WO2018189859A1

WO2018189859A1 - Refrigeration cycle device and defrost operation method for refrigeration cycle device

Info

Publication number: WO2018189859A1
Application number: PCT/JP2017/015123
Authority: WO
Inventors: 康平名島
Original assignee: 三菱電機株式会社
Priority date: 2017-04-13
Filing date: 2017-04-13
Publication date: 2018-10-18
Also published as: GB2574541A; JP6723442B2; GB2574541B; GB201913233D0; JPWO2018189859A1

Abstract

The refrigeration cycle device comprises: a compressor; a first heat exchanger; a plurality of throttling devices; a plurality of second heat exchangers; a first temperature detector that detects the ambient temperature around the first heat exchanger; a storage unit that stores the heating capacity of each of the plurality of second heat exchangers; and a control device that executes a heating operation that causes the first heat exchanger to function as an evaporator and at least part of the plurality of second heat exchangers to function as condensers. During a heating operation, the control device selects either a first defrosting operation or a second defrosting operation on the basis of the value detected by the first temperature detector and the total heating capacity of the second heat exchangers functioning as condensers, and if the first defrosting operation has been selected, starts the first defrosting operation when the operation time of the heating operation reaches a first operation time, whereas if the second defrosting operation has been selected, starts the second defrosting operation when the operation time of the heating operation reaches a second operation time, which is shorter than the first operation time.

Description

Refrigeration cycle apparatus and defrosting operation method for refrigeration cycle apparatus

The present invention relates to a refrigeration cycle apparatus that performs a defrosting operation for removing frost adhering to a heat exchanger, and a defrosting operation method for the refrigeration cycle apparatus.

There is an air conditioner equipped with a refrigeration cycle having a heat source side heat exchanger and a use side heat exchanger. During the heating operation of such an air conditioner, the refrigerant circulating in the refrigeration cycle dissipates heat to the air supplied to the heat exchanger on the use side that functions as a condenser, and the heated air is sent to the air-conditioning target space. The heat source side heat exchanger that functions as an evaporator during heating operation may be installed outdoors. For example, if the heating operation is executed when the outside air temperature is low, such as in winter, frost may adhere to the heat exchanger on the heat source side that functions as an evaporator. When frost grows, it may cause a decrease in refrigeration cycle capacity or a failure of the heat exchanger on the heat source side. For this reason, it is necessary to perform the defrosting operation which melt | dissolves the frost adhering to the heat exchanger by the side of a heat source for every predetermined time.

Here, as an air conditioner that performs a defrosting operation, when a temperature condition in which frost appears to be attached to an outdoor heat exchanger that is a defrosting target is set in advance, and a heating operation is performed A technique for starting a defrosting operation when the temperature of the outdoor heat exchanger becomes equal to or lower than a predetermined temperature has been proposed (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2015-218940 (page 11)

The conventional technology detects the frosting state of the heat exchanger based on the rule of thumb from the temperature of the heat exchanger to be defrosted, and starts the defrosting operation. However, there is a possibility that the actual frosting state of the heat exchanger cannot be accurately detected only from the temperature of the heat exchanger to be defrosted. For this reason, heating operation may be performed in a state where the heating capacity is low due to a large amount of frost formation on the heat exchanger, or the time of the defrosting operation may be prolonged. Then, when considering the heating integration capability in a period composed of a set of heating operation and defrosting operation to be executed in succession, this heating integration capability has been reduced.

The present invention has been made against the background of the above-described problems, and provides a refrigeration cycle apparatus that performs a defrosting operation while suppressing a decrease in accumulated heating capacity. Moreover, the defrost operation method of the refrigerating-cycle apparatus which suppresses the fall of integrated heating capability is provided.

The refrigeration cycle apparatus of the present invention includes a compressor, a first heat exchanger, a plurality of expansion devices, a plurality of second heat exchangers, and a first temperature detection for detecting an ambient temperature of the first heat exchanger. A storage unit that stores the heating capacity of each of the plurality of second heat exchangers, the first heat exchanger functioning as an evaporator, and at least a part of the plurality of second heat exchangers A control device that performs a heating operation that functions as a condenser, and the control device is configured to detect the detected value of the first temperature detector and the condensing of the plurality of second heat exchangers during the heating operation. If either the first defrosting operation or the second defrosting operation is selected based on the total value of the heating capacity of what is functioning as a cooler, and the first defrosting operation is selected, the heating is performed. When the operation time of the operation reaches the first operation time, the first defrosting operation is started. In which the operating time of the heating operation is started the second defrosting operation to reach the second operating time shorter than the first operation time in case of selecting the second defrosting operation.

A defrosting operation method for a refrigeration cycle apparatus according to the present invention is a defrosting operation method for a refrigeration cycle apparatus including a compressor, a first heat exchanger, a plurality of expansion devices, and a plurality of second heat exchangers, During the heating operation in which the first heat exchanger functions as an evaporator and at least a part of the plurality of second heat exchangers functions as a condenser, the ambient temperature of the first heat exchanger is detected, Based on the ambient temperature of the first heat exchanger and the total heating capacity of the plurality of second heat exchangers functioning as the condenser, the first defrosting operation and the second defrosting are performed. When the operation is selected and the first defrosting operation is selected, the first defrosting operation is started when the operation time of the heating operation reaches the first operation time, and the second defrosting operation is started. When operation is selected, the operation time of the heating operation is shorter than the first operation time. Wherein upon reaching the second operating time in which the second defrosting operation is started.

According to the present invention, based on the ambient temperature of the first heat exchanger that functions as a condenser and the total value of the heating capacity of the second heat exchanger that functions as an evaporator, the operating time of the heating operation is varied. The defrosting operation is started. For this reason, compared with the case where a defrost operation is started based on an empirical rule from the temperature of the heat exchanger used as a defrost object, the actual frost formation state to the 1st heat exchanger used as a defrost object is more. The defrosting operation can be started at the reflected timing. Therefore, it is possible to suppress a decrease in the integrated heating capacity in a period including a set of heating operations and a defrosting operation that are continuously executed.

