KR102494571B1 - Heat pump - Google Patents

Abstract

The present invention includes a compression unit having a compressor and a cooling/heating switching valve; an outdoor heat exchanger connected to the compression unit by a connection line between the outdoor heat exchanger and having a main flow path and a sub flow path; an indoor heat exchanger connected to the compression unit by a connection line between the indoor heat exchanger and the indoor heat exchanger; an outdoor expansion mechanism connected to the main flow path through a first expansion mechanism connection line; an indoor expansion device connected to the indoor heat exchanger by a connection line to the second expansion device and connected to the outdoor expansion device by a connection line to the third expansion device; a first bypass line for guiding the refrigerant compressed in the compression unit to the sub-passage; a second bypass line for guiding the refrigerant passing through the sub-passage to the first expansion mechanism connection line; a flow control valve installed in the first bypass line or the second bypass line; a bypass temperature sensor for sensing the temperature of the second bypass line; an outdoor temperature sensor; a humidity sensor; During heating operation, the outdoor temperature that controls the opening of the flow control valve is controlled according to the dew point temperature calculated by the outdoor temperature detected by the outdoor temperature sensor and the outdoor humidity detected by the humidity sensor, and the bypass outlet temperature detected by the bypass temperature sensor during heating operation. It includes a control unit that implements an anti-icing mode in the heat exchanger, wherein the control unit controls the outdoor temperature during the heating operation to be higher than the outdoor set temperature, the current high pressure to be greater than the sum of the first set pressure and the target high pressure while the compressor is driven at the minimum frequency. or equal, the heating low load mode is executed, and the control unit increases the opening degree of the flow control valve when the current high pressure is greater than the sum of the target high pressure and the second set pressure higher than the first set pressure in the heating low load mode By increasing the opening degree, there is an advantage in that the temperature of the outdoor heat exchanger can be quickly managed within a temperature range in which icing does not occur while minimizing a decrease in heating efficiency.

Description

Heat pump {Heat pump}

The present invention relates to a heat pump, and more particularly, to a heat pump in which a sub-passage formed in an outdoor heat exchanger can bypass a refrigerant.

A heat pump is a cooling and heating device that transfers a low-temperature heat source to a high temperature or a high-temperature heat source to a low temperature by using heat or condensation heat of a refrigerant.

The heat pump includes a compressor that compresses the refrigerant, a cooling/heating switching valve that switches between cooling and heating operation by changing the flow direction of the refrigerant, an outdoor heat exchanger that exchanges heat between the refrigerant and outdoor air, an expansion mechanism that expands the refrigerant, and a refrigerant. The indoor air can be cooled or heated using a refrigeration cycle including an indoor heat exchanger that exchanges heat with indoor air.

The outdoor heat exchanger of the heat pump may function as an evaporator for exchanging heat between the refrigerant and outdoor air during the heating operation, and frost may form on the outdoor heat exchanger during the heating operation of the heat pump.

KR 10-2009-0129195 A (published on December 16, 2009) KR 10-2011-0019219 A (published on February 24, 2011)

An object of the present invention is to provide a heat pump capable of continuing heating operation while minimizing the occurrence of icing in an outdoor heat exchanger.

Another object of the present invention is to provide a heat pump capable of minimizing power consumption and minimizing frequent on/off of a compressor when an indoor heat exchanger is overheated at a heating low load.

A heat pump according to an embodiment of the present invention includes a compression unit having a compressor and a cooling/heating switching valve; an outdoor heat exchanger connected to the compression unit through a connection line between the outdoor heat exchanger and having a main flow path and a sub flow path; an indoor heat exchanger connected to the compression unit through a connection line between the indoor heat exchanger and the indoor heat exchanger; an outdoor expansion mechanism connected to the main flow path through a first expansion mechanism connection line; an indoor expansion device connected to the indoor heat exchanger through a connection line to the second expansion device and connected to the outdoor expansion device through a connection line to the third expansion device; a first bypass line for guiding the refrigerant compressed in the compression unit to the sub-passage; a second bypass line for guiding the refrigerant passing through the sub-passage to the first expansion mechanism connection line; a flow control valve installed in the first bypass line or the second bypass line; a bypass temperature sensor for sensing the temperature of the second bypass line or sub-passage; an outdoor temperature sensor for sensing outdoor temperature; a humidity sensor for detecting outdoor humidity; During the heating operation, the flow control valve operates according to the dew point temperature calculated by the outdoor temperature detected by the outdoor temperature sensor and the outdoor humidity detected by the humidity sensor, and the bypass outlet temperature detected by the bypass temperature sensor. It includes a control unit that performs an anti-icing mode of the outdoor heat exchanger to control the opening degree, wherein the control unit controls the outdoor temperature during heating operation to be higher than the outdoor set temperature, and the current high pressure is the first set pressure and the target while the compressor is driven at the minimum frequency. If it is greater than or equal to the sum of the high pressures, the heating low load mode is performed, and the control unit operates the flow control valve when the current high pressure is greater than the sum of the target high pressure and the second set pressure higher than the first set pressure in the heating low load mode. The opening degree of can be increased by the set incremental opening degree.

