so a similar situation can occur.

FIG. 6 is a cross-sectional view showing an intermediate state of the three-way valve 29 of this embodiment. As illustrated, in the intermediate state of the three-way valve 29, the branch passage 27 is opened by stopping the moving shaft 63 between the hot water supply operation state of FIG. 3(a) and the heating operation state of FIG. 3(b). and terminal-side return passage 22a are opened, and the degree of opening becomes substantially the same. In this state, the heat medium flowing out of the first heat exchanger 15 due to the operation of the circulation pump 23 is directed to both the route (hot water supply circuit) passing through the hot water supply heat exchanger 28 and the route (heating circuit) passing through the heating terminal. It can be distributed and circulated. Therefore, even if the flow rate of the heat medium is throttled on the heating terminal side, the total flow rate of the circulating heat medium can be ensured by the heat medium flowing through the hot water supply circuit. In the intermediate state of the three-way valve 29, the branch passage 27 communicates with the pump-side return passage 22b, so no pressure difference occurs and the differential pressure valve 66 is closed.

When the three-way valve 29 is placed in the intermediate state in this manner, it is determined whether or not the return condition is established (STEP 15). In this embodiment, the return condition is set such that the forward temperature of the heat medium is lower than the target temperature and stabilizes, and the return temperature of the heat medium is also stable. If the return condition is not satisfied yet (STEP 15: no), it will be in a standby state until the return condition is satisfied.

After that, when the return condition is satisfied (STEP15: yes), the return process is performed (STEP16), the temperature change mitigation process of FIG. 5 is terminated, and the process during heating operation of FIG. 4 is resumed. In STEP 16, the three-way valve 29 is moved from the intermediate state shown in FIG. 6 to the heating operation state shown in FIG. 3(b), and then the burner 3 resumes combustion.

FIG. 7 is an explanatory diagram showing how the temperature of the heat medium fluctuates due to the flow rate of the heat medium being throttled on the heating terminal side during execution of the heating operation. In the graph of FIG. 7, the horizontal axis represents time, and the vertical axis represents the temperature of the heat medium. there is

First, FIG. 7(a) shows, for comparison, the case where the three-way valve 29 is kept in the heating operation state, unlike the present embodiment. In the illustrated example, the flow of the heat medium is completely blocked on the heating terminal (floor heating 50) side during execution of the heating operation, and although the circulation of the heat medium is maintained by opening the differential pressure valve 66, the circulating heat medium The total flow rate of is greatly reduced. At this time, the combustion amount (heating amount) in the burner 3 is maintained, so that the incoming temperature of the heat medium flowing out of the first heat exchanger 15 rises sharply, and when it reaches the stop temperature Ta, combustion in the burner 3 is stopped. Although it stops (extinguishes the fire), the temperature rises due to post-boiling and an overshoot occurs.

Also, the return temperature of the heat medium flowing into the second heat exchanger 16 rises with a delay from the going temperature due to the circulation of the locally heated heat medium while the total flow rate decreases. As described above, the first heat exchanger 15 of this embodiment is provided with the overheat switch 26, and the return temperature of the heat medium before flowing into the second heat exchanger 16 reaches the operating temperature of the overheat switch 26. If it exceeds Tb, the overheat switch 26 is likely to operate when the heat medium passes through the first heat exchanger 15 at a low flow rate over time through the second heat exchanger 16 .

Then, although the incoming temperature of the heat medium temporarily turned downward due to the consumption of the residual heat of the combustion unit 4, the temperature became locally high and the heat medium that was sent out earlier circulated, and the high temperature was maintained. By returning to the first heat exchanger 15 as it is, the incoming temperature of the heat medium rises again. This effect also appears on the return temperature of the heat medium with a delay, so that the forward temperature and the return temperature of the heat medium alternately rise and fall, and are not stabilized easily.

