JP2009174773A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system capable of preventing high temperature tapping, and capable of securing safety. <P>SOLUTION: The cogeneration system 100 is connected to a hot water tap 66b being a hot water using portion 66 and a bathtub 66a of a bathroom, and it is equipped with a hot water storage tank 18, a power generating unit 24, and a mixing unit 44. The mixing unit 44 connects a hot water supply path 48 and a water supply path 4, and it is equipped with a mixing path 40 mixing tap water supplied from a water pipe 2 with hot water supplied from the hot water storage tank 18, and a mixer 14 mixing the hot water and the tap water. If stopping of hot water supply is determined by a hot water supply amount sensor 12, a mixing ratio of the mixer 14 is maintained a predetermined time. After passage of the predetermined time, a tank solenoid valve 36 is closed to cut off a tank hot water supply path 34 in an upstream side of a connection part 42 of the hot water supply path 48 and the mixing path 44. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cogeneration system capable of heating water with generated heat generated by a power generation unit, storing the heated hot water, and supplying hot water using the stored hot water. In particular, the present invention relates to a cogeneration system that mixes hot water and cold water stored in hot water and supplies them to hot water use points (hot water supply, hot water bathing, etc.).

  A cogeneration system that stores hot water heated by generated heat and supplies it is known. Hot water heated by the generated heat is stored in a hot water storage tank. If hot water that is hotter than the hot water temperature (hot water set temperature) required at the location where hot water is used during hot water operation is stored in the hot water storage tank, the required temperature is obtained by mixing the hot water and cold water delivered from the hot water storage tank with the mixing means. Cool and supply hot water. Less heat is required than when cold water is heated with a heat source or the like to supply hot water. Cogeneration systems are highly energy efficient.

  In such a cogeneration system, generally, the supply stop of the hot water is determined when the amount of water of the water amount sensor that detects the flow rate of the supplied hot water becomes a predetermined amount or less. After the hot water supply stoppage determination, the mixing ratio of cold water and hot water is maintained for a predetermined time in order to stabilize the temperature at the time of re-heating. Even if a small amount of warm water flows during this period, it is determined that the supply is stopped, and thus the mixing ratio is not adjusted. Therefore, even if the set temperature is lowered when a small amount of hot water is flowing, hot water having a temperature higher than the set temperature continues to be supplied. In addition, after the hot water supply stop determination, heat is stored in the hot water storage tank, and even if the hot water in the hot water storage tank becomes hotter, the mixing ratio is not adjusted, so there is a risk that hot hot water will be unexpectedly supplied. is there. Techniques for preventing such high temperature hot water are required.

  Patent Document 1 describes a technique for preventing high temperature hot water in a cogeneration system. According to this technology, when a hot water supply temperature sensor that detects a hot water supply temperature during a hot water supply stop detection detects a temperature equal to or higher than a predetermined temperature, the mixing valve that mixes the hot water and the cold water is controlled to increase the ratio of the cold water to be mixed. . By increasing the mixing ratio of cold water, the temperature of hot water that is accidentally discharged can be lowered and safety can be increased.

JP 2007-3057 A

  However, according to the above technique, the hot water temperature sensor is provided downstream of the mixing valve. Therefore, when a high temperature is detected by the hot water supply temperature sensor, the high temperature hot water has already flowed downstream from the mixing valve. High temperature hot water cannot be completely prevented and safety cannot be ensured.

  The present invention has been proposed to solve the above problems. It is an object of the present invention to provide a cogeneration system that can prevent high-temperature hot water after the hot water supply stoppage determination and can ensure safety.

The present invention relates to a cogeneration system capable of heating water with generated heat generated by a power generation unit, storing the heated hot water, and supplying hot water using the stored hot water.
The cogeneration system of the present invention comprises a hot water storage tank for storing hot water, a hot water supply path for supplying hot water from the upper part of the hot water storage tank to the hot water use location, and a water supply path for supplying cold water from the cold water supply source to the lower part of the hot water storage tank. Yes. The cold water supply source is, for example, a water pipe.
The cogeneration system of the present invention is connected to a hot water supply path and a water supply path, and includes a mixing path that mixes cold water supplied from a cold water supply source with hot water supplied from a hot water storage tank.

