KR20070009872A - Electric generation air condition system and the control method for the same - Google Patents

Abstract

A cogeneration system and a method for controlling the same are provided to improve the operation efficiency of the system by outputting one of the power generated by the cogeneration system and general power to an air conditioner. A cogeneration system includes a generator(50), a drive source(52), a wasted heat recovering unit(60), a power switching unit(51), a power consuming device, and a control unit. The drive source drives the generator. The wasted heat recovering unit recovers the wasted heat of the drive source. The power switching unit switches one of the power generated by the generator and the general power to be output. The power consuming device receives the power output through the power switching unit. When the power consuming device is operated, if the load of the power consuming device exceeds a power switching border according to the load of the power consuming device, the control unit controls the power switching unit so that the power can be switched.

Description

Cogeneration system and control method {Electric generation air condition system and the Control method for the Same}

1 is a configuration diagram of a cogeneration system according to the prior art,

2 is a configuration diagram when the cogeneration system according to the present invention is a power generation output, the air conditioner is in the cooling operation mode,

3 is a configuration diagram when the cogeneration system according to the present invention is a power generation output, the air conditioner is the outdoor high temperature heating operation mode,

4 is a configuration diagram when the cogeneration system according to the present invention is a power generation output, the air conditioner is the outdoor low temperature heating operation mode,

5 is a configuration when the cogeneration system according to the present invention is a commercial power output, the air conditioner in the cooling operation mode,

6 is a commercial power output of the cogeneration system according to the present invention, the configuration when the air conditioner in the heating operation mode,

7 is a flow chart according to the control method of the cogeneration system according to the present invention,

8 is a flow chart when switching from the generated power to the commercial power of the cogeneration system according to the present invention,

9 is a flow chart when switching from commercial power to power generation of the cogeneration system according to the present invention,

10 is a graph showing a power switching boundary in the cooling operation mode of the cogeneration system according to the present invention;

11 is a graph showing a power saving system in the heating operation mode of the cogeneration system according to the present invention;

12 is a graph showing the operating cost in the cooling operation mode of the cogeneration system according to the present invention,

13 is a graph showing the operating costs in the heating operation mode of the cogeneration system according to the present invention.

<Explanation of symbols on main parts of the drawings>

50: generator 51: power switching device

52: drive source 55: engine cooling device

60: waste heat recovery device 70: compressor

73: four-way valve 74: indoor heat exchanger

75: outdoor heat exchanger 76: indoor expansion valve

77: outdoor expansion valve 80: waste heat supply heat exchanger

85: waste heat radiator 94: three-way

100: first damper 104: second damper

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system and a control method thereof, and more particularly, to a cogeneration system and a method of controlling the cogeneration system in which a hysteresis region is set in order to minimize the number of times of power switching during generation of power generation and commercial power.

Cogeneration systems, commonly referred to as cogeneration systems, are systems that produce power and heat simultaneously from a single energy source.

The cogeneration system can recover waste heat of exhaust gas or cooling water generated by power generation by driving a gas engine or turbine, and can increase the overall thermal efficiency by 70-80%. In particular, it is a high-efficiency energy utilization method that utilizes the waste heat recovered in particular for heating, cooling, and hot water supply.

1 is a block diagram of a cogeneration system according to the prior art.

In the conventional cogeneration system, as shown in FIG. 1, a generator 2 for generating electric power and a driving source 10 such as a gas engine for driving heat of the generator 2 and generating heat, hereinafter referred to as a 'gas engine' ), A waste heat recovery apparatus 20 for recovering waste heat generated by the gas engine 10, and a heat demand unit 30 for utilizing waste heat of the waste heat recovery apparatus 20 for hot water supply or the like to radiate heat to the outside. It is configured to include).

The generated electric power generated by the generator 2 is supplied to a power consuming device such as various lighting fixtures or an air conditioner 4 in the home.

The generator 2 and the gas engine 10 are installed in an engine room E of a chassis (not shown) formed separately from the heat demand 30.

The air conditioner 4 includes an indoor unit 3 and an outdoor unit 5.

The waste heat recovery apparatus 20 includes an exhaust gas heat exchanger 22 which takes heat of exhaust gas discharged from the gas engine 10, and a cooling water heat exchanger that takes heat of cooling water cooling the gas engine 10 ( 24).

The exhaust gas heat exchanger 22 is connected to the heat demand 30 and the first heat supply line 23, and the waste heat taken from the exhaust gas of the gas engine 10 is the first heat supply line 23. It is transmitted to the heat demand 30 through.

The cooling water heat exchanger 24 is connected to the heat demand 30 and the second heat supply line 25, and the heat taken away from the cooling water rotor cooling the gas engine 10 is the second heat supply line 25. It is transmitted to the heat demand 30 through.

However, in the cogeneration system according to the related art, when the load of the air conditioner 4 is small, the amount of power generated by the gas engine 10 is reduced, so that the amount of power generated by the gas engine 10 is reduced, so that the gas engine 10 is reduced. Since the power generation efficiency, which is the power generation amount of the gas engine 10 with respect to the gas input amount, is lowered, the operating efficiency of the system is lowered, and the operating cost is relatively high compared to the operating efficiency of the system.

