JPH0674564A - Electric water heater - Google Patents

Abstract

PURPOSE:To enhance hot water storage efficiency by increasing a circulation flow rate when a remaining hot water quantity in a hot water storage tank exceeds a specified quantity and increasing the temperature of a whole quantity of hot water in the hot water storage tank and storing the hot water in the shape of a layer when it fails to exceed the specified quantity. CONSTITUTION:Hot water in a hot water storage tank 1 is circulated from the lower part of the tank to the upper part by way of a circulation line 11 and further by way of a heating tank 13 which has a heater 14 by driving a circulation pump 12. In the mean time, the quantity of hot water remaining in the storage tank 1 is detected with a remaining hot water quantity detection means 5. On the other hand, a specific time zone including a midnight time zone is detected with a time zone detection means 26. When the remaining quantity of hot water exceeds a specific quantity in this specific time zone, a controller 21 raises the temperature of the whole hot water quantity in the storage tank 1 by increasing the circulation flow rate. When the remaining quantity of hot water fails to exceed the specific quantity in the specific time zone and a non-specific time zone, the controller 21 reduces the circulation flow rate and stores the hot water by the specific quantity from the upper part of the hot water storage tank 1 in the shape of a stratified layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater for heating and boiling hot water in a hot water storage tank by using a heating tank different from the hot water storage tank.

[0002]

2. Description of the Related Art Conventionally, an electric water heater of this type has a structure in which water is supplied from the lower part and hot water is supplied from the upper part as described in, for example, Japanese Utility Model Publication No. 2-4368 or Japanese Patent Publication No. 3-38507. Equipped with a push-up hot water storage tank,
A circulation path is connected to the upper and lower parts of this hot water storage tank, and a heating tank having a heater is arranged in this circulation path, and normal temperature water supplied to the lower part of the hot water storage tank through the circulation path is passed through the heating tank and A circulation pump that circulates to the top is provided.

Then, the heater is turned on and the circulation pump is rotated at a constant speed, and the room temperature water supplied to the lower part of the hot water storage tank is heated to a predetermined temperature by the heater and boiled back to the upper part of the hot water storage tank to return to the upper part of the hot water storage tank. A predetermined amount of hot water is stored from the side. Therefore, when hot water is supplied,
The hot water stored in the upper part of the hot water storage tank is supplied.

The constant rotation of the circulation pump is set so as to obtain a circulation flow rate capable of boiling water of, for example, 10 ° C. supplied to the lower portion of the hot water storage tank to 85 ° C. in the heating tank.

[0005]

By the way, in the conventional electric water heater, even when all the hot water in the hot water storage tank is boiled, the hot water is stored in a stratified manner from the upper side of the hot water storage tank as described above. Go. In this case, when the hot water storage layer is in the upper layer of the hot water storage tank, the water in the lower part of the hot water storage tank flowing to the heating tank is at room temperature, but when the hot water storage layer approaches the lower side of the hot water storage tank, the lower part of the hot water storage tank The temperature of hot and cold water in the heating tank rises, and the temperature of the hot and cold water flowing in the heating tank rises.

As described above, when the temperature of the hot water flowing into the heating tank rises, the hot water flowing into the heating tank is circulated at a circulating flow rate capable of boiling up to a predetermined temperature in the heating tank based on the low temperature as described above. Therefore, the boiling water is boiled in the heating tank, and the boiled water is returned to the upper part of the hot water storage tank.

When boiling of hot water occurs, there is a problem that the internal pressure of the circulation tank or the like rises due to the vaporization (vaporization) pressure and steam flows through the hot water supply pipe, and the piping material (especially a pipe made of heat-resistant vinyl chloride) Etc.), the sealing material, packing, etc. deteriorate.

If the hot water is left for a long time without being used for a long time, the heat of the hot water remaining is also affected by heat conduction in the room temperature water supplied to the lower part. While the temperature rises, the temperature of the remaining hot water itself also drops. For this reason, even when additional heating is performed to raise the temperature of the hot water to a predetermined temperature, hot water having a temperature lower than the predetermined temperature but in a raised state flows into the heating tank, and thus a boiling problem similarly occurs.

The present invention has been made in view of the above circumstances, and prevents the boiling water in the heating tank from boiling by changing the circulating flow rate in accordance with the amount of remaining hot water in the hot water tank, and is desired to be used. An object of the present invention is to provide an electric water heater that can quickly store hot water in the upper part of a hot water storage tank.

