JPH0346742B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an electric water heater that uses late-night electricity.

[Conventional technology]

A conventional electric water heater of this type had a configuration as shown in FIG. In the figure, 1 is a hot water storage tank, and a heating element 2 is attached to the lower part of the tank.
3 is a thermostat for controlling the boiling temperature, and is attached to the lower outer wall surface of the hot water storage tank 1.

Reference numeral 4 denotes a faucet for taking out hot water that has boiled up in the hot water storage tank 1. When the faucet 4 is opened, hot water in the hot water storage tank 1 is supplied under pressure from a water source connected to a water supply pipe 5.

Figure 5 shows the electrical circuit diagram of the conventional example.
7 is a power supply, and 7 is a time switch for setting the midnight power supply time.

Next, the operation of the above configuration will be explained. The capacity of the heating element 2 is set so that water at about 8°C is heated to a target temperature of 85°C within 8 hours during the late night power supply period. The thermostat 3, which has a normally closed contact, is configured to open the contact and stop supplying electricity to the heating element 2 when the water in the hot water storage tank 1 reaches 85°C. It is filled with 85℃ hot water.

[Problem that the invention seeks to solve]

However, the amount of hot water used is not always the same.
It changes greatly from day to day, depending on the season, and also due to changes in family structure. The above-mentioned conventional electric water heaters, which always boil water at a constant temperature such as 85 degrees Celsius, require setting the boiling temperature every day to keep up with these changes in the amount of heat required, which is cumbersome to operate. It is becoming more and more common for people not to operate the device after doing so. Therefore, it has become common to use the remaining hot water, and the hot water that has been boiled is left unused for a long time, resulting in a large loss of natural heat radiation from the hot water storage tank. It had the problem of becoming.

This invention attempts to solve these conventional problems.It boils only the appropriate amount of hot water according to the past boiling performance, the water supply temperature, the remaining hot water, etc., and also turns on the electricity to the heating element at the appropriate time. The object of the present invention is to obtain a control device for an electric water heater that reduces natural heat radiation loss.

[Means for solving problems]

The water heater control device according to the present invention includes a storage means for storing the past amount of remaining hot water, the boiling water temperature, and the net energization time to the heating element, and a temperature for detecting the water supply temperature to the hot water storage tank and the boiling water temperature. a sensor, a remaining hot water amount sensor that detects the amount of remaining hot water and the temperature of the remaining hot water, a remaining hot water amount determining means that determines the amount of remaining hot water from the detected value of the remaining hot water amount sensor, and an amount of remaining hot water determined by the remaining hot water amount determining means being externally transmitted. a means for displaying the amount of remaining hot water;
Maximum capacity setting means for switching the boiling capacity to the maximum, and when there is an input signal from this maximum capacity means, the maximum boiling target temperature is set, and when there is no input signal, the information stored in the storage means is set. a boiling target setting means for setting a boiling target applied electric power amount and a boiling target temperature based on the above-mentioned values, and detection values of the water supply water temperature and remaining hot water temperature by each of the sensors, an output signal of the remaining hot water amount determining means, and setting by the setting means. A calculation that calculates the net energization time to the heating element based on the boiling target applied power amount, and calculates the energization start time from the net energization time so that the boiling ends in the latter half of the late-night power supply period. and a control means for controlling the heating element to start energizing the heating element at the energization start time calculated by the calculation means and to stop energizing the heating element when the water temperature reaches the temperature set by the boiling target setting means. The remaining hot water amount determined by the residual temperature amount determination means, the net energization time to the heating element and the boiling water temperature controlled by the control means are newly input into the storage means. be.

[Effect]

In this invention, control is performed to boil only the appropriate amount of hot water based on the amount of hot water expected to be used the next day based on past results of hot water usage, the temperature of the supplied water, and the amount of hot water remaining in the hot water storage tank. The net energization time is calculated and the energization is controlled to start at a predetermined time.

〔Example〕

FIG. 1 is an overall configuration diagram of an embodiment of a control device for an electric water heater according to the present invention. As is clear from FIG. 1, in this embodiment, a temperature sensor 8 for detecting the supply water temperature and boiling temperature is installed at the lower part of the hot water storage tank 1, and a plurality of sensors 9a for detecting the amount of remaining hot water and the temperature of the remaining hot water are installed at the upper part. 9b and 9c are provided respectively, and the remaining hot water amount is determined by the remaining hot water amount determining means 10 based on the detection signals of the remaining hot water amount sensors 9a, 9b, and 9c, and the remaining hot water amount is determined by the remaining hot water amount displaying means 13 based on the output signal. indicate.