It is a figure which shows an example of the circuit structure of the refrigerating-cycle apparatus which concerns on Embodiment 1. FIG. 3 is a functional block diagram of the refrigeration cycle apparatus according to Embodiment 1. FIG. It is a flowchart explaining the heating operation and the defrosting operation of the refrigeration cycle apparatus according to Embodiment 1. It is a figure which illustrates the integrated heating capability of the 1st defrost operation which concerns on Embodiment 1. FIG. It is a figure which illustrates the integrated heating capability of the 2nd defrost operation which concerns on Embodiment 1. FIG. It is a figure which shows an example of the circuit structure of the refrigerating-cycle apparatus which concerns on Embodiment 2. FIG. 6 is a functional block diagram of a refrigeration cycle apparatus according to Embodiment 2. FIG. 6 is a flowchart illustrating a heating operation and a defrosting operation of the refrigeration cycle apparatus according to Embodiment 2.

Hereinafter, an embodiment when the refrigeration cycle apparatus of the present invention is applied to an air conditioner will be described with reference to the drawings as appropriate. In the following drawings, the size relationship of each component may be different from the actual one. In the following drawings, the same reference numerals denote the same or corresponding parts, and this is common throughout the entire specification. Furthermore, the forms of the constituent elements shown in the entire specification are merely examples, and are not limited to these descriptions.

Embodiment 1 FIG.
1 is a diagram illustrating an example of a circuit configuration of a refrigeration cycle apparatus 100 according to Embodiment 1. FIG. The refrigeration cycle apparatus 100 is used as an air conditioner that heats or cools the air-conditioning target space. In FIG. 1, the refrigerant flow in the cooling operation is indicated by broken line arrows, and the refrigerant flow in the heating operation is indicated by solid line arrows.

<Configuration of refrigeration cycle apparatus 100>
The refrigeration cycle apparatus 100 is configured by connecting a compressor 1, a first heat exchanger 2, a plurality of

expansion devices

3a and 3b, and a plurality of

second heat exchangers

4a and 4b through refrigerant pipes. It has a vapor compression refrigeration cycle. The refrigerant circulating in the refrigeration cycle is, for example, a non-azeotropic refrigerant mixture in which R410A, R404A, R32, HFO1234yf, R32 and HFO1234yf, etc. are mixed at a constant ratio. The refrigeration cycle apparatus 100 includes a first temperature detector 5 that detects the ambient temperature of the first heat exchanger 2. Furthermore, the refrigeration cycle apparatus 100 of the present embodiment includes a refrigerant flow switching device 6, an accumulator 7, a check valve 8, and an outdoor fan 9.

The members constituting the refrigeration cycle apparatus 100 are accommodated in a case of the outdoor unit 30 that is a heat source unit or a case of the

indoor units

40a and 40b that are use side units. In the present embodiment, a configuration in which two

indoor units

40a and 40b are connected in parallel to one outdoor unit 30 is illustrated, but the number of outdoor units 30 and

indoor units

40a and 40b is an example. However, the number of units shown is not limited.

(Outdoor unit 30)
The outdoor unit 30 is installed in a space different from the air-conditioning target space, for example, outdoors. The outdoor unit 30 houses the compressor 1, the check valve 8, the refrigerant flow switching device 6, the first heat exchanger 2, the accumulator 7, and the outdoor fan 9.

Compressor 1 compresses the refrigerant flowing in through accumulator 7 and discharges it as a high-temperature and high-pressure gas refrigerant. The compressor 1 can be comprised by a rotary compressor, a scroll compressor, a screw compressor, a reciprocating compressor etc., for example. Moreover, it is good to comprise the compressor 1 with the inverter compressor which can control capacity | capacitance.

The check valve 8 is a valve that is provided in the refrigerant pipe on the discharge side of the compressor 1 and allows the refrigerant to flow only in one direction. The check valve 8 prevents the refrigerant discharged from the compressor 1 from flowing back to the compressor 1. The check valve 8 is not an essential component of the refrigeration cycle apparatus 100.

The refrigerant flow switching device 6 has a valve provided in the refrigerant pipe on the discharge side of the compressor 1, and the first heat exchange is performed on the flow path of the refrigerant discharged from the compressor 1 by the open / close state of this valve. Switch to one of the heat exchanger 2 side and the

second heat exchanger

4a, 4b side. For example, the refrigerant flow switching device 6 can be configured by a combination of a two-way valve or a three-way valve, or a four-way valve.

The first heat exchanger 2 acts as an evaporator during heating operation, and acts as a condenser during cooling operation. Heat exchange is performed between the refrigerant flowing through the first heat exchanger 2 and a heat exchange fluid such as air supplied to the first heat exchanger 2. For example, the 1st heat exchanger 2 can be comprised with a fin and tube type heat exchanger, a microchannel heat exchanger, etc. Here, a case where the first heat exchanger 2 is a fin-and-tube heat exchanger will be described as an example.

The first temperature detector 5 detects the ambient temperature of the first heat exchanger 2. The ambient temperature of the first heat exchanger 2 is the air temperature in the space where the first heat exchanger 2 is installed. When the first heat exchanger 2 is installed outdoors, the first temperature detector 5 detects the outside air temperature.

The accumulator 7 is an excess refrigerant storage container provided in the refrigerant pipe on the suction side of the compressor 1. Due to the difference in the refrigerant flow rate between the heating operation and the cooling operation, the transient refrigerant flow change that occurs when the number of operating units of the plurality of

indoor units

40a and 40b changes, or the refrigerant flow change that occurs due to load conditions, Surplus refrigerant can be generated in the refrigeration cycle. The accumulator 7 stores such surplus refrigerant. In the accumulator 7, the liquid refrigerant and the gas refrigerant are separated, and the gas refrigerant is supplied to the compressor 1. The accumulator 7 is not an essential component of the refrigeration cycle apparatus 100.

