JP4585422B2 - Gas heat pump type air conditioner - Google Patents

Description

  The present invention relates to a gas heat pump type air conditioner including a multi-combination outdoor unit that uses a plurality of outdoor unit units in combination.

Conventionally, a gas engine operated with gas fuel such as city gas uses a refrigerant circuit having elements such as an indoor heat exchanger, a compressor, an outdoor heat exchanger, and a throttle mechanism, and drives the compressor to A gas heat pump type air conditioner (hereinafter referred to as “GHP”) that performs air conditioning operations such as cooling and heating is known. In the indoor air conditioning in this GHP, the refrigerant carries heat exchanged with indoor air (hereinafter referred to as “indoor air”) in the indoor heat exchanger to the outdoor heat exchanger, and exchanges heat with the outside air in the outdoor heat exchanger. Has been done.
Some GHPs described above include a multi-combination outdoor unit that connects and uses a plurality of outdoor unit units.

Further, in an air conditioner (hereinafter referred to as “EHP”) having a plurality of electric compression mechanisms that perform inverter control, capacity control operation is individually performed by inverter control, and inverter driving is performed according to a required load. Capacity control is performed with one unit from the lowest possible frequency to the intermediate frequency before the highest frequency, and for larger loads, capacity control operation is performed between the lowest frequency and the highest frequency that can drive multiple units at the same time. It has been proposed that the capacity can be continuously controlled from the minimum load to the large load. (For example, see Patent Document 1)
JP-A-2-267469

As described above, in an air conditioner including a plurality of compression mechanisms (outdoor unit units), if the refrigerant circulation amount is different for each outdoor unit, there is a problem in the bias of refrigerant and lubricating oil due to cooling operation and heating operation. It becomes. Such a bias of refrigerant and lubricating oil is likely to cause a difference in pressure loss, and the higher the rotation speed range of the compressor, the higher the OC% (the amount of oil discharged with respect to the amount of refrigerant discharged). The operation area is more prominent. The reason why the lubricating oil is biased is that the lubricating oil that lubricates the compressor circulates together with the refrigerant.
Therefore, in the case where a plurality of outdoor unit units are operated at the same time, in order to prevent the refrigerant and lubricating oil from being biased, it is common practice to align the compressor circulation amount of each unit.

  However, in a GHP equipped with a multi-combination outdoor unit, if the operation is performed to make the compressor circulation amount uniform during the small capacity operation to the medium capacity operation, for example, in terms of performance, even a single unit of the outdoor unit can be operated Even in this case, there is a problem that the efficiency (COP) is lowered by operating a plurality of units simultaneously. In other words, the GHP that drives the compressor with a gas engine is capable of operating multiple units simultaneously, especially in the small to medium capacity operating range, compared to the EHP capacity control that drives the compressor with an inverter-controlled motor. This is not preferable because a rotational speed region that is disadvantageous in terms of efficiency of the gas engine is used.

Furthermore, in the case of GHP using a gas engine of an internal combustion engine, maintenance is required every predetermined operation time. Therefore, by operating with one outdoor unit as much as possible up to a medium capacity operation region, It is desired to extend the maintenance period and product life of the multi-combination outdoor unit as a whole by shortening the operation time.
The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the efficiency of the entire apparatus and extend the maintenance period and product life in a GHP equipped with a multi-combination outdoor unit. It is in.

In order to solve the above problems, the present invention employs the following means.
The present invention is a gas heat pump type air conditioner equipped with a multi-combination outdoor unit that is used by connecting a plurality of outdoor unit units,
A small / medium amount refrigerant operation control region is provided to operate one of the outdoor unit and cover the refrigerant circulation amount from the minimum circulation amount to the allowable circulation amount, and the demand for the refrigerant circulation amount exceeds the allowable circulation amount and the outdoor This operation is performed when the additional operation of the outdoor unit is started, and the outdoor unit that is continuously operated from the small and medium amount refrigerant operation control region is operated so as to maintain the continuity of the refrigerant circulation amount during the startup of the outdoor unit that has been additionally operated. A complementary control area to be controlled is provided.

According to such a gas heat pump type air conditioner, a small-medium amount refrigerant operation control region is provided that operates one outdoor unit and covers the refrigerant circulation amount from the minimum circulation amount to the allowable circulation amount, and the refrigerant circulation amount. This is implemented when the additional unit operation is started when the additional unit operation exceeds the allowable circulation amount, and the outdoor unit that is continuously operated from the low-medium-quantity refrigerant operation control region is being activated. The supplementary control area that is controlled to maintain the continuity of the refrigerant circulation amount is provided with a wide range of operation by one outdoor unit, and in the supplementary control area, the operation of one outdoor unit is started. When performing additional operation, for example, an outdoor unit that is continuously operated from the small / medium amount refrigerant operation control region at the start of compressor protection increases the circulating refrigerant amount. It can maintain continuity of the total circulation amount of refrigerant supplied from the bets.
The refrigerant circulation amount in this case can be read as the rotation speed of the gas engine that drives the compressor.

