KR102160283B1 - Automatic refrigerant rechargeable heat pump system and control method of the same - Google Patents

Abstract

In the present invention, when the superheat degree of the refrigerant is outside the preset optimum superheat degree range while operating the heat pump system, the refrigerant is automatically charged from the refrigerant charging tank to the suction side of the compressor, or the refrigerant charging tank from the discharge side of the condenser. Since the furnace can automatically discharge the refrigerant, the superheat degree of the refrigerant can be maintained in the optimum superheat degree range. In addition, refrigerant charging or refrigerant discharge is performed according to the superheat only when the temperature of the load circulating water and the temperature of the heat source circulating water are within a preset temperature range, thereby solving the increase or decrease in superheat due to insufficient refrigerant or overcharging. I can. In addition, by monitoring the weight of the refrigerant charging tank, it is possible to distinguish an increase in overheating due to leakage of the refrigerant in the heat pump system, and when the refrigerant leaks, a leakage alarm can be generated and the system can be stopped.

Description

Automatic refrigerant rechargeable heat pump system and control method of the same}

The present invention relates to a heat pump system capable of automatic refrigerant charging and a control method thereof. More specifically, an automatic refrigerant amount circulating during operation of the system is automatically maintained at an optimum amount to prevent shortage or overcharge of refrigerant. It relates to a heat pump system capable of charging a refrigerant and a control method thereof.

In general, the heat pump system includes a compressor, an evaporator, an expansion valve and a condenser. When the amount of refrigerant is insufficient in the heat pump system, the performance of the system is degraded, and when the refrigerant is severely insufficient, there is a risk of damage.

Conventionally, when the temperature of the refrigerant exceeds a preset range during normal operation of the heat pump system, it is determined that there is a leakage of the refrigerant.

However, in the related art, there is a limitation in that the leakage of the refrigerant can be determined only when the leakage amount of the refrigerant is excessively large. In addition, when the amount of refrigerant is insufficient, since the expansion valve is automatically controlled for normal operation of the system, the temperature of the refrigerant does not exceed a set range, and thus leakage of the refrigerant cannot be determined.

Korean Patent Publication 10-2007-0013826

An object of the present invention is to provide a heat pump system capable of automatic refrigerant charging and a control method thereof capable of preventing shortage or overcharging of refrigerant.

The heat pump system capable of automatically refrigerant charging according to the present invention is a heat pump system including a compressor, a four-way valve, an expansion valve, a load heat exchanger that serves as a condenser during heating operation, and a heat source heat exchanger that serves as a condenser during cooling operation. , A load temperature sensor measuring the temperature of the load circulating water flowing into the load heat exchanger, a heat source temperature sensor measuring the temperature of the heat source circulating water flowing into the heat source heat exchanger, and measuring the evaporation pressure of the refrigerant sucked into the compressor Refrigerant charging in which the evaporation pressure sensor to measure the evaporation temperature of the refrigerant sucked into the compressor, the refrigerant to be supplied to the suction flow path of the compressor is stored, and the refrigerant discharged from the discharge side of the condenser is stored A refrigerant charging channel configured to supply the refrigerant stored in the refrigerant charging tank to the suction channel of the compressor when the refrigerant is charged during the cooling operation or the heating operation by connecting the tank, the refrigerant charging tank and the suction flow path of the compressor, For cooling formed to be branched from a flow path connecting the heat source heat exchanger and the expansion valve to be connected to the refrigerant charging tank to discharge at least a part of the refrigerant discharged from the heat source heat exchanger to the refrigerant charging tank during cooling operation and when the refrigerant is discharged Branched from a refrigerant discharge flow path and a flow path connecting the load heat exchanger and the expansion valve and connected to the refrigerant charging tank, at least a portion of the refrigerant discharged from the load heat exchanger during heating operation and discharging the refrigerant is transferred to the refrigerant charging tank. A heating refrigerant discharge passage formed to discharge, a refrigerant charging valve installed in the refrigerant charging passage, a cooling refrigerant discharge valve installed in the cooling refrigerant discharge passage, a heating refrigerant discharge valve installed in the heating refrigerant discharge passage, and the evaporation Calculate the superheat degree of the refrigerant at the suction side of the compressor according to the values measured by the pressure sensor and the evaporation temperature sensor, the temperature of the load circulating water measured by the load temperature sensor, and the heat source circulating water measured by the heat source temperature sensor. Temperature, depending on the superheat of the refrigerant And a control unit configured to determine the refrigerant charging or discharging the refrigerant and controlling the opening degrees of the refrigerant charging valve, the cooling refrigerant discharge valve, and the heating refrigerant discharge valve.

In the cooling operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset cooling set temperature range, and the superheat degree of the refrigerant is If the first superheat set in advance is equal to or higher than the upper limit, the refrigerant charging valve is opened for a preset charging time, and the cooling refrigerant discharge valve and the heating refrigerant discharge valve are blocked, so that the refrigerant stored in the refrigerant charging tank is transferred to the compressor. Fill it with the suction channel.

When the charging time elapses, the control unit closes the refrigerant charging valve, and when the superheat degree of the refrigerant is equal to or greater than the second superheat degree upper limit value set lower than the first superheat degree upper limit value after the preset operation time elapses, the The refrigerant charging valve is opened again during the charging time to recharge the refrigerant.

When the cooling operation is performed, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset cooling set temperature range, and the superheat degree of the refrigerant If the first superheat set in advance is less than the lower limit, the cooling refrigerant discharge valve is opened for a preset discharge time, and the refrigerant charging valve and the heating refrigerant discharge valve are shielded, so that at least a portion of the refrigerant from the heat source heat exchanger Is discharged to the refrigerant charging tank.

When the discharge time elapses, the control unit closes the cooling refrigerant discharge valve, and after a predetermined operation time elapses, the superheat degree of the refrigerant is set higher than the first superheat lower limit value by a predetermined value. 2 If the superheat is also less than the lower limit, the cooling refrigerant discharge valve is opened again during the discharge time to re-discharge the refrigerant.