On the other hand, FIG. 7B shows the case where the three-way valve 29 is moved to the intermediate state in this embodiment. Also in FIG. 7(b), the flow of the heat medium is blocked at the heating terminal (floor heating 50) during the execution of the heating operation, and the total flow rate of the circulating heat medium is greatly reduced. rises sharply, reaches the stop temperature Ta, and even after the combustion in the burner 3 is stopped (extinguished), the forward temperature rises due to post-boiling and overshooting is the same as in Fig. 7(a). be.

However, in FIG. 7B, the three-way valve 29 is moved from the heating operation state to the intermediate state based on the return temperature of the heat medium becoming equal to or higher than the second predetermined temperature T2. By increasing the opening of the branch passage 27 (hot water supply circuit) while decreasing the opening of the terminal-side return passage 22a (heating circuit) in this way, even if the flow of the heat medium is interrupted on the heating terminal side, hot water supply The flow rate of the heat medium flowing through the circuit increases. As a result, since the total flow rate of the circulating heat medium is ensured, the locally heated heat medium diffuses, and compared to FIG. is quickly relieved, and the time required for the temperature of the circulating heat medium to stabilize is shortened.

In addition, in FIG. 7B, the period during which the return temperature of the heat medium exceeds the operating temperature Tb of the overheat switch 26 is significantly shortened compared to FIG. The time of exposure to the heat medium is short, and the possibility that the overheat switch 26 will operate is reduced.

As described above, in the heating and hot water supply apparatus 1 of the present embodiment, when the incoming temperature of the heat medium reaches the stop temperature (87 degrees) during execution of the heating operation and the combustion in the burner 3 is stopped, the heat medium When the forward temperature of the heat medium reaches a first predetermined temperature (90 degrees) or higher, or the return temperature of the heat medium reaches a second predetermined temperature (80 degrees) or higher, the three-way valve 29 is moved to the intermediate state. . When the temperature of the heat medium rises even though the burner 3 has stopped burning, the flow rate of the heat medium is throttled at the heating terminal side, and the total flow rate of the circulating heat medium is greatly reduced. , it is suspected that the temperature of the heat transfer medium is locally high due to post-boiling. Therefore, if the opening of the branch passage 27 (hot water supply circuit) is increased by moving the three-way valve 29 from the heating operation state to the intermediate state, the flow rate of the heat medium flowing through the hot water supply circuit is increased. Since the total flow rate can be secured, the locally heated heat medium diffuses, and compared to the case where the three-way valve 29 is not moved, the fluctuation in the temperature of the heat medium is quickly mitigated, and the heat medium is dissipated. It is possible to shorten the time until the temperature stabilizes.

In addition, the effect of post-boiling due to the residual heat of the combustion unit 4 after stopping the combustion in the burner 3 first appears conspicuously in the forward temperature of the heat medium flowing out from the first heat exchanger 15, so the forward temperature is equal to the stop temperature. A three-way valve 29 increases the opening of the branch passage 27 (hot water supply circuit) based on the fact that the temperature reaches a first predetermined temperature higher than the first predetermined temperature, thereby quickly suppressing the temperature rise (overshoot) of the heat medium. It becomes possible to

In addition, as the locally heated heat medium circulates, the return temperature of the heat medium flowing into the second heat exchanger 16 also rises and exceeds the operating temperature (97 degrees) of the overheat switch 26. When the high-temperature heat medium flows into the first heat exchanger 15 through the second heat exchanger 16 over time with a small flow rate, the possibility of the overheat switch 26 operating increases, and the second heat exchange The risk of damage to the heat exchanger 16 and the first heat exchanger 15 also increases. Therefore, when the return temperature of the heat medium reaches the second predetermined temperature or higher before the return temperature reaches the operating temperature, the three-way valve 29 increases the opening of the branch passage 27 (hot water supply circuit). If the total flow rate of the heat medium flowing into the second heat exchanger 16 is secured, the possibility of the overheat switch 26 operating is reduced, and the risk of damage to the second heat exchanger 16 and the first heat exchanger 15 is reduced. can do.

