KR20010048759A - Method for controlling electric expansion valve of multi type air conditioner - Google Patents

Abstract

PURPOSE: An opening adjustment method of an expansion valve is provided to obtain the optimum cooling efficiency of each indoor unit by changing the opening of an expansion valve of a pre-running indoor unit properly depending on the current conditions when an additional other indoor unit is started. CONSTITUTION: A control unit checks the number of selected indoor units to be run and initializes the opening of each expansion valve of the selected indoor units. Then the control unit controls discharge of a compressor for keeping a refrigerating cycle with the optimum efficiency based on temperatures of a compressor discharge pipe. The control unit performs average control of discharge temperature of the indoor unit. If the discharge temperature falls, the opening of the expansion valve is increased and a large amount of refrigerant flows into a heat transfer pipe of an indoor heat exchanger. The control unit checks the number of selected indoor units again. If an indoor unit is added, the opening of a corresponding expansion valve is set based on user's set temperature. The opening of the plural expansion valves is adjusted individually depending on states of the current running indoor units. Therefore, an excess amount of refrigerant does not flow into the indoor heat exchanger.

Description

Method for controlling electric expansion valve of multi type air conditioner

The present invention relates to a method for adjusting the opening degree of the electric expansion valve of a multi-type air conditioner, in particular, when the operation of the indoor unit is additionally started during the operation of the device, so as to quickly and accurately adjust the current opening degree of the corresponding electric expansion valve. A method for adjusting the opening degree of an electric expansion valve of a multi-type air conditioner.

An air conditioner is a device that cools or heats a room by circulating a refrigerant between an indoor unit and an outdoor unit, and a refrigeration cycle is usually applied for cooling or heating. During the cooling operation of the refrigeration cycle, the refrigerant is vaporized in the heat exchanger of the indoor unit to absorb ambient heat, and the heat is released from the heat exchanger of the outdoor unit by liquefying the heat. At this time, if the cool air formed around the heat exchanger of the indoor unit is blown into the room, cooling of the room is achieved. On the other hand, in the heating operation of the refrigeration cycle is performed in the reverse order.

In such an air conditioner, it is common to use a single outdoor unit and an indoor unit. Recently, however, a multi-type air conditioner has been disclosed in which a plurality of indoor units are configured to correspond to one or more outdoor units in order to increase energy consumption efficiency.

Figure 1 is a block diagram showing the configuration of such a conventional multi-type air conditioner. As can be seen from the figure, the multi-type air conditioner 1 is composed of a single outdoor unit 3 and a plurality of indoor units 13, 15, 17. Hereinafter, for ease of explanation, a multi-type air conditioner in which three indoor units 13, 15, and 17 are connected to a single outdoor unit 3 will be described as an example. Next, the cooling operation of the multi-type air conditioner will be described.

The indoor units 13, 15, and 17 of each air conditioner have an operation unit 21, an indoor heat exchanger 12 for forming cold air, and a blower fan 14 for blowing cold air formed around the indoor heat exchanger 12. Is installed. Here, the address setting switch 23 which can set the unique address of each indoor unit 13, 15, 17 is provided. The user manipulates the operation of the device through the operation unit 21. Each indoor unit 13, 15, 17 also has an indoor unit control unit 27 and an indoor unit communication unit 29.

On the other hand, the outdoor unit 3 of a single air conditioner is provided with a compressor 6, an outdoor heat exchanger 5 for generating heat around it, and a cooling fan 7 for cooling the outdoor heat exchanger 5. . The outdoor unit 3 also has an outdoor unit communication unit 19. The outdoor unit communication unit 19 and each indoor unit communication unit 29 are connected to each other so as to exchange information.

The indoor units 13, 15, and 17 and the refrigeration cycle provided in the outdoor unit 3 are connected in a closed circulation by the refrigerant pipe 9. Each of the indoor heat exchanger inlet pipes 10 in the refrigerant pipe 9 is provided with electric expansion valves 11a, 11b, 11c for opening and closing the flow path of the refrigerant. The control part 27 controls the drive of the load drive parts 6, 7, 14 which form a refrigeration cycle, and the input / output of each communication part 19, 29 based on the operation signal from the operation part 21. As shown in FIG.

