JP2020180723A - Device for supplying mixture of hot water and water and cogeneration system - Google Patents

Abstract

To enable hot water having proper temperature to be supplied at re-supply of mixture of hot water and water, and to prevent hot water having high temperature exceeding a target temperature from being supplied.SOLUTION: A device for supplying mixture of hot water and water comprises: a first check valve provided at a hot-water side path; a second check valve provided at a water-side path; a mixing valve provided at a merging portion between the hot-water side path and the water-side path, mixing hot water from the hot-water side path and water from the water-side path at a changeable mixing ratio, and outputting the mixture to a path for mixture of hot water and water; and a control device. When the mixture of hot water and water is supplied, the control device sets a target mixing rate by performing feedback control so that temperature at the supply of mixture of hot water and water reaches a target temperature, and controls the mixing valve, and when the supply of mixture of hot water and water is stopped, the control device controls the mixing valve so that the mixing ratio immediately before the stop of the supply of mixture of hot water and water is maintained. Also, when the temperature at the supply of mixture of hot water and water is deviated from a proper state during the supply of mixture of hot water and water, the control device sets a target mixing rate so that the mixing valve is fully closed to a hot water side, and controls the mixing valve.SELECTED DRAWING: Figure 4

Description

The present invention relates to a hot water discharge device that mixes hot water and water to discharge hot water, and a cogeneration system including the same.

Conventionally, this type of hot water discharge device is provided at a water inlet and a hot water passage connected to a hot water storage tank, a bypass passage branched from the inlet and connected to the hot water passage, and a connection portion between the hot water passage and the bypass passage. A mixing valve that mixes hot water from the hot water outlet (path on the hot water side) and water from the bypass path (path on the water side) at a mixing ratio that can be controlled by a stepping motor and outputs it to the mixing path, and a bypass path (bypass path). The first check valve provided on the water side path), the second check valve provided on the downstream side (the hot water side path) from the branch portion between the water inlet and the bypass path, and the mixing valve. A control unit that performs control has been proposed (see, for example, Patent Document 1). When the water volume sensor detects the passage of water to the water inlet, the control unit sets the mixing ratio so that the temperature of the hot water after mixing the hot water becomes the set hot water supply temperature set by the user, and the set mixing ratio. The mixing valve (stepping motor) is controlled so as to be. The opening pressures of the first and second check valves are set so that the first check valve opens and the second check valve does not open when the flow rate is less than the detectable flow rate of the water amount sensor. Above the detectable flow rate, both the first and second check valves are set to open. As a result, when a small amount of hot water is supplied from which the water amount sensor cannot detect the passage of water, only the water that has passed from the water inlet passage to the bypass passage is discharged through the mixing valve, so that it is possible to prevent hot water from coming out. Further, when a water flow amount that can be detected by the water amount sensor flows, both the first and second check valves are opened, so that the control unit controls the mixing valve. At this time, since the position of the mixing valve is stopped at the standby position when the hot water supply is stopped, the undershoot in which the temperature of the hot water that comes out when the hot water is discharged again becomes lower than the set temperature is suppressed.

Japanese Unexamined Patent Publication No. 2003-42553

By the way, by maintaining the opening degree of the mixing valve at the opening degree immediately before the hot water discharge is stopped after the hot water discharge is stopped, it is possible to immediately supply hot water at an appropriate temperature even when the hot water is discharged again. However, there are manufacturing variations in the opening pressure of the check valve, and depending on the device, the check valve on the water side is easier to open than the check valve on the hot water side, and the check valve on the hot water side. Some may be easier to open than the check valve on the water side. For example, in the former case, when hot water is discharged in such a small amount that the check valve on the water side opens and the check valve on the hot water side does not open, the water is mixed so that the water discharge temperature (hot water temperature) of the mixing valve becomes the target temperature. As a result of controlling the valve, the opening degree of the mixing valve is widened to the hot water side. Then, when the hot water is discharged again after the hot water is stopped, if the hot water is discharged in such an amount that both the check valve on the water side and the check valve on the hot water side are opened, the opening of the mixing valve is opened immediately before the hot water is stopped. Since it is maintained at a certain temperature, hot water with a temperature higher than the set hot water supply temperature may be discharged.

A main object of the present invention is to provide a hot water discharge device and a cogeneration system that can discharge hot water having an appropriate temperature at the time of re-delivery and prevent hot water exceeding a target temperature from being discharged. To do.

The hot water discharge device and the cogeneration system of the present invention have adopted the following means in order to achieve the above-mentioned main object.

The hot water discharge device of the present invention
It is a hot water discharge device that mixes hot water and water to discharge hot water.
The first check valve provided on the hot water side route and
The second check valve provided on the water side path and
It is provided at the confluence of the hot water side path and the water side path, and the hot water from the hot water side path and the water from the water side path are mixed at a changeable mixing ratio to form a hot water outlet. A mixing valve that discharges hot water and
A temperature sensor that detects the hot water temperature, which is the temperature of the hot water discharged to the hot water passage, and
When the hot water is discharged, the target mixing ratio is set by feedback control so that the hot water temperature detected by the temperature sensor becomes the target temperature, and the mixing valve is controlled. When the hot water is stopped, immediately before the hot water is stopped. A control device that controls the mixing valve so that the mixing ratio of the above is maintained for a predetermined time.
With
When the hot water temperature detected by the temperature sensor deviates from the proper state while the hot water is being discharged, the control device sets a target mixing ratio so that the mixing valve is fully closed to the hot water side until the hot water is stopped. Set to control the mixing valve,
The gist is that.

