JPH0237212A - Temperature controlling device of hot water supplier - Google Patents

Abstract

PURPOSE:To make it possible to quickly deliver hot water with the set temperature by a method wherein the temperature of a heat exchanger is calculated on the basis of the heat capacity of the heat exchanger and the temperature of hot water flowing out of the heat exchanger and the heating amount to be given to the heat exchanger is corrected. CONSTITUTION:When the thermal equilibrium of a heat exchanger 32 is attained after the continuation of supply of hot water corresponding to the set temperature of a controller 47, the temperature of the heat exchanger 32 is calculated as its initial value on the basis of the precalculated heat capacity of the heat exchanger 32 and the temperature of hot water flowing out of the heat exchanger 32 detected by a heat exchange thermistor 37. After that, when the flow rate is changed by a user, the reference heating amount is changed accordingly. As a result, a correcting unit 44 calculates the corrected combustion rate of a burner 10 and its corrected time on the basis of the initial value of the temperature of the heat exchanger 32 and the changed reference heating amount. Further a combustion control unit 45 controls the burner 10 according to the corrected heating amount. As a result, the combustion rate of the burner 10 is changed in a short time and consequently the temperature of supplying hot water flowing out of the heat exchanger 32 can be made equal to a certain temperature corresponding to the set temperature.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a water heater that controls the temperature of hot water flowing out of a heat exchanger to a predetermined temperature by controlling a heating means that heats a heat exchanger. Regarding a control device.

[Prior art] In water heaters, heating means such as burners and electric heaters are feedforward controlled according to the incoming water temperature, incoming water amount, and set temperature so that the hot water outlet temperature can be obtained according to the needs of the user. .

[Problem to be solved by the invention v1] However, even if the combustion l is immediately changed in response to a change in the amount of water input or a change in the set temperature,
The heat exchanger through which heated water passes has a residual amount of heat due to its heat capacity based on its material, shape, size, etc.
The actual amount of heating does not reach the set temperature until time has elapsed for the heat exchanger to reach thermal equilibrium, resulting in excessive heating or insufficient heating. Therefore, after such a change, there is a problem in that it takes time until hot water is supplied at the set temperature.

SUMMARY OF THE INVENTION An object of the present invention is to provide an efficient temperature control device that can promptly supply hot water according to the set temperature even when the amount of water or the set temperature is changed.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides heating to the heat exchanger based on the temperature of water flowing into the heat exchanger and the flow rate of water passing through the heat exchanger. In the temperature control device for a water heater, the temperature control device includes a control means for controlling the amount of hot water flowing out from the heat exchanger to a set temperature, the control means controlling the heat capacity of the heat exchanger and the temperature of the hot water flowing out from the heat exchanger. Calculating means for calculating the temperature of the heat exchanger 11!13 based on the temperature of the hot water flowing out, and correcting the amount of heating to the heat exchanger based on the temperature of the heat exchanger calculated by the calculating means. The technical means is to include heating amount correction means.

Effects and Effects of the Invention] In the present invention, the amount of heating to the heat exchanger is controlled based on the inflow temperature and inflow water to the heat exchanger, and hot water is supplied at a set temperature. In this heating amount control, the temperature of the C heat exchanger is calculated by the calculation means based on the heat capacity of the heat exchanger and the temperature of hot water flowing out from the heat exchanger, and heating is performed based on the calculated temperature of the heat exchanger. Therefore, if the inflow temperature or amount of water changes, or if the set temperature changes, the heating amount is corrected based on the heat exchanger temperature at the time of the change, so the heat The hot water temperature stored in the exchanger is rarely affected by the hot water temperature, and there is no overheating or underheating caused by the heat exchanger, so hot water is quickly tapped at the set temperature.

[Example] Next, the present invention will be explained based on embodiments shown in the drawings.

The gas water heater of this embodiment, which is schematically shown in FIG. 2, has a combustor 1
0, a fuel pipe 20, a water pipe 30, and a control device 40.

