JPH07155259A - Electric hot water storage container - Google Patents

Abstract

(57) [Summary] [Purpose] An electric hot water storage container equipped with a water purification device that uses a water purification material that has a certain number of uses for water purification performance, detects when the life of the water purification material has passed, and informs the user. Inform. [Structure] A counting means for counting the number of boiling times of the electric hot water storage container, and a life of the water purifying material when the number of boiling times counted by the counting means reaches a certain number of times of use, which is the life of the water purifying material. A notifying means for notifying the user is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric hot water storage container having a water purification function.

[0002]

2. Description of the Related Art Recently, high-quality hot water with good taste is obtained by effectively removing offensive odor (2MIB: methylisoborneol), residual chlorine, organic substances, trihalomethane (chloroform), etc. in the internal solution in an electric hot water storage container. From the purpose, it has been proposed to use an electric pump for pouring the internal solution to pass through the activated carbon of the water purification unit while forcibly circulating the internal solution as necessary (for example,
(See Japanese Patent Laid-Open No. 5-7530).

In addition, a water purification unit is installed in a hot water storage container in a dipped state, and natural water convection at the time of boiling the inner solution is used to bring the activated carbon and the inner solution into contact with each other so that the water can be purified. Some have been proposed.

[0004]

The water purification material such as activated carbon as described above has a normal boiling frequency (the number of boiling times is morning, noon,
In the case of 3 times a day in the evening), the life is generally about 1 year (3 times x 365 days, about 1100 times), and when the life expires,
The adsorption performance is saturated and the water purification function is significantly reduced.
Therefore, the water purification material whose life has passed must be replaced.

However, it is almost impossible to store the use start time one by one, and even if the use start time is stored or recorded for the time being, the life is the number of uses (the number of boiling water) during that period. It greatly fluctuates depending on the energization time to the heater.

Therefore, it is generally difficult to artificially determine the proper replacement time.

[0007]

The inventions according to claims 1 to 3 of the present application have been made for the purpose of solving the problem and making the user aware of the appropriate time for replacement of the water purification material. And each is configured as follows.

(1) Structure of the Invention According to Claim 1 The electric hot water storage container according to the present invention is an electric hot water storage container provided with a water purifying device employing a water purification material having a life of a certain number of times of use in water purification. Counting means for counting the number of boiling water of the electric hot water storage container, and when the number of boiling water counted by the counting means reaches the number of times corresponding to a certain number of times of use of the water purification material, the life of the water purification material has passed. A notification means for notifying the user is provided.

(2) Structure of the invention according to claim 2 The electric hot water storage container of the present invention is based on the structure of the invention described in claim 1 above, and the number of boiling water in the same structure is the initial number of boiling water of the electric hot water storage container. It is designed to be counted on the basis of.

(3) Structure of the Invention According to Claim 3 The electric hot water storage container according to the present invention is an electric hot water storage container provided with a water purifying device that employs a water purification material having a life of a certain usage time for water purification performance. The accumulating means for accumulating the energizing time to the electric hot water storage container, and that the life of the water purifying material has passed when the energizing time accumulated by the accumulating means reaches a time corresponding to a certain usage time which is the life of the water purifying material. Is provided to the user.

[0011]

The invention described in each of claims 1 to 3 is
The following actions are achieved corresponding to the configuration.

(1) Operation of the invention according to claim 1 In the electric hot water storage container of the present invention, as described above, the electric hot water storage device is provided with a water purifying device that uses a water purifying material having a certain number of times of service life for the water purifying performance. In the container, the life of the water purification material when the number of boiling times of the electric hot water storage container and the number of boiling times counted by the counting means reaches the number of times corresponding to a certain number of times of use of the water purification material A notifying means for notifying the user that the time has passed is provided,
Sequentially count and store the number of boiling water according to the frequency of use,
When the count value reaches a value corresponding to a certain number of times of use that defines the passage of the life of the water purification material, the fact is automatically notified by the notification means to notify the user.

(2) Operation of the invention according to claim 2 In the electric hot water storage container of the present invention, in addition to the operation of the invention according to claim 1 due to its basic configuration, the number of times of boiling water is
Since the number of initial boiling times of the electric hot water storage container is counted as a reference, since the number of boiling times that does not affect the life reduction of the water purification material, such as re-heating, is not counted,
The time when the life of the water purification material is notified becomes more appropriate.