In the hot water discharge device of the present invention, the first check valve provided in the hot water side path, the second check valve provided in the water side path, and the confluence of the hot water side path and the water side path. The unit is provided with a mixing valve that mixes hot water from the hot water side path and water from the water side path at a changeable mixing ratio and outputs the hot water to the hot water outlet, and a control device. The control device controls the mixing valve by setting the target mixing ratio by feedback control so that the hot water discharge temperature becomes the target temperature when the hot water is discharged, and when the hot water discharge is stopped, the mixing ratio immediately before the hot water discharge is stopped is set. Control the mixing valve so that it is maintained. As a result, hot water at an appropriate temperature can be immediately supplied when the hot water is re-drained after the hot water is stopped. In addition, the control device controls the mixing valve by setting the target mixing ratio so that the mixing valve is fully closed to the hot water side until the hot water is stopped when the hot water temperature deviates from the proper state while the hot water is being discharged. To do. Here, since the valve opening pressures of the first and second check valves vary in manufacturing, the first check valve is easier to open than the second check valve depending on the device, and the first check valve is stopped when a small amount of hot water is discharged. There may be a case where only the valve is opened and only hot water is discharged, and a case where the second check valve is easier to open than the first check valve and only the second check valve is opened and only water is discharged when a small amount of hot water is discharged. Therefore, in the present invention, when the hot water discharge temperature deviates from the proper state, the mixing valve is fully closed to the hot water side until the hot water discharge is stopped, so that the target temperature is exceeded regardless of the variation in the set pressure of the check valve. It is possible to prevent hot water from being discharged and ensure the safety of the user.

The hot water discharge device of the present invention includes a bypass path that branches from the water side path, bypasses the mixing valve, and is connected to the hot water discharge path, and an on-off valve provided in the bypass path. When the hot water outlet temperature detected by the temperature sensor is equal to or higher than a predetermined upper limit temperature, the control device sets the on-off valve so that water from the water side path is output to the hot water discharge path via the bypass path. The mixing valve may be controlled by setting a target mixing ratio so that the mixing valve is fully closed on the hot water side at the same time as opening the valve. For example, in a device in which the first check valve is easier to open than the second check valve due to manufacturing variations, when only the first check valve is opened and only the hot water is discharged when a small amount of hot water is discharged, a bypass path is immediately provided. Since water is supplied from the hot water channel to the hot water channel, the safety of the user can be ensured. At the same time, by fully closing the mixing valve to the hot water side, hot water is discharged because the hot water is started with the mixing valve fully closed to the hot water side when the hot water is re-drained after the hot water is stopped. It can be prevented more reliably.

Further, in the hot water discharge device of the present invention, the control device targets mixing so that the mixing valve is fully closed to the hot water side when the hot water temperature detected by the temperature sensor or the opening degree of the mixing valve is hunted. The ratio may be set to control the mixing valve. Since the mixing valve is controlled by feedback control so that the hot water temperature becomes the target temperature, when the opening degree of the mixing valve changes alternately between the hot water side and the water side by the feedback control when a small amount of hot water is discharged, the first hot water side first. The check valve and the second check valve on the water side alternately open and close, and the hot water temperature hunts. At this time, if the hot water is stopped while the mixing valve is open to the hot water side, hot water may be discharged because the hot water is started with the mixing valve open to the hot water side when the hot water is discharged again. There is. Therefore, when the hot water temperature or the opening of the mixing valve is hunted, the mixing valve is fully closed to the hot water side, so that the mixing valve is fully closed to the hot water side when the hot water is discharged again after the hot water is stopped. Since the hot water is started at, it is possible to more reliably prevent the hot water from being discharged.

Further, the hot water discharge device of the present invention includes a second temperature sensor that detects the temperature of water flowing through the path on the water side, and the control device has the mixing valve fully opened on the hot water side and the temperature sensor. When the deviation between the detected hot water temperature and the water temperature detected by the second temperature sensor is less than a predetermined value, the target mixing ratio is set so that the mixing valve is fully closed on the hot water side, and the mixing is performed. It may control the valve. In a device in which the second check valve is easier to open than the first check valve due to manufacturing variations, the mixing valve will be used when only the second check valve is opened and only water is discharged when a small amount of hot water is discharged. , The hot water temperature is controlled to be fully open on the hot water side so that it becomes the target temperature. When the hot water is stopped in this state and the hot water is re-drained to the extent that both the first and second check valves are opened, the hot water is started with the mixing valve fully open to the hot water side, so that the temperature is high. There is a risk that the hot water will be discharged. Therefore, in the present invention, when the mixing valve is fully opened to the hot water side and the deviation between the hot water discharge temperature and the target temperature is less than a predetermined value, the mixing valve is fully closed to the hot water side so that the hot water can be discharged again after the hot water is stopped. At that time, since the hot water is started in a state where the mixing valve is fully closed on the hot water side, it is possible to more reliably prevent the hot water from being discharged.

