JP2018013307A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner capable of reducing discomfort that a user has even if a refrigerant filling amount decreases after replacement with a combustible refrigerant.SOLUTION: A CPU 210 is configured to place, when a total requested capability as the total of requested capabilities of indoor units 5a-5t exceeds a threshold requested capability, indoor units as many as indoor units complying with the threshold requested capability in operation, and stops the remaining indoor units. Then stopped indoor unit rotation control to periodically change indoor units to be stopped is performed. Specifically, the CPU 210 is configured to stop, when the total requested capability exceeds the threshold requested capability, the indoor units 5q-5t in a group E for a predetermined time. After the predetermined time passes, the CPU 210 starts the indoor units 5q-5t in the group E and also stops the indoor units 5m-5p in a group D for the predetermined time. The indoor units in groups are stopped thereafter each for the predetermined time in the order of a group C, a group B, and a group A, and after the indoor units 5a-5d in the group A are stopped for the predetermined time, the indoor units 5q-5t in the group E are stopped again for the predetermined time.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an air conditioner having a refrigerant circuit in which an outdoor unit and a plurality of indoor units are connected by refrigerant piping.

  An air conditioner such as a multi air conditioning system for buildings has a refrigerant circuit in which an outdoor unit and a plurality of indoor units are connected by a refrigerant pipe, and circulates the refrigerant in the refrigerant circuit to use heat dissipation or heat absorption of the refrigerant. Heating or cooling the air-conditioned space is performed by overheating or cooling. In such an air conditioner, as the number of indoor units connected to the outdoor unit increases, and as the length of the refrigerant pipe connecting the outdoor unit to each indoor unit increases, the amount of refrigerant charged in the refrigerant circuit increases. Become more.

  In recent years, from the viewpoint of preventing global warming, the use of HFC refrigerants with a high global warming potential (GWP) (for example, R410A, R404A, R407C, etc.) has been restricted, and instead, refrigerants with a low GWP (for example, HFO1234yf). , R32, a mixed refrigerant containing HFO1234yf and R32, etc.) has been proposed. However, many of these refrigerants with low GWP are flammable or slightly flammable, and low-WPP and flammable or slightly flammable refrigerants are used in air conditioners such as multi air conditioning systems for buildings with a large amount of refrigerant filling. In such a case, it is necessary to take measures when the refrigerant leaks into the air-conditioned space. In the following description, a flammable or slightly flammable refrigerant with the above-described GWP may be referred to as a “flammable refrigerant”, and an HFC-based refrigerant with a high GWP may be referred to as a “non-flammable refrigerant”. is there.

  The air conditioner described in Patent Document 1 is an outdoor unit, a plurality of indoor units, a refrigerant connected to the outdoor unit and a plurality of main pipes and connected to each indoor unit by a plurality of branch pipes and flowing through the main pipe. It has a branching unit that splits each branch pipe and joins the refrigerant flowing through each branch pipe to the main pipe, and uses a combustible refrigerant as the refrigerant. This air conditioner includes a refrigerant concentration detection device and a blocking device that blocks the flow of refrigerant in the main pipe and / or each branch pipe, and determines that a refrigerant leak has occurred based on the detection value of the refrigerant concentration detection device. Then, the flow of the refrigerant in the main pipe and / or each branch pipe is blocked by the blocking device. As a result, even if refrigerant leakage occurs, the amount of leakage is minimized so that the refrigerant concentration in the air-conditioned space does not reach the concentration that causes ignition (hereinafter referred to as the ignition lower limit concentration).

International Publication No. 2012/160598

  By the way, the allowable value of the refrigerant filling amount in the refrigerant circuit of the above-described combustible refrigerant is IEC 60335-2-40 (safety standard for household electric heat pump, air conditioner, dehumidifier) or ISO 5149 (for refrigeration system and heat pump). Environmental and safety requirements). This allowable value is a value at which the refrigerant concentration in the air-conditioned space does not reach the ignition lower limit concentration even when all the refrigerant charged in the refrigerant circuit leaks into the air-conditioned space.

  On the other hand, the allowable value of the refrigerant filling amount in the refrigerant circuit of the non-combustible refrigerant that has been conventionally used is that the above ISO 5149 does not cause oxygen deficiency in the air-conditioned space even when all the refrigerant charged in the refrigerant circuit leaks into the air-conditioned space. This tolerance is greater than the tolerance for flammable refrigerants. In other words, the permissible value of the refrigerant charge amount in the same refrigerant circuit is smaller for the combustible refrigerant than for the nonflammable refrigerant.

  When replacing the refrigerant used in the air conditioner from a nonflammable refrigerant to a flammable refrigerant, replace the outdoor unit and each indoor unit with equipment compatible with the flammable refrigerant, so-called replacement that uses existing refrigerant piping There is a way to do it. In this case, the refrigerant filling amount of the flammable refrigerant is reduced as compared with the case where the nonflammable refrigerant is used. Therefore, after replacing with flammable refrigerant, the air conditioning capacity (hereinafter referred to as required capacity) required from each indoor unit that was able to be exhibited when using nonflammable refrigerant is due to insufficient refrigerant circulation. May not be able to be demonstrated. For example, when a non-flammable refrigerant was used, the maximum capacity was required for all indoor units. Only about 70% of the ability can be demonstrated.

