Air conditioning device and casing structure

Abstract

To provide an air conditioning device and a casing structure. [Solution] The air conditioner of the present invention comprises a heat exchanger, a fan unit, a refrigerant that exchanges heat with the heat exchanger, and a casing that houses at least the heat exchanger and the fan unit. The air conditioner further comprises a fan unit having a propeller fan that rotates in a forward direction and a reverse direction depending on an operation mode of the air conditioner; and a fan motor for rotating the propeller fan in the forward rotation and the reverse rotation to achieve a counterflow heat exchange state regardless of the operation mode, the propeller fan having fan blades having a symmetrical shape with respect to an axis of symmetry passing through the center of the propeller fan, and the forward rotation generates an air flow in a direction from the heat exchanger to the fan unit, and the reverse rotation generates another air flow from the fan unit to the heat exchanger depending on the operation mode of the air conditioner. The air conditioner further comprises a wind guide and a crosspiece on the side for eliminating short cycling and improving air flow performance, respectively.

Description

[Technical field]

[0001] The present invention relates generally to air conditioning technology, and more specifically to a casing structure that improves the performance of air conditioners and air conditioners. [Background technology]

[0002] In order to reduce the global warming potential, the use of non-azeotropic refrigerants that can achieve extremely low global warming potential (hereinafter referred to as GWP) instead of refrigerants such as R32 is being considered. However, compared to R32, the large temperature gradient and high specific volume of non-azeotropic refrigerants will reduce the cooling / heating capacity and efficiency.

[0003] When the heat exchanger of the outdoor unit (hereinafter referred to as ODU) is operated in a conventional constant air flow direction in the cooling and heating modes, the refrigerant flow direction is reversed in the heating mode, and a parallel flow heat exchange state occurs in the heating mode. In this respect, the efficiency of the non-azeotropic refrigerant may be further deteriorated due to the generation of a parallel flow state in the heat exchange operation.

[0004] Figure 28 shows a simplified refrigerant flow direction to illustrate the countercurrent and parallel currents that occur within the heat exchangers of an ODU in heating mode, where cooler refrigerants are shown as light grey lines and warmer refrigerants are shown as dark grey (black) lines.

[0005] 28(a) and 28(b) show the operation of the outdoor heat exchanger in counterflow and parallel flow configurations, respectively, in heating mode. The heat exchanger 2802 exchanges heat between airflow 2801 drawn into the ODU (not shown) and refrigerant 2804 flowing through the tubes of the heat exchanger 2802.

[0006] In Fig. 28(a), air flow 2801 drawn into heat exchanger 2802 exchanges heat with refrigerant flow 2804 in countercurrent flow, where air flow 2801 first exchanges heat with high-temperature refrigerant. As is well known in the art, the greater the temperature difference, the higher the heat exchange efficiency, so the heat exchange between air flow 2801 and the refrigerant is more efficient.

[0007] This situation changes in the countercurrent flow shown in Figure 28(b), where the refrigerant flow direction is reversed and the airflow drawn into the ODU (not shown) first exchanges heat with the cooler refrigerant 2804, resulting in a lower heat exchange efficiency. This may be acceptable, though not optimal, for a heat exchange scheme where the refrigerant is mono- or azeotropic (or near-azeotropic). However, when the refrigerant is non-azeotropic, the air conditioning efficiency of the air conditioner is significantly reduced due to the co-current flow, its temperature gradient, and its high specific volume.

[0008] While it is possible to maintain a counter-current arrangement between the refrigerant flow and the air flow during both heating and cooling modes using non-azeotropic refrigerants, such design efforts may require major structural modifications to the air conditioning design and would be costly.

[0009] Since cooling air for the heat exchangers in the ODU is normally provided by a propeller fan, reversing the propeller fan in heating mode would provide a reversed air flow, thus providing a counterflow heat exchange scheme as shown in Figure 28(a).

[0010] However, such reversal of the propeller fan may increase the power consumption of the propeller fan in addition to degrading the airflow characteristics because a conventional propeller fan typically has a concave surface 2902 facing in the direction of rotation and a convex surface 2901 facing against the direction of rotation, as shown in Figure 29(a). Conventional propeller fans for air conditioners also have sharp blade tips at the leading edge, under the assumption that the propeller fan rotates in a given direction in its normal use. Also, conventional bellmouth shapes are asymmetric in shape and have been optimally designed for unidirectional flow, as shown in Figure 29(b). This means that conventional propeller fans have not been designed for bidirectional rotation in their practical use.

[0011] In addition, such a shifting motion of the propeller fan increases the short cycling of air in the ODU when the propeller fan rotates against its assumed rotation direction, which may also degrade the heat exchange efficiency. Therefore, this short cycling should be addressed by providing a structure with permeable performance.

[0012] There have been many efforts to improve the performance of propeller fans, for example, JP 08-285397 A (Patent Document 1) describes an invention that uses a non-azeotropic mixed refrigerant to change the flow direction in an air conditioner during cooling and heating operation. The blades are made of a movable shape memory alloy, and when changing the flow direction, the camber of the blades changes to direct the airflow from the grille to the heat exchanger.

[0013] WO2021192237 (PCT / JP2020 / 014075) (Patent Document 2) discloses an airflow guide that can change the direction of air blown out from an outdoor unit. The airflow guide is attached to the outdoor unit front panel behind the grille, and the airflow guide is composed of a number of airflow guide plates for changing the direction of the discharged air.

[0014] JP 2002-229691 A (Patent Document 3) describes an airflow guide and an outdoor unit for controlling the direction of air blown out from an ODU. However, JP 2002-229691 A does not reduce short cycling, but merely changes the direction of the discharged air arbitrarily.

