JPH07103499A - Circulation type hot water supplying apparatus - Google Patents

Abstract

PURPOSE:To prevent overshoot at the time of supplying hot water and delay of starting at the time of heating to circulate by storing an integral value feedback calculated by dividing to a circulating heating and hot water supplying as optimum integral value, and using it as a calculated value of a feedback calculated value of next time for a predetermined time. CONSTITUTION:A circulating heating judging unit 21 outputs a circulating signal when a water flow rate Q is detected by a water flow rate sensor and a water flow switch is so turned OFF as not to detect a water flow. An optimum integral value controller 29 adds a stored value X at the time of circulating to heat stored in an optimum integral value memory 28 to a feedback calculator 30. On the other hand, at the time of supplying hot water in which the circulating signal is not output, a stored hot water supply value Y is added to the calculator 30. The calculator 30 applies the stored values to a heat quantity deciding unit 43. After a predetermined time is elapsed from the start of controlling, a switch 27 is closed, a deviation of a hot water temperature TM from a set temperature TS is applied to the calculator 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention heats a water supply pipe and a heat exchanger connected to a hot water supply pipe by a heating section, and connects the end of the hot water supply pipe and the water supply pipe by a return pipe to form a circulation path. Then
The present invention relates to a circulation type hot water supply device that performs circulation heating for operating a circulation pump provided in this circulation path and hot water supply while the circulation pump is stopped.

[0002]

2. Description of the Related Art When controlling the heating amount of a heat exchanger during hot water supply, an integral calculation is performed on the deviation between the detected temperature of hot water passing through a hot water supply pipe and a set temperature to determine the required heating amount. The integrated value during hot water supply is stored as the optimum integrated value, the required heating amount is determined using the stored optimum integrated value at the beginning of the next hot water supply, and then the stored optimum integrated value is used as the initial value for calculation. A hot water supply device that determines the required heating amount is known.

Further, the end of the hot water supply pipe connected to the heat exchanger and the water supply pipe are connected by a return pipe to form a circulation path, and a circulation pump provided in this circulation path is operated to perform circulation heating. There is also known a circulating hot water supply device that supplies hot water by stopping the circulation pump.

[0004]

The technique for storing the integral value for the temperature deviation as the optimum integral value and determining the required heating amount by using the optimum integral value as the initial value for the next integral calculation is also described above. When applied to a circulation type hot water supply device, there are problems that an overshoot occurs during hot water supply and a rise is delayed during circulation heating.

That is, since the difference between the hot water supply temperature and the hot water supply temperature is small during circulation heating, the thermal efficiency decreases, and the optimum integrated value at that time increases, and this optimum integrated value becomes the initial value of the integral calculation during the next hot water supply. Then, the required heating amount becomes excessive. On the other hand, during hot water supply, the difference between the hot water supply temperature and the water supply temperature is large, so the thermal efficiency is higher than during circulation heating, and the optimum integrated value at that time is smaller, and this optimum integrated value becomes the initial value of the integral calculation during the next circulation heating. When the value is set, the required heating amount is insufficient.

However, if the optimum integrated value during circulation heating is used for hot water supply control, overshoot occurs, and if the optimum integrated value during hot water supply is used for circulation heating control, the rise is delayed.

The present invention has been made in order to solve the above problems. Even when the required heating amount is determined by using the optimum integral value as the initial value of the next integral calculation, the overshoot during hot water supply and the circulation heating An object of the present invention is to obtain a circulation type hot water supply device capable of surely preventing a delay in rising of the water.

[0008]

The present invention heats a heat exchanger connected to a water supply pipe and a hot water supply pipe by a heating unit, and
A hot water supply pipe is formed by connecting the hot water supply pipe and the water supply pipe with a return pipe to form a circulation path, and operating a circulation pump provided in the circulation path to perform circulation heating or to stop the hot water supply. In the circulating water heater that controls the heating unit according to the output of the feedback calculation unit that performs at least integral calculation for the deviation between the detected temperature of hot water passing through A circulating heating determination unit, an optimal integrated value storage unit that stores the integrated values of the feedback calculation unit during circulating heating and during hot water supply as optimal integrated values, and an optimal integrated value storage unit that corresponds to the determination result of the circulating heating determination unit. The optimum integrated value of the heating unit is selected instead of the output of the feedback calculation unit until a predetermined time elapses from the start of hot water supply or circulation heating. It is obtained by a optimum integration value control unit to provide control to.

Preferably, the optimum integrated value control unit outputs the output of the feedback calculation unit after a predetermined time has elapsed from the start of hot water supply or circulation heating as optimum integration values corresponding to the judgment result of the circulation heating judgment unit. The optimum integrated value storage unit is made to learn and store.