  When the required capacity cannot be achieved with each indoor unit as described above, reduce the number of indoor units to be operated according to the current refrigerant circulation amount, that is, stop some indoor units to operate It is conceivable that the required capacity is exhibited in the indoor unit. However, if a specific indoor unit is always stopped when stopping some indoor units, the air-conditioning environment of the air-conditioned space that the stopped indoor unit is responsible for deteriorates (the temperature difference between the temperature of the air-conditioned space and the set temperature is Therefore, there is a risk of discomfort for the user existing in the air-conditioned space.

  The present invention solves the above-described problems, and an air conditioner that can reduce user discomfort even if the refrigerant charging amount is reduced by replacing the flammable refrigerant with replacement. The purpose is to provide.

  In order to solve the above-described problems, an air conditioner of the present invention has a refrigerant circuit in which an outdoor unit and a plurality of indoor units are connected by a refrigerant pipe, and the refrigerant circulates through the refrigerant circuit so that each indoor unit is The cooling operation or heating operation of the installed air-conditioned space is performed, and the refrigerant filling amount of the refrigerant circuit is smaller than the maximum filling amount that is the refrigerant filling amount that can exert the maximum capacity of each indoor unit in all indoor units. Regulated filling amount. The total required capacity, which is the sum of the required capacities of all indoor units, exceeds the threshold required capacity, which is the sum of the maximum capacities that can be exhibited by each indoor unit when the regulated charge amount of refrigerant is filled. Control to execute stop indoor unit rotation control that stops the number of indoor units corresponding to the difference between the sum of the maximum capacity of each indoor unit and the threshold required capacity, and changes the stopped indoor unit every predetermined time Have means.

  According to the air conditioner of the present invention configured as described above, when the required capacity cannot be exhibited in all indoor units by reducing the refrigerant charging amount by replacing the flammable refrigerant with replacement, Since the stop indoor unit is changed every predetermined time, user discomfort can be reduced.

It is explanatory drawing of the air conditioning apparatus in 1st Embodiment of this invention, (A) is a refrigerant circuit figure, (B) is a block diagram of an outdoor unit control means and an indoor unit control means. It is drawing showing the installation state of the indoor unit and outdoor unit in 1st Embodiment of this invention. It is a stop indoor unit selection table in 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, in order to replace the refrigerant to be used from a non-flammable refrigerant to a flammable refrigerant, an outdoor unit and a plurality of indoor units corresponding to a flammable refrigerant from an outdoor unit and a plurality of indoor units corresponding to the non-flammable refrigerant are used. The refrigerant pipe that connects the outdoor unit and the plurality of indoor units will be described as an example of an air conditioner that uses an existing refrigerant pipe. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention.

  As shown in FIG. 1 (A) and FIG. 2, the air conditioner 1 in the present embodiment is installed in a room 300, which is an air-conditioned space, and an outdoor unit 2 installed in the room 300. The unit 2 is provided with 20 indoor units 5a to 5t having the same ability to be connected in parallel with the existing liquid pipe 8 and gas pipe 9 by electric wiring 10. Specifically, one end of the liquid pipe 8 is connected to the closing valve 25 of the outdoor unit 2, and the other end of the liquid pipe 8 is branched and connected to the liquid pipe connection portions 53a to 53t of the indoor units 5a to 5t. Yes. One end of the gas pipe 9 is connected to the closing valve 26 of the outdoor unit 2, and the other end of the gas pipe 9 is branched and connected to the gas pipe connection portions 54a to 54t of the indoor units 5a to 5t. As described above, the outdoor unit 2 and the ten indoor units 5a to 5t are connected to each other to configure the refrigerant circuit 100 of the air conditioner 1. One end of the electrical wiring 10 is connected to the communication unit 230 of the outdoor unit 2 described later, and the other end of the electrical wiring 10 is branched and connected to the communication units 530a to 530t of the indoor units 5a to 5t described later. .

  FIG. 1A shows only the indoor unit 5a, the indoor unit 5b, and the indoor unit 5t among the 20 indoor units 5a to 5t. The refrigerant circuit 100 uses a flammable refrigerant having a low GWP, such as HFO1234yf, R32, or a mixed refrigerant containing these. The outdoor unit 2 and the 20 indoor units 5a to 5t described below are each designed to correspond to a combustible refrigerant. In other words, the air conditioner 1 originally has an outdoor unit (hereinafter referred to as an old outdoor unit) corresponding to a non-combustible refrigerant such as R410A and 20 indoor units (hereinafter referred to as an old indoor unit). From what was comprised by connecting with the gas pipe 9, it replaced with the outdoor unit 2 and 20 indoor units 5a-5t corresponding to a combustible refrigerant | coolant, and each capability is the same as an old outdoor unit and an old indoor unit, The refrigerant circuit 100 in which the liquid pipe 8 and the gas pipe 9 are diverted to connect the outdoor unit 2 and the 20 indoor units 5a to 5t is filled with a combustible refrigerant.

  First, the outdoor unit 2 will be described. The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor expansion valve 24, a closing valve 25 to which one end of the liquid pipe 8 is connected, and one end of the gas pipe 9. A closing valve 26, an accumulator 28, and an outdoor fan 27 are provided. These devices other than the outdoor fan 27 are connected to each other through refrigerant pipes described in detail below to constitute an outdoor unit refrigerant circuit 20 that forms part of the refrigerant circuit 100.

  The compressor 21 is a variable capacity compressor that can vary its operating capacity by being driven by a motor (not shown) whose rotation speed is controlled by an inverter. The refrigerant discharge side of the compressor 21 is connected to a port a of a four-way valve 22 described later by a discharge pipe 41, and the refrigerant suction side of the compressor 21 is connected to the refrigerant outflow side of the accumulator 28 by a suction pipe 42. Has been.

