JPH05622B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention connects a plurality of indoor units to one outdoor unit so that cooling or heating operation can be selected individually, so that the outdoor unit can reduce the overall load. This invention relates to a heat recovery type air conditioner that can perform accurate capacity control corresponding to.

(Prior art) A plurality of indoor units are connected in parallel to one outdoor unit, and when at least one indoor unit is operating for cooling, at least one remaining indoor unit is operated for heating. Drivable and not,
Furthermore, during this operation, an air conditioner capable of so-called heat recovery, in which the heat radiated for cooling can be directly used as a heat source for heating, is known from Japanese Patent Laid-Open No. 12372/1983.

In this known example, as schematically shown in FIG. 7, the outdoor unit A includes a compressor 1, a heat source side coil 2, a discharge gas on-off valve 3D, an intake gas on-off valve 3S, a liquid side main pipe 5, a high-pressure gas side main pipe 6, low pressure gas side main pipe 7,
A heating expansion valve 34 is provided, while each indoor unit
A cooling expansion valve 8, a utilization side coil 9, a high-pressure gas side branch pipe 11 with on-off valves 13A to 13C interposed therein, and on-off valves 14A to 14C are interposed in I _A , I _B , _and I C, respectively. This circuit configuration includes low-pressure gas side branch pipes 12, respectively.

In the above air conditioner, the indoor units I _A and I _B that are to be cooled have on-off valves 14A and 14B.
On the other hand, in the indoor unit I _C that wants to perform heating, it is sufficient to open the on-off valve 13C, but in the outdoor unit A, it is necessary to open the on-off valve 13C. If the cooling load is large depending on the operating state, the heat source side coil 2 must act as a condenser, so the on-off valve 3
On the other hand, when the heating load is large, the heat source side coil must act as an evaporator, so it is necessary to open the on-off valve 3S.

(Problems to be Solved by the Invention) The air conditioner with this structure operates partly in cooling operation,
When performing heat recovery operation by operating the remainder of the unit into heating operation, there are states in which the heating load and cooling load are balanced, states in which the heating load is greater, and states in which the cooling load is greater. When the heating load is larger, such as in winter, the heat source side coil 2 naturally acts as an evaporator, but in that case, the evaporation temperature of the heat source side coil 2 needs to be lowered because the outside air temperature is low. As a result of this, frost grows rapidly on the user-side coil 9 of the indoor unit that is running the cooling operation, resulting in a great inconvenience of having to defrost it over and over again. There were disadvantages in that the frequency of starting and stopping increased, the fluctuations in the temperature of the room temperature were severe, and the coefficient of performance was also poor.

The present invention has been made in view of the disadvantage that conventional heat recovery type air conditioners frequently generate frost that hinders cooling operation. Frost formation can be eliminated by distinguishing between the heat source side coil for low-temperature evaporation and the user-side coil for high-temperature evaporation and allowing operation in two systems only when the side coil is performing heat absorption operation. The purpose is to improve the coefficient of performance and enable heat recovery operation accompanied by cooling operation that is smooth and at a stable temperature, and is fully adapted to the demands of the demand side.

(Means for Solving the Problems) Therefore, the present invention provides an outdoor unit A having a compression mechanism 1, a heat source side coil 2 that can be switched to act as a condenser or an evaporator, and a refrigerant flow rate control device 4;
It has a cooling pressure reducer 8 and a usage side coil 9,
In a heat recovery air conditioner comprising a plurality of indoor units I _A and I _B connected in parallel to the outdoor unit A so as to be individually switchable to cooling operation or heating operation, the compression mechanism 1 is It is composed of a plurality of compressors 1A and 1B divided into systems, while a part of each indoor unit I _A and I _B performs cooling operation, the remainder performs heating operation, and the heat source side coil 2 is used as an evaporator. During air conditioning operation, the suction side of one system in the compression mechanism 1 is connected to the gas side pipe of the outdoor unit A, and the suction side of the other system is separately connected to the indoor unit in cooling operation, During other air conditioning operations, the compression mechanism 1 is provided with a switching device 16 that commonly connects the suction sides of both systems to the suction line of the outdoor unit A or to the indoor unit in cooling operation. .