[0015] Therefore, there remains a need for new technology for using non-azeotropic refrigerants while improving the performance of air conditioners without requiring major design changes to the air conditioner. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Publication No. 08-285397 [Patent Document 2] WO2021192237 [Patent Document 3] JP 2002-229691 A Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention was completed in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide a novel air conditioner which is preferably used with a non-azeotropic refrigerant. [Means for solving the problem]

[0018] An air conditioner comprising a heat exchanger, a fan unit, a refrigerant that exchanges heat with the heat exchanger, and a casing that houses at least the heat exchanger and the fan unit, the air conditioner comprising: a fan unit having a propeller fan that rotates in a forward direction and a reverse direction depending on an operation mode of the air conditioner; and a fan motor for rotating the propeller fan in the forward direction and the reverse direction to achieve a counterflow heat exchange state regardless of the operation mode, the propeller fan having fan blades having a symmetrical shape with respect to an axis of symmetry passing through a center of the propeller fan, and depending on the operation mode of the air conditioner, forward rotation generates an air flow in a direction from the heat exchanger to the fan unit, and reverse rotation generates another air flow from the fan unit to the heat exchanger, the fan blades having a generally flat shape inclined toward the air flow, A fan blade passes through the center of the fan blade and perpendicular to the axis of rotation. horizontal plane The inclination angle of the flat shape with respect to the radial direction Varies with respect to the position of

[0019] According to one or more embodiments of the present invention, the refrigerant is a non-azeotropic refrigerant.

[0020] According to one or more embodiments of the present invention, the outdoor unit has three Degree A refrigerant having the above temperature gradient is used.

[0021] According to one or more embodiments of the invention, the air conditioning device further comprises a flat area facing the fan blades and extending in the direction of the air flow, and a bellmouth surrounding the propeller fan, the centres of the outer circumferential ends of the fan blades being positioned within the level of the flat area facing the fan blades.

[0022] According to one or more embodiments of the invention, the centre of the outer circumferential edge of the fan blade is shifted to the centre of the flat region of the bellmouth or from the centre of the flat region towards the heat exchanger.

[0023] According to another aspect of the present invention, there is provided an outdoor unit for an air conditioner, the casing comprising a wind guide integrally disposed on the side of the air conditioner, which allows an airflow discharged from the side to escape away from the front side of the propeller fan of the air conditioner, thereby preventing short cycling during reverse rotation of the propeller fan, the outdoor unit comprising a heat exchanger, a fan unit, and a non-azeotropic refrigerant which exchanges heat with the heat exchanger, the casing housing the heat exchanger, the outdoor unit further comprising a fan unit comprising a propeller fan which rotates in a forward and reverse direction depending on an operation mode of the air conditioner, and a fan motor which rotates the propeller fan in the forward and reverse directions to achieve a counterflow heat exchange state regardless of the operation mode, the propeller fan comprising a plurality of fan blades having shapes symmetrical with respect to an axis of symmetry passing through the center of the propeller fan, the fan blades having a generally flat shape inclined toward the airflow, A fan blade passes through the center of the fan blade and perpendicular to the axis of rotation. horizontal plane The inclination angle of the flat shape with respect to the radial direction Varies with respect to the position of

[0024] According to one or more embodiments of the invention, the wind guide has an aperture or apertures positioned away from the front side of the outdoor unit.

[0025] According to one or more embodiments of the invention, the wind guide has an aperture that is angled towards the rear side of the outdoor unit or forms an aperture that is angled towards the rear side.

[0026] According to one or more embodiments of the invention, the casing comprises a plurality of slots on the lateral side of the casing, the plurality of slots being defined by cross bars having an approximately triangular-rectangular cross section with their apexes facing towards the heat exchanger. Effect of the Invention

[0027] According to the present invention, an air conditioning device and casing structure can be provided that can be used suitably with non-azeotropic refrigerants, and that can provide good forward and reverse airflow, acceptable static pressure rise, efficiency and noise suppression. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 generally illustrates an exemplary embodiment of an air conditioning device 100 in accordance with one embodiment of the present invention. [Diagram 2] FIG. 2 shows a detailed structure of an ODU 101 according to one embodiment of the invention. [Diagram 3] FIG. 3 shows a partial cross-sectional view of ODU 101 through line AA in FIG. [Figure 4] FIG. 4 illustrates an exemplary conventional propeller fan 400 along with the novel structure of the propeller fan 102 of one embodiment of the present invention. [Diagram 5] FIG. 5 shows a detailed side view of propeller fan 102 according to one embodiment of the invention. [Figure 6] FIG. 6 illustrates an alternative embodiment in which the location of propeller fan 102, i.e., fan blades 102-1, 102-2, and 102-3, has been shifted to HEX 125 in accordance with one or more embodiments of the present invention. [Figure 7] FIG. 7 illustrates, in tabular form, air conditioning performance according to one or more embodiments of the present invention. [Figure 8] FIG. 8 illustrates, in tabular form, air conditioning performance according to one or more embodiments of the present invention. [Figure 9] FIG. 9 illustrates, in tabular form, air conditioning performance according to one or more embodiments of the present invention. [Figure 10A] FIG. 10A shows a plot of the results of a cycle simulation of an air conditioner in accordance with one or more embodiments of the present invention in heating mode. [Figure 10B]FIG. 10B shows the simulated APF values ​​for the examples and comparative examples, as well as the parameters in the simulation and the simulated APF values. [Figure 11] FIG. 11 shows the results of a CFD (Computational Fluid Dynamics) calculation of the airflow around ODU101A (equipped with a conventional propeller fan 400) and ODU101 (equipped with the propeller fan 102 of the present invention) in counter-rotating operation in accordance with one or more embodiments of the present invention. [Figure 12] FIG. 12 shows one embodiment of a wind guide 1201 and an ODU 101 with the wind guide 1201 attached. [Figure 13] FIG. 13 shows a CFD simulation illustrating the effect of one embodiment wind guide 1201 in accordance with the present invention. [Figure 14] FIG. 14 illustrates another embodiment of a wind guide 1401 according to one or more embodiments of the present invention. [Figure 15] FIG. 15 shows a CFD simulation illustrating the effect of the wind guide 1401 of FIG. [Figure 16] FIG. 16 illustrates another embodiment of a wind guide 1601 according to one or more embodiments of the present invention. [Figure 17] FIG. 17 shows a CFD simulation illustrating the effect of the wind guide of FIG. [Figure 18] FIG. 18 illustrates another embodiment of a wind guide 1801 according to one or more embodiments of the present invention. [Figure 19] FIG. 19 shows a CFD simulation illustrating the effect of the wind guide 1801 of FIG. [Figure 20] FIG. 20 illustrates another embodiment of a wind guide 2001 according to one or more embodiments of the present invention. [Figure 21] FIG. 21 shows a CFD simulation illustrating the effect of the wind guide 2001 of FIG. [Figure 22A]FIG. 22A illustrates another embodiment for improving the performance of one or more embodiments of the present invention. [Figure 22B] FIG. 22B shows an enlarged view of the rungs 2203 that form the transverse slots of the casing. [Figure 23] FIG. 23 illustrates the effect of rung shape on the airflow performance of one or more embodiments of the present invention. [Figure 24] FIG. 24 shows a CFD calculation of the effect of lance shape on velocity distribution in one or more embodiments of the present invention. [Diagram 25] FIG. 25 shows a CFD calculation of the effect of lance shape on velocity distribution in one or more embodiments of the present invention. [Figure 26] FIG. 26 shows a CFD calculation of the effect of lance shape on velocity distribution in one or more embodiments of the present invention. [Figure 27] FIG. 27 shows a CFD calculation of the effect of lance shape on velocity distribution in one or more embodiments of the present invention. [Figure 28] FIG. 28 illustrates exemplary countercurrent and cocurrent refrigerant flow directions occurring during heating mode in the heat exchange of an ODU. [Figure 29] FIG. 29 shows the shape of a conventional propeller fan and the assumed positioning between the fan blades and the bellmouth. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] General configuration of air conditioning device One or more embodiments will now be described with reference to the drawings, which should be used only to understand the present invention. The drawings and the detailed description below should not be understood to be limiting the present invention recited in the appended claims in any way. In the description of the drawings, it should be understood that well-known elements and relatively minor elements are not described in the drawings for clarity of explanation in addition to the essential understanding of the present invention. However, the omission of such elements in the description does not mean that such elements are not used in the present invention. Hereinafter, similar elements are referred to by similar numbers and symbols unless otherwise stated.