The outdoor fan 9 is an example of an apparatus that supplies the first heat exchanger 2 with a heat exchange fluid that exchanges heat with the refrigerant flowing through the first heat exchanger 2. For example, the outdoor fan 9 can be configured by a propeller fan having a plurality of blades. The outdoor fan 9 only needs to be installed in a place where air can be supplied to the first heat exchanger 2.

(

Indoor units

40a, 40b)
The

indoor units

40a and 40b are each installed in the air-conditioning target space. The indoor unit 40a houses the expansion device 3a, the second heat exchanger 4a, and the indoor fan 10a, and the indoor unit 40b houses the expansion device 3b, the second heat exchanger 4b, and the indoor fan 10b. In addition, since the function and basic structure are the same as the indoor unit 40a and the member accommodated therein, and the indoor unit 40b and the member accommodated in the indoor unit 40a, the indoor unit 40a and the member accommodated therein are here. Explained as an example.

The expansion device 3a is installed in a refrigerant pipe that connects the first heat exchanger 2 and the second heat exchanger 4a, and is an apparatus that expands and depressurizes the refrigerant that passes by restricting the flow path of the refrigerant. . For example, the expansion device 3a can be configured by an electric expansion valve having a valve capable of adjusting the flow rate of the refrigerant. In addition to the electronic expansion valve, a mechanical expansion valve employing a diaphragm for the pressure receiving portion, a capillary tube, or the like can be used as the expansion device 3a.

The second heat exchanger 4a acts as a condenser during heating operation and acts as an evaporator during cooling operation. Heat exchange is performed between the refrigerant flowing through the second heat exchanger 4a and the air supplied to the second heat exchanger 4a to generate heating air or cooling air. For example, the 2nd heat exchanger 4a can be comprised with a fin and tube type heat exchanger, a microchannel heat exchanger, etc. Here, the second heat exchanger 4a configured by a fin-and-tube heat exchanger having a pipe through which the refrigerant flows and fins attached to the pipe will be described as an example.

The indoor fan 10a is a fluid transfer device that supplies air that exchanges heat with the refrigerant flowing through the second heat exchanger 4a to the second heat exchanger 4a. For example, the indoor fan 10a can be configured by a propeller fan having a plurality of blades. The indoor fan 10a is installed in a place where air can be supplied to the second heat exchanger 4a.

Each of the plurality of

second heat exchangers

4a and 4b has a predetermined heating capacity (kW) and cooling capacity (kW). The heating capacity and the cooling capacity can be defined using various parameters including the size of the

second heat exchangers

4a and 4b, the amount of air blown from the

indoor fans

10a and 10b, and the capacity of the compressor 1. The parameters used for defining the cooling capacity are not particularly limited. The plurality of

second heat exchangers

4a and 4b provided in the refrigeration cycle apparatus 100 may have the same heating capacity and cooling capacity or may be different from each other. This is the same even if the number of second heat exchangers is three or more.

FIG. 2 is a functional block diagram of the refrigeration cycle apparatus 100 according to the first embodiment. The control device 20 controls actuators such as the compressor 1, the outdoor fan 9, the

indoor fans

10a and 10b, the

expansion devices

3a and 3b, and the refrigerant flow switching device 6 that are provided in the refrigeration cycle apparatus 100. The control device 20 is connected to each actuator so that a control signal can be transmitted. Further, the control device 20 receives signals from the first temperature detector 5 and the timer 11. The control device 20 controls the actuator based on signals input from the first temperature detector 5 and the timer 11. Note that each of the

indoor units

40a and 40b may be provided with a remote controller that inputs the set temperature and the start and stop of the operation, and a signal from the remote controller may be input to the control device 20. The control device 20 performs a cooling operation, a heating operation, and a defrosting operation, which will be described later, based on the set temperature set for each of the

indoor units

40a and 40b and information on the start and stop of the operation.

The control device 20 includes a processing circuit 21 and a storage unit 22. The processing circuit 21 includes dedicated hardware or a CPU (also referred to as a central processing unit, a central processing unit, a processing unit, a processing unit, a microprocessor, a microcomputer, or a processor) that executes a program stored in a storage unit. The

When the processing circuit 21 is dedicated hardware, for example, a single circuit, a composite circuit, an ASIC (application specific integrated circuit), an FPGA (field-programmable gate array), or a combination of these corresponds to the processing circuit 21. To do. Each function realized by the processing circuit 21 may be realized by individual hardware, or each function may be realized by one piece of hardware.

When the processing circuit 21 is a CPU, each function executed by the processing circuit 21 is realized by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and stored in the internal memory of the processing circuit 21. The processing circuit 21 implements each function by reading and executing a program stored in the internal memory. The internal memory is a non-volatile or volatile semiconductor memory such as a program memory, EPROM, or EEPROM.

Note that a part of the function of the control device 20 may be realized by dedicated hardware, and a part may be realized by software or firmware. Although FIG. 2 shows that the control device 20 controls the actuators in an integrated manner, the control device 20 does not need to be physically configured as illustrated. That is, the specific form of distribution and integration of the control device 20 is not limited to the illustrated one, and all or a part thereof is functionally or physically distributed in arbitrary units according to various loads or usage conditions. Alternatively, they can be integrated. Moreover, although the control apparatus 20 can be installed in the outdoor unit 30, the specific arrangement | positioning of the control apparatus 20 is not limited. When the function of the control device 20 is realized by a plurality of control devices, the plurality of control devices may be distributed and arranged in each of the outdoor unit 30 and the plurality of

indoor units

40a and 40b.

The storage unit 22 stores at least the heating capacity information 22a. The heating capacity information 22a is information in which each of the plurality of

second heat exchangers

4a and 4b is associated with a predetermined heating capacity. The memory | storage part 22 memorize | stores the various threshold values which the control apparatus 20 uses for a control process other than the heating capability information 22a. The storage unit 22 is configured by, for example, a nonvolatile semiconductor memory.

<Operation of the refrigeration cycle apparatus 100>
The refrigeration cycle apparatus 100 of the present embodiment performs a cooling operation, a heating operation, and a defrosting operation. Hereinafter, the operation of the refrigeration cycle in each of the cooling operation, the heating operation, and the defrosting operation will be described together with the flow of the refrigerant.

