JPWO2018025382A1 - Heat source system - Google Patents

Abstract

  The heat source system includes a heat source unit that heats and cools a fluid and a control device that controls the heat source unit. The heat source unit includes a compressor, a refrigerant flow switching device, an air-side heat exchanger, and a decompression device. The refrigerant circuit connected to the heat medium side heat exchanger via the refrigerant pipe, the fluid pipe through which the fluid exchanged with the refrigerant of the refrigerant circuit by the heat medium side heat exchanger flows, the fluid pipe, A fluid pump that supplies the heat medium side heat exchanger to the heat medium side heat exchanger, and an inlet temperature sensor that measures the temperature of the fluid flowing into the heat medium side heat exchanger. In the defrosting operation in which the heat medium side heat exchanger becomes an evaporator, the fluid pump is configured such that the flow rate of the fluid supplied to the heat medium side heat exchanger changes according to the fluid temperature measured by the inlet temperature sensor. Control system Provided with the means.

Description

  The present invention relates to a heat source system that includes a heat source unit and is used, for example, in an air conditioning chilling system.

  In general, there is known a chilling system that heats and cools an aqueous medium by exchanging heat between a refrigerant in a refrigerant circuit and an aqueous medium in a water pipe by a heat medium side heat exchanger. Among them, in an air-cooled chilling system, frost formation may occur in the air-side heat exchanger serving as an evaporator during heating. Therefore, such a chilling system requires defrosting of the air side heat exchanger. Conventionally, there has been a proposal of a defrosting operation method in an air-cooled chilling system in which a plurality of heat source units are connected to a water pipe (see, for example, Patent Document 1). Patent Document 1 discloses a defrosting operation method that avoids simultaneous defrosting of heat source units as much as possible in a heat source system including two or more heat source units and prevents a decrease in water temperature.

JP 2013-108732 A

However, in the defrosting control of Patent Literature 1, the water temperature is lowered in a single defrosting operation in which only one heat source unit is operated.

  The present invention has been made to solve the above-described problems, and provides a heat source system in which a decrease in supply water temperature is suppressed even during defrosting operation regardless of the number of heat source units. With the goal.

  A heat source system according to the present invention includes a heat source unit that heats and cools a fluid, and a control device that controls the heat source unit. The heat source unit includes a compressor, a refrigerant flow switching device, and air-side heat. A refrigerant circuit in which an exchanger, a decompression device, and a heat medium side heat exchanger are connected via a refrigerant pipe, and a fluid pipe through which the fluid that exchanges heat with the refrigerant in the refrigerant circuit by the heat medium side heat exchanger flows A fluid pump that is provided in the fluid pipe and supplies the fluid to the heat medium side heat exchanger; and an inlet temperature sensor that measures the temperature of the fluid flowing into the heat medium side heat exchanger. The flow rate of the fluid supplied to the heat medium side heat exchanger during the defrosting operation in which the air side heat exchanger serves as a condenser and the heat medium side heat exchanger serves as an evaporator. The inlet temperature sensor To vary according to the fluid temperature measured by, but including the driving control means for controlling the fluid pump.

  According to the heat source system of the present invention, since the flow rate of the fluid supplied to the heat medium side heat exchanger changes according to the fluid temperature, the heat capacity changes and the outlet temperature also changes. Therefore, even in the single operation of the heat source unit, the temperature drop of the supplied hot water during the defrosting operation can be controlled.

It is a schematic block diagram at the time of heating operation of the heat-source system which concerns on Embodiment 1 of this invention. It is a schematic block diagram at the time of the defrost operation of the heat-source system which concerns on Embodiment 1 of this invention. It is a functional block diagram of the control apparatus which concerns on Embodiment 1 of this invention. 1 is a flowchart of fluid flow rate control according to Embodiment 1 of the present invention. It is a graph which shows the relationship between inlet temperature and the evaporation temperature which freezes. It is a graph which shows the relationship between a water flow rate and the evaporation temperature which freezes. 2 is a flowchart of freezing control according to Embodiment 1 of the present invention. It is a schematic block diagram of the heat-source system which concerns on Embodiment 2 of this invention. The flowchart of the fluid flow control which concerns on Embodiment 2 of this invention is shown. The flowchart of the control of the conventional apparatus is shown.

  Below, the heat source system of this invention is demonstrated with reference to drawings. The heat source system 100 is an air-cooled chilling system, and is used as a central heat source for air conditioning inside a building, for example. The heat source system 100 performs a heating operation or a cooling operation based on the operation content specified by the user. During operation of the heat source system 100, heat exchange is performed between the refrigerant flowing through the refrigerant pipe 11 of the refrigerant circuit 2 and the fluid flowing through the fluid pipe 22, and the fluid is heated or cooled. The fluid heated or cooled by the heat source system 100 is supplied to a load side device such as an air conditioner. In the embodiment, a case where the fluid is a hydrothermal medium such as an antifreeze liquid will be described as an example.

Embodiment 1 FIG.
(Configuration of heat source system 100)
FIG. 1 is a schematic configuration diagram of the heat source system according to Embodiment 1 of the present invention during heating operation. FIG. 2 is a schematic configuration diagram of the heat source system according to Embodiment 1 of the present invention during a defrosting operation. Based on FIG.1 and FIG.2, the structure of the heat source system 100 is demonstrated below.

