JPH10267431A - Outdoor unit for multitype heat pump type air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase of the drive force of a compressor due to the increase of a suction pressure during heating operation by a method wherein, based on the output of a suction pressure sensor to detect the pressure of a gas refrigerant sucked in a fixed volume type compressor, a flow rate regulation valve in a liquid refrigerant line connected to an outdoor heat-exchanger. SOLUTION: A suction pressure sensor 30 to detect the pressure of gas refrigerant sucked to compressors 1 and 2 is mounted in a common suction line 31 and a flow rate regulation valve 33 is located in a liquid refrigerant line 32 connected to an outdoor heat-exchanger 4. During cooling operation, according to lowering of a heating load based on the detecting value of a suction pressure sensor 30, a bypass valve 28 is opened. When a compressor 1 or 2 is stopped, a suction pressure is increased, but according to the increase of the suction pressure, the opening of a flow rate regulation valve 33 is reduced by a controller 34 and a flow rate of a liquid refrigerant flowing in the outdoor machine heat-exchanger 4 is reduced. As noted above, through lowering of a suction pressure and the decrease of the drive powers of the compressors 1 and 2, the coefficient of performance of an air conditioner is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outdoor unit of a multi-type heat pump type air conditioner having a plurality of fixed displacement compressors.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional multi-type heat pump type air conditioner. Plural units (two units are shown in the figure) of the outdoor units A and B respectively have plural units (two units in the figure) of fixed capacity type compressors 1 and 2, four-way switching valve 3, outdoor heat The exchange 4, the accumulator 18 and the like are mounted. Multiple units (only two units are shown in the figure)
An indoor heat exchanger 5 and the like are mounted on the indoor units P and Q, respectively.

The plurality of outdoor units A,
B and the plurality of indoor units P and Q are connected in parallel to the connection gas pipe 7 and the connection liquid pipe 8, respectively.

[0004] During the cooling operation of the air conditioner,
The high-temperature and high-pressure gas refrigerant discharged from the compressors 1 and 2 of each of the outdoor units A and B passes through the check valves 9 and 10 and the four-way switching valve 3 to the outdoor heat exchanger 4 as shown by solid arrows. It enters and condenses and liquefies by exchanging heat with the outside air.

The liquid refrigerant enters the connection liquid pipe 8 through the check valve 11, the receiver 12, and the liquid-side operation valve 13 and merges there, and then flows into each of the indoor units P and Q through the liquid-side operation valve 14. . After adiabatic expansion in the process of flowing through the cooling expansion valve 15, the air enters the indoor heat exchanger 5, where the indoor air is cooled to evaporate.

The gas refrigerant enters the connecting gas pipe 7 via the gas-side operation valve 16 and merges there, then flows into each of the outdoor units A and B via the gas-side operation valve 17, and the four-way switching valve 3, the accumulator 18 After that, it is branched and drawn into the compressors 1 and 2.

During the heating operation of the air conditioner, the four-way switching valve 3 is switched in the opposite direction, so that the refrigerant discharged from the compressors 1 and 2 receives the check valve 9,
10, the four-way switching valve 3, the gas-side operation valve 17, the connecting gas pipe 7, and the gas-side operation valve 16, enter the indoor heat exchanger 5 of each indoor unit P, Q, and condense by releasing heat to indoor air here. Liquefy.

The liquid refrigerant enters the outdoor units A and B via the check valve 6, the liquid-side operation valve 14, the connecting liquid pipe 8, and the liquid-side operation valve 13, and passes through the receiver 12 to the heating expansion valve 19. After adiabatic expansion in the flow process, it enters the outdoor heat exchanger 4 where it absorbs heat from outside air and evaporates. Next, the gas refrigerant is sucked into the compressors 1 and 2 via the four-way switching valve 3 and the accumulator 18.

When the air conditioning load decreases due to a decrease in the number of operating indoor units P and Q, the bypass valve 28 interposed in the capacity control hot gas bypass circuit 27 is opened, and the compressors 1, 2 Of the hot gas discharged from the compressor flows into the inlet side of the accumulator 18 via the hot gas bypass circuit 27 for capacity control, the bypass valve 28, and the fixed throttle 29, whereby the capacity of the compressors 1 and 2 is reduced.