(3) Operation of the invention according to claim 3 In the electric hot water storage container of the present invention, the electric hot water storage container is equipped with a water purifying device employing a water purification material having a life of a certain usage time in water purification performance. The accumulating means for accumulating the energizing time to the electric hot water storage container, and that the life of the water purifying material has passed when the energizing time accumulated by the accumulating means reaches a time corresponding to a certain usage time which is the life of the water purifying material. Is provided for notifying the user, and the energization time to the electric hot water storage container is sequentially accumulated and stored according to the frequency of use and the boiling time, and the accumulated value defines the elapsed life of the water purifying material. When the value reaches a certain usage time, the fact is automatically notified by the notification means to notify the user.

[0015]

As a result of the above, according to the present invention, the user can always know the proper time for exchanging the water purification material without taking any method such as storing or recording. Then, if the water purification material unit is replaced accordingly, it is possible to always obtain good quality delicious hot water.

[0016]

【Example】

(1) First Embodiment FIGS. 1 and 2 show the structure of an electric hot water storage container equipped with a water purifier according to the first embodiment of the present invention, and FIGS. 3 and 4 show control of the same. Circuitry and control operations are shown.

In this embodiment, the present invention is applied to, for example, an air pump type electric hot water storage container B.

The electric hot water storage container B comprises, as shown in FIG. 1, for example, a container body 1 and a lid body 2 which is rotatably supported on an upper portion of the container body 1.

The container body 1 is provided with a cylindrical sheet metal outer case 3 forming an outer peripheral surface and a stainless steel inner container 4 forming an inner peripheral surface, and the bottom surface of the outer case 3 is The bottom is covered with a synthetic resin bottom member 5 having a cylindrical shape.

An upwardly convex disc portion 4a is formed in the central portion of the bottom surface of the inner container 4, and the lower surface of the disc portion 4a heats the liquid content contained in the inner container 4. A boiling water heater 6A is additionally provided. And the inner container 4
A temperature sensor 38 having a heat-sensitive portion 38a in contact with the lower surface of the inner container 4 is provided at the bottom of the.

At a position near the periphery of the bottom surface of the inner container 4 (that is, the outer peripheral portion of the disc portion 4a), an inlet 7a of a liquid pouring passage 7 for pouring the content liquid to the outside is opened. It has been confused. The liquid pouring passage 7 is communicated with a pouring outlet 8 provided on one side of the upper portion of the container body 1 via a water level sensor. Reference numeral 9 is an electric circuit storage box provided with a control circuit as shown in FIG.
10 is a heat shield plate.

On the other hand, although not shown, the lid body 2 has a bellows type air pump for pumping pressurized air into the inner container 4 therein.

That is, the electric hot water storage container B in this embodiment
In the above, after the content liquid contained in the inner container 4 is boiled and heated by the heater 6A to be boiled, it is held in a heat retaining state by a heat retaining heater (not shown), and if necessary, the bellows type air pump is When operated, the contents liquid is compressed by the pressurized air sent from the air pump.
(That is, hot water) is poured out from the pouring outlet 8 through the liquid pouring passage 7.

In the case of this embodiment, the water purifier A is
Is detachably attached to the liquid outlet passage inlet 7a, which is opened at the inner bottom portion of the container body 1 (specifically, the inner container 4), via attachment means (described in detail later). As shown in FIG. 2, the heat-resistant heat-shielding container 12 having upper and lower water passages 14 and 15 is provided.
A water purifier main body 11 having a replaceable water purifying unit 13 disposed therein, and an attachment means 16 for detachably attaching the water purifier main body 11 to the inner bottom portion of the container main body 1 are configured. There is.

The heat shield container 12 comprises a bottomed cylindrical stainless steel main body 17, and an upper opening 17a of the main body 17 is covered with a cap 18. The cap 18 is a ring 2 made of synthetic resin that is in contact with the upper opening 17a of the main body 17 via a spacer 19.
0 and a stainless cover 21 that covers the outer peripheral side of the ring 20. The cover 21 is provided with the above-mentioned upper water passages 14, 14. Further, the above-mentioned lower water passages 15, 15, ... Are provided at the bottom of the main body 17. In addition, one of the lower water passages 15, 15 ... Is formed at the center of the bottom of the main body 17, and the mounting means 16 is provided as described later.
Will also be used as the derivation part.