The control unit may execute the outdoor heat exchanger anti-icing mode when the outdoor temperature is equal to or less than the first set temperature, the evaporation temperature is less than the second set temperature, and the dew point temperature is equal to or greater than the bypass outlet temperature.

The control unit may increase the opening of the flow control valve by a first set opening when the bypass outlet temperature is equal to or less than the dew point temperature in the outdoor heat exchanger in the anti-icing mode.

The control unit may decrease the opening of the flow control valve by a second set opening when the bypass outlet temperature is greater than the sum of the dew point temperature and the third set temperature in the outdoor heat exchanger anti-icing mode.

The control unit may maintain the opening degree of the flow control valve when the bypass outlet temperature is less than the sum of the dew point temperature and the third set temperature and greater than the dew point temperature in the outdoor heat exchanger anti-icing mode.

The control unit controls a fourth set temperature when the heat pump is in operation other than the heating operation, when the outdoor temperature exceeds the first set temperature, or when the flow control valve is at least open and the bypass outlet temperature is higher than the dew point temperature and the third set temperature. If it is greater than the sum of , the outdoor heat exchanger anti-icing mode can be released.

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The control unit controls the flow control valve to an initial reference opening degree when the heating low load mode is started, and increases or decreases the opening degree of the flow control valve when an initial set time elapses after controlling the flow control valve to an initial reference opening degree. .

The control unit may decrease the opening degree of the flow control valve by a set reduction degree when the current high pressure is less than the sum of the first set pressure and the target high pressure in the heating low load mode.

The setting reduction degree may be greater than the setting increasing opening degree.

The control unit may maintain the opening of the flow control valve when the current high pressure is less than or equal to the sum of the second set pressure and the target high pressure and greater than or equal to the sum of the first set pressure and the target high pressure in the heating low load mode.

The heating low load mode may be released when the heat pump is in operation other than the heating operation, the outdoor temperature is less than the outdoor set temperature, or the flow control valve is at the minimum opening degree and the compressor is in operation exceeding the minimum frequency.

According to an embodiment of the present invention, the opening degree of the flow control valve is controlled according to the change in the bypass outlet temperature, so that the temperature of the outdoor heat exchanger is quickly managed within a temperature range in which icing does not occur while minimizing the deterioration in heating efficiency. There are benefits you can do.

In addition, there is an advantage in that the heat pump can be continuously operated while minimizing power consumption without stopping the heat pump at a low load during the heating operation.

Further, since the refrigerant passing through the second bypass line flows into the main flow path without passing through the outdoor expansion mechanism, the refrigerant passing through the second bypass line flows into the main flow path after passing through the outdoor expansion mechanism. It has the advantage of minimizing resistance.

1 is a diagram illustrating a refrigerant flow during a heating operation of a heat pump according to an embodiment of the present invention;
2 is a diagram illustrating a refrigerant flow during a defrosting operation of a heat pump according to an embodiment of the present invention;
3 is a control block diagram of a heat pump according to an embodiment of the present invention;
4 is a diagram showing the flow of refrigerant in an anti-icing mode of an outdoor heat exchanger of a heat pump according to an embodiment of the present invention;
5 is a flowchart illustrating an anti-icing mode of an outdoor heat exchanger of a heat pump according to an embodiment of the present invention;
6 is a diagram illustrating a refrigerant flow in a heating low load mode of a heat pump according to an embodiment of the present invention;
7 is a flowchart illustrating a heating low load mode of a heat pump according to an embodiment of the present invention.

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

1 is a diagram showing the flow of refrigerant during a heating operation of a heat pump according to an embodiment of the present invention, FIG. 2 is a diagram showing the flow of refrigerant during a defrosting operation of a heat pump according to an embodiment of the present invention, and FIG. It is a control block diagram of a heat pump according to an embodiment of the invention.

The heat pump includes a compression unit 3 having a compressor 1 and a cooling/heating switching valve 2; an outdoor heat exchanger (10) connected by a compression unit (3) and an outdoor heat exchanger connection line (11) and having a main flow path (12) and a sub flow path (13); an indoor heat exchanger (20) connected to the compression unit (3) through an indoor heat exchanger connection line (21); an outdoor expansion mechanism (30) connected to the main flow path (12) through a first expansion mechanism connection line (31); An indoor expansion device 40 connected to the indoor heat exchanger 20 through a connection line 41 to the second expansion device and connected to the outdoor expansion device 30 through a connection line 42 to the third expansion device may be included.

The compressor 1 may be configured as an inverter compressor, and the input frequency may vary according to the load of the indoor heat exchanger 20 .

