JPS61153341A - Control device of electric water heater - Google Patents

Abstract

PURPOSE:To contrive to reduce the heat loss and improve the detection accuracy of the quantity of residual hot water by a constitution wherein the necessary heat quantity and the quantity of hot water are calculated based upon the quantity of feed water and the quantity and temperature of residual hot water and the prepared hot water is stored in a tank from above in a hot water storage type electric water heater. CONSTITUTION:The quantity of used hot water detected with a flow sensor 8 and hot water temperatures measured with a lower temperature sensor 15 and an upper temperature sensor 16 are respectively inputted to a calculating means 20. The required heat quantity is calculated based upon the temperature measured with the lower temperature sensor 15 at the required heat quantity calculating part 21 of the calculating means 20. On the other hand, the quantity of residual hot water is calculated based upon the flow rate detected with the flow sensor 8 and the signal emitted from a valve controlling means 18 at the residual hot water quantity measuring part 22. The heat quantity of residual hot water is calculated based upon said calculated quantity of residual hot water together with the temperatures measured with the upper and the lower temperature sensors 15 and 16 at the residual hot water quantity calculating part 23 and, after that, sent to the heating-up hot water quantity calculating part 24, which outputs the control signal to a pump controlling means 27 based upon the quantity circulated calculated from the required heat quantity obtained at the part 21 and the quantity of residual hot water obtained at the part 23. Further, the energizing time is determined at the required energizing time calculating part 26 in order to control the energizing control means 28.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a hot water storage type electric water heater, in which a pump and a heating device are provided in the middle of a circulation path that communicates the upper and lower parts of the hot water storage tank. This invention relates to a control device for an electric water heater that stores hot water at a constant temperature.

[Conventional technology]

A schematic structural diagram of a conventional hot water storage type electric water heater is shown in Figure 4 and Figure 5.
This will be explained using the main electrical circuit diagram shown in the figure.

In FIG. 4, 1 is a hot water storage tank, and a heating element 2 is attached to the lower part of the tank.

3. An automatic degree regulator for controlling the boiling temperature, which is attached to the lower wall of the hot water storage tank. 4
5 is a water supply pipe for taking out hot water boiled in the hot water storage tank 1, and 5 is a water supply pipe for supplying water from a water source to the hot water storage tank 1.

In FIG. 5, 6 is a power source, and 7 is a time switch for setting the midnight power supply time.

Next, the operation will be explained. When the power is turned on at midnight,
When the time switch 7 is turned ON, power to the heating element 2 is started. The capacity of the heating element 2 is set so that the water can be boiled from approximately 8°C to a target temperature of 85°C within 8 hours of late-night power supply.

When the water in the hot water storage tank 1 is boiled to 85°C, the automatic temperature regulator 3 opens the contact and stops powering the heating element 2, and then the automatic temperature regulator 3 repeatedly opens and closes the contact. The hot water storage tank 1 is filled with hot water at 85°C every morning.

[Problems to be solved by the invention] However, the amount of hot water used is not always the same, and the amount varies depending on the season. In particular, whether a person takes a bath or not 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.

Therefore, the boiling time is different depending on whether there is residual hot water or not, and when there is residual hot water, the water will boil up in a short time. Because of this, high school 8th grade students were excited! This has the problem that the hot water is left unused for a long time, resulting in a large loss of heat due to natural heat radiation from the hot water storage tank.

This invention attempts to solve these conventional problems, and aims to reduce the amount of remaining hot water to reduce heat loss, and to improve the accuracy of detecting the amount of remaining hot water.

[Means for Solving Problem 1] The electric water heater control device according to the present invention includes a central temperature sensor that detects the temperature of hot water in the center of the hot water storage tank, a flow rate sensor that detects the amount of hot water used, and the A valve control means for controlling switching of the switching valve based on the detected value of the central temperature sensor, a remaining hot water amount measuring means for measuring the remaining amount of hot water from the detected value of the flow rate sensor after the switching valve is activated, and a remaining hot water amount measuring means for controlling the temperature of water supplied to the hot water storage tank. A lower temperature sensor detects, an upper temperature sensor detects the in of the upper part of the hot water storage tank, and appropriate circulation for storing hot water at a predetermined temperature based on the detected values of the lower temperature sensor and the upper temperature sensor and the measured value of the remaining hot water amount measuring means. a calculation means for calculating the amount of electricity and the required energization time required for boiling; a pump control means for controlling the circulation amount of the pump based on the calculation result; It has been established.

[Effect]

In this invention, each detected value of the lower temperature sensor, upper temperature sensor, and flow rate sensor is inputted as data to the calculation means, the calculation means performs a preprogrammed calculation process, and the pump control means performs appropriate calculation according to the calculation result. The pump is controlled so that the circulation amount is obtained, and the energization control means controls stopping of the heating device and the pump.

