JPS6111547A - Hot-water reserving type electric water heater - Google Patents

Abstract

PURPOSE:To permit to set a feed water temperature closed to an actual feed water temperature by a method wherein an operating means, determining the feed water temperature of the day based on the lowest value, and a memory, memorizing water temperatures of a plurality of days and renewing the value of the oldest water temperature into the value of the latest day to memorize it, are provided in the heater. CONSTITUTION:The operating means 9 measures water temperature during 24hr from the beginning of midnight electric power conduction time band to the beginning of next midnight electric power conduction time band with a predetermined time interval. The operating means 9 measures the water temperature by a temperature sensor 1 with the predetermined time interval, takes a water temperature information converted into a digital value by an A/D converter 8 thereinto and decides whether the value is the lowest value in the newest day while the value of water temperature in the newest day, being memorized in the memory accommodated in the operating means 9, is renewed to the lowest value to memorize it when the digital value is the lowest value in the newest day. In case there is even one day, in which a hot-water remaining amount is small, among past 7 days when the days, in which hot-water is not used at all, are continued, the feed water temperature of the day may be determined correctly substantially and the hot-water may be heated up to the optimum heat-up temperature.

Description

[Detailed Description of the Invention] (Field of Application of the Invention) The present invention relates to an improvement in a hot water storage type electric water heater that boils and stores hot water using electric power during a specific time period such as a late-night power-on time period. be.

(Background of the Invention) Conventionally, a hot water storage type electric water heater that changes the boiling temperature of hot water according to changes in the water supply temperature is known from Japanese Patent Publication No. 58-6855. This has the advantage that the amount of hot water obtained by mixing tap water with the hot water in the water heater can be kept constant throughout the year.

In Japanese Patent Publication No. 58-6855, a temperature sensor for detecting the temperature of water supply is attached to a water pipe. However, since the water pipes and the electric water heater have different functions when getting off the train, it is not preferable to attach the temperature sensor to the water pipes. Therefore, as shown in FIG. 6, the temperature sensor 1 is usually adhered to the outer wall surface of the tank 2 near the water supply port 3.

At times other than the late-night power supply time period when the heater 4 is not energized, a mixed layer 7 is formed between the hot water 5 and the water 6, and the hot water 5
and water 6 do not mix. Therefore, if the temperature of the water 6 is measured by the temperature sensor l before the late-night power supply period,
You can get the water supply temperature.

However, when the amount of hot water 5 used is very small, only a small amount of water is supplied to tank 2, so the high temperature hot water 5 is
Due to the heat radiation and transfer from the tank 2, the temperature of the water 6 in the tank 2 becomes higher than when it is supplied from the water supply port 3. This makes it impossible to accurately detect the water supply temperature. Therefore,
In cases where the amount of remaining hot water is very large, the boiling temperature will be below the required level, resulting in a shortage of 71 fl-.

(Objective of the Invention) The object of the present invention is to provide a hot water storage type electric water heater that solves the above-mentioned problems and can determine a water supply temperature close to the actual water supply temperature even when there is a large amount of remaining hot water. It is.

(Features of the Invention) In order to achieve the above object, the present invention measures the water temperature by the temperature sensor at predetermined time intervals at least from the end of a specific time period until the start of a specific time period, and calculates the lowest value of the water temperature. a calculating means for determining the current supply water temperature based on the lowest value of the water temperature values for a plurality of days including the latest water temperature value; A memory is provided to update and store the old water temperature value to the latest water temperature value, and it is assumed that the measured water temperature immediately after water is newly supplied to the tank will be the lowest water temperature value when the remaining amount of hot water is at a minimum. The present invention is characterized in that the water supply temperature for the day is determined based on the temperature.

(Embodiment of the invention) FIG. 1 shows an embodiment of the invention. A temperature sensor 1 using a thermistor or the like is attached to the outer wall surface of the tank 2 near the water supply port 3, as shown in FIG. Information from the temperature sensor 1 is converted into a digital value by an A/D converter 8 and sent to a calculation means 9 such as a microprocessor. For example, as shown in FIG. 2, the time zone detection means 10 is composed of a photocoupler, and when the late-night power supply time period is entered, the heater power is turned on when a late-night power time switch (not shown) is turned on. When late-night power is applied to the terminal 11, a voltage is applied through the current leakage circuit breaker 12, the operation is started, and the late-night power application information is sent to the calculation means 9. The first memory 13 stores various operation commands of the calculation means 9, water temperature values for a plurality of days including the latest one, for example, the past seven days. The second memory 14 stores hot water temperature control patterns A and B shown in FIG. The setting operation means 15 is
It is used to select one of two μ temperature control patterns A and H, and is composed of, for example, a changeover switch. The output means 16 is for driving a relay 17 that controls energization of the heater 4, as shown in FIG. Display means 1
7 displays which of the hot water temperature control patterns A and H is set by flJI control of the display control means 18.

