JPH04236048A - Multiroom type air-conditioner - Google Patents

Abstract

PURPOSE:To obtain the title air-conditioner whereby when indoor machine operation modes are only a heating mode, a compressor is run while a suction pressure and discharge pressure of a compressor are kept within a range of presetting, and heating performance on a capacity of the compressor is sufficiently performed by making maximum a capacity of an outdoor heat-exchanger, and thus the heating performance specified for each indoor machine can be obtained. CONSTITUTION:In a step, ST16, the case where all of indoor machines are operated in a cooling cycle or they are simultaneously operated in the cooling cycle and a heating cycle, is distiguished from the case where they are operated in the heating cycle only. In the case of the former, the control thereof is the same as a usual method, and in the case of the latter, capacity of a compressor and a fan speed are controlled so that a suction pressure and discharge pressure of the compressor are within a range of presetting and a capacity of an outdoor heat-exchanger is made maximum by combinations of variables to be controlled for both the capacity of the compressor and the fan speed for an outdoor fan, through steps, ST16 to ST18.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention consists of a plurality of indoor units connected to one indoor unit, and is capable of controlling the capacity of the compressor and the fan speed of the outdoor heat exchanger in the outdoor unit. The present invention relates to a multi-type air conditioner.

0002

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional multi-type air conditioner. In the figure, 1 is an outdoor unit; 2a is an outdoor unit;
, 2b are indoor units connected to outdoor unit 1, 4
, 5 and 6 are refrigerant pipes connecting the outdoor unit 1 and the indoor units 2a and 2b, 4 is a discharge pipe, 5 is a suction pipe, and 6 is a liquid pipe.

In the outdoor unit 1, 7 is a compressor whose capacity can be controlled, and its output side is connected to the discharge pipe 4. 8 is an accumulator arranged on the input side of the compressor 7, 12,1
3 is a solenoid valve and a check valve provided on the output side of the compressor 7;
9 is an outdoor heat exchanger; 10 is an outdoor fan whose fan speed can be controlled for heat radiation or heat seeking from the outdoor heat exchanger 9; 11 is an outdoor throttling device that controls the refrigerant flowing in and out of the outdoor heat exchanger 9;
4 and 15 are electromagnetic valves and check valves that send refrigerant from the outdoor heat exchanger 9 to the accumulator 8.

30 is a discharge pressure sensor that detects the discharge pressure of the compressor 7; 31 is a suction pressure sensor that detects the suction pressure of the compressor 7; 32 is a temperature sensor that detects the outside air temperature;
0 is the outdoor unit controller, and the discharge pressure sensor 30
, controls the capacity of the compressor 1 and the fan speed of the outdoor fan 10 based on the detected values of the suction pressure sensor 31 and the temperature sensor 32, and also performs predetermined control on other parts.

[0005] In the indoor units 2a and 2b, 20a
, 20b are indoor heat exchangers, 21a and 21b are indoor throttling devices that allow refrigerant to enter and exit the indoor heat exchangers 20a and 20b, and 22a, 22b and 23a and 23b are discharge pipes 4.
24a, 24b and 25a, 25b are solenoid valves and check valves that supply the refrigerant from the indoor heat exchangers 20a, 20b to the suction pipe 5. It is a stop valve.

FIG. 3 is a block diagram showing the configuration of the outdoor unit controller 40. In the figure, 41 is a CPU.
, 42 is a ROM in which programs are stored, 43 is a RAM in which calculation data is stored, 44 is a discharge pressure sensor 30,
An analog input section 45 receives detection signals from the suction pressure sensor 31 and the temperature sensor 32, and numeral 45 indicates the indoor unit 2a, 2.
46 is a fan speed control section that controls the fan speed; 47 is a compressor capacity control section that controls the capacity of the compressor 7; 48 is a compressor; 1 is a digital output section that outputs a stop signal; 38 is a fan speed control section 46;
An inverter 39 controls the outdoor fan 10 according to a fan speed control signal from the compressor capacity control unit 47.
An inverter 49 controls the compressor 7 according to a capacity control signal from the inverter 49, and a bus line 49 connects the CPU 41 and each part.

FIG. 4 is a flowchart showing the control of the outdoor unit controller 40.

Next, the operation will be explained.

When the indoor units 20a, 20b start operating, an operation start signal is transmitted to the outdoor unit controller 40 via a transmission means (not shown).

