JP2017110856A - Air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning device free from leakage of condensate water after stop of a cooling operation in a floor-installed indoor unit.SOLUTION: Control for preventing dripping of condensate water is executed to reduce an amount of air flowing to an air outflow face 51a2 from an air inflow face 51a1 while taking a time, by rotating an indoor fan 55a1 at a prescribed rotating speed when a cooling operation is stopped, and lowering the rotating speed of the indoor fan 55a1 with a prescribed lowering ratio while taking a prescribed time from the time when the cooling operation is stopped to stop the indoor fan 55a1 at the lapse of the prescribed time. Thus the condensate water generating in an indoor heat exchanger 51a in the cooling operation and reaching the air inflow face 51a1 of the indoor heat exchanger 51a, is allowed to drip to a drain pan 57a similarly as that in the cooling operation, or can be dried.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an air conditioner, and more particularly to an air conditioner that can prevent water leakage from an indoor unit.

  In an air conditioner, a floor-mounted indoor unit may be used as an indoor unit connected to an outdoor unit through a refrigerant pipe. As for the floor-mounted indoor unit, a small one is installed in a closet of an air conditioning room, and a large one is installed outside the air conditioning room. The floor-mounted indoor unit has a housing having an air inlet and an air outlet, and an indoor heat exchanger, an indoor fan, and a drain pan are provided in the housing. The indoor heat exchanger and the indoor fan are arranged in the order of the indoor heat exchanger and the indoor fan in the air flow direction (the direction from the air inlet to the air outlet) in the housing, and the indoor heat exchanger is the air It is inclined at an angle so as to cross the flow. The drain pan is formed and arranged so as not to block the air inlet and to receive condensed water generated in the indoor heat exchanger during the cooling operation (see, for example, Patent Document 1).

  The air outlet of the floor-mounted indoor unit is connected to an air outlet duct having one end opened to the ceiling surface or wall surface of the air conditioning room. Further, when the floor-standing indoor unit is large, a suction duct having one end opened to the ceiling surface or wall surface of the air conditioning room is also connected to the air suction port. When the air conditioner starts operation, the air in the air conditioning room sucked into the housing from the air suction port by the rotation of the indoor fan is cooled or heated by exchanging heat with the refrigerant in the indoor heat exchanger. The air cooled or heated by the indoor heat exchanger is blown out from the air outlet through the blowout duct to the air conditioning room by the rotation of the indoor fan. In this way, the air conditioning room is cooled or heated.

JP-A-11-311421

  By the way, in the floor-mounted indoor unit described above, an air suction port is provided on the bottom surface of the casing and an air outlet is provided on the top surface of the casing, and an indoor fan is disposed in the vicinity of the air outlet in the casing. Some have an indoor heat exchanger disposed below. In such a floor-standing indoor unit, if the drain pan is disposed so as to cover the bottom surface of the casing of the indoor heat exchanger, the drain pan blocks the air suction port. In this case, the drain pan is disposed directly below the lower end portion of the indoor heat exchanger disposed at an inclination, and is formed so as to receive only condensed water dripping from the lower end portion.

  In the floor-mounted indoor unit having the above structure, the condensed water generated in the indoor heat exchanger during the cooling operation flows downward along the surface facing the bottom surface side of the indoor heat exchanger, Drip onto the drain pan from the lower end of the heat exchanger. This is to prevent the condensed water from dripping directly from the surface of the indoor heat exchanger facing the bottom side of the air that flows from the air inlet to the air outlet during the cooling operation due to the rotation of the indoor fan. This is because the condensed water, which is prevented from dripping directly under the air flow, flows downward along the surface facing the bottom surface side of the indoor heat exchanger.

  However, when the cooling operation is finished and the indoor fan is stopped, the air flow from the air inlet to the air outlet is eliminated. For this reason, the condensed water generated in the indoor heat exchanger at the end of the cooling operation may drop directly from the surface facing the bottom surface side of the indoor heat exchanger, and the dropped condensed water is below the indoor heat exchanger. There is a risk that the floor surface on which the floor-mounted indoor unit is installed leaks from the air suction port arranged in the room.