The compression unit 3 may further include an accumulator 4 installed in the suction line 1A of the compressor 1 and containing the liquid refrigerant. The accumulator 4 may be connected to the air conditioning/heating switching valve 2 through an accumulator suction line 4A.

The compression unit 3 may further include an oil separator 5 installed in the discharge line 1B of the compressor 1 to separate oil from the refrigerant discharged from the compressor 1 and guide it to the compressor suction line 1A. can The oil separator 5 may be connected to the air conditioning/heating switching valve 2 through the oil separator outlet line 5A.

The heat pump may include a high pressure sensor 6 installed in a high pressure unit. The high-pressure sensor 6 is installed in the discharge line 1B of the compressor 1 or the outlet line 5A of the oil separator to detect the pressure of the high-temperature and high-pressure refrigerant discharged from the compressor 1.

The heat pump may further include a low pressure sensor 7 installed in the low pressure unit. The low pressure sensor 7 is installed in the suction line 1A of the compressor 1 or the suction line 4A of the accumulator to detect the pressure of the refrigerant sucked into the compressor 1 from the heating/cooling switching valve 2. .

The outdoor heat exchanger 10 may include a main tube forming the main flow path 12, a sub tube forming the sub flow path 13, and heat transfer fins 14 connected to the main tube and the sub tube. The sub tube in which the sub flow path 13 is formed may be connected to the heat transfer fin 14 so as to be located below the main tube forming the main flow path 12 . The refrigerant passing through the main flow path 12 and the refrigerant passing through the sub flow path 13 do not mix with each other while passing through the outdoor heat exchanger 10, and can transfer heat through the heat transfer fins 14.

One end of the connection line 11 for the outdoor heat exchanger may be connected to the main flow path 12 and the other end may be connected to the air conditioning/heating switching valve 2 .

One end of the main flow passage 12 may be connected to the outdoor heat exchanger connection line 11 and the other end may be connected to the first expansion mechanism connection line 31 .

The sub flow path 13 may be connected to a first bypass line 50 and a second bypass line 60 to be described later. The sub flow path 13 may be located between the first bypass line 50 and the second bypass line 60 . The sub-passage 13 bypasses the indoor heat exchanger 20, the indoor expansion mechanism 40, and the indoor expansion mechanism 30 together with the first bypass line 50 and the second bypass line 60 for refrigerant. It may be a bypass flow path that guides pass.

The heat pump may further include an outdoor fan (not shown) for blowing outdoor air to the outdoor heat exchanger 10 .

The outdoor heat exchanger (10) is an evaporator in which the low-temperature, low-pressure refrigerant flowing from the outdoor expansion device (30) through the first expansion device connection line (31) passes through the main flow path (12) during cooling operation and exchanges heat with outdoor air. can

In the outdoor heat exchanger (10), during heating operation, the high-temperature, high-pressure refrigerant, which is compressed by the compressor (1) and then flows through the cooling/heating switching valve (2) and the outdoor heat exchanger connection line (11), passes through the main flow path (12). It may be a condenser that exchanges heat with outdoor air.

The heat pump may further include an indoor fan (not shown) for blowing indoor air to the indoor heat exchanger 20 .

One end of the indoor heat exchanger connection line 21 may be connected to the indoor heat exchanger 20 and the other end may be connected to the air conditioning/heating switching valve 2 .

The indoor heat exchanger 20 may be an evaporator in which the low-temperature, low-pressure refrigerant flowing through the second expansion device connection line 41 is evaporated through heat exchange with indoor air during a cooling operation. In the indoor heat exchanger (20), during heating operation, the high-temperature, high-pressure refrigerant that is compressed by the compressor (1) and then flowed through the cooling/heating switching valve (2) and the indoor heat exchanger connection line (21) is condensed by heat exchange with indoor air. It may be a condenser.

The first expansion mechanism 30 and the second expansion mechanism 40 may be composed of variable opening valves (eg, EEV) capable of adjusting the opening.

During cooling operation or defrosting operation, the cooling/heating switching valve (2) guides the refrigerant introduced from the oil separator outlet line (5A) to the outdoor heat exchanger connection line (11) and flows from the indoor heat exchanger connection line (21). The refrigerant may be guided to the accumulator suction line 4A.

During heating operation, the cooling/heating switching valve (2) guides the refrigerant in the oil separator outlet line (5A) to the indoor heat exchanger connection line (21) and transfers the refrigerant flowing from the outdoor heat exchanger connection line (11) to the accumulator. It can be guided to the suction line (4A).

The heat pump includes a first bypass line 50 for guiding the refrigerant compressed in the compression unit 3 to the sub-passage 13; a second bypass line 60 for guiding the refrigerant passing through the sub-passage 13 to the first expansion mechanism connection line 31; A flow control valve 70 installed on the first bypass line 50 or the second bypass line 60 may be further included.

