JP2006329581A - Electric water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric water heater capable of reducing an energy charge by providing a heating power source for an upper heater separately from a heating power source for a heat pump, and applying a current only to the heat pump utilizing midnight power as much as possible in a midnight power time zone. <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 heat pump 4 for heating water in the hot water storage tank 1; and the upper heater 5 provided at an upper part in the hot water storage tank 1. A commercial power source 7 preset to cut off current application at a predetermined time is used for the heating power source for the upper heater 5, and a normal commercial power source 8 is used for a control power source of the upper heater, and a driving power source and a control power source for the heat pump 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric water heater, and in particular, by providing a heating power source for an upper heater separately from a heating power source for a heat pump, the power charge for the upper heater is reduced, and heating via a heat exchanger is inexpensive. The present invention relates to an electric water heater that can be used.

Conventionally, in a system in which hot water is supplied 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 outlet 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 hot water is mixed directly or with tap water from another water pipe. The temperature is adjusted to a preset temperature, and the temperature-adjusted hot water is supplied to a hot water supply port or a faucet through a pipe.
Further, in this electric water heater, a hot water storage tank is provided with a heat exchanger that is heated using hot water at a relatively high temperature in the upper part, and the heat medium in the heat exchanger is circulated. The inside heat energy is taken out and used for heating or the like (for example, see Patent Document 1).

By the way, in the above-described conventional electric water heater, inexpensive late-night power is used as a power source for driving a heat pump for heating the water in the hot water storage tank, and hot water is stored in the hot water storage tank in the middle of the night, while the heat exchanger or the like operates. When the temperature of the upper part of the hot water storage tank is lowered, the hot water in the upper part of the hot water storage tank is heated by the upper heater.
In this case, the power supply for heating the upper heater is the same as that of the heat pump. However, since the usage time is not real time but real time, there is a problem that the electric power charge increases as a result.
Japanese Patent Application Laid-Open No. 07-253246

  In view of the problems of the above-described conventional electric water heaters, the present invention provides a heating power source for the upper heater separately from the heating power source for the heat pump, and the midnight power time zone is limited to a heat pump that uses midnight power as much as possible. An object of the present invention is to provide an electric water heater that can reduce the amount of electric power charges when energized.

  In order to achieve the above object, an electric water heater of the present invention includes a hot water storage tank, a water supply pipe provided in the hot water storage tank, a hot water supply pipe provided in an upper part of the hot water storage tank, and a heat pump for heating water in the hot water storage tank. And an electric water heater having an upper heater provided in the upper part of the hot water storage tank, a commercial power source (this specification) preset so as to cut off energization at a predetermined time to the heating power source of the upper heater (Referred to as “conditional commercial power supply”), and a normal commercial power supply is used as the control power supply for the upper heater, the drive power supply for the heat pump, and the control power supply.

  In this case, the heat exchanger of the heat pump can be provided in the vicinity of the hot water storage tank.

  Moreover, the heat exchanger which performs heat exchange between the warm water of a hot water storage tank can be arrange | positioned in the vicinity of an upper heater.

  According to the electric water heater of the present invention, the power source for heating the upper heater uses a commercial power source set in advance so as to cut off energization at a predetermined time, and the power source for controlling the upper heater and the power source for driving the heat pump. Since an ordinary commercial power source is used as the control power source, for example, an inexpensive power source such as a snow melting power source can be used as a heating power source for the upper heater. It is possible to reduce heating and the like through the heat exchanger at low cost, and the electric water heater can be operated at a low running cost.

  In this case, by providing a heat exchanger for the heat pump in the vicinity of the hot water storage tank, the connection pipe between the heat pump and the hot water storage tank can be changed from the conventional water pipe to the heat medium pipe. It is no longer necessary to consider freezing on the ground, and running costs can be reduced.

Further, when a heat exchanger for exchanging heat with the hot water in the hot water storage tank is provided in the vicinity of the upper heater, the number of pumps for guiding the hot water in the upper part of the tank to the heat exchanger can be reduced.
Even if the piping of the heat exchanger is damaged, the pressure in the heat exchanger may be set lower than the pressure in the hot water storage tank in order to prevent the heat medium of the heat exchanger from leaking into the hot water storage tank. preferable.

  Hereinafter, an embodiment of an electric water heater of the present invention will be described with reference to the drawings.

1 to 2 show an embodiment of the electric water heater of the present invention.
This electric water heater includes a cylindrical hot water storage tank 1 having a required capacity, 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, and a hot water storage tank. Heat is exchanged between the heat pump 4 for heating one water, the upper heater 5 provided in the upper part of the hot water storage tank 1, and the hot water in the hot water storage tank 1 provided in the vicinity of the upper heater 5. And a heating heat exchanger 6 for heating the radiator 9 of the indoor unit.
The heating heat exchanger 6 may be provided outside the hot water storage tank 1.
In this case, even when the piping of the heating heat exchanger 6 is damaged, it is possible to completely prevent the heat medium of the heating heat exchanger 6 from leaking into the hot water storage tank 1.

