Field of the Invention
The present invention relates to a power interchange
system which allows an interchange of an electric power,
which is generated by a power generation device, between
power consuming dwellings in a multi-family house.
Background of the Invention
In recent years, there is an increasing number of
dwellings which generate respective electric powers by
themselves with solar cells or fuel cells. However, there
is a case where an amount of a power produced through the
self-power generation exceeds an amount of a consumed
electric power. In this case, a surplus power is discarded.
Therefore, a technique for interchanging the surplus power
between dwellings is suggested (e.g., Japanese patent
application publication No. 2006-288162).
Summary of the Invention
However, the power transmission between power
consuming dwellings is performed through an electric wire
through which a commercial AC power is transmitted, thus
making it difficult to clearly identify a usage ratio
between the amount of the commercial AC power and the amount
of the electric power interchanged between the dwellings.
In view of the above, the present invention provides a
power interchange system capable of clearly identifying a
ratio between an amount of an electric power interchanged
among power consuming dwellings and an amount of a
commercial AC power for interchanging the electric power.
In accordance with an aspect of the present invention,
there is provided a power interchange system for
interchanging an electric power, which is generated by a
power generation device, between power consuming dwellings
in a multi-family house.
The respective power consuming dwellings generate
respective electric powers by using the power generation
devices and are supplied with a commercial AC power through
a shared power supply wiring. An amount of an electric
power supplied to each power consuming dwelling is managed
by a power management device. Further, the power management
device manages an amount of a surplus power of one power
consuming dwelling and an amount of a required power of
another power consuming dwelling and supplies the surplus
power from the one power consuming dwelling to the another
power consuming dwelling through the power supply wiring.
With such configuration, the power management device
recognizes the surplus power amount of the one power
consuming dwelling and the required power amount of another
power consuming dwelling when the surplus power of the one
power consuming dwelling is supplied to the another power
consuming dwelling. Accordingly, a ratio between the amount
of electric power traded between power consuming dwellings
and the amount of commercial AC power used by each power
consuming dwelling is clearly identified.
An amount of an electric power sold by each power
consuming dwelling may be defined as a selling power amount,
and an amount of an electric power required to be supplied
from other power consuming dwellings to each power consuming
dwelling is defined as a purchasing power amount.
Each of the power consuming dwellings preferably
includes the power generation device for generating the
electric power and a power control unit calculating the
selling power amount based on the amount of the electric
power generated by the power generation device and
transmitting to and receiving from the power management
device selling power amount information indicating the
selling power amount and purchasing power amount information
indicating the purchasing power amount.
The power management device may establish a trade in an
electric power between the power consuming dwellings based
on the selling power amount information and the purchasing
power amount information; instruct a power consuming
dwelling, which has transmitted the selling power amount
information, to sell an electric power based on the
established trade in the electric power; collect information
on the amount of commercial AC power supplied from the power
supply wiring to the multi-family house, the selling power
amount of each power consuming dwelling, and the purchasing
power amount of each power consuming dwelling; and calculate
an electricity billing rate of each power consuming dwelling
based on the amount of the commercial AC power, the selling
power amount and the purchasing power amount.
When the electric power is traded between power
consuming dwellings in the multi-family house, it is unfair
on a power consuming dwelling selling the electric power, a
power consuming dwelling purchasing the electric power, and
a power consuming dwelling not involved in trading power to
calculate the electricity bill of each power consuming
dwelling proportionally to the amount of commercial AC power
MC consumed by the power consuming dwelling. With such
configuration, the power management device collects the
information on the amount of the commercial AC power, the
selling power amount of each power consuming dwelling, and
the purchasing power amount of each power consuming dwelling
and calculates the electricity bill of each power consuming
dwelling based on the amount of commercial AC power MC, the
selling power amount, and the purchasing power amount. That
is, since the electricity bill of each dwelling is
calculated based on the amount of commercial AC power, the
selling power amount, and the purchasing power amount, the
electricity bill can be shared fairly by the power consuming
dwellings.
A current sensor detecting a flowing direction of the
commercial AC power may be provided between a downstream
wiring of the power supply wiring inside the multi-family
house and an upstream wiring thereof outside the multi-
family house 130. The power management device preferably
distinguishes a used state of the commercial power from a
non-used state of the commercial power, the non-used state
of the commercial power being defined as a state in which
the current sensor detects that there is no electric current
flowing from the upstream wiring to the downstream wiring
and the used state of the commercial power being defined as
a state in which the current sensor detects that there is an
electric current flowing from the upstream wiring to the
downstream wiring. The power management device may set a
difference between an electricity billing rate for an amount
of an electric power used by each power consuming dwelling
in the non-used state of the commercial power and an
electricity billing rate for an amount of an electric power
used by each power consuming dwelling in the used state of
the commercial power.
The difference in the electricity bill between in the
non-used state of commercial AC power and in the used state
of commercial AC power is set to motivate the power
consuming dwellings to determine in which state of the non-
used state and the used state of the commercial AC power
they consume a greater amount of power.
The power generation device preferably include a
variety of kinds of power generation devices, and the power
management device may manage the selling power amount by
distinguishing which of the power generation devices are
used to generate the electric power.
With such configuration, since the selling powers of
power consuming dwellings are differently managed based on
power generation devices that produce the selling powers,
information can be processed based on the kind of the power
generation device which generates the selling power. For
example, a power consuming dwelling purchasing a selling
power can be provided with information on the kind of a
power generation device which produced the selling power, or
a different price of the power can be set depending on the
kind of the power generation device.
The electricity billing rate is preferably changed
depending on the kind of a power generation device that is a
power source of the electric power sold when calculating the
electricity bill of each power consuming- dwelling based on
the amount of the commercial AC power, the selling power
amount, and the purchasing power amount.
Accordingly, since the electricity billing rate is set
to a different value depending on the kind of an electricity
generation source of the selling power, the power consuming
dwelling can actively use power from an electricity
generation source providing a lower price than the other
electricity generation sources.
Each of the power consuming dwellings further includes
a display unit displaying an electricity billing rate for
the commercial AC power and an electricity billing rate for
the trade in the electric power.
With such configuration, the electricity billing rate
for the commercial AC power and for the trade in the
electric power is displayed to the power consuming
dwellings. The power consuming dwellings can compare the
electricity billing rate for the commercial AC power with
that for the power trade to determine whether to use the
commercial AC power or to trade the electric power.
The power generation device may be shared by the power
consuming dwellings.
Each of the power consuming dwellings includes a
storage battery charged with an electric power distributed
from the power generation device and a battery charger
charging the storage battery with the electric power from
the power generation device and transmitting charging
information for a charging control to the power management
device.
.The power management device may manage the amount of
the electric power distributed from the power generation
device to the storage battery of each power consuming
dwelling based on the charging information from the battery
charger.
With such configuration, since the power management
device manages the amount of the electric power distributed
from the power generation device to the storage battery of
each power consuming dwelling, the amount of power
distributed to each power consuming dwelling is clarified.
Thus, a ratio between the amount of power distributed to
each power consuming dwelling and the amount of commercial
AC power used by each power consuming dwelling is clearly
identified.
An amount of an electric power sold by each power
consuming dwelling may be defined as a selling power amount,
and an amount of an electric power required to be supplied
from other power consuming dwellings to each power consuming
dwelling may be defined as a purchasing power amount.
Each of the power consuming dwellings includes a power
control unit calculating the selling power amount based on
the amount of the electric power accumulated in the storage
battery and transmitting to and receiving from the power
management device selling power amount information
indicating the selling power amount and purchasing power
amount information indicating the purchasing power amount.
The power management device preferably manages a
charging level that is the charging information from the
battery charger, the selling power amount and the purchasing
power amount from the power control unit.
