JPS58130942A - Control device for hot-water reserving type electric water heater - Google Patents

Abstract

PURPOSE:To reduce heat dissipating loss and improve power transmission efficiency by a method wherein the necessary conducting time of electric power supplied to a heating body is operated by detecting feed water temperature and the amount of heat of the hot-water remaining in a hot-water reserving tank and the necessary conducting time is contrived so as to be completed at a time when the conduction of midnight electric power is finished. CONSTITUTION:The temperature of water fed into the hot-water reserving tank is detected by a feed water temperature sensor 6 while the amount of heat to be reserved is operated in an operator 7 from the detected value of the sensor 6 and the capacity of the hot-water reserving tank. The amount of heat of the hot-water remaining in the hot-water reserving tank is detected by the detecting unit 8 for the amount of heat of the remaining hot-water while the necessary conducting time is operated in the operator 9 from a difference between the amounts of heat detected by the operator 7 and the unit 8. The conduction of electric power supplied to the heating body 2 is controlled in a timer unit 10 so that the necessary conducting time, obtained by the operator 9, has been completed at the time when the supply of the midnight electric power is finished. The high-temperature hot-water, raised in the temperature thereof, will not be left for a long period of time and the heat dissipating loss may be reduced. Further, the electric power is supplied in the later half of the time band for supplying the midnight electric power, therefore, the power transmission efficiency may be improved.

Description

[Detailed Description of the Invention] The present invention relates to a hot water storage type electric water heater that uses late-night electricity.
Energy saving with less heat loss after boiling by calculating the energization time by understanding the water supply water temperature and residual water heat value, and controlling the energization so that the energization time ends at the same time as the end of the late-night electricity energization time. The aim is to provide equipment for

Figure 1 is a cross-sectional view of a general hot water storage type electric water heater, and Figure 2 is a main power supply circuit diagram of a conventional hot water storage type electric water heater that uses late-night electricity. 3 is a heating element, 3 is a thermostat, 4 is a power supply, 5 is a time switch for late-night power, and the power-on period is generally 8 hours from 11:00 p.m. to 7:00 the next morning.0 Heating element 2 is a power-on for late-night power. Approximately 8 degrees of water with a temperature of around 8 degrees Celsius, which corresponds to the water temperature in winter, is
The capacity of the heating element is preset to raise the temperature to 5°C. The thermostat 3 has a normally closed contact, and opens the contact when the temperature of the hot water in the hot water storage tank 1 reaches approximately 85°C.

Next, the function and operation will be explained. Late-night electricity start time t
When this happens, the contacts of the time switch 5 close, and the heating element 2
energization starts. The water temperature in hot water storage tank 1 is approximately 85.
When the temperature reaches ℃, the contacts of the thermostat 3 open and the heating element 2
The power supply to is stopped.

In this way, the entire amount of stored hot water is boiled to about 85°C every morning.

However, the amount of hot water used and the water supply temperature are 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.
On days when you don't take a bath, you end up with more than half of the stored hot water. Additionally, depending on the season, the temperature of the water supply has a large effect on the amount of suitable hot water that can be drawn, and in the summer when the water supply water temperature is high, a large amount of hot water can be drawn from the suitable temperature gutter compared to the winter. However, the amount of hot water used is generally constant throughout the year; in fact, the actual amount used is generally lower in the summer because hot water is used at a lower temperature.
There is a lot of leftover hot water in the summer.

Therefore, if there is residual water, it will boil in a short time.
However, conventionally, when the late-night power supply time comes, power supply to the heating elements 2 is started all at once. For this reason,
Immediately after power is turned on, the power load is concentrated, making it impossible to equalize the power load, which is the original purpose of late-night power, and resulting in poor power transmission efficiency. This has the drawback that the time it takes to stand without being used increases, and heat loss due to natural heat radiation increases.

Furthermore, conventional hot water storage type electric water heaters are not equipped with a device for detecting the amount of heat of remaining hot water, and only some of them are capable of detecting the amount of remaining hot water. Detecting the amount of remaining hot water was also a step-by-step process in which multiple temperature sensors, such as thermostats and thermistors, were placed on the outer wall of the hot water storage tank to detect temperature changes at those locations. For this reason, the amount of remaining hot water has not been used as data for the next boiling.

The present invention aims to eliminate these drawbacks, and calculates the required energization time to the heating element by detecting the water supply temperature and the amount of heat remaining in the hot water storage tank, and also calculates the required energization time at the end of the late-night power supply. The aim is to control the period of energization in a timely manner.

The present invention will be explained below based on the block diagram shown in FIG. In FIG. 3, 61 is a water supply temperature sensor for detecting the temperature of the water supplied to the hot water storage tank 1, and 7 is a water supply temperature sensor that is stored based on the detected value detected by the water supply temperature sensor and the tank capacity of the hot water storage tank 1. This is a computing unit A that calculates . Reference numeral 8 denotes a residual water heat quantity detection device that detects the residual water heat quantity in the hot water storage tank 1, and 9 a computing unit B that calculates the required energization time from the difference between the respective heat quantities detected by the arithmetic unit A7 and the residual water heat quantity detection device 8. , 10 is a timer device that controls the period of time during which the heating element 2 is energized so that the required energization time calculated by the arithmetic unit B9 can be completed at the time when the late-night power supply ends.

Next, an example of its operation will be explained in detail using a symbolic formula.