  The heat source system 100 includes a heat source unit 1 and a control device 50. The heat source unit 1 includes a refrigerant circuit 2, a fluid pipe 22 through which a hydrothermal medium flows, a fluid pump 20, and a pump control device 21. A compressor 3, a refrigerant flow switching device 4, an air side heat exchanger 5, a pressure reducing device 7, a heat medium side heat exchanger 8, and an accumulator 9 are connected to the refrigerant circuit 2 via a refrigerant pipe 11. .

  The compressor 3 sucks in a low-temperature and low-pressure refrigerant and compresses the refrigerant into a high-temperature and high-pressure state. The compressor 3 includes, for example, an inverter compressor capable of capacity control. The refrigerant flow switching device 4 is configured by, for example, a four-way valve or the like, and switches between a refrigerant flow during a cooling operation or a defrosting operation and a refrigerant flow during a heating operation.

  The decompression device 7 is composed of, for example, an electronic expansion valve or the like, and decompresses the refrigerant to expand it. The accumulator 9 is provided on the suction side of the compressor 3 and stores condensed liquid refrigerant. The accumulator 9 prevents the liquid refrigerant from being sucked into the compressor 3 as it is.

  The air-side heat exchanger 5 exchanges heat between air and refrigerant, and functions as an evaporator during heating operation and as a condenser during cooling operation or defrosting operation. The air-side heat exchanger 5 is provided with an air-side heat exchanger blower 6 composed of, for example, a propeller fan, and the air-side heat exchanger blower 6 supplies air to the air-side heat exchanger 5. Supply.

  The heat medium side heat exchanger 8 exchanges heat between the refrigerant and the water heat medium. The heat medium side heat exchanger 8 exchanges heat between the high-temperature and high-pressure refrigerant and the water heat medium during heating operation to generate high-temperature water, and heat-exchanges between the low-temperature and low-pressure refrigerant and the water heat medium during cooling operation. To produce cold water.

  The fluid pump 20 supplies the water heat medium to the heat medium side heat exchanger 8 through the fluid pipe 22. The fluid pump 20 has a configuration in which, for example, the rotational speed is controlled, and supplies the water flow rate FR in multiple stages such as a maximum flow rate, a large flow rate, a normal flow rate, and a small flow rate, from the larger one.

  The pump control device 21 receives a control signal from the control device 50, which will be described later, and changes the frequency at which the fluid pump 20 is operated according to the control signal. A heating medium is supplied. For example, the pump control device 21 has multi-stage drive frequencies such as a maximum frequency, a large frequency, a normal frequency, and a small frequency, and rotates the pump motor at the drive frequency.

  The heat source unit 1 further includes sensor groups 12 to 17 such as a plurality of temperature sensors and pressure sensors. The low pressure sensor 12 is installed in the suction pipe of the compressor 3 and detects the compressor suction pressure. The suction gas temperature sensor 13 is provided on the suction side of the compressor 3 and detects the suction gas temperature of the refrigerant sucked into the compressor. The outside air temperature sensor 15 detects the outside air temperature. Further, the evaporation temperature sensor 14 is provided at an intermediate position of the refrigerant pipe flowing through the heat medium side heat exchanger 8, and measures the refrigerant temperature (evaporation temperature Te) at the arrangement place.

  The high-temperature water sent from the heat source system 100 during the heating operation is sent to the load-side device, for example, is used for heating in the load-side device to become low-temperature water, and is supplied again to the heat medium-side heat exchanger 8 of the heat source system 100. Heated. The water heat medium circulates between the load side device and the heat source system 100 through the fluid pipe 22 in this way.

  The inlet temperature sensor 16 is provided in the fluid piping 22 on the inlet side of the heat medium side heat exchanger 8 and measures the water temperature (inlet temperature Twi) at the installation position. The outlet temperature sensor 17 is provided in the fluid pipe 22 on the outlet side of the heat medium side heat exchanger 8 and measures the water temperature (exit temperature Two) at the installation position.

  The control device 50 is configured by a microcomputer or the like, for example, and controls the heat source system 100. Specifically, the control device 50 detects the refrigerant pressure from a group of sensors such as the low pressure sensor 12, the intake gas temperature sensor 13, the evaporation temperature sensor 14, the outside air temperature sensor 15, the inlet temperature sensor 16, and the outlet temperature sensor 17. Information, temperature information, temperature information of the hydrothermal medium, etc. are received. The control device 50 performs operation control based on information acquired from the sensor groups 12 to 17, operation information of the heat source unit 1, and command content input by the user. Specifically, the control device 50 performs the operation and stop of the compressor 3 or the rotation speed control, the opening degree adjustment of the decompression device 7, the rotation control of the air-side heat exchanger blower 6, and the accumulator 9. . In addition, the control device 50 changes the water flow rate FR of the water heat medium supplied to the heat medium side heat exchanger 8 by the fluid pump 20 during the defrosting operation.

(Operation of heat source unit 1 during defrosting)
In the heating operation for heating the water heating medium, when frost formation is detected in the air-side heat exchanger 5, the control device 50 switches the flow of the refrigerant in the refrigerant circuit 2 and melts the attached frost by the heat of the refrigerant. To do. The detection of frost formation in the air-side heat exchanger 5 is performed, for example, when a temperature sensor is provided in the air-side heat exchanger 5 to measure the refrigerant temperature, and when the measured temperature is equal to or lower than a preset threshold temperature. Detect frost formation. In the defrosting operation of the air side heat exchanger 5, as shown in FIG. 2, the air side heat exchanger 5 becomes a condenser, and the heat medium side heat exchanger 8 becomes an evaporator. Accordingly, since the low-temperature refrigerant flows into the heat medium side heat exchanger 8, the water heat medium is cooled in the heat medium side heat exchanger 8.

