JP2007107859A - Gas heat pump type air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent liquid refrigerant accumulation caused on a stopping outdoor unit side when an outside air temperature is low in a GHP having a multi-combination units equipped with no accumulator. <P>SOLUTION: This gas heat pump type air conditioner is provided with multi-combination outdoor units consisting of two outdoor units 5 and 5 connected together in use. During a cooling operation in which at least one of the outdoor units 5 is operated, if there is the outdoor unit 5 not operated continuously for a predetermined time or more and a time period, over which a temperature difference between a temperature detected by a suction pipe temperature sensor in the stopping unit and a suction pressure saturation temperature is lower than a predetermined value, is continued for a predetermined time while a time period, over which a temperature detected by a machine chamber temperature sensor in the stopping unit is lower than a comparison temperature found by adding a predetermined value to the suction pressure saturation temperature, is continued for a predetermined time or more, rotation control is carried out for exchanging operation and nonoperation of the outdoor units. <P>COPYRIGHT: (C)2007,JPO&INPIT

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, and is particularly suitable for a multi-combination outdoor unit that combines outdoor unit units not provided with an accumulator. Technology.

Conventionally, a refrigerant circuit having elements such as an indoor heat exchanger, a compressor, an outdoor heat exchanger, and a throttle mechanism is used, and a compressor is driven by a gas engine that is driven by city gas or the like as a fuel. A gas heat pump type air conditioner (hereinafter referred to as “GHP”) that performs an air conditioning operation such as 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.
In such a GHP, there are those equipped with a multi-combination outdoor unit that connects and uses a plurality of outdoor unit units. For example, when one outdoor unit unit is operated independently according to conditions such as an air conditioning load. There is also.

In a multi-type air conditioner in which one outdoor unit is equipped with a variable capacity compressor and a constant capacity compressor, and each other outdoor unit is equipped with a plurality of constant capacity compressors, at least one outdoor unit With the constant unit compressor operating time as the outdoor unit operation time, when the load increases, operate one of the constant capacity type compressors in order from the outdoor unit with the shortest operation integration time, and according to the further increase in load Operate the remaining constant capacity compressors in the order of the same outdoor units as above, and rotate the constant capacity compressors of each indoor unit so that they enter the operation in ascending order of accumulated operation time. In addition, it has been proposed to make the operation time of each constant capacity compressor uniform. (For example, see Patent Document 1)
JP 2001-41528 A

By the way, in GHP provided with the multi combination outdoor unit, the following problems occur when the single outdoor unit is operated according to the operating conditions.
(1) When the cooling operation is performed at a low outside air temperature, the liquid refrigerant condenses and accumulates in the suction pipe of the outdoor unit that is stopped, resulting in an excessive liquid back at the next start-up. .
(2) When heating operation is performed at a low outdoor temperature, liquid refrigerant condenses and accumulates in the outdoor heat exchanger (air heat exchanger) of the outdoor unit that is stopped. It becomes an excessive liquid back. Moreover, when liquid refrigerant condenses in the outdoor heat exchanger, gas-low operation is insufficient in which the amount of refrigerant circulating through the refrigerant circuit in operation is insufficient, and there is a concern that air conditioning capability may be reduced.

(3) A difference occurs in the operation time for each of the plurality of outdoor unit units, resulting in non-uniformity. In the case of GHP, since a gas engine is used as a drive source for the compressor, maintenance is required every time a predetermined operation time (for example, about 10,000 hours) elapses.
However, if the operation time is not uniform, the maintenance execution timing differs for each outdoor unit, so the number of GHP maintenance increases and the operation stop time increases. Further, when all the maintenances are performed at the same time as the first maintenance time, although the GHP operation stop time is reduced, an outdoor unit that performs maintenance before reaching the predetermined operation time is generated. .
From the above (1) and (2), in the GHP equipped with the multi-combination outdoor unit, it is desired to prevent liquid refrigerant from accumulating on the side of the outdoor unit that is stopped at a low outdoor temperature. Further, from the above (3), in the GHP provided with the multi-combination outdoor unit, it is desired that the operation time for each outdoor unit is made uniform, and the maintenance time required after a predetermined operation time elapses.