The tank capacity of hot water storage tank 1 is V(1) (hot water temperature T'C)
, if the detected value of the water supply water temperature sensor 6 immediately after entering the power-on time period for late-night power is t ("C), first, the computing unit A7
Performance of K=(T-t)xV) EH? (Kcal) is calculated as the amount of heat that should be stored in the hot water storage tank 1 by the end of the late-night power supply time. Further, the residual hot water heat quantity detection device 8 detects the calorific value Kz (Kcal) remaining as the residual hot water, for example, by a method described later.

Next, arithmetic unit B9 calculates H= (K, -)÷860÷W
The required energization time H (hr) is calculated from the net amount of heat to be applied excluding the remaining heat amount (I
KWH-860Kcal), where W represents the power consumption (KW) of the heating element 2, and the timer device 10 obtains the required energization time H (hr) determined by the calculator B9 at the end time of the midnight power supply. Control is performed so that power supply to the heating element 2 is started in the middle of the late-night power supply period.

Next, the residual water heat quantity detected by the residual water heat quantity detection device 8 is calculated as 2 (Kcal).
) will be explained using FIGS. 4 to 6.

That is, FIG. 4 is a sectional view of a hot water storage type electric water heater equipped with an example of the residual water heat amount detection device according to the present invention, and FIGS. 5 and 6 show temperature distribution charts inside the hot water storage tank at the time of detection. It is something.

In Fig. 4, 1 is a hot water storage tank, 11 is a hot water storage tank 1
A temperature detector is provided at the bottom of the hot water storage tank 1 to measure the temperature of the hot water inside, 12 is a water supply pipe, 13 is a hot water pipe, and 14 is a faucet provided at the tip of this water supply pipe. 15 is a circulation pump, one end of which is connected to the lower part of the hot water storage tank 1, and the other end of which is connected to the hot water supply pipe 13.
It is provided in the middle of a communication pipe 16 connected to the middle of the hot water storage tank 1, and the water in the lower part of the hot water storage tank 1 is circulated to the upper part of the hot water storage tank 1 through the communication pipe 16 and a part of the hot water supply pipe 13.

A method of detecting the amount of heat of remaining hot water in the above configuration will be explained with reference to FIGS. 5 and 6.

As shown in FIG. 4, it is assumed that the hot water storage tank 1 is initially filled with hot water at T1°C.

FIG. 5 shows the temperature distribution inside the hot water storage tank 1 after opening the faucet 14 and using hot water V, [1] in this state. In other words, CI water flows into the lower part 1a of the hot water storage tank from the water supply pipe 12 by the amount of hot water v+[f] used,
The hot water of T1[”CI is V2[f] in the upper part 1b of the hot water storage tank.
Remaining. In this state, with the faucet 14 closed,
When the circulation pump 15 is operated, water in the lower part 1b of the hot water storage tank flows through the communication pipe 16 from the upper part 4b of the hot water storage tank and disturbs the hot water layer in the upper part 1b of the hot water storage tank, so that the temperature of the hot water gradually becomes average.

FIG. 6 shows the temperature distribution of the hot water storage tank 1 where the hot water temperature has been averaged in this way.

Therefore, the tank capacity of hot water storage tank 1 is V[il (eigenvalue V
= V r + V x ), the temperature measured by the temperature detector 11 installed at the lower part 1b of the hot water storage tank before the operation of the circulation pump 15 is t["C], and the temperature measured after the operation of the circulation pump 15 is T2[" Since it is CI, the heat value of the remaining water is 2 [K
cal ] can be calculated as follows.

K2 = vx (T2 t ) [kcal] As described above, in the present invention, the amount of heat to be heated is calculated by detecting the water supply temperature and the amount of heat of the remaining hot water, and from this amount of heat, the required energization time to the heating element is calculated. The system calculates the required energization time and controls the energization time period so that the fire is extinguished in line with the end of the late-night power energization period. This has the effect of reducing heat loss due to natural heat radiation and reducing maintenance costs.Also, since the system according to the present invention is energized in the latter half of the late-night power supply period, the load is reduced in the first half. When used in conjunction with devices that use electric power, which is traditionally the case late at night when electricity is concentrated, it will alleviate the peak power load during the first half of the power-on time period, and it will also have the effect of improving power transmission efficiency.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a general hot water storage type electric water heater, Fig. 2 is a main power supply circuit diagram of a conventional hot water storage type electric water heater, Fig. 3 is an energization control program diagram according to the present invention, and Fig. 4 5 is a cross-sectional view of a hot water storage type electric water heater equipped with an example of the residual water heat amount detection device according to the present invention, and FIGS. 5 and 6 are temperature distribution charts in the hot water storage tank when detecting the residual water heat amount. 1 is a hot water storage tank, 2 is a heating element, 6 is a water supply water temperature sensor,
7 is a computing unit A, 8 is a residual water heat detection device, 9 is a computing unit B,
10 is a timer device. Agent Shin Kuzuno - 21 Figure 4 13 51st;,! 2′6 [i

Claims (1)

[Claims] A water supply temperature sensor that detects the temperature of the water supplied to the hot water storage tank, a calculator A that calculates the amount of heat to be stored from the detected value detected by the water supply water temperature sensor and the tank capacity of the hot water storage tank, and a calculator A that calculates the amount of heat that should be stored from the detected value detected by the water supply water temperature sensor and the tank capacity of the hot water storage tank, and the remaining hot water in the hot water storage tank. a residual water heat quantity detection device that detects the heat quantity; a computing unit B that calculates the required energization time from the difference between the heat quantities detected by the computing unit A and the residual water heat quantity detection device; A control device for a hot water storage type electric water heater, comprising a timer device that controls energization to a heating element so as to obtain the required energization time determined by .