JPS6125058B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot water storage type electric water heater that utilizes late-night electricity. The object of the present invention is to provide a device that starts energization in the middle of the late-night power energization time zone so that the required time can be obtained at the same time as the time ends.

Figure 1 shows the main power supply circuit of a conventional hot water storage type electric water heater that uses late-night electricity. In the figure, 1 is a power supply, 2 is a time switch for late-night power, and the power is generally turned on from 11:00 p.m. to 7:00 p.m. 3 is a heating element, which boils water at around 8℃, which corresponds to the water temperature in winter, to 85℃ during the late-night power-on period.
The heating element capacity is set. 4 is an automatic temperature regulator, which has a normally closed contact and opens when the amount of hot water in the hot water storage tank reaches 85°C.

Next, the function and operation will be explained. When the midnight power supply start time arrives, the contact of the time switch 2 is closed and the power supply to the heating element 3 is started. When the amount of hot water in the hot water storage tank reaches 85° C., the contact of the automatic temperature controller 4 is opened and the electricity to the heating element 3 is stopped. The time switch 2 is almost never energized for the entire energization time frame. 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.
It varies from day to day and largely from season to 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 greatly affects the amount of hot water that can be extracted, and in the summer when the water temperature is high, a larger amount of hot water can be extracted than in the winter. However, the amount of hot water used remains the same throughout the year, or rather, the actual amount used decreases in the summer because hot water is used at a lower temperature, and there is a large amount of hot water left over in the summer.

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 and heat radiation from hot water stagnant in the pipes. Ta.

The present invention aims to eliminate these drawbacks, and calculates the required energization time to the heating element based on the preset value of the next day's hot water consumption and the water supply temperature, and calculates the end time of late-night power energization. By starting energizing the heating element in the middle of the late-night power energization period so as to obtain the above-mentioned required energization time, it is intended to eliminate unnecessary boiling.

The present invention will be explained below based on the block diagram shown in FIG. In FIG. 2, reference numeral 5 denotes a hot water amount setting means for presetting the amount of hot water to be used on the next day stored in the hot water storage tank, 6 a water supply water temperature sensor for detecting the temperature of water supplied to the hot water storage tank, and 7 a hot water amount setting means 5. 8 is a calculator that calculates the required energization time to the heating element from the set value set in and the water supply temperature detected by the water supply water temperature sensor, and 8 is a calculator that calculates the required energization time to the heating element from the set value set in , and the water supply temperature detected by the water supply water temperature sensor. This is a timer device for starting energization of the heating element 9 from the middle of the energization time period. The heating element 9 has the same rating as the heating element 3 in FIG.

Next, to explain an example of its operation using symbols and formulas, let the input value of the amount of hot water used on the next day set by the hot water amount setting means 5 be V liters (water temperature T°C), and the input value of the water supply water temperature sensor 6 immediately after the start of energization. If the detected value is t°C, the calculator 7 performs the calculation (T-t)×V÷860÷W, and calculates the required energization time. (1KWH=860Kcal). Here, W represents the power consumption (KW) of the heating element 9. The timer device 8 starts energizing the heating element 9 so that the required energizing time determined by the calculator 7 can be obtained at the end time of the midnight power energization.

As described above, according to the present invention, the thermal calories to be stored in the hot water storage tank are automatically calculated based on the set value of the amount of hot water used by the user and the detected value of the water temperature supplied to the hot water storage tank. The required energization time for the heating element is calculated from this heat calorie, and the timer device is used to control the energization time so that it is obtained at the same time as the midnight energization end time.
Not only can the power transmission efficiency be improved by alleviating power load peaks, but it also eliminates the need to supply more power than necessary or boil more water than necessary, reducing the amount of remaining hot water each day and reducing heat loss. This has the effect of further reducing maintenance costs.

[Brief explanation of the drawing]

FIG. 1 is a main power supply circuit diagram of a conventional hot water storage type water heater, and FIG. 2 is an energization control block diagram according to the present invention. 5 is a hot water amount setting means, 6 is a water supply water temperature sensor, 7 is
8 is a computing unit, and 8 is a timer device.

Claims (1)

[Claims] 1. A hot water amount setting means for presetting the amount of hot water used to be stored in a hot water storage tank, a water supply temperature sensor for detecting the temperature of water supplied to the hot water storage tank, and a setting value set by the hot water amount setting means and detected by the water supply water temperature sensor. Calculating means for calculating the thermal calories to be stored in the hot water storage tank based on the supplied water temperature, and calculating the required energizing time to the heating element from this thermal calorie; A hot water storage type electric water heater, comprising: a timer device that controls the start time of energization to the heating element so as to reach the end time.