[0030] 1 generally illustrates an exemplary embodiment of an air conditioner 100 in accordance with one or more embodiments of the present invention. The type of air conditioner 100 of one or more embodiments is not particularly limited and may be implemented as a packaged air conditioner (PAC), a room air conditioner (RAC), a multi-air conditioner such as a variable refrigerant flow (VRF) system, or a chiller depending on the particular application.

[0031] The air conditioning device 100 includes an indoor unit (IDU) 110, an outdoor unit (hereinafter referred to as ODU) 101, and refrigerant piping 140 connecting the indoor unit 110 and the ODU 101. The indoor unit 110 is disposed in an indoor space, where air conditioning is performed, to provide air conditioning desired by a user through a remote control terminal such as a remote controller 130 operated by the user.

[0032] The indoor unit 110 houses a filter 113, a fan 114, and an indoor heat exchanger (not shown), and is arranged from the top to the front with an intake grill 112 facing the indoor space. The indoor unit 110 supplies air for air conditioning to the indoor space from an exhaust grill 115, and draws indoor air into the indoor unit 110 through the intake grill 112 to enable air conditioning of the indoor air.

[0033] Additionally, ODU 101 houses within casing 108 at least a compressor 126, a heat exchanger (HEX) 125, and a fan unit including a propeller fan 102 and a fan motor (not shown). Propeller fan 102 comprises a hub 103 and a number of fan blades 102-1, 102-2, 102-3 extending radially outward from hub 103; however, the number of blades on the propeller fan is not limited to three, and other numbers of blades may be permitted by one or more embodiments of the present invention.

[0034] The compressor 126 compresses the refrigerant returned from the indoor unit 110 after conditioning the indoor air, and sends it to the heat exchanger 125 to adjust the thermodynamic state of the refrigerant, so as to provide continuous air conditioning in the cooling mode. The compressor 126 compresses the refrigerant returned from the outdoor heat exchanger 125, and sends it to the indoor unit 110 to adjust the thermodynamic state of the refrigerant, so as to provide continuous air conditioning in the heating mode. The propeller fan 102 is driven by a fan motor (not shown), and in forward rotation for the cooling mode, draws outdoor air into the ODU 101 from the side slots and the side openings on the rear side. The propeller fan 102 is driven by a fan motor (not shown), and in reverse rotation for the heating mode, draws outdoor air into the ODU 101 from the grill structure 107 attached to the front side of the ODU. In this way, the present invention provides a constant counterflow state with respect to the HEX 125 and the refrigerant, regardless of the operation mode.

[0035] Conventional propeller fans have been designed by optimizing efficiency for one primary direction of rotation, so if the propeller fan rotates in reverse, the propeller fan's efficiency decreases. According to the present disclosure, a novel propeller fan structure is described to achieve a "constant counterflow configuration" with respect to the direction of refrigerant flow with changes in operation mode, which can be used appropriately in both forward and reverse rotation without significant impact on air conditioning performance.

[0036] In this specification, the term "forward rotation" refers to the direction of rotation of the propeller fan that generates airflow from the rear side to the front side of the casing 108, and the term "reverse rotation" refers to the direction of rotation of the propeller fan that generates airflow from the front side to the rear side of the casing 108. In addition, the term "front side" in this specification means the opposite side beyond the fan unit on which HEX 125 is located, and refers to the side that is usually covered by the front panel. Now, the propeller fan of the present invention will be described in detail.

[0037] Propeller Fan 2 shows a detailed structure of the ODU 101 of one or more embodiments of the present invention. The ODU 101 accommodates at least the compressor 126, the HEX 125, and the propeller fan 102. The propeller fan 102 includes a hub 103 and a plurality of blades 102-1, 102-2, and 102-3 extending radially outward from the hub 103. A fan motor (hidden by the propeller fan 102 in FIG. 2 and not shown) is disposed behind the hub 103, which is in turn supported by a support member 201, so that the propeller fan 102 and the fan motor are firmly installed within the ODU 101.

