JP2011127775A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable air conditioner capable of performing defrosting operation and continuously achieving comfortable heating operation. <P>SOLUTION: In the air conditioner 100, when the defrosting operation, wherein a refrigerant discharged from a compressor 1 is made to flow toward a heat source side heat exchanger 41 to thaw frost sticking to the heat source side heat exchanger 41, is carried out during heating operation, the refrigerant passing through the heat source side heat exchanger 41 is made to flow to a load side unit in a thermo-off or stopping condition among a plurality of load side units. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air conditioner equipped with a refrigeration cycle and capable of performing a defrosting operation.

  In an air conditioner equipped with a refrigeration cycle, a heat source unit (outdoor unit) is in a heating operation (all driving load-side units (indoor units) are in a full heating operation in which a heating operation is performed or is driven) When performing a heating main operation with a larger heating load in the load side unit, the pipe (heat transfer pipe) disposed in the heat source side heat exchanger (outdoor heat exchanger) serving as an evaporator is connected to a low temperature The refrigerant will pass through. Then, in the heat source side heat exchanger, heat exchange between the low-temperature refrigerant and the air supplied from the blowing means is performed via the pipe, and moisture in the air forms the heat source side heat exchanger. Frozen when condensed with the fins or pipes.

  When frost accumulates (frosting), heat exchange with air is not performed well, so the heating capacity in the heat source machine (the amount of heat per hour supplied to the load unit (hereinafter including the cooling capacity) is simply Called capacity)). If it becomes like this, there exists a possibility that it may become impossible to supply desired capacity | capacitance with respect to the air-conditioning load (The amount of heat which a load side unit requires (henceforth only load)) in a load side unit. Therefore, conventionally, in order to remove frost adhering to the heat source side heat exchanger during the heating operation, the air conditioning in which the defrosting operation can be performed on the heat source device (or each heat source device when there are multiple heat source devices). An apparatus exists (see, for example, Patent Document 1).

  There is also an air conditioner including a plurality of load-side units and capable of simultaneous cooling and heating operation (mixed cooling and heating operation) (for example, see Patent Document 2). In such an air conditioner, for example, according to the set temperature set via a remote controller provided to the load side unit and the temperature around the load side unit, cooling and heating are performed in the plurality of load side units, respectively. Can be done at the same time. In such an air conditioner, the heat source unit and the load side unit are often connected by two refrigerant pipes via a relay unit. In the defrosting operation, a high-temperature and high-pressure gas refrigerant is allowed to flow through the heat source side heat exchanger, the refrigerant is condensed to perform defrosting, and the refrigerant is not passed through the load side unit, but is transferred to the heat source machine via the relay unit. If you return it, you can execute it.

Japanese Patent Application Laid-Open No. 07-332815 (see each example) JP-A-8-261599 (page 4, FIG. 1 etc.)

  When performing the defrosting operation with an air conditioner as described in Patent Document 2, liquid refrigerant discharged from the compressor and condensed in the heat source side heat exchanger is routed through a bypass pipe inside the relay unit. The refrigerant may be flown so as to bypass the load side unit. However, in this flow, heat collection from the load side unit including the piping cannot be expected. That is, the liquid condensed in the heat source side heat exchanger cannot be evaporated by using the heat of the load side unit or the heat of the piping heated for heating.

  As a result, during the defrosting operation, there is a possibility that the liquid back amount to the accumulator becomes excessive and the liquid refrigerant overflows from the accumulator, or the low pressure is drawn and the unit is stopped by the low pressure protection. . In addition, it may take time to return to the original heating state after the defrosting operation. In order to avoid these conditions, heat is collected from the load-side unit. Therefore, when liquid refrigerant is flowed to the load-side unit during the defrosting operation, the sound of the refrigerant flowing from the load-side unit is Even when the fan is stopped at the side unit, there is a problem that cold air enters the room and the room temperature is lowered or the user feels uncomfortable.

  This invention was made in order to solve said subject, and it aims at providing the air conditioning apparatus which can perform defrost operation which can implement | achieve a reliable heating operation with high reliability continuously. Yes.