During cooling operation, the solenoid valves 24a, 24b and the check valves 25a, 25b are opened, and the solenoid valves 22a, 22 are opened.
b and the check valves 23a and 23b are closed. Further, the indoor diaphragm devices 21a and 21b are set to a predetermined opening degree for cooling. After the condensed refrigerant liquid flowing from the outdoor unit 1 through the liquid pipe 6 is throttled and expanded by the indoor expansion devices 21a and 21b,
It is supplied to indoor heat exchangers 20a and 20b. The refrigerant liquid evaporates here, removes heat from the room, and exerts a cooling effect.
It is sucked into the suction pipe 5 through 5b and returns to the outdoor unit 1.

During heating operation, the solenoid valves 22a, 22b and check valves 23a, 23b are opened, and the solenoid valves 24a, 24b and check valves 25a, 25b are closed. In addition, the indoor diaphragm devices 21a and 21b are fully opened. The refrigerant gas flowing from the outdoor unit 1 through the discharge pipe 4 is supplied to the solenoid valve 22a,
22b and check valves 23a, 23b to the indoor heat exchangers 20a, 20b. Here, the refrigerant gas releases heat by condensing and exerts a heating effect, and then returns to the outdoor unit 1 through the indoor expansion devices 21a and 21b and the liquid pipe 6.

On the other hand, the outdoor unit 1 starts operation upon receiving an operation start signal from one or both of the indoor units 2a and 2b, but the discharge pressure and suction detected by the discharge pressure sensor 30 and the suction pressure sensor 31 The outdoor heat exchanger 9 is operated in condenser mode or evaporator mode depending on the pressure state.

When in the condenser mode, the solenoid valve 12 and check valve 13 are opened, and the solenoid valve 14 and check valve 15 are closed. Further, the outdoor diaphragm device 11 is fully opened. The refrigerant gas that has exited the compressor 7 passes through a solenoid valve 12 and a check valve 13 and is condensed in an outdoor heat exchanger 9, followed by an outdoor throttling device 11,
By flowing into the liquid pipe 6 through the accumulator 8, it is sent to the indoor units 2a and 2b. The refrigerant that has returned from the indoor units 2a, 2b through the suction pipe 5 is returned to the compressor 7 via the accumulator 8.

When in the evaporator mode, the solenoid valve 14 and check valve 15 are opened, and the solenoid valve 12 and check valve 13 are closed. Moreover, the outdoor diaphragm device 11 is set to a predetermined opening degree for the evaporator. Refrigerant gas leaving the compressor 7 is supplied to the indoor units 2a, 2b through the discharge pipe 4. The refrigerant that has returned from the indoor units 2a, 2b through the liquid pipe 6 passes through the accumulator 8, is throttled and expanded by the outdoor expansion device 11, is evaporated in the outdoor heat exchanger 10, and is then passed through the solenoid valve 14 and check valve 15. It is added to the accumulator 8 through. The refrigerant separated into vapor phase here is returned to the compressor 7.

The outdoor unit 1 basically operates as described above, and the outdoor unit controller 40 adjusts the capacity of the compressor 7 according to the discharge pressure and suction pressure of the compressor 7, which change depending on the operating conditions of the indoor units 2a and 2b. control,
Controls the fan speed of the outdoor fan 10, selects the mode of the outdoor heat exchanger 9, etc. Next, the control operation of the outdoor unit controller 40 will be explained with reference to the flowchart of FIG. 4.

Power is turned on to the outdoor unit 1 and the outdoor unit controller 40 starts. First, in step ST1, it is checked by checking the input state of the digital input section 45 in FIG. 3 whether a start/stop signal indicating the start or stop (hereinafter referred to as "start/stop") of the indoor units 2a, 2b has been input. . Next, in step ST2, it is checked whether all the indoor units 2a, 2b have stopped. In the case of a complete stop, there is no need to operate the outdoor unit 1, so the process proceeds to step ST3, where the compressor capacity control section 47 sets the capacity Qcomp of the compressor 1 to 0%, and
The fan speed AKe is controlled by the fan speed control section 46.
is set to 0% and a stop signal for the compressor 1 is outputted from the digital output section 48, after which the process returns to step ST1.