In general, when the load of the air conditioner 4 is maximum, the power generation efficiency of the gas engine 10 is about 25% to 30%, and when the load of the air conditioner 4 is minimum, the gas engine ( The power generation efficiency of 10) is 10% or less, and the power generation efficiency of the gas engine 10 is reduced by about 40% according to the load of the air conditioner 4.

The present invention has been made to solve the above-mentioned problems of the prior art, if the load of the air conditioner is large supply the generated power generated by the generator to the air conditioner, if the load of the air conditioner is the air conditioning The purpose of the present invention is to provide a cogeneration system and a control method thereof that can maximize the operating efficiency of the system and reduce its operating cost by supplying commercial power produced by the electric company.

In addition, the present invention is a cogeneration system in which a hysteresis region in which a power generation area and a commercial power area overlap is set so as to minimize the number of power switching when switching to either electric power or commercial power during operation of an air conditioner. And another object is to provide a control method thereof.

Another object of the present invention is to provide a cogeneration system and a control method thereof in which waste heat of a driving source for driving a generator is utilized to increase the heating performance of the air conditioner in the heating operation mode of the air conditioner and maximize its efficiency. There is this.

Cogeneration system according to the present invention for solving the above problems is a generator; A drive source for driving the generator; A waste heat recovery apparatus for recovering waste heat of the driving source; A power switching device for switching electric power such that any one of generated power and commercial power produced by the generator is output; A power consuming device supplied with the power output through the power switching device; And a controller configured to control the power switching device to switch power when the load of the power consumption device exceeds a power switching boundary according to the load of the power consumption device more than a predetermined time while the power consumption device is in operation. It features.

The power consuming device is an air conditioner including an indoor unit and an outdoor unit, and the control unit is configured according to an operation mode of the air conditioner together with an operation ratio of the indoor unit which is a load of the power consuming device and an outdoor temperature in which the outdoor unit is installed. It is characterized by controlling the power switching device.

The power consumer is an air conditioner consisting of an indoor unit and an outdoor unit; The power switching boundary is determined according to an operating ratio of an indoor unit and an outdoor temperature according to an operation mode of the air conditioner; The air conditioner is in a cooling operation mode, and when the power generation power is output, when the operation ratio of the indoor unit is smaller than the first boundary ratio by a predetermined ratio or more, and the outdoor temperature is smaller than the first boundary temperature by a predetermined temperature or more, the air conditioner is switched to commercial power; The air conditioner is in a cooling operation mode, and when the commercial power is output, when the operation ratio of the indoor unit is larger than the second boundary ratio by a predetermined ratio or more, or when the outdoor temperature is larger than the second boundary temperature by a predetermined temperature or more, it is switched to generated power; When the air conditioner is in a heating operation mode, and the operation ratio of the indoor unit at the time of generating power is smaller than the third boundary ratio by a predetermined ratio or more, and the outdoor temperature is larger than the third boundary temperature by a predetermined temperature or more, it is switched to commercial power; The air conditioner is a heating operation mode, when the commercial power output when the operation ratio of the indoor unit is larger than the fourth boundary ratio by a predetermined ratio or more, or when the outdoor temperature is larger than the fourth boundary temperature by a predetermined temperature or more, it is switched to the generation power. It is done.

The power consuming device is an air conditioner comprising an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and an indoor unit including an indoor expansion valve and an indoor heat exchanger, and the air conditioner is returned to the waste heat recovery device. Waste heat is selectively supplied through a waste heat supply heat exchanger.

The air conditioner is operated in a cooling cycle in which the refrigerant compressed by the compressor passes through the four-way valve, the outdoor heat exchanger, the indoor expansion valve, the indoor heat exchanger, and the four-way valve in order in the cooling operation mode.

When the air conditioner is a heating operation mode and does not use the waste heat of the driving source, the refrigerant compressed in the compressor passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, the outdoor heat exchanger, and the four-way valve in order. It is characterized in that it is operated by an outdoor high temperature heating cycle circulated to.

The air conditioner is a heating operation mode, and when the waste heat of the driving source is used, the refrigerant compressed in the compressor passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, the waste heat supply heat exchanger, and the four-way valve, and then circulates to the compressor. The outdoor low temperature heating cycle is characterized in that the operation.

In addition, in the control method of the cogeneration system according to the present invention for achieving the above object, it is determined whether the load of the power consumer device exceeds the power switching boundary according to the load of the power consumer device more than a predetermined time when the power consumer operates. A power switching determining step; When the power switching is determined, it is characterized in that it comprises a power switching step for outputting power other than the power selected from the generated power and commercial power to the power consumer.

The power consuming device is an air conditioner including an indoor unit and an outdoor unit, and the power switching boundary is set according to an operation ratio of the indoor unit according to an operation mode of the air conditioner and an outdoor temperature, and the power switching determining step includes: When the air conditioner is in the cooling operation mode, and the operation ratio of the indoor unit at the generation power output is smaller than the first boundary ratio by a predetermined ratio or more, and the outdoor temperature is smaller than the first boundary temperature by a predetermined temperature or more, switching to commercial power is determined; When the air conditioner is in a cooling operation mode and the commercial power is output, when the operation ratio of the indoor unit is larger than the second boundary ratio by a predetermined ratio or more, or when the outdoor temperature is larger than the second boundary temperature by a predetermined temperature or more, switching to generation power is determined; When the air conditioner is in a heating operation mode, and the operation ratio of the indoor unit at the time of generating power is smaller than the third boundary ratio by a predetermined ratio or more, and the outdoor temperature is larger than the third boundary temperature by a predetermined temperature or more, determining to switch to commercial power; When the air conditioner is in the heating operation mode and the commercial power is output, when the operation ratio of the indoor unit is greater than or equal to the fourth boundary ratio by more than a predetermined ratio or when the outdoor temperature is greater than or equal to the fourth boundary temperature by more than the predetermined temperature, it is determined to switch to generated power. It features.

