JPH028225B2 - - 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 is based on the user's actual hot water usage and the next day's scheduled usage amount input from an input device. The required energization time to be applied to the heating element is calculated based on the current time, and the start of energization of the heating element is delayed after the midnight power supply start time. The purpose is to allow the ability to be used in accordance with the user's actual situation.

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. For this reason, 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, depending on the user, due to a decrease in the number of family members, etc., the rating may be reduced to 1/2 or 2/2.
I only use 3 or something. Use it in a way that leaves a lot of hot water every day.

As described above, 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.

This invention aims to eliminate these drawbacks, and includes an input device for setting the next day's hot water usage status step by step, for example, ``to take a bath'' or ``not to take a bath.'' Based on the past usage status stored in the storage device for each set stage, the system performs optimal boiling with a reduced amount of remaining hot water, and shifts the energization time to the latter half of the midnight power supply time. The aim is to eliminate heat loss as much as possible.

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 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,
Energization time calculation device 13, boiling temperature setting device 1
4, an energization control device 15, and an energization time measuring 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 hot water usage schedule, such as "no bathing", is selected from pre-prepared patterns, and the storage device 12 records the energization time by the energization time measuring device 16 for each pattern input to the input device 17. The actual HG for several days is stored as data. This data should be stored for a fixed number of days, such as 10 days, so that the latest data is always saved.

The energization time calculation device 13 includes, for example, the storage device 12
Call the maximum value H Gmax of the data stored in it (for 10 days in the above example) and multiply it by a constant C based on the margin rate (for example, if the margin rate is 10%, it will be 1.1). , energizing time Hs (Hr)
is calculated as Hs=H Gmax×C.

The boiling temperature setting device 14 calculates the energization time Hs calculated by the energization time calculating device 13, the hot water storage tank capacity Vt (), the rated power consumption W (kw) of the heating element 5,
From the water supply temperature Ti (°C), calculate the boiling temperature To (°C) using the formula below.

To=Hs×W×860/Vt+Ti The energization control device 15 controls turning off the switch 10. It turns on the switch 10 after (8-Hs) hours from the start time of midnight power supply, and turns off the switch 10 by turning off the temperature sensor. 9 is performed when the boiling temperature To is detected.

The energization time measuring device 16 measures the actual value of the energization time to the heating element 5 and inputs it to the storage device 12, from the time the time switch 8 is turned on until the energization control device 15 turns on the switch 10. Measure the time up to the point of turning off and use it as the energization time.

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 differs greatly between bathing days and non-bathing days, this can be made into a pattern and entered on the previous day. That is, in the storage device 12, performance data for the past 10 days is stored, for example, in a pattern of "taking a bath" and a pattern of "not taking a bath." Therefore, the pattern "to take a bath" is now input. If it is input from the device 17, the performance data for "taking a bath" in the storage device 12 is selected, and among these, for example, the maximum performance data is used to calculate the required energization time as described later.

Next, the operation of the embodiment shown in FIG. 3 will be explained with reference to FIG. 4. Note that (1) to (15) in FIG. 4 represent each step.

It starts (1), and at midnight, for example, 11pm, the time switch 8 is turned on (2). First, the energization time measurement device 16 starts the measurement operation (3), and also calls the maximum value HGmax of the corresponding pattern from the storage device 12 among the latest data classified and stored for each pattern of the input device 17. (Four).

Next, in the energization time calculation device 13,
Multiply HGmax by a constant C based on the margin rate to calculate the energization time.
Calculate Hs (5). On the other hand, in the boiling temperature setting device 14, the temperature sensor 9 measures the water supply temperature Ti in the hot water storage tank 1 (6), and the energization time Hs calculated by the energization time calculation device 13 and the water supply temperature Ti, The boiling temperature To is set from the hot water storage tank capacity Vt and the rated power consumption W of the heating element 5 (7). Next, after time switch 8 is turned on (8-Hs)
It is determined whether the time of
When the water temperature reaches To (10), the energization to the heating element 5 is turned off (11), the calculation of the energization time measuring device 16 is completed (12), and the actual energized HG is stored in the memory. 12 and update the data (13). In this case, if there is no hot water remaining in the hot water storage tank 1, the heating element 5
The energization off time matches the time switch 8 off time, but in reality they do not match because of residual hot water.

Furthermore, the late-night power supply time end time, for example, 7
When the time comes, time switch 8 turns off (14) and stops (15).

In addition, in the above embodiment, the energization time calculation device 13
In the calculation of the energization time Hs, the maximum HGmax among the data in the storage device 12 was used, but 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.

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. Since the time to energize the heating element is determined by the input device, the amount of hot water corresponding to the user's actual situation can be obtained every day, so the amount of remaining hot water is smaller than that of a device without an input device. The data in the storage device is updated every time. In other words, since it has a learning function, it can adequately respond to the daily changing amount of hot water used. In addition, since the start time of energization of the heating element is shifted later than the start time of late-night power supply, the boil-up time is closer to the end time of midnight power supply, and therefore, heat dissipation loss after boil-up occurs. This has the advantage of reducing maintenance costs.

[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 a switch, and 11 is a control unit , 12 is a storage device, 13 is an energization time calculation device, 14 is a boiling temperature setting device, 1
5 is an energization control device, 16 is an energization time measuring device, 1
7 is an input device. Note that the same reference numerals in the figures 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 the amount of water scheduled to be used the next day. an input device for selecting and inputting a pattern from among a plurality of patterns;
A storage device that stores the input from the input device and the actual energization time as data, and a required energization to the heating element based on the actual data in the storage device that corresponds to the pattern input from the input device. an energization time calculation device that calculates the time; a boiling temperature setting device that sets the boiling temperature from the water supply temperature, the required energization time, the hot water storage tank capacity, and the rated power consumption of the heating element; and the energization time calculation device. In order to obtain the required energization time during the midnight power supply time, the power supply to the heating element is started later than the midnight power supply start time, and the temperature detected by the temperature detection means is set at the boiling temperature setting device. an energization control device that stops energizing the heating element when a set boiling temperature is reached;
1. A control device for a hot water storage type electric water heater, comprising: an energization time measuring device that measures the energization time to the heating element and inputs the value into the storage device to update the data.