JPH0610569B2 - Operation controller for heat recovery type air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an operation control device of a heat recovery type air conditioner in which a plurality of indoor units are individually connected to an outdoor unit so as to be capable of heating / cooling operation, and particularly to a high pressure The present invention relates to an improvement of the outdoor capacity control according to the low pressure value and the low pressure value.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 61-110859, a plurality of indoor units are connected in parallel to an outdoor unit, and a gas of a heat exchanger on the use side of each indoor unit is connected. A high-pressure sensor in the discharge line as an operation control device of a so-called heat recovery type air conditioner that is configured to individually switch the connection with the discharge line and the suction line to enable individual heating and cooling operation of each indoor unit. , The low pressure sensor is arranged in the suction line, and the high voltage signal and the low voltage signal during operation are excessive with respect to the target value,
Switching between the evaporation and condensation cycles of the heat source side heat exchanger on the outdoor unit side so that the high pressure and the low pressure converge to a predetermined range in accordance with a total of nine types of signals consisting of three types of combinations of proper and undersized. By controlling the opening of the flow rate adjusting mechanism that adjusts the refrigerant flow rate of the heat source side heat exchanger and the operating capacity of the compressor, there is one that tries to ensure proper operation according to the air conditioning load in each indoor unit. Are known.

(Problems to be solved by the invention) By the operation control device of the heat recovery type air conditioner, while performing the cooling operation and the heating operation individually according to the air conditioning load on the indoor unit side, the outdoor unit side is comprehensively operated. It can be controlled to maintain a good balance of air conditioning capacity.

By the way, in that case, specifically, when the high pressure is excessive, proper, or too small, the excess heating capacity signal, the proper heating capacity signal, and the insufficient heating capacity signal are respectively set, and the low pressure is too small, proper, or
Assuming that the excess cooling capacity signal, the proper cooling capacity signal, and the insufficient cooling capacity signal when the temperature is excessive, as shown in the table below, the heat source is supplied to the two signals according to the magnitude relationship between the cooling required capacity and the heating required capacity. The cycle switching of the side heat exchanger and the opening degree of the flow rate control mechanism are controlled to the condensing action side or the evaporating action side, and one of them is an appropriate heating (cooling) capability signal and the other is an insufficient cooling (heating) capability signal. When either or both are insufficient warm (cooling) capacity signals, control is performed to increase the operating capacity of the compressor. One of them is an appropriate warm (cooling) capacity signal and the other is an excessive cooling (warming) capacity signal. Occasionally, the operating capacity of the compressor is controlled to decrease (however, in the table below, "capacity increase" and "capacity decrease" are respectively adjusted to increase and decrease the operating capacity of the compressor (1). Show "condensation direction", "evaporation direction" To the condensing cycle of the heat source side heat exchanger and adjusting the opening of the flow rate control mechanism to the increasing side, and to the evaporation cycle of the heat source side heat exchanger and to the increasing side of the flow rate controlling mechanism. Adjustment).

However, when the excess heating capacity signal is the insufficient cooling capacity signal and when the excess cooling capacity signal is the insufficient heating capacity signal, the operating capacity of the compressor is not controlled only by controlling the opening degree of the flow rate control mechanism. There are the following problems.

That is, for example, when all the indoor units are performing the cooling operation, there is an excess heating capacity signal, and even if the cooling capacity is insufficient, since only the control for causing the heat source side heat exchanger to act in the condensation direction is performed, When the opening degree of the flow rate control mechanism reaches the fully open value or the supercooling degree reaches the lower limit value, the capacity of the outdoor unit side cannot be further increased. On the other hand, if an attempt is made to eliminate such inconvenience by setting the high pressure target value high, the coefficient of performance will inevitably deteriorate.

Similarly, when all the indoor units are performing heating operation, even if there is an excess cooling capacity signal and the heating capacity is insufficient, the control is such that only the heat source side heat exchanger acts in the evaporation direction. Similarly, it becomes impossible for the outdoor unit to secure a predetermined capacity.

The present invention has been made in view of the above problems, and an object thereof is to control the capacity of a compressor when all the indoor units have insufficient cooling capacity or heating capacity during cooling operation or heating operation. As a result, a predetermined heat recovery operation can be performed without causing a capacity shortage on the outdoor unit side.