The cogeneration system of the present invention is provided on a mixing path, and includes a mixing valve that adjusts a mixing ratio between a flow rate of cold water supplied from a cold water supply source and a flow rate of hot water supplied from a hot water storage tank. . The mixing valve may be provided at any position on the mixing path. The mixing ratio in this specification refers to the ratio of the flow rate of cold water supplied from a cold water supply source when the flow rate of hot water supplied from a hot water storage tank is 1.
The cogeneration system of this invention is equipped with the water quantity sensor which detects the flow volume of the warm water supplied to a hot water utilization location. The water amount sensor may be provided downstream of the connecting portion with the mixing path on the hot water supply path. Alternatively, since the amount of cold water supplied from the cold water supply source to the water supply path is equal to the flow rate of hot water supplied from the hot water supply path to the hot water use location, the water quantity sensor is located upstream from the connection with the mixing path on the water supply path. It may be provided.
The cogeneration system of the present invention includes a control valve that shuts off the supply of hot water from the hot water storage tank to the hot water supply path. The control valve may be provided upstream of the connection with the mixing path on the hot water supply path. Alternatively, since the flow rate of cold water supplied from the water supply path to the hot water storage tank is equal to the flow rate of hot water supplied from the hot water storage tank to the hot water supply path, the control valve is provided downstream of the connection portion with the mixing path on the water supply path. It may be done.

  In the cogeneration system of the present invention, when the flow rate detected by the water amount sensor becomes a predetermined amount or less, the mixing ratio of the cold water and the hot water at that time is maintained for a predetermined time, and the control valve is closed after the predetermined time has elapsed. The mixing ratio of cold water and hot water is maintained by keeping the mixing valve at a constant opening. When the hot water is discharged again in a short time after the hot water supply is stopped, the hot water supply temperature can be stabilized.

  According to the cogeneration system of the present invention, the supply of hot water from the hot water storage tank to the hot water supply path is interrupted after a predetermined time has elapsed since the flow rate of the hot water supplied to the hot water use location becomes a predetermined amount or less. Since the supply of hot water from the hot water storage tank to the hot water supply path is interrupted, only cold water is supplied to the hot water use location even if the opening degree of the mixing valve is maintained when determining the stop of supply of hot water. Even when heat storage in the hot water storage tank is performed after the hot water supply stop determination is made or when the set temperature is lowered, hot water of high temperature is not unexpectedly discharged. When hot water supply stoppage is determined, high temperature hot water can be prevented and safety can be ensured.

  The cogeneration system of the present invention is further provided with a first temperature sensor that is provided upstream of the connecting portion with the mixing path and downstream of the control valve and detects the temperature of hot water supplied from the hot water storage tank. It is preferable. In this case, when the flow rate detected by the water amount sensor becomes equal to or less than the predetermined amount, the temperature detected by the first temperature sensor at that time is stored, and then the temperature detected by the first temperature sensor is stored. It is preferable to close the control valve even before the predetermined time has elapsed when the temperature becomes higher than the predetermined temperature. In this case, it is preferable to set the predetermined temperature so that it does not fall within the error range of the first temperature sensor.

  If hot water is not supplied from the hot water storage tank to the hot water supply path after the hot water supply stop determination, the temperature detected by the first temperature sensor after the hot water supply stop determination gradually decreases due to heat dissipation in the hot water supply path. However, after the hot water supply stop determination, when the hot water storage is performed and the temperature of the hot water in the upper part of the hot water tank rises, if a small amount of hot water is supplied from the hot water storage tank to the hot water supply path, the first temperature sensor The temperature of the hot water detected increases. According to the cogeneration system, the control valve is closed when the temperature of the hot water detected by the first temperature sensor becomes higher than the predetermined temperature even within the predetermined time. Accordingly, hot hot water can be prevented from being discharged even within the predetermined time, and safety can be further improved.

  In the cogeneration system of the present invention, it is preferable to determine that the control valve has failed when the first temperature sensor detects a temperature equal to or higher than a predetermined temperature after closing the control valve.

  According to the cogeneration system described above, it is determined that the control valve has failed when the first temperature sensor detects a temperature equal to or higher than the predetermined temperature even though the control valve is closed. For control purposes, even if the hot water path from the hot water storage tank to the hot water supply path is interrupted, if the first temperature sensor detects a temperature equal to or higher than the predetermined temperature, the hot water is actually supplied from the hot water storage tank to the hot water supply path. The control valve is most likely broken. A failure of the control valve can be determined by monitoring the temperature of the hot water with the first temperature sensor, and safety can be further improved.

  In the cogeneration system of the present invention, it is preferable to adjust the mixing ratio to the maximum mixing ratio when it is determined that the control valve has failed.

  According to the above cogeneration system, when it is determined that the control valve is malfunctioning, the mixing ratio is set to the maximum mixing ratio and the cold water side is fully opened. If the mixing ratio is fully open on the cold water side, the temperature of the hot water discharged can be lowered. Hot water is not accidentally discharged when the control valve is out of order. Safety can be further increased.