When the air-conditioning load further decreases, the compressors 1, 2
Is stopped, then the bypass valve 28 is opened, and then one of the outdoor units A and B is stopped. When the air conditioning load increases, the capacity of the compressor is gradually increased by operating in the reverse order.

[0011]

In the above-mentioned conventional multi-type heat pump type air conditioner, during the heating operation,
If the capacity is reduced by opening the bypass valve 28 or stopping the compressor 1 or 2, the capacity of the outdoor heat exchanger 4 becomes excessive and the evaporation pressure rises. As a result, the pressure of the gas refrigerant sucked into the compressors 1 and 2, that is, the suction pressure increases, and the driving power of the compressors 1 and 2 increases, so that the coefficient of performance (COP) of the air conditioner deteriorates. There was a problem.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and a first aspect of the present invention resides in that a plurality of fixed-capacity compression units connected in parallel are connected. Heat pump including a compressor, a four-way switching valve, an outdoor heat exchanger, an accumulator, and a capacity control hot gas bypass circuit for guiding hot gas discharged from the fixed capacity compressor to the inlet side of the accumulator. In an outdoor unit of a type air conditioner, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed displacement compressor, and a flow control valve provided in a liquid refrigerant line connected to the outdoor heat exchanger And a controller that controls the suction pressure by controlling the flow rate control valve based on the detection value of the suction pressure sensor. In the outdoor unit of the formula air conditioner.

The gist of the second invention is that a plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and the fixed displacement compressor described above. In an outdoor unit of a multi-type heat pump type air conditioner having a capacity control hot gas bypass circuit that guides the discharged hot gas to the inlet side of the accumulator, the pressure of the gas refrigerant sucked into the fixed capacity type compressor is reduced. A suction pressure sensor for detecting, a plurality of parallel circuits of a fixed throttle and an electromagnetic on-off valve provided in the inlet side suction line of the accumulator and connected in series, and opening and closing the electromagnetic on-off valve by a detection value of the suction pressure sensor. And a controller for controlling the suction pressure in the outdoor unit of the multi-type heat pump type air conditioner.

The gist of the third invention is that a plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and the fixed displacement compressor described above. In an outdoor unit of a multi-type heat pump type air conditioner having a capacity control hot gas bypass circuit that guides the discharged hot gas to the inlet side of the accumulator, the pressure of the gas refrigerant sucked into the fixed capacity type compressor is reduced. A multi-type comprising a suction pressure sensor for detecting, and a controller for controlling the suction pressure by turning on / off the fan for the outdoor heat exchanger or controlling the rotation speed thereof based on a detection value of the suction pressure sensor. Located in the outdoor unit of the heat pump air conditioner.

The gist of the fourth invention is that a plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and the fixed displacement compressor described above. In an outdoor unit of a multi-type heat pump type air conditioner having a capacity control hot gas bypass circuit that guides the discharged hot gas to the inlet side of the accumulator, the pressure of the gas refrigerant sucked into the fixed capacity type compressor is reduced. With a suction pressure sensor to detect and a control valve to connect the discharge side of the fixed displacement compressor and the anti-outdoor heat exchanger side of the throttle mechanism interposed in the liquid refrigerant line connected to the outdoor heat exchanger A hot gas bypass circuit; and a controller for controlling the suction pressure by controlling the control valve based on a detection value of the suction pressure sensor. In the outdoor unit forms a heat pump type air conditioner.

The gist of the fifth invention is that a plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and the fixed displacement compressor are provided. In an outdoor unit of a multi-type heat pump type air conditioner having a capacity control hot gas bypass circuit that guides the discharged hot gas to the inlet side of the accumulator, the outdoor heat exchanger is divided into a plurality of units and connected in parallel. An electromagnetic on / off valve interposed in each of the liquid refrigerant lines connected to the divided outdoor heat exchanger, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed displacement compressor, and A multi-type heat pump comprising a controller for controlling the suction pressure by controlling on / off of the electromagnetic on-off valve based on a detection value of a pressure sensor. In the outdoor unit of the air conditioner.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. A suction pressure sensor 30 for detecting the pressure of the gas refrigerant sucked into the compressors 1 and 2 is attached to a common suction line 31 from the outlet of the accumulator 18 to branch to each of the compressors 1 and 2. Further, a flow regulating valve 33 is interposed in the liquid refrigerant line 32 connected to the outdoor heat exchanger 4.

