JP4267587B2 - Air conditioning and power generation system - Google Patents

Description

  The present invention relates to an air conditioning / power generation system that simultaneously performs air conditioning and power generation by driving a compressor and a generator by an engine.

In a conventional engine-driven air conditioner, a compressor that compresses a refrigerant is driven by an engine such as a gas engine to perform an air conditioning operation. In recent years, a generator is connected to the gas engine, and the power generated by the generator is supplied to a load device such as a blower that blows air to an outdoor heat exchanger or a cooling water pump that cools the engine. Realization of a supply-less air conditioner is being sought (for example, see Patent Document 1).
In general, when a demand controller is installed and a power reduction instruction is output from the demand controller so that the commercial power usage does not exceed the contract power, control is performed so that the power consumption is within the contract power.
JP-A-5-231745

  However, an air conditioning / power generation system in which the function of the demand controller is added to an air conditioning / power generation system that outputs the generated power of the generator connected to the gas engine to a commercial system has not been proposed yet.

  Accordingly, an object of the present invention is to provide an air conditioning / power generation system that can solve the above-described problems of the conventional technology and efficiently store the power usage amount in the contract power when a power reduction instruction is output. There is to do.

  To achieve the above object, the present invention comprises an air conditioner having a compressor driven by an engine, an outdoor heat exchanger, a decompression device and an indoor heat exchanger, and a generator driven by the engine, Connected to this generator is a grid-connected inverter to provide electrical output to the commercial system and a demand controller that outputs a power reduction instruction according to the contracted power of the commercial system. In this case, the power generation output of the generator is increased.

  In the present invention, when a power reduction instruction is output from the demand controller, in response to the power reduction instruction, the power from the generator is increased and output to the commercial system. It will fit.

In this case, the compressor is composed of a plurality of compressors having large and small capacities, and the plurality of compressors are connected in parallel to the engine via electromagnetic clutches. When a predetermined reduction level is output in correspondence with the reduction level of the power reduction instruction, the clutch disengagement according to the corresponding disengagement level may be performed, and the power generation output of the generator may be increased in this state.
In the present invention, when the output of the generator is increased, the clutch is disengaged according to a predetermined disengagement level in advance, so that the load on the compressor side is reduced, and power generation with an added amount of this load reduction becomes possible. Become.

When the output of the generator is increased, the inverter may be controlled so that the power generation amount of the generator becomes a power generation amount corresponding to the engine allowable load at the current rotational speed.
In this configuration, since the inverter is controlled so that the power generation amount corresponding to the engine allowable load at that rotational speed is achieved, even if the engine allowable load is fully generated and the air conditioning load varies and the rotational speed varies, It is possible to obtain the maximum amount of power that can be generated at that rotational speed. Since the power generation is full of the engine allowable load, an excessive load is not applied to the engine, and engine durability is ensured. In addition, the amount of commercial power purchased is reduced by generating power with full engine allowable load.

  An acquisition means for acquiring the current engine load is provided, and the power generation amount obtained from the difference between the engine load acquired by the acquisition means and the engine allowable load at the current rotational speed is added to the current power generation amount, The inverter may be controlled so that the power generation amount becomes the added power generation amount. Moreover, the determination means which determines whether the added electric power generation amount is below the predetermined maximum electric power generation amount may be provided, and the inverter may be controlled according to the determination result of the determination means. A throttle valve that adjusts the amount of air supplied to the engine may be provided, and the current engine load may be estimated according to the opening of the throttle valve.

  In the present invention, when a power reduction instruction is output from the demand controller, the power from the generator is increased and output to the commercial system in response to the reduction instruction, so that the power usage amount of the commercial system falls within the contract power. .

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a gas engine driven air conditioner 1. The air conditioner 1 includes an outdoor unit 2 and a plurality of indoor units 3a to 3c, which are connected by an inter-unit pipe 4 including a liquid pipe 4a and a gas pipe 4b. The outdoor unit 2 accommodates a gas engine 10, a generator 11 that generates power using the driving force of the gas engine 10, and a compressor 12 that compresses the refrigerant using the driving force of the gas engine 10. The gas engine 10 generates a driving force by combusting an air-fuel mixture of a fuel such as a gas supplied via a fuel adjustment valve 7 and air supplied via a throttle valve 8.

  The compressor 12 includes compressors 12a and 12b having large and small capacities, and two units are connected in parallel to the gas engine 10 via electromagnetic clutches 14a and 14b, respectively. The discharge pipes 12c of the compressors 12a and 12b are connected in the order of the plate heat exchanger 31, the four-way valve 15, and the outdoor heat exchanger 17, and each of the outdoor heat exchangers 17 is connected to the outdoor heat exchanger 17 via the liquid pipe 4a. Expansion valves 19a to 19c and indoor heat exchangers 21a to 21b of the indoor unit 3 are connected. A four-way valve 15 is connected to the indoor heat exchangers 21a to 21b via a gas pipe 4b. Are connected to the compressors 12a and 12b. Further, the discharge pipe 12c and the suction pipe 12d of the compressors 12a and 12b are connected by a bypass pipe 18, and an unload bypass valve 20 is connected to the bypass pipe 18.