Furthermore, by increasing the opening of the branch passage 27 (hot water supply circuit), the total flow rate of the circulating heat medium is secured, and from the viewpoint of quickly alleviating fluctuations in the temperature of the heat medium, the three-way valve 29 is operated for hot water supply. It is more advantageous to move to the state of However, as described above, when the temperature of the heat medium rises while the burner 3 is not burning during the heating operation, the flow of the heat medium is completely cut off at the heating terminal (floor heating 50). For example, it can occur not only in the case where two of the three floor heaters 50 a to 50 c close the switching valves 52 and the heat medium circulates in the remaining one floor heater 50 . In this case, if the three-way valve 29 is moved to the hot water supply operation, the heating medium cannot be distributed to the heating terminals. Therefore, by moving the three-way valve 29 not to the hot water supply operation state but to the intermediate state as in the present embodiment, the heat medium is circulated to the heating terminal and the heating operation is continued while the heat medium is supplied as described above. It is possible to quickly mitigate temperature fluctuations.

Although the heating and hot water supply apparatus 1 of the present embodiment has been described above, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the scope of the invention.

For example, in the above-described embodiment, the opening of the terminal-side return passage 22a (heating circuit) and the opening of the branch passage 27 (hot water supply circuit) are switched by the three-way valve 29, thereby adjusting the distribution ratio for distributing the common heat medium. was supposed to change. However, the means for changing the distribution ratio is not limited to the three-way valve 29, and a heating on/off valve for opening/closing (changing the degree of opening) the heating circuit and a hot water supply on/off valve for opening/closing (changing the degree of opening) the hot water supply circuit are provided. You can leave it. In this case, in the heating operation, the heating opening/closing valve is opened and the hot water supply opening/closing valve is closed. The hot water supply opening/closing valve may be opened when the temperature exceeds the temperature or when the return temperature of the heat medium reaches or exceeds the second predetermined temperature. However, if the three-way valve 29 is used as in the above-described embodiment, the opening of the heating circuit can be decreased in conjunction with increasing the opening of the hot water supply circuit.

Further, in the above-described embodiment, when the temperature of the heat medium rises with the burner 3 stopping combustion during the heating operation, the three-way valve 29 is moved from the heating operation state to the intermediate state, and the terminal side The degree of opening of the return passage 22a (heating circuit) and the degree of opening of the branch passage 27 (hot water supply circuit) are substantially the same. However, the position to which the three-way valve 29 is moved is not limited to the intermediate state as long as the degree of opening of the hot water supply circuit is increased more than in the heating operation state. For example, if the opening of the hot water supply circuit is made larger than the opening of the heating circuit, it is advantageous to secure the total flow rate of the circulating heat medium even if the flow rate of the heat medium is throttled on the heating terminal side. On the other hand, if the degree of opening of the hot water supply circuit is made smaller than the degree of opening of the heating circuit, it is advantageous for continuing the heating operation and suppressing a decrease in thermal efficiency.

In addition, the ratio between the opening of the heating circuit and the opening of the hot water supply circuit can be switched from a plurality of stages (for example, 7:3, 5:5, 3:7) by the three-way valve 29, and the forward temperature of the heat medium becomes a first predetermined temperature or higher, or the return temperature of the heating medium reaches a second predetermined temperature or higher, the degree of opening of the hot water supply circuit may be selected according to the temperature. The opening of the circuit may be increased.