  In the above invention, when the demand for the refrigerant circulation amount increases after the completion of the complementary control region, it is preferable that the outdoor unit that is continuously operated from the small and medium amount refrigerant operation region is operated at a maximum efficiency point. As a result, one of the outdoor unit units is operated at a maximum efficiency point, so that the control is stable and efficient operation is possible. That is, the outdoor unit that is additionally operated is controlled to compensate for the refrigerant circulation amount that is insufficient only by the outdoor unit that is fixedly operated at the maximum efficiency point.

  In the above invention, after the additional operated outdoor unit reaches the maximum efficiency point, when the demand for the refrigerant circulation amount further increases, the refrigerant circulation amount of all the outdoor unit operated is set to the same amount. It is preferable that the bias of the refrigerant and the lubricating oil can be prevented.

According to the present invention described above, since the area in which the outdoor unit can be operated by one unit has been maximized, the maintenance period and product life of the entire apparatus affected by the operation time can be extended. In particular, we have expanded the range in which the outdoor unit is operated with a single unit in the operating range of small to medium capacity, where the bias of refrigerant and lubricating oil is relatively unlikely to occur. This contributes to efficiency improvement.
Also, the outdoor unit is fixed at the highest efficiency point, and the additional outdoor unit is operated to compensate for the shortage of the refrigerant circulation amount supplied from the outdoor unit that is operated at the highest efficiency point. Therefore, continuous capacity control over a wide range is performed, and efficient operation as a whole apparatus becomes possible.
As a result, the GHP equipped with the multi-combination machine of the present invention has the remarkable effect of improving the efficiency of the entire apparatus and extending the maintenance period and product life.

Hereinafter, as an embodiment of an air conditioner according to the present invention, a configuration example of a gas heat pump type air conditioner (GHP) including a multi-combination outdoor unit will be described based on the drawings.
FIG. 5 is a circuit diagram showing the overall configuration of the GHP according to the present invention.
The GHP (air conditioner) 1 includes one or a plurality of indoor unit units 3 arranged in a room to be air-conditioned, a plurality of outdoor unit units 5 arranged outdoors, an indoor unit unit 3 and an outdoor unit 5 The refrigerant circuit 7 is configured to circulate the refrigerant between them. The illustrated GHP 1 includes a multi-combination outdoor unit that connects and uses two outdoor unit units 5 and 5. The multi-combination outdoor unit joins the refrigerant outlet pipe and the refrigerant return pipe to each other. It is connected with each indoor unit 3 via the main refrigerant pipe 7a. In addition, the main refrigerant | coolant piping 7a is piping which comprises a part of refrigerant circuit 7 through which a refrigerant | coolant circulates by repeating a state change.

Each indoor unit 3 includes an indoor heat exchanger (heat absorber, radiator) 9, an indoor electronic expansion valve (throttle portion) 11 that decompresses and expands high-pressure refrigerant during cooling operation, and an indoor electronic expansion valve 11 is provided with a strainer 13 that removes foreign matter disposed before and after 11 and a temperature sensor 15 that detects the temperature of the refrigerant.
The indoor heat exchanger 9 functions as an evaporator that removes heat from the indoor air (room air) during cooling operation and evaporates the low-temperature and low-pressure liquid refrigerant, and releases heat to the indoor air during heating operation. It functions as a condenser that condenses the refrigerant.

As shown in FIG. 6, for example, the outdoor unit 5 is divided into two large components inside.
The first component part is a part that constitutes a refrigerant circuit together with the indoor unit 3 centering on devices such as a compressor and an outdoor heat exchanger described later, and is hereinafter referred to as a “refrigerant circuit unit”. In addition, the second component part is a part including a gas engine for driving the compressor and a device attached thereto, and is hereinafter referred to as a “gas engine part”.

The refrigerant circuit section includes a compressor 17, an oil separator 19, a four-way valve (switching section) 21, an outdoor heat exchanger (heat absorber, radiator) 23, an outdoor fan 24, an outdoor expansion valve (throttle section) 25, and a receiver. 27, supercooling coil (cooling heat exchanger) 29, water heat exchanger 31, check valve 33, electromagnetic valve 35 that is selectively opened and closed in accordance with operation control, main refrigerant pipe 7a leading to the indoor side, etc. Are provided with an operation valve 36, a strainer 13 and the like for connecting the local connection pipe and the outdoor side, and each is connected by a refrigerant circuit 7.
The outdoor unit 5 is also provided with a control unit 37 that controls at least the indoor electronic expansion valve 11 and the outdoor expansion valve 25 based on outputs from a temperature sensor, a pressure sensor, and the like.

The compressor 17 is driven by a gas engine 53, which will be described later, and compresses a low-temperature and low-pressure gas refrigerant sucked from any of the indoor heat exchanger 9, the outdoor heat exchanger 23, and the water heat exchanger 31, Discharged as a gas refrigerant.
A discharge temperature sensor 39 for detecting the temperature of the discharged refrigerant and a discharge pressure sensor 41 for detecting the pressure are arranged on the discharge side of the compressor 17, and the temperature of the refrigerant sucked is detected on the suction side. An intake temperature sensor 43 and an intake pressure sensor 45 for detecting pressure are arranged.
In the present embodiment, the description is applied to an embodiment using two compressors 17.