(Function of control device 50)
FIG. 3 is a functional block diagram of the control apparatus according to Embodiment 1 of the present invention. The control device 50 will be described based on FIG. The control device 50 includes an operation control unit 51, a temperature determination unit 52, a freezing determination unit 53, and a storage unit 54.

  The operation control means 51 performs operation control of the refrigerant circuit 2 and flow rate control of the fluid pump 20 based on temperature information and pressure information from the sensor groups 12 to 17. Specifically, the operation control means 51 adjusts the operation frequency of the compressor 3 so that, for example, the outlet temperature Two measured by the outlet temperature sensor 17 approaches the set target temperature. Further, the operation control means 51 determines the water flow rate FR of the water heat medium supplied to the heat medium side heat exchanger 8 by the fluid pump 20 via the pump control device 21 during the defrosting operation of the air side heat exchanger 5. Change. Specifically, the operation control means 51 transmits a control signal for adjusting the drive frequency of the fluid pump 20 to the pump control device 21. The pump control device 21 changes the drive frequency according to the control signal, and changes the rotation speed of the fluid pump 20. In addition, the operation control unit 51 transmits the operation information being executed to the temperature determination unit 52 and the freezing determination unit 53. Further, the operation control means 51 changes the supplied water flow rate FR based on the determination result of the temperature determination means 52, and continues or ends the defrosting operation based on the result of the freezing determination means 53.

  The temperature determination unit 52 acquires temperature information from the inlet temperature sensor 16 and determines whether the water temperature is high or low. Specifically, during the defrosting operation, it is determined whether or not the inlet temperature Twi measured by the inlet temperature sensor 16 is lower than the first set temperature T1, and the determination result is transmitted to the operation control means 51. Further, during the defrosting operation, it is determined whether or not the measured inlet temperature Twi is lower than the second set temperature T2, and the determination result is transmitted to the operation control means 51 or the freezing determination means 53 according to the determination result. When the temperature determination is requested, the temperature determination unit 52 refers to the first set temperature T1 and the second set temperature T2 stored in the storage unit 54.

  The freezing determination means 53 acquires the inlet temperature Twi from the inlet temperature sensor 16 and acquires the evaporation temperature Te from the evaporation temperature sensor 14. In addition, the freezing determination unit 53 determines from the operation control unit 51 whether the heat source system 100 is performing a heating operation, a cooling operation, or a defrosting operation mode, and at which water flow the fluid pump 20 is operated. To obtain driving information such as The freezing determination means 53 freezes the heat medium side heat exchanger 8 when the temperature determination means 52 determines that the measured inlet temperature Twi is lower than the second set temperature T2 during the defrosting operation. Freeze determination control is performed to determine whether or not. In the freezing determination control, the freezing determination means 53 is based on the flow rate FR of water supplied to the heat medium side heat exchanger 8, the measured inlet temperature Twi, and the measured evaporation temperature Te. It is determined whether the exchanger 8 is frozen. Specifically, the freeze evaporation temperature Tf corresponding to the supplied water flow rate FR and the measured inlet temperature Twi is calculated with reference to the freezing threshold information T3 stored in the storage unit 54. The freezing determination means 53 compares the measured evaporation temperature Te with the calculated freezing evaporation temperature Tf. The freezing determination means 53 determines that the heat medium side heat exchanger 8 is frozen when the measured evaporation temperature Te is lower than the freezing evaporation temperature Tf, while the measured evaporation temperature Te is the freezing evaporation temperature. When it is higher than Tf, it is determined that the heat medium side heat exchanger 8 is not frozen. Further, the freezing determination means 53 transmits the freezing determination result to the operation control means 51. In other words, the freezing determination means 53 can change the end timing of the defrosting operation performed by the operation control means 51.

  The storage means 54 is configured by a memory such as a ROM, for example, and stores a first set temperature T1, a second set temperature T2, and a freezing threshold information T3 in advance. The first set temperature T1 is an inlet temperature at a boundary at which a decrease in the water temperature of the hydrothermal medium delivered from the heat source system 100 becomes noticeable, for example, when the heat source unit 1 performs a defrosting operation. The first set temperature T1 may be configured to be automatically set based on the cooling capacity of the refrigerant circuit, the target outlet temperature, the normal water flow rate, and the like. The second set temperature T2 is a temperature lower than the first set temperature, for example, and higher than the normal freezing temperature of the heat medium side heat exchanger 8. The freezing threshold information T3 is correspondence information between the inlet temperature Twi and the freezing evaporation temperature, and correspondence information between the water flow rate FR and the freezing evaporation temperature. The freezing determination means 53 calculates the freezing evaporation temperature Tf. It is what is referred to when doing. The freezing threshold information T3 can be stored in any format as long as it is associated and stored as a value that changes the freezing evaporation temperature corresponding to the inlet temperature Twi or the water flow rate FR, such as an equation or a table. It may be stored.