The control unit, during the heating operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset heating set temperature range, and the superheat degree of the refrigerant If the first superheat set in advance is equal to or greater than the upper limit, the refrigerant charging valve is opened for a preset charging time, and the cooling refrigerant discharge valve and the heating refrigerant discharge valve are closed.

When the charging time has elapsed, the control unit closes the refrigerant charging valve, and after the predetermined operation time has elapsed, the control unit may be configured to provide a second superheat degree lower than the first superheat degree upper limit value or higher. , The refrigerant charging valve is opened again during the charging time to recharge the refrigerant.

The control unit, during the heating operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset heating set temperature range, and the superheat degree of the refrigerant If the predetermined first superheat is also less than or equal to the lower limit, the heating refrigerant discharge valve is opened for a preset discharge time, and the refrigerant charging valve and the cooling refrigerant discharge valve are shielded, so that at least some of the refrigerant discharged from the load heat exchanger is removed. Discharge to the refrigerant filling tank.

When the discharge time elapses, the control unit closes the heating refrigerant discharge valve, and after a preset operation time elapses, the second superheat degree of the refrigerant is set higher by a predetermined value than the first superheat lower limit value. If the superheat is also equal to or less than the lower limit, the heating refrigerant discharge valve is opened again during the discharge time to re-discharge the refrigerant.

A refrigerant weight sensor installed in the refrigerant charging tank to measure the weight of the refrigerant stored in the refrigerant charging tank, wherein the control unit comprises: a refrigerant when the weight of the refrigerant measured by the refrigerant weight sensor is equal to or greater than a preset weight Determine charging or refrigerant discharge.

Further comprising a leakage alarm device notifying the leakage of the refrigerant, wherein the control unit, when the weight of the refrigerant measured by the refrigerant weight sensor is less than the set weight and the weight of the refrigerant is more than a preset minimum value, the leakage alarm device Works.

When the weight of the refrigerant measured by the refrigerant weight sensor is less than the minimum value, the control unit operates the leakage warning device and stops the operation of the heat pump system.

A heat pump system capable of automatic refrigerant charging according to another aspect of the present invention includes a compressor, a four-way valve, an expansion valve, a load heat exchanger serving as a condenser during heating operation, and a heat source heat exchanger serving as a condenser during cooling operation. In the system, a load temperature sensor for measuring the temperature of the load circulating water flowing into the load heat exchanger, a heat source temperature sensor for measuring the temperature of the heat source circulating water flowing into the heat source heat exchanger, and evaporation of the refrigerant sucked into the compressor An evaporation pressure sensor that measures pressure, an evaporation temperature sensor that measures the evaporation temperature of the refrigerant sucked into the compressor, and a refrigerant for supplying to the suction passage of the compressor are stored, and the refrigerant discharged from the discharge side of the condenser is stored. A refrigerant charging channel configured to supply the refrigerant stored in the refrigerant charging tank to the suction channel of the compressor during cooling or heating operation by connecting the refrigerant charging tank to the refrigerant charging tank and the suction flow path of the compressor; For cooling formed to be branched from a flow path connecting the heat source heat exchanger and the expansion valve to be connected to the refrigerant charging tank to discharge at least a part of the refrigerant discharged from the heat source heat exchanger to the refrigerant charging tank during cooling operation and when the refrigerant is discharged Branched from a refrigerant discharge flow path and a flow path connecting the load heat exchanger and the expansion valve and connected to the refrigerant charging tank, at least a portion of the refrigerant discharged from the load heat exchanger during heating operation and discharging the refrigerant is transferred to the refrigerant charging tank. A heating refrigerant discharge passage formed to discharge, a refrigerant charging valve installed in the refrigerant charging passage, a cooling refrigerant discharge valve installed in the cooling refrigerant discharge passage, a heating refrigerant discharge valve installed in the heating refrigerant discharge passage, and the refrigerant A refrigerant weight sensor installed in the charging tank to measure the weight of the refrigerant stored in the refrigerant charging tank, a leakage alarm device notifying the leakage of the refrigerant, and the weight of the refrigerant measured by the refrigerant weight sensor is equal to or greater than a preset set weight If, the load temperature The temperature of the load circulating water measured by the sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are compared with a preset temperature range, and the superheat degree of the suction side refrigerant of the compressor is compared with a preset superheat upper limit value and a preset And a control unit for controlling an opening degree of the refrigerant charging valve, the cooling refrigerant discharge valve, and the heating refrigerant discharge valve, compared with the superheat lower limit value.

The control method of a heat pump system capable of automatic refrigerant charging according to the present invention includes a weight comparison step of comparing a weight of a refrigerant stored in a refrigerant charging tank with a preset weight; A temperature comparison step of comparing a temperature of the load circulating water flowing into the load heat exchanger and a temperature of the heat source circulating water flowing into the heat source heat exchanger with a preset set temperature range when the weight of the refrigerant is greater than the set weight; If the temperature of the load circulating water and the temperature of the heat source circulating water are within the set temperature range, a superheat degree comparison step of comparing the superheat degree of the suction side refrigerant of the compressor with a preset first superheat upper limit value and a first superheat lower limit value Wow; When the superheat of the refrigerant is greater than or equal to the first superheat upper limit, the refrigerant charging valve installed in the refrigerant charging passage connecting the refrigerant charging tank and the suction passage of the compressor is opened for a preset charging time, and the refrigerant charging tank is A refrigerant charging step of charging a refrigerant into the suction passage of the compressor; When the superheat of the refrigerant is less than the first superheat lower limit, the refrigerant discharge valve installed in the refrigerant discharge passage connecting the refrigerant charging tank and the discharge passage of the condenser is opened for a preset discharge time, and from the discharge passage of the condenser. And discharging the refrigerant to the refrigerant charging tank.