  The oil separator 19 is disposed between the compressor 17 and the four-way valve 21, and is provided to separate the lubricating oil of the compressor 17 contained in the refrigerant discharged from the compressor 17 and return it to the compressor 17. It has been. Specifically, it is composed of two substantially cylindrical oil separation portions into which refrigerant discharged from each compressor 17 is introduced, and an oil storage portion disposed below the two oil separation portions. A heater 47 that controls the temperature of the separated lubricating oil is disposed in the oil reservoir. A supply circuit that supplies the separated lubricating oil to the compressor 17 is disposed between the oil reservoir of the oil separator 19 and the compressor 17.

  The four-way valve 21 is a flow path switching valve that is arranged on the downstream side of the oil separator 19 and switches the flow of the refrigerant, and is provided with four ports D, C, S, and E through which the refrigerant flows in and out. Port D is connected to the discharge side of the compressor 17, port C is connected to the outdoor heat exchanger 23, port S is connected to the suction side of the compressor 17, and port E is connected to the indoor heat exchanger 9.

The outdoor heat exchanger 23 functions as a condenser that releases heat to the outside air during the cooling operation and condenses the high-temperature and high-pressure gas refrigerant, and functions as an evaporator that draws heat from the outside air and evaporates the low-temperature and low-pressure refrigerant during the heating operation. The outdoor heat exchanger 23 includes an outdoor fan 24 that blows outside air to the heat exchanger portion. The outdoor heat exchanger 23 is provided with temperature sensors 15 at two locations for detecting the gas phase and liquid phase refrigerant temperatures.
In the present embodiment, the description is applied to an embodiment in which two outdoor heat exchangers 23 are used.

The receiver 27 traps the gas refrigerant contained in the refrigerant flowing out of the outdoor heat exchanger 23 or the indoor heat exchanger 9 and supplies only the liquid refrigerant to the indoor heat exchanger 9 or the outdoor heat exchanger 23.
An outdoor expansion valve 25 and a check valve 33 are arranged in parallel between the outdoor heat exchanger 23 and the receiver 27, and strainers 13 are provided upstream and downstream of the outdoor expansion valve 25 and the check valve 33. Has been placed. The check valve 33 is arranged so that the refrigerant flows from the outdoor heat exchanger 23 toward the receiver 27.

The supercooling coil 29 is disposed in a refrigerant circuit that connects the receiver 27 and the indoor unit 3. The subcooling coil 29 is provided with a refrigerant pipe that divides a part of the refrigerant flowing between the receiver 27 and the subcooling coil 29 and leads it to the subcooling coil 29. The refrigerant pipe is connected to the strainer 13 and the pressure of the refrigerant. A supercooling expansion valve (cooling restrictor) 49 for reducing and expanding the pressure is disposed. Part of the refrigerant that has passed through the supercooling coil 29 is guided to a refrigerant circuit that connects the four-way valve 21 and the compressor 17.
The supercooling coil 29 is provided to send the refrigerant cooled to the temperature required for the indoor unit 3 during the cooling operation. That is, the refrigerant sent to the indoor unit 3 is further cooled by the low-temperature refrigerant formed by the supercooling expansion valve 49 (the degree of supercooling is increased). Therefore, even when the arrangement position of the indoor unit 3 is away from the outdoor unit 5 and the pipe pressure loss in the main refrigerant pipe 7a is large, the refrigerant state at the inlet of the expansion valve of the indoor unit 3 can be maintained in the liquid phase, and appropriate cooling Ability can be gained. Moreover, generation | occurrence | production of a refrigerant | coolant flow noise etc. can also be suppressed.

The water heat exchanger 31 is arranged in a refrigerant pipe that branches from a refrigerant circuit that connects the outdoor heat exchanger 23 and the receiver 27 and merges with a refrigerant circuit that connects the four-way valve 21 and the compressor 17. On the side, a strainer 13 and a water heat exchanger expansion valve (heating restrictor) 51 for reducing and expanding the pressure of the refrigerant are arranged. Moreover, it arrange | positions so that the engine cooling water of the gas engine 53 mentioned later may circulate in the water heat exchanger 31. FIG.
The water heat exchanger 31 is provided in order to cause the refrigerant to recover the heat of engine cooling water described later. That is, during the heating operation, the refrigerant does not rely only on heat exchange in the outdoor heat exchanger 23, but also recovers exhaust heat from the engine coolant of the gas engine 53, thereby further improving the efficiency of the heating operation. it can. Further, even during the cooling operation, when the operation load of the indoor unit 3 is very small with low outside air, it is possible to maintain an appropriate high and low pressure by utilizing the water heat exchanger 31 as an evaporator.

On the other hand, in addition to the cooling water system 55 and the fuel intake system 57, the gas engine unit is provided with a combustion gas exhaust system and an engine oil system (both not shown) centering on the gas engine 53.
The gas engine 53 drives the compressor 17 installed in the refrigerant circuit via a shaft or a belt.

The cooling water system 55 includes a water pump 59, a reservoir tank 61, a radiator 63, and the like, and an engine cooling water (cooling medium) that circulates a circuit (indicated by a broken line in the figure) configured by connecting these with piping. This is a system for cooling the gas engine 53.
The water pump 59 is arranged to circulate the cooling water of the gas engine 53, and the reservoir tank 61 temporarily stores an excess amount of the cooling water that circulates in this circuit, or lacks the cooling water that circulates in the circuit. When arranged to supply cooling water. The radiator 63 is disposed in the vicinity of the outdoor heat exchanger 23 in order to release the exhaust heat taken by the engine cooling water from the gas engine 53.