The cogeneration system of the present invention
With any of the hot water discharge devices of each aspect of the present invention described above,
Power generator and
A hot water storage tank that can store hot water using the heat generated by the power generation of the power generation device and output the stored hot water to the hot water channel.
A housing for accommodating the hot water discharge device, the power generation device, and the hot water storage tank,
The gist is to prepare.

Since the cogeneration system of the present invention is provided with the hot water discharge device according to any one of the above-described aspects of the present invention, the same effect as that of the hot water discharge device of the present invention, for example, hot water at an appropriate temperature can be discharged at the time of re-water discharge. In addition to this, it is possible to achieve the effect of suppressing the supply of high-temperature hot water at the time of re-draining after a small amount of hot water is discharged.

It is a block diagram which shows the outline of the structure of the cogeneration system 10 of this embodiment. It is explanatory drawing which shows the relationship between each valve opening pressure C, H of the 1st and 2nd check valves 32, 33, a hot water discharge amount, and a hot water discharge temperature. It is a flowchart which shows an example of a hot water discharge control routine. It is a flowchart which shows an example of the hot water temperature monitoring process. It is explanatory drawing which shows the state of time change of the opening degree θ of the mixing valve 31 and the state of a bypass valve 34 when a hot water discharge temperature high temperature abnormality occurs by hot water discharge. It is explanatory drawing which shows the state of time change of the opening degree θ of the mixing valve 31 and the state of a bypass valve 34 when hunting occurs by repeating hot water tapping and tap water tapping. It is explanatory drawing which shows the state of time change of the opening degree θ of the mixing valve 31 and the state of a bypass valve 34 in the case of water discharge.

A mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an outline of the configuration of the cogeneration system 10 of the present embodiment. The cogeneration system 10 is installed in a house, for example, and as shown in the figure, the power generation module 12, the exhaust heat recovery system 20 that recovers the exhaust heat generated by the power generation of the power generation module 12 as hot water, and the exhaust heat. It is provided with a hot water discharge device 30 that mixes hot water recovered by the heat recovery system 20 with water from a water supply source (not shown) and discharges hot water. In the present embodiment, the power generation module 12, the exhaust heat recovery system 20, and the hot water discharge device 30 are housed in a single housing 11.

The power generation module 12 is configured to include, for example, a solid oxide fuel cell, an evaporator, a reformer, a module case for accommodating these, and the like, and is a reformed gas generated by reforming the raw fuel gas ( It is configured as a fuel cell module that generates power from hydrogen gas) and oxidizing agent gas. The power generation module 12 may be configured by a combination of a prime mover (gas engine, gas turbine, etc.) and a generator that generates electricity by power from the prime mover.

The exhaust heat recovery system 20 comprises a hot water storage tank 21 that stores hot water so as to form a temperature stratification, and combustion exhaust gas and hot water stored water that are connected to the hot water storage tank 21 via a circulation pipe La and discharged from the power generation module 12. It includes a heat exchanger 22 for heat exchange and a circulation pump 23 provided in the circulation pipe La. In the exhaust heat recovery system 20, by operating the circulation pump 23, the hot water stored in the hot water storage tank 21 is drawn from the lower part of the hot water storage tank 21 and sent to the heat exchanger 22, and the fuel exhaust gas in the heat exchanger 22. The hot water that has been heated by heat exchange with is returned to the upper part of the hot water storage tank 21.

A water supply pipe L1 to which a water supply source (not shown) is connected and a drainage pipe L11 are connected to the lower part of the hot water storage tank 21. The water supply pipe L1 is provided with a strainer, a check valve, a pressure reducing valve, etc. (not shown), and water from the water supply source is supplied into the hot water storage tank 21 via the water supply pipe L1. Further, the drainage pipe L11 is provided with a drainage valve V11, and by opening the drainage valve V11, the hot water in the hot water storage tank 21 can be discharged to the outside.

Further, a hot water pipe L2 is connected to the upper part of the hot water storage tank 21, and by supplying water from the lower part of the hot water storage tank 21 via the water supply pipe L1, the hot water pipe L2 is supplied from the upper part of the hot water storage tank 21. Hot water can be taken out.

The hot water outlet device 30 is provided at the confluence of the hot water pipe L2, the water pipe L3 branched from the water supply pipe L1, and the hot water pipe L22 and the water pipe L3, and provides hot water from the hot water pipe L2 and water from the water pipe L3. Bypasses the mixing valve 31 that mixes and discharges to the hot water outlet pipe L4, the first check valve 32 provided in the hot water pipe L2, the second check valve 33 provided in the water pipe L3, and the mixing valve 31. A bypass pipe L5 connected to the water pipe L3 and the hot water outlet pipe L4, a bypass valve 34 (open / close valve) provided in the bypass pipe L5, and a control device 40 for controlling the entire device are provided. The hot water discharged from the hot water outlet pipe L4 is sent to the home via an auxiliary heat source provided in a hot water supply device (not shown).

