KR101470545B1 - Co-generation system and a method of the same - Google Patents

Abstract

INDUSTRIAL APPLICABILITY The cogeneration system and its control method according to the present invention are configured to be able to select and use power having a low unit price among commercial power to which power generation and progressive taxes are applied so that the cost for power use can be reduced, . In addition, since the user can select the operation corresponding to the power unit cost, there is an advantage that power can be supplied at a lower cost and more conveniently in a region having a high progressive tax rate or a generation using a power amount having a high progressive tax rate.

Cogeneration, power generation, power, commercial, progressive, cost

Description

The present invention relates to a cogeneration system and a control method thereof,

The present invention relates to a cogeneration system and a control method thereof, and more particularly, to a cogeneration system and a control method thereof, in which economical efficiency and ease of use can be improved by selectively supplying power having a low unit price between generated power and commercial power .

Generally, a cogeneration system is a system that simultaneously produces power and heat from an energy source. The cogeneration system includes a generator and a drive source for driving the generator. An engine or the like may be used as the driving source. The heat generated by the drive source is supplied to a heat consumer such as a hot water supply or an air conditioner, and the electric power generated by the generator is supplied to a power consumer.

The cogeneration system is connected to the heat consumer via a heat transfer channel, and is connected to the power consumer through a power line.

The cogeneration system operates in a heat load corresponding operation mode when heat is requested in the heat consumer, and operates in a power load corresponding operation mode when power is requested in the power consumer.

However, since the cogeneration system according to the related art operates in the heat load corresponding operation mode or the power load corresponding operation mode, there is a problem that it can not cope with the fluidity of the power unit price.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cogeneration system and a control method thereof, which can improve economical efficiency and ease of use by selectively using electric power with low unit price between generated power and commercial power.

A cogeneration system according to the present invention includes a generator, a drive source for driving the generator, a heat source for generating heat, and a generator for generating power by selectively supplying one of power generation power generated from the generator and utility power supplied from an external power source A grid connection device for connecting the generator with an external power source and a power demand site; and a control unit for controlling the grid connection device and the generator so as to supply power with low unit price to the power demander, And a control unit.

Further, the present invention may further include a power unit price corresponding operation selecting unit that can be selected by the user, and when the power unit cost corresponding operation selecting unit is selected, the unit price of the generated power is compared with the commercial power, Supply to power consumers

Further, in the present invention, the control unit compares the unit price of the generated power with the unit price of the commercial power to which the progressive tax is applied.

Further, in the present invention, the user further includes an input unit for periodically inputting the unit price of the commercial power.

Further, the present invention may further include an input unit for periodically inputting a unit price of the energy source supplied to the driving source by the user, and the control unit calculates the unit price of the generated power according to the unit price of the energy source.

Further, the present invention may further include a hot water supply unit that receives heat generated from the drive source, and the control unit supplies the generated electric power to the electric power consumer when the hot water supply unit requests the hot water supply unit.

A method of controlling a cogeneration system according to the present invention includes the steps of: determining whether there is a hot water supply load; comparing a unit price of generated power generated by a generator with a unit price of commercial power supplied from an external power supply, A supply step of interrupting the supply of the external power supply, driving the generator by a power load, and supplying the generated power to the power number requesting unit when the unit price of the generated power is lower than the unit price of the commercial power .

Further, in the present invention, when it is determined that there is a hot water supply load in the hot water supply determination step, supply of the external power supply is cut off, the generator is driven by the power load, and the generated power is supplied to the power consumer.

In the present invention, when the unit price of the generated power is higher than the unit price of the commercial power in the comparison step, the supply of the generated power is cut off and the commercial power is supplied to the power consumer.

Further, in the present invention, in the comparison step, the unit price of the generated power and the unit price of the commercial power to which the progressive tax is applied are compared.

Further, in the present invention, the method further includes a selection step of the user selecting the power unit price corresponding operation mode before the hot water supply determination step, and when the power unit corresponding operation mode is selected, the hot water supply determination step is performed.

INDUSTRIAL APPLICABILITY The cogeneration system and its control method according to the present invention are configured to be able to select and use power having a low unit price among commercial power to which power generation and progressive taxes are applied so that the cost for power use can be reduced, . In addition, since the user can select the operation corresponding to the power unit cost, there is an advantage that power can be supplied at a lower cost and more conveniently in a region having a high progressive tax rate or a generation using a power amount having a high progressive tax rate.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a cogeneration system according to an embodiment of the present invention, and FIG. 2 is a control block diagram of the cogeneration system shown in FIG.