(Pump control during defrosting)
FIG. 4 shows a flowchart of fluid flow control according to the first embodiment of the present invention. During the defrosting operation, the refrigerant flows in the same direction as the cooling operation, so the outlet temperature Two decreases with respect to the inlet temperature Twi. Therefore, during the defrosting operation, there is a concern about a decrease in the supply water temperature of the heat source system 100, freezing of the heat medium side heat exchanger 8, and the like. On the other hand, in the fluid flow rate control of FIG. 4, the water flow rate FR is changed by changing the drive frequency of the fluid pump 20. The cooling capacity of the refrigerant circuit 2 is defined by the product of the water flow rate FR and the difference between the inlet temperature Twi and the outlet temperature Two. Therefore, when the cooling capacity and the inlet temperature Twi are constant, a decrease in the outlet temperature Two is suppressed when the water flow rate FR is higher than when the water flow rate FR is low.

  In the heat source system 100, for example, when the heating operation of the heat source unit 1 is started, the control device 50 starts the fluid flow rate control of FIG. First, the operation control means 51 determines whether or not the heat source unit 1 is in the defrosting operation (step ST101). When the defrosting operation is not being performed (step ST101; NO), the operation control unit 51 controls the water flow rate FR supplied by the fluid pump 20 to be a normal water flow rate (step ST104). Specifically, the operation control means 51 transmits a control signal to the pump control device 21, and the pump control device 21 rotates the fluid pump 20 at a normal frequency (for example, 40 Hz) according to the control signal. On the other hand, the operation control means 51 notifies the temperature determination means 52 when the defrosting operation is being performed (step ST101; YES). When the temperature determination unit 52 receives the notification from the operation control unit 51, the temperature determination unit 52 acquires information on the inlet temperature Twi from the inlet temperature sensor 16 of the heat source unit 1, and acquires the first set temperature T <b> 1 from the storage unit 54. Then, the temperature determination unit 52 determines whether or not the acquired inlet temperature Twi is equal to or lower than the first set temperature T1 (step ST102). The first set threshold is a preset water temperature, and is set to 30 ° C., for example. The temperature determination unit 52 notifies the operation control unit 51 of the determination result. The operation control means 51 receives the notification from the temperature determination means 52, and when the inlet temperature Twi is equal to or lower than the first set temperature T1 (step ST102; YES), increases the supplied water flow rate FR (step ST103). ). Specifically, the rotational speed of the fluid pump 20 is increased to “maximum” (for example, 60 Hz) via the pump control device 21 to suppress a decrease in the outlet temperature Two relative to the inlet temperature Twi. On the other hand, when the inlet temperature Twi is higher than the first set temperature T1, the operation control means 51 sets the supplied water flow rate FR as the normal water flow rate (step ST104). After performing Step ST103 or Step ST104, the operation control means 51 returns to Step ST101 and repeats the fluid flow rate control of Step ST101 to Step ST104. When the heating operation ends, the operation control means 51 ends the fluid flow control.

(Freeze evaporation temperature Tf)
By the way, the increase in the amount of water is effective in suppressing freezing of the heat medium side heat exchanger 8 in addition to suppressing the decrease in the outlet temperature Two. FIG. 5 is a graph showing the relationship between inlet temperature and freezing evaporation temperature. When the inlet temperature Twi is high, the freezing evaporation temperature decreases, while when the inlet temperature Twi is low, the freezing evaporation temperature increases. For example, in the case where the water flow rate FR and the evaporation temperature Te as the cooling capacity of the refrigerant circuit 2 are constant, if the inlet temperature Twi of the hydrothermal medium is low, the outlet temperature Two is correspondingly low, so that it is easy to freeze. Become.

  FIG. 6 is a graph showing the relationship between water flow rate and freezing evaporation temperature. When the water flow rate FR supplied to the heat medium side heat exchanger 8 is large, the freezing evaporation temperature is lowered. On the other hand, when the water flow rate FR is small, the freezing evaporation temperature is raised. For example, when the water flow rate FR is large, even if the inlet temperature Twi and the evaporation temperature Te are constant, the heat capacity of the water heat medium flowing through the heat medium side heat exchanger 8 is increased, so that a decrease in the outlet temperature Two is suppressed, The heat medium side heat exchanger 8 is not easily frozen.

  Further, by utilizing the relationship between the inlet temperature Twi and the freezing evaporation temperature and the relationship between the water flow rate FR and the freezing evaporation temperature, freezing of the heat medium side heat exchanger 8 is suppressed based on the evaporation temperature Te. You can also In the heat source system 100 in which the water flow rate FR changes, the heat capacity changes according to the change in the water flow rate FR. Therefore, in order to detect the freezing of the heat medium side heat exchanger 8 during the defrosting operation of the air side heat exchanger 5, a decrease in the inlet temperature Twi or the outlet temperature Two is detected and the defrosting operation is terminated as in the conventional case. When controlling, it is necessary to set the threshold of freezing detection to a high temperature for safety.

  FIG. 7 shows a flowchart of the freezing control according to the first embodiment of the present invention. When the inlet temperature Twi falls below a predetermined temperature, the control device 50 detects freezing by comparing the evaporation temperature Te with the freezing evaporation temperature Tf with respect to the inlet temperature Twi and the water flow rate FR.