On the other hand, the water purification unit 13 has a mesh member 2 at the upper and lower ends of a cylindrical case 22 made of synthetic resin.
3, 24 are arranged and fixed, and the space between the mesh members 23, 24 is filled with heat-resistant activated carbon 25.
Here, as the heat-resistant activated carbon 25, for example, synthetic resin activated carbon obtained by baking Bakelite is used.

The water purification unit 13 is disposed and supported in the heat shield container 12 as follows.

That is, an inwardly projecting annular projecting portion 26 is integrally formed in the middle part of the side surface of the main body 17 of the heat insulating container 12, while a pair of upper and lower parts are provided on the outer periphery of the cylindrical case 22 in the water purification unit 13. Convex ribs 27, 27 are integrally formed, the annular protrusion 26 is fitted between the convex ribs 27, 27, and in this state, the cap 18 is covered with the upper opening 17a of the main body 17. As a result, the water purification unit 13 is supported and fixed in the heat shield container 12. Therefore, the space S is interposed between the outer periphery of the water purification unit 13 and the heat shield container 12. By having such a configuration,
The heat blocking effect to the water purification unit 13 is improved, the fluidity of the content liquid flowing through the water purifier body 11 is improved, and the water purification unit 13 is easily assembled in the heat blocking container 12.

Further, a supporting plate 29 having through holes 28, 28 ... Is fixed to the lower end of the cylindrical case 22 in the water purifying unit 13, and mounting means for the supporting plate 29 will be described later. 16 are to be supported.

The attachment means 16 is a substantially U-shaped spring member having a coiled portion 16a at its lower end, and further has a horizontal fixed portion fixed to the support plate 29 at its upper end. Portions 16b, 16b are formed.
Then, the spring member 16 is inserted into the liquid pouring passage inlet 7a opening at the inner bottom portion of the container body 1 in a state in which the expansion urging force is held, and is supported by the expansion urging force. ing. With such a mounting structure, only the two spring members 16 made of steel material are present in the liquid pouring passage inlet 7a, and there is no concern that the resistance during liquid pouring will increase. .

With the above configuration, in the electric hot water storage container B of this embodiment, the content liquid circulates and flows in the water purifier A by utilizing the convection phenomenon of the content liquid caused by the heating action of the heater 6A for boiling water. Therefore, the purified water of the content liquid (that is, the removal of chlorine, methylisoborneol, trihalomethane, etc.) can be performed very efficiently without requiring the power for circulating the content liquid.

Further, as described above, when the water purifier A is attached to the liquid pouring passage inlet 7a, the liquid pouring passage inlet 7a is positioned on the peripheral side of the inner bottom portion of the inner container 4. Therefore, it is most suitable for circulating the content liquid in the water purifier A by utilizing the convection phenomenon that occurs when the content liquid contained in the inner container 4 is heated by the water and heated by the heater 6A.

Further, if the mounting structure as described above is adopted,
Since the water purifier A is located directly above the heater 6A for boiling water and is exposed to a high temperature when it is cooked in the air, the water purification unit 13 is housed in the heat shield container 12, so that the water purification unit is disposed. The influence of heat (for example, thermal deformation) on 13 is prevented, and the durability can be improved.

Further, in the case of the present embodiment, the attachment of the water purifier A to the bottom of the container body 1 is completed by one-touch operation of inserting the spring member 16 into the liquid outlet passage inlet 7a, and the spring member 16 is also inserted. Can be removed simply by pulling against the urging force, the water purifier A does not drop even when the residual liquid is discharged from the container body 1, and the water purifier A can be replaced at the time of replacement with a one-touch operation. You can do it.

Next, the electric hot water storage container B is provided with a control circuit such as a water heater as shown in FIG.

In the figure, reference numeral 6A is the above water heater, 6B.
Is a heat-retaining heater not shown in the above, and is connected to the water heater 6A via the relay switch RS and to the heat-retaining heater 6B via the triac 32.
The AC power input is supplied from 1.