The power switching step, characterized in that for switching the power after the power consumer pauses.

The power switching step is characterized in that the power is switched when a predetermined time elapses after the power is selected.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 13.

In the cogeneration system according to the present invention, a power switching device for switching the power so that any one of the generator 50 for generating power generation, and the generated power and commercial power (50 ') produced in the generator 50 is output. (51), a drive source (52) for driving the generator (50), a waste heat recovery device (60) for recovering waste heat of the drive source (52), and generated power or commercial power produced by the generator (50). And a controller (M) for controlling the electric power switching device (51) according to the load of the air conditioner.

The generator 50 is any one of an alternator and a direct current generator, the rotor is connected to the output shaft of the drive source 60 to produce power when the output shaft rotates.

The power switching device 51 is a power generation switchgear (GCB) 51a that regulates the generated power output of the generator 50, and a commercial power switchgear (MCB) 51b that controls the output of the commercial power 50 '. It is composed of

The driving source 52 may be implemented as a fuel cell or various devices such as an engine and a turbine that are operated by using a fuel such as gas or oil. ).

The engine 52 includes a fuel supply passage 53 through which fuel is supplied to a combustion chamber provided therein, and a waste heat recovery passage 54 through which exhaust gas is exhausted from the combustion chamber.

In addition, the engine 52 may be easily broken when the engine 52 is overheated, its life may be shortened, and the output of the engine may be reduced, and the reliability of the engine 52 may be degraded. The engine cooler 55 is provided to allow the engine 52 to operate within an appropriate temperature range.

The engine cooler 55 includes a coolant circulation flow path 56 for guiding the coolant to circulate between the engine 52 and the coolant heat exchanger 61, which will be described later, among the waste heat recovery device 60, and the coolant circulation flow path. And a coolant pump 57 installed on the pump 56 to pump the coolant.

The waste heat recovery device 60 is connected to the cooling water circulation passage 56 to extract the heat of the cooling water that has become a high temperature after cooling the engine 52 and the waste heat recovery of the engine 52. The first and second exhaust gas heat exchangers 62 and 63 may be connected to the passage 54 to recover the heat of the exhaust gas exhausted from the engine 52.

In particular, the waste heat recovery device 60 may be provided to selectively recover the waste gas waste heat of the engine 52 according to the operation mode of the air conditioner.

That is, the exhaust gas heat exchanger 62 is provided on the waste heat recovery passage 54 to recover the waste gas waste heat of the engine 52, and the exhaust gas heat exchanger 62 is disposed on the waste heat recovery passage 54. The first damper 100 for opening and closing the waste heat recovery passage 54 is provided at the inlet side.

In addition, in the waste heat recovery passage 54, the waste heat discharge passage 102 allows exhaust gas waste heat of the engine 52 to be directly discharged to the outside by bypassing the first and second exhaust gas heat exchangers 62 and 63. ) Is connected.

The waste heat discharge passage 102 is preferably connected to the waste heat recovery passage 54 between the first exhaust gas heat exchanger 62 and the first damper 100.

The waste heat discharge passage 102 is provided with a second damper 104 for opening and closing the waste heat discharge passage 102.

The first and second dampers 100 and 104 provided as described above are operated in the open mode or the closed mode according to the power output through the power switching device 51 and the operation mode of the air conditioner, respectively.

The waste heat recovered by the waste heat recovery device 60 may be supplied to some of the power consumer devices through the waste heat supply heat exchanger 80 or may be radiated in the air through the waste heat radiator 85.

The waste heat supply heat exchanger (80) absorbs the heat recovered in at least one of the cooling water heat exchanger (61) and the first and second exhaust gas heat exchangers (62, 63), and the cooling water heat exchanger (61). And first and second exhaust gas heat exchangers 62 and 63 and a heat medium circulation passage 64 for guiding the heat medium for waste heat recovery. That is, the heat medium circulation passage 64 is a heat medium in the heat medium circulation passage 64 is the cooling water heat exchanger 61, the second exhaust gas heat exchanger 63, the first exhaust gas heat exchanger 62, and Waste heat supply heat exchanger 80 may be provided to circulate in turn.

The heat medium circulation passage 64 is provided with a heat medium circulation pump 65 that performs a pumping function to circulate the heat medium in the heat medium circulation passage 64.

In addition, the heat medium circulation passage 64 is connected to an expansion tank 66 in which gas generated on the heat medium circulation passage 64 is stored at an inlet side of the heat medium circulation pump 65.

