KR20200034474A - chiller - Google Patents

Abstract

The present invention relates to a chiller which can freeze an evaporator in a state in which a compressor is turned off when outdoor temperature is reduced, thereby reducing power consumption. The chiller can comprise: an accumulator for separating a gas-phase refrigerant and a liquid-phase refrigerant between the evaporator and the compressor; a refrigerant storage pipe connected to the accumulator; a receiver connected to the refrigerant storage pipe; a refrigerant flow pipe having one end connected to the receiver and the other end connected to a refrigerant pipe between a main expansion mechanism and the evaporator; a refrigerant pump installed in the refrigerant flow pipe; and a bypass pipe and a receiver inlet pipe through which the refrigerants pass when the refrigerants are circulated by the refrigerant pump.

Description

Chiller

The present invention relates to a chiller that performs an air conditioning function.

The chiller system supplies cold water to a cold water demand source, and may include a chiller and a cold water demand source.

The chiller includes a compressor, a condenser, an expansion mechanism, and an evaporator, and the evaporator is configured to exchange water and refrigerant, and the cold water demand includes a separate heat exchanger (that is, a cold water coil) through which water exchanged with the refrigerant passes. The heat exchanger can cool the room by cooling the air blown into the room.

The demand for cold water may be a water-cooled air conditioner that exchanges air with cold water, and is composed of an air handling unit (AHU) that mixes indoor and outdoor air, heat exchanges the mixed air with cold water, and discharges it to the room. It is possible to be installed, it is possible to be composed of a fan coil unit (FCU: Fan Coil Unit) that is installed indoors to intake indoor air to exchange heat with cold water and then discharged into the room, and it is composed of a floor piping unit embedded in the floor of the room It is also possible.

The present invention is to provide a chiller capable of cooling the evaporator in a state where the compressor is turned off when the outdoor temperature is low, thereby reducing power consumption.

The chiller according to an embodiment of the present invention includes an accumulator for separating gaseous refrigerant and liquid refrigerant between an evaporator and a compressor, a refrigerant storage pipe connected to the accumulator, a receiver connected to the refrigerant storage pipe, and one end connected to the receiver and the other end main It may include a refrigerant flow pipe connected to a refrigerant pipe between the expansion mechanism and the evaporator, a refrigerant pump installed in the refrigerant flow pipe, a bypass pipe through which the refrigerant passes when the refrigerant is circulated by the refrigerant pump, and a receiver inlet pipe.

It includes a control unit that selectively performs normal operation and power reduction operation according to the outdoor temperature, and the control unit performs power reduction operation when the outdoor temperature is less than the set temperature, and cools the refrigerant in the refrigerant pipe and liquid refrigerant in the accumulator during the power reduction operation. After performing the refrigerant storage mode for storing in the receiver, a heat exchange mode in which the refrigerant of the receiver is circulated through the evaporator, the condenser, and the receiver may be performed.

If the outdoor temperature is greater than or equal to the set temperature in the middle of the power reduction operation, the control unit may stop the power reduction operation and control the normal operation.

The control unit may initiate the heat exchange mode after performing the refrigerant storage mode for a predetermined time.

The control unit may control the expansion mechanism to the refrigerant expansion opening during normal operation and the expansion mechanism to the minimum opening in the power reduction mode.

Further comprising a sub-expansion mechanism for expanding the refrigerant between the refrigerant pump and the evaporator, the control unit may control the sub-expansion mechanism to the maximum opening in the storage mode, and to control the sub-expansion mechanism to the refrigerant expansion opening in the heat exchange mode.

Further comprising a first valve that is opened and closed between the evaporator and the accumulator, the controller can open the first valve in normal operation and refrigerant storage mode and close in the heat exchange mode.

The first end is connected to the refrigerant pipe between the evaporator and the accumulator, the other end is connected to the refrigerant pipe between the compressor and the condenser, and further includes a second valve opened and closed in the bypass pipe, and the control unit controls the second valve. It can be closed in normal operation and refrigerant storage mode and open in heat exchange mode.

