Air conditioner

Abstract

This air conditioner comprises: a compressor having a compressor suction pipe and a compressor discharge pipe connected; an outdoor heat exchanger having a liquid pipe and a connection pipe connected; a first flow path switching valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the connection pipe; a second flow path switching valve connected to each of the compressor suction pipe, the compressor discharge pipe, and a high pressure gas pipe; a third flow path switching valve connected to each of the compressor suction pipe, the compressor discharge pipe, and a low pressure gas pipe; an outdoor expansion valve installed on the liquid pipe; a first indoor unit connected to the liquid pipe and the high pressure gas pipe; a second indoor unit connected to the liquid pipe and the low pressure gas pipe; a first opening degree adjusting valve disposed on the high pressure gas pipe; and a second opening degree adjusting valve disposed on the low pressure gas pipe, wherein the first opening degree adjusting valve and the second opening degree adjusting valve may be controlled according to the respective operation modes and set temperatures of the first indoor unit and the second indoor unit.

Description

air conditioner

[0001] The present invention relates to an air conditioner.

[0002] An air conditioner is a heating and cooling device that transfers a low-temperature heat source to a high-temperature one or transfers a high-temperature heat source to a low-temperature one by using the heat generation or condensation heat of a refrigerant.

[0003] An air conditioner may include a refrigeration cycle, and may cool or heat a room by including a compressor that compresses a refrigerant, a heating / cooling switching valve that switches between cooling and heating operations by changing the flow direction of the refrigerant, an outdoor heat exchanger that exchanges heat between the refrigerant and outdoor air, an expansion device that expands the refrigerant, and an indoor heat exchanger that exchanges heat between the refrigerant and indoor air.

[0004] Conventional air conditioners, because they cool or heat entire rooms, have limitations in meeting the air conditioning needs of each room. To address this issue, research is currently underway on simultaneous cooling and heating multi-unit air conditioners, where some indoor units perform cooling operations while others perform heating operations.

[0005] Korean Patent Publication No. 10-2022-0006336 A (published on January 17, 2022) discloses a simultaneous cooling and heating air conditioner, comprising: an outdoor unit including a compressor for compressing a refrigerant; and an outdoor heat exchanger for heat-exchanging the refrigerant with outdoor air; indoor units each including one or more indoor heat exchangers; and distributors disposed between the outdoor unit and the indoor units to distribute the refrigerant to the indoor units according to operating conditions.

[0006] The distributor is connected to the outdoor unit through a liquid pipe, a high-pressure refrigerant pipe, and a low-pressure refrigerant pipe, and is connected to each of the indoor unit's heat exchangers and the indoor engine.

[0007] The distributor includes a liquid refrigerant header connecting the liquid pipes and each of the plurality of heat exchangers, a high-pressure refrigerant header connecting the high-pressure refrigerant pipes and each of the plurality of heat exchangers, and a low-pressure refrigerant header connecting the low-pressure refrigerant pipes and each of the plurality of heat exchangers.

[0008] Each of the multiple indoor units is provided with a control valve that regulates the flow of refrigerant. The control valve includes a high-pressure valve and a low-pressure valve.

[0009] Air conditioners according to conventional technology have problems in that the installation piping can be complicated due to the distributor, a separate space is required for the distributor, and the installation cost increases due to an increase in welding points.

[0010] Air conditioners according to conventional technology have a problem in that, when multiple indoor units are placed in different zones, it is difficult to control the outlet temperature of each indoor unit placed in different zones differently.

[0011] The present embodiment provides an air conditioner capable of minimizing installation costs.

[0012] The present embodiment provides an air conditioner that controls multiple indoor units placed in different zones to different temperatures with a simple structure and control.

[0013] An air conditioner according to the present embodiment includes a compressor having a compressor suction pipe and a compressor discharge pipe connected thereto; an outdoor heat exchanger having a liquid pipe and a connection pipe connected thereto; a first flow-change valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the connection pipe; a second flow-change valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the high-pressure engine; a third flow-change valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the low-pressure engine; an outdoor expansion valve installed in the liquid pipe; a first indoor unit connected to the liquid pipe and the high-pressure engine; a second indoor unit connected to the liquid pipe and the low-pressure engine; a first opening control valve disposed in the high-pressure engine; and a second opening control valve disposed in the low-pressure engine, wherein the first opening control valve and the second opening control valve can be controlled according to the operation mode and the set temperature of each of the first indoor unit and the second indoor unit.

[0014] The compressor suction pipe may include a common suction pipe in which an accumulator is arranged; a first combined pipe connected to the common suction pipe and a first directional changeover valve; a second combined pipe connected to the common suction pipe and a second directional changeover valve; and a third combined pipe connected to the common suction pipe and a third directional changeover valve.

[0015] The compressor discharge pipe may include a common discharge pipe having an oil separator arranged therein; a first branch pipe connected to a first directional valve; a second branch pipe connected to the common discharge pipe and a second directional valve; and a third branch pipe connected to the common discharge pipe and a third directional valve.

[0016] One end of the first branch pipe may be connected to one of the second branch pipe and the third branch pipe, and the other end of the first branch pipe may be connected to the first euro changeover valve.

[0017] The liquid pipe may include a common liquid pipe having an outdoor expansion valve arranged thereon; a first branch liquid pipe connected to each of the common liquid pipe and the first indoor unit; and a second branch liquid pipe connected to each of the common liquid pipe and the second indoor unit.

[0018] The first opening control valve and the second opening control valve may be electronic expansion valves.

[0019] The air conditioner may further include a control unit that controls the compressor, the first euro switching valve, the second euro switching valve, the third euro switching valve, the first opening control valve, and the second opening control valve.

[0020] If the operation mode of each of the first indoor unit and the second indoor unit is the heating mode, the first opening control valve and the second opening control valve can be fully open.

[0021] If the difference between the set temperature of the first indoor unit and the set temperature of the second indoor unit is less than the set value, the first opening control valve and the second opening control valve can be fully open.

[0022] If the outside temperature is higher than the set outside temperature, the first opening control valve and the second opening control valve may be fully open.

[0023] If the operation mode of each of the first indoor unit and the second indoor unit is the cooling mode and the difference between the set temperature of the first indoor unit and the set temperature of the second indoor unit is greater than the set value, the opening degree of the opening degree control valve corresponding to the indoor unit with the higher set temperature among the first opening degree control valve and the second opening degree control valve can be reduced.

[0024] When the operation mode of each of the first indoor unit and the second indoor unit is the cooling mode and the outside temperature is lower than the set temperature, at least one of the first opening control valve and the second opening control valve can be adjusted to control the flow rate.

[0025] The control unit can perform a first process of calculating a representative set temperature, a current dew point temperature, and a current pipe inlet temperature for each zone if there is a cooling zone among the zones where the first indoor unit is placed and the zones where the second indoor unit is placed; a second process of calculating a target pipe inlet temperature for each zone if all zones are cooling and the cooling set temperatures of the zones are different; and a third process of controlling an opening control valve corresponding to a zone having the highest target pipe inlet temperature among the target pipe inlet temperatures calculated for each zone, according to the pipe inlet temperature.

[0026] If all zones are not cooling zones, and the current pipe inlet temperature is lower than the current dew point temperature or freezing temperature, the control unit can perform a fourth step of setting the target pipe inlet temperature of the cooling zone to a set temperature higher than the current dew point temperature.

[0027] The control unit may change the system target evaporation pressure according to the target pipe inlet temperature of a zone that is not the highest among the target pipe inlet temperatures calculated for each zone, or, if no zone is refrigerated and the current pipe inlet temperature is higher than the current dew point temperature or freezing temperature, may perform a fifth process of changing the system target evaporation pressure according to the current pipe inlet temperature.