(Means for Solving the Problem) In order to achieve the above object, the first solution means of the present invention is, as shown in FIG. 1, a variable capacity compressor (1), a heat source side heat exchanger (3). Also, for the outdoor unit (X) having a flow rate control mechanism (4) having a refrigerant flow rate adjusting function and a pressure reducing function for the heat source side heat exchanger (3), the use side heat exchanger (7) and the utilization A refrigerant circuit (12) in which a plurality of indoor units (A) to (C) having a pressure reducing mechanism (6) for a side heat exchanger (7) are connected in parallel by a refrigerant pipe (11).
And the heat exchangers (3), (7) to
(7) so that the refrigerant circulates in the evaporation cycle functioning as an evaporator or the condensation cycle functioning as a condenser,
Refrigerant circuit (12) of each heat exchanger (3), (7) to (7)
The gas line (11b) of the discharge line (11b)
It is premised on the heat recovery type air conditioner provided with a connection switching mechanism (51) for individually switching between the c) side and the suction line (11d) side.

Then, as an operation control device of the heat recovery type air conditioner, a high pressure detecting means (Pc) which is arranged in the discharge line of the refrigerant circuit (12) and detects a high pressure, and an intake line (1).
1d), which is a low pressure detection means (P
e), gas-liquid differential temperature detection means (50) for detecting the degree of supercooling of the refrigerant in the heat source side heat exchanger (3), and outputs of the high pressure detection means (Pc) and low pressure detection means (Pe). , A refrigerant action control means (52) for controlling the heat source side heat exchanger (3) in the condensation action direction when both the high pressure and the low pressure are higher than the appropriate range, the refrigerant action control means (52) and the above. When the supercooling degree of the refrigerant reaches the lower limit value during the control by the refrigerant action control means (52) by receiving the output of the gas-liquid differential temperature detection means (50) or the flow rate control mechanism (4)
When the opening of the compressor is fully opened, a capacity control means (53) for changing the operating capacity of the compressor (1) to the increasing side is provided.

Further, the second solving means is premised on the heat recovery type air conditioner similar to the first solving means, and is further provided with the same high pressure detecting means (Pc) and low pressure detecting means (Pe).

Further, receiving the outputs of the gas-liquid differential temperature detecting means (50) for detecting the degree of superheat of the refrigerant in the heat source side heat exchanger (3) and the high pressure detecting means (Pc) and the low pressure detecting means (Pe),
When both high pressure and low pressure are lower than the proper range,
Refrigerant action control means (52) for controlling the heat source side heat exchanger (3) in the evaporation action direction, and the refrigerant action control means (5)
2) and the output of the gas-liquid differential temperature detection means (50), when the degree of superheat of the refrigerant reaches the lower limit value or the opening degree of the flow rate control mechanism (4) during the control by the refrigerant action control means (52). When fully opened, a capacity control means (53) for changing the operating capacity of the compressor (1) to the increasing side is provided.

(Operation) With the above configuration, in the invention of claim (1), the high pressure value and the low pressure detection means (Pc) detected by the high pressure detection means (Pc).
In the case where the low pressure values detected in e) are both higher than the predetermined appropriate range and the excess heating capacity signal and the insufficient cooling capacity signal are obtained, for example, at the time of 100% cooling operation of the device, the heat source side heat exchanger ( When the condensing capacity of 3) is insufficient, the refrigerant action control means (52) increases the condensing capacity of the heat source side heat exchanger (3), that is, by switching the connection switching mechanism (51). The heat source side heat exchanger (3) is controlled in the condensation cycle and the opening degree of the flow rate control mechanism (4) is increased.

When the proper condition is not reached even by adjusting the opening degree and the degree of supercooling reaches the lower limit value during that time so that the opening degree cannot be further increased or when the opening degree itself becomes the fully open value, the capacity control means (53) Thus, the operating capacity of the compressor (1) is controlled to increase, so that the refrigerant flow rate increases and the condensing capacity of the heat source side heat exchanger (3) increases. Therefore, the balance between the cooling capacity and the heating capacity during the operation of the device is effectively prevented from being upset, and a comfortable air conditioning feeling is maintained.

Further, in the invention of claim (2), when both the high pressure value and the low pressure value are lower than the proper ranges and the insufficient heating capacity signal and the excessive cooling capacity signal are obtained, for example, the indoor units (A) to ( When the evaporation capacity of the heat source side heat exchanger (3) is insufficient during the total heating operation of C), the refrigerant operation control means (52) increases the evaporation capacity of the heat source side heat exchanger (3). Direction, that is, the connection switching mechanism (51)
The heat source side heat exchanger (3) is controlled to switch to the evaporation cycle and the opening degree of the flow rate control mechanism (4) is increased by switching.

