JP3134542B2 - Hot water supply control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An object of the present invention is to provide a hot water supply control method for mixing hot water discharged through a heat exchanger with water by using a bypass to supply hot water at a predetermined hot water supply temperature.

[0002]

2. Description of the Related Art As a conventional hot water supply control apparatus of this kind, an apparatus described in Japanese Patent Application Laid-Open No. 3-186150 is provided. The apparatus includes a heating device, a heat exchanger, a control valve for controlling the amount of water in the heat exchanger, a bypass for bypassing a water passage to the heat exchanger, the heat exchanger outlet and the bypass passage. A tap water temperature detector provided downstream of a mixing section with the water, a water flow control valve provided in the bypass passage, a drive device for the water flow control valve, a tap water temperature setting section, a heating control section, and a water flow control section. A hot water supply control unit, which adjusts a heating amount of a heating device according to a deviation signal between the tap water temperature detector and the tap water temperature setting unit, and adjusts a mixing ratio by changing an opening degree of the water flow control valve according to the deviation signal. Hot water supply control device.

[0003]

However, in the above-mentioned conventional apparatus, hot water at a set hot water supply temperature is supplied.
Since both the heating control of the heating device and the opening control of the water flow control valve in the bypass path are adjusted, the two controls interfere with each other. There is a disadvantage that it takes a long time to adjust the temperature. Further, there is a disadvantage that the control device becomes complicated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a hot water supply control method which can easily and reliably supply hot water at a set hot water supply temperature by mixing water, and which has a simple and inexpensive structure. And

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned object, the present invention relates to a method of heating water from an inlet channel with an instantaneous heat exchanger to supply hot water to a hot water channel, and to connect a bypass from the water inlet channel to a hot water channel. A hot water supply control method in which water is mixed by connecting to a predetermined hot water supply temperature to perform hot water supply;
When the hot water supply temperature is set, the set hot water supply temperature T _QS , the incoming water temperature T _C, and the reference distribution ratio K _BKO in the bypass are used to calculate the hot water supply set temperature T _KS of the heat exchanger. The burner of the instantaneous heat exchanger is then burned under certain conditions so as to generate heat corresponding to _KS ,
After an additional starting hot water supply, the actual hot water temperature T _K and the set hot water supply temperature T _QS and the incoming water temperature T _C and the set hot water supply temperature T target distribution ratio K necessary for hot water supply hot water _QS from the moment the heat exchanger _BKS is always calculated and obtained by experiments in advance.
One-to-one correspondence with the distribution ratio stored as
The target distribution ratio from the relationship with the drive current value of the mixed water regulating valve.
Target distribution ratio corresponding driving current value _{I BKS} corresponding to K _BKS
Is selected from the table, and the drive corresponding to the target distribution ratio is selected.
The set hot water supply temperature T _QS and the actual hot water supply are compared with the current value I _BKS .
By adding the correction drive current I _H in accordance with the difference between the water temperature T _Q
A total driving output current I _OUT, 該全driving output current value I
_OUT to the mixed water regulating valve so that the bypass
The first feature is that only the water mixing regulating valve is controlled . In addition, the present invention provides, in addition to the first feature,
As the correction drive current value _{I H,} the actual and set hot water supply temperature _{T QS}
Instead of using a value corresponding to the difference between the hot water supply temperature _TQ and
According to the difference between the standard distribution rate K _BKS and the reference distribution rate K _BKO
The second feature is to use a value .