(Cooling operation)
The cooling operation is an operation of supplying cooling air to the air-conditioning target space where the

indoor units

40a and 40b are installed. During the cooling operation, the refrigerant flow switching device 6 forms a refrigerant flow path in which the discharge side of the compressor 1 is connected to the first heat exchanger 2. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the first heat exchanger 2 functioning as a condenser via the refrigerant flow switching device 6. The refrigerant that has flowed into the first heat exchanger 2 is condensed by exchanging heat with the air sent from the outdoor fan 9 and becomes a low-temperature and high-pressure liquid refrigerant and flows out of the first heat exchanger 2.

The low-temperature and high-pressure liquid refrigerant that has flowed out of the first heat exchanger 2 flows in parallel into the

expansion devices

3a and 3b. The low-temperature and high-pressure liquid refrigerant that has flowed into the

expansion devices

3a and 3b is decompressed by the

expansion devices

3a and 3b to become a low-temperature and low-pressure liquid refrigerant or a two-phase refrigerant, and flows out from the

expansion devices

3a and 3b. The low-temperature and low-pressure refrigerant that has flowed out of the

expansion devices

3a and 3b flows into the

second heat exchangers

4a and 4b that function as evaporators. The refrigerant flowing into the

second heat exchangers

4a and 4b evaporates by exchanging heat with the air sent from the

indoor fans

10a and 10b and becomes a low-temperature and low-pressure gas refrigerant and flows out of the

second heat exchangers

4a and 4b. . By the heat exchange between the refrigerant and the air in the

second heat exchangers

4a and 4b, the refrigerant absorbs heat from the air, so that air for cooling the air-conditioning target space is generated.

The refrigerant that has flowed out of the

second heat exchangers

4a and 4b is sucked into the compressor 1 through the refrigerant flow switching device 6 and the accumulator 7. In the cooling operation, such a refrigeration cycle is repeated. In addition, execution and a stop of a cooling operation can also be switched for every some

indoor unit

40a, 40b. For example, when the indoor unit 40a performs a cooling operation and the indoor unit 40b stops the cooling operation, the expansion device 3a of the indoor unit 40a maintains a flow path with a predetermined opening through which the refrigerant passes, The expansion device 3b of the machine 40b closes the flow path so that the refrigerant does not flow into the second heat exchanger 4b. In this way, only a part of the plurality of

indoor units

40a and 40b can perform the cooling operation.

(Heating operation)
The heating operation is an operation of supplying heating air to the air-conditioning target space where the

indoor units

40a and 40b are installed. During the heating operation, the refrigerant flow switching device 6 forms a refrigerant flow path in which the discharge side of the compressor 1 is connected to the

second heat exchangers

4a and 4b. The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows in parallel into the

second heat exchangers

4a and 4b functioning as condensers via the refrigerant flow switching device 6. The refrigerant flowing into the

second heat exchangers

4a and 4b exchanges heat with the air sent from the

indoor fans

10a and 10b, condenses, and becomes a low-temperature and high-pressure liquid refrigerant and flows out from the

second heat exchangers

4a and 4b. . By the heat exchange between the refrigerant and the air in the

second heat exchangers

4a and 4b, the refrigerant radiates heat to the air, thereby generating heating air in the air-conditioning target space.

The low-temperature and high-pressure liquid refrigerant that has flowed out of the

second heat exchangers

4a and 4b flows into the

expansion devices

3a and 3b, respectively. The low-temperature and high-pressure liquid refrigerant that has flowed into the

expansion devices

3a and 3b is decompressed by the

expansion devices

3a and 3b flows into the first heat exchanger 2 that functions as an evaporator. The refrigerant that has flowed into the first heat exchanger 2 evaporates by exchanging heat with the air sent from the outdoor fan 9 and flows out of the first heat exchanger 2 as a low-temperature and low-pressure gas refrigerant.

The refrigerant that has flowed out of the first heat exchanger 2 is sucked into the compressor 1 through the refrigerant flow switching device 6 and the accumulator 7. In the heating operation, such a refrigeration cycle is repeated. In addition, execution and a stop of heating operation can also be switched for every some

indoor unit

40a, 40b. For example, when the indoor unit 40a performs the heating operation and the indoor unit 40b stops the heating operation, the expansion device 3a of the indoor unit 40a maintains a flow path with a predetermined opening through which the refrigerant passes, The expansion device 3b of the machine 40b closes the flow path so that the refrigerant does not flow into the second heat exchanger 4b. By doing in this way, heating operation can be performed only for some of a plurality of

indoor units

40a and 40b.

(Defrosting operation)
The defrosting operation is an operation for melting frost attached to the first heat exchanger 2 functioning as an evaporator during the heating operation. The defrosting operation of the present embodiment is realized by reversing the refrigerant flow during the heating operation, that is, by making the refrigerant flow the same as that during the cooling operation described above. However, during the defrosting operation, unlike the cooling operation, the control device 20 stops the operation of the

indoor fans

10a and 10b.

There are two types of defrosting operation of the present embodiment, a first defrosting operation and a second defrosting operation. The refrigerant flow is the same between the first defrosting operation and the second defrosting operation, but the conditions (timing) for starting the defrosting operation are different. Further, in the present embodiment, the first defrosting operation and the second defrosting operation have different times for the defrosting operation, and the second defrosting operation has a shorter operation time than the first defrosting operation. This will be specifically described below.

<Operation control of heating operation and defrosting operation>
FIG. 3 is a flowchart for explaining the heating operation and the defrosting operation of the refrigeration cycle apparatus 100 according to the first embodiment. With reference to FIG. 3, the control which the control apparatus 20 performs in heating operation and defrost operation is demonstrated.

