JP6044135B2 - Cogeneration system - Google Patents

Description

  The present invention provides a hot water heating using heat generated in a power generation unit using a gas engine, a fuel cell, etc., and the hot water is stored in a hot water storage tank before being used for hot water supply. Regarding generation systems.

  Conventionally, there exists a thing of patent document 1 as an example of a cogeneration system. In the system described in the document, hot water from a hot water storage tank is stored in a bathtub when the amount of heat stored in the hot water storage tank approaches a full state during self-sustained power generation (power generation without external power supply) such as when a power failure occurs. The hot water supply process to supply to is performed. This hot water treatment reduces the amount of heat stored in the hot water storage tank. When the amount of heat stored in the hot water storage tank is full, hot water heated using the exhaust heat from the power generation unit cannot be stored in the hot water storage tank any more, making it difficult to recover the heat generated in the power generation unit. There is a risk that the power generation unit may be in an overheated state. On the other hand, according to the above-described configuration, there is an advantage that such a fear can be avoided and the independent power generation can be continued.

  However, there is still room for improvement in the prior art as described below.

  That is, the hot water treatment from the hot water storage tank is executed when the heat storage amount of the hot water storage tank is almost full as described above, but of course when the hot water supply operation switch is turned on, Even when the hot water supply operation switch is turned off, the hot water supply operation switch is forcibly switched to the on state. For this reason, when the user opens the tap with the hot water supply operation switch turned off and uses unheated water, the hot water supply operation switch is forced to execute the hot water discharge processing from the hot water storage tank. May be switched to the ON state automatically. When such a situation occurs, hot water adjusted to a preset target hot water temperature is supplied to the tip plug, but the target hot water temperature is high (for example, 55 ° C., etc.). ), Hot water is supplied from the tip. Although the user is trying to avoid the use of heated hot water by turning off the hot water supply operation switch, hot water is supplied against the user's will as described above. In addition, there is a possibility that the user may touch hot water. Therefore, it is desirable to appropriately prevent such a situation.

JP 2009-204239 A

  The present invention has been conceived under the circumstances as described above, and when the user intends to use unheated water by turning off the hot water supply operation switch, the drive of the power generation unit is continued. It is an object of the present invention to provide a cogeneration system capable of appropriately preventing high temperature hot water from being generated due to the execution of a target hot water discharge process.

  In order to solve the above problems, the present invention takes the following technical means.

A cogeneration system provided by the present invention includes a heat recovery heat exchanger capable of recovering heat generated in a power generation unit and performing hot water heating, and hot water heated using the heat exchanger. Hot water storage tank that can store water, and when the hot water supply operation switch is on, the hot water discharged from the hot water storage tank can be adjusted to a preset target hot water temperature and supplied to a desired hot water supply destination. A control means, wherein the control means is configured to specify that when the power generation unit is driven, the amount of heat stored in the hot water storage tank is equal to or greater than a predetermined amount, and at that time, the hot water supply operation switch is turned off. When a state occurs, the hot water supply operation switch is turned on and then the hot water in the hot water storage tank is supplied to a bathtub or a predetermined place instead of the bathtub. The control for executing the Haiyu process for reducing the heat storage amount of the hot water storage tank is capable, a cogeneration system, the control means, for supplying hot water heated or not to the desired hot water destination It is possible to determine whether or not hot water flow is occurring in the hot water flow path, and when the hot water supply operation switch is switched from the off state to the on state due to the occurrence of the specific state, When it is determined that hot water circulation has occurred, hot water supply temperature lowering control is performed to lower the subsequent hot water supply temperature to a target hot water temperature set before that, while hot water circulation is performed in the hot water flow path. If it is not determined that the hot water supply has occurred, the hot water temperature lowering control is not executed .
Here, “on state of hot water supply operation switch” is a mode that allows hot water supply from a hot water storage tank to a desired hot water supply destination (hot water supply operation allowable mode, for example, detection of a water flow of a predetermined amount or more when the tip is opened. Is the same as the setting state of the mode in which heated hot and cold water is discharged), which means either hot water supply to the desired hot water supply destination is actually being performed or standby state in which such hot water supply is not being performed. It doesn't matter if it is. However, as an exception, even when the hot water supply operation switch is on, if a predetermined abnormality is detected and a safety operation corresponding to this abnormality is executed and operation is forcibly prohibited, The hot water supply operation prohibition mode is set instead of the allowable mode.
On the other hand, the “off state of the hot water supply operation switch” means that, for example, even when a tip plug provided in the hot water supply system is opened, the hot water supply from the hot water storage tank to the tip plug is not executed and the non-heated water supply system is not heated. This is synonymous with the setting state of the mode in which water is supplied (hot water supply operation stop mode).