  The present invention solves the above-described problems, and an object of the present invention is to provide an air conditioner that does not drip from the condensed water indoor heat exchanger after the cooling operation is stopped in a floor-standing indoor unit.

  In order to solve the above-described problems, an air conditioner of the present invention has an indoor heat exchanger and an indoor fan in a housing having an air inlet and an air outlet, and air is supplied from the air inlet by the rotation of the indoor fan. An indoor unit in which the indoor heat exchanger is arranged obliquely with respect to the air flow toward the outlet, an outdoor unit connected to the indoor unit by a refrigerant pipe, and a cooling operation that causes the indoor heat exchanger to function as a condenser At the time of completion, the indoor fan is set to a predetermined number of rotations, and from the time of completion of the cooling operation, the number of rotations of the indoor fan is decreased from the predetermined number of rotations at a predetermined rate of decrease to stop the indoor fan. And a control means for executing condensate dripping prevention control.

  According to the air conditioner of the present invention configured as described above, when the cooling operation is stopped, the indoor fan is set to a predetermined rotation speed, and then the rotation speed of the indoor fan is decreased from the predetermined rotation speed at a predetermined decrease rate. After the cooling operation is stopped, the air flow to the indoor heat exchanger gradually decreases. Thereby, the condensed water which generate | occur | produced in the indoor heat exchanger can be prevented from dripping downward from the surface which faces the housing | casing bottom face of an indoor heat exchanger.

It is explanatory drawing of the air conditioning apparatus in embodiment of this invention, (A) is a refrigerant circuit figure, (B) is a block diagram of an indoor unit control means. It is explanatory drawing of the structure of the indoor unit in embodiment of this invention. It is a flowchart which shows the process which the indoor unit control means performs in embodiment of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an embodiment, three outdoor units installed in the air conditioning room or outside (in the following, referred to as indoor units except where necessary) are arranged in parallel with one outdoor unit installed outdoors. A description will be given by taking as an example an air conditioner that is connected to the air conditioner and can simultaneously perform cooling operation or heating operation in all indoor units. The present invention is not limited to the following embodiments, and can be variously modified without departing from the gist of the present invention. For example, one of the three indoor units may be a floor-standing indoor unit, and the remaining two units may be other types of indoor units such as a wall-mounted type or a ceiling-embedded type. Moreover, the indoor unit connected to an outdoor unit may be one floor-mounted indoor unit.

  As shown in FIG. 1A, an air conditioner 1 according to this embodiment includes one outdoor unit 2 that is installed outdoors, and an outdoor unit that is installed inside or outside an air conditioning room in a building. 2 includes three floor-mounted indoor units 5 a to 5 c connected in parallel by a liquid pipe 8 and a gas pipe 9. Specifically, the liquid pipe 8 has one end connected to the closing valve 25 of the outdoor unit 2 and the other end branched to be connected to the liquid pipe connecting portions 53a to 53c of the indoor units 5a to 5c. The gas pipe 9 has one end connected to the closing valve 26 of the outdoor unit 2 and the other end branched to be connected to the gas pipe connecting portions 54a to 54c of the indoor units 5a to 5c. The refrigerant circuit 100 of the air conditioner 1 is configured as described above.

  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. The refrigerant suction side of the compressor 21 is connected to the refrigerant outflow side of the accumulator 28 by a suction pipe 42.

  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 the outside air taken into the outdoor unit 2 by the rotation of the 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, and the amount of refrigerant flowing into the outdoor heat exchanger 23 or the amount of refrigerant flowing out of the outdoor heat exchanger 23 is adjusted by adjusting the opening thereof. The opening degree of the outdoor expansion valve 24 is fully opened when the air conditioner 1 is performing a cooling operation. In addition, when the air conditioner 1 is performing a heating operation, the opening temperature is controlled according to the discharge temperature of the compressor 21 detected by a discharge temperature sensor 33 described later, so that the discharge temperature has a performance upper limit value. I do not exceed it.