In the case of an air conditioner equipped with an accumulator, the accumulator becomes a large buffer even if the air conditioner accumulates in the suction pipe or the air heat exchanger, so there is a high margin for liquid back. However, when there is an accumulator, the suction pressure loss is large, and there are many problems such as once the refrigerant has accumulated, it is difficult to pass through, and this model was solved by accumulator-less.
The present invention has been made in view of the above circumstances, and the object of the present invention is to generate on the outdoor unit side that is stopped at a low outdoor temperature in a GHP equipped with a multi-combination machine not provided with an accumulator. In addition to preventing the liquid refrigerant from accumulating, the operation time for each outdoor unit is made uniform so that the maintenance time required after a predetermined operation time elapses.

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,
During cooling operation in which at least one of the outdoor unit is operated, there is an outdoor unit that has been in a suspended state for a predetermined time or more, and the suction pipe temperature sensor detected temperature and the suction pressure saturation temperature of the suspended unit are When the state where the temperature difference is smaller than a predetermined value continues for a predetermined time or more, and the state where the temperature detected by the machine room temperature sensor of the pause unit is lower than the comparison temperature obtained by adding the predetermined value to the suction pressure saturation temperature, continues for a predetermined time or more. In addition, rotation control for exchanging operation and suspension of the outdoor unit is performed.

  According to such a gas heat pump type air conditioner, there is an outdoor unit that is in a suspended state continuously for a predetermined time or more during a cooling operation in which at least one of the outdoor unit is operated. The temperature difference between the temperature sensor detection temperature and the suction pressure saturation temperature is smaller than the predetermined value for a predetermined time or more, and the machine room temperature sensor detection temperature of the pause unit is higher than the comparison temperature obtained by adding the predetermined value to the suction pressure saturation temperature. Rotation control is performed to switch the operation and suspension of the outdoor unit when the low state continues for a predetermined time or longer. Therefore, when the cooling operation is performed at a low outdoor temperature, the outdoor unit that is stopped (pause) The liquid refrigerant can be prevented from condensing and collecting in the suction pipe of the unit.

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,
During the heating operation in which at least one of the outdoor unit is operated, there is an outdoor unit that is in a suspended state continuously for a predetermined time or more, and the temperature between the detected temperature of the outdoor temperature sensor and the suction pressure saturation temperature of the suspended unit The state where the difference is smaller than the predetermined value continues for a predetermined time or more, and the state where the temperature difference between the detected temperature of the outdoor heat exchanger liquid pipe temperature sensor of the pause unit and the suction pressure saturation temperature is smaller than the predetermined value is the predetermined time. When the operation is continued as described above, rotation control for exchanging operation and suspension of the outdoor unit is performed.

  According to such a gas heat pump type air conditioner, during heating operation in which at least one of the outdoor unit is operated, there is an outdoor unit that is in a suspended state continuously for a predetermined time or more, and the outdoor air temperature of the suspended unit The state where the temperature difference between the sensor detection temperature and the suction pressure saturation temperature is smaller than a predetermined value continues for a predetermined time or more, and the temperature difference between the detection temperature of the outdoor heat exchanger liquid pipe temperature sensor of the pause unit and the suction pressure saturation temperature Rotation control is performed to switch the operation and pause of the outdoor unit when the state is less than the predetermined value for a predetermined time or longer, so when heating operation is performed at low outdoor temperatures, the outdoor operation is stopped It is possible to prevent the liquid refrigerant from condensing and accumulating in the outdoor heat exchanger of the machine unit (pause unit).

  In the above invention, the operation time of the outdoor unit is compared, and when the operation time difference is larger than a predetermined value, it is preferable that rotation control is performed to replace the operation and suspension of the outdoor unit. The operation time for each of the plurality of outdoor unit units can be made substantially uniform.

  According to the above-described present invention, when the cooling operation and the heating operation are performed at a low outside air temperature, the rotation control for switching the operation and the suspension of the outdoor unit is performed when the control condition is satisfied. It is possible to prevent the liquid refrigerant from condensing and accumulating in the suction pipe of the outdoor unit (pause unit) or in the outdoor heat exchanger. For this reason, it is possible to prevent the liquid refrigerant accumulated when starting the pause unit from causing an excessive liquid back, and the liquid refrigerant can be condensed and accumulated in the outdoor heat exchanger during heating operation. Since there is not, the fall of the air-conditioning capability by gas low operation can also be prevented. Such an effect is particularly remarkable in a gas heat pump type air conditioner equipped with a multi-combination machine that uses an outdoor unit without an accumulator in combination.