The mixing valve 31 adjusts the opening degree θ to the hot water side or the water side by a stepping motor, so that the ratio of the hot water discharge amount to the hot water discharge amount is, for example, 0% to 65%, in other words, the discharge of the mixed hot water. It is configured so that the ratio of the discharge amount of water to the amount can be adjusted in the range of, for example, 100% to 45%.

The first and second check valves 32 and 33 are configured to close by the load of the built-in spring and open when a pressure (pressure equal to or higher than the valve opening pressure) that overcomes the spring load is applied. .. In the present embodiment, the first check valve 32 and the second check valve 33 have the same valve opening pressure H of the first check valve 32 and the valve opening pressure C of the second check valve 33. , The same specifications are used. However, since there are manufacturing variations in the spring load, as shown in FIG. 2, the valve opening pressure H of the first check valve 32 is lower than the valve opening pressure C of the second check valve 33, which is a small amount. When hot water is discharged, the system (see broken line in the figure) that makes it easier for hot water to come out than the specified system (see solid line in the figure) and the valve opening pressure H of the first check valve 32 are the second check valve 33. A system (see the alternate long and short dash line in the figure) that is higher than the valve opening pressure C and more easily discharges water than the specified system (see the solid line in the figure) may occur when a small amount of hot water is discharged.

The control device 40 is configured as a microprocessor centered on the CPU 41. In addition to the CPU 41, a ROM 42 for storing a processing program, a RAM 43 for temporarily storing data, a timer 44 for timing, and input / output It has a port. The control device 40 is provided with a water supply temperature Tin from a temperature sensor 51 that is provided in the water pipe L3 and detects the temperature of water passing through the water pipe L3, and a temperature of the mixed hot water that is provided in the hot water pipe L4 and passes through the hot water pipe L4. The hot water temperature Tout from the temperature sensor 52 to be detected is input via the input port. Further, from the control device 40, a drive signal to the mixing valve 31 (stepping motor), a drive signal to the bypass valve 34, and the like are output via the output port. The control device 40 also functions as a control device for the cogeneration system 10. Therefore, a signal from a sensor (not shown) for detecting the operating state of the power generation module 12 is input to the control device 40 via an input port, and the control device 40 sends a control signal to the power generation module 12 and a circulation pump 23. Control signal is output via the output port.

Next, the operation of the cogeneration system 10 thus configured, particularly the hot water discharge operation by the hot water discharge device 30, will be described. FIG. 3 is a flowchart showing an example of a hot water discharge control routine executed by the CPU 41 of the control device 40.

When the hot water discharge control routine is executed, the CPU 41 of the control device 40 first determines whether or not the hot water is being discharged (step S100). This determination can be made by, for example, whether or not water flow is detected by a flow rate sensor (not shown) provided in a water supply pipe L1, a hot water outlet pipe L4, a pipe connected to the hot water outlet pipe L4, or the like. When it is determined that the hot water is being discharged, the set temperature Tset set by the user by operating the remote control device (not shown), the water supply temperature Tin from the temperature sensor 51, and the hot water discharge temperature Tout from the temperature sensor 52 are input. (Step S110). Subsequently, the target temperature Tout * is set based on the input set temperature Tset and the water supply temperature Tin (step S120). The target temperature Tout * is set by obtaining the relationship between the set temperature Tset, the water supply temperature Tin, and the target temperature Tout * in advance and storing it in the ROM 42 as a map. When the set temperature Tset and the water supply temperature Tin are given, the map is set. It was decided to carry out by deriving the corresponding target temperature Tout * from. The target temperature Tout * is set so as to be higher as the set temperature Tset is higher and higher as the water supply temperature Tin is higher.

Then, the target opening degree θ * is set by the following equation (1) based on the deviation between the hot water discharge temperature Tout and the target temperature Tout * (step S130), and the opening degree θ of the mixing valve 31 becomes the target opening degree θ *. The stepping motor is controlled (step S140). Equation (1) is a relational expression in feedback control for matching the hot water temperature Tout with the target temperature Tout *, where "kp" indicates the gain in the proportional term and "ki" indicates the gain in the integral term.

θ * = kp ・ (Tout-Tout *) + ki ・ ∫ (Tout-Tout *) dt… (1)

Next, a hot water temperature monitoring process for monitoring the hot water temperature Tout is performed (step S150). The hot water temperature monitoring process will be described later. After executing the hot water temperature monitoring process, or when it is determined in step S100 that the hot water is not being discharged, it is determined whether or not the hot water is stopped (step S160). If it is determined that the hot water supply is not stopped, the process returns to step S100. On the other hand, if it is determined that the hot water supply is stopped, the target opening degree θ * this time is set to the target opening degree (previous time θ *) set in this routine last time (step S170), and the opening degree θ of the mixing valve 31 is changed. The stepping motor is controlled so that the target opening degree θ * is obtained (step S180). As a result, the opening degree θ of the mixing valve 31 is maintained at the opening degree immediately before the hot water discharge is stopped. Therefore, at the time of re-delivery, the hot water temperature Tout does not cause an undershoot that is much lower than the target temperature Tout * or an overshoot that the hot water temperature Tout greatly exceeds the target temperature Tout * with respect to the target temperature Tout *. Hot water can be discharged. Then, it is determined whether or not a predetermined time (several minutes or tens of minutes) has elapsed since the hot water was stopped (step S190). If it is determined that the predetermined time has not elapsed, the process returns to step S100. On the other hand, when it is determined that the predetermined time has elapsed, the target opening degree θ * is set to the origin θ0 (the opening degree θ on the hot water side is 0 degree) so that the mixing valve 31 is fully closed on the hot water side (step S200). The stepping motor is controlled so that the opening degree θ of the mixing valve 31 becomes the target opening degree θ * (step S210), and this routine ends.