The cooling water system 55 is provided with an exhaust gas heat exchanger 65 in addition to the configuration described above. The exhaust gas heat exchanger 65 is for recovering the heat of the exhaust gas discharged from the gas engine 53 into the engine cooling water. Further, the water heat exchanger 31 described above is disposed in the cooling water system 55 and is disposed so as to extend over both the refrigerant circuit section and the cooling water system 55.
Therefore, the engine cooling water not only takes heat from the gas engine 53 but also recovers heat from the exhaust gas and gives the recovered heat to the refrigerant via the water heat exchanger 31. .
The flow rate control of the engine coolant in the coolant system 55 is performed by two flow rate control valves 67A and 67B.

  The fuel intake system 57 is a system for supplying city gas such as liquefied natural gas (LNG) as gas fuel to the gas engine 53, and is provided with a fuel gas valve 69 for adjusting the supply amount of gas fuel. The fuel gas supplied from the fuel intake system 57 to the gas engine 53 is mixed with air sucked from an intake hole (not shown) of the gas engine 53 and then supplied to the combustion chamber of the gas engine 53.

Next, regarding the GHP 1 configured as described above, the operation during each operation of cooling and heating the room will be described.
First, the heating operation will be described based on FIGS. 5 and 6. In addition, the open / closed state of each valve is black, the illustrated valves are closed, and the flow directions of the refrigerant and the engine cooling water are indicated by arrows. In FIG. 1, the refrigerant flow direction during heating operation is indicated by a solid arrow, and the refrigerant flow direction during cooling operation described later is indicated by a dashed arrow.

  When the heating operation is selected, the four-way valve 21 of the refrigerant circuit unit is switched, the ports D / E and the ports C / S are communicated, and the discharge side of the compressor 17 and the indoor heat exchanger 9 are connected. Is done. In addition, the outdoor expansion valve 25 and the water heat exchanger expansion valve 51 are controlled by the control unit 37. The indoor electronic expansion valve 11 is controlled by a control unit (not shown) installed in the indoor unit 3.

First, the high-temperature and high-pressure gas refrigerant discharged from the compressor 17 flows into the oil separator 19 and the lubricating oil contained in the gas refrigerant is separated. The gas refrigerant from which the lubricating oil has been separated flows from the port D to the port E of the four-way valve 21 and flows into the indoor heat exchanger 9. The gas refrigerant is condensed and liquefied in the indoor heat exchanger 9 by releasing heat into the room air. The room air is warmed by absorbing heat from the gas refrigerant. The liquefied refrigerant passes through the indoor electronic expansion valve 11 and the supercooling coil 29 and flows into the receiver 27. The refrigerant is gas-liquid separated in the receiver 27, and only the liquid refrigerant flows out of the receiver 27.
A part of the liquid refrigerant flowing out from the receiver 27 flows into the outdoor heat exchanger 23 through the outdoor expansion valve 25. The remaining refrigerant flows into the water heat exchanger 31 through the water heat exchanger expansion valve 51.

The refrigerant flowing into the outdoor heat exchanger 23 is decompressed in the process of passing through the outdoor expansion valve 25, and becomes a low-temperature and low-pressure liquid refrigerant. In the outdoor heat exchanger 23, the low-temperature and low-pressure liquid refrigerant takes heat from the outside air and the like, and evaporates and vaporizes to become a gas refrigerant.
The refrigerant flowing into the water heat exchanger 31 is reduced in pressure in the process of passing through the water heat exchanger expansion valve 51 to become a low-temperature and low-pressure liquid refrigerant. In the water heat exchanger 31, the low-temperature and low-pressure liquid refrigerant takes heat from the engine cooling water and evaporates and vaporizes to become a gas refrigerant.

The gas refrigerant evaporated in the outdoor heat exchanger 23 flows from the port C of the four-way valve 21 through the port S to the suction port of the compressor 17. On the other hand, the gas refrigerant evaporated in the water heat exchanger 31 similarly flows into the refrigerant pipe connecting the port S of the four-way valve 21 and the suction port of the compressor 17.
The gas refrigerant sucked into the compressor 17 in this way is compressed by the compressor 17 to become a high-temperature and high-pressure gas refrigerant and is discharged toward the oil separator 19 again. Thereafter, the same process is repeated.

Next, the cooling operation will be described based on FIGS. 5 and 7.
When the cooling operation is selected, the ports D / C and the ports E / S of the four-way valve 21 communicate with each other, so that the discharge side of the compressor 17 and the outdoor heat exchanger 23 are connected.
In addition, the supercooling expansion valve 49 and the water heat exchanger expansion valve 51 are controlled by the control unit 37, and the outdoor expansion valve 25 is fully opened. The indoor electronic expansion valve 11 is controlled by a control unit (not shown) installed in the indoor unit 3.