It further includes a third valve that is opened and closed in the refrigerant storage pipe, and the controller can open the third valve in the refrigerant storage mode and close it in the normal operation and heat exchange mode.

One end is connected to the refrigerant pipe between the condenser and the main expansion mechanism, the other end further comprises a receiver inlet pipe connected to the receiver, and a fourth valve opened and closed at the receiver inlet pipe, and the controller opens the fourth valve in the heat exchange mode It can be closed during normal operation and refrigerant storage mode.

In the chiller according to an embodiment of the present invention, since the refrigerant can be circulated in the state in which the compressor is turned off, the receiver, the refrigerant pump, the evaporator, and the condenser can be circulated, so the evaporator can continuously cool the cold water while minimizing power consumption.

In addition, since the refrigerant is collected in the receiver and the refrigerant circulates through the receiver, the refrigerant pump, the evaporator, and the condenser, a large amount of refrigerant flows through the evaporator to increase cooling efficiency.

In addition, the chiller has an advantage that can reduce the power consumption of the compressor when the outside temperature is relatively low load.

In addition, the chiller may store the refrigerant in the receiver in the refrigerant storage mode by using a valve that is opened and closed between the evaporator and the accumulator, and block the refrigerant flow to the compressor in the heat exchange mode.

In addition, the chiller can minimize the refrigerant flow resistance by minimizing the circulation path of the refrigerant by including a bypass pipe guiding the refrigerant discharged from the evaporator to the condenser, and in the normal mode using a valve opened and closed in the bypass pipe. The refrigerant can be guided to the compressor, and the refrigerant can be guided to the condenser in the heat exchange mode.

In addition, by using a refrigerant storage pipe connecting the accumulator and the receiver and a valve that is opened and closed in the refrigerant storage pipe, the chiller stores the refrigerant remaining in the refrigerant pipe in the receiver, thereby increasing the flow rate of refrigerant during circulation of the refrigerant to improve cooling efficiency. .

In addition, the chiller blocks the refrigerant flow to the receiver in the normal mode by using a receiver inlet pipe for guiding the refrigerant discharged from the condenser to the receiver, and a valve opened and closed at the receiver inlet pipe, and rapidly cools the refrigerant to the receiver in the heat exchange mode. I can guide you.

1 is a block diagram of a chiller system to which a chiller according to an embodiment of the present invention is applied.
2 is a control block diagram of a chiller according to an embodiment of the present invention.
3 is a flowchart illustrating a method of operating a chiller according to an embodiment of the present invention.
FIG. 4 is a flowchart specifically showing the implementation of the power reduction operation of FIG. 3.
5 is a normal operation and power reduction operation according to an embodiment of the present invention, a compressor, a refrigerant pump, an outdoor fan, a main expansion mechanism, a sub expansion mechanism, an evaporator outlet valve, a condenser inlet valve, and a refrigerant storage valve. Wow, it is a diagram showing the control of each of the receiver inlet valve.
6 is a view showing a refrigerant flow path during normal operation of a chiller according to an embodiment of the present invention.
7 is a view showing a refrigerant flow path in a refrigerant storage mode of a chiller according to an embodiment of the present invention.
8 is a view showing a refrigerant flow path in a heat exchange mode of a chiller according to an embodiment of the present invention.

Hereinafter, a specific embodiment of the present invention will be described in detail with the accompanying drawings.

1 is a block diagram of a chiller system to which a chiller according to an embodiment of the present invention is applied.

The chiller 10 of this embodiment may be connected to the cold water demand destination 2, and the chiller 10 and the cold water demand destination 2 may constitute a chiller system capable of supplying cold water to the cold water demand destination 2.

The chiller 10 is a cold water supply unit that supplies cold water to the heat exchanger 3 of the cold water demand destination 2 using a refrigeration cycle.

The chiller 10 may perform normal operation or power reduction operation according to the outdoor temperature.

