JPH03117844A - Method of controlling air conditioner - Google Patents

Abstract

PURPOSE:To exhibit maximum heating capacity when required even when an air conditioner is changed over to a rated capacity variable operation by fixing the air conditioner to a maximum capacity variable operation after entering a defrosting operation. CONSTITUTION:Maximum frequency limiting means 26 are provided in the output path of target frequency calculating means 23. On the basis of the outputs of operation/stop mode discriminating means 21, timer means 22, defrosting control means 24 and humidity discriminating means 25, a compressor operating frequency is limited to perform a rated capacity variable operation and even a maximum target operation frequency corresponding to an air conditioning load is outputted as it is, performing a maximum capacity variable operation. Inverter output frequency control means 27 is connected to the maximum frequency limiting means 26 to control an inverter apparatus 28 for driving a compressor 1. Since an air conditioner is fixed to the maximum capacity variable operation after entering a defrosting operation, maximum heating capacity can be exhibited in accordance with the air conditioning load in a condition requiring a defrosting operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a control method for a variable capacity air conditioner.

(Prior Art) As an example of this type of air conditioner, there is a so-called inverter air conditioner that changes the operating frequency of a compressor for refrigerant circulation depending on the deviation between a set value and a detected value of room temperature. This allows the capacity to be controlled in stages from the minimum to the maximum according to the air conditioning load, but if this maximum or minimum capacity is set as a model specification, various inconveniences will occur. Therefore, the Japan Industrial Standards stipulate that the capacity determined by 4pj under specific temperature conditions be displayed as the rated capacity.

Due to the necessity of measuring the rated capacity, in normal operation, the maximum capacity variable operation is first carried out to follow the air conditioning load and control the capacity from the minimum to the maximum, and when the indoor temperature exceeds a predetermined value,
Alternatively, when a predetermined time has passed since the start of operation and the room temperature has exceeded a predetermined value, the operation is switched to variable rated capacity operation in which the capacity is controlled from the minimum to the rated according to the air conditioning load.

(Problems to be Solved by the Invention) In the conventional air conditioner control method described above, switching from maximum capacity variable operation to rated capacity variable operation focuses on indoor temperature and operating time.

For this reason, even if it is necessary to operate at the maximum capacity, such as when the outside temperature drops after switching to the rated capacity operation, there is a problem that the operation can only be performed at a smaller rated capacity.

This invention was made in order to solve the above-mentioned problems, and aims to provide a control method for an air conditioner that can demonstrate the maximum heating capacity when necessary even if the operation is switched to variable rated capacity operation. 1j target.

[Purpose of the invention]

(Means for Solving the Problems) This invention provides variable maximum capacity operation in which the capacity is controlled from the minimum to maximum according to the air conditioning load, and variable rated capacity operation in which the capacity is controlled from the minimum to the rated according to the air conditioning load. The switchable air conditioner may be characterized in that the maximum capacity variable operation is fixed after the defrosting operation is started.

Further, instead of using the defrosting operation as a condition, the variable maximum capacity operation is performed during a period when the outside temperature is below a predetermined value.

(Function) In this invention, after starting defrosting operation, the maximum capacity is fixed at 11 variable operation, so in situations where defrosting operation is required, the maximum heating capacity is exerted according to the air conditioning load. be able to.

Furthermore, depending on the climate conditions, even if the outside temperature drops by a certain degree, dew may not condense enough to require defrosting operation.

In such a situation, by performing variable maximum capacity operation on the condition that the outside temperature has fallen below a predetermined value, the maximum heating capacity can be demonstrated according to the load during the empty week.

(Example) FIG. 1 is a block diagram showing a schematic configuration of an apparatus implementing the present invention together with a refrigeration cycle.