Accordingly, since the power management device manages
the charging level of a battery charger of each power
consuming dwelling and the selling power amount and the
purchasing power amount thereof, it is possible to control
the amount of power distributed to each power consuming
dwelling based on such information.
A charging allowance condition determining whether or
not to allow charging from the power generation device is
set to the storage battery of each power consuming dwelling,
and the power management device allows the storage battery
to be charged when the storage battery of the power
consuming dwelling satisfies the charging allowance
condition.
With such configuration, a storage battery of each
power consuming dwelling which satisfies the charging
allowance condition is allowed to be charged, whereas a
storage battery which does not satisfy the charging
allowance condition is not allowed to be charged. That is,
the power generated by a power generation device is not
evenly distributed to the storage batteries of power
consuming dwellings but distributed '-¦ only to storage
batteries which satisfy the respective 'charging allowance
conditions. Accordingly, as compared with when the
generated power is uniformly distributed, unnecessary
distribution of the power to a storage which does not need
charging is prevented.
A selling allowance condition determining whether or
not to allow selling the electric power from the storage
battery to the power supply wiring may be set to the storage
battery of each power consuming dwelling, and the power
management device preferably allows selling the electric
power from the storage battery when the corresponding
storage battery of the power consuming dwelling satisfies
the selling allowance condition.
Accordingly, selling power is allowed from the storage
battery which satisfies the selling allowance condition
among the storage batteries of power consuming dwellings,
whereas selling power is not allowed from the storage
battery which does not satisfy the selling allowance
condition. In this way, the sale of powers from the storage
batteries of the power consuming dwellings is managed, so
that the charging levels of the storage batteries of the
power consuming dwellings are properly identified.
The power management device may manage the numbers of
charging and discharging of the storage battery of each
power consuming dwelling and calculate a life span of the
storage battery based on the numbers of the charging and
discharging.
The abrasion of a storage battery depends on how much
it is used. With such configuration, the power management
device manages the numbers of the charging and discharging
of the storage battery of each power consuming dwelling and
calculates the life span of the storage battery, thus
recognizing how much the storage battery is worn out.
The power management device preferably establishes a
trade in an electric power between power consuming dwellings
based on the selling power amount information and the
purchasing power amount information; instructs a power
consuming dwelling, which has transmitted the selling power
amount information, to sell an electric power based on the
established trade in the electric power; collects
information on the amount of commercial AC power supplied
from the power supply wiring to the multi-family house, the
selling power amount of each power consuming dwelling, and
the purchasing power amount of each power consuming
dwelling; and calculates an electricity billing rate of each
power consuming dwelling based on the amount of the
commercial AC power, the selling power amount, and the
purchasing power amount.
There is a difference in the charged amount of power
between the storage batteries of the power consuming
dwellings. Thus, even though a power from a shared power
generation device is uniformly distributed, the power may
not be effectively utilized. However, with such
configuration, since the trade in the electric power enables
the power accumulated in the storage battery of one power
consuming dwelling to be re-distributed to another power
consuming dwelling, electric power is effectively used.
Further, since the electricity bill of each power consuming
dwelling is calculated based on the amount of commercial AC
power, the selling power amount, and the purchasing power
amount, a power consuming dwelling of a selling side can
make a profit. Accordingly, re-distribution of electric
power can be promoted.
Brief Description of the Drawings
The objects and features of the present invention will
become apparent from the following description of preferred
embodiments given in conjunction with the accompanying
drawings, in which:
Fig. 1 is a block diagram showing a schematic
configuration of a power interchange system in accordance
with a first embodiment of the present invention;
Fig. 2 is a block diagram showing a schematic
configuration of a power supply system of a dwelling in
accordance with the first embodiment;
Fig. 3 is a table showing a selling power amount and a
purchasing power amount of each dwelling, and a relationship
in a trade between dwellings in accordance with the first
embodiment;
Figs. 4A and 4B show a balance of electric power of a
power supply wiring of the power interchange system in
accordance with the first embodiment, wherein Fig. 4A is a
schematic view showing an input and an output of electric
power to and from the power supply wiring, and Fig. 4B is a
graph showing a relationship between an amount of input
power and an amount of output power;
Fig. 5 is a flowchart showing an individual billing
process performed by a control unit in accordance with the
first embodiment;
Fig. 6 is a table showing a relationship between a
power generation device and a set price of electric power in
accordance with the first embodiment;
Fig. 7 is a graph showing a relationship between a
selling power amount from a solar cell, a selling power
amount from a fuel cell, an amount of commercial AC power,
and a purchasing price in a power interchange system in
accordance with the first embodiment;
Fig. 8 is a graph showing a relationship between a
selling power amount from the solar cell, a selling power
amount from the fuel cell, a purchasing power amount, and an
individual bill as to a single dwelling in accordance the
first embodiment;
Fig. 9 is a block diagram showing a schematic
configuration of a power interchange system in accordance
with a second embodiment of the present invention; and
Fig. 10 is a graph showing a relationship between an
amount of solar cell power, a charging level of a dwelling
D, a charging level of a dwelling E, and an amount of power
distributed to each dwelling in a power interchange system
in accordance with the second embodiment.
Detailed Description of the Embodiments
Hereinafter, embodiments of the present invention will
be described with reference to the accompanying drawings
which form a part hereof. Throughout the drawings, like
reference numerals will be given to like parts, and
redundant description thereof will be omitted.
(First Embodiment)
A first embodiment of the present invention will be
described with reference to Figs. 1 to 8.
As shown in Fig. 1, a multi-family house 130, such as
a mansion, is provided with a power supply wiring 12 0. The
power supply wiring 120 is connected to a commercial AC
(Alternating Current) power source 2.
A power interchange system 100 in accordance with the
first embodiment includes the power supply wiring 120 for
supplying an electric power to each dwelling 131 and a power
management device 101 managing power supply to the dwellings
131. A shared storage battery 103 is provided at a basic
portion of the power supply wiring 120. A current sensor
102 is provided upstream from the shared storage battery 103
between a downstream wiring 122 of the power supply wiring
120 provided inside the multi-family house 130 and an
upstream wiring 121 thereof provided outside the multi-
family house 130.
The current sensor 102 detects the direction of an
electric current. When the current sensor 102 detects an
adverse current that is flowing from the multi-family house
130 to the commercial AC power source 2, a corresponding
amount of an electric power to the adverse current is
accumulated in the shared storage battery 103 from that
point. Further, the accumulated electric power is
discharged to be supplied to the power supply wiring 12 0,
e.g., when the current sensor 102 detects a current flowing
from the commercial AC power source 2 to the multi-family
house 130.
The power management device 101, the shared storage
battery 103, and the current sensor 102 are connected to an
information network 110. A dwelling 131 is provided with a
PC terminal 50 connected to the information network 110 and
a power supply system 1 controlling the electric power in
the dwelling 131.
The power supply system 1 supplies an electric power
to a variety of electrical devices (such as an illuminating
device, an air conditioner, a home appliance, an audio/video
device and the like). The power supply system 1 supplies an
electric power from a solar cell 3 generating the electric
power with the sunlight or an electric power from a fuel
cell 4 generating the electric power with fuel in addition
to supplying an electric power from a commercial AC source
(AC power source) 2 for home use to operate various kinds of
electrical devices.
The power supply system 1 is described with reference
to Fig. 2.
The power supply system 1 supplies the electric power
to not only DC appliances 5 operated with a DC power
inputted from a DC power supply but also an AC appliance 6
operated with an AC power inputted from the commercial AC
power source 2. The power supply system 1 is provided with
a control unit 7 and a DC distribution board 8 (in which a
DC breaker is arranged) . The power supply system 1 is
further provided with a controller 9 and a relay unit 10 for
controlling operations of the DC appliances 5 installed in
the dwelling.