General operation means that the refrigerant circulates through the compressor (11), the condenser (12), the main expansion mechanism (13), and the evaporator (14), and power reduction operation in the state where the compressor (11) is turned off. It may mean an operation in which the refrigerant circulates.

The power reduction operation is an operation mode in which power consumption can be reduced more than in the general operation, and may be an operation in which the refrigerant circulates while the compressor 11 is turned off. Power reduction operation will be described in detail later.

The chiller 10 includes a compressor 11 for compressing a refrigerant, a condenser 12 in which the refrigerant compressed in the compressor 11 is condensed, a main expansion mechanism 13 in which the refrigerant condensed in the condenser 12 is expanded, and a main expansion The refrigerant expanded in the mechanism 13 includes an evaporator 14 that is evaporated by heat exchange with water, and the compressor 11, the condenser 12, the main expansion mechanism 13, and the evaporator 14 form a refrigeration cycle. .

The chiller 10 may be divided into a water cooling type in which heat medium is scattered in a cooling tower to dissipate heat, and an air cooling type in which heat exchangers through which heat medium flows are in contact with air to radiate heat.

The compressor 11 is made of a variable-capacity type compressor having a variable operating capacity, and a plurality of compressors are partially or completely driven depending on a load, or an inverter compressor or the like.

The compressor 11 can compress the refrigerant. The compressor 11 may be selectively driven according to the operating state of the chiller. Specifically, the compressor 11 may be turned on during the normal operation of the chiller, and may be turned off when the power reduction operation of the chiller 10 is performed.

The compressor 11 may be connected to the condenser 12 and the compressor outlet pipe 21. The compressor outlet pipe 21 may be provided with an oil separator 15 for separating refrigerant oil and oil out of the compressor 11. The oil separator 15 may be connected to the compressor 11 and the oil recovery pipe 16, and the oil separated from the refrigerant in the oil separator 15 may be recovered to the compressor through the oil recovery pipe 16.

The condenser 12 is a refrigerant condensed by outdoor air blown by the outdoor fan 17, and the refrigerant flowing through the compressor outlet pipe 21 may be heat exchanged with outdoor air to be condensed by air cooling.

The condenser 12 may condense the refrigerant compressed in the compressor 11. The refrigerant may pass through the condenser 12 during normal operation and in heat exchange mode.

The evaporator 14 may be connected to the cold water demand source 2 and the water pipes 22 and 23, and may be a cooler that cools water as the refrigerant expanded in the main expansion mechanism 13 evaporates. In the evaporator 14, a refrigerant passage 14A through which the refrigerant passes and a water passage 14B through which the water passes are formed with a heat exchange member interposed therebetween.

An example of the evaporator 14 may be composed of a shell and tube type heat exchanger. The evaporator 14 may include a shell having a plurality of inner tubes through which water passes and a water passage, and a refrigerant passage formed outside the plurality of inner tubes and through which refrigerant flows.

As another example of the evaporator 14, it is possible that the water flow path and the refrigerant flow path are configured as a plate heat exchanger disposed with a plate-shaped heat exchange member interposed therebetween.

Another example of the evaporator 14 may be configured as a double tube heat exchanger connected to the heat exchanger 3 and the water pipes 22 and 23 of the cold water demand destination 2. In this case, at least one inner tube and an outer tube surrounding the inner tube may be included.

This embodiment is not limited to the type of the evaporator 14, and is applicable as long as the refrigerant passage and the cold water passage are separated with a heat transfer member therebetween.

A cold water pump 18 for pumping cold water may be installed in the water pipes 22 and 23 to allow the cold water to circulate through the evaporator 14 and the cold water demand 2.

The chiller 10 includes an accumulator 31, a refrigerant storage pipe 32 connected to the accumulator 31, a receiver 33 connected to the refrigerant storage pipe 32, and a refrigerant flow pipe connected to the receiver 33 ( 34), a refrigerant pump (35) installed in the refrigerant flow pipe (34), and a bypass pipe (36) through which refrigerant flows when refrigerant is circulated by the refrigerant pump (35) and a receiver inlet pipe (37) may be included. have.