When the heating operation is started (S1), the control device 20 determines whether or not the ambient temperature of the first heat exchanger 2 belongs to a temperature range between TH2 and TH1 based on the detection value of the first temperature detector 5. To detect. Here, the relationship TH2 <TH1 is satisfied. The temperature TH1 is, for example, 5 ° C., and the temperature TH2 is, for example, −3 ° C. Specific numerical values of the temperature TH1 and the temperature TH2 are not limited to those exemplified here, but the upper limit value and the lower limit value of the temperature range in which the amount of frost formation on the first heat exchanger 2 is likely to increase are the temperature TH1 and the temperature, respectively. TH2 is determined in advance and stored in the storage unit 22.

If the ambient temperature of the first heat exchanger 2 does not belong to the temperature range of TH2 or more and TH1 or less (S2; NO), the process proceeds to step S8, and if it belongs (S2; YES), a plurality of second It is detected whether or not the total heating capacity ΣQ _j of the

heat exchangers

4a and 4b during the heating operation is not less than a first value Q that is a predetermined threshold value. As described above, the plurality of

indoor units

40a and 40b provided in the refrigeration cycle apparatus 100 of the present embodiment can be set to execute and stop the heating operation individually. Therefore, the control device 20 calculates the total heating capacity ΣQ _j by adding the heating capacities of the

second heat exchangers

4a and 4b of the

indoor units

40a and 40b that are performing the heating operation, and the total heating capacity The process of step S3 is executed by comparing ΣQ _j with the first value Q. The control device 20 calculates the total heating capacity ΣQ _j based on the heating capacity information 22 a stored in the storage unit 22.

When the total heating capacity ΣQ _j is greater than or equal to the first value Q (S3; YES), the process proceeds to step S4, and when it is less than the first value Q (S3; NO), the process proceeds to step S8.

Next, the processing after step S8 will be described which proceeds when NO in step S2 and NO in step S3. In step S8, the control device 20 detects whether or not the heating operation time is equal to or longer than a first operation time T11 that is a predetermined threshold value (S8). Although the definition of heating operation time is not specifically limited, In this Embodiment, the operation time of the compressor 1 in heating operation is made into heating operation time. The control device 20 measures the operation time of the compressor 1 after starting the heating operation with the timer 11, and compares the measured time with the first operation time T11 to execute the process of step S8. The value of the first operating time T11 is, for example, 50 minutes, but is not limited to this value.

In step S8, when the heating operation time has reached the first operation time T11, the control device 20 starts the first defrosting operation (S9). When the first defrosting operation is started, the control device 20 controls the refrigerant flow switching device 6 as described above to connect the refrigerant flow discharged from the compressor 1 to the first heat exchanger 2. To do. By doing in this way, the high temperature refrigerant | coolant discharged from the compressor 1 is supplied to the 1st heat exchanger 2, and the frost adhering to the 1st heat exchanger 2 is melted.

While the operation time of the first defrosting operation is less than the predetermined defrosting time T1 (S10: NO), the control device 20 continues the first defrosting operation, and the operation time of the first defrosting operation is defrosted. If it becomes more than time T1 (S10: YES), the control apparatus 20 will complete | finish a 1st defrost driving | operation (S11). When the first defrosting operation is finished, the control device 20 starts the heating operation (S1). Here, in the present embodiment, the defrosting time T1 of the first defrosting operation can be longer than the defrosting time T2 of the second defrosting operation described later. Although a specific numerical value is not limited, the defrosting time T1 is, for example, 12 minutes.

Next, the processing after step S4 that proceeds when YES is determined in step S3 will be described. In step S4, the control device 20 detects whether the heating operation time is equal to or longer than a second operation time T12 that is a predetermined threshold (S4). Although the definition of heating operation time is not specifically limited, In this Embodiment, the operation time of the compressor 1 in heating operation is made into heating operation time. The control device 20 measures the operation time of the compressor 1 after starting the heating operation with the timer 11, and compares the measured time with the second operation time T12 to execute the process of step S4. The value of the second operation time T12 is shorter than the first operation time T11 shown in step S8. Although a specific numerical value is not limited, the second operation time T12 is, for example, 40 minutes.

In step S4, when the heating operation time becomes equal to or longer than the second operation time T12, the control device 20 starts the second defrosting operation (S5). When the second defrosting operation is started, the control device 20 controls the refrigerant flow switching device 6 as described above to connect the refrigerant flow discharged from the compressor 1 to the first heat exchanger 2. To do. By doing in this way, the high temperature refrigerant | coolant discharged from the compressor 1 is supplied to the 1st heat exchanger 2, and the frost adhering to the 1st heat exchanger 2 is melted.

While the operation time of the second defrosting operation is less than the predetermined time T2 (S6: NO), the control device 20 continues the second defrosting operation, and the operation time of the second defrosting operation is the defrosting time T2. (S6: YES), the control device 20 ends the second defrosting operation (S7). When the second defrosting operation is finished, the control device 20 starts the heating operation (S1). Here, the defrosting time T2 of the second defrosting operation may be shorter than the defrosting time T1 of the first defrosting operation. Although the specific numerical value is not limited, the time T2 is, for example, 4 minutes.

<Operation of heating operation and defrosting operation>
The operation of the heating operation and the defrosting operation of the refrigeration cycle apparatus 100 of the present embodiment will be described with reference to FIGS. 4 and 5 and the above-described FIG. FIG. 4 is a diagram illustrating the integrated heating capacity of the first defrosting operation according to the first embodiment. FIG. 5 is a diagram illustrating the integrated heating capacity of the second defrosting operation according to the first embodiment. The vertical axis in FIGS. 4 and 5 indicates the heating capacity of the

second heat exchangers

4a and 4b during the heating operation, and the horizontal axis indicates the time. 2 conceptually shows the change in heating capacity through defrosting operation.

As shown in FIG. 3, in the present embodiment, during the heating operation, the ambient temperature of the first heat exchanger 2 functioning as an evaporator and the total heating capacity of the

second heat exchangers

4a and 4b during the heating operation. Based on ΣQ _j , either the first defrosting operation or the second defrosting operation is selected, and the heating operation is started when the first defrosting operation is selected and when the second defrosting operation is selected. Then, the heating operation time from the start of the defrosting operation is varied. Here, as described with reference to FIG. 3, the ambient temperature of the first heat exchanger 2 is within a temperature range in which the amount of frost formation tends to increase (step S2; YES), and the second heat exchange during the heating operation is performed. A condition including that the total heating capacity ΣQ _j of the

devices

4a and 4b is equal to or greater than the first value Q is referred to as a first condition.

