JPS647302B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a control device for a hot water storage type electric water heater that uses late-night electricity, and is based on the user's hot water usage record and the next day's hot water boiling pattern input from an input device. Conventionally, the required amount of heat to be stored in the hot water storage tank was calculated using
The purpose of this system is to allow users to use the fixed capacity of electric water heaters according to their needs, as well as to control multiple electric water heaters in a uniform manner using a central control unit. .

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 power, which is generally turned on around 23:00.
8 hours from 7:00 to 7:00 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 that heat loss due to natural heat radiation from the hot water storage tank 1 and heat radiation from hot water stagnant in the pipes increases. It was hot. Additionally, since each machine was heated up in a short period of time, there was a problem in that the load was concentrated in the first half of the night when the power was on.

This invention attempts to eliminate these drawbacks, and stores the actual amount of hot water used in a storage device as data, for example, the actual amount of heat used for the amount of hot water used over the past few days, and this data is updated every day with the actual amount of hot water used for that day. The amount of remaining hot water is updated by replacing the oldest data, that is, it has a learning function, and the amount of remaining hot water is controlled by controlling the power supply to the heating element so that the required amount of mixed hot water is always obtained based on this data. This is to reduce heat loss after boiling and to eliminate as much as possible the heat loss after boiling. In this invention, a plurality of hot water storage type electric water heaters are managed by a central control device, and the start time of energization is distributed so that the load is evenly distributed throughout the late-night power supply period. be.

Fig. 3 shows the configuration of a hot water storage type electric water heater which is the object of control of the present invention, with reference numerals 1 to 5, 7, and 8.
shows the same thing as FIGS. 1 and 2. 9 is a temperature detection means (hereinafter referred to as a temperature sensor) such as a thermistor, which continuously detects the temperature of the water supplied from the water supply pipe 2 into the hot water storage tank 1, and also detects the temperature of boiling water. Yes, it is located 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 a switch for controlling the supply of electricity to the heating element 5, which is opened and closed by operation of a control section to be described later. Reference numeral 11 denotes the above-mentioned control unit, which includes a storage device 12, a required heat amount setting device 13, a boiling temperature setting device 14, an energization control device 15, and a usage amount calculation device 16. A water meter 17 is attached to the water supply pipe 2 and indirectly measures the flow rate of hot water flowing out from the hot water storage tank 1. For this purpose, for example, an encoder is attached to a metering propeller that rotates according to the flow rate, and generates the number of pulses according to the flow rate. Note that the water meter 17 may be provided on the hot water supply pipe 3 side. Further, 18 is an input device.

The storage device 12 stores the amount of heat used for the amount of hot water calculated by the amount of heat used calculation device 16, and the performance K _G for the past several days as data. This data is set to a fixed number of days, such as 10 days, so that the latest data from the previous day is always stored and the oldest data is deleted one by one.

The required heat amount setting device 13 is, for example, a storage device 12.
to the data stored within it (in the example above
Call the maximum value K _G max (within 10 days) and calculate the constant C (for example, 1.1 if the margin rate is 10%) and look at the margin rate.
) to calculate the required amount of heat Ks (kcal) to be stored in the hot water storage tank 1 as Ks=K _G max×C.

The boiling temperature setting device 14 sets the required amount of heat Ks
(kcal), hot water storage tank capacity Vt (), water supply temperature Ti
(°C), calculate the boiling temperature To (°C) using the formula below.

To=Ks/Vt+Ti The energization control device 15 controls the on/off of the switch 10. It is turned on by a command from the central control device, which will be described later, and the temperature sensor 9 rises to the temperature.
Turns off when To is detected.

The amount of heat used calculation device 16 calculates the amount of heat required for the previous day, assuming that the amount of hot water used by the water meter 17 is v (), the temperature of the supplied water is Ti (℃), and the previous day's boiling temperature is To (℃).
K _G is calculated as K _G =v×(To−Ti).

The input device 18 may be used to input, for example, "take a bath" or the like.
The user selects a boiling pattern for the next day, such as "no bathing", from pre-prepared boiling patterns.

FIG. 4 is a block diagram of the overall configuration showing one embodiment of the present invention. In this figure, 100A, 100
B, . . . 100N indicates the above-mentioned hot water storage type electric water heater according to the present invention, and inside the control unit 11, only the boiling temperature setting device 14 and the energization control device 15 necessary for explanation are shown, and the others are omitted. There is. 20
0 is a central control unit, each hot water storage type electric water heater 100
Data on the boiling temperature is received from the boiling temperature setting device 14 of A to 100N, and the respective energization start times are distributed so that the load is evenly distributed throughout the late night power supply time period. There are various ways to level the water, but a simple way is to turn on and off each hot water storage type electric water heater in order, starting with the one with the highest boiling temperature. In short, the central control device 200 issues a control command to each energization control device 15 so that the peak is leveled and the load approaches a uniform load.