The waste heat radiator 85 includes a heat radiating heat exchanger 86 in which heat recovered from the cooling water heat exchanger 61 and the first and second exhaust gas heat exchangers 62 and 63 is radiated to the atmosphere, and the heat medium circulates. The heat dissipation path 87 is connected to the flow path 64 to guide the heat medium in the heat medium circulation path 64 to the heat dissipation heat exchanger 68. In addition, the waste heat radiating device 85 includes a waste heat radiating blower 88 for forcibly blowing outside air to the heat radiating heat exchanger 86 in order to maximize heat radiation.

The three-way side 94 for switching the flow of the heat medium is installed at any one of the two points of the junction where the waste heat radiation passage 87 and the heat medium circulation passage 64 are interconnected.

The air conditioner includes a compressor (70), a four-way valve (73), an outdoor heat exchanger (75), an outdoor expansion valve (77), an outdoor unit (Oa) equipped with an outdoor temperature sensor (72), and the indoor heat. The exchanger 74 and the indoor unit Ia provided with the indoor expansion valve 76 are provided.

The compressor 70 may be composed of one or more than two plural to each outdoor unit Oa. Hereinafter, only two compressors 70 are configured for each outdoor unit Oa.

The two compressors 70 installed in the respective outdoor units Oa are connected through a common accumulator 78 installed at a suction side on which a refrigerant, which is a heat medium of the air conditioner, is sucked.

The air conditioner provided as described above may be constituted by one outdoor unit Oa and one indoor unit Ia, or may be constituted by one outdoor unit Oa and a plurality of indoor units Ia. It is also possible to be composed of three outdoor units Oa and a plurality of indoor units Ia. Hereinafter, the air conditioner according to the present embodiment will be described as being limited to a plurality of outdoor units Oa and a plurality of indoor units Ia.

The plurality of outdoor units Oa may receive power output through the power switching device 51, and the plurality of indoor units Ia may receive commercial power connected separately.

The plurality of outdoor units Oa may have different capacities, and the plurality of indoor units Ia may also have different capacities.

On the other hand, the plurality of outdoor unit (Oa) and the indoor unit (Ia), and the waste heat supply heat exchanger 80 for supplying the waste heat of the engine 52 to the air conditioner during the heating operation is the cooling / heating of the air conditioner It is connected through a refrigerant circulation passage 79 for guiding the refrigerant, which is a heat medium for circulation.

The refrigerant circulation passage 79 is provided with a first opening / closing valve 81 at an inlet side of the waste heat supply heat exchanger 80 so that refrigerant may flow into or shut off the waste heat supply heat exchanger 80.

In addition, the refrigerant circulation passage 79 includes a first check valve 91 at the outlet side of the waste heat supply heat exchanger 80 to block the refrigerant from flowing back to the waste heat supply heat exchanger 80.

In addition, a waste heat supply heat exchanger bypass connecting the inlet side and the outlet side of the waste heat supply heat exchanger 80 to allow the refrigerant to bypass the waste heat supply heat exchanger 80 in the refrigerant circulation passage 79. The flow path 95 is provided.

The waste heat supply heat exchanger bypass passage 95 is provided with a second check valve 92 such that refrigerant flows only from the outlet side of the waste heat supply heat exchanger 80 to the inlet side of the waste heat supply heat exchanger 80. .

In addition, the refrigerant circulation passage 79 includes a second opening / closing valve 82 at one side of the outdoor heat exchanger 75 so that the refrigerant may be introduced into or blocked by the outdoor heat exchanger 75.

In addition, the refrigerant circulation passage 79 includes a third check valve 93 at the other side of the outdoor heat exchanger 75 to block the refrigerant from flowing back from the indoor unit Ia to the outdoor heat exchanger 75. do.

In addition, the refrigerant circulation passage 79 is provided with an outdoor heat exchanger bypass passage 90 connecting one side and the other side of the outdoor heat exchanger 75 so that the refrigerant bypasses the outdoor heat exchanger 75. .

At the inlet side of the outdoor heat exchanger bypass flow path 90, the outdoor expansion valve 77 is provided.

At the outlet side of the outdoor heat exchanger bypass flow path 90, a third open / close valve 83 capable of opening and closing the outdoor heat exchanger bypass flow path 90 is provided.

The outdoor heat exchanger bypass flow path 90 may be connected to the other side of the outdoor heat exchanger 75 through an outdoor heat exchanger connection flow path 96.

The outdoor heat exchanger connection flow path 96 is provided with a fourth open / close valve 84 for opening and closing the outdoor heat exchanger connection flow path 96.

The operation mode of the air conditioner configured as described above includes a cooling operation mode in which the indoor unit Ia supplies cold air, and a heating operation mode in which the indoor unit Ia supplies warm air.

The heating operation mode of the air conditioner is an outdoor high temperature heating operation mode in which the waste heat of the engine 52 is not used through the waste heat supply heat exchanger 80 according to the outdoor temperature at which the outdoor unit Oa is installed. And, through the waste heat supply heat exchanger 80 may be divided into the outdoor low temperature heating operation mode using the waste heat of the engine (52).

On the other hand, the cogeneration system may be divided into the air conditioner and the cogeneration unit for driving the air conditioner.

The cogeneration unit includes a main unit 110 including the generator 50, the engine 52, the engine cooling device 55, and a waste heat recovery device 60, the waste heat supply heat exchanger 80, and waste heat. The heat sink 85 may be divided into the sub unit 120 installed.