The first bypass line 50 may be connected to the indoor heat exchanger connection line 21 and the sub flow path 13 . The first bypass line 50 transfers a part of the refrigerant compressed by the compressor 1 and then flowed to the indoor heat exchanger connection line 21 by the cooling/heating switching valve 2 during the heating operation of the heat pump into a sub-flow path ( 13) can be guided. One end of the first bypass line 50 may be connected to the indoor heat exchanger connection line 21 and the other end may be connected to the sub flow path 13 . When the heat pump is in heating operation and the flow control valve 70 is open, a part of the refrigerant flowing through the indoor heat exchanger connection line 21 flows into the sub-passage 13 through the first bypass line 50. can

The second bypass line 60 may be connected to the sub flow path 13 and the first expansion mechanism connection line 31 . The second bypass line 60 may be connected to guide the refrigerant passing through the sub flow passage 13 to the first expansion mechanism connection line 31 . The second bypass line 60 may have one end connected to the sub-passage 13 and the other end connected to the first expansion mechanism connection line 31 . The second bypass line 60 may include a pair of refrigerant tubes each connected to the flow control valve 70 . The second bypass line 60 is a suction-side second bypass line between the sub-passage 13 and the flow control valve 70 and between the flow control valve 70 and the first expansion mechanism connection line 31. A discharge-side second bypass line may be included.

When the flow control valve 70 is opened, the refrigerant compressed in the compression unit 3 may flow into the sub-passage 13 through the first bypass line 50, and after passing through the sub-passage 13, It may pass through the second bypass line 60 and the flow control valve 70 and be guided to the first expansion mechanism connection line 31 .

The flow control valve 70 may be a variable opening valve (eg, EEV) capable of increasing or decreasing its opening degree (hereinafter referred to as opening degree).

The flow control valve 70 may have a variable opening degree between a minimum opening degree (eg, 32pls) and a maximum opening degree (eg, 1950pls), and the minimum opening degree is the pool at which the flow control valve 70 is maximally closed. It may be closed, and the maximum opening degree may be full open, in which the flow control valve 70 is opened to the maximum.

As the opening of the flow control valve 70 increases, the flow rate of the refrigerant flowing into the sub-passage 13 can increase, and as the opening of the flow control valve 70 decreases, the flow rate of the refrigerant flowing into the sub-passage 13 can be reduced

The opening degree of the flow control valve 70 may be increased or decreased by 10pls/1min in the outdoor heat exchanger anti-icing mode described later.

The opening degree of the flow control valve 70 may be increased or decreased by 50pls/1min to 300pls/1min in a heating low load mode to be described later.

When the heat pump is currently in heating operation and freezing of the outdoor heat exchanger 10 is expected, the opening degree of the flow control valve 70 may be increased and the amount of high-temperature and high-pressure refrigerant passing through the sub-passage 13 may be increased. And, it is possible to prevent the outdoor heat exchanger 10 from freezing.

The heat pump includes a bypass temperature sensor 80 for sensing the temperature of the second bypass line 60 or the sub-passage 13; an outdoor temperature sensor 90 that detects outdoor temperature; A humidity sensor 100 for detecting outdoor humidity may be included.

The bypass temperature sensor 80 is installed in the second bypass line 60 or the sub-passage 13 to detect the temperature, and detects the temperature of the second bypass line 60 or the sub-passage 13. can do. When the bypass temperature sensor 80 is installed in the second bypass line 60 , it may be disposed between the sub-passage 13 and the flow control valve 70 in the second bypass line 60 .

The outdoor temperature detected by the outdoor temperature sensor 90 and the outdoor humidity detected by the humidity sensor 100 may be used to calculate the dew point temperature.

Compressor (5), outdoor heat exchanger (10), outdoor expansion device (30), first bypass line (50), second bypass line (60), flow control valve (70), outdoor temperature sensor (90) ), the humidity sensor 100 and the outdoor fan may be installed in the outdoor unit O.

The indoor heat exchanger 20, the indoor expansion device 40, and the indoor fan may be installed in the indoor unit I. The heat pump may be configured as a multi-type heat pump air conditioner in which a plurality of indoor units (I) are connected to one outdoor unit (O). can

The heat pump includes a controller 120 that controls the flow control valve 70 . The controller 120 may adjust the opening degree of the flow control valve 70 during the heating operation.

The controller 120 can control the compressor 1, the heating/cooling switching valve 2, and the outdoor expansion device 30, and the controller 120 is installed in the outdoor unit O and is installed in the indoor unit I. It may be an outdoor unit controller that communicates.

During the heating operation, the controller 120 may set a target high pressure according to the load of the indoor heat exchanger 20 and may control the frequency of the compressor 1 according to the target high pressure. The controller 120 may drive the compressor 1 at the minimum frequency when the load on the indoor heat exchanger 20 is minimum, and operate the compressor 1 at the maximum frequency when the load on the indoor heat exchanger 20 is maximum. frequency can be driven.

