JPH04236047A - Multiroom type air-conditioning method - Google Patents

Abstract

PURPOSE:To obtain fully cooling-and-heating performance desired, by a method wherein the distribution of a refrigerant is well balanced between indoor machines and an outdoor machine even if cooling and heating operations are simultaneously performed for the indoor machines. CONSTITUTION:When cooling and heating operations are simultaneously performed for indoor machines 2a, 2b, a capacity of a compressor 7 and a fan speed are controlled so that a suction pressure and discharge pressure of the compressor 7 are within the range of presetting and a capacity of an outdoor heat-exchanger 9 is made minimum by the combinations of variables to be controlled for the capacity of the compressor and the fan speed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the control of the outdoor unit of a multi-type air conditioner, and more particularly to a multi-type air conditioning system that controls compressor capacity and fan speed of an outdoor heat exchanger.

0002

BACKGROUND ART FIG. 1 is a refrigerant system diagram showing a conventional multi-type air conditioning system and a multi-type air conditioning system according to the present invention. In the figure, 1 is an outdoor unit, 2a and 2b are indoor units, and 4, 5, and 6 are refrigerant pipes. , 4 is a refrigerant discharge pipe, 5 is a refrigerant suction pipe, and 6 is a refrigerant liquid pipe. Inside the outdoor unit 1,
7 is a compressor with capacity control, 8 is an accumulator, 9 is an outdoor heat exchanger, 10 is an outdoor blower, 11 is a bidirectional outdoor throttle device, 13 is a solenoid valve and a check valve on the refrigerant discharge pipe 4 , 14 and 15 are electromagnetic valves and check valves on the refrigerant suction pipe 5, 30 is a discharge pressure sensor that measures the discharge pressure, 31 is a suction pressure sensor that measures the suction pressure, and 32 is a temperature sensor that measures the outside air temperature. be. On the other hand, the indoor units 2a, 2
In b, 20a, 20b are indoor heat exchangers, 21a,
21b is a bidirectional indoor diaphragm device, 22a, 22b and 2
3a and 23b are a solenoid valve and a check valve on the refrigerant discharge pipe 4;
4a, 24b and 25a, 25b are electromagnetic valves and check valves on the suction pipe 5.

FIG. 3 is a block diagram showing an indoor unit controller 40 that controls the operation of the compressor 7 and fan 10. Reference numeral 41 indicates the discharge and suction pressures of the compressor 7 according to a program stored in a read-only memory 42. a microprocessor as a calculation means for calculating a predicted value, calculating a deviation between this predicted value and a target value, calculating an evaluation value from the deviation, and performing other data calculations and processing; 43 is a random access memory for storing data; 44 is a discharge memory; An analog input section that takes in each analog output from the pressure sensor 30, suction pressure sensor 31, and temperature sensor 32; 45 is the indoor unit 2a;
, 2b, a digital input section that takes in start/stop inputs, etc., 4
6 is a fan speed control section, 47 is a compressor capacity control section, 48 is a digital output section, 38 is a fan inverter that controls the fan speed in response to a fan speed control signal, and 39 is a compressor in response to a compressor capacity control signal. This is a compressor inverter that controls the capacity of the compressor.