When the proper condition is not reached even by adjusting the opening and the degree of superheat reaches the lower limit during that time, and the opening cannot be further increased, or when the opening itself reaches the fully open value, the capacity control means (53) As a result, the operating capacity of the compression decision (1) is controlled to increase, so that the refrigerant flow rate increases and the evaporation capacity of the heat source side heat exchanger (3) increases. Therefore, it is possible to obtain the same effect as that of the invention of claim (1).

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows the overall configuration of the air conditioner according to the embodiment of the present invention, in which three indoor units (A) to (C) are arranged in parallel with respect to one outdoor unit (X). . The outdoor unit (X) includes a variable capacity compressor (1) driven by an inverter (not shown) with a variable operating frequency, and a heat source functioning as a condenser or an evaporator depending on the flow direction of the refrigerant. An outdoor heat exchanger (3) as a side heat exchanger and a solid line in the figure during a condensation cycle in which the outdoor heat exchanger (3) functions as a condenser, and a dashed line in the figure during an evaporation cycle that functions as an evaporator. That is, that is, the first four-way switching valve (2) that switches the flow of the refrigerant to the outdoor heat exchanger (3) between the evaporation cycle and the condensation cycle, and the refrigerant flow rate to the outdoor heat exchanger (3) is adjusted. With
A first electric expansion valve (4) as a flow rate control mechanism that also reduces the pressure of the refrigerant when the outdoor heat exchanger (3) functions as an evaporator; a receiver (5) for storing liquid refrigerant;
An accumulator (8) for separating the liquid refrigerant in the suction gas to the compressor (1) is arranged.

In addition, the indoor units (A) to (C) have the same configuration, and the indoor heat exchanger (7) as a use-side heat exchanger functions as an evaporator or a condenser according to the flow of the refrigerant. And a second electric expansion valve (6) as a pressure reducing mechanism for reducing the pressure of the refrigerant to the indoor heat exchanger (7).

The respective devices (1) to (8) in the respective units (X) and (A) to (C) are sequentially connected to each other by a refrigerant pipe (11) so that the refrigerant can flow. X), (A)-(C) heat exchangers (3), (7)-
A refrigerant circuit (12) for exchanging heat between the heat given in (7) through the refrigerant is configured.

Here, the gas line (11b) of the refrigerant circuit (12)
For each indoor unit (A) to (C), the solid line in the figure indicates the evaporation cycle in which the heat exchangers (7) to (7) function as evaporators, and the diagram indicates the condensation cycle in which the heat exchangers (7) to (7) function as condensers. Switching is performed as indicated by the middle broken line, and the connection between the heat exchangers (7) to (7) and the gas line (11b) is connected to the discharge line (11c) side and the suction line (11d) side of the compressor (1). Second to fourth four-way switching valves (14) to (16) for individually switching are arranged. The first four-way switching valve (2) and the second to fourth four-way switching valves (1
4) to (16), each heat exchanger (3), (7) to
(7) so that the refrigerant circulates in the evaporation cycle functioning as an evaporator or the condensation cycle functioning as a condenser,
Gas line (11) of each heat exchanger (3), (7)-(7)
Connection switching mechanism (51) for individually switching the connection with b) to the discharge line (11c) side and the suction line (11d) side
Is configured.

On the other hand, sensors are installed in the outdoor unit (X), (Pc) is arranged in the discharge line (11c), and a high-pressure sensor as a high-pressure detection means for detecting the high-pressure value Tc,
(Pe) is placed in the suction line (11d) and has a low pressure value T
a low pressure sensor as a low pressure detection means for detecting e, (Th
1) is attached to the liquid pipe side of the outdoor heat exchanger (3), a liquid pipe sensor for detecting the liquid pipe temperature T1, (Th2) is attached to the gas pipe side of the outdoor heat exchanger (3) A gas pipe sensor (Th2) for detecting the gas pipe temperature T2,
By the high pressure sensor (Pc), the low pressure sensor (Pe), the liquid pipe sensor (Th1) and the gas pipe sensor (Th2), the superheat degree Sh in the vapor-liquid differential temperature of the refrigerant (that is, during the evaporation cycle of the outdoor heat exchanger (3)) , Subcooling degree Sc during the condensation cycle)
The gas-liquid differential temperature detection means (50) is configured to detect In addition, each of the sensors (Pc), (Pe),
(Th1) and (Th2) are connected to a controller (10) for controlling the operation of the entire apparatus so that signals can be input, and the controller (10) allows each sensor (P) to operate.
c), (Pe), (Th1), (Th2) signals,
The device is controlled in each operation mode according to the required capacity in each room.