  The cogeneration system of the present invention preferably further includes a water amount servo for controlling the flow rate of the hot water supplied to the hot water use location. In this case, when it is determined that the control valve has failed, it is preferable to control the water amount servo to shut off the hot water supplied to the hot water use location. The water amount servo may be provided downstream of the connecting portion with the mixing path on the hot water supply path. Alternatively, the amount of cold water supplied from the cold water supply source to the water supply path is equal to the flow rate of hot water supplied from the hot water supply path to the hot water use location, so the water volume servo is upstream of the connection with the mixing path on the water supply path. May be provided.

  According to the cogeneration system described above, when it is determined that the control valve has failed, the supply of hot water to the hot water use location is shut off. It is possible to prevent the hot water from being accidentally discharged when the control valve is malfunctioning regardless of the temperature of the hot water. Safety can be further increased.

  The cogeneration system of the present invention is further provided with a second temperature sensor that is provided on the hot water supply path downstream from the connection portion with the mixing path and detects the temperature of the hot water supplied to the hot water use location. Is preferred. In this case, when the flow rate detected by the water amount sensor becomes equal to or less than the predetermined amount, the temperature detected by the second temperature sensor at that time is stored, and then the temperature detected by the second temperature sensor is stored. It is preferable to close the control valve even before the lapse of a predetermined time when the temperature becomes higher than the predetermined temperature.

  According to the cogeneration system, it is possible to prevent unexpected hot water from being discharged even when hot water is supplied from the hot water storage tank within the predetermined time. Safety can be further increased. For example, even when the first temperature sensor is out of order, it is possible to prevent unexpected hot water from being discharged after hot water supply stoppage determination. Safety can be further increased.

  According to the cogeneration system of the present invention, it is possible to prevent an unexpected high-temperature hot water after the hot water supply stoppage determination and to ensure safety.

Preferred features of the embodiments described below are listed.
(First feature) When the flow rate detected by the hot water supply amount sensor is greater than or equal to a predetermined amount and the temperature detected by the hot water thermistor shows a value higher than the remote control set temperature by a predetermined temperature, the tank solenoid valve is closed and the tank Shut off the hot water supply path.
(Second feature) When the flow rate detected by the hot water supply amount sensor is greater than or equal to a predetermined amount, if the temperature detected by the hot water thermistor is higher than the remote control set temperature by a predetermined temperature, the water amount servo is fully closed. Shut off the hot water supplied to the hot water use location.
(3rd characteristic) When a tank solenoid valve is closed and a tank hot water supply path | route is interrupted | blocked, the opening degree of a mixer is restrict | limited.
(Fourth feature) After the hot water supply stop determination, if the temperature detected by the hot water thermistor exceeds the specified temperature, the tank solenoid valve is closed to shut off the tank hot water supply path.

(First embodiment)
In FIG. 1, the schematic diagram of the cogeneration system 100 which is 1st Example of this invention is shown. The cogeneration system 100 is connected to a hot-water tap 66b, a bath tub 66a, and the like, which are hot water usage points 66. The cogeneration system 100 includes a power generation unit 24, a hot water storage tank 18, a mixing unit 44, a remote controller 70, a controller 68, and the like.

  The power generation unit 24 is a power generation device using a solid polymer fuel cell. The power generation unit 24 generates power according to the power demand. When performing power generation, the power generation unit 24 drives the exhaust heat recovery pump 20. When the exhaust heat recovery pump 20 is driven, water is sucked out from the lower part of the hot water storage tank 18. The sucked water is heated by the generated heat in the exhaust heat recovery heat exchanger 22 and returned to the upper part of the hot water storage tank 18. The temperature of the hot water returned from the power generation unit 24 to the upper part of the hot water storage tank 18 is measured by the exhaust heat recovery thermistor 26 and output to the controller 68. When the temperature of the hot water returned to the upper part is low, the hot water storage tank 18 is bypassed by switching the three-way exhaust heat switching valve 28 to be returned to the power generation unit 24 and heated again.

  The hot water storage tank 18 stores hot water heated by the heat generated by the power generation unit 24. The hot water stored in the hot water storage tank 18 is used for hot water supply or bathing. A temperature stratification is formed inside the hot water storage tank 18, and hot water having a temperature higher than that of the lower part is stored in the upper part of the hot water storage tank 18. Therefore, even when the amount of heat stored in the hot water storage tank 18 is small, hot water can be used by discharging the hot water from the upper part of the hot water storage tank 18. A tank upper thermistor 32 for detecting the hot water temperature is provided at the upper part of the hot water storage tank 18, and the detected temperature is output to the controller 68.