  An air conditioner according to the present invention includes at least one heat source unit on which at least a compressor and a heat source side heat exchanger are mounted, and at least two load side units on which at least an expansion device and a load side heat exchanger are mounted. And at least one relay unit that is interposed between the heat source unit and the load side unit and switches the refrigerant flow path to supply the heat or cold generated by the heat source unit to the load side heat exchanger. And when the defrosting operation is performed in which the refrigerant discharged from the compressor is caused to flow through the heat source side heat exchanger and the frost adhering to the heat source side heat exchanger is melted during the heating operation. The refrigerant that has passed through the side heat exchanger is caused to flow to a load-side unit that is thermo-off or stopped among the plurality of load-side units.

  According to the air conditioning apparatus of the present invention, since the refrigerant is caused to flow through the load-side unit that is thermo-off or stopped during the defrosting operation, comfortable heating can be continuously realized.

It is a schematic block diagram which shows an example of the refrigerant circuit structure of the air conditioning apparatus which concerns on embodiment of this invention. It is a flowchart which shows the flow of a process at the time of determining the flow of the refrigerant | coolant at the time of the defrost driving | operation of the air conditioning apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an example of a refrigerant circuit configuration of an air-conditioning apparatus 100 according to an embodiment of the present invention. Based on FIG. 1, the refrigerant circuit structure and operation | movement of the air conditioning apparatus 100 are demonstrated. The air conditioner 100 is installed in a building, a condominium, or the like, and can supply a cooling load and a heating load simultaneously using a refrigeration cycle (heat pump cycle) that circulates a refrigerant. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  The air conditioner 100 includes a heat source unit A, three load-side units (load-side unit B, load-side unit C, load-side unit D) in charge of cooling load or heating load, and a relay E. is doing. Among these, the load side unit B, the load side unit C, and the load side unit D are connected to the heat source unit A in parallel. And the relay machine E is installed between the heat source machine A and the three load side units, and the flow of the refrigerant is switched by the relay machine E, so that the cooling operation or the heating operation is performed in each of the three load side units. Is supposed to be executed. In the air conditioner 100, the heat source unit A and each load side unit are connected by two pipes via the relay unit E.

[Heat source machine A]
In the heat source machine A, a compressor 1, a four-way valve 2 that is a flow path switching unit, a heat source side heat exchanging unit 3, and an accumulator 4 are connected and mounted in series. This heat source machine A has a function of supplying cold or hot energy to the three load-side units. In addition, the heat source device A is equipped with a heat source side flow switching device 40 that can make the flow of the refrigerant flowing into the relay device E in a certain direction regardless of the request of the load side unit. Further, the heat source device A is provided with a heat source side blower 20 such as a fan for supplying air to the heat source side heat exchanging unit 3.

  The compressor 1 sucks the refrigerant and compresses the refrigerant to a high temperature / high pressure state, and may be composed of, for example, an inverter compressor capable of capacity control. The four-way valve 2 is provided on the discharge side of the compressor 1 and switches between a refrigerant flow during the heating operation and a heat source side refrigerant flow during the cooling operation. The accumulator 4 is provided on the suction side of the compressor 1 and stores excess refrigerant. The heat source side heat exchange unit 3 will be described in detail later.

  The heat source side flow path switching device 40 includes two pipes (pipe 60, pipe 70) and four check valves (first check valve 32, second check valve 33, third check valve 34, first check valve 34, 4 check valves 35). The pipe 60 connects the second connection pipe 7 on the upstream side of the first check valve 32 and the heat source side first connection pipe 6 on the upstream side of the second check valve 33. The pipe 70 connects the heat source side second connection pipe 7 on the downstream side of the first check valve 32 and the heat source side first connection pipe 6 on the downstream side of the second check valve 33.

  The first check valve 32 is provided between the connection portions of the pipe 60 and the pipe 70 in the heat source side second connection pipe 7, and refrigerant is supplied only in a predetermined direction (direction from the heat source machine A to the relay machine E). It allows flow. The second check valve 33 is provided between the connection portions of the pipe 60 and the pipe 70 in the heat source side first connection pipe 6, and refrigerant is supplied only in a predetermined direction (direction from the relay E to the heat source A). It allows flow. The third check valve 34 is provided in the pipe 70 and allows the refrigerant to flow only from the downstream side of the second check valve 33 to the downstream side of the first check valve 32. The fourth check valve 35 is provided in the pipe 60 and allows the refrigerant to flow only from the upstream side of the second check valve 33 to the upstream side of the first check valve 32.