  The outdoor fan 27 is a propeller fan formed of a resin material, and is disposed in the vicinity of the outdoor heat exchanger 23. The outdoor fan 27 is rotated at a predetermined rotation speed by a fan motor having a variable rotation speed (not shown), thereby taking outside air into the outdoor unit 2 from a suction port (not shown), and the outside air exchanged heat with the refrigerant in the outdoor heat exchanger 23. Is discharged to the outside of the outdoor unit 2 from an air outlet (not shown).

  As described above, the accumulator 28 has the refrigerant inflow side connected to the port c of the four-way valve 22 and the refrigerant pipe 46, and the refrigerant outflow side is connected to the refrigerant intake side of the compressor 21 through the intake 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 a discharge pressure that is a pressure of the refrigerant discharged from the compressor 21, and a temperature of the refrigerant discharged from the compressor 21. A discharge temperature sensor 33 for detection 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 flowing into the outdoor unit 2, that is, the outside air temperature, is provided in the vicinity of a suction port (not shown) of the outdoor unit 2.

  Next, the three indoor units 5a to 5c will be described with reference to FIGS. The three indoor units 5a to 5c are liquid tubes in which the indoor heat exchangers 51a to 51c, the indoor expansion valves 52a to 52c, and the other end of the branched liquid tube 8 are connected to the inside of the casings 56a to 56c. Connection parts 53a-53c, gas pipe connection parts 54a-54c to which the other ends of the branched gas pipes 9 are connected, and drain pans 57a-57c are provided. And these apparatuses except indoor fan 55a-55c and drain pans 57a-57c are mutually connected by each refrigerant | coolant piping explained in full detail below, and comprise the indoor unit refrigerant circuit 50a-50c which makes a part of refrigerant circuit 100 doing.

  In addition, since the structure of all the indoor units 5a-5c is the same, in the following description, only the structure of the indoor unit 5a is demonstrated and description is abbreviate | omitted about the other indoor units 5b and 5c. In FIG. 1 and FIG. 2, what changed the end of the number given to the component apparatus of the indoor unit 5a from a to b or c becomes the component unit of the indoor units 5b and 5c corresponding to the component unit of the indoor unit 5a. .

  The casing 56a of the indoor unit 5a has a rectangular shape, and is formed by a bottom surface 56a1 and a top surface 56a2 shown in FIG. 2 and four side surfaces connecting these (in FIG. 2, two of these are drawn). The bottom surface 56a1 is provided with an air suction port 56a3, and the top surface 56a2 is provided with an air outlet 56a4. In the casing 56a, an indoor heat exchanger 52a and an indoor fan 55a are arranged in this order in the direction from the air inlet 56a3 toward the air outlet 56a4. As the indoor fan 55a rotates, the air taken into the housing 56a from the air inlet 56a3 flows toward the air outlet 56a4 and is blown out from the air outlet 56a4. The arrangement order of the indoor heat exchanger 52a and the indoor fan 55a may be reversed.

  The indoor heat exchanger 51a is formed in a flat plate shape, and is inclined from the air inlet 56a3 to the air outlet 56a4 by being inclined at a predetermined angle (for example, 50 degrees) with respect to the installation surface (floor surface) of the indoor unit 5a. It is arrange | positioned inside the housing | casing 56a so that the flow of the air which goes to may be crossed. With this arrangement, the surface on the air inlet 56a3 side of the indoor heat exchanger 51a becomes an air inflow surface 51a1 through which air flows in, and the surface on the air outlet 56a4 side has an air outflow surface 51a1 through which air flows out. Become. The indoor heat exchanger 51a exchanges heat between the refrigerant and the air in the air conditioning chamber taken into the housing 56a from the air suction port 56a3 by rotation of an indoor fan 55a described later.