〔Example〕

An embodiment of the present invention will be described below based on the overall configuration diagram in FIG. 1 and the control block diagram in FIG. 2.

In FIG. 1, reference numeral 1 denotes a hot water storage tank, and water is supplied through a flow rate sensor 8 provided in the middle of a water supply pipe 5.

S is a first hot water sampling pipe 10 communicating with the upper part of the hot water storage tank 1;
11 is a switch such as a three-way electric valve to which the first hot water sampling pipe tE3 and the second hot water sampling pipe 10 are respectively connected. With the valve 11, hot water is supplied from either the first hot water sampling pipe S or the second hot water sampling pipe 10 when the faucet is opened.

12 is a circulation path that communicates the upper and lower parts of the hot water storage tank 1;
A heating device 14 containing a pump 13 and a heating element 2 is provided in the middle of this circulation path.

A lower temperature sensor 15 is provided at the lower part of the hot water storage tank 1, and an upper temperature sensor 16 is provided at the upper part to measure the water temperature within the hot water storage tank 1. Further, 17 is a central temperature sensor for measuring the temperature of hot water coming out from the second hot water sampling pipe 10, and is attached to the m wall of the hot water storage tank 1 at a slightly lower part of the joint of the second hot water sampling pipe 10.

On the 1st, depending on the detected value of the central temperature sensor 17, hot water is drawn from the first hot water sampling pipe S or from the second hot water sampling pipe 1.
It is a valve sub-section means that selects whether to draw hot water from 0 and controls the switching valve 11.

The detected values from each of the sensors 8, 15, and 16 are input to the calculation means 20 as data.

The calculation means 20 is composed of a microconbeater, and as shown in FIG.
2. Remaining tIjI heat amount calculation unit 23, boiling water amount calculation unit 2
4. It is composed of a circulation amount calculation section 25 and a required energization time calculation section 26.

Now, the boiling rating of this equipment is to supply hot water of 11℃ Vi (j), the detection value of the lower temperature sensor 15 is 1w℃, the detection value of the upper temperature sensor IB is 12℃, and the remaining hot water amount will be described later. The amount of remaining hot water measured by the measurement unit 22 is Vu
(j) and its operation will be explained.

When time switch 7 is ONL and power supply B is supplied,
Rating rating and detection value Tw℃ of lower temperature sensor 15
From this, the required amount of heat K i (Keal) that must be stored in the hot water storage tank 1 is calculated.

The calculation is based on the formula below.

K i =V i X (T i Tw) (
On the other hand, the remaining hot water calorific value calculation unit 21 calculates the value Tw°C detected by the lower temperature sensor 15, the detected value Tz ”Q of the upper temperature sensor IB, and the remaining hot water 1ikVu (J) measured by the remaining hot water amount measuring unit 22, which will be described later. The amount of unused hot water (hot water in 5) in the hot water storage tank 1 is determined as the amount of heat, and the residual water heat jt K z (Keal) is calculated using the following formula.

Kz-(Vt-Vu) X (Tz-Tw)
(Kcal) Here, Vt(j) is the tank capacity of the hot water storage tank 1.

Next, the boiling water amount calculation unit 24 calculates the required heat amount Ki (Kea
In order to satisfy l), the amount of heat excluding the 8m calorific value K z (Meal) is heated to a constant temperature of To℃ (e.g. 85℃).
It calculates If when storing as To℃ on the day.
The amount of tIk Vo (j) to be heated and stored is calculated using the following formula.

vo= (ni-Kz) / (To-Tw)
(1) The circulation amount calculation unit 25 calculates the heating value of the water at T w °C sucked from the bottom of the hot water storage tank 1 by the pump 13! 1
T
The purpose is to find the appropriate flow rate of the pump 13 necessary to store hot water at O℃ in the upper part of the hot water storage tank 1, and the circulation amount Qo
(j/Hr) is calculated using the following formula.

Qo = (WX 880X 7) / (To
-Tw) (1/Ear) Here, wa is heating efficiency to compensate for loss during heating circulation.

Next, the energization required time calculation unit 26 converts the hot water of To°C to Vo (
j) to calculate the heating value W114 and the time the pump 13 should be operated, and the required energization time Ho
(time) is determined by Ho = Vo / Qo (time).

The pump control means 27 controls the flow rate wJ of the pump 13 based on the calculation result of the circulation amount calculation section 2S.

The energization sub-section means 28 controls the energization stop of the heating element 2 and the pump 13 based on the calculation result of the energization required time calculation section 2B, and starts energization when the time switch 7 is turned on, and the Ho time is reached. When the energization time is secured, the energization is stopped.

Next, the method for measuring the amount of remaining hot water will be explained.