When the charging time has elapsed, the refrigerant charging valve is closed, and if the superheat of the refrigerant is equal to or greater than the second superheating upper limit value set lower than the first superheating upper limit value after the preset operation time has elapsed, the refrigerant charging valve is closed. It further includes a recharging step of recharging the refrigerant by opening again during the charging time.

When the discharge time elapses, the refrigerant discharge valve is closed, and after the predetermined operation time elapses, if the superheat of the refrigerant is higher than the first superheat lower limit by a predetermined value and is less than or equal to the second superheat lower limit value And a re-discharging step of re-discharging the refrigerant by opening the refrigerant discharging valve again during the discharging time.

When the weight of the refrigerant is less than the set weight and is more than a preset minimum value, a refrigerant leakage is displayed, and when the weight of the refrigerant is less than the set weight and less than the minimum value, a refrigerant leakage is displayed and the heat pump system operates. Stop.

In the present invention, when the superheat degree of the refrigerant is outside the preset optimum superheat degree range while operating the heat pump system, the refrigerant is automatically charged from the refrigerant charging tank to the suction side of the compressor, or the refrigerant charging tank from the discharge side of the condenser. Since the furnace can automatically discharge the refrigerant, the superheat degree of the refrigerant can be maintained in the optimum superheat degree range.

In addition, refrigerant charging or refrigerant discharge is performed according to the superheat only when the temperature of the load circulating water and the temperature of the heat source circulating water are within a preset temperature range, thereby solving the increase or decrease in superheat due to insufficient refrigerant or overcharging. I can.

In addition, by monitoring the weight of the refrigerant charging tank, it is possible to distinguish an increase in overheating due to leakage of the refrigerant in the heat pump system, and when the refrigerant leaks, a leakage alarm can be generated and the system can be stopped.

1 is a view showing charging of a refrigerant during cooling operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.
2 is a view showing refrigerant discharge during a cooling operation of a heat pump system capable of automatic refrigerant charging according to an embodiment of the present invention.
3 is a view showing charging of a refrigerant during a heating operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.
4 is a view showing refrigerant discharge during a heating operation of a heat pump system capable of automatic refrigerant charging according to an embodiment of the present invention.
5 is a flowchart illustrating a control method during cooling operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.
6 is a flowchart illustrating a control method during heating operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a view showing charging of a refrigerant during cooling operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention. 2 is a view showing refrigerant discharge during a cooling operation of a heat pump system capable of automatic refrigerant charging according to an embodiment of the present invention. 3 is a view showing charging of a refrigerant during a heating operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention. 4 is a view showing refrigerant discharge during a heating operation of a heat pump system capable of automatic refrigerant charging according to an embodiment of the present invention.

1 to 4, a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention includes a compressor 10, a load heat exchanger 20, a heat source heat exchanger 30, and an expansion valve 40. , A four-way valve 50, a refrigerant charging tank 60, a refrigerant flow path and a control unit (not shown).

The load heat exchanger 20 is a heat exchanger for exchanging heat between the refrigerant circulating in the heat pump system and the load circulating water. The load heat exchanger 20 serves as a condenser for condensing the refrigerant during heating operation and serves as an evaporator for evaporating the refrigerant during cooling operation. The load circulating water is a heat medium that absorbs heat from the refrigerant or takes heat from the refrigerant to transfer heat to the cooling/heating load side.

A load heat exchanger suction passage 201 through which load circulating water is introduced is connected to the suction side of the load heat exchanger 20, and a load heat exchanger discharge passage 202 through which load circulating water is discharged to the discharge side of the load heat exchanger 20 Is connected.

A first temperature sensor 81 is installed in the suction passage 201 of the load heat exchanger. Hereinafter, the first temperature sensor 81 is referred to as a load temperature sensor 81 that measures the temperature of the load circulating water flowing into the load heat exchanger 20.

A second temperature sensor 82 is installed in the load heat exchanger discharge passage 202. The second temperature sensor 82 measures the temperature of the load circulating water discharged from the load heat exchanger 20.

The heat source heat exchanger 30 is a heat exchanger for exchanging heat between the refrigerant circulating in the heat pump system and the heat source circulating water. The heat source heat exchanger 30 serves as an evaporator for evaporating the refrigerant during a heating operation, and serves as a condenser for condensing the refrigerant during a cooling operation.

A heat source heat exchanger suction passage 203 through which heat source circulating water is introduced is connected to the suction side of the heat source heat exchanger 30, and a heat source heat exchanger discharge passage 204 through which heat source circulated water is discharged to the discharge side of the heat source heat exchanger 30 Is connected.

A third temperature sensor 82 is installed in the heat source heat exchanger suction passage 203. Hereinafter, the third temperature sensor 83 is referred to as a heat source temperature sensor 83 that measures the temperature of the heat source circulating water flowing into the heat source heat exchanger 30.

A fourth temperature sensor 84 is installed in the heat source heat exchanger discharge passage 204. The fourth temperature sensor 84 measures the temperature of the heat source circulating water discharged from the heat source heat exchanger 30.

The refrigerant flow path includes a suction flow path 11 of the compressor 10, a discharge flow path 12 of the compressor 10, a first refrigerant flow path 21, a second refrigerant flow path 22, and a third refrigerant flow path ( 23), and a fourth refrigerant passage 24.

A fifth temperature sensor 85 for measuring the temperature of the refrigerant discharged from the compressor 10 is installed in the discharge passage 12 of the compressor 10.

A sixth temperature sensor 86 that measures the temperature of the refrigerant sucked into the compressor 10 is installed in the suction passage 11 of the compressor 10. Hereinafter, the sixth temperature sensor 86 is referred to as an evaporation temperature sensor 86 that measures the evaporation temperature of the refrigerant sucked into the compressor 10.

In addition, an evaporation pressure sensor 87 is installed in the suction passage 11 of the compressor 10 to measure the evaporation pressure of the refrigerant sucked into the compressor 10.

The first refrigerant passage 21 is a passage connecting the four-way valve 50 and the load heat exchanger 20.

The second refrigerant passage 22 is a passage connecting the load heat exchanger 20 and the expansion valve 40.