The power reduction operation is an operation mode for circulating the refrigerant while reducing power consumption during normal operation, and may include a refrigerant storage mode for storing the refrigerant in the receiver 33 and a heat exchange mode for circulating the refrigerant in the receiver 33. have. In the refrigerant storage mode, the refrigerant circulates through the receiver (33), the sub-expansion mechanism (38), the evaporator (14) and the accumulator (31), and in the heat exchange mode, the refrigerant is the receiver (33), the sub-expansion mechanism (38), and the evaporator ( 14) and the condenser 12.

An evaporator inlet pipe 51 may be connected between the condenser 12 and the evaporator 14. The evaporator inlet pipe 51 is a condenser discharge pipe 51A, which is a refrigerant flow path between the condenser 12 and the main expansion mechanism 13, and a main refrigerant flow path between the main expansion mechanism 13 and the sub expansion mechanism 38. The expansion pipe 51B may include a sub-expansion pipe 51C between the sub-expansion mechanism 38 and the evaporator 14.

The main expansion mechanism 13 may be installed in the evaporator inlet pipe 51.

The main expansion mechanism 13 is to expand the flowing refrigerant, and may be configured with an electronic expansion valve such as EEV or LEV, which can adjust the opening degree. The main expansion mechanism 13 may be adjusted to a minimum opening degree or a maximum opening degree, or may be adjusted to a refrigerant expansion opening degree larger than the minimum opening degree and smaller than the maximum opening degree. The minimum opening degree may be a full close in which the main expansion mechanism 13 is maximized, and the maximum opening degree may be a full opening in which the main expansion mechanism 13 is opened to the maximum.

The larger the opening degree of the main expansion mechanism 13, the larger the flow rate of the flowing refrigerant may be increased, and the smaller the opening degree of the main expansion mechanism 13, the smaller the flow rate of the refrigerant may be.

In the evaporator 14, the expanded refrigerant may be exchanged with water.

An evaporator outlet pipe 52 is connected to the evaporator 14, and a refrigerant exchanged in the evaporator 14 may pass through the evaporator outlet pipe 52.

The evaporator outlet pipe 52 may have one end connected to the evaporator 14 and the other end connected to the accumulator 31. The evaporator outlet pipe 52 is an evaporator discharge pipe 52A, which is a refrigerant flow path between the evaporator outlet valve 41 and the evaporator 14, which will be described later, and an accumulator which is a refrigerant flow path between the evaporator outlet pipe 52 and the accumulator 32. It may include an inlet pipe (52B).

The accumulator 31 may separate the gaseous refrigerant and the liquid refrigerant between the evaporator 14 and the compressor 11.

The accumulator 31 may be connected to an evaporator outlet pipe 52, a refrigerant storage pipe 32, and a compressor inlet pipe 53.

The refrigerant that has passed through the evaporator outlet pipe 52 may be introduced into the accumulator 31. The accumulator 31 separates the gaseous refrigerant and the liquid refrigerant, and can guide the gaseous refrigerant to the compressor 11 through the compressor inlet pipe 53, and the liquid refrigerant to the receiver 33 through the refrigerant storage pipe 32. You can guide.

A refrigerant storage pipe 32, a receiver inlet pipe 37, and a refrigerant flow pipe 34 may be connected to the receiver 33.

The refrigerant storage pipe 32 may have one end connected to the accumulator 31 and the other end connected to the receiver 33.

One end of the receiver inlet pipe 37 is connected to the evaporator inlet pipe 51 between the main expansion mechanism 13 and the condenser 12, and the other end can be connected to the receiver 33. That is, the receiver inlet pipe 37 may be connected to the condenser discharge pipe 51A and the receiver 33.