Further, the present invention provides that the compression mechanism 1 has a switching port on the suction side of one system, a switching port on one end of the heat source side coil 2, and a switching port on the high pressure side common to the discharge side of each compressor 1A, 1B of the compression mechanism 1. The ports are connected to the low pressure side ports of the first switching valve device 13, and the suction side of the other system is connected to the low pressure gas side main pipe 7 to which the indoor units I _A and I _B are branch-connected.
The switching device 16 is connected to an on-off valve 1 which is openable and closable in the middle of a pipe connecting the suction sides of both systems in the compression mechanism 1.
6 is also a preferred embodiment.

(Function) Therefore, in the present invention, when the cooling load is larger than the cooling load and the heat source side coil 2 serves as an evaporator, and when performing heat absorption operation, the compression mechanism 1 is connected to the heat source side coil 2 for low-temperature evaporation. Compressor 1A is connected to the user-side coil 9, which acts as an evaporator, and compressor 1B is operated for high-temperature evaporation. By operating the compressor 1A separately, the compressor 1B is connected to the user-side coil 9, which acts as an evaporator, and is operated for high-temperature evaporation. It is desirable that the system is operable, requires less power, and improves the overall coefficient of performance, and it is also possible to suppress frost formation on the user-side coil 9 indoors as much as possible.

(Example) Embodiments will be described in detail below based on the accompanying drawings.

In Fig. 1, A is an outdoor unit _{, I A} , I _B , and I _C are indoor units _;
is connected to the outdoor unit A via a liquid side main pipe 5, a high pressure gas side main pipe 6 and a low pressure gas side main pipe 7.

The outdoor unit A has a compression mechanism capable of controlling the capacity, for example, a capacity control device 19A, 1 such as a frequency converter.
9B (see FIG. 2), two compressors 1A and 1B each having an electric motor directly connected to the shaft, a heat source side coil 2, a refrigerant flow control device 4, for example, an electric refrigerant flow control valve 4, and a A refrigerant circuit is provided with a one-valve switching device 3, a switching device 16 such as an on-off valve 16, and a liquid receiver 29, and an outdoor fan 28 is attached thereto.

The refrigerant flow control valve 4 (hereinafter abbreviated as control valve 4) is installed in the liquid side main pipe 5, and has an electric device such as a pulse motor or an electromagnetic plunger as a driving element to correspond to the input electricity amount. The expansion valve is capable of adjusting the valve opening degree, and the valve opening degree can be easily adjusted by electrical control.

The first switching valve device 3 includes two on-off valves 3D and 3S as elements, has a high pressure side port, a low pressure side port, and a switching port that connects and communicates with both ports, Side open/close valve 3S
The coils are formed so that they can be alternately switched and communicated with the heat source side coil 2 by opening of the coils.

The compression mechanism 1 has a plurality of compressors 1A and 1B divided into two systems in parallel, for example, two compressors 1A and 1B.
The discharge sides are connected together to the high pressure side port of the on-off valve 3D and the high pressure gas side main pipe 6, while the suction side of one compressor 1A is connected to the suction side port of the on-off valve 3S, and the other compressor 1B is connected to the suction side port of the on-off valve 3S. The suction side of each is connected to the low pressure gas side main pipe 7, respectively.

The suction sides of the compressors 1A and 1B are connected to each other by piping, and a switching device 16, specifically an on-off valve 16, is interposed in the middle of the piping.

Next, each of the indoor units I _A to I _C has a circuit configuration in which a cooling pressure reducer 8 and a user-side coil 9 are connected in series, and a check valve 27 is connected in parallel to the pressure reducer 8. At the same time, the inflow sides of the cooling pressure reducer 8 are connected to the liquid side main pipe 5, and one end of the utilization side coil 9, which becomes the outlet during cooling operation, is connected to a high-pressure valve with on-off valves 13A to 13C interposed therein. It is connected to the high pressure gas side main pipe 6 by a gas side branch pipe 11, and is connected to the low pressure gas side main pipe 7 by a low pressure gas side branch pipe 12 in which on-off valves 14A to 14C are respectively interposed. The second switching valve devices 10A to 10C are formed by a combination of the two types of on-off valves 13A to 13C and the on-off valves 14A to 14C.