[0006]

According to the first feature of the present invention, when the hot water supply temperature is set and the hot water supply curn is opened, the set hot water supply temperature T is set.
Reference distribution ratio K in the _QS and the incoming water temperature _{T C} and the bypass
First, the set tap temperature T _KS of the instantaneous heat exchanger is calculated from _BKO . Then, the burner of the instantaneous heat exchanger is burned under certain conditions so as to generate heat corresponding to tapping at the set tapping temperature. The reality without matching set hot water temperature T _KS actual tapping temperature T _K is the calculation of the moment after the tapping has been initiated the heat exchanger, without controlling modify the combustion amount of the burners, Only the bypass water mixing control valve is controlled. The control calculates a target distribution ratio K _BKS required for hot water set hot water supply temperature T _QS from and incoming water temperature T _C the set hot water supply temperature T _QS is hot water at all times, it
Table corresponding target distribution ratio corresponding driving current value I _BKS to
The hot water supply temperature T
Correction drive current according to the difference between _QS and actual hot water supply temperature T _Q
Value _{I H} is added, the total driving output current _{I OUT} is-determination
It is. The control of the mixing valve is controlled by the total drive output current.
This is performed by passing the value _IOUT . Since the adjustment to the set hot water supply temperature uses only the bypass water mixing adjustment valve and does not change and adjust the combustion amount of the burner on the way, control by adjusting both the combustion and the water mixing amount as in the conventional case described above And the difficulty of adjustment to the predetermined set hot water supply temperature due to mutual interference is eliminated, and hot water supply at the set hot water supply temperature can be easily and accurately performed. Also, since there is no need for a means for changing and adjusting the burner combustion amount on the way, the necessary members and control mechanisms are not required, and the configuration of the apparatus can be made simple and inexpensive, for example, the number of microcomputer ports can be reduced. Can be. In addition, the target distribution selected from the table
Hot water supply temperature T _QS set for drive current value I _BKS corresponding to rate
Correction drive current value I corresponding to a difference between the actual hot-water supply temperature T _Q When
_By adding _H, the specified hot water supply temperature is more quickly
T _QS can be adjusted. The second aspect of the present invention
According to the feature, as the correction drive current value I _H, set hot water supply
A value corresponding to the difference between the temperature T _QS and the actual hot water supply temperature T _Q is used.
Instead of the target distribution K _BKS and the reference distribution K
By using a value corresponding to the difference between the _BKO, Fidoba Tsu
When using (T _QS -T _Q ) as the target,
You can reduce your instability.

[0007]

FIG. 1 is a diagram showing the overall configuration of a water heater in which the method of the present invention is carried out, and FIG. 2 is a diagram showing the relationship between the distribution ratio and the driving current value of the water mixing regulating valve corresponding to the distribution ratio one-to-one. FIG. 3 is a flowchart showing a control example.

In the water heater shown in FIG. 1, the water supplied to the water inlet 10 is heated by the instantaneous heat exchanger 20 and discharged to the hot water outlet 30. From the water inlet channel 10, a bypass 40 is connected to the hot water channel 30.
And are adapted to mix water. The inlet channel 10 is provided with an inlet temperature sensor 11 and an inlet flow sensor 12. Further, the instant heat exchanger 20 is provided with a burner 21. A tapping temperature sensor 31 is provided in the tapping path 30.
A hot-water supply temperature sensor 51 is provided in a hot-water supply path 50 downstream of a point 32 of the hot-water supply path 30 to which the bypass 40 is connected.
Is provided. Reference numeral 60 denotes a controller with a built-in microcomputer for controlling the entire water heater, which inputs information from the sensors 11, 12, 31, and 51 and a command from a remote controller (not shown), performs calculations in accordance with a predetermined program, and performs operations to the respective parts 21 and 41. Output a control signal.

Next, a method of controlling hot water supply by the controller 60 will be described with reference to FIGS. When a hot water supply curl (not shown) in the hot water supply path 50 is opened while the pilot flame is on (yes in S1), water is supplied through the water inlet path 10, and this water flow is detected by a water flow sensor (not shown). Then, the combustion of the burner 21 is started. At this time, the controller 60 determines the instantaneous heat exchanger 20 based on the set hot water supply temperature T _QS set by the user, the incoming water temperature T _C from the incoming water temperature sensor 11, and the reference distribution K _BKO in the bypass 40.
Calculating a set hot water temperature T _KS (S2). And allowed to feed forward combustion burners 21 in subsequent certain conditions to generate an amount of heat corresponding to the set hot water temperature T _KS of the heat exchanger 20 (S3). Bypass by the reference distribution ratio _KBKO
Assuming that the amount of water to the 40 side is Q _BO and the amount of water to the heat exchanger 20 side is Q _KO , the following equations 1 and 2 are established.