The heat pump may fully open the flow control valve 70 by controlling the maximum opening degree of the flow control valve 70 during the defrosting operation. During the defrosting operation, the high-temperature and high-pressure refrigerant compressed in the compressor 1 defrosts the main tube while passing through the main flow path 12, and the refrigerant flowing from the main flow path 12 to the first expansion mechanism connection line 31 It flows into the sub-passage 13 through the second bypass line 60 and the flow control valve 70, passes through the sub-passage 13 to defrost the subtube, and in the sub-passage 13, the first bypass It may flow to the indoor heat exchanger connection line 21 through the pass line 50 .

The heat pump may close the flow control valve 70 by controlling the minimum opening degree of the flow control valve 70 during the heating operation. During the heating operation of the heat pump, the outdoor heat exchanger 10 cools the main tube by flowing low-temperature and low-pressure refrigerant to the main tube among the main tube and the sub tube during the heating operation, and the sub tube is cooled through the fins 14. and the second bypass line 60 connected to the sub-passage 13 can be gradually cooled. When the temperature of the second bypass line 60 drops to a temperature at which freezing may occur, the controller 120 may increase the opening of the flow control valve 70, and in this case, the compressor 1 may compress The cooled refrigerant may flow into the sub-passage 13 through the first bypass line 50 to heat the sub-passage 13, and the temperature of the outdoor heat exchanger 10 may gradually rise from the subtube. Freezing of the outdoor heat exchanger 10 can be minimized.

That is, the heat pump implements the outdoor heat exchanger icing prevention mode (ie, the outdoor heat exchanger icing prevention mode) to control the opening degree of the flow control valve 70 so that icing does not accumulate in the outdoor heat exchanger 20 during the heating operation. can do. The heat pump can prevent frost from forming on the outdoor heat exchanger 10 while continuously heating the room by the indoor heat exchanger 20 in the outdoor heat exchanger 10 in the anti-icing mode.

Meanwhile, when the heat pump is currently in heating operation and overheating of the indoor heat exchanger 20 is expected, the amount of high-temperature and high-pressure refrigerant flowing into the indoor heat exchanger 20 can be reduced by increasing the opening of the flow control valve 70. It is possible to prevent the indoor heat exchanger 20 from being overheated.

When the condensation temperature and condensation pressure of the indoor heat exchanger 20 excessively rise during heating operation, the heat pump can stop driving the compressor 1 to protect the system. When the opening is increased, excessive increases in the condensation temperature and condensation pressure of the indoor heat exchanger 20 can be minimized, and frequent on/off of the compressor 1 can be minimized.

The heat pump may operate a low load mode (ie, a heating low load mode) in which the opening of the flow control valve 70 is controlled to respond to a low load during the heating operation. The heat pump can continuously heat the room by the indoor heat exchanger 20 in the heating low load mode, and can minimize frequent on/off of the compressor 1.

The controller 120 may fully close the flow control valve 70 during the heating operation, and increase or decrease the opening degree of the flow control valve 70 when the outdoor heat exchanger is in the anti-icing mode or the heating low load mode.

4 is a diagram illustrating the flow of refrigerant in the outdoor heat exchanger of the heat pump in the anti-icing mode in an embodiment of the present invention, and FIG. 5 is a flowchart illustrating the anti-icing mode in the outdoor heat exchanger of the heat pump in the embodiment of the present invention. .

The control unit 120 increases or decreases the opening degree of the flow control valve 70 according to the bypass outlet temperature and the dew point temperature when the outdoor temperature, evaporation temperature, and dew point temperature all correspond to the outdoor heat exchanger freezing prevention conditions. mode can be implemented.

Hereinafter, the outdoor heat exchanger anti-icing mode will be described in detail.

The control unit 120 determines the dew point temperature Td calculated by the outdoor temperature detected by the outdoor temperature sensor 90 and the outdoor humidity detected by the humidity sensor 100 during the heating operation, and the bypass temperature sensor 80. An anti-icing mode of the outdoor heat exchanger may be performed to control the opening of the flow control valve 70 according to the detected bypass outlet temperature Tout.

During the heating operation, the controller 120 controls the freezing of the outdoor heat exchanger according to the outdoor temperature detected by the outdoor temperature sensor 90, the evaporation temperature detected by the low pressure sensor 7, and the dew point temperature calculated from the outdoor temperature and outdoor humidity. It is possible to determine whether or not to implement the prevention mode.

The control unit 120 is in heating operation, the outdoor temperature is lower than the first set temperature (eg, 10 ° C), the evaporation temperature is lower than the second set temperature (eg, 0 ° C), and the outdoor temperature sensor 90 If the dew point temperature calculated from the outdoor temperature detected by the outdoor temperature and the outdoor humidity detected by the humidity sensor 100 is equal to or greater than the bypass outlet temperature Tout detected by the bypass temperature sensor 80, the outdoor heat exchanger anti-icing mode is set. It can be carried out. (S1) (S2)

The control unit 120 may increase or decrease the opening degree of the flow control valve 70 according to the bypass outlet temperature Tout and the dew point temperature during the outdoor heat exchanger anti-icing mode. (S3) (S4) (S5) ( S6)(S7)(S8)

The outdoor heat exchanger anti-icing mode may be an operation in which the opening degree of the flow control valve 70 is increased or decreased according to the bypass outlet temperature Tout and the dew point temperature Td during the heating operation.