  Incidentally, when the compressors 12a and 12b are driven, if the four-way valve 15 is switched and if it is heating switching, the compressors 12a and 12b, the four-way valve 15 and the indoor heat exchange are indicated as indicated by solid arrows. The refrigerant circulates in the order of the chambers 21a to 21b, the expansion valves 19a to 19c, and the outdoor heat exchanger 17, and the room is heated by the refrigerant condensation heat in the indoor heat exchangers 21a to 21b. On the contrary, if the four-way valve 15 is switched to cooling, the compressors 12a and 12b, the four-way valve 15, the outdoor heat exchanger 17, the expansion valves 19a to 19c, and the indoor heat exchanger are indicated by the broken arrows. The refrigerant circulates in the order of 21a to 21b, and the room is cooled by the refrigerant evaporating heat in the indoor heat exchangers 21a to 21b.

Next, a cooling device for the gas engine 10 will be described.
The gas engine 10 is water-cooled, and the cooling water circulated through the water jacket of the gas engine 10 is supplied to the radiator 25 through the first three-way valve 22, the reverse power flow heater 23, and the second three-way valve 24. The The radiator 25 is provided with the outdoor heat exchanger 17, and these are cooled by air sent by the same blower 26, and the cooling water passing through the radiator 25 is supplied to the cooling water pump 27 and the exhaust gas heat exchanger 29. It flows in order and is returned to the water jacket of the gas engine 10.
Exhaust gas from the gas engine 10 is passed through the exhaust gas heat exchanger 29, and this exhaust gas is discharged out of the outdoor unit 2 through the exhaust top 30.

The first three-way valve 22 described above is automatically switched according to the cooling water temperature. That is, when the cooling water temperature is lower than the predetermined temperature, the cooling water from the water jacket of the gas engine 10 bypasses the radiator 25 and is directly led to the cooling water pump 27 and the exhaust gas heat exchanger 29 in this order, Return to the jacket.
The second three-way valve 24 is switched, for example, during heating operation. In this case, the cooling water bypasses the radiator 25, passes through the plate heat exchanger 31, and flows in the order of the cooling water pump 27 and the exhaust gas heat exchanger 29, Returned to the water jacket.

Next, a power generation system using the generator 11 will be described.
A grid interconnection inverter 33 is connected to the generator 11. The grid interconnection inverter 33 converts the three-phase AC power from the generator 11 into DC power through an AC / DC converter, and It is converted into 200 V three-phase AC power and output to the commercial system 35. The commercial system 35 includes a commercial power source 36, a breaker 37, and a customer load 38, and the grid interconnection inverter 33 is connected between the breaker 37 and the customer load 38.

  Further, the grid interconnection inverter 33 appropriately supplies power to the above-described reverse flow heater 23 and is communicably connected to the outdoor controller 39 of the outdoor unit 2 via the communication line 40. The outdoor controller 39 obtains operating power from the commercial system 35 via the power line 41 and is communicably connected to the indoor controller of each indoor unit 3 via the communication line 42.

A power detector 43 installed between the commercial power source 36 and the breaker 37 is connected to the grid interconnection inverter 33. The power detector 43 acquires the power value supplied to the commercial grid 35 in real time, and the acquired power value data is input to the grid interconnection inverter 33 and is transmitted to the outdoor controller 39 via the communication line 40. Sent.
Further, the grid interconnection inverter 33 has a function of controlling the power generation amount of the generator 11 and decreases or increases the power generation amount as necessary.

In the above configuration, for example, when the load on the compressors 12a and 12b increases according to the air conditioning request on the indoor unit 3 side, and the power generation request increases according to the increase in the consumer load 38 of the commercial system 35, the engine The load of 10 increases.
The customer load 38 is constantly monitored by the power detector 43, the grid interconnection inverter 33, and the outdoor controller 39.

In this configuration, a demand controller 51 that outputs a power reduction instruction according to the contract power of the commercial system is installed.
The demand controller 51 outputs, for example, four levels of power reduction instructions from level 0 to level 3, and if the output is level 0, there is a considerable margin in the amount of power used up to the contract power. The level of danger gradually increases, and level 3 indicates that the contract power has been approached. The demand controller 51 outputs a power reduction instruction to the outdoor controller 39, and the outdoor controller 39 permits the grid interconnection inverter 33 to increase the power generation output according to the level of the power reduction instruction.

