JPS647295B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for a hot water storage type electric water heater that uses late-night electricity, and the present invention is based on the user's hot water usage performance and the next day's hot water boiling pattern input from an input device. The purpose of this invention is to calculate the required amount of energized power based on the system, so that the capacity of a hot water storage type electric water heater, which has conventionally been fixed, can be used in accordance with the actual situation of the user.

FIG. 1 is a block diagram of a general hot water storage type electric water heater, and FIG. 2 is a main electrical circuit diagram of a conventional hot water storage type electric water heater.

In these figures, 1 is a hot water storage tank, 2 is a water supply pipe, 3 is a hot water supply pipe, 4 is a hot water tap, 5 is a heating element, 6
is an automatic temperature controller, 7 is a power supply, and 8 is a time switch for late-night electricity, whose power consumption range is generally
It is 8 hours from 11pm to 7am the next morning.

Next, the operation of the conventional example having the above configuration will be explained. When the time to start supplying late-night power comes, the contact of the time switch 8 is closed and the supply of electricity to the heating element 5 is started. And the water temperature in hot water storage tank 1 is 85℃.
When this happens, the contacts of the automatic temperature regulator 6 are opened and the power supply to the heating element 5 is stopped. Thereafter, the water temperature is maintained at 85°C by opening and closing the automatic temperature controller 6, and in this way, the entire stored hot water is heated to 85°C every morning.

In this way, in order to increase the efficiency of hot water storage, electric hot water heaters are designed to set the boiling temperature as high as possible, and stop heating when the set temperature is reached. However, users do not use high-temperature hot water as it is, but mix it with water and use it as a mixed hot water at around 40 to 45 degrees Celsius. The formula for determining the amount of mixed hot water obtained is as follows.

Now, the hot water storage tank capacity is Vt (), hot water storage tank 1
If the boiling temperature in the water is To (℃), the temperature of the mixed water to be obtained is Tm (℃), and the temperature of the water to be mixed (water supply temperature) is Ti (℃), the mixed hot water volume Vm ()
can be expressed as Vm=Vt×To−Ti/Tm−Ti().

In this formula, the water supply temperature Ti varies greatly depending on the season. In Tokyo, temperatures range from around 5°C in winter to around 27°C in summer. Therefore, the amount of hot water that can be obtained as mixed hot water at an appropriate temperature is small in the winter and large in the summer. That is, when the boiling temperature To is 85°C, the amount of mixed hot water Vm obtained when the water supply temperature Ti is 5°C is 1.6 times that obtained when the water supply temperature Ti is 27°C.

On the other hand, the amount of hot water used is almost constant throughout the year, or rather, the actual amount used is generally lower in the summer because hot water is used at a lower temperature, and the amount of hot water remaining in the summer is larger than in the winter. Furthermore, some users use only 1/2 or 2/3 of the rated amount due to a decrease in the number of family members, leaving a large amount of hot water available each day.

In this way, if the water supply temperature is high and there is residual hot water, the hot water will boil quickly and the hot water will be left unused for a long time.

In this way, leaving unnecessarily high-temperature hot water unused for a long time has the disadvantage of increasing heat loss due to natural heat radiation from the hot water storage tank 1 and heat radiation from hot water stagnant in the pipes. It was hot.

This invention aims to eliminate these drawbacks, and includes an input device for setting the next day's water boiling pattern in advance, step by step, such as "bathing", "not bathing", etc. Based on the past several days' worth of actual data stored in the storage device for each set boiling pattern, the system performs optimal boiling with a reduced amount of remaining hot water, and also supplies power to the heating element late at night. This is intended to eliminate heat loss as much as possible by equalizing the entire time from the start of power supply to the end of power supply.

Hereinafter, one embodiment of the present invention will be described based on the overall configuration diagram in FIG. 3 and the control flowchart in FIG. 4.

In Fig. 3, symbols 1 to 5, 7, and 8 are the first
Figure 2 shows the same thing as Figure 2. 9 is a temperature detection means such as a thermistor (hereinafter referred to as a temperature sensor);
It continuously detects the temperature of water supplied into the hot water storage tank 1 from the water supply pipe 2, and also detects the temperature of boiling hot water, and is provided at the bottom of the hot water storage tank 1. Note that this temperature sensor 9 may be provided separately to detect the temperature of water and the temperature of hot water, respectively. Reference numeral 10 denotes an energization rate control element such as a triax for controlling the energization rate to the heating element 5, which is controlled by a control section to be described later. Reference numeral 11 denotes the above-mentioned control unit, which includes a storage device 12, an arithmetic unit 13, an energization rate control device 14, an energization control device 15, and an energization power amount calculation device 16. 17 is an input device.

The input device 17 may be used to input, for example, "take a bath" or the like.
The next day's boiling pattern, such as "no bathing", is selected from pre-prepared boiling patterns, and the storage device 12 stores the amount of electricity applied for each boiling pattern input into the input device 17. The past several days' worth of energized power amount WG calculated by the calculation device 16 is stored as data. This data is set to a fixed number of days, such as 10 days, so that the latest data for the previous day is always stored and the oldest data is deleted.

The arithmetic device 13 calculates, for example, the maximum value among the data stored in the storage device 12 classified into each pattern (within 10 days in the above example).
WGmax is called and multiplied by a constant C based on the margin rate (for example, 1.1 when the margin rate is 10%) to calculate the required energized power amount Ws (KWH) as Ws=WGmax×C(KWH).

