JPH081343B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention has a compressor with a variable compression capacity, and
The present invention relates to a so-called multi-type air conditioner configured by connecting a plurality of indoor units.

(Prior Art) As a conventional example of the above-mentioned multi-type air conditioner, for example, an apparatus described in JP-A-62-49146 can be cited. In the apparatus, the saturated condensing temperature is detected, and the operating frequency of the inverter-controlled compressor is adjusted according to whether it is in the proper range or not. When a change occurs in the number of indoor units to be operated, for example, the driving of the compressor is newly started at an initial frequency preset corresponding to the total of the rated capacities of the operating indoor units, afterwards,
After the changed refrigerant circulation cycle is stabilized, control is performed again by correcting the operating frequency based on the saturated condensation temperature.

(Problems to be Solved by the Invention) However, in the above-mentioned device, when the number of indoor units to be operated is changed, there is a problem that air conditioning comfort is easily impaired on the indoor side where the operation is continued. For example,
Even if the room temperature approaches the set temperature by continuing the operation until then, and the operating state at that time is a low load state that is significantly different from the operating state when calculating the rated capacity, This is because the operation frequency is uniformly changed to a preset operating frequency, so that the refrigerant flow rate becomes excessively large, and as a result, the blowout temperature suddenly changes to give an uncomfortable feeling.

The present invention has been made in view of the above, and an object thereof is to provide an air conditioner that can reduce discomfort when the number of operating indoor units is changed.

(Means for Solving the Problem) Therefore, the air conditioner of the present invention has a plurality of indoor units each having an indoor heat exchanger 23 in an outdoor unit X having a compressor 1 having a variable compression capacity and an outdoor heat exchanger 10. Unit A ~
To connect D in parallel with each other, and to circulate between the indoor heat exchanger 23 and the outdoor heat exchanger 10 in the indoor unit A ... In which the refrigerant discharged from the compressor 1 is issuing the operation request signal. An air conditioner which is provided with operation control means 45 for controlling and controlling the compressor 1 with a compression capacity according to the total load of the indoor units A ... Issuing the operation request signal. As shown in the figure, pressure detection means for detecting the pressure in the indoor heat exchanger 23 in which the refrigerant is further circulated.
When the number of the indoor heat exchangers 23 in which the refrigerant circulates is changed, the pressure of the compressor 1 of the compressor 1 is adjusted so that the pressure detected by the pressure detecting unit 30 after the number of units is changed is close to the pressure detected before the change. Change compression capacity control means for controlling compression capacity
The operation control means 45 has 50.

(Operation) In the above air conditioner, when the number of the indoor heat exchangers 23 in which the refrigerant circulates is changed, the pressure in the indoor heat exchanger 23 in which the refrigerant continuously circulates is substantially the same before and after the change. Switch to control. Therefore, since the operation in which the condensation temperature or the evaporation temperature is changed in the indoor heat exchanger 23 during the continuous operation is performed, a sudden change in the blowout temperature does not occur, thereby reducing the discomfort of the user. You can

(Example) Next, a specific example of the air conditioner of the present invention will be described in detail with reference to the drawings.

First, FIG. 2 shows a refrigerant circuit diagram of an air conditioner in one embodiment of the present invention. In FIG. 2, X is an outdoor unit, and this outdoor unit X has four indoor units A to D is connected.

The outdoor unit X has a compressor 1, and a discharge pipe 2 and a suction pipe 3 of the compressor 1 are connected to a four-way switching valve 4, and the four-way switching valve 4 further includes a first gas. The pipe 5 and the second gas pipe 6 are connected. The compressor 1 has an inverter 7 for controlling its rotation speed, that is, compression capacity, a check valve 8 is provided in the discharge pipe 2, and an accumulator 9 is provided in the suction pipe 8. It is installed. The first gas pipe 5 is
The second gas pipe 6 is connected to the outdoor heat exchanger 10, the second gas pipe 6 is connected to the header 11, and the gas shutoff valve 12 is provided midway. An outdoor fan 13 is attached to the outdoor heat exchanger 10 and a liquid pipe 14 is further connected to the outdoor heat exchanger 10. The dryer pipe 15 and the first electric expansion are sequentially connected to the liquid pipe 14 from the outdoor heat exchanger 10 side. A valve 16, a liquid receiver 17, and a liquid closing valve 18 are interposed. The tip of the liquid pipe 14 is provided with a plurality of second electric expansion valves 19 ...
While branching to the liquid branch pipe 20 ...
Four gas branch pipes 22..22 provided with mufflers 21 .. are respectively connected to 11, and an indoor heat exchanger 23 (indoor chamber) is provided between these gas branch pipes 22 and each of the liquid branch pipes 22. (Unit A is shown in the figure)
Are connected in parallel with each other. Each indoor unit A to D is composed of the indoor heat exchanger 23 and the indoor fan 25, respectively.