In addition, when the operation time difference between the plurality of outdoor unit becomes larger than a predetermined value, rotation control is performed to switch the operation and suspension of the outdoor unit, so the operation time for each of the plurality of outdoor unit is reduced. It can be made substantially uniform, and the maintenance time of the outdoor unit can be made uniform.
Therefore, the gas heat pump type air conditioner of the present invention prevents liquid refrigerant from accumulating on the outdoor unit side that is stopped at a low outdoor temperature, and uniformizes the operation time for each outdoor unit. The remarkable effect that the maintenance time required after the operation time elapses is obtained.

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. 1 is a circuit diagram showing the overall configuration of a GHP according to the present invention.
The GHP (air conditioner) 1 includes one or a plurality of indoor unit units 3 that are disposed in a room to be air-conditioned, a plurality of outdoor unit units 5 that are disposed outdoors and have no accumulator, the indoor unit unit 3 and the outdoor unit A refrigerant circuit 7 that circulates refrigerant with the machine unit 5 is schematically configured. 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. 2, for example, the outdoor unit 5 is divided into two large components inside. The outdoor unit 5 is installed in a machine room indicated by a one-dot chain line in the figure, and a machine room temperature sensor 71 for detecting the temperature inside the machine room, and an outside air temperature sensor 73 for detecting the outside air temperature outside the machine room, It has.
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 for supplying 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 separated 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, Cooling capacity can be obtained. Moreover, generation | occurrence | production of a refrigerant | coolant flow noise etc. can 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 operating load of the indoor unit is low with low outside air, it is possible to maintain an appropriate high and low pressure by using it 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 with reference to FIGS. 1 and 2. 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. Further, the outdoor expansion valve 25, the water heat exchanger expansion valve 51, and the supercooling expansion valve 49 are controlled by the control unit 37. The indoor side electronic expansion valve 11 is controlled by a control unit installed in the indoor unit.

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. 1 and 3.
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 side electronic expansion valve 11 is controlled by a control unit installed in the indoor unit.

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 liquid refrigerant flowing out of the outdoor heat exchanger 23 passes through the water heat exchanger 31 through the expansion valve 51 for the water heat exchanger, and the low-temperature and low-pressure liquid refrigerant is converted into the engine. Heat is taken from the cooling water, evaporated and vaporized to become a gas refrigerant, ensuring the amount of heat absorption and maintaining 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.

Now, in the GHP 1 configured as described above, the operation of the multi-combination outdoor unit that uses the two outdoor unit units 5 and 5 connected to each other performs the control described below.
First, the rotation control that is performed during the cooling operation in which at least one of the plurality of outdoor unit units 5 is in operation and that switches the operation and suspension of the outdoor unit units 5 and 5 will be described.

This rotation control is performed by the control unit 37 when all of the first to fourth conditions described below are satisfied.
The first condition is that the GHP 1 is performing a cooling operation. That is, the outdoor heat exchanger 23 functions as a condenser (heat radiator).
The second condition is that there is an outdoor unit 5 that is in a resting state for a predetermined time ts (for example, about 5 minutes) or longer.

The third condition is that the temperature difference ΔT1 (ΔT1 = Ts−SST) between the suction pipe temperature sensor detected temperature Ts and the suction pressure saturation temperature SST of the outdoor unit (hereinafter referred to as “pause unit”) 5 in the dormant state. However, this is a case where a state (ΔT1 <Tx) smaller than a predetermined value Tx (for example, about 2 ° C.) is continued for a predetermined time ta (for example, about 5 minutes) or longer.
The suction pipe temperature sensor detection temperature Ts in this case is the temperature detected by the suction temperature sensor 43 installed in the suction pipe of the compressor 17 and is the refrigerant temperature of the suction pipe (low pressure part) in the refrigerant circuit 7.
The suction pressure saturation temperature SST is the refrigerant pressure detected by the suction pressure sensor (low pressure sensor) 45 installed in the suction pipe of the compressor 17, that is, the low pressure of the refrigerant circuit 7, similarly to the above-described suction pipe temperature sensor detection temperature Ts. It is a saturation temperature conversion value calculated by converting from the above.