  The lower part of the hot water storage tank 18 is connected to the water pipe (cold water supply source) 2 via the tank water supply path 16, the mixing unit 44 and the water supply path 4. A pressure reducing valve 6 is provided in the water supply path 4, and the water supply pressure from the water pipe 2 is adjusted. The upper part of the hot water storage tank 18 is connected to the hot water tap 66b via the tank hot water supply path 34, the mixing unit 44, and the hot water supply path 48. The tank hot water supply path 34 is provided upstream of the connection part 42 with the mixing path 40, and the hot water supply path 48 is provided downstream of the connection part 42 with the mixing path 40. When the hot water tap 66b is opened, the hot water in the hot water storage tank 18 is pushed up from the lower part to the upper part by the water supply pressure, and the hot water is discharged from the upper part of the hot water storage tank 18 to the tank hot water supply path 34. Hot water discharged from the hot water storage tank 18 is mixed with tap water by the mixing unit 44, adjusted to a desired temperature, and then supplied to the hot water tap 66b.

  The mixing unit 44 mixes tap water with hot water discharged from the upper part of the hot water storage tank 18 to adjust the temperature to a desired temperature. The mixing unit 44 branches a part of tap water flowing from the water supply path 4 to the tank water supply path 16 to the mixing path 40 and mixes it with hot water flowing from the tank hot water supply path 34 to the hot water supply path 48. A mixer (mixing valve) 14 is provided at a connecting portion of the water supply path 4, the tank water supply path 16, and the mixing path 40. The mixer 14 has a built-in stepping motor, and when this is driven, the opening of the tank water supply path 16 and the opening of the mixing path 40 are adjusted to mix with the flow rate of tap water flowing into the tank water supply path 16. The ratio of the flow rate of tap water flowing to the path 40 is adjusted. The flow rate of tap water supplied from the mixing unit 44 to the lower part of the hot water storage tank 18 is equal to the flow rate of hot water discharged from the upper part of the hot water storage tank 18 to the mixing unit 44. Therefore, by adjusting the ratio of the flow rate of tap water branched to the tank water supply path 16 by the mixer 14 and the flow rate of tap water branched to the mixing path 40, the tap water from the mixing path 40 and the tank hot water supply path 34 are adjusted. The mixing ratio of hot water can be adjusted.

  A tank solenoid valve (control valve) 36 and a hot water supply high temperature thermistor (first temperature sensor) 38 are provided in the tank hot water supply path 34. The tank solenoid valve 36 is controlled by a controller 68, and opens and closes when a built-in solenoid is driven. In the state where the tank solenoid valve 36 is closed, even if the hot-water tap 66b is opened, hot water is not discharged from the hot water storage tank 18, and tap water is supplied to the hot-water tap 66b via the water supply path 4 and the mixing path 40. . The hot water supply high temperature thermistor 38 detects the temperature of the hot water flowing through the tank hot water supply path 34 and outputs it to the controller 68.

  A hot water supply thermistor (second temperature sensor) 46 is provided in the hot water supply path 48. The hot water thermistor 46 detects the temperature of the hot water flowing through the hot water supply path 48 and outputs it to the controller 68.

  The water supply path 4 is provided with a water supply thermistor 8, a hot water supply amount sensor (water amount sensor) 10, and a hot water supply water amount servo (water amount servo) 12. The water supply thermistor 8 detects the temperature of the tap water flowing through the water supply path 4 and outputs it to the controller 68. The hot water supply amount sensor 10 detects the flow rate of tap water flowing through the water supply path 4 and outputs it to the controller 68. Since the flow rate of tap water flowing from the water supply path 4 to the mixing unit 44 is equal to the flow rate of hot water flowing from the mixing unit 44 to the hot water supply path 48, the flow rate detected by the hot water supply amount sensor 10 is the hot water supplied from the mixing unit 44. Is equal to the flow rate. The hot water supply amount servo 12 controls the flow rate of tap water flowing through the water supply path 4. Since the flow rate of tap water flowing from the water supply path 4 to the mixing unit 44 and the flow rate of hot water flowing from the mixing unit 44 to the hot water supply path 48 are equal, the flow rate of tap water flowing through the water supply path 4 is controlled by the mixing unit 44. The flow rate of the hot water flowing to the hot water supply path 48 can be controlled.

