The present disclosure relates to a centrifugal fan including a scroll casing, an air-conditioning apparatus including the centrifugal fan, and a refrigeration cycle apparatus including the centrifugal fan.
In existing centrifugal fans, air blown out by rotation of an impeller flows, from an inner end portion of a scroll peripheral wall having a volute shape to a discharge port, in a casing whose scroll peripheral wall is expanded in a radial direction of the impeller, and the air pressure thus increases. However, in terms of mounting such an existing centrifugal fan in a unit, there sometimes arise restrictions on expansion of a scroll peripheral wall in a radial direction. To address this, there has been proposed a centrifugal fan in which the sectional area of a passage in a scroll casing is increased with expansion of a scroll peripheral wall in a radial direction inhibited by expanding a scroll side wall in the rotation axis direction of an impeller in addition to expansion of the scroll peripheral wall in the radial direction (see, for example, Patent Literature 1). In the centrifugal fan in Patent Literature 1, the scroll side wall is gradually expanded from an inner end portion in the rotation direction of the impeller, and the height of the scroll side wall is gradually reduced from a most expanded portion in a direction toward the inner end portion. As a result, the centrifugal fan in Patent Literature 1 is capable of smoothly guiding air flowing again to a tongue portion in addition to achieving a pressure increase effect.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2007-127089
However, in the centrifugal fan in Patent Literature 1 the height of the scroll side wall is reduced from the most expanded portion of the scroll side wall in the direction toward the inner end portion, and the height of the part of the side wall toward a discharge port is also reduced. Thus, the velocity of airflow may be increased due to a reduction in the sectional area of the passage in the centrifugal fan in Patent Literature 1 from the most expanded portion toward the discharge port. Accordingly, there is a problem in that the airflow pressure cannot be efficiently increased.
The present disclosure is made to solve such a problem, and an object of the present disclosure is to obtain a centrifugal fan, an air-conditioning apparatus, and a refrigeration cycle apparatus that are capable of efficiently increasing airflow pressure with a side wall expanded in the rotation axis direction of an impeller.
A centrifugal fan according to an embodiment of the present disclosure includes: an impeller having a back plate driven to rotate; and a scroll casing including a peripheral wall provided in parallel with an axial direction of a rotation shaft of the back plate to surround the impeller, and having a volute shape along a rotation direction of the back plate, a first side wall extending along a first edge of the peripheral wall, the first edge being at one end, in the axial direction of the rotation shaft, of the peripheral wall, the first side wall facing a virtual extension of the back plate, the virtual extension of the back plate being perpendicular to the rotation shaft, the first side wall having a first air inlet defined therein and configured to let air in, and a discharge port from which airflow generated by the impeller is discharged. The scroll casing is configured such that an inner end portion of the volute shape of the scrod casing, an expanded portion, and a first edge end portion are arranged in a named order in the rotation direction, the first edge end portion being an end of a first edge, defining the discharge port, of the first side wall, the first edge end portion being farther from the rotation shaft than an other end of the first edge is to the rotation shaft, and distance L1≥distance LM>distance LS is satisfied where LS is a distance between the first side wall at the inner end portion of the volute shape and the virtual extension of the back plate, LM is a distance between the first side wall at the expanded portion and the virtual extension of the back plate, the expanded portion being a portion at which the distance between the first side wall and the virtual extension of the back plate is larger than LS, and L1 is a distance between the first side wall at the first edge end portion and the virtual extension of the back plate.
An air-conditioning apparatus according to another embodiment of the present disclosure includes the centrifugal fan and a heat exchanger provided to face the discharge port of the centrifugal fan.
A refrigeration cycle apparatus according to still another embodiment of the present disclosure includes the centrifugal fan.
According to the embodiments of the present disclosure, the scroll casing of the centrifugal fan is configured such that the inner end portion, the expanded portion, and the first edge end portion are arranged in a named order in the rotation direction and such that distance L1=distance LM>distance LS is satisfied. As a result, air flowing in the scroll casing flows toward the discharge port with the pressure thereof increasing along with expansion of the scroll side wall. In addition, part of the air toward the inner end portion can smoothly flow again to the inner end portion due to the height of the first side wall being reduced such that distance LM>distance LS is satisfied. Furthermore, the scroll casing is configured such that distance L1distance LM is satisfied. Thus, the scroll casing is configured without the sectional area of the passage reduced from the expanded portion toward the discharge port. Accordingly, the centrifugal fan, the air-conditioning apparatus, and the refrigeration cycle apparatus having this configuration are capable of efficiently increasing airflow pressure with expansion of the side wall.
