AIR CONDITIONING UNIT AND AIR CONDITIONING SYSTEM

TECHNICAL FIELD

The present invention relates to an air conditioning unit that blows out temperature-controlled air to a front side indoors.

BACKGROUND

There is a conventional air conditioning unit having a rectangular shape in front view.

For example, an indoor unit disclosed in Patent Literature 1 (JP 2017-146011 A) includes a casing having a rectangular box-like shape and blows out air after heat exchange toward the front. Further, Patent Literature 1 (JP 2017-146011 A) also discloses a configuration in which the four indoor units are arranged.

It may be required that air blown out of an air conditioning unit which is disposed indoors reach far.

SUMMARY

An air conditioning unit according to one or more embodiments blows out temperature-controlled air to a front side indoors. The air conditioning unit includes a fan, a casing, and an air passage forming member. The fan is stored in the casing. The air passage forming member is disposed on an air-flow downstream side of the fan. An air passage of the air passage forming member has a circular cross-sectional shape. The casing has a rectangular shape in front view (i.e., when viewed from a front direction of the casing). The rectangular shape is surrounded by a first side and a second side, the first side and the second side being parallel to each other, and a third side and a fourth side, the third side and the fourth side being parallel to each other. In the air conditioning unit, a smaller one of a first distance between the first side and the second side and a second distance between the third side and the fourth side is equal to or smaller than 2.5 times a diameter of a cross section of the air passage.

As described above, in the air conditioning unit, a ratio of the smaller one of the first distance and the second distance to the diameter of the cross section of the air passage is smaller than a conventional ratio. Thus, for example, when the first distance is smaller than the second distance, the first distance is reduced to a short distance equal to or smaller than 2.5 times the diameter of the cross section of the air passage. In this case, when a plurality of air conditioning units are arranged in an extending direction of the third side and the fourth side, a distance in front view between the air passage of a first air conditioning unit and the air passage of a second air conditioning unit which are adjacent to each other is reduced. Accordingly, air blown out through the air passage of the first air conditioning unit and air blown out through the air passage of the second air conditioning unit both play a role for reducing air flow resistance each other, and can reach far.

In an air conditioning unit according to one or more embodiments, the smaller one of the first distance and the second distance is equal to or smaller than 2.0 times the diameter of the cross section of the air passage.

In one or more embodiments, for example, when the first distance is smaller than the second distance, the first distance is reduced to a short distance equal to or smaller than 2.0 times the diameter of the cross section of the air passage, which is much shorter than a conventional distance. Thus, when a plurality of air conditioning units are arranged in the extending direction of the third side and the fourth side, air blown out through each of the air passages can reach extremely far.

An air conditioning unit according to one or more embodiments further includes a drain pan that receives condensed dew generated inside the casing. The drain pan is disposed in a lower part of an internal space of the casing. The first side and the second side of the casing extend in a horizontal direction (i.e., in a width direction of the casing). The third side and the fourth side of the casing extend in a vertical direction (i.e., in a height direction of the casing). The first distance corresponding to a height dimension of the casing is smaller than the second distance corresponding to a width dimension of the casing.

In one or more embodiments, in the air conditioning unit including the casing having the height dimension (first distance) smaller than the width dimension (second distance), the drain pan is disposed in the lower part of the internal space of the casing. In a conventional air conditioning unit provided with a drain pan, design for reducing the height dimension of the casing (first distance) to a short distance equal to or smaller than 2.5 times the diameter of the cross section of the air passage has not been made. That is, design having the diameter of the cross section of the air passage equal to or larger than 40% of the height dimension of the casing (first distance) is not easy in view of the arrangement of the drain pan and the like, and has not been conventionally conceived. However, the air conditioning unit according to one or more embodiments employs the configuration for reducing the height dimension (first distance) of the casing with respect to the diameter of the cross section of the air passage. Thus, the above effect of causing blown-out air to reach far can be obtained.

An air conditioning system according to one or more embodiments includes a first air conditioning unit and a second air conditioning unit that are arranged in a first direction. The first air conditioning unit is the air conditioning unit according to the embodiments described above. The second air conditioning unit is also the air conditioning unit according to the embodiments described above. A center of a first air passage that is the air passage of the first air conditioning unit and a center of a second air passage that is the air passage of the second air conditioning unit are separated from each other by a third distance in the first direction. The third distance is equal to or smaller than 2.5 times the diameter of the cross section of the air passage.