FIG. 2 shows a control flow.
In this processing flow, first, the level of the power reduction instruction from the demand controller 51 is determined (S1). If the instruction level is the power reduction level 0, the air conditioning priority operation is performed. If the instruction level is the power reduction level 1 or more, the power generation priority operation is performed.

In the case of power reduction level 0, there is a considerable margin before contract power, and the system's original air conditioning priority operation is performed.
In this air conditioning priority operation, the current load level of the engine 10 is acquired (S2). The current load level is estimated according to the valve opening of the throttle valve 8 (FIG. 1). The throttle valve 8 is an air amount adjusting valve of the engine 10, and the opening degree of the throttle valve 8 is classified into, for example, seven stages (level: 0 <high load> to 6 <low load>). In addition, if the associated load levels are obtained in advance and mapped, for example, the load level can be estimated according to the valve opening of the throttle valve 8.

Next, the power generation amount obtained from the difference between the current load level and the engine allowable load level is added to the current power generation amount (S3). Specifically, for example, as shown in FIG. 3, when the curve T is an engine allowable load level (allowable torque), the current engine load level T1 corresponding to the current engine speed R1 and the speed R1 thereof. The load level T3 that is the difference from the engine allowable load level T2 is determined, and the power generation amount Q1 corresponding to the load level T3 is determined from a predetermined load level / power generation amount map or the like, or from a predetermined arithmetic expression, The obtained power generation amount Q1 is added to the current power generation amount Q.
And it is determined whether this electric power generation amount Q2 (= Q1 + Q) is below the predetermined maximum electric power generation amount (S4). The maximum power generation amount may be a specification (rated) power generation amount or a predetermined power generation amount less than that. This maximum power generation amount varies depending on the rotation speed of the engine 10 and the load level.

  In S4, if the power generation amount Q2 is equal to or less than the maximum power generation amount, the grid interconnection inverter 33 is permitted to generate the power generation amount Q2 (S5). If the power generation amount is equal to or greater than the maximum power generation amount, in order to prevent an overload of the engine 10, the grid interconnection inverter 33 is not permitted to generate the power generation amount Q2, but the power generation stopped at the maximum power generation amount is permitted (S6).

In this configuration, in the case of the power reduction level 0, when the air conditioning request increases, the engine speed increases according to the air conditioning request, and the compressor 12 is driven according to the engine speed.
Then, the refrigerant discharge amount according to this rotational speed is obtained, and air conditioning according to the air conditioning request is performed by circulation of this refrigerant amount.

In the state where the air-conditioning operation is performed at this rotational speed, a margin (corresponding to the load T2) is generated in the engine load with reference to FIG. In this configuration, since the output of the inverter 33 is controlled so that the power generation amount corresponding to the engine allowable load at that rotational speed is achieved, power generation at the full engine allowable load is always performed, the air conditioning load varies, and the rotational speed is Even if it fluctuates, it is possible to obtain the maximum amount of power that can be generated at that rotational speed.
In addition, since the engine is capable of generating the full allowable load of the engine, an excessive load is not applied to the engine 10 and engine durability is ensured.

On the other hand, if the power reduction level is 1 or more in S1, the risk changes for each level, and therefore power generation priority operation according to the risk is performed.
In this case, first, power reduction levels 1 to 3 are acquired (S7). As described above, the risk gradually increases from the reduction level 1 to the reduction level 3, and at the reduction level 3, the contract power is considerably approached. Next, it is determined whether or not the maximum power generation amount is output at the current engine speed, and based on this, the clutch disengagement level of the compressor is selected (S8). This maximum power generation amount is the maximum power generation amount stipulated in this facility. When the maximum power generation amount is exceeded, the load on the compressor side is reduced. A separation level is selected (S9).

As shown in FIG. 1, the compressors 12a and 12b have large and small capacities, the capacity of the compressor 12a is larger than the capacity of the compressor 12b, and the electromagnetic clutches 14a and 14b are correspondingly set in large and small. Has been.
As shown in FIG. 3, the clutch disengagement level is classified into four stages of disengagement levels 0 to 3. When disengagement level 0 is selected, two compressors are connected at the same time, and disengagement level 1 Then, a compressor with a large capacity is connected, a compressor with a small capacity is connected at the disconnection level 2, and all the compressors are disconnected at the disconnection level 3.
In the selection of the clutch disengagement level in S9, for example, referring to FIG. 4, when the power reduction level 1 is acquired, the disengagement level 1 is selected, and when the power reduction level 2 is obtained, the disengagement level 2 is selected, When power reduction level 3 is obtained, disconnect level 3 is selected, thereby reducing the compressor load.