[0010]

[Number 1] _{T QS (Q BO + Q KO} ) = T C · Q BO + T KS · Q KO T QS: set hot water supply temperature T _C: incoming water temperature T _KS: setting of the heat exchanger 20 hot water temperature Q _BO: reference distribution The amount of water to the bypass 40 at the rate K _BKO Q _KO : The amount of water to the heat exchanger 20 at the reference distribution rate K _BKO

[0011]

[Number 2] _{K BKO = Q BO / Q KO} K BKO: reference distribution ratio Q _BO: water to the bypass 40 side of the reference distribution ratio K _BKO Q _KO: the heat exchanger 20 side of the reference distribution ratio K _BKO Amount of water

From the above equations (1) and (2), the set tapping temperature T _KS of the heat exchanger 20 is obtained by the following equation (3).

[0013]

Equation 3] _{T KS = T QS (1 +} K BKO) -T C · K BKO T KS: setting of the heat exchanger 20 hot water temperature T _QS: set hot water supply temperature T _C: incoming water temperature K _BKO: reference distribution ratio

When the set hot water temperature T _KS of the heat exchanger 20 is calculated, the required heat quantity of the instantaneous heat exchanger 20 is multiplied by the water quantity Q _KO. A command is issued from the controller 60 to a fuel supply adjusting means (not shown). Thus, the burner 21 is feed-forward controlled. This control amount is kept constant until the hot water supply ends thereafter, and is not adjusted in the middle. Even if the reference distribution ratio _KBKO is designed so that the water mixing control valve 41 always starts from a constant reference distribution ratio at the start of hot water supply, the water mixing adjustment valve 41 also stops the previous hot water supply. Even if it is designed so that the distribution ratio at the time of carrying over is carried over as it is, any of the water mixing control valves 41 may be used. In short, the reference distribution ratio _KBKO is the water mixing control valve at the start of hot water supply.
The distribution ratio of 41 is assumed.

When the burner 21 is burned as described above and hot water supply is started, the controller 60 then determines the actual hot water supply temperature T _Q detected by the hot water supply temperature sensor 51 as the set hot water supply temperature T.
_The actual tapping temperature T _K of the heat exchanger 20 detected by the tapping temperature sensor 31 is input so as to be _QS (S4), and the target distribution ratio _KBKS is calculated (S5). The target distribution ratio K _BKS is calculated from the following equations (4), (5) and (6).

[0016]

Equation 4] _{T QS (Q BS + Q KS} ) = T C · Q BS + T K · Q KS T QS: set hot water supply temperature T _C: incoming water temperature T _K: tapping of the heat exchanger 20 temperature Q _BS: target distribution ratio water Q _KS to the bypass 40 side in K _BKS: water to the heat exchanger 20 side of the reference distribution ratio K _BKO

[0017]

[ _Equation 5] K _BKS = Q _BS / Q _KS

[0018]

K _BKS = Q _BS / Q _KS = (T _K −T _QS ) / (T _QS −T _C ) K _BKS : Target distribution ratio T _K : Tap water temperature of heat exchanger 20 T _QS : Set hot water temperature T _C: incoming water temperature

When the target distribution ratio K _BKS is calculated as described above, the controller 60 then reads the mixing control valve 41 corresponding to the target distribution ratio K _BKS from a table stored in a built-in storage unit. The drive current value I _BKS of the drive section 42 is extracted (S6). The table stored in the storage unit built in the controller 60 obtains the relationship between each current value of the driving unit 42 and the distribution ratio as shown in FIG. It is obtained by memorizing it.