  One end of the indoor unit liquid pipe 71a is connected to the lower end 51a3 of the indoor heat exchanger 51a, and the other end of the indoor unit liquid pipe 71a is connected to the liquid pipe connecting part 53a. One end of the indoor unit gas pipe 72a is connected to the upper end part 51a4 of the indoor heat exchanger 51a, and the other end of the indoor unit gas pipe 72a is connected to the gas pipe connection part 54a. 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. In addition, although illustration is abbreviate | omitted in FIG. 2, the liquid pipe connection part 53a and the gas pipe connection part 54a are provided in the side surface of the housing | casing 56a, and each of the liquid pipe connection part 53a and the gas pipe connection part 54a has each Refrigerant piping is 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. When the indoor heat exchanger 51a functions as an evaporator, the degree of opening of the indoor expansion valve 52a is that of the refrigerant at one refrigerant outlet (on the gas pipe connection portion 54a side) of the indoor heat exchanger 51a. The superheat degree is adjusted so as to become the target superheat degree. Further, when the indoor heat exchanger 51a functions as a condenser, the degree of opening of the indoor heat exchanger 51a is determined by the degree of supercooling of the refrigerant at the other refrigerant outlet (on the liquid pipe connection portion 53a side) of the indoor heat exchanger 51a being the target supercooling degree. It is adjusted to become. Here, the target degree of superheat and the target degree of supercooling are the degree of superheat of the refrigerant and the degree of supercooling of the refrigerant for exhibiting sufficient heating capacity or cooling capacity in the indoor unit 5a.

  The indoor fan 55a includes a cylindrical impeller 55a2 having a large number of blades, a casing 55a1 that accommodates the impeller 55a2 and includes an opening 55a3, and a fan motor that is not shown in the drawing and that rotates the impeller 55a2. ing. The casing 55a1 and the impeller 55a2 are each formed of a synthetic resin material. The indoor fan 55a is disposed in the vicinity of the air outlet 56a4 of the casing 56a, and the opening 55a3 of the casing 55a1 is connected to the inside of the casing 56a of the air outlet 56a4. Note that one end of the air outlet duct 300 is connected to the outside of the housing 56a of the air outlet 56a4, and the other end of the air outlet duct 300 is connected to an air outlet provided on the ceiling surface or wall surface of the air conditioning room. Yes. By rotating the indoor fan 55a, air is taken into the housing 56a from the air suction port 56a3, and the air that has exchanged heat with the refrigerant in the indoor heat exchanger 51a is discharged from the air outlet 56a4 through the blowout duct 300. To supply.

  Below the lower end 51a3 of the indoor heat exchanger 51a, a drain pan 57a that receives condensed water generated in the indoor heat exchanger 51a during cooling operation is provided. The drain pan 57a is formed of a synthetic resin material, and is formed in a box shape having a bottom surface and side surfaces extending from the four sides of the bottom surface and having an open top surface. As shown in FIG. 2, the drain pan 57a is disposed below the lower end 51a3 of the indoor heat exchanger 51a so as not to block the air suction port 56a3.

  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 in the vicinity of a suction port (not shown) of the indoor unit 5a.

  The indoor unit 5a is provided with 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, the indoor unit control means 500a includes a CPU 510a, a storage unit 520a, a communication unit 530a, and a sensor input unit 540a.

  The storage unit 520a is configured by a ROM or a RAM, and stores a detection value corresponding to the control program of the indoor unit 5a and detection signals from various sensors, the rotational speed of the indoor fan 55a, the opening of the indoor expansion valve 52a, and the like. doing. The communication unit 530a is an interface that performs communication with the outdoor unit 2. 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. Moreover, CPU510a takes in the control signal transmitted from the outdoor unit 2 via the communication part 530a. The CPU 510a transmits the cooling request capability or the heating request capability to the outdoor unit 2 via the communication unit 530a. Further, the CPU 510a controls the rotational speed of the indoor fan 55a and adjusts the opening of the indoor expansion valve 52a based on the acquired detection result and control signal.

  Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 100 when the air-conditioning apparatus 1 of the present embodiment performs the cooling operation will be described with reference to FIG. The refrigerant flow and the operation of each part in the refrigerant circuit 100 when the air conditioner 1 performs the heating operation are not directly related to the present invention, and thus a detailed description thereof will be omitted, and a simple explanation will be given after the explanation during the cooling operation. Keep in touch.

  As shown in FIG. 1A, when the indoor units 5a to 5c perform the cooling operation, the state where the four-way valve 22 is shown by a solid line, that is, the port a and the port b of the four-way valve 22 communicate with each other, The port c and the port d are switched so as to communicate with each other. As a result, the refrigerant circulates in the refrigerant circuit 100 in the direction indicated by the broken-line arrow, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchangers 51a to 51c 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 flows through the outdoor unit liquid pipe 44, and flows out to the liquid pipe 8 through the outdoor expansion valve 24 and the closing valve 25 that are fully opened.

  The refrigerant flowing through the liquid pipe 8 and flowing into the indoor units 5a to 5c through the liquid pipe connection portions 53a to 53c flows through the indoor unit liquid pipes 71a to 71c and is decompressed when passing through the indoor expansion valves 52a to 52c. And low pressure refrigerant. The refrigerant flowing into the indoor heat exchangers 51a to 51c from the indoor unit liquid pipes 71a to 71c is taken into the indoor units 5a to 5c from the air suction ports 56a3 to 56c3 by the rotation of the indoor fans 55a to 55c. Evaporates by exchanging heat with air. Thus, the indoor heat exchangers 51a to 51c function as evaporators, and the air that has exchanged heat with the refrigerant in the indoor heat exchangers 51a to 51c is air-conditioned from the air outlets 56a4 to 56c4 through the outlet duct 300. The air conditioning room is cooled by being blown out.

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

  When the indoor units 5a to 5c perform the heating operation, the four-way valve 22 is in a state 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. To be switched. As a result, the refrigerant circulates in the refrigerant circuit 100 in a direction opposite to the refrigerant flow direction during the cooling operation except for the space between the compressor 21 and the four-way valve 22, and the outdoor heat exchanger 23 serves as an evaporator. The indoor heat exchangers 51a to 51c function as a condenser while functioning.

  When the air conditioning apparatus 1 performs the above-described cooling operation, condensed water is generated in the indoor heat exchangers 51a to 51c functioning as condensers. The generated condensed water reaches the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c by gravity. On the other hand, as shown in FIG. 2, during the cooling operation, the air that has flowed into the housings 56a to 56c from the air suction ports 56a3 to 56c3 due to the rotation of the indoor fans 55a to 55c is the air in the indoor heat exchangers 51a to 51c. It flows from the inflow surfaces 51a1 to 51c1 to the air outflow surfaces 51a2 to 51c2.

  Therefore, the condensed water which reaches the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c and drops downward from the air inflow surfaces 51a1 to 51c1 (by the air suction ports 56a3 to 56c3) due to gravity is exchanged indoors. Dropping is blocked by the air passing through the air inflow surfaces 51a1 to 51c1 from the air inflow surfaces 51a1 to 51c1, and the lower ends 51a3 to 51c of the indoor heat exchangers 51a to 51c through the air inflow surfaces 51a1 to 51c1. It flows toward 51c3. And it is dripped at the drain pans 57a-57c from lower end part 51a3-51c3. That is, during cooling operation, the rotation of the indoor fans 55a to 55c prevents the condensed water from dripping from the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c.