In FIG. 2, (17) to (20) are heat exchangers (3) of the four-way switching valves (2), (14) to (16),
Capillarys (21a) to (21c) provided between one connection port facing the connection ports to (7) to (7) and the suction line (11d) are liquid lines (11).
a), suction line (11d) and discharge line (11
It is a manual on-off valve provided at the outlet of the outdoor unit (X) in c).

During total cooling operation of the indoor units (A) to (C), the four-way switching valves (2), (14) to (16) are switched as shown by solid lines in the figure, and the first electric expansion valve (4) is opened. Each indoor unit is operated after the discharge refrigerant is condensed in the outdoor heat exchanger (3) while the operation is performed moderately while appropriately adjusting the openings of the second electric expansion valves (6) to (6). The indoor heat exchangers (7) to (7) of (A) to (C) circulate so as to evaporate.

When the indoor units (A) to (C) simultaneously perform the heating operation, the four-way switching valves (2), (14) to (1).
All of 6) are switched to the broken line side in the figure, and the operation is performed by the refrigerant flow opposite to the above. Although not described, even if only one of the indoor units (A) to (C) is operating and the other is stopped, the operating state is similar to the above.

Further, in this device, the connection state of the connection switching mechanism (51) is switched according to the required capacity in each room, and operation in a so-called combined operation mode is performed in which each indoor unit (A) to (C) individually performs cooling and heating operation. Is done. For example, the indoor units (A) and (B) perform the cooling operation, and the indoor unit (C) performs the heating operation, so that the operation according to the demand in each room can be performed. That is, each four-way switching valve (2),
(14) and (15) are switched as shown by the solid line in the figure, and the fourth four-way switching valve (16) is switched as shown by the broken line in the figure, and the first electric expansion valve (4) and the second electric motor of the indoor unit (C) are switched. With the expansion valve (6) slightly open, and the indoor unit (A),
(B) The second electric expansion valves (6), (6) are operated while appropriately adjusting the openings, and the refrigerant discharged is the outdoor heat exchanger (3) and the indoor heat exchanger of the outdoor unit (C). (7)
After being condensed in, the indoor heat exchangers (7) and (7) of the indoor units (A) and (B) circulate so as to evaporate, so that the simultaneous heating and cooling operation corresponding to the difference in the conditions in each room can be performed. Then, a recovery operation is performed in which heat is mutually recovered on the indoor side.

Then, during operation of the indoor units (A) to (C), in the outdoor unit (X), the first electric expansion valve (4) is opened in response to the signals of the high pressure sensor (Pc) and the low pressure sensor (Pe). The operating capacity is controlled by the AR and the compressor (1) as shown in the table below.

However, in the above table, when the value of high pressure Tc detected by the high pressure sensor (Pc) is too small, within the range, or too large for the insufficient heating capacity signal, the appropriate heating capacity signal, and the excessive heating capacity signal, respectively. Indicates the insufficient cooling capacity signal,
The appropriate cooling capacity signal and the excessive cooling capacity signal indicate when the value of the low pressure Te detected by the low pressure sensor (Pe) is excessive, appropriate, or insufficient, respectively. Further, "capacity increase" and "capacity decrease" indicate the increase and decrease of the operating capacity of the compressor (1), respectively, and "condensation action direction" and "evaporation action direction" are indicated.
Are the switching of the outdoor heat exchanger (3) to the condensation cycle, the adjustment of the opening AR of the first electric expansion valve (4) to the increasing side, and the switching of the outdoor heat exchanger (3) to the evaporation cycle. Switching and adjustment of the opening degree AR of the first electric expansion valve (4) to the increasing side.

As shown in the above table, when one of the signals of the high pressure sensor (Pc) and the low pressure sensor (Pe) is an appropriate warm (cooling) capacity signal and the other is an insufficient cooling (warm) cooling capacity signal, or both. Is an insufficient warm (cool) air capacity signal, control is performed to increase the operating capacity of the compressor (1), and one is appropriately warm (cool).
When the other is the excess cooling (warming) air conditioning signal in the air conditioning capacity signal, the operating capacity of the compressor (1) is controlled to be reduced.