The refrigerant flow pipe 34 may have one end connected to the receiver 33 and the other end connected between the main expansion mechanism 13 and the sub expansion mechanism 38 of the evaporator inlet pipe 51. That is, the refrigerant flow pipe 34 may be connected to the main expansion pipe 51B, and the refrigerant of the receiver 33 may be guided to the main expansion pipe 51B.

The refrigerant pump 35 may be installed in the refrigerant flow pipe 34. The refrigerant pump 35 may discharge refrigerant stored in the receiver 33 into the refrigerant flow pipe 34. The refrigerant pump 35 may circulate the refrigerant in the power reduction mode.

The sub-expansion mechanism 38 may expand the refrigerant between the refrigerant pump 35 and the evaporator 14. For example, the sub-expansion mechanism 38 may be installed between a point at which the evaporator 14 and the refrigerant flow pipe 34 are connected among the inlet pipe 51 of the evaporator, and the refrigerant passing through the refrigerant flow pipe 34 You can adjust the flow rate.

The sub-expansion mechanism 38 may be configured as an electronic expansion valve such as EEV or LEV, which can be adjusted in opening degree. The sub-expansion mechanism 38 may be adjusted to a minimum opening degree or a maximum opening degree, or may be adjusted to a refrigerant opening opening degree larger than the minimum opening degree and smaller than the maximum opening degree. The minimum opening degree may be a full close in which the sub-inflating mechanism 38 is maximized, and the maximum opening degree may be a full open in which the sub-inflating mechanism 38 is opened to the maximum.

The larger the opening degree of the sub-expansion mechanism 38, the larger the flow rate of the flowing refrigerant may be increased, and the smaller the opening degree of the sub-expansion mechanism 38, the smaller the flow rate of the refrigerant may be.

A bypass pipe 36 may be connected to the evaporator outlet pipe 52. The bypass pipe 36 may have one end connected to the evaporator outlet pipe 52 and the other end connected to the compressor outlet pipe 21. Specifically, the bypass pipe 36 is one end is connected to the refrigerant pipe between the evaporator 14 and the evaporator outlet valve 41, the other end can be connected to the refrigerant pipe between the condenser 12 and the oil separator 15 have.

In addition, the chiller 10 may further include at least some or all of an evaporator outlet valve 41, a condenser inlet valve 42, a refrigerant storage valve 43, and a receiver inlet valve 44.

Each of the evaporator outlet valve 41, the condenser inlet valve 42, the refrigerant storage valve 43, and the receiver inlet valve 44 may be solenoid valves, controlled by on or off, and when on It is full open and can be full closed when off control.

The evaporator outlet valve 41 may be installed in the evaporator outlet pipe 52. Preferably, the evaporator outlet valve 41 may be installed between the point where the bypass pipe 36 is connected and the accumulator 31 among the evaporator outlet pipes 52. The evaporator outlet valve 41 may open or close the refrigerant passage from the evaporator 14 to the accumulator 31.

The condenser inlet valve 42 may be installed in the bypass pipe 36. At this time, the bypass pipe 36 is one end is connected to the evaporator outlet pipe 52 between the evaporator 14 and the evaporator outlet valve 41, the other end is a compressor between the oil separator 15 and the condenser 12 It may be connected to the outlet pipe (21). The condenser inlet valve 42 may open or close the refrigerant passage from the evaporator 14 to the condenser 12.

The refrigerant storage valve 43 may be installed in the refrigerant storage pipe 32. The refrigerant storage valve 43 may open or close the refrigerant passage from the accumulator 31 to the receiver 33.

The receiver inlet valve 44 may be installed in the receiver inlet pipe 37. The receiver inlet valve 44 may open or close the refrigerant flow path from the condenser 12 to the receiver 33.

