JPS6030934A - Control device for hot water storage type electrical water heater - Google Patents

Abstract

PURPOSE:To enable a use of capacity of the titled water heater in response to the actual requirement at the user side by a method wherein a required energization time to be applied to a heater is calculated in response to the actual use- record of use of volume of hot water at the user side and the starting of energization of the heater is shifted after the starting time of energization of the heater. CONSTITUTION:An energization time calculation device 13 calls the maximum value HGmax in the data stored in the memory device 12, for example, therefrom and multiplies by a constant C with a rate of mergin being added and calculates the energization time Hs (Hr) as Hs=HGmaxXC. The energization control device 15 controls the turning-ON or turning-OFF operation of the switch 10, turns ON the switch 10 after a time of (8-Hs) from the starting time of supplying an electrical power and turns OFF when the temperature sensor 9 detects the boiling point To.

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 designed to calculate the required energization time to be applied to a heating element based on the user's actual hot water usage record. In addition, the start of energization of the heating element is delayed after the start time of late-night power supply, so that the capacity of the conventionally fixed hot water storage type electric water heater can be used in accordance with the actual situation of the user. The purpose is to

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 water temperature 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 heated 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 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 capacity of the hot water storage tank is Vt (text), the boiling temperature in the hot water storage tank is To (°C), the temperature of the mixed hot water to be obtained is Tm (°C), and the temperature of the water to be mixed (water supply temperature). If Ti ('O) is, then the amount of mixed hot water V+n (text)
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 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 approximately constant throughout the year, but 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 rises 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 hot water usage record, for example, data on the amount of hot water used over the past 10 days, and this data is updated every day based on the amount of hot water used on that day.In other words, it has a learning function, and the required By calculating and controlling the required energization time to the heating element so that the amount of mixed hot water is always obtained, and by shifting the start time of energization later than the start time of late-night power supply, the remaining amount of hot water is reduced and It is designed to eliminate heat loss as much as possible.

Hereinafter, one embodiment of this invention @ Figure 3 shows the overall configuration, and Figure 4 shows the overall configuration.
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 the supply of electricity to the heating element 5, which is opened and closed by the operation of a control section, which will be described later. Reference numeral 11 denotes the above-mentioned control unit, a storage device 12, and a current-carrying time calculation device 13.
．． Boiling temperature setting device 14, energization control device 15. and an energization time measuring device 16.

The storage device 12 stores as data the actual HG of several days of energization time measured by the energization time measuring 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 energization time calculation device 13 calls the maximum value HGmax from the data stored therein (10 days in the above example) from the storage device 12, for example, and calculates a constant C based on the margin rate (for example, margin rate 10 days). %, it becomes 1.1) to calculate the energization time Hs (Hr) as Hs = HGmaxXC.

The boiling temperature setting device 14 calculates the energization time Hs calculated by the energization time calculation device 13 and the hot water storage tank capacity Wrt (text).
, the rated power consumption W (k'w) of the heating element 5, and the water supply temperature T
From i ('C), calculate the boiling temperature To (°C) using the following formula.

The energization control device 15 controls the on/off of the switch 10, and starts from the midnight power supply start time (8-Hs).
) After a period of time, the switch 1o is turned on, and the switch 1o is turned off when the temperature sensor 9 detects the rising temperature T0.

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, and measures the time from when the energization control device 15 turns on the switch 10 to when it is turned off. This is the power-on time.

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.

The time switch 8 is turned on at midnight, for example at 23:00 (2). First, the energization time measuring device 16 starts measuring operation 3), and the storage device 12
The largest value HGmax of the latest data is called from (4).

Next, the energizing time calculation device 13 calculates the energizing time Hs by multiplying HGmax by a constant C based on the margin rate (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 (8), the energization time Hs calculated by the energization time calculation device 13, the water supply temperature ITi, the hot water storage tank capacity vt1 heat generation The boiling temperature T0 is set from the rated power consumption W of the body 5 (7).

Next, it is determined whether the time (8-Hs) has elapsed since the time switch 8 was turned on (8), and when the time has elapsed, electricity is started to be applied to the heating element 5 (8), and the temperature sensor 9 detects the water temperature. When becomes To (1o), 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 energization result HG is stored in the storage device 12.
and update the data (13). In this case, if there is no hot water remaining in the hot water storage tank 1, the time when the power to the heating element 5 is turned off coincides with the time when the time switch 8 is turned off, but in reality they do not match because of the remaining hot water.

Further, at the end of the late night power supply time, for example 7 o'clock, the time switch 8 is turned off (14) and stopped (15).

In the above embodiment, the energization time calculation device 13 calculates the energization time Hs using the maximum H of the data in the storage device 12.
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, in this invention, the latest data on the energization time is stored in the storage device as past results, and the time to energize the heating element is determined based on this data. Since the amount of hot water that is available every day is based on the actual situation, the amount of remaining hot water is reduced.Also, since the start time of electricity supply to the heating element is shifted to later than the start time of late-night power supply, the boiling time is shorter than the late-night power supply time. This has the advantage of reducing heat radiation loss after boiling up and lowering maintenance costs.

[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 a switch, 11 is a control unit, 12
13 is a storage device, 13 is an energization time calculation device, 14 is a boiling temperature setting device, 15 is an energization control device, and 16 is an energization time measuring device. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (2 others) Figure 1 Figure 3

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 data on the actual time of energization. an energization time calculation device that calculates the required energization time for the heating element based on the data; and a energization time calculation device that calculates the required energization time for the heating element based on the data; Start energizing the heating element later than the midnight power supply start time so that the required energization time determined by the boiling temperature setting device that sets the rising water temperature and the energization time calculation device can be obtained during the midnight power supply time. and an energization control device that stops energizing the heating element when the temperature detected by the temperature detection means reaches the boiling temperature set by the boiling temperature setting device, and a time period for energizing the heating element. 1. A control device for a hot water storage type electric water heater, comprising: an energization time measuring device that measures and inputs the measured value into the storage device to update the data.