When the detected value of the suction pressure sensor 30 is input to the controller 34, the controller 34
The suction pressure is controlled by outputting to 33 to control this opening. The other configuration is the same as that of the conventional one shown in FIG. 6, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

In the heating operation, when the bypass valve 28 is opened or the compressor 1 or 2 is stopped in response to a decrease in the heating load, the suction pressure increases. Therefore, the flow rate of the liquid refrigerant flowing into the outdoor heat exchanger 4 is reduced by reducing the opening of the flow control valve 33 in accordance with the increase in the suction pressure.

Then, the amount of heat absorbed by the outdoor heat exchanger 4 is reduced, and the evaporation pressure is reduced, so that the compressors 1, 2
The pressure of the gas refrigerant sucked into the compressor, that is, the suction pressure is reduced, and the driving power of the compressors 1 and 2 is reduced accordingly, so that the performance of the air conditioner is improved. Note that the heating expansion valve 19 is an electronic expansion valve, and this electronic expansion valve has a controller.
The output can also be changed by outputting from 34.

A second embodiment of the present invention is shown in FIG. In the second embodiment, the compressors 1 and 2
A suction pressure sensor 30 for detecting the pressure of the gas refrigerant to be sucked into the common suction line 31 is attached.

Then, the inlet side of the accumulator 18, that is, the outlet of the hot gas bypass circuit 27 and the accumulator 18
A suction line 40 connecting to the inlet of 18 is provided with a circuit 43 in which a fixed throttle 42 and an electromagnetic valve 41 are connected in series,
A circuit 46 in which a fixed throttle 44 having a larger resistance than 42 and an electromagnetic on-off valve 45 are connected in series is interposed in parallel.

When the detection value of the suction pressure sensor 30 is input to the controller 47, the controller 47
It outputs to 45 and opens and closes it to control the suction pressure. The other configuration is the same as that of the conventional one shown in FIG. 6, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

During the cooling operation or the heating operation, when the suction pressure is equal to or lower than a predetermined value, both of the solenoid on-off valves 41 and 45 are open, but the suction pressure increases and reaches the predetermined value. At this time, the electromagnetic on-off valve 45 is first closed, and then, when the suction pressure rises to the second set value, the electromagnetic on-off valve 41 is closed and at the same time the electromagnetic on-off valve 45 is opened.

As a result, the pressure loss of the gas refrigerant flowing through the suction line 40 gradually increases as the suction pressure increases, so that the pressure of the gas refrigerant drawn into the compressors 1 and 2 can be increased without increasing the degree of superheat. Can be suppressed.

A flow regulating valve and a pressure control valve are provided instead of the plural parallel circuits 43 and 46 of the fixed throttles 42 and 44 and the solenoid on-off valves 41 and 45 connected in series. The flow rate or pressure of the gas refrigerant can be reduced by controlling the opening of the regulating valve and the pressure control valve.

A third embodiment of the present invention is shown in FIG. In the third embodiment, a suction pressure sensor that detects the pressure of gas refrigerant sucked into the compressors 1 and 2
30 is attached to the common suction line 31.

When the detection value of the suction pressure sensor 30 is input to the controller 50, the controller 50 drives a motor 52 for driving an outdoor fan 51 for blowing outside air to the outdoor heat exchanger 4.
To control the suction pressure by turning on / off or controlling the number of rotations. The other configuration is the same as that of the conventional one shown in FIG. 6, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

In the heating operation, the number of revolutions of the outdoor fan 51 is reduced or stopped in accordance with the increase of the suction pressure, thereby reducing the amount of heat absorbed by the outdoor heat exchanger 4 and lowering the evaporation pressure. Therefore, an increase in suction pressure can be suppressed.

