JPH04363536A - Operation control method for air-conditioner - Google Patents

Abstract

PURPOSE:To enable control of heating and defrosting to an optimum state according to an operation state when defrosting operation is effected during heating operation. CONSTITUTION:A capacity variable type compressor 1, a four-way valve 2, an outdoor heat-exchanger 3, a throttle mechanism 4, and an indoor heat- exchanger 5 are interconnected, in the order named, to form a freeze cycle. In the freezing cycle, in a method to control running of an air-conditioner provided with a hot gas bypass circuit 8 to effect defrosting through the flow of high temperature refrigerant gas from the compressor 1 to the outdoor heat- exchanger 3 during heating operation, during the starting of defrosting operation, the operation state up to that time of the compressor 1 is decided. When the compressor 1 is run at maximum capacity, an indoor fan 7 is stopped, and when the compressor is run at low capacity, defrosting is carried out in a state that the indoor fan 7 is left running.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an air conditioner, and more particularly to a method of controlling the operation of an air conditioner when defrosting is performed during heating operation.

0002

[Prior Art] As shown in Fig. 3, an air conditioner has a variable capacity compressor 1 driven by an inverter, a four-way valve 2, an outdoor heat exchanger 3, a throttling mechanism 4, and an indoor heat exchanger 5 connected in sequence. A refrigeration cycle is constructed. Further, the outdoor heat exchanger 3 is provided with an outdoor fan 6, and the indoor heat exchanger 5 is provided with an indoor fan 7. During cooling, the high-temperature, high-pressure refrigerant from the compressor 1 is passed through the outdoor heat exchanger 3, reduced in pressure by the throttling mechanism 4, and evaporated in the indoor heat exchanger 5 to cool the room.
During heating, the four-way valve 2 is switched to flow high-temperature, high-pressure refrigerant into the indoor heat exchanger 5 in the opposite direction to that during cooling, where it is condensed to heat the room, and after being depressurized by the throttling mechanism 4, it is transferred to the outdoor heat exchanger. 3 to evaporate it and return it to the compressor 1.

In recent years, defrosting during heating has been accomplished by connecting the discharge side of the compressor 1 and the inlet side of the outdoor heat exchanger 3 during heating with a hot gas bypass circuit 8 instead of switching to the cooling cycle. A two-way valve 9 connected to 8 is opened, and high-pressure refrigerant gas is introduced into the outdoor heat exchanger 3 to perform defrosting.

This defrosting method using hot gas bypass has the advantage that operation can be performed while heating continues, compared to defrosting by switching cycles and stopping heating operation.

[0005]

[Problems to be Solved by the Invention] However, in this defrosting method, the heat in the refrigeration cycle is released into the room via the indoor heat exchanger 5 even during defrosting, so it is sent to the outdoor heat exchanger. There is a problem that the amount of high-temperature refrigerant decreases and the defrosting time becomes longer.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and provide an air conditioner operation control method that can optimally control heating and defrosting depending on the operating conditions when defrosting operation is performed during heating operation. There is a particular thing.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a refrigeration cycle by sequentially connecting a variable capacity compressor, a four-way valve, an outdoor heat exchanger, a throttling mechanism, and an indoor heat exchanger. In the operation control method of an air conditioner, the refrigeration cycle is equipped with a hot gas bypass circuit that defrosts the high-temperature refrigerant gas from the compressor by flowing it to the outdoor heat exchanger during heating operation. When starting, the operating status of the compressor up to that point is judged, and if the compressor was operating at high capacity, the indoor fan is stopped, and when the compressor is operating at low capacity, defrosting is performed while the indoor fan is running. It was designed to do so.

[0008]

[Operation] According to the above configuration, when defrosting is performed during heating operation, when the compressor, etc. is operating at or near maximum capacity, the indoor fan is stopped and defrosting is performed. By doing so, defrosting can be completed in a short time, and when the compressor is operating at low capacity, the indoor fan can be operated to defrost while heating continues, thereby achieving optimal defrosting and heating.

[0009]

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

First, the refrigeration cycle of the air conditioner of the present invention is as shown in FIG. To explain this FIG. 3 in more detail, the compressor 1 is operated with variable capacity by an inverter device (
For example, during heating, the operating frequency is 30 to 150 Hz, and during cooling, the operating frequency is 30 to 100 Hz. The operating frequency of the compressor 1 is determined based on the difference between the set temperature and the indoor temperature, that is, depending on the air conditioning load. The remote control that operates this air conditioner also includes heating, cooling,
It has a setting switch that allows you to set normal operating conditions such as temperature setting and air volume setting, as well as maximum capacity operation (the compressor operates at the maximum operating frequency, and the set temperature is within the setting range (18 to
A request switch is provided for the maximum value (30℃), the maximum air volume for indoor fans, etc. Although not shown in the figure, the outdoor heat exchanger 3 has a heat exchanger temperature Tk during heating operation.
A temperature sensor is provided for both frost detection and defrosting completion.

In the air conditioner shown in FIG. 3, the heat exchanger temperature Tk of the outdoor heat exchanger 3 is constantly detected by a temperature sensor for detecting frost formation and for finishing defrosting during heating operation, and the heat exchanger temperature Tk When it detects the defrosting start temperature TES, it determines that defrosting is necessary and opens the two-way valve 9 to direct the high-temperature refrigerant gas from the compressor 1 to the outdoor heat exchanger 3 via the hot gas bypass circuit 8.
to perform defrosting operation. During this defrosting operation, when the heat exchanger temperature Tk detects the defrosting end temperature TFS, it is assumed that the defrosting has been completed and the two-way valve 9 is controlled to be closed.