A centrifugal fan 1 according to an embodiment of the present disclosure will be described below with reference to the drawings, for example. In addition, an air-conditioning apparatus 40 and a refrigeration cycle apparatus 50 according to embodiments of the present disclosure will be described with reference to the drawings, for example. For example, the relative size relationships or the shapes of the components in the following drawings including
First, the basic structure of the centrifugal fan 1 will be described by using
The impeller 2 is driven to rotate by, for example, a motor (not illustrated) and forcibly sends air outward in radial directions with the centrifugal force generated by the rotation. As illustrated in
The blades 2d are provided on the circumference around the axial portion 2b. The base ends of the blades 2d are fixed to the back plate 2a. The blades 2d are provided on both sides of the back plate 2a in the axial direction of the rotation shaft RS of the impeller 2. The blades 2d are provided on the peripheral portion 2a1 of the back plate 2a with certain spaces therebetween. The blades 2d each have, for example, a curved rectangular plate-like shape and are each provided to extend in a radial direction or to be inclined at a predetermined angle relative to a radial direction. The blades 2d are each formed into a two-dimensional blade in which the same sectional shape is continuous in the axial direction of the rotation shaft RS but may be each formed into a three-dimensional blade having a twisted shape. The blades 2d are provided to stand substantially perpendicularly to the back plate 2a, but the configuration thereof is not limited thereto. The blades 2d may be provided to be inclined relative to a direction perpendicular to the back plate 2a.
As illustrated in
As illustrated in
The impeller 2 is driven to rotate around the rotation shaft RS by driving the motor (not illustrated). By rotating the impeller 2, gas outside the centrifugal fan 1 is suctioned into the spaces surrounded by the back plate 2a and the blades 2d through air inlets 5, which are formed in the scroll casing 4, and the air inlets 2e of the impeller 2. By rotating the impeller 2, the air suctioned into the spaces surrounded by the back plate 2a and the blades 2d is then sent outward in a radial direction through a space between each blade 2d and the corresponding adjacent blade 2d.
As illustrated in
The scroll portion 41 defines an air passage in which the dynamic pressure of airflow generated by the impeller 2 is converted into a static pressure. The scroll portion 41 includes side walls 4a, which have the respective air inlets 5 defined therein and configured to let air in and which surround the impeller 2 in the axial direction of the rotation shaft RS of the axial portion 2b forming the impeller 2, and a peripheral wall 4c, which surrounds the impeller 2 in radial directions of the rotation shaft RS of the axial portion 2b forming the impeller 2. In addition, the scroll portion 41 includes a tongue portion 43, which has a curved surface between the discharge portion 42 and an inner end portion 41s of the peripheral wall 4c and which is a restriction portion required for blowing out, in a centrifugal direction, the air that has flowed in through the air inlets 5 and increasing the air pressure. A radial direction of the rotation shaft RS is a direction perpendicular to the rotation shaft RS. The internal space of the scroll portion 41 formed by the peripheral wall 4c and the side walls 4a is a space in which the air that has blown out from the impeller 2 flows along the peripheral wall 4c.
As illustrated in
As illustrated in
As illustrated in
The peripheral wall 4c guides, along a curved wall surface thereof, airflow generated by the impeller 2 to a discharge port 42a via the scroll portion 41. The peripheral wall 4c is a wall provided between the side walls 4a facing each other and has a curved surface in a rotation direction R of the impeller 2. For example, the peripheral wall 4c is provided in parallel with the axial direction of the rotation shaft RS of the impeller 2 to surround the impeller 2. The peripheral wall 4c may be inclined relative to the axial direction of the rotation shaft RS of the impeller 2 and is not limited to the peripheral wall 4c provided in parallel with the axial direction of the rotation shaft RS. The peripheral wall 4c surrounds the impeller 2 in radial directions of the rotation shaft RS and has an inner circumferential surface facing the blades 2d. The peripheral wall 4c faces the air discharge sides of the blades 2d of the impeller 2. As illustrated in
The peripheral wall 4c has a volute shape along the rotation direction R. Examples of such a volute shape include volute shapes based on a logarithmic spiral, an Archimedean spiral, and an involute curve. The inner circumferential surface of the peripheral wall 4c is a surface smoothly curved in the circumferential direction of the impeller 2 from the inner end portion 41s, which is an inner end of the volute shape, to the outer end portion 41b, which is an outer end of the volute shape. With such a configuration, the air sent out from the impeller 2 flows smoothly between the impeller 2 and the peripheral wall 4c in a direction toward the discharge portion 42. Thus, in the scroll casing 4, the static pressure of air increases efficiently from the tongue portion 43 toward the discharge portion 42.