  The four-way valve 22 is a valve for switching the direction in which the refrigerant flows, and includes four ports a, b, c, and d. The port a is connected to the refrigerant discharge side of the compressor 21 by the discharge pipe 41 as described above. The port b is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 23 by a refrigerant pipe 43. The port c is connected to the refrigerant inflow side of the accumulator 28 by a refrigerant pipe 46. The port d is connected to the closing valve 26 by an outdoor unit gas pipe 45.

  The outdoor heat exchanger 23 exchanges heat between the refrigerant and outside air taken into the outdoor unit 2 by rotation of an outdoor fan 27 described later. As described above, one refrigerant inlet / outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 by the refrigerant pipe 43, and the other refrigerant inlet / outlet is connected to the closing valve 25 by the outdoor unit liquid pipe 44.

  The outdoor expansion valve 24 is provided in the outdoor unit liquid pipe 44. The outdoor expansion valve 24 is an electronic expansion valve. When the air-conditioning apparatus 1 performs a heating operation, that is, when the outdoor heat exchanger 23 functions as an evaporator, the compressor 21 detected by a discharge temperature sensor 33 described later. The opening degree is adjusted in accordance with the discharge temperature, so that the discharge temperature does not exceed the performance upper limit value. Further, when the air conditioner 1 is performing a cooling operation, that is, when the outdoor heat exchanger 23 functions as a condenser, the opening degree is fully opened.

  The outdoor fan 27 is formed of a resin material and is disposed in the vicinity of the outdoor heat exchanger 23. The outdoor fan 27 is rotated by a fan motor (not shown) to take outside air from a suction port (not shown) into the outdoor unit 2, and the outdoor air heat exchanged with the refrigerant in the outdoor heat exchanger 23 is sent from the blower outlet (not shown) to the outdoor unit 2. To the outside.

  As described above, the accumulator 28 has the refrigerant inflow side connected to the port c of the four-way valve 22 via the refrigerant pipe 46 and the refrigerant outflow side connected to the refrigerant intake side of the compressor 21 via the suction pipe 42. The accumulator 28 separates the refrigerant flowing into the accumulator 28 from the refrigerant pipe 46 into a gas refrigerant and a liquid refrigerant, and causes the compressor 21 to suck only the gas refrigerant.

  In addition to the configuration described above, the outdoor unit 2 is provided with various sensors. As shown in FIG. 1A, the discharge pipe 41 includes a discharge pressure sensor 31 that detects the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature that detects the temperature of the refrigerant discharged from the compressor 21. A sensor 33 is provided. Near the refrigerant inlet of the accumulator 28 in the refrigerant pipe 46, a suction pressure sensor 32 that detects the pressure of the refrigerant sucked into the compressor 21 and a suction temperature sensor 34 that detects the temperature of the refrigerant sucked into the compressor 21. Is provided.

  Between the outdoor heat exchanger 23 and the outdoor expansion valve 24 in the outdoor unit liquid pipe 44, the temperature of the refrigerant flowing into the outdoor heat exchanger 23 or the temperature of the refrigerant flowing out of the outdoor heat exchanger 23 is detected. A heat exchanger temperature sensor 35 is provided. An outdoor air temperature sensor 36 that detects the temperature of the outside air that flows into the outdoor unit 2, that is, the outside air temperature, is provided near the suction port (not shown) of the outdoor unit 2.

  The outdoor unit 2 includes an outdoor unit control means 200. The outdoor unit control means 200 is mounted on a control board stored in an electrical component box (not shown) of the outdoor unit 2. As shown in FIG. 1B, the outdoor unit control means 200 includes a CPU 210, a storage unit 220, a communication unit 230, and a sensor input unit 240.

  The storage unit 220 includes a ROM and a RAM, and stores a control program for the outdoor unit 2, detection values corresponding to detection signals from various sensors, control states of the compressor 21 and the outdoor fan 27, and the like. The communication unit 230 is an interface that performs communication with the indoor units 5a to 5c. The sensor input unit 240 captures detection results from various sensors of the outdoor unit 2 and outputs them to the CPU 210.

  CPU210 takes in the detection result in each sensor of outdoor unit 2 mentioned above via sensor input part 240. FIG. Further, the CPU 210 takes in a control signal, which will be described later, transmitted from the indoor units 5 a to 5 t via the communication unit 230 and the electrical wiring 10. The CPU 210 performs drive control of the compressor 21 and the outdoor fan 27 based on the detection results and control signals taken in. In addition, the CPU 210 performs switching control of the four-way valve 22 based on the detection results and control signals taken in. Furthermore, the CPU 210 adjusts the opening degree of the outdoor expansion valve 24 based on the acquired detection result and control signal.

  Next, 20 indoor units 5a to 5t will be described. Twenty indoor units 5a to 5t branch to indoor heat exchangers 51a to 51t, indoor expansion valves 52a to 52t, and liquid pipe connection portions 53a to 53t to which the other ends of the branched liquid pipes 8 are connected. Gas pipe connection parts 54a to 54t to which the other ends of the gas distribution pipes 9a to 9c are connected and indoor fans 55a to 55t are provided. And these apparatuses except indoor fan 55a-55t are mutually connected by each refrigerant | coolant piping explained in full detail below, and comprise the indoor unit refrigerant circuit 50a-50t which makes a part of refrigerant circuit 100. FIG.