[0010]

According to the present invention, the integrated value of the feedback calculation unit is stored as the optimum integrated value separately for the circulation heating and the hot water supply, and the optimum integrated value corresponding to the next control is selected and the control is started from the start. Since it is used as the calculation value of the feedback calculation unit until a predetermined time elapses, it is possible to reliably prevent overshoot during hot water supply and delay in rising during circulation heating.

In this case, the output of the feedback calculation unit after a lapse of a predetermined time from the start of the control is stored as the optimum integrated value corresponding to the judgment result of the circulation heating judgment unit, so that the optimum value to be used for the next time or later can be obtained. The integrated value can be made more optimal.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is a schematic configuration diagram of an embodiment of the present invention, mainly including a water heater main body 1, a hot water tap 6 and a control unit 10.
It is composed of 0s.

The water heater main body 1 comprises a heat exchanger 4, a circulation pump 7, a gas burner 8, a proportional valve 10 and an opening / closing valve 11. The heat exchanger 4 is connected to the water supply pipe 2 and the hot water supply pipe 3. A hot water supply tap 6 is provided at the end of the hot water supply pipe 3,
The end of is connected to the water supply pipe 2 via the return pipe 5. As a result, a circulation path composed of the water supply pipe 2, the heat exchanger 4, the hot water supply pipe 3, the return pipe 5 and the water supply pipe 2 is formed. Return pipe 5
A circulation pump 7 that circulates hot and cold water in the circulation path in the middle of the
Is provided. The gas burner 8 is connected to a gas pipe 9, and a proportional valve 10 and an opening / closing valve 11 are provided in the middle of the gas pipe 9.

The control unit 100 controls the proportional valve 10 and the on-off valve 11. Therefore, the water flow switch 12 for detecting the water flow of the water supply pipe 2 on the upstream side as seen from the connection point of the return pipe 5
And a water amount sensor 13 for detecting the flow rate Q of the water supply pipe 2 on the downstream side.
A hot water temperature sensor 14 for detecting the hot water temperature T _C and a hot water temperature sensor 15 for detecting the hot water temperature T _M of the hot water supply pipe 3 are provided. The control unit 100 controls the proportional valve 10 and the opening / closing valve 11 based on these detection signals and the set temperature T _S of the temperature setting unit 16 that sets the hot water supply temperature. The control unit 100 also controls the circulation pump 7, but since it is not directly related to the present invention, its control line is omitted.

FIG. 1 is a block diagram showing a detailed structure of the control unit 100. In the figure, the circulation heating determination unit 21 outputs a circulation signal when the flow rate Q is detected by the water amount sensor 13 and the water flow switch 12 is in the off state in which no water flow is detected, and the subtractor 22 sets the set temperature T _S. Water temperature T for
The deviation of _C is calculated, and the feedforward calculation unit 23 determines the feedforward control amount FF based on this deviation and the flow rate Q.
Is calculated. The combustion necessity determination unit 24 determines whether or not combustion is required based on the flow rate Q and the feedforward control amount FF. Specifically, the flow rate Q is equal to or higher than the ignition flow rate and the feedforward control amount FF. Is a ignition value or more, a combustion request signal is output, the timer 25 starts operation in accordance with this combustion request signal, and the switch 27 is closed after a set time has elapsed. Subtractor 26
Calculates the deviation of the hot water supply temperature T _M with respect to the set temperature T _S , and the deviation is supplied to the feedback calculation unit 30 via the switch 27. The optimum integrated value storage unit 28 separately stores the circulating heating storage value X and the hot water supply value storage value Y, and the optimum integration value control unit 29 controls writing and reading of these storage values. . The feedback calculation unit 30 is a well-known proportional element 31, differential element 32 and integral element.
33, the output of each element is added to obtain the feedback control amount FB. The temperature coincidence determination unit 41 detects the coincidence between the set temperature T _S and the hot water supply temperature T _M , the timer 42 starts the operation according to the coincidence signal, and after the elapse of the set time, outputs the time-up signal to the optimum integral value control unit Give to 29. In response to the time-up signal, the optimum integrated value control unit 29 stores the integrated value at that time in the optimum integrated value storage unit 28 as the optimum integrated value. The heat amount determination unit 43 determines the heating amount based on the feedback control amount FB and the feedforward control amount FF, and the opening / closing valve drive unit 51 that constitutes the heating unit 50 intermittently controls the opening / closing valve 11 according to this heating amount. The proportional valve drive unit 52 controls the proportional valve 10 according to this heating amount.