First, the high-temperature and high-pressure gas refrigerant discharged from the compressor 17 is separated from the lubricating oil by the oil separator 19, passes through the four-way valve 21, and flows into the outdoor heat exchanger 23. In the outdoor heat exchanger 23, the gas refrigerant releases heat, condenses and liquefies, and becomes a liquid refrigerant. The liquid refrigerant that has flowed out of the outdoor heat exchanger 23 passes through the check valve 33 and flows into the receiver 27, is separated into gas and liquid, and only the liquid refrigerant flows out of the receiver 27.
A part of the liquid refrigerant flowing out from the receiver 27 flows into the indoor heat exchanger 9 through the supercooling coil 29 and the indoor electronic expansion valve 11. The remaining refrigerant flows into the supercooling coil 29 through the supercooling expansion valve 49. When the cooling load is very small, part of the refrigerant flowing out of the outdoor heat exchanger 23 passes through the water heat exchanger 31 via the water heat exchanger expansion valve 51, and the low-temperature and low-pressure liquid refrigerant is cooled by the engine. Heat is taken away from water, evaporated and vaporized to become a gas refrigerant to secure heat absorption and maintain an appropriate operating point.

In the process of passing through the supercooling coil 29, the refrigerant flowing into the indoor heat exchanger 9 is deprived of heat by the low-temperature and low-pressure liquid refrigerant that has passed through the subcooling expansion valve 49 described later. After that, the pressure is reduced in the process of passing through the indoor electronic expansion valve 11 to become a low-temperature and low-pressure liquid refrigerant. In the indoor heat exchanger 9, the low-temperature and low-pressure liquid refrigerant takes heat from the room air and evaporates and vaporizes to become a gas refrigerant.
The refrigerant flowing into the supercooling coil 29 is decompressed in the process of passing through the supercooling expansion valve 49, and becomes a low-temperature and low-pressure liquid refrigerant. This liquid refrigerant takes heat from the liquid refrigerant flowing into the indoor heat exchanger 9 described above in the supercooling coil 29, and is evaporated and vaporized to become a gas refrigerant.

The gas refrigerant evaporated in the indoor heat exchanger 9 flows from the port E of the four-way valve 21 through the port S to the suction port of the compressor 17. On the other hand, the gas refrigerant evaporated in the supercooling coil 29 similarly flows into the refrigerant pipe connecting the port S of the four-way valve 21 and the suction port of the compressor 17.
The gas refrigerant sucked into the compressor 17 in this way becomes a high-temperature and high-pressure gas refrigerant compressed by the compressor 17 and is discharged again toward the oil separator 19, and thereafter the same process is repeated.

As described above, in the GHP 1 provided with the multi-combination outdoor unit that connects and uses the two outdoor unit units 5 and 5, the number of the outdoor unit units 5 that are operated increases as the operating load increases. The operation is changed to two-unit operation. Below, the operation control which changes the outdoor unit 5 from 1 unit operation to 2 unit operation is demonstrated based on FIG.1 and FIG.2.
FIGS. 1A to 1C show changes in the refrigerant circulation amount that changes according to the operation load in response to the operation control of the present invention. FIG. 1A shows the refrigerant circulation of the entire GHP 1 (the entire apparatus). (B) is the refrigerant circulation amount of the outdoor unit (continuous operation outdoor unit) 5 that is continuously operated from one unit operation to two units operation, and (c) is the outdoor unit unit that is operated at the start of the two unit operation. (Additional cab outdoor unit) 5 refrigerant circulation amount. In the following description, it is assumed that the two compressors 17 installed in the outdoor unit 5 are driven by the same gas engine 53 at the same rotational speed, and therefore the refrigerant circulation amount is the rotation of the compressor 17. Or the number of revolutions of the gas engine 53.

The operation control shown in FIG. 1A includes a small / medium amount refrigerant operation control region in which one outdoor unit 5 is operated, and two units immediately after the outdoor unit 5 is changed from one to two units. An operation transition area and a refrigerant circulation amount identical control area after the two-unit operation transition area are provided, and the refrigerant circulation amount is increased substantially continuously as the demand for the operation load (air conditioning load) increases.
The first small / medium amount refrigerant operation region is a region in which one outdoor unit 5 is operated to cover the refrigerant circulation amount of GHP 1 from the minimum circulation amount to the allowable circulation amount. In this operation region, as shown in FIG. 1 (b), when one outdoor unit 5 is activated, the rotation speed of the compressor 17 rises to a predetermined low speed rotation speed, and the refrigerant circulation amount is reduced from zero. Slightly increase continuously. Thereafter, the operation of the compressor 17 enters a compressor protection start region in which the increase in the rotational speed is restricted for a predetermined time. In this compressor protection start region, the rotational speed of the compressor 17 is maintained at a predetermined low speed, so that the refrigerant circulation amount does not fluctuate even if the operating load requirement is increased, and is maintained at a relatively small constant value. Is done.

When the compressor protection start region ends, the demand for the operating load increases to increase the rotational speed of the compressor 17 and increase the refrigerant circulation amount to the allowable circulation amount. The allowable circulation amount is set to a point where the continuity is easily obtained from the refrigerant circulation amount 0 as the outdoor unit 5, but the compressor 17 is preferably used to supply the refrigerant over a wide range as much as possible with one outdoor unit 5. Set to a point close to the maximum permissible rotation speed.
In addition, the point of the above-mentioned allowable circulation amount is set by selecting a value that does not immediately return to the single operation even if the operation load decreases after the operation of the outdoor unit 5 to be described later is changed. It is preferable to do.
In addition, the point of the above-mentioned allowable circulation amount is that the second outdoor unit 5 is continuously operated even in a situation where the operation cannot be performed at a high speed when the lubricating oil is dissolved in the refrigerant and becomes highly diluted. It is preferable to set the value so that it can be activated.