[0038] The propeller fan 102 is circumferentially surrounded by a bellmouth 104, and leaves a certain distance between the outer peripheral ends of the fan blades 102-1, 102-2, and 102-3 of the propeller fan 102 and the bellmouth 104. Furthermore, a rear panel opening and a number of slots 105 are formed on the lateral sides of the casing 108 of the ODU 101 to allow outside air to flow in / out of the ODU 101 for heat exchange with the HEX 125 during forward / reverse rotation.

[0039] FIG. 3 shows a partial cross-sectional view of the ODU 101 through the line AA in FIG. 2, which further shows the structural details around the propeller fan 102. The ODU 101 includes a HEX 125 disposed along the rear wall of the casing 108 of the ODU 101. The HEX 125 exchanges heat between the airflow from the outside environment and the refrigerant to achieve the desired air conditioning. When used with a non-azeotropic refrigerant, the flow direction of the airflows 203, 204 from the surrounding environment changes as shown in FIG. 3 for heating and cooling modes, respectively.

[0040] The propeller fan 102 is positioned and supported by a support member 201 that extends from the top panel to the bottom panel of the casing 108 of the ODU 101. The fan blades 102-1, 102-2, and 102-3 of the propeller fan 102 extend radially outward from the outer surface of the hub 103 close to the bellmouth 104 and leave a certain distance to the bellmouth 104. In one or more embodiments shown in FIG. 3, the center of the outer circumferential end of the fan blade, for example the fan blade 102-1, is positioned approximately at the vertical center of the bellmouth 104 along the direction of air flow. This configuration is not essential and may be changed in consideration of the efficiency of the air conditioner, such as air flow rate or power consumption, or both. Details of the positioning between the bellmouth 104 and the propeller fan 102 / fan blades 102-1, 102-2, and 102-3 will be described later.

[0041] For non-azeotropic refrigerants with low GWP, such as R454A, R454C, and a mixture of 50% R32 and 50% R1234yf, the temperature gradient is relatively large, and countercurrent use is highly recommended. In this disclosure, the term "temperature gradient" refers to the difference in the start and end temperatures between evaporation and condensation in a heat exchanger (HEX) due to the composition difference between the liquid and gas phases.

[0042] If the air flow to the HEX 125 were to be co-current with respect to the refrigerant flow within the HEX 125, the heat exchange efficiency of the HEX 125 would decrease, and this could even negate the benefit of using a non-azeotropic refrigerant. This fact raises the need to provide a "constant counter-flow configuration" between the refrigerant flow within the HEX 125 and the air flow from the external environment.

[0043] Further, in this disclosure, the term "co-current" means that the airflow from the ambient environment first contacts the cooler refrigerant flowing through HEX 125 for heating mode. Alternatively, the term "counter-current" means that the airflow from the ambient environment first contacts the warmer refrigerant flowing through HEX 125 for heating mode. Further, the term "always counter-current" means that the airflow from the ambient environment first contacts the warmer refrigerant flow for heating mode and the cooler refrigerant for cooling mode.

[0044] The ODU 101 of one or more embodiments of the present invention can address the above needs by using a novel propeller fan 102 having a symmetrical structure. The propeller fan 102 and fan blades 102-1, 102-2, 102-3 of the present invention will now be described in detail.

[0045] The propeller fan 102 of one or more embodiments of the present invention can change the direction of the airflow by changing the direction of rotation of the propeller fan 102. As shown in Figure 3, airflow 204 (see Figure 3) is in the forward direction with respect to the HEX 125, and airflow 203 (see Figure 3) is in the reverse direction with respect to heat exchange with the HEX 125.

[0046] A conventional propeller fan (described below with reference to FIG. 4) has a concave surface facing in the direction of rotation and a convex surface facing backward in the direction of rotation, as well as a sharp blade tip at the leading edge, which suppresses noise.

[0047] As shown in FIG. 3, for example, fan blades 102-1, 102-2, and 102-3 in one or more embodiments of the present invention are fixed to hub 103 at an inclined angle along the direction of airflow, and the rotation of propeller fan 102 generates airflow 203 and airflow 204 depending on its direction of rotation.

[0048] Figure 4 shows the novel structure of fan blade 102 according to one or more embodiments of the present invention, along with a sample conventional propeller fan 400. Figure 4(a) shows a plan view of propeller fan 102 according to one or more embodiments of the present invention, and Figure 4(b) shows a plan view of conventional propeller fan 400.

[0049] Each of the fan blades 102-1, 102-2, and 102-3 has linear symmetry about an imaginary line of symmetry B that extends from the center of the propeller fan 102 to the circumferential center of each of the fan blades 102-1, 102-2, and 102-3, but is shown on the fan blade 102-2 for illustrative purposes. The other fan blades 102-1 and 102-3 also have the same structure.

[0050] In reverse rotation of a conventional fan, the camber reverses, the flow no longer attaches to the blade surface, and airflow is dramatically reduced due to flow separation.

[0051] 5 shows a detailed side view of the propeller fan 102 (FIG. 5(a)), a circumferential blade cross section at a diameter (FIG. 5(b)), and the relative positioning between the propeller fan 102 and the bellmouth 104 (FIG. 5(c)). Fan blade 102-2 is best illustrated to show its side structure, but the other fan blades 102-1, 102-3 each have a similar shape and configuration.

[0052] In particular, Figure 5(c) shows detailed relative positioning between the fan blade 102-2 and the bellmouth 104. In one embodiment, the circumferential center of the outer peripheral edge 102f of the fan blade 102-2 can be positioned approximately at the center of the bellmouth 104 along the airflow direction with the outer peripheral edge 102f closest to the bellmouth 104 as shown in Figure 5(c). In an alternative embodiment, the outer peripheral edge 102f of the fan blade 102-2 can be shifted from the center of the bellmouth 104 towards the HEX 125.

[0053] The bellmouth 104 has a generally rectangular cross section with rounded corners to form a flat region and a number of near-circular regions. The flat region faces the fan blades 102-1, 102-2, and 102-3 and extends in the direction of the airflow while surrounding the propeller fan 102. The bellmouth 104 straightens the airflow passing through the ODU 101.

