JP2004170025A - Electric water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric water heater for performing inexpensive heating operation via a heat exchanger by providing a heating power supply for an upper heater separately from a heating power supply for a lower heater for reducing the electric power charge of the upper heater. <P>SOLUTION: The electric water heater comprises a hot water storage tank 1, a water supply pipe 2 provided at the lower part of the hot water storage tank 1, a hot water supply pipe 3 provided at the upper part of the hot water storage tank 1, the lower heater 4 provided in the hot water storage tank 1 at its lower part, the upper heater 5 provided in the hot water storage tank 1 at its upper part, and the heat exchanger 6 provided near the upper heater 5 for heat exchange between hot water in the hot water storage tank and it. A commercial power supply 7 which is preset to cut off energization at a given time is used as the heating power supply for the upper heater 5 and usual commercial power supplies 8 are used as a control power supply for the upper heater 5 and as the heating power supply and a control power supply for the lower heater 4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric water heater, in particular, by providing a heating power supply for the upper heater separately from a heating power supply for the lower heater, thereby reducing the electricity charge for the upper heater and controlling heating via a heat exchanger. The present invention relates to an electric water heater that can be performed at low cost.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a system for supplying hot water by an electric water heater using midnight power, when hot water is supplied to a bathtub, hot water set to a predetermined temperature is supplied from a hot water supply port or a faucet of the bathtub.
That is, in this electric water heater, the tap water supplied from the water pipe is heated in the hot water storage tank of the electric water heater, and the heated water is mixed directly or with the tap water from another water pipe. The temperature is adjusted to a set temperature, and the temperature-controlled hot water is supplied to a hot water supply port or a faucet via a pipe.
Also, in this electric water heater, a heat exchanger is arranged in the hot water storage tank so as to be heated by using hot water having a relatively high temperature at an upper portion, and the heat medium in the heat exchanger is circulated so that the hot water storage tank is circulated. The heat energy inside is taken out and used for heating.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional electric water heater, inexpensive midnight power is used as a power source for heating the lower heater, and hot water is stored in the hot water storage tank at midnight, while the temperature of the upper part of the hot water storage tank is reduced by the action of the heat exchanger and the like. When it falls, the hot water in the upper part of the hot water storage tank is heated by the upper heater.
In this case, the heating power supply of the upper heater is the same as that of the lower heater, but since the usage time is real-time, it is not possible to use the late-night power as in the lower heater, and as a result, the electricity charge increases. Have a problem.
[0004]
The present invention has been made in view of the above-mentioned problems of the conventional electric water heater, and provides a heating power supply for the upper heater separately from a heating power supply for the lower heater. It is an object of the present invention to provide an electric water heater that can perform heating or the like at low cost.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the electric water heater of the present invention comprises a hot water storage tank, a water supply pipe provided at a lower part of the hot water storage tank, a hot water supply pipe provided at an upper part of the hot water storage tank, and a lower part within the hot water storage tank. An electric water heater comprising: a lower heater provided; an upper heater provided in an upper portion of the hot water storage tank; and a heat exchanger provided near the upper heater and performing heat exchange between hot water in the hot water storage tank. In the power supply for heating the upper heater, a commercial power supply that is set in advance so as to cut off the power supply at a predetermined time is used, and the power supply for controlling the upper heater and the power supply for heating and controlling the lower heater are usually used. Characterized in that a commercial power supply is used.
[0006]
This electric water heater uses, as a heating power supply for the upper heater, a commercial power supply that is set in advance so as to cut off the power supply at a predetermined time, a power supply for controlling the upper heater, a power supply for heating the lower heater, and a power supply for controlling the lower heater. Since a normal commercial power supply is used as the power supply, for example, an inexpensive power supply such as a power supply for snow melting can be used as a power supply for heating the upper heater, thereby reducing a power charge for the upper heater. Heating via a heat exchanger can be performed at low cost.
[0007]
In this case, the pressure in the heat exchanger can be set lower than the pressure in the hot water storage tank.
[0008]
Thereby, even if the piping of the heat exchanger is damaged, it is possible to prevent the heat medium of the heat exchanger from leaking into the hot water storage tank.
[0009]
Also, the hot water supply pipe can be provided above the upper heater.
[0010]
Thereby, the temperature of hot water supplied from the hot water supply pipe can be increased.
[0011]
Further, the capacity of the hot water storage tank above the upper heater can be set to １ ／ to の of the entire hot water storage tank.
[0012]
Thereby, the heat capacity used for the heat exchanger can be increased without increasing the capacity of the hot water storage tank.
[0013]
Further, the output of the upper heater can be set to 1.1 to 1.2 times the load of the heat exchanger.
[0014]
This makes it possible to efficiently use heat energy and reduce running costs.
[0015]
Further, when the temperature near the heat exchanger in the hot water storage tank falls below a predetermined value, the circulating pump of the heat exchanger can be stopped.
[0016]
Thereby, the operation of the electric water heater can be stabilized with priority given to hot water supply.
[0017]
Further, the heat output of the upper heater can be controlled by proportional control such as thyristor phase control.