  The configuration of the heat source side heat exchange unit 3 will be described in more detail. The heat source side heat exchanging unit 3 includes two heat source side heat exchangers (a first heat source side heat exchanger 41 and a second heat source side heat exchanger 42) connected in parallel and before and after each heat source side heat exchanger. Bypass the four electromagnetic on-off valves (first electromagnetic on-off valve 44, second electromagnetic on-off valve 45, third electromagnetic on-off valve 46, fourth electromagnetic on-off valve 47) and two heat source side heat exchangers The heat source side bypass pipe 43, the fifth electromagnetic opening / closing valve 48 provided in the heat source side bypass pipe 43, and the heat source side blower 20 are configured. In addition, it is good also as one heat source side heat exchanger, without dividing | segmenting the heat source side heat exchanger provided in the heat source side heat exchange part 3. FIG.

  The two heat source side heat exchangers function as an evaporator during heating operation, function as a condenser (radiator) during cooling operation, and exchange heat between the air supplied from the heat source side blower 20 and the refrigerant. The refrigerant is vaporized or condensed and liquefied. The four electromagnetic open / close valves are paired with respect to each heat source side heat exchanger, and are controlled to open and close to allow refrigerant to flow into and out of each heat source side heat exchanger. The heat source side bypass pipe 43 is connected to the side that is not the connection side of the heat source side heat exchanger of the four electromagnetic on-off valves so that the refrigerant bypasses the two heat source side heat exchangers. The fifth electromagnetic on-off valve 48 allows the refrigerant to flow into and out of the heat source side bypass pipe 43 by controlling the opening and closing.

  Further, the heat source machine A is provided with a first pressure sensor 18 for detecting the pressure of the refrigerant discharged from the compressor 1. Although not shown, a pressure sensor that detects the pressure of the refrigerant sucked into the compressor 1, a temperature sensor that detects the temperature of the refrigerant discharged from the compressor 1, and a refrigerant that is sucked into the compressor 1 A temperature sensor for detecting the temperature, a temperature sensor for detecting the temperature of the refrigerant flowing into and out of the heat source side heat exchanging unit 3, a temperature sensor for detecting the temperature of the outside air taken in by the heat source side blower 20, and the like may be provided.

  Information (temperature information and pressure information) detected by these various detection means is sent to a control means (not shown) that controls the operation of the air conditioner 100, and the driving frequency of the compressor 1 and the heat source side blower 20 Rotation speed, switching of the four-way valve 2, opening / closing of the first electromagnetic on / off valve 44, second electromagnetic on / off valve 45, third electromagnetic on / off valve 46, fourth electromagnetic on / off valve 47 and fifth electromagnetic on / off valve 48, relay E Switching of the refrigerant flow path through the provided switching devices (switching device 8b, switching device 8c, switching device 8d), the opening degree of the second flow control device 13, the opening degree of the third flow control device 15, and the load This is used for controlling the opening degree of the first flow rate control device 9 provided in the side unit.

[Load side unit]
Each load side unit is mounted with a load side heat exchanger (indoor heat exchanger) 5 and a first flow rate control device 9 connected in series. Each load-side unit has a function of receiving cooling or heating supply from the heat source device A and taking charge of cooling load or heating load. A load-side fan such as a fan for supplying air to the load-side heat exchanger 5 may be provided in the vicinity of the load-side heat exchanger 5. However, the load-side heat exchanger 5 is not limited to the one that performs heat exchange between the refrigerant and air, and performs heat exchange between the refrigerant and a heat medium different from the refrigerant such as water. Also good.

  The load-side heat exchanger 5 functions as a condenser (heat radiator) during heating operation, functions as an evaporator during cooling operation, and exchanges heat between air and refrigerant supplied from a load-side fan (not shown). The refrigerant is condensed or liquefied or vaporized. The 1st flow control device 9 has a function as a pressure-reduction valve or an expansion valve, and decompresses and expands a refrigerant. The first flow rate control device 9 may be configured by a device whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like.

[Repeater E]
The relay E includes a gas-liquid separator 12, a first heat exchange unit 19, a second flow rate control device 13, a second heat exchange unit 16, a third flow rate control device 15, and a first branch unit 10. And the 2nd branch part 11 is mounted. The relay E connects each of the load side units and the heat source unit A, and controls the switching devices (the switching device 8b, the switching device 8c, and the switching device 8d) of the first branching unit 10 to thereby control the load side heat. It has a function of switching the flow of refrigerant flowing into each of the exchangers.