According to the present invention, in a situation where the user intends to use unheated water with the hot water operation switch turned off, the hot water discharge processing from the hot water storage tank is executed for the purpose of continuing driving of the power generation unit. Even if the hot water supply operation switch is turned on as much as possible and hot water is supplied to a predetermined hot water supply destination, the hot water is controlled to a temperature lower than the previous target hot water temperature. Therefore, even if the target hot water supply temperature is set to a high temperature (for example, 55 ° C. or the like), the supply of the high temperature hot water at that temperature to the desired hot water supply destination is avoided. As a result, it is possible to prevent the user from accidentally touching hot hot water.
Further, according to the above configuration, when hot water circulation occurs in the predetermined hot water flow path and hot water is supplied to the hot water supply destination, the hot water supply temperature lowering control is executed. Abrupt supply is adequately avoided. On the other hand, when no hot water circulation occurs in the hot water flow path and no hot water is supplied to the hot water supply destination, the hot water supply temperature lowering control can be prevented from being performed unnecessarily.

  In the present invention, it is preferable that the hot water supply temperature decrease control is executed when a target hot water temperature set before the specific state occurs is higher than a predetermined temperature, and is not executed otherwise. ing.

  According to such a configuration, when the target hot water supply temperature is a high temperature that is equal to or higher than a predetermined temperature and there is a risk of causing burns or the like to the user, for example, On the other hand, if the target hot water supply temperature is set to a relatively low temperature that does not have such a risk, the hot water supply temperature lowering control is not executed. Accordingly, the hot water supply temperature lowering control is efficiently executed only when the necessity is high.

  In the present invention, preferably, when the hot water treatment is performed, the heat dissipation amount from the hot water storage tank is not less than the heat recovery amount by the heat recovery heat exchanger. The amount of discharged hot water and its temperature are controlled.

  According to such a configuration, when performing the hot water treatment from the hot water storage tank, the amount of the hot water is prevented from becoming excessively small, and the problem that the heat storage amount of the hot water storage tank is unduly increased and becomes full is properly obtained. Can be prevented. Therefore, it is more preferable to ensure that the driving of the power generation unit is continued.

  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention with reference to the accompanying drawings.

It is a schematic explanatory drawing which shows an example of the cogeneration system which concerns on this invention. It is a flowchart which shows an example of the operation processing procedure of the control part of the cogeneration system of FIG.

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

  The cogeneration system C shown in FIG. 1 includes a power generation unit U1 and a hot water supply unit U2. The basic hardware configuration of the cogeneration system C is the same as that of Patent Document 1. Therefore, the known configuration common to Patent Document 1 will be described relatively simply.

The power generation unit U1 includes a power generation unit 10, a cooling circuit 11, a power circuit 12, and a control unit 13.
The power generation unit 10 is a method of rotating the generator 10b using, for example, a gas engine 10a. As will be described later, instead of this, the power generation unit 10 may be a fuel cell system.
The cooling circuit 11 is a circuit for cooling (water cooling) the power generation unit 10 by recovering heat from the exhaust gas of the gas engine 10a, and is configured so that hot water for water cooling circulates through a fixed path by driving the pump P1. Has been. After the hot water flowing through the cooling circuit 11 passes through the power generation unit 10 and rises in temperature, it is sent to the heat exchanger 24 for heat recovery provided in the hot water supply unit U2 and sent from the hot water storage tank 20. Used to heat the hot water.

