JPS586855B2 - electric water heater device - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in electric water heaters.

Recently, electric water heaters that use late-night electricity have been used, and these types of electric water heaters are used for purposes such as washing dishes or supplying hot water to bathtubs, where the water temperature is lower than the water temperature in the hot water tank. For electric water heaters used to heat hot water,
When used, water is mixed with the hot water supplied from the hot water tank,
The capacity of the hot water tank and the hot water storage temperature are set so that a predetermined amount of hot water having a substantially constant temperature lower than the hot water temperature in the hot water tank can be obtained.

However, in conventional water heaters of this type, the hot water storage temperature is 80°C to meet the maximum amount of heat required in winter when the water temperature is low.
Since the water temperature was set between 90°C and 90°C, the entire amount of hot water in the tank is not used up during the summer when the water temperature is high.

Therefore, if the hot water storage temperature is set high, the difference between the hot water storage temperature and the outside temperature becomes large, so that a large amount of heat is dissipated to the outside through the tank, resulting in wasted energy consumption.

SUMMARY OF THE INVENTION An object of the present invention is to propose an electric water heater device that eliminates the above-mentioned drawbacks by controlling the temperature of stored hot water in relation to the temperature of water mixed with hot water supplied from a hot water tank.

The present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of the power-saving electric water heater device according to the present invention, in which 1 is a hot water tank, 2 is a heat insulating material that covers the outer surface of the tank to keep the hot water tank 1 warm; 3 is a heater attached to the side wall of the hot water tank so as to be located near the bottom of the tank.

Reference numeral 4 denotes a hot water temperature detection element for detecting the temperature of hot water in the hot water tank 1, which is disposed above the heater 3 and close to the heater.

5 is a water supply pipe that supplies water from the bottom of the hot water tank 1 into the tank and also supplies water to be mixed with the hot water supplied from the hot water tank 1; 6 is a hot water pipe installed at the top of the hot water tank 1; A water faucet 7a and a hot water faucet 7b are attached to the water supply pipe 5 and the hot water supply pipe 6, respectively.

8 controls the water temperature according to the temperature of the water supplied to the hot water tank 1 and the water faucet 7a. With the water temperature controller,
Energization of the heater 3 is controlled by obtaining input signals from the hot water temperature detecting element 4 and a water temperature detecting element 9 installed in the water supply pipe 5 to detect the temperature of water.

Note that 10 is a time switch that limits the power supply time of late-night power.

In such a configuration, as shown in FIG. 2, the amount of hot water stored in the hot water tank 1 is expressed by the temperature of the hot water storage et Q, the water supply temperature (temperature of water in the water supply pipe) is θs (°C), and the amount of hot water stored is V.
Assuming that the amount of hot water obtained by mixing appropriate amounts of hot water at temperature t (l) and water at temperature θsCQ is Vo(l), and the temperature of this hot water supply is θo(Q), the following equation holds true.

Vt・θt(Vo-Vt)・θs=Vo・θ0 ・・
...(1) Vo Vo -V t From equation (1), θt -θ0-θS ...
(2) vt vt Vo−Vt in the above formula corresponds to the amount of mixed water.

Here, Vt is a constant, and although Vo and θ0 vary slightly depending on the season and situation, macroscopically they are approximately constant and can be considered constants, so θS and θt are calculated (2
) If the water temperature controller 8 is configured to stop energizing the heater 3 when the equation is satisfied, the water temperature θS
It is possible to obtain the minimum necessary hot water storage temperature according to the required temperature, and it is possible to prevent the waste of storing hot water at an unnecessarily high temperature.

As an example, V o = 400A! , θo-45℃,
When Vt=200#, from equation (2), θt-90-
θS...(3).

The relationship between the water temperature θS and the hot water storage temperature θt in this case is illustrated in FIG. 3, and it can be seen that the higher the water temperature θS, the lower the hot water storage temperature can be.