In one or more embodiments, the air conditioning unit according to the embodiments described above is employed as each of the first air conditioning unit and the second air conditioning unit. Thus, it is possible to reduce the third distance to equal to or smaller than 2.5 times the diameter of the cross section of the air passage. Further, since the third distance between the center of the first air passage and the center of the second air passage is equal to or smaller than 2.5 times the diameter of the cross section of the air passage and thus relatively small, air blown out through the first air passage and air blown out through the second air passage both play a role for reducing air flow resistance each other. Accordingly, in the air conditioning system according to one or more embodiments, air blown out through the first air passage and air blown out through the second air passage both reach farther as compared to a conventional case.

An air conditioning system according to one or more embodiments further includes a support member. The support member is disposed between the first air conditioning unit and the second air conditioning unit. The support member supports the first air conditioning unit and/or the second air conditioning unit. A dimension of the support member in the first direction is equal to or smaller than half the diameter of the cross section of the air passage.

In one or more embodiments, the support member is used as a member which supports the first air conditioning unit and/or the second air conditioning unit. Further, the dimension of the support member in the first direction is reduced. Thus, it is possible to bring the center of the first air passage and the center of the second air passage close to each other. This reduces the third distance and makes it easy for air blown out through the first air passage and air blown out through the second air passage to reach far.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed in color. Copies of this patent or application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

FIG. 1 is a diagram illustrating a refrigerant pipe system of an air conditioning system.

FIG. 2 is a diagram illustrating part of an internal structure of a use-side air conditioning unit viewed from obliquely behind.

FIG. 3 is a front view of the air conditioning unit.

FIG. 4 is a side view of the air conditioning unit.

FIG. 5 is a diagram illustrating a state in which two air conditioning units are arranged in a vertical direction.

FIG. 6 is a diagram illustrating a unit distance when the two air conditioning units are arranged in the vertical direction.

FIG. 7 is a diagram illustrating a result of a fluid analysis when a use-side fan is rotated.

FIG. 8 is a diagram illustrating a flow state (an air velocity distribution, a turbulent flow energy) on a blow-out surface in the result of the fluid analysis of FIG. 7.

FIG. 9 is a diagram illustrating another analysis result obtained by inputting the flow state of FIG. 8 to a blow-out boundary surface.

FIG. 10 is a diagram of an analysis result illustrating the farthest distance traveled by blown-out air flowing at a predetermined air velocity (a blow distance at an air velocity of 1 m/s or higher) in a case where the two air conditioning units which are largely separated from each other are operated.

FIG. 11 is a diagram of an analysis result illustrating the farthest distance traveled by blown-out air flowing at the predetermined air velocity (the blow distance at an air velocity of 1 m/s or higher) in a case where the two air conditioning units which are closely disposed are operated.

FIG. 12 is a diagram of an analysis result illustrating the farthest distance traveled by blown-out air flowing at the predetermined air velocity (the blow distance at an air velocity of 1 m/s or higher) in a case where the two air conditioning units which are adjacently disposed are operated.

FIG. 13 is a graph illustrating the relationship between the blow distance at an air velocity of 1 m/s or higher, the distance between air passages, and the air passage diameter.

FIG. 14 is a diagram of an analysis result illustrating the farthest distance traveled by blown-out air flowing at a predetermined air velocity (a blow distance at an air velocity of 1 m/s or higher) in a case where four air conditioning units are adjacently disposed according to a modification.

DETAILED DESCRIPTION

(1) Entire Configuration of Air Conditioning System

FIG. 1 is a diagram illustrating a refrigerant pipe system of an air conditioning system 10. The air conditioning system 10 is a separate type air conditioning apparatus with a refrigerant pipe system, and cools and heats inside of a building by performing a vapor compression refrigeration cycle operation.

The air conditioning system 10 is mainly installed in a factory in order to partially cool or heat a space inside an open building such as a factory. The air conditioning system 10 includes a heat source unit 11, which is installed outside the factory, a large number of air conditioning units 12A, 12B, . . . , which are installed inside the factory, and a liquid-refrigerant connection pipe 13 and a gas-refrigerant connection pipe 14, which connect the heat source unit 11 to the air conditioning units 12A, 12B, . . . . In other words, a refrigerant circuit of the air conditioning system 10 illustrated in FIG. 1 includes the heat source unit 11, the use-side air conditioning units 12A, 12B, . . . , and the refrigerant connection pipes 13, 14 which are connected to each other.

Inside the factory, the air conditioning units 12A, 12B, . . . may be placed on a floor surface, suspended from a beam in a ceiling, or supported on a pillar. A remote controller (not illustrated) is connected to each of the air conditioning units 12A, 12B, . . . so that a set temperature and an airflow volume can be changed in several stages. Further, the air conditioning units 12A, 12B, . . . can be individually turned on and off.

A refrigerant is sealed inside the refrigerant circuit illustrated in FIG. 1. As described later, a refrigeration cycle operation in which the refrigerant is compressed, cooled and condensed, decompressed, heated and evaporated, and then compressed again is performed.