  The power generation unit U1 is normally operated by receiving power from the external power supply to the power supply circuit 12, and can supply the power generated in the power generation unit 10 to the external device of the power generation unit U1. However, power generation (self-sustaining power generation) is possible even when the external power supply is interrupted. The start of the gas engine 10a during this self-sustaining power generation may be either a method using a cell motor driven by a charging battery or a manual method. The control unit 13 performs operation control and data processing of each unit of the power generation unit U1, and is configured by using, for example, a microcomputer (this also applies to the control unit 22 described later).

  The hot water supply unit U2 is a unit for performing hot water supply (general hot water supply) to the tip plug 30, hot water filling operation to the bathtub 31, and the like, and includes a hot water storage tank 20, an auxiliary heat source device 21, a control unit 22, and a power supply circuit. 23, a heat exchanger 24 for heat recovery, and various devices described later.

  Storage of heated hot water in the hot water storage tank 20 is executed by driving the pump P2. When the pump P2 is driven, the hot water in the hot water storage tank 20 flows as indicated by arrows N11 to N13. More specifically, the hot water in the hot water storage tank 20 passes through the lower pipe portion 50a and the pipe portion 50b having the pump P2 and is sent to the heat exchanger 24 for heat recovery, where it is heated in the heat exchanger 24. The Thereafter, the hot water passes through the auxiliary heat source device 21, the flow rate control valve V1, and the upper pipe portion 50c and flows into the upper portion of the hot water storage tank 20. Therefore, hot water in the hot water storage tank 20 is sequentially accumulated from the upper side. The auxiliary heat source device 21 has the same configuration as, for example, an instantaneous gas water heater, and is used to heat the hot water when the temperature of the hot water sent to the auxiliary heat source device 21 is less than a predetermined temperature. . A plurality of temperature sensors Sa are attached to the hot water storage tank 20, and the amount of heat stored in the hot water storage tank 20 can be detected by the control unit 22 based on the hot water temperature distribution in the hot water storage tank 20. Note that the “heat storage amount” does not have to be the heat amount itself stored in the hot water storage tank 20, and may be, for example, the ratio of hot water having a predetermined temperature or more in the hot water storage tank 20.

  The control unit 22 performs operation control and data processing of each unit of the hot water supply unit U2, and can perform data communication with the control unit 13 of the power generation unit U1. At least one remote controller 4 is communicatively connected to the control unit 22. The remote controller 4 has a data display section 40 and a plurality of operation switches 41, and also includes a hot water supply operation switch 41a as one of them. When the hot water supply operation switch 41a is in the OFF state, the hot water supply operation is not executed, and when the tip tap 30 is opened, water such as tap water supplied to the water inlet 51 is directly supplied to the tip plug 30. Supplied. The flowing water path in this case is a path that sequentially passes through the piping parts 51a to 51c as indicated by arrows N21 to N23.

  When the hot water supply operation switch 41a is in the ON state, hot water supply to the tip plug 30, hot water filling to the bathtub 31 and bathing operation can be performed. These operations are also basically the same as in Patent Document 1. As indicated by arrows N31, N32, and N23, hot water to the plug 30 is obtained when hot water in the hot water storage tank 20 passes through the upper pipe portion 50c, the mixing valve V2, the bypass pipe portion 50d, and the pipe portions 51b and 51c. Done. In the mixing valve V2, the mixing ratio of the hot water from the hot water storage tank 20 and the water from the water inlet 51 is controlled, and the hot water temperature is adjusted. The hot water filling the bathtub 31 flows from the upper part of the hot water storage tank 20 and passes through the three-way valve V2 and the piping part 51b, and then the hot water of the bathtub passes through the piping part 51d as indicated by arrows N41 and N42. It reaches the circulation path 52 and flows into the bathtub 31 from both the forward pipe 52a and the return pipe 52b. The piping parts 51b and 51d are provided with flow sensors Sb and Sc, a flow control valve V3, and an on-off valve V4. The bath reheating operation is performed by using the heat exchanger 25 for reheating while circulating the hot water in the bathtub 31 in the bathtub hot water circulation path 52 by driving the pump P3. Hot water that has passed through the auxiliary heat source device 21 is supplied to the reheating heat exchanger 25 via a piping portion 53 having an on-off valve V5.