1, the cogeneration system includes a chassis 1 forming an outer appearance, a generator 2 disposed inside the chassis 1, and a generator 2 disposed inside the chassis 1, 2), a heat consumer for receiving heat generated from the drive source, and a heat dissipation unit for dissipating heat generated from the drive source.

The generator (2) is connected to an output shaft of the drive source to produce a rotating electric power of the output shaft. The electric power generated by the generator 2 is directly supplied to a power source such as lighting in a building or a household electric appliance through a power line or stored in a battery 3 installed in the chassis 1, It is supplied to power demand. A power load sensing unit 4 is installed between the generator 2 and the power demanding unit to sense a power load of the power demanding unit.

The driving source may be a fuel cell, an engine 5, or the like. Hereinafter, in the present embodiment, it is assumed that the drive source is the engine 5.

The engine 5 is driven by fossil fuel such as gas or petroleum to drive the generator 2. The engine 5 is provided with a fuel supply pipe 6 through which fuel is supplied to the engine 5, an intake pipe 7 through which air is sucked into the engine 5, And an exhaust pipe 8 through which the gas passes is connected.

The fuel supply pipe (6) is provided with a fuel control solenoid valve (9) for regulating the supply of fuel.

An exhaust gas heat exchanger (10) is installed in the exhaust pipe (8) to recover the exhaust gas heat of the engine (5). In the present embodiment, two exhaust gas heat exchangers 10 are provided.

On the other hand, the engine 5 has various operation modes according to the heat load of the electric power part of the electric power consumer or the heat consumer. That is, an engine load corresponding operation mode in which electric power produced by the generator is supplied to a power consumer or where heat generated from the engine 5 is transferred to a heat consumer, An engine no-load operation mode in which the heat generated by the engine 5 is not supplied to the heat consumer, and an engine stop mode in which the engine 5 is not operated.

The amount of fuel supplied to the engine 5 differs according to the operation mode. In the engine load corresponding operation mode, fuel corresponding to at least one of a power unit and a heat load is supplied. The engine no-load operation mode is supplied with less fuel than in the engine load corresponding operation mode. The engine stop mode is not supplied with fuel to the engine 5.

In order to supply the fuel as described above, the opening degree of the fuel control solenoid valve 9 is determined in accordance with the load in the engine load corresponding operation mode, and in the engine no-load operation mode, do. In the engine stop mode, the fuel control solenoid valve 9 is closed.

The engine 5 is connected to a heat fluid circulation passage 20 for circulating the heat generated in the engine 5.

The heat consumer includes a hot water supply unit 30 that receives the heat generated from the engine 5 and supplies hot water into the building or an air conditioner that cools the interior of the building by receiving heat generated from the engine 5 It is possible. Hereinafter, in the present embodiment, it is assumed that the heat consumer is the hot water supply unit 30.

 The hot water supply unit 30 includes a low temperature bath 31 in which water is stored, a hot water supply channel 32 branched from the heat fluid circulation channel 20, and a hot water heat exchanger And a water circulation flow path 34 connecting the low temperature bath 31 and the hot water heat exchanger 33 to receive heat from the hot water heat exchanger 33.

The low temperature bath 31 is provided with a temperature sensing unit 35 for sensing the temperature inside the low temperature bath 31 and a temperature setting unit 36 for setting the hot water temperature target of the low temperature bath 31 by the user do. The detected temperature sensed by the temperature sensing unit 35 and the preset temperature set in the temperature setting unit 36 are transmitted to the control unit 60, which will be described later. If the detected temperature is less than the lower limit value of the set temperature (for example, 50 DEG C), the control unit 60 determines that there is a hot water supply request. If the detected temperature is equal to or higher than the upper limit value of the set temperature (for example, 60 DEG C), the controller 60 determines that there is no hot water supply request.

The temperature sensing part 35 may be provided inside the low-temperature bath 31 and may be installed at the outlet of the low-temperature bath 31 in the water circulation channel 34.

The water circulation flow path 34 is provided with a water supply pump 37 for circulating water to the low temperature bath 31 and the hot water heat exchanger 33.

The water circulation flow path 34 is provided with a flow rate sensor 38 for sensing the flow rate of water circulating on the water circulation flow path 34. The flow rate sensed by the flow sensor 38 is transmitted to the controller 60, which will be described later. When the flow rate detected by the flow rate sensor 38 is less than the predetermined set flow rate, the flow rate sensor 38 transmits a no flow rate signal to the controller 60. If the sensed flow rate is equal to or greater than the set flow rate, a flow rate signal is transmitted to the controller 60.