(2) Configuration of Each Unit of Air Conditioning System

(2-1) Heat Source Unit

The heat source unit 11 mainly includes a compressor 20, a four-way switching valve 15, a heat-source-side heat exchanger 30, a heat-source-side expansion valve 41, a liquid-side shutoff valve 17, and a gas-side shutoff valve 18.

The compressor 20 is a hermetic compressor which is driven by a compressor motor. The compressor 20 sucks a gas refrigerant in through a suction flow path 27.

The four-way switching valve 15 is a mechanism for switching a refrigerant flow direction. In a cooling operation, the four-way switching valve 15 connects a refrigerant pipe 29 on the discharge side of the compressor 20 and one end of the heat-source-side heat exchanger 30 and connects the suction flow path 27 on the suction side of the compressor 20 and the gas-side shutoff valve 18 (refer to solid lines on the four-way switching valve 15 of FIG. 1). Accordingly, the heat-source-side heat exchanger 30 functions as a condenser for the refrigerant compressed by the compressor 20, and a use-side heat exchanger 50 (described later) functions as an evaporator for the refrigerant condensed in the heat-source-side heat exchanger 30. Further, in a heating operation, the four-way switching valve 15 connects the refrigerant pipe 29 on the discharge side of the compressor 20 and the gas-side shutoff valve 18 and connects the suction flow path 27 and one end of the heat-source-side heat exchanger 30 (refer to broken lines on the four-way switching valve 15 of FIG. 1). Accordingly, the use-side heat exchanger 50 functions as a condenser for the refrigerant compressed by the compressor 20, and the heat-source-side heat exchanger 30 functions as an evaporator for the refrigerant cooled in the use-side heat exchanger 50.

The heat-source-side heat exchanger 30 is a heat exchanger which functions as a condenser or an evaporator for the refrigerant. One end of the heat-source-side heat exchanger 30 is connected to the four-way switching valve 15, and the other end thereof is connected to the heat-source-side expansion valve 41.

The heat source unit 11 includes a heat-source-side fan 35 for taking outside air into the unit and discharging the air to the outside again.

The heat-source-side expansion valve 41 is an expansion mechanism for decompressing the refrigerant. The heat-source-side expansion valve 41 is an electronic expansion valve whose opening degree is adjustable. One end of the heat-source-side expansion valve 41 is connected to the heat-source-side heat exchanger 30, and the other end thereof is connected to the liquid-side shutoff valve 17.

The liquid-side shutoff valve 17 is a valve to which the liquid-refrigerant connection pipe 13 is connected. The gas-side shutoff valve 18 is a valve to which the gas-refrigerant connection pipe 14 is connected, and the gas-side shutoff valve 18 is also connected to the four-way switching valve 15.

(2-2) Use-Side Air Conditioning Unit

Each of the air conditioning units 12A, 12B, . . . is connected to the heat source unit 11 through the refrigerant connection pipes 13, 14. All the air conditioning units 12A, 12B, . . . have completely the same outer shape and internal structure. Hereinbelow, the air conditioning unit 12A will be described as an example with reference to FIGS. 1 to 4.

The air conditioning unit 12A includes a liquid-refrigerant pipe 51, a use-side expansion valve 42, which is a decompressor, the use-side heat exchanger 50, a gas-refrigerant pipe 52, a use-side fan 55, and the like.

The use-side expansion valve 42 is an expansion mechanism for decompressing the refrigerant. The use-side expansion valve 42 is an electronic expansion valve whose opening degree is adjustable. One end of the use-side expansion valve 42 is connected to the liquid-refrigerant connection pipe 13 through the liquid-refrigerant pipe 51, and the other end thereof is connected to the use-side heat exchanger 50.

The use-side heat exchanger 50 is a heat exchanger which functions as an evaporator or a condenser for the refrigerant. One end of the use-side heat exchanger 50 is connected to the use-side expansion valve 42, and the other end thereof is connected to the gas-refrigerant connection pipe 14 through the gas-refrigerant pipe 52.

The air conditioning unit 12A includes the use-side fan 55 for taking indoor air into the unit and supplying the air indoors again, and exchanges heat between the indoor air and the refrigerant flowing through the use-side heat exchanger 50.

(2-3) Refrigerant Connection Pipe

The refrigerant connection pipes 13, 14 are refrigerant pipes which are constructed on a site where the heat source unit 11 and the air conditioning units 12A, 12B, . . . are installed in an installation place inside or outside the factory. When the use-side air conditioning units 12A, 12B, . . . described above are installed, the use-side air conditioning units 12A, 12B, . . . are directly mounted on the floor surface of the factory or a base, suspended from the ceiling beam with extension ducts connected to blow-out ports thereof, or vertically arranged on the pillar. With the installation of the air conditioning units 12A, 12B, . . . , the refrigerant connection pipes 13, 14 are also disposed along the underfloor, the ceiling, or the pillar.