The valve control means 18 controls the switching valve 11 to take out hot water from the second hot water sampling tlo when the detected value of the central temperature sensor 17 is above a predetermined temperature (for example, 45°C), and when the detected value of the central temperature sensor 17 is above a predetermined temperature (in the above example, (when the temperature is lower than 45°C), the switching valve 11 is turned to draw hot water from the first hot water sampling pipe 9.

On the other hand, data on the amount of used hot water detected by the flow rate sensor is input to the remaining hot water amount measuring section 22.

However, here, since the entire amount of hot water used is measured, the flow rate is measured from the time when the switching valve 11 is not switched from the second hot water sampling pipe 10 to the first hot water sampling pipe S.

The amount of hot water above the communication part of the second hot water sampling pipe 10 to the hot water storage tank 1 is a fixed value, and is measured by the flow rate sensor after switching between the hot water amount at the top of B and the first hot water sampling pipe date. It can be calculated as the difference in the amount of hot water used.

Note that the flow rate sensor used here can be a known pulse-emitting type.

Next, we will take some time to explain the operating steps in FIG.

First, there is a control program stored in a microcomputer. Durham starts, time switch 7 turns on, power supply 6
is supplied (step 101), an internal timer (not shown) is started (step 102).

Next, each temperature sensor Is, 1B detects the water supply temperature Tw'Q,
By detecting the upper temperature Tz'Q and measuring the remaining hot water amount s22, i! lE#ih Detecting the quantity Vu (7) (x?yP10
3).

Based on these detected values, the calculation means 20 calculates the circulation amount QOC1.
/hour), calculate the required energization time Ha (step 10
4).

Next, the pump dividing means 27 controls the circulation rate of the pump 13 to be QO (j/hour II) (step 105), and the heating device i! i! 14 heating element 2 and pump 13 are started (step 106).

Next, use the internal timer to monitor whether 80 hours have passed since the time switch 7 turned 0rlJ.Step 107
), the energization control means 28 stops the heating value M14 and the energization of the pump 13 (step 108).

Thereafter, after eight hours of midnight power supply time have elapsed, the time switch 7 is turned off (step 109), and the brightness control program ends.

〔Effect of the invention〕

As described above, the present invention detects the temperature of water supplied to the hot water storage tank, the amount of hot water remaining, and the temperature of the remaining hot water, calculates the required amount of heat, calculates the required amount of hot water from this amount of heat, and stores it from the top of the hot water storage tank. Because of this structure, hot water at a constant temperature can always be supplied, unnecessary hot water is not left unused for a long time, and maintenance costs can be reduced by using a hot water tank.

Further, since the amount of remaining hot water is detected based on the amount of hot water used for a predetermined amount of hot water in the hot water storage tank, the accuracy of detecting the amount of remaining hot water can be further improved.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is an overall configuration diagram, FIG. 2 is a control block diagram, and FIG. 3 is an operation flowchart. FIGS. 4 and 5 show a conventional hot water storage type electric 9C hot water shower. FIG. 4 is a schematic structural diagram thereof, and FIG. 5 is a main electrical circuit WI diagram. In the figure, 1 is a hot water storage tank, 2 is a heating element, 8 is a flow rate sensor, 1 is a first hot water sampling pipe, 10 is a second hot water sampling pipe, 11 is a switching valve, 12 is a circulation amount, 13 is a pump, 14 is a heating device, 1
5 is a lower temperature sensor, 1B is an upper temperature sensor, 1st valve m garden means, 20 is calculation means, 27 is pump control means, and 2nd is energization SG control means. Agent Masuo Oiwa (2 others) Sai1 Figure 1: Ekenbe Tashif Figure 2 Figure 3 Field

Claims (1)

[Claims] A pump and a heating device are provided in the middle of a circulation path that communicates the upper and lower parts of the hot water storage tank, and a first hot water sampling pipe that communicates with the top of the hot water storage tank and a first hot water pipe that communicates with a predetermined position that divides the amount of hot water in the hot water storage tank are provided. In an electric water heater in which the hot water sampling pipe No. 2 is connected to a faucet via a switching valve, the central temperature sensor detects the temperature of hot water in the center of the hot water storage tank, the flow rate sensor detects the amount of hot water used, and the central temperature sensor. a valve control means for controlling the switching of the switching valve based on the detected value of the switching valve; a remaining hot water amount measuring means for measuring the amount of remaining hot water from the detected value of the flow rate sensor after the switching valve is activated; A lower temperature sensor, an upper temperature sensor that detects the temperature at the upper part of the hot water storage tank, and an appropriate circulating amount to be stored at a predetermined hot water temperature based on the detected value of the lower temperature sensor, the detected value of the upper temperature sensor, and the measured value of the remaining hot water amount measuring means. a calculation means for calculating the required energization time for boiling; a pump control means for controlling the pump so as to obtain the circulation amount calculated by the calculation means; and energization control means for controlling the operation of the pump to be stopped.