The main unit 110 is provided with a main unit controller 112 and a ventilation blower 114 for ventilation of the main unit 110.

The sub unit 120 includes a sub unit controller 122 connected to the main unit controller 112.

The control method of the cogeneration system according to the present invention configured as described above, in particular with reference to FIG. 7, is as follows.

When the operation request signal of the air conditioner is input in the state in which the engine 52 and the air conditioner are stopped (S2), according to the operation mode of the air conditioner for the operation of the air conditioner, the first The third check valves 91 to 93, the three-way valve 94, the first to fourth open / close valves 81 to 84, and the first and second dampers 100 and 104 are set (S4). .

The first to third check valves 91 to 93, the three-way valve 94, the first to fourth open / close valves 81 to 84, and the first and second dampers 100 and 104 are Since the selected power is set before outputting through the power switching device 51, it is preferable to receive commercial power connected separately.

When the setting step according to the operation mode of the air conditioner is finished, any one of the generated power and the commercial power 50 'of the generator 50 is output to the air conditioner through the power switching device 51 (S6). ).

At this time, the power switching device 51 is controlled according to the operation mode of the air conditioner and the load of the air conditioner, or the generated power of the generator 50 preset for the initial operation of the air conditioner Alternatively, commercial power 50 'may be output.

Here, the load of the air conditioner includes an operating ratio (%) of the indoor unit Ia, an outdoor temperature where the outdoor unit Oa is installed through the outdoor temperature sensor 72, and an indoor unit where the indoor unit Ia is installed. Temperature or the like.

The driving ratio (%) of the indoor unit (Ia) is the sum of the capacity of the indoor unit (Ia) that has requested driving with respect to the total capacities of the plurality of indoor units (Ia).

As described above, when any one of the generated electric power and the commercial power 50 'of the generator 50 is output to the air conditioner through the power switch 51, the air conditioner through the power switch 51 It is operated by receiving the output power to perform a cooling / heating function and the like (S8).

On the other hand, the load condition of the air conditioner can be changed while the air conditioner is operating, the power output to the air conditioner is switched according to a power switching algorithm to be described later.

Then, when the operation of the air conditioner is finished (S10), the output of the generated power and commercial power (50 ') of the generator 50 is all cut off (S12). In addition, if the engine 52 is being driven, the engine 52 is stopped.

The power switching method by the power switching algorithm will be described in detail with reference to FIGS. 8 and 9 as follows.

 First, as shown in FIG. 8, when the air conditioner is operated by receiving the generated power of the generator 50, the generated power switch 51a of the power switching device 51 is in an on state. The commercial power switch 51b is in an off state, and the engine 52 is in operation (S20).

In the above operation state, first, a power switching determination step of determining whether the load of the air conditioner satisfies the power switching condition to the commercial power 50 'is performed (S22).

The power switching condition is whether or not the load of the air conditioner has exceeded a power switching boundary according to the load of the air conditioner by more than a predetermined value.

When the power switching condition is satisfied, after the pause request signal of the outdoor unit Oa is input, the outdoor unit Oa of the air conditioner, that is, the compressor 70, is temporarily stopped (S24). That is, the air conditioner is paused.

When the outdoor unit Oa is paused, the generated power switch 51a is set in an off state from an on state (S26). That is, both the power generation switch 51a and the commercial power switch 51b are in an off state, and there is no power output to the air conditioner.

When all of the generated power switch 51a and the commercial power switch 51b have elapsed in the off state for a predetermined time (for example, 3 minutes) (S28), the generated power switch 51a is kept in the off state. The commercial power switch 51b is set to the on state, and the commercial power 50 'is output to the air conditioner (S30).

After the commercial power 50 'is outputted to the air conditioner, the pause cancel signal is input to the outdoor unit Oa, and the outdoor unit Oa is re-operated (S32). That is, the air conditioner is restarted.

On the other hand, in particular referring to Figure 9, the engine 52 is in a stopped state, the power generation switch 51a is in the off state, the commercial power switch 51b is set to the on state, the air conditioner is commercially available When the power is supplied and operated (S40), a power switching determination step of determining whether the load of the air conditioner satisfies the power switching condition to the generated power of the generator 50 is performed (S42).

When the power switching condition is satisfied in the above, after the pause request signal of the outdoor unit Oa is input, the outdoor unit Oa is paused (S44), and the commercial power switch 51b is set to the off state. (S46).

When the power generation switch 51a and the commercial power switch 51b are both turned off, a predetermined time (for example, 3 minutes) elapses (S48), the engine 52 and the generator 50 are operated. The generated power switch 51a is set in an on state, and the generated power of the generator 50 is output to the air conditioner (S50).

Then, after the pause cancel signal is input to the outdoor unit Oa, the outdoor unit Oa is re-operated (S52).

The power switching algorithm as described above is preferably repeated so that the power can be switched every predetermined time while the air conditioner is operating.

At this time, if the power holding time is too short, the operation and pause of the air conditioner is frequently repeated due to frequent power switching, thereby lowering cooling / heating performance and reliability of the air conditioner, as well as cogeneration. Overloading the power generation system can shorten its lifespan.