[0017] In step ST2, the indoor units 2a and 2b
If the indoor unit 2a and/or 2b, hereinafter referred to as the indoor unit 2, is not fully stopped, the process proceeds to step ST4.
) is the first operation. If it is the first operation, proceed to step ST5, set Qcomp to m%,
AKe is set to a predetermined value of n% and the compressor 7 is started. This is because unless the compressor 7 is started, the increase in the discharge pressure Pd and the decrease in the suction pressure Ps will not begin, and Pd and Ps cannot be changed, so the above settings are made. Here, the values of m and n are set as small as possible so that Pd and Ps do not become abnormal pressures. Next, in step ST6, the timer is set to t1.
After setting the time, the process returns to step ST1. Also,
If it is not the first operation in step ST4, Pd, P
Since s is already a certain pressure value during operation, step ST5 is bypassed and a timer is set in step ST6.

The above timer time t1 is the indoor unit 2.
After the start/stop of the compressor and the control by the compressor control unit 47 and fan speed control unit 46 are performed, the results are shown as Pd.
, Ps, and the next process is suspended while t1 time elapses from step ST6 to step ST7.

When time t1 has elapsed in step ST7, Pd and P are input from the analog input section 44 in step ST8.
Enter s. Next, in steps ST9 and ST10, P
d, Ps within a predetermined range (PdL<Pd<PdH,P
SL<PS<PSH), and if both are within the predetermined range, compressor capacity control and fan speed control are not required. In other words, outdoor unit 1 is in good operating condition. Assuming that there is, step S
Return to T6. In addition, in the case of air conditioners that use R-22 as the refrigerant, normally

[0020]

[Math 1]

[0021]

[Math 2]

[0022] If it exceeds this range, it is deemed that control is necessary, and the process proceeds to step ST11.

[0023] Here, a combination of Qcomp and AKe is selected from (Table 1) and the current compressor capacity and fan speed. That is, the current compressor capacity is Qi, the fan speed is AKj, and the one step above each is Qi+1, AKj+
1, one step below is Qi-1, AKj-1, then
A maximum of nine combinations of (Qcopm, AK) are possible as shown in (Table 2).

[0024]

[Table 1]

[0025]

[Table 2]

First, in step ST11, the maximum nine combinations described above are selected. Next, in step ST12, the amount of change Δ from the current value for Qcopm, AKe is
Qcopm, ΔAKe

[0027]

[Math 3]

[0028]

[Math 4]

Next, in step ST13, each of the above-mentioned changes ΔQ
For copm and ΔAKe, pressure changes are calculated using the following equations. Here, a, b, c, and d are gains.

[0030]

[Math 5]

[0031]

[Math 6]

Furthermore, the predicted value Pd of the pressure after these controls
*, Ps* are calculated. Next step ST14
Then, the deviation from the high pressure setting target value Pd θ and the low pressure setting target value Ps θ is calculated from Pd * and Ps *.

[0033]

[Math 7]

[0034]

[Math. 8]

[0035]

[Math. 9]

[0036] Here, η: Coefficient 0≦η≦1

003
7] ζ: Coefficient 0≦ζ≦1

The priority of the high pressure side and the low pressure side is shown as η+ζ=1. Then, the combination of ΔQcomp and ΔAKe that minimizes the value of A (minimizes the deviation) is determined and selected as the control amount.

From the above, after calculating ΔQcomp, ΔAKe, in step ST15, the current value Qcomp, A
Qcomp is outputted from the inverter 39 via the compressor capacity control section 47 in FIG. 3, and AKe is outputted from the inverter 38 via the fan speed control section 46. Then step S
Return to T6 and repeat these cycles thereafter.

[0040]

[Problems to be Solved by the Invention] Since the conventional multi-type air conditioner is configured as described above, when the operation mode of the indoor units 2a and 2b is only the heating mode, the suction of the compressor 7 is Even if the pressure and discharge pressure are within the set range, the capacity of the outdoor heat exchanger 9 may be smaller than the capacity of the compressor 7, and even if the predetermined heating capacity of the indoor units 2a and 2b is obtained, the compressor There was a problem that the heating capacity was not fully demonstrated for the capacity of 7.

[0041] This invention was made to solve the above-mentioned problems, and it is possible to operate the compressor with suction pressure and discharge pressure within set values when the indoor unit is only in the heating mode. , and maximize the capacity of the outdoor heat exchanger to maximize the heating capacity for the compressor capacity.
It is also an object of the present invention to provide a multi-air conditioner that can obtain a predetermined heating capacity of an indoor unit.