  The relay E is connected to the heat source machine A by two heat source side connection pipes (the heat source side first connection pipe 6 and the heat source side second connection pipe 7), and two load side connection pipes (load side first connection). The pipe 6b, the load side second connection pipe 6c, and the load side third connection pipe 6d) are connected to each of the load side units. Further, the relay E has a downstream side of the primary side of the second heat exchanging unit 16 (the side on which the refrigerant through which the refrigerant that has passed through the second flow rate control device 13 and the refrigerant that has flowed out of the second branching unit 11 flow) flows. The first bypass pipe 14 branched from the pipe on the side and connected to the first connection pipe 6 on the heat source side, and the sixth check valve (sixth check valve 52b, sixth check valve 52c) of the second branch portion 11 , A sixth check valve 52d), a second flow rate control device 13, and a second bypass pipe 51 connecting the upstream side on the primary side of the second heat exchange unit 16 is provided.

  The gas-liquid separation device 12 is provided on the downstream side of the heat source side flow switching device 40 of the heat source side second connection pipe 7, separates the flowing refrigerant into a gas refrigerant and a liquid refrigerant, and the gas refrigerant is separated into the first branching unit 10. In addition, the liquid refrigerant is supplied to the second branch portion 11. In the first heat exchanging unit 19, the primary side (the side on which the liquid refrigerant separated by the gas-liquid separator 12 flows) is the downstream side of the liquid refrigerant flow in the gas-liquid separator 12, the secondary side (in the first bypass pipe 14) The refrigerant flowing out of the second heat exchange unit 16 after passing through the third flow rate control device 15 passes through the secondary side of the second heat exchange unit 16 (the third flow rate control device 15 in the first bypass pipe 14). It is provided at a position on the downstream side of the refrigerant flow side, and performs heat exchange between the primary side refrigerant and the secondary side refrigerant.

  The second flow rate control device 13 is provided on the downstream side of the primary side of the first heat exchanging unit 19 and has a function as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. The second flow rate control device 13 may be configured by a device whose opening degree can be variably controlled, for example, a precise flow rate control means using an electronic expansion valve, an inexpensive refrigerant flow rate control means such as a capillary tube, or the like. The second heat exchange unit 16 is provided at a position where the primary side is the downstream side of the second flow rate control device 13 and the secondary side is the downstream side of the third flow rate control device 15, and the primary side refrigerant and the secondary side Heat exchange is performed with the refrigerant.

  The third flow rate control device 15 is provided on the upstream side of the secondary side of the second heat exchange unit 16 in the first bypass pipe 14, has a function as a pressure reducing valve or an expansion valve, and depressurizes the refrigerant. Inflate. Similar to the second flow control device 13, the third flow control device 15 can control the opening degree variably, for example, a precise flow control means using an electronic expansion valve, or an inexpensive refrigerant flow control such as a capillary tube. It may be configured by means or the like.

  The first branching unit 10 is provided with a number of switching devices (three in FIG. 1) corresponding to the number of connected load-side units, and controls the flow of refrigerant into and out of the load-side units via the switching device. ing. This switching device is constituted by a three-way switching valve, one of the three sides is in the gas-liquid separator 12, one of the three sides is in the heat source side first connection pipe 6, and one of the three sides is in the load side. Each unit is connected. That is, the first branching section 10 has a number of pipes through which the gas refrigerant flowing out from the gas-liquid separator 12 is conducted and the number of heat source side first connecting pipes 6 corresponding to the number of connected load side units (three in FIG. 1). The flow of the refrigerant is controlled through each of the switching devices.

  Of the connection ports of the switching device 8b, the connection port with the gas-liquid separator 12 is the connection port 8b_a, the connection port with the heat source side second connection pipe 6 is the switching device 8b_b, and the connection port with the load side unit is switched. Illustrated as device 8b_c. Similarly, of the connection ports of the switching device 8c, the connection port with the gas-liquid separator 12 is the connection port 8c_a, the connection port with the heat source side first connection pipe 6 is the switching device 8c_b, and the connection port with the load side unit. It is illustrated as a switching device 8c_c. Similarly, of the connection ports of the switching device 8d, the connection port to the gas-liquid separation device 12 is the connection port 8d_a, the connection port to the heat source side second connection pipe 6 is the switching device 8d_b, and the connection port to the load side unit is the connection port. It is illustrated as a switching device 8d_c.

