JP4382004B2 - 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.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art, and when the power reduction instruction is output at the time of low-speed engine rotation, the power consumption can be efficiently contained within the contract power. The purpose is to provide an air conditioning and power generation system.

The present invention includes 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 the generator is connected to the grid. Connect the power system inverter to output power to the commercial system, and output a multi-stage power reduction instruction that includes the power reduction level where the power usage is sufficient for the contracted power according to the contracted power of the commercial system comprising a demand controller which, when the power decrease command power reduction level there is a margin to the contract power is output, together with the air conditioning priority operation is performed, the power range that can be generated by the current rotational speed of the engine is performed, the power When the reduction level rises, power generation priority operation is performed, and when the current engine speed can be used, the power generation amount allowed by the grid interconnection inverter as it is In the power generation amount increases, not be compatible with the current engine speed, by increasing the rotational speed until the engine rotational speed corresponding to power reduction level, to increase the power generation amount of electrical generation to the amount of permitted system interconnection inverter, Control means for reducing the air conditioning capability corresponding to the increased engine speed increase is provided.

When the engine rotates at a low speed, the power generation voltage level of the generator decreases, and even if a power reduction instruction is output, the output of the generator may not be obtained.
In this configuration, the power generated by the generator is increased by increasing the engine speed according to this power reduction level, and this is output to the commercial grid, so the power usage of the commercial grid is within the contract power. Can fit. Further, when the engine speed is increased, the air conditioning capability increases. However, in this configuration, since the air conditioning capability corresponding to the increase is reduced by the control means, it is possible to perform an operation that meets the air conditioning requirements.

  In this case, the control means may control the opening degree of the indoor electronic expansion valve or the outdoor electronic expansion valve constituting the decompression device to reduce the increased air conditioning capability. The control means may include a bypass valve provided in a bypass pipe connecting the discharge pipe and the suction pipe of the compressor, and the bypass valve may be opened and closed to reduce the increased air conditioning capability. Further, the compressor is composed of a plurality of compressors having large and small capacities connected to the engine via electromagnetic clutches, respectively, and the control means disengages any one of the electromagnetic clutches. The increased air conditioning capacity may be reduced.

  In the present invention, the generated power of the generator is increased by increasing the engine speed in accordance with the power reduction level, and this is output to the commercial system. Therefore, the power consumption of the commercial system is kept within the contract power. In addition, since the air conditioning capability corresponding to the increase in the engine speed is reduced, it is possible to operate in accordance with the air conditioning requirements.

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 a plate heat exchanger 31, a four-way valve 15, an outdoor heat exchanger 17, and an outdoor expansion valve 16, and the liquid pipe 4a is connected to the outdoor expansion valve 16. The expansion valves 19a to 19c and the indoor heat exchangers 21a to 21b of each indoor unit 3 are connected to each other, and the four-way valve 15 is connected to the indoor heat exchangers 21a to 21b via the gas pipe 4b. Compressor 12a, 12b is connected to the four-way valve 15. 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, the outdoor expansion valve 16, 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 outdoor expansion valve 16, and the expansion valves 19a to 19c are indicated by broken arrows. The refrigerant circulates in the order of the indoor heat exchangers 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 during cooling operation.
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, there is a considerable margin before the contract power, and the system's original air conditioning priority operation is performed. In this air conditioning priority operation, power generation is performed within a range where power can be generated at the current rotational speed of the engine 10 (S2).

If the power reduction level is 1 or more in S1, the risk changes for each level, and therefore power generation priority operation is performed according to the risk. In this power generation priority operation, it is determined whether or not the power generation amount that can be generated at the current engine speed can correspond to the power generation output increase amount permitted by the grid interconnection inverter 33 according to the level of the power reduction instruction ( S3).
If the current engine speed can be used, the power generation amount is increased to the power generation amount permitted by the grid interconnection inverter 33 (S4).

If the current engine speed cannot be dealt with in S3, the engine speed is increased to the engine speed corresponding to the level of the power reduction instruction (S5), and in this state, the power generation amount allowed by the grid interconnection inverter 33 is generated. The amount is increased (S6). The increase in the rotational speed is determined in advance according to the level of the power reduction instruction. For example, if level 1 is output, the current rotational speed is increased by 100 rpm, if level 2 is output, the current rotational speed is increased by 200 rpm, if level 3 is output, the current rotational speed is increased by 300 rpm, etc. It is.
In S <b> 3, “the case where the current engine speed cannot be handled” corresponds to the case where the engine is driven at a low speed. This is because at the time of the engine low speed rotation, the power generation voltage level of the generator 11 is lowered, and even if a power reduction instruction is output, the output of the generator 11 may not be obtained.