The combustor 10 is a heating means of the present invention, and consists of a burner plate 11 provided in the water heater case 1 and a blower 12 that supplies combustion air. All-in-one combustion is performed using only the combustion air supplied by the combustion chamber, and the combustion gas is discharged from an exhaust port (not shown).

A sparker 14 of an ignition device, a flame rod 15 for flame detection, and a thermocouple 16 are provided above near the burner plate 11, respectively.

The fuel pipe 20 is for supplying fuel gas to the nozzle 13, and in order from the flow side, there are a main solenoid valve 21 and a main solenoid valve 22.
However, proportional valves 23 for adjusting the fuel supply 1 to the burner plate 11 are each provided, and the fuel pipes 20 are branched downstream of the proportional valves 23, and one of the branched fuel pipes 20 is connected to a fuel pipe 20 to cut off the fuel. Switching solenoid valve 2 for adjusting the combustion amount
4 is provided, and the other is provided with an orifice 25 for restricting the amount of fuel supplied to the burner plate 11.

The wood pipe 30 consists of a supply pipe 31 and a hot water supply pipe 31a connected to a water supply source and a hot water supply port (not shown), respectively, and a heat exchanger 32 and a bypass pipe 32a that communicate these, and the water supplied from the supply pipe 31 is Part of is heat exchange 1ah
32, the remaining portion passes through a bypass pipe 32a and is guided to the hot water supply pipe 31a, and a bypass valve 33 is provided at the junction with the heat exchanger 2; 32 and the bypass pipe 32a.
The water heated by the Fe2 heat exchanger 32 and the water guided without being heated by the bypass pipe 32a are mixed by appropriately adjusting the ratio.

On the other hand, the supply pipe 31 is equipped with a water flow control valve 34, a water flow sensor 35, and a large water temperature thermistor 36 from upstream, a heat exchange thermistor 37 is installed downstream of the heat exchanger 32, and a hot water outlet temperature thermistor 38 is installed in the hot water supply pipe 31a. Each is equipped.

The bypass valve 33 and the water flow control valve 34 are each driven by a geared motor provided therein, and a potentiometer is provided to detect the opening degree thereof, and the water flow sensor 35 is rotated by the water flow passing through the supply pipe 31. The number of pulse signals corresponding to the rotation speed of an impeller (not shown) is output.

The control device 40 is composed of a microcomputer and a drive circuit, and the microcomputer has, as shown in FIG. Calculation section 43, M1 main section 44, combustion control section 45, water amount control section 46
In addition, the control unit W40 includes a controller 47 operated by another user.

The sequence control unit 41 performs ignition operation in a predetermined sequence based on a water flow signal from the water flow sensor 35 and an operation signal from the controller 47 to start combustion, and also performs a preset ignition operation in the event of abnormal combustion, insufficient capacity, etc. If combustion occurs under such conditions, the operation of the entire combustor 10 and the fuel supply are stopped.

The reference heating amount determining unit 42 determines the reference heating amount FFn at time n as feedforward control based on the set temperature set by the controller 47, the large water temperature thermistor 36, and the signals from the water flow sensor 35.

Here, the reference heating amount F F n is the set temperature Tse [
, inlet water temperature Ti, large inlet water amount, thermal efficiency erf, F F
It is determined by n = (Tset - Tin) xW/eff.

The heat amount calculation unit 43 calculates the heat amount of the heat exchanger 32 based on the temperature detected by the heat exchange thermistor 37 when the combustion amount capacity control is started after a predetermined time has elapsed after the start of combustion. This is the initial value of the temperature of the exchanger 32.

Here, the fictive temperature Bn of the heat exchanger 32 at time n
The initial value of B. is calculated as Bo ``e Improves temperature characteristics.

The correction section 44 is a functional section for correcting the combustion amount of the combustor 10 based on the calculation result of the heat amount calculation section 43.