Now, in the present invention, when defrosting operation is performed using this hot gas bypass, it is necessary to keep the indoor fan 7 in the ON state depending on the operating status of the heating operation up to that point.
The selection is made by determining whether or not to use FF. Specifically, when the air conditioning load is large and the compressor is operating near the maximum capacity, or when the user selects the maximum capacity operation request switch on the remote controller mentioned above and requests maximum capacity operation, etc. In this case, the indoor fan 7 is turned OFF and its operation is stopped so that the defrosting operation is completed quickly.Also, when the air conditioning load is small and the operating frequency of the compressor is low, the defrosting operation is performed while the indoor fan continues to operate. It was designed to do this.

FIG. 1 shows the operation control of the air conditioner according to the present invention.
This will be explained using a flowchart.

First, heating operation is started, and the heat exchanger temperature T
It is determined whether Tk has reached the defrosting start temperature TES (step 1), and if the heat exchanger temperature Tk has not reached the defrosting start temperature TES (NO), heating operation control is performed as is, and the heat exchanger When the temperature Tk reaches the defrosting start temperature TES (YES), it is then determined whether the request switch for maximum capacity operation is turned on (Step 2), and whether or not the set temperature is 29°C or less (Step 3). , determine whether the air volume setting is strong wind (step 4), determine whether the operating frequency f≧100 Hz (step 5), and determine whether the operating frequency was 100 Hz or more during 70% or more of the operation (step 6), and make judgments for each of these steps. If YES, turn on the two-way valve, turn off the indoor fan, and perform defrosting operation. In the case of defrosting operation when the air conditioning load is large, the defrosting start temperature TES is set to TES = TES + 1 (°C) so that defrosting can be performed early during the next defrosting operation, and then the heat exchange It is determined whether the chamber temperature Tk has reached the defrosting end temperature TFS (step 7), and when the defrosting is completed, the two-way valve is turned OFF and the process returns to the initial heating control.

[0015] Also, if the judgments in steps 1 to 5 are NO and the judgment in step 6 is NO, the air conditioning load is low, so the two-way valve is turned on.
The defrosting operation is performed with the temperature set to N, and the indoor fan continues to operate in the ON state, and then in step 7 it is determined whether the defrosting has ended.

FIG. 2 shows the change over time in the operating frequency of the compressor from the start of heating operation, and the solid line in the figure shows curve a.
is the change over time in the operating frequency of the compressor when the air conditioning load is large, and the curve b shown by the dotted line shows the change over time in the operating frequency of the compressor when the air conditioning load is small. When it is determined that defrosting is necessary under the circumstances indicated by the arrows in the figure, the indoor fan is stopped in curve a, and the indoor fan continues to operate in curve b.

[0017] In the above, during normal heating operation in an air conditioner, during start-up operation or during severe cold season,
In conventional defrosting, there are operating situations that require conscious air conditioning that blows high-temperature air with high capacity, and operating situations that require unconscious air conditioning with low capacity and low noise when the room temperature reaches the set temperature. , the system was aimed at unconscious air conditioning. For this reason, when the load approaches the set temperature and requires low-capacity operation, the indoor fan is operated even during defrosting, achieving unconscious defrosting that does not significantly reduce the room temperature. Sometimes, defrosting takes a long time, and the heating capacity is also low, causing the room temperature to continue to drop for a long time. In the present invention, such operating conditions are accurately judged, and if high capacity is required, the indoor fan is stopped during defrosting to quickly complete defrosting, and once the defrost is completed, the air conditioning is turned on at high capacity. By performing both heating operation and defrosting operation when the capacity is low, it is possible to perform defrosting operation that is adapted to the load and operating conditions, and heating can be performed with less unpleasant periods.

[0018] Also, since the amount of frost formation is large during high-capacity operation, the detection temperature of the defrost start sensor that detects frost formation should be switched to a higher setting to detect frost formation earlier than usual. You can finish defrosting even more quickly.

[0019]

[Effects of the Invention] In summary, according to the present invention, when defrosting is performed during heating operation, the indoor fan is stopped when the compressor, etc. is operating at or near maximum capacity. By defrosting, defrosting can be completed in a short time, and when the compressor is operating at low capacity, the indoor fan can be operated to continue heating while defrosting, resulting in optimal defrosting and heating. can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a flowchart illustrating an embodiment of the present invention.

FIG. 2 is a diagram showing changes over time in the operating frequency of the compressor according to operating conditions in the present invention.

FIG. 3 is a diagram showing a refrigeration cycle of an air conditioner according to the present invention and a conventional example.

[Explanation of symbols]

1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Aperture mechanism 5 Indoor heat exchanger 8 Hot gas bypass circuit 9 Two-way valve

Claims (1)

[Claims] Claim 1: A variable-capacity compressor, a four-way valve, an outdoor heat exchanger, a throttling mechanism, and an indoor heat exchanger are connected in sequence to form a refrigeration cycle, and the refrigeration cycle is connected to the compressor during heating operation. In an operation control method for an air conditioner equipped with a hot gas bypass circuit that defrosts defrost by flowing high-temperature refrigerant gas through an outdoor heat exchanger, when starting defrost operation, the previous operating status of the compressor is determined. An air conditioner operation control method characterized in that an indoor fan is stopped when the compressor is operating at high capacity, and defrosting is performed with the indoor fan operating when the compressor is operating at low capacity.