Water temperature θS is generally in the range of 5°C to 30°C throughout the four seasons, but if the water temperature is 25°C in the summer, it will be θt-65°C, which means that the conventional hot water storage temperature was set at 80°C to 90°C. The difference between the hot water storage temperature and the outside temperature is much smaller than in the case of

Therefore, the amount of heat radiated during hot water storage can be reduced compared to the conventional method, and together with not consuming unnecessary electrical energy, it is possible to save energy to a large extent.

In the above explanation, the required amount of hot water Vo is constant, but even if the required amount of hot water changes depending on the season, equation (2) can be used in the same way.

For example, if Vo=300l instead of Vo=400l, equation (3) becomes θt=6 7.5-0.5θS
(3γ), and by providing the hot water temperature controller 8 with a switch for changing the required amount of hot water, it is possible to control the hot water temperature in accordance with the required amount of hot water.

Similarly, it is also possible to configure the hot water supply temperature θ0 to be changeable.

Note that when the required hot water supply amount Vo is smaller than the hot water storage amount (Vt) in the hot water tank, the following equation is applied in place of the above-mentioned equation (2).

θtVOθoVo-K. −Vtθs −・・−(
21K-Vt K-Vt Here, K is a constant determined approximately based on the ratio of Vo/Vt, and has a value of 1>K>0.

As an example, ■o-100l, θO-45°C, Vt=
200l, K=0.25, from equation (2), θt=
90-θS, which is the same as equation (3).

In this case, 50 liters of hot water is supplied from the tank (1) and mixed with water to provide 100 liters of hot water.

Note that the required amount of hot water Vo for one time is the amount of hot water stored in the tank (1) v
If t is significantly exceeded, the hot water stored in the tank (1) will be used up, and hot water supply exceeding the supply capacity will become impossible.

Therefore, the capacity of the tank (1) may be determined based on the maximum amount of hot water required at one time.

Referring to FIG. 4, a configuration example of a hot water temperature controller that controls the hot water temperature according to equation (3) is shown.

In the figure, e is an AC power source, and an electric heater 3 is connected to both ends of this power source via a constant contact CR1a of a switch SW and a relay.

A transformer T1 is also connected to the power supply e via a switch SW, and the output of the transformer T1 is connected to a rectifier D1 and a capacitor C1.
is applied to a constant voltage rectifier circuit consisting of a resistor R1 and a Zener diode ZD1.

The voltage across the Zener diode ZD1 is the normally open contact CR
1a is applied between the collector and emitter of the transistor TR through the relay coil CR1, and the anode is connected between the collector of the transistor TR1 and the connection point of the Zener diode ZD1 and the relay coil CR1.
A diode D2 is connected to the R1 side.

Further, the cathode and anode of the Zener diode ZD1 are connected to the transistor TR through resistors R2 and R3, respectively.
connected to the collector and emitter of transistor T
The emitter of R2 is connected to the base of the transistor TR through a series circuit of a Zener diode ZD2 and a resistor R4.

The collector and emitter of a transistor TR3 are connected to the collector and base of the transistor TR2, respectively, and the base of the transistor TR3 and the Zener diode Z are connected to each other.
A positive temperature characteristic resistor Pr1 as the hot water temperature sensing element 4 and a positive temperature characteristic resistor Pr2 as the water temperature sensing element 9 are connected in series between the cathode of D, and the positive temperature characteristic resistor is made of, for example, copper. Alternatively, use a wire-wound resistor made of platinum whose resistance changes linearly with temperature.

Also, the base of transistor TR3 and Zener diode Z
A variable resistor R is connected between the anode of D and the anode of R.

In the circuit shown in FIG. 4, the temperature positive characteristic resistor Pr and . Voltage e1 across the series circuit of P r2, variable resistor R
If the voltage across 5 is e2, then when e1<e2, the Zener diode ZD2 is conductive and the switching transistor TR is turned on, and when e1>e2, the Zener diode ZD2 is non-conductive and the switching transistor TR1 is turned off. Become.

When the switching transistor TR1 is turned on, current flows through the relay coil CR, closing the relay contact CR1a.