Here, the reference heating amount FF determined by the reference heating amount determination unit 42 is
The initial value B of the temperature of the heat exchanger 32 is calculated by monitoring the amount of change in n. The temperature of the heat exchanger 32 is determined based on the change gradient of the reference heating amount FFn for a predetermined unit time Δt (for example, 0.5 seconds)
In the cycle, the fictive temperature Bn of the heat exchanger 332 at time 11
[”C], B n =-A n (Bn-1-An)
Find it sequentially using xb. Here, b is a time constant, and
The steady-state fictive temperature An [° C.] of the heat exchanger 32 is determined by the reference heating amount FFn as A n = c X FF n 10d.

Here, both c and d are constants.

Furthermore, based on the steady-state fictive temperature An of the heat exchanger 332 and the fictive temperature Bn of the heat exchanger 32 at time n,
The transient heat transfer bone Kn at time n in the unsteady state is calculated as Kn=dX (An-Bn-1), and the corrected combustion amount of the combustor 10 is determined using this transient heat transfer bone Kn as a correction value, The period during which the transient thermal movement bone Kn is calculated is defined as the correction time.

Therefore, when the heat exchanger 32 is in a steady state at a fictive temperature An, for example, when the amount of water entering decreases, the fictive temperature Bn of the heat exchanger 32 at time n undergoes a quadratic change and gradually changes as shown in FIG. As the steady state fictive temperature Br++ approaches, the transient thermal transfer bone Kn gradually decreases as shown in FIG.

The combustion control unit 45 controls the blower 12, the proportional valve 23, and the switching solenoid valve 24 of the combustor 10 according to the combustion amount determined by the reference heating amount determination unit 42 and corrected by the correction unit 44.
control. Here, as mentioned above, since the correction unit 44 corrects the combustion l, if the substitute changes the amount of hot water supply or changes the set temperature, and the combustion amount needs to be changed accordingly, , heat exchanger 3 before change
Based on the excess or insufficient heat accumulated in 2.
Since the new combustion amount and its output time are determined, the combustion amount will not be excessive or insufficient, and the temperature of the hot water flowing out from the heat exchanger 32 can be changed quickly.

Further, the air-fuel ratio is corrected and controlled based on the output of the thermocouple 16.

The water amount control section 46 controls the water amount control valve 34 according to the combustion amount determined by the base heating amount determination section 42, and also controls the bypass valve 33 based on the detection signal of the hot water temperature thermistor 38.

The controller 47 starts the operation of the water heater and sets the hot water temperature according to the user's purpose. In addition, a liquid crystal display section for displaying the set temperature and a combustor 1
A combustion lamp is provided to indicate 0 combustion in progress to inform the user of the operating status.

In addition, the control device 40 also performs feedback control based on the detection signal of the heat exchange thermistor 37, and when the temperature of the hot water flowing out from the heat exchanger 32 reaches a predetermined condition, the combustion amount of the combustor 10 is corrected. be done.

The gas water heater having the above configuration operates as follows.

When the operating sound is set by setting the hot water temperature with the controller 47, turning on the operation switch, and operating a faucet (not shown), ignition is performed in a predetermined sequence, combustion starts in the combustor 10, and hot water flows out from the hot water supply port (not shown). .

When a predetermined period of time has elapsed, combustion amount control according to the set temperature of the controller 47 is started from 3' ftA at the initial stage of ignition, and the base wall heating amount is determined based on the inlet water temperature, the amount of inlet water, and the set temperature.

Then, the blower 12 is controlled according to the amount of heating, and combustion air corresponding to the amount of heating is supplied, and the rotation speed of the blower 12 is detected, and current is applied to the proportional valve 23 according to the detected rotation speed. Power is applied.

Further, the water supplied from the supply pipe 31 is divided into the heat exchanger 32 and the bypass pipe 32a and flows into the heat exchanger 32 and the bypass pipe 32a.
The water that has passed through a is mixed at a bypass valve 33 with its ratio adjusted, and then hot water is supplied.