The third refrigerant flow path 23 is a flow path connecting the expansion valve 40 and the heat source heat exchanger 30.

The fourth refrigerant flow path 24 is a flow path connecting the heat source heat exchanger 30 and the four-way valve 50.

The refrigerant charging tank 60 is connected to the suction side of the compressor 10 and the discharge side of the condenser, and supplies the refrigerant stored therein to the suction side of the compressor 10 or the refrigerant discharged from the discharge side of the condenser. Save it.

The refrigerant charging flow path 61 is connected to the discharge port of the refrigerant charging tank 60.

The refrigerant charging passage 61 connects the discharge port of the refrigerant charging tank 60 and the suction passage 11 of the compressor 10 to transfer the refrigerant stored in the refrigerant charging tank 60 to the compressor. It is formed to supply to the suction flow path 11 of (10).

A refrigerant charging valve 101 is installed in the refrigerant charging passage 61. The refrigerant charging valve 101 is a solenoid valve whose opening rate is controlled under control of the controller (not shown). The refrigerant charging valve 101 is used when refrigerant is filled regardless of cooling operation and heating operation.

A first check valve 91 is installed in the refrigerant charging passage 61.

A refrigerant discharge passage for discharging the refrigerant from the condenser and guiding the refrigerant to the refrigerant charging tank 60 is connected to the suction side of the refrigerant charging tank 60. Since the refrigerant must be discharged from the high-pressure side, the refrigerant discharge passage is connected to the discharge side of the condenser.

The refrigerant discharge passage includes a cooling refrigerant discharge passage 71 and a heating refrigerant discharge passage 72.

The cooling refrigerant discharge passage 71 is branched from the third refrigerant passage 23 connecting the heat source heat exchanger 30 and the expansion valve 40 to a suction passage of the refrigerant charging tank 60. Connected. The cooling refrigerant discharge passage 71 is a passage for guiding to discharge at least some of the refrigerant discharged from the heat source heat exchanger 30 to the refrigerant charging tank 60 during cooling operation and when the refrigerant is discharged.

A cooling refrigerant discharge valve 103 is installed in the cooling refrigerant discharge passage 71. The cooling refrigerant discharge valve 103 is a solenoid valve whose opening rate is controlled under the control of the controller (not shown). The cooling refrigerant discharge valve 103 is used only during cooling operation.

The heating refrigerant discharge passage 72 is branched from the second refrigerant passage 22 connecting the load heat exchanger 20 and the expansion valve 40 and is connected to the suction passage of the refrigerant charging tank 60. . The heating refrigerant discharge passage 72 is a passage for guiding to discharge at least a part of the refrigerant discharged from the load heat exchanger 20 to the refrigerant charging tank 60 during heating operation and when the refrigerant is discharged.

A heating refrigerant discharge valve 102 is installed in the heating refrigerant discharge passage 72. The heating refrigerant discharge valve 102 is a solenoid valve whose opening rate is controlled under control of the controller (not shown). The heating refrigerant discharge valve 102 is used only during heating operation.

A second check valve 92 is installed in the suction passage of the refrigerant charging tank 60.

In addition, a refrigerant weight sensor 88 is installed in the refrigerant charging tank 60.

The refrigerant weight sensor 88 is a sensor installed below the refrigerant charging tank 60 to measure the weight of the refrigerant stored in the refrigerant charging tank 60. When the weight of the empty refrigerant charging tank 60 is set as the origin, the weight of the refrigerant stored in the refrigerant charging tank 60 can be measured.

The control unit (not shown) calculates the superheat degree of the refrigerant at the suction side of the compressor 10 according to the evaporation pressure measured by the evaporation pressure sensor 87 and the evaporation temperature measured by the evaporation temperature sensor 86. .

In addition, the controller (not shown) compares the temperature of the load circulating water measured by the load temperature sensor 81 and the temperature of the heat source circulating water measured by the heat source temperature sensor 83 with a preset temperature range. . Here, the set temperature range is set differently according to the cooling operation and the heating operation.

The control unit (not shown) determines whether refrigerant charging or discharging is necessary according to the temperature of the load circulating water, the temperature of the heat source circulating water, and the superheat degree of the refrigerant, and the refrigerant charging valve 101 , Controls the opening degrees of the heating refrigerant discharge valve 102 and the cooling refrigerant discharge valve 103.

In addition, the heat pump system further includes a leakage warning device (not shown) for notifying leakage of the refrigerant. The leakage alarm device may generate an alarm sound or transmit an alarm message to an administrator or a terminal of a management office.

The operation and control method of the heat pump system capable of automatic refrigerant charging according to an embodiment of the present invention configured as described above will be described as follows.

First, refrigerant charging or refrigerant discharge during cooling operation will be described.

5 is a flowchart illustrating a control method during cooling operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.

5, the controller (not shown) starts the compressor 10 (S11).

After starting the compressor 10, it is determined whether a preset time has elapsed. (S12)

Here, the setting time is described as an example as about 5 minutes.

When the 5 minutes elapse, a weight comparison step of comparing the weight of the refrigerant measured by the refrigerant weight sensor 88 with a preset weight is performed. (S13)

Here, the set weight is described as an example as about 3 kg.

When the weight of the refrigerant is greater than or equal to the set weight in the weight comparison step, a temperature comparison step of comparing the temperature of the load circulating water and the temperature of the heat source circulating water with the set temperature range is performed. (S14)

Here, the set temperature range is set differently according to the cooling operation and the heating operation. In the cooling setting temperature range set during the cooling operation, the temperature of the load circulating water is 15 to 35°C, and the temperature of the heat source circulating water is 12 to 15°C.

In the temperature comparison step, if the temperature of the load circulating water is within the range of 15 to 35°C and the temperature of the heat source circulating water is within the range of 12 to 15°C, the temperature of the load circulating water or the temperature of the heat source circulating water is system safety. Since it is an operating condition range, it can be determined that there is no change in superheat degree according to the load or heat source.