  Below, the structure of the 20 indoor units 5a-5t is demonstrated in detail. Since all the indoor units 5a to 5t have the same configuration, the following description will be made in detail by taking the indoor unit 5a as an example, and detailed descriptions of the other indoor units 5b to 5t will be omitted. Moreover, in FIG. 1, what changed the end of the number provided to the component apparatus of the indoor unit 5a from a to b-t becomes the component apparatus of the indoor units 5b-5t corresponding to the component apparatus of the outdoor unit 5a. .

The indoor heat exchanger 51a exchanges heat between the refrigerant and room air taken into the indoor unit 5a from a suction port (not shown) by rotation of an indoor fan 55a described later, and one refrigerant inlet / outlet is connected to a liquid pipe. The indoor unit liquid pipe 71a is connected to the section 53a, and the other refrigerant inlet / outlet is connected to the gas pipe connecting section 54a through the indoor unit gas pipe 72a. The indoor heat exchanger 51a functions as an evaporator when the indoor unit 5a performs a cooling operation, and functions as a condenser when the indoor unit 5a performs a heating operation.
Note that the refrigerant pipes of the liquid pipe connecting part 53a and the gas pipe connecting part 54a are connected by welding, flare nuts, or the like.

  The indoor expansion valve 52a is provided in the indoor unit liquid pipe 71a. The indoor expansion valve 52a is an electronic expansion valve, and when the indoor heat exchanger 51a functions as an evaporator, that is, when the indoor unit 5a performs a cooling operation, the opening degree of the indoor expansion valve 52a depends on the refrigerant outlet (gas gas) of the indoor heat exchanger 51a. The refrigerant superheat degree at the pipe connecting portion 54a side) is adjusted to be the target refrigerant superheat degree. Further, when the indoor heat exchanger 51a functions as a condenser, that is, when the indoor unit 5a performs a heating operation, the opening of the indoor expansion valve 52a is the refrigerant outlet (liquid pipe connection portion) of the indoor heat exchanger 51a. 53a side) is adjusted so that the refrigerant subcooling degree becomes the target refrigerant subcooling degree. Here, the target refrigerant superheat degree and the target refrigerant subcool degree are the refrigerant superheat degree and the refrigerant subcool degree necessary for exhibiting sufficient cooling capacity or heating capacity in the indoor unit 5a.

  The indoor fan 55a is formed of a resin material and is disposed in the vicinity of the indoor heat exchanger 51a. The indoor fan 55a is rotated by a fan motor (not shown) to take indoor air from the suction port (not shown) into the indoor unit 5a, and the indoor air exchanged with the refrigerant in the indoor heat exchanger 51a from the blower outlet (not shown). Release into the room.

  In addition to the configuration described above, the indoor unit 5a is provided with various sensors. Between the indoor heat exchanger 51a and the indoor expansion valve 52a in the indoor unit liquid pipe 71a, a liquid side temperature sensor 61a that detects the temperature of the refrigerant flowing into or out of the indoor heat exchanger 51a. Is provided. The indoor unit gas pipe 72a is provided with a gas side temperature sensor 62a that detects the temperature of the refrigerant flowing out of the indoor heat exchanger 51a or flowing into the indoor heat exchanger 51a. A suction temperature sensor 63a for detecting the temperature of the indoor air flowing into the indoor unit 5a, that is, the suction temperature, is provided near the suction port (not shown) of the indoor unit 5a.

  The indoor unit 5a includes an indoor unit control means 500a. The indoor unit control means 500a is mounted on a control board stored in an electrical component box (not shown) of the indoor unit 5a. As shown in FIG. 1B, a CPU 510a, a storage unit 520a, a communication unit 530a, The sensor input unit 540a is provided.

  The storage unit 520a includes a ROM and a RAM, and stores a control program for the indoor unit 5a, detection values corresponding to detection signals from various sensors, setting information regarding air conditioning operation by the user, and the like. The communication unit 530a is an interface that communicates with the outdoor unit 2 and the other indoor units 5b and 5c. The sensor input unit 540a captures detection results from various sensors of the indoor unit 5a and outputs them to the CPU 510a.

  The CPU 510a takes in the detection result of each sensor of the indoor unit 5a described above via the sensor input unit 540a. Further, the CPU 510a takes in a signal including operation information set by operating a remote controller (not shown), a timer operation setting, and the like via a remote control light receiving unit (not shown). Further, the CPU 510a transmits a control signal including an operation start / stop signal and operation information (required capacity, set temperature, indoor temperature, etc.) to the outdoor unit 2 via the communication unit 530a and the electric wiring 10, and the outdoor unit A control signal including information such as discharge pressure detected by the machine 2 is received from the outdoor unit 2 via the communication unit 530 a and the electrical wiring 10. The CPU 510a performs the opening degree adjustment of the indoor expansion valve 52a and the drive control of the indoor fan 55a based on the acquired detection result and the signal transmitted from the remote controller and the outdoor unit 2.

  The outdoor unit control unit 200 and the indoor unit control units 500a to 500t described above constitute the control unit of the present invention.

  The air conditioning apparatus 1 described above is installed in a room 300 shown in FIG. The outdoor unit 2 is arranged outdoors in the room 300, and 20 indoor units 5 a to 5 t are installed in the room 300. One wall surface of the room 300 is provided with a window 310 arranged in the left-right direction. Moreover, the entrance / exit 320 is provided in a part of wall surface facing the wall surface in which the window 310 of the room 300 is provided. Twenty indoor units 5a to 5t are arranged side by side at approximately equal intervals in the left-right direction of the room 300, and five are arranged at substantially equal intervals in the direction from the window 310 toward the entrance / exit 320. That is, in the room 300, the indoor units 5a to 5t are arranged such that five rows of four indoor units arranged in the left-right direction are arranged in the direction from the window 310 to the entrance / exit 320.