  However, since the indoor fans 55a to 55c are also stopped when the cooling operation is stopped, there is no flow of air passing through the indoor heat exchangers 51a to 51c from the air inflow surfaces 51a1 to 51c1 to the air outflow surfaces 51a2 to 51c2. As a result, the condensed water generated in the indoor heat exchangers 51a to 51c during the cooling operation and reaching the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c is dropped downward from the air intake ports 56a3 to 56c3. Since it drops on the floor surface, when the cooling operation is stopped, the condensed water may leak from the indoor units 5a to 5c to the floor surface of the air conditioning room.

  Therefore, in the present invention, the indoor fans 55a1 to 55c1 are set to a predetermined rotational speed when the cooling operation is stopped, and the rotational speeds of the indoor fans 55a1 to 55c1 are decreased from the predetermined rotational speed at a predetermined decrease rate from the time when the cooling operation is stopped. Then, by stopping the indoor fans 55a1 to 55c1, the condensed water dripping prevention control is performed to reduce the amount of air flowing from the air inflow surfaces 51a1 to 51c1 to the air outflow surfaces 51a2 to 51c2 over time. By performing the condensed water dripping prevention control, the condensed water generated in the indoor heat exchangers 51a to 51c during the cooling operation and reaching the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c is the same as during the cooling operation. Can be dripped onto the drain pans 57a to 57c or dried, so that the condensed water is prevented from dripping downward from the indoor heat exchangers 51a to 51c and dripping from the air suction ports 56a3 to 56c3 onto the floor surface. Can do.

  Here, the predetermined rotational speed (hereinafter referred to as the predetermined rotational speed Rp) that is the rotational speed of the indoor fans 55a1 to 55c1 when the condensed water dripping prevention control is performed, and the predetermined reduction rate when the rotational speed is decreased from the predetermined rotational speed Rp. (Hereinafter referred to as a predetermined rate of decrease Rr) is a numerical value obtained in advance by performing tests or the like and stored in the storage units 520a to 520c of the indoor unit control means 500a to 500c. These numerical values indicate that the indoor fans 55a1 to 55c1 are set to a predetermined rotational speed Rp (for example, 500 rpm) when the cooling operation is stopped, and then the indoor heat exchange is performed when the rotational speed is decreased at a predetermined reduction rate Rr (for example, 100 rpm / minute). It is a numerical value that has been confirmed to prevent dripping of condensed water from the indoor heat exchangers 51a to 51c even when the maximum amount of condensed water is generated in the vessels 51a to 51c.

  Next, processing when performing the above-described condensed water dripping prevention control will be described with reference to FIG. FIG. 3 shows a flow of processing relating to control performed by the CPUs 510a to 510c of the indoor unit control means 500a to 500c during the cooling operation. In the flowchart shown in FIG. 3, ST represents a step, and the number following this represents a step number. In this flowchart, the processing related to the present invention is mainly described. Other processing, for example, control of the rotational speed of the compressor 21 according to the temperature difference between the set temperature and the room temperature, and the temperature of the refrigerant. Description of general processing related to the air conditioner 1 such as the opening control of the outdoor expansion valve 24 and the indoor expansion valves 52a to 52c is omitted.

  When the air conditioner 1 starts operation, the CPUs 510a to 510c determine whether or not the user has instructed the cooling operation by means such as using a remote controller of the indoor units 5a to 5c (not shown) (ST1). If it is the instruction | indication of air_conditionaing | cooling operation (ST1-Yes), CPU210 will perform air_conditionaing | cooling operation start processing (ST2), and will perform air_conditionaing | cooling operation control after that (ST3).

  Here, the cooling operation start processing means that the CPUs 510a to 510c transmit the cooling operation to the outdoor unit 2 via the communication units 530a to 530c, and the outdoor unit 2 that has received the operation operates the four-way valve 22. The refrigerant circuit 100 is in the state shown in FIG. 1A, that is, the refrigerant circuit 100 is in a cooling cycle, which is a process executed when the cooling operation is first performed.