2 is a control block diagram of a chiller according to an embodiment of the present invention, FIG. 3 is a flowchart showing a method of operating a chiller according to an embodiment of the present invention, and FIG. 4 specifically shows the power reduction operation of FIG. 3 5 is a flow chart of a compressor, a refrigerant pump, an outdoor fan, a main expansion mechanism, a sub expansion mechanism, an evaporator outlet valve, and a condenser inlet valve during normal operation and power reduction operation according to an embodiment of the present invention. It is a diagram showing the control of each of the refrigerant storage valve and the receiver inlet valve.

The chiller 10 may further include an outdoor temperature sensor 30 for sensing the outdoor temperature, a timer 39, and a control unit 40 for controlling the operation of the chiller 10.

The outdoor temperature sensor 30 may be installed around the condenser 12 to sense the outdoor temperature, and transmit the outdoor temperature information to the control unit 40. The outdoor temperature sensor 30 may be installed to be spaced apart from the condenser 12 in which the outside air and the refrigerant exchange heat.

The timer 39 may measure the passage of time, and transmit the measured time information to the control unit 40.

The control unit 40 includes a compressor 11, a condenser 12, a main expansion mechanism 13, a sub expansion mechanism 38, an evaporator 14, a refrigerant pump 35, an outdoor fan 17, an evaporator outlet valve ( 41), the condenser inlet valve 42, the refrigerant storage valve 43 and the receiver inlet valve 44 can be controlled respectively.

The control unit 40 may be controlled to perform a normal operation, a power reduction operation (refrigerant storage mode or heat exchange mode) based on information transmitted from the outdoor temperature sensor 30 and the timer 39.

The controller 40 may selectively perform normal operation and power reduction operation according to the outdoor temperature. Specifically, the control unit 40 may perform normal operation when the outdoor temperature is greater than or equal to the set temperature, and perform power reduction operation when the outdoor temperature is less than the set temperature.

Referring to FIG. 3, the control unit 40 may perform normal operation (S11).

The control unit 40 may turn on the compressor 11 during normal operation to flow the refrigerant.

As shown in FIG. 5, during normal operation, the control unit 40 controls the compressor 11 to ON, controls the refrigerant pump 35 to OFF, controls the outdoor fan 17 to ON, and expands the main. The mechanism 13 is controlled to the refrigerant expansion opening, the sub-expansion mechanism 38 is controlled to the maximum opening, the evaporator outlet valve 41 is opened, the condenser inlet valve 42 is closed, and the refrigerant storage valve 43 ), And the receiver inlet valve 44 can be closed.

6 is a view showing a refrigerant flow path during normal operation of a chiller according to an embodiment of the present invention.

As shown in FIG. 6, the refrigerant of the chiller 10 includes a compressor 11, a condenser 12, a main expansion mechanism 13, a sub expansion mechanism 38, and an evaporator 14 during normal operation. Wow, the accumulator 31 can be circulated.

Again, FIG. 3 will be described.

The control unit 40 may detect the outdoor temperature during normal operation (S12).

The control unit 40 may control the outdoor temperature sensor 30 to detect the outdoor temperature during normal operation. For example, the outdoor temperature sensor 30 may detect the outdoor temperature every set period.

The control unit 40 may determine whether the outdoor temperature is less than the set temperature (S13).

Here, the outdoor temperature indicates the temperature sensed by the outdoor temperature sensor 30, and the set temperature may be set through an input unit (not shown), or may be a temperature previously stored in a storage unit (not shown). For example, the set temperature may be 5 ° C, but this is only an example and is not limited thereto.

The control unit 40 may maintain normal operation when the outdoor temperature is greater than or equal to the set temperature.

The control unit 40 may perform power reduction operation when the outdoor temperature is less than the set temperature (S14).

The power reduction operation may include a refrigerant storage mode and a heat exchange mode, and when the power reduction operation is performed, the refrigerant storage mode and the heat exchange mode may be sequentially performed.

The refrigerant storage mode may be an operation mode in which the refrigerant remaining in the refrigerant pipe and the liquid refrigerant of the accumulator 31 are stored in the receiver 33. At this time, the refrigerant pipe may include at least one of the evaporator inlet pipe 51, the evaporator outlet pipe 52, the refrigerant storage pipe 32 and the refrigerant flow pipe 34.

