JPH07269977A - Motor operated expansion valve controller for air conditioner - Google Patents

Abstract

PURPOSE:To simultaneously obtain splitting of a refrigerant corresponding to an air conditioning load in indoor units and the capacity of an outdoor heat exchanger under conditions that superheat degree of a suction refrigerant gas of a compressor is not preferably controlled. CONSTITUTION:A difference of set temperatures of indoor sensors 2a, 2b and remote controllers 3a, 3b in indoor units 11a, 11b is detected, and limits of minimum openings of motor operated expansion valves 12a, 12b corresponding to the units 11a, 11b having different air conditioning loads are altered by a lowest opening deciding unit.

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 drawing, an inverter-controlled compressor 8 inside an outdoor unit 101, a four-way valve 9 for switching a refrigerant flow path, an outdoor heat exchanger 10, each indoor unit 1 are provided.
Electric expansion valve 1 of a refrigerant throttling mechanism corresponding to 1a and 11b
2a and 12b are provided.

In the above structure, the compressor 8 is operated by the indoor unit 11a, 11b in response to the operation command from the inverter unit 1
The refrigerant discharged from the compressor 8 through the four-way valve 9 is driven by the outdoor heat exchanger 10 during cooling, and the indoor heat exchanger 13 in the indoor units 11a and 11b during heating.
a, 13b, condensed by the electric expansion valves 12a, 12b, and the indoor heat exchangers 13a, 13b during cooling.
During heating, heat is exchanged in the outdoor heat exchanger 10 by the evaporation action, and the refrigeration cycle is returned to the compressor 8.

The operation command from the indoor units 11a and 11b is transmitted to the inverter unit 15 and the superheat control device 102 through the signal line 14, and the inverter unit 15 drives the compressor 8 by the signals from the indoor units 11a and 11b. The frequency is determined, and the superheat control device 102 causes the saturated temperature capillary tube 18 to move from the liquid receiver 17 at regular intervals.
Temperature sensor 21 attached to a bypass pipe 20 connected to a suction pipe 19 led out to the compressor 8 via
And a suction temperature sensor 22 attached to the suction pipe 19.
By detecting the temperature difference between them, the superheat degree of the entire refrigeration cycle is detected by the temperature difference, and the command line 23 transmits the opening / closing command to the electric expansion valves 12a, 12b via the superheat control device 15. It was adjusted to an appropriate degree of superheat.

[0007]

In such a conventional electric expansion valve control device for an air conditioner, the refrigerant pressure in the suction pipe 19 is 0.4 MPa or less and the refrigerant temperature is in the heating operation at low outside air temperature. Since the degree of superheat of the refrigerant cannot be taken in this state since it becomes 0 degree or less, the degree of opening of the electric expansion valves 12a and 12b is further reduced by trying to force the degree of superheat. Then, the refrigerant pressure in the suction pipe 19 falls too low before the superheat degree is taken, and the evaporation temperature of the outdoor heat exchanger 10 becomes zero degrees or less, so that the outdoor heat exchanger 10 freezes and the heating capacity is lost. , Conventionally electric expansion valve 1
The minimum opening of 2a and 12b was decided. However, a plurality of indoor units are operated, and the indoor units 11a, 11
Even when the air conditioning load differs between b, the electric expansion valve 12 corresponding to each indoor unit 11a, 11b
Since the minimum opening degrees of a and 12b are determined in advance, the amount of refrigerant supplied to the indoor units 11a and 11b can be the same as that of the electric expansion valves 12a and 1b regardless of the air conditioning load.
There is a problem in comfort and cost efficiency because it is uniformly limited by the minimum opening of 2b.

The present invention is to solve the above-mentioned problems. During heating operation, while controlling the degree of superheat, the refrigerant can be diverted according to the air conditioning load of each indoor unit without impairing the overall heating performance of the outdoor unit. It is a first object to provide an electric expansion valve control device for a multi-room air conditioner.

A second object is to provide an electric expansion valve control device for a multi-room air conditioner capable of finely dividing the refrigerant in accordance with the indoor air conditioning load judged by the degree of supercooling of each indoor unit. .