  More specifically, in the row closest to the window 310, four indoor units 5a to 5d are arranged. The row composed of the indoor units 5a to 5d is hereinafter referred to as A group. In the next row of the A group, that is, the row on the entrance / exit 320 side of the A group, four indoor units 5e to 5h are arranged. Hereinafter, the row composed of the indoor units 5e to 5h is referred to as a B group. Hereinafter, in order toward the entrance / exit 320, a row in which four indoor units of indoor units 5i to 5l are arranged, a row in which four indoor units of indoor units 5m to 5p are arranged, and four units of indoor units 5q to 5t. There are columns in which the indoor units are arranged, and each column is sequentially referred to as a C group, a D group, and an E group.

  Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 100 during the air conditioning operation of the air-conditioning apparatus 1 in the present embodiment will be described with reference to FIG. In the following description, the case where the air conditioner 1 performs the cooling operation and the case where all the indoor units 5a to 5t are operated will be described, and the detailed description will be omitted for the case where the heating operation is performed. Moreover, the arrow in FIG. 1 (A) has shown the flow of the refrigerant | coolant at the time of air_conditionaing | cooling operation.

  As shown in FIG. 1, when the air conditioning apparatus 1 performs a cooling operation, the CPU 210 of the outdoor unit control means 200 is in a state where the four-way valve 22 is indicated by a solid line, that is, the port a and the port b of the four-way valve 22 communicate with each other. In addition, switching is performed so that the port c and the port d communicate with each other. Thereby, the refrigerant circuit 100 becomes a cooling cycle in which the outdoor heat exchanger 23 functions as a condenser and the indoor heat exchangers 51a to 51t function as evaporators.

  The high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 41 and flows into the four-way valve 22, flows from the four-way valve 22 through the refrigerant pipe 43, and flows into the outdoor heat exchanger 23. The refrigerant flowing into the outdoor heat exchanger 23 is condensed by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27. The refrigerant that has flowed out of the outdoor heat exchanger 23 into the outdoor unit liquid pipe 44 is decompressed by the outdoor expansion valve 24, and flows out to the liquid pipe 8 through the closing valve 25.

  The refrigerant flowing through the liquid pipe 8 flows into the indoor units 5a to 5t via the liquid pipe connection portions 53a to 53t. The refrigerant flowing into the indoor units 5a to 5t flows through the indoor unit liquid pipes 71a to 71t, passes through the indoor expansion valves 52a to 52t, and is decompressed. The decompressed refrigerant flows into the indoor heat exchangers 51a to 51t, and evaporates by exchanging heat with the indoor air taken into the indoor units 5a to 5t by the rotation of the indoor fans 55a to 55t. In this way, the indoor heat exchangers 51a to 51t function as evaporators, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchangers 51a to 51t is blown into the room from a blowout port (not shown), thereby The room where the machines 5a to 5t are installed is cooled.

  The refrigerant that has flowed out of the indoor heat exchangers 51a to 51t flows through the indoor unit gas pipes 72a to 72t, and flows out to the gas pipe 9 through the gas pipe connection portions 54a to 54t. The refrigerant flowing through the gas pipe 9 and flowing into the outdoor unit 2 through the closing valve 26 flows in the order of the outdoor unit gas pipe 45, the four-way valve 22, the refrigerant pipe 46, the accumulator 28, and the suction pipe 42, and is sucked into the compressor 21. And compressed again.

  When the air conditioner 1 performs the heating operation, the CPU 210 is in a state where the four-way valve 22 is indicated by a broken line, that is, the port a and the port d of the four-way valve 22 communicate with each other, and the port b and the port c communicate with each other. Switch to Thereby, the refrigerant circuit 100 becomes a heating cycle in which the outdoor heat exchanger 23 functions as an evaporator and the indoor heat exchangers 51a to 51t of the indoor units 5a to 5t function as condensers.

  By the way, when the air conditioning apparatus 1 performs a cooling operation or a heating operation, in each of the indoor units 5a to 5t, the CPUs 510a to 510t of the indoor unit control means 500a to 500t have a set temperature and a suction temperature sensor 63a determined by the user. The temperature difference between the indoor temperatures detected at -63t and taken in via the sensor input units 540a-540t is calculated, and the required capacity of each indoor unit 5a-5t based on this temperature difference is calculated via the communication units 530a-530t. 2 to send.

  On the other hand, the CPU 210 of the outdoor unit control means 200 that has received the required capacity of each of the indoor units 5a to 5t via the communication unit 230 calculates the total required capacity that is the sum of the required capabilities of the indoor units 5a to 5t, The number of revolutions of the compressor 21 for circulating the amount of refrigerant necessary to achieve the calculated total required capacity to the refrigerant circuit 100 is determined. Then, the CPU 210 drives and controls the compressor 21 at the determined rotational speed.

  As described above, the air conditioner 1 of the present embodiment was originally configured by connecting the old outdoor unit corresponding to the nonflammable refrigerant and the 20 old indoor units by the liquid pipe 8 and the gas pipe 9. Therefore, it replaces with the outdoor unit 2 and 20 indoor units 5a to 5t corresponding to the flammable refrigerant and has the same capacity as the old outdoor unit and the old indoor unit, and diverts the liquid pipe 8 and the gas pipe 9 to the outdoor. The refrigerant circuit 100 in which the machine 2 and the 20 indoor units 5a to 5t are connected is filled with a combustible refrigerant.