Further, the current carrying capacity Q (KW) of the heating element 5 is calculated by the calculation device 13. In other words, since the late-night power supply period is 8 hours, Q = Ws/8 (KW).

The arithmetic unit 13 calculates the hot water storage tank capacity Vt (), the required energizing power amount Ws (KWH), and the water supply temperature Ti.
(°C), calculate the boiling temperature To (°C) using the formula below.

To=Ws×860/Vt+Ti The energization rate control device 14 controls the energization rate to the heating element 5 using the energization rate control element 10 so that the energization capacity Q (KW) determined by the arithmetic unit 13 is achieved. This is done by using, for example, a triax and controlling the phase of its gate.

The energization control device 15 controls the OFF (opening) of the energization rate control element 10, and is activated when the temperature sensor 9 detects the boiling temperature To determined by the arithmetic device 13.

The energized power amount calculation device 16 calculates the energized power amount WG=H×Q(KWH) from the time H from the start of energization until the heating element 5 is turned off and the energized capacity Q (KW).
is calculated and input into the storage device 12 as the latest data.

The input device 17 is used to input the boiling water pattern for the next day. For example, the amount of hot water used on bathing days and non-bathing days differs greatly, so this can be made into a pattern in advance and inputted the day before.

Next, the operation of the embodiment shown in FIG. 3 will be explained with reference to FIG. 4. Note that (1) to (13) in FIG. 4 represent each step.

It starts (1), and at midnight, for example, 11pm, the time switch 8 is turned on (2). First, storage device 1
2, the maximum amount of energized power WGmax for the corresponding pattern is called out of the latest data stored in the input device 17 classified for each pattern (3).

Next, in the arithmetic unit 13, WGmax is multiplied by a constant C based on the margin rate to calculate the required energized power amount Ws.
(KWH) and further divide by 8 to calculate current carrying capacity Q (KW) (4). In addition, the temperature sensor 9
Measure the water supply temperature Ti in the hot water storage tank 1 by (5). Furthermore, the arithmetic device 13
The boiling temperature To is calculated from Ws (KWH), the water supply temperature Ti, and the hot water storage tank capacity Vt (6), and energization to the heating element 5 is started so that the pre-calculated current carrying capacity Q (KW) is obtained (7) ). On the other hand, when the water temperature reaches To by the temperature sensor 9 (8), the power supply to the heating element 5 is turned off (9), and the actual value WG of the energized power amount is calculated from the time H from the start of energization to the stop of energization ( KWH) (10). Then, the calculated performance value WG (KWH) is input into the storage device 12 as the latest data, and at the same time, the oldest data from among the data stored so far is deleted to update the data (11).

Furthermore, the late-night power supply time end time, for example, 7
When the time comes, time switch 8 turns off (12),
Stop (13).

In the above embodiment, the maximum WGmax of the data in the storage device 12 is used to calculate the current carrying capacity Q (KW) in the arithmetic unit 13, but in addition, the average over a fixed number of days may be used, Other data may also be used. Furthermore, a microcomputer equipped with a central processing unit (CPU) can be used as the control unit 11.

As explained in detail above, the present invention allows the user to input a water boiling pattern using an input device, and for each boiling pattern, the latest data of the amount of electricity supplied for several days is stored in the storage device as past results. is memorized and the required amount of electricity to be applied to the heating element is determined based on this data, and the power supply is leveled over the entire late night power supply time period. Since the amount of hot water that is available every day is based on the user's actual situation, the amount of remaining hot water is smaller compared to those without an input device, which reduces heat loss after boiling and reduces maintenance costs. It has the advantage of leveling out late-night power loads.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a typical hot water storage type electric water heater.
FIG. 2 is a main electrical circuit diagram of a conventional hot water storage type electric water heater, FIG. 3 is an overall configuration diagram showing an embodiment of the present invention, and FIG. 4 is a control flow chart thereof. In the figure, 1 is a hot water storage tank, 2 is a water supply pipe, 3 is a hot water supply pipe, 4 is a hot water tap, 5 is a heating element, 7 is a power supply, 8 is a time switch, 9 is a temperature sensor, 10 is an energization rate control element, 11 12 is a storage device, 13 is an arithmetic device, 14 is an energization rate control device, 15 is an energization control device, 16 is an energization power amount calculation device, and 17 is an input device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In an electric water heater that heats water in a hot water storage tank by energizing a heating element using late-night electricity, a temperature detection means for detecting the temperature of water supplied to the hot water storage tank and the boiling temperature, and a temperature detection means for detecting the boiling temperature of the water the next day. an input device for inputting an increase pattern; a storage device for storing the past few days' worth of energized power as data for each input pattern from the input device; an arithmetic device that calculates the amount of energized electricity and also calculates the boiling water temperature from the water supply temperature, the energized amount of electricity, and the hot water storage tank capacity; and the amount of electricity that is supplied to the heating element between the start and end of supply of late-night electricity. an energization rate control device that controls the energization rate to the heating element so that the amount of electricity matches the required amount of energization power calculated by the arithmetic device; an energization control device that stops energizing the heating element when a rising temperature is reached; and an energization control device that calculates the actual amount of electricity energized to the heating element and inputs the value as the latest data to the storage device; A control device for a hot water storage type electric water heater, comprising a energizing power amount calculation device that causes the device to delete the oldest data from among the data stored in the device and update the data.