The discharge portion 42 defines the discharge port 42a from which the airflow that has been generated by the impeller 2 and that has passed through the scroll portion 41 is discharged. The discharge portion 42 is made of a hollow pipe whose section orthogonal to a direction in which air flows along the peripheral wall 4c has a rectangular shape. The discharge portion 42 defines a passage for guiding, to be discharged to the outside of the scroll casing 4, the air that flows between the peripheral wall 4c and the impeller 2 after being sent out from the impeller 2.
As illustrated in
The scroll casing 4 has the tongue portion 43 between the diffuser plate 42c of the discharge portion 42 and the inner end portion 41s of the peripheral wall 4c. The tongue portion 43 is formed with a predetermined curvature radius. The peripheral wall 4c is smoothly continuous with the diffuser plate 42c via the tongue portion 43. The tongue portion 43 inhibits air from flowing from the outer end into the inner end of the volute-shaped passage. The tongue portion 43 is provided in an upstream section of the air passage and has a function of separating air flowing in the rotation direction R of the impeller 2 and air flowing in the discharge direction from a downstream section of the air passage toward the discharge port 42a. In addition, the static pressure of air flowing into the discharge portion 42 increases during the air passing through the scroll casing 4 and becomes higher than that in the scroll casing 4, Thus, the tongue portion 43 has a function of separating areas different from each other in pressure as described above.
Here, as illustrated in
Next, as illustrated in
The scroll casing 4 is configured such that the inner end portion 41s, the expanded portion 41m, and the first edge end portion 42a11 are arranged in a named order in the rotation direction R and such that distance L1≥Ldistance LM≥distance LS is satisfied. Preferably, the scroll casing 4 is configured such that distance L1L-distance L2≥distance LS is satisfied.
In addition, as illustrated in
In addition, as illustrated in
Furthermore, as represented by a dashed line DL in
As illustrated in
An expansion start portion 41p is a portion at which the distance between the first side wall 4a1 and the extension L starts to increase in the rotation direction R of the impeller 2. In the modified scroll casing 4, when the angle at the position of the inner end portion 41s is 0 degrees, the expansion start portion 41p is formed between a position at 0 degrees and a position at 180 degrees in the rotation direction R.
Thus, the modified scroll casing 4 is configured such that the inner end portion 41s, the expansion start portion 41p, the expanded portion 41m, and the first edge end portion 42a11 are arranged in a named order in the rotation direction R and such that distance L1≥distance LM>distance LS is satisfied. Similarly to the scroll casing 4 described above, preferably, the modified scroll casing 4 is configured such that distance L1≥distance L2≥distance LS is satisfied.
The relationship between the first side wall 4a1 and the virtual extension L has been described above. This relationship also applies to the relationship between the second side wall 4a2 and the virtual extension L. Thus, as illustrated in
Next, as illustrated in
The scroll casing 4 is configured such that the inner end portion 41s, the second expanded portion 41m2, and the third edge end portion 42a21 are arranged in a named order in the rotation direction R and such that distance L3-distance LM2>distance LS2 is satisfied. Preferably, the scroll casing 4 is configured such that distance L3Aistance L4≥distance LS2 is satisfied.
The relationship between a scroll side wall height H and an angle θ in the scroll portion 41 illustrated in
In addition, the scroll casing 4 is configured such that the scroll side wall height H reduces in the rotation direction R from the second expanded portion 41m2 to the inner end portion 41s. Thus, the scroll casing 4 is configured such that the distance between the second side wall 4a2 and the extension L gradually reduces in the rotation direction R of the impeller 2 from the second expanded portion 41m2 toward the inner end portion 41s.
In addition, the scroll casing 4 is configured such that the scroll side wall height H is constant from the second expanded portion 41m2 to the third edge end portion 42a21. Thus, the scroll casing 4 is configured such that the distance between the second side wall 4a2 and the extension L is constant from the second expanded portion 41m2 toward the third edge end portion 42a21.