As for the opening AR of the first electric expansion valve (4), when one is the excess heating capacity signal and the other is the proper cooling capacity signal,
Alternatively, when one is an appropriate heating capacity signal and the other is an insufficient cooling capacity signal, the outdoor heat exchanger (3) is switched by switching the connection switching mechanism (51) so that the outdoor heat exchanger (3) functions more toward the condensation side. A condensation cycle is set and the opening AR of the first electric expansion valve (4) is increased. In addition, when one is an insufficient heating capacity signal and the other is an appropriate cooling capacity signal, or when one is an appropriate heating capacity signal and the other is an excessive cooling capacity signal, the outdoor heat exchanger (3) should function toward the evaporation side. The outdoor heat exchanger (3) in an evaporation cycle, and
The opening AR of the electric expansion valve (4) is increased.

Here, as a feature of the present invention, in the above table, when one is an insufficient heating capacity signal and the other is an excessive cooling capacity signal, and when one is an excessive heating capacity signal and the other is an insufficient cooling capacity signal, that is, the indoor unit ( When the total number of A) to (C) is insufficient for the condensation or evaporation capacity on the outdoor heat exchanger (3) side during the heating operation or the cooling operation, the first electric expansion valve (4) is opened as follows. AR and the operating capacity of the compressor (1) are controlled.

That is, when the indoor unit (A) ~ (C) is insufficient evaporating ability of the outdoor heat exchanger (3) to all heating operation or the like, as shown in the flow chart of FIG. 3, Step S ₁ From the signal of the gas-liquid differential temperature detecting means (50), it is determined whether or not the superheat degree Sh is equal to or lower than a predetermined lower limit value Shmin determined within a range where liquid compression does not occur in the compressor (1), and the overheat is determined. while the degree Sh does not reach the lower limit value, in order to function outdoor heat exchanger in step S ₂ of (3) more evaporation side, the outdoor heat exchanger by switching the connection switching mechanism (51) (3) is evaporated The first electric expansion valve (4) so that it becomes a cycle
The opening AR is controlled so as to increase. Then, if in step S _3, it is determined whether or not entered a proper condition, if not enter the proper conditions, repeat the above steps, superheat Sh reaches the lower limit Shmin in the determination of step S ₁ during which When the opening AR of the first electric expansion valve (4) reaches the fully open value ARmax, it is determined that the opening AR control of the first electric expansion valve (4) alone cannot maintain the proper condition, and the process proceeds to step S _4. ,
The operating capacity of the compressor (1) is controlled to increase.

Further, when the outdoor heat exchanger (3) lacks the condensing capacity during the total cooling operation of the indoor units (A) to (C), as shown in the flowchart of FIG.
_The control corresponding to steps S _{1 to} S ₄ in FIG. 3 is performed at ₁ ′ to S ₄ ′, and at step S ₁ ′, the supercooling degree Sc is determined from the signal of the gas-liquid differential temperature detecting means (50). If it is larger than the lower limit value Scmin, it is judged whether or not it is less than or equal to a predetermined lower limit value Scmin, and in step S2 ', the connection switching mechanism (51) is switched so that the outdoor heat exchanger (3) functions more toward the condensation side. as the outdoor heat exchanger (3) is the evaporation cycle by and while opening AR of the first electric expansion valve (4) is controlled to increase, the next step S ₃ by this regulation
Without entering the proper conditions in the determination of whether the degree of supercooling Sc in step S ₁ after repeated control reaches a lower limit Scmin, the opening AR is fully opened value ARMAX, step S
Control proceeds to ₄ ', and the operating capacity of the compressor (1) is increased.

In the above flow, according to the invention of claim (1), when the high pressure Tc and the low pressure Te are both higher than the proper ranges in step S ₂ ′, the outdoor heat exchanger (heat source side heat exchanger) (3) is turned on. Refrigerant action control means (52) for controlling the condensation action direction is configured, and in step S ₄ ′, the refrigerant action control means (52) receives the outputs of the refrigerant action control means (52) and the gas-liquid differential temperature detection means (50). 52) When the supercooling degree Sc of the refrigerant reaches the lower limit value Scmin during the control by 52) or the first
The opening AR of the electric expansion valve (flow control mechanism) (4) is the fully open value AR
A capacity control means (53) is arranged to change the operating capacity of the compressor (1) to the increasing side when it reaches the maximum.