[0010]

According to the present invention, there is provided a hot water storage tank for supplying water from a lower portion and hot water from an upper portion, a heating tank having a heater connected to upper and lower portions of the hot water storage tank via a circulation path, and the hot water storage tank. A circulation pump that circulates the hot and cold water in the tank from the lower part of the hot water storage tank to the upper part of the hot water storage tank through the heating tank, the residual hot water amount detection means that detects the residual hot water amount in the hot water storage tank, and the midnight power time zone. When the remaining hot water amount detected by the remaining hot water amount detecting means is equal to or more than a predetermined amount during the specific time period including the time zone detecting means including the hot water storage tank, the circulation flow rate by the circulation pump is increased. When the total amount of hot and cold water in the interior is raised and the amount of remaining hot water becomes less than or equal to a predetermined amount during the specific time period and the time period other than the specific time period, the circulation flow rate is reduced to store hot water. From the upper side of the tank to the stratified form is obtained and a control unit for a predetermined amount hot water storage.

[0011]

According to the present invention, when the amount of remaining hot water is below a predetermined amount during a specific time period such as the midnight power time period, the circulating flow rate is reduced to allow a predetermined amount of hot water to be stored in a stratified form from the upper side of the hot water storage tank. If the amount of remaining hot water in the hot water storage tank is more than a predetermined amount, the circulating flow rate of the circulation pump is increased to raise the total amount of hot water in the hot water storage tank. Prevents boiling water from boiling in the heating tank due to an increase in circulation flow rate.

Further, in a time zone other than a specific time zone such as the daytime zone, if the remaining hot water amount becomes a predetermined amount or less, the circulating flow rate is reduced to store a predetermined amount of hot water in a stratified form from the upper side of the hot water storage tank, which can be used. Prepare the hot water by storing it in the upper part of the hot water storage tank as soon as possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a hot water storage tank, a water supply pipe 2 directly connected to a water pipe is connected to a lower part of the hot water storage tank 1, and a hot water supply pipe 4 having a hot water tap 3 is connected to an upper part thereof. A hot water supply system with a push-up method that uses tap water pressure is adopted.

On the side surface of the hot water storage tank 1, a plurality of temperature sensors 5a, 5b, 5c of the residual hot water amount detecting means 5 are attached at upper, middle and lower height positions, respectively, and
A temperature sensor 6 is attached to the lower portion of the hot water storage tank 1 in the vicinity of the connection portion of the water supply pipe 2. The residual hot water amount detecting means 5
The hot water temperature at each height position of the hot water storage tank 1 detected by each temperature sensor 5a, 5b, 5c is detected, and the control unit 21 described later determines the residual hot water amount from each detected temperature.

A circulation path 11 consisting of a circulation pipe is connected to the upper and lower parts of the hot water storage tank 1, and a circulation pump 12 for circulating hot water from the lower part to the upper part of the hot water storage tank 1 is connected in the middle of the circulation path 11. A heating tank 13 is disposed on the discharge side of the circulation pump 12 while being disposed. A heater 14 is provided inside the heating tank 13, and a temperature sensor 15 is attached near the discharge side to the circulation path 11.

Next, 21 is a control unit, and this control unit 21 has
An A / D converter 22 that A / D-converts and outputs the detection signals of the temperature sensors 5a, 5b, 5c, 6, 15 is connected, and an operation unit 23 that inputs and inputs various setting items is connected. A display unit 24 that displays the operating state and the like is connected.

The control unit 21 is connected to an AC commercial power source to stop the operation of the circulation pump 12 and control the rotation speed, and also controls the output unit 25 which controls the energization of the heater 14 to control the midnight power time period. A detection signal is input from the time zone detection means 26 for detecting a specific time zone.

The time zone detecting means 26 detects that the timer switch is turned on and the power is automatically turned on when a specific time zone such as a midnight power time zone is reached. In addition, when the hourly charge is applied, the amount of electric power used is individually settled in an integrated watt-hour meter that distinguishes the electric power used in the specific time zone and the time zone other than that.

Further, the control unit 21 is a control pattern memory.
27, a moving time memory 28 and a water temperature memory 29 are connected.