Next, the hot water temperature monitoring process will be described. FIG. 4 is a flowchart showing an example of the hot water temperature monitoring process executed by the CPU 41 of the control device 40. In the hot water temperature monitoring process, the CPU 41 first determines whether or not the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold value Tlim (step S300). This determination determines an abnormal rise in the hot water temperature Tout. In this state, the valve opening pressure H of the first check valve 32 on the hot water side and the valve opening pressure C of the second check valve 33 on the water side are equal to each other, or the valve opening pressure of the first check valve 32 on the hot water side. H is lower than the valve opening pressure C of the second check valve 33 on the water side, and can occur in a system in which hot water is likely to come out when a small amount of hot water is discharged (a system having hot water discharge characteristics shown by a solid line or a broken line in FIG. 2). When it is determined that the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold value Tlim, the bypass valve 34 is opened (step S310). As a result, the water from the water supply source can be directly supplied to the hot water outlet pipe L4, and the hot water outlet temperature Tout can be quickly lowered. Subsequently, the target opening degree θ * is set to the origin θ0 so that the mixing valve 31 is fully closed on the hot water side (step S320), and the stepping motor is set so that the opening degree θ of the mixing valve 31 becomes the target opening degree θ *. Control (step S330). Then, the target opening degree θ is set to the previous target opening degree so that the opening degree θ of the mixing valve 31 is maintained at the origin θ0 until the hot water supply is stopped, and the stepping motor is controlled by the target opening degree θ ( Steps S330 to S350), this process is terminated. When the hot water is stopped, it is determined that the hot water is stopped in step S160 of the hot water control routine of FIG. 3, and the opening degree θ of the mixing valve 31 is the origin until it is determined in step S100 that the hot water is being discharged. It is maintained in the state of θ0.

FIG. 5 is an explanatory diagram showing a state of time change of the opening degree θ of the mixing valve 31 and the state of the bypass valve 34 when a hot water discharge temperature high temperature abnormality occurs due to hot water discharge. As shown in the figure, when the amount of hot water Q exceeds the minimum amount of working water of the flow rate sensor and hot water is detected (time t11), the opening degree of the mixing valve 31 is controlled by feedback so that the hot water temperature Tout becomes the target temperature Tout *. When θ is controlled and the amount of hot water Q falls below the minimum amount of working water of the flow sensor and the stop of hot water is detected (time t12), the opening of the mixing valve 31 is maintained at the opening immediately before the stop of hot water. As a result, at the time of re-delivery, the hot water temperature Tout does not cause an undershoot that is much lower than the target temperature Tout * or an overshoot that the hot water temperature Tout greatly exceeds the target temperature Tout * with respect to the target temperature Tout *. It is possible to discharge hot water at an appropriate temperature. However, in a system in which hot water is likely to come out when a small amount of hot water is discharged, if the hot water is re-drained with a small amount such that the amount of hot water Q slightly exceeds the minimum working water amount of the flow sensor (time t13), the second check valve on the water side In 33, the first check valve 32 on the hot water side is opened while the valve is closed, and only hot water is discharged. Therefore, when the hot water outlet temperature Tout becomes equal to or higher than the high temperature abnormality determination threshold value Tlim, the bypass valve 34 is opened and the opening degree θ of the mixing valve 31 is returned to the origin θ0 (time t14, t15) until the hot water discharge is stopped. In this way, when the hot water discharged to the hot water outlet pipe L4 reaches the high temperature abnormality determination threshold Trim, the bypass valve 34 is opened and the water is directly supplied to the hot water outlet pipe L4 via the bypass pipe L5. By setting the opening degree θ of the mixing valve 31 to the origin θ0 (the opening degree θ on the hot water side is 0 degrees), it is possible to eliminate the high temperature abnormality and prevent the high temperature abnormality from being repeated when the hot water is discharged again. The safety of the user can be ensured.