When the clutch disengagement level is selected, the processes of S2 to S6 are performed. In this case, the current load level acquired in S2 has a margin (corresponding to the load T2) in the engine load corresponding to the reduction of the compressor load by the selection of the disconnection level.
Therefore, by controlling the output of the inverter 33 so that the power generation amount corresponds to the engine allowable load at the current rotational speed, it is possible to add the power generation amount corresponding to the engine load margin.

  In S8, when the maximum power generation amount has been reached at the current engine speed, the maximum power generation is performed with the clutch disengagement level remaining unchanged.

In the present embodiment, when a power reduction level 1 or higher is output from the demand controller 51, the clutch disengagement level of the compressor is selected according to the power reduction levels 1 to 3, and in this state, power generation with full engine allowable load is achieved. Is done.
For example, referring to FIG. 4, when disconnection level 1 is selected, only the large capacity compressor 12a is connected, and the load on the compressor side is reduced accordingly. Therefore, referring to FIG. 3, the current engine load level T1 decreases, the load level T3 that is different from the engine allowable load level T2 at the rotational speed R1 increases, and the power generation amount Q1 corresponding to this load level T3 Can be increased.
Referring to FIG. 4, for example, when disconnection level 3 is selected, all the compressors are disconnected and the load on the compressor side is greatly reduced.
In this case, referring to FIG. 3, the load level T3, which is the difference between the current engine load level T1 and the engine allowable load level T2, greatly increases, and the power generation amount Q1 corresponding to the load level T3 can be generated.

  In this configuration, the clutch is disengaged according to a predetermined disengagement level in advance according to the output reduction level. Therefore, when the output of the generator is increased, the load on the compressor side is reduced, and this load is reduced. It is possible to generate electricity with an additional minute. Therefore, when the power reduction instruction is output, the power generation amount increases efficiently, so that the amount of commercial power used can be reduced and the power usage amount can be kept within the contract power without reducing the customer load 38. .

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to this. For example, the grid interconnection inverter 33 is provided separately from the outdoor unit 2, but may be housed integrally in the outdoor unit 2. Further, when a plurality of outdoor units 2 are installed, a grid interconnection inverter 33 is installed in each outdoor unit 2, and these grid interconnection inverters 33 are connected by a converter, and this converter is connected to each grid interconnection inverter 33. An output control instruction may be issued. In the present embodiment, the power supplied from the inverter is three-phase 200V, but may be three-phase 100V or a single-phase three-wire system.

It is a circuit diagram showing one embodiment of the present invention. It is a figure which shows a processing flow. It is a figure explaining an engine allowable load level. It is a figure explaining a clutch disengagement level.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine drive type air conditioner 2 Outdoor unit 3 Indoor unit 8 Throttle valve 10 Engine 11 Generator 33 Grid connection inverter 35 Commercial system 36 Commercial power supply 37 Breaker 38 Consumer load 39 Outdoor controller 43 Power detector 51 Demand controller

Claims (6)

An air conditioner having a compressor driven by an engine, an outdoor heat exchanger, a decompression device and an indoor heat exchanger, and a generator driven by the engine, and a grid-connected inverter connected to the generator And a demand controller that outputs electric power to the commercial system and outputs a power reduction instruction according to the contract power of the commercial system,
An air conditioning and power generation system characterized in that when a power reduction instruction is output from the demand controller, the power generation output of the generator is increased.   The compressor is composed of a plurality of compressors having large and small capacities, and the plurality of compressors are connected in parallel to the engine via electromagnetic clutches, respectively, and the disconnection level of the electromagnetic clutches is determined by the power reduction instruction. 2. The clutch disengagement according to the corresponding disengagement level is performed when a predetermined reduction level is output in correspondence with the reduction level of the generator, and the power generation output of the generator is increased in this state. Air conditioning and power generation system.   2. The inverter is controlled such that when the output of the generator is increased, the power generation amount of the generator becomes a power generation amount corresponding to the engine allowable load at the current rotation speed. 2. The air conditioning and power generation system described in 2.   An acquisition means for acquiring the current engine load is provided, and the power generation amount obtained from the difference between the engine load acquired by the acquisition means and the engine allowable load at the current rotational speed is added to the current power generation amount, and the power generation 4. The air conditioning and power generation system according to claim 3, wherein the inverter is controlled so that the power generation amount of the machine becomes the added power generation amount.   5. The air-conditioner / air conditioner according to claim 4, further comprising a determination unit that determines whether or not the added power generation amount is equal to or less than a predetermined maximum power generation amount, and the inverter is controlled according to a determination result of the determination unit. Power generation system. 6. The air conditioning / power generation system according to claim 4, further comprising a throttle valve that adjusts an air supply amount to the engine, and estimating a current engine load according to a valve opening degree of the throttle valve.

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