On the other hand, if the power holding time is too long, it is difficult to actively cope with the change in the operating condition of the air conditioner, and eventually, it is difficult to maximize the operating efficiency of the cogeneration system by switching power according to the operating condition of the air conditioner.

The power switching boundary may be set according to an operating ratio (%) of the indoor unit Ia, which is a load determining factor of the air conditioner, and an outdoor temperature at which the outdoor unit Oa is installed through the outdoor temperature sensor 72. Can be.

The power switching determination based on the power switching condition based on the power switching boundary will be described below with reference to FIGS. 10 and 11.

As shown in FIG. 10, when the air conditioner is in a cooling operation mode and the power generation power output state of the generator 50 is in operation, an operation ratio of the indoor unit Ia is a predetermined ratio ΔIc than the first boundary ratio I1. ), And when the outdoor temperature is smaller than the first boundary temperature T1 by the predetermined temperature (DELTA) Tc or more, switching to the commercial power 50 'is determined.

As shown in FIG. 10, when the air conditioner is in the cooling operation mode and the commercial power 50 ′ is output, the operation ratio of the indoor unit Ia is greater than or equal to the second boundary ratio I2 by a predetermined ratio ΔIc. When the temperature increases, or when the outdoor temperature becomes larger than the second boundary temperature T2 by a predetermined temperature ΔIc or more, it is determined to switch to the generated power of the generator 50.

As shown in FIG. 11, when the air conditioner is in the heating operation mode and the power generation power output state of the generator 50 is set, the operation ratio of the indoor unit Ia is a predetermined ratio than the third boundary ratio I3. It becomes smaller than (DELTA) Ih and becomes larger than predetermined temperature (DELTA) Th more than 3rd boundary temperature (T3), and it switches to the commercial power 50 '.

As illustrated in FIG. 11, when the air conditioner is in the heating operation mode and the commercial power 50 ′ is output, the operation ratio of the indoor unit Ia is greater than or equal to the fourth boundary ratio I4 by a predetermined ratio ΔIh. When the temperature increases, or when the outdoor temperature becomes larger than the fourth boundary temperature T4 by a predetermined temperature ΔTh or more, it is determined to switch to the generated power of the generator 50.

Here, the region in which the generated power and the commercial power output region of the generator 50 overlap may be referred to as a hysteresis region H1 and H2.

As described above, when the power switching device 51 is controlled according to whether or not the power switching condition is satisfied while the air conditioner is operated, it is possible to prevent the operating efficiency of the engine 52 from being lowered, as shown in FIGS. 12 and 13. As such, running costs can be minimized.

That is, FIG. 12 is a graph showing a result of subtracting an operating cost of using generated power from an operating cost of using commercial power in a cooling operation mode, wherein the operating ratio of the indoor unit Ia is 0 and the outdoor temperature is 21 degrees Celsius. When (a) is the use of commercial power is advantageous, when the operation ratio of the indoor unit (Ia) is 100 and the outdoor temperature is 43 degrees (b) it can be seen that the generation power is more advantageous.

FIG. 13 is a graph showing the result of subtracting the operating cost of using generated power from the operating cost of using commercial power in the heating operation mode. When the operating ratio of the indoor unit Ia is 100 and the outdoor temperature is minus 7 degrees Celsius. (c) shows that the generated power is advantageous, and when the indoor unit operation ratio is 0 and the outdoor temperature is 24 ° C. (d), the commercial power is advantageous.

On the other hand, the operation of the cogeneration system configured and operated as described above will be described according to the operation mode and power of the air conditioner.

First, the operation mode of the air conditioner is a cooling operation mode, and when the generation power output is described with reference to FIG.

When the generator 50 is generated by the driving force of the engine 52, the engine 52 is operated at an appropriate temperature by the engine cooling device 55. That is, as the coolant on the coolant circulation passage 56 is pumped by the coolant pump 57, the heat of the engine 52 is absorbed by the coolant, and the coolant that absorbs the heat of the engine 52 is After the heat is released from the coolant heat exchanger (61), it is circulated back to the engine (52).

The coolant waste heat recovered by the coolant heat exchanger 61 is pumped into the heat medium circulation pump 65 as the heat medium on the heat medium circulation path 64 is pumped to the coolant heat exchanger 61 and the second exhaust gas heat exchanger. And after passing through the first exhaust gas heat exchanger 63, the waste heat radiator 85 is transferred through the three-way side 94.

The coolant waste heat transferred to the waste heat radiator 85 is radiated to the outside by the waste heat radiator 85.

Part of the exhaust gas waste heat of the engine 52 is immediately discharged to the outside through the waste heat discharge passage 102, and the rest is recovered through the second exhaust gas heat exchanger 63, and together with the cooling water waste heat. The heat is radiated from the waste heat radiator 85.

In the air conditioner, the refrigerant compressed by the compressor 70 includes a four-way valve 73, an outdoor heat exchanger 75, an indoor expansion valve 76, an indoor heat exchanger 74, and a four-way valve 73. After passing through) is circulated to the compressor (70).

Then, the refrigerant in the refrigerant circulation passage 79 is compressed by the compressor 70, is condensed by heat exchange with outdoor air in the outdoor heat exchanger 75, and is expanded by the indoor expansion valve 76. The indoor heat exchanger 74 exchanges heat with the indoor air and evaporates, whereby the indoor unit Ia supplies cold air.