The two-unit operation transition region is selected when the refrigerant circulation amount is still insufficient even if the refrigerant circulation amount is increased to the allowable circulation amount in the small and medium amount refrigerant operation control region described above. This operation region is performed when the additional operation of the outdoor unit 5 that is in a suspended state due to one unit operation is started, and includes a complementary control region and a maximum efficiency point fixed region.
The supplementary control region is an outdoor unit (hereinafter referred to as “continuous operation outdoor unit”) that is continuously operated from the small and medium amount refrigerant operation control region (hereinafter referred to as “continuous operation outdoor unit”). This is an area in which operation control is performed so as to maintain the continuity of the refrigerant circulation amount during startup of the “additional operation outdoor unit”. That is, this complementary control area is operation control that is performed immediately after the additional operation outdoor unit is activated, and at the time of activation of the additional operation outdoor unit in the same manner as the activation of the first unit (continuous operation outdoor unit) described above. In the vicinity of the compressor protection start area that is also implemented, by controlling the continuous circulation outdoor unit side to compensate for the discontinuity of the refrigerant circulation amount that occurs on the additional operation outdoor unit side, It keeps continuity.

Here, the transition of the refrigerant circulation amount in the above-described complementary control region will be specifically described with reference to FIG.
When the additional cab outdoor unit is started in FIG. 1 (c), the refrigerant circulation amount continuously increases slightly to the compressor protection start region. Simultaneously with this increase in the amount of refrigerant circulation, the continuous operation outdoor unit appropriately reduces the refrigerant circulation amount from the allowable circulation amount according to the increasing speed on the additional operation outdoor unit side, and the total refrigerant circulation amount supplied from both outdoor unit units The value is adjusted so as to continuously increase from the small and medium amount refrigerant operation control region.
Next, when the additional operation outdoor unit enters the compressor protection start region, the refrigerant circulation amount on the continuous operation outdoor unit side is increased to compensate for the refrigerant circulation amount on the additional operation outdoor unit side that is maintained at a constant amount for a predetermined time. The total value is adjusted so as to continuously increase from the small / medium amount refrigerant operation control region.
Finally, after the compressor protection start area for the additional oper- ating outdoor unit is completed, the refrigerant circulation amount on the additional operation outdoor unit side is increased and the refrigerant circulation amount on the continuous operation outdoor unit side is decreased to reduce the refrigerant circulation amount. Is adjusted so as to continuously increase from the small and medium amount refrigerant operation control region. And if the refrigerant | coolant circulation amount by the side of a continuous driving | running | working outdoor unit decreases to the value corresponding to a maximum efficiency point, a complement control area | region will be complete | finished at this time and it will transfer to a maximum efficiency point fixed area | region.

  The maximum efficiency point fixed area controls the operation so as to maintain the continuity of the refrigerant circulation rate by fixing the continuous operation outdoor unit to the most efficient operating condition and increasing only the refrigerant circulation rate of the additional outdoor unit. It is an area. Therefore, in this maximum efficiency fixed region, the additional operation outdoor unit is operated until the shortage of the continuous operation outdoor unit in which the refrigerant circulation amount is fixed is reached and the maximum efficiency point is reached. That is, the operation control in the maximum efficiency fixed region is continued until both the continuous operation outdoor unit and the additional operation outdoor unit reach the maximum efficiency point, and the transition of the refrigerant circulation amount is adjusted by adjusting the additional operation outdoor unit side. It can be increased continuously from the two-unit operation transition region.

  In the same control range for the refrigerant circulation amount, the refrigerant circulation amount of the continuous operation outdoor unit and the additional operation outdoor unit that have reached the maximum efficiency point are set to be the same, and continuously from the two-unit operation transition region as the operation load increases. This is operation control for increasing the total value of the refrigerant circulation amount to the upper limit. Therefore, although it becomes an operation region where the total value of the refrigerant circulation amount is the largest, since the operation control is performed so that the gas engine 53 of the continuous operation outdoor unit and the additional operation outdoor unit have the same rotation speed, A highly reliable operation is possible by preventing deviations in the refrigerant circulation amount and the lubricating oil circulation amount.

Here, the selection switching control of the above-described small / medium amount refrigerant operation control region by single unit operation, two unit operation transition region by two outdoor unit operation, and the same refrigerant circulation amount control region is based on the flowchart of FIG. explain.
When the operation load becomes “loaded” in the first step S1, the operation proceeds to the next step S2 where one outdoor unit is operated, and the above-described operation control in the small and medium quantity refrigerant operation control region is performed. That is, the engine speed is controlled in accordance with the operating load within the range of the refrigerant circulation amount 0 to the allowable circulation amount. Since this single outdoor unit operation is an operation region in which the refrigerant circulation amount is relatively small, that is, the medium circulation amount, load determination is sequentially performed in the next step S3 during the operation.

