JPS6030940A - Control device of hot-water storage type electric hot- water heater - Google Patents

Abstract

PURPOSE:To contrive to utilize the performance of the titled hot-water heater according to the actual requirement of user by a method wherein the necessary amount of heat required to be stored in a hot-water storage tank is calculated based on the actual amount of the hot-water consumed by the user. CONSTITUTION:A memory device 12 stores the data KG as the actual consumption of the total amount of heat for several days for the consumed amount of hot-water calculated with a consumed amount of heat calculating device 15. The data is calculated and stored, for instance, for ten days as the constant number of days, moreover, the stored data is ketp at up-to-date. A calculating device 13 calls the maximum value KGmax from among the stored data in the memory device 12 (among the data for ten days in above example), mutiplies the constant C including the allowance (for instance, multiplies 1, 1 at the 10% margin), calculates the necessary amount of heat KS (kcal) required for storing in a hot-water storage tank 1 by the formula KS=KGmaxXC.

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 calculates the required amount of heat to be stored in a hot water storage tank based on the user's actual hot water usage. In this way, the purpose is to make it possible to use the capacity of a hot water storage type electric water heater, which has conventionally been fixed, 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, and 3 is a hot water storage tank.
is a hot water 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 from 11:00 p.m. to 7:00 the next morning. No. 8
It's time.

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. When the temperature of the hot water in the hot water storage tank 1 reaches 85° C., the contacts of the automatic temperature regulator 6 are opened and the power supply to the heating element 5 is stopped. Thereafter, the temperature of the water is maintained at 85°C by opening and closing the automatic temperature controller 6, and in this way, the entire amount of stored hot water is boiled to 85°C every morning.

In this manner, in order to increase hot water storage efficiency, the hot water storage type electric water heater has a structure in which the boiling temperature is set as high as possible, and heating stops when the set temperature is reached. However, users do not leave hot water unused, but mix it with water and use it as a mixed hot water at around 40 to 45°C. The formula for calculating the amount of mixed hot water obtained is as follows.

Now, the hot water storage tank capacity is vt l), the boiling temperature in hot water storage tank 1 is ro (°O), and the temperature of the mixed hot water to be obtained is Tffl (°c) + 1 m water temperature (water supply temperature ) is Ti ('O), the amount of mixed hot water V
m (sentence) can be expressed as.

In this formula, the water supply temperature T i varies greatly depending on the season. In Tokyo, the temperature ranges from around 5°C in winter to 27°C in summer.
It reaches C position. 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, assuming 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 generally constant throughout the year, or in fact, the actual amount used is lower in the summer because hot water is used at a lower temperature, and the amount of hot water remaining in the summer is lower than in the winter. There will be more.

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 every day.

In this way, if the water supply temperature is high or 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. was there.

This invention attempts to eliminate these drawbacks.
The amount of hot water used, for example, the amount of hot water used in the past 10 days, is stored in the storage device as heat amount data, and this data is stored every day.
It is updated based on the amount of hot water used that day, that is, it has a learning function.Based on this data, the required time for energizing the heating element is calculated so that the required amount of mixed hot water is always obtained, and the power to the heating element is updated. By controlling the supply so that it is leveled over the entire period from the start of the late-night electricity supply until the end of the supply, the amount of remaining hot water is reduced and heat loss after boiling is eliminated as much as possible. be.

An embodiment of the present invention will be described below with reference to the overall configuration diagram in Fig. 3 and Fig. 4.
The explanation will be based on the control flowchart shown in the figure.

In FIG. 3, numerals 1 to 5, 7, and 8 indicate the same parts as in 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 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 electricity supply to the heating element 5, which in this example closes when the time switch 8 is turned on;
It is opened by operating the control section, which will be described later. Reference numeral 11 denotes the above-mentioned control unit, which includes a storage device 12. Arithmetic device 131 energization rate control device 14. It consists of a used heat amount calculation device 15 and an energization control device 16. Reference numeral 17 denotes a water meter installed in the water supply pipe 2, which measures the flow rate of water supplied to the hot water storage tank 1. For this purpose, for example, an encoder is attached to a metering propeller that rotates in accordance with the flow rate to generate a number of pulses in accordance with the flow rate. Note that the water meter 17 may be provided on the hot water supply pipe 3 side.

The storage device 12 stores the heat value of the amount of hot water used calculated by the heat use amount calculating device 15, and the actual performance KG for several days as data. This data is set to a fixed number of days, such as 10 days, so that the latest data is always saved.