  On the upper and lower portions of the hot water storage tank 18, a path 29 a is provided through a three-way tank switching valve 30 toward a heat source machine (not shown). In the heat source machine, hot water in the hot water storage tank 18 is heated as necessary. The heated hot water is returned to the upper part of the hot water storage tank 18 from the path 29b. The hot water heated by the heat source device may be returned directly to the hot water storage tank 18, and for example, heat exchange is performed with a heat medium used as a heat source of the heating terminal, thereby heating the floor heating or bathing. In some cases, the hot water tank 18 is returned to the hot water storage tank 18 after being used. The hot water tank 18 may be supplied with hot water heated by the heat source device, or may be supplied with hot water heated by the power generation unit 24.

  A bath circulation path 62 is connected to the bath tub 66a. A bath pump 54, a bath water flow switch 56, and a bath thermistor 58 are provided in the bath circulation path 62. When the bath pump 54 is driven by the controller 68, hot water is sucked out from the bathtub 66a to the bath circulation path 62. The hot water sucked out of the bathtub 66a is heated by the bath heat exchanger 60 and returned to the bathtub 66a. The temperature of the hot water heated by the bath heat exchanger 60 is detected by a bathing thermistor 64.

  The bath circulation path 62 communicates with the hot water supply path 48 via the hot water filling valve 50 and the hot water filling amount sensor 52. By opening the hot water filling valve 50, hot water filling to the bathtub 66a is performed. The hot water filling valve 50 is controlled by the controller 68. The hot water quantity sensor 52 detects the quantity of hot water flowing from the hot water supply path 48 toward the bath circulation path 62. The temperature of hot water from the hot water supply path 48 toward the bath circulation path 62 is detected by a bath thermistor 58.

  The remote controller 70 includes a display board and operation switches. The user can operate the remote controller 70 to input ON / OFF of the operation of the cogeneration system 100, start / end of various operation modes, a hot water supply set temperature, a bath set temperature, and the like. The remote controller 70 can communicate with the controller 68 and transmits the user's operation contents to the controller 68.

  The controller 68 stores a control program. The controller 68 receives an operation signal from the remote controller 70, a detection signal from the hot water supply amount servo 12, detection signals from various thermistors, and the like. The controller 68 processes the input signal with a control program, and controls various pumps, various valves, the mixer 14 and the like. The controller 68 has a built-in timer counter.

  FIG. 2 shows a flowchart for explaining the operation of the cogeneration system 100. Hereinafter, the flowchart will be described. In the flowchart, TH represents a thermistor.

  In step S102, the process waits until hot water supply is started. In this embodiment, hot water supply is started when the detected flow rate of the hot water supply amount sensor 10 becomes 2.7 liters / min or more, that is, when the flow rate of the hot water supply passage 48 becomes 2.7 liters / min or more. Judge that When hot water supply is started (YES in step S102), the process proceeds to step S104. If the flow rate of the hot water supply path 48 is less than 2.7 liters / min, it is determined that hot water supply has not started (NO in step S102), and the process returns to step S102 until hot water supply is started (hot water supply path 48). Wait until the flow rate becomes 2.7 liters / min or more.

In step S104, the tank solenoid valve 36 is opened. As a result, the hot water stored in the upper part of the hot water storage tank 18 is sent out to the tank hot water supply path 34. In the mixer 14, the opening degree is adjusted to a mixing ratio at which the temperature of the hot water discharged is equal to the temperature set by the remote controller 70, and hot water is supplied from the tank hot water supply path 34 to the hot water use point 66 (hot water tap 66 b, bath tub 66 a). Is started. The mixing ratio adjusted by the mixer 14 is calculated by the following equation.
Mixing ratio = (hot water supply high temperature thermistor detection temperature−remote control set temperature) / (remote control set temperature−water supply thermistor detection temperature)

  In step S106, the failure of the mixer 14 is determined. In this embodiment, when the temperature detected by the tapping thermistor 46 detects a value 5 ° C. or more higher than the set temperature of the remote controller 70 for 10 seconds or more, it is determined that the mixer 14 has failed (in step S106). In the case of YES), the process proceeds to step S108. When it is determined that the mixer 14 has not failed (NO in step S106), the process proceeds to step S110.

  In step S108, the tank solenoid valve 36 is closed to shut off the tank hot water supply path 34. Further, the hot water supplied to the hot water use point 66 is shut off by fully closing the hot water supply amount servo 12. Further, the abnormality of the mixer 14 is notified via the remote controller 70.

  In step S110, it is determined whether or not hot water supply has been completed. In this embodiment, when the detected flow rate of the hot water supply amount sensor 10 becomes 2.0 liters / min or less, it is determined that the hot water supply has ended (in the case of YES in step S110), and the process proceeds to step S112. When the hot water supply is not completed (NO in step S110), the process returns to step S104 and the hot water supply is continued.