On the other hand, according to the input signal from the maximum capacity setting means 12, the boiling target setting means 11 sets the maximum boiling target temperature (for example, 85° C.) or the state of the past water usage amount read out from the storage means 16, which will be described later. Based on the results of the remaining hot water amount, boiling temperature, and net energization time, the amount of electricity and boiling temperature that are expected to be required the next day are set, and this result, the detection signal of the water supply water temperature by the temperature sensor 8, and the remaining hot water amount determination means 10 Based on the result, the calculation means 14 calculates the net energization time required to boil the appropriate amount of water and the energization start time from when the time switch 7 is turned on until the energization is applied to the heating element 2, and based on the results. Based on this, the heating element 2 is controlled by the control means 15, and after the completion of boiling, the water temperature detected by the temperature sensor 8, the net energization time to the heating element 2, and the remaining water amount sensors 9a, 9b, The amount of remaining hot water detected by 9c is stored in the storage means 16. FIG. 2 is a circuit diagram showing the electrical connections of the embodiment of FIG. 1. In the figure, 17 is a microcomputer in the control circuit, including a CPU 18, memory 19,
It has an input circuit 20 and an output circuit 21. The heating element control circuit 22 includes a resistor 23 and a transistor 2.
4. It is composed of relays 25 and 26.

The energizing coil 25a of the relay 25 is connected between the positive terminal +V and the GND terminal via the emitter and collector terminals of the transistor 24, and the base terminal of the transistor 24 is connected to the output circuit 21 via the resistor 23. ing.

The contact 25b of the relay 25 is connected to the relay 26.
The energizing coil 26a and the power source 6 are connected in series. A contact 26b of the relay 26 is connected in series to the heating element 2 and the power source 6.

27, 28, 29, and 30 are resistors connected in series with the temperature sensor 8 and remaining hot water amount sensors 9a, 9b, and 9c, and 31 is also input with the detection outputs of the temperature sensor 8 and remaining hot water amount sensors 9a, 9b, and 9c. An analog multiplexer 32 is an A/D converter that converts its output into a digital value, 33 is a boiling capacity changeover switch connected in series with a resistor 34, and these detection signals are given to the input circuit 20.

The light emitting diodes 38, 39, 40 connected in series with the resistors 35, 36, 37 are connected to the remaining hot water amount sensor 9.
The output circuit 21 controls the lights to be turned on based on the detection signals of a, 9b, and 9c.

Next, the operation of the above embodiment will be explained with reference to FIG.

Figure 3 shows memory 1 of microcomputer 17.
9 is a flowchart showing the heating element control stored in FIG. First, when the power is turned on, initial setting of the target applied power amount P and target temperature T for boiling, shown in step 41 in FIG. 3, starts. Next, the process proceeds to step 42, where the applied power amount correction coefficient α is set.
The initial values are P=4.4×8Kw, T=85℃,
Give α=1.0.

At step 43, the water temperature Tw is read, at step 44 the remaining hot water temperatures Tz ₁ , Tz ₂ and Tz ₃ are read, and based on the results, the amount of remaining hot water is displayed at step 45.

Next, in step 46, the switch is read to determine whether the boiling capacity is at its maximum (for example, 85°C boiling) or predicted boiling based on past water usage results.

This control device is capable of boiling water at its maximum capacity (e.g., 85℃) in order to follow specific changes in the amount of hot water used by the user. In addition, when the amount of hot water used does not fluctuate much, there is a boiling mode that predicts the amount of hot water used the next day based on the past results of hot water usage, so in unusual cases that do not suit a certain daily rhythm, for example, when switching to the maximum capacity, this mode can be used. It is not appropriate to use this as a criterion for predicting boiling.

Therefore, in step 47, it is determined whether the previous day's boiling capacity was at its maximum capacity, and if not, the remaining amount of hot water is stored in step 48.

Next, check whether the boiling temperature is at its maximum on the day Step 4
9, and if it is the maximum, step 50 determines the target applied electric power for boiling as P=V×(85−Tw)/860×η. Here, η represents heating efficiency, and V represents hot water storage tank capacity. The target boiling temperature at this time is T
=85℃.

Next, in step 51, the target applied power amount P for boiling
and the net energization time to energize heating element 2 based on the amount of remaining hot water.
Find Ha.

Ha=(P-Vz×(Tz-Tw)/860×η)/W Here, Vz is the remaining hot water amount sensor 9a, 9b,
This is the amount of remaining hot water based on the detection signal of 9c, and is determined by the mounting position of the sensor.

Tz is the temperature at the sensor mounting position, and W is the power consumption of the heating element 2.

In step 52, the net energization time Ha required for boiling determined in step 51 is calculated in the latter half of the midnight power supply period, that is, when the time switch 7
This is the part that determines how many hours after turning on the power should start.

H=8-Ha Step 53 is to check whether the time switch 7 has been turned on, and at the same time as it is turned on, step 54 is to check the elapsed time of the energization start time H.