  The hot water supply unit U2 is operated using the power received by the power supply circuit 23 from the external power supply during normal times, and is operated using the power generated by the power generation unit U1 during a power failure of the external power supply. Such switching of the power supply source may be configured to be executed under the control of the control unit 22, but instead, for example, the power supply circuit 23 of the hot water supply unit U2 is used as the power output unit of the power generation unit U1. On the other hand, it is also possible to adopt a method in which wiring is connected manually.

When the heat storage amount of the hot water storage tank 20 exceeds a predetermined amount during the self-sustaining power generation of the power generation unit 10, the control unit 22 performs control to execute a hot water discharge process for sending hot water in the hot water storage tank 20 into the bathtub 31. . This hot water discharge process is performed through the same route as the hot water filling operation to the bathtub 31 described above. As a result of this hot water treatment, in the hot water storage tank 20, the amount of heat storage decreases and a margin for heat storage occurs, so that the heat recovered using the heat exchanger 24 is sequentially accumulated in the hot water storage tank 20 thereafter. be able to.
The controller 22 is configured to execute hot water supply temperature lowering control under a predetermined condition so as to prevent the hot water from being inadvertently supplied to the tip plug 30 during the above-described hot water discharge process. Yes. The specific contents will be described later.

  Next, the operation of the above-described cogeneration system C will be described. In addition, an example of an operation processing procedure of the control unit 22 will be described with reference to the flowchart of FIG.

  First, when self-sustaining power generation of the power generation unit 10 is executed due to a power failure of the external power source and the amount of heat stored in the hot water storage tank 20 exceeds a predetermined amount, the control unit 22 turns on the hot water supply operation switch 41a. -It is determined which of the OFF states (S1: YES, S2: YES, S3). Here, the above-mentioned “heat storage amount is the predetermined amount” is an amount smaller than the full amount of the heat storage amount, for example, when high-temperature hot water having a predetermined temperature or more reaches about 2/3 of the capacity of the hot water storage tank 20. Is possible. However, the specific numerical values are not limited. The “predetermined amount” may be changed by a switch operation of the remote controller 4.

  When the hot water supply operation switch 41a is in the on state in step S3, the control unit 22 executes the hot water discharge process without performing any special control thereafter (S3: NO, S8, S9: YES). . As described above, the hot water discharge process is a process of supplying hot water from the hot water storage tank 20 to the bathtub 31. By this process, the heat storage amount of the hot water storage tank 20 is reduced and the heat storage margin is increased. For this reason, it is possible to continue the process of accumulating the heat recovered by the heat recovery heat exchanger 24 in the hot water storage tank 20 and to continue the self-sustaining power generation without fear of the power generation unit 10 overheating. In the case where the above-described hot water discharge process is being performed, for example, when the front plug 30 is opened, hot water having the target hot water temperature set by the remote controller 4 is supplied. However, in this case, since the user recognizes in advance by looking at the display unit 40 of the remote controller 4 that the hot water supply operation switch 41a is on, and intends to use hot water from the beginning, Unlike the case where the hot water supply operation switch 41a is set to the OFF state, there is no particular problem even if hot water at the target hot water supply temperature is supplied to the tip plug 30 during the hot water discharge process.