In step S300, if it is determined that the hot water temperature Tout is not equal to or higher than the high temperature abnormality determination threshold Tlim and is less than the high temperature abnormality determination threshold Tlim, it is determined whether or not hunting occurs in which the hot water temperature Tout repeatedly rises and falls. (Step S360). In the determination of hunting, for example, it is determined whether or not a state in which the hot water temperature Tout rises by a predetermined temperature or more within a predetermined time and a state in which the hot water temperature Tout falls by a predetermined temperature or more within a predetermined time occur alternately a predetermined number of times. It is done by doing. The state in which the opening degree θ of the mixing valve 31 increases by a predetermined amount or more on the hot water side within a predetermined time and the state in which the opening degree θ of the mixing valve 31 decreases by a predetermined amount or more on the hot water side within a predetermined time alternate. It may be performed by determining whether or not it has occurred a predetermined number of times, or it may be performed by a combination of both determinations. When it is determined that hunting has occurred at the hot water temperature Tout, the angle obtained by adding the predetermined value α to the origin θ0 is set to the target opening degree θ * (step S370), and the opening degree θ of the mixing valve 31 is the target opening degree θ. The stepping motor is controlled so as to be * (step S330). Here, the predetermined value α is set as a value within a dead zone (play) in which hot water is hardly discharged from the mixing valve 31 even if the opening degree θ of the mixing valve 31 is increased from the origin θ0 to the hot water side. .. Then, the target opening degree θ is set to the previous target opening degree so that the opening degree θ of the mixing valve 31 is maintained at the origin θ0 until the hot water supply is stopped, and the stepping motor is controlled by the target opening degree θ ( Steps S330 to S350), this process is terminated.

FIG. 6 is an explanatory diagram showing a state of time change of the opening degree θ of the mixing valve 31 and the state of the bypass valve 34 when hunting occurs due to the repetition of hot water and hot water. As shown in the figure, when the amount of hot water Q exceeds the minimum amount of working water of the flow rate sensor and hot water is detected (time t21), the opening degree of the mixing valve 31 is controlled by feedback so that the hot water temperature Tout becomes the target temperature Tout *. When θ is controlled and the amount of hot water Q falls below the minimum amount of working water of the flow sensor and the stop of hot water is detected (time t22), the opening of the mixing valve 31 is maintained at the opening immediately before the stop of hot water. After that, when the hot water discharge amount Q is re-delivered in a small amount slightly exceeding the minimum working water amount of the flow rate sensor (time t23), the mixing valve 31 is controlled by feedback control so that the hot water discharge temperature Tout becomes the target temperature Tout *. Therefore, when the opening degree of the mixing valve 31 changes alternately between the hot water side and the water side by the feedback control, the first check valve 32 and the second check valve 33 alternately repeat opening and closing, and the hot water temperature Tout. Hunts. At this time, if the hot water is stopped while the mixing valve 31 is open to the hot water side, the hot water is discharged because the hot water is started with the mixing valve 31 open to the hot water side when the hot water is discharged again. There is a risk of Therefore, in the present embodiment, when hunting occurs at the hot water discharge temperature Tout, the opening degree θ of the mixing valve 31 is returned to the opening degree obtained by adding a predetermined value α determined within the range of the dead zone to the origin θ0 until the hot water discharge is stopped. (Time t24, t25). As a result, it is possible to prevent hot water from being discharged when the hot water is discharged again. Here, in the present embodiment, when hunting occurs at the hot water discharge temperature Tout, the opening degree θ of the mixing valve 31 is set to an opening degree that is open to the hot water side from the origin θ0 within the range of the dead zone, so that the hot water is discharged again. When changing the opening degree θ of the mixing valve 31 to the target opening degree θ *, the time required to reach the target opening degree θ * can be shortened as compared with the case where the opening degree θ is changed from the origin θ0. However, as described above, when the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold value Tlim, the opening degree θ of the mixing valve 31 is returned to the origin θ0 in consideration of user safety.

In step S360, if it is determined that hunting does not occur in the hot water temperature Tout, whether or not the temperature difference obtained by subtracting the water supply temperature Tin from the hot water temperature Tout is less than the predetermined temperature difference Tref (step S380), the present of the mixing valve 31 It is determined whether or not the opening degree θ of the above is fully open to the hot water side (in the present embodiment, the mixing ratio of hot water and water is 65%: 35%) (step S390). Here, the current opening degree θ can be detected by counting the number of steps of the stepping motor. The determination in step S390 may be performed using the target opening degree θ * instead of the opening degree θ. In the determination of steps S380 and S390, even if the opening degree θ of the mixing valve 31 is opened to the hot water side, the first check valve 32 on the hot water side does not open, so that the second check valve 32 on the water side is not opened from the mixing valve 31. It is for determining a state in which only water is discharged through the check valve 33. This state can occur in a system in which the valve opening pressure H of the first check valve 32 on the hot water side is higher than the valve opening pressure C of the second check valve 33 on the water side and water is likely to come out when a small amount of hot water is discharged. When it is determined that the temperature difference obtained by subtracting the water supply temperature Tin from the hot water outlet temperature Tout is less than the predetermined temperature difference Tref and the current opening degree θ of the mixing valve 31 is fully open to the hot water side, a predetermined value is set at the origin θ0. The angle to which α is added is set to the target opening degree θ * (step S370), and the stepping motor is controlled so that the opening degree θ of the mixing valve 31 becomes the target opening degree θ * (step S330). Then, the target opening degree θ is set to the previous target opening degree so that the opening degree θ of the mixing valve 31 is maintained at the origin θ0 until the hot water supply is stopped, and the stepping motor is controlled by the target opening degree θ ( Steps S330 to S350), this process is terminated.