Next, the operation mode of the air conditioner is the outdoor high temperature heating operation mode, and when described with reference to FIG.

 The engine 52 is operated at an appropriate temperature by the engine cooling device 55, and the generator 50 generates power generated by the driving force of the engine 52.

After the waste water waste heat and part of the waste gas waste heat of the engine 52 are recovered by the waste heat recovery device 60, the waste heat heat dissipation device 85 is radiated, and the waste gas waste heat of the engine 52 is exhausted. A part is discharged directly through the waste heat discharge passageway 102.

In the air conditioner, the refrigerant compressed by the compressor (70) is the four-way valve 73, the indoor heat exchanger (74), the indoor expansion valve (76), the outdoor expansion valve (77), the outdoor heat exchanger (75), After passing through the waste heat supply heat exchanger (80), and the four-way valve (73), it is circulated to the compressor (70). At this time, the outdoor expansion valve 77 is controlled according to the degree of superheat.

Here, since the waste heat recovered by the waste heat recovery device 60 is not transmitted to the waste heat supply heat exchanger 80, the refrigerant passes through the waste heat supply heat exchanger 80 due to the design characteristics of the refrigerant circulation flow path 79. However, it is not evaporated in the waste heat supply heat exchanger (80).

Then, the refrigerant in the refrigerant circulation passage 79 is evaporated in the outdoor heat exchanger 75 as opposed to in the cooling operation mode, and heat is condensed by dissipating heat into the indoor air in the indoor heat exchanger 74, whereby the indoor unit ( Ia) supplies warm air.

Next, the air conditioner is the outdoor low-temperature heating operation mode, and when described with reference to Figure 4 when generating power output.

The engine 52 is operated at an appropriate temperature by the engine cooling device 55, and the generator 50 generates power generated by the driving force of the engine 52.

The waste water waste heat of the engine 52 and the waste gas waste heat of the engine 52 are sequentially recovered through the waste heat recovery device 60. At least a part of the waste heat recovered by the waste heat recovery device 60 is transferred to the waste heat supply heat exchanger 80, and the surplus waste heat remaining after being transferred to the waste heat supply heat exchanger 80 passes through the waste heat radiator 85. Heat dissipation through.

In the air conditioner, the refrigerant compressed by the compressor (70) is a four-way valve (73), an indoor heat exchanger (74), an indoor expansion valve (76), an outdoor expansion valve (77), a waste heat supply heat exchanger (80). Then, after passing through the four-way valve 73 in turn circulated to the compressor (70). At this time, the outdoor expansion valve 77 is controlled according to the degree of superheat.

Then, the refrigerant in the refrigerant circulation passage 79 is evaporated in the waste heat supply heat exchanger 80, and condensed by dissipating heat into the indoor air in the indoor heat exchanger 74, whereby the indoor unit Ia is warm air. Will be supplied.

In the outdoor low temperature heating operation mode as described above, since the waste heat supply heat exchanger 80 instead of the outdoor heat exchanger 75 serves as an evaporator, it is possible to always provide a constant heating capacity regardless of the outdoor temperature change. The compressor 70 can be operated without difficulty.

In addition, since the waste heat of the engine 52 is used, power consumption may be minimized when the operating capacity of the compressor 70 is reduced.

Next, when the air conditioner is in the cooling operation mode and is described with reference to FIG. 5 at the time of commercial power output, it is as follows.

The generator 50, the engine 52, the coolant pump 57, the heat medium circulation pump 65, and the waste heat radiating blower 88 are maintained in a stopped state.

In the air conditioner, the refrigerant compressed by the compressor (70) passes through a four-way valve (73), an outdoor heat exchanger (75), an indoor expansion valve (76), an indoor heat exchanger (74), and a four-way valve (73). After being circulated to the compressor 70, the indoor unit Ia supplies cold air.

Next, the air conditioner is a heating operation mode, and will be described with reference to FIG. 6 when outputting commercial power.

The generator 50, the engine 52, the coolant pump 57, the heat medium circulation pump 65, and the waste heat radiating blower 88 are maintained in a stopped state.

The air conditioner, the refrigerant compressed by the compressor 70, the four-way valve 73 and the indoor heat exchanger 74, the indoor expansion valve 76, outdoor expansion valve 77, outdoor heat exchanger 75, waste heat After passing through the supply heat exchanger 80 and the four-way valve 73 in turn, the indoor unit Ia supplies warm air while being circulated to the compressor 70. At this time, the outdoor expansion valve 77 is controlled according to the degree of superheat.

Here, since the waste heat recovered by the waste heat recovery device 60 is not transmitted to the waste heat supply heat exchanger 80, the refrigerant passes through the waste heat supply heat exchanger 80 due to the design characteristics of the refrigerant circulation flow path 79. However, it is not evaporated in the waste heat supply heat exchanger (80).

The cogeneration system and the control method thereof according to the present invention configured as described above output power to the air conditioner, which is advantageous for the operation efficiency of the cogeneration system among generated power and commercial power, depending on the operation mode and the load condition of the air conditioner. Therefore, not only can the system operating efficiency be improved, but the operating cost of the system can be reduced.