As a result of the load determination, when the refrigerant circulation amount is insufficient with respect to the operation load, the process proceeds to the next step S4 and the two outdoor unit units are operated. In this case, the operation of the two outdoor unit units is in the above-described two-unit operation transition region, so that the refrigerant circulation amount can be continuously increased from the small / medium amount refrigerant operation control region.
On the other hand, when it is determined by the load determination in step S3 that the refrigerant circulation amount is balanced or excessive with respect to the operation load, the operation returns to the previous step S2 and the single outdoor unit is operated. At this time, if the refrigerant circulation amount is balanced, the rotational speed of the gas engine 53 is maintained, and if it is determined that the refrigerant circulation amount is excessive, the engine rotational speed is decreased.

The refrigerant circulation amount continuously increases even in the two-unit outdoor unit operation in the two-unit operation transition region described above, but load determination is sequentially performed in the next step S5 even during the operation.
As a result of the load determination, when the refrigerant circulation amount is insufficient with respect to the operation load, the process proceeds to the next step S6 and the two outdoor unit units are operated. In this case, since the operation of the two outdoor unit units is in the above-described refrigerant circulation amount control region, the operation control is shifted from the two-unit operation transition region to the operation region in which the refrigerant circulation amount is the largest continuously.
On the other hand, when it is determined by the load determination in step S5 that the refrigerant circulation amount is balanced with respect to the operation load, the operation returns to the previous step S4 to continue the operation of the two outdoor units in the two-unit operation transition region. . If it is determined by the load determination in step S5 that the refrigerant circulation amount is excessive with respect to the operation load, the flow returns to the previous step S2 to return to the single outdoor unit operation.

The refrigerant circulation amount continuously increases to the upper limit even in the above-described operation of the two outdoor units in the same refrigerant circulation amount control region, but load determination is sequentially performed in the next step S7 even during the operation.
As a result of the load determination, when it is determined that the refrigerant circulation amount is balanced or insufficient with respect to the operation load, the operation returns to the previous step S6 to continue the operation of the two outdoor units in the refrigerant circulation amount identical control region. To do. Further, when it is determined by the load determination in step S7 that the refrigerant circulation amount is excessive with respect to the operation load, the flow returns to the previous step S4 to perform the two outdoor unit operation in the two-unit operation transition region.
As described above, the GHP 1 described above performs sequential load determination in each control region of single outdoor unit operation and two outdoor unit operations, and the result of determination that the refrigerant circulation amount is insufficient, balanced or excessive with respect to the operational load. Accordingly, the operation control region can be continued or changed, and the refrigerant circulation amount can be continuously changed with respect to the operation load.

Further, in the above-described GHP1, when the demand for the refrigerant circulation amount increases after the completion of the complementary control region, the continuous operation outdoor unit that is continuously operated from the small and medium amount refrigerant operation region is operated while being fixed at the highest efficiency point. Control becomes stable and efficient operation is possible. Furthermore, since the control region where only one gas engine 53 is operated is wide, the efficiency is improved in the medium refrigerant amount region.
In FIG. 4, the horizontal axis indicates the capacity of GHP 1 (the maximum capacity is 100% and is dimensionless), and the vertical axis indicates the efficiency COP (COP ratio with the maximum COP as a reference value). In this case, the outdoor unit 5 has two compressors 17 capable of capacity control, and capacity control from partial load operation (P) to full load operation (F) is possible for each compressor 17. In addition, the operation of one compressor 17 can be stopped by a switching operation of a clutch or the like.

In such operation of GHP1, in order to increase the capacity as the operating load increases, the efficiency COP in the case of partial load operation of one compressor 17 in the continuous operation outdoor unit is (a), and the compressor 17 is 1 The efficiency COP in the case of the stand full load operation is shown in (b), the efficiency COP in the case where one of the compressors 17 is fixed to the full load operation and the other one is in the partial load operation is shown in (c), and the compressor 17 (D) shows the efficiency COP when both are fully loaded.
In addition, the efficiency COP when the two compressors 17 of the continuous operation outdoor unit are fixed to the full load operation and the single compressor 17 of the additional operation outdoor unit is the partial load operation is (e), and the compressor 17 is The efficiency COP in the case of one full load operation is (f), the efficiency COP in the case of fixing one of the compressors 17 to the full load operation and the other partial load operation is (g), and the compressor 17 (H) shows the efficiency COP when both are fully loaded.
That is, the graph of FIG. 3 shows the efficiency COP of the operation control obtained by adding the capacity control for each compressor 17 to the operation control of the GHP 1 described above.

On the other hand, the graph shown in FIG. 4 shows a similar graph with respect to the prior art based on operating both gas engines 53 of the outdoor unit 5 having the same performance at the same rotational speed.
In this graph, in order to increase the capacity as the operating load increases, the efficiency COP when performing partial load operation of one compressor 17 in the continuous operation outdoor unit is (a), and one compressor 17 is fully loaded. The efficiency COP is shown in (b), and the efficiency COP in the case where both of the two compressors 17 of the outdoor unit are fully loaded are shown in (f). These operation modes are shown in FIG. Same as a), (b), (h).

However, in the middle region of the capacity, consideration is given to the same refrigerant circulation amount of the continuous operation outdoor unit and the additional operation outdoor unit, so that the operation mode is different from the operation mode of FIG. 3 described above. The efficiency COP when one compressor of the continuous operation outdoor unit is fully loaded and the partial operation of the compressor of the additional operation outdoor unit is (c), respectively, in the continuous operation outdoor unit and the additional operation outdoor unit. The efficiency COP when one compressor 17 is fully loaded is shown in (d), and the efficiency COP when the compressors 17 of both outdoor unit units are one full load and one partial load, respectively. It is shown in (e).
That is, in (c) to (e) showing the intermediate region, the two gas engines 53 are both operated.

