JPH04257654A - Control device for electric water heater - Google Patents

Abstract

PURPOSE:To determine power failure reset for a midnight electricity time zone by a simple circuit, and cancel peak shift. CONSTITUTION:A non-boiling condition is stored in a memory means 6 as an initial condition, and when a boiling signal is output from a temperature control means 4, a boiling condition is stored in the memory means 6. At the time of the next power supply starting, a memory determination means 7 determines the condition of the memory means 6. If a boiling condition is stored, power supply starting for midnight electricity is performed by peak shift, and when a non-boiling condition is stored, it is determined to be reset from a power failure, and peak shift is canceled. Also, the memory means 6 is constituted by self-retaining type relays to provide a simple circuit.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater that uses late-night power to control the power supply of a control device using only late-night power and also performs peak shift control.

0002

[Prior Art] An electric water heater, which is generally called an energization control type electric water heater, uses a control device to calculate the necessary heater energization time based on data such as boiling temperature setting and water temperature, and calculates the required heater energization time approximately at the time when electricity is finished at midnight. The heater energization start time is delayed from the midnight power energization start time so that boiling is completed in time for the boiling (this delay time is called the peak shift time). The purpose of peak shifting is to eliminate the peak demand for electricity that conventionally occurs when late-night power starts, and also to reduce heat loss from electric water heaters by bringing the boiling time closer to the end of late-night power. It is in.

However, in order to perform a peak shift from the start of late-night power supply, it is necessary to distinguish between the start of late-night power supply and the recovery from a power outage that occurred during the late-night power supply period. This is because if a power outage occurs during a peak shift, the heater energization time will be shortened by the peak shift time before the power outage and the time of the power outage, and the boiling will not reach the set boiling temperature. Therefore, it is necessary to perform a peak shift when the late-night power supply starts, and to cancel the peak shift when recovering from a power outage that occurs during the late-night power supply time.

[0004] Conventionally, in order to determine the start of late-night power supply and recovery from a power outage that occurred during the late-night power supply period, a 100V power supply that is always energized was wired separately from the power supply wiring for late-night power, and the late-night power supply was If power supply was started at the same time as 100V power and 100V power supply, it was determined that the power had returned from a power outage, and if late-night power supply was started while 100V power supply was being supplied, it was determined that late-night power supply had started.

[0005] Also, it is called a 100V-less electric water heater.
Electric water heaters that omit the 00V power supply are being implemented,
These devices are backed up by storage batteries etc. during the daytime hours when late night power is not supplied, and any power supply outage that is less than the midnight power supply time (e.g. 8 hours) is recognized as a power outage time, and the charging/discharging circuit is The power outage detection means used determines the start of late-night power supply and the return of power outage (Japanese Unexamined Patent Publication No. 197757/1999).

[0006]

[Problem to be solved by the invention] However, the above 1
In a configuration using a 00V power source, wiring for a 100V power source is required, and there is a problem in that the cost of electrical work increases when installing an electric water heater. In addition, in the configuration of the above-mentioned 100V electric water heater, a control means that operates when power is not being supplied is provided to detect a power outage, so the backup storage battery is expensive and the charging/discharging circuit is Since this method uses the long-time discharge of a capacitor, it is necessary to use a capacitor with high capacity and high precision, resulting in an expensive problem. Further, in the charging/discharging circuit, temperature characteristics, aging, etc. greatly affect the discharge characteristics, and it has been difficult to reduce variations in discharge time.

[0007] The present invention solves the above problems.
The purpose of the system is to determine whether late-night power is turned on or when power is restored from a power outage, rather than using a control device that operates when power is not being supplied, such as when backing up a power source, but rather to use a control device that operates reliably when power is being supplied. The present invention provides a water heater control device.

A second object is to provide a control device for an electric water heater that achieves the first object with a simple circuit and at low cost.