  When the old outdoor unit is replaced with the outdoor unit 2 and 20 old indoor units are replaced with the indoor units 5a to 5t and the refrigerant circuit 100 is filled with the combustible refrigerant, the old refrigerant is used for the filling amount. May be less. This is because standards such as IEC 60335-2-40 and ISO 5149 allow an acceptable filling amount (hereinafter referred to as a maximum filling amount) of the flammable refrigerant and the slightly flammable refrigerant compared to the non-flammable refrigerant. This maximum filling amount is determined as an allowable filling amount regardless of the size of the room, for example, in ISO 5149, if provision is made for management of refrigerant concentration in a room such as a ventilation fan or a gas leak sensor. The non-flammable refrigerant is 150 kg regardless of the type of refrigerant, whereas in the case of flammable refrigerant and slightly flammable refrigerant, the amount is determined according to the minimum ignition concentration of each refrigerant. Is about 60 kg.

  For this reason, when the air conditioner 1 is composed of an old outdoor unit and 20 old indoor units and uses an old refrigerant, each indoor unit is requested even if the maximum capacity of each indoor unit is required in each indoor unit. If the refrigerant charge amount that can demonstrate the maximum capacity required in step 1 is replaced with a flammable refrigerant or a slightly flammable refrigerant by replacement, it will be charged compared to the old refrigerant even if it is filled to the regulated charge amount There is a risk that the capacity will be reduced and the maximum capacity of each indoor unit cannot be demonstrated. For example, assuming that the total required capacity when the maximum capacity is required in all old indoor units is 100, the total request is lower than the total required capacity by the refrigerant charge amount of the difference between the maximum charge amount and the regulated charge amount. Only ability (hereinafter referred to as threshold requirement ability; for example, 80) can be exhibited.

  Therefore, in the air conditioner 1 in which the nonflammable refrigerant is replaced with the flammable refrigerant as described above, when the total required capacity of the indoor units 5a to 5t exceeds the threshold required capacity, the total value of the maximum capacity of each indoor unit By stopping the number of indoor units corresponding to the difference between the threshold required capacity and the threshold required capacity, it is conceivable that the indoor units that are in operation are used to the maximum capacity. For example, in the air conditioner 1 of the present embodiment, when the threshold required capacity is 80% of the total value of the maximum capacity of each indoor unit, when the maximum capacity is required for all the indoor units 5a to 5t. Any one of the 20 indoor units 5a to 5t may be stopped.

  However, as described above, when the four indoor units are stopped, if the specific four indoor units among the indoor units 5a to 5t are always stopped, the air conditioning space that the stopped indoor unit takes over, that is, the stop in the room 300 is stopped. The indoor temperature below the indoor unit rises or falls, and the temperature difference from the set temperature becomes larger than the air-conditioned space that is operated by the indoor unit that is operating. As a result, there is a risk of discomfort for the user existing in the air-conditioned space.

  Therefore, in the air conditioner 1 of the present embodiment, when the total required capacity of each indoor unit 5a to 5t exceeds the threshold required capacity, 16 units corresponding to the threshold required capacity among the indoor units 5a to 5t. The remaining four indoor units are stopped. And stop indoor unit rotation control which changes four indoor units to stop regularly is performed.

  Specifically, the CPU 210 of the outdoor unit control means 200 first sets the E group indoor units 5q to 5t for a predetermined time (when the sum of the required capacities taken from the indoor units 5a to 5t exceeds the threshold required capacity). For example, stop for 20 minutes). When the predetermined time has elapsed, the CPU 210 activates the indoor units 5q to 5t of the E group and stops the indoor units 5m to 5p of the D group for a predetermined time. Thereafter, the indoor units of each group are stopped for a predetermined time in the order of C group, B group, and A group, and after the indoor units 5a to 5d of the A group are stopped for a predetermined time, the indoor units 5q to 5t of the E group are again predetermined. To time. Note that the predetermined time is determined in advance by performing a test or the like, and even if the indoor unit is stopped during this time, the air-conditioning environment of the air-conditioned space that the indoor unit is responsible for deteriorates (for example, the set temperature and the indoor temperature). This is the time when it has been confirmed that the temperature difference of temperature does not become 6 ° C. or higher.

  Here, the reason why the columns to be stopped are in the order of E, D, C, B, and A is as follows. As shown in FIG. 2, since the indoor units 5a to 5d of the A group are installed in the vicinity of the window 310 that becomes a large air conditioning load, the indoor units 5a to 5d take charge when the indoor units 5a to 5d are stopped. The rate of increase or decrease in the indoor temperature in the air-conditioned space is faster than the air-conditioned space that is handled by the indoor units constituting other rows. The rate of increase or decrease in the indoor temperature decreases as the distance from the window 310 increases, and the increase or decrease in the indoor temperature in the air-conditioned space of the E group indoor units 5q to 5t arranged at the farthest position from the window 310. The speed of is slower than the conditioned space that the indoor units constituting the other rows are responsible for.

  When the stop indoor unit rotation control is performed during the cooling operation, if the stop is performed from the indoor units 5a to 5d of the A group affected by the window 310, the indoor temperature in the air-conditioned space that the indoor units 5a to 5d are responsible for greatly increases in a short time. Or it may fall and the air-conditioning environment of the said air-conditioned space may deteriorate and give a user a great discomfort. On the other hand, if the indoor units that are stopped from the E group and are sequentially stopped toward the A group are changed, the entire room 300 is warmed or cooled to some extent before the indoor units 5a to 5d of the A group are stopped. Therefore, when the indoor units 5a to 5d of the A group are stopped, the air-conditioning environment of the air-conditioned space is not deteriorated so much that the user's discomfort can be reduced.