An AC distribution board 11 for dividing an AC power
is connected to the control unit 7 through an AC power line
12. The control unit 7 is connected to the commercial AC
power source 2 via the AC distribution board 11, is
connected to the solar cell 3 through a DC power line 13a,
and is connected to the fuel cell 4 through a DC power line
13b. The control unit 7 receives an AC power from the AC
distribution board 11 and converts the AC power to a
specific DC power. Further, the control unit 7 receives DC
powers from the solar cell 3 and the fuel cell 4 and
converts the DC powers to a specific DC power. The control
unit 7 outputs the converted DC power to the DC distribution
board 8 through a DC power line 14 and to the storage
battery 16 through a DC power line 15. Furthermore, the
control unit 7 converts the DC powers from the solar cell 3,
the fuel cell 4, and the storage battery 16 to an AC power
by a grid connected inverter and supplies the power to the
AC appliance 6 through the AC distribution board 11 or
discharges the power through the power supply wiring 120.
In addition, the control unit 7 exchanges data with the DC
distribution board 8 through a signal line 17.
The DC distribution board 8 is a kind of breaker for
the DC power. The DC distribution board 8 divides the DC
power inputted from the control unit 7 and outputs the
divided DC powers to the controller 9 through a DC power
line 18 and/or to the relay unit 10 through a DC power line
19. The DC distribution board 8 exchanges data with the
controller 9 through a signal line 20 or with the relay unit
10 through a signal line 21.
The controller 9 is connected with a plurality of DC
appliances 5. The DC appliances 5 are connected to the
controller 9 through DC supply lines 22, each of which is
capable of carrying both DC power and data. Each of the DC
supply lines 22 transmits both power and data to a
corresponding DC appliance 5 over a pair of lines using,
e.g., power line communications (PLC) that overlap
communications signals for transmitting data via a high-
frequency transmission wave with the DC power to be supplied
to the DC appliance 5. The controller 9 receives a DC power
for the DC appliances 5 through the DC power line 18 and
detects operating control status of the DC appliances 5
based on an operation instruction obtained from the DC
distribution board 8 through the signal line 20. Then, the
controller 9 outputs the DC power and an operation
instruction to a designated DC appliance 5 through the
corresponding DC supply lines 22, thereby controlling the
operations of the DC appliance 5.
Switches 23 that are manipulated when the operations
of the DC appliances 5 are switched over are connected to
the controller 9 through a DC supply line 22. In addition,
a sensor 24 for detecting radio waves' transmitted from,
e.g., an infrared remote controller, is connected to the
controller 9 through the DC supply line 22. Accordingly,
the DC appliances 5 are controlled by transmitting
communications signals through the DC supply lines 22 in
response not only to the operation instruction from the DC
distribution board 8 but also to the manipulation of the
switches 23 or the detection of the sensor 24.
The relay unit 10 is connected with the plurality of
DC appliances 5 through individual DC power lines 25. The
relay unit 10 obtains a DC power for the DC appliances 5
through a DC power line 19, and determines which of the DC
appliances 5 is to be operated based on an operation
instruction obtained from the DC distribution board 8
through the signal line 21. Further, the relay unit 10
controls the operations of the DC appliances 5 determined to
be operated in such a way to have relays built therein to
turn on and off the supply of powers to the DC power lines
25. Switches 26 for manually operating the DC appliances 5
are connected to the relay unit 10, and thus, the DC
appliances 5 are controlled by manually manipulating the
switches 2 6 to have the relays to turn on or off the supply
of powers to the DC power lines 25.
A DC socket 27 installed in the dwelling in a form of,
e.g., a wall socket or a floor socket, is connected to the
DC distribution board 8 through a DC power line 28. When a
plug (not shown) of the DC appliance 5 is inserted into the
DC socket 27, it is possible to directly supply the DC power
to the DC appliance 5.
An electricity meter 29 capable of remotely measuring,
e.g., an amount of a consumed power from the commercial AC
power source 2 is connected to the AC distribution board 11.
The electricity meter 29 has not only a function of remotely
measuring the amount of the consumed power from the
commercial AC power source 2 but also, e.g., a power line
communications function or a wireless communications
function. The electricity meter 29 transmits measurement
results to an electric power company or the like through
power line communications or wireless communications.
The power supply system 1 is provided with a network
system 30 that enables various kinds of home appliances to
be controlled through network communications. The network
system 30 includes a home server 31 that functions as a
controller thereof. The home server 31 is connected to an
external home management server 32 via a network N such as
the Internet and is also connected to a home appliance 34
through a signal line 33. The home server 31 is operated by
a DC power supplied from the DC distribution board 8 through
a DC power line 35.
A control box 36 for managing the operational control
of various kinds of home appliances through network
communications is connected to the home server 31 through a
signal line 37. The control box 36 is connected to the
control unit 7 and the DC distribution board 8 through the
signal line 17. The control box 36 directly controls the DC
appliances 5 through a DC supply line 38. A gas/water meter
39 capable of remotely measuring, e.g., the amounts of gas
and tap water used, is connected to the control box 36 which
is connected to an operation panel 40 of the network system
30. A monitoring device 41 including, e.g., a door phone
outdoor unit, a sensor or a camera is connected to the
operation panel 40.
When operation instructions to operate the various
kinds of home appliances are inputted through the network N,
the home server 31 notifies the control box 36 of the
operation instructions and operates the control box 36 so
that the home appliances can be operated based on the
operation instructions. Moreover, the home server 31 can
provide various kinds of information obtained from the gas/
water meter 39 to the management server 32 through the
network N. When an abnormality detected by the monitoring
device 41 is notified to the home server 31 through the
operation panel 40, the home server 31 provides the
information on the detected abnormality to the management
server 32 through the network N.
Here, the control unit 7 will be described in detail.
The control unit 7 manages an amount of commercial AC
power MC supplied through the AC power line 12, an amount
of photovoltaic power MA generated by the solar cell 3, an
amount of fuel power MB generated by the',; fuel cell 4, and a
level of the electric power accumulated ("charging level
CL") in the storage battery 16. The control unit 7 changes
a power supply source for power supply to the AC appliance
6 or the DC appliances 5 based on the amount of the
commercial AC power MC, the amount of the photovoltaic
power MA, the amount of the fuel power MB, and the charging
level CL. For example, the control unit 7 performs a power
control as follows.
When a total amount of consumed power MR by the DC
appliances 5 and the AC appliance 6 is smaller than the
amount of the photovoltaic power MA and thus there is a
surplus amount of the photovoltaic power MA, the control
unit 7 accumulates the surplus amount of the photovoltaic
power MA into the storage battery 16. When the storage
battery 16 is fully charged, the control unit 7 stops the
storage battery 16 from being charged. When the amount of
the photovoltaic power MA is smaller than the total amount
of the consumed power MR, the control unit 7 supplies an
electric power from the storage battery 16 to the AC
appliance 6 or the DC appliances 5. When the charging
level CL of the storage battery 16 decreases to a
predetermined threshold level, the control unit 7 stops the
supply of the electric power from the storage battery 16 to
the AC appliance 6 or the DC appliances 5. The threshold
level is set in the storage battery 16 to prepare an
electric power for emergency, such as a blackout.
When the total amount of consumed power MR by the AC
appliance 6 exceeds a predefined maximum level, the control
unit 7 blocks the supply of AC power by the AC distribution
board 11. Likewise, when the total amount of power
consumed MR by the DC appliances 5 exceeds a predefined
maximum level, the control unit 7 blocks the supply of DC
power by the DC distribution board 8.
