JPS6030928A - Control device for hot water storage type electric water heater - Google Patents

Abstract

PURPOSE:To enable a use of capability of hot water storage type electric heater in correspondense with the actual requirement of a user by a method wherein a required energization of electric power is calculated in response to the use of hot water at the user. CONSTITUTION:An energization control device 14 controls an electric power for a heater 5 in such a way as it shown as energization capacity Q(KW) calculated in the calculation device 13. A TRIAC is applied for this unit, for example, and its gate is controlled for its phase. The energization control device 15 performs a control over a turning-OFF (open) of the energization rate control element 10 and is operated when the boiling temperature To calculated by the calculator device 13 is detected by the temperature sensor 9. The energization power calculation device 16 calculates the time H ranging from a start-up of energization to the turning-OFF of the heater 5 and the energization capacity Q(KW) to get the energization power WG=HXQ(KWH) and then inputs it to the memory device 12.

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 energized electricity based on the user's actual hot water usage. The aim is to allow users to use the previously fixed capacity of storage type electric water heaters according to their needs.

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 midnight power supply start time comes, the contact of the time switch 8 is closed and the power supply to the heating element 5-1 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 hot 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 reaches 85°C every morning.

In this way, 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 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°C. The formula for calculating the amount of mixed hot water obtained is as follows.

Now, the hot water storage tank capacity is vt (i), and the boiling temperature inside hot water storage tank 1 is T. ('O), the temperature of the mixed water to be obtained is Tm ('O) + tW=temperature of the water to be mixed (
When Ti ('Ci) is the water supply temperature), the mixed hot water amount Vm
(sentence) can be expressed as .

In this formula, the water supply temperature Ti varies greatly depending on the season. In Tokyo, the temperature ranges from around 5°C in winter to 27°C in summer.
reach the highest level. 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 that the boiling temperature To is 85°C,
The amount of mixed hot water Vm obtained when the water supply temperature T1 is 5°C is 1.6 times that obtained when the water supply temperature T1 is 27°C.

On the other hand, the amount of hot water used is approximately constant throughout the year, or in fact, the actual amount used generally decreases 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 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 storage device stores the usage history of hot water, for example, data on the amount of hot water used in the past 10 days, and this data is updated every day based on the amount of hot water used that day. In order to always obtain the amount of mixed hot water of By doing so, the amount of remaining hot water is reduced and heat loss after boiling is eliminated as much as possible.

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. S3, 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 an energization rate control element such as a triac for controlling the energization rate to the heating element 5, and is controlled by a control section to be described later. 11 is the above-mentioned control unit, and the storage device 12
．． Arithmetic device 139 Energization rate control device 149 Energization control device 1
5. and an energization power amount calculation device 16.

The storage device 12 stores, as data, the performance WG of the energized power amount for several days by the energized power amount calculation device 16.

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, for example, calls the maximum value WGmax from the data stored therein (within 10 days in the above example) from the storage device 12, and calculates a constant C based on the margin rate (for example, a margin rate of 10%). 1.1) to calculate the required amount of energized power Ws (KWH) as Ws = WGmaxXC (KWH).

In addition, the current carrying capacity Q (KW) of the heating element 5 is calculated by the calculation device 13.
Set with . In other words, the late-night power supply period is 8 hours, so

Furthermore, the arithmetic unit 13 calculates the hot water storage tank capacity Vt (text),
The required energizing power amount Ws (KWH) and the water supply temperature Ti
From ('O), the boiling temperature Tc.

(°C) from the formula below.

The energization rate control device 74 controls the energization capacity Q determined by the calculation device 73.
(KW).The electric power to the heating element 5 is controlled so that

This is accomplished by using, for example, a triac and controlling the phase of its gate.

The energization control device 15 turns off (opens) the energization rate control element 10.
It is activated when the temperature sensor 9 detects the boiling temperature T(, ) stored by the arithmetic unit 13.

The energization power amount calculation device 16 calculates the time H from the start of energization until the heating element 5 is turned off, and the energization sound iQ (KW).
Calculate the energized energy WG = HXQ (KWH) from
This is input to the storage device 12.

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.

The time switch 8 is turned on at midnight, for example at 23:00 (2). First, the maximum energized power JiWGmax among the latest data is called from the storage device 12 (3).

Next, in the arithmetic unit 13, WGmax is multiplied by a constant C based on the margin rate to determine the energized power amount W s (K W H), and further divided by 8 to calculate the energized capacity Q (KW) ( 4). Furthermore, the temperature T] of the water supply in the hot water storage tank 1 is measured by the temperature sensor 9 (5). Furthermore, the arithmetic device 1
3. Calculate the boiling temperature To from the energized power amount Ws (KWH), the water supply temperature Ti, and the hot water storage tank capacity Vt6.
), 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, if the water temperature reaches To by the temperature sensor 9 (8), the heating element 5
3), and calculate the actual value WG (KWH) of the amount of energized power from the time from the start of energization to the stop of energization (lO). Then, the energized actual value WG (KWH
) to the storage device 12 to update the data (11)
.

Furthermore, at the end of the late night power supply time, for example 7 o'clock, the time switch 8 is turned off (12) and the power supply is stopped (13).

In addition, in the above embodiment, the current carrying capacity Q(
KW), the maximum W among the data in the storage device 12 is used to calculate
Although Gmax is used, an average over a fixed number of days or other data may also be used. In addition, the control unit 11
A microcomputer equipped with a central processing unit (CPU) can be used as the computer.

As explained in detail above, the present invention stores the latest data on energization time as past results in a storage device, and determines the required amount of power to energize the heating element based on this data, and Since the power supply is leveled over the entire late-night power supply rate, the amount of hot water that can be obtained every day according to the actual situation of the user is reduced, and the amount of remaining hot water is reduced. This has the advantage of reducing losses, lowering maintenance costs, and leveling out late-night power loads.

[Brief explanation of the drawing]

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, and Figure 3 is a diagram of the main electrical circuit diagram of a conventional hot water storage type electric water heater.
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 an energization rate control element, 11 is a control section, 12 is a storage device, 13 is an arithmetic device, 14 is an energization rate control device, 15 is an energization control device, and 16 is an energization power amount calculation device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 2 Figure 3 Figure 4

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 provided a temperature detection means for detecting the temperature of water supplied to the hot water storage tank and the boiling temperature, and data on the actual energization time. a computing device that calculates the required amount of electricity to be energized to the heating element based on the data, and calculates the boiling water temperature from the amount of energized electricity per water supply temperature and the capacity of the hot water storage tank; an energization rate control device that controls the power supplied to the heating element so that the amount of power supplied to the heating element matches the required amount of energized power determined by the arithmetic unit between the start and end of supply of late-night power; , an energization control device that stops energizing the heating element when the boiling temperature detected by the temperature detection means reaches the boiling temperature calculated by the arithmetic unit; 1. A control device for a hot water storage type electric water heater, comprising: a energization power amount calculation device that calculates and inputs the value into the storage device to update the data.