The heat exchange mode may be an operation mode in which the refrigerant stored in the receiver 33 circulates and heat exchanges with water in the evaporator 14.

Referring to FIG. 4, when power reduction operation is performed, the controller 40 may perform a refrigerant storage mode (S111).

As shown in FIG. 5, the control unit 40 may switch to the refrigerant storage mode from normal operation at the time t1, and in the refrigerant storage mode, the control unit 40 controls the compressor 11 to be off, and the refrigerant pump ( 35) is controlled to ON, the outdoor fan (17) is controlled to OFF, the main expansion mechanism (13) is controlled to the minimum opening, the sub-expansion mechanism (38) is controlled to the maximum opening, and the evaporator outlet valve (41) ) Can be opened, the condenser inlet valve 42 is closed, the refrigerant storage valve 43 is opened, and the receiver inlet valve 44 can be closed.

7 is a view showing a refrigerant flow path in a refrigerant storage mode of a chiller according to an embodiment of the present invention.

As illustrated in FIG. 7, the refrigerant of the chiller 10 may circulate through the receiver 33, the sub-expansion mechanism 38, the evaporator 14, and the accumulator 31 in the refrigerant storage mode.

Again, FIG. 4 will be described.

The control unit 40 may determine whether the operation time to the refrigerant storage mode is longer than the set time (S112).

The control unit 40 may control the timer 39 to measure the operation time in the refrigerant storage mode. The timer 39 may start counting at the time when the refrigerant storage mode is performed to measure the operation time to the refrigerant storage mode.

The set time may be set through an input unit (not shown), or may be a time previously stored in a storage unit (not shown). For example, the set time may be 10 minutes, but this is only an example and is not limited thereto.

The control unit 40 may maintain the refrigerant storage mode when the operation time to the refrigerant storage mode is less than the set time.

If the operation time to the refrigerant storage mode is greater than or equal to the set time, the control unit 40 may perform a heat exchange mode (S113).

As shown in FIG. 5, the control unit 40 may switch from the refrigerant storage mode to the heat exchange mode at the time t2, and in the heat exchange mode, the control unit 40 controls the compressor 11 to be off, and the refrigerant pump 35 ) Is controlled to ON, the outdoor fan 17 is controlled to ON, the main expansion mechanism 13 is controlled to the minimum opening degree, the sub-expansion mechanism 38 is controlled to the refrigerant expansion opening degree, and the evaporator outlet valve 41 is controlled. ) Is closed, the condenser inlet valve 42 is opened, the refrigerant storage valve 43 is closed, and the receiver inlet valve 44 can be opened.

8 is a view showing a refrigerant flow path in a heat exchange mode of a chiller according to an embodiment of the present invention.

As illustrated in FIG. 8, the refrigerant of the chiller 10 may circulate in the heat exchange mode, the receiver 33, the sub expansion mechanism 38, the evaporator 14, and the condenser 12.

Again, FIG. 3 will be described.

The control unit 40 may detect the outdoor temperature during power reduction operation (S15).

That is, the control unit 40 may control the outdoor temperature sensor 30 to detect the outdoor temperature during the refrigerant storage mode and the heat exchange mode.

The control unit 40 may determine whether the outdoor temperature is less than the set temperature (S16).

Here, the set temperature is the same as the set temperature in step S12.

The control unit 40 may maintain power reduction operation when the outdoor temperature is less than the set temperature.

Meanwhile, the control unit 40 may perform normal operation when the outdoor temperature is greater than or equal to the set temperature. That is, if the outdoor temperature is higher than the set temperature, the control unit 40 may switch from power reduction operation to normal operation. Referring to FIG. 5, the control unit 40 may switch from heat exchange mode to normal operation at a time t3, where t3 may be a time when the outdoor temperature is detected above a set temperature. Meanwhile, the control unit 40 may switch from the refrigerant storage mode to the normal operation when the external temperature is detected to be higher than the set temperature even during the refrigerant storage mode.