[0010]

In order to achieve the first object of the electric expansion valve control device for a multi-room air conditioner of the present invention, a first means is a compressor controlled by an inverter in an outdoor unit. And a four-way valve, an outdoor heat exchanger, a liquid receiver, and a plurality of electric expansion valves corresponding to each of the plurality of indoor units are provided to form a refrigeration cycle, and a saturation occurs between the liquid receiver and the suction pipe. Bypass pipe with capillary tube for temperature,
The suction pipe and the bypass pipe are respectively provided with a suction temperature sensor and a saturation temperature sensor, each indoor unit is provided with a room temperature sensor, and a remote controller for setting the indoor temperature, and the superheat degree is determined by the temperature difference between the suction temperature and the saturation temperature. A superheat control device for detecting, a difference between the indoor room temperature sensor and the set temperature of the remote control is detected for each indoor unit, and the minimum for determining the minimum opening degree of each of the plurality of electric expansion valves by the superheat control device. An opening degree determination device is provided.

In order to achieve the second object, the second
In this method, the indoor heat exchanger temperature sensor and the subcooling degree sensor on the liquid side of the indoor heat exchanger are provided in each of the plurality of indoor units, and the temperature difference between the indoor heat exchanger temperature and the liquid side temperature causes A supercooling degree control device for detecting cooling is provided, and the opening degree of the electric expansion valve corresponding to each indoor unit is determined by the supercooling degree control device.

[0012]

According to the first aspect of the present invention described above, in the simultaneous heating operation for a plurality of units when the outside air temperature is low, the superheat control is performed, and the air conditioning load is different due to the difference in the air conditioning loads of the plurality of indoor units. Since it is possible to narrow down the heating capacity of the indoor unit having a small air conditioning, the heating capacity of the indoor unit having a large air conditioning load can be maintained.

Further, according to the structure of the second means, in the simultaneous heating operation of a plurality of units when the outside air temperature is low, the superheat degree is controlled and the electric expansion corresponding to each indoor unit is performed according to the degree of supercooling of the indoor unit. Since the opening of the valve is adjusted, especially when the refrigerant piping is long piping, the amount of refrigerant in the entire refrigeration cycle tends to be inadequate and it is difficult to supercool, but depending on the subcooling of each indoor unit In addition, since the refrigerant is divided in a fine manner, it is possible to finely control the heating capacity.

[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 units 11a, 1
Room temperature sensors 2a, 2b and remote controllers 3a, 3 in 1b
b, the suction temperature sensor 22 and the saturation temperature sensor 21 in the outdoor unit 7 are provided, and the indoor room temperature sensor 2
A minimum opening degree determining device 1a, 1b is provided which changes the minimum opening degree corresponding to each of the electric expansion valves 12a, 12b according to the set temperature difference between a and 2b and the remote controllers 3a, 3b.

With the above-mentioned configuration, when a plurality of indoor units are in the heating operation at the same time, the value of the temperature difference between the suction temperature sensor 22 and the saturation temperature sensor 21 is transmitted to the superheat control device 16 to control the superheat. Then, when the outside air temperature is low, since the degree of superheat cannot be obtained, the electric expansion valve 12a,
Although 12b is narrowed down to the minimum opening degree, the superheat degree control is practically impossible, and the control of the refrigerant flow rate for each indoor unit is also limited to the minimum opening degree. When the indoor units 105a having a large difference in set temperature and the indoor units 105b having a small difference in set temperature among the remote controllers 3a and 3b are simultaneously performing heating operation, the minimum opening degree determining devices 1a and 1b are used to minimize the electric expansion valve 12b having a small air conditioning load. The electric expansion valve 12a having a large air-conditioning load is changed so that the opening degree is further narrowed, and conversely, the opening degree is changed so as to be further opened. The outdoor heat exchanger 10 can be operated properly, maximize the capacity of the outdoor heat exchanger 10, and can be efficiently operated.

As described above, according to the electric expansion valve control device for a multi-room air conditioner of the first embodiment of the present invention, even if the superheat control does not work effectively because the outside air temperature is low, the indoor unit In addition to performing superheat control according to the air conditioning load,
Optimal refrigerant diversion can be performed for each indoor unit.

(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 indoor units 11a, 1
On the liquid side of the indoor heat exchangers 13a, 13b in 1b, the subcooling degree sensors 4a, 4b and the indoor heat exchanger temperature sensor 5a,
5b is provided, the superheat degree control by detecting the temperature difference from the suction temperature sensor 22 and the saturation temperature sensor 21 provided in the suction pipe 19 in the outdoor unit 7, and the supercooling degree sensor 4
A configuration in which the degree of supercooling is detected by the temperature difference between a and 4b and the indoor heat exchanger temperature sensors 5a and 5b, and the opening degree of the electric expansion valves 12a and 12b is controlled by the supercooling control by the supercooling degree control device 6. And