[0054] The direction and amount of shifting can be varied depending on the specific requirements and the shape of the fan blades 102-1, 102-2, 102-3. In one exemplary embodiment, when the propeller fan 102, i.e., the fan blades 102-1, 102-2, and 102-3, are shifted toward the HEX 125, the air blowing performance and shaft power can be preferably improved as described below. Again, it is pointed out that the relative positions between the fan blades 102-1, 102-2, and 102-3 and the bellmouth 104 illustrate one example for better understanding the principles of the present invention, and the present invention is not limited and / or exhausted to the disclosed embodiment.

[0055] 6 illustrates an alternative embodiment to the above, in which the propeller fan 102, i.e., fan blades 102-1, 102-2, and 102-3, are shifted toward the HEX 125. In the exemplary embodiment in FIG. 6, the outer circumferential edge 102f of the fan blade 102-1 is positioned approximately 10 mm inward relative to the center of the bellmouth 104. In yet another embodiment, the propeller fan 102 can be positioned approximately 20 mm inward relative to the center of the bellmouth 104.

[0056] Now, with reference to FIGS. 7-10, embodiments of the present invention and their practical effects are illustrated by using simulation results.

[0057] The inventors constructed the ODU 101 shown in Figure 2 and measured some of its performance under several conditions. As a comparative example, another ODU was used that includes a similar configuration except that it was fitted with a conventional fan blade such as the propeller fan 400. The following table lists the conditions of the simulation.

[0058] [Table 1] 1) The propeller fan 102 has the configuration shown in FIG. 2) It has a configuration similar to that of propeller fan 400 in FIG. 3) The amount of inward shift (HEX125) in millimeters (mm) from the normal position. 4) The dimension of the shroud position from the front panel is (mm).

[0059] Figure 7 shows the simulation results under one RPM as a table, which are summarized as follows: 1) At the same RPM, the airflow of the conventional ODU drops dramatically by 14.1% in reverse rotation and the shaft power drops by 12.2% compared to those when operating in forward rotation. 2) At the same RPM, Examples 1-4 showed no significant decrease or change or both in air flow rate and reverse rotation for Examples 1-2 and only a slight decrease for Examples 3-4. With regard to forward and reverse rotation, in comparison with the comparative example, with regard to shaft power, Examples 1 to 4 show an increase in shaft power. 3) At the same RPM, the airflow of Examples 1-4 is maintained within a 10% range, with Example 3 in particular showing the best performance in both airflow and shaft power. 4) In forward rotation at the same RPM, the airflow in Example 3 increases by 5% and the shaft power increases by 16.4% compared to the comparative example, as listed as the best result in the last column of the table shown in Figure 7. In reverse rotation, the airflow in Example 3 increases by 21.2% and the shaft power increases by 31.5% compared to the comparative example, as shown in the last column of the table in Figure 7.

[0060] The last row of the table in Figure 7 lists the change in shaft power when the RPM of the propeller fan 102 is kept constant in forward and reverse rotation. As shown in Figure 7, all the examples show relatively low change between reverse rotation compared to the comparative examples. In particular, Example 3 (propeller fan 102 positioned 10 mm inward) shows excellent results with a 0.9% drop in airflow and a 0.7% drop in shaft power between forward and reverse rotation compared to its forward rotation, as shown in Figure 7.

[0061] Since the propeller fan 102 according to one or more embodiments of the present invention tends to increase the air flow rate when compared with a conventional propeller fan at the same rotation speed, the inventors further tested the performance of the ODU 101 equipped with the propeller fan 102 according to one or more embodiments and the comparative example at 3553 CMH (cubic meters per hour) to test the performance change at the same air flow. The results are shown in the table in FIG. 8.

[0062] As shown in FIG. 8, the ODU101 according to the present invention shows excellent low change in shaft power compared to the shaft power of the comparative example in forward rotation for both forward and reverse rotation, but the comparative example increases shaft power by 38.7% in reverse rotation to maintain the air flow rate at 3553 CMH compared to its shaft power in forward rotation.

[0063] In particular, the shaft power of Example 3 is maintained within 2.5% in reverse rotation with the same airflow, meaning that the shaft power of Example 3 is maintained substantially constant regardless of the direction of rotation of the propeller fan 102 at the same airflow rate. Thus, using a propeller fan according to one or more embodiments of the present invention and using a non-azeotropic refrigerant, target performance requirements for suppressing performance changes between forward and reverse rotation can be met.

[0064] As discussed above, it is concluded that the ODU 101 according to one or more embodiments of the present invention, such as the propeller fan 102 equipped with the fan blades 102-1, 102-2, and 102-3, can provide a counterflow to the heat exchanger (HEX) 125 without significant degradation in air conditioner performance, such as air flow rate and shaft power. Thus, the efficiency of the air conditioner 100 using a non-azeotropic refrigerant can be significantly improved by the present invention and also contribute to reducing global warming.

[0065] Based on the above findings, the inventors further tested the performance in terms of shaft power and rotation speed (RPM) under the same air flow rate of 3553 CMH. The results are shown in a table in FIG. 9. As shown in FIG. 9, it is found that the decrease in rotation speed in RPM is 4.8% and 3.9% in both forward and reverse rotation in Example 3, respectively, while the shaft power remains substantially the same as that of the conventional ODU. This means that the relative positioning of the fan blades 102-1, 102-2, and 102-3 has importance in the performance of the fan blades 102-1, 102-2, and 102-3 of one or more embodiments of the present invention.

[0066] From the results shown in Figure 9, it can be seen that ODU 101, i.e., a fan unit equipped with propeller fan 102 / fan blades 102-1, 102-2, and 102-3, can excellently suppress performance changes between forward and reverse rotation while maintaining requirements such as air flow rate and shaft power without any significant disadvantage compared to conventional ODUs.

[0067] 10A shows a graph of the results of a cycle simulation of the air conditioner 100 in a heating mode according to one or more embodiments of the present invention by assuming that the ODU 101 is equipped with a fan unit including the propeller fan 102 of one embodiment of the present invention. The cycle simulation during the heating mode shows improving APF (Annual Performance Factor) values ​​with non-azeotropic refrigerants such as R454B, 50% R32 and 50% R1234yf, R454A and R454C.