Further, the control unit 7 manages the amount of
consumed power MR, the amount of the commercial AC power MC
from the commercial AC power source 2, the amount of the
fuel power MB, the amount of the photovoltaic power MA, and
the charging level CL of the battery 16. Also, the control
unit 7 calculates an amount of an electric power which can
be sold (hereinafter, referred to as "the amount of selling
power MS") based on the above amounts. For example, the
amount of selling power MS is calculated as several tens
percent of a difference between the amount of the fuel
power MB and the amount of the photovoltaic power MA, and
the amount of consumed power MR consumed by the appliances
5 and 6. The control unit 7 calculates the amount of
required power (hereinafter, referred to as "the amount of
purchasing power MT").
Also, the control unit 7 transmits information on the
amount of selling power MS (hereinafter, referred to as
"selling power amount information") and information on the
amount of purchasing power MT (hereinafter, referred to as
"purchasing power amount information") to the power
management device 101. In addition, the control unit 7
transmits information on the kind of a power generation
device which has generated the power associated with the
amount of selling power MS along with the selling power
amount information and the purchasing power amount
information. For example, when the amount of the selling
power MS is from the photovoltaic generation, it is
transmitted as an amount of selling power from the solar
cell MSX. On the other hand, when the amount of the
selling power MS is from the fuel generation, it is
transmitted as an amount of selling power from the fuel
cell MSY.
Referring to Fig. 3, a power trade control performed
by the power management device 101 is described. Here, the
amounts of the electric power traded between dwellings A,
B, and C are illustrated. The dwelling A has a surplus of
photovoltaic power MA or a surplus of fuel power MB,
whereas the dwellings B and C exhaust the photovoltaic
power MA and the fuel power MB and thus are supplied with
an electric power from the commercial AC power source 2.
In Fig. 3, the table shows the amounts of generated power
MU, consumed power MR, and traded power by each dwelling
131 for a specified period of time, and the relationship in
a trade between dwellings 131. The amount of generated
power MU includes the total amount of the photovoltaic
power MA and the fuel power MB. The amount of selling
power MS is indicated by ( + ) in front of the amount of a
traded electric power, while the amount of purchasing power
MT is indicated by (-) in front of the amount of the traded
power.
The power management device 101 matches trade partners
based on the data listed in the table of Fig. 3. For
example, the power management device 101 establishes a
trade in an electric power between all sellers and all
buyers, and the sellers' selling power MS is distributed to
the buyers. Such trade in an electric power is performed
every predetermined period.
In the case as in the table shown in Fig. 3, the power
management device 101 establishes a trade in an electric
power between the dwellings A and B and a trade in an
electric power between the dwellings A and C. When the
trade in an electric power is established, an instruction
to discharge an electric power is sent to a seller. The
dwelling A discharges the selling power MS through the
power supply wiring 120. Accordingly, the selling power MS
flows through each dwelling 131 connected to the power
supply wiring 120. Although the destination of the selling
power MS is not determined, the selling power MS from the
dwelling A is considered to be distributed to the dwellings
B and C in the record of the power management device 101 on
the management of the power amount of each dwelling 131.
However, the dwellings B and C have power shortages even
though receiving the selling power MS. The power shortages
can be made up by purchasing power from the commercial AC
power source 2.
Referring to Figs. 4A and 4B, the relationship between
the input and the output of an electric power to and from
the power supply wiring 120 will be described.
As shown in Fig. 4A, the amount of input power MPin to
the power supply wiring 120 is the sum of the total amount
of selling powers MS from the respective dwellings 131 and
the amount of commercial AC power MC supplied from the
commercial AC power source 2 to the power supply wiring
120. The amount of output power MPout from the power
supply wiring 12 0 is the total amount of purchasing powers
MT purchased by the respective dwellings 131. As shown in
Fig. 4B, when the amount of the input power MPin to the
power supply wiring 120 is equivalent to the amount of the
output power MPout from the power supply wiring 12 0, the
balance of the electric power is maintained. Based on
this, the amount of the electric power inputted to the
power supply wiring 120 and that outputted therefrom, a
buyer and a seller engaged in the electric power trade, and
the amount of traded electric power are managed, thereby
establishing the trade in an electric power between
dwellings without confusing the amount of commercial AC
power MC and the amount of traded electric power.
The selling power MS is generated by the solar cell 3
or the fuel cell 4 and brings added value to the
environment as compared with commercial AC power. Thus, a
reasonable price is charged for the selling power
distinguished from the commercial AC power.
Referring to Fig. 5, an individual billing process
performed by the power management device 101 will be
described in detail. The billing process is carried out
every predetermined period.
First, in step S110, the amount of selling power from
the solar cell MSX is obtained from each dwelling 131. In
step S12 0, the amount of selling power from the fuel cell
MSY is obtained from each dwelling 131. In step S130, the
amount of commercial AC power MC flowing into the power
supply wiring 120 is obtained.
Subsequently, in step S140, the purchasing price Ct is
set based on the amount of selling power from the solar
cell MSX, the amount of selling power from the fuel cell
MSY, and the amount of commercial AC power MC. In step
S150, the purchasing price Ct is transmitted to each
dwelling 131 and displayed on the PC terminal 50 of each
dwelling 131. In step S160, an individual bill of each
dwelling 131 is calculated.
Fig. 6 shows prices of an electric power set by the
power generation devices.
The price of selling power from the solar cell MSX is
set to be lower than the price of selling power from the
fuel cell MSY. The price of the selling power from the
fuel cell MSY is set to be lower than the price of power
from the commercial AC power source. That is, the prices
are set to motivate a buyer to purchase the selling power
from the solar cell MSX or the selling power from the fuel
cell MSY rather than the commercial AC power MC, by
comparing the selling power from the solar cell MSX and the
selling power from the fuel cell MSY with the commercial AC
power MC. Further, a buyer is motivated to purchase the
selling power from the solar cell MSX rather than the
selling power from the fuel cell MSY, by comparing the
selling power from the solar cell MSX with the selling
power from the fuel cell MSY.'
Further, the prices of the electric powers based on
the power generation devices may be set as follows.
A case of used state of the commercial electric power
supplied to the multi-family house 130 is distinguished
from a case of a non-used state thereof, and then the price
of the electric power is set to a different level in each
case. For example, the prices of the electric powers from
the solar cell and the fuel cell are set to be lower in the
non-used state of the commercial electric power than those
in the used state of the commercial electric power. The
non-used state of the commercial electric power is defined
as a state when the current sensor 102 detects that there
is no electric power flowing from the upstream wiring 121
to the downstream wiring 122. The used state of the
commercial electric power is defined as a state when the
current sensor 102 detects that there is an electric power
flowing from the upstream wiring 121 to the downstream
wiring 122.
Referring to Fig. 7, a method of calculating the
purchasing price Ct of the electric power will be
described. The graphs in Fig. 7 show the amount of selling
power from the solar cell MSX flowing into the power supply
wiring 12 0, the amount of selling power from the fuel cell
MSY flowing thereinto, and the amount of commercial AC
power MC from the commercial AC power source 2 flowing
thereinto. The amount of selling power from the solar cell
MSX denotes the total amount of selling powers from the
solar cells MSX of the respective dwellings. The amount of
selling power from the fuel cell MSY denotes the total
amount of selling powers from the fuel cells MSY in the
respective dwellings. The amount of commercial AC power MC
denotes the amount of the power supplied from the
commercial AC power source 2 to the multi-family house 130.
The amount of selling power from the solar cell MSX
increases during the daytime. The amount of selling power
from the fuel cell MSY is nearly constant from the daytime
to the night. The amount of commercial AC power MC
increases at dawn and at night. In this way, the amounts
of the electric powers by the respective power generation
devices change with time.