The relay switch RS is a relay drive circuit 3
ON, O by relay coil RL excited by 6
The FF is controlled to control the energization state of the boiling water heater 6A, while the triac 32 has its firing angle controlled by the triac drive circuit 35 to arbitrarily control the amount of electric power supplied to the heat retaining heater 6B. Has become.

Further, reference numeral 30 is a microcomputer control unit, and the water temperature data TW of the temperature sensor 38 detected through the heat sensitive portion 38a, operation signals of operation keys such as a timer key and a reboil / descaling key ( (ON, OFF signal) to determine the water supply state, the water supply temperature, the reboiler / descaling, etc., and actuate the relay drive circuit 36 or the triac drive circuit 35 in accordance with the determination result. Such control is performed, and the display element 40 is driven to perform necessary display, for example, a timer lamp (3 types of 9 hours, 6 hours, and 3 hours), water amount (full water, water supply), boiling state,
In addition to displaying the bleaching state, the heat retention state, etc., as will be described later, the number of ON-OFF times of the water heater 6A is counted and stored, and the activated carbon 25 is exchanged when the activated carbon 25 replacement time comes based on the count value. The timing alarm 41 is activated to inform the user to replace the activated carbon 25 (water purification unit 13).

Further, reference numeral 37 is a frequency synchronizing signal input circuit for detecting the power supply frequency (50/60 Hz) of the AC power supply and inputting it to the microcomputer control unit 30.
The microcomputer control unit 30 inputs the frequency synchronization signal and the detection signal of the temperature sensor 38 in synchronization with each other,
The amount of water is determined, and the heating time of the water heater 6A corresponding to the amount of water is controlled. The same frequency synchronization signal is also used as a reference signal for timer counting.

Next, the contents of the boiling water heater control and the activated carbon replacement timing notification control of the embodiment of the present invention performed by the microcomputer control unit 30 will be described in detail with reference to the flowchart of FIG.

That is, first, after the control is started (after the power is turned on),
In step S ₁ , the water temperature detection data T of the temperature sensor 38 is obtained.
Enter W. Then, the operation signal (ON / OFF signal) of the operation key such as the reboil key is input.

Then, in step S ₃ , it is determined whether or not the value of the water temperature TW is less than or equal to the reference value TW ₁ for boiling the water by turning on the heater 6A.

As a result, if YES, step S ₄
Proceed to step 1 to turn on the heater 6A to start heating, while confirming that the reboil key has not been turned on at step S ₅ , and when the boiling is completed, turn on the heater 6A at step S _6. Turn it off.

[0044] Then, in step S ₇ in response to OFF of the kettle heater 6A, the initial kettle number counting counter count one dose increments the Cn of (Cn + 1), and the count value after the count-up at Step S ₈ C is the number of initial boiling times corresponding to the life of the activated carbon 25 (saturation of adsorption performance) 1100 (3 times a day × 365 days = 1095 times ≈
(1100 times), it is finally advanced to step S ₉ to activate the replacement timing notification alarm 41 to notify the user that the activated carbon 25 has reached the replacement time after the end of its life. .

As a result, the user can accurately recognize that the activated carbon 25 of the water purifier A has reached the time of replacement without relying on memory or the like, and the electric hot water storage container should always have an effective water purification function. Is possible.

(2) Second Embodiment Next, the flow chart of FIG. 5 shows the contents of the boiling water heater control and the activated carbon replacement timing notification control of the electric hot water storage container equipped with the water purifier according to the second embodiment of the present invention. .

In this embodiment, the structure of the hardware part is basically the same as that of the first embodiment, but the judgment of the end of life is made on the basis of the total energization time to the heater 6A. It is characterized by that.

Therefore, the contents of the boiling water heater control and the activated carbon replacement timing notification control of the second embodiment performed by the same microcomputer control unit 30 as in FIG. 3 will be described in detail with reference to the flowchart of FIG.

That is, first, after the control is started (after the power is turned on),
In step S ₁ , the water temperature detection data T of the temperature sensor 38 is obtained.
Enter W. Then, the operation signal (ON / OFF signal) of the operation key such as the reboil key is input.

Then, in step S ₃ , it is determined whether or not the value of the water temperature TW is equal to or lower than the reference value TW ₁ at which the water heater 6A should be turned on to start the water heating.

