JPS6365864B2 - - 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 utilizes late-night electricity. By calculating the required energization time and starting energization to the heating element in the middle of the late-night power energization time so that the energization time can be obtained at the same time as the end of the late-night power energization time, the remaining amount of hot water and heat loss after boiling can be reduced. The aim is to reduce the

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 the figure, 1 is a hot water storage tank, 2 is a heating element, and 3
is an automatic temperature controller, 4 is a power supply, and 15 is a time switch for late-night power, which is generally turned on from 11:00 p.m. to 7:00 the next morning.

Next, the function and operation will be explained. When the midnight power supply start time arrives, the contact of the time switch 15 is closed, and the supply of electricity to the heating element 2 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 3 are opened and the electricity to the heating element 2 is stopped. In this way, the entire amount of stored hot water is boiled to 85℃ every morning.

However, the amount of hot water used is not always the same and varies from day to day and largely depending on the season.
In particular, whether or not a person takes a bath is a factor that greatly influences the amount of hot water used, and on days when a person does not take a bath, more than half of the stored hot water may remain. Additionally, depending on the season, the temperature of the water supply has a great effect on the amount of suitable hot water that can be extracted, and in the summer when the water supply temperature is high, a larger amount of suitable temperature water can be extracted than in the winter. On the other hand, the amount of hot water used is almost 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, so there is more hot water left over in the summer.

Therefore, if there is residual hot water, the hot water will boil quickly and the hot water will be left unused for a long time.

Leaving hot water at an unnecessarily high temperature unused for a long time like this 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. It was hot.

The present invention aims to solve these drawbacks by making it possible to set the amount of hot water used each day and the amount of hot water used only the next day in advance.・Calculate the required energization time to the heating element with reference to the detected value of the residual water temperature, and start the heating element from the middle of the energization period of the late-night electricity so that the required energization time can be completed by the time when the energization of the late-night electricity ends. By starting energizing the
This aims to reduce the amount of hot water and eliminate as much heat loss as possible after boiling.

The present invention will be explained below based on the energization control block diagram shown in FIG. In FIG. 3, 12 is a constant hot water amount setting device for presetting the daily amount of hot water stored in the hot water storage tank 1, and 14 is a provisional hot water amount setting device for similarly setting the amount of hot water to be used only for the next day. For example, if you do not take a bath the next day or do not use hot water, the temporary hot water amount setting device 1 is set.
The amount of hot water used is set by the operation 4, and the value set by the constant hot water amount setting device 12 is automatically restored two days later.

Reference numeral 5 denotes a water supply temperature sensor for detecting the temperature of water supplied to the hot water storage tank 1, and 6 indicates a sensor based on a set value set by the steady hot water amount setting device 12 or provisional hot water amount setting device 14 and a detection value detected by the water supply temperature sensor 5. This is a calculator A that calculates the thermal calories of hot water to be stored in the hot water storage tank 1.

Reference numeral 7 indicates a remaining hot water amount sensor for detecting the amount of remaining hot water in the hot water storage tank 1, 8 indicates a remaining hot water temperature sensor for detecting the remaining hot water temperature in the hot water storage tank 1, and 9 indicates each of the above-mentioned sensors 5, 7, and 8. This is an arithmetic unit B for calculating the remaining hot water heat calories from each detection value detected by the .

10 is a calculator C for calculating the required energization time to the heating element 2 from the difference in thermal calories obtained by the calculator A6 and the calculator B9; This is a timer device for starting energization of the heating element 2 in the middle of the late-night power energization time period so as to obtain the determined energization time.

Next, a concrete example of the operation of the above configuration will be explained using symbols and formulas. First, the amount of hot water inputted by the steady water amount setting device 12 or the temporary hot water amount setting device 14 is set as V liters (water temperature T ₁ degree),
The detected value of the water supply temperature sensor 5 immediately after entering the late-night power-on period is t degrees, the detected value of the remaining hot water amount sensor 7 is v liters, and the detected value of the remaining hot water temperature sensor 8 is
Assuming that T is ₂ degrees, the calculation unit A6 calculates K ₁ = (T ₁ - t)V, and calculates the end time of the late-night electricity supply time or the thermal calorie K ₁ (Kcal) of the amount of hot water that should be stored in the hot water storage tank 1. ) is calculated.

Further, the calculator B9 calculates K ₂ =(T ₂ −t)v to calculate the thermal calorie K ₂ (Kcal) of the amount of hot water remaining in the hot water storage tank 1 as residual hot water.