  In the heat source system 100, for example, when the heating operation of the heat source unit 1 is started, the control device 50 starts the refrigeration control of FIG. First, the operation control means 51 determines whether or not the heat source unit 1 is in the defrosting operation (step ST111). The operation control means 51 notifies the temperature determination means 52 when the defrosting operation is being performed (step ST111; YES). On the other hand, when the defrosting operation is not being performed (step ST111; NO), the operation control unit 51 returns to step 111 and monitors whether the defrosting operation has been started during the heating operation. Next, when receiving the notification from the operation control unit 51, the temperature determination unit 52 acquires the temperature information of the inlet temperature Twi from the inlet temperature sensor 16 of the heat source unit 1, and acquires the second set temperature T2 from the storage unit 54. To do. And the temperature determination means 52 determines whether the acquired inlet temperature Twi is below 2nd setting temperature (step ST112). The second set temperature T2 is a preset water temperature, and is, for example, 15 ° C. here. When the operation control means 51 determines that the inlet temperature Twi is equal to or lower than the second set temperature T2 (step ST112; YES), the temperature determination means 52 notifies the freezing determination means 53. On the other hand, when the inlet temperature Twi is higher than the second set temperature (step ST112; NO), the temperature determination unit 52 notifies the operation control unit 51. When the operation control unit 51 receives the notification from the temperature determination unit 52, the operation control unit 51 continues the defrosting operation (step ST115). On the other hand, when the operation determination unit 53 receives the notification from the temperature determination unit 52, the operation control unit 51 receives the evaporating temperature sensor 14 and the inlet. Temperature information is acquired from the temperature sensor 16. Further, the freezing determination unit 53 acquires operation information regarding the water flow rate set in the fluid pump 20 from the operation control unit 51. Then, the freezing determination unit 53 refers to the freezing threshold information T3 in the storage unit 54, and calculates the freezing evaporation temperature Tf according to the evaporation temperature Te, the inlet temperature Twi, and the water flow rate FR. Further, the freezing determination means 53 determines whether or not the acquired evaporation temperature Te is equal to or lower than the calculated frozen evaporation temperature Tf (step ST113). The result of the freeze determination is notified from the freeze determination means 53 to the operation control means 51. When the evaporation temperature Te is equal to or lower than the freezing evaporation temperature Tf (step ST113; YES), the operation control means 51 ends the defrosting operation (step ST114). That is, when the water heat medium having the set water flow rate FR and the inlet temperature Twi passes through the heat medium side heat exchanger 8 having the evaporation temperature Te, the water temperature is lowered to the extent that freezing occurs at the outlet temperature. In this case, the defrosting operation is terminated and the occurrence of freezing is suppressed. On the other hand, when the evaporation temperature Te is higher than the freezing evaporation temperature Tf (step ST113; NO), the operation control means 51 determines that the heat medium side heat exchanger 8 is not frozen and continues the defrosting operation (step). ST115). The operation control means ends or continues the defrosting operation in step ST114 or step ST115, and then returns to step ST111 to repeat the freezing control. The operation control means ends the freezing control when the heating operation ends.

  The freezing control is effective in the heat source system 100 in which the water flow rate FR supplied from the fluid pump 20 to the heat medium side heat exchanger 8 is changed because the freezing determination can be made taking into account the change in the water flow rate FR. The control device 50 can be implemented by using both the freezing control shown in FIG. 7 and the flow rate control shown in FIG.

  As described above, in the first embodiment, the heat source system 100 includes the heat source unit 1 that heats and cools the fluid and the control device 50 that controls the heat source unit 1. In the heat source system 100, the heat source unit 1 includes the compressor 3. The refrigerant circuit 2 in which the refrigerant flow switching device 4, the air-side heat exchanger 5, the decompression device 7, and the heat medium-side heat exchanger 8 are connected via the refrigerant pipe 11, and the heat medium-side heat exchanger 8. A fluid pipe 22 through which a fluid that exchanges heat with the refrigerant in the refrigerant circuit 2 flows, a fluid pump 20 that is provided in the fluid pipe 22 and supplies the fluid to the heat medium side heat exchanger 8, and the heat medium side heat exchanger 8 An inlet temperature sensor 16 for measuring the temperature of the fluid flowing in, and the control device 50 performs a defrosting operation in which the air-side heat exchanger 5 is a condenser and the heat medium-side heat exchanger 8 is an evaporator. Supplied to the heat exchanger 8 on the heat medium side As the fluid flow rate changes according to the fluid temperature Twi measured by the inlet temperature sensor 16 that is one having the operation control means 51 for controlling the fluid pump 20.

  As a result, even if the heat source unit 1 constituting the heat source system 100 is constituted by a single unit or a plurality of units, a temperature decrease during defrosting of the hydrothermal medium supplied from the heat source system 100 is suppressed. The

  The control device 50 further includes a temperature determination unit 52 that determines whether or not the measured fluid temperature Twi is lower than the first set temperature T1 during the defrosting operation, and the operation control unit 51 is configured to perform the defrosting operation. When it is determined that the measured fluid temperature Twi is lower than the first set temperature T1, the supplied fluid flow rate FR is increased from the normal flow rate.

  As a result, when the fluid temperature Two at the inlet of the heat medium side heat exchanger 8 is low during the defrosting operation, the water flow rate FR of the supplied water heat medium is increased, and therefore the water heat medium supplied by the heat source system 100 is increased. Temperature drop is suppressed. Moreover, freezing of the heat medium side heat exchanger 8 is suppressed.

  Further, the heat source unit 1 further includes an evaporation temperature sensor 14 that measures the evaporation temperature of the refrigerant, and the control device 50 further includes the supplied fluid flow rate FR, the measured fluid temperature Twi, and the evaporation during the defrosting operation. Based on the evaporation temperature Te measured by the temperature sensor 14, it is provided with a freezing determination means 53 that determines whether or not the heat medium side heat exchanger 8 is frozen, and the operation control means 51 includes a heat medium side heat exchanger. When it is determined that 8 does not freeze, the defrosting operation is continued.