[0028] According to this embodiment, multiple zones can be simultaneously heated or cooled without a separate distributor, and when the set temperature is different for each zone, different evaporation pressures can be formed for each zone through the simple structure of the first or second opening control valve and the control of the first or second opening control valve, thereby providing greater comfort to the user.

[0029] In addition, by setting the target pipe inlet temperature of the cooling zone to a temperature higher than the current dew point temperature, condensation or freezing of the indoor heat exchanger can be minimized, and reliability is high.

[0030] Figure 1 is a diagram of an air conditioner according to the present embodiment.

[0031] Figure 2 is an enlarged view of the outdoor unit shown in Figure 1.

[0032] Figure 3 is a control block diagram of an air conditioner according to the present embodiment.

[0033] Figure 4 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in cooling-only operation.

[0034] Figure 5 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in heating-only operation.

[0035] Figure 6 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in cooling operation.

[0036] Figure 7 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in heating-main operation.

[0037] Figure 8 is a flowchart illustrating a method of operating an air conditioner according to the present embodiment.

[0038] Fig. 9 is a diagram showing the target pipe inlet temperature according to the set temperature when the set temperatures of the zones according to the present embodiment are different.

[0039] Hereinafter, specific embodiments of the present invention will be described in detail with drawings.

[0040] Fig. 1 is a diagram of an air conditioner according to the present embodiment, and Fig. 2 is an enlarged diagram of the outdoor unit illustrated in Fig. 1.

[0041] An air conditioner according to the present embodiment may include an outdoor unit (O) and a plurality of indoor units (I), as illustrated in FIG. 1.

[0042] The air conditioner can selectively perform cooling-only operation, heating-only operation, cooling-only operation, and heating-only operation.

[0043] Cooling-only operation may be an operation in which all of the indoor units (I) are in cooling mode, heating-only operation may be an operation in which all of the indoor units (I) are in heating mode, cooling-main operation may be an operation when the cooling load is greater than the heating load, and cooling-main operation may be an operation when the heating load is greater than the cooling load.

[0044] The air conditioner can perform cooling-based operation when the capacity of the indoor unit in cooling operation among multiple indoor units (I) is greater than the capacity of the indoor unit in heating operation among multiple indoor units (I).

[0045] The air conditioner can perform heating operation when the capacity of the indoor unit in heating operation among multiple indoor units (I) is greater than the capacity of the indoor unit in cooling operation among multiple indoor units (I).

[0046] The air conditioner can control multiple zones (Z1, Z2). Multiple indoor units (I) can be distributed and placed in multiple zones (Z1, Z2).

[0047] The number of multiple zones (Z1, Z2) is not limited, but the following description assumes that the air conditioner controls two zones.

[0048] The indoor unit installed in the first zone (Z1) among the plurality of zones (Z1, Z2) is referred to as the first indoor unit (Ia, Ib), and the indoor unit installed in the second zone (Z2) among the plurality of zones (Z1, Z2) is referred to as the second indoor unit (Ic, Id).

[0049] A plurality of first indoor units (Ia, Ib) may be placed in the first zone (Z1), and the plurality of first indoor units (Ia, Ib) may be controlled to different set temperatures (target temperatures). Of course, it is also possible to place a single first indoor unit in the first zone (Z1).

[0050] When a plurality of first indoor units (Ia, Ib) are arranged in a first zone (Z1) and the plurality of first indoor units (Ia, Ib) are operated at different set temperatures, the plurality of first indoor units (Ia, Ib) installed in the first zone (Z1) can be controlled based on a representative set temperature (first representative set temperature). An example of the representative set temperature (first representative set temperature) may be an average temperature of the set temperatures of the first indoor units (Ia, Ib).

[0051] A plurality of second indoor units (Ic, Id) can be placed in the second zone (Z2), and the plurality of second indoor units (Ic, Id) can be controlled to different set temperatures (target temperatures). Of course, it is also possible to place a single second indoor unit in the second zone (Z2).

[0052] When a plurality of second indoor units (Ic, Id) are arranged in a second zone (Z2) and the plurality of second indoor units (Ic, Id) are operated at different set temperatures, the plurality of second indoor units (Ic, Id) installed in the second zone (Z2) can be controlled based on a representative set temperature (second representative set temperature). An example of the representative set temperature (second representative set temperature) may be an average temperature of the set temperatures of the second indoor units (Ic, Id).

[0053] An air conditioner may include a compressor (1), an outdoor heat exchanger (2), an outdoor fan (3), multiple flow switching valves, and multiple opening control valves. The compressor (1), the outdoor heat exchanger (2), the outdoor fan (3), multiple flow switching valves, and multiple opening control valves may constitute an outdoor unit (O) installed outdoors.

[0054] The multiple-euro switching valve may be a valve that switches the flow direction of the refrigerant according to cooling operation, heating operation, dedicated operation, and main operation.

[0055] The multiple euro switching valve may include a first euro switching valve (4); a second euro switching valve (5) and a third euro switching valve (6).

[0056] The multiple opening control valve may include a first opening control valve (7) and a second opening control valve (8).

[0057] The air conditioner can simultaneously cool or heat multiple indoor units (I) by means of three Euro switching valves (4, 5, 6), and can cool or heat multiple zones (Z1, Z2) at different temperatures by means of two opening control valves (7, 8).

[0058] The first euro switching valve (4) can switch the refrigerant flow path so that the refrigerant compressed in the compressor (1) flows to the outdoor heat exchanger (2) during cooling operation (cooling-only operation and cooling-main operation).

[0059] The first euro switching valve (4) can switch the refrigerant flow path so that the refrigerant evaporated in the outdoor heat exchanger (2) flows to the compressor (1) during heating operation (heating-only operation and heating main operation).

[0060] The first euro switching valve (4) may be a heating / cooling switching valve that can switch the outdoor unit (O) between cooling operation and heating operation.

[0061] The second euro switching valve (5) can switch the refrigerant flow path so that the refrigerant flowing from at least one of the first and second opening control valves (7)(8) flows to the compressor (1) during cooling operation (cooling-only operation and cooling-main operation) and heating-main operation.

[0062] The second euro switching valve (5) can switch the refrigerant flow path so that the refrigerant compressed in the compressor (1) flows to the first and second opening control valves (7)(8) during heating-only operation.

[0063] The third euro switching valve (6) can switch the refrigerant flow path so that the refrigerant flowing from at least one of the first and second opening control valves (7)(8) flows to the compressor (1) during cooling-only operation.

[0064] The third euro switching valve (6) can switch the refrigerant flow path so that the refrigerant compressed in the compressor (1) flows to at least one of the first and second opening control valves (7)(8) during cooling-only operation and heating operation (heating-only operation and heating-only operation).

[0065] A compressor suction pipe (11) and a compressor discharge pipe (16) can be connected to the compressor (1).

[0066] The compressor (1) can compress refrigerant sucked in through the compressor suction pipe (11) and discharge the compressed refrigerant through the compressor discharge pipe (16).

[0067] The compressor suction pipe (11) may include a common suction pipe (12), a first joint pipe (13), a second joint pipe (14), and a third joint pipe (15).

[0068] An accumulator (12a) can be placed in the common suction pipe (12).

[0069] The common suction pipe (12) may include a first suction pipe (12b) that guides refrigerant to an accumulator (12a), as shown in FIG. 2, and a second suction pipe (12c) that guides refrigerant from the accumulator (12a) to a compressor suction port.

[0070] The first suction pipe (12b) can be connected to a merging point where at least two of the first joint pipe (13), the second joint pipe (14), and the third joint pipe (15) are joined, and to an accumulator (12a).