[0018]
Thereby, the average temperature of the hot water heated by the upper heater can be increased.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an electric water heater of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 shows an embodiment of the electric water heater of the present invention.
[0021]
The electric water heater includes a cylindrical hot water storage tank 1 having a required capacity, a water supply pipe 2 provided at a lower part of the hot water storage tank 1, a hot water supply pipe 3 provided at an upper part of the hot water storage tank 1, and a hot water storage tank. 1, heat exchange is performed between a lower heater 4 provided at a lower part in the hot water storage tank 1, an upper heater 5 provided at an upper part in the hot water storage tank 1, and hot water of the hot water storage tank 1 provided near the upper heater 5. And a heat exchanger 6 for heating the radiator 11 of the indoor unit for heating.
This electric water heater uses a commercial power supply 7 preset to cut off the power supply at a predetermined time, as a heating power supply for the upper heater 5, and also operates a control device 7 a of the upper heater 5. An ordinary commercial power supply 8 is used as a control power supply for controlling the lower heater 4 and a control power supply for operating the lower heater 8 control device 8a.
This electric water heater is used not only for heating the radiator 11 of the indoor unit for heating described above, but also for use in which an electric water heater is conventionally used, such as hot water supply to a bath 13 and a faucet 14. Things.
[0022]
In this case, the pressure in the heat exchanger 6 is set lower than the pressure in the hot water storage tank 1, so that even if the piping of the heat exchanger 6 is damaged, the hot water storage tank 1 for the heat medium in the heat exchanger 6 is damaged. We try to prevent leakage into the inside.
The hot water supply pipe 3 is provided above the upper heater 5, thereby increasing the temperature of hot water from the hot water supply pipe 3.
In addition, as shown in FIG. 1, the hot water flowing out of the hot water supply pipe 3 is mixed with water from a pipe or a water pipe from the lower part of the hot water storage tank, temperature is adjusted, and then the hot water is discharged from a bath or a faucet.
[0023]
The capacity of the hot water storage tank 1 above the upper heater 5 is set to １ ／ to の of the entire hot water storage tank 1, whereby the heat exchanger 6 can be used without increasing the capacity of the hot water storage tank 1. To increase the heat capacity used.
Further, the output of the upper heater 5 is set to be 1.1 to 1.2 times the load of the heat exchanger 6, thereby efficiently utilizing heat energy and reducing running costs.
[0024]
When the temperature in the vicinity of the heat exchanger 6 in the hot water storage tank 1 falls below a predetermined value, the circulation pump of the heat exchanger 6 is set to be stopped. It is trying to stabilize the operation of the water heater.
The heat output of the upper heater 5 is controlled by proportional control such as thyristor phase control, so that the average temperature of hot water heated by the upper heater 5 is increased.
[0025]
On the other hand, as shown in FIG. 1, the heat exchanger 6 is connected to a radiator 11 of a heating indoor unit via a heat medium pipe 9 and a circulation pump 10.
Further, a temperature sensor (not shown) attached to the hot water storage tank 1 can quickly and accurately detect a decrease in temperature, and appropriately perform additional heating by the upper heater 5 as necessary. be able to.
In addition, at an appropriate position of the heat medium pipe 9 (in this embodiment, between the heat exchanger 6 and the circulation pump 10), an expansion tank 12 that absorbs a change in volume of the heat medium circulating in the heat medium pipe 9 is provided. To be installed.
[0026]
By the way, the inexpensive commercial power source 7 used as a power source for heating the upper heater 5 includes, for example, a power source for snow melting in Hokkaido and the like.
As the power source for snow melting, for example, “Hot time 22” of Hokkaido Electric Power Co., Ltd., in which power supply is intermittently interrupted by a time switch so that the total interruption time is 2 hours within a peak time from 16:00 to 21:00. And so on.
In this system, the power can be used almost all day, but the power supply is cut off for two hours for a total time as described above, and the power supply cutoff time is shifted in each home, thereby averaging the power consumption peak. , And to reduce the electricity charge.
[0027]
Next, an example of a method of using the electric water heater of the present embodiment will be described with reference to FIG.
First, the method for determining the ON / OFF temperature of the upper heater 5 for heating is that the snow melting power source 7 and the normal commercial power source 8 (late night rate) have a difference in unit price. Only the commercial power source 8 of the late night charge is used without being used.
However, if the snow melting power supply 7 is stopped at night, the heating capacity may be insufficient. Therefore, the ON / OFF temperature of the upper heater 5 is lowered at night, and the lower heater 4 is mainly operated at low cost at midnight. The power is supplied by the commercial power supply 8 at a charge, and the upper heater 5 is supplied with the power for snow melting 7 only when the heating capacity is still insufficient.
As a result, the electric water heater of the present embodiment can lower the electricity charge as compared with the conventional method of using the electric water heater shown in FIG.
[0028]
Further, the inverter control (semiconductor relay / thyristor) of the upper heater 5 will be described.
When the temperature of the heat medium of the heating radiator 11 is increased by the heat exchanger 6, the temperature of the entire hot water storage tank 1 (the upper hot water other than the incoming water when hot water is separately used) decreases. .