Note that 15 is a fan for the coil 9 on the user side.

In the air conditioner with the circuit configuration described above, when you want to perform cooling operation with the indoor units I _A to I _C , open the on-off valves 14A to 14C, and open the on-off valves 13A to 13.
C is opened and the on-off valves 14A to 14C are closed.

On the other hand, in outdoor unit A, depending on whether the total load on the indoor side is a cooling load or a heating load, the heat source side coil 2 needs to act as a condenser or an evaporator. It is sufficient to open the on-off valve 3D and close the on-off valve 3S. In the latter case, it is sufficient to open the on-off valve 3S and close the on-off valve 3D.

The capacity of the compressor 1 is controlled by the capacity control devices 19A and 19B, while the amount of refrigerant flowing into the heat source coil 2 is controlled by the valve opening control device 20 that operates the control valve 4. These devices 19A, 19B, 20
The control device 17 includes a switching controller 21 that switches the valves of the first switching valve device 3, and an opening/closing controller 26 that opens and closes the opening/closing valve 16.

As mentioned above, indoor units I _A to I _C can be switched to cooling or heating at will, and when cooling and heating are operated at the same time, the condensation is adjusted to match the difference between the cooling load and the heating load. By having the heat source side coil 2 on the outdoor side carry the capacity or evaporation capacity, heat recovery operation that efficiently utilizes exhaust heat becomes possible.

In this case, the operation mode of the heat source side coil 2 is determined by the relationship between the cooling load and the heating load, the capacity of the compression mechanism 1, the opening degree of the control valve 4, and the on-off valves 3D, 3S, 16.
Fig. 3 shows the relationship between the opening and closing states of the evaporator and the opening/closing state. ing.

As is clear from FIG. 3, if you want to make the heat source side coil 2 act as a condenser and control its capacity, you can open the on-off valve 3D, close the on-off valve 3S, and adjust the opening degree of the control valve 4. , conversely, if you want to function as an evaporator and control the capacity, use the on-off valve 3.
The opening degree of the control valve 4 may be adjusted by opening S and closing the on-off valve 3D.

In addition, if you want the heat source side coil 2 to act as a condenser, open the on-off valve 16 and compressor 1A, 1
If you wish to operate B in parallel and operate them conversely as an evaporator, close the on-off valve 16 so that the compressor 1A sucks refrigerant from the heat source coil 2, and the compressor 1B sucks refrigerant from the user coil 9. The purpose is to have each person share in the tasks.

Further, by jointly controlling the capacity of the compressors 1A and 1B, it is possible to perform a refrigeration operation with no excess or deficiency commensurate with the air conditioning load.

Although not shown in FIG. 3, when all of the indoor units I _A to I _B are operating for cooling or heating, the on-off valve 16 is kept open.

Control command means 1 for giving control commands to the control device 17 that meet the purpose of the refrigeration operation described above.
8 will be explained below based on the drawings.

The control command means 18 is a high pressure and force detection circuit 2.
2. Low pressure and force detection circuit 23, superheat degree detection circuit 2
5. Secondary ability determination circuit 30, switching valve control circuit 3
1. It is composed of eight circuits: a first switching valve control circuit 32 and an on-off valve control circuit 33, and the functions of each circuit are explained below.

◎High-pressure force detection circuit 22, pressure sensor that detects the pressure of the high-pressure gas side main pipe 6
S ₁ as a detection end, and if the high pressure force detected by the sensor S ₁ is within the range of set conditions, that is, within the pressure band, a high pressure appropriate signal is issued;
If the pressure is lower than the pressure band, a high pressure shortage signal is generated, and if it is higher than the pressure band, a high pressure excess signal is generated.