[0068] The APF value gradually increases as the temperature gradient increases up to 5K, and the APF level gradually starts to decrease after the temperature gradient of 5K, which means that the present invention can provide a larger margin for the temperature gradient of non-azeotropic refrigerants, so that the present invention can realize the use of a wide variety of non-azeotropic refrigerants while improving the APF value. Figure 10B shows the parameters in the simulation and the simulated APF values ​​for the examples and comparative examples, as well as the simulated APF values. As shown in Figure 10B, the conventional propeller fan reduces the APF value by reverse rotation, but the propeller fan of the present embodiment improves the APF value.

[0069] Casing Structure Although the configuration of ODU101 has been described so far, air conditioning performance may also be improved by adjusting the airflow characteristics around ODU101. Figure 11 shows the results of a CFD (Computational Fluid Dynamics) calculation of the airflow around ODU101A (equipped with a conventional propeller fan) and ODU101 (equipped with the propeller fan 102 of the present invention) in reverse rotation operation. In Figures 11, 13, 15, 17, 19 and 21, the airflow direction of the outdoor air sucked into ODU101, 101A is indicated by the arrow E.

[0070] Simulation 1110 shows airflow in counter-rotation operation around ODU 101A equipped with a conventional propeller fan similar to propeller fan 400. Simulation 1120 shows airflow in counter-rotation operation around ODU 101 equipped with propeller fan 102 of one embodiment of the present invention.

[0071] Additionally, the airflow emitted from the ODUs 101, 101A through the slots 105 in the sides of the casings 108 of the ODUs 101, 101A is shown by lines, the direction of which is indicated by the curved thick arrows in Figure 11. In Figures 13, 15, 17, 19 and 21, these thick arrows have been omitted for clarity of results.

[0072] Furthermore, the airflow speed is represented by a heat map, and the darker the color in each figure, the faster the speed. For clarity of the airflow direction in the figures, the outdoor air is sucked in from the front side and has a higher speed as the gray color becomes darker, and the air entering the ODU 101, 101A is discharged from the rear and side of the casing 108 of the ODU 101, 101A.

[0073] As for the ODU101A, it is equipped with a conventional propeller fan similar to the propeller fan 400, and the outdoor air is sucked into the ODU101A due to the reverse rotation of the propeller fan 400. In the reverse rotation, the sucked air flows toward the HEX 125, and after heat exchange, the air is discharged from the openings and slots 105 on the rear side of the casing 108 of the ODU101A.

[0074] The discharged airflow tends to bypass to the front side where the outdoor air is sucked into the ODU 101 due to the counter-rotating action. This movement of the airflow from the side side (through the slots 105) is referred to herein as "short cycling", and such short cycling adversely affects the air conditioning performance of both the ODUs 101, 101A.

[0075] As shown in the CFD results 1120, in an ODU 101 including a propeller fan 102 of one embodiment of the present invention, air released from the side tends to travel a shorter path around to the front panel side compared to the conventional ODU 101A, so short cycling should be suppressed more efficiently in an ODU 101 equipped with a propeller fan 102 of one or more embodiments of the present invention.

[0076] To mitigate short cycling of the discharged air, one or more embodiments may employ wind guides disposed around the sides of the ODU 101. One example of such a wind guide 1201 is shown in FIG. 12. In FIG. 12, FIG. 12(a) shows an exploded front view of the ODU 101; FIG. 12(b) shows an exploded rear view of the ODU 101; and FIG. 12(c) shows a front perspective view of the ODU 101 with the wind guide 1201 integrated into the ODU 101.

[0077] The wind guide 1201 can be attached to the side of the ODU 101 where the slot 1202 is formed by any fastener known in the art, such as snap-in hooks, bolts, screws, etc. The wind guide 1201 shown in Figure 12, and particularly Figure 12(c), comprises opposing bottom and top walls 1201a, 1201d, and a plurality of opposing lateral walls 1201b in pairs. The plurality of lateral walls 1201b are integral at their respective vertical edges with the top and bottom walls 1201a, 1201d to define a box-like shape, leaving opposing apertures 1201c, 1201f between the respective walls 1201a, 1201b and 1201d, respectively.

[0078] Each of the multiple side walls 1201b has a first sub-wall extending vertically from an edge contacting the ODU 101 and a second sub-wall extending at an angle from the first sub-wall toward the opposing side wall 1201b to form an aperture 1201c that is narrower than the opposite aperture 1201f formed adjacent to the ODU 101.

[0079] The pair of bottom and top walls 1201a, 1201d slope from the lower aperture 1201f to the upper aperture 1201c, respectively. The side walls 1201b and the pair of top and bottom walls 1201a, 1201d form a hood-like shape to allow the discharged air to be discharged away from the ODU 101 and to suppress short cycling of the discharged air over the slot 1202. This wind guide is low cost to manufacture and also simple to assemble to mount on the side of the ODU 101.

[0080] Figure 13 shows CFD simulations 1310, 1320 illustrating the effect of the wind guide 1201, where Figure 13(a) is a wide-area view 1310 around the ODU 101, and Figure 13(b) is a narrow-area view 1320 around the ODU 101. As shown in Figure 13, the short cycling of the discharged air can be effectively suppressed by installing the wind guide 1201 compared to Figure 11 (Figure 1120).

[0081] FIG. 14 illustrates another embodiment of a wind guide 1401 of one or more embodiments according to the present invention. In FIG. 14, FIG. 14(a) illustrates an exploded front view of the ODU 101; FIG. 14(b) illustrates an exploded rear view of the ODU 101; and FIG. 14(c) illustrates a front perspective view of the ODU 101 into which the wind guide 1401 is integrated. The wind guide 1401 of FIG. 14 has a shape generally similar to the wind guide 1201 shown in FIG. 12, except for the bottom and top walls 1401a, 1401d, which extend horizontally from the side of the ODU 101. This wind guide can also be manufactured at low cost and is also simple to assemble to mount on the side of the ODU 101.

[0082] Figure 15 shows the effect of the wind guide of Figure 14 as CFD simulations 1510, 1520, where Figure 15(a) is a wide-area view 1510 of the surroundings of the ODU 101 and Figure 15(b) is a narrow-area view 1520 of the surroundings of the ODU 101. As shown in Figure 15, the short cycling of the discharged air can also be effectively improved compared to the case where the wind guide is not used as in Figure 11.