  Thus, freezing control is performed in consideration of the difference in freezing and evaporation temperature Tf due to the difference in water flow rate FR. Even when the water temperature is low, the defrosting operation of the air side heat exchanger 5 can be continued without freezing the heat medium side heat exchanger 8 depending on the water flow rate FR. In addition, if the freezing control is configured to increase the flow rate in order to suppress freezing, the defrosting operation is continued even at a lower temperature. Therefore, although the defrosting is incomplete, it is possible to avoid the defrosting operation being stopped in order to prevent the heat medium side heat exchanger 8 from freezing.

  Further, the control device 50 further includes a temperature determination unit 52 that determines whether or not the measured fluid temperature Twi is lower than the second set temperature T2 during the defrosting operation, and the freezing determination unit 53 is configured during the defrosting operation. When it is determined that the measured fluid temperature Twi is lower than the second set temperature T2, it is determined whether or not the heat medium side heat exchanger 8 is frozen. Thus, the control device 50 can set a threshold value for the temperature of the fluid and can be used as a condition for the freezing determination unit 53 to start the freezing determination.

  The freezing determination means 53 calculates a freezing and evaporation temperature Tf according to the supplied fluid flow rate FR and the measured fluid temperature Twi, and when the measured evaporation temperature Te is lower than the calculated frozen and evaporation temperature Tf. Is determined to freeze, and if the measured evaporation temperature Te is higher than the calculated freeze evaporation temperature Tf, it is determined not to freeze.

  Thus, since the threshold value (freeze evaporation temperature Tf) is calculated according to the inlet temperature Twi and the water flow rate FR, a highly accurate freezing determination is made. Therefore, for example, when the inlet temperature Twi is high or the water flow rate FR is large, the heat source system 100 can perform the defrosting operation longer than when the defrosting operation is performed based on the conventional freezing determination.

  Further, the operation control means 51 adjusts the drive frequency of the corresponding fluid pump 20 to change the supplied fluid flow rate FR. When the supplied fluid flow rate FR is increased, the operation frequency of the fluid pump 20 is increased. Is increased and the fluid flow rate FR to be supplied is decreased, the drive frequency of the fluid pump 20 is decreased. Thus, if the drive frequency of the fluid pump 20 and the water flow rate FR are synchronized, the control device 50 can change the water flow rate FR in multiple stages by transmitting a control signal corresponding to the target water flow rate. Can do.

Embodiment 2. FIG.
In the second embodiment, the heat source system 100 includes a plurality of heat source units 1a to 1c having the same configuration as the heat source unit 1 of the first embodiment. The plurality of heat source units 1a to 1c are connected in parallel so that the fluid pipes 22a to 22c merge with each other on the upstream side and the downstream side of the heat medium side heat exchangers 8a to 8c. After the water heating medium supplied from the hot water storage tank to the heat source system 100 branches and flows to the heat source units 1a to 1c at the upstream junction, and is heated or cooled by the heat medium side heat exchangers 8a to 8c. It merges again at the downstream junction, and is sent out from the heat source system 100 and returned to the hot water storage tank. Hereinafter, in the heat source system 100 during the heating operation, the heat source unit 1a of the plurality of heat source units 1a to 1c is in the defrosting operation, and the remaining heat source units 1b and 1c are not performing the defrosting operation. To do.

  FIG. 9 shows a flow chart of fluid flow rate control according to the second embodiment of the present invention. Although the refrigerant circuit is not illustrated in FIG. 9, each of the heat source units 1a to 1c includes the same refrigerant circuit as that in the first embodiment. In the second embodiment, the control device 50 controls the plurality of heat source units 1a to 1c as a whole, distinguishes them from each other, manages them, and can control them individually.

(Pump control during defrosting)
In Embodiment 2, when the inlet temperature Twi is higher than a predetermined temperature in the heat source unit 1a during the defrosting operation, the control device 50 supplies the fluid pump 20a of the heat source unit 1a to the heat medium side heat exchanger 8a. Reduce the water flow rate FRa. As a result, the amount of water supplied by the cooled heat medium is suppressed, and a decrease in the water temperature sent to the hot water storage tank is suppressed. In the heat source system 100 configured by the plurality of heat source units 1a to 1c, the heat source units 1b and 1c that are not being defrosted can supply hot water, which is lower than in the case of the heat source system configured by a single heat source unit. The water flow rate FRa of the heat source unit 1a during defrosting can be reduced to the temperature.