The electric water heater uses a commercial power source 7 set in advance so as to cut off energization at a predetermined time as a heating power source for the upper heater 5 and operates the control device 7a of the upper heater 5. A normal commercial power supply 8 is used as the control power supply, the drive power supply for the heat pump 4, and the control power supply for operating the control device 8 a of the heat pump 4.
This electric water heater is used in addition to the above-described uses for heating the indoor unit radiator 9 for heating, as well as uses for which an electric water heater has been conventionally used, such as hot water for baths and faucets. It is.

The hot water supply pipe 3 is provided above the upper heater 5, thereby increasing the hot water supply temperature from the hot water supply pipe 3.
The hot water discharged from the hot water supply pipe 3 is mixed with the water from the lower part of the hot water storage tank or the water from the water pipe and the temperature is adjusted, and then the hot water is discharged from a bath or a faucet.
Further, as shown in FIG. 2, by providing a heat exchanger 41 of the heat pump 4 in the vicinity of the hot water storage tank 1, the connection pipe 42 between the heat pump 4 and the hot water storage tank 1 is connected to the heat medium from the water pipe shown in FIG. It can be changed to piping, which eliminates the need for consideration for freezing in winter and cold regions, and can reduce running costs.

By the way, as an inexpensive conditional commercial power supply 7 used as a heating power supply for the upper heater 5, there is, for example, a snowmelt power supply in Hokkaido or the like.
As a power source for snow melting, for example, Hokkaido Electric's “Hot Time 22” that cuts off electricity intermittently with a time switch so that the total interruption time is 2 hours within the peak time from 16:00 to 21:00. There is a system such as.
In this system, power can be used almost all day long, but the power consumption is cut off for 2 hours in the total time as described above, and the peak of power consumption is averaged by shifting the power cut-off time in each home. In addition, we are trying to reduce the electricity bill.

Next, an example of how to use the electric water heater of this embodiment will be described.
The control device 8a of the heat pump 4 and the control device 7a of the upper heater 5 detect the temperature in the hot water storage tank 1, and start energization when the temperature becomes lower than a preset temperature.
Because there is a difference in unit price between the conditional commercial power supply 7 such as a snowmelt power supply and the normal commercial power supply 8 (midnight charge), the midnight charge without using the conditional commercial power supply 7 such as a snowmelt power supply is possible at night. It is preferable to use only the commercial power source 8.
However, if the conditional commercial power source 7 such as a snow melting power source is stopped at night, the heating capacity may be insufficient, so the conditional commercial power source 7 is used so that the tank top temperature is kept constant. The water in the upper part of the tank is heated by the upper heater 5 that performs the operation.
The temperature at the bottom of the tank suddenly decreases from the time when the evening passes, and the heat pump 4 is energized with the commercial power supply 8 at a low midnight charge in a time zone in which midnight power can be used.
At this time, the upper heater 5 is continuously energized so that the tank upper temperature is not lowered and the heating capacity is not insufficient.
When the tank lower temperature rises to the same temperature as the tank upper temperature, the upper heater 5 and the heat pump 4 are turned off.

  After 7:00 am, when the power at night is no longer available, the temperature inside the tank begins to drop again due to the use of a water heater, etc., and when the tank top temperature reaches point C in FIG. Then, energization of the upper heater 5 is started from the commercial power supply 7 with conditions such as a power supply for melting snow.

  As described above, in the time zone in which midnight power can be used, the upper heater 5 and the heat pump 4 are energized by using the commercial power supply 7 with a condition such as a snowmelt power supply and the commercial power supply 8 of the midnight charge at the same time. Boil the entire internal temperature.

  As described above, the electric water heater of the present invention has been described based on the embodiments thereof, but the present invention is not limited to the configurations described in the above embodiments, and the configuration is appropriately changed without departing from the gist thereof. Is something that can be done.

  The electric water heater of the present invention uses a commercial power source set in advance so as to cut off energization at a predetermined time as a heating power source for the upper heater, and also controls the power source for controlling the upper heater and the power source for driving the heat pump. Use a normal commercial power supply for the power supply, and use the upper heater and the hot water supply exclusively with the heat pump. For example, it can be easily applied to an existing electric water heater.

It is a circuit diagram which shows one Example of the electric water heater of this invention. It is a circuit diagram which shows the example which provided the heat exchanger of the heat pump in the vicinity of the hot water storage tank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Water supply pipe 3 Hot water supply pipe 4 Heat pump 41 Heat exchanger 42 Connection piping 5 Upper heater 6 Heat exchanger for heating 7 Conditional commercial power supply 7a Control equipment 8 Normal commercial power supply 8a Control equipment 9 Heating radiator

Claims (3)

  A hot water storage tank, a water supply pipe provided in the hot water storage tank, a hot water supply pipe provided in the upper part of the hot water storage tank, a heat pump for heating the water in the hot water storage tank, and an upper heater provided in the upper part of the hot water storage tank In the electric water heater provided, the power source for heating the upper heater uses a commercial power source set in advance so as to cut off energization at a predetermined time, and the power source for controlling the upper heater, the power source for driving the heat pump, and the control An electric water heater characterized by using a normal commercial power source as a power source.   The electric water heater according to claim 1, wherein a heat exchanger of the heat pump is provided in the vicinity of the hot water storage tank.   The electric water heater according to claim 1 or 2, wherein a heat exchanger for exchanging heat with hot water in a hot water storage tank is disposed in the vicinity of the upper heater.

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