When the outdoor heat exchanger is in the anti-icing mode, the control unit 120 detects the bypass outlet temperature Tout detected by the bypass temperature sensor 80 and the outdoor temperature detected by the outdoor temperature sensor 90 and the humidity sensor 100. If it is less than the dew point temperature (Td) calculated from the outdoor humidity, the opening degree of the flow control valve 70 may be increased by the first set opening degree (for example, 10 pls/min). (S3) (S4)

When the bypass outlet temperature (Tout) is greater than the sum of the dew point temperature (Td) and the third set temperature (eg, 5°C) in the outdoor heat exchanger anti-icing mode, the control unit 120 operates the flow control valve 70 The opening degree may be lowered by the second set opening degree (eg, 10 pls/min). (S5)(S6)

Here, the third set temperature is a set temperature for determining whether the opening degree of the flow control valve 70 is reduced, and it is preferable that a specific temperature is set in the temperature range of 2 ° C to 8 ° C.

Here, the second set opening can be set larger or smaller than the first set opening, and can be set equal to the first set opening.

The control unit 120 controls the flow rate when the bypass outlet temperature Tout is less than the sum of the dew point temperature Td and the third set temperature (eg, 5°C) and greater than the dew point temperature in the outdoor heat exchanger icing prevention mode. The opening of the valve 70 can be maintained. (S7) (S8)

The controller 120 may increase the opening degree of the flow control valve 70 twice or more by a first set opening degree at a predetermined cycle while maintaining the bypass outlet temperature Tout below the dew point temperature Td.

When the bypass outlet temperature Tout is less than the sum of the dew point temperature Td and the third set temperature (eg, 5°C) and greater than the dew point temperature Td, the current degree of opening is increased. of can be maintained.

As described above, the controller 120 controls the bypass outlet when the bypass outlet temperature Tout is greater than the sum of the dew point temperature Td and the third set temperature (eg, 5°C) while maintaining the current opening degree. The opening degree of the flow control valve 70 is reduced twice or more by the second set opening degree at a predetermined cycle until the temperature Tout becomes smaller than the sum of the dew point temperature Td and the third set temperature (eg, 5°C). it is possible to do

The control unit 120 may increase or decrease the opening degree of the flow control valve 70 as described above until a condition for releasing the icing prevention mode of the outdoor heat exchanger, which will be described later, is met.

The control unit 120 is in the outdoor heat exchanger anti-icing mode when the heat pump is switched to an operation other than heating (for example, cooling operation) or the heat pump is stopped during the outdoor heat exchanger anti-icing mode. can be released. (S9) (S12)

The controller 120 may cancel the anti-icing mode of the outdoor heat exchanger if the outdoor temperature exceeds the first set temperature (eg, 10° C.) in the middle of the anti-icing mode of the outdoor heat exchanger (S10). (S12)

In the middle of the outdoor heat exchanger anti-icing mode, the control unit 120 determines that the flow control valve 70 is currently at the minimum opening degree and the bypass outlet temperature Tout detected by the bypass temperature sensor 80 is equal to the dew point temperature. If it is greater than the sum of the fourth set temperature (eg, 10°C), the anti-icing mode of the outdoor heat exchanger may be released. (S11) (S12)

Here, the fourth set temperature (eg, 10° C.) may be set higher than the third set temperature (eg, 5° C.). If the bypass outlet temperature Tout is sufficiently higher than the dew point temperature, the possibility of freezing of the outdoor heat exchanger 10 is low. It is possible to stop the anti-icing mode of the outdoor heat exchanger.

That is, the control unit 120 operates when the heat pump is in an operation other than a heating operation (for example, a cooling operation or a defrosting operation), when the outdoor temperature exceeds the first set temperature, or when the flow control valve 70 is at the minimum opening degree and is bypassed. When the outlet temperature Tout is greater than the sum of the dew point temperature and the fourth set temperature, the opening degree of the flow control valve 70 may not be increased or decreased according to the bypass outlet temperature and the dew point temperature.

The controller 120 may control the flow control valve 70 to a minimum opening degree when the ice prevention mode of the outdoor heat exchanger is released. When the flow control valve 70 is opened at least, the refrigerant compressed in the compressor 1 does not flow into the sub-passage 13 from the indoor heat exchanger connection passage 21 through the first bypass passage 50, and The heat exchanger 20 is all flowed from the heat exchanger connection passage 21 to the indoor heat exchanger 20, so that the indoor heat exchanger 20 can be heated more quickly.

6 is a diagram illustrating a refrigerant flow in a heating low load mode of a heat pump according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating a heating low load mode of a heat pump according to an embodiment of the present invention.