Here, considering the case of heating operation, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 and is co-supplied to the indoor heat exchanger 4 having the indoor fan 3, where it is condensed. After that, its temperature and flow rate are adjusted by an expansion valve 5, and then it is vaporized by an outdoor heat exchanger 7 having an outdoor fan 6.
It passes through the four-way valve 2 again and returns to the compressor 1. Note that when the cooling operation is performed, the functions of the indoor heat exchanger 4 and the outdoor heat exchanger 7 are reversed, but since this is not directly related to the present invention, a description thereof will be omitted.

In this refrigeration cycle system, a temperature sensor 11 is attached to the outdoor heat exchanger 7 to detect its own temperature, and a room temperature sensor 12 is provided near the indoor heat exchanger 4. Of these, the temperature sensor 11 is connected to a defrost control means 24 that determines whether defrosting is necessary and outputs a defrost command, and also generates a four-way valve ni control signal. It is also connected to the target frequency calculation means 23. This [1 standard frequency calculating means 23 also performs PID calculation on the deviation between the detected value of the room temperature and the set value,
The target operating frequency of the compressor corresponding to the load for one week of empty operation is calculated. On the other hand, the operation/stop switch 14 and the operation mode changeover switch 15 are connected to the operation/stop mode discrimination means 21, and the operation/stop mode discrimination means 21 indicates whether the operation is cooling operation or heating operation together with the operation signal (6 In addition, this run/stop 1 and mode discrimination means 21 includes a timer means 22.
is connected, and this timer means 22 sets the heating operation time to 31 o'clock and outputs a time-up signal after a predetermined time has elapsed. Further, a temperature determining means 25 is also connected to the room temperature sensor 12 for determining whether the room temperature exceeds a predetermined value based on the output thereof. Furthermore, maximum frequency limiting means 26 is provided in the output path of the target frequency calculating means 23,
Based on the outputs of the run/stop F mode discrimination stage 21, the timer means 22, the defrost control means 24, and the temperature discrimination means 25, the compressor operating frequency can be limited to perform variable rated capacity operation, or to reduce the load to 1 liter from empty. Even if the corresponding maximum target operating frequency is output as is, maximum capacity variable operation is performed.

An inverter output frequency control means 27 is connected to the maximum frequency limiting means 26, and the inverter output frequency control means 27 is configured to control an inverter device 28 that drives the compressor.

The operation of this embodiment configured as described above will be described below with reference to the flowchart of FIG. 2 showing the overall processing procedure.

First, if the run/stop switch 14 is switched to the running side, the run/stop mode discrimination means 21 discriminates this and outputs an operation start command (step 101); conversely, the run/stop switch 14 is turned off. If the switch is switched to the heating side, or if it has been switched to the heating side, it remains on standby (step 1 (12).Also, if the operation mode changeover switch is switched to the heating side, the operation/stop mode discriminating means 21 similarly determines this. On the other hand, if it is switched to the cooling side, a cooling mode signal is output (step 104). Note that a description of the operation in the cooling mode will be omitted.

Next, the timer means 22 that has received the operation start command starts timing from that point in time (Step 105), and upon receiving the operation start command and the heating mode signal, the timer means 22 calculates the temperature of the room temperature sensor 12 at that time Detected temperature (T
) and the deviation of the set temperature (T 2 ) of the temperature setting device 13, the target operating frequency (f) of the compressor 1 is determined, and this is output as an operating frequency command (step 106).

Next, the maximum frequency limiting means 26 receives this frequency command, determines whether the time set in the timer means 22 has elapsed, and outputs the output from the target frequency calculating means 23 until this time has elapsed. The obtained operating frequency command is given to the inverter output frequency side IF stage 27 (step 107). The inverter output frequency control means 27 controls the inverter device 28 according to this operating frequency command (
Step 112).

As a result, the compressor 1 is operated with variable maximum capacity in accordance with the air conditioning load from the start of operation until the time set in the timer means 22 has elapsed.