  The number of the second branch parts 11 is the number of fifth check valves (fifth check valve 50b, fifth check valve 50c, fifth check valve) corresponding to the number of connected load side units (three in FIG. 1). 50d) and a sixth check valve (sixth check valve 52b, sixth check valve 52c, sixth check valve 52d) are provided to allow the refrigerant to flow to either one. The fifth check valve is connected to the primary side downstream of the second heat exchanging part 16 branched into the number (three in FIG. 1) corresponding to the number of connected load side units, and is connected to the load side unit. It is connected to the load side unit via piping (load side second connection piping 7b, load side second connection piping 7c, load side second connection piping 7d). The sixth check valve is provided in the second bypass pipe 51 branched from the pipe connected to the load side unit.

The compressor 1 is not particularly limited as long as it can compress the sucked refrigerant into a high pressure state. For example, the compressor 1 can be configured using various types such as reciprocating, rotary, scroll, or screw. The type of refrigerant used in the air conditioner 100 is not particularly limited. For example, natural refrigerants such as carbon dioxide (CO ₂ ), hydrocarbons, and helium, and alternative refrigerants that do not contain chlorine, such as HFC410A, HFC407C, and HFC404A. Alternatively, any of CFC-based refrigerants such as R22 and R134a used in existing products may be used.

  In addition, the relay E is provided with a second pressure sensor 25 and a third pressure sensor 26 that detect the pressure of the refrigerant before and after the second flow rate control device 13. The pressure information detected by these various detection means is sent to and used by a control means (not shown) that controls the operation of the air conditioner 100. This control means may be provided in the heat source machine A or in the relay machine E. Further, it may be provided on both sides so that communication is possible.

The operation at the time of heating operation of the air conditioner 100 (at the time of heating operation in the case where the heating operation is executed in all the load side units) will be described.
The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows through the heat source side heat second connection pipe 7 via the four-way valve 2 and the third check valve 34 and flows into the gas-liquid separation device 12 of the relay E. . The high-temperature and high-pressure gas refrigerant that has flowed into the gas-liquid separator 12 flows into the first branch portion 10 from above the gas-liquid separator 12.

  The gas refrigerant that has flowed into the first branch section 10 is connected to the connection port 8b_c of the switching device 8b, the connection port 8b_a of the switching device 8d, the connection port 8b_c of the switching device 8d, and the connection port 8b_c of the switching device 8d. Port 8c_c and flow to the connection port 8d_c of the switching device 8d, and load side unit B, load side unit C, load via the load side first connection pipe 6b, the load side first connection pipe 6c, and the load side first connection pipe 6d Flows into the side unit D. The gas refrigerant that has flowed into the load side unit B, the load side unit C, and the load side unit D flows into the load side heat exchanger 5 and dissipates heat to the surroundings in the load side heat exchanger 5 to heat it. It becomes a liquid refrigerant.

  This liquid refrigerant flows out of the load-side heat exchanger 5 and is slightly throttled by the first flow rate control device 9 to become an intermediate-pressure liquid refrigerant. The load-side second connection pipe 7b, the load-side second connection pipe 7c, the load It flows into the second branch portion 11 of the relay machine E through the second side connection pipe 7d. The liquid refrigerant flowing into the second branch portion 11 flows through the second bypass pipe 51 via the sixth check valve 52b, the sixth check valve 52c, and the sixth check valve 52d, and the second heat exchange portion 16 To the upstream of the primary side. The intermediate-pressure liquid refrigerant becomes a low-pressure gas-liquid two-phase refrigerant in the third flow rate control device 15 and merges with the heat source side first connection pipe 6.

  The low-pressure gas-liquid two-phase refrigerant that merged with the heat source side first connection pipe 6 flows into the heat source unit A and flows into the heat source side heat exchange unit 3 via the fourth check valve 35. The low-pressure gas-liquid two-phase refrigerant that has flowed into the heat source side heat exchanging unit 3 is divided into the first heat source side heat exchanger 41 and the second heat source side heat exchanger 42 and evaporated by the air supplied by the heat source side blower 20. -After being vaporized, it flows out from the heat source side heat exchange section 3. The refrigerant that has flowed out of the heat source side heat exchanging unit 3 is then sucked into the compressor 1 again via the four-way valve 2 and the accumulator 4. In the heat source side heat exchanging unit 3, the refrigerant may be allowed to flow into only one of the heat source side heat exchangers.