The fourth condition is that the machine room temperature sensor detection temperature Tm of the pause unit 5 is lower than the comparison temperature Tα obtained by adding a predetermined value α (for example, about 5 ° C.) to the above-described suction pressure saturation temperature SST (SST <Tα). Is continued for a predetermined time tb (for example, about 5 minutes) or more.
The machine room temperature sensor detection temperature Tm is the temperature inside the machine room detected by the machine room temperature sensor 71.

That is, when all the first to fourth conditions are satisfied, the condensed liquid refrigerant such that the suction pipe for sucking the refrigerant into the compressor 17 of the pause unit 5 is in a temperature environment close to the refrigerant suction pressure saturation temperature SST. Therefore, the control unit 37 performs the above-described rotation control.
By this rotation control, the operation of the pause unit 5 is started before the liquid refrigerant is accumulated or in a state where the liquid refrigerant has started to be accumulated, so that the phenomenon that the liquid refrigerant accumulates in the suction pipe can be prevented. As a result, when the suspension unit 5 is started by rotation control, or when the suspension unit 5 is started next time, the amount of liquid refrigerant accumulated in the suction pipe is little or small. It is possible to prevent an excessive liquid back phenomenon of sucking the liquid refrigerant.

Next, a description will be given of rotation control that is performed during a heating operation in which at least one of the plurality of outdoor unit units 5 is operated, and that switches the operation and suspension of the outdoor unit units 5 and 5.
This rotation control is performed by the control unit 37 when all of the first to fourth conditions described below are satisfied.

The first condition is that the GHP 1 is performing the heating operation. That is, the outdoor heat exchanger 23 functions as an evaporator (heat absorber).
The second condition is that there is an outdoor unit 5 that is in a resting state for a predetermined time ts (for example, about 5 minutes) or longer. The predetermined time ts in this case is the same as that during the cooling operation described above, but is not particularly limited.

The third condition is that the temperature difference ΔT2 (ΔT2 = To−SST) between the outside air temperature sensor detected temperature To of the outdoor unit (hereinafter referred to as “pause unit”) 5 in the dormant state and the above-described suction pressure saturation temperature SST. ) Is smaller than a predetermined value Ty (for example, about 2 ° C.) (ΔT2 <Ty) for a predetermined time tc (for example, about 5 minutes) or longer.
In this case, the outside air temperature sensor detection temperature To is a temperature detected by the outside air temperature sensor 73 installed outside the machine room of the pause unit 5, and is a value obtained by measuring the outside air temperature at the place where the pause unit 5 is installed. is there.
The suction pressure saturation temperature SST is converted from the refrigerant pressure detected by the suction pressure sensor 45 installed in the suction pipe of the compressor 17, that is, the low pressure of the refrigerant circuit 7, in the same manner as the above-described suction pipe temperature sensor detection temperature Ts. This is a calculated saturated temperature conversion value.

The fourth condition is that the temperature detected by the outdoor heat exchanger liquid pipe temperature sensor of the pause unit 5, that is, the temperature sensor on the liquid phase side of the two temperature sensors 15 provided in the outdoor heat exchanger 23 ( The temperature difference ΔT3 (ΔT3 = Ti−SST) between the detected temperature Ti detected by the outdoor heat exchanger liquid pipe part temperature sensor) and the suction pressure saturation temperature SST described above is smaller than a predetermined value Tz (for example, about 2 ° C.) ( This is a case where the state ΔT3 <Tz) continues for a predetermined time td (for example, about 5 minutes) or longer. In this case, the temperature sensor 15 on the liquid phase side of the outdoor heat exchanger 23 is disposed on the refrigerant inlet side where liquid refrigerant is introduced from the outdoor expansion valve 25.
Since the illustrated outdoor unit 5 includes two sets of outdoor heat exchangers 23 and 23, the average value of the detected temperatures detected by the temperature sensor 15 provided on each liquid phase side is used as the outdoor heat exchanger. The detected temperature Ti detected by the liquid pipe temperature sensor may be used.