With the above structure, a plurality of indoor units 1
When 1a and 11b are in the heating operation at the same time, the value of the detected temperature difference between the suction temperature sensor 22 and the saturation temperature sensor 21 is transmitted to the superheat degree control device 16, and the superheat degree control is performed. , It is possible to obtain almost no superheat, but by detecting the supercooling degree, each indoor unit 11
By determining the difference in the air-conditioning load between a and 11b, and adjusting the opening degree of each of the electric expansion valves 12a and 12b corresponding to each indoor unit individually during the heating operation at low outside air temperature when the superheat degree cannot be controlled, The flow rate can be controlled finely and appropriately,
In addition, the capacity of the outdoor heat exchanger 10 can be maximized, and efficient operation can be achieved even when the refrigerant pipe is long.

As described above, according to the electric expansion valve control device for a multi-room air conditioner of the second embodiment of the present invention, even if the superheat control does not work effectively because the outside air temperature is low, the refrigerant pipe Regardless of the length, the opening degree of the electric expansion valve provided in each indoor unit is adjusted in accordance with the air conditioning load determined by the difference in the degree of supercooling of the indoor unit, so that the optimum refrigerant shunt can be achieved.

[0022]

As is apparent from the above embodiments, according to the present invention, the superheat degree control device for detecting the temperatures of the suction temperature sensor and the saturation temperature sensor of the compressor, the room temperature sensor and the remote controller. Detects the temperature difference,
By determining the air conditioning load of each indoor unit and controlling the minimum opening by the minimum opening control device in the outdoor unit, the air conditioning of the indoor unit is achieved even during heating operation at low outside air temperature while maintaining superheat. It is possible to provide an electric expansion valve control device for a multi-room air conditioner that can perform optimal refrigerant distribution according to a load and efficiently exhibit the outdoor heat exchanger capacity.

Further, by detecting the degree of supercooling of each indoor unit, the supercooling control is performed by the degree of supercooling control device,
Even when the refrigerant pipe is a long pipe, it is possible to provide the electric expansion valve control device of the air conditioner that can perform the optimum refrigerant distribution according to each indoor air conditioning load and can maximize the outdoor heat exchanger capacity.

[Brief description of drawings]

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

FIG. 2 is a refrigeration cycle diagram of the second embodiment.

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

[Explanation of Codes] 1 Minimum opening determination device 2a Room temperature sensor 2b Room temperature sensor 3a Remote control 3b Remote control 4a Supercooling degree sensor 4b Supercooling degree sensor 5a Indoor heat exchanger temperature sensor 5b Indoor heat exchanger temperature sensor 6 Supercooling degree control Device 7 Outdoor unit 8 Compressor 9 Four-way valve 10 Outdoor heat exchanger 11a Indoor unit 11b Indoor unit 12a Electric expansion valve 12b Electric expansion valve 13a Indoor heat exchanger 13b Indoor heat exchanger 16 Superheat control device 17 Liquid receiver 18 Saturation Capillary tube for temperature 19 Suction pipe 20 Bypass pipe 21 Saturation temperature sensor 22 Suction temperature sensor

Claims (2)

[Claims] 1. A refrigeration cycle comprising a compressor controlled by an inverter, a four-way valve, an outdoor heat exchanger, a liquid receiver, and a plurality of electric expansion valves corresponding to a plurality of indoor units in an outdoor unit. Then, a bypass pipe having a saturation temperature capillary tube between the liquid receiver and the suction pipe, and a suction temperature sensor and a saturation temperature sensor are provided in the suction pipe and the bypass pipe, respectively, in each indoor unit Equipped with a room temperature sensor and a remote control to set the room temperature,
A superheat control device that detects a superheat by a temperature difference between a suction temperature and a saturation temperature, a difference between the indoor room temperature sensor and the set temperature of the remote controller is detected for each indoor unit, and the plurality of superheat control devices operate. An electric expansion valve control device for a multi-chamber air conditioner, which is provided with a minimum opening degree determination device that determines the minimum opening degree of each electric expansion valve. 2. An indoor heat exchanger temperature sensor and a subcooling degree sensor on the liquid side of the indoor heat exchanger are provided in each of the plurality of indoor units, and the temperature difference between the indoor heat exchanger temperature and the liquid side temperature causes the temperature difference between the indoor heat exchanger temperature sensor and the liquid side temperature, respectively. 2. A multi-chamber air conditioner according to claim 1, wherein a supercooling degree control device for detecting supercooling is provided, and the degree of opening of the electric expansion valve corresponding to each indoor unit is determined by the supercooling degree control device. Expansion valve control device for machine.