[0071] The second suction pipe (12c) can be connected to the accumulator (12a) and the compressor suction port, respectively.

[0072] The first joint pipe (13) can be connected to the common suction pipe (12) and the first euro switching valve (4).

[0073] The second joint pipe (14) can be connected to the common suction pipe (12) and the second euro switching valve (5).

[0074] The second joint pipe (14) can be joined to the first joint pipe (13) or the third joint pipe (15). One end of the second joint pipe (14) can be connected to the second euro switching valve (5), and the other end of the second joint pipe (14) can be connected to the first joint pipe (13).

[0075] The third joint pipe (15) can be connected to the common suction pipe (12) and the third euro switching valve (6).

[0076] The third joint pipe (15) can be joined to the first joint pipe (13) or the second joint pipe (14). One end of the third joint pipe (15) can be connected to the third euro switching valve (6), and the other end of the third joint pipe (15) can be connected to the first joint pipe (13).

[0077] The compressor discharge pipe (16) may include a common discharge pipe (17), a first branch pipe (18), a second branch pipe (19), and a third branch pipe (20).

[0078] An oil separator (17a) can be placed in the common discharge pipe (17).

[0079] As shown in Fig. 2, the common discharge pipe (17) may include a first discharge pipe (17b) that guides the refrigerant discharged from the compressor (1) to an oil separator (17a), and a second discharge pipe (17c) that guides the refrigerant of the oil separator (17a) to a second branch pipe (19) and a third branch pipe (20).

[0080] The first discharge pipe (17b) can be connected to the discharge port of the compressor (1) and the oil separator (17a).

[0081] One end of the second discharge pipe (17c) can be connected to an oil separator (17a). The other end of the second discharge pipe (17c) can be connected to a branch point (17d) of the second branch pipe (19) and the third branch pipe (20).

[0082] The first branch pipe (18) can be connected to the third branch pipe (20) and the first flow switching valve (4). One end of the first branch pipe (18) can be connected to one of the second branch pipe (19) and the third branch pipe (20), and the other end of the first branch pipe (18) can be connected to the first flow switching valve (4). The first branch pipe (18) can guide the refrigerant to the first flow switching valve (4).

[0083] The second branch pipe (19) can be connected to the common discharge pipe (17) and the second flow switching valve (5). One end of the second branch pipe (19) can be connected to the branch point (17d), and the other end of the second branch pipe (19) can be connected to the second flow switching valve (5). The second branch pipe (19) can guide the refrigerant to the second flow switching valve (5).

[0084] The third branch pipe (20) can be connected to the common discharge pipe (17) and the third flow switching valve (6). One end of the third branch pipe (20) can be connected to the branch point (17d), and the other end of the third branch pipe (20) can be connected to the third flow switching valve (6). The third branch pipe (20) can guide the refrigerant to the third flow switching valve (6).

[0085] A liquid pipe (21) can be connected to one side of the outdoor heat exchanger (2).

[0086] The liquid pipe (21) may include a common liquid pipe (22), a first branch liquid pipe (23) connected to the first indoor unit (Ia, Ib), and a second branch liquid pipe (24) connected to the second indoor unit (Ic, Id).

[0087] The first branch pipe (23) can be connected to the first pipe (93) of the first indoor unit (Ia, Ib).

[0088] The first branch pipe (24) can be connected to the first pipe (93) of the second indoor unit (Ic, Id).

[0089] The air conditioner may include an expansion valve disposed in a liquid pipe (21). The expansion valve may include an outdoor expansion valve (25) disposed in a common liquid pipe (22). An example of the outdoor expansion valve (25) may include an electronic expansion valve (EEV).

[0090] A connecting pipe (28) can be connected to the other side of the outdoor heat exchanger (2).

[0091] The connecting pipe (28) can connect the outdoor heat exchanger (2) and the first euro switching valve (4).

[0092] The connecting pipe (28) can guide the refrigerant flowing from the first flow switching valve (4) to the outdoor heat exchanger (2). The connecting pipe (28) can guide the refrigerant flowing from the outdoor heat exchanger (2) to the first flow switching valve (4).

[0093] The first euro switching valve (4) can be connected to each of the compressor suction pipe (11), the compressor discharge pipe (16), and the connecting pipe (28).

[0094] The first euro switching valve (4) can be connected to the first joint pipe (13) of the compressor suction pipe (11).

[0095] The first euro switching valve (4) can be connected to the first branch pipe (17) of the compressor discharge pipe (16).

[0096] The refrigerant discharged from the compressor (1) can sequentially pass through the third branch pipe (20) and the first branch pipe (17) and flow into the first flow switching valve (4).

[0097] The first euro switching valve (4) may have three ports. The first euro switching valve (4) may include a first branch pipe port to which the first branch pipe (13) is connected. The first euro switching valve (4) may include a first branch pipe port to which the first branch pipe (17) is connected. The first euro switching valve (4) may include a connection pipe port to which the connection pipe (28) is connected.

[0098] The first euro switching valve (4) can be controlled in a compressor supply mode that guides the refrigerant to the compressor (1). In the compressor supply mode, the first euro switching valve (4) can guide the refrigerant flowing in the connecting pipe (28) to the first joint pipe (13).

[0099] The first flow switching valve (4) can be controlled in an outdoor heat exchanger supply mode that guides refrigerant to the outdoor heat exchanger (2). In the outdoor heat exchanger supply mode, the first flow switching valve (4) can guide refrigerant introduced through the first branch pipe (17) from the third branch pipe (20) to the connecting pipe (28).

[0100] The first euro switching valve (4) may be an outdoor heat exchanger switching valve (or heating / cooling switching valve) that determines the flow direction of the refrigerant flowing to the outdoor heat exchanger (2).

[0101] The second euro switching valve (5) can be connected to each of the compressor suction pipe (11), the compressor discharge pipe (16), and the high pressure engine (51).

[0102] The second euro switching valve (5) can be connected to the second joint pipe (14) of the compressor suction pipe (11).

[0103] The second euro switching valve (5) can be connected to the second branch pipe (19) of the compressor discharge pipe (16).

[0104] The second euro switching valve (5) may have three ports. The second euro switching valve (5) may include a second branch pipe port to which the second branch pipe (14) is connected. The second euro switching valve (5) may include a third branch pipe port to which the second branch pipe (19) is connected. The second euro switching valve (5) may include a high pressure engine port to which the high pressure engine (51) is connected.

[0105] The second euro switching valve (5) can be controlled in a compressor supply mode that guides refrigerant to the compressor. In the compressor supply mode, the second euro switching valve (5) can guide refrigerant introduced from the high-pressure engine (51) to the second composite pipe (14).

[0106] The second euro switching valve (5) can be controlled in a high-pressure engine supply mode that guides the refrigerant to the high-pressure engine (51). In the high-pressure engine supply mode, the second euro switching valve (5) can guide the refrigerant flowing in the second branch pipe (19) to the high-pressure engine (51).

[0107] The second euro switching valve (5) may be a first opening control valve switching valve (or a cooling / heating switching valve) that determines the flow direction of the refrigerant flowing to the first opening control valve (7).

[0108] The third euro switching valve (6) can be connected to each of the compressor suction pipe (11), the compressor discharge pipe (16), and the low pressure engine (61).

[0109] The third euro switching valve (6) can be connected to the third joint pipe (15) of the compressor suction pipe (11).

[0110] The third euro switching valve (6) can be connected to the third branch pipe (20) of the compressor discharge pipe (16).