Next, when the set time of the timer means 22 has elapsed and the time-up signal is output, the maximum frequency limiting means 26 determines whether the detected temperature (T) exceeds 19°C based on the output of the temperature determining means 25. If the temperature is not higher than 19° C., the target operating frequency outputted from the target frequency calculation means 23 is still given to the inverter output frequency control means 27.

On the other hand, the defrosting control means 24 outputs a four-way valve control signal to perform defrosting operation when defrosting is necessary, based on the outdoor heat exchanger temperature (T 2 ) detected by the temperature sensor 1. Only when the room temperature exceeds 19° C., the target frequency calculation means 23 determines whether or not the defrosting operation has been performed since the start of operation (Step 109); if the defrosting operation has not been performed,
The target operating frequency (f) at that time is the rated frequency (fln
axl) is exceeded (step 11
(1).

Here, the 11th station operating frequency (f) is the rated frequency (f
), the maximum frequency term max.

As a result, the operating time was over 14 minutes and the room temperature was 19
When the temperature exceeds .degree. C., the compressor 1 is operated at variable rated capacity.

−Jj, if the defrosting operation has been performed at least once since the start of operation, the target operating frequency (f) described above
However, without determining whether or not it exceeds the rated frequency (fIllax□), the drift frequency calculation stage 1 23 is carried out as is.
A frequency command according to the target operating frequency (f) is output to the inverter output frequency control stage 27.

As a result, after the defrosting operation, the maximum capacity variable operation is fixed.

In the above example, when the defrosting operation was actually performed, the maximum capacity variable operation was identified after that, but depending on the autumn conditions, the defrosting operation may not shift even if the outside temperature drops. There is. In this situation, detect the outside temperature and
The maximum capacity variable operation may be performed during a period when the temperature is, for example, 0° C. or lower.

A specific configuration to deal with this is to further provide a temperature sensor that detects the outside temperature, and when the detected value falls below a certain value, instead of setting the upper limit to the rated operating frequency (a + axl), the maximum operating frequency is The upper limit may be set to the frequency (f).

aX [Effect of the Invention] As is clear from the above explanation, according to the present invention, after the defrosting operation is started, the maximum capacity nJ variable operation is fixed, so under the situation where the defrosting operation is required, Under conditions that require maximum heating capacity, the maximum heating capacity can be demonstrated according to the air conditioning load.

Furthermore, depending on climate conditions, even if the outside temperature drops, dew may not condense enough to require defrosting operation.

In such situations, maximum capacity variable operation is performed on condition that the outside temperature falls below a predetermined value, and in situations that require maximum heating capacity, the maximum heating capacity is demonstrated according to the air conditioning load. be able to.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an apparatus implementing the present invention together with a refrigeration cycle system, and FIG. 2 is a flowchart for explaining the operation of the apparatus. DESCRIPTION OF SYMBOLS 1... Compressor, 2... Four-way valve, 4... Indoor heat exchanger, 7... Outdoor heat exchanger, 11... Temperature sensor, 12
...Room temperature sensor, 13...Temperature setting device, 21...
Run/stop 1-mode discrimination means, 22... timer means, 24... defrost control 11 steps, 25... temperature discrimination -1
Stage, 26... Maximum frequency limiting means, 27... Inverter output frequency control means, 28... Inverter device.

Claims (1)

[Scope of Claims] 1. An air conditioner that can be switched between maximum capacity variable operation where capacity is controlled from minimum to maximum according to air conditioning load and rated capacity variable operation where capacity is controlled from minimum to rated according to air conditioning load. A control method for an air conditioner, characterized in that the maximum capacity variable operation is fixed after the defrosting operation starts. 2. In an air conditioner that can be switched between maximum capacity variable operation where capacity is controlled from minimum to maximum according to air conditioning load and rated capacity variable operation where capacity is controlled from minimum to rated according to air conditioning load, when the outside temperature is set A method for controlling an air conditioner, characterized in that the variable maximum capacity operation is performed during a period when the maximum capacity is below a value.