  When the heating operation is started in the heat source system 100, the control device 50 starts the fluid flow control of FIG. First, the operation control means 51 determines whether there is a heat source unit in the defrosting operation among the plurality of heat source units 1a to 1c (step ST201). When there is no heat source unit in the defrosting operation (step ST201; NO), the operation control means 51 sets the water flow rates FRa to FRc supplied by the fluid pumps 20a to 20c to the normal water flow rate (step ST207). Specifically, the operation control means 51 transmits a control signal to the pump control devices 21a to 21c to rotate the fluid pumps 20a to 20c at a normal frequency (for example, 40 Hz). On the other hand, the operation control means 51 notifies the temperature determination means 52 when there is the heat source unit 1a in the defrosting operation (step ST201; YES). Upon receiving the notification from the operation control means 51, the temperature determination means 52 acquires the information on the inlet temperature Twi from the inlet temperature sensor 16a of the heat source unit 1a during defrosting, and also obtains the first set temperature T1 from the storage means 54. get. Then, the temperature determination unit 52 determines whether or not the acquired inlet temperature Twi is equal to or lower than the first set temperature T1 (step ST202). The first set temperature T1 is a water temperature set in advance, and is set to 30 ° C., for example. The temperature determination unit 52 notifies the operation control unit 51 of the determination result. The operation control means 51 receives the notification from the temperature determination means 52, and when the inlet temperature Twi is equal to or lower than the first set temperature T1 (step ST202; YES), the operation control means 51 sets the water flow rate FRa of the heat source unit 1a during defrosting. The maximum water flow rate is set (step ST203). Specifically, the drive frequency of the fluid pump 20a is maximized (for example, 60 Hz). Further, the operation control means 51 sets the water flow rates FRb and FRc of the heat source units 1b and 1c not being defrosted to the normal water flow rate (step ST204). On the other hand, when the acquired inlet temperature Twi is higher than the first set temperature T1 (step ST202; NO), the operation control means 51 sets the water flow rate FRa of the heat source unit 1a during defrosting to a small water flow rate (step ST205). . Specifically, the operation control means 51 makes the drive frequency of the fluid pump 20a small (for example, 30 Hz). Moreover, the operation control means 51 makes the water flow rates FRb and FRc of the heat source units 1b and 1c that are not defrosted to a large flow rate (step ST206). Specifically, the operation control means 51 increases the drive frequency of the fluid pumps 20b and 20c (for example, 50 Hz). In step ST204, step ST206, or step ST207, the operation control means 51 sets the flow rate of each fluid pump, and then returns to step ST201 to repeat the fluid flow rate control. When the heating operation ends, the operation control means 51 ends the fluid flow control.

  Therefore, when the inlet temperature Twi is higher than the first set temperature T1, the amount of water supplied by the heat source unit 1a during defrosting increases the water flow rates FRb and FRc of the heat source units 1b and 1c that are not defrosting. The decrease in the flow rate of water supplied from the heat source system 100 is suppressed.

  The control apparatus 50 performs frequency control of the corresponding compressor 3 so that the outlet temperature Two corresponding to the plurality of heat source units 1a to 1c becomes the target water temperature. In step ST206, in the heat source units 1b and 1c that are not in the defrosting operation, since the amount of water is larger than usual, there is a concern that the increase in the outlet temperature Two is suppressed and becomes lower than the target water temperature. However, in the configuration in which the frequency control of the compressor 3 is performed, the compressor frequency of the heat source units 1b and 1c that are not being defrosted is increased and the heating capacity is increased, so that the heat source unit 1a that is being defrosted is reduced. The drop in water temperature is backed up.

  In step ST204, the operation control unit 51 sets the water flow rates FRb and FRc of the heat source units 1b and 1c not being defrosted to the normal water flow rate, but is not limited thereto. For example, if the water flow rates FRb and FRc are increased, the heat source unit 1a can be backed up. In step ST203, since the heat source unit 1a also has the maximum water flow rate, there is a concern that the total water amount increases when the heat source units 1b and 1c are operated at a large water flow rate. Therefore, the operation control means 51 may be configured to set the water flow rates FRb and FRc of the heat source units 1b and 1c to a low water flow rate in step ST204.

  In the second embodiment, the heat source system 100 includes a plurality of heat source units 1a to 1c, and the plurality of heat source units 1a to 1c have fluid pipes 22a to 22c connected in parallel to each other, and the operation control means 51 includes a plurality of heat sources. Among the units 1a to 1c, the first heat source unit 1a is in the defrosting operation and the second heat source units 1b and 1c are not in the defrosting operation, and the measured fluid temperature Twi of the first heat source unit 1a is the first. When it is determined that the temperature is higher than one set temperature T1, the fluid flow rate FRa supplied to the first heat source unit 1a is made smaller than the normal flow rate, and the fluid flow rates FRb and FRc supplied to the second heat source units 1b and 1c are set to normal More than the flow rate.

  Accordingly, since the heat source system 100 includes a plurality of heat source units 1a to 1c, when the fluid temperature Twi is higher than the first set temperature T1, the flow rate cooled by the heat source unit 1a during defrosting is reduced and the others The heat supply units 1b and 1c can back up the amount of supplied water and the supply temperature as a whole.

  Each of the heat source units 1a to 1c further includes outlet temperature sensors 17a to 17c that measure the outlet temperature of the fluid flowing out from the heat medium side heat exchangers 8a to 8c, and the operation control unit 51 includes the second heat source unit 1b. , 1c, the frequency of the compressor 3 of the second heat source units 1b, 1c is adjusted so that the outlet temperature Two measured at 1c approaches the set target temperature.

  Thus, even when the water flow rates FRb and FRc of the other heat source units 1b and 1c are large, the heating capacity is increased. Therefore, even when there is the heat source unit 1a during defrosting, the water temperature supplied from the heat source system 100 Reduction is suppressed.

  In addition, embodiment of this invention is not limited to the said embodiment, A various change can be performed. For example, in the heat source system 100 including the plurality of heat source units 1a to 1c, the case where one control device 50 controls the plurality of heat source units 1a to 1c has been described. For example, each heat source unit 1a to 1c is used. You may comprise 1c provided with the control apparatuses 50a-50c. In this case, for example, one control device 50a obtains operation information and the like from the other heat source units 1b and 1c, performs the fluid flow control of FIG. 9, and changes the water flow rate to the other control devices 50b and 50c. Just notify.