Accordingly, when the temperature of the load circulating water and the temperature of the heat source circulating water are within the cooling set temperature range, the superheat degree of the suction side refrigerant of the compressor 10 is compared with a preset first superheat degree upper limit value. Perform the step (S15)

Here, the first superheat upper limit is described as an example of about 6K.

When the superheat of the refrigerant is equal to or greater than the first superheat upper limit, it may be determined that the amount of refrigerant circulating through the heat pump system is insufficient.

The control unit (not shown) opens the refrigerant charging valve 101 for a preset charging time, and supplies the refrigerant stored in the refrigerant charging tank 60 to the suction passage 11 of the compressor 10 Charge the (S16)

Here, the charging time is described as an example as about 2 seconds.

The opening rate of the refrigerant charging valve 101 may be preset differently according to the superheat degree.

At this time, the control unit (not shown) shields the heating refrigerant discharge valve 102 and the cooling refrigerant discharge valve 103.

When the charging time elapses, the refrigerant charging valve 101 is closed.

Thereafter, while maintaining the operation of the heat pump system, it is determined whether or not a preset operation time has elapsed (S17).

Here, the operation time is described as an example as about 60 seconds.

When the operation time elapses, the superheat degree of the suction side refrigerant of the compressor 10 is recalculated, and the superheat degree of the refrigerant is compared with a second superheat degree upper limit set lower by a predetermined value than the first superheat upper limit value. . (S18)

Here, the upper limit of the second superheat is described as an example of about 5K.

If the superheat of the refrigerant is equal to or greater than the second superheat upper limit, the control unit (not shown) determines that the superheat has not been sufficiently lowered, and opens the refrigerant charging valve 101 again during the charging time to release the refrigerant. Recharge.

On the other hand, if the superheat of the refrigerant is less than the upper limit of the second superheat, the temperature comparison step (S14) may be performed again.

On the other hand, if the weight of the refrigerant is less than the set weight in the weight comparison step (S13), the weight of the refrigerant is compared with a minimum value set lower than the set weight (S23)

When the weight of the refrigerant is more than the minimum value, the leakage alarm device (not shown) is operated to notify the leakage of the refrigerant (S24).

When the weight of the refrigerant is less than the minimum value, the leakage alarm device (not shown) is operated to notify the leakage of the refrigerant (S25), and the operation of the heat pump system is stopped (S26).

Therefore, it is possible to check whether the refrigerant leaks according to the amount of refrigerant stored in the refrigerant charging tank 60, and if the weight of the refrigerant is less than the minimum value, it is determined that the refrigerant leakage is serious and the operation of the heat pump system is stopped. I can make it.

On the other hand, in the temperature comparison step (S14), if the temperature of the load circulating water is within the range of 15 to 35°C, and the temperature of the heat source circulating water is out of the range of 12 to 15°C, the temperature of the load circulating water or the heat source circulating water It is determined that the superheat degree is not stable because the temperature of is out of the range of the safe operating conditions of the system for cooling operation, and the refrigerant is not charged and discharged.

Meanwhile, if the superheat degree of the refrigerant is less than the first superheat upper limit value in the superheat comparison step (S15), the superheat degree of the refrigerant is compared with a preset first superheat lower limit value (S19).

When the superheat of the refrigerant is less than or equal to the first superheat lower limit, it is determined that the amount of refrigerant circulating through the heat pump system is excessive.

Accordingly, the control unit (not shown) opens the cooling refrigerant discharge valve 103 for a preset discharge time, and transfers at least a portion of the refrigerant discharged from the heat source heat exchanger 30 to the expansion valve 40. It is discharged to the refrigerant charging tank 60 before it is introduced (S20).

During cooling operation, since the heat source heat exchanger 30 serves as a condenser, the refrigerant discharged from the heat source heat exchanger 30 is discharged.

Here, the release time is described as an example as about 2 seconds.

The opening rate of the cooling refrigerant discharge valve 103 may be preset differently according to the superheat degree or controllable according to the superheat degree.

At this time, the control unit (not shown) shields the refrigerant charging valve 101 and the heating refrigerant discharge valve 102.

When the discharge time elapses, the cooling refrigerant discharge valve 103 is closed.

Thereafter, while maintaining the operation of the heat pump system, it is determined whether the operation time has elapsed (S21).

When the operation time elapses, the superheat degree of the suction-side refrigerant of the compressor 10 is recalculated, and the superheat degree of the refrigerant is compared with a second superheat lower limit value set higher than the first superheat lower limit value by a predetermined value. .(S22)

Here, the second superheat lower limit is described as an example as about 3K.

The control unit (not shown) determines that the superheat degree is not sufficiently high when the superheat degree of the refrigerant is less than the second superheat lower limit value, and opens the cooling refrigerant discharge valve 103 again during the discharge time. Re-discharge the refrigerant.

Thereafter, when the superheat degree of the refrigerant becomes higher than the second superheat degree lower limit value, the discharge of the refrigerant may be stopped and the temperature comparison step (S14) may be performed again.

Meanwhile, FIG. 6 is a flow chart showing a control method during heating operation of a heat pump system capable of automatically charging a refrigerant according to an embodiment of the present invention.

With reference to FIG. 6, charging of the refrigerant and discharge of the refrigerant during the heating operation will be described.

First, the control unit (not shown) starts the compressor 10 (S31).

After starting the compressor 10, it is determined whether a preset set time has elapsed (S32).

Here, the setting time is described as an example as about 5 minutes.

When the 5 minutes elapse, a weight comparison step of comparing the weight of the refrigerant measured by the refrigerant weight sensor 88 with the set weight is performed (S33).

Here, the set weight is described as an example as about 3 kg.

If the weight of the refrigerant is greater than or equal to the set weight in the weight comparison step, a temperature comparison step of comparing the temperature of the load circulating water and the temperature of the heat source circulating water with the set temperature range is performed (S34).