Next, the operation will be explained. When the indoor units 2a and 2b are stopped, they are fully closed together with the solenoid valves 24a and 24b and the indoor throttle devices 21a and 21b, and when they start operating, they transmit an operation start signal to the outdoor unit 1 (
(transmission means not shown). Also, during cooling operation, the solenoid valves 24a and 24b are opened and the solenoid valves 22a and 22b are closed.
By setting the indoor expansion devices 21a and 21b to a predetermined opening degree for cooling, the indoor expansion devices 21a and 21b expand the condensed refrigerant liquid flowing from the refrigerant liquid pipe 6, and the indoor heat exchangers 20a and 20b expand the condensed refrigerant liquid flowing from the refrigerant liquid pipe 6. It is evaporated to produce a cooling effect, and is returned to the refrigerant suction pipe 5 via the electromagnetic valves 24a and 24b. On the other hand, during heating operation, the solenoid valves 22a and 22b are opened, the solenoid valves 24a and 24b are closed, and the indoor diaphragm devices 21 and 21 are closed.
a and 21b are fully opened. As a result, the refrigerant discharge pipe 4
The discharged gas flowing further enters the indoor heat exchanger 20 via the electromagnetic valves 22a and 22b, where it is condensed to produce a heating effect, and returns to the refrigerant liquid pipe 6 via the indoor expansion devices 21a and 21b. On the other hand, the outdoor unit 1 starts operation upon receiving the operation start signal from the indoor units 2a and 2b, but depending on the state of the discharge pressure and suction pressure, the outdoor heat exchanger 9 is set to the evaporator mode or the condenser mode. drive. When the evaporator mode is set, the solenoid valve 14 is opened, the solenoid valve 12 is closed, and the outdoor throttle device 11 is set to a predetermined opening degree for the evaporator, so that the discharge gas from the compressor 7 is discharged as a refrigerant. The condensed refrigerant liquid that flows into the piping 4 and flows from the refrigerant liquid piping 6 is throttled and expanded by the outdoor expansion device 11, evaporated by the outdoor heat exchanger 9, and then transferred to the accumulator via the solenoid valve 14 and check valve 15. 3, and after being separated into gas and liquid, it returns to the compressor 7. On the other hand, when the outdoor heat exchanger 9 is set to the condenser mode, the solenoid valve 12 is opened, the solenoid valve 14 is closed, and the outdoor throttle device 11 is fully opened, so that the discharged gas from the compressor 7 is transferred to the refrigerant. It flows out into the discharge pipe 4 and condenses in the outdoor heat exchanger 9 via the solenoid valve 12 and check valve 13, and then returns to the refrigerant liquid pipe 6 via the outdoor expansion device 11. Based on the basic operation described above, the outdoor unit 1 controls the capacity of the compressor 7 and performs outdoor heat exchange based on the discharge pressure and suction pressure that change depending on the operating conditions of the indoor units 2a and 2b using the outdoor unit controller. Selects the mode of the device 9 and controls the air speed of the outdoor fan. This control operation is shown in Figure 5.
This will be explained based on the flowchart.

[0005] First, the outdoor unit 1 is powered on, and
When the outdoor unit controller 40 starts, it checks whether the indoor units 2a, 2b are started or stopped based on the input status from the digital input section 45 (step S).
T50), when there is a start/stop trigger, the indoor units 2a,
2b has all stopped (step ST51). In the case of a complete stop (in this embodiment, both indoor units 2a and 2b stop), the outdoor unit 9
Since it is no longer necessary to operate the The output unit 48 performs processing to stop the compressor 7 (step ST52), and returns to step ST50. Further, if the indoor units 2a, 2b are not fully stopped in step ST51, it is checked whether the indoor units 2a, 2b are in the first operation (step ST53). For the first operation, Qcomp is controlled to m% and AKe is controlled to a predetermined capacity of n%, and the compressor 7 is started. This is because unless the compressor 7 is started, the discharge pressure Pd will not start to rise and the suction pressure Ps will not start to fall.
These values are set because changes in Pd and Ps cannot be observed, and m and n values are set as small as possible to avoid abnormal pressure. Next, a t1 timer is started (step ST55), and the process returns to step ST50. In addition, in step ST53, if it is not the first operation, Pd and Ps have already reached the pressure during a certain operation, so step ST54 is bypassed, and step ST54 is bypassed.
Go to T55. Here, t1 timer is indoor unit 2
After a change occurs in each control amount such as starting and stopping of the compressor capacity control section 47 and fan speed control section 46 of the outdoor unit 1, the result becomes a change in the discharge pressure Pd and the suction pressure Ps. It is a time constant until it appears, and from step ST50 to step S
At T56, the next control is suspended until time t1 has elapsed. Next, when time t1 has elapsed, pressure data Pd from each sensor 30, 31 is input to the analog input section 44.
, Ps are input (step ST57). Next, in steps ST58 and ST59, it is checked whether Pd and Ps are within a predetermined range, and if they are, there is no need to change the compressor capacity control or fan speed control, and the outdoor unit 1 is in good condition. It is assumed that the operating state continues, and the process returns to step ST55. Normally, in an air conditioner using R-22 as a refrigerant, PdH=22kg/cm G,
PdL=17kg/cm G, PsH=6kg/cm
G, PsL = 2 to 3 kg/cm Set to about G. If it exceeds this range, it is assumed that control is necessary and the process goes to step ST60. Here, the preset Figure 4
An appropriate combination of Qcomp and AKe is selected from the setting data of Qcomp and the current compressor capacity and fan speed. That is, the current compressor capacity is Qi, and the fan speed is A.
Kj, and Qi+1 and AKj+1 respectively one step above.
, one step lower is Qi-1, AKj-1, then Qc
A maximum of nine combinations of omp and AKe are possible. Next, Q
The control amount from the current value for comp, AKe is calculated using equation 1.
The calculation is performed according to the following (step ST61).