Note that a temperature sensor that can detect the discharge side saturation temperature and convert it into pressure may be used instead of the pressure sensor _S1 .

◎Low pressure force detection circuit 23, pressure sensor that detects the pressure of the low pressure gas side main pipe 7
If the low pressure force detected by the sensor _S2 is within the range of the set conditions, that is, within the compressive force band _, it is a low pressure appropriate signal, if it is low, it is a low pressure insufficient signal, and if it is high, it is a low pressure excessive signal. The pressure sensor S ₂ may be replaced with a temperature sensor, similar to the pressure sensor S 1, although the pressure sensor S ₂ generates a signal, respectively.

◎Superheat degree detection circuit 24 has sensors S ₃ and S ₄ for detecting the refrigerant temperature at the inlet and outlet of the heat source side coil 2 when the heat source side coil 2 acts as an evaporator, and these two sensors The temperature difference between S ₃ and S ₄ is the degree of superheat.

Note that the sensor S ₃ may detect pressure and electrically convert it into a temperature signal.

◎Primary capacity determination circuit 25, high pressure and force detection circuit 22, and low pressure and force detection circuit 23
This is a logic circuit that receives both output signals, distinguishes nine types of signals obtained by the combination, and converts them into five types of output signals. The capacity control device 19B sends a capacity increase signal to increase the capacity of the compressor whose suction side is connected to the low pressure gas side main pipe 7.
AND of the high voltage over-voltage signal and the low-voltage under-voltage signal
A capacity reduction signal is issued to the device 19B to reduce the capacity of the compressor 1B.

In addition, a cool < warm mode signal is generated by ORing the high voltage shortage signal and low pressure appropriate signal, the high voltage shortage signal and low pressure shortage signal, and the high voltage appropriate signal and low pressure shortage signal, and generates a cool < warm mode signal. A cool>warm mode signal is generated by ORing the excessive signal, the low pressure excessive signal, and the high pressure excessive signal and the low pressure appropriate signal.

Furthermore, a hold signal is generated by ANDing the high voltage appropriate signal and the low voltage appropriate signal.

◎Second capacity judgment circuit 30, high pressure and force detection circuit 22, low pressure and force detection circuit 23
In response to each output signal from the primary ability determination circuit 25, the following signals are output.

(b) Output group under the condition that the primary capacity determination circuit 25 issues a cold < warm mode signal, and when the high pressure/strength detection circuit 22 issues a high pressure shortage signal, the compressor 1A, that is, the on-off valve 3S
A capacity increase signal is sent to the capacity control device 19A to increase the capacity of the compressor whose suction side is connected to the low pressure side port of the compressor 1A.
The device 1 sends a capacitance reduction signal to reduce the capacitance of the device 1.
Emit at 9A.

Further, when the low pressure and force detection circuit 23 is emitting a low pressure excessive signal, a capacity increase signal for increasing the capacity of the compressor 1B is sent to the capacity control device 19B, and conversely, when the low pressure insufficient signal is emitted, the capacity increase signal for increasing the capacity of the compressor 1B is sent to the capacity control device 19B. A capacity reduction signal is issued to the device 19B to decrease the capacity.

Further, a hold signal is generated by ANDing the high pressure appropriate signal and the low pressure appropriate signal of both pressure detection circuits 22 and 23.

(b) Output group under the condition that the primary capacity determination circuit 25 issues a cold>warm mode signal, the high pressure insufficient signal of the high pressure and force detection circuit 22 and the low pressure appropriate signal or low pressure excessive signal of the low pressure and force detection circuit 23 A capacity increase signal for increasing each capacity of the compressors 1A and 1B is sent to the capacity control devices 19A and 19B by ANDing the appropriate high pressure signal and the low pressure excessive signal, and also by ANDing the high pressure appropriate signal and the low pressure excessive signal. AND with the low pressure shortage signal,
A capacity reduction signal for reducing the capacity of each of the compressors 1A and 1B is issued to both the devices 19A and 19B by ANDing the high voltage appropriate signal and the low pressure insufficient signal.

