JPS6030929A - Control device for hot water storage type electric water heater - Google Patents

Abstract

PURPOSE:To enable a capacity of the titled heater to be used in correspondence with the actual condition of the user by a method wherein a required energization of electric power is calculated on the basis of the actual volume of hot water at the user side and the expected hot water volume for tomorrow to be fed from the input device. CONSTITUTION:An energization rate control element 10 such as a TRIAC for use in controlling the energization rate for a heater 5 is controlled by a control unit 11. The control unit 11 is composed of a memory device 12, calculation device 13, energization rate control device 14, energization control device 15 and energization electric power calculation device 16. The input device 17 is used for selecting the expected use of hot water for tomorrow such as ''bath necessary'' and ''bath unnecessary'' from the predetermined patterns. The memory device 12 stores the actual use record WG of several days of the energization electric power calculated by the energization electric power calculation device 16 as data.

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 is based on the user's actual hot water usage and the next day's expected usage amount input from an input device. The purpose of this system is to calculate the required amount of energized power based on the current amount, thereby allowing the capacity of a hot water storage type electric water heater, which has conventionally been fixed, to 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, and 3 is a hot water storage tank.
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, and the power consumption range is generally from 11:00 p.m. to 7:00 the next morning. It's been 8 hours since then.

Next, the operation of the conventional example having the above configuration will be explained. When the midnight power supply start time arrives, 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 rising temperature is set as high as possible, and heating is stopped 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, let the hot water storage tank capacity be Vt (u), and the boiling temperature in hot water storage tank 1 be T. ('O), the temperature of the mixed hot water to be obtained is Tm ('O), the temperature of the water to be mixed (water supply temperature) is Ti (°O), the amount of mixed hot water 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 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, the boiling temperature T. 85°C, the amount of mixed hot water Vm obtained when the water supply temperature T1 is 27°C is 1.6 times that when the water supply temperature T1 is 5°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, due to a decrease in the number of families, many users use only 1/2 of the rated capacity, or 2/3, 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.
Equipped with an input device for setting the next day's hot water usage status step by step, for example, "to take a bath,""to not take a bath," etc., and past usage stored in the storage device for each set step. Based on the conditions, we perform optimal boiling with a reduced amount of remaining hot water, and level out the power supply to the heating element over the entire time from the start of late-night power supply until the end of power supply, thereby reducing heat. The aim is to eliminate loss 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. 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 that 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 an energization rate control element such as a triac for controlling the energization rate to the heating element 5, which is controlled by a control section described later. Reference numeral 11 denotes the above-mentioned control unit, and storage device] 2
．． Arithmetic calculation 139 Energization rate control device 141 Energization control device 1
5. and an energization power amount calculation device 16. 17 is an input device.

The input device 17 may, for example, say, ``I'm going to take a bath.''

``This is a method for selecting the next day's hot water usage schedule from pre-prepared patterns, such as when not taking a bath.
The t device 12 stores, as data, the actual amount of energized power wG for several days calculated by the energized power amount calculation device υ16 for each pattern input to the input device 17. This data is
For example, the number of days is fixed, such as 1c days, and the latest data is always saved.

The arithmetic unit 13, for example, calls the maximum value WGmax from the data stored in the storage device 12 (in 10 days in the above example), and calculates a constant C (for example, a margin rate of 10%) based on the margin rate. 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.
Calculate with. In other words, since the late-night power supply time period is 8 hours, it becomes Φ.

The calculation device 13 calculates the hot water storage tank capacity Vt (also), the required energizing power amount W s (K W I (), and the water supply temperature T
From i('O), boiling temperature T. Put (0c) into the equation below.

The energization rate control device 14 controls the energization capacity Q determined by the arithmetic device 13.
(KW).The electric power to the heating element 5 is controlled so that

This is done 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 To set 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 capacity Q (KW).
Karadong! , power iwc = HXQ (KWH) is calculated and input to the storage device 12.

The input device 17 is used to input the amount to be used for the next day, and the data in the storage device 12 is thereby updated. for example,
Since the amount of hot water used on bathing days and non-bathing days differs greatly, this is made into a pattern so that it can be entered 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.

When the timer starts (l), the time switch 8 turns on at midnight, for example, 23:00 (2). First, the storage device 12
Among the latest data classified and stored for each pattern of the input device 17, the maximum energized power amount WG of the corresponding pattern
Call max (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 Ti 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 is the rising temperature T from the energized power amount Ws (KWH), the water supply temperature Ti, and the hot water storage tank capacity Vt. Please calculate 6
), 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
8), 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 (10). And the actual value of energized WG (KW)
() is input 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 in the arithmetic unit 13
Although the maximum WGmax among the data in the storage device 12 is used to calculate (KW), an average over a fixed number of days or other data may be used. In addition, the control unit 1
1, a microcomputer equipped with a central processing unit (C, PU) can be used.

As explained in detail above, the present invention allows the user to input the usage pattern using the input device, stores the latest data of the energization time in the storage device as past results for each usage pattern, and based on this data. The amount of electricity required to energize the heating element is determined based on the amount of electricity required to supply electricity to the heating element, and the electricity supply is leveled over the entire late-night electricity supply rate, so the amount of hot water that is matched to the user's actual situation can be obtained every day. Because it is possible to
Compared to a system without an input device, it has the advantage of reducing the amount of residual hot water, reducing heat radiation loss after boiling, 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 unit, 12 is a storage device, 13 is an arithmetic unit, 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 energization rate control device. It is an input device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) 1st M 111 ~ 4 6.1 Fig. 2 6 ``Shutoshita Zs'. Fig. 3 - ] - Operation■ enemy11 4

Claims (1)

[Claims] An electric water heater that uses late-night electricity to energize a heating element to heat water in a hot water storage tank, includes 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 temperature of water supplied to the hot water storage tank and the temperature at which the water is boiled, and the amount of water scheduled to be used on the next day. An input device for inputting data, a storage device for storing the input from the input device and the actual energization time as data, and a storage device that calculates the required amount of energization power to the heating element based on the data, and calculates the amount of power to be energized to the heating element, and calculates the feed water temperature 1. A calculation device that calculates the boiling water temperature from the amount of energized electricity and the capacity of the hot water storage tank, and the amount of electricity supplied to the heating element between the start and end of supply of late-night electricity to the required amount of energized electricity determined by the calculation device. an energization rate control device that controls power supplied to the heating element so as to match; and energization of the heating element when the boiling water temperature detected by the temperature detection means reaches the boiling temperature calculated by the calculation device; and an energization power amount calculation device that calculates the amount of energized power to the heating element and inputs the value into the storage device to update the data. A control device for a hot water storage type electric water heater.