Further, in the above apparatus, a pressure sensor (pressure detecting means) 30 is attached to the second gas pipe 6 to detect the refrigerant pressure inside the gas pipe 6.

Next, in the air conditioner having the above configuration, the refrigerant circulation control during the heating operation will be described. In this operation, the four-way switching valve 4 is positioned at a switching position indicated by a solid line in the figure, and refrigerant discharged from the compressor 1 is passed through the four-way switching valve 4 and the second gas pipe 6 to each indoor heat exchanger. After condensing at 23 and then evaporating in the outdoor heat exchanger 10 via the liquid pipe 14, the first gas pipe 5,
This is performed by returning the flow from the four-way switching valve 4 to the compressor 1. In this case, the degree of superheat of the evaporated refrigerant is controlled by the first electric expansion valve 16, and each second electric expansion valve 19 controls the amount of refrigerant distributed to each indoor heat exchanger 23. The heating operation in which some rooms were stopped is performed by the indoor unit A in the stopped room.
The second electric expansion valve 19 on the side is set to a stop opening degree (an opening degree capable of flowing a small amount of refrigerant corresponding to natural heat radiation in order to prevent liquid return to the compressor 1).

On the other hand, the cooling operation is performed by switching the four-way switching valve 4 to the switching position indicated by the broken line in the figure and circulating the refrigerant discharged from the compressor 1 from the outdoor heat exchanger 10 to each of the indoor heat exchangers 23. . At this time, the first electric expansion valve 16 is fully opened, and each second electric expansion valve 19 controls the degree of superheat of the refrigerant. The second electric expansion valve 19 on the indoor unit A ... side in the cooling stop room is fully closed.

Next, regarding the operation control in the air conditioner,
This will be described with reference to the operation control system diagram in the figure. As shown
Each of the indoor units A to D includes an indoor control device 41 (only the indoor unit A is shown), and each indoor control device 41 includes a remote controller 42 for driving operation and a room temperature detection sensor 43 for detecting the room temperature. Each is connected. Each of the operation remote controllers 42 has a cooling / heating switch, an operation switch, and a temperature setting switch for setting a desired room temperature, the operation switch is ON, and the temperature detected by the room temperature sensor 43. If the temperature does not reach the set temperature (when the indoor thermostat is ON), the heating operation request signal or the cooling operation request signal is the temperature difference signal between the detected temperature and the set temperature, depending on the switching position of the cooling / heating switch. At the same time, it is output from each indoor control device 41 to the outdoor unit X.

On the other hand, the outdoor unit X includes an outdoor control device (operation control means) 45, an inverter control device 46, and a valve control device 47, and an operation request unit grasping section 48 is provided in the outdoor control device 45. ing. The operation request unit grasping section 48 determines the indoor unit that is outputting the heating or cooling operation request signal, and when starting from the completely stopped state, or when changing the number of operating units, in any of the indoor units during operation. When changing the number of operating units by ON / OFF operation of the operation switch or switching ON / OFF of the indoor thermostat, the operation signal corresponding to the indoor unit that is outputting the operation request signal together with the start signal or the change signal is output to the above valve. Output to the control device 47. As a result, by the valve control device 47, together with the switching operation of the four-way switching valve 4 to form the refrigerant circulation path during the heating operation or the cooling operation,
The opening degree of the first and second electric expansion valves 16 and 19 is controlled.

Next, the compression capacity of the compressor 1, that is, the control of the inverter frequency will be described. For this reason, in the outdoor control device 45, the steady-state frequency control section 49 and the change-time frequency control section (change-time compression capacity control Means) 50 is provided, and at the time of start-up, the start-up signal is input to the steady-state frequency control section 49 to generate a start-up initial frequency in the steady-state frequency control section 49, This is output to the inverter controller 46, and as a result, the compressor 1 is output by the inverter controller 46 at the initial frequency.
Is started. Then, after the number of rotations corresponding to the initial frequency, in response to the change in the temperature difference signal input from the indoor control device 41 to the steady-state frequency control unit 49, for example, the load on the indoor side by PID control. A frequency corresponding to the change of the above is sequentially generated in the stationary frequency control unit 49, and the operation is continued while controlling the compression capacity of the compressor 1 at this frequency.