The power flowing into the power supply wiring 12 0 is
distributed to the respective dwellings 131. Thus, the
purchasing price Ct is calculated as a weighted average of
the amounts of the electric powers by the various power
generation devices flowing into the power supply wiring
120, as in Equation 1 of Fig. 7.
Referring to Fig. 8, a method of calculating an
individual bill paid by each dwelling 131 will be
described. Fig. 8 shows the amount of selling power from
the solar cell MSX, the amount of selling power from the
fuel cell MSY, and the amount of purchasing power MT from
the power supply wiring 120 in a single dwelling for one
day.
In Fig. 8, the dwelling 131 sells a surplus of the
electric power generated from the solar cell 3 or the fuel
cell 4 as the selling power MS. The amount of selling
power from the solar cell MSX increases in the daytime.
The amount of selling power from the fuel cell MSY
increases through the evening. The amount of purchasing
power MT from the power supply wiring 12 0 increases at dawn
and at night.
Since a seller makes a profit when the selling power
MS is sold to another dwelling 131, the selling power is a
minus portion in the individual bill. Meanwhile, since
purchasing power MT is purchased when there occurs a
shortage of an electric power, it is a plus portion in the
individual bill. That is, the individual bill per day is
calculated by Equation 2 in Fig. 8.
The power interchange system 100 in accordance with
the first embodiment provides the following effects.
(1) In the present embodiment, the amount of the
electric power supplied to each dwelling 131 is managed by
the power management device 101. The power management
device 101 manages the amount of the selling power MS of
one dwelling 131 corresponding to the amount of surplus
power and the amount of purchasing power MT of another
dwelling 131 and sells the selling power MS of the one
dwelling 131 to the another dwelling 131 through the power
supply wiring 120.
With such configuration, the power management device
101 manages the amount of selling power MS of one dwelling
131 and the amount of purchasing power MT of another
dwelling 131 and supplies the selling power MS of the one
dwelling 131 to the another power consuming dwelling.
Accordingly, a ratio between the amount of the electric
power traded between the dwellings 131 and the amount of
commercial AC power MC used by each dwelling 131 can be
clarified.
(2) The control unit 7 calculates the amount of
selling power MS based on the amount of the electric powers
generated from the power generation devices and transmits
to and receives from the power management device 101
selling power amount information indicating the amount of
selling power MS and purchasing power amount information
indicating the amount of purchasing power MT. The power
management device 101 establishes a trade in an electric
power between dwellings 131 based on the selling power
amount information and the purchasing power amount
information from the control unit 7 and thus instructs a
seller of a dwelling 131 to sell power. Further, the power
management device 101 collects information on the amount of
commercial AC power MC supplied from the power supply
wiring 120 to the multi-family house 130, the amount of the
selling power MS of each dwelling 131, and the amount of
the purchasing power MT of each dwelling 131 and calculates
the electricity bill of each dwelling 131 based on the
amount of commercial AC power MC, the amount of the selling
power MS, and the amount of the purchasing power MT.
When the power is traded between dwellings 131, it is
unfair on a dwelling 131 selling power, a dwelling 131
purchasing power, and a dwelling 131 not involved in
trading power to calculate the electricity bill of each
dwelling 131 proportionally to the amount of commercial AC
power MC consumed by the dwelling 131. With such
configuration, the power management device 101 collects the
information on the amount of commercial AC power MC, the
amount of selling power MS of each dwelling 131, and the
amount of purchasing power MT of each dwelling 131 and
calculates the electricity bill of each dwelling 131 based
on the amount of commercial AC power MC, the amount of
selling power MS, and the amount of purchasing power MT.
That is, since the electricity bill of each dwelling 131 is
calculated based on the amount of commercial AC power MC,
the amount of selling power MS, and the amount of
purchasing power MT, the electricity bill can be calculated
fairly by the dwellings 131.
(3) In the present embodiment, the current sensor 102
for detecting the flowing direction of commercial AC power
is provided between the downstream wiring 122 of the power
supply wiring 120 provided inside the multi-family house
130 and the upstream wiring 121 thereof provided outside
the multi-family house 130. The power management device
101 distinguishes the non-used state of the commercial AC
power from the used state of the commercial AC power and
sets the electricity billing rate on the amount of the
electric power used by each dwelling 131 in the non-used
state of the commercial AC power to be different from the
electricity billing rate on the amount of the electric
power used by each dwelling 131 in the used state of the
commercial AC power.
In accordance with the present invention, the set
difference in the electricity billing rate between in the
non-used state of the commercial AC power and in the used
state of the commercial AC power can serve to motivate the
dwellings 131 to determine in which state of the non-used
state and the used state of the commercial AC power they
consume a greater amount of an electric power.
(4) In the present embodiment, the power generation
devices include two types of power generation devices, that
is, the solar cell 3 and the fuel cell 4. The power
management device 101 differently manages selling power MS
generated from the solar cell 3 and selling power MS
generated from the fuel cell 4.
With such configuration, since the selling powers MS
of each dwelling 131 generated from the solar cell 3 and
from the fuel cell 4 are differently managed, information
can be processed based on the kind of a power generation
device which generates the selling power MS. For example,
a dwelling 131 purchasing selling power MS can be provided
with information on the kind of the power generation device
which produced the selling power MS, or a different price
of an electric power can be set depending on the kind of
the power generation device.
(5) In the present embodiment, when calculating the
electricity bill based on the amount of commercial AC
power, the amount of selling power MS, and the amount of
commercial AC power MC, the electricity bill is changed
corresponding to the kind of a power generation device
generating the selling power MS.
With such configuration, since the electricity billing
rate is set to a different value depending on the kind of a
power generation source of the selling power MS, the
dwelling 131 can actively use an electric power from a
power generation source providing a lower price than the
other power generation sources.
(6) In the present embodiment, the dwellings 131 are
equipped with the PC terminals 50 as a display unit
presenting the electricity bills for commercial AC power
and for trading an electric power. With such
configuration, the electricity billing rates for a
commercial AC power and for a traded electric power can be
presented to the respective dwellings 131. Each dwelling
131 can compare the electricity billing rate for the
commercial AC power with the electricity billing rate for
the traded electric power and determine whether to use a
commercial AC power or to trade an electric power.
(Second Embodiment)
A second embodiment of the present invention will be
described with reference to Figs. 9 and 10. A power
interchange system 100 in accordance with the second
embodiment further includes the following modification in
addition to the configuration of the first embodiment.
That is, each dwelling 131 generates an electric power by
using the solar cell 3 and the fuel cell 4 in the first
embodiment, while an electric power generated by a shared
solar cell 104 provided in a multi-family house 130 is
distributed to each dwelling 131 in the second embodiment.
Hereinafter, changes from the configuration of the first
embodiment due to the modification will be described in
detail. Further, like reference numerals will be given to
like parts, and redundant description thereof will be
omitted.
As shown in Fig. 9, the multi-family house 130, such
as a mansion, is provided with a power supply wiring 120
connected to a commercial AC power source 2. Each dwelling
131 in the mansion is supplied with an electric power
through the power supply wiring 120. A storage battery 16
is provided with a battery charger 51 for charging with an
electric power from the shared solar cell 104.
The storage batteries 16 of the respective dwellings
131 are connected to the shared solar cell 104 via the
battery chargers 51. The respective battery chargers 51
are connected to the power management device 101 through an
information network 110. The battery charger 51 transmits
charging information to the power management device 101 and
receives an instruction on charging from the power
management device 101. Charging the storage batteries 16
with the electric power supplied from the shared solar cell
104 is controlled by the power management device 101. The
power management device 101 starts charging the storage
battery 16 of a specific dwelling 131 in accordance with an
instruction for start of charging and stops charging the
storage battery 16 in accordance with an instruction for
stop of charging. The charging level CL of an electric
power in the storage battery 16 of each dwelling 131 is
managed by the power management device 101.
