JPH07218004A - Motor operated expansion valve controller for air conditioner - Google Patents

Abstract

PURPOSE:To provide a motor operated expansion valve controller for an air conditioner in which a cooling capacity can be simultaneously obtained by controlling degree of superheat of suction refrigerant gas of a compressor at the time of cooling with a high humidity and preventing diffusion of water droplet from an indoor unit due to condensation of an indoor fan. CONSTITUTION:An indoor heat exchanger liquid side sensor, an indoor heat exchanger gas side sensor 2 are provided in an indoor heat exchanger 107, this temperature difference is detected by a minimum opening controller 3, and a minimum opening of a motor operated expansion valve 105 is limited by the controller 3 while controlling degree of superheat by a temperature difference of a suction temperature sensor 117 and a saturated temperature sensor 116 at the time of cooling in the case that the difference falls within a predetermined value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric expansion valve control device in a refrigeration cycle of an air conditioner.

[0002]

2. Description of the Related Art In recent years, the separation type air conditioner has a tendency that the amount of refrigerant circulation greatly changes due to the use of an inverter or the like. Therefore, a fine refrigerant flow rate control is required for the efficiency and safety of products.

Conventionally, the structure of the electric expansion valve control device of this type of separation type air conditioner has generally been as shown in FIG. The configuration will be described below with reference to FIG.

As shown in the figure, an outdoor unit 101 is provided with a compressor 102 controlled by an inverter, a four-way valve 103 for switching a refrigerant flow path, an outdoor heat exchanger 104, and an electric expansion valve 105 of a refrigerant throttling mechanism. There is.

In the above structure, the compressor 102 is driven by an operation command from the indoor unit 106, and the compressor 10
The refrigerant discharged from 2 passes through the four-way valve 103, the outdoor heat exchanger 104 during cooling, and the indoor unit 1 during heating.
It is condensed in the indoor heat exchanger 107 in 06, and is decompressed by the electric expansion valve 105, and at the time of cooling, the indoor heat exchanger 107,
During heating, heat is exchanged as evaporating action in the outdoor heat exchanger 104 to return to the compressor 102, forming a refrigeration cycle.

Further, the operation command from the indoor unit 106 is transmitted to the inverter unit 109 and the superheat control device 110 through the signal line 108, and the inverter unit 109 uses the signal from the indoor unit 106 and the outside air temperature sensor 111 to drive the compressor 102. The superheat degree control device 110 determines the drive frequency of the bypass pipe 115 connected to the suction pipe 114 led to the compressor 102 from the liquid receiver 112 via the saturation temperature capillary tube 113 at regular intervals. The temperature difference between the saturation temperature sensor 116 attached to the suction pipe 114 and the suction temperature sensor 117 attached to the suction pipe 114 is detected, and the superheat of the entire refrigeration cycle is detected based on the temperature difference. Valve 10
The command of opening and closing was transmitted to 5 and it adjusted to the proper superheat degree.

[0007]

In such a conventional electric expansion valve control device for an air conditioner, the electric expansion valve 105 is opened to obtain a superheat during cooling operation when the indoor humidity is high. Although the degree of superheat is increased by limiting the temperature, the temperature of the indoor heat exchanger 107 is biased at that time, so that a partial deviation occurs in the dehumidification of the indoor air passing through the indoor heat exchanger 107, and the indoor heat exchange is also performed. Since the indoor fan 4 is cooled by the device 107, the high-humidity air comes into contact with the indoor fan to cause dew condensation on the indoor fan 4, and as a result, water droplets from the indoor unit are generated as the indoor fan rotates. There was a problem of blowing out. Further, when various sensors detect the case where the indoor fan is in a condition where dew condensation is likely to occur, the frequency of the compressor 102 is lowered by the inverter, so that the cooling capacity of the indoor unit 106 must be sacrificed. .

The present invention is intended to solve the above-mentioned problems, and it is possible to control the degree of superheat even during cooling operation with high humidity.
It is a first object of the present invention to provide an electric expansion valve control device for an air conditioner, which can prevent dew condensation of an indoor fan and maintain cooling capacity.