The heat dissipation unit 40 includes a heat dissipation path 41 branched from the heat fluid circulation path 20 and a heat dissipation heat exchanger 42 disposed on the heat dissipation path 41. The heat-radiating heat exchanger (42) can cool the heat of the heat fluid by the cooling water such as water in a water-cooling manner, or can co-operate by air. Hereinafter, in the present embodiment, it is assumed that the heat fluid is exchanged with the outside air and the heat of the heat fluid is cooled by air-cooling. A heat-radiating fan 43 for blowing outside air to the heat-radiating heat exchanger 42 is disposed around the heat-radiating heat exchanger 42.

The cogeneration system further includes a switching unit for switching the flow path so that heat generated from the engine 5 is supplied to either the hot water supply unit 30 or the heat dissipation unit 40. The switching portion is a three-way valve (44) provided at a point where the hot-water flow path (32) and the heat-radiating flow path (41) are branched from the heat-fluid circulation path (20).

Meanwhile, the cogeneration system generates heat together with electric power, so that it can be operated when the hot water supply load from the hot water supply unit 30 and the electric power load of the electric power consumer are together, It is possible to operate even if there is only one of them. When there is the power load and there is no hot water supply load, the heat generated from the engine 5 is dissipated through the heat dissipation unit 40.

In the cogeneration system, the generator 2, the external power source 50, and the electric power demanding unit 50 are controlled such that one of the generated power generated by the generator 2 and the commercial power supplied from the external power source is selectively supplied to the power demanded place, (52) for comparing the generated power with each unit price of the commercial power, and for supplying power having a low unit price to the power demanding unit (51); and a system interconnection unit And a controller (60) for controlling the generator (2).

 Generally, the grid connection device 52 is a commercial device that adjusts the voltage, frequency, and phase of power supplied from both sides. Here, the grid connection device 52 adjusts the electric power generated by the generator 2 to correspond to the electric power supplied from the external power source 50 to the electric power demanding device 51. The grid connection device 52 is installed to interconnect the generator 2, the external power source 50 and the power demander 51.

The controller 60 controls the three-way valve 44 and the engine 5 and also controls the grid connection device 52 and the generator 2.

The cogeneration system further includes an input unit for inputting the unit price of the commercial power and the unit price of the energy source supplied to the driving source by the user.

The power unit price corresponding operation selecting unit 53 is disposed so as to be exposed to the outside of the chassis 1. [ The power unit cost corresponding operation selecting unit 53 may be a button or the like which can be selected by pressing the user. The power unit price corresponding operation selecting unit 53 is electrically connected to the controller 60. [ When the user presses the power unit price corresponding operation selecting unit 53, the selection is transmitted to the controller 60 as a signal. When the power unit cost corresponding operation selecting unit 53 is selected, the control unit 60 compares the respective unit prices of the commercial power and the generated power, and controls the operation of the system so that the power of the lower cost unit is supplied. On the other hand, if the power unit cost corresponding operation selecting unit 53 is not selected, the control unit 60 controls the operation of the system to correspond to the power load of the hot water unit.

The input unit may include a commercial power unit price input unit 54 for inputting the unit price of the commercial power and an energy source input unit 55 for periodically inputting the unit price of the energy source supplied to the driving source. . Here, it is assumed that the input section is composed of the commercial power unit price input section 54 and the energy source section is constituted by the input section 55, respectively. The unit price input to the commercial power unit price input unit 54 is the unit price to which the progressive tax is applied.

The control unit 60 may be configured to calculate the unit price of the generated power according to the unit price of the energy source.

However, it is also possible to periodically receive the unit price of the commercial power to which the progressive tax is applied from the KEPCO or the like that supplies the commercial power through the online or the like .

In the present embodiment, the user inputs the unit price of the energy source of the engine 5. However, the unit price of the energy source may be periodically provided through the on- It is also possible.

The control method of the cogeneration system according to the present invention will now be described.

3 is a flowchart showing a control method of the cogeneration system according to the embodiment of the present invention.

Referring to FIG. 3, the user can select the power unit cost corresponding operation mode by pressing the power unit cost corresponding operation selecting unit 53 during initial installation or after installation of the cogeneration system. For example, in a region where progressive taxes are applied, it is advantageous to select and use the power unit cost corresponding operation mode.

The control unit 60 first determines whether the power unit is in a corresponding operation mode (S1)

If the power unit price is not in the corresponding operation mode, the controller 60 operates the system in response to the hot water supply unit or the power load. That is, when a hot water supply load is requested in the hot water supply unit 30, the engine 5 is operated to generate heat corresponding to the hot water supply load. Alternatively, if there is a power load from the power demanding unit 51, the engine 5 may be operated to generate power corresponding to the power load.