[0006]

[Math 1]

[0007] Next, pressure changes are calculated using Equation 2 for the control amounts ΔQcomp and ΔAKe, and predicted pressure values Pd* and Ps* after control are calculated from this (step ST62). Here, a, b, c, and d are gains.

[0008]

[Math 2]

Next, these predicted values Pd*, Ps
* High pressure setting target value Pd obtained from equation 3
θ and the deviation A from the low pressure pressure setting target value Ps θ,
Calculate based on number 4.

0010

[Math 3]

[0011]

[Math 4]

Here, the coefficient η is 0≦η≦1, and the coefficient ζ
is 0≦ζ≦1, and η+ζ=1, and the high pressure side,
Indicates the priority of the low pressure side. Here, the combination of ΔQcomp and ΔAKe that results in the minimum value of deviation A is selected as the desired control amount (step ST63). From the above, Δ
Find Qcomp, ΔAKe and calculate the current value Qcomp, A
Qcomp is outputted from the compressor inverter 39 via the compressor capacity control section 47, and AKe is outputted from the fan speed control section 46.
is output from the fan inverter 38 (step ST64). After this, the process returns to step ST55, and these cycles are repeated thereafter.

[0013]

[Problems to be Solved by the Invention] Since the conventional multi-type air conditioning system is as described above, the suction pressure of the compressor 7,
Even if the discharge pressure falls within the set range, the fan speed may become excessive, and if cooling and heating operations are performed at the same time, the outdoor heat exchanger 9, indoor heat exchanger 20a,
20b, and if the outdoor heat exchanger 9 is an evaporator, the indoor heat exchanger 20a, 20b
However, when the outdoor heat exchanger 9 is a condenser, the heating capacity of the indoor heat exchangers 20a and 20b is insufficient.

[0014] This invention was made to solve the above-mentioned problems, and even when cooling and heating operations are performed at the same time, the suction pressure and discharge pressure of the compressor can be operated within the set values. Another object of the present invention is to obtain a multi-air conditioning system that can obtain a predetermined cooling capacity or heating capacity on the indoor unit side while minimizing the capacity of the outdoor heat exchanger.

[0015]

[Means for Solving the Problems] The multi-type air conditioning system according to the present invention is capable of controlling the compressor capacity based on the combination of compressor capacity and fan speed control amounts when cooling and heating operations are performed simultaneously in an indoor unit. The compressor capacity and fan speed are controlled so that the suction pressure and discharge pressure of the compressor are within the set range, and the outdoor heat exchanger has the minimum required capacity.

[0016]

[Operation] The multi-type air conditioning system of this invention reduces the outdoor heat exchanger capacity to the minimum required capacity when the suction pressure and discharge pressure of the compressor are within the set range and when cooling and heating are operated simultaneously. The compressor capacity and fan speed are controlled to ensure that even when cooling and heating operations are performed at the same time,
To prevent imbalance in refrigerant distribution between an outdoor unit side and an indoor unit side, and to obtain predetermined cooling capacity and heating capacity on the indoor unit side.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a multi-type air conditioning system according to the present invention, which employs the same configuration as the conventional system, and the present invention implements air conditioning control in accordance with the flowchart shown in FIG. 2 in this block diagram. . In addition,
In FIG. 2, the processes in steps ST50 to ST64 are the same as those in the conventional process, so a redundant explanation thereof will be omitted here.