An electric power generated from the shared solar cell
104 (hereinafter, referred to as "shared solar cell power
MAA") is distributed to the dwellings 131 through a DC
power line 105. The supply of the shared solar cell power
MMA to each dwelling 131 is started under a charging
allowance condition set for each dwelling 131, and charging
is stopped under a charging stop condition.
The charging allowance condition determines whether
the charging level CL of the storage battery 16 is a
charging allowance level which allows charging. The
charging stop condition determines whether the charging
level CL of the storage battery 16 is a charging stop
level. The charging allowance level and the charging stop
level are set to different values for the respective
dwellings 131.
When the shared solar cell 104 starts generating an
electric power, the state of the storage battery 16 of each
dwelling 131 is checked and it is determined whether
charging the storage battery 16 is possible based on the
charging allowance condition. When a dwelling 131 has the
storage battery 16 with the charging level CL that is the
charging allowance level, the storage battery 16 starts to
be charged. When a dwelling 131 has the storage battery 16
with the charging level CL that is not the charging
allowance level, the storage battery 16 is not charged.
When it is determined to stop charging based on the
charging stop condition, the charging of the storage
battery 16 is stopped.
The charging time of the storage battery 16 of each
dwelling 131 and the amount of the shared solar cell power
MAA are managed by the power management device 101. The
power management device 101 calculates the distributed
amount of the electric power from the shared solar cell 104
to each dwelling 131 and a distributed ratio thereof.
The charging levels CL of the storage batteries 16 are
different depending on the amounts of consumed powers MR by
load appliances 5 and 6 of the respective dwellings 131.
In a dwelling 131 involving a less amount of consumed power
MR, the charging level CL is maintained at a high level for
a long time.
In a dwelling 131 involving a greater amount of
consumed power MR, the charging level CL is maintained at a
high level for a reduced time. A dwelling 131 may be
supplied with an electric power from the commercial AC
power source 2, when there is a shortage of an electric
power because an electric power is not supplied from the
storage battery 16. Meanwhile, another dwelling 131 may
not consume the charged power in the storage battery 16 and
thus the storage battery has the charged power remaining.
Accordingly, in order to effectively use the power
accumulated in the storage batteries 16, the electric
powers stored in the storage batteries 16 are interchanged
between the dwellings 131.
An interchange of the electric powers stored in the
storage batteries 16 between the dwellings 131 is carried
out based on interchange conditions set for the respective
dwellings 131. The interchange conditions include two
conditions, such as a condition that the charging level CL
of the storage battery 16 of one dwelling 131 is a
dischargeable level and a condition that the charging level
CL of the storage battery 16 of another dwelling 131 is a
charging allowance level. When both conditions are
satisfied, an electric power is discharged from the storage
battery 16 with the charging level that is the
dischargeable level to the power supply wiring 120.
Further, the dischargeable level of the interchange
conditions is set with different values for the dwellings
131.
Referring to Fig. 10, the interchange of an electric
power between the dwellings 131 for one day will be
described. Herein, the interchange of an electric power
between dwellings D and E is described. The dwelling D has
a surplus of shared solar cell power MAA. The dwelling E
has consumed the entire shared solar cell power MAA and
thus is supplied with an electric power from the commercial
AC power source 2. In the dwellings D and E, the
dischargeable levels of the storage batteries 16 are set to
a threshold level CL2 or higher, and the charging allowance
levels of the storage batteries 16 are set to be less than
a threshold level CL2.
The amount of the shared solar cell power MAA
increases in the daytime. The dwelling D is supplied with
the shared solar cell power MAA from the shared solar cell
battery 104 for a period A from time t21 to time t22 as the
charging allowance condition is satisfied. When the
charging level CL of the storage battery 16 reaches a full
charge level CL1 at time t22 and the charging stop
condition is satisfied, distribution of the shared solar
cell power MAA from the shared solar cell 104 is stopped.
Here, since the charging level of the dwelling D
exceeds the threshold level CL2, it is determined that the
charging level is the dischargeable level, and accordingly
a search for a dwelling 131 satisfying the other
interchange condition is conducted. That is, the retrieval
of a dwelling 131 having the storage battery 16 with the
charging level CL that is the charging allowance level is
carried out. When there exists such a dwelling, the
interchange conditions are satisfied, and thus discharged
power MD is supplied from the storage battery 16 of the
dwelling D to the power supply wiring 120.
The dwelling E is supplied with the shared solar cell
power MAA from the shared solar cell 104 for the period A
and a period B from time t21 to time t23 as the charging
allowance condition is satisfied. Since"the dwelling E has
an amount of consumed power MR greater than the dwelling D,
an increase rate of the charging level CL is low.
Therefore, the charging level CL of the storage battery 16
of the dwelling E does not reach the threshold level CL2 at
time t22. Here, the dwelling E is at the charging
allowance level. If there is a dwelling 131 at the
dischargeable level, the dwelling E is supplied with an
electric power from the corresponding dwelling 131. In
Fig. 10, the dwelling D is at the dischargeable level, and
thus the dwelling E is supplied with the electric power
discharged from the storage battery 16 of the dwelling D.
The amounts of the shared solar cell power MAA
distributed to the dwellings D and E are as follows.
The amount of the shared solar cell power MAA
distributed to the dwelling D is a difference between the
amount of the electric power distributed from the shared
solar cell 104 for the period A and the amount of the
discharged power MD at the time t22, as shown in Equation
3. The amount of the power distributed from the shared
solar cell 104 for the period A is obtained by dividing the
amount of the shared solar cell power MAA by the number N
of the dwellings 131 receiving the same amount of
distributed power for the period A. Since the number N
changes with time, it is expressed by a function of time t.
The amount of the shared solar cell power MAA
distributed to the dwelling E is the sum of the amount of
the electric power from the shared solar cell 104
distributed to the dwelling E for the periods A and B and
the amount of the electric power supplied from the dwelling
D, as shown in Equation 4. The amount of the power
supplied from the dwelling D is obtained by dividing the
amount of the discharged power MD by the number Nx of
dwellings 131 provided with the electric power from the
dwelling D for the same periods.
The electricity billing rate of each dwelling 131 for
the use of the shared solar cell power MAA is calculated by
multiplying the distributed amount of the shared solar cell
power MAA by the set price of the shared solar cell power
MAA.
In the interchange of the electric power between the
dwellings 131, a power trade process is conducted.
That is, each dwelling 131 calculates the amount of
selling power MS based on the amount of power accumulated
in the storage battery 16 and transmits to and receives
from the power management device 101 selling power amount
information indicating the amount of its selling power MS
and purchasing power amount information indicating the
amount of its purchasing power MT. The power management
device 101 establishes a trade in an electric power based
on the selling power amount information and the purchasing
power amount information and records the amount of selling
power MS, the amount of purchasing power'MT, and the seller
and the buyers of the electric power.
There is set a difference between the price of the
shared solar cell power MAA and the price of the electric
power from the commercial AC power source 2. For example,
the price of the shared solar cell power MAA is set to be
lower than that of the electric power from the commercial
AC power source 2. Accordingly, the use of the shared
solar cell power MAA is promoted.
However, frequent power trades via the storage
batteries 16 may cause decrease in the life of the storage
batteries 16 due to repeated charging and discharging.
Therefore, the power management device 101 manages the
number of discharging, the amount of discharged power, the
discharging time, the number of charging, the amount of
charged power, the charging time, the charging speed, and a
variation in the charging speed of each storage battery 16.