In the multi-type air conditioner 1 having such a configuration, after the user sets the unique address of each indoor unit 13, 15, 17 by using the address setting switch 23, the device can be operated. Then, the control unit 27 sequentially performs compressor discharge temperature control and indoor air outlet temperature average control at predetermined time intervals. Here, the compressor discharge temperature control is based on the temperature of the compressor discharge pipe 8 for discharging the high-temperature, high-pressure refrigerant from the compressor 6 regardless of the heat load in the room, to maintain the refrigeration cycle at an optimum efficiency.

On the other hand, the room in which the indoor units 13, 15, and 17 are installed does not have the same temperature, that is, their heat loads are maintained in different states. Thus, while performing the compressor discharge temperature control, the indoor heat exchanger 12 on one side requires a lot of refrigerant evaporation, while the indoor heat exchanger on the other side may have a relatively low amount of refrigerant evaporation. At this time, a change occurs in the outlet temperature of the indoor units 13, 15, 17 arranged in each room.

Then, the control unit 27 performs the average control of the indoor air outlet temperature. That is, in the indoor unit outlet temperature average control, the opening degree of the corresponding electric expansion valves 11a, 11b, 11c of the indoor units 13, 15, and 17 in which the indoor unit outlet temperature is reduced is further opened, and the inside of the heat exchanger tube of the indoor heat exchanger 12 is opened. It introduces a large amount of refrigerant. Further, the opening degree of the electric expansion valves 11a, 11b, 11c of the indoor units 13, 15, and 17 in which the indoor unit outlet temperature is increased is further closed, so that a small amount of refrigerant flows into the heat transfer tube of the indoor heat exchanger 14. do. Thereby, the indoor unit outlet temperature is appropriately adjusted.

By the way, in the multi-type air conditioner 1, it is possible to selectively operate a plurality of indoor units (13, 15, 17) according to the purpose of the user, at this time, according to the number of the indoor unit (13, 15, 17) operating The opening degree of the electric expansion valves 11a, 11b, 11c also changes. Figure 2 is an experimental diagram showing the opening value of the electric expansion valve appropriate to the temperature of the room and the number of the indoor unit. The control unit 27 stores such data.

Here, assume that the current temperature of the room is, for example, about 31 ° C to 33 ° C. In addition, it is assumed that the user can operate only two of the plurality of indoor units 13, 15, and 17, and at this time, the indoor temperature is set to 20 ° C. and 24 ° C., respectively. Then, the control unit 27, as can be seen in the diagram, first of all the electric expansion valve (11a, 11b) of the room temperature of 31 ℃ to 33 ℃ and 200 steps corresponding to the two indoor units (! 3, 15) Set the opening value.

Then, in order to maintain the room at the temperature set by the user, compressor discharge control and average control of the indoor air outlet temperature are sequentially performed. Then, the temperature of each room is gradually lowered to the temperature set by the user. At this time, the opening degree values of the electric expansion valves 11a and 11b also gradually change in the horizontal direction of the diagram in accordance with the change in the temperature of the room. So, for example, the opening value of the electric expansion valve 11a of the one indoor unit 13 in which the room temperature is set to 20 ° C is converted into 150 steps, and the electric expansion of the other indoor unit 15 set to 24 ° C is set. The opening value of the valve 11b is converted to 170 steps.

On the other hand, during operation of such a device, the user can operate the indoor unit 17 installed in another room. Thus, for example, when the operation of the other one indoor unit 17 is turned on, the control unit 27 controls all of the electric expansion valves 11a at an opening value corresponding to the temperature of the room where the newly operated indoor unit 27 is installed. , 11b, 11c) is set. That is, since the temperature of the room in which the indoor unit 17 to start driving is installed is about 31 ° C to 33 ° C, the opening values of all the electric expansion valves 11a, 11b, 11c are changed to 155 steps.

Then, the compressor discharge control and the indoor air outlet average control are performed, and through such control, each room is lowered to a temperature set by the user. At this time, the electric expansion valves 11a, 11b, 11c of each indoor unit 13, 15, 17 are also converted into opening values corresponding to the room temperature.