That is, when all of the first to fourth conditions are satisfied, the outdoor heat exchanger 23 of the pause unit 5 is likely to accumulate condensed liquid refrigerant, such as being in a temperature environment close to the refrigerant suction pressure saturation temperature SST, or Since it can be determined that the liquid refrigerant has started to accumulate, the controller 37 performs the rotation control described above.
By this rotation control, the operation of the pause unit 5 is started before the liquid refrigerant is accumulated or in a state where the liquid refrigerant has started to be accumulated, so that the phenomenon that the liquid refrigerant accumulates in the outdoor heat exchanger 23 can be prevented in advance. Can do. As a result, when the suspension unit 5 is started by rotation control, or when the suspension unit 5 is started next time, the amount of liquid refrigerant accumulated in the outdoor heat exchanger 23 is zero or small. In addition to preventing an excessive liquid back phenomenon in which a large amount of liquid refrigerant is sucked into 17, it is also possible to prevent gas-low operation in which the air conditioning performance deteriorates due to insufficient refrigerant.

Further, in the GHP 1 described above, the operation times of the two outdoor unit units 5 and 5 installed are compared, and when the operation time difference becomes larger than a predetermined value, the rotation control for switching the operation and the suspension of the outdoor unit is performed. The operation time of each outdoor unit 5 is made substantially uniform. This rotation control is performed by the control unit 37 in the same manner as the rotation control described above.
Hereinafter, rotation control for the purpose of equalizing the operation time will be described based on the flowchart of FIG.

First, when starting in step S1, it is determined in the next step S2 whether or not one outdoor unit 5 is in operation.
As a result, in the case of “YES” in which one outdoor unit 5 is in operation, the process proceeds to the next step S3 and the operation time of the outdoor unit 5 is confirmed. The operation time of the operation unit confirmed here is assumed to be t1, and the operation time of the suspension unit is assumed to be t2. The operating times t1 and t2 are accumulated and stored by means not shown provided in the control unit 37, for example.
On the other hand, when the determination in step S2 is “NO”, since the two outdoor unit units 5 and 5 are in operation, the process proceeds to step S10 and the following control ends.

  After confirming the operation times t1 and t2 in step S3, the process proceeds to the next step S4 to calculate the operation time difference Δt. That is, when the operation time difference Δt (Δt = t1−t2) obtained by subtracting the operation time t2 of the operation unit from the operation time t1 of the operation unit is “YES” greater than a predetermined time H (for example, about 500 hours) (Δt> H). Therefore, it is determined that rotation is necessary because the operation time difference Δt is large, and the process proceeds to the next step S5 to perform rotation control of the outdoor unit 5. In the rotation control in step S5, the operation unit is stopped and the operation of the suspension unit is started.

  After performing the rotation control in this way, the process proceeds to the next step S6 to calculate again the operation time difference Δt between the operation time t1 of the operation unit and the operation time t2 of the suspension unit. In this case, the operation unit and the suspension unit are stepped. It is replaced by the rotation control of S5. The operation time difference Δt thus calculated is compared with a predetermined time h (for example, about 128 hours). As a result, when the operation time difference Δt is “YES” smaller than the predetermined time h (Δt <h), it is determined that rotation is not necessary because the operation time difference Δt is small, and the process proceeds to step S2 described above. Continue to operate one unit.

  However, if the operation time difference Δt is “NO” greater than the predetermined time h in step S6 (Δt ≧ h), the process proceeds to step S7 to perform the rotation prohibition control, and then proceeds to the above-described step S2 and the outdoor One unit of machine unit 5 continues to operate. In addition, the rotation prohibition control in step S7 is performed continuously with the same unit until the difference in H time is resolved after the rotation with the H time difference, which is also desirable for the engine / comp. Therefore, the rotation is recognized when the difference is equal to or less than h hours.

In step S4 described above, when the operation time difference Δt is “NO”, which becomes smaller than the predetermined time H (Δt ≦ H), it is determined that rotation for equalizing the operation time difference Δt is unnecessary, and the next Proceed to step S8. In step S8, the rotation condition of the outdoor unit 5 is determined. That is, it is determined whether or not the first to fourth conditions for performing the rotation control are satisfied during the cooling operation and the heating operation described above.
As a result, if “YES” that satisfies the condition, the process proceeds to the next step S9 to perform rotation control of the outdoor unit 5 and then returns to the above-described step S2.
On the other hand, if the determination in step S8 is “NO” that does not satisfy the condition, the process directly returns to step S2.
Thus, during the operation of one outdoor unit 5, the control from step S <b> 2 to step S <b> 9 described above is repeated, and the operating time difference between the two outdoor unit 5, 5 is made substantially uniform.