The power management device 101 calculates an estimated
life span of the storage battery 16 of each dwelling 131
based on such data. The estimated life spans of the
storage batteries 16 are displayed on the respective PC
terminals 50 through the information network 110.
The power interchange system 100 in accordance with
the second embodiment can provide the following effects in
addition to the effect 1 provided by the first embodiment.
(7) In the present embodiment, the shared solar cell
104 is shared by the dwellings 131. The dwellings 131
include the respective storage batteries 16 for storing the
electric powers distributed from the shared solar cell 104
and the respective battery chargers 51 for controlling
charging the storage batteries 16 with the electric powers
from the shared solar cell 104 and transmitting charging
information on the control of charging. The power
management device 101 manages the amounts of the powers
distributed from the shared solar cell 104 to the storage
batteries 16 of the dwellings 131 based on the charging
information from the batter chargers 51.
With such configuration, since the power management
device 101 manages the amounts of powers distributed from
the shared solar cell 104 to the storage batteries 16 of
the dwellings 131, the amount of power distributed to each
dwelling 131 is clarified. Thus, a ratio between the
amount of power distributed to each dwelling 131 and the
amount of commercial AC power used by each dwelling 131 is
clearly identified.
(8) In the present embodiment, each dwelling 131
includes the control unit 7 which calculates the amount of
the selling power MS based on the amount of the electric
power stored in the storage battery 16 and transmits to and
receives from the power management device 101 the selling
power amount information indicating the" amount of selling
power MS and the purchasing power amount information
indicating the amount of the purchasing power MT. The
electric management device 101 manages the charging level
CL that is charging information from each battery charger
51, and the amount of selling power . MS and the amount of
purchasing power MT from each control unit 7.
With such configuration, since the power management
device 101 manages the charging levels CL of the battery-
chargers 51 of the dwellings 131 and the amounts of the
selling powers MS and the amounts of the purchasing powers
MT thereof, it is possible to control the amount of power
distributed to each dwelling 131 based on such information.
(9) In the present embodiment, the charging allowance
condition for determining whether or not to allow charging
from the shared solar cell 104 is set to the storage
battery 16 of each dwelling 131. The power management
device 101 allows the storage battery 16 to be charged when
the storage battery 16 of the dwelling 131 satisfy the
charging allowance condition.
With such configuration, the power generated from the
shared solar cell 104 is not evenly distributed to the
storage batteries 16 of the dwellings 131 but distributed
limitedly to storage batteries 16 which satisfy the
charging allowance conditions. Accordingly, as compared
with when the generated power is uniformly distributed,
unnecessary distribution of the power to a storage battery
16 which is not allowed to be charged is prevented.
(10) In the present embodiment, a selling allowance
condition for determining whether or not to allow the sale
of the electric power from the storage battery 16 to the
power supply wiring 120 is set to the storage battery 16 of
each dwelling 131. The power management device 101 allows
the sale of the electric power from the storage battery 16
of a dwelling 131 when the corresponding storage battery
16 satisfies the selling allowance condition.
With such configuration, selling a power is allowed
from a storage battery 16 which satisfies the selling
allowance condition among the storage batteries 16 of the
dwellings 131, whereas selling a power is not allowed from
a storage battery 16 which does not satisfy the selling
allowance condition. In this way, the sale of the power
from the storage battery 16 of each dwelling 131 is
managed, so that the charging level CL of the storage
battery 16 of each dwelling 131 is properly identified.
(11) In the present embodiment, the power management
device 101 manages the number of charging and discharging
of the storage battery 16 of each dwelling 131 and
calculates the life span of the storage battery 16 based on
the number of the charging and discharging.
The abrasion of a storage battery 16 depends on how
much it is used. With such configuration, the power
management device 101 manages the numbers of the charging
and discharging of the storage battery 16 of each dwelling
131 and calculates the life span of the storage battery 16,
thus recognizing how much the storage battery 16 is worn
out.
(Other embodiments)
The present invention is not limited to the
embodiments illustrated above. For example, the respective
embodiments may be modified as follows. Further, a
combination of the first embodiment and the second
embodiment may be employed in the present invention. The
following modifications are applied not only to the
respective embodiments, but the modifications may be
combined with each other.
In the first embodiment, the PC terminals 50 of the
respective dwellings 131 are connected to the information
network 110. Alternatively, the PC terminals 50 may be
connected to respective control units 7, and information on
the selling price of purchasing power Ct, selling power
amount information, and purchasing power amount information
may be displayed on the PC terminals 50.
In the first embodiment, the PC terminals 50 and the
control units 7 of the respective dwellings 131, the shared
storage battery 103, and the power management device 101
are connected through the information network 110.
Alternatively, these devices may be configured to exchange
information with each other via the Internet.
In the first embodiment, the price of power from the
commercial AC power source 2 is set to a constant value.
Alternatively, when there are different market prices for a
power from the commercial AC power source 2, the price of
the power may be set accordingly. For example, when the
price of the power from the commercial AC power source 2
varies in the daytime and at night, the price of purchasing
power Ct and the individual billing rate may be set
accordingly.
In the first embodiment, the price of the selling
power from the solar cell MSX is set to be lower than the
price of the power generated by another power generation
device. Alternatively, the prices may be set in the
reverse way. When there is a high demand for a power from
the solar cell, a trade in a power is realized even if the
price of the selling power from the solar cell MSX is set
to be higher than the price of the power generated by
another power generation device. In this case, an
investment in facilities for the solar cell 3 can be
collected in a short time.
In the first embodiment, when selling a power, the
power is discharged from the solar cell 3 to the power
supply wiring 120. Instead, the same selling power MS may
be discharged via the storage battery 16. With such
configuration, since the storage battery 16 serves as a
buffer, the selling power MS can be supplied to a purchaser
with a more uniform power as compared with when the power
is discharged directly from the solar cell 3.
In the first embodiment, the trade in a power is
established whenever buying and selling of a power take
place. Instead, the trade in a power may be conducted only
at specific time. For example, the power trade may be
performed at the time when the amount of a power generated
by the solar cell 3 reaches the maximum level.
In the first embodiment, each dwelling 131 is provided
with the solar cell 3 and the fuel cell 4. Alternatively,
the multi-family house 130 includes a dwelling 131 provided
with either one of the power generation devices or a
dwelling 131 without any power generation device. The
dwelling 131 without the power generation device cannot be
a seller in trading power but can be a buyer.
In the first embodiment, the dwellings 131 do not
share a power generation device. Alternatively, the
dwellings 131 may have a shared solar cell 3 or shared fuel
cell 4. The amount of power flowing from the shared solar
cell 3 or shared fuel cell 4 to the power supply wiring 120
(hereinafter, "the amount of shared power") corresponds to
the amount of input power MPin in Fig. 4. That is, the
shared power may be treated as the selling power MS.
In the second embodiment, the electricity billing rate
of each dwelling is calculated by multiplying the
distributed amount of the shared solar cell power MAA by
the set price of the shared solar cell power MAA. Instead,
the electricity payment may be calculated as in the first
embodiment. That is, the power management device 101
collects information on the amount of commercial AC power
supplied from the power supply wiring 120 to the multi-
family house 130, the amount of the selling power MS of
each dwelling 131, and the amount of the purchasing power
MT of each dwelling 131 and calculates the electricity
billing rate of each dwelling 131 based on the amount of
the commercial AC power MC, the amount of the selling power
MS, and the amount of the purchasing power MT.
In the second embodiment, since the trade in a power
enables the power accumulated in the storage battery 16 of
one dwelling 131 to be re-distributed to another dwelling
131, an electric power is effectively used. Further, since
the electricity billing rate of each dwelling 131 is
calculated based on the amount of the commercial AC power,
the amount of the selling power MS, and the amount of the
purchasing power MT, a seller dwelling 131 can make a
profit. Accordingly, re-distribution of the electric power
can be promoted.