[0111] The third euro switching valve (6) may have three ports. The third euro switching valve (6) may include a third branch pipe port to which the third branch pipe (15) is connected. The third euro switching valve (6) may include a third branch pipe port to which the third branch pipe (20) is connected. The third euro switching valve (6) may include a low pressure engine port to which the low pressure engine (61) is connected.

[0112] The third euro switching valve (6) can be controlled in a compressor supply mode that guides the refrigerant to the compressor (1). In the compressor supply mode, the third euro switching valve (6) can guide the refrigerant guided to the low pressure engine (61) to the third joint pipe (15).

[0113] The third euro switching valve (6) can be controlled in a low-pressure engine supply mode that guides the refrigerant to the low-pressure engine (61). In the low-pressure engine supply mode, the third euro switching valve (6) can guide the refrigerant guided from the compressor third branch pipe (20) to the low-pressure engine (61).

[0114] The third euro switching valve (6) may be a second opening control valve switching valve (or heating / cooling switching valve) that determines the flow direction of the refrigerant flowing to the second opening control valve (8).

[0115] The first opening control valve (7) can be placed in the high pressure engine (51).

[0116] The refrigerant compressed in the compressor (1) can flow to the first indoor unit (Ia, Ib) by passing through the high-pressure engine (51) and the first opening control valve (7).

[0117] The refrigerant flowing in the first indoor unit (Ia, Ib) can pass through the high-pressure engine (51) and the first opening control valve (7) and be guided to the second flow switching valve (5).

[0118] The first opening control valve (7) may be an opening control valve whose opening degree (opening degree) can be controlled, and may be, for example, an electronic expansion valve (EEV).

[0119] The first opening control valve (7) can be controlled to be fully open, which is the maximum opening, and the opening can be reduced by the set opening amount from the fully open state.

[0120] The first opening control valve (7) can adjust the opening in at least four stages.

[0121] The first opening control valve (7) can control the flow rate of refrigerant flowing into the first indoor unit (Ia, Ib) by adjusting the opening.

[0122] The first opening control valve (7) may be a first flow control valve capable of controlling the flow rate of refrigerant passing through the high-pressure engine (51), and may be a first pressure control valve capable of controlling the evaporation pressure of the indoor heat exchanger (91) of the first indoor unit (1a, 1b).

[0123] The second opening control valve (8) can be placed in the low pressure engine (61).

[0124] The refrigerant compressed in the compressor (1) can flow to the second indoor unit (Ic, Id) by passing through the low pressure unit (61) and the second opening control valve (8).

[0125] The refrigerant flowing in the second indoor unit (Ic, Id) can pass through the low pressure unit (61) and the second opening control valve (8) and be guided to the third flow switching valve (6).

[0126] The second opening control valve (8) may be an opening control valve whose opening degree can be adjusted, and may be, for example, an electronic expansion valve (EEV).

[0127] The second opening control valve (8) can be controlled to be fully open, which is the maximum opening, and from the fully open state, the opening can be reduced by the set opening amount.

[0128] The second opening control valve (8) can adjust the opening in at least four stages.

[0129] The second opening control valve (8) can control the flow rate of refrigerant flowing to the second indoor unit (Ic, Id) by adjusting the opening.

[0130] The second opening control valve (8) may be a second flow control valve capable of controlling the flow rate of refrigerant passing through the low pressure engine (61), and may be a second pressure control valve capable of controlling the evaporation pressure of the indoor heat exchanger (91) of the second indoor unit (1c, 1d).

[0131] That is, the air conditioner can control the amount of refrigerant flowing to multiple indoor units (I) by the first opening control valve (7) and the second opening control valve (8).

[0132] Each of the plurality of indoor units (I) may include an indoor heat exchanger (91) through which refrigerant passes, an indoor fan (92) for blowing indoor air to the indoor heat exchanger (91), a first pipe (93) connected to one side of the indoor heat exchanger (91), a second pipe (95) connected to the other side of the indoor heat exchanger (91), and an indoor expansion valve (94) arranged in the first pipe (93) or the second pipe (95).

[0133] The first pipe (93) can be connected to the liquid pipe (21).

[0134] An indoor expansion valve (94) can be placed in the first pipe (93).

[0135] The second pipe (95) can be connected to a high pressure engine (51) or a low pressure engine (61).

[0136] The high pressure engine (51) can be connected to the second pipe (95) of the first indoor unit (Ia, Ib).

[0137] The low pressure unit (61) can be connected to the second pipe (95) of the second indoor unit (Ic, Id).

[0138] Figure 3 is a control block diagram of an air conditioner according to the present embodiment.

[0139] The outdoor unit (O) may include a communication unit (130) and a control unit (140).

[0140] The communication unit (130) can communicate with the indoor unit (I). The communication unit (130) can transmit the mode (cooling mode or heating mode) of the indoor unit (I) to the control unit (140).

[0141] The control unit (140) can control the overall operation of the outdoor unit according to the signal transmitted from the communication unit (130).

[0142] The control unit (140) can control the compressor (1), the indoor fan (3), the first euro switching valve (4), the second euro switching valve (5), the third euro switching valve (6), the first opening control valve (7), the second opening control valve (8), and the outdoor expansion valve (25).

[0143] The control unit (140) can control the first euro switching valve (4), the second euro switching valve (5), and the third euro switching valve (6) according to the cooling and heating of the indoor unit (I).

[0144] The control unit (140) can control the first euro switching valve (4) to compressor supply mode or outdoor heat exchanger supply mode depending on the cooling and heating of the indoor unit (I).

[0145] The control unit (140) can turn the first euro switching valve (4) on and off according to the cooling and heating of the indoor unit (I).

[0146] The first euro changeover valve (4) can be in compressor supply mode when on and in outdoor heat exchanger supply mode when off.

[0147] The first euro switching valve (4) is turned on during heating and can guide the refrigerant flowing in from the connecting pipe (28) to the compressor suction pipe (11).

[0148] The first euro switching valve (4) is turned off during cooling, so that the refrigerant flowing in from the first branch pipe (17) can be guided to the connecting pipe (28).

[0149] The control unit (140) can control the second euro switching valve (5) to compressor supply mode or high-pressure engine supply mode depending on the cooling and heating of the first indoor unit (Ia, Ib).

[0150] The control unit (140) can turn the second euro switching valve (5) on and off according to the cooling and heating of the first indoor unit (Ia, Ib).

[0151] The second euro switching valve (5) can be in compressor supply mode when on and in high pressure engine supply mode when off.

[0152] The second euro switching valve (5) is turned on during cooling-only operation and can guide the refrigerant flowing in from the high-pressure engine (51) to the compressor suction pipe (11).

[0153] The second euro switching valve (5) is turned off during cooling-only operation, heating-only operation, and heating-only operation, and can guide the refrigerant flowing in from the compressor discharge pipe (16) to the high-pressure engine (61).

[0154] The control unit (140) can control the third euro switching valve (6) to compressor supply mode or low-pressure engine supply mode depending on the cooling and heating of the second indoor unit (Ic, Id).

[0155] The control unit (140) can turn the third euro switching valve (6) on and off according to the cooling and heating of the second indoor unit (Ic, Id).

[0156] The third euro switching valve (6) can be in compressor supply mode when on, and in low pressure engine supply mode when off.

[0157] The third euro switching valve (6) can be turned on during cooling-only operation, cooling-main operation, and heating-main operation, and can guide the refrigerant flowing in from the low-pressure engine (61) to the compressor suction pipe (11).

[0158] The third euro switching valve (6) is turned off during heating-only operation, so that the refrigerant flowing in from the compressor discharge pipe (16) can be guided to the low-pressure engine (61).