Next, the operation | movement operation | movement of the air conditioning apparatus 100 in the case of performing a defrost operation is demonstrated.
If the amount of frost formation on the first heat source side heat exchanger 41 increases while the heating operation is continued, the low pressure decreases and the temperature of the refrigerant flowing through the first heat source side heat exchanger 41 decreases. Therefore, in the air conditioning apparatus 100, when the pressure or temperature becomes a predetermined value or less, the defrosting operation is started. At this time, the four-way valve 2 is switched from the heating operation position to the cooling operation position, and the heat source side blower 20 is stopped. When the four-way valve 2 is switched, a switching sound is generated. Therefore, the frequency of the compressor 1 is temporarily reduced, and the four-way valve 2 is switched in a state where the pressure difference between the high pressure and the low pressure is small, and then the compression is performed again. The frequency of the machine 1 may be the defrosting frequency.

  In this state, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is caused to flow into the first heat source side heat exchanger 41. Then, the high-temperature and high-pressure gas refrigerant melts frost by dissipating heat in the first heat source side heat exchanger 41, and becomes a liquid refrigerant and flows out of the first heat source side heat exchanger 41. The liquid refrigerant that has flowed out of the first heat source side heat exchanger 41 flows to the heat source side second connection pipe 7 via the first check valve 32 and flows out of the heat source unit A. Then, the liquid refrigerant that has flowed through the heat source side second connection pipe 7 flows into the gas-liquid separator 12 of the relay E.

  It is assumed that only the load side unit B out of the three load side units exceeds the set temperature and is in a thermo-off state. In this case, the liquid refrigerant that has flowed into the gas-liquid separator 12 is allowed to flow from the connection port 8b_a of the switching device 8b to the connection port 8b_c. Thereby, a refrigerant flows through load side 1st connecting piping 6b, and flows in into load side unit B only. At this time, the load-side first connection pipe 6b and the load-side unit B are in a heating state because they are in a heating operation, and the liquid refrigerant is a pipe of the load-side first connection pipe 6b and the load-side heat exchanger 5. Some or all of the gas is vaporized by the heat capacity.

  This refrigerant flows through the first flow rate control device 9, the load side second connection pipe 7 b, the third flow rate control device 15, and the heat source side first connection pipe 6 and returns to the heat source machine A. The refrigerant that has returned to the heat source machine A is again sucked into the compressor 1 via the second check valve 33, the four-way valve 2, and the accumulator 4. When this state is continued and the defrosting operation is completed, the high pressure rises or the outlet temperature of the first heat source side heat exchanger 41 rises, so that the high pressure or temperature exceeds a predetermined value is detected. When it did, defrost operation is complete | finished and it returns to heating operation.

  When there is no load-side unit that is thermo-off at the start of defrosting, no refrigerant flows through the load-side unit, and all of the liquid refrigerant that has flowed into the gas-liquid separation device 12 as before is sent to the second flow rate control device 13 and The defrosting operation is performed by flowing the heat source side first connection pipe 6 through the third flow rate control device 15. In addition, although the case where the first heat source side heat exchanger 41 was frosted was described as an example, the defrosting operation is similarly performed when the second heat source side heat exchanger 42 is frosted.

  FIG. 2 is a flowchart showing the flow of processing when determining the flow of the refrigerant during the defrosting operation. Based on FIG. 2, the algorithm for determining the flow of the refrigerant during the defrosting operation will be described.

  For example, the control means (not shown) starts the heating operation based on an instruction from the user (STEP 1). The control means determines whether or not a defrosting operation start condition is satisfied (STEP 2). When it is determined that the start condition for the defrosting operation is not satisfied (STEP 2; N), the control unit repeats the determination whether the start condition for the defrosting operation is satisfied every predetermined time. When it is determined that the start condition of the defrosting operation is satisfied (STEP 2; Y), the control unit determines whether or not there is a load side unit that is thermo-off (STEP 3).

