JPS58205041A - Control of hot-water supplying machine - Google Patents

Abstract

PURPOSE:To obtain hot-water of a desired temperature at all times by a method wherein a load fluctuation, due to the change of the inlet pressure of water, and the variation of the capacity of a water supplying amount control device are absorbed. CONSTITUTION:An outlet hot-water temperature detector 4 and an inlet water temperature detector 8 are provided at the outlet side and the inlet side of a heat exchanger 2, and a set temperature signal (TWR) from a temperature setting unit 5, an outlet hot-water temperature signal (TWO) and an inlet water temperature signal (TWi) are inputted into a temperature control unit 7 while a control unit 6 of a heat amount supplied to a burner 1 is controlled based on a difference (TER) between the outlet hot-water temperature signal (TWO) and the set signal (TWR). When the set signal (TWR) is changed by more than a predetermined value (TWRC), the water supplying amount control unit 9 is set based on the difference (TUP) between the inlet water temperature signal (TWi) and the set signal (TWR), thereafter, the water supplying amount control unit 9 is controlled when a condition, in which the difference (TER) is lower than a permissible predetermined value (TER1), is continued for a predetermined period of time t0.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot water temperature control method in which hot water at a set temperature can be obtained at any time by automatically adjusting the amount of hot water supplied in a water heater using gas, oil, electricity, etc. as a heat source.

2.7' Here, the explanation will be given using an example of water temperature control in a water heater that uses gas as fuel.

Fig. 4 is a block diagram of a conventional gas water heater, in which combustion heat in a gas burner 1 serving as a heat source is exchanged with water in a heat exchanger 2 to supply hot water. The temperature controller 3 inputs the signal TWO from the hot water temperature detector 4 and the signal TWR from the temperature setting device 6, determines a predetermined combustion amount from the deviation of the signals (TER2TWR-TWO), and controls the amount of heat supplied. The hot water outlet temperature TWO is controlled by controlling the container 6. Typically,
A thermistor or a thermocouple is often used as the hot water temperature detector 4, and a proportional-integral-differential method (PiD method) or a control law based on a combination thereof is often used as an algorithm for controlling the hot water temperature.

FIG. 3 is a performance characteristic diagram of the gas water heater, showing the relationship between the hot water supply amount Fw and the temperature rise value ΔT at the maximum combustion amount Qgmax of the device. Said Qgmax, Fw.

ΔT is 77-Qgmax-ΔT-FW (1
), and furthermore, ΔT −:η ・QgmaX/FW
It is expressed as (2). That is, at each hot water supply level, there is no temperature rise exceeding the capacity characteristic shown in the figure. For example, the amount of hot water supplied at maximum combustion is FWI
At this time, the temperature increase value becomes ΔT1 as shown in the figure. The temperature controller 3 mentioned above calculates the difference between the signal of the temperature setting device 5 and the inlet water temperature TWi, that is, the value TU to be increased in temperature.
When P is ΔTl, it acts effectively in the region of the hot water supply amount FwlFwl. However, in the hot water supply amount range of Fw′)Fw+, that is, in the overload region, the hot water temperature cannot be controlled, and the hot water temperature will never reach the set temperature no matter how long it takes.

In this way, the maximum combustion amount qgmaxi limits the amount of hot water supply that can control the hot water temperature.

The present invention eliminates the drawbacks of 1ffi as described above, and eliminates the fluctuations due to changes in the inlet pressure of the water that is the load and the equipment 111.
11111 It is an object of the present invention to provide a hot water temperature control method that absorbs variations in a water supply amount controller that is a constituent element and can always provide hot water at a desired temperature.

In order to achieve the above object, in the present invention, based on the hot water supply function characteristics shown in Fig. 3, the inlet water temperature TWi and the set temperature TWR are
The supply water amount Fw is set to a predetermined value from the signal difference TUP,
Hot water temperature control is started. However, due to fluctuations in the supply water pressure of the water heater or variations in the supply water flow rate controller or incoming water temperature detector, which are component parts of the device, the predetermined set water volume may not be achieved as described above. In order to correct this deviation from the predetermined set water amount value, a predetermined time t is set after the start of hot water temperature control, taking into account the delay of the heat exchanger, which is the controlled process.
If the hot water temperature deviation TER is larger than the allowable predetermined value TERI in the steady state of 0, the operation of reducing the supply water amount by a predetermined amount is repeated, and as a result, the gain of the process increases and the hot water temperature approaches the set value.

Furthermore, in the present invention, during the hot water temperature control, the set temperature TW
When R is changed to a predetermined value TWRC, the amount of water supplied is controlled to a predetermined value based on the signal difference between the changed set temperature edge and the inlet water temperature. Thereafter, water flow control is performed based on the hot water temperature deviation in the steady state after the elapse of the above-mentioned predetermined time period.

By the way, when starting to use the water heater, the temperature setting device signal TW
It is assumed that R has become two liquids with a predetermined value TWRC, and the Off
The amount of water supplied is controlled as described above.

Further, during the hot water temperature control, the incoming water temperature is constantly monitored, and when controlling the amount of supplied water based on a change in the set temperature, the incoming water temperature transformation '1jTWi at that time is applied. However, fluctuations in the incoming water temperature are so small that outside the temperature gradient of the water that has accumulated in the part of the water supply pipe that comes out to the ground appears when the water heater starts to be used, so the set temperature is determined only by fluctuations in this signal TWi. Even if the difference TUP from TWR changes, water flow control is not performed.