Further, in the present invention (2), the step S _2, when the high pressure Tc and low Te is lower than both the proper range, the refrigerant acts to control the heat source-side heat exchanger (3) in the vaporisation direction The control means (52) is constituted, and step S
₄ , the refrigerant action control means (52) and the gas-liquid differential temperature detection means (50) receive the outputs, and the refrigerant action control means (5)
When the superheat degree Sh of the refrigerant reaches the deadline value Shmin during the control by 2) or the opening degree AR of the first electric expansion valve (4) is the fully open value.
A capacity control means (53) is arranged to change the operating capacity of the compressor (1) to the increasing side when ARmax is reached.

Therefore, in the invention of claim (1), the high pressure sensor (P
High pressure value Tc and low pressure sensor (Pe) detected in c)
When the low-pressure value Te detected at 1 is higher than the predetermined proper range and the excess heating capacity signal and the insufficient cooling capacity signal are obtained, for example, during the total cooling operation of the device, the outdoor heat exchanger (3) If the condensation capacity of is insufficient,
The opening control AR of the first electric expansion valve (4) is controlled by the refrigerant action control means (52) in a direction to increase the condensation capacity of the outdoor heat exchanger (3), that is, the opening AR is increased. However, when the proper condition is not reached even by adjusting the opening degree and the supercooling degree Sc reaches the lower limit value Scmin during that time, and the opening degree AR cannot be further increased, or when the opening degree AR itself becomes the full opening value ARmax, the capacity control is performed. By the means (53), the operating capacity of the compressor (1) is controlled to increase, so that the refrigerant flow rate increases and the capacity of the outdoor heat exchanger (3) increases. Therefore, it is possible to effectively prevent the balance between the cooling capacity and the heating capacity from being disturbed during the operation of the device, and to maintain a comfortable air-conditioning feeling.

Further, in the invention of claim (2), when the insufficient heating capacity signal and the excessive cooling capacity signal are obtained, for example, during the total heating operation of the indoor units (A) to (C), the outdoor heat exchanger (3 ), The refrigerant action control means (52) causes the opening degree AR of the first electric expansion valve (4) to increase the condensing ability of the outdoor heat exchanger (3). That is, the opening AR is controlled so as to increase,
When the proper condition is not reached even by adjusting the opening degree and the superheat degree Sh reaches the lower limit value Shmin during that time, and the opening degree AR cannot be further increased, or when the opening degree AR itself reaches the fully open value ARmax, the capacity control means ( By 53), the operating capacity of the compressor (1) is controlled to increase, so that the refrigerant flow rate increases and the capacity of the outdoor heat exchanger (3) increases. Therefore, it is possible to obtain the same effect as that of the invention of claim (1).

(Effect of the invention) As described above, according to the invention of claim (1), a plurality of indoor units are connected to the outdoor unit, and each indoor unit can be individually cooled and heated so that the heat recovery type air can be operated. In the air conditioner, high pressure and low pressure are detected in the discharge line and the suction line, respectively, and when both high pressure and low pressure are higher than the proper range, the flow rate control mechanism of the heat source side heat exchanger is increased so as to increase the condensing capacity. In addition to controlling the opening, the operating capacity of the compressor is increased when the degree of supercooling of the refrigerant under control reaches the lower limit value or when the opening is fully opened. Even when the condensing capacity of the heat source side heat exchanger is insufficient during operation, the required amount of refrigerant flow to the heat source side heat exchanger is secured,
The balance of air conditioning capacity can be maintained.

Further, according to the invention of claim (2), in the heat recovery type air conditioner similar to the above, when the high pressure and the low pressure are both lower than the proper range, the evaporation capacity of the heat source side heat exchanger is increased. In order to control the opening of the flow rate control mechanism so as to increase the operating capacity of the compressor when the degree of superheat of the refrigerant under control reaches the lower limit value or when the opening is fully opened. , Even when the indoor unit has a shortage of evaporation capacity of the heat source side heat exchanger during total heating operation, the required amount of refrigerant flow to the heat source side heat exchanger is secured and the balance of the cooling and heating capacity can be maintained. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 and the following shows an embodiment of the present invention, FIG. 2 is a refrigerant system diagram thereof, FIG. 3 is a flow chart showing the control contents when both high pressure and low pressure are low, and FIG. It is a flowchart figure which shows the control content when both are low. (1) ... compressor, (3) ... outdoor heat exchanger (heat source side heat exchanger), (4) ... first electric expansion valve (flow control mechanism),
(6) ... Second electric expansion valve (pressure reducing mechanism), (7) ... Indoor heat exchanger (use side heat exchanger), (11) ... Refrigerant piping, (1)
1b) ... Gas line, (11c) ... Discharge line, (11
d) ... Suction line, (12) ... Refrigerant circuit, (50) ... Gas-liquid differential temperature detecting means, (51) ... Connection switching mechanism, (52) ...
Refrigerant action control means, (53) ... Capacity control means, (X) ...
Outdoor unit, (A) to (C) ... Indoor unit.