Furthermore, the scroll casing 4 may be configured such that the scroll side wall height H increases from the second expanded portion 41m2 to the third edge end portion 42a21. Thus, the scroll casing 4 may be configured such that the distance between the second side wall 4a2 and the extension L increases from the second expanded portion 41m2 toward the third edge end portion 42a21,
Furthermore, in the modified scroll casing 4, when the angle at the position of the inner end portion 41s in the second side wall 4a2 is 0 degrees, a second expansion start portion 41p2 is formed between a position at 0 degrees and a position at 180 degrees in the rotation direction R. The expansion start portion 41p in the first side wall 4a1 and the second expansion start portion 41p2 in the second side wall 4a2 are formed at the same position in the rotation direction R. However, the configuration of the expansion start portion 41p in the first side wall 4a1 and the second expansion start portion 41p2 in the second side wall 4a2 is not limited to the configuration in which they are formed at the same position in the rotation direction R. The expansion start portion 41p in the first side wall 4a1 and the second expansion start portion 41p2 in the second side wall 4a2 may be formed at different positions in the rotation direction R.
When the impeller 2 rotates, air outside the scroll casing 4 is suctioned into the scroll casing 4 through the air inlets 5 formed at the respective sides of the impeller 2. In this case, the air suctioned into the scroll casing 4 is suctioned into the impeller 2 by being guided through the bell mouths 3. The air suctioned into the impeller 2 becomes, in the process of passing through the spaces between the blades 2d, airflow to which a dynamic pressure and a static pressure are imparted, and the airflow is blown out toward the outside of the impeller 2 in radial directions. The dynamic pressure of the airflow blown out from the impeller 2 is converted into a static pressure during the airflow being guided between the inside of the peripheral wall 4c and the blades 2d in the scroll portion 41. After passing through the scroll portion 41, the airflow is blown outside the scroll casing 4 from the discharge port 42a formed in the discharge portion 42. In this case, part of the airflow does not move toward the discharge port 42a after passing through the scroll portion 41 but flows again into the scroll portion 41 from the tongue portion 43.
The scroll casing 4 of the centrifugal fan 1 is configured such that the inner end portion 41s, the expanded portion 41m, and the first edge end portion 42a11 are arranged in a named order in the rotation direction R and such that distance L1≥distance LM>distance LS is satisfied. As a result, air flowing in the scroll casing 4 flows toward the discharge port 42a with the pressure thereof increasing due to an increase in the sectional area of the passage along with expansion of the side wall 4a. In addition, part of the air toward the inner end portion 41s can smoothly flow again to the inner end portion 41s due to the height of the first side wall 4a1 being reduced such that distance LM>distance LS is satisfied. Furthermore, the scroll casing 4 is configured such that distance L1≥distance LM is satisfied. Thus, the scroll casing 4 is configured without the sectional area of the passage reduced from the expanded portion 41m toward the discharge port 42a Accordingly, the centrifugal fan 1 having this configuration is capable of efficiently increasing airflow pressure,
In addition, the scroll casing 4 of the centrifugal fan 1 is configured such that the inner end portion 41s, the second expanded portion 41m2, and the third edge end portion 42a21 are arranged in a named order in the rotation direction R and such that distance L3≥distance LM2>distance LS2 is satisfied. As a result, air flowing in the scroll casing 4 flows toward the discharge port 42a with the pressure thereof increasing due to an increase in the sectional area of the passage along with expansion of the side wall 4a. In addition, part of the air toward the inner end portion 41s can smoothly flow again to the inner end portion 41s due to the height of the second side wall 4a2 being reduced such that distance LM2>distance LS2 is satisfied. Furthermore, the scroll casing 4 is configured such that distance L3≥distance LM2 is satisfied, Thus, the scroll casing 4 is configured without the sectional area of the passage reduced from the second expanded portion 41m2 toward the discharge port 42a, Accordingly, the centrifugal fan 1 having this configuration is capable of efficiently increasing airflow pressure. In the centrifugal fan 1, the first side wall 4a1 and the second side wall 4a2 each have the above relationship. Thus, it is possible to make the configuration of the centrifugal fan 1 suitable, in terms of, for example, the air suction amount, for the form of a unit in which the centrifugal fan 1 is to be mounted.
In addition, in the scroll casing 4, the distance between the side wall 4a and the extension L gradually increases in the rotation direction R from the inner end portion 41s toward the expanded portion 41m. Thus, in the centrifugal fan 1, the sectional area of the passage in the scroll casing 4 can be increased with expansion thereof in a radial direction inhibited.
In addition, the expansion start portion 41p is formed between a position at 0 degrees and a position at 180 degrees in the rotation direction R. When the centrifugal fan 1 has a configuration in which the side wall 4a is expanded, and the amount of suction air flowing in from the vicinity of the inner end