[0159] The control unit (140) can control at least one of the first opening control valve (7) and the second opening control valve (8) according to the set temperature of the first zone (Z1) and the set temperature of the second zone (Z2).

[0160] When the set temperature of the first zone (Z1) and the set temperature of the second zone (Z2) are the same, the control unit (140) can fully open both the first opening control valve (7) and the second opening control valve (8).

[0161] Figure 4 is a diagram illustrating the refrigerant flow when the air conditioner according to the present embodiment is in cooling-only operation.

[0162] When all indoor units (I) of the air conditioner are in cooling mode, the 1st, 2nd, and 3rd euro switching valves (4), (5), and (6) can be controlled to off / on / on, the outdoor heat exchanger (2) can function as a condenser, and the indoor heat exchangers (91) of all indoor units (I) can function as evaporators.

[0163] The high-pressure gas (2) discharged from the compressor (1) passes through the first flow-through valve (4) and flows into the outdoor heat exchanger (2), where it is condensed and distributed as high-pressure liquid refrigerant through the liquid pipe (21) to the first indoor unit (Ia, Ib) of the first zone (Z1) and the second indoor unit (Ic, Id) of the second zone (Z2).

[0164] The refrigerant introduced into the first indoor unit (Ia, Ib) is expanded by the indoor expansion valve (94) of the first indoor unit (Ia, Ib), evaporated by the indoor heat exchanger (91) of the first indoor unit (Ia, Ib), and returned to the outdoor unit (O) along the high-pressure pipe (51) as a low-pressure gaseous refrigerant, and at this time, passes through the first opening control valve (7). The refrigerant that has passed through the first opening control valve (7) is guided to the compressor suction pipe (11) by the second flow switching valve (5), flows into the accumulator (12a), and then circulates to the suction end of the compressor (1).

[0165] The refrigerant introduced into the second indoor unit (Ic, Id) is expanded by the indoor expansion valve (94) of the second indoor unit (Ic, Id), evaporated by the indoor heat exchanger (91) of the second indoor unit (Ic, Id), and returned to the outdoor unit (O) along the low-pressure pipe (61) as a low-pressure gaseous refrigerant, and at this time, passes through the second opening control valve (8). The refrigerant that has passed through the second opening control valve (8) is guided to the compressor suction pipe (11) by the third flow-through switching valve (6), flows into the accumulator (12a), and then circulates to the suction end of the compressor (1).

[0166] The first opening control valve (7) and the second opening control valve (8) are maintained in a full open state when there is no difference in the set temperature between zones (Z1, Z2).

[0167] On the other hand, when there is a difference in the set temperature between zones (Z1, Z2) or the indoor evaporation pressure is low and continuous operation is impossible, the first opening control valve (7) and the second opening control valve (8) individually control the evaporation pressure of the indoor unit for each zone (Z1, Z2) by controlling either the first opening control valve (7) or the second opening control valve (8).

[0168] Figure 4 is a diagram showing a case where the set temperature of the first zone (Z1) is set higher than that of the second zone (Z2).

[0169] In order to make the indoor temperature of the first zone (Z1) higher than the indoor temperature of the second zone (Z2), the opening of the first opening control valve (7) connected to the indoor unit (Ia, Ib) of the first zone (Z1) and the high pressure engine (51) can be reduced.

[0170] The air conditioner can generate a pressure loss due to the first opening control valve (7), and the air conditioner can be operated so that the evaporation pressure of the first indoor unit (Ia, Ib) is higher than the system evaporation pressure (P_low) and the evaporation pressure (P2) of the second indoor unit (Ic, Id) arranged in the second zone (Z2).

[0171] Here, the system evaporation pressure (P_low) may be the pressure of the refrigerant passing through the compressor suction pipe (11).

[0172] At this time, the second indoor unit (Ic, Id) placed in the second zone (Z2) and the second opening control valve (8) connected to the low pressure engine (61) are maintained in the fully open state, so that there is no need for pressure loss, and the air conditioner does not need to reduce the cycle efficiency. The air conditioner can make the evaporation pressure (P2) of the second indoor unit (Ic, Id) the same as the system evaporation pressure (P_low), and the air conditioner controls the system evaporation pressure through the compressor (1) to match the set temperature of the second zone (Z2).

[0173] Figure 5 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in heating-only operation.

[0174] When all indoor units (I) of the air conditioner are in heating mode, the 1st, 2nd, and 3rd euro switching valves (4), (5), and (6) are controlled to on / off / off, and the outdoor heat exchanger (2) can function as an evaporator, and the indoor heat exchangers (91) of all indoor units (I) can function as condensers.

[0175] The high-pressure gaseous refrigerant discharged from the compressor (1) can be distributed and guided to the second flow switching valve (5) and the second flow switching valve (5).

[0176] The high-pressure gaseous refrigerant guided to the second flow-through switching valve (5) passes through the first opening control valve (7), flows to the indoor heat exchanger (13) of the first indoor unit (Ia, Ib) and is condensed, flows to the outdoor unit (O), passes through the first branch liquid pipe (23) and the common liquid pipe (21), is expanded by the outdoor expansion valve (25), and is evaporated by the outdoor heat exchanger (2). The refrigerant evaporated by the outdoor heat exchanger (2) is guided to the compressor suction pipe (11) by the first flow-through switching valve (4), flows into the accumulator (12a), and is then circulated to the suction end of the compressor (1).

[0177] The high-pressure gas refrigerant guided to the third flow-change valve (6) passes through the second opening control valve (8), flows to the indoor heat exchanger (13) of the second indoor unit (Ic, Id) and is condensed, flows to the outdoor unit (O), passes through the second branch liquid pipe (24) and the common liquid pipe (21), is expanded by the outdoor expansion valve (25), and is evaporated by the outdoor heat exchanger (2). The refrigerant evaporated by the outdoor heat exchanger (2) is guided to the compressor suction pipe (11) by the first flow-change valve (4), flows into the accumulator (12a), and is then circulated to the suction end of the compressor (1).

[0178] At this time, the first opening control valve (7) and the second opening control valve (8) can be maintained in full open (Full OPEN) state, and unnecessary pressure loss does not occur.

[0179] Figure 6 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in cooling operation.

[0180] When the cooling main unit is in operation, the first euro switching valve (4) can be turned off and the outdoor heat exchanger (2) can function as a condenser.

[0181] The euro switching valve connected to the indoor heat exchanger (13) of the indoor unit in heating mode can be turned off, and the indoor heat exchanger (13) of the indoor unit in heating mode can function as a condenser.

[0182] The euro switching valve connected to the indoor heat exchanger (13) of the indoor unit in cooling mode can be turned on, and the indoor heat exchanger (13) of the indoor unit in cooling mode can function as an evaporator.

[0183] The high-pressure gas refrigerant discharged from the compressor (1) can be distributed and guided to the first flow-change valve (4) and the flow-change valve (e.g., the second flow-change valve (5)) connected to the indoor unit in heating mode.

[0184] The refrigerant guided to the first euro changeover valve (4) can be condensed by the outdoor heat exchanger (2) and then guided to the common liquid pipe (22).

[0185] The refrigerant guided to the refrigerant changeover valve (e.g., the second refrigerant changeover valve (5)) connected to the indoor unit in heating mode and the engine passes through the opening control valve (e.g., the first opening control valve (7)) corresponding to the indoor unit in heating mode, and is then condensed by the indoor heat exchanger (13) of the indoor unit in heating mode, and can be guided to the branch liquid pipe (e.g., the first branch liquid pipe (23)) connected to the indoor unit in heating mode.