Therefore, the resistance value of each temperature positive characteristic low antibody and the resistance value of variable resistor R5 are set so that when the hot water storage temperature θt rises and the sum of θt and water temperature θS satisfies equation (3), 01>e2. By setting , the water temperature can be controlled according to equation (3).

FIG. 5 is a schematic configuration diagram showing another embodiment of the power-saving electric water heater device according to the present invention, and the difference from FIG. 1 is that a solar water heater is combined.

That is, in the figure, the heater 3 is placed at an appropriate position in the middle of the hot water tank 1, and accordingly, the hot water temperature sensing element 4 is placed close to the top of the heater 3.

In this case, the capacity of the tank is set so that the amount of heat above the heater 3 satisfies the daily consumption of hot water.

11 is a solar water heater, with upper and lower water pipes 1 2 . 1
The heater 3 is connected to the hot water tank 1 located below through 2'.

In addition, 13 is a pump 1 placed in the middle of the water pipe 1'2'.
This controller controls the operation of the solar water heater 4, and operates using the detection signal of the solar heat detection element 15 arranged in the solar water heater as an input signal.

In this way, the water above the heater 3 in the hot water tank 1 is boiled to a constant temperature by the hot water temperature controller 8 using late-night electricity.

Also, when the situation becomes such that solar heat can be used the next day, the solar heat detection element 15 detects this and the controller 13 controls the pump 1.
4 is operated, and the water below the heater 3 is circulated through the hot water tank 1 - water pipe 12 - solar water heater 11 - water pipe 12 - hot water tank 1 to warm the water below the heater 3.

When the hot water above the heater 3 is consumed during hot water consumption in the evening or at night, the hot water heated by the solar water heater is pushed up above the heater 3 by the water supply pressure. The temperature is further increased.

By further heating water heated by solar heat in this way using late-night electricity, power consumption can be significantly reduced.

The operation of the hot water temperature controller 8 in this embodiment is as follows.
This is the same as the case shown in the figure.

As described above, according to the present invention, the temperature of the supplied water,
Since the temperature of the hot water stored in the hot water tank and the temperature of the hot water stored in the hot water tank are detected, and the power supply to the heater is controlled in relation to both detected temperatures, the required amount of hot water at a predetermined temperature can be covered with the minimum amount of electrical energy required, which saves energy. This has the advantage of allowing significant savings to be made.

Particularly in the summer when the water supply temperature is high, the temperature of the hot water stored in the hot water tank can be lowered considerably compared to the conventional method, which reduces the difference between the outside air temperature and the stored hot water temperature, making it possible to suppress heat radiation during hot water storage.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining the operation of the water heater device of the present invention, and FIG. 3 is an example of the relationship between supply water temperature and hot water storage temperature. The diagrams shown in FIGS. 4 and 5 are schematic configuration diagrams showing other different embodiments of the present invention, respectively. 1...Hot water tank, 3...Heater, 4...
...Water temperature detection element, 5...Water supply pipe, 6.
...Hot water pipe, 8...Hot water temperature controller,
9...Water temperature detection element.

Claims (1)

[Claims] 1 Water supplied into a hot water tank is heated by an electric heater and stored, and when hot water is used, the hot water supplied from the tank is mixed with water to produce hot water at a substantially constant temperature lower than the temperature of the hot water in the tank. In the electric water heater device, the hot water temperature sensing element detects the temperature (θt) of hot water in the hot water tank, and the water temperature sensing element detects the temperature (θS) of water supplied to the hot water tank. and a hot water temperature controller that controls energization of the electric heater based on detection signals from both the hot water temperature sensing element and the water temperature sensing element, and the hot water temperature controller is configured to detect when the water temperature (θS) is at the bottom. In this case, the temperature (θt) of the hot water stored in the hot water tank is increased, and when the temperature (θS) of the water is high, the temperature (θt) of the hot water stored in the hot water tank is lowered. An electric water heater device characterized in that the electric water supply to the electric heater is controlled in relation to the temperature (θS) of the water.