Claims (2)

[Claims] Claim: What is claimed is: 1. A variable capacity compressor (1), a heat source side heat exchanger (3), and a flow rate control mechanism (4) having a refrigerant flow rate adjusting function and a pressure reducing function for the heat source side heat exchanger (3). A plurality of indoor units (A) to (C) having a use side heat exchanger (7) and a pressure reducing mechanism (6) for the use side heat exchanger (7). A refrigerant circuit (12) connected in parallel with a refrigerant pipe (11) is provided, and each of the heat exchangers (3), (7) to (7) functions as an evaporation cycle or a condenser. The refrigerant line (12) of each heat exchanger (3), (7) to (7) is connected to the discharge line (11c) side and the suction side so that the refrigerant circulates in the condensation cycle. Heat recovery type equipped with a connection switching mechanism (51) for individually switching to the line (11d) side In the air conditioner, a high pressure detecting means (Pc) which is arranged in the discharge line of the refrigerant circuit (12) and detects a high pressure, and a low pressure detecting means (Pe) which is arranged in the suction line (11d) and detects a low pressure. , A gas-liquid differential temperature detecting means (50) for detecting the degree of supercooling of the refrigerant in the heat source side heat exchanger (3), and the high pressure detecting means (P
c) and the output of the low pressure detection means (Pe), the refrigerant action control means (52) for controlling the heat source side heat exchanger (3) in the condensation action direction when both the high pressure and the low pressure are higher than the proper range. ) And the outputs of the refrigerant action control means (52) and the gas-liquid difference temperature detection means (50), and when the degree of supercooling of the refrigerant reaches the lower limit value during the control by the refrigerant action control means (52), or A heat recovery type air comprising: a capacity control means (53) for changing the operating capacity of the compressor (1) to an increasing side when the opening degree of the flow rate control mechanism (4) is fully opened. Operation control device for the harmony device. 2. A variable capacity compressor (1), a heat source side heat exchanger (3), and a flow rate control mechanism (4) having a function of adjusting the refrigerant flow rate to the heat source side heat exchanger (3) and a pressure reducing function. A plurality of indoor units (A) to (C) having a use side heat exchanger (7) and a pressure reducing mechanism (6) for the use side heat exchanger (7). A refrigerant circuit (12) connected in parallel with a refrigerant pipe (11) is provided, and each of the heat exchangers (3), (7) to (7) functions as an evaporation cycle or a condenser. The refrigerant line (12) of each heat exchanger (3), (7) to (7) is connected to the discharge line (11c) side and the suction side so that the refrigerant circulates in the condensation cycle. Heat recovery type equipped with a connection switching mechanism (51) for individually switching to the line (11d) side In the air conditioner, a high pressure detecting means (Pc) which is arranged in the discharge line of the refrigerant circuit (12) and detects a high pressure, and a low pressure detecting means (Pe) which is arranged in the suction line (11d) and detects a low pressure. A gas-liquid differential temperature detecting means (50) for detecting the degree of superheat of the refrigerant in the heat source side heat exchanger (3), and the high pressure detecting means (Pc)
And refrigerant action control means (52) for controlling the heat source side heat exchanger (3) in the evaporative action direction when the high pressure and the low pressure are both lower than the proper range by receiving the output of the low pressure detection means (Pe). When the superheat of the refrigerant reaches the lower limit value during the control by the refrigerant action control means (52) by receiving the outputs of the refrigerant action control means (52) and the gas-liquid differential temperature detection means (50), or the flow rate control mechanism. A heat recovery type air conditioner comprising: a capacity control means (53) for changing the operating capacity of the compressor (1) to an increasing side when the opening degree of (4) is fully opened. Operation control device.