[0186] The refrigerant guided to the common liquid pipe (22) and the refrigerant guided to the branch liquid pipe (e.g., the first branch liquid pipe (23)) connected to the indoor unit in heating mode can be combined in the branch liquid pipe (e.g., the second branch liquid pipe (24)) connected to the indoor unit in cooling mode, and the refrigerant in a high-pressure liquid state can be moved to the indoor unit in cooling mode.

[0187] The refrigerant can be expanded by the electronic expansion valve (14) of the indoor unit in cooling mode and evaporated by the indoor heat exchanger (91) of the indoor unit in cooling mode.

[0188] The low-pressure gas refrigerant evaporated by the indoor heat exchanger (91) of the indoor unit in cooling mode can be introduced into the outdoor unit (O) by being guided to a device (e.g., a low-pressure device (61)) connected to the indoor unit in cooling mode.

[0189] The refrigerant introduced into the outdoor unit (O) passes through an opening control valve (e.g., a second opening control valve (8)) connected to an indoor unit in cooling mode, and is then guided to the compressor suction pipe (11) by a flow switching valve (e.g., a third flow switching valve (6)) connected to the indoor unit in cooling mode, and then flows into an accumulator (12a) and is circulated to the suction end of the compressor (1).

[0190] At this time, the first opening control valve (7) and the second opening control valve (8) can be maintained in a fully open state, and there is no reduction in efficiency due to pressure loss.

[0191] However, in a situation where the indoor set temperature is high and the indoor evaporation pressure must be increased, if the overall system evaporation pressure cannot be increased considering the compressor reliability, product operating area, and indoor heating unit performance, the opening control valve (e.g., the second opening control valve (8)) connected to the indoor unit in cooling mode can be controlled (i.e., decreased), and the indoor evaporation pressure can be increased.

[0192] Figure 6 is a diagram showing when the first indoor unit (Ia, Ib) of the first zone (Z1) is in heating mode, the second indoor unit (Ic, Id) of the second zone (Z2) is in cooling mode, and the outdoor heat exchanger (2) functions as a condenser.

[0193] The indoor heat exchanger (13) placed in the first indoor unit (Ia, Ib) placed in the first zone (Z1) functions as a condenser, the indoor heat exchanger (13) placed in the second indoor unit (Ic, Id) placed in the second zone (Z2) functions as an evaporator, and the outdoor heat exchanger (2) functions as a condenser. In order for this, the first, second, and third flow changeover valves (4)(5)(6) can be controlled to off / off / on.

[0194] If the first indoor unit (Ia, Ib) of the first zone (Z1) is in cooling mode and the second indoor unit (Ic, Id) of the second zone (Z2) is in heating mode, the first, second, and third euro switching valves (4)(5)(6) can be controlled to off / on / off.

[0195] Both the first opening control valve (7) and the second opening control valve (8) can be maintained in the full open state, and the high / low pressure of the system can be transmitted to the indoor unit side as is.

[0196] Fig. 7 is a diagram showing the refrigerant flow when the air conditioner according to the present embodiment is in heating-main operation.

[0197] When the heating main unit is in operation, the first euro changeover valve (4) can be turned on and the outdoor heat exchanger (2) can function as an evaporator.

[0198] The euro switching valve connected to the indoor heat exchanger (13) of the indoor unit in heating mode can be turned off, and the indoor heat exchanger (13) of the indoor unit in heating mode can function as a condenser.

[0199] The euro switching valve connected to the indoor heat exchanger (13) of the indoor unit in cooling mode can be turned on, and the indoor heat exchanger (13) of the indoor unit in cooling mode can function as an evaporator.

[0200] The high-pressure gas refrigerant discharged from the compressor (1) can be guided to a flow-change valve (e.g., a second flow-change valve (5)) connected to an indoor unit in heating mode.

[0201] The refrigerant guided to the refrigerant changeover valve (e.g., the second refrigerant changeover valve (5)) connected to the indoor unit in heating mode and the engine passes through the opening control valve (e.g., the first opening control valve (7)) corresponding to the indoor unit in heating mode, and is then condensed by the indoor heat exchanger (13) of the indoor unit in heating mode, and can be guided to the branch liquid pipe (e.g., the first branch liquid pipe (23)) connected to the indoor unit in heating mode.

[0202] The refrigerant guided to the branch liquid pipe (e.g., the first branch liquid pipe (23)) connected to the indoor unit in heating mode can be guided to the branch liquid pipe (e.g., the second branch liquid pipe (24)) connected to the indoor unit in cooling mode and the common liquid pipe (22), and can be distributed to the indoor unit and outdoor unit (O) in cooling mode.

[0203] The refrigerant guided to the branch liquid pipe (e.g., the second branch liquid pipe (24)) connected to the indoor unit in cooling mode can be expanded by the electronic expansion valve (14) of the indoor unit in cooling mode and evaporated by the indoor heat exchanger (91) of the indoor unit in cooling mode.

[0204] The low-pressure gas refrigerant can be introduced into the outdoor unit (O) by the indoor heat exchanger (91) of the indoor unit in cooling mode through a duct (e.g., a low-pressure duct (61)) connected to the indoor unit in cooling mode. The refrigerant introduced into the outdoor unit (O) can pass through an opening control valve (e.g., a second opening control valve (8)) connected to the duct of the indoor unit in cooling mode, and then be guided to the compressor suction pipe (11) by a flow switching valve (e.g., a third flow switching valve (6)) connected to the indoor unit in cooling mode.

[0205] The refrigerant guided to the common pipe (22) can be expanded by the outdoor expansion valve (25), evaporated by the outdoor heat exchanger (2), and then guided to the first flow switching valve (4). The first flow switching valve (4) guides the refrigerant to the compressor suction pipe (11), where it can be combined with the refrigerant guided by the flow switching valve connected to the indoor unit in cooling mode.

[0206] The refrigerant in the compressor suction pipe (11) flows into the accumulator (12a) and then circulates to the suction end of the compressor (1).

[0207] At this time, the opening control valve corresponding to the indoor unit of the heater (the first opening control valve (7)) can be maintained in full open (Full OPEN) and there is no decrease in efficiency due to pressure loss.

[0208] Meanwhile, the opening control valve corresponding to the indoor unit for heating (second opening control valve (8)) is fully open (Full OPEN) when there is no risk of dew or freezing in the indoor heat exchanger (94) of the indoor unit for cooling, and when there is a risk of dew or freezing, it operates through opening control (i.e., reduction control) so that the evaporation pressure of the indoor heat exchanger (94) of the indoor unit for cooling is higher than the system evaporation pressure.

[0209] Figure 7 is a diagram showing when the first indoor unit (Ia, Ib) of the first zone (Z1) is in heating mode, the second indoor unit (Ic, Id) of the second zone (Z2) is in cooling mode, and the outdoor heat exchanger (2) functions as an evaporator.

[0210] The indoor heat exchanger (13) placed in the first indoor unit (Ia, Ib) placed in the first zone (Z1) functions as a condenser, the indoor heat exchanger (13) placed in the second indoor unit (Ic, Id) placed in the second zone (Z2) functions as an evaporator, and the outdoor heat exchanger (2) functions as an evaporator. In order for the first, second, and third flow changeover valves (4), (5), and (6) to be controlled to on / off / on.

[0211] If the first indoor unit (Ia, Ib) of the first zone (Z1) is in cooling mode and the second indoor unit (Ic, Id) of the second zone (Z2) is in heating mode, the first, second, and third euro changeover valves (4)(5)(6) can be controlled to on / on / off.

[0212] Both the first opening control valve (7) and the second opening control valve (8) can be maintained in the full open state, and the high / low pressure of the system can be transmitted to the indoor unit side as is.