  As described above, according to the GHP 1 of the present invention, when the cooling operation and the heating operation are performed at the low outside air temperature, the rotation control for switching the operation and the suspension of the outdoor unit 5 is performed. It is possible to prevent the liquid refrigerant from condensing and accumulating in the suction pipe of the outdoor unit 5) and the outdoor heat exchanger 23 when the operation is stopped. For this reason, it is possible to prevent the liquid refrigerant accumulated when starting the suspension unit from causing an excessive liquid back, and a large amount of liquid refrigerant is condensed and accumulated in the outdoor heat exchanger 23 during the heating operation. Therefore, it is possible to prevent a decrease in air conditioning capacity due to gas low operation. Such an effect is particularly remarkable in the GHP 1 including a multi-combination machine that is used in combination with the outdoor unit 5 having no accumulator.

In addition, when the operation time difference Δt between the two outdoor unit units 5 and 5 becomes larger than a predetermined value, rotation control is performed to switch the operation and suspension of the outdoor unit 5, so both outdoor unit units 5 can be made substantially uniform. For this reason, since the gas engine 53 is provided, it becomes possible to arrange the maintenance time of the outdoor unit 5 required every predetermined operation time.
As described above, according to the GHP 1 of the present invention, the accumulation of the liquid refrigerant generated on the outdoor unit unit 5 that is stopped at the low outdoor temperature is prevented, and the operation time for each outdoor unit 5 is equalized and predetermined. The maintenance time required after the operation time elapses can be aligned.

By the way, in embodiment mentioned above, it was set as the multi combination outdoor unit which uses two outdoor unit units 5 combining, However, It can be applied to the multi combination outdoor unit which combined three or more units | sets. Not too long.
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.

It is a figure which shows the refrigerant | coolant flow at the time of the whole structure and air-conditioning driving | operation of a gas heat pump type air conditioning apparatus (GHP) as an example of the air conditioning apparatus 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. 1, 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. 1, and the refrigerant | coolant flow at the time of air_conditionaing | cooling operation. It is a flowchart which shows the rotation control of the outdoor unit implemented when an operation time difference becomes larger than predetermined value.

Explanation of symbols

1 Gas heat pump type air conditioner (air conditioner)
9 Indoor heat exchanger (heat absorber, radiator)
11 Indoor electronic expansion valve (throttle part)
15 Temperature sensor 17 Compressor 21 Four-way valve (switching unit)
23 Outdoor heat exchanger (heat absorber, radiator)
24 Outdoor fan 25 Outdoor expansion valve (throttle part)
29 Supercooling coil (cooling heat exchanger)
31 Water heat exchanger (heat exchanger for heating)
37 Control unit 43 Suction temperature sensor 45 Suction pressure sensor 49 Supercooling expansion valve (cooling throttle)
51 Expansion valve for water heat exchanger (throttle for heating)
71 Machine room temperature sensor 73 Outside air temperature sensor

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,
During cooling operation in which at least one of the outdoor unit is operated,
There is an outdoor unit that is suspended for a predetermined time or more, and the state where the temperature difference between the suction pipe temperature sensor detected temperature and the suction pressure saturation temperature is smaller than a predetermined value continues for a predetermined time or more, Rotation control is performed to switch the operation and suspension of the outdoor unit when the detected temperature of the machine room temperature sensor of the suspension unit is lower than a comparison temperature obtained by adding a predetermined value to the suction pressure saturation temperature for a predetermined time or more. A gas heat pump type air conditioner. 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,
During heating operation in which at least one of the outdoor unit is operated,
There is an outdoor unit that has been in a suspended state for a predetermined time or more, and a state where the temperature difference between the outside air temperature sensor detected temperature of the suspended unit and the suction pressure saturation temperature is smaller than a predetermined value continues for a predetermined time or more, Rotation for switching the operation and suspension of the outdoor unit when the temperature difference between the temperature detected by the liquid heat sensor in the outdoor heat exchanger of the unit and the suction pressure saturation temperature is smaller than a predetermined value for a predetermined time or more. A gas heat pump type air conditioner characterized in that control is performed.   3. The rotation control is performed in which the operation time of the outdoor unit is compared, and when the operation time difference becomes larger than a predetermined value, rotation control for switching the operation and suspension of the outdoor unit is performed. Gas heat pump type air conditioner.

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