[0009]

[Means for Solving the Problems] In order to achieve the above first object, the present invention provides a temperature detecting means for detecting the temperature in a hot water storage tank, a hot water temperature setting means for setting a boiling water temperature, and a hot water temperature setting means for setting the temperature of boiling water. peak shift calculation means for delaying the start of heater energization based on the temperature data obtained by the detection means and the hot water temperature setting means; and a storage means for storing the fact that the temperature control means has detected boiling, and when the boiling detection is not stored in the storage means when power supply is started. The apparatus further includes a memory determining means for canceling the peak shift time calculated by the peak shift calculating means.

[0010] In order to achieve the above second object, the present invention has the following features:
The storage means is constituted by a self-holding type relay in which one state of the open/closed state of the contact is set as boiling-up detection, and the other state is set as boiling-up not detected.

[0011]

[Function] A state of no boiling is stored in the storage means as an initial state, and when a boiling signal is output from the temperature control means, a state of boiling is stored in the storage means,
The storage determination means determines the state of the storage means at the next start of power supply, and if the boiling state is stored, this start of power supply is determined to be the start of late-night power supply, and the no-boiling state is stored. If so, it is determined that the system has returned from a power outage, and thereby determines whether late-night power supply has started or whether the system has returned from a power outage.

[0012] Furthermore, by configuring the memory means with a self-holding relay in which one state of the open/closed state of the contact is set as boiling detection, and the other state is set as no boiling detection, it is possible to detect whether boiling is detected at the contact or not. It is possible to memorize the state without overflowing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit block diagram of a control device for an electric water heater according to the present invention. In the figure, temperature detection means 1 detects the water temperature at the lower part of the hot water storage tank (not shown) of the electric water heater, hot water temperature setting means 2 sets the boiling water temperature desired by the user of the electric water heater, and temperature detection means A peak shift calculating means 3 calculates a peak shift time based on the pre-boiling water temperature detected in step 1 and the boiling water temperature set by the hot water temperature setting means 2. Then, after the peak shift time calculated by the peak shift calculating means 3 has elapsed after the midnight power supply started, the heater is turned on, and the temperature detected by the temperature detecting means 1 rises to the temperature set by the hot water temperature setting means 2. temperature control means 4 which turns off the heater and outputs the output to the storage means 6;
A heater 5 that heats the water in the hot water storage tank, a storage unit 6 that stores the state of whether or not the temperature control unit 4 has detected boiling, and a storage unit 6 when power supply starts late at night.
It is constituted by a memory determination means 7 and the like for determining the state of the memory.

The operation of the electric water heater control device constructed as above will be explained with reference to FIG. 2. FIG. 2 is an operation flowchart of the electric water heater control device of the present invention.

First, the operation when there is no power outage during the late-night power supply period will be described. As a condition, it is assumed that there was no power outage during the late-night power supply period on the previous day, and the water in the hot water storage tank was boiled to the temperature set by the hot water temperature setting means 2. First, when power supply of late-night power is started, in step 1, the memory determining means 7 inputs the state of the memory means 6. The storage means 6 stores the previous day's boiling state. In step 2, the storage state determination result is determined, and since the boiling state is stored, the process proceeds to step 3. In step 3, since the memory determining means 7 has already determined the memory state of the memory means 6 at the time of starting power supply on the previous day,
Today I will remember that there is no boiling because the state is reset. In other words, this state memory of no boiling is to remember that boiling has not been completed after today's late-night electricity supply started. Then, in step 4, the peak shift is performed by the peak shift time calculated by the peak shift calculation means 3 based on the water temperature before boiling detected by the temperature detection means 1 and the boiling temperature data set by the hot water temperature setting means 2. It will be done. After the peak shift time has elapsed, the process proceeds to step 5, where the temperature control means 4 starts energizing the heater. In step 6, the temperature control means 4 compares the water temperature in the hot water storage tank detected by the temperature detection means 1 with the boiling water temperature set by the hot water temperature setting means 2, and if the water is boiled, the process proceeds to step 7. In step 7, the temperature control means 4 stops energizing the heater, and in step 8, the storage means 6 stores the signal output from the temperature control means 4 indicating that there is boiling. Therefore, at the end of the late-night power supply, the storage means 6 will have stored the boiling state. Furthermore, a similar operation is performed to perform a peak shift when power supply starts at midnight on the next day.