  In addition, when the total required capacity of the indoor units 5a to 5t exceeds the threshold required capacity, the ability to operate all the indoor units 5a to 5t and exhibit them in each of the indoor units 5a to 5t instead of providing the stop indoor unit Can be constrained to a value obtained by dividing the threshold required capacity by the number of indoor units 5a to 5t (20 in this embodiment), that is, a capacity lower than the maximum capacity. However, if the capability exhibited by all the indoor units 5a to 5t is suppressed to a capability lower than the maximum capability in this way, there is a possibility that the user who requests the maximum capability may feel uncomfortable.

  Further, since the gas refrigerant and the liquid refrigerant exist in the indoor heat exchangers 51a to 51t of all the indoor units 5a to 5t, there are stop indoor units in which only the gas refrigerant exists in the indoor heat exchanger during the heating operation. When the cooling operation is performed, the amount of refrigerant circulating in the entire air conditioner 1 is reduced as compared with the case where there is a stopped indoor unit in the indoor heat exchanger in which the refrigerant does not substantially exist, and the total capacity exhibited by the indoor units 5a to 5t is added. There is a risk that the value will be smaller than when there is a stop indoor unit.

  For the reason described above, when the total required capacity of the indoor units 5a to 5t exceeds the threshold required capacity, the total value of the maximum capacity and the threshold required capacity of each indoor unit are operated rather than operating all the indoor units 5a to 5t. If the number of indoor units corresponding to the difference is stopped, the combined value of the capabilities exhibited by the indoor units 5a to 5t can be increased.

  As described above, the air conditioner 1 of the present embodiment stops the number of indoor units corresponding to the threshold required capacity when the total required capacity of all the indoor units 5a to 5t exceeds the threshold required capacity. At the same time, stop indoor unit rotation control is performed in which the stopped indoor units are changed every predetermined time. For this reason, even if the refrigerant | coolant with which the refrigerant | coolant circuit 100 is filled becomes a combustible refrigerant | coolant and a filling amount reduces and the total request | requirement capability which can be exhibited with the air conditioning apparatus 1 resulting from this falls, a user's discomfort is felt. Can be reduced.

  In the embodiment described above, when the stop indoor unit rotation control is performed, the stop time of the indoor units constituting each group is uniformly set to a predetermined time. However, the influence of the air conditioning load caused by the window 310 is greatly increased. The stop time of the indoor units 5a to 5d in the A group is 5 minutes, and then the stop time of the indoor units 5e to 5h in the B group close to the window 310 is 10 minutes. The stop time of the indoor units 5a to 5d of the group A that is greatly received may be shortened the shortest, and the stop time may be sequentially increased as the distance from the window 310 increases. By performing the stop indoor unit rotation control in this way, the time during which the indoor units 5a to 5d of the A group close to the window 310 are stopped can be shortened, so that the deterioration of the air conditioning environment of the air conditioning space that the indoor units 5a to 5d are responsible for is minimized. This can further reduce the user's discomfort in the air-conditioned space.

  Next, a second embodiment of the air conditioner of the present invention will be described. In the air conditioner according to the second embodiment of the present invention, the configuration of the outdoor unit 2 and the 20 indoor units 5a to 5t, the mutual connection state by the liquid pipe 8 and the gas pipe 9, and the 20 indoor units in the room 300. About arrangement | positioning of 5a-5t, since it is the same as the air conditioning apparatus 1 of 1st Embodiment demonstrated using FIG. 1 and FIG. 2, detailed description is abbreviate | omitted. The difference from the first embodiment is that in the stopped indoor unit rotation control, instead of sequentially stopping the indoor units constituting the A group to E group shown in FIG. The indoor unit to be stopped for a predetermined time is determined using the unit selection table 400.

  The stop indoor unit selection table 400 shown in FIG. 3 is stored in the storage unit 220 possessed by the outdoor unit control means 200 of the outdoor unit 2, and when the indoor units 5a to 5t are performing the cooling operation. The set temperature determined by the user, the indoor temperature detected by each of the suction temperature sensors 63a to 63t and transmitted to the outdoor unit 2, the temperature difference obtained by subtracting the set temperature from the indoor temperature, and the order based on the temperature difference Are stored for each of the indoor units 5a to 5t. The stop indoor unit selection table 400 is received by the outdoor unit 2 when the set temperature of the indoor units 5a to 5t is changed by the user or periodically (for example, every 30 seconds). Each time you do it, its contents are updated. Moreover, although illustration is abbreviate | omitted, the stop indoor unit selection table when the indoor units 5a-5t are performing the heating operation separately from what is shown in FIG.

  Here, the rank is given a high rank to those having a small temperature difference, that is, a small difference between the set temperature and the room temperature, and the rank is lowered as the temperature difference increases. When executing the stop indoor unit rotation control in the present embodiment, the CPU 210 refers to the stop indoor unit selection table 400 every predetermined time (for example, 20 minutes), and the predetermined number in order from the highest ranking. The indoor unit is selected and the indoor unit is stopped. For example, in the air conditioner 1 of the present embodiment, when the threshold required capacity is 80% of the total required capacity when the maximum capacity is required in all the indoor units 5a to 5t, all the indoor units 5a. When the maximum capacity is requested at ˜5t, the CPU 210 refers to the stop indoor unit selection table 400 every predetermined time, and the four indoor units 5a to 5t are ranked in order from the highest one. What is necessary is just to select an indoor unit and to stop the said indoor unit.