First, the operation of the heating operation and the first defrosting operation that are performed when the above-described first condition is not satisfied will be described. When the first condition is not satisfied during the heating operation, the heating operation is interrupted and the first defrosting operation is started when the heating operation time is equal to or longer than the first operation time T11 longer than the second operation time T12.

As shown in FIG. 4, when the heating operation is started, the heating capacity increases and reaches a peak, and the heating capacity gradually decreases as the operation time elapses. The decrease in the heating capacity is caused mainly by a decrease in the heat exchange efficiency of the first heat exchanger 2 due to frost adhering to the first heat exchanger 2. When the first condition is not satisfied, that is, the ambient temperature of the first heat exchanger 2 is in a temperature range in which the amount of frost formation is difficult to increase, or the total heating capacity of the

second heat exchangers

4a and 4b during the heating operation If ΣQ _j is relatively small and the heat exchange load of the first heat exchanger 2 is also small, it can be said that frost is relatively difficult to adhere to the first heat exchanger 2. For this reason, time T11 of heating operation is lengthened compared with the case where 2nd defrost operation is performed.

In the example shown in FIG. 4, the first defrosting operation is started with the heating capacity during heating operation being 75% (average). Here, the heating capability over the period consisting of the heating operation and the subsequent defrosting operation is defined as the integrated heating capability. Since the heating capacity becomes substantially zero during the first defrosting operation, the integrated heating capacity over the period consisting of the heating operation and the subsequent first defrosting operation is 60% in the example of FIG. ing. When performing the first defrosting operation, since the heating operation time per time is relatively long, the user is given an unpleasant feeling due to switching between the heating operation and the defrosting operation in a relatively short time. Hateful.

Next, the operation of the heating operation and the second defrosting operation that are performed when the first condition described above is satisfied will be described. When the first condition is satisfied during the heating operation, the heating operation is interrupted and the second defrosting operation is started when the heating operation time reaches a second operation time T12 that is shorter than the first operation time T11.

As shown in FIG. 5, when the heating operation is started, the heating capacity increases and reaches a peak, and the heating capacity gradually decreases as the operation time elapses. The decrease in the heating capacity is caused mainly by a decrease in the heat exchange efficiency of the first heat exchanger 2 due to frost adhering to the first heat exchanger 2. In the present embodiment, when the first condition is satisfied, that is, the ambient temperature of the first heat exchanger 2 is in a temperature range in which the amount of frost formation tends to increase, and the

second heat exchangers

4a and 4b in the heating operation When the total heating capacity ΣQ _j is relatively large and the heat exchange load of the first heat exchanger 2 is also large, the heating operation is interrupted in a relatively short time and the second defrosting operation is started. Thus, by shortening the heating operation time, the defrosting operation can be started before the amount of frost formation on the first heat exchanger 2 becomes excessive. And since the defrosting operation is started in a state where the amount of frost on the first heat exchanger 2 is relatively small, the second defrosting operation time can be shortened.

In the example shown in FIG. 5, the second defrosting operation is started in a state where the heating capacity during the heating operation is 80% (average). During the second defrosting operation, the heating capacity becomes substantially zero. However, since the time of the second defrosting operation may be short as described above, in the example of FIG. A cumulative heating capacity of 70% is obtained throughout the period of the defrosting operation. Furthermore, since the time for the second defrosting operation is relatively short, the inclination of the rising of the heating capacity in the heating operation performed after the second defrosting operation is large, and the heating capacity can be reduced in a shorter time than in the case of FIG. Can be raised.

As described above, the refrigeration cycle apparatus 100 of the present embodiment includes the compressor 1, the first heat exchanger 2, the plurality of

expansion devices

3a and 3b, and the plurality of

second heat exchangers

4a and 4b. ing. Then, during the heating operation in which the first heat exchanger 2 functions as an evaporator and at least a part of the plurality of

second heat exchangers

4a and 4b functions as a condenser, the surroundings of the first heat exchanger 2 The temperature is detected, the ambient temperature of the first heat exchanger 2, the total heating capacity of the plurality of

second heat exchangers

4a and 4b functioning as a condenser, and the operation time of the heating operation, Based on the above, one of the first defrosting operation and the second defrosting operation is selected. When the first defrosting operation is selected, the first defrosting operation is started when the operation time of the heating operation reaches the first operation time, and when the second defrosting operation is selected, the operation of the heating operation is started. When the time reaches the second operation time shorter than the first operation time, the second defrosting operation is started. Thus, based on the ambient temperature of the 1st heat exchanger 2 which functions as a condenser, and the total value of the heating capacity of the

2nd heat exchangers

4a and 4b which function as an evaporator, the operation time of heating operation is reduced. Start the defrosting operation in different ways. For this reason, compared with the case where a defrost operation is started based on an empirical rule from the temperature of the heat exchanger used as a defrost object, the actual frosting state to the 1st heat exchanger 2 used as a defrost object is The defrosting operation can be started at a more reflected timing. Therefore, it is possible to suppress a decrease in the integrated heating capacity in a period including a set of heating operations and a defrosting operation that are continuously executed. In addition, after the second defrosting operation in which the operation time is relatively short, it is possible to shorten the time required for starting up the heating operation that is subsequently performed.

Further, in the refrigeration cycle apparatus 100 of the present embodiment, the detection value of the first temperature detector 5 that detects the ambient temperature of the first heat exchanger 2 is within the first temperature range, and the total value of the heating capacity When is greater than or equal to the first value, the second defrosting operation with a relatively short time is selected. Therefore, when the amount of frost on the first heat exchanger 2 that is a defrost target is likely to increase, the heating operation can be interrupted early and the second defrost operation can be started. It is possible to suppress a decrease in the integrated heating capacity during a period including a set of heating operation and defrosting operation that are performed.