  In step S112, the state where the tank electromagnetic valve 36 is opened is maintained. Moreover, the opening degree of the mixer 14 is maintained in the state at the time of hot water supply. As a result, even if hot water supply is resumed after determination of hot water supply stop, hot water supply can be started at a temperature that has been discharged at the previous hot water supply. The hot water supply temperature can be stabilized when the hot water is discharged again until the tank solenoid valve 36 is closed.

  In step S114, the detected temperature of hot water supply thermistor 38 (= a ° C.) and the detected temperature of hot water thermistor 46 (= b ° C.) at the time of hot water supply stop determination are stored. Next, high temperature hot water prevention processing (illustration A) is performed.

  FIG. 3 is a flowchart showing details of the high temperature hot water prevention processing. Hereinafter, the flowchart will be described.

  In step S152, is the difference between the temperature detected by hot water supply high temperature thermistor 38 and the detected temperature (a ° C.) of hot water supply high temperature thermistor 38 stored at step S114 shown in FIG. to decide. If there is a difference of α ° C. or more (YES in step S152), the process proceeds to S154. If the difference is smaller than α ° C. (NO in step S152), the process proceeds to S156. Here, α is a numerical value that is not less than the measurement error range of the hot water supply high temperature thermistor 38.

  In step S154, the tank solenoid valve 36 is closed and the tank hot water supply path 34 is shut off. Further, the opening degree of the mixer 14 is limited to the water side. The opening degree of the mixer 14 cannot be fully opened on the hot water side. Next, an open failure determination process (B in the figure) of the tank electromagnetic valve 36 is performed.

  In step S156, it is determined whether or not the difference between the temperature detected by the hot water thermistor 46 and the detected temperature (b ° C.) of the hot water thermistor 46 stored in step S114 shown in FIG. . If there is a difference of β ° C. or more (YES in step S156), the process proceeds to step S154. If the difference is smaller than β ° C. (NO in step S156), the process proceeds to step S158. Here, β is a numerical value that is not less than the measurement error range of the tapping thermistor 46.

  In step S158, it is determined whether the temperature detected by the hot water thermistor 46 is equal to or higher than a specified temperature (for example, 45 ° C.). If the temperature is equal to or higher than the specified temperature (YES in step S158), the process proceeds to step S154. If the specified temperature is not exceeded (NO in step S158), the process proceeds to step S160.

  In step S160, it is determined whether a predetermined time has elapsed since it was determined in step S110 shown in FIG. If the predetermined time has elapsed (YES in step S160), the process proceeds to step S162. If the predetermined time has not elapsed (NO in step S160), the process returns to step S152.

  In step S162, the tank solenoid valve 36 is closed and the tank hot water supply path 34 is shut off. In addition, since it is necessary to ensure the re-watering performance after 5 minutes after the hot water supply stop determination, the predetermined time described in step S160 is at least 5 minutes or more. In step S162, the opening degree of the mixer 14 is returned to the initial setting position. When the opening is returned to the initial position, an open failure determination process (B in the figure) for the tank solenoid valve 36 is performed.

  FIG. 4 is a flowchart showing details of the open failure determination process for the tank solenoid valve 36. Hereinafter, the flowchart will be described.

  After the tank electromagnetic valve 36 is closed, an open failure determination of the tank electromagnetic valve 36 is made in step S202. In the present embodiment, when the detected value of the hot water supply high temperature thermistor 38 detects a value 5 ° C. or more higher than the remote control set temperature for 10 seconds or more despite the tank solenoid valve 36 being closed (in the case of YES in step S202). ), It is determined that the tank solenoid valve 36 has an open failure, and the process proceeds to S206. If the detected value of the hot water supply high temperature thermistor 38 does not detect a temperature higher by 5 ° C. or more than the remote controller set temperature, or if the detected temperature does not continue for 10 seconds or longer (NO in step S202), the process proceeds to step S204. In this embodiment, if the temperature does not continue for 10 seconds even if a temperature higher by 5 ° C. than the remote control set temperature is detected, it is considered that the hot water thermistor 38 is within the measurement error range, and the tank solenoid valve 36 is broken open. I do not judge.

  In step S204, the open failure determination of the tank solenoid valve 36 is performed by a process different from the above. In this embodiment, when the detected value of the hot water thermistor 46 detects a value 5 ° C. or more higher than the remote controller set temperature for 10 seconds or more (YES in step S204), it is determined that the tank solenoid valve 36 is in an open failure condition. The process proceeds to S206. If the detected value of the hot water thermistor 46 does not detect a temperature higher than the remote control set temperature by 5 ° C. or more, or if the detected temperature does not continue for 10 seconds or longer (NO in step S204), the tank solenoid valve 36 is normal. It returns to S102 shown in FIG. In this embodiment, even if a temperature higher than the remote control set temperature is detected by 5 ° C. or more, if that state does not continue for 10 seconds, it is considered that the hot water thermistor 46 is within the measurement error range, and the tank solenoid valve 36 has failed to open. I do not judge it.