A fourth embodiment of the present invention is shown in FIG. In the fourth embodiment, a suction pressure sensor that detects the pressure of gas refrigerant sucked into the compressors 1 and 2
30 is attached to the common suction line 31. And
A hot gas bypass circuit 61 is provided for connecting the discharge sides of the compressors 1 and 2 and the liquid refrigerant line 60 on the side opposite to the outdoor heat exchanger of the expansion valve 19 for heating. A fixed throttle 63 is interposed.

When the detection value of the suction pressure sensor 30 is input to the controller 64, the controller 64 outputs the control valve 62 to open and close the control valve 62 to control the suction pressure. The other configuration is the same as that of the conventional one shown in FIG. 6, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

In the heating operation, when the suction pressure rises and reaches a predetermined value, the controller 64 outputs to the control valve 62 to open it. Then, the hot gas discharged from the compressors 1 and 2 is mixed into the liquid refrigerant flowing through the liquid refrigerant line 60 through the hot gas bypass circuit 61 and the control valve 62 and the fixed throttle 63 interposed therebetween. This is flash evaporated.

Thus, the heating expansion valve 19 chokes,
Since the evaporating pressure in the outdoor heat exchanger 4 is reduced, an increase in suction pressure can be suppressed.

A fifth embodiment of the present invention is shown in FIG. In the fifth embodiment, a suction pressure sensor that detects the pressure of gas refrigerant sucked into the compressors 1 and 2
30 is attached to the common suction line 31.

The plurality of outdoor heat exchangers 4 (2 in the figure)
Pieces), and the capacity of the divided outdoor heat exchanger 4a is 4b
These outdoor heat exchangers 4a and 4b are connected in parallel to the refrigerant circuit. The liquid refrigerant lines 73a, 73b connected to the outdoor heat exchangers 4a, 4b are provided with parallel circuits 70a, 70b of heating expansion valves 19a, 19b and check valves 11a, 11b, respectively. Parallel circuit 70a,
Electromagnetic on-off valves 71a and 71b are interposed on the liquid side of 70b, respectively.

When the detection value of the suction pressure sensor 30 is input to the controller 72, the controller 72 operates as an electromagnetic on-off valve.
The signals are output to 71a and 71b and are opened and closed. The other configuration is the same as that of the conventional one shown in FIG. 6, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

During the heating operation, when the suction pressure rises and reaches the first set value, the controller 72 outputs to the solenoid on-off valve 71b to close it, and the suction pressure further rises to the second on-off valve 71b. When the set value is reached, the electromagnetic on-off valve 71b is opened and at the same time the electromagnetic on-off valve 71a is closed. Thus, the amount of heat absorbed by the outdoor heat exchangers 4a and 4b decreases in accordance with the increase in the suction pressure, and the evaporation pressure decreases, so that the increase in the suction pressure can be suppressed.

[0038]

According to the first aspect of the present invention,
During the heating operation, when the detection value of the suction pressure sensor increases, the opening degree of the flow control valve is reduced to reduce the amount of liquid refrigerant flowing into the outdoor heat exchanger, thereby suppressing the heat absorption. As a result, an increase in the evaporation pressure can be prevented and the suction pressure of the gas refrigerant sucked into the compressor can be suppressed, thereby preventing an increase in the driving power of the compressor and improving the coefficient of performance of the air conditioner. sell.

According to the second aspect of the present invention, when the detection value of the suction pressure sensor increases, the pressure loss of the gas refrigerant sucked into the compressor can be increased by closing the solenoid on-off valve. Therefore, an increase in suction pressure can be prevented.

According to the third aspect of the present invention, when the detection value of the suction pressure sensor increases during the heating operation,
The outdoor heat exchanger fan is stopped or its rotation speed is reduced to reduce the amount of air blown to reduce the amount of heat absorbed by the outdoor heat exchanger, thereby suppressing an increase in suction pressure.

According to the fourth aspect of the present invention, when the detection value of the suction pressure sensor increases during the heating operation,
By opening the control valve and allowing the hot gas to flow into the throttle mechanism via the hot gas bypass circuit, and by choking the throttle mechanism, the amount of heat absorbed by the outdoor heat exchanger can be reduced, so that an increase in suction pressure can be suppressed.

According to the fifth aspect of the present invention, when the detection value of the suction pressure sensor increases during the heating operation,
Since the electromagnetic on-off valve is closed and a part of the split outdoor heat exchanger is stopped to reduce its capacity, an increase in suction pressure can be suppressed.