Even if the upper heater 5 is energized in order to raise the temperature of the dropped hot water, only the temperature above the upper heater 5 can be raised among the hot water in the upper part of the hot water storage tank.
Therefore, if the ON / OFF temperature width of the upper heater 5 is set to be as wide as usual, an intermediate temperature layer (a layer having a slightly weak temperature) is formed between the upper heater 5 and the water below the hot water storage tank.
Therefore, the necessary calories are continuously generated by making the ON / OFF temperature width of the upper heater 5 particularly narrow or changing the amount of generated heat by inverter control or the like.
Since there is a problem with the conventional electromagnetic relay, a semiconductor relay (thyristor) is used to cope with this.
Thus, high-temperature hot water that is not lubricious can be used even when a large amount of hot water is supplied.
[0029]
Thus, the electric water heater according to the present embodiment uses the commercial power source 7 that is set in advance so as to cut off the power supply at a predetermined time as the heating power source for the upper heater 5, the control power source for the upper heater 5, and the lower power source. Since the normal commercial power supply 8 is used as the heating power supply and the control power supply for the heater 4, an inexpensive power supply such as a snow melting power supply can be used as the heating power supply for the upper heater 5. In addition, it is possible to reduce the electricity charge of the upper heater 5 and to perform heating and the like via the heat exchanger 6 at low cost.
[0030]
As described above, the electric water heater according to the present invention has been described based on the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the configuration may be appropriately changed without departing from the gist thereof. can do.
[0031]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the electric water heater of this invention, while using the commercial power supply preset so that the electric power may be cut off at a predetermined time, the power supply for controlling the upper heater and the heating power supply for the lower heater are used as the heating power supply for the upper heater. Since a normal commercial power source is used as the power source and the control power source, an inexpensive power source such as a snow melting power source can be used as a power source for heating the upper heater. , Heating and the like via the heat exchanger can be performed at low cost, and at the same time, it can contribute to averaging the peak of power consumption.
[0032]
In addition, by setting the pressure in the heat exchanger lower than the pressure in the hot water storage tank, even if the pipe of the heat exchanger is damaged, it is possible to prevent the heat medium of the heat exchanger from leaking into the hot water storage tank. it can.
[0033]
Further, by providing the hot water supply pipe above the upper heater, the temperature of hot water from the hot water supply pipe can be increased.
[0034]
Further, by setting the capacity of the hot water storage tank above the upper heater to 1/4 to 1/2 of the entire hot water storage tank, the heat capacity used for the heat exchanger can be increased without increasing the capacity of the hot water storage tank. Can be.
[0035]
In addition, by setting the output of the upper heater to be 1.1 to 1.2 times the load of the heat exchanger, the thermal energy can be efficiently used and the running cost can be reduced.
[0036]
In addition, when the temperature near the heat exchanger in the hot water storage tank drops below a predetermined value, the operation of the electric water heater is stabilized by giving priority to hot water supply by stopping the circulation pump of the heat exchanger. Can be.
[0037]
Further, by performing the thermal output of the upper heater by proportional control such as thyristor phase control, the average temperature of hot water heated by the upper heater can be increased.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing one embodiment of an electric water heater according to the present invention.
FIG. 2 is a graph showing how to use the electric water heater of the embodiment.
FIG. 3 is a graph showing a method of using a conventional electric water heater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Water supply pipe 3 Hot water supply pipe 4 Lower heater 5 Upper heater 6 Heat exchanger 7 Conditional commercial power supply 7a Control equipment 8 Normal commercial power supply 8a Control equipment 9 Heat medium piping 10 Circulation pump 11 Heating radiator 12 Expansion tank

Claims (7)

A hot water storage tank, a water supply pipe provided at a lower part of the hot water storage tank, a hot water supply pipe provided at an upper part of the hot water storage tank, a lower heater provided at a lower part of the hot water storage tank, and a water supply pipe provided at an upper part of the hot water storage tank An upper heater, and a heat exchanger provided near the upper heater and performing heat exchange between hot water in a hot water storage tank, wherein a power supply for heating the upper heater is supplied at a predetermined time. An electric hot water system, wherein a commercial power supply set in advance so as to cut off power supply is used, and a normal commercial power supply is used as a control power supply for the upper heater and a heating power supply and a control power supply for the lower heater. vessel. The electric water heater according to claim 1, wherein the pressure in the heat exchanger is set lower than the pressure in the hot water storage tank. 3. The electric water heater according to claim 1, wherein the hot water supply pipe is provided above the upper heater. 4. The electric water heater according to claim 1, wherein the capacity of the hot water storage tank above the upper heater is set to 1/4 to 1/2 of the entire hot water storage tank. 5. The electric water heater according to claim 1, wherein the output of the upper heater is set to be 1.1 to 1.2 times the load of the heat exchanger. The circulating pump of the heat exchanger is stopped when the temperature near the heat exchanger in the hot water storage tank falls below a predetermined value. Electric water heater. 7. The electric water heater according to claim 1, wherein the heat output of the upper heater is controlled by proportional control such as thyristor phase control.

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