The operation of the present embodiment configured as described above will be described below. The circulation pump 7 is stopped when hot water is supplied to open the hot water tap 6, and the circulation pump 7 is driven during circulation heating. Based on the output signals of the water flow switch 12 and the water amount sensor 13, the control unit 100 determines whether hot water is being supplied or circulation heating is being performed, and the water amount sensor 13, the water supply temperature sensor 14, and the hot water temperature sensor, respectively.
The required heating amount is determined based on the output signals of 15 and the temperature setting unit 16, and the proportional valve 10 and the opening / closing valve 11 are controlled.

In this case, the circulation heating determination unit 21 is a water amount sensor.
When the flow rate Q is detected by 13, and the water flow switch 12 is in the off state in which no water flow is detected, a circulating signal is output. When the circulating signal is output, the optimum integrated value control unit 29 adds the stored value X during circulation heating stored in the optimum integrated value storage unit 28 to the feedback calculation unit 30, and the hot water supply value during hot water supply when the circulating signal is not output. The stored value Y is added to the feedback calculation unit 30. The feedback calculation unit 30 adds these stored values to the heat amount determination unit 43 as the feedback control amount FB. On the other hand, the feedforward calculation unit 23 calculates the feedforward control amount FF based on the detected deviation between the feed water temperature T _C and the set temperature T _S , and the detected flow rate Q, and adds it to the heat amount determination unit 43. The heat quantity determination unit 43 calculates the required heat quantity from these control quantities. The open / close valve drive unit 51 intermittently controls the open / close valve 11 according to the required heating amount, and the proportional valve drive unit 52 controls the proportional valve 10.

When the flow rate Q is equal to or higher than the ignition flow rate and the feedforward control amount FF is equal to or higher than the ignition value, the combustion necessity determination unit 24 outputs a combustion request signal and activates the timer 25. When the time set by the timer 25 elapses and the time-up signal is output, that is, when a predetermined time elapses from the start of the control, the switch 27 is closed and the deviation of the hot water supply temperature T _{M from} the set temperature T _S. Minutes are added to the feedback calculation unit 30. The feedback calculation unit 30 calculates the feedback control amount FB by the PID calculation according to this deviation and gives it to the heat quantity determination unit 43.

During the control of the heating amount, the temperature coincidence determination unit 41
The match between the hot water supply temperature T _M and the set temperature T _S is detected by the timer, and the timer 42 operates while the match signal continues to be output. If the coincidence signal disappears before the set time of the timer 42 elapses, the timer 42 is reset. Therefore, the hot water supply temperature T _M and the set temperature T are set longer than the time set in the timer 42.
_{When the} state of coincidence with _S continues, the time-up signal is added to the optimum integrated value control unit 29. The optimum integrated value control unit 29 updates the stored value of the optimum integrated value storage unit 28 using the output of the feedback calculation unit 30 at this time as the optimum integrated value. That is, if circulation heating is in progress, the stored value X during circulation heating is updated,
If hot water is being supplied, the stored hot water value Y is updated. As a result, the learning storage of the optimum integrated value is performed.

FIG. 3 is a flow chart showing a processing procedure when a microcomputer is used as the control unit 100 and the function shown in FIG. Hereafter, according to this flowchart, neither circulation heating nor hot water supply is performed, so-called
The control operation from the standby will be described.

First, at step 101, it is judged whether combustion is possible or not by whether or not the conditions that the flow rate Q is equal to or higher than the ignition flow rate and the feedforward control amount FF is equal to or higher than the ignition value are satisfied. If it is not possible, end the process,
If combustion is possible, the process proceeds to step 102. Appropriate values are used for the ignition flow rate and the ignition value depending on whether hot water is being supplied or circulating heating is being performed. Then, in step 102, a timer for determining whether or not it is the initial stage of control is started.

In step 103, it is judged whether or not the circulation is in progress depending on whether or not the condition that the flow rate Q is detected and the water flow is not detected is satisfied.
In step 4, the stored value X during circulation heating stored in the optimum integrated value storage unit 28 is used as the feedback control amount FB. If hot water is not circulating, in step 105, the optimum integrated value is set as the feedback control amount FB. The hot water supply value stored value Y stored in the storage unit 28 is used.

In step 106, the feedforward control amount FF is calculated, then in step 107, the required heating amount is calculated based on the feedforward control amount FF and the feedback control amount FB, and in step 108, the required heating amount is made to correspond. The proportional valve is controlled and the on-off valve is intermittently controlled.

Next, in step 109, it is judged whether or not the initial time of control has elapsed depending on whether or not the timer described above outputs the time-up signal. If not, the processing of steps 106 to 109 is executed. The above steps are repeated, and when the time has elapsed, the process proceeds to step 110 and the subsequent steps.