  In S5, when the engine speed is increased according to the power reduction level, if the engine speed is left as it is, the air conditioning capacity increases and the operation exceeds the air conditioning request, and an excessive load is applied to the engine. In this configuration, the air conditioning capacity corresponding to the increase is reduced by the following procedure, and an operation corresponding to the air conditioning request becomes possible. In this cooling operation, when the blowing temperature of the air blown through the indoor heat exchangers 21a to 21b is detected and this blowing temperature is lower than the predetermined temperature (S7), it is determined that the air conditioning capacity is excessively increased, First, the expansion valves (indoor electronic expansion valves) 19a to 19c are adjusted in the closing direction (S8). In this adjustment, the difference between the refrigerant temperature E3 at the outlet of the indoor heat exchangers 21a to 21b and the refrigerant temperature E1 at the inlet is increased, and the air conditioning capability is reduced.

  Next, when the refrigerant temperature E1 at the inlet is detected and the refrigerant temperature E1 is lower than the predetermined temperature (S9), freezing at the inlet is expected, so the unloading bypass valve 20 is adjusted in the opening direction. (S10). By this adjustment, a part of the refrigerant discharged from the compressor is returned to the suction pipe of the compressor, and the air conditioning capacity is reduced.

FIG. 3 shows a control flow during heating operation.
In this processing flow, the processes from S7 to S10 in FIG. 2 are replaced with the processes from S17 to S20, and the other processes are the same. That is, in this heating operation, the temperature of air blown out through the indoor heat exchangers 21a to 21b is detected, and when this temperature is higher than the predetermined temperature (S17), it is determined that the air conditioning capacity has increased excessively. First, the outdoor expansion valve (outdoor electronic expansion valve) 16 is adjusted in the closing direction (S18).
In this adjustment, the difference between the refrigerant temperature E3 at the outlet of the outdoor heat exchanger 17 and the refrigerant temperature E1 at the inlet is increased, and the air conditioning capability is reduced.

  Next, when the refrigerant temperature E1 at the inlet of the outdoor heat exchanger 17 is detected and the refrigerant temperature E1 is lower than the predetermined temperature (S19), freezing at the inlet is expected, so the bypass valve 20 is opened. (S20). By this adjustment, a part of the refrigerant discharged from the compressor is returned to the suction pipe of the compressor, and the air conditioning capacity is reduced.

In this configuration, during both cooling and heating operations, when the engine rotates at low speed, the engine speed is increased to the engine speed corresponding to the power reduction instruction level, and the power generation amount is increased to the power generation amount permitted to the grid interconnection inverter 33. Let
Therefore, since the generated power of the generator 11 is increased and output to the commercial system, the usage amount of the commercial power can be reduced and the power usage amount can be kept within the contract power without reducing the consumer load 38. it can.

  In addition, when the engine speed is increased, the air conditioning capability increases. However, in this configuration, the outdoor controller 39 reduces the air conditioning capability corresponding to the increased amount, so that operation that meets the air conditioning requirements is possible. Become.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to this. For example, when the air conditioning capacity corresponding to the increased amount is reduced, the compressor capacity may be reduced by disconnecting one of the electromagnetic clutches 14a and 14b, thereby reducing the air conditioning capacity. Further, the grid interconnection inverter 33 is provided separately from the outdoor unit 2, but may be housed integrally in the outdoor unit 2. 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 converters. An output control instruction may be given to the inverter 33. 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 the processing flow at the time of air_conditionaing | cooling operation. It is a figure which shows the processing flow at the time of heating operation.

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 Customer load 39 Outdoor controller (control means)
43 Power detector 51 Demand controller

Claims (4)

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 A demand controller that outputs electricity to the commercial system and outputs a multi-stage power reduction instruction according to the contracted power of the commercial system. When a power reduction instruction at a power reduction level with sufficient contract power is output, air conditioning priority operation is performed, and power generation is performed within the range that can generate power at the current engine speed, and the power reduction level increases If power generation priority operation is performed and the current engine speed can be used, the power generation amount up to the power generation amount permitted by the grid-connected inverter is maintained. Increases, not be compatible with the current engine speed, by increasing the rotational speed until the engine rotational speed corresponding to power reduction level, to increase the power generation amount of electrical generation to the amount of permitted system interconnection inverter was increased engine An air-conditioning / power generation system comprising a control means for reducing the air-conditioning capacity corresponding to the increase in the rotational speed .   2. The air conditioning and power generation according to claim 1, wherein the control means controls the opening degree of the indoor electronic expansion valve or the outdoor electronic expansion valve constituting the pressure reducing device to reduce the increased air conditioning capacity. system.   The control means has a bypass valve provided in a bypass pipe connecting a discharge pipe and a suction pipe of the compressor, and opens and closes the bypass valve to reduce the increased air conditioning capacity. Item 3. The air conditioning / power generation system according to item 1 or 2.   The compressor is composed of a plurality of compressors of large and small capacities connected to the engine via electromagnetic clutches, respectively, and the control means disconnects one of the electromagnetic clutches to increase the amount of increase. The air conditioning / power generation system according to any one of claims 1 to 3, wherein the air conditioning capacity is reduced.

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