On the other hand, if the power unit is in the corresponding operation mode, the controller 60 determines whether there is a hot water supply load. (S2)

The control unit 60 interrupts the supply of the external power source 50 and drives the generator 2 by a power load and if it is determined that there is the hot water supply load, (S4) That is, when there is the hot-water supply load, the engine 5 and the generator 2 must be driven to cope with the hot-water supply load. Accordingly, when there is the hot-water supply load, the generator 2 supplies the generated power to the power consumer 51. The controller 60 is connected to the generator 2 via the grid- So that the electric power demand site 51 is electrically connected.

On the other hand, if it is determined that there is no hot-water supply load, the controller 60 compares the unit price of the generated power with the unit price of the commercial power. (S5) Here, the unit price of the commercial power is a unit price to which the progressive tax is applied. The unit price of the generated power is calculated by the controller 60 in consideration of the unit price of the energy source. The unit price of the commercial power is the unit price input by the user. For example, the user can input the unit price of the commercial power at the beginning of each month.

If the unit price of the generated power is lower than the unit price of the commercial power, the controller 60 cuts off the supply of the external power source 50. The control unit 60 drives the generator 2 by the power load and supplies the generated power generated by the generator 2 to the power consumer 51. (S4) So that the generator 2 and the electric power consumer 51 are connected to each other.

On the other hand, if the unit price of the generated power is higher than the unit price of the commercial power, the controller 60 stops the generator 2 and the engine 5. The control unit 60 receives the commercial power from the external power source 50 and the power consumption source 51 via the grid connection unit 52. That is, Make it electrically connected.

On the other hand, progressive taxes depend on the amount of electricity used. That is, when the power consumption exceeds the predetermined set amount, the progressive tax is applied from the excess amount.

Therefore, even when the commercial power is used, the unit price of the generated power is continuously compared with the unit price of the commercial power, and the low power is supplied.

1 is a schematic block diagram of a cogeneration system according to an embodiment of the present invention.

2 is a control block diagram of the cogeneration system shown in FIG.

3 is a flowchart showing a control method of the cogeneration system according to the embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

2: generator 5: engine

52: grid connection device 53: power unit cost corresponding operation selection unit

54: commercial power unit price input unit 55: energy source price input unit

60:

Claims (11)

generator; A driving source for driving the generator and generating heat; A hot water supply unit for supplying hot water heated by the heat generated from the driving source; A power unit price corresponding operation selecting unit for selecting and setting the power unit cost corresponding operation mode; A grid linking unit for linking the generator, the external power source and the power demand site so that one of the generated power generated by the generator and the commercial power supplied from the external power source is selectively supplied to the power demand site; And And a control unit for controlling each of the grid interconnecting device and the generator so that the power demand is supplied to the power demanding place by comparing the respective power prices of the generated power and the commercial power when the power cost corresponding operation mode is selected and set and, Wherein, When the sensed temperature of the hot water supplied from the hot water supply unit is lower than the predetermined set temperature, it is determined that there is a hot water supply request, and the grid connection device is controlled so as to supply the generated power, Cogeneration system. delete The method according to claim 1, Wherein the control unit compares the unit price of the generated power with the unit price of the commercial power to which the progressive tax is applied. The method according to claim 1, And an input unit for inputting the unit price of the commercial power. The method according to claim 1, And an input unit for inputting a unit price of an energy source supplied to the driving source, Wherein the control unit calculates the unit price of the generated power according to the unit price of the energy source. delete Selecting and setting a power unit price corresponding operation mode; Determining whether there is a hot water supply request based on the sensed temperature and the set temperature set for the hot water supplied from the hot water supply unit when the power unit is set to the corresponding operation mode; Comparing the unit price of the generated power generated by the generator with the unit price of the commercial power supplied from the external power supply when it is determined that there is no hot water supply load; And And a supply step of driving the generator by a power load and supplying the generated power to the power consumer when the unit price of the generated power is lower than the unit price of the commercial power, The hot water- Determines that there is a hot water supply request if the detected temperature is lower than the set temperature, and determines that there is no hot water supply request if the detected temperature is higher than the set temperature, Further comprising the step of supplying the generated power generated by the generator to the power demanding entity when it is determined that there is a hot water supply request in the hot water supply determining step. delete The method of claim 7, Wherein the supplying step comprises: And supplies the commercial power to the power consumer if the unit price of the generated power is higher than the unit price of the commercial power. The method of claim 7, Wherein the comparing step compares the unit price of the generated power with the unit price of the commercial power to which the progressive tax is applied. delete

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