Here, the set temperature range is set differently according to the cooling operation and the heating operation. In the heating setting temperature range, the temperature of the load circulating water is 5 to 15°C, and the temperature of the heat source circulating water is 40 to 45°C.

In the temperature comparison step, if the temperature of the load circulating water is within the range of 5 to 15°C and the temperature of the heat source circulating water is within the range of 40 to 45°C, the temperature of the load circulating water or the temperature of the heat source circulating water is Since it is the range of the safe operating conditions of the system, it can be determined that there is no change in the superheat degree according to the load or heat source.

Accordingly, when the temperature of the load circulating water and the temperature of the heat source circulating water are within the heating set temperature range, a superheat degree comparison step of comparing the superheat degree of the suction side refrigerant of the compressor 10 with the first superheat degree upper limit value. Performs. (S35)

If the superheat of the refrigerant is equal to or greater than the first superheat upper limit, it may be determined that the amount of refrigerant circulating through the heat pump system is insufficient.

The control unit (not shown) opens the refrigerant charging valve 101 for a preset charging time, and supplies the refrigerant stored in the refrigerant charging tank 60 to the suction passage 11 of the compressor 10 Charge the (S36)

The opening rate of the refrigerant charging valve 101 may be preset differently according to the superheat degree or may be controlled according to the superheat degree.

At this time, the control unit (not shown) shields the heating refrigerant discharge valve 102 and the cooling refrigerant discharge valve 103.

When the charging time elapses, the refrigerant charging valve 101 is closed.

Thereafter, while maintaining the operation of the heat pump system, it is determined whether the operation time has elapsed (S37).

When the operation time elapses, the superheat degree of the suction side refrigerant of the compressor 10 is recalculated, and the superheat degree of the refrigerant is compared with a second superheat degree upper limit set lower by a predetermined value than the first superheat upper limit value. .(S38)

If the superheat of the refrigerant is equal to or greater than the second superheat upper limit, the control unit (not shown) determines that the superheat has not been sufficiently lowered, and opens the refrigerant charging valve 101 again during the charging time to release the refrigerant. Recharge.

If the superheat degree of the refrigerant is less than the upper limit of the second superheat degree, it is determined that the superheat degree of the refrigerant is sufficiently lowered, so that charging of the refrigerant is stopped, and the temperature comparison step (S14) may be performed again.

On the other hand, when the weight of the refrigerant is less than the set weight in the weight comparison step (S13), the weight of the refrigerant is compared with a minimum value set lower than the set weight (S43)

If the weight of the refrigerant is more than the minimum value, the leakage alarm device (not shown) is operated to notify the leakage of the refrigerant (S44).

When the weight of the refrigerant is less than the minimum value, the leakage alarm device (not shown) is operated to notify the leakage of the refrigerant (S45), and the operation of the heat pump system is stopped (S46).

Therefore, it is possible to check whether the refrigerant leaks according to the amount of refrigerant stored in the refrigerant charging tank 60, and if the weight of the refrigerant is less than the minimum value, it is determined that the refrigerant leakage is serious, and charging and discharging of the refrigerant are not performed. Does not.

On the other hand, in the temperature comparison step (S14), when the temperature of the load circulating water is within the range of 5 to 15°C, and the temperature of the heat source circulating water is out of the range of 40 to 45°C, the temperature of the load circulating water or the heat source circulating water It is determined that the temperature of is out of the range of the safe operation condition of the system for heating operation, and the operation of the heat pump system may be stopped (S46).

Meanwhile, if the superheat degree of the refrigerant is less than the first superheat upper limit value in the superheat comparison step S35, the superheat degree of the refrigerant is compared with a preset first superheat lower limit value (S39).

When the superheat of the refrigerant is less than or equal to the first superheat lower limit, it is determined that the amount of refrigerant circulating through the heat pump system is excessive.

Accordingly, the control unit (not shown) opens the heating refrigerant discharge valve 102 for the discharge time, so that at least a portion of the refrigerant discharged from the load heat exchanger 20 flows into the expansion valve 40. Previously, it is discharged to the refrigerant charging tank 60 (S40).

During the heating operation, since the load heat exchanger 20 functions as a condenser, the refrigerant discharged from the load heat exchanger 20 is discharged.

The opening rate of the heating refrigerant discharge valve 102 may be preset differently according to the superheat degree or controllable according to the superheat degree.

At this time, the control unit (not shown) shields the refrigerant charging valve 101 and the cooling refrigerant discharge valve 103.

When the discharge time elapses, the heating refrigerant discharge valve 102 is closed.

Thereafter, while maintaining the operation of the heat pump system, it is determined whether the operation time has elapsed (S41).

When the operation time elapses, the superheat degree of the suction-side refrigerant of the compressor 10 is recalculated, and the superheat degree of the refrigerant is compared with a second superheat lower limit value set higher than the first superheat lower limit value by a predetermined value. .(S42)

Here, the second superheat lower limit is described as an example as about 3K.

If the superheat of the refrigerant is less than the second superheat lower limit, the control unit (not shown) determines that the superheat has not sufficiently increased, and opens the heating refrigerant discharge valve 102 again for the discharge time. Re-release.

Thereafter, when the superheat degree of the refrigerant becomes higher than the second superheat degree lower limit value, the discharge of the refrigerant may be stopped and the temperature comparison step (S14) may be performed again.

As described above, in the embodiment of the present invention, when the superheat degree of the refrigerant is out of a preset optimum superheat degree range while operating the heat pump system, the refrigerant is automatically charged from the refrigerant charging tank to the suction side of the compressor. Alternatively, since the refrigerant may be discharged from the discharge side of the condenser to the refrigerant charging tank, the superheat degree of the refrigerant can be maintained within the optimum superheat degree range.

Accordingly, it is possible to prevent system failure or damage due to a shortage of refrigerant and prevent overcharging of the refrigerant.