  Unlike the above, in step S3, when the hot water supply operation switch 41a is in the OFF state, the control unit 22 determines, as a first determination matter, whether or not the tip plug 30 is in the open state, specifically, Determines whether the water flow is detected using the flow sensor Sb (S4). Note that the state where both steps S2 and S3 are “YES” corresponds to the “specific state” in the present invention. If there is water flow detection using the flow rate sensor Sb in the determination, the control unit 22 determines whether the target hot water supply temperature is set to a predetermined temperature (for example, 50 ° C.) or more as a second determination matter. (S4: YES, S5). When both of these first and second determination items are “YES”, the control unit 22 lowers the target hot water supply temperature to a predetermined temperature (for example, 40 ° C.), and then turns on the hot water supply operation switch 41a. Hot water processing is executed (S4: YES, S5: YES, S6 to S8, S9). The control for lowering the target hot water supply temperature to 40 ° C. corresponds to an example of the hot water supply temperature lowering control in the present invention. In the system C of the present embodiment, the hot water supply priority mode is adopted, and the hot water discharge process in step S8 is started when the water flow detection by the flow rate sensor Sb is stopped by closing the tip plug 30. However, it is not limited to this.

According to the above-described control, when the user turns off the hot water supply operation switch 41a and uses non-heated hot water, for example, 40 ° C. hot water may be supplied to the tip plug 30, but 50 ° C. The trouble that the above high-temperature hot water is unfairly supplied to the tip plug 30 is appropriately avoided. Therefore, a sense of security can be given to the user. Further, even when the hot water supply operation switch 41a is turned off, the hot water supply operation switch 41a is forcibly turned on and the hot water discharge process is appropriately executed. It is possible to appropriately realize that the power generation unit 10 continues the self-sustaining power generation.

  Unlike the above, when there is no water flow detection using the flow sensor Sb (S4: NO), or when the target hot water supply temperature is not higher than the predetermined temperature (S5: NO), the target hot water supply temperature is lowered. Without this, the hot water supply operation switch 41a is turned on to execute the hot water discharge process (S4: NO or S5: NO, S7, S8). In this case, there is no possibility that high temperature hot water is generated or less, and the process of lowering the target hot water temperature is omitted.

  Although not shown in the flowchart of FIG. 2, after the hot water discharge process is completed (S9: YES), the hot water supply operation switch 41a is turned on and off, and the target hot water temperature is returned to the original state. Good. More specifically, when the hot water discharge process is performed via step S7, the hot water supply operation switch 41a may be returned to the original OFF state when the hot water discharge process is completed. The same applies to the target hot water temperature, and when the target hot water temperature is initially set to, for example, 50 ° C. or higher, the target hot water temperature may be returned to such a temperature after the hot water discharge process. Of course, a configuration in which such a return operation is not executed may be employed.

  In the present embodiment, when the above-described hot water discharge process is executed, the hot water supply temperature t0 to the bathtub 31 and the hot water supply amount Q0 to the bathtub 31 can be determined as follows. This process can be executed by a control unit (not shown) mounted on the remote controller 4 in place of the control unit 22 to reliably prevent the heat storage amount of the hot water storage tank 20 from becoming full. Useful.

[Determination of hot water supply temperature t0]
Hot water supply temperature t0 is determined by either of the following methods 1 and 2. However, hot water supply temperature t0 is not set to a high temperature exceeding a predetermined temperature, for example, 48 ° C. is set as the upper limit temperature.
[Method 1]
The target hot water supply temperature t1 set before the hot water discharge process is compared with the incoming water temperature t2 (temperature detected by the temperature sensor Sd), and when t1 >> t2, the hot water supply temperature t0 = t1.
If t1 >> t2 is not satisfied, t0 = t1 + α1. Here, α1 is a positive value larger than zero.
[Method 2]
The target hot water supply temperature t1 set before the hot water discharge process is compared with a predetermined reference temperature t3 (for example, 40 ° C.). When t1> t3, t0 = t1. Otherwise, t0 = t3.