The arithmetic unit 13 calls the maximum value K Gmaz of the data stored in the storage device 12 (in the above example, within 10 days), and calculates a constant C (for example, a margin rate of 10%) based on the margin rate. In the case of , it becomes 1.1).
The required amount of heat stored in the hot water storage tank 1 Ks (kcal
) is calculated as Ks = KGmaxX C .

Furthermore, the calculation device 13 has a hot water storage tank capacity Vt (J),
Required amount of heat KS (1 (cal), and water supply temperature T
From i (°C), calculate the boiling temperature To ('c) using the following formula.

Furthermore, the arithmetic unit 13 calculates the energizing power Q (KW) of the heating element 5.
Set. In other words, since the late-night power supply time period is 8 hours, it becomes as follows.

The energization rate control device 14 controls the energization power Q determined by the arithmetic device 13.
(KW), the power to the heating element 5 is controlled. This can be done, for example, by using a triac and controlling the phase of its gate. If the boiling temperature of is TO (°C), then the required amount of heat KG for the previous day is determined as KG = vX (To-Ti).

The energization control device 16 is configured so that the temperature detected by the temperature sensor 9 is
The switch 10 is turned off when the boiling temperature TO is reached.

Next, the operation of the embodiment shown in FIG. 3 will be explained with reference to FIG. 4. Note that (1) to (14) in FIG. 4 represent each step.

1) At the end of the day's use of hot water, that is, before midnight power is supplied to the electric water heater, the amount of heat KG for the amount of hot water used that day is calculated by the amount of heat used calculation device 15.
(2), this data is input to the storage device 12, and the previously stored data is updated (
3).

Therefore, at midnight, for example at 23:00, the time switch 8 is turned on (4). When control is started at the same time as this energization, first, the largest one of the latest data K Gmax is called from the storage device 12 5), and the arithmetic device 13
In this step, the required amount of heat Ks is set by multiplying KGmax by a constant C based on the margin rate (6). At the same time, the temperature sensor 9 measures the water supply temperature Ti in the hot water storage tank 1 (7), and furthermore, the arithmetic unit 13 measures the energizing power Q (K
W), then energization time Hs, water supply temperature Ti,
The boiling temperature To is calculated and set from the hot water storage tank capacity vt and the required amount of heat Ks (8).

When the data of the energized power Q (KW) obtained in this way is inputted to the energization rate control device 14, the average power per unit time supplied to the heating element 5 during the late-night power supply time is calculated and energized. The rate is determined (8) and the heating element 5 is energized (10). And the boiling temperature T is set in advance. (11), the energization control device 1
6 operates to turn off the switch 10 and turn off the power to the heating element 5 (12).

Furthermore, at the end of the midnight power supply time, for example 7 o'clock, the time switch 8 is turned off (13) and the sequence is stopped (14).

In the above embodiment, the calculation unit] 3 calculates the required amount of heat Ks using the maximum K Gma of the data in the storage device 12.
Although x is used, an average over a fixed number of days or other data may be used. Furthermore, a microcomputer equipped with a central processing unit (CPU) may be used as the control unit 11.

As explained in detail above, the present invention stores the latest data on the amount of heat for the amount of hot water used as past results in the storage device, and determines the amount of power to be supplied to one heating element based on this data. In addition, by equalizing the power supply throughout the late-night power supply band,
Since the amount of hot water corresponding to the user's actual situation can be obtained every day, the amount of remaining hot water is reduced, which has the advantage of reducing heat radiation loss after boiling and reducing maintenance costs.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a general hot water storage type electric water heater, Figure 2 is a main electrical circuit diagram of a conventional hot water storage type electric water heater, $3
This figure is an overall configuration diagram showing one embodiment of the present invention, and FIG. 4 similarly shows its 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, 11 is a control unit, 12
is a storage device, 13 is an arithmetic device, 14 is an energization rate control device,
Reference numeral 15 is a used heat amount calculation device, 16 is an energization control device, and 17 is a water meter. Note that the same reference numerals in the figures indicate the same or equivalent subdivisions. Agent Masu Oiwa! (2 others)

Claims (1)

[Claims] In an electric water heater that heats water in a hot water storage tank by energizing a heating element using late-night electricity, there is a temperature detection means for detecting the temperature of water supplied to the hot water storage tank and the boiling temperature, and a heat value that measures the actual amount of hot water used. a storage device that stores the data as data; a calculation device that calculates the required amount of heat to be stored in the hot water storage tank and the power to be applied to the heating element based on the data; The present invention is characterized by comprising an energization rate control device for supplying electricity on average, and a used heat amount calculation device that calculates the used heat amount and inputs the value into the storage device to update the data. Control device for hot water storage type electric water heater.