In addition, by monitoring the weight of the refrigerant charging tank 60, it is possible to distinguish an increase in the degree of overheating due to leakage of the refrigerant in the heat pump system, and to generate a leakage alarm and stop the system.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely exemplary, and those of ordinary skill in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

10: compressor 11: compressor suction passage
12: compressor discharge passage 20: load heat exchanger
30: heat source heat exchanger 40 expansion valve
50: four-way valve 60: refrigerant charging tank
61: refrigerant charging passage 71: cooling refrigerant discharge passage
72: refrigerant discharge flow path for heating 88: refrigerant weight sensor
101: refrigerant charging valve
102: refrigerant discharge valve for heating 103: refrigerant discharge valve for cooling

Claims (17)

In a heat pump system comprising a compressor, a four-way valve, an expansion valve, a load heat exchanger that serves as a condenser during heating operation, and a heat source heat exchanger that serves as a condenser during cooling operation,
A load temperature sensor for measuring the temperature of the load circulating water flowing into the load heat exchanger,
A heat source temperature sensor for measuring the temperature of the heat source circulating water flowing into the heat source heat exchanger,
An evaporation pressure sensor that measures the evaporation pressure of the refrigerant sucked into the compressor,
An evaporation temperature sensor for measuring the evaporation temperature of the refrigerant sucked into the compressor,
A refrigerant charging tank in which a refrigerant supplied to the suction passage of the compressor is stored, and a refrigerant discharged from a discharge side of the condenser is stored;
A refrigerant charging flow path formed to supply the refrigerant stored in the refrigerant charging tank to the suction flow path of the compressor during the cooling operation or the heating operation by connecting the refrigerant charging tank to the suction flow path of the compressor;
For cooling formed to be branched from a flow path connecting the heat source heat exchanger and the expansion valve to be connected to the refrigerant charging tank to discharge at least a part of the refrigerant discharged from the heat source heat exchanger to the refrigerant charging tank during cooling operation and when the refrigerant is discharged A refrigerant discharge passage,
A heating refrigerant formed to discharge at least a portion of the refrigerant discharged from the load heat exchanger to the refrigerant charging tank when a refrigerant is discharged during a heating operation and is branched from a flow path connecting the load heat exchanger and the expansion valve to With the discharge flow path,
A refrigerant charging valve installed in the refrigerant charging passage,
A cooling refrigerant discharge valve installed in the cooling refrigerant discharge passage;
A heating refrigerant discharge valve installed in the heating refrigerant discharge passage;
Calculate the superheat degree of the suction side refrigerant of the compressor according to the values measured by the evaporation pressure sensor and the evaporation temperature sensor, the temperature of the load circulating water measured by the load temperature sensor, and the heat source circulation measured by the heat source temperature sensor Automatic refrigerant charging is possible, including a control unit for controlling the opening degree of the refrigerant charging valve, the cooling refrigerant discharge valve, and the heating refrigerant discharge valve by determining refrigerant charging or refrigerant discharge according to the temperature of the water and the degree of superheat of the refrigerant. Heat pump system. The method according to claim 1,
The control unit,
During the cooling operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset cooling set temperature range,
If the superheat degree of the refrigerant is equal to or greater than the first superheat degree set in advance,
The refrigerant charging valve is opened for a preset charging time, and the cooling refrigerant discharge valve and the heating refrigerant discharge valve are closed,
A heat pump system capable of automatic refrigerant charging for charging the refrigerant stored in the refrigerant charging tank into the suction flow path of the compressor. The method according to claim 2,
The control unit,
When the charging time elapses, the refrigerant charging valve is closed, and after the lapse of a preset operation time, the superheat of the refrigerant is greater than or equal to the second superheat upper limit set lower than the first superheat upper limit,
A heat pump system capable of automatic refrigerant charging to recharge the refrigerant by opening the refrigerant charging valve again during the charging time. The method according to claim 1,
The control unit,
During the cooling operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset cooling set temperature range,
When the superheat degree of the refrigerant is less than or equal to the preset first superheat degree lower limit value, the cooling refrigerant discharge valve is opened for a preset discharge time, and the refrigerant charging valve and the heating refrigerant discharge valve are closed,
A heat pump system capable of automatic refrigerant charging for discharging at least some of the refrigerant from the heat source heat exchanger to the refrigerant charging tank. The method of claim 4,
The control unit,
When the discharge time elapses, the cooling refrigerant discharge valve is shielded, and after the preset operation time elapses, the second superheat lower limit value is set higher than the first superheat lower limit by a predetermined value. If less than,
A heat pump system capable of automatically refrigerant charging for re-discharging the refrigerant by opening the cooling refrigerant discharge valve again during the discharge time. The method according to claim 1,
The control unit,
During the heating operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset heating set temperature range,
When the superheat of the refrigerant is equal to or greater than the first superheat upper limit set in advance, the refrigerant charging valve is opened for a preset charging time, and the cooling refrigerant discharge valve and the heating refrigerant discharge valve are shielded. Pump system. The method of claim 6,
The control unit,
When the charging time has elapsed, the refrigerant charging valve is closed, and after the predetermined operation time has elapsed, the superheat of the refrigerant is greater than or equal to the upper limit of the second superheat set lower than the upper limit of the first superheat,
A heat pump system capable of automatic refrigerant charging to recharge the refrigerant by opening the refrigerant charging valve again during the charging time. The method according to claim 1,
The control unit,
During the heating operation, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are within a preset heating set temperature range,
When the superheat degree of the refrigerant is less than or equal to the preset first superheat degree lower limit value, the heating refrigerant discharge valve is opened for a preset discharge time, and the refrigerant charging valve and the cooling refrigerant discharge valve are closed,
A heat pump system capable of automatic refrigerant charging for discharging at least a portion of the refrigerant from the load heat exchanger to the refrigerant charging tank. The method of claim 8,
The control unit,
When the discharge time elapses, the heating refrigerant discharge valve is closed, and after a preset operation time elapses, the superheat degree of the refrigerant is higher than the first superheat degree lower limit by a predetermined value and is equal to or less than the second superheat lower limit value. If,