By the way, in the conventional expansion valve control method of the multi-type air conditioner 1, when the indoor unit 17 of any one side is further operated, the electric expansion valves 11a and 11b of the other indoor units 13 and 15 that are currently in operation. ), There is a problem that the opening value of the electric expansion valve 11c of the additional indoor unit 17 is set again to a value corresponding to the temperature of the room where the additional indoor unit 17 is installed. In this case, the motor-expanded valves 11a and 11b of the indoor units 13 and 15 which are in operation take a relatively long time to be restored to the opening value corresponding to the current temperature of the room. Thus, while the opening values of the electric expansion valves 11a and 11b are not appropriate, a suitable amount of refrigerant is not supplied to the indoor heat exchanger 14, so that frequent on / off states of the indoor units 13 and 15 occur. As a result, the cooling efficiency is lowered. In particular, when the amount of the refrigerant flowing into the compressor 6 is not constant, the overload of the compressor 6 may occur.

Accordingly, it is an object of the present invention, in view of such a conventional problem, that when the additional indoor unit is started, the opening degree of the electric expansion valve of the other indoor unit in operation is appropriately changed according to the current conditions, so that each indoor unit is optimal. It can be quickly restored to a state that can have a cooling efficiency of, and also to provide a method of controlling the opening degree of the multi-type air conditioner is less likely to cause overload of the compressor.

1 is a block diagram of a general multi-type air conditioner,

2 is a table showing the opening degree of the electric expansion valve with respect to the change in the operating number of the indoor unit and the temperature provided as an example to explain the method of adjusting the opening degree of the electric expansion valve of the conventional multi-type air conditioner,

Figure 3 is a flow chart illustrating a method of adjusting the opening degree of the electric expansion valve of the multi-type air conditioner according to the present invention, and

Figure 4 is a diagram showing the opening degree of the electric expansion valve with respect to the change in the operating number of the indoor unit and the temperature provided as an example to explain the method of adjusting the opening degree of the electric expansion valve of the multi-type air conditioner according to the present invention.

Explanation of symbols on the main parts of the drawings

5: outdoor heat exchanger 6: compressor

7: cooling fan 11a, 11b, 11c: electric expansion valve

12: indoor heat exchanger 13, 15, 17: indoor unit

27: control unit

The above object is, according to the present invention, in the method of controlling the opening degree of the electric expansion valve of the multi-type air conditioner having a plurality of indoor units and a plurality of electric expansion valves for adjusting the amount of refrigerant flowing into each indoor unit, the number of the indoor unit in operation Measure an appropriate opening value of the electric expansion valve with respect to the indoor unit number, and prepare predetermined data relating to the opening and closing value of the electric expansion valve with respect to the change of the indoor unit number based on the measured opening value. Doing; Checking the number of indoor units currently in operation; Checking whether the number of the indoor unit in operation is increased or decreased; And increasing and decreasing the indoor unit number, and applying the increase / decrease value in the data to the current opening value of the electric expansion valve.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. At this time, similarly to the above, the multi-type air conditioner having three indoor units will be described as an example, and thus, the detailed description of the multi-type air conditioner will be replaced by the above. In addition, the same code | symbol is used about the same structure and name as mentioned above.

Figure 3 is a flow chart illustrating a method of adjusting the opening degree of the electric expansion valve of the multi-type air conditioner according to the present invention. Before the operation of the device is started, the control unit 27 stores predetermined data as shown in the diagram of FIG. 4 (S1). First, with reference to the diagram, the conditions in the upper transverse direction indicate the room temperature, and the conditions in the left longitudinal direction indicate the change in the number of operating units of the indoor units 13, 15 and 17. The numbers in the center region are the opening and the closing values of the corresponding electric expansion valves 11a, 11b and 11c of the indoor unit in operation, with respect to the change in temperature and the number of operating units of the indoor units 13, 15 and 17. A description of the application of this diagram is given below in detail.

When the operation is started, the control unit 27 first checks the number of indoor units selected for operation (S2). Then, the opening value of the corresponding electric expansion valve of the selected indoor unit is initially set (S2). Here, the number of the selected indoor units is, for example, two (13, 15), as described in connection with the conventional FIG. 1, and their respective set temperatures are 20 ° C and 24 ° C, respectively. Assume that the current temperature is 31 ° C to 33 ° C. At this time, the initial setting of the motor-expansion valves 11a and 11b can be set to a predetermined experimental value with respect to the room temperature by applying the chart described with reference to FIG. 2. In this case, the initial opening value of each electric expansion valve 11a, 11b becomes 200 steps.