[0042]

[Means for Solving the Problems] The multi-type air conditioner according to the present invention distinguishes between cases in which the indoor unit operates solely for cooling, or cases in which cooling and heating are operated simultaneously, and cases in which it operates only for heating. In the case of , the control method is the same as the conventional control method, and in the latter case, the suction pressure and discharge pressure of the compressor are within the set range from the combination of the control amount of the compressor capacity and fan speed, and The compressor capacity and fan speed are controlled so that the capacity of the outdoor heat exchanger reaches the maximum required capacity.

[0043]

[Function] In the multi-type air conditioner according to the present invention, when the suction pressure and discharge pressure of the compressor are within the set range, and when all indoor units are in heating operation, the outdoor heat exchanger capacity is adjusted to the maximum required capacity. Since the compressor capacity and fan speed are controlled so that the compressor capacity is maintained, the heating capacity for the compressor capacity is fully demonstrated, and a predetermined heating capacity of the indoor unit can be obtained.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a control flowchart of the present invention. The control flow from steps ST1 to ST15 is the same as the conventional one. The control flow of steps ST16 to ST18 is the control content in this invention. Note that the configuration of the multi-type air conditioner is the same as that in FIG. 2, so the explanation will be omitted.

Next, the operation will be explained.

[0047] The operations of the refrigerant system and outdoor unit controller are the same as before. Further, in the control flowchart of FIG. 1, the flow from steps ST1 to ST13 is the same as the conventional flow, so the explanation will be omitted.

Now, the control according to the present invention determines the compressor capacity and fan speed to be operated by determining the compressor capacity control amount and the fan speed control amount by the calculations in steps ST16 to ST18 in FIG.

In FIG. 1, up to nine pressure deviations A can be obtained through the calculations up to step ST13. Next, in step ST16, it is determined whether only heating is being operated. If only heating is being operated, the process proceeds to step ST17; otherwise, the process is proceeding to step ST14. In step ST17, these pressure deviations A are compared, and n patterns (1≦n<9) are selected in descending order of value, and patterns 9-n are excluded from the selection. For example, if n=3, the resulting combinations are as follows.

[0050]

[Math. 10]

Next, in step ST18, AKj-1 and AKj are compared among the above combinations, the larger value is selected, and one combination containing the larger value is determined. That is, if AKj-1 <AKj, then

[0052]

[Math. 11] becomes.

[0053] Furthermore, if the values of ΔAKe are equal,
One combination with the minimum pressure deviation A is selected from the above n combinations, and control is performed based on this combination.

[0054]

As described above, according to the present invention, when the indoor unit only performs heating operation, in the process of determining the control amount of the compressor capacity and fan speed of the outdoor unit, the capacity of the outdoor heat exchanger is In order to maximize the use of Qcomp and AKe, a combination of Qcomp and AKe that increases AKe is selected, so that the heating capacity for the compressor capacity can be fully demonstrated and the specified indoor unit heating capacity can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is a control flowchart of a multi-type air conditioner according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional multi-type air conditioner.

FIG. 3 is a block diagram of an outdoor unit controller of the device.

FIG. 4 is a control flowchart of the device.

[Explanation of symbols]

1 Indoor units 2a, 2b Outdoor unit 4 Refrigerant discharge piping 5 Refrigerant suction piping 6 Refrigerant liquid piping 7 Compressor 9 Outdoor heat exchanger 10 Outdoor fan 30 Discharge pressure sensor 31 Suction pressure sensor 40 Outdoor unit controller Note that the same symbols in the figure Indicates the same or equivalent part. Patent applicant Mitsubishi Electric Corporation Agent
Patent attorney Hiroshi Tazawa (2 others)

Claims (1)

[Claims] Claim 1: An outdoor unit having a capacity-controllable compressor, a variable-speed outdoor fan evaporator, and an outdoor heat exchanger that can be switched to a condenser is connected to a plurality of indoor units by refrigerant piping, and each In a multi-type air conditioner that allows cooling and heating to be selected arbitrarily for each indoor unit, the compressor capacity and fan speed are divided by dividing the compressor capacity into M predetermined stages and the fan speed into N predetermined stages. a control means for performing stepwise control of the compressor, a detection means for detecting compressor suction pressure and compressor discharge pressure as control inputs, and a deviation between the detected suction pressure and the target value of the suction pressure, the discharge pressure and the Calculate each deviation from the target value of pressure, and calculate these two
a calculation means for selecting a compressor capacity and a fan speed that minimize an evaluation value consisting of two deviations, and providing the selected compressor capacity and fan speed to the control means.