[Determination of hot water supply amount Q0 to bathtub 31]
It is determined based on either of the following formulas 1 and 2.
[Formula 1]
Hot water supply amount Q0 = (T1 + T2) · Q1 / (t0−t2) + α2
[Formula 2]
Hot water supply amount Q0 = [(T1 + T2) · Q1 / (t0−t2)] · α3
here,
T1: An interval from the time when one hot water supply to the bathtub 31 is completed to the start of the next hot water supply, which can be set in advance. The unit is, for example, “minute”.
T2: The estimated required time required for one hot water supply to the bathtub 31, and the unit is, for example, “minute”. The time T2 varies depending on the thickness of the pipe and the like, but can be obtained in advance by a test or the like.
Q1: It is an exhaust heat recovery amount per unit time (for example, 1 minute) in the heat exchanger 24 for heat recovery, and can be obtained in advance by a test or the like.
t0, t2: Same as previously mentioned hot water supply temperature t0 and incoming water temperature t2.
α2: A value for adding a margin and a positive value larger than zero.
α3: a coefficient for adding a margin, a positive value greater than 1.

  If hot water supply temperature t0 is determined by any one of methods 1 and 2, the hot water supply temperature t0 is set to a temperature that is higher than a certain level by a certain level higher than the incoming water temperature t2 or the reference temperature t3. Therefore, a large amount of heat can be discharged from the hot water storage tank 20 when the hot water is discharged from the hot water storage tank 20. Further, if the hot water supply amount Q0 is determined based on either of the above-described formulas 1 and 2, the amount of exhaust heat (heat release amount) during the hot water treatment from the hot water storage tank 20 is converted into the heat in the heat exchanger 24 for heat recovery. It is possible to accurately prevent the heat storage amount of the hot water storage tank 20 from becoming full by making the amount more than the recovery amount.

Generally, in a hot water apparatus (including a cogeneration system) having a bath function (hot water filling, reheating, etc.) Hereinafter, the target pouring temperature) can be set individually by operating the operation switch 41 of the remote controller 4. When the hot water supply operation request due to opening of the front plug 30 and the pouring operation request to the bathtub 31 (including the “hot water treatment” in the present invention) occur simultaneously, the target hot water supply temperature to the front plug 30 The hot water supply operation is preferentially performed, and the start of the hot water supply operation at the target pouring temperature to the bathtub 31 is delayed until the hot water supply operation to the front plug 30 is completed, for example, the front plug 30 is closed. .
For this reason, when the hot water supply operation switch 41a is in an OFF state and non-heated water having a minimum operating flow rate or more is used in the tip plug 30, when the request for starting the hot water discharge process of the present invention occurs, the hot water supply operation switch 41a is The hot water supply operation at the target hot water supply temperature to the first plug 30 is forcibly turned on, and the start of the hot water discharge process at the target hot water supply temperature to the bathtub 31 ends the hot water supply operation to the first plug 30. Delayed until.
In this case, in claim 1 of the present invention, the hot water supply temperature is lowered so that the hot water supply temperature is lower than the target hot water supply temperature for the tip plug 30. In claim 4 of the present invention, the target hot water supply temperature for the bathtub 31 is set. On the other hand, the temperature change control during the hot water treatment is performed.

  The present invention is not limited to the contents of the above-described embodiment. The specific configuration of each part of the cogeneration system according to the present invention can be variously modified within the intended scope of the present invention.

  In the embodiment described above, the amount of heat stored in the hot water storage tank 20 in step S2 is greater than or equal to a predetermined value as a condition for forcibly executing the hot water discharge processing from the hot water storage tank 20 by switching the hot water supply operation switch 41a from the off state to the on state. In addition to the fact that the hot water supply operation switch in step S3 is turned off, the tip stopper in step S4 is opened and water is supplied to the tip stopper, and the target in step S5 Although it is a further condition that the hot water supply temperature is equal to or higher than a predetermined temperature (for example, 50 ° C.), the present invention is not limited to this. Both or one of the two conditions of steps S4 and S5 may be eliminated.