In addition, the cogeneration system and the control method thereof according to the present invention have the advantage of minimizing the number of power switching, as well as maximizing operating efficiency and operating cost by providing a hysteresis region.

In addition, the cogeneration system and the control method according to the present invention, there is an advantage that can prevent the crowd of the air conditioner, in particular the compressor during power switching by re-operating after the air conditioner is paused during power switching. .

In addition, the cogeneration system and the control method thereof according to the present invention, since the power switching of the generated power and commercial power is automatically controlled in accordance with the operation mode and load conditions of the air conditioner, the power is actively switched to the system efficiency and Economics can be improved, and inconveniences caused by manual power switching can be prevented, and short circuit accidents caused by simultaneous output of generated power and commercial power due to sub-divisions during power manual switching can be prevented.

In addition, the cogeneration system and the control method according to the present invention, the waste heat of the driving source is supplied to the air conditioner in the outdoor low temperature heating operation mode of the air conditioner, the air conditioner is always at a constant level regardless of the outdoor temperature change It can achieve the heating performance of, and also has the advantage that the efficiency of the system can be maximized.

Claims (11)

A generator; A drive source for driving the generator; A waste heat recovery apparatus for recovering waste heat of the driving source; A power switching device for switching electric power such that any one of generated power and commercial power produced by the generator is output; A power consuming device supplied with the power output through the power switching device; And a controller configured to control the power switching device to switch power when the load of the power consumption device exceeds a power switching boundary according to the load of the power consumption device more than a predetermined time while the power consumption device is in operation. Cogeneration system characterized by the above-mentioned. The method of claim 1, The power consumer is an air conditioner consisting of an indoor unit and an outdoor unit, And the control unit controls the power switching device according to the operating ratio of the indoor unit and the outdoor temperature in which the outdoor unit is installed. The method of claim 1, The power consumer is an air conditioner consisting of an indoor unit and an outdoor unit, And the control unit controls the power switching device according to an operation mode of the air conditioner together with an operation ratio of the indoor unit, which is a load of the power consumption device, and an outdoor temperature in which the outdoor unit is installed. The method according to any one of claims 1 to 3, The power consumer is an air conditioner comprising an outdoor unit including a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and an indoor unit including an indoor expansion valve and an indoor heat exchanger. The air conditioner is a combined heat and power generation system, characterized in that for selectively receiving the waste heat recovered by the waste heat recovery device through a waste heat supply heat exchanger. The method of claim 4, wherein The air conditioner is a cogeneration system characterized in that the refrigerant compressed by the compressor is operated in a cooling cycle circulated to the compressor after passing through the four-way valve, the outdoor heat exchanger and the indoor expansion valve, the indoor heat exchanger and the four-way valve in the cooling operation mode. system. The method of claim 4, wherein When the air conditioner is a heating operation mode and does not use the waste heat of the driving source, the refrigerant compressed in the compressor passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, the outdoor heat exchanger, and the four-way valve in order. Cogeneration system characterized in that it is operated by an outdoor high temperature heating cycle circulated to. The method of claim 4, wherein The air conditioner is a heating operation mode, and when the waste heat of the driving source is used, the refrigerant compressed by the compressor passes through the four-way valve, the indoor heat exchanger, the indoor expansion valve, the outdoor expansion valve, the waste heat supply heat exchanger, and the four-way valve, and is circulated to the compressor. A cogeneration system, characterized in that it is operated by an outdoor low temperature heating cycle. A power switching determination step of determining whether a load of the power consumer device has exceeded a power switching boundary according to the load of the power consumer device by more than a predetermined time when the power consumer operates; If the power switching is determined, the control method of the cogeneration system characterized in that it comprises a power switching step for outputting the power to the power consumer device other than the pre-selected power generation power and commercial power. The method of claim 11, The power consumer is an air conditioner consisting of an indoor unit and an outdoor unit, The power switching boundary is set according to the operation ratio of the indoor unit and the outdoor temperature according to the operation mode of the air conditioner. The power switching determination step, When the air conditioner is in the cooling operation mode, the power generation power output When the driving ratio of the indoor unit is smaller than the first boundary ratio by a predetermined ratio or more and the outdoor temperature is smaller than the first boundary temperature by a predetermined temperature or more, the switching to the commercial power is determined; When the air conditioner is in a cooling operation mode and commercial power output When the driving ratio of the indoor unit is larger than the second boundary ratio by a predetermined ratio or more, or when the outdoor temperature is larger than the second boundary temperature by a predetermined temperature or more, switching to generation power is determined; When the air conditioner is in the heating operation mode, the power generation power output When the driving ratio of the indoor unit is smaller than the third boundary ratio by a predetermined ratio or more and the outdoor temperature is larger than the third boundary temperature by a predetermined temperature or more, switching to commercial power is determined; When the air conditioner is the heating operation mode, the commercial power output And when the operation ratio of the indoor unit is larger than the fourth boundary ratio by more than a predetermined ratio or the outdoor temperature is greater than or equal to the fourth boundary temperature by more than the predetermined temperature, switching to the generated power is determined. The method according to claim 8 or 9, The power switching step, the control method of the cogeneration system, characterized in that for switching the power after the power consumption device pauses. The method according to claim 8 or 9, The power switching step is a control method of a cogeneration system, characterized in that for switching a power after a predetermined time after the power is selected.

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