JPH01150741A - Control device for feed hot water temperature of hot water feeder - Google Patents

Abstract

PURPOSE:To improve water amount precision and to prevent lowering of a hot water temperature, by providing a feedback control means to control a burner combustion amount, a feed water amount set means to determine a capacity feed water amount, a water amount control means to control a feed water amount by means of a water amount control valve, and a water amount correcting means to correct an error of a capacity feed water amount value. CONSTITUTION:A feedback control means 12 is formed by a PID (proportion, integration, differentiation) control rule, and controls a fuel regulator 8 so that a temperature deviation amount TER between a set temperature TS and a feed hot water temperature TO is reduced to zero. A feed water amount set means 13 is adapted to determine a capacity water amount FLmax to a maximum hot water feed capacity QGmax: a difference between TS and a feed water temperature Ti produces a heating increase temperature Tup, and QGmax is divided by Tup to determine FLmax. A water amount control means 14 compares the FLmax determined by the feed water amount means 13 with an actual feed water amount FL value to regulate a water amount control valve 6. When temperature is not increased to TS even if a feed water amount is regulated by the means 14, a water amount correcting means 15 corrects the FLmax value, TER is subtracted from Tup, a result is multiplied by FL, a result is updated to a true value QGmax by which TS is produced at an actual flow rate FL, and the FLmax is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hot water outlet temperature control device for controlling the amount of water supplied to a water heater.

Conventional technology Conventional control devices of this type adjust the combustion amount (e.g. gas proportional control valve) so that the hot water temperature reaches the set temperature, but if a heat load exceeding the maximum capacity of the water heater is required. To prevent this, a water flow control valve is installed that automatically reduces the amount of water supplied to the heat exchanger when the heat load demand exceeds the maximum capacity. The control valve determines the required heat load from the water supply temperature, set temperature, etc., determines whether the required heat load exceeds the maximum capacity, and adjusts the water flow control valve. (For example, Utility Model No. 62-1201
(No. 54 Publication) Problems to be Solved by the Invention However, with the above configuration, there were problems with control accuracy such as errors in the calculated required heat load due to fluctuations in thermal efficiency, etc., and a decrease in the maximum capacity of the water heater due to excessive throttling. .

The present invention solves such conventional problems and aims to correct water flow control errors.

Means for Solving the Problems In order to solve the above problems, the temperature control device for a water heater of the present invention controls the burner combustion amount according to the temperature deviation amount between the outlet temperature of the heat exchanger and the set temperature. a feedback control means, a water supply amount setting means for determining a heating temperature from the temperature of the water supply flowing into the heat exchanger and a set temperature, and calculating a capacity water supply amount by dividing the maximum capacity heat amount of the water heater by the heating temperature; A water flow rate control means for controlling the water supply amount using a water flow rate control valve based on the capacity water flow value of the setting means, and when the burner is at maximum combustion, a temperature deviation amount of the feedback control means, a subtracted value of the heating temperature, and a multiplication value of the water supply amount. The system is equipped with a water amount correction means for correcting an error in the capacity water supply amount value.

Function The present invention can improve water flow control accuracy and prevent a drop in hot water temperature due to insufficient throttling, etc., by the above-described configuration.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 is a block diagram of hot water temperature control according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a water heater.

In FIG. 2, 1 is a heat exchanger, 2 is a hot water tap, and 3 is a burner. In the water supply channel of the heat exchanger 1, there are provided a water supply temperature sensor 4 for detecting the water supply temperature, a water flow rate sensor 5 for detecting the water supply amount, a water flow control valve 6 for regulating the water supply amount, and a water supply water temperature sensor 4 for detecting the water supply temperature. A hot water temperature detector 7 is provided to detect the hot water temperature. Reference numeral 8 denotes a combustion amount regulator that adjusts the combustion amount of the burner 3, and is, for example, a proportional control valve. 9 is a solenoid valve that turns on and off the fuel to the burner 3; 1o is a water heater controller that constitutes a hot water outlet temperature control block shown in FIG. 1; 11 is a temperature setting device for setting the hot water temperature.

Next, the operation of the controller 1o will be explained using the first factor.

Feedback control means 12 provided to set the hot water temperature to the set temperature is configured using a general PID (proportional, integral, differential) control law, and is configured to adjust the set temperature T set by the temperature setting device 11.
Temperature deviation amount TER between s and outlet hot water temperature 'ro of heat exchanger 1 =
The combustion amount of the burner 3 is adjusted by controlling the fuel regulator 8 so as to eliminate Ts To. The temperature deviation amount TER becomes zero when the hot water temperature T0 reaches the set temperature Ts.

Next, the configuration of water flow control will be explained.

Water amount control is comprised of water supply amount setting means 13, water amount control means 14, and water amount correction means 15.