  In step S206, the abnormality of the tank electromagnetic valve 36 is notified via the remote controller 70. Moreover, the opening degree of the mixer 14 is adjusted to water side full open. If the opening degree of the mixer 14 is fully opened on the water side, the temperature of hot water that is erroneously discharged can be lowered. When the tank solenoid valve 36 is out of order, high temperature hot water is not accidentally discharged. Safety can be further increased.

  In step S208, the hot water supply amount servo 12 is fully closed. When it is determined that the tank solenoid valve 36 is out of order, the hot water supply servo 12 is fully closed to cut off the supply of hot water to the hot water usage point 66. Safety can be further increased.

  In the cogeneration system 100 of the present embodiment, after the amount of water detected by the hot water supply amount sensor 10 becomes less than a predetermined amount (after determination of hot water supply stop), the temperature is unexpectedly higher than the temperature set by the remote controller 70 during normal hot water supply. This hot water is not accidentally supplied to the hot water use point 66. Even when the amount of water detected by the hot water supply amount sensor 10 is equal to or greater than a predetermined amount (during hot water supply), unexpectedly high temperature hot water higher than the temperature set by the remote controller 70 is erroneously supplied to the hot water use location 66. There is no end. In the cogeneration system 100 of the present embodiment, safety against high temperature hot water is ensured.

  In the cogeneration system 100, when the flow rate detected by the hot water supply amount sensor 10 is 2.7 liter / min or more (at the time of hot water supply determination) in step S106, the temperature detected by the hot water thermistor 46 is the set temperature of the remote controller 70. If a value higher than 5 ° C. is detected for 10 seconds or longer, the tank solenoid valve 36 is closed and the tank hot water supply path 34 is shut off in step S108. Since the hot water thermistor 46 is provided downstream from the connection portion 42 to the mixing path 40, the difference between the temperature of the hot water supplied to the hot water use location 66 (detected temperature of the hot water thermistor 46) and the set temperature of the remote controller 70. Is large, there is a high possibility that the mixer 14 has failed. Therefore, when the temperature detected by the hot water thermistor 46 when the tank solenoid valve 36 is opened detects a value higher than the set temperature of the remote controller 70 by 5 ° C. or more for 10 seconds or more, the mixer 14 is broken. Judge. When it is determined that the mixer 14 is out of order, the tank solenoid valve 36 is closed, so that hot hot water is prevented.

  In the cogeneration system 100, when the flow rate detected by the hot water supply amount sensor 10 is 2.7 liter / min or more (at the time of hot water supply determination) in step S106, the temperature detected by the hot water thermistor 46 is the set temperature of the remote controller 70. If a value higher than 5 ° C. is detected for 10 seconds or longer, the hot water supplied to the hot water use point 66 is shut off by fully closing the hot water supply amount servo 12 in step S108. Since the hot water thermistor 46 is provided downstream from the connection portion 42 to the mixing path 40, the difference between the temperature of the hot water supplied to the hot water use location 66 (detected temperature of the hot water thermistor 46) and the set temperature of the remote controller 70. Is large, there is a high possibility that the mixer 14 has failed. When it is determined that the mixer 14 is out of order, the hot water supply servo 12 is fully closed, whereby the supply of hot water to the hot water use point 66 is shut off. Safety can be further increased.

  In the cogeneration system 100, when the tank solenoid valve 36 is closed and the tank hot water supply path 34 is shut off in step S154, the opening degree of the mixer 14 is limited to the water side. After the hot water supply stop determination, if the tank solenoid valve 36 is closed when the opening degree of the mixer 14 is fully open, tap water is not supplied to the mixing path 40, so the hot water supply amount sensor 10 can detect the amount of water. Can not. By restricting the opening of the mixer 14 to the water side when the tank hot water supply path 34 is shut off, the amount of water can be detected even when the tank electromagnetic valve 36 is closed, and good re-watering performance is obtained. Can do.

  In the cogeneration system 100, when the temperature detected by the hot water thermistor 46 indicates a specified temperature (for example, 45 ° C.) or higher in step S158, the tank electromagnetic valve 36 is closed and the tank hot water supply path 34 is shut off in step S154. . Even if the set temperature of the remote controller 70 is changed after the hot water supply stop determination is made, hot water above the specified temperature is not discharged. It is possible to prevent hot hot water from being discharged, and safety is ensured.