The control unit 120 may perform a heating low load mode in which the opening degree of the flow control valve 70 is increased or decreased according to the difference between the current high pressure and the target high pressure.

Hereinafter, the heating low load mode will be described in detail.

During the heating operation, the controller 120 determines that the outdoor temperature is equal to or higher than the set outdoor temperature (eg, 20° C.), and that the current high pressure is equal to the first set pressure (eg, 100 kPa) while the compressor 1 is driven at the minimum frequency. If it is greater than or equal to the sum of the target high pressures, the heating low load mode can be performed. (S21) (S22) (S23)

The control unit 120 controls the initial reference opening degree of the flow control valve 70 at the start of the heating low load mode, and then increases or decreases the opening degree of the flow control valve 70 when the initial set time (eg, 1 minute) has elapsed. The flow control valve 70 can be controlled. The flow control valve 70 may maintain the initial reference opening degree within a set time after being controlled by the initial reference opening degree. Here, the initial reference opening degree may be determined using the capacity of the indoor unit I as a factor. The initial standard opening degree may be smaller as the capacity of the indoor unit (I) in heating operation is larger, and may be larger as the capacity of the indoor unit (I in heating operation) is smaller.

In the heating low load mode, the control unit 120 compares the current high pressure with the sum of the target high pressure and the first set pressure and the sum of the target high pressure and the second set pressure, respectively, to increase or decrease the opening degree of the flow control valve 70. (S24) (S25) (S26) (S27) (S28) (S29)

The heating low load mode may be an operation in which the opening degree of the flow control valve 70 is increased or decreased according to a change in the current high pressure in the middle of the heating operation.

In the heating low load mode, the current high pressure is greater than the sum of the second set pressure (eg, 150 kPa) higher than the first set pressure (eg, 100 kPa) and the target high pressure, the flow control valve ( 70) may be increased by the set increased opening degree (eg, 100plus). (S24) (S25), the control unit 120 adds the initial reference opening degree to the set increased opening degree (eg, 100plus). It is possible to control the flow control valve 70 as.

The controller 120 may reduce the opening of the flow control valve 70 by a set reduction degree (eg, 200 plus) when the current high pressure is less than the sum of the first set pressure and the target high pressure in the heating low load mode. there is. Here, the set reduction degree may be set larger than the set increase opening degree. (S26) (S27) The control unit 120 sets the flow rate control valve 70 at an opening degree obtained by subtracting the set reduction degree (eg, 200plus) from the initial reference opening degree. ) can be controlled.

The control unit 120 controls the heating low load mode when the current high pressure is less than or equal to the sum of the second set pressure (eg, 150 kPa) and the target high pressure, and is greater than or equal to the sum of the first set pressure (eg, 100 kPa) and the target high pressure. , It is possible to maintain the opening of the flow control valve 70. (S28) (S29)

The control unit 120 may increase the opening degree of the flow control valve 70 two or more times by a set incremental opening degree at a predetermined cycle while the current high pressure is greater than the sum of the second set pressure (eg, 150 kPa) and the target high pressure. . Thereafter, the control unit 120 controls the opening degree when the current high pressure is less than or equal to the sum of the second set pressure (eg, 150 kPa) and the target high pressure and greater than or equal to the sum of the first set pressure (eg, 100 kPa) and the target high pressure. The increased current opening degree can be maintained.

As described above, while maintaining the current opening degree, if the current high pressure is smaller than the sum of the first set pressure and the target high pressure, the control unit 120 determines that the current high pressure is the sum of the first set pressure (eg, 100 kPa) and the target high pressure. The opening degree of the flow control valve 70 may be reduced two or more times by a set reduction degree (for example, 200 plus) at a predetermined cycle until it becomes abnormal.

The control unit 120 may increase or decrease the opening degree of the flow control valve 70 as described above until the release condition of the heating low load mode, which will be described later, is met.

The control unit 120 may release the heating low load mode when the heat pump is in operation other than heating operation (for example, cooling operation or defrosting operation) or when the heat pump is stopped during the heating low load mode (S30). (S33)

The control unit 120 may release the heating low load mode if the outdoor temperature is less than the outdoor set temperature (eg, 20° C.) during the heating low load mode (S31) (S33).

The control unit 120 may release the heating low load mode when the flow rate control valve 70 is at the minimum opening degree and the compressor 1 is driven exceeding the minimum frequency in the middle of the heating low load mode. (S32) (S33)

That is, the control unit 120 determines whether the heat pump is in operation other than heating operation (eg, cooling operation or defrosting operation) during the heating low load mode, or when the outdoor temperature is less than the set outdoor temperature (eg, 20° C.) , If the flow control valve 70 is at the minimum opening degree and the compressor 1 is driven exceeding the minimum frequency, the opening degree of the flow control valve 70 may not be increased or decreased according to the change in the current high pressure.