  When it is determined that there is a load-side unit that is thermo-off (STEP 3; Y), the control unit sets the switching device so that the refrigerant flows only through the load-side unit that is thermo-off, and starts the defrosting operation (STEP 4). . On the other hand, when it is determined that there is no load-side unit that is thermo-off (STEP 3; N), the control means opens the second flow control device 13 and the third flow control device 15 so as to bypass the refrigerant in the relay E. The degree is set and the defrosting operation is started (STEP 5). Then, the control means determines whether or not the defrosting operation end condition is satisfied (STEP 6).

  When it is determined that the defrosting operation end condition is not satisfied (STEP 6; N), the control unit repeats the determination of the defrosting operation end condition until the defrosting operation end condition is satisfied. When it determines with satisfy | filling the completion | finish conditions of a defrost operation (STEP6; Y), a control means determines whether a heating operation is complete | finished (STEP7). And when it determines with not complete | finishing heating operation (STEP7; N), it returns to STEP2 and continues heating operation. On the other hand, when it determines with complete | finishing heating operation (STEP7; Y), a control means complete | finishes heating operation and makes a load side unit and the heat source machine A a stop state (step S8). When performing the defrosting operation, even if there is no load-side unit that is thermo-off, priority is given to the one close to a predetermined temperature, and the refrigerant is allowed to flow to one or more load-side units. Good.

  As described above, in the air conditioning apparatus 100 according to the present embodiment, the defrosting operation is performed by flowing the refrigerant only to the load side unit that has reached the set temperature on the load side unit side or close to the set temperature. The room temperature drops too much during the defrosting operation, causing discomfort to the user, lack of heat collection, lengthening the defrosting time, and liquid back to the compressor 1. High and comfortable heating operation can be realized continuously.

Here, another example of the operation of the air conditioner 100 when performing the defrosting operation will be described.
If the amount of frost formation on the first heat source side heat exchanger 41 increases while the heating operation is continued, the low pressure decreases and the temperature of the refrigerant flowing through the first heat source side heat exchanger 41 decreases. Therefore, in the air conditioning apparatus 100, when the pressure or temperature becomes a predetermined value or less, the defrosting operation is started. At this time, the four-way valve 2 is switched from the heating operation position to the cooling operation position, and the heat source side blower 20 is stopped. When the four-way valve 2 is switched, a switching sound is generated. Therefore, the frequency of the compressor 1 is temporarily reduced, and the four-way valve 2 is switched in a state where the pressure difference between the high pressure and the low pressure is small, and then the compression is performed again. The frequency of the machine 1 may be the defrosting frequency.

  In this state, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is caused to flow into the first heat source side heat exchanger 41. Then, the high-temperature and high-pressure gas refrigerant melts frost by dissipating heat in the first heat source side heat exchanger 41, and becomes a liquid refrigerant and flows out of the first heat source side heat exchanger 41. The liquid refrigerant that has flowed out of the first heat source side heat exchanger 41 flows to the heat source side second connection pipe 7 via the first check valve 32 and flows out of the heat source unit A. Then, the liquid refrigerant that has flowed through the heat source side second connection pipe 7 flows into the gas-liquid separator 12 of the relay E.

  It is assumed that only the load side unit B is in a stopped state among the three load side units. In this case, the liquid refrigerant that has flowed into the gas-liquid separator 12 is allowed to flow from the connection port 8b_a of the switching device 8b to the connection port 8b_c. Thereby, a refrigerant flows through load side 1st connecting piping 6b, and flows in into load side unit B only. At this time, the load-side first connecting pipe 6b and the load-side unit B have a temperature about the room air temperature, but the load-side unit B is stopped, and evaporate the refrigerant in the liquid state. There is a calorie. For this reason, the liquid refrigerant evaporates due to the heat capacity of the load-side first connection pipe 6b and the pipes of the load-side heat exchanger 5, and part or all of the liquid refrigerant is gasified.

  This refrigerant flows through the first flow rate control device 9, the load side second connection pipe 7 b, the third flow rate control device 15, and the heat source side first connection pipe 6 and returns to the heat source machine A. The refrigerant that has returned to the heat source machine A is again sucked into the compressor 1 via the second check valve 33, the four-way valve 2, and the accumulator 4. When this state is continued and the defrosting operation is completed, the high pressure rises or the outlet temperature of the first heat source side heat exchanger 41 rises, so that the high pressure or temperature exceeds a predetermined value is detected. When it did, defrost operation is complete | finished and it returns to heating operation.