In step 110, the stored feedback control amount FB is used as an initial value, PID calculation is executed for the deviation between the hot water supply temperature T _M and the set temperature T _S to calculate the feedback control amount FB, and In step 111, the feedforward control amount FF is calculated. Further, in step 112, the required heating amount is calculated based on the feedforward control amount FF and the feedback control amount FB, and in step 113, the proportional valve is controlled corresponding to the required heating amount and the on-off valve is intermittently controlled.

Next, at step 114, it is judged whether or not the operation is possible depending on whether or not the condition that the flow rate Q is equal to or higher than the ignition flow rate and the feedforward control amount FF is equal to or higher than the ignition value is satisfied. If the operation is not possible, the processing is terminated, and if the operation is possible, the processing of the learning storage routine from step 115 onward is performed.

Therefore, in step 115, it is judged whether or not the hot water supply temperature T _M and the set temperature T _S match, and if they match, it is judged in step 116 whether the constant temperature state has continued for a predetermined time or longer. It is determined whether the timer for checking is active or not, and if not, it is operated at step 117 and the process proceeds to step 118.

In step 118, it is judged whether or not this timer has output the time-up signal. If the time-up signal is not output, the process returns to step 115 and the subsequent steps, and when the time-up signal is output, step 119 is executed. Move to processing.

In step 119, it is determined whether or not the circulation is in progress depending on whether or not the condition that the flow rate Q is detected and the water flow is not detected is satisfied.
The stored value X during circulation heating stored in 0 is replaced with the current feedback control amount FB, and if hot water is not circulating, in step 121 the stored hot water value stored value Y is replaced with the current feedback control amount FB, Return to step 110.

By the above processing, the control shown in the functional block of FIG. 1 can be realized, whereby the overshoot at the time of hot water supply and the delay of the rising at the time of circulating heating can be reliably prevented, and , The optimum integrated value used after the next time can be made more optimal.

In the above embodiment, the feedback calculation unit having the proportional, integral, and derivative calculation elements is used, but the present invention is not limited to this, and at least integral calculation is performed. If so, it is possible to perform an operation similar to that described above.

[0032]

As is clear from the above description, even when the required heating amount is determined by using the optimum integrated value as the initial value of the next integral calculation, the overshoot at the time of hot water supply and the delay of the rising at the time of circulating heating are ensured. Can be prevented.

Further, the output of the feedback calculation unit after a lapse of a predetermined time from the start of the control is stored as an optimum integral value corresponding to the judgment result of the circulation heating judgment unit, so that the optimum integration to be used in the next time or later is stored. The value can be more optimal.

[Brief description of drawings]

FIG. 1 is a block diagram showing a detailed configuration of main elements of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the main elements of the embodiment of the present invention.

[Explanation of symbols]

 1 water heater main body 2 water supply pipe 3 hot water supply pipe 4 heat exchanger 5 return pipe 6 hot water tap 7 circulation pump 8 gas burner 10 proportional valve 11 on-off valve 21 circulation heating determination unit 23 feedforward calculation unit 24 combustion necessity determination unit 28 optimal integration Value storage unit 29 Optimal integrated value control unit 30 Feedback calculation unit 100 Control unit

Claims (2)

[Claims] 1. A heat exchanger that communicates with a water supply pipe and a hot water supply pipe is heated by a heating unit, and the hot water supply pipe and the water supply pipe are connected by a return pipe to form a circulation path. When performing circulation heating by operating the provided circulation pump, or stopping it to supply hot water, feedback that performs at least integral calculation for the deviation between the detected temperature of hot water passing through the hot water supply pipe and the set temperature In the circulating water heater that controls the heating unit according to the output of the calculation unit, the circulation heating determination unit that determines whether or not circulation heating is in progress, and the integrated value of the feedback calculation unit during circulation heating and hot water supply The optimum integrated value storage unit stores the optimum integrated value, and the optimum integrated value of the optimum integrated value storage unit corresponding to the determination result of the circulation heating determination unit is selected, and hot water supply or circulation is performed. A circulating hot water supply device, comprising: an optimum integral value control unit for providing the optimum integral value selected in place of the output of the feedback calculation unit to control the heating unit until a predetermined time has elapsed from the start of heat. apparatus. 2. The optimum integral value control unit associates the output of the feedback calculation unit after a lapse of a predetermined time from the start of hot water supply or circulation heating with the optimum integration value corresponding to the determination result of the circulation heating determination unit. The circulating hot water supply device according to claim 1, wherein the optimum integrated value storage unit learns and stores the value as a value.