[0213] In particular, the opening control valve corresponding to the indoor unit in cooling mode can be fully open (Full OPEN) if there is no concern about dew or freezing.

[0214] However, if the set temperature of the indoor unit in cooling mode is high and the evaporation pressure of the indoor unit in cooling mode must be increased, but the evaporation pressure of the entire system cannot be increased considering the compressor reliability, product operating area, and performance of the heating indoor unit, the evaporation pressure of the indoor unit in cooling mode can be increased by controlling the opening (i.e., decreasing control) of the opening control valve corresponding to the indoor unit in cooling mode.

[0215] In addition, when there is concern about excessive condensation due to dew formation on the indoor heat exchanger of the indoor unit in cooling mode or reduced heat exchange efficiency due to freezing of the heat exchanger due to low outside temperature or high indoor humidity, the opening control valve corresponding to the indoor unit in cooling mode can be reduced (i.e., reduced control) to increase the evaporation pressure of the indoor unit in cooling mode, thereby preventing excessive condensation or reduced heat exchange efficiency.

[0216] Figure 8 is a flowchart illustrating a method of operating an air conditioner according to the present embodiment.

[0217] If the operation mode of each of the first indoor unit (Ia, Ib) and the second indoor unit (Ic, Id) is the heating mode, the first opening control valve (7) and the second opening control valve (8) can be fully open.

[0218] If the difference between the set temperature of the first indoor unit (Ia, Ib) and the set temperature of the second indoor unit (Ic, Id) is less than the set value, the first opening control valve (7) and the second opening control valve (8) can be fully open.

[0219] If the outside temperature is higher than the set outside temperature, the first opening control valve (7) and the second opening control valve (8) can be fully open.

[0220] If the operation mode of the first indoor unit (Ia, Ib) and the second indoor unit (Ic, Id) is the cooling mode, and the difference between the set temperature of the first indoor unit (Ia, Ib) and the set temperature of the second indoor unit (Ic, Id) is greater than or equal to a set value (e.g., 0.5°C or 1°C), the opening degree of the opening degree control valve corresponding to the indoor unit with the higher set temperature among the first opening degree control valve and the second opening degree control valve can be reduced.

[0221] When the operation mode of the first indoor unit (Ia, Ib) and the second indoor unit (Ic, Id) is the cooling mode and the outside temperature is lower than the set temperature, at least one of the first opening control valve and the second opening control valve can be adjusted to control the flow rate.

[0222] The method of controlling an air conditioner is such that when the air conditioner system starts operating, the control unit (140) can keep the first opening control valve (7) and the second opening control valve (8) fully open (S1, S2).

[0223] If a cooling zone exists among the zones where the first indoor unit is placed and the zones where the second indoor unit is placed, the control unit (140) can perform a process (first process) of calculating the representative set temperature (Tset) for each zone, the current dew point temperature (Tdew), and the current pipe inlet temperature (Ti) (S3, S4).

[0224] The representative set temperature (Tset), current dew point temperature (Tdew), and current pipe inlet temperature (Ti) can only be calculated for indoor units that are thermo-on within the zone.

[0225] The representative set temperature (Tset), current dew point temperature (Tdew), and current pipe inlet temperature (Ti) of indoor units placed within the same zone can each be calculated as a capacity-weighted average.

[0226] The current dew point temperature (Tdew) can be calculated by an indoor temperature and humidity sensor (not shown).

[0227] The current pipe inlet temperature (Ti) can be calculated by a temperature sensor (not shown) placed in the inlet pipe (first pipe (93) or second pipe (95)) of the indoor heat exchanger of the indoor unit of the cooling system.

[0228] The control unit (140) can perform a process (second process) of calculating a target pipe inlet temperature (Target Ti) for each zone if all zones are cooling and the cooling set temperatures (Tset) of the zones are different (S5, S6, S7).

[0229] Checking that all zones are cooled may mean checking the driving mode only for the zones that are being driven.

[0230] The above process (second process) can calculate the first target pipe inlet temperature (Target Ti) of the first cooling zone and the second target pipe inlet temperature (Target Ti) of the second cooling zone.

[0231] The calculation of the target pipe inlet temperature is described later.

[0232] The control unit (140) can perform a process (third process) of controlling the opening control valve corresponding to the zone of the highest target pipe inlet temperature among the target pipe inlet temperatures (Target Ti) calculated for each zone to track the pipe inlet temperature (S8, S9).

[0233] The control unit (140) can control the first opening control valve (7) corresponding to the first zone (Z1) to follow the first target pipe inlet temperature (Target Ti 1) when the first target pipe inlet temperature (Target Ti 1) is the highest among the first target pipe inlet temperature (Target Ti 1) and the second target pipe inlet temperature (Target Ti 2).

[0234] The control unit (140) can control the second opening control valve (8) corresponding to the second zone (Z2) to follow the second target pipe inlet temperature (Target Ti 2) when the second target pipe inlet temperature (Target Ti 2) is the highest among the first target pipe inlet temperature (Target Ti 1) and the second target pipe inlet temperature (Target Ti 2).

[0235] If the control unit (140) is not a cooling zone and the current pipe inlet temperature (Ti) is lower than the current dew point temperature (Tdew) or freezing temperature (Tfreeze), the control unit (140) can perform a process (step 4) of setting the target pipe inlet temperature (Target Ti) of the cooling zone to a set temperature (e.g., 2°C) higher than the current dew point temperature (S10, S11). In addition, the opening control valve can be controlled to follow the pipe inlet temperature (S9).

[0236] The control unit (140) can perform a process (5th process) of changing the system target evaporation pressure.

[0237] The control unit (140) can change the system target evaporation pressure according to the target pipe inlet temperature (Target Ti) of a zone that is not the highest among the target pipe inlet temperatures (Target Ti) calculated for each zone (S8, S12).

[0238] The control unit (140) can change the system target evaporation pressure according to the second target pipe inlet temperature (Target Ti 2) when the first target pipe inlet temperature (Target Ti) is the highest among the first target pipe inlet temperature (Target Ti 1) and the second target pipe inlet temperature (Target Ti 2).

[0239] The control unit (140) can change the system target evaporation pressure according to the first target pipe inlet temperature (Target Ti 1) when the second target pipe inlet temperature (Target T2) is the highest among the first target pipe inlet temperature (Target Ti 1) and the second target pipe inlet temperature (Target Ti 2).

[0240] The control unit (140) can change the system target evaporation pressure according to the current pipe inlet temperature if not all zones are refrigerated and the current pipe inlet temperature (Ti) is higher than the current dew point temperature (Tdew) or freezing temperature (Tfreeze) (S5, S10, S11, S12).

[0241] The control unit (140) can change the system target evaporation pressure according to the current pipe inlet temperature (Ti) if the cooling set temperature (Tset) of the zones is the same (S6, S12).

[0242] Below, the calculation of the target pipe inlet temperature is explained.

[0243] When multi-evaporation pressure control is required due to different set temperatures of zones (Z1, Z2) or concerns about freezing of the indoor heat exchanger of the air-conditioning indoor unit, the first opening control valve (7) and the second opening control valve (8) can control the evaporation pressure of the air-conditioning indoor unit by tracking control for the target pipe inlet temperature suitable for the operating conditions.

[0244] Fig. 9 is a diagram showing the target pipe inlet temperature according to the set temperature when the set temperatures of the zones according to the present embodiment are different.

[0245] In order to set the set temperature of the indoor unit (I), it is desirable to directly sense and control the temperature taken out from the indoor unit (I), but the indoor unit (I) may not include an exhaust temperature sensor that senses the temperature of the air taken out, and the deviation in the exhaust temperature may be large depending on the location of the discharge port of the indoor unit (I).