  The fluid pump 20 only needs to be able to change the water flow rate FR of the hydrothermal medium to be sent out in a plurality of stages, and may be constituted by a pump that obtains kinetic energy for circulating the fluid by reciprocating motion instead of rotating motion.

  Further, in the heat source system 100 of the second embodiment, the end timing of the defrosting operation may be controlled by freezing determination for each of the plurality of heat source units 1a to 1c as in the first embodiment.

  Moreover, although the case where the load side apparatus was an air conditioner was demonstrated, a floor heating system or a hot water supply system etc. may be sufficient, for example. In addition, a storage tank is provided between the heat source system and the load side equipment, and the water heat medium is circulated between the heat source system and the storage tank and between the storage tank and the load side equipment. May be.

  1, 1a to 1c Heat source unit, 2 Refrigerant circuit, 3 Compressor, 4 Refrigerant flow switching device, 5 Air side heat exchanger, 6 Air side heat exchanger blower, 7 Pressure reducing device, 8, 8a to 8c Heat medium side Heat exchanger, 9 Accumulator, 11 Refrigerant piping, 12 Low pressure sensor, 13 Intake gas temperature sensor, 14 Evaporation temperature sensor, 15 Outside air temperature sensor, 16, 16a-16c Inlet temperature sensor, 17, 17a-17c Outlet temperature sensor, 20, 20a-20c Fluid pump, 21, 21a-21c Pump control device, 22, 22a-22c Fluid piping, 50 Control device, 51 Operation control means, 52 Temperature determination means, 53 Freezing determination means, 54 Storage means, 100 Heat source System, T1 first set temperature, T2 second set temperature, T3 freezing threshold information, FR, FRa to FRc water flow rate ( Fluid flow), Twi fluid temperature (inlet temperature), Two outlet temperature, Te evaporation temperature, Tf freeze evaporation temperature.

Claims (8)

In a heat source system comprising a heat source unit that heats and cools a fluid, and a control device that controls the heat source unit,
The heat source unit is
A refrigerant circuit in which a compressor, a refrigerant flow switching device, an air side heat exchanger, a decompression device, and a heat medium side heat exchanger are connected via a refrigerant pipe;
A fluid pipe through which the fluid exchanged with the refrigerant in the refrigerant circuit flows by the heat medium side heat exchanger;
A fluid pump provided in the fluid piping and supplying the fluid to the heat medium side heat exchanger;
An inlet temperature sensor for measuring the temperature of the fluid flowing into the heat medium side heat exchanger,
The control device includes:
During the defrosting operation in which the air side heat exchanger becomes a condenser and the heat medium side heat exchanger becomes an evaporator, the flow rate of the fluid supplied to the heat medium side heat exchanger is measured by the inlet temperature sensor. A heat source system comprising operation control means for controlling the fluid pump so as to change in accordance with the measured fluid temperature. The control device further includes:
A temperature determining means for determining whether or not the measured fluid temperature is lower than a first set temperature during the defrosting operation;
The said operation control means makes the said supplied fluid flow volume more than a normal flow volume, when it determines with the said measured fluid temperature being lower than the said 1st preset temperature at the time of the said defrost operation. Heat source system. A plurality of the heat source units are provided, and the plurality of heat source units have the fluid pipes connected in parallel to each other,
The operation control means includes
The first heat source unit among the plurality of heat source units is in the defrosting operation and the second heat source unit is not in the defrosting operation, and the measured fluid temperature of the first heat source unit is the first setting. When it is determined that the temperature is higher than the temperature, the supplied fluid flow rate of the first heat source unit is made smaller than the normal flow rate, and the supplied fluid flow rate of the second heat source unit is made larger than the normal flow rate. The heat source system according to claim 2. Each of the heat source units further includes
An outlet temperature sensor for measuring an outlet temperature of the fluid flowing out of the heat medium side heat exchanger;
The heat source system according to claim 3, wherein the operation control means adjusts the frequency of the compressor of the second heat source unit so that the measured outlet temperature approaches the set target temperature in the second heat source unit. Each of the heat source units further includes
An evaporation temperature sensor for measuring the evaporation temperature of the refrigerant;
The control device further includes:
Freezing determination means for determining whether or not the heat medium side heat exchanger is frozen based on the supplied fluid flow rate, the measured fluid temperature, and the measured evaporation temperature during the defrosting operation. With
The heat source system according to any one of claims 1 to 4, wherein the operation control unit continues the defrosting operation when it is determined that the heat medium side heat exchanger does not freeze. The control device further includes:
A temperature determining means for determining whether or not the measured fluid temperature is lower than a second set temperature during the defrosting operation;
The freezing determination means determines whether or not the heat medium side heat exchanger is frozen when it is determined that the measured fluid temperature is lower than the second set temperature during the defrosting operation. Item 6. The heat source system according to Item 5.   The freezing determination means calculates a freeze evaporation temperature according to the supplied fluid flow rate and the measured fluid temperature, and freezes when the measured evaporation temperature is lower than the calculated freeze evaporation temperature. The heat source system according to claim 5 or 6, wherein the heat source system is determined and determined not to freeze when the measured evaporation temperature is higher than the calculated freeze evaporation temperature.   The operation control means adjusts the driving frequency of the corresponding fluid pump to change the supplied fluid flow rate, and increases the driving frequency of the fluid pump when increasing the supplied fluid flow rate. The heat source system according to any one of claims 1 to 7, wherein when the flow rate of the supplied fluid is decreased, the driving frequency of the fluid pump is decreased.

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