[0020] The further controller 60, various errors occurring during control, absorb deviations, for adding the correction according to the situation, calculates a correction drive current value I _H (S7), the correction driving current value I _H And the drive current value I corresponding to the target distribution ratio.
The total drive output current value I _{OUT of the} drive unit 42 is determined by summing with _BKS.
Is calculated (S8). The corrected drive current value I _H is a feedback value proportional to the difference between the set hot water supply temperature T _QS and the actual hot water supply temperature T _Q, and is calculated by the following equation (7). Further, the total drive output current value I _OUT is represented by _Expression 8.

[0021]

I _H = K _P (T _QS −T _Q ) + K _I · Σ (T _QS −T _Q ) I _H : Corrected drive current value K _P : Proportional constant K _I : Integral constant T _QS : Set hot water temperature T _Q : Actual hot water temperature

[0022]

I _OUT = I _BKS + I _H I _OUT : all drive output current values I _BKS : target distribution ratio corresponding drive current value I _H : correction drive current value

The [0023] above, the entire drive output current I _OUT is calculated, with at該全driving output current I _OUT, it commands the drive unit 42 to drive the mixing water adjustment valve 41 (S9).
Until the hot water supply curn is closed, S4 to S10 are repeated at a fixed short time interval.

In the above example, the corrected drive current value I _H is given by
(Set hot water supply temperature T _{QS −actual} hot water supply temperature T)
_Q ) Feedback is applied to the temperature deviation. However, in this case, (T _QS -T _Q ) is the following equation using the set hot water supply temperature T _QS , the target distribution rate K _{BKS, the} current distribution rate K _BK , the heat exchanger outlet temperature T _K , and the inlet water temperature T _C. 9.

[0025]

T _QS -T _Q = (K _BK -K _BKS ) (T _K -T _C ) / (1 + K _BKS ) (1 + K _BK )

From equation (9), the amount of change of (T _QS -T _Q ) varies depending on the values of the outlet temperature T _K , incoming water temperature T _C , target distribution rate K _BKS , and current distribution rate K _BK of the heat exchanger 20. Therefore, as a feedback target (T _QS −
Using T _Q ) may result in unstable control depending on the above values.

Therefore, a feedback value proportional to the difference between the target distribution ratio K _BKS and the current distribution ratio K _BK may be used as another corrected drive current value I _H. The corrected drive current value I _{H in} this case is calculated by the following equation (10).

[0028]

## _EQU10 ## I _H = K _P (K _BKS −K _BK ) + K _{I I} (K
_BKS -K _BK) I _H: correction drive current value K _P: proportional constant K _I: integral constant K _BKS: target distribution ratio _{= (T K -T QS) /} (T QS -T C) K BK: Current distribution Rate = (T _K −T _Q ) / (T _Q −
T _C )

By using the corrected drive current value I _H calculated by the equation (10), more stable control can be achieved.

Further, as a method for increasing the stability of the control, the heat exchanger in the target distribution K _BKS in the equation (10) is used.
It is possible to compensate for the advance of the hot water temperature T _K of the heat exchanger 20, the delay of the hot water temperature T _K of the heat exchanger 20 during the current distribution ratio K _BK , and the advance of the hot water supply temperature T _Q. That is, in this case, the target distribution ratio K _BKS and the current distribution ratio K _BK are calculated by, for example, the following equation (11).
Can be represented by

[0031]

K _BKS = (Time constant correction T _K -T _QS ) / (T _QS -T _C ) K _BK = (T _K several hundred milliseconds earlier-Time constant correction T _Q ) / (Time constant correction T _Q- T _C ) T _K : Outlet temperature of heat exchanger T _QS : Set hot water supply temperature T _C : Inlet water temperature

[0032]