FIG. 1 is a configuration diagram of a gas water heater of the present invention.

The same numbers as in FIG. 4 indicate components having similar functions. The temperature controller 7 inputs the output water temperature sensor 4 signal ';jTWO, the temperature setting device 5 signal TWR, and the input water temperature sensor 8 signal '13TWi,
A predetermined combustion amount is determined from the deviation of δ to control the supply heat amount controller 6, and a third combustion amount is determined based on the difference TUP between TWR and TWi.
Based on the characteristics shown in the figure, the water temperature is 6 1. ``Control the supply water amount controller 9 to a controllable hot water supply amount Fw. According to this method, hot water at the set temperature is always obtained.

one! In addition, as described in 1171, in order to absorb fluctuations in the amount of hot water supplied due to fluctuations in water pressure, etc., or variations in the characteristics of the water supply amount controller 9 of the equipment components, the temperature deviation TF,
The supply water amount controller 9 is controlled according to H. In other words, after the aforementioned water flow control according to TUPK, in a steady state after a predetermined period of time has elapsed, taking into account the response delay of the heat exchanger, etc., the deviation TER
is greater than the predetermined value TERI, the amount of water is further reduced.

Since the temperature controller 7 in this figure receives the signal TWR from the temperature setting device 5, it detects changes in the signal TWH, and when the change exceeds a predetermined value TWRC, the inlet water temperature TWi
The supply water amount controller 9 is driven according to the difference TUPK.

Next, in Figure 2, (a) set temperature TWR and water inlet temperature TWi
, (b) change in outlet temperature TWO, and (C) change in supplied water amount FW. The horizontal axis represents the elapsed time,
Hot water supply has started at 1-0.

7. At the start of hot water supply at t=○, the amount of hot water supplied is FWI according to the difference TUPI between the set temperature TWRI and the inlet water temperature TWi+.
is set to . t = ts2 is when the predetermined time to has elapsed for the heat exchange system to reach a steady state, and during this t2 period, due to the lack of capacity as a water heater, the supply heat capacity is increased by i and almost reaches the maximum. Burning continues. Since the hot water temperature deviation during the above-mentioned to period is larger than the predetermined value TERIJ, the supplied water amount is reduced by a predetermined amount at t-t2 to become FWII.

This operation increases the gain of the heat exchange system, and as shown in Figure b, the outlet temperature TWO becomes equal to the set temperature TWRI. Next, the set temperature is changed in the period from 1=1s3 to 1=184, and becomes TER2.

Since the amount of change at this time is larger than the predetermined value TWRCi, the predetermined value F is determined by the signal difference TUP2 with the inlet water temperature TWi.
The amount of water supplied is limited until w2.

After that, the hot water temperature is controlled and approaches the fixed value. As described above, the area around 2 tsI indicates the occurrence of a change in the inlet water temperature at the time of starting use of the water heater, but the amount of water supplied is not controlled only by the signal change from the set temperature due to this change.

By the way, the reason why the predetermined value TWRC is set for the signal change of the set temperature is that when the set temperature signal is composed of +m normal electronic circuits, noise is often superimposed on the set temperature signal, This is to prevent this, since changing the water temperature leads to instability in hot water temperature control.

To realize such a control method, methods such as management and execution of a programmable control law using a microcomputer, which has been widely used in recent years, and combination with each element drive unit may also be considered.

As explained above, according to the water heater control method of the present invention, the amount of water supplied is always regulated within a range where the temperature can be controlled, so hot water of the desired temperature is always obtained, and the amount of water supplied is It is possible to operate to obtain the set temperature even when there are fluctuations in temperature. In addition, when the set temperature is changed by the user, the amount of water supplied is controlled according to the value that the temperature should rise at that time, so controlling the amount of water is effective against slight fluctuations in the incoming water temperature, and the temperature of the outgoing water is 90%.・
- ゛It has the effect of improving stability.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the gas water heater of the present invention, and Figure 2 is (8L
) Setting temperature and water inlet temperature, (b) Output temperature, (C) Time characteristic diagram of hot water supply amount, Figure 3 is a capacity characteristic diagram of a gas water heater, Figure 4
The figure is a configuration diagram of a conventional gas water heater. 4... Output water temperature detector, 5... Temperature setting device, 6... Supply heat amount controller, 8... Incoming water temperature detector, 9...・・Supply water amount controller, TER・
...Water temperature deviation. Name of agent: Patent attorney Masao Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] Inlet water temperature detector, outlet water temperature detector, temperature setting device,
A supply heat amount controller and a supply water amount controller are provided, and the temperature is controlled depending on the deviation (T K R) between the signal (T W R) of the temperature setting device and the signal (T W O) of the hot water temperature detector. The supply heat amount controller is controlled and the temperature setting device signal (T
When the signal (T W R) changes by more than a predetermined value (T W Rc), the signal (T W R) and the signal (T W Rc) of the water temperature sensor
After setting the supply water flow rate controller depending on the difference ('T U P) between the deviation (T W A method for controlling a water heater, which controls the water supply amount controller when