A heat pump system capable of automatically refrigerant charging for re-discharging the refrigerant by opening the heating refrigerant discharge valve again during the discharge time. The method according to claim 1,
It is installed in the refrigerant charging tank, further comprising a refrigerant weight sensor for measuring the weight of the refrigerant stored in the refrigerant charging tank,
The control unit, when the weight of the refrigerant measured by the refrigerant weight sensor is equal to or greater than a preset weight, the heat pump system capable of automatically refrigerant charging to determine refrigerant charging or refrigerant discharge. The method of claim 10,
Further comprising a leakage alarm device notifying the leakage of the refrigerant,
The control unit,
If the weight of the refrigerant measured by the refrigerant weight sensor is less than the set weight and the weight of the refrigerant is more than a preset minimum value,
A heat pump system capable of automatically charging refrigerant to operate the leak alarm device. The method of claim 11,
The control unit,
If the weight of the refrigerant measured by the refrigerant weight sensor is less than the minimum value,
A heat pump system capable of automatically charging a refrigerant to operate the leakage warning device and stop the operation of the heat pump system. In a heat pump system comprising a compressor, a four-way valve, an expansion valve, a load heat exchanger that serves as a condenser during heating operation, and a heat source heat exchanger that serves as a condenser during cooling operation,
A load temperature sensor for measuring the temperature of the load circulating water flowing into the load heat exchanger,
A heat source temperature sensor for measuring the temperature of the heat source circulating water flowing into the heat source heat exchanger,
An evaporation pressure sensor that measures the evaporation pressure of the refrigerant sucked into the compressor,
An evaporation temperature sensor for measuring the evaporation temperature of the refrigerant sucked into the compressor,
A refrigerant charging tank in which a refrigerant supplied to the suction passage of the compressor is stored, and a refrigerant discharged from a discharge side of the condenser is stored;
A refrigerant charging flow path formed to supply the refrigerant stored in the refrigerant charging tank to the suction flow path of the compressor during cooling or heating operation by connecting the refrigerant charging tank and the suction flow path of the compressor;
For cooling formed to be branched from a flow path connecting the heat source heat exchanger and the expansion valve to be connected to the refrigerant charging tank to discharge at least a part of the refrigerant discharged from the heat source heat exchanger to the refrigerant charging tank during cooling operation and when the refrigerant is discharged A refrigerant discharge passage,
A heating refrigerant formed to discharge at least a portion of the refrigerant discharged from the load heat exchanger to the refrigerant charging tank when a refrigerant is discharged during a heating operation by branching from a flow path connecting the load heat exchanger and the expansion valve to the refrigerant charging tank With the discharge flow path,
A refrigerant charging valve installed in the refrigerant charging passage,
A cooling refrigerant discharge valve installed in the cooling refrigerant discharge passage;
A heating refrigerant discharge valve installed in the heating refrigerant discharge passage;
A refrigerant weight sensor installed in the refrigerant charging tank and measuring the weight of the refrigerant stored in the refrigerant charging tank;
A leakage alarm device notifying the leakage of the refrigerant,
When the weight of the refrigerant measured by the refrigerant weight sensor is greater than or equal to a preset weight, the temperature of the load circulating water measured by the load temperature sensor and the temperature of the heat source circulating water measured by the heat source temperature sensor are set to a preset temperature range and Comparing and comparing the superheat degree of the suction-side refrigerant of the compressor with a preset superheat upper limit value and a preset superheat lower limit value, and controlling the opening degree of the refrigerant charging valve, the cooling refrigerant discharge valve, and the heating refrigerant discharge valve. Heat pump system capable of automatic refrigerant charging including a control unit. A weight comparison step of comparing the weight of the refrigerant stored in the refrigerant charging tank with a preset weight;
A temperature comparison step of comparing a temperature of the load circulating water flowing into the load heat exchanger and a temperature of the heat source circulating water flowing into the heat source heat exchanger with a preset set temperature range when the weight of the refrigerant is greater than the set weight;
If the temperature of the load circulating water and the temperature of the heat source circulating water are within the set temperature range, a superheat degree comparison step of comparing the superheat degree of the suction side refrigerant of the compressor with a preset first superheat upper limit value and a first superheat lower limit value Wow;
When the superheat of the refrigerant is greater than or equal to the first superheat upper limit, the refrigerant charging valve installed in the refrigerant charging passage connecting the refrigerant charging tank and the suction passage of the compressor is opened for a preset charging time, and the refrigerant charging tank is A refrigerant charging step of charging a refrigerant into the suction passage of the compressor;
When the superheat of the refrigerant is less than the first superheat lower limit, the refrigerant discharge valve installed in the refrigerant discharge passage connecting the refrigerant charging tank and the discharge passage of the condenser is opened for a preset discharge time, and from the discharge passage of the condenser. A control method of a heat pump system capable of automatically charging a refrigerant, including a refrigerant discharge step of discharging the refrigerant to the refrigerant charging tank. The method of claim 14,
When the charging time has elapsed, the refrigerant charging valve is closed, and if the superheat of the refrigerant is equal to or greater than the second superheating upper limit value set lower than the first superheating upper limit value after the preset operation time has elapsed, the refrigerant charging valve is closed. The control method of a heat pump system capable of automatic refrigerant charging, further comprising a recharging step of recharging the refrigerant by opening again during the charging time. The method of claim 14,
When the discharge time elapses, the refrigerant discharge valve is closed, and after the predetermined operation time elapses, if the superheat of the refrigerant is higher than the first superheat lower limit by a predetermined value and is less than or equal to the second superheat lower limit value And a re-discharging step of re-discharging the refrigerant by opening the refrigerant discharge valve again during the discharging time. The method of claim 14,
When the weight of the refrigerant is less than the set weight and is more than a preset minimum value, a refrigerant leakage is displayed,
When the weight of the refrigerant is less than the set weight and less than the minimum value, the method of controlling a heat pump system capable of automatic refrigerant charging to indicate a refrigerant leakage and stop the operation of the heat pump system.

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