In the present invention, when the hot water supply operation switch is switched from the OFF state to the ON state in order to execute the hot water discharge process, if the process of lowering the subsequent hot water supply temperature below the target hot water supply temperature set before is executed. Although the process of lowering the hot water supply temperature does not always have to be performed in this way, it need only be executed when a certain condition is met. For example, the target hot water supply temperature is 38
When the temperature is set to ° C., it is not necessary to further lower the target hot water supply temperature. From the viewpoint of increasing the amount of heat release during the process of discharging hot water from the hot water storage tank, control such as raising the target hot water supply temperature from 38 ° C. to 40 ° C. may be appropriately performed. This will be understood from the process of determining the hot water supply temperature t0 by the methods 1 and 2 described above.

  When performing hot water discharge treatment from a hot water storage tank, it is preferable to send hot water to the bathtub so that the hot water can be used for bathing, but this is not limited to this, and there is a hot water storage alternative to the bathtub. The hot water may be sent to the hot water storage means. Moreover, although not preferable from the viewpoint of effective use of hot water, it may be led to a drain outlet in a bathroom, for example, to be drained. Even in this case, it is effective to reduce the amount of heat stored in the hot water storage tank and continue driving the power generation unit.

  The hot water treatment from the hot water storage tank intended by the present invention is useful for continuing the self-sustaining power generation of the power generation unit 10, but the present invention can also be applied during non-self-sustaining power generation. Even when the cogeneration system is operating with power supplied from an external power supply, the power generation unit 10 is driven without stopping the drive of the power generation unit 10 because the amount of heat stored in the hot water storage tank is full. It may be assumed that the user desires to continue. This is because, in order to meet such a demand, the hot water treatment intended by the present invention should not be limited at the time of independent power generation.

  The power generation section referred to in the present invention is not limited to a configuration in which a generator is rotated using a gas engine, and a configuration using, for example, a fuel cell can also be used. The definition of the ON state and the OFF state of the hot water operation switch in the present invention is as described above, and the ON state of the hot water operation switch is synonymous with the state in which the hot water operation permission mode is set, The OFF state of the operation switch is synonymous with the state in which the hot water supply operation stop mode is set.

C Cogeneration system 10 Power generation unit 20 Hot water storage tank 22 Control unit (control means)
24 Heat exchanger 30 for heat recovery Tip plug 31 Bathtub 41a Hot water supply operation switch

Claims (3)

A heat exchanger for heat recovery capable of recovering heat generated in the power generation unit and performing hot water heating,
A hot water storage tank capable of storing hot water heated using this heat exchanger,
Control means capable of executing operation control to adjust the hot water discharged from the hot water storage tank to a preset target hot water temperature and supply it to a desired hot water supply destination when the hot water supply operation switch is on;
With
The control means, when driving the power generation unit, when the heat storage amount of the hot water storage tank is equal to or greater than a predetermined amount, and at that time, a specific state in which the hot water supply operation switch is turned off occurs, By switching the hot water supply operation switch to the on state and then supplying hot water in the hot water storage tank to a bathtub or a predetermined place instead of the bathtub, it is possible to perform control to execute hot water discharge processing for reducing the amount of heat stored in the hot water storage tank. Is a cogeneration system,
The control means can determine whether hot water circulation has occurred in the hot water flow path for supplying heated or non-heated hot water to a desired hot water supply destination,
When the hot water supply operation switch is switched from the off state to the on state due to the occurrence of the specific state, if it is determined that hot water circulation has occurred in the hot water channel, the subsequent hot water temperature is set. If hot water temperature lowering control is performed to lower the target hot water temperature set before that, while hot water circulation is not determined to occur in the hot water channel, the hot water temperature lowering control is not performed. A cogeneration system, characterized in that it is configured. The cogeneration system according to claim 1,
The hot water supply temperature lowering control is configured to be executed when a target hot water temperature set before the occurrence of the specific state is equal to or higher than a predetermined temperature, and is not executed otherwise. The cogeneration system according to claim 1 or 2,
When the hot water treatment is performed, the amount of hot water discharged from the hot water storage tank and its temperature are set so that the amount of heat released from the hot water storage tank is equal to or greater than the amount of heat recovered by the heat exchanger for heat recovery. A cogeneration system that is configured to be controlled .

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