Next, the operation will be explained. The operations in the refrigerant system and the outdoor unit controller 40 are the same as conventional ones, and therefore in FIG.
Since the steps up to ST62 are the same as those in FIG. 5, the redundant explanation will be omitted. Now, in the control according to the present invention, the control amount of the compressor capacity and the control amount of the fan speed are determined by calculations in steps ST70 to ST72 shown in FIG. 2, and the compressor capacity and fan speed to be operated are determined. That is, Figure 2
In the calculations up to step ST62, a maximum of nine evaluation values of pressure deviation A are obtained, and then it is determined whether cooling and heating are being operated simultaneously (step ST70), and if cooling and heating are being operated simultaneously, Therefore, each of these evaluation values is compared, and n patterns (1≦n<9) are created in order from the smallest value.
is selected, and the 9-n pattern is excluded from the selection (step ST71). As a result, the resulting combination is, for example, n=
3, it becomes as shown in Equation 5.

[0019]

[Math 5]

Next, in the above combination, AKj-1
, AKj are compared, the smaller value is selected, and one combination including the smaller value is determined (step ST7
2). That is, if AKj-1 <AKj, Equation 6 is obtained.

[0021]

[Math 6]

[0022] Furthermore, if the values of ΔAKe are equal,
One combination with the minimum evaluation value A is selected from the above n combinations.

[0023]

As described above, according to the present invention, when cooling and heating operations are performed simultaneously in an indoor unit, the suction pressure of the compressor can be adjusted based on the combination of the control amount of the compressor capacity and fan speed. Since the compressor capacity and fan speed are controlled so that the discharge pressure is within the set range and the outdoor heat exchanger has the minimum required capacity, the refrigerant distribution amplifier between the indoor unit and the outdoor unit is controlled. This has the effect of preventing imbalance from occurring and providing optimal cooling and heating capacity on the indoor unit side.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a refrigerant system implementing the present invention and a conventional multi-type air conditioning system.

FIG. 2 is a flowchart showing the execution procedure of the multi-type air conditioning system of the present invention.

FIG. 3 is a block diagram showing an outdoor unit controller.

FIG. 4 is a table showing combinations of setting data of compressor capacity and fan speed.

FIG. 5 is a flowchart showing the execution procedure of a conventional multi-type air conditioning system.

[Explanation of symbols]

1 Outdoor unit 2a Indoor unit 2b Indoor unit 4 Refrigerant discharge piping 5 Refrigerant suction piping 6 Refrigerant liquid piping 7 Compressor 9 Outdoor heat exchanger 10 Fan 30 Discharge pressure sensor 31 Suction pressure sensor 41 Computing means (CPU) In the figure, The same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Corporation Representative Patent attorney Hiroaki Tazawa (2 others)

Claims (1)

[Claims] Claim 1: An outdoor unit having a capacity-controllable compressor, a speed-controllable fan, and an outdoor heat exchanger that can be used as an evaporator or a condenser, and a refrigerant discharge pipe, a refrigerant suction pipe, and In a multi-type air conditioning system that includes a plurality of indoor units connected via refrigerant liquid piping, and selectively performs cooling and heating operations for each of the indoor units by controlling the operation of the outdoor unit, Detecting the suction pressure and discharge pressure of the compressor using a suction pressure sensor and a discharge pressure sensor,
From a combination of these detected values and multiple compressor capacities and fan speeds limited to a preset range, the calculation means calculates predicted values for the suction pressure and discharge pressure after control, and calculates the predicted values for each cooling and heating operation. are performed at the same time, an evaluation value is obtained from the deviation between the predicted values of the suction pressure and discharge pressure and the set target values of the low pressure and high pressure, and the fan speed is minimized from the plurality of evaluation values. A multi-type air conditioning system characterized by determining a combination of compressor capacity and fan speed, and controlling each cooling and heating capacity according to this determination.