Note that a manual valve disposed between the refrigerant connection pipes 13, 14 and the air conditioning units 12A, 12B, . . . facilitates additional installation or relocation of the air conditioning unit in the future.

In the air conditioning system 10, several tens of air conditioning units 12A, 12B, . . . can be connected to the heat source unit 11, and the maximum length of the refrigerant connection pipes 13, 14 is 150 m.

(3) Operation of Air Conditioning System

Next, the operation of the air conditioning system 10 will be described.

(3-1) Operation in Cooling Operation

In the cooling operation, the four-way switching valve 15 is in the state indicated by the solid lines in FIG. 1, that is, the state in which the gas refrigerant discharged from the compressor 20 flows to the heat-source-side heat exchanger 30, and the suction flow path 27 is connected to the gas-side shutoff valve 18. The heat-source-side expansion valve 41 is in a fully open state, and the opening degree of the use-side expansion valve 42 is adjusted. The shutoff valves 17, 18 are in an open state.

In this refrigerant circuit state, a high-pressure gas refrigerant discharged from the compressor 20 is fed to the heat-source-side heat exchanger 30, which functions as a condenser for the refrigerant, through the four-way switching valve 15, and cooled by heat exchange with outside air supplied by the heat-source-side fan 35. The high-pressure refrigerant cooled and liquefied in the heat-source-side heat exchanger 30 is fed to each of the air conditioning units 12A, 12B, . . . through the liquid-refrigerant connection pipe 13. The refrigerant fed to each of the air conditioning units 12A, 12B, . . . becomes a low-pressure refrigerant in a gas-liquid two-phase state by being decompressed by the use-side expansion valve 42, and evaporates and becomes a low-pressure gas refrigerant by heat exchange with indoor air in the use-side heat exchanger 50, which functions as an evaporator for the refrigerant. Then, the low-pressure gas refrigerant heated in the use-side heat exchanger 50 is fed to the heat source unit 11 through the gas-refrigerant connection pipe 14, and sucked into the compressor 20 again through the four-way switching valve 15. Cooling inside the factory (indoors) is performed in this manner.

When only some of the air conditioning units 12A, 12B, . . . are operated, the opening degree of the use-side expansion valve 42 of each stopped air conditioning unit is set to a stop opening degree. In this case, the refrigerant hardly passes through the inside of each air conditioning unit whose operation is at a stop, and the cooling operation is performed only in each air conditioning unit in operation.

(3-2) Operation in Heating Operation

In the heating operation, the four-way switching valve 15 is in the state indicated by the broken lines in FIG. 1, that is, the state in which the refrigerant pipe 29 on the discharge side of the compressor 20 is connected to the gas-side shutoff valve 18, and the suction flow path 27 is connected to the heat-source-side heat exchanger 30. The opening degrees of the heat-source-side expansion valve 41 and the use-side expansion valve 42 are adjusted. The shutoff valves 17, 18 are in an open state.

In this refrigerant circuit state, a high-pressure gas refrigerant discharged from the compressor 20 is fed to each of the air conditioning units 12A, 12B, . . . through the four-way switching valve 15 and the gas-refrigerant connection pipe 14. Then, the high-pressure refrigerant fed to each of the air conditioning units 12A, 12B, . . . is cooled by heat exchange with indoor air in the use-side heat exchanger 50, which functions as a condenser for the refrigerant, then passes through the use-side expansion valve 42, and is fed to the heat source unit 11 through the liquid-refrigerant connection pipe 13. When the refrigerant is cooled by heat exchange with indoor air, the indoor air is heated. The high-pressure refrigerant fed to the heat source unit 11 becomes a low-pressure refrigerant in a gas-liquid two-phase state by being decompressed by the heat-source-side expansion valve 41, and flows into the heat-source-side heat exchanger 30, which functions as an evaporator for the refrigerant. The low-pressure refrigerant in a gas-liquid two-phase state flowing into the heat-source-side heat exchanger 30 is heated by heat exchange with outside air supplied by the heat-source-side fan 35, and evaporates and becomes a low-pressure refrigerant. The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 30 is sucked into the compressor 20 again through the four-way switching valve 15. Heating inside the factory (indoor) is performed in this manner.

(4) Details of Structure of Use-Side Air Conditioning Unit

Next, details of the use-side air conditioning units 12A, 12B, . . . will be described. As described above, all the air conditioning units have the same outer shape and the same internal structure. Thus, the air conditioning unit 12A will be described as an example.