Next, the operation of the above embodiment will be explained with reference to FIG. Note that (1) to (13) in FIG. 5 represent each step.

It starts (1), and at midnight, for example, 23:00, the time switch 8 is turned on (2). When control starts at the same time as this power supply, first, the daily hot water usage record,
That is, before midnight electricity is supplied to the electric water heater, the amount of heat K _G used for the amount of hot water used that day is determined by the amount of heat used calculation device 16 (3), and this data is stored in the storage device 12 as the latest data. The input data is replaced with the oldest data among the data previously stored in the storage device 12, and the data is updated (4). Next, the largest K _G max of the latest data is called from the storage device 12 (5),
In the required heat amount setting device 13, the required heat amount Ks is set by multiplying K _G max by a constant C based on the margin rate.
(6). Moreover, in the boiling temperature setting device 14,
The temperature of the water supply in the hot water storage tank 1 is determined by the temperature sensor 9.
Measure Ti (7) and set the boiling temperature To from the hot water storage tank capacity Vt (8).

In this way, when the boiling temperature To set for each water heater is input to the central control device 200, the central control device 200
Based on this, the energization control device 15 of each water heater is configured so that the load is distributed evenly throughout the late night power supply period.
Sends a signal to start energizing. In this way, upon receiving a signal to start energization, each of them starts energizing the heating element 5 (9). Then, the temperature of the water reaches its boiling point.
When To is reached (10), the power to the heating element 5 is turned off (11).

Then, the midnight power supply time end time, for example, 7
When the time comes, time switch 8 turns off (12),
The sequence is stopped (13).

In addition, in the above embodiment, the required heat amount setting device 13
Although the maximum K _G max among the data in the storage device 12 was used to calculate the required heat amount Ks, the average over a fixed number of days or other data may also be used. Furthermore, a microcomputer equipped with a central processing unit (CPU) can be used as the control unit 11.

Further, in the above embodiment, each hot water storage type electric water heater was controlled to be energized in order from the one with the highest boiling temperature, but the present invention is not limited to this.
A plurality of units may be energized at the same time, and the point is that the power consumption may be leveled as much as possible in the end.

As explained in detail above, the present invention stores the latest data on the amount of heat used in relation to the amount of hot water used as the results for the past several days in the storage device, and uses this data and the boiling water data for the next day inputted from the input device. Since the required amount of heat stored in the hot water storage tank and the boiling temperature are set based on the heating pattern, the amount of hot water corresponding to the user's actual situation can be obtained every day, and the amount of remaining hot water can be reduced by using the input device. Therefore, heat radiation loss after boiling is reduced and maintenance costs are reduced. Furthermore, the central control unit allocates the start time of energizing multiple hot water storage type electric water heaters according to their boiling temperatures so that the load is evenly distributed throughout the late night power supply period. It has the advantage of increasing efficiency.

[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 a block diagram showing an embodiment of the present invention, and FIG. 4 is a block diagram showing the overall structure of an embodiment of the present invention. FIG. 5 is also a control flowchart. 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 a switch, and 11 is a control unit , 12 is a storage device, 13 is a required heat amount setting device, 14 is a boiling temperature setting device, 1
5 is an energization control device, 16 is a used heat amount calculation device, 1
7 is a water meter, 18 is an input device, 100A to 100
N is a hot water storage type electric water heater, and 200 is a central control device. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A heating element that heats the water in the hot water storage tank using late-night electricity, a temperature detection means that detects the temperature of water supplied to the hot water storage tank and the boiling temperature, and an input that inputs the boiling pattern of the next day's water. a storage device that stores the actual amount of heat used for the amount of hot water used over the past several days as data; a required amount of heat setting device that sets the amount of required amount of heat to be stored in the hot water storage tank based on the data; a boiling temperature setting device that sets a boiling temperature based on the water supply temperature, required heat amount, and hot water storage tank capacity; and a boiling temperature setting device that sets the boiling temperature based on the water supply temperature, the required amount of heat, and the hot water storage tank capacity; an energization control device that stops energizing the heating element when the boiling temperature set in is reached; A group of multiple hot water storage type electric water heaters each equipped with a heat consumption calculation device that updates the data by replacing the oldest data stored in the storage device. A hot water storage type electric water heater characterized by being equipped with a central control device that distributes the start of energization according to the boiling temperature so that the power supplied to the water heater is distributed evenly over the entire late night power supply time period. control device.