JPS5846A - Water heater controlling device - Google Patents

Abstract

PURPOSE:To restrain water from being supplied beyond the maximum quantity of combustion and to obtain the temperature of tapped water alway equal to the set water temperature by controlling the amount of water supplied to a water heater on the basis of the difference of each signal from a temperature controller and a tap water temperature detector. CONSTITUTION:The output of a temperature controller 3 controls the quantity of combustion of a gas burner through a supply heat quantity controller 6 and adjust heating of water by a heat exchanger 2. A tap water temperature detector 4 is provided on the outlet of the heat exchanger. This detected signal and a signal from a temperature setter 5 are taken out as a differential signal in a water quantity controller 7. When the above-mentioned differential signal takes a fixed value or more by a timer signal from a timer section 8 equipped in the water quantity controller 7 even after a designated time passed, this control signal is transmitted to a supply water quantity controlling device 9, the supplied water quantity to the heat exchanger 2 is adjusted and the temperature of the tapped water is kept at the set temperature.

Description

[Detailed Description of the Invention] The present invention relates to hot water outlet temperature control for water heaters using gas, oil, electricity, etc. as heat sources, and eliminates the drawback of conventional devices that the set hot water temperature cannot be obtained when overloaded, thereby achieving the desired hot water temperature control. The purpose is to provide a new control device that can control the temperature of hot water.

glance The explanation will be given below using a gas water heater as an example.

FIG. 1 is a block diagram of a conventional gas water heater, in which combustion heat in a tank 1 and water are exchanged in a heat exchanger 2 to provide hot water.

A signal TWO from the hot water temperature detector 4 is sent to the temperature controller 3.
, the signal TWR from the temperature setting device 6 is input, and the TW
A predetermined combustion amount is determined from the difference between O and TWR, and a control signal is output to the supply heat amount controller 6 to control the hot water temperature. Here, as the outlet hot water temperature detector 4, for example, a thermistor is often used, and as the temperature controller 3, a PiD controller or the like is often used.

FIG. 2 is a diagram showing the relationship between the hot water output amount W of the gas water heater and the temperature rise. The solid line represents the characteristics at the maximum combustion amount. In other words, the maximum combustion amount Qqmax and the temperature rise Δ
T and the flow rate W are as follows, where η is the combustion efficiency, η-Q = W・ΔT (1)
It is max. Therefore, there is no temperature rise ΔT greater than that indicated by the solid line. For example, if the maximum combustion amount Q is max and the hot water output amount is Wl, the temperature rise ΔT becomes ΔT1 as shown in the figure. The temperature controller 3 described above operates effectively when the temperature rise is ΔT=ΔT1 and the hot water output amount W is less than W1. If W>Wl, control becomes impossible and the hot water outlet temperature TWO cannot reach the set temperature TWR.

Thus, the maximum combustion amount Ogmax l. Therefore, the amount W of hot water that can be controlled by the hot water temperature is limited.

This phenomenon is not limited to gas water heaters, but also applies to water heaters using other fuels.

The present invention provides a hot water temperature control device that eliminates the drawbacks seen in the hot water temperature control of the conventional water heater described above, and is capable of always obtaining a hot water outlet temperature TWO that is equal to the set temperature TWR.

FIG. 3 is a block diagram of the gas water heater of the present invention.

The water flow controller 7 receives a signal TWO from the hot water temperature detector 4.
, the signal TWR from the temperature setting device 5 and the temperature controller 3
It also has an internal timer part 8 for generating a predetermined time. Then, the aforementioned signals TWO and TW
By the difference TER of R and the signal from the timer part 8,
Supply water amount control device 9f: Outputs a control signal.

Items with the same numbers as in other W1 diagrams are devices having the same functions.

When starting to use a gas water heater, the maximum flow rate Wm&! The supplied water amount control device 9 is initialized so that the amount of heat supplied to the water heater is the maximum and the set temperature TWR is reached after a predetermined period of time has elapsed by the timer part 8 which starts counting at the same time as the start of use. Difference from exit hot water temperature [TWO TER = TWR - TWO
When is equal to or greater than a predetermined value, the supplied water amount control device 9 is operated to reduce the supplied water amount according to the TER, and the water amount is controlled so that the TER approaches zero. In addition, the timer part 8
starts counting when the temperature TWO changes when the set temperature changes or when the load fluctuates, that is, when TER exceeds a predetermined value, and calculates the water heater supply after a predetermined period of time as described above. The supply water amount control device 9 is operated according to the state of the heat amount and temperature deviation TER to obtain the set hot water temperature.

At this time, the predetermined time refers to the control performance of the temperature controller (for example, in the case of PiD control, it depends on the adjusted values of each parameter) and the delay time of the process, from an excessive state to a steady state (including insufficient capacity). This corresponds to the time it takes to settle down. In addition, if the amount of heat supplied to the water heater is not the maximum after a predetermined period of time has elapsed, the supply water amount control device 9 increases the amount of water supplied.
is operated so that the set hot water temperature can be obtained at the maximum flow rate by operating the hot water supply point.

FIG. 4 shows the hot water temperature characteristics (a) and hot water output control characteristics (b) and f of the gas water heater of the present invention. The horizontal axes each indicate the elapsed time t, which is the case when use is started with 1=0. After the start of use, at 1=11, when a predetermined period of time has elapsed, the amount of water supplied is reduced from Wmax to Wl based on the amount of heat supplied to the water heater and the deviation TER, and the TER is controlled to approach zero. t-t2
At the time when a predetermined period of time has elapsed after changing the flow rate, the water flow rate control operation determination is performed in the same manner as described above.

As described above, according to the present invention, the amount W of hot water dispensed is always limited to a range in which the temperature of hot water dispensed can be controlled, so hot water of a desired temperature can be obtained. In addition, it has a timer element that takes into account delay in response of the system to setting changes and load fluctuations, so there is no unnecessary water supply amount control operation in terms of hot water temperature control, and hot water temperature characteristics can be improved. .

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional gas water heater, and FIG. 2 is a characteristic diagram showing the relationship between hot water output amount and temperature rise of the gas water heater in FIG. 1.
FIG. 3 is a configuration diagram of a gas water heater showing an embodiment of the present invention;
FIGS. 4(a) and Φ) are response characteristic diagrams of the hot water temperature and the hot water amount, respectively, by the control device of the present invention. 3... Temperature controller, 4... Hot water temperature detector, 5... Temperature setting device, 6... Water heater supply heat amount controller, 7. ...Water flow controller, 8...
...Timer part, 9...Water supply amount control device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] The hot water temperature detector of the water heater, the temperature setting device, and the difference between the signal of the temperature setting device and the signal of the hot water temperature detector (TER)
a temperature controller that outputs a signal for controlling the amount of heat supplied to the water heater depending on the output of the water heater; a controller that controls the amount of heat supplied to the water heater in response to the output of the temperature controller; a water flow controller that outputs a signal to control the amount of water supplied depending on the signal of the timer portion and the TER; A water heater control device comprising: a water supply amount control device that controls the amount of water supplied.