The air conditioning unit 12A is a unit which blows out temperature-controlled air to the front side indoors. The air conditioning unit 12A includes first and second air passage forming members 71, 72, a drain pan 59, and a casing 60, and the like, in addition to the liquid-refrigerant pipe 51, the use-side expansion valve 42, which serves as a decompressor, the use-side heat exchanger 50, the gas-refrigerant pipe 52, and the use-side fan 55. FIG. 2 is a diagram illustrating part of the internal structure of the air conditioning unit 12A viewed from obliquely behind. In FIG. 2, an electric component box, the use-side expansion valve 42, and a large part of each of the liquid-refrigerant pipe 51 and the gas-refrigerant pipe 52 are not illustrated in order to make other parts of the internal structure easier to see. Further, in order to facilitate understanding, for example, a part of the first air passage forming member 71, which is the part covering the periphery of a fan blade 55b, is also not illustrated, and only a part of a front-side part of the first air passage forming member 71 is illustrated.

(4-1) Use-Side Heat Exchanger and Use-Side Fan

As illustrated in FIG. 2, the use-side heat exchanger 50 is disposed on the back side inside the casing 60. In FIG. 2, the right side corresponds to the front side, and the left side corresponds to the back side. The use-side fan 55 is located in front of the use-side heat exchanger 50. The use-side fan 55 includes a motor 55a, which has a shaft extending front and back, and the fan blade 55b, which is located in front of the motor 55a. When the fan blade 55b rotates, air is sucked in through an opening on the back face of the casing 60, and the air flows from the back side to the front side of the use-side heat exchanger 50. The air passing through the use-side heat exchanger 50 passes through a blow-out port 66, which is located on the front side of the use-side fan 55, and is blown out to the front side of the casing 60.

(4-2) First and Second Air Passage Forming Members

Each of the first and second air passage forming members 71, 72 is a cylindrical member. The first air passage forming member 71 is located inside the casing 60, and covers the periphery of the fan blade 55b. As illustrated in FIGS. 3 and 4, the second air passage forming member 72 is located outside the casing 60, and guides air blown out through the blow-out port 66 to the front. The second air passage forming member 72 is disposed on the air-flow downstream side of the use-side fan 55. The first air passage forming member 71 and the second air passage forming member 72 have the same inner diameter ID. The first and second air passage forming members 71, 72 form an air passage FS1 having a cylindrical shape on the front side of the fan blade 55b. A diameter D of the air passage FS1 is equal to the inner diameter ID of the first and second air passage forming members 71, 72 (refer to FIG. 3).

In one or more embodiments, the diameter of the cross section of the second air passage forming member 72, which is located on the air-flow downstream side relative to the fan blade 55b, is constant. Alternatively, a structure in which the diameter of the cross section of the second air passage forming member 72 decreases toward the tip thereof may be employed. However, in this case, since the diameter of the cross section of the tip part of the air passage FS1 becomes small, it becomes difficult to satisfy a condition of the ratio to a height dimension H of the casing 60 (described later).

(4-3) Drain Pan

As illustrated in FIG. 2, the drain pan 59 is disposed in the lower part inside the casing 60. The drain pan 59 is located under the use-side heat exchanger 50, the liquid-refrigerant pipe 51, the gas-refrigerant pipe 52, the use-side fan 55, and the first air passage forming member 71 and the like, and receives condensed dew generated inside the casing 60. In the cooling operation, even when dew condensation occurs on the surfaces of the use-side heat exchanger 50 and the liquid-refrigerant pipe 51, the drain pan 59 can receive the condensed dew.

(4-4) Casing

The casing 60 having a rectangular box-like shape mainly includes a top plate 61, a bottom plate 62, a left-side plate 63, a right-side plate 64, and a front plate 65. No steel plate is present on the back face of the casing 60 so that the back face of the use-side heat exchanger 50 is exposed. The blow-out port 66 having a circular shape is formed on the center of the front plate 65. A plurality of straightening plates are disposed on the blow-out port 66. Further, the diameter of the blow-out port 66 is equal to the inner diameter ID of the first and second air passage forming members 71, 72 described above.

As illustrated in FIG. 3, the casing 60 has a rectangular shape in front view. A first side S61, which is the upper side of the rectangular casing 60, and a second side S62, which is the lower side of the rectangular casing 60, extend in the horizontal direction. A third side S63, which is the left side of the rectangular casing 60, and a fourth side S64, which is the right side of the rectangular casing 60, extend in the vertical direction (up-down direction). The first side S61 and the second side S62 are parallel to each other. The third side S63 and the fourth side S64 are parallel to each other. When the height dimension H, which is the distance between the first side S61 and the second side S62 (first distance) and a width dimension W, which is the distance between the third side S63 and the fourth side S64 (second distance) are compared, the height dimension H is smaller than the width dimension W in the air conditioning unit 12A. Specifically, the height dimension H is 455 mm, and the width dimension W is 555 mm.