On the other hand, the control valve control circuit 3 generates a valve opening increase signal that increases the opening of the control valve 4 by ANDing the low pressure excessive signal and the high pressure proper signal or the high pressure excessive signal, and by ANDing the low pressure proper signal and the high pressure excessive signal.
1, and also by AND of the low pressure shortage signal and the high pressure shortage signal or the high pressure appropriate signal, and the AND of the low pressure appropriate signal and the high pressure shortage signal.
The circuit 31 transmits a valve opening signal that decreases the opening of the circuit 31.
emanates from.

Also, the difference between the high voltage appropriate signal and the low voltage appropriate signal
A hold signal is generated by AND.

◎When the control valve control circuit 31 and the primary capacity determination circuit 25 issue a cold < warm mode signal, the superheat degree detection circuit 24
The valve opening control signal is such that a signal smaller than a predetermined superheat degree reduces the valve opening of the control valve 4, and a larger signal conversely increases the valve opening so that the signal becomes a low pressure appropriate signal. The valve opening control device 2
This is a stepless control over the control valve 4, and corresponds to control to maintain the heat source side coil 2, which acts as an evaporator, at a constant degree of superheat.

On the other hand, as described above, when the primary capacity determination circuit 25 is issuing a cold>warm mode signal, it receives a valve opening increase signal or a valve opening decrease signal and issues this to the valve opening control device 20. This is step control of the control valve 4 with a small unit opening, and corresponds to capacity control that attempts to adjust the heat dissipation capacity of the heat source side coil 2, which acts as a condenser, to the difference between the cooling load and the heating load. .

◎The first switching control circuit 32 and the first capacity determination circuit 25 issue a cold < warm mode signal to open the on-off valve 3S, and send a signal to the switching controller 21 to close the on-off valve 3D.
On the other hand, by issuing a cold>warm mode signal, a signal is issued to the switching controller 21 to open the on-off valve 3D and close the on-off valve 3S.

◎The on-off valve control circuit 33 and the primary capacity determination circuit 25 issue a signal to close the on-off valve 16 by issuing a cold<warm mode signal to the on-off valve controller 26; Open/close valve 16 by issuing a mode signal.
A signal is issued to the on-off valve controller 26 to open it.

Although the contents of the control command means 18 have been described above, the outline of the operation mode of the air conditioner shown in FIG. 1 will now be explained with further reference to FIGS. 2 to 6.

Open the on-off valve 3S, open the on-off valve 3D and the on-off valve 16
It is assumed that the heating cycle is closed and the heating load and the cooling load are balanced, and this is set as the initial condition and operation is started.

Note that under this initial condition, the compressor 1A is stopped, the compressor 1B is driven at the medium capacity of the initial operation, and the control valve 4 is kept fully closed (waiting for an opening command).

After the start of operation, this state is maintained for a predetermined period of time, such as at one-minute intervals, and then the primary ability determination circuit 25 performs the ability determination based on the check signal issued here.

That is, the capacity of the compressor 1B is determined by determining nine types of signals obtained by combinations of pressure detection ○D of the high pressure and force detection circuit 22 and pressure detection ○D of the low pressure and force detection circuit 23. A capacitance increase signal E ₁ , a capacitance decrease signal E ₂ , a hold signal E ₃ ,
Cool < warm mode signal E ₄ for requesting an increase in the capacity of the compression mechanism 1 because the heating load is larger, and request for capacity control of the compression mechanism 1 and capacity control of the heat source side coil 2 because the cooling load is larger. A cold>warm mode signal _E5 is selectively emitted for each operation.

When the hold signal _E3 is being issued, the current operation is continued and the capacity judgment is made again after 1 minute has elapsed.

On the other hand, when the capacity increase signal _E1 is being issued, the capacity control device 19B controls the compressor 1B to 1.
The capacity is increased by the amount of steps, and the ability is judged again after 1 minute has passed.

Conversely, when the capacitance reduction signal E ₂ is being issued,
The capacity of the compressor 1B is reduced by one step by the capacity control device 19B, and the capacity is determined again after one minute has elapsed.