The control unit 120 may control the flow control valve 70 to a minimum opening degree when the heating low load mode is released. When the flow control valve 70 is opened at least, the refrigerant compressed in the compressor 1 does not flow into the sub-passage 13 from the indoor heat exchanger connection passage 21 through the first bypass passage 50, and The heat exchanger 20 is all flowed from the heat exchanger connection passage 21 to the indoor heat exchanger 20, so that the indoor heat exchanger 20 can be heated more quickly.

The term 'line' described in this specification may refer to a tube or pipe through which a refrigerant may pass.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments.

The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

1: Compressor 2: Cooling/heating selector valve
10: outdoor heat exchanger 12: main flow
13: sub-flow 20: indoor heat exchanger
30: outdoor expansion mechanism 40: indoor expansion mechanism
50: first bypass line 60: second bypass line
70: flow control valve 90: outdoor temperature sensor
100: humidity sensor 120: control unit

Claims (13)

a compression unit having a compressor and a cooling/heating switching valve;
an outdoor heat exchanger connected to the compression unit through a connection line between the outdoor heat exchanger and having a main flow path and a sub flow path;
an indoor heat exchanger connected to the compression unit through a connection line between the indoor heat exchanger and the indoor heat exchanger;
an outdoor expansion mechanism connected to the main flow path through a first expansion mechanism connection line;
an indoor expansion device connected to the indoor heat exchanger through a connection line to the second expansion device and connected to the outdoor expansion device through a connection line to the third expansion device;
a first bypass line for guiding the refrigerant compressed in the compression unit to the sub-passage;
a second bypass line for guiding the refrigerant passing through the sub-passage to the first expansion mechanism connection line;
a flow control valve installed in the first bypass line or the second bypass line;
a bypass temperature sensor for sensing a temperature of the second bypass line or sub-passage;
an outdoor temperature sensor for sensing outdoor temperature;
a humidity sensor for detecting outdoor humidity;
During the heating operation, the flow control valve operates according to the dew point temperature calculated by the outdoor temperature detected by the outdoor temperature sensor and the outdoor humidity detected by the humidity sensor, and the bypass outlet temperature detected by the bypass temperature sensor. It includes a control unit that performs an anti-icing mode of the outdoor heat exchanger that controls the opening degree,
The control unit performs a heating low load mode when the outdoor temperature is equal to or greater than the outdoor set temperature during the heating operation and the current high pressure is greater than or equal to the sum of the first set pressure and the target high pressure while the compressor is driven at the minimum frequency;
The control unit increases the opening of the flow control valve by a set increased opening when the current high pressure is greater than the sum of the target high pressure and the second set pressure, which is higher than the first set pressure, in the heating low load mode.
According to claim 1,
wherein the controller performs the anti-icing mode of the outdoor heat exchanger when the outdoor temperature is equal to or less than the first set temperature, the evaporation temperature is less than the second set temperature, and the dew point temperature is equal to or greater than the bypass outlet temperature. According to claim 1,
The control unit increases the opening of the flow control valve by a first set opening when the bypass outlet temperature is equal to or less than the dew point temperature in the outdoor heat exchanger in an anti-icing mode. According to claim 1,
wherein the control unit lowers the opening of the flow control valve by a second set opening when the bypass outlet temperature is greater than the sum of the dew point temperature and the third set temperature in the outdoor heat exchanger anti-icing mode. According to claim 4,
wherein the control unit maintains an opening degree of the flow control valve when the bypass outlet temperature is less than the sum of the dew point temperature and the third set temperature and greater than the dew point temperature in the outdoor heat exchanger anti-icing mode.
According to claim 5,
The control unit controls a fourth set temperature when the heat pump is in operation other than the heating operation, when the outdoor temperature exceeds the first set temperature, or when the flow control valve is at least open and the bypass outlet temperature is higher than the dew point temperature and the third set temperature. If greater than the sum of , the heat pump releases the anti-icing mode of the outdoor heat exchanger.
delete delete According to claim 1,
The control unit controls the flow control valve to an initial reference opening degree when the heating low load mode is started, and increases or decreases the opening degree of the flow control valve when an initial set time elapses after controlling the flow control valve to an initial reference opening degree. .
According to claim 1,
The control unit reduces the opening degree of the flow control valve by a set reduction degree when the current high pressure is less than the sum of the first set pressure and the target high pressure in the heating low load mode.
According to claim 10,
The set reduction degree is greater than the set increase opening degree of the heat pump. According to claim 1,
wherein the control unit maintains an opening degree of the flow control valve when the current high pressure is less than or equal to the sum of the second set pressure and the target high pressure and greater than or equal to the sum of the first set pressure and the target high pressure in the heating low load mode.
According to claim 1,
The heat pump to release the heating low load mode when the heat pump is in operation other than the heating operation, the outdoor temperature is less than the outdoor set temperature, or the flow control valve is at a minimum opening degree and the compressor is in operation exceeding a minimum frequency.

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