  In the cooling operation control, the CPUs 510a to 510c control the rotation speed of the indoor fans 55a to 55c and adjust the opening of the indoor expansion valves 52a to 52c according to the cooling request capability by the user, and communicate the cooling request capability. It transmits to the outdoor unit 2 via the units 530a to 530c. The outdoor unit 2 that has received the cooling request capability is controlled so as to drive the compressor 21 and the outdoor fan 27 at a rotational speed corresponding to the received cooling request capability.

  When the cooling operation control is performed as described above, the CPUs 510a to 510c determine whether or not there is an operation switching instruction from the user (ST4). Here, the operation switching instruction is switching from the cooling operation to the heating operation, or switching from the heating operation to the cooling operation. If there is an operation switching instruction (ST4-Yes), CPUs 510a to 510c return the process to ST1. If there is no operation switching instruction (ST4-No), the CPUs 510a to 510c determine whether or not there is an operation stop instruction from the user (ST5).

  If there is no operation stop instruction (ST5-No), the CPUs 510a to 510c determine whether or not the current operation is a cooling operation (ST13). If the current operation is the cooling operation (ST13-Yes), the CPUs 510a to 510c return the process to ST3, and if the current operation is not the cooling operation (ST13-No), the CPU 210 returns the process to ST14.

  If there is an operation stop instruction (ST5-Yes), the CPUs 510a to 510c close the indoor expansion valves 52a to 52c (ST6) and determine whether or not the cooling operation has been performed until the operation stop instruction is received in ST5 (ST7). ).

  If the cooling operation has not been performed (ST7-No), that is, if the heating operation has been performed, the CPUs 510a to 510c stop the indoor fans 55a to 55c (ST12), and the processing is terminated. If the cooling operation has been performed (ST7-Yes), the CPUs 510a to 510c set the rotational speed of the indoor fans 55a to 55c to the predetermined rotational speed Rp, and then rotate the indoor fans 55a to 55c at a predetermined reduction rate Rr. The number is decreased (ST8).

  Next, the CPUs 510a to 510c determine whether or not the rotational speed of the indoor fans 55a to 55c has become 0 (ST9). If the rotational speed is not 0 (ST9-No), the CPUs 510a to 510c return the process to ST9 and continuously reduce the rotational speeds of the indoor fans 55a to 55c at a predetermined reduction rate Rr.

  If the number of rotations is 0 in ST9 (ST9-Yes), the CPUs 510a to 510c end the process. In addition, the process of ST8 and ST9 demonstrated above is a process in connection with the condensed water dripping prevention control of this invention.

  In ST1, if it is not a cooling operation instruction (ST1-No), that is, if it is a heating operation instruction, the CPUs 510a to 510c perform a heating operation start process (ST10), and then execute the heating operation control. The process proceeds to (ST11) and ST4.

  Here, the heating operation start processing is that the CPUs 510a to 510c transmit the heating operation to the outdoor unit 2 via the communication units 530a to 530c, and the outdoor unit 2 that has received the operation operates the four-way valve 22. This is to make the refrigerant circuit 100 a heating cycle, and is a process executed when the heating operation is first performed.

  The heating operation control means that the CPUs 510a to 510c perform the rotation speed control of the indoor fans 55a to 55c and the opening adjustments of the indoor expansion valves 52a to 52c according to the heating request capability by the user, and communicate the heating request capability. It transmits to the outdoor unit 2 via the units 530a to 530c. This is to control the outdoor unit 2 that has received the heating request capability to drive at the number of revolutions corresponding to the heating request capability that has received the compressor 21 and the outdoor fan 27.