If the outdoor temperature is higher than the set temperature, it may be an escape condition of power reduction operation. If the outdoor temperature exceeds the set temperature during the power reduction operation, the control unit 40 may stop the power reduction operation and control the normal operation.

When the operation time to the refrigerant storage mode is longer than the set time, it may be a starting condition of the heat exchange mode. The control unit 40 may initiate the heat exchange mode after performing the refrigerant storage mode for a predetermined time.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations 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 spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments.

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

11: Compressor 12: Condenser
13: main expansion mechanism 14: evaporator
31: accumulator 32: refrigerant storage piping
33: receiver 34: refrigerant flow piping
35: refrigerant pump 36: bypass piping '
37: receiver inlet pipe 38: sub-expansion mechanism

Claims (10)

In the chiller in which the refrigerant circulates through the compressor, the condenser, the main expansion mechanism and the evaporator,
An accumulator for separating gaseous refrigerant and liquid refrigerant between the evaporator and the compressor;
A refrigerant storage pipe connected to the accumulator;
A receiver connected to the refrigerant storage pipe;
A refrigerant flow pipe having one end connected to the receiver and the other end connected to a refrigerant pipe between the main expansion mechanism and the evaporator;
A refrigerant pump installed in the refrigerant flow pipe;
A chiller including a bypass pipe through which the refrigerant passes when the refrigerant is circulated by the refrigerant pump and a receiver inlet pipe. According to claim 1,
Includes a control unit that selectively performs normal operation and power reduction operation according to the outdoor temperature,
If the outdoor temperature is less than the set temperature, the control unit performs power reduction operation,
After power reduction operation, after performing a refrigerant storage mode for storing the refrigerant in the refrigerant pipe and the liquid refrigerant in the accumulator in the receiver,
A chiller that performs a heat exchange mode for circulating the refrigerant of the receiver through an evaporator, a condenser, and a receiver. According to claim 2,
The control unit stops the power reduction operation when the outdoor temperature is greater than or equal to a set temperature during the power reduction operation, and controls the chiller to control the normal operation. According to claim 2,
The control unit performs the refrigerant storage mode for a predetermined time and then starts the heat exchanger mode. According to claim 2,
The control unit controls the expansion mechanism to the refrigerant expansion opening during normal operation, and the chiller to control the expansion mechanism to the minimum opening in the power reduction mode. According to claim 2,
Further comprising a sub-expansion mechanism for expanding the refrigerant between the refrigerant pump and the evaporator,
The control unit controls the sub-expansion mechanism to the maximum opening degree in the storage mode, and controls the sub-expansion mechanism to the refrigerant expansion opening degree in the heat exchange mode. According to claim 2,
Further comprising a first valve that is opened and closed between the evaporator and the accumulator,
The control unit opens the first valve in the normal operation and the refrigerant storage mode, and closes the heat exchanger in the chiller. According to claim 2,
A bypass pipe having one end connected to a refrigerant pipe between the evaporator and the accumulator, and the other end connected to a refrigerant pipe between the compressor and the condenser;
Further comprising a second valve that is opened and closed in the bypass pipe,
The control unit closes the second valve in the normal operation and the refrigerant storage mode, and opens the chiller in the heat exchange mode. According to claim 2,
Further comprising a third valve that is opened and closed in the refrigerant storage pipe,
The control unit opens the third valve in the refrigerant storage mode and closes in the normal operation and the heat exchange mode. According to claim 2,
A receiver inlet pipe having one end connected to a refrigerant pipe between the condenser and the main expansion mechanism, and the other end connected to the receiver;
Further comprising a fourth valve that is opened and closed in the receiver inlet pipe,
The control unit opens the fourth valve in the heat exchange mode, and closes the chiller in the normal operation and the refrigerant storage mode.

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