Next, the operation will be explained. The calculation means 9 measures the water temperature using the temperature sensor 1 at predetermined time intervals, for example, every minute, for 24 hours (latest 1) from the beginning of the late-night power supply period to the beginning of the next late-night power supply period. . The flowchart 1 is shown in FIG.

The calculation means 9 calculates 71 by using the temperature sensor 1 at predetermined time intervals.
il+ is set, and the A/D converter 8 converts it digitally (1r
The tree 11 converted to i, takes in the A information, and its latest 1
1, and if it is the lowest (fi), the latest water temperature value stored in the memory built in the calculating means 9 is updated to that value and stored. When the time slot starts, the calculation means 9 transfers the latest water temperature value stored in the built-in memory to the first memory 13 and stores it therein.

Next, the calculation means 9 performs calculation processing to determine the water supply temperature for that day, as shown in FIG. First, the oldest water temperature value is erased from the first memory 13. Then, water temperature values for consecutive days (seven days) including the latest intake are read from the first memory 13, and the lowest value among them is determined as the current day's water temperature.

The calculation means 9 reads the boiling temperature corresponding to the water supply temperature from the hot water temperature control pattern stored in the second memory 14, sends a signal to the output means 16 based on it, and controls the energization of the heater 4.

As a result, the water 5 is boiled to the read boiling temperature. At this time, the temperature inside the tank 2 becomes uniform due to the circulation of the hot water 5, so the temperature of the hot water 5 is detected by the temperature sensor l.

According to this example, even if there are consecutive days without using hot water,
If there are even 1 days in the past 7 days when the amount of hot water remaining is low, you can almost accurately determine the water supply temperature for that day, so you can boil the water to the optimal boiling temperature. There is no shortage of hot water supply. Also, at predetermined time intervals, for example, change the water temperature to 4σ for 1 minute? Since the 1111 constant is carried out, the water temperature can be immediately measured even when water is newly supplied to the tank 2 at any time of the day, and the lowest value can be memorized without fail. Furthermore, since the oldest water temperature value is deleted from memory, it is possible to always determine the water supply temperature closest to the water temperature of the season.

(Modified Example) In the illustrated embodiment, the lowest value of the water temperature values for multiple days including the latest water temperature is set as the water supply temperature on that day. corrected value,
For example, the candy added by 5% may be determined to have a water supply temperature of 1 bar on that day. In addition, the water temperature at the latest outlet was measured for 24 hours from the beginning of the late-night power period to the beginning of the next late-night power period; It is enough to reach the beginning of the band. Further, although the temperature sensor 1 is used both to detect the temperature of the water 6 and to detect the temperature of hot water when the heater is energized, it is also possible to use it exclusively for detecting the water temperature and to provide a separate temperature sensor for detecting the hot water temperature.

(Effects of the Invention) As described above, according to the present invention, the temperature sensor measures the water temperature at predetermined time intervals from the end of a specific time period to the start of a specific time period, and measures the lowest of the water temperatures. a calculation means that determines the water temperature of the day based on the lowest value of the water temperature values of the plurality of days including the latest water temperature value as the water temperature value of the latest water temperature; A memory is provided to update and store the old water temperature value to the latest water temperature value, so that the measured water temperature immediately after water is newly supplied to the tank with the remaining amount of hot water at the minimum becomes the lowest water temperature value. Since the water supply temperature for the day is determined based on assumptions, it is possible to determine a water supply temperature close to the actual water supply temperature even when there is a large amount of remaining hot water.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a circuit diagram showing its heater circuit, Figure 3 is a diagram showing its control pattern, and Figure 4 is a calculation process for the water temperature value at the latest outlet. FIG. 5 is a flowchart showing the operation, and FIG. 5 is a flowchart showing the calculation processing operation for the day's water supply temperature. FIG. 6 is a sectional view schematically showing the tank of a conventional electric water heater. l... Temperature sensor, 2... Tank, 3
...Water inlet, 4...Heater, 5...
...Hot water, 6...Water, 9...Calculating means, lO...Time zone detection means, 13...
First memory, 14... Second memory, 16...
...Output means. Patent Applicant: Tokyo Electric Power Company, Inc., 3 Representatives: Minoru Nakamura

Claims (1)

[Claims] 1. In a hot water storage type electric water heater equipped with a temperature sensor that is attached to a tank and detects the water temperature near the water supply port of the tank, the water temperature is measured by the temperature sensor at predetermined time intervals from the end of a specific time period until the beginning of a specific time period. measure,
a calculation means that determines the water supply temperature of the current day based on the lowest value of the water temperature values of a plurality of days including the latest day, with the lowest value of the water temperatures as a water temperature value of the latest day; and the water temperature of the plurality of days. A hot water storage type electric water heater, characterized in that it is provided with a memory that stores the water temperature value and updates and stores the oldest water temperature value to the water temperature value of the latest day.