In addition, when the cool<warm mode signal _E4 is being issued, the control valve control circuit 31 is switched to the constant superheat degree control side, and the secondary capacity judgment circuit 30 performs the capacity judgment. Cool > Warm mode signal
When E ₅ is issued, control valve control circuit 3
1 to the opening step control side, a switching command to the first switching valve control circuit 32, that is, a command to open the on-off valve 3D and close the on-off valve 3S, and a command to the on-off valve control circuit 33 to open the on-off valve 16.
○nu to cause an open command and a capability determination by the secondary capability determination circuit 30 to be performed.

Therefore, in the case of the former operation based on the cold < warm mode signal E ₄ , the combination is determined by the pressure detection ○D of the high pressure and force detection circuit 22 and the pressure detection ○E of the low pressure and force detection circuit 23. Nine types of signals obtained by
That is, a signal e 1 increases the capacity of the compressor 1A and decreases the capacity of the compressor 1B, a signal e ₂ increases the capacity of only the compressor 1A, a signal e ₃ increases the capacity of both compressors 1A and 1B, and a signal e ₃ increases the capacity of the compressor 1B. A signal e ₄ that causes the capacity of only the compressors 1A and 1B to be decreased, a signal e ₅ that causes the capacity of both compressors 1A and 1B to be held at the current capacity, a signal e ₆ that causes the capacity of only the compressor 1B to increase, a signal e that causes the capacity of both compressors 1A and 1B to decrease. ₇ , Signal e to reduce the capacity of compressor 1A only ₈ , Decrease the capacity of compressor 1A, and reduce the capacity of compressor 1A
Select and emit a signal _e9 that increases the capacitance of B,
The capacity of the compressors 1A and 1B is controlled in accordance with each of these signals.

Then, check whether the compressor 1A stops when the capacity of the compressor 1A becomes zero, that is, the cooling load and the heating load are balanced, and the pressure is detected again every minute until the compressor 1A stops. When the control valve 4 is stopped, the control valve 4 is fully closed, and the ability determination by the primary ability determination circuit 25 is repeated.

On the other hand, in the case of the latter operation based on the cold>warm mode signal _E5 , the combination Nine types of signals obtained by combining
That is, a signal e' ₁ that gradually decreases the opening of the control valve 4 by a unit opening, and a signal that similarly decreases the opening of the control valve 4 in stages and increases the capacity of both compressors 1A and 1B. e′ ₂ , signal e′ ₃ that increases the capacity of both compressors 1A, 1B, signal e′ that reduces the capacity of both compressors 1A, 1B, and decreases the valve opening degree of control valve 4 in stages. ₄ , a signal e' to maintain (hold) the opening degree of the control valve 4 and the capacity of both compressors 1A, 1B at the current state, ₅ , increase the capacity of both compressors 1A, 1B, and increase the valve opening degree of the control valve 4; A signal e' ₆ to increase the capacity in stages; a signal e' ₇ to decrease the capacity of both compressors 1A, 1B; A signal e' ₈ to increase the valve opening of the control valve 4 and a signal e' ₉ to increase the valve opening of the control valve 4 in stages are selected and emitted, and the capacity control of the compressors 1A and 1B and the control valve corresponding to these signals are performed. 4. The valve opening control is performed.

Then, check whether the opening degree of the control valve 4 is fully closed, and perform pressure detection again every minute until the cooling load and heating load are balanced. When this is reached, the compressor 1A is stopped, ○f is reached, and the original capacity judgment by the primary capacity judgment circuit 25 is repeated.

In addition, in the flow diagram, "Pc" indicates high pressure and force, "Pe"
indicates a low pressure, and HIGH, HIGH, and HIGH indicate a high-pressure insufficient signal, a high-pressure appropriate signal, and a high-pressure excessive signal, respectively.
Moreover, low-incorrect, low-proper, and low-over indicate a low-pressure insufficient signal, a low-pressure appropriate signal, and a low-pressure excessive signal, respectively.