[0083] Figure 16 shows another embodiment of a wind guide 1601 in accordance with one or more embodiments of the present invention. In Figure 16, Figure 16(a) shows an exploded front view of the ODU 101; Figure 16(b) shows an exploded rear view of the ODU 101; and Figure 16(c) shows a front perspective view of the ODU 101 into which the wind guide 1601 is integrated.

[0084] The wind guide 1601 of FIG. 16 also has a pair of side walls, but the first side wall 1601b closer to the front of the ODU 101 has a greater length than the second side wall 1601b and has a convex curved surface that extends smoothly from the end adjacent the ODU 101 to the upper aperture 1601c.

[0085] The second side wall 1601b opposite to the first side wall 1601b has a length shorter than that of the first side wall 1601b and extends generally perpendicularly from the end adjacent to the ODU 101. The first side wall 1601b functions as a wind guide for deflecting the airflow to the opposite side of the front surface of the ODU 101 for the discharged air, so that short cycling can be effectively improved. This wind guide can also be manufactured at low cost and is also simple in assembly to be mounted on the side of the ODU 101.

[0086] Figure 17 shows the effect of the wind guide of Figure 16 as CFD simulations 1710, 1720, where Figure 17(a) is a wide-area view 1710 of the surroundings of the ODU 101 and Figure 17(b) is a narrow-area view 1720 of the surroundings of the ODU 101. As shown in Figure 17, the short cycling of the discharged air can also be effectively improved compared to the case where no wind guide is used as in Figure 11.

[0087] Figure 18 shows another embodiment of a wind guide 1801, where Figure 18(a) shows an exploded rear view of an ODU 101; Figure 18(b) shows a rear view of the ODU 101 with the wind guide 1801 integrated; and Figure 18(c) shows a front perspective view of the ODU 101 with the wind guide 1801 integrated.

[0088] 18, in order to prevent short cycling, multiple inclined plates are formed in the wind guide 1801 on the opposite side of the front side of the ODU 101, and the openings formed between the inclined plates allow the discharged air to escape from the ODU 101 towards the rear side. The inclined plates are respectively arranged with the same pitch along the horizontal direction and also along the vertical direction to form a louver-like configuration on the side of the ODU 101 facing the rear side.

[0089] Each inclined plate is inclined at an angle of about 45° with a length of about 23 mm in one embodiment. Due to the inclination of the plate, the flow on the casing 108 discharged from the slot 1802 can be deflected toward the rear side of the ODU 101, thus improving the short cycling. Moreover, this wind guide can be manufactured at low cost and is also simple in assembly to be mounted on the side of the ODU 101.

[0090] Figure 19 shows the effect of the wind guide of Figure 18 as CFD simulations 1910, 1920, where Figure 19(a) is a wide-area view 1910 of the surroundings of the ODU 101 and Figure 19(b) is a narrow-area view 1920 of the surroundings of the ODU 101. As shown in Figure 19, the short cycling of the discharged air can also be effectively improved compared to the case where no wind guide is used as in Figure 11.

[0091] FIG. 20 shows yet another embodiment of a wind guide, where FIG. 20(a) shows an exploded front view of ODU 101; FIG. 20(b) shows a front perspective view of ODU 101 with an integrated wind guide 2001.

[0092] In this embodiment, a plurality of rectangular inclined wind guide segments facing away from the front side of the ODU101 to prevent short cycling are formed in the wind guide 2001 at positions corresponding to the slots 2001 as shown in FIG. 20. The length of each rectangular wind guide is not limited thereto and can vary to extend at an angle of 45°, about 20 mm to about 25 mm, on the side opposite to the front side of the ODU101. Due to its shape and inclination angle, short cycling can be effectively improved. This wind guide can also be manufactured at low cost and is also simple in assembly to be mounted on the side of the ODU101.

[0093] Figure 21 shows the effect of the wind guide of Figure 20 as CFD simulations 2110, 2120, where Figure 21(a) is a wide-area view 2110 of the surroundings of the ODU 101 and Figure 21(b) is a narrow-area view 2120 of the surroundings of the ODU 101. As shown in Figure 21, the short cycling of the discharged air can also be effectively improved compared to the case where the wind guide is not used as in Figure 11.

[0094] In the above-mentioned embodiments of the wind guides 1201, 1401, 1601, 1801 and 2001, the emission direction is described as being toward the rear side, however, the emission direction is not limited and can be envisaged in any direction other than toward the front side, such as upward, downward and distal.

[0095] FIG. 22A shows yet another embodiment for improving performance, where FIG. 22A(a) shows a front view of ODU101; FIG. 22A(b) shows a rear perspective view of ODU101; and FIG. 22A(c) shows an enlarged configuration of slot 2202.

[0096] To further improve the airflow performance of the ODU 101 in both forward and reverse rotation, the embodiment of FIG. 22A includes rungs to define slots 2202 formed on the casing 108, each of which has an inclined surface thereon that faces easily toward the HEX 125 as shown in FIG. 22A. This configuration provides a rung 2203 that is rectangular in cross section with its top facing inward. This inclined surface formed on the rung 2203 has a length of about 5 mm and an inclination angle of about 30° in one embodiment. The length and angle can be adjusted depending on the performance changes. Additionally, this slot shape may be used in combination with the wind guides 1201, 1401, 1601, 1801, and 2001 described above to further improve performance.

[0097] FIG. 22B shows a close-up of the rungs 2203 forming a slot in the casing. FIG. 22B(a) is an exploded rear view, and FIG. 22B(b) shows a close-up of the slot 2202 formed by the rectangular rungs 2203. Due to the shape of the rungs 2203, the velocity distribution can be improved compared to the simple slot case. FIG. 23 shows in tabular form the effect of the rung shapes on one or more airflow performances according to the present invention. Due to this configuration of the slots 2202, the airflow performance is improved as shown in FIG. 23. For example, at the same RPM, the airflow is improved by 1.2% in both forward and reverse rotation. In addition, at the same airflow rate, the shaft power is reduced by 2.7% and 2.2% in forward and reverse rotation, respectively.