A second object is to prevent dew condensation on the indoor fan under the condition that the humidity near the indoor unit is high and the followability of the electric expansion valve opening control is poor at the time of starting the compressor and the transient period of the operation.

[0010]

In order to achieve the first object, an electric expansion valve control device for an air conditioner according to the present invention comprises:
A first means is a compressor controlled by an inverter in an outdoor unit, a four-way valve, an outdoor heat exchanger, an electric expansion valve, a refrigeration cycle in which a liquid receiver is provided, and between the liquid receiver and a suction pipe. An indoor heat exchanger is provided in an indoor heat exchanger provided in an indoor unit, which is provided with a bypass pipe having a saturation temperature capillary tube provided therein, and a suction temperature sensor and a saturation temperature sensor provided respectively in the suction pipe and the bypass pipe. Equipped with liquid side sensor and indoor heat exchanger gas side sensor,
A superheat control device for detecting a superheat by the temperature difference between the suction temperature and the saturation temperature, when the temperature difference between the indoor heat exchanger liquid side sensor and the indoor heat exchanger gas side sensor is large,
The configuration is provided with a minimum opening control device that limits the minimum opening of the electric expansion valve.

Further, in order to achieve the second object, the second means is to provide a humidity sensor in the indoor unit and detect the degree of superheat by the temperature difference between the suction temperature and the saturation temperature, and When the humidity measured by the humidity sensor is high, the minimum opening of the electric expansion valve is limited.

[0012]

With the configuration of the above-described first means, the present invention can control the degree of superheat in the cooling operation with high humidity and prevent the dew condensation of the indoor fan of the indoor unit and the reduction of the cooling capacity.

Further, by the constitution of the second means, it is possible to prevent the dew condensation of the indoor fan of the indoor unit by controlling the superheat degree even during the cooling operation with high humidity and during the transient period such as the start of the compressor. .

[0014]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the indoor side heat exchanger 107 in the indoor unit 106 is provided with an indoor heat exchanger liquid side sensor 1 and an indoor heat exchanger gas side sensor 2 respectively on the liquid side and the gas side, and the outdoor unit 101 is installed. Suction temperature sensor 1
17 and a saturation temperature sensor 116, the minimum opening control device 3 for controlling the minimum opening of the electric expansion valve 105 by the temperature difference between the indoor heat exchanger liquid side sensor 1 and the indoor heat exchanger gas side sensor 2. The configuration is provided.

With the above-described structure, when the indoor humidity is high, the value of the temperature difference between the suction temperature sensor 117 and the saturation temperature sensor 116 is transmitted to the superheat control device 110, and the superheat control is performed to ensure the cooling capacity. In order to do so, the superheat degree of the refrigerant sucked into the compressor 102 in the outdoor unit 101 must be set to a constant value, and therefore the temperature difference between the liquid side and the gas side of the indoor heat exchanger 107 tends to become large. The minimum opening control device 3 detects the temperature by the indoor heat exchanger liquid-side sensor 1 and the indoor heat exchanger gas-side sensor 2 in the indoor unit 106, and compares the temperatures so that the temperature difference is within a certain value. By controlling the minimum opening degree of the valve 105, efficient cooling operation is performed over the entire surface of the indoor heat exchanger 107. Therefore, the air flowing into the indoor fan is controlled by the indoor heat exchanger 107. Is dehumidified to one, so that the indoor fan will not be condensation, it can be prevented from the indoor unit 106 of blowing water droplets. Further, since the frequency of the compressor 102 is not lowered, it is possible to prevent the cooling capacity of the indoor unit 106 from being lowered.

As described above, according to the electric expansion valve control device for the air conditioner of the first embodiment of the present invention, superheat control is performed,
Even when the indoor humidity is high, it is possible to prevent dew condensation on the indoor fan and ensure the cooling capacity of the indoor unit 106.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

As shown in the figure, the humidity sensor 4 is provided in the indoor unit 106, the superheat control is performed by the detection of the suction temperature sensor 117 and the saturation temperature sensor 116 in the outdoor unit 101, and the temperature of the humidity sensor 4 is controlled. The minimum opening control device 3 for controlling the minimum opening of the electric expansion valve 105 is provided.