The control pattern memory 27 stores the control pattern of the boiling temperature required according to the temperature of the water supplied to the lower portion of the storage tank 1 to the desired boiling temperature value such as the standard boiling temperature or the higher boiling temperature. Multiple types are stored according to.

The moving time memory 28 stores the moving time for delaying the energization start time to the circulation pump 12 and the heater 14 according to the temperature of the water supplied to the lower part of the storage tank 1, the control pattern and the amount of remaining hot water. The reason for setting this moving time is that when boiling is possible within a specific time zone, boiling is started at the same time as entering the specific time zone. Since it takes a long time to stop using hot water outside the specified time period and heat is radiated from the hot water, delay the energization start time so that the boiling is completed at the end of the specific time period. Shorten the time to use.

The water temperature memory 29 stores the boiling temperature corresponding to the selected control pattern and movement time, and the water supply temperature of the day detected by the temperature sensor 6 necessary for determining this temperature.

Then, if the remaining hot water amount detected by the remaining hot water amount detecting means 5 is equal to or more than a predetermined amount in the specific time zone, the control unit 21 increases the circulation flow rate by the circulation pump 12 to raise the entire inside of the hot water storage tank 1. When the amount of remaining hot water becomes less than or equal to a predetermined amount in a specific time zone and a time period other than the specific time zone, the function of reducing the circulation flow rate and storing a predetermined amount of hot water in a stratified manner from the upper side of the hot water storage tank 1 is provided. It is equipped with a timer function.

Next, the control operation by the control unit 21 will be described with reference to the flow chart of FIG. 2 by taking the application of the hourly charge system as an example.

It is judged whether it is a specific time zone such as a daytime time zone or a midnight power time zone (step 1), and if it is a specific time zone, the control pattern is selectively read from the control pattern memory 27 (step 2). ). The selective reading of this control pattern reads the boiling temperature corresponding to the control pattern selected and specified by the operation unit 23 according to the water supply temperature of the day stored in the water temperature memory 29 and stores it in the water temperature memory 29. To do.

At the same time, it is determined whether or not the current amount of remaining hot water in the hot water storage tank 1 is equal to or more than a predetermined amount (step 3). If the amount is equal to or more than the predetermined amount, it is determined whether a moving time needs to be set (step 4). ), If necessary, the moving time is selectively read from the moving time memory 28, and a timer of the control unit 21 for measuring the moving time is started (step 5). The necessity of setting the moving time and the selective reading are determined by the feed water temperature, the control pattern, and the remaining hot water amount.

When the timer of the control unit 21 counts up the moving time (step 6), the timer is reset (step 7), the heater 14 of the heating tank 13 is turned on (step 8), and at the same time, circulation is performed. The pump 12 is driven to rotate at high speed (step 9).

Therefore, by using hot water, the hot water storage tank 1
The room temperature water supplied to the lower part of the hot water or the hot water not used as the residual hot water is heated in the heating tank 13 and circulated to the upper part of the hot water storage tank 1. Since the circulation flow rate per unit time at that time is large, the entire inside of the hot water storage tank 1 is agitated and gradually heated and boiled.

By the way, as the heating and boiling progresses, the temperature of the hot water flowing from the hot water storage tank 1 to the heating tank 13 rises, but the circulating flow rate of the hot water is large, and the hot water is stored before the hot water boils in the heating tank 13. Since it flows to the tank 1 side, boiling water does not boil.

A temperature sensor provided in the heating tank 13
15 or the temperature sensor 6 in the hot water storage tank 1 detects that the hot water temperature has risen to the set temperature (step 1
0), turn off heater 14 (step 11), and circulate pump 12
Is turned off (step 12).

Next, when the amount of remaining hot water is less than the predetermined amount in step 3 or when it is not necessary to set the moving time in step 4, the heater 14 is turned on (step 1
3) At the same time, the circulation pump 12 is driven to rotate at a low speed (step 14).

Therefore, the room temperature water supplied to the lower portion of the hot water storage tank 1 is heated in the heating tank 13 and circulated to the upper portion of the hot water storage tank 1. Since the circulation flow rate per unit time at that time is small, the hot water heated in the heating tank 13 is stored in a stratified form from the upper side of the hot water storage tank 1.

When the amount of hot water stored in the upper part of the hot water storage tank 1, that is, the amount of remaining hot water becomes a predetermined amount or more (step 15), from that time until an appropriately set set time elapses (step 16), In this operating state, heating hot water storage is continued.