In the second embodiment, the dwellings 131 share the
solar cell 104. Instead, the dwellings 131 may share a fuel
cell. Further, the power generation device shared by the
dwellings 131 is not limited to the solar cell 104 or the
fuel cell.
In the second embodiment, the dwellings 131 are
provided with the respective storage batteries 16.
Alternatively, the storage batteries 16 may be managed by a
manager of the multi-family house 130. In this case, the
storage batteries 16 corresponding to the respective
dwellings 131 are installed in the maintenance office of
the multi-family house.
In the respective embodiments, the power management
device 101 matches a buyer to a seller in the power trade
and conducts the trade based on the information listed in
the table. However, a seller, a buyer, and trade
conditions may be preset in the power management device 101
to automatically conduct a trade in a power under such
conditions.
In the respective embodiments, the present invention
is applied to a mansion as an illustrative example of the
multi-family house 130. That is, the present invention is
applied to a group of power consuming dwellings, such as
the mansion, provided with commercial AC power from the
shared power supply wiring 120. For example, the present
invention can be applied to a leased building or an
industrial complex.
While the invention has been shown;and described with
respect to the embodiments, the present invention is not
limited thereto. It will be understood by those skilled in
the art that various changes and modifications may be made
without departing from the scope of the invention as defined
in the following claims.
We claim:
12. A power interchange system for interchanging an
electric power, which is generated by a power
generation device, between power consuming dwellings in
a multi-family house,
wherein the respective power consuming dwellings
generate respective electric powers by using the power
generation devices and are supplied with a commercial AC
power through a shared power supply wiring,
an amount of an electric power supplied to each power
consuming dwelling is managed by a power management device,
and
the power management device manages an amount of a
surplus power of one power consuming dwelling and an amount
of a required power of another power consuming dwelling and
supplies the surplus power from the one power consuming
dwelling to the another power consuming dwelling through the
power supply wiring.
12. The power interchange system of claim 1, wherein an
amount of an electric power sold by each power
consuming dwelling is defined as a selling power
amount, and an amount of an electric power required
to be supplied from other power consuming dwellings
to each power consuming dwelling is defined as a
purchasing power amount,
each of the power consuming dwellings comprises the
power generation device for generating the electric power
and a power control unit calculating the selling power
amount based on the amount of the electric power generated
by the power generation device and transmitting to and
receiving from the power management device selling power
amount information indicating the selling power amount and
purchasing power amount information indicating the
purchasing power amount, and
the power management device establishes a trade in an
electric power between the power consuming dwellings based
on the selling power amount information and the purchasing
power amount information; instructs a power consuming
dwelling, which has transmitted the selling power amount
information, to sell an electric power based on the
established trade in the electric power; collects
information on the amount of commercial AC power supplied
from the power supply wiring to the multi-family house, the
selling power amount of each power consuming dwelling, and
the purchasing power amount of each power consuming
dwelling; and calculates an electricity billing rate of each
power consuming dwelling based on the amount of the
commercial AC power, the selling power amount and the
purchasing power amount.
3. The power interchange system of claim 2, wherein a
current sensor detecting a flowing direction of the
commercial AC power is provided between a downstream wiring
of the power supply wiring inside the multi-family house and
an upstream wiring thereof outside the multi-family house
130, and
the power management device distinguishes a used state
of the commercial power from a non-used state of the
commercial power, the non-used state of the commercial power
being defined as a state in which the current sensor detects
that there is no electric current flowing from the upstream
wiring to the downstream wiring and the used state of the
commercial power being defined as a state in which the
current sensor detects that there is an electric current
flowing from the upstream wiring to the downstream wiring
and sets a difference between an electricity billing rate
for an amount of an electric power used by each power
consuming dwelling in the non-used state of the commercial
power and an electricity billing rate for an amount of an
electric power used by each power consuming dwelling in the
used state of the commercial power.
4. The power interchange system of claim 2 or 3, wherein
the power generation device includes a variety of kinds of
power generation devices, and the power management device
manages the selling power amount by distinguishing which of
the power generation devices are used to generate the
electric power.
5. The power interchange system of claim 4, wherein the
electricity billing rate is changed depending on the kind of
a power generation device that is a power source of the
electric power sold when calculating the electricity bill of
each power consuming dwelling based on the amount of the
commercial AC power, the selling power amount, and the
purchasing power amount.
6. The power interchange system of any one of claims 2 to
5, wherein each of the power consuming dwellings further
comprises a display unit displaying an electricity billing
rate for the commercial AC power and an electricity billing
rate for the trade in the electric power.
12. The power interchange system of claim 1, wherein the
power generation device is shared by the power
consuming dwellings,
each of the power consuming dwellings comprises a
storage battery charged with an electric power distributed
from the power generation device and a battery charger
charging the storage battery with the electric power from
the power generation device and transmitting charging
information for a charging control to the power management
device, and
the power management device manages the amount of the
electric power distributed from the power generation device
to the storage battery of each power consuming dwelling
based on the charging information from the battery charger.
12. The power interchange system of claim 7, wherein an
amount of an electric power sold by each power
consuming dwelling is defined as a selling power
amount, and an amount of an electric power required
to be supplied from other power consuming dwellings
to each power consuming dwelling is defined as a
purchasing power amount,
each of the power consuming dwellings comprises a power
control unit calculating the selling power amount based on
the amount of the electric power accumulated in the storage
battery and transmitting to and receiving from the power
management device selling power amount information
indicating the selling power amount and purchasing power
amount information indicating the purchasing power amount,
and
the power management device manages a charging level
that is the charging information from the battery charger,
and the selling power amount and the purchasing power amount
from the power control unit.
9. The power interchange system of claim 7 or 8, wherein a
charging allowance condition determining whether or not to
allow charging from the power generation device is set to
the storage battery of each power consuming dwelling, and
the power management device allows the storage battery
to be charged when the storage battery of the power
consuming dwelling satisfies the charging allowance
condition.
10. The power interchange system of claim 9, wherein a
selling allowance condition determining whether or not to
allow selling the electric power from the storage battery to
the power supply wiring is set to the storage battery of
each power consuming dwelling, and
the power management device allows selling the
electric power from the storage battery when the
corresponding storage battery of the power consuming
dwelling satisfies the selling allowance condition.
11. The power interchange system of any one of claims 7 .to
10, wherein the power management device manages the numbers
of charging and discharging of the storage battery of each
power consuming dwelling and calculates a life span of the
storage battery based on the numbers of the charging and
discharging.
12. The power interchange system of any one of claims 8 to
11, wherein the power management device establishes a trade
in an electric power between power consuming dwellings based
on the selling power amount information and the purchasing
power amount information; instructs a power consuming
dwelling, which has transmitted the selling power amount
information, to sell an electric power based on the
established trade in the electric power; collects
information on the amount of commercial AC power supplied
from the power supply wiring to the multi-family house, the
selling power amount of each power consuming dwelling, and
the purchasing power amount of each power consuming
dwelling; and calculates an electricity billing rate of each
power consuming dwelling based on the amount of the
commercial AC power, the selling power amount, and the
purchasing power amount.

ABSTRACT

In a power interchange system, an electric power generated by a power generation device is interchanged
between power consuming dwellings in a multi-family house. Each power consuming dwelling generates
the power by using the power generation device and receives a commercial AC power supply via a shared
power supply wiring. The amount of electric power supplied to each power consuming dwelling is
managed by a power management device. The power management device manages a surplus power
amount of one power consuming dwelling and a required electric power amount of another power
consuming dwelling and supplies the surplus power from the former power consuming dwelling to the
latter power consuming dwelling via the power supply wiring.