When the hot water supply continues and heat balance of the heat exchanger 32 is achieved, the outflow temperature from the heat exchanger 32 is detected by the heat exchange thermistor 37, and the temperature and the pre-calculated heat exchanger FIAh3 are detected.
The temperature of the heat exchanger 32 is calculated based on the heat capacity of No. 2, and is set as an initial value.

Thereafter, as shown in FIG. 3, when the flow rate is changed from ■1 to ■2 by the user at time t1, the standard heating amount is changed accordingly to q as shown in FIG.

will be changed from 9□. Then, the correction unit 44 calculates the corrected combustion amount and correction time of the combustor 10 based on the initial value of the temperature of the heat exchanger 32 and the changed reference heating amount,
The combustion control unit 45 controls the combustor 10 according to the corrected heating amount.

As a result, the combustion amount of the combustor 10 is Q as shown in FIG.
The combustion amount is changed from 1 to Ql in a short time, and then the combustion amount is gradually changed from Ql to Q in accordance with the correct time of the correction section 44. Therefore, the temperature of the hot water flowing out from the C1 heat exchanger 32 does not change significantly, as shown in FIG. 5, and remains a substantially constant temperature according to the set temperature.

Furthermore, at time t2, the hot water supply amount is changed again and the flow rate becomes ■,
When the reference heating amount is changed to q, the combustion amount of the combustor 10 is similarly changed from Ql to Q4 in a short time, and then gradually changed to Q. As a result, the outflow temperature from the heat exchanger 32 can be set to a temperature corresponding to the set temperature.

As described above, according to the present invention, when the amount of hot water supplied is changed by the user and the amount of combustion is changed, the amount of combustion in the combustor is corrected based on the temperature of the heat exchanger, so that excessive Hot water can be supplied according to the set temperature without being overheated or underheated.

In this embodiment, a case has been described in which the set temperature is constant and the hot water supply amount is changed, but if the flow 1 is constant,
Even if the set temperature is changed, if the combustion amount is changed accordingly, the combustion amount will be corrected in the same way, so the hot water temperature should be quickly adjusted to the newly set temperature. Can be done.

In the above embodiments, a gas water heater using a full-air combustion type burner was shown, but heating means such as a Bunsen burner, an oil burner, or an electric heater may be used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the functional configuration of a control device for a gas water heater according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing the gas water heater of this embodiment, and FIGS. 3 to 5 are diagrams for explaining the operation of this embodiment. Figure 3 is a timing chart showing changes in hot water supply flow rate and reference heating amount in feedforward control, and Figure 4 is a timing chart showing changes in the reference heating amount in the combustor of this embodiment. Fig. 5 is a timing chart showing changes in the hot water supply temperature, Fig. 6 is a characteristic chart showing changes in the fictive temperature Bn of the heat exchanger, and Fig. 7 is a timing chart showing changes in the fictive temperature Bn of the heat exchanger. FIG. 3 is a characteristic diagram showing changes. In the figure, 40...control device (control means), 43...calorific value calculation section (calculation means), 44...correction section (heating amount correction means) 6

Claims (1)

[Scope of Claims] 1) Controlling the amount of heating to the heat exchanger based on the temperature of water flowing into the heat exchanger and the flow rate of water passing through the heat exchanger, and controlling the amount of heat that flows out from the heat exchanger. In a temperature control device for a water heater, the temperature control device includes a control means for adjusting the temperature of the hot water to a set temperature, wherein the control means adjusts the temperature of the heat exchanger based on the heat capacity of the heat exchanger and the temperature of the hot water flowing out from the heat exchanger. A water heater comprising a calculation means for calculating temperature, and a heating amount correction means for correcting the amount of heating to the heat exchanger based on the temperature of the heat exchanger calculated by the calculation means. Temperature control device.