As a result, if YES, then step S ₄
At the same time to the kettle heater 6A to ON to start the boiler willing to, turns ON the energization timer for measuring an energization time t to the boiler heaters 6A at step S _5.

[0052] Thereafter, step S ₆ whether the kettle heater 6A and kettle is completed is turned OFF
In determines, when it is determined that turned OFF, it is turned OFF the energization timer at step S ₇ in synchronization.

When it is determined in step S ₈ that the count value t of the energization timer has reached the total initial boiling time t ₁ corresponding to the life of the activated carbon 25 (saturation of adsorption performance), finally, the process proceeds to step S _9, the user is notified that the time to replace it by operating the replacement timing notification alarm 41 passed the life of the activated carbon 25.

As a result, the user can accurately recognize that the activated carbon 25 of the water purifier A has reached the time of replacement without relying on memory or the like, and the electric hot water storage container should always have an effective water purification function. Is possible.

(3) Third Embodiment FIGS. 6 to 9 show the structure of an electric hot water storage container with a water purifier equipped with a forced circulation means for forcibly circulating water during boiling according to a third embodiment of the present invention. The control action is shown.

Also in the present embodiment, as shown in FIG. 6, in the lower portion of the side wall of the inner container 4, the offensive odor, residual chlorine, organic matter, trihalomethane, etc. in the inner solution W stored in the inner container 4 are kept. A water purifier 50 for adsorbing and removing is attached detachably. The water purifier 50 is configured by filling activated carbon 85 into a case 82 having openings 84 and 81 serving as inlets and outlets for the inner solution, and a connecting pipe 56 is connected to the bottom center of the case 82. There is. In the case of this embodiment, the activated carbon 85 has excellent heat resistance similar to the above.
(For example, synthetic resin activated carbon obtained by baking Bakelite) is adopted. Further, reference numeral 83 is a mesh net for preventing the activated carbon 85 from flowing out.

Then, the connecting pipe 86 is connected to the inner container 4
Pump pipe side connection pipe 5 fixed through the bottom of the bottom wall
The water purifier 50 can be attached and detached by removably fitting and inserting the water purifier.

The connecting pipe 51 extends upward in the space between the side wall of the inner container 4 and the outer case 7, and the inner container 4 side outlet 46c is located above the full water level in the inner container 4. A forced circulation pipe 46b that is exposed is connected, and a pumping pump 42 is interposed in the middle of the forced circulation pipe 46b as a forced circulation means driven by a motor. That is, in this embodiment,
The forced circulation pipe 46b and the pumping pump 42 constitute a forced circulation means for drawing out the inner solution W that has passed through the water purifier 50 and returning it to the inner container 4 again.

In the case of this embodiment, for example, a pump capable of rotating in both forward and reverse directions is adopted as the pumping pump 42 constituting the above-mentioned forced circulation means. It is supposed to be used for water purification as well.

The pumping pump 42 of this embodiment is shown in FIG.
As shown in FIG. 2, the pump casing 43, the impeller 45 disposed in the pump casing 43 and driven to rotate by the reversible motor 44, and the two discharge ports 43 a and 43 b in the pump casing 43 are connected to the liquid pouring passage. 46a side and the forced circulation pipe outlet 46b side, respectively, are provided with communication passages 47 and 48, and a diaphragm type switching valve 49 that selectively opens and closes the communication passages 47 and 48. . A connection pipe 51 (that is, the inlet side 46d of the forced circulation pipe 46b) into which a water purifier 50 described later is inserted is connected to a suction port 52 formed at an appropriate position of the pump casing 43. Further, reference numeral 53,
54 is a switching valve 49 in the middle of the communication passages 47, 48.
The communication hole 55 is opened and closed by the reference numeral 55, and a spring 55 urges the switching valve 49 toward the communication hole 54. That is, in the pumping pump 42 of the present embodiment, the switching valve 49 causes the switching valve 49 to communicate with the communication hole 54 or 53 as the impeller 45 rotates in the forward direction (that is, the arrow M direction) or in the reverse direction (that is, the arrow N direction). Alternatively, the inner solution W can be selectively discharged to the liquid discharge passage 46a side or the forced circulation pipe outlet 46b side.