Further, the smaller one of the height dimension H and the width dimension W of the rectangular shape in front view of the casing 60, that is, the height dimension H is reduced to equal to or smaller than 2.5 times the diameter D of the air passage FS1 described above. Such design of the casing 60 makes it possible to obtain an effect relating to a blow distance of blown-out air when the two air conditioning units 12A, 12B are arranged as described later.

As described later, the smaller one of the height dimension H and the width dimension W of the casing 60 may be reduced to equal to or smaller than 2 times the diameter of the air passage FS1 by devising the arrangement of the components inside the casing 60. In the air conditioning unit 12A according to one or more embodiments, the diameter D of the air passage FS1, that is, the inner diameter ID of the first and second air passage forming members 71, 72 is 320 mm. Thus, the height dimension H (455 mm) of the casing 60 falls within a dimension equal to or smaller than 1.5 times the diameter (320 mm) of the air passage FS1.

As described above, in the air conditioning unit 12A according to one or more embodiments, the ratio of the height dimension H of the casing 60 to the diameter D of the air passage FS1 is an extremely small value which is smaller than ever before.

(5) Blow Distance of Blown-Out Air Flow when a Plurality of Air Conditioning Units are Closely Arranged

FIGS. 5 and 6 illustrate a state in which the two air conditioning units 12A, 12B are arranged in a vertical direction D1. As described above, the air conditioning unit 12A and the air conditioning unit 12B have completely the same structure. The air conditioning unit 12A is disposed directly above the air conditioning unit 12B. A clearance having a height of 85 mm is left between the air conditioning unit 12A and the air conditioning unit 12B. A support member 81 is disposed in the clearance. Each support member 81 supports the first air conditioning unit 12A or the second air conditioning unit 12B. One end of the support member 81 is fixed to a pillar 80. A height dimension L1 of the support member 81 is 80 mm. The support member 81 is selected such that a relationship of the height dimension L1 of the support member 81<(the diameter of the air passage FS1)×0.5 is satisfied between the height dimension L1 (80 mm) of the support member 81 and the diameter (320 mm) of the air passage FS1 of each of the air conditioning units 12A, 12B. In one or more embodiments, two support members 81 are disposed for each of the air conditioning units 12A, 12B, and the height dimension L1 of the support member 81 is 80 mm due to enough strength.

As illustrated in FIG. 6, when the two air conditioning units 12A, 12B are vertically arranged, and the height of the clearance between the air conditioning units 12A, 12B is set to 85 mm, a center C1 of the first air passage FS1, which is the air passage of the first air conditioning unit 12A, and a center C2 of a second air passage FS2, which is the air passage of the second air conditioning unit 12B, are separated from each other by a third distance L3 in the vertical direction D1. Further, the third distance L3 is equal to or smaller than 2.5 times the diameter (320 mm) of the cross section of each of the air passages FS1, FS2. In one or more embodiments, a relationship of the third distance L3=540 mm is satisfied, which is approximately 1.7 times the diameter (320 mm) of the cross section of each of the air passages FS1, FS2.

The effect relating to the blow distance of blown-out air (described later) can be obtained by reducing the ratio of the third distance L3 to the diameter D of the cross section of each of the air passages FS1, FS2.

(6) Blow Distance of Blown-Out Air when Two Air Conditioning Units are Arranged

Next, the blow distance of blown-out air when the two air conditioning units 12A, 12B are vertically arranged will be described with reference to FIGS. 7 to 13. Here, a result of an air flow analysis and a result of a measurement using an actual unit are comparatively verified, and findings relating to the blow distance of blown-out air are obtained using an air flow analysis model obtained by the comparative verification. Hereinbelow, the findings will be described.

(6-1) Adjustment of Air Flow Analysis Parameter Based on Air Velocity Measurement Result

First, the two air conditioning units 12A, 12B were vertically stacked, that is, the two air conditioning units 12A, 12B were arranged with no clearance therebetween, and the air velocity was measured at 1120 points using an air velocity measurement device. The number of revolutions of the fan is 1646 per minute, and the airflow volume is approximately 18 m³per minute. Further, a similar air velocity measurement was performed using only single air conditioning unit 12A.