Next, the operation when a power outage occurs during the late-night power supply period will be explained. As a condition, it is assumed that there was no power outage during the late-night power supply period on the previous day, and the water in the hot water storage tank was boiled to the temperature set by the hot water temperature setting means 2. First, when the power supply of late-night power is started, in step 1, the memory determining means 7 inputs the state of the memory means. The storage means 6 stores the previous day's boiling state. In step 2, the storage state determination result is determined, and since the boiling state is stored, the process proceeds to step 3. In step 3, since the storage determination means 7 has already determined the storage state of the storage means 6 at the time of starting power supply on the previous day, it stores "no boiling up" today in order to reset the state. This state storage of no boiling is to remember that boiling has not been completed after today's late-night power supply started. Then, in step 4, the peak shift is performed by the peak shift time calculated by the peak shift calculation means 3 based on the water temperature before boiling detected by the temperature detection means 1 and the boiling temperature data set by the hot water temperature setting means 2. It will be done.

If a power outage occurs in this peak-shifted state, the storage means 6 will have stored the no-boiling state stored in step 3, so if the power is restored from the power outage in this state, the power supply will be interrupted. Since the process has started, the process starts from step 1 in the flowchart of FIG. In step 1, the memory determining means 7 inputs the state of the memory means. The storage means 6 stores the state of no boiling. In step 2, the determination result of the storage state is determined, and since the state of no boiling is stored, the process proceeds to step 9 and the peak shift is canceled. Next, the process proceeds to step 5, where energization of the heater is started. The operations after step 6 are as explained at the beginning. In this way, if a power outage occurs during late-night power supply hours before the electric water heater reaches boiling point, the peak shift will be canceled.
The heater is energized immediately.

As described above, the boiling signal from the temperature control means 4 is stored in the storage means 6, and the storage determination means 7 determines the state of the storage means 6 at the time of starting power supply, thereby starting the current power supply. It is possible to determine whether power has started running late at night or has returned from a power outage. Then, at the start of power supply, the memory determining means 7 determines the state of the memory means 6, and if the stored state is "boiling", a peak shift is performed to eliminate the peak of late-night power demand and reduce heat radiation loss from the electric water heater. . If the stored state is no boiling, the peak shift is canceled as a recovery from a power outage and heater energization is started immediately, so there is no possibility that the peak shift time will be lengthened and boiling will not occur due to a power outage.

Furthermore, since all of the above operations are memorized while power is being supplied during the late night power hours, there is no need for backup in the event of a power outage or for power outage detection means using a charging/discharging circuit. Naturally, a 100V power supply is not required either.

Furthermore, the data to be stored in the storage means 6 can be a simple storage means, since the data may be two values, ie, with boiling and without boiling. Note that since the stored data is two values, data processing is reliable and connection with a digital circuit represented by a microcomputer is easy.

The embodiment shown in FIG. 3 is a circuit diagram of a storage means in which the storage means 6 of FIG. 1 is constructed of a self-holding relay. 8 is a self-holding relay, also called a latching relay.
The contact state can be maintained simply by applying pulse input. 9 is a set coil of the self-holding relay 8, and 10 is a reset coil. Reference numeral 11 indicates a contact point of the self-holding relay 8. Here, the set-side contact corresponds to the boiling-up detection state, and the reset-side contact corresponds to the boiling-up detection state. 12 is a transistor that drives the set coil 9;
3 is a transistor that drives the reset coil 10. Reference numeral 14 indicates a boiling detection memory terminal that connects the base of the transistor 12 and the temperature control means 4, 15 indicates a boiling detection non-memory terminal that connects the base of the transistor 13 and the memory determining means 7, and 16 indicates the contact 11 and the memory determining means. 7
This is a memory output terminal for connecting.