Based on K ₁ and K ₂ calculated by the arithmetic unit A6 and the arithmetic unit B9, the arithmetic unit C10 calculates H= _K1 - _K2 /860×W, and stores the hot water in the hot water storage tank 1. The required energization time H (hr) to the heating element 2 is calculated from the net heat calorie that should be applied by subtracting the heat calorie K ₂ held by the remaining hot water from the heat calorie K ₁ of the amount of hot water that should be kept.
(1KWH=860Kcal). Here, W represents the rated power consumption (KW) of the heating element 2. Then, the timer device 11 starts energizing the heating element 2 from the middle of the energization time period of the late-night power so that the required energization time determined by the arithmetic unit C10 is obtained at the end time of the energization of the late-night power, and the heating element 2 Power supply is controlled so that boiling ends at the same time as the end of the late-night power supply time. Therefore, the greater the amount of hot water remaining in the hot water storage tank 1 and the higher the temperature of the remaining hot water, the less time the heating element 2 requires to be energized, and there is no need to leave hot water in the hot water storage tank 1 for a long time. Therefore, heat radiation loss can be reduced. Furthermore, since the hot water amount setting can be set appropriately between daily and next day only, maintenance costs are also reduced.

As described above, the present invention includes a constant hot water amount setting means for presetting the amount of hot water used each day, a provisional hot water amount setting means for setting the amount of hot water used only for the next day, and detecting the temperature of water supplied to the hot water storage tank. a calculation means A for calculating the thermal calories of hot water to be stored in the hot water storage tank from the set value set by the hot water amount setting means and the detected value detected by the water supply temperature detection means; a remaining hot water amount detection means for detecting the amount of remaining hot water in the hot water storage tank; a remaining hot water temperature detection means for detecting the temperature of the remaining hot water in the hot water storage tank; and a calculation means B for calculating the remaining hot water thermal calories from each detection value detected by each of the detection means. , a calculation means C that calculates the required energization time to the heating element from the difference between the thermal calories calculated by the calculation means A and the calculation means B, and the required energization time calculated by the calculation means C at the end time of the late-night power supply. The device is equipped with a timer device to start energizing the heating element from the middle of the late-night power supply period to obtain the required heat. Calories are calculated, and the required time to energize the heating element is calculated, and energization is carried out during the latter half of the late-night energization period, and the amount of hot water used can be selected as appropriate, whether daily or only for the next day. Since it is configured so that it can be set according to
This has the effect of reducing heat radiation loss after boiling and lowering maintenance costs.

In addition, since the device according to the present invention is energized during the latter half of the late-night power supply time period, if it is used in combination with conventional late-night power usage equipment whose load is concentrated in the first half, the power load during the first half of the power supply time period will be reduced. It also has the effect of easing the peak and improving power transmission efficiency.

[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, and FIG. 3 is a block diagram of energization control according to the present invention. 1 is a hot water storage tank, 2 is a heating element, 5 is a water supply temperature sensor, 6 is a calculator A, 7 is a remaining hot water amount sensor, 8
9 is a remaining hot water temperature sensor, 9 is an arithmetic unit B, 10 is an arithmetic unit C, 11 is a timer device, 12 is a constant hot water amount setting device, and 14 is a provisional hot water amount setting device.

Claims (1)

[Claims] 1. A steady hot water amount setting means for presetting the daily amount of hot water used, a provisional hot water amount setting means for similarly setting the amount of hot water used for the next day, a water supply temperature detection means for detecting the temperature of water supplied to the hot water storage tank, and the above-mentioned Calculating means A for calculating the thermal calories of the amount of hot water to be stored in the hot water storage tank from the set value set by the steady hot water amount setting means or the temporary hot water amount setting means and the water supply temperature detected by the water supply temperature detection means; A remaining hot water amount detection means for detecting the amount of remaining hot water, a remaining hot water temperature detection means for detecting the temperature of the remaining hot water in the hot water storage tank, and a calculation means for calculating the remaining hot water thermal calories from each detection value detected by each of the detection means. B, a calculation means C that calculates the required energization time to the heating element from the difference in thermal calories calculated by the calculation means A and the calculation means B;
A hot water storage type electric water heater comprising a timer device for starting energization of the heating element from the middle of the late-night power supply period so as to obtain the required power supply time determined by the calculation means C at the end time of the late-night power supply. Control device.