After H time has elapsed, the process proceeds to step 55 to start energizing the heating element 2, and it is determined in step 56 whether or not the water temperature has risen to the target temperature T. If the determined results are equal, step 57
In step 57, the heating element 2 is turned off, and if the target temperature has not yet been reached, it is checked in step 57 whether the time switch has been turned off.

As a result, if the state is ON, the process returns to step 56, and if it is OFF, step 58 is executed.

In step 59, it is determined whether or not the boiling capacity on that day was at its maximum capacity. If not, in step 60, the net energization time up to the point of completion of boiling and the boiling water temperature are measured by the temperature sensor 8, and the temperature is stored in the memory 19. to be memorized.

Next, in step 61, the net energization times Ha ₁ , Ha ₂ , . . . for the past n days, which have already been stored in the memory 19, are calculated.
…Han, boiling temperature T ₁ , T ₂ …Tn, amount of remaining hot water
Vz ₁ , Vz ₂ . . . Vzn are read out, and the average power consumption Pav is determined from the net energization times Ha ₁ , Ha ₂ .

The remaining hot water amounts Vz ₁ , Vz _{2 .} . . Vzn are compared with the previously determined standard remaining hot water amount V _B in step 63,
As a result, if the amount of remaining hot water is greater than the standard amount of remaining hot water V _B , it is determined in step 64 whether the current day is more than m consecutive days (for example, m = 3 days), and if it is more than m days, the amount of applied electric power is corrected in step 65. Modify the coefficient α (eg α=α−0.1).

Further, if the determination result in step 63 is that the amount of remaining hot water is less than the standard amount of remaining hot water _VB , it is determined in step 66 whether or not the day is consecutive m days or more,
If it is more than m days, step 67 is executed to correct the applied power amount correction coefficient α (for example, α=α+0.1).

In cases other than the above, the process proceeds to step 68, and the correction coefficient α obtained here is used in step 68 to determine the target applied power amount P for boiling. That is, P=Pav×α Next, the hot water temperature T ₁ read in step 61,
T _{2 .} . . The maximum value of Tn is determined as the target boiling temperature T for the next day in step 69.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to predict the amount of boiling water for the next day based on the amount of hot water used in the past, and to switch the boiling capacity when using hot water that does not match the normal rhythm of life. The system is configured to boil only the appropriate amount of hot water based on the water supply temperature and the state of the remaining hot water in the hot water storage tank, so it is possible to automatically predict the required amount of hot water, and by displaying the remaining amount of hot water, The amount of hot water used can be adjusted, reducing the amount of remaining hot water and reducing maintenance costs.

Furthermore, since the energization time can be predicted, a peak shift effect can be expected.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram showing one embodiment of the control device for an electric water heater according to the present invention, Fig. 2 is a circuit diagram showing its electrical connections, Fig. 3 is a flowchart showing its operation, and Fig. 4 is FIG. 5 is a schematic configuration diagram showing a conventional hot water storage type electric water heater, and FIG. 5 is its main electric circuit diagram. In the figure, 8 is a temperature sensor, 9a, 9b, 9c
10a is a remaining hot water amount sensor, 10a is a remaining hot water amount determining means, 11
1 is a boiling target setting means, 12 is a maximum capacity setting means, 13 is a remaining hot water amount display means, 14 is a calculation means, 1
5 is a control means, 16 is a storage means, 17 is a microcomputer, and 22 is a heating element control circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a water heater that uses late-night electricity, a storage means that stores the past amount of remaining hot water, boiling water temperature, and net energization time to the heating element, and a temperature sensor that detects the temperature of water supplied to the hot water storage tank and the temperature of boiling water. , a remaining hot water amount sensor that detects the amount of remaining hot water and the temperature of the remaining hot water, a remaining hot water amount determining means that determines the amount of remaining hot water from the detected value of the remaining hot water amount sensor, and an external display of the amount of remaining hot water determined by the remaining hot water amount determining means. When there is an input signal from the remaining hot water amount display means, the maximum capacity setting means for switching the boiling capacity to the maximum, and the input signal from this maximum capacity setting means, the maximum boiling target temperature is set, and when there is no input signal, the A boiling target setting means for setting a boiling target applied power amount and a boiling target temperature based on information stored in the storage means, and outputs of detected values of the supply water temperature and remaining hot water temperature by each of the sensors and the remaining hot water amount determining means. The net energization time to the heating element is calculated based on the signal and the boiling target applied power amount set by the setting means, and the boiling is completed in the latter half of the late night power supply period from the net energization time. a calculation means for calculating an energization start time; and when the energization start time calculated by the calculation means is reached, energization to the heating element is started, and when the water temperature reaches the water temperature set by the boiling target setting means, energization to the heating element is stopped. a control means for controlling the stoppage, and a new amount of remaining hot water determined by the residual temperature determination means, a net energization time to the heating element and a boiling water temperature controlled by the control means are stored in the storage means. Input water heater control device.