FIG. 7 is an explanatory diagram showing a state of time change of the opening degree θ of the mixing valve 31 and the state of the bypass valve 34 when the hot water is discharged. As shown in the figure, when the amount of hot water Q exceeds the minimum amount of working water of the flow rate sensor and hot water is detected (time t31), the opening degree of the mixing valve 31 is controlled by feedback so that the hot water temperature Tout becomes the target temperature Tout *. When θ is controlled and the amount of hot water Q falls below the minimum amount of working water of the flow sensor and the stop of hot water is detected (time t32), the opening of the mixing valve 31 is maintained at the opening immediately before the stop of hot water. After that, when the hot water is re-drained with a small amount such that the amount of hot water Q slightly exceeds the minimum amount of working water of the flow sensor (time t33), the first check valve on the hot water side is used in a system in which water tends to come out when a small amount of hot water is discharged. Only the second check valve 33 on the water side opens while the valve 32 is closed, and the hot water is discharged. In this case, the mixing valve 31 is fully opened to the hot water side so that the hot water temperature Tout becomes the target temperature Tout *. Then, in this state, when the hot water is stopped and then the hot water is re-drained, the hot water is started with the opening degree θ of the mixing valve 31 fully open to the hot water side, so that the hot water is discharged. There is a risk of Therefore, in the present embodiment, when there is almost no temperature difference between the hot water outlet temperature Tout and the water supply temperature Tin and the opening degree θ of the mixing valve 31 is fully open to the hot water side, the opening degree of the mixing valve 31 is opened until the hot water discharge is stopped. The θ is returned to the opening degree obtained by adding the predetermined value α determined within the range of the dead zone to the origin θ0 (time t34, t35). As a result, it is possible to prevent hot water from being discharged when the hot water is discharged again.

In step S380, it is determined that the temperature difference obtained by subtracting the water supply temperature Tin from the hot water temperature Tout is equal to or greater than the predetermined temperature difference Tref, or the target opening degree θ * currently set in step S390 is not fully opened on the hot water side. If it is determined, this process is terminated as it is.

In the hot water discharge device 30 of the present embodiment described above, the control device 40 sets the target opening degree θ * by feedback control so that the hot water discharge temperature Tout becomes the target temperature Tout * when the hot water is discharged, and sets the mixing valve 31. When the hot water is stopped, the mixing valve 31 is controlled so as to be maintained at the target opening degree θ * immediately before the hot water is stopped. As a result, it is possible to immediately supply hot water at an appropriate temperature without causing undershoot or overshoot at the time of re-watering after the hot water is stopped. Further, the control device 40 sets the target opening degree θ * so that the mixing valve 31 is fully closed on the hot water side when the hot water temperature Tout deviates from the proper state while the hot water is being discharged, and sets the mixing valve 31. Control. As a result, it is possible to prevent hot water having a temperature exceeding the target temperature Tout * from being discharged, and to ensure the safety of the user.

Further, in the hot water discharge device 30 of the present embodiment, the control device 40 directly supplies the water of the water supply pipe L1 to the hot water discharge pipe L4 via the bypass pipe L5 when the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold Tlim. The bypass valve 34 is opened and the target opening degree θ * is set so that the mixing valve 31 is fully closed on the hot water side to control the mixing valve 31. As a result, due to the variation in the valve opening pressures H and C of the first and second check valves 32 and 33, when only the first check valve 32 is opened and only the hot water is discharged when a small amount of hot water is discharged, immediately. Since water is supplied from the bypass pipe L5 to the hot water pipe L4, the safety of the user can be ensured. At the same time, by fully closing the mixing valve 31 to the hot water side, hot water can be discharged because the hot water is started in a state where the mixing valve 31 is fully closed to the hot water side when the hot water is discharged again after the hot water is stopped. It is possible to prevent the hot water from being discharged more reliably.

Further, in the hot water discharge device 30 of the present embodiment, the control device 40 sets the target opening degree θ * so that the mixing valve 31 is fully closed on the hot water side when the hot water temperature Tout is hunted, and sets the mixing valve 31. Control. As a result, when the hot water is re-drained after the hot water is stopped, the hot water is started with the mixing valve 31 fully closed on the hot water side, so that it is possible to more reliably prevent the hot water from being discharged. ..

Further, in the hot water discharge device 30 of the present embodiment, the control device 40 is a mixing valve when the mixing valve 31 is fully opened to the hot water side and the deviation between the hot water temperature Tout and the water supply temperature Tin is less than the predetermined temperature difference Tref. The mixing valve 31 is controlled by setting the target opening degree θ * so that 31 is fully closed on the hot water side. As a result, when the hot water is re-drained after the hot water is stopped, the hot water is started with the mixing valve 31 fully closed on the hot water side, so that it is possible to more reliably prevent the hot water from being discharged. ..

In the above-described embodiment, in the hot water temperature monitoring process, when the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold Tlim, when the hot water temperature Tout is hunting, the deviation between the hot water temperature Tout and the water supply temperature Tin is a predetermined temperature. When any of the conditions when the difference is less than Tref and the opening degree θ of the mixing valve 31 is fully open to the hot water side is satisfied, the opening degree θ of the mixing valve 31 is fully closed to the hot water side. Any one or two of the three conditions may be omitted.