Embodiment 2. FIG.
In this Embodiment, the 2nd temperature detector 12 which detects the surface temperature of the 1st heat exchanger 2 which functions as an evaporator at the time of heating operation and functions as a condenser at the time of defrosting operation is provided, and heating operation and defrosting are provided. The detected value of the second temperature detector 12 is used in operation control. In the present embodiment, the description will be focused on differences from the first embodiment.

FIG. 6 is a diagram illustrating an example of a circuit configuration of the refrigeration cycle apparatus 100A according to the second embodiment. In the refrigeration cycle apparatus 100 of the present embodiment, a second temperature detector 12 that detects the surface temperature of the first heat exchanger 2 is provided. The 2nd temperature detector 12 detects the surface temperature of the 1st heat exchanger 2 which reflects the frost formation state to the 1st heat exchanger 2 directly or indirectly. For example, the second temperature detector 12 can detect the surface temperature of the pipes constituting the first heat exchanger 2. In addition, the second temperature detector 12 may detect the temperature of the refrigerant flowing in the first heat exchanger 2 and detect the surface temperature of the first heat exchanger 2 based on the temperature of the refrigerant. The configuration other than the second temperature detector 12 is the same as that shown in the first embodiment.

FIG. 7 is a functional block diagram of the refrigeration cycle apparatus 100A according to the second embodiment. The control device 20 is connected to the second temperature detector 12 so that signals can be transmitted and received. The control device 20 controls the actuator based on the signal input from the second temperature detector 12 in addition to the signal input from the first temperature detector 5 and the timer 11.

FIG. 8 is a flowchart illustrating the heating operation and the defrosting operation of the refrigeration cycle apparatus 100A according to the second embodiment. The heating operation and the defrosting operation of the present embodiment are different from the first embodiment in the condition for starting the first defrosting operation and the condition for ending the first defrosting operation. Specifically, the flowchart shown in FIG. 8 is different from the flowchart shown in FIG. 3 of Embodiment 1 in that the processing content of step S8A and step S12A are added. Hereinafter, the difference from FIG. 3 will be mainly described.

If NO in step S2 and NO in step S3, that is, if the first defrosting operation is selected instead of the second defrosting operation, the process proceeds to step S8A. In step S8A, control device 20 detects whether the heating operation time is equal to or longer than a predetermined first operation time T11. Further, the control device 20 determines whether or not the surface temperature of the first heat exchanger 2 is equal to or lower than a first temperature TH3 that is a predetermined threshold, based on the detection value of the second temperature detector 12. To do. Here, the first temperature TH3 is a temperature for determining the amount of frost formation on the first heat exchanger 2, and the temperature estimated that the amount of frost formation on the first heat exchanger 2 is likely to increase. Are stored in the storage unit 22 in advance. The first temperature TH3 is preferably a temperature lower than the temperature TH2 in step S2, and is, for example, −10 ° C. although a specific numerical value is not limited.

When the heating operation time is equal to or longer than the first operation time T11 and the surface temperature of the first heat exchanger 2 is equal to or lower than the first temperature TH3 that is set in advance (S8A; YES), the control device 20 performs the first defrosting. Operation is started (S9).

During the first defrosting operation, the control device 20 ends the first defrosting operation when the surface temperature of the first heat exchanger 2 becomes equal to or higher than a second temperature TH4 that is a predetermined threshold (S12A; YES). To do. Here, 2nd temperature TH4 is the temperature for determining the amount of frost formation to the 1st heat exchanger 2, and the temperature estimated that defrosting of the 1st heat exchanger 2 was completed is memorized beforehand. Stored in the unit 22. Although the specific value of the second temperature TH4 is not limited, it is 10 ° C., for example. When the surface temperature of the first heat exchanger 2 is lower than the second temperature TH4 which is a predetermined threshold (S12A; NO), the control device 20 proceeds to step S10. The processing after step S10 is the same as that described in FIG.

Thus, in this embodiment, the same configuration as that described in the first embodiment is provided, and the same effect as in the first embodiment can be obtained. Furthermore, in the refrigeration cycle apparatus 100A of the present embodiment, when the first defrosting operation is selected, the operation time of the heating operation becomes equal to or longer than the first operation time, and the surface temperature of the first heat exchanger 2 is the first. When the temperature is equal to or lower than 1 temperature TH3, the first defrosting operation is started. Since the first defrosting operation is started based on the surface temperature of the first heat exchanger 2 in which the frosting state on the first heat exchanger 2 is reflected in addition to the operation time of the heating operation, defrosting is necessary. The first heat exchanger 2 can be defrosted by more accurately detecting the timing.

The refrigeration cycle apparatus 100A of the present embodiment ends the first defrosting operation when the surface temperature of the first heat exchanger 2 becomes equal to or higher than the second temperature TH4 during the first defrosting operation. Since the end timing of the first defrosting operation is determined based on the temperature of the first heat exchanger 2 in which the defrosting state of the first heat exchanger 2, that is, the defrosting state is reflected, the defrosting is insufficient or excessive. Defrosting operation can be suppressed.

In step S2 of FIG. 3 and FIG. 8, and step S8A and step S12A of FIG. 8, the condition is satisfied when the condition that satisfies the condition for determining the magnitude relationship with the threshold value is satisfied for a predetermined time. The determination may be made to proceed to the next step. In the example of step S8A in FIG. 8, the control device 20 determines whether or not the surface temperature of the first heat exchanger 2 is equal to or lower than the first temperature TH3. You may determine with the surface temperature of the 1st heat exchanger 2 being below 1st temperature TH3, when time, for example, 3 minutes or more pass. The same applies to step S12A, and when the state where the surface temperature of the first heat exchanger 2 is equal to or higher than the second temperature TH4 has elapsed for a predetermined time, for example, 3 minutes or more, the process proceeds to the next step. The detection values output from the first temperature detector 5 and the second temperature detector 12 may vary due to disturbances or the like. However, the detection values described above are determined based on the detection values over a predetermined time. Misjudgments caused by variations can be reduced.