Then, in the middle of the operation, when the number of operating units on the indoor side is changed and the change signal is output from the operation request unit grasping section 48, the control of the compressor 1 is controlled by the change signal by the stationary frequency control section. Frequency controller when changing from 49
Switched to 50. The detection pressure signal from the pressure sensor 30 that detects the pressure inside the second gas pipe 6 is input to the change frequency control unit 50, and the detection pressure at the time when the change signal is generated is changed. The previous pressure value is first stored in the change frequency controller 50. After that, the change signal is also input to the valve control device 47 to newly add the operation or change the opening degree of the second electric expansion valve 19 corresponding to the indoor unit to be stopped. Although the internal pressure of the second gas pipe 6 also changes, the frequency controller 50 at the time of change so as to bring the pressure after the change close to the pressure value before the change.
The frequency is increased / decreased. That is, if the pressure after the change is detected as a value lower than the pressure value at the time of the change, the drive frequency until then is gradually increased, for example, at a rate of 10 Hz / minute, and the pressure value before the change is changed. Is detected as a high value, a frequency that gradually decreases the driving frequency until then is generated in the above-mentioned change-time frequency control unit 50, and the compressor 1 is changed according to this frequency. Be done. Then, after a lapse of a predetermined time from the generation of the change signal, or when the detected pressure after the change reaches the pressure value before the change by the control of the compression capacity, from the control by the change time frequency control unit 50 again, the The control is switched to the constant frequency control unit 49. Thereafter, in substantially the same manner as described above, by the steady-state frequency control unit 49, at the frequency according to the total load on the indoor side by PID control for the change in the total value of each temperature difference signal input from each indoor control device 41, While controlling the compression capacity of the compressor 1, the operation is continued until the change signal is generated again.

The discharge gas refrigerant supplied from the compressor 1 to each indoor heat exchanger 23 during the heating operation flows through the second gas pipe 6, and therefore, in the pressure sensor 30, the condensation pressure in each indoor heat exchanger 23 is increased. A pressure substantially equal to is detected. Further, during the cooling operation, the evaporative gas refrigerant returned from each indoor heat exchanger 23 to the compressor 1 flows through the second gas pipe 6, so that the pressure sensor 30 causes the evaporation pressure in each indoor heat exchanger 23 to Approximately equivalent pressure is detected. As a result of performing the above-described control at the time of change based on the detected pressure, the change in the condensation temperature or the evaporation temperature in the indoor heat exchanger 23 during the operation before and after the change is controlled to be as small as possible. Becomes For this reason, the sudden change in the blowout temperature at the time of change that has conventionally occurred is eliminated, and the user's comfort is improved. In addition, since the compression capacity is controlled according to the change in the total load on the indoor side except when changing,
During heating, when the room temperature is low, the blow-out temperature is raised to provide quick warming, and by controlling the blow-off temperature to gradually decrease as the room temperature approaches the set temperature, a more comfortable air conditioning operation is achieved. It is supposed to be done.

Although one embodiment of the present invention has been described above, the above embodiment is not intended to limit the present invention and various modifications can be made within the scope of the present invention. For example, in the above embodiment, in each indoor unit Although the configuration is such that the operation request signal is output when both the operation switch and the indoor thermostat are ON, it is also possible to generate the operation request signal when the operation switch is ON regardless of the indoor thermostat. is there.

(Effects of the Invention) As described above, in the air conditioner of the present invention, when the number of indoor heat exchangers through which the refrigerant circulates is changed, a change in the condensation temperature or the evaporation temperature in the indoor heat exchangers during continuous operation is suppressed. By changing over to the control, it is possible to suppress a sudden change in the blowout temperature, which can reduce the user's discomfort when changing the number of units, which has occurred conventionally.

[Brief description of drawings]

FIG. 1 is a functional block diagram of the present invention, FIG. 2 is a refrigerant circuit diagram of an air conditioner in one embodiment of the present invention, and FIG. 3 is an operation control system diagram of the air conditioner. X: outdoor unit, A to D ... indoor unit, 1 ...
Compressor, 10 …… Outdoor heat exchanger, 23 …… Indoor heat exchanger, 30
...... Pressure sensor (pressure detection means), 45 …… Outdoor control device (operation control means), 50 …… Change frequency control section (change compression capacity control means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-123945 (JP, A) JP 62-196542 (JP, A) JP 61-213561 (JP, A) JP 59- 104051 (JP, A) JP 58-85041 (JP, A)

Claims (1)

[Claims] A plurality of indoor units (A) each having an indoor heat exchanger (23) in an outdoor unit (X) having a compressor (1) having a variable compression capacity and an outdoor heat exchanger (10).
(D) are connected in parallel to each other, and the indoor heat exchanger (23) and the outdoor heat exchanger in the indoor unit (A) ... In which the refrigerant discharged from the compressor (1) issues an operation request signal. (10) Operation control means for controlling the compressor (1) so as to circulate between the compressor (1) and the indoor unit (A) ... Issuing the operation request signal with a compression capacity corresponding to the total load of the indoor units (A). An air conditioner comprising (45), further comprising a pressure detecting means (30) for detecting the pressure in an indoor heat exchanger (23) in which a refrigerant circulates, and an indoor heat exchanger in which a refrigerant circulates. (23) When the number of units is changed, the pressure detecting means (30) controls the compression capacity of the compressor (1) so that the detected pressure after the number change is closer to the detected pressure before the change. The operation control means (45) has a compression capacity control means (50). Air conditioner, characterized in that.