[0098] Figures 24-27 show CFD simulations 2410-2720 of the velocity distribution inside the ODU 101 of the third embodiment with the rectangular shaped rung 2203 and the conventional simple rectangular shaped slot 105. All figures show the speed-up of the discharged air through the rectangular shaped rung 2203 on the side of the ODU 101, which further contributes to imparting a large velocity to the discharged air in both forward and reverse rotation. In Figures 24-27, the improved velocity areas are indicated by arrows.

[0099] The present invention has been described above with reference to the accompanying drawings. The described embodiments and drawings are provided only as examples for those skilled in the art to understand the spirit of the invention, and should not be understood as limiting the invention recited in the claims in any manner.

[0100] The terms used in this disclosure have been selected to best describe the embodiments and principles of the present invention, and are not intended to imply any limitations on the claimed invention. Terms should be understood as their positive technical meaning, dictionary meaning, or meaning commonly used by those skilled in the art to describe features or elements, or a combination thereof.

[0101] In the above disclosure, when a numerical value is described with the word "about", it should be understood as including the numerical value itself, within the range of measurement error known in the art at the time of filing the present application that can realize the technical effect of the present disclosure, or even within a range of ±5% to ±10% of the notified value. In addition, the terms "approximately" or "substantially" or combinations thereof include the range of elements or features or combinations thereof that a person skilled in the art would understand to be the elements or features or combinations thereof identified by such terms.

[0102] It is understood that those skilled in the art can understand many alternatives, modifications, or variations of the explicitly described or implied embodiments and examples or combinations thereof from the disclosure of this specification; however, such alternatives, modifications, or variations of the present invention, or their equivalents, or combinations thereof, should be within the scope of the present invention as long as such alternatives, modifications, or variations, or their equivalents, or combinations thereof exhibit the technical effects and spirit of the present invention described in this disclosure. The true scope of the present invention should be understood only from the features and elements as claimed in the appended claims. [Industrial Applicability]

[0103] In accordance with the present invention, an air conditioning system and casing structure suitable for use with non-azeotropic refrigerants is provided that can provide excellent forward and reverse flow rates, acceptable static pressure rise, efficiency and noise suppression while contributing to a solution to global warming. [Explanation of symbols]

[0104] 100-Air conditioning equipment 101-Outdoor Unit (ODU) 102-Fan unit 102-1, 102-2, 102-3 - Fan blades 103-Hub 104-Bellmouth 105-Slot 106-Wind Guide 107-Front Grill 108-Casing 125-Heat exchanger (HEX) 126-Compressor 201-Support material 202-Fan motor 203-Air flow (reverse direction) 204-Air flow (forward) 400-Conventional Propeller Fan

Claims

1. An air conditioning apparatus comprising a heat exchanger, a fan unit, a refrigerant that exchanges heat with the heat exchanger, and a casing that houses at least the heat exchanger and the fan unit, wherein the air conditioning apparatus comprises: a fan unit having a propeller fan that rotates in a forward direction or a reverse direction depending on an operation mode of the air conditioner; a fan motor for rotating said propeller fan in said forward direction and said reverse direction to achieve a counterflow heat exchange condition regardless of said operating mode; Equipped with the propeller fan includes fan blades having a symmetrical shape about an axis of symmetry passing through a center of the propeller fan, and depending on the operating mode of the air conditioner, a forward rotation generates an air flow in a direction from the heat exchanger to the fan unit, and a reverse rotation generates a separate air flow from the fan unit to the heat exchanger; the fan blades have a generally planar shape that is angled toward the airflow, the angle of inclination of the planar shape varying with radial position relative to a horizontal plane that passes through a center of the fan blade and is perpendicular to the axis of rotation; Air conditioning units.

2. The air conditioner according to claim 1 , wherein the refrigerant is a non-azeotropic refrigerant.

3. The air conditioner according to claim 1 , wherein the air conditioner uses a refrigerant having a temperature gradient of 3° C. or more.

4. 2. The air conditioning apparatus of claim 1, further comprising a flat area facing the fan blades and extending in the direction of the air flow, and a bellmouth surrounding the propeller fan, the center of the outer circumferential edge of the fan blades being positioned within the level of the flat area facing the fan blades.

5. The air conditioning apparatus of claim 4 , wherein the center of the outer circumferential edge of the fan blade is positioned at the center of the flat region of the bellmouth or shifted from the center of the flat region toward the heat exchanger.

6. An outdoor unit of an air conditioning apparatus, In order to prevent short cycling during reverse rotation of the propeller fan by allowing the airflow discharged from the side to escape away from the front side of the air conditioning device, the air conditioning device is provided with a wind guide integrally disposed on the side of the air conditioning device, and the outdoor unit is The outdoor unit further comprises a heat exchanger, a fan unit, and a non-azeotropic refrigerant that exchanges heat with the heat exchanger, the casing housing the heat exchanger, and the outdoor unit further comprises: a fan unit having a propeller fan that rotates in a forward direction or a reverse direction depending on an operating mode of the air conditioner; a fan motor that rotates the propeller fan in the forward direction and the reverse direction to achieve a counterflow heat exchange state regardless of the operation mode, The propeller fan includes a plurality of fan blades having a symmetrical shape with respect to an axis of symmetry passing through a center of the propeller fan, the fan blades have a generally planar shape that is angled toward the airflow, the angle of inclination of the planar shape relative to a horizontal plane that passes through the center of the fan blade and is perpendicular to the axis of rotation, the angle varying with radial position; Outdoor unit.

7. The outdoor unit of claim 6 , wherein the wind guide has an aperture or apertures positioned away from the front side of the outdoor unit.

8. The outdoor unit according to claim 6 , wherein the wind guide has an aperture that is inclined toward a rear side of the outdoor unit or forms an aperture that is inclined toward the rear side.

9. The outdoor unit of claim 6, wherein the casing has a plurality of slots on the lateral side of the outdoor unit, the plurality of slots being defined by cross bars having a generally rectangular cross section with their apexes facing the heat exchanger.

Images