The water supply amount setting means 13 determines the maximum hot water supply capacity QGma of the water heater.
The capacity water amount FLm&X for x, that is, the maximum water amount value at which the set temperature Ts can be obtained is determined.

The capacity water amount I'L'max is obtained by calculating the heating increase temperature Tup from the feed water temperature T1 detected by the feed water temperature sensor 4 and the set temperature Ts set by the temperature setting device 11 using the following formula Tup=
TS-T1 Next, the capacity water amount FLmax is determined from the maximum hot water supply capacity QGmaz of the above-mentioned water heater and the heating rise temperature Tup.

FLmax = QGmax / Tup Figure 3 shows these relationships graphically, and the horizontal axis shows the heating rise temperature T.
The capacity water amount FLmax is shown with up as the vertical axis.

Therefore, the capacity water amount FLma corresponding to the heating increase temperature Tup
If the water heater is not used within X, the hot water temperature will drop.

The water flow rate control means 14 compares the capacity water flow rate FLmax value obtained by the water supply amount setting means 13 with the value of the water supply amount FL value actually flowing into the heat exchanger 1 detected by the water flow rate sensor 5, and controls the water flow rate control means 14. 6.

That is, when FLmax≧FL, the valve opening degree of the water flow control valve 6 is set to FL. When ≦FL, the valve opening degree of the water flow control valve 6 is adjusted to a small value.

The actual water supply amount FL is determined by the user adjusting the hot water tap 2.
There is no problem as long as it is used within the capacity water amount FLm'abX.

Next, the water amount correction means 15 will be explained.

The water amount correction means 16 corrects the capacity water amount FLmax value when the water supply amount FL exceeds the capacity water amount FLmax and the set temperature Ts has not been reached even though the water amount control means 14 has adjusted the water supply amount. It is something.

At this time, burner 3 is at maximum combustion, but the outlet temperature is T. has not reached the set temperature Ts, the temperature deviation amount TΣR constituting the feedback control means 12 has not reached the set temperature Ts.
This leaves an insufficient temperature for s.

Therefore, it is necessary to further reduce the water supply amount FL.

In order to reduce the water supply amount FL, the capacity water amount FL111aX determined by the water supply amount setting means 13 is changed.

The water amount correction means 15 calculates the maximum hot water supply capacity QGmaX of the water heater from the current flow rate value FL and the heating increase temperature value Tup,
Update the initially set QG□8 value.

At this time, the temperature deviation amount TE from the heating increase temperature value Tup
By subtracting R, the maximum hot water supply capacity qGmax is determined by the following formula.

QGzzz = FL (T11p-TER) That is, the current flow rate value FL is updated to the true maximum hot water supply capacity QGmax value that allows the set temperature Ts to be obtained.

Effects of the Invention As described above, the hot water temperature control device of the present invention provides the following effects.

(1) Since the water amount correction means is provided, it is possible to prevent a drop in the outlet temperature due to insufficient throttling of the water supply amount, and the water amount control accuracy is improved. It can also absorb errors in thermal efficiency and various sensors.

(2) Since the capacity water amount is determined from the maximum capacity of the water heater, it can quickly respond to changes in the set temperature and reduce the drop in hot water temperature.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram of a hot water temperature control device for a water heater that is an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the water heater.
FIG. 3 is a water heater capacity water flow characteristic diagram. 1...Heat exchanger, 3...Burner, 4.
... Water supply temperature sensor, 5 ... Water flow rate sensor, 6 ... Water flow control valve, 7 ... Hot water temperature sensor, 8 ... Fuel Adjuster, 11...
・Temperature setting device, 12... Feedback control means, 13... Water supply amount setting means, 14...
- Water amount control means, 15...Water amount correction means. Name of agent: Patent attorney Toshio Nakao and one other attorney
--＃Eigabashi [Abroiled 8-゛-Konryo Sakaki vinegar roll f3-Clam water! Minesada ten erasing R search rules

Claims (1)

[Claims] A heat exchanger, a burner that heats the heat exchanger, a combustion amount regulator that adjusts the combustion amount of the burner, and a temperature deviation between the outlet temperature and the set temperature of the outlet temperature detector that detects the outlet temperature of the heat exchanger. feedback control means for controlling a combustion regulator according to the amount of water supplied; a water flow rate sensor that detects the amount of water supplied in the water supply channel of the heat exchanger; a water supply temperature sensor that detects the temperature of the water supply; and a water flow control valve that controls the amount of water supplied. and water supply amount setting means for calculating the capacity water supply amount by dividing the maximum capacity heat amount by the difference between the set temperature and the water supply temperature, that is, the heating temperature, and controlling the water supply amount to the capacity water amount value of the water supply amount setting means with a water flow control valve. and a water amount correction means for correcting an error in the capacity water supply amount value using a temperature deviation amount of the feedback control means, a subtraction value of the heating temperature, and a multiplication value of the water supply amount when the burner is at maximum combustion. Water temperature control device for water heaters.