  Therefore, comparing the efficiency COPs in FIGS. 3 and 4, the refrigerant circulation amount in which the gas engine 53 requires only one operation mode, that is, the operation mode similar to the conventional technology shown in FIG. In the middle (c) to (g) sandwiched between (a) and (b) and a large amount of refrigerant circulation (h), the improvement of the efficiency COP is remarkable. Therefore, the operation control in which the number of operating gas engines 53 is as wide as possible and the transition of the refrigerant circulation amount is continuous is particularly improved in the region where the refrigerant circulation amount is intermediate.

As described above, according to the GHP 1 of the present invention, the range in which the outdoor unit 5 can be operated by one unit has been expanded to the maximum, so that the maintenance period and product life of the entire GHP 1 that are particularly affected by the operating time of the gas engine 53. Can be extended. Further, since the range in which the outdoor unit 5 is operated as a single unit in the operation range of small to medium capacity in which the bias of the refrigerant and the lubricating oil is relatively difficult to occur, the rotational speed range that is disadvantageous in terms of efficiency of the gas engine 53 is achieved. The effect of improving the efficiency (COP) by reducing the ratio of using the.
In addition, the continuous operation outdoor unit is fixed at the highest efficiency point, and the additional operation outdoor unit is operated to compensate for the shortage of the refrigerant circulation amount supplied by the continuous operation outdoor unit. In addition, the GHP 1 as a whole can be operated efficiently.

As a result, the GHP 1 equipped with the multi-combination machine of the present invention has the remarkable effect of improving the efficiency of the entire apparatus and extending the maintenance period and product life.
In the above-described embodiment, the configuration in which two outdoor unit units 5 are connected has been described. However, in the case of three or more units, the number of operating units may be added sequentially by the same control.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

As one embodiment of the gas heat pump type air conditioner according to the present invention, the change of the refrigerant circulation amount that changes according to the operation control region and the operation load is shown, (a) shows the change of the entire device, (b). (C) is a graph which shows transition of an additional cab outdoor unit. In the gas heat pump type air conditioner of the present invention, the operation related to the selective switching control of the small / medium amount refrigerant operation control region by the single outdoor unit operation, the two unit operation transition region by the two outdoor unit operation, and the refrigerant circulation amount identical control region. It is a flowchart which shows control. It is the graph which showed efficiency COP on the vertical axis | shaft by making the horizontal axis the capacity | capacitance (W) about the gas heat pump type air conditioner of this invention. It is the graph which showed efficiency COP on the vertical axis | shaft about the capacity | capacitance (W) of the horizontal axis about the gas heat pump type air conditioner of a prior art. It is a figure which shows the refrigerant | coolant flow at the time of the whole structure and an air conditioning operation as an example of the gas heat pump type air conditioner (GHP) which concerns on this invention. It is a figure which shows the structural example of the outdoor unit in the gas heat pump type air conditioning apparatus of FIG. 5, and the refrigerant | coolant flow at the time of heating operation. It is a figure which shows the structural example of the outdoor unit in the gas heat pump type air conditioning apparatus of FIG. 5, and the refrigerant | coolant flow at the time of air_conditionaing | cooling operation.

Explanation of symbols

1 Gas heat pump type air conditioner (air conditioner)
3 Indoor unit 5 Outdoor unit 9 Indoor heat exchanger (heat absorber, radiator)
11 Indoor electronic expansion valve (throttle part)
17 Compressor 21 Four-way valve (switching part)
23 Outdoor heat exchanger (heat absorber, radiator)
25 Outdoor expansion valve (throttle part)
29 Supercooling coil (cooling heat exchanger)
31 Water heat exchanger (heat exchanger for heating)
37 Control part 49 Supercooling expansion valve (cooling throttle part)
51 Expansion valve for water heat exchanger (throttle for heating)

Claims (3)

In a gas heat pump type air conditioner equipped with a multi-combination outdoor unit that connects and uses a plurality of outdoor unit units,
A small-medium amount refrigerant operation control region that operates one of the outdoor unit and covers the refrigerant circulation amount from the minimum circulation amount to the allowable circulation amount;
An outdoor unit that is implemented when the request for the refrigerant circulation amount exceeds the allowable circulation amount and starts the additional operation of the outdoor unit, and the outdoor unit that is continuously operated from the small and medium amount refrigerant operation control region additionally operates. A gas heat pump type air conditioner characterized in that a supplementary control region that is operated and controlled so as to maintain the continuity of the refrigerant circulation amount during startup of the unit is provided.   2. The outdoor unit that is continuously operated from the small and medium amount refrigerant operation region is operated at a maximum efficiency point when the demand for the refrigerant circulation amount increases after the completion of the complementary control region. The gas heat pump type air conditioning apparatus described.   After the additional operated outdoor unit reaches the maximum efficiency point, the refrigerant circulation amount of all the outdoor unit operated is set to the same amount when the demand for the refrigerant circulation amount further increases. The gas heat pump type air conditioner according to claim 2.

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