  Specifically, in the stopped indoor unit selection table 400 shown in FIG. 3, the highest rank (ranked first) is the three indoor units 5r, 5s, and 5t having a temperature difference of 0 ° C. The next highest ranking (ranking second) is the indoor unit 5p having a temperature difference of + 1 ° C. The CPU 210 refers to the stop indoor unit selection table 400 when executing the stop indoor unit rotation control when the required capacity of all the indoor units 5a to 5t exceeds the threshold required capacity during the cooling operation. A total of four indoor units 5r, 5s, and 5t with the highest ranking and the indoor unit 5p with the second highest ranking are stopped for a predetermined time. Then, after the predetermined time has passed, the stop indoor unit selection table 400 is referred again, and four indoor units having the highest priority are selected, and the indoor units are stopped.

  The predetermined time is determined by conducting a test or the like in advance as in the first embodiment, and even if the indoor unit stops during this time, the air-conditioning environment of the air-conditioned space that the indoor unit is responsible for is extremely This is the time when it has been confirmed that the temperature does not deteriorate (for example, the temperature difference between the set temperature and the room temperature is 6 ° C. or more).

  As described above, the air conditioner 1 of the present embodiment selects the indoor unit selected using the stop indoor unit selection table 400 when the required capacity of all the indoor units 5a to 5t exceeds the threshold required capacity. Stop indoor unit rotation control is performed to select the indoor unit to be stopped and stop again every predetermined time. Thereby, even if the refrigerant | coolant with which the refrigerant | coolant circuit 100 is filled becomes a combustible refrigerant | coolant, and the filling amount reduces and the air-conditioning capability which can be exhibited with the air conditioning apparatus 1 resulting from this falls, a user's discomfort is reduced. it can.

  In addition, the indoor units that are stopped when the stop indoor unit rotation control of the present embodiment is performed are selected in the stop indoor unit selection table 400, which has a higher rank, that is, the temperature difference between the room temperature and the set temperature is small. Therefore, even if the indoor temperature rises or falls while the indoor unit is stopped, the temperature difference between the set temperature and the indoor temperature becomes smaller than when the other indoor units are stopped. There is little uncomfortable feeling of the user who exists in the air-conditioned space.

  In each embodiment described above, the 20 indoor units 5a to 5t can exhibit the same maximum capacity, and the ratio of the threshold required capacity to the total value of the maximum capacity of the indoor units 5a to 5t is the total number of stop indoor units. When the threshold required capacity is 80% of the total value of the maximum capacity of the indoor units 5a to 5t, the number of indoor units to stop is also 80% of the total number (20 units). The case of using four units has been described. On the other hand, when the air conditioner is configured with a plurality of types of indoor units having different capacities, the sum of the maximum capacities of the stopped indoor units is the difference between the sum of the threshold required capacities and the maximum capacities of the indoor units 5a to 5t. As such, an indoor unit that is stopped by combining a plurality of indoor units having different maximum capacities may be determined.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 5a-5t Indoor unit 8 Liquid pipe 9 Gas pipe 10 Electrical wiring 63a-63t Suction temperature sensor 100 Refrigerant circuit 200 Outdoor unit control part 210 CPU
220 Storage Unit 230 Communication Unit 300 Room 310 Window 320 Entrance / Exit 400 Stop Indoor Unit Selection Table 500a to 500t Indoor Unit Control Unit 510a to 510t CPU
530a to 530t communication unit 540a to 540t sensor input unit

Claims (4)

An air conditioner having a refrigerant circuit in which an outdoor unit and a plurality of indoor units are connected by a refrigerant pipe, and performing a cooling operation or a heating operation of an air-conditioned space in which each indoor unit is installed by circulating the refrigerant through the refrigerant circuit A device,
The refrigerant charging amount of the refrigerant circuit is a regulated charging amount that is less than the maximum charging amount that is a refrigerant charging amount that can exhibit the maximum capacity of each indoor unit in all the indoor units,
The total required capacity, which is the sum of the required capacities of all the indoor units, is a threshold required capacity that is the sum of the maximum values of the capacities that can be exhibited by each of the indoor units when the regulated charging amount of refrigerant is filled. When it exceeds, the number of indoor units corresponding to the difference between the sum of the maximum capacity of each indoor unit and the threshold required capacity is stopped, and stop indoor unit rotation control is performed to change the stopped indoor unit every predetermined time. Having control means to perform,
An air conditioner characterized by that. The refrigerant charged in the refrigerant circuit is a flammable refrigerant or a slightly flammable refrigerant,
The air conditioning apparatus according to claim 1. The plurality of indoor units are divided into a plurality of groups based on the number of the stopped indoor units in the stopped indoor unit rotation control.
The control means sequentially stops the plurality of groups of indoor units every predetermined time when executing the stop indoor unit rotation control.
The air conditioner according to claim 1 or 2, wherein The plurality of indoor units have a suction temperature sensor for detecting a suction temperature,
The control means calculates a temperature difference obtained by subtracting a set temperature from the suction temperature every predetermined time when executing the stop indoor unit rotation control, and sequentially calculates the total required capacity and the threshold value in ascending order of the temperature difference. Select the number corresponding to the difference in required capacity and stop the selected indoor unit.
The air conditioner according to claim 1 or 2, wherein

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