Further, in the above-described embodiment, while only the heating operation is being performed (when the ratio of the opening of the heating circuit and the opening of the hot water supply circuit is 10:0), the flow rate of the heat medium is throttled on the heating terminal side, and the circulation It was assumed that the total flow rate of the heat transfer medium would decrease significantly. However, the present invention can also be applied to a simultaneous operation in which hot water supply operation is performed together with heating operation. For example, when the ratio of the opening of the heating circuit and the opening of the hot water supply circuit is 8:2 for simultaneous operation, if the flow rate of the heat medium is throttled on the heating terminal side, the total flow rate of the circulating heat medium increases. may decrease. Therefore, if the opening degree of the hot water supply circuit is increased based on the fact that the temperature of the heat medium rises even after the combustion in the burner 3 is stopped, the fluctuation of the temperature of the heat medium can be quickly alleviated. can.

Further, in the above-described embodiment, the three-way valve 29 is provided with the differential pressure valve 66 . However, the differential pressure valve 66 is not essential, and the present invention can be preferably applied even when the differential pressure valve 66 is not provided.

DESCRIPTION OF SYMBOLS 1... Heating water heater, 2... Housing, 3... Burner,
4 Combustion unit 5 Combustion fan 6 Junction part
7 air supply path 8 gas supply path 9 zero governor
11... spark plug, 12... flame rod, 13... check valve,
15... First heat exchanger, 16... Second heat exchanger, 17... Exhaust duct,
18... Exhaust port, 19... Air supply port, 21... Forward passage,
22... Return passage, 23... Circulation pump, 24... Return temperature sensor,
25... Forward temperature sensor, 26... Overheat switch,
27... branch passage, 28... hot water supply heat exchanger, 29... three-way valve,
30... Water supply passage, 31... Hot water outlet passage, 32... Water level sensor,
33...Water volume servo, 34...Water supply temperature sensor,
35... Hot water supply heat exchanger outlet temperature sensor, 36... Bypass passage,
37... Bypass servo, 38... Hot water temperature sensor, 40... Controller,
41...hot water supply remote control, 42...heating remote control, 50...floor heating,
51... Pipe, 52... Switching valve, 60... Valve chamber,
61... Hot water supply side valve body 62... Heating side valve body 63... Moving shaft
64... drive motor, 65... connection passage, 66... differential pressure valve,
67... Valve body, 68... Valve seat, 69... Valve closing spring.

Claims (3)

Using a common heat medium, a heating operation in which the heat medium is circulated through the heating terminal for heating, and a heating operation in which the heat medium is circulated through the hot water supply heat exchanger to heat the water supplied to the hot water supply heat exchanger. A heating and hot water supply apparatus capable of performing a hot water supply operation for generating hot water by heating by heat exchange with a medium,
heating means for heating the heat medium;
a circulation pump for sending the heat medium;
a temperature detecting means for detecting the temperature of the heat medium;
heating control means for controlling heating of the heating means according to the temperature of the heat medium;
It is possible to change the distribution ratio for distributing the common heat medium by switching the opening degrees of the heating circuit that circulates the heat medium to the heating terminal and the hot water supply circuit that circulates the heat medium to the hot water supply heat exchanger. distribution means and
Distribution control means for controlling switching of the distribution means,
When the hot water supply circuit is closed to stop the hot water supply operation, and the heating circuit is opened to stop the heating of the heating means during the execution of the heating operation, the temperature of the heat medium is equal to or higher than a predetermined temperature. Then, the distribution control means controls the distribution means so as to open the hot water supply circuit and increase the degree of opening. In the heating and hot water supply apparatus according to claim 1,
The distribution control means increases the degree of opening of the hot water supply circuit when the temperature of the heat medium flowing out from a portion where the heat medium is heated by the heating means reaches or exceeds a first predetermined temperature as the predetermined temperature. A heating and hot water supply apparatus characterized by controlling a distribution means. In the heating and hot water supply apparatus according to claim 1 or claim 2,
The distribution control means increases the degree of opening of the hot water supply circuit when the temperature of the heat medium flowing into a location where the heat medium is heated by the heating means reaches or exceeds a second predetermined temperature as the predetermined temperature. A heating and hot water supply apparatus characterized by controlling a distribution means.

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