As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the cogeneration system according to the embodiment of the present invention, the power generation unit is a power generation device using a fuel cell, but the power generation unit may be a power generation device using a fuel cell other than the fuel cell.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

The schematic diagram of the cogeneration system 100 which is 1st Example is shown. 2 is a flowchart illustrating the operation of the cogeneration system 100. The flowchart of the process which prevents high temperature hot-water supply is shown. The flowchart of the process which judges the open failure of a tank solenoid valve is shown.

Explanation of symbols

2: Water pipe (cold water supply source)
4: Water supply path 6: Pressure reducing valve 8: Water supply thermistor 10: Hot water supply water amount sensor (water amount sensor)
12: Hot water amount servo (water amount servo)
14: Mixer (mixing valve)
16: Tank water supply path 18: Hot water storage tank 20: Waste heat recovery pump 22: Waste heat recovery heat exchanger 24: Power generation unit 26: Waste heat recovery thermistor 28: Three-way exhaust heat switching valves 29a, 29b: Path 30: Three-way tank switching Valve 32: Tank upper thermistor 34: Tank hot water supply path 36: Tank solenoid valve (control valve)
38: Hot water supply high temperature thermistor (first temperature sensor)
40: Mixing path 42: Connection between tank hot water supply path, mixing path and hot water supply path 44: Mixing unit 46: Hot water thermistor (second temperature sensor)
48: Hot water supply route 50: Hot water filling valve 52: Hot water filling amount sensor 54: Bath pump 56: Bath water amount switch 58: Bath thermistor 60: Bath heat exchanger 62: Bath circulation route 64: Bathing thermistor 66: Hot water use point 66a : Bathtub 66b: Hot water tap 68: Controller 70: Remote control

Claims (6)

A cogeneration system capable of heating water with generated heat generated by a power generation unit, storing heated hot water, and supplying hot water using the stored hot water,
A hot water storage tank for storing hot water,
A hot water supply path for supplying hot water from the upper part of the hot water storage tank to the hot water use point,
A water supply path for supplying cold water from a cold water supply source to the lower part of the hot water storage tank;
A hot water supply path and a water supply path are connected, and a mixing path for mixing cold water supplied from a cold water supply source with hot water supplied from a hot water storage tank;
A mixing valve that is provided on the mixing path and adjusts a mixing ratio between a flow rate of cold water supplied from a cold water supply source and a flow rate of hot water supplied from a hot water storage tank;
A water volume sensor for detecting the flow rate of hot water supplied to the hot water use location;
It has a control valve that shuts off the supply of hot water from the hot water storage tank to the hot water supply path.
A cogeneration system that maintains the mixing ratio of cold water and hot water at a time for a predetermined time when the flow rate detected by the water amount sensor becomes a predetermined amount or less, and closes the control valve after the predetermined time has elapsed. Provided on a hot water supply path upstream of the connection with the mixing path and downstream of the control valve, further comprising a first temperature sensor for detecting the temperature of hot water supplied from the hot water storage tank;
When the flow rate detected by the water amount sensor becomes equal to or less than the predetermined amount, the temperature detected by the first temperature sensor at that time is stored, and then the temperature detected by the first temperature sensor is The cogeneration system according to claim 1, wherein the control valve is closed even when the predetermined time has not elapsed when the temperature becomes higher than a stored temperature by a predetermined temperature or more.   3. The cogeneration system according to claim 2, wherein after the control valve is closed, the control valve determines that the control valve has failed when the first temperature sensor detects a temperature equal to or higher than a predetermined temperature.   The cogeneration system according to claim 3, wherein when it is determined that the control valve has failed, the mixing ratio is adjusted to a maximum mixing ratio. It is further equipped with a water volume servo that controls the flow rate of hot water supplied to the hot water usage point,
4. The cogeneration system according to claim 3, wherein when it is determined that the control valve has failed, the water quantity servo is controlled to shut off the hot water supplied to the hot water use location. Provided on the hot water supply path downstream from the connection with the mixing path, further comprising a second temperature sensor for detecting the temperature of the hot water supplied to the hot water use location;
When the flow rate detected by the water amount sensor becomes equal to or less than the predetermined amount, the temperature detected by the second temperature sensor at that time is stored, and then the temperature detected by the second temperature sensor is The cogeneration system according to any one of claims 1 to 5, wherein the control valve is closed even before the predetermined time has elapsed when the temperature becomes higher than a stored temperature by a predetermined temperature or more.

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