[Brief description of the drawings]

FIG. 1 is a system diagram of an outdoor unit according to a first embodiment of the present invention.

FIG. 2 is a system diagram of an outdoor unit according to a second embodiment of the present invention.

FIG. 3 is a system diagram of an outdoor unit according to a third embodiment of the present invention.

FIG. 4 is a system diagram of an outdoor unit according to a fourth embodiment of the present invention.

FIG. 5 is a system diagram of an outdoor unit according to a fifth embodiment of the present invention.

FIG. 6 is a refrigerant circuit diagram of a conventional multi-type heat pump air conditioner.

[Explanation of symbols]

 1, 2 Compressor 3 Four-way switching valve 4 Outdoor heat exchanger 18 Accumulator 27 Hot gas bypass circuit 28 Bypass valve 29 Fixed throttle 11 Check valve 19 Heating throttle mechanism 30 Suction pressure sensor 31 Common suction line 32 Liquid refrigerant line 33 Flow rate Regulator 34 Controller

Claims (5)

[Claims] 1. A plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and hot gas discharged from the fixed displacement compressor is supplied to the accumulator. In an outdoor unit of a multi-type heat pump type air conditioner having a hot gas bypass circuit for controlling capacity introduced to an inlet side, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed displacement compressor; A flow control valve provided in a liquid refrigerant line connected to the heat exchanger; and a controller for controlling the suction pressure by controlling the flow control valve based on a detection value of the suction pressure sensor. Outdoor unit of multi-type heat pump type air conditioner. 2. A plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and hot gas discharged from the fixed displacement compressor is supplied to the accumulator. In an outdoor unit of a multi-type heat pump type air conditioner having a hot gas bypass circuit for controlling capacity introduced to an inlet side, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed capacity type compressor, and the accumulator A plurality of parallel circuits of fixed throttles and solenoid on / off valves connected in series on the inlet side suction line and a controller for controlling the suction pressure by opening and closing the solenoid on / off valve based on the detection value of the suction pressure sensor. An outdoor unit of a multi-type heat pump type air conditioner characterized by being provided. 3. A plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and hot gas discharged from the fixed displacement compressor is supplied to the accumulator. In an outdoor unit of a multi-type heat pump type air conditioner having a hot gas bypass circuit for controlling capacity introduced to an inlet side, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed capacity compressor; An outdoor unit for a multi-type heat pump type air conditioner, comprising: a controller for controlling the suction pressure by controlling the on / off of the fan for the outdoor heat exchanger or the rotation speed thereof based on a detection value of a pressure sensor. 4. A plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and hot gas discharged from the fixed displacement compressor is supplied to the accumulator. In an outdoor unit of a multi-type heat pump type air conditioner having a hot gas bypass circuit for controlling capacity introduced to an inlet side, a suction pressure sensor for detecting a pressure of gas refrigerant sucked into the fixed displacement compressor; A hot gas bypass circuit with a control valve for connecting the discharge side of the displacement type compressor and the anti-outdoor heat exchanger side of the throttle mechanism interposed in the liquid refrigerant line connected to the outdoor heat exchanger; and the suction pressure And a controller for controlling the suction pressure by controlling the control valve according to the detection value of the sensor. Outside unit. 5. A plurality of fixed displacement compressors connected in parallel, a four-way switching valve, an outdoor heat exchanger, an accumulator, and hot gas discharged from the fixed displacement compressor is supplied to the accumulator. In an outdoor unit of a multi-type heat pump type air conditioner having a hot gas bypass circuit for controlling capacity introduced to the inlet side, the outdoor heat exchanger is divided into a plurality of units and connected to a split outdoor heat exchanger which is connected in parallel. An electromagnetic opening / closing valve interposed in each of the liquid refrigerant lines, a suction pressure sensor for detecting the pressure of the gas refrigerant sucked into the fixed displacement compressor, and the electromagnetic opening / closing based on a detection value of the suction pressure sensor. An outdoor unit for a multi-type heat pump type air conditioner, comprising: a controller for controlling on / off of a valve to control a suction pressure.