As such, when the initial setting of the electric expansion valves 11a and 11b is completed, the compressor discharge control is performed (S3). Compressor discharge control maintains a refrigeration cycle at an optimum efficiency based on the temperature of the compressor discharge pipe 8 which discharges the high temperature, high pressure refrigerant from the compressor 6 regardless of the heat load in the room. After the compressor discharge control proceeds for a predetermined time (S4), the indoor air outlet temperature average control is performed (S6).

In the indoor unit outlet temperature average control, when the indoor unit outlet temperature decreases, the opening degree of the electric expansion valve is further opened to introduce a large amount of refrigerant into the heat transfer tube of the indoor heat exchanger 12. In addition, when the indoor unit outlet temperature increases, the opening degree of the electric expansion valve is further closed to allow a small amount of refrigerant to flow into the heat transfer tube of the indoor heat exchanger.

Thus, while the indoor unit outlet temperature average control is in progress, the initially set opening values of the motor expansion valves 11a and 11b gradually change. Thus, the opening value of the electric expansion valve 11a of the indoor unit 13 at the set temperature of 20 ° C is 150 steps. And the opening value of the electric expansion valve 11b of the other indoor unit 15 whose set temperature is 24 degreeC becomes 170 steps.

On the other hand, after a predetermined time has elapsed (S7), the control unit 27 checks the number of the selected indoor unit (S8), and checks whether there is a change in the indoor unit (S9). At this time, if there is no change in the indoor unit number, the opening degree adjusting method of the electric expansion valve according to the present invention ends. By the way, if there is a change in the number of indoor units, for example, when the other one 17 is additionally started to operate, the opening degree of the electric expansion valves 11a, 11b, 11c is checked based on the stored data. .

That is, the two indoor units (13, 15) in operation from the three indoor units (13, 15, 17) was changed, at this time, the temperature of the room equipped with the additional indoor unit 17 is 31 ℃ to 33 ℃, As can be seen in the diagram of FIG. 4, the change value is −45 ° C. FIG. Thus, this value is applied to each of the electric expansion valves 11a and 11b (S10). Then, the opening value of the electric expansion valve 11a of the one indoor unit 13 which is currently being performed in 150 steps becomes 105 steps. Then, the opening value of the electric expansion valve 11b of the other indoor unit 15 being performed at 170 is 125 steps.

On the other hand, the opening value of the electric expansion valve 11c of the additional indoor unit 17 is set based on the temperature set by the user. Here, when the additional indoor unit 17 is set to 24 ° C, the controller sets the opening value of the electric expansion valve 11c to 125 steps.

In this way, in the present invention, the opening values of the respective electric expansion valves 11a, 11b and 11c are not applied equally as a whole but are individually adjusted according to the state of the indoor units 13 and 15 which are currently operating. Therefore, excessively inappropriate amount of refrigerant can be prevented from flowing into the indoor heat exchanger 14 during the adjustment of the electric expansion valves 11a and 11b and during the initial operation after the adjustment is completed.

On the other hand, when the individual opening adjustment of the electric expansion valve (11a, 11b, 11c) is completed (S10), the compressor discharge control (S4) and the indoor outlet temperature average control (S6) proceeds sequentially. Thus, the degree of opening of the electric expansion valves 11a, 11b, 11c of each indoor unit 13, 15, 17 is also readjusted to suit the room temperature.

As described above, according to the present invention, when the additional indoor unit is started, the opening degree of the electric expansion valve of the other indoor unit in operation is appropriately changed according to the present conditions, so that each indoor unit can have an optimal cooling efficiency. The present invention provides a method of controlling the opening degree of a multi-type air conditioner, which can be quickly restored to a state in which it is present, and the fear of overloading the compressor is reduced.

Claims (1)

In the opening degree adjustment method of the electric expansion valve of the multi-type air conditioner which has a some indoor unit and the some electric expansion valve which adjusts the amount of refrigerant which flows in each said indoor unit, Measuring an appropriate opening value of the electric expansion valve with respect to the indoor unit number by varying the number of operating indoor units, and based on the measured opening value, with respect to the opening and closing value of the electric expansion valve with respect to the change of the indoor unit number. Preparing predetermined data; Checking the number of indoor units currently in operation; Checking whether the number of the indoor unit in operation is increased or decreased; And And applying the increase / decrease value in the data to the current opening value of the electric expansion valve when increasing or decreasing the indoor unit number.