[0246] When using the sensing value of the pipe inlet temperature sensor of the indoor unit, the first opening control valve (7) and the second opening control valve (8) can be controlled, and in terms of improving the reliability of the air conditioner, it is preferable to control the first opening control valve (7) and the second opening control valve (8) using the sensing value of the pipe inlet temperature sensor of the indoor unit.

[0247] The pipe inlet temperature sensor of the indoor unit can be placed at the rear end of the indoor expansion valve (94) based on cooling, and since it is a two-phase refrigerant temperature, the pipe inlet temperature can represent the individual saturation temperature (cooling standard, evaporation temperature) on the indoor unit side.

[0248] Therefore, the correlation between the discharge temperature of the indoor unit (I) and the pipe inlet temperature can be experimentally confirmed through experiments, and based on this, the target pipe inlet temperature for implementing the discharge temperature suitable for the set temperature can be calculated. However, even if the set temperature is low, the pipe inlet temperature can be calculated so that it is at least higher than the dew point temperature or freezing temperature.

[0249] The target pipe inlet temperature of the first zone (Z1) (i.e., the first target pipe inlet temperature) can be calculated by an equation (e.g., Target Ti 1 = f(Tset 1, Tdew 1, Tfreeze 1)) that uses the set temperature of the first zone, the dew point temperature of the first zone, and the freezing temperature of the first zone as factors.

[0250] The target pipe inlet temperature of the second zone (Z2) (i.e., the second target pipe inlet temperature) can be calculated by an equation (e.g., Target Ti 2 = f(Tset 2, Tdew 2, Tfreeze 2)) that uses the set temperature of the second zone, the dew point temperature of the second zone, and the freezing temperature of the second zone as factors.

[0251] When multiple indoor units exist in one zone, there may be differences in the set temperatures between indoor units in the same zone. First, since indoor units in the same zone are connected to a single opening control valve, it may be difficult to control the individual pipe inlet temperatures in the same zone.

[0252] If there is a difference in the set temperature between indoor units in the same zone, a representative set temperature can be derived as a weighted average of the capacities of indoor units in the same zone, and the opening control valve can be controlled according to the representative set temperature.

[0253] In addition, the entire system evaporation pressure can be controlled by the compressor (1) based on the lowest temperature among the zone-specific set temperatures, and the opening control valve of the corresponding zone can be fully opened (Full OPEN) to minimize the decrease in system efficiency due to the opening control valve.

[0254] In addition to multi-evaporation pressure control due to differences in the set temperatures between zones, if the system evaporation pressure is low due to low outside temperature, compressor operating area, etc., and there is a concern about condensation and freezing on the indoor unit side, the target pipe inlet temperature can be changed to be higher than the dew point temperature and freezing temperature derived using the indoor unit side temperature / humidity sensor, and the first opening control valve (7) and the second opening control valve (8) can be controlled accordingly to avoid this.

[0255] When the pipe inlet temperature is derived, the first opening control valve (7) and the second opening control valve (8) can perform control to follow the pipe inlet temperature according to a built-in fuzzy control table.

[0256] The above description is merely an example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention.

[0257] Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention but to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments.

[0258] The scope of protection of the present invention should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A compressor with a compressor suction pipe and a compressor discharge pipe connected; Outdoor heat exchanger with connected liquid and connecting pipes; A first directional valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the connecting pipe; A second directional control valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the high pressure engine; A third flow-through switching valve connected to each of the compressor suction pipe, the compressor discharge pipe, and the low-pressure engine; An outdoor expansion valve installed in the above liquid pipe; A first indoor unit connected to the above liquid pipe and high pressure engine; A second indoor unit connected to the above liquid pipe and low pressure organ; A first opening control valve arranged in the above high pressure engine; and Including a second opening control valve arranged in the above low pressure engine, An air conditioner in which the first opening control valve and the second opening control valve are controlled according to the operation mode and set temperature of the first indoor unit and the second indoor unit, respectively.

2. In paragraph 1, The above compressor suction pipe Common suction pipe with accumulator placed; A first joint pipe connected to the above common suction pipe and the first euro switching valve; A second joint pipe connected to the above common suction pipe and the second euro switching valve; and An air conditioner including a third joint pipe connected to the common suction pipe and the third euro switching valve.

3. In paragraph 1, The above compressor discharge pipe Common discharge pipe with oil separator arranged; A first branch pipe connected to the first euro switching valve; A second branch pipe connected to the above common discharge pipe and the second euro switching valve; and An air conditioner comprising a third branch pipe connected to the common discharge pipe and the third euro switching valve.

4. In paragraph 3, An air conditioner in which one end of the first branch pipe is connected to the third branch pipe, and the other end of the first branch pipe is connected to the first flow switching valve.

5. In paragraph 1, The above liquid pipe Common liquid line with outdoor expansion valve; A first branch pipe connected to each of the above common pipe and the first indoor unit; and An air conditioner including a second branch liquid pipe connected to each of the common liquid pipe and the second indoor unit.

6. In paragraph 1, An air conditioner in which the first opening control valve and the second opening control valve are electronic expansion valves.

7. In paragraph 1, An air conditioner further comprising a control unit that controls the compressor, the first euro switching valve, the second euro switching valve, the third euro switching valve, the first opening control valve, and the second opening control valve.

8. In paragraph 7, If the operation mode of each of the first indoor unit and the second indoor unit is heating mode, An air conditioner in which the first opening control valve and the second opening control valve are fully open.

9. In paragraph 7, If the difference between the set temperature of the first indoor unit and the set temperature of the second indoor unit is less than the set value, An air conditioner in which the first opening control valve and the second opening control valve are fully open.

10. In paragraph 7, If the outside temperature is higher than the set outside temperature, An air conditioner in which the first opening control valve and the second opening control valve are fully open.

11. In paragraph 7, If the operation mode of each of the first indoor unit and the second indoor unit is the cooling mode, and the difference between the set temperature of the first indoor unit and the set temperature of the second indoor unit is greater than the set value, An air conditioner that reduces the opening degree of an opening degree control valve corresponding to an indoor unit having a high set temperature among the first opening degree control valve and the second opening degree control valve.

12. In paragraph 7, If the operation mode of each of the first indoor unit and the second indoor unit is cooling mode and the outside temperature is below the set temperature, An air conditioner in which at least one of the first opening control valve and the second opening control valve controls the flow rate by adjusting the opening degree.

13. In paragraph 7, The above control unit If there is a cooling zone among the zones where the first indoor unit is placed and the zones where the second indoor unit is placed, the first process of calculating the representative set temperature for each zone, the current dew point temperature, and the current pipe inlet temperature; If all zones are cooling and the cooling setpoints of the zones are different, the second step is to calculate the target pipe inlet temperature for each zone; and An air conditioner that performs a third process of controlling the opening control valve corresponding to the zone of the highest target pipe inlet temperature among the target pipe inlet temperatures calculated for each zone, by following the pipe inlet temperature.

14. In paragraph 13, The above control unit An air conditioner that performs a fourth step of setting the target pipe inlet temperature of a cooling zone to a set temperature higher than the current dew point temperature when the current pipe inlet temperature is lower than the current dew point temperature or freezing temperature, if not all zones are cooling zones.

15. In paragraph 14, The above control unit An air conditioner that changes the system target evaporation pressure according to the target pipe inlet temperature of a zone that is not the highest among the target pipe inlet temperatures calculated for each zone, or, if no zone is for cooling and the current pipe inlet temperature is higher than the current dew point temperature or freezing temperature, performs a fifth step of changing the system target evaporation pressure according to the current pipe inlet temperature.

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