This set time is set in preparation for the use of hot water in a specific time zone, and even if the required amount of remaining hot water is secured, if the whole amount of boiling water immediately starts, The hot water in the upper part of the hot water storage tank 1 is agitated with the room temperature water in the lower part before boiling to prevent the inconvenience of a sudden change in hot water temperature. If the entire amount boiling operation is delayed for about 1 hour, the bathing during this time period will not be hindered. If this time zone is displayed on the display unit 24 to inform the user that it is a bathing time zone for additional heating, the convenience is further improved.

When the set time is reached in step 16, the process proceeds to step 9 and, as described above, the circulation pump 12 is switched to the high speed rotation drive, and the whole amount boiling operation is started.

Next, at step 1, if it is a daytime time zone other than the specific time zone, the routine proceeds to step 17. This daytime time zone is when the hot and cold water boiled in a specific time zone is used most, and considering the convenience when hot water shortage occurs before entering the next specific time zone, the daytime time zone is considered. However, additional heating setting means is provided so that additional heating can be performed.

If the reheating setting is made (step 17), it is constantly monitored whether the amount of remaining hot water in the hot water storage tank 1 is equal to or more than a predetermined amount (step 18).

When it is judged that the amount of remaining hot water is less than the predetermined amount,
The heater 14 is turned on (step 19), and at the same time, the circulation pump 12 is driven to rotate at a low speed (step 20). Therefore, the room temperature water supplied to the lower portion of the hot water storage tank 1 is heated in the heating tank 13 and circulated to the upper portion of the hot water storage tank 1.
Since the circulation flow rate per unit time at that time is small, the hot water heated in the heating tank 13 is stored in a stratified form from the upper side of the hot water storage tank 1.

When the amount of hot water stored in the upper portion of the hot water storage tank 1, that is, the amount of remaining hot water exceeds a predetermined amount (step 21), the heater 14 is turned off (step 22) and the circulation pump 12 is turned off (step 21). 23) Return to step 1 and monitor the amount of remaining hot water.

In order to increase or decrease the circulation flow rate, in addition to the rotation speed control of the circulation pump 12, a valve mechanism for varying the flow rate may be used, or both may be used together.

[0042]

According to the present invention, when the amount of remaining hot water in the hot water storage tank is a predetermined amount or more, the circulation flow rate by the circulation pump is increased to raise the total amount of hot and cold water in the hot water storage tank, and If the amount is less than a certain amount, the circulating flow rate will be reduced and the specified amount of hot water will be stored stratified from the upper side of the hot water storage tank. It is possible to prevent the boiling water from boiling in the heating tank by increasing the flow rate, and it is possible to quickly store the hot water to be used in the upper portion of the hot water storage tank when the remaining hot water amount is reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electric water heater of the present invention.

FIG. 2 is a flow chart for explaining the operation of the above embodiment.

[Explanation of symbols]

 1 Hot water storage tank 5 Residual hot water amount detection means 11 Circulation path 12 Circulation pump 13 Heating tank 14 Heater 21 Controller 26 Time zone detection means

Continued Front Page (72) Inventor Shigehiro Nagashima 1-11-15 Higashi-Gotanda, Shinagawa-ku, Tokyo Inside Toshiba Equipment Co., Ltd.

Claims (1)

[Claims] 1. A hot water storage tank for supplying water from a lower portion and hot water from an upper portion, a heating tank having a heater connected to the upper and lower portions of the hot water storage tank via a circulation path, and hot water in the hot water storage tank by the circulation path. A circulation pump that circulates from the lower part of the hot water storage tank to the upper part of the hot water storage tank through the heating tank, a residual hot water amount detection means for detecting the amount of residual hot water in the hot water storage tank, and a time for detecting a specific time zone including a midnight power time zone When the amount of remaining hot water detected by the amount of remaining hot water detected by the amount of remaining hot water detection device is equal to or more than a predetermined amount in the zone detection means and the specific time zone, the circulation flow rate by the circulation pump is increased to raise the total amount of hot water in the hot water storage tank. When the amount of remaining hot water becomes less than or equal to a predetermined amount during the specific time period and the time period other than the specific time period, the circulation flow rate is reduced to stratify from the upper side of the hot water storage tank Electric water heater, characterized in that a control unit for a predetermined amount hot water storage to.