The operation of the storage means 6 configured as above will be explained. If no boiling is to be stored in step 3 of the operation flowchart in FIG.
The transistor 13 is driven and the reset coil 10 is energized. Therefore, the contact 11 becomes the reset side, and the L level, that is, no boiling detected, is output to the memory output terminal 16. If boiling is to be stored in step 8 of the operation flowchart of FIG. 2, the output pulse of the temperature control means 4 drives the transistor 12 through the boiling detected memory terminal 14, and the set coil 9 is energized. Therefore, the contact 11 becomes the set side and the memory output terminal 16
The H level, that is, boiling is detected, is output.

As described above, by configuring the storage means 6 with the self-holding type relay 8, it is possible to memorize either two states, ie, with boiling detection and without boiling detection, even when power is not supplied, using a simple circuit. can,
It is possible to provide an inexpensive control device for an electric water heater.

[0024]The temperature detection means 1, the hot water temperature setting means 2,
It goes without saying that the peak shift calculation means 3, the temperature control means 4, and the memory determination means 7 can be constructed using a microcomputer.

In addition to the self-holding relay 8, the storage means 6 may also utilize a storage element such as a rewritable memory.

[0026]

As described above, the present invention stores the boiling signal from the temperature control means in the storage means, and the storage determination means determines the state of the storage means at the time of starting power supply. It is possible to determine whether the start is from the start of late-night power supply or from recovery from a power outage. If the memory state is "boiling", peak shift is performed to eliminate the peak of late-night electricity demand and reducing heat radiation loss from the electric water heater, and if the memory state is "no boiling", it is used as a recovery from a power outage. Since the peak shift is canceled and the heater energization is started immediately, there is no possibility that the peak shift time will become longer due to a power outage and the boiling will not occur.

[0027] Furthermore, since all of the above operations are performed while power is being supplied during the late-night power hours, there is no need for backup in the event of a power outage or for power outage detection means using a charging/discharging circuit. Naturally, a 100V power supply is also not required. In addition, the data stored in the storage means is
Since only two values, ie, boiling and no boiling, can be used, a simple storage method is sufficient.

Furthermore, since the stored data is binary, data processing is reliable and connection with digital circuits typified by microcomputers is easy.

Further, in the present invention, the storage means is configured with a self-holding relay in which one state of the open/closed contact state is set to indicate boiling-up detection, and the other state is set to non-boiling-up detection, so that power is not supplied. The storage of any two states, ie, with boiling detection and without boiling detection, can be configured with a simple circuit, and an inexpensive control device for an electric water heater can be provided.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of a control device for an electric water heater according to an embodiment of the present invention.

FIG. 2: Operation flowchart of the electric water heater control device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram of a storage means of a control device for an electric water heater according to an embodiment of the present invention.

[Explanation of symbols]

1 Temperature detection means 2. Water temperature setting means 3 Peak shift calculation means 4 Temperature control means 6 Memory means 7 Memory determination means

Claims (2)

[Claims] Claims: 1. Temperature detection means for detecting the temperature in a hot water storage tank; hot water temperature setting means for setting the boiling water temperature; and temperature data obtained by the temperature detection means and the hot water temperature setting means. peak shift calculation means for delaying the start of heater energization;
temperature control means for stopping energization of the heater when the temperature in the hot water storage tank rises to the temperature set by the hot water temperature setting means after the start of energization of the heater; and a storage means for storing the fact that the temperature control means has detected boiling. A control device for an electric water heater, comprising: memory determination means for canceling the peak shift time calculated by the peak shift calculation means when boiling detection is not stored in the storage means at the time of starting power supply. 2. The electric hot water according to claim 1, wherein the storage means is constituted by a self-holding relay in which one of the open and closed states of the contact indicates that boiling is detected and the other state indicates that boiling is not detected. device control device.