According to the hot water supply control method according to the first aspect of the present invention, when the hot water supply temperature is set, a heat quantity corresponding to the set tapping temperature T _KS is generated. After that, the burner is burned under a certain condition, and after the hot water supply is started, the required target distribution ratio K _BKS is always calculated, and only the bypass water mixing regulating valve is controlled so as to reach the calculated target distribution ratio _KBSK. Therefore, the combustion amount of the burner is not changed and adjusted in the middle, so that the control is complicated by adjusting both the combustion and the mixed water amount in the conventional manner, and the predetermined hot water supply temperature due to mutual interference is not controlled. The difficulty of adjustment can be eliminated, and hot water supply at the set hot water supply temperature can be easily and accurately performed. Needless to say, there is no need for a means for changing and adjusting the burner combustion amount in the middle, so that members and a control mechanism necessary for the change are unnecessary, and the number of microcomputer ports can be reduced. be able to. In addition, the control of the water mixing regulating valve is performed by correcting the drive current value I _BKS corresponding to the target distribution ratio selected from the table with the corrected drive current value corresponding to the difference between the set hot water supply temperature T _QS and the actual hot water supply temperature T _Q. is performed by I _H is the total drive output current I _OUT applied more quickly, the error can be adjusted to less accurate set hot water supply temperature T _QS of deviation.
According to the second aspect of the present invention, instead of using the value corresponding to the difference between the set hot water supply temperature T _QS and the actual hot water supply temperature T _Q as the correction drive current value I _H , the target distribution ratio K _BKS and the reference distribution By using a value corresponding to the difference between the rate K _BKO and the difference between the set hot water supply temperature T _QS and the actual hot water supply temperature T _Q as a feedback target, it is possible to reduce the instability of control that occurs.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a water heater in which a method of the present invention is performed.

FIG. 2 is a diagram showing a relationship between a distribution ratio and a driving current value of a water mixing regulating valve corresponding to the distribution ratio on a one-to-one basis.

FIG. 3 is a flowchart showing a control example according to the method of the present invention.

[Explanation of symbols]

 10 Inlet channel 11 Inlet temperature sensor 20 Instantaneous heat exchanger 21 Burner 30 Outlet channel 31 Outlet temperature sensor 40 Bypass 41 Water mixing regulating valve 42 Drive unit 50 Hot water channel 51 Hot water temperature sensor 60 Controller

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Yoshida 32, Akashi-cho, Chuo-ku, Kobe-shi, Hyogo Noritsu Co., Ltd. (56) References JP-A-4-76350 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F24H 1/10 302

Claims (2)

(57) [Claims] 1. A system according to claim 1, wherein the water from the water inlet is heated by an instantaneous heat exchanger to supply the hot water to the hot water outlet, and a bypass from the water inlet is connected to the hot water outlet to mix the water. A hot water supply control method that adjusts the hot water supply.
When the hot water supply temperature is set, the set hot water supply temperature T _QS , the incoming water temperature T _C, and the reference distribution ratio K _BKO in the bypass are used to calculate the hot water supply set temperature T _KS of the heat exchanger. The burner of the instantaneous heat exchanger is then burned under certain conditions so as to generate heat corresponding to _KS ,
After an additional starting hot water supply, the actual hot water temperature T _K and the set hot water supply temperature T _QS and the incoming water temperature T _C and the set hot water supply temperature T target distribution ratio K necessary for hot water supply hot water _QS from the moment the heat exchanger _BKS is always calculated and obtained by experiments in advance.
One-to-one correspondence with the distribution ratio stored as
The target distribution ratio from the relationship with the drive current value of the mixed water regulating valve.
Target distribution ratio corresponding driving current value _{I BKS} corresponding to K _BKS
Is selected from the table, and the drive corresponding to the target distribution ratio is selected.
The set hot water supply temperature T _QS and the actual hot water supply are compared with the current value I _BKS .
By adding the correction drive current I _H in accordance with the difference between the water temperature T _Q
A total driving output current I _OUT, 該全driving output current value I
_OUT to the mixed water regulating valve so that the bypass
A hot water supply control method, wherein only a water mixing regulating valve is controlled . As wherein the correction drive current value I _H, set hot water supply temperature
Using a value corresponding to the difference between the degree T _QS and the actual hot water supply temperature T _Q
Instead of the target distribution K _BKS and the reference distribution K _BKO
The hot water supply control method according to claim 1, wherein a value corresponding to a difference between the hot water supply and the hot water supply is used .