As is clear from the above explanation, depending on the difference between the cooling load and the heating load, the capacity of the compressor 1 is controlled, the opening of the control valve 4 is controlled, the switching of the first valve switching device 3 is controlled, and the on-off valve 16 is controlled. Opening/closing control is performed automatically, enabling efficient heat recovery operation.

In particular, when at least a part of the utilization side coil 9 and the heat source side coil 2 are used as an evaporator at the same time, the on-off valve 16 is closed and the compressor 1A is operated at a suction pressure of, for example, a pressure equivalent to -5°C. By using the suction pressure at a pressure equivalent to 5°C, for example, and using it as a separate system, the compressor 1B on the indoor side can be used under advantageous conditions, preventing frost formation on the user side coil 9, and further reducing the capacity of the compressor 1B. It is expected that the coefficient of performance will improve.

(Effects of the Invention) The present invention divides the compression mechanism 1 in a heat recovery air conditioner into two systems, so that part of the indoor units I _A and I _B performs cooling operation, and the remaining part performs heating operation. During air conditioning operation in which the heat source side coil 2 acts as an evaporator, one system of the compression mechanism 1 is used for sucking refrigerant from the heat source side coil 2, and the other system is used for sucking refrigerant from the user side coil 9. Since they are used separately, the compressor associated with the utilization side coil 9 can be operated under advantageous conditions, and frost formation on the coil can be reliably prevented, reducing the compressor capacity and improving the coefficient of performance. You can expect that.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration circuit diagram according to an embodiment of the present invention,
FIG. 2 is an electric circuit block diagram, FIG. 3 is an explanatory diagram of the operating state of the device shown in FIG. 1, and FIGS.
FIG. 1 is a flow diagram showing the operation control mode of the apparatus shown in FIG. 1, and FIG. 7 is a refrigeration circuit diagram of a conventional air conditioner. 1... Compression mechanism, 1A, 1B... Compressor, 2... Heat source side coil, 3... First switching valve device, 4... Refrigerant flow rate control device, 7... Low pressure gas side main pipe, 8... Cooling pressure reducer, 9... Utilization Side coil, 16... switching device, A... outdoor unit, I _A , I _B ... indoor unit.

Claims (1)

[Scope of Claims] 1. An outdoor unit A having a compression mechanism 1, a heat source side coil 2 that can function as a condenser or an evaporator, and a refrigerant flow rate control device 4, and a cooling pressure reducer 8.
and a utilization side coil 9, and the outdoor unit A can be individually switched to cooling operation or heating operation.
Multiple indoor units I _A , I _B connected in parallel to
In a heat recovery air conditioner comprising: a plurality of compressors 1 in which the compression mechanism 1 is divided into two systems;
A and 1B, while each indoor unit
When a part of I _A and I _B performs cooling operation, and the remaining part performs heating operation, and the heat source side coil 2 acts as an evaporator during air conditioning operation, the suction side of one system in the compression mechanism 1 is placed outdoors. The suction side of the other system is separately connected to the gas side pipe of unit A and the indoor unit in cooling operation, and during other air conditioning operations, the suction side of both systems is connected to the suction line of outdoor unit A or cooling. A heat recovery air conditioner characterized in that the compression mechanism 1 is provided with a switching device 16 that is commonly connected to indoor units in operation. 2 Multiple compressors 1A, 1 divided into 2 systems
A compression mechanism 1 consisting of a plurality of compressors 1A and 1B has a switching port at one end of the heat source side coil 2.
The suction side of one system is connected to the low pressure side port of the first switching valve device 3, which has a high pressure side port commonly connected to each discharge side of the system, and the suction side of the other system is connected to the low pressure side port of the first switching valve device 3. , each indoor unit I _A , I _B is connected to the branch-connected low pressure gas side main pipe 7,
Furthermore, the heat recovery type air according to claim 1, wherein the switching device 16 is formed of an on-off valve 16 that is openable and closable in the middle of the piping that connects the suction sides of both systems in the compression mechanism 1. harmonizer.