Next, the same number of revolutions of the fan and the same airflow volume were input, and an air flow analysis was performed for the single air conditioning unit 12A (refer to FIG. 7) to acquire a time-average flow state (an air velocity distribution, a turbulent flow energy) of one revolution of the fan on the blow-out surface (refer to FIG. 8). The acquired flow state was input to a blow-out boundary surface, and another air flow analysis was performed (refer to FIG. 9). This air flow analysis was also performed for each of the case where one air conditioning unit is used and the case where two air conditioning units are vertically stacked in a manner similar to the experiment using the air velocity measurement device.

Then, the air velocity at each point obtained from the air flow analysis and a measurement result of the experiment using the air velocity measurement device were comparatively verified, and parameter adjustment of the air flow analysis was performed.

(6-2) Relationship Between Relative Distance Between Two Air Conditioning Units and Blow Distance of Blown-Out Air

Next, the air flow analysis was repeatedly performed with changed clearance dimensions between the two air conditioning units 12A, 12B which are vertically arranged. An example thereof will be illustrated in FIGS. 10 to 12.

FIG. 10 illustrates an analysis result in a case where the two air conditioning units 12A, 12B which are largely separated from each other with a clearance dimension of 2 m are operated. In the case where the clearance dimension is 2 m, the third distance L3, which is the distance between the center C1 of the first air passage FS1 and the center C2 of the second air passage FS2, is 2455 mm, and a value obtained by dividing the third distance L3 by the diameter (320 mm) of the air passages FS1, FS2 is 7.7. In this example, as with the case where one air conditioning unit is operated alone, an area having an air velocity of 1 m/s or higher is limited up to a point 4 m away from each of the air conditioning units 12A, 12B. In other words, air having an air velocity of 1 m/s reaches the point 4 m away from each of the air conditioning units 12A, 12B, but air in an area farther than the point has an air velocity lower than 1 m/s. In one or more embodiments, the distance of 4 m is referred to as the blow distance of blown-out air having an air velocity of 1 m/s.

FIG. 11 illustrates an analysis result in a case where the two air conditioning units 12A, 12B which are closely disposed with a clearance dimension of 500 mm are operated. In the case where the clearance dimension is 500 mm, the third distance L3, which is the distance between the center C1 of the first air passage FS1 and the center C2 of the second air passage FS2, is 955 mm, and a value obtained by dividing the third distance L3 by the diameter (320 mm) of the air passages FS1, FS2 is 3.0. In this example, the blow distance of blown-out air having an air velocity of 1 m/s extends to 6.7 m.

FIG. 12 illustrates an analysis result in a case where the two air conditioning units 12A, 12B which are adjacently disposed with a clearance dimension of 0 mm are operated. In the case where the clearance dimension is 0 mm, the third distance L3, which is the distance between the center C1 of the first air passage FS1 and the center C2 of the second air passage FS2, is 455 mm, and a value obtained by dividing the third distance L3 by the diameter (320 mm) of the air passages is 1.4. In this example, the blow distance of blown-out air having an air velocity of 1 m/s extends to 7.3 m.

As a result of repetitive analyses with changed parameters such as the clearance dimension in addition to the conditions illustrated in FIGS. 10 to 12, a graph of FIG. 13 relating to the blow distance of blown-out air having an air velocity of 1 m/s was obtained. As illustrated in FIG. 13, the arrangement in which the two air conditioning units 12A, 12B are not largely separated from each other so as to reduce as small as possible the value obtained by dividing the third distance L3 by the diameter D of the air passages FS1, FS2 results in the extension of the blow distance of blown-out air having an air velocity of 1 m/s. Further, FIG. 13 shows that setting the third distance L3 equal to or smaller than 2.5 times the diameter D of the air passages FS1, FS2, or equal to or smaller than 2.0 times the diameter D enables sufficient extension of the blow distance of blown-out air having an air velocity of 1 m/s.

In order to set the value (L3/D) obtained by dividing the third distance L3 by the diameter D of the air passages FS1, FS2 equal to or smaller than 2.5, even when the two air conditioning units 12A, 12B are vertically arranged with no clearance therebetween, it is necessary to satisfy a formula: the height dimension H of the casing 60<(the diameter of the air passage FS1)×2.5. This is because a relationship of the third distance=the height dimension H of the casing 60 is satisfied when the air conditioning units 12A, 12B are vertically arranged with no clearance therebetween. Conversely, in the case of an air conditioning unit in which a relationship of the height dimension H of the casing 60>(the diameter of the air passage FS1)×2.5 is satisfied, even when two air conditioning units are vertically arranged with no clearance therebetween, the upper air passage and the lower air passage are largely separated from each other, and the blow distance of blown-out air having an air velocity of 1 m/s cannot be sufficiently extended.