  When there is no load-side unit stopped at the start of defrosting, no refrigerant flows through the load-side unit, and all of the liquid refrigerant that has flowed into the gas-liquid separation device 12 is passed through the second flow control device 13 and the third as usual. The defrosting operation is carried out by flowing the heat source side first connection pipe 6 through the flow rate control device 15. In addition, although the case where the first heat source side heat exchanger 41 was frosted was described as an example, the defrosting operation is similarly performed when the heat source side heat exchanger 42 is frosted.

  As described above, in the air conditioning apparatus 100 according to the present embodiment, the defrosting operation is performed by flowing the refrigerant only to the stopped load side unit, so that the user is uncomfortable or heat collection is insufficient. Thus, a reliable and comfortable heating operation can be continuously realized without increasing the defrosting time or liquid back to the compressor 1. In other words, it is highly possible that the room where the stopped load-side unit is installed is not in use, and it is uncomfortable even if a noise is generated indoors when the refrigerant flows through the load-side unit and defrosts. There are no people to feel, sound problems are unlikely to occur, and heat extraction from the load side unit that is stopped can complete the defrosting operation in a short time, and comfortable heating can be continuously realized. .

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Heat source side heat exchange part, 4 Accumulator, 5 Load side heat exchanger, 6 Heat source side 1st connection piping, 6b Load side 1st connection piping, 6c Load side 1st connection piping, 6d Load side first connection piping, 7 Heat source side second connection piping, 7b Load side second connection piping, 7c Load side second connection piping, 7d Load side second connection piping, 8b Switching device, 8b_a connection port, 8b_b connection Port, 8b_c connection port, 8c switching device, 8c_a connection port, 8c_b connection port, 8c_c connection port, 8d switching device, 8d_a connection port, 8d_b connection port, 8d_c connection port, 9 first flow control device, 10 first branching unit , 11 2nd branch part, 12 Gas-liquid separator, 13 2nd flow control device, 14 1st bypass piping, 15 3rd flow control device, 16 2nd heat exchange part, 18 1st pressure sensor -, 19 1st heat exchange part, 20 Heat source side air blower, 25 2nd pressure sensor, 26 3rd pressure sensor, 32 1st check valve, 33 2nd check valve, 34 3rd check valve, 35 4th Check valve, 40 heat source side flow switching device, 41 first heat source side heat exchanger, 42 second heat source side heat exchanger, 43 heat source side bypass piping, 44 first electromagnetic on-off valve, 45 second electromagnetic on-off valve, 46 3rd electromagnetic on-off valve, 47 4th electromagnetic on-off valve, 48 5th electromagnetic on-off valve, 50b 5th check valve, 50c 5th check valve, 50d 5th check valve, 51 2nd bypass piping, 52b 2nd 6 check valve, 52c 6th check valve, 52d 6th check valve, 60 piping, 70 piping, 100 air conditioner, A heat source machine, B load side unit, C load side unit, D load side unit, E Relay machine.

Claims (4)

At least one heat source unit equipped with at least a compressor and a heat source side heat exchanger;
At least two load-side units on which at least the expansion device and the load-side heat exchanger are mounted;
At least one relay that is interposed between the heat source unit and the load side unit and switches the refrigerant flow path to supply the heat or cold generated by the heat source unit to the load side heat exchanger; Have
During the heating operation, when the refrigerant discharged from the compressor is caused to flow through the heat source side heat exchanger and the defrosting operation is performed to melt the frost adhering to the heat source side heat exchanger,
The air conditioner characterized in that the refrigerant that has passed through the heat source side heat exchanger flows to a load side unit that is thermo-off or stopped among the plurality of load side units. When there is no load-side unit that is thermo-off or stopped among the plurality of load-side units,
The air conditioner according to claim 1, wherein the refrigerant that has passed through the heat source side heat exchanger is returned to the compressor via the relay unit without being sent to the load side unit. . The air conditioner according to claim 1 or 2, wherein a switching device corresponding to the number of the load-side units is provided in the relay machine to switch the refrigerant flow path. The air conditioner according to claim 3, wherein the switching device is configured by a three-way switching valve.

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