Further, in the heating operation shown in FIGS. 3 and 8, the operation frequency of the compressor 1 may be varied according to the ambient temperature of the first heat exchanger 2 functioning as an evaporator. For example, when a table for controlling the frequency of the compressor 1 according to the ambient temperature of the first heat exchanger 2 is stored in the storage unit 22 in advance, and the ambient temperature of the first heat exchanger 2 is low, The operating frequency of the compressor 1 is controlled to a large value as compared with the case where it is high. By doing in this way, the fall of heating capability is suppressed.

Further, the refrigeration cycle apparatus and the defrosting operation method of the refrigeration cycle apparatus shown in the first and second embodiments can be applied not only to an air conditioner but also to an apparatus using another refrigeration cycle such as a refrigerator. Further, in

Embodiments

1 and 2, the so-called reverse cycle defrosting operation in which the refrigerant is circulated in the direction opposite to that in the heating operation has been described as an example, but the specific configuration of the defrosting operation is not limited thereto. . The processing related to the selection, start and end of the first defrosting operation and the second defrosting operation described in the first and second embodiments is performed by other specific configurations such as a defrosting operation using a heater or hot water. It can also be combined with frost operation. For example, the first defrosting operation shown in the first and second embodiments and the air conditioning apparatus dedicated to heating that does not have the configuration corresponding to the refrigerant flow switching device 6 and the refrigerant flows in one direction Processing related to selection, start, and end of the second defrosting operation can be applied.

1 compressor, 2 first heat exchanger, 3a expansion device, 3b expansion device, 4a second heat exchanger, 4b second heat exchanger, 5 first temperature detector, 6 refrigerant flow switching device, 7 accumulator, 8 check valve, 9 outdoor fan, 10a indoor fan, 10b indoor fan, 11 timer, 12 second temperature detector, 20 control device, 21 processing circuit, 22 storage unit, 22a heating capacity information, 30 outdoor unit, 40a indoor Machine, 40b indoor unit, 100 refrigeration cycle apparatus, 100A refrigeration cycle apparatus.

Claims

A compressor,
A first heat exchanger;
A plurality of diaphragm devices;
A plurality of second heat exchangers;
A first temperature detector for detecting an ambient temperature of the first heat exchanger;
A storage unit for storing the heating capacity of each of the plurality of second heat exchangers;
A controller for performing a heating operation in which the first heat exchanger functions as an evaporator and at least a part of the plurality of second heat exchangers functions as a condenser;
The control device includes:
During the heating operation, based on a detection value of the first temperature detector and a total value of heating capacity of the plurality of second heat exchangers functioning as the condenser, a first defrosting is performed. Select either operation or second defrost operation,
When the first defrosting operation is selected, the first defrosting operation is started when the operation time of the heating operation reaches the first operation time, and when the second defrosting operation is selected, the heating is performed. The refrigeration cycle apparatus that starts the second defrosting operation when the operation time of the operation reaches a second operation time shorter than the first operation time.
The control device includes:
When the first condition is not satisfied, the first defrosting operation is selected,
The second defrosting operation is selected when the first condition is satisfied,
The refrigeration cycle apparatus according to claim 1, wherein the first condition includes that a detection value of the first temperature detector is within a first temperature range, and a total value of the heating capacity is equal to or greater than a first value. .
A second temperature detector for detecting a surface temperature of the first heat exchanger;
When the control device selects the first defrosting operation, the operation time of the heating operation reaches the first operation time, and the detection value of the second temperature detector is equal to or lower than the first temperature. The refrigeration cycle apparatus according to claim 1 or 2, wherein the first defrosting operation is started.
A second temperature detector for detecting a surface temperature of the first heat exchanger;
The control device ends the first defrosting operation and starts the heating operation when a detection value of the second temperature detector becomes equal to or higher than a second temperature during the execution of the first defrosting operation. The refrigeration cycle apparatus according to any one of claims 1 to 3.
The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein a time of the second defrosting operation is shorter than a time of the first defrosting operation.
A defrosting operation method for a refrigeration cycle apparatus including a compressor, a first heat exchanger, a plurality of expansion devices, and a plurality of second heat exchangers,
During the heating operation in which the first heat exchanger functions as an evaporator and at least some of the plurality of second heat exchangers function as condensers,
Detecting the ambient temperature of the first heat exchanger;
Based on the ambient temperature of the first heat exchanger and the total heating capacity of the plurality of second heat exchangers functioning as the condenser, the first defrosting operation and the second defrosting are performed. Select either driving or
When the first defrosting operation is selected, the first defrosting operation is started when the operation time of the heating operation reaches the first operation time, and when the second defrosting operation is selected, the heating is performed. The defrosting operation method of the refrigeration cycle apparatus, wherein the second defrosting operation is started when the operation time of the operation reaches a second operation time shorter than the first operation time.
In the step of selecting either the first defrosting operation or the second defrosting operation,
When the first condition is not satisfied, the first defrosting operation is selected,
When the first condition is satisfied, the second defrosting operation is selected,
The refrigeration cycle apparatus according to claim 6, wherein the first condition includes that an ambient temperature of the first heat exchanger is within a first temperature range, and a total value of the heating capacity is equal to or higher than a first value. Defrosting operation method.
When the first defrosting operation is selected, when the operation time of the heating operation reaches the first operation time and the surface temperature of the first heat exchanger becomes equal to or lower than the first temperature, the first The defrosting operation method of the refrigeration cycle apparatus according to claim 6 or 7, wherein the defrosting operation is started.
During the first defrosting operation, when the surface temperature of the first heat exchanger becomes equal to or higher than the second temperature, the first defrosting operation is terminated.
The defrosting operation method for a refrigeration cycle apparatus according to any one of claims 6 to 8, wherein the heating operation is started after the first defrosting operation is completed.
The defrosting operation method for a refrigeration cycle apparatus according to any one of claims 6 to 9, wherein a time of the second defrosting operation is shorter than a time of the first defrosting operation.