(7) Characteristics of Air Conditioning Unit and Air Conditioning System

(7-1)

The air conditioning unit 12A is designed such that the ratio of the smaller one of the height dimension H and the width dimension W of the casing 60 in front view (in one or more embodiments, the height dimension H) to the diameter D of the cross section of the air passage FS1 is smaller than a conventional ratio. Specifically, the height dimension H is reduced to a short dimension equal to or smaller than 2.5 times the diameter D of the cross section of the air passage FS1. Thus, when the two air conditioning units 12A, 12B are arranged in the vertical direction D1, the distance in front view between the first air passage FS1 of the first air conditioning unit 12A and the second air passage FS2 of the second air conditioning unit 12B which are adjacent to each other is reduced (refer to FIG. 6). Accordingly, air blown out through the air passage FS1 and air blown out through the air passage FS2 both play a role for reducing air flow resistance each other, and can reach far (refer to FIG. 12).

(7-2)

In the air conditioning unit 12A, the casing 60 having the height dimension H smaller than the width dimension W is used, and the thin drain pan 59 is disposed in the lower part inside the casing 60 as illustrated in FIG. 2. In addition, the use-side fan 55 and the inner diameter ID of the first and second air passage forming members 71, 72 are designed to be large to the extent possible, and the arrangement of the use-side heat exchanger 50 and the electric component box is devised such that the diameter D of the cross section of the air passage FS1 becomes large to the extent possible with respect to the height dimension H of the casing 60.

Accordingly, even the air conditioning unit 12A provided with the drain pan 59 can obtain the effect of sufficiently extending the blow distance of blown-out air having an air velocity of 1 m/s described above.

(7-3)

As illustrated in FIG. 6, in the air conditioning system 10, the two air conditioning units 12A, 12B are arranged in the vertical direction D1 with a possibly small clearance therebetween. That is, the air conditioning system 10 employs the structure in which the two air conditioning units 12A, 12B are not largely separated from each other with the arrangement space for the support member 81 secured. Specifically, the two air conditioning units 12A, 12B are vertically arranged with a clearance having a height of 85 mm therebetween.

Thus, the third distance L3, which is the distance between the center C1 of the first air passage FS1 of the first air conditioning unit 12A and the center C2 of the second air passage FS2 of the second air conditioning unit 12B, is equal to or smaller than 2.5 times the diameter D (320 mm) of the cross section of each of the air passages FS1, FS2.

As illustrated in FIG. 6, the diameter D of the first air passage FS1 and the second air passage FS2 is increased and the clearance between the two air conditioning units 12A, 12B is reduced such that the relationship of the third distance (the distance between the air passages) L3/the air passage diameter D=1.7 is satisfied. Thus, as illustrated in FIG. 13, the air conditioning system 10 can extend the blow distance of blown-out air having an air velocity of 1 m/s to 7 m or more.

(8) Modifications

(8-1)

FIGS. 5 and 6 illustrate the example in which the two air conditioning units 12A, 12B are arranged in the vertical direction D1. Alternatively, in the air conditioning system 10, three or more air conditioning units 12A, 12B, . . . may be arranged. For example, as illustrated in FIG. 14, when four air conditioning units 12A, 12B, . . . are vertically closely arranged, the blow distance of blown-out air having an air velocity of 1 m/s is further extended.

(8-2)

In the above air conditioning system 10, the air conditioning units 12A, 12B . . . each having the height dimension H smaller than the width dimension W are vertically arranged. Alternatively, the relationship between the height dimension H and the width dimension W may be reversed. Specifically, the height dimension of each air conditioning unit may be set larger than the width dimension thereof, and a plurality of air conditioning units may be arranged in the right-left direction. Also in this case, blown-out air can be caused to reach far by satisfying a relationship of the width dimension of the casing<(the diameter of the air passage)×2.5, and reducing the distance between the air passages of the air conditioning units arranged right and left.

(8-3)

Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.

REFERENCE SIGNS LIST

10 Air conditioning system

12A First air conditioning unit

12B Second air conditioning unit

55 Use-side fan

59 Drain pan

60 Casing

72 Air passage forming member

81 Support member

S61 First side

S62 Second side

S63 Third side

S64 Fourth side

H Height dimension of casing (first distance)

W Width dimension of casing (second distance)

D Diameter of cross section of air passage

FS1 First air passage

FS2 Second air passage

C1 Center of first air passage

C2 Center of second air passage

D1 Vertical direction (first direction)

L1 Height dimension of support member

L3 Distance between centers of air passages of first air conditioning unit and second air conditioning unit vertically arranged (third distance)

PATENT LITERATURE

Patent Literature 1: JP 2017-146011 A

AIR CONDITIONING UNIT AND AIR CONDITIONING SYSTEM

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CPC

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