  As described above, in the air conditioner 1 of the present invention, when the cooling operation is stopped, the indoor fans 55a to 55c are set to the predetermined rotational speed Rp, and then the rotational speeds of the indoor fans 55a to 55c are set at the predetermined decrease rate Rr. And the indoor fans 55a to 55c are stopped to perform the condensed water dripping prevention control for reducing the amount of air flowing from the air inflow surfaces 51a1 to 51c1 to the air outflow surfaces 51a2 to 51c2 over time. Thereby, the condensed water generated in the indoor heat exchangers 51a to 51c during the cooling operation and reaching the air inflow surfaces 51a1 to 51c1 of the indoor heat exchangers 51a to 51c is dropped or dried on the drain pans 57a to 57c. It is possible to prevent the condensed water from dropping from the indoor heat exchangers 51a to 51c and dropping from the air suction ports 56a3 to 56c3 to the floor surface. Further, in the condensate dripping prevention control of the present invention, the rotational speed of the indoor fans 55a to 55c is reduced at a predetermined reduction rate Rr after the cooling operation is stopped, so that the indoor fans 55a to 55c are controlled even though the operation is stopped. The uncomfortable feeling that the user feels, such as being blown by rotation and the sound of rotation of the indoor fans 55a to 55c, is alleviated.

  In the embodiment described above, the case where the predetermined rotation speed Rp determined by performing a test or the like in advance is used as the predetermined rotation speed has been described. However, the rotation speed of the indoor fans 55a to 55c at the end of the cooling operation is predetermined. It is good also as a rotation speed. Thereby, in the process of ST8 in the flowchart of FIG. 3, it is not necessary to control the rotational speed of the indoor fans 55a to 55c to be a predetermined rotational speed Rp, so that the burden on the CPUs 510a to 510c can be reduced.

  Further, as described above, when the rotation speed of the indoor fans 55a to 55c at the end of the cooling operation is set to the predetermined rotation speed, the predetermined number is set according to the predetermined rotation speed instead of the predetermined decrease rate Rr. By changing the decrease rate of the indoor fan 55a to 55c, the time for reducing the rotational speed of the indoor fans 55a to 55c from the predetermined rotational speed to 0, that is, the execution time of the condensed water dripping prevention control starting from the end of the cooling operation is set to the predetermined rotational speed. Regardless, it may be constant. Thereby, since the time for which the indoor fans 55a to 55c rotate from the end of the cooling operation becomes constant, it is possible to reduce a sense of discomfort felt by the user while preventing dripping of the condensed water.

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 2 Outdoor unit 5a-5c Indoor unit 51a-51c Indoor heat exchanger 51a1-51c1 Air inflow surface 51a2-51c2 Air outflow surface 51a3-51c3 Lower end part 51a4-51c4 Upper end part 52a-52c Indoor expansion valve 55a-55c Indoor fan 55a3-55c3 Opening 56a-56c Housing 56a1-56c1 Bottom 56a2-56c2 Top 56a3-56c3 Air inlet 56a4-56c4 Air outlet 57a-57c Drain pan 71a-71c Indoor unit liquid pipe 72a-72c Indoor unit gas Pipe 300 Blowout duct 500a-500c Indoor unit control part 510a-510c CPU
520a to 520c Storage unit Rp Predetermined rotation speed Rr Predetermined decrease rate tp Predetermined time

Claims (3)

An indoor heat exchanger and an indoor fan are provided in a housing having an air inlet and an air outlet, and the room is inclined with respect to the flow of air from the air inlet to the air outlet by the rotation of the indoor fan. An indoor unit in which a heat exchanger is disposed;
An outdoor unit connected to the indoor unit by a refrigerant pipe;
When the cooling operation performed by causing the indoor heat exchanger to function as a condenser is completed, the indoor fan is set to a predetermined rotation speed, and the rotation speed of the indoor fan is set to the predetermined rotation from the completion of the cooling operation. Control means for performing condensation water dripping prevention control for lowering the indoor fan at a predetermined reduction rate determined from the number and stopping the indoor fan;
An air conditioner characterized by comprising: The predetermined rotational speed is the rotational speed of the indoor fan at the end of the cooling operation.
The air conditioner according to claim 1.   The air conditioner according to claim 2, wherein the predetermined decrease rate is changed according to the predetermined rotation speed.

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