The reversible motor 44 in this embodiment is shown in FIG.
Drive control is performed by a motor drive circuit connected as shown in FIG.

In FIG. 6, reference numeral 61 is a heat retention heater, and 6
2 is a triac for heat insulation, 63 is a tyre, 64,6
5 is a capacitor, 66, 67 are Zener diodes, 68,
69 is a transistor and 70 is a resistor.

In this electric circuit, the transistor 68 is turned on (at this time, the transistor 69 is turned on).
In the FF state), a circuit indicated by the reference symbol LA is formed to positively rotate the reversible motor 42 and discharge it from the pumping pump 42 to the liquid pouring passage 46a side, while the transistor 6
9 is turned on (at this time, the transistor 68 is off)
By doing so, the circuit indicated by the symbol LB is configured to reversely rotate the reversible motor 44, and the pumping pump 42 discharges the forced circulation pipe 46b to the outlet 46c side thereof.

In the case of the present embodiment, by rotating the pumping pump 42 forward and backward, the internal solution can be poured out through the liquid pouring passage 46a or the forced circulation water can be purified when boiling water through the forced circulation pipe 46b. It is supposed to be. Therefore, in the case of the present embodiment, the inner solution W passes through the water purifier 50 even when the liquid is poured out, and the water purifying action at that time can be expected.

The electric hot water storage container is also provided with an activated carbon replacement timing notification control circuit having the same microcomputer control unit as in the first embodiment, and activated carbon replacement timing notification control as shown in the flowchart of FIG. 9 is performed. Done.

That is, in the control, first, step S ₁
Input the ON / OFF signal of the reversible motor 44 with
In the subsequent step S ₂ , it is determined whether or not the reversible motor 44 is turned on. When it is determined that the reversible motor 44 is turned on, the reversible motor 44 is turned on in step S _3.
The count value Cn of the counter that counts the number of times is incremented by one (Cn + 1), and the process proceeds to step S ₄ .

Then, in step S ₄ , the total count value C of the counter is a value corresponding to the life of the activated carbon of the water purifier 1100 times (3 times / day × 365 = 1095 times ≈
1100 times), and if the answer is YES, the process proceeds to step S ₅ , where the replacement timing alarm 41 is activated to replace the activated carbon after the life of the activated carbon has passed. Notify the user that it is time.

As a result, also in this structure, the same effect as that of the first and second embodiments can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an electric hot water storage container according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a water purifier portion of the electric hot water storage container.

FIG. 3 is a system block diagram showing a configuration of a control circuit unit of the electric hot water storage container.

FIG. 4 is a flowchart showing the contents of the boiling water and activated carbon replacement timing notification control of the electric hot water storage container.

FIG. 5 is a flowchart showing the contents of hot water boiling and activated carbon replacement timing notification control of the electric hot water container according to the second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a configuration of an electric hot water container according to a third embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view of a pumping pump section of the electric hot water storage container.

FIG. 8 is an electric circuit diagram showing a configuration of a motor drive circuit of the electric hot water storage container.

FIG. 9 is a flowchart showing the contents of activated carbon replacement timing notification control for the electric hot water storage container.

[Explanation of symbols]

6A is a water heater, 30 is a microcomputer control unit, 3
Reference numeral 1 is an AC power source, 32 is a triac, 38 is a temperature sensor, 40 is a display element, and 41 is an activated carbon replacement timing notification alarm.

Claims (3)

[Claims] 1. An electric hot water storage container comprising a water purifying device that employs a water purification material having a certain number of uses of water purification performance, and a counting means for counting the number of boiling times of the electric hot water storage container and the counting means. An electric hot water storage provided with an informing means for informing the user that the life of the water purification material has passed when the counted number of times of boiling water reaches a number of times corresponding to a certain number of times of use, which is the life of the water purification material. container. 2. The electric hot water storage container according to claim 1, wherein the number of boiling water is counted on the basis of the number of initial boiling water. 3. An electric hot water storage container provided with a water purifying device that uses a water purification material having a life of a certain usage time for water purification performance, and integrating means for integrating the energization time to the electric hot water storage container, and the integrating means. The electricity supplying means for notifying the user that the life of the water purification material has passed when the energized time accumulated by Hot water storage container.