In the above structure, when the humidity in the room is high, the minimum opening control device 3 detects the humidity by the humidity sensor 4 and when the humidity becomes a certain value or more, the electric expansion valve 1
In order to control the minimum opening degree of 05, the air flowing into the indoor fan is uniformly dehumidified by the indoor heat exchanger 107, so that the indoor fan does not condense and water droplets are prevented from blowing out from the indoor unit 106. it can. Further, when the humidity is low, the superheat degree of the refrigerant sucked by the compressor 102 can be made large by controlling the superheat degree, and the frequency is not lowered, so that the cooling capacity of the indoor unit 106 can be prevented from being impaired.

As described above, according to the electric expansion valve control device for the air conditioner of the second embodiment of the present invention, the humidity in the room is high,
Prevents dew condensation on the indoor fan even during transient periods such as when the compressor starts, and when the humidity is low, superheat control is performed.
The cooling capacity of the indoor unit can be secured.

[0022]

As is apparent from the above embodiments, according to the present invention, the superheat control and the indoor heat exchanger liquid are controlled by the superheat control device for detecting the temperatures of the suction temperature sensor and the saturation temperature sensor of the compressor. By selecting the minimum opening control by the minimum opening control device that detects the temperature of the side sensor and the gas side sensor or the humidity by the humidity sensor, the indoor unit can be operated from the indoor unit even during cooling operation with high humidity while taking superheat. It is possible to provide an electric expansion valve control device for an air conditioner that can prevent the water droplets from being blown out and can maximize the cooling capacity of the indoor unit.

Further, even during the transitional period of the refrigerant behavior such as when the compressor is started by detecting the humidity by the humidity sensor, the minimum opening control is selected by the minimum opening control device to prevent water droplets from blowing out from the indoor unit. In addition, it is possible to provide an electric expansion valve control device for an air conditioner that can maximize the cooling capacity of the indoor unit.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of an electric expansion valve control device for an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a refrigeration cycle diagram of an electric expansion valve control device for an air conditioner of the second embodiment.

FIG. 3 is a refrigeration cycle diagram of a conventional electric expansion valve control device for an air conditioner.

[Explanation of symbols] 1 indoor heat exchanger liquid side sensor 2 indoor heat exchanger gas side sensor 3 minimum opening control device 4 humidity sensor 101 outdoor unit 102 compressor 103 four-way valve 104 outdoor heat exchanger 105 electric expansion valve 106 indoor Unit 107 Indoor heat exchanger 110 Superheat control device 112 Liquid receiver 113 Saturation temperature capillary tube 114 Suction pipe 115 Bypass pipe 116 Saturation temperature sensor 117 Suction temperature sensor

Claims (2)

[Claims] 1. A refrigeration cycle in which a compressor controlled by an inverter, an four-way valve, an outdoor heat exchanger, an electric expansion valve, and a liquid receiver are provided in an outdoor unit, and between the liquid receiver and a suction pipe. An indoor heat exchanger is provided in an indoor heat exchanger provided in an indoor unit, which is provided with a bypass pipe having a saturation temperature capillary tube provided therein, and a suction temperature sensor and a saturation temperature sensor provided respectively in the suction pipe and the bypass pipe. A superheat control device that includes a liquid side sensor and an indoor heat exchanger gas side sensor, and detects the superheat degree by the temperature difference between the suction temperature and the saturation temperature; the indoor heat exchanger liquid side sensor and the indoor heat exchanger gas side An electric expansion valve control device for an air conditioner, comprising a minimum opening control device that limits the minimum opening of the electric expansion valve when the temperature difference between the sensors is large. 2. A humidity sensor is provided in the indoor unit,
The air conditioner according to claim 1, wherein a superheat degree control device that detects a superheat degree based on a temperature difference between a suction temperature and a saturation temperature and a configuration that limits a minimum opening degree of the electric expansion valve when the humidity by the humidity sensor is high. Expansion valve control device for machine.