In the above-described embodiment, when the hot water temperature Tout is equal to or higher than the high temperature abnormality determination threshold value Tlim, the opening degree θ of the mixing valve 31 is returned to the origin θ0, but the opening degree θ of the mixing valve 31 is insensitive to the origin θ0. It may be returned to the opening degree to which the predetermined value α defined within the range of is added.

Further, in the above-described embodiment, when the hot water temperature Tout is hunting, the deviation between the hot water temperature Tout and the water supply temperature Tin is less than the predetermined temperature difference Tref, and the opening degree θ of the mixing valve 31 is fully open to the hot water side. Occasionally, the opening degree θ of the mixing valve 31 is returned to the opening degree by adding a predetermined value α determined within the range of the dead zone to the origin θ0, but the opening degree θ of the mixing valve 31 may be returned to the origin θ0. Good.

In the above-described embodiment, the bypass pipe L5 is provided so as to connect the water pipe L3 and the hot water outlet pipe L4, but may be provided so as to connect the water supply pipe L1 and the hot water outlet pipe L4.

In the above-described embodiment, the first check valve 32 is provided in the hot water pipe L2, but it may be provided between the branch point of the water supply pipe L1 with the water pipe L3 and the hot water storage tank 21.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the first check valve 32 corresponds to the "first check valve", the second check valve 33 corresponds to the "second check valve", and the mixing valve 31 corresponds to the "mixing valve". The temperature sensor 52 corresponds to the "temperature sensor", and the control device 40 corresponds to the "control device". Further, the bypass pipe L5 corresponds to the "bypass path", and the bypass valve 34 corresponds to the "open / close valve". Further, the temperature sensor 51 corresponds to the "second temperature sensor". Further, the power generation module 12 corresponds to the "power generation device", the hot water storage tank 21 corresponds to the "hot water storage tank", and the housing 11 corresponds to the "housing".

Regarding the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for the embodiment to solve the problem is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the embodiment is the invention described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above using the embodiments, the present invention is not limited to these embodiments, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of hot water discharge devices and cogeneration systems.

10 Cogeneration system, 11 chassis, 12 power generation module, 20 exhaust heat recovery system, 21 hot water storage tank, 22 heat exchanger, 23 circulation pump, 30 hot water outlet, 31 mixing valve, 32 1st check valve, 33 2nd Check valve, 34 bypass valve, 40 control device, 41 CPU, 42 ROM, 43 RAM, 44 timer, 51, 52 temperature sensor, L1 water supply pipe, L2 hot water pipe, L3 water pipe, L4 hot water pipe, L11 drain pipe, V11 drain valve.

Claims (5)

It is a hot water discharge device that mixes hot water and water to discharge hot water.
The first check valve provided on the hot water side route and
The second check valve provided on the water side path and
It is provided at the confluence of the hot water side path and the water side path, and the hot water from the hot water side path and the water from the water side path are mixed at a changeable mixing ratio to form a hot water outlet. A mixing valve that discharges hot water and
A temperature sensor that detects the hot water temperature, which is the temperature of the hot water discharged to the hot water passage, and
When the hot water is discharged, the target mixing ratio is set by feedback control so that the hot water temperature detected by the temperature sensor becomes the target temperature, and the mixing valve is controlled. When the hot water is stopped, immediately before the hot water is stopped. A control device that controls the mixing valve so that the mixing ratio of the above is maintained for a predetermined time.
With
When the hot water temperature detected by the temperature sensor deviates from the proper state while the hot water is being discharged, the control device sets a target mixing ratio so that the mixing valve is fully closed to the hot water side until the hot water is stopped. Set to control the mixing valve,
Hot water supply device. The hot water discharge device according to claim 1.
A bypass path that branches off from the water-side path, bypasses the mixing valve, and is connected to the hot water outlet.
An on-off valve provided in the bypass path and
With
The control device has the on-off valve so that when the hot water outlet temperature detected by the temperature sensor is equal to or higher than a predetermined upper limit temperature, water from the water side path is output to the hot water discharge path via the bypass path. The target mixing ratio is set so that the mixing valve is fully closed on the hot water side while the valve is opened to control the mixing valve.
Hot water supply device. The hot water discharge device according to claim 1 or 2.
The control device sets a target mixing ratio so that the mixing valve is fully closed to the hot water side when the hot water discharge temperature detected by the temperature sensor or the opening degree of the mixing valve hunts, and the mixing valve is operated. Control,
Hot water supply device. The hot water discharge device according to any one of claims 1 to 3.
A second temperature sensor for detecting the temperature of water flowing through the path on the water side is provided.
In the control device, when the mixing valve is fully opened to the hot water side and the deviation between the hot water discharge temperature detected by the temperature sensor and the water temperature detected by the second temperature sensor is less than a predetermined value. The mixing valve is controlled by setting a target mixing ratio so that the mixing valve is fully closed on the hot water side.
Hot water supply device. The hot water discharge device according to any one of claims 1 to 4.
Power generator and
A hot water storage tank that can store hot water using the heat generated by the power generation of the power generation device and output the stored hot water to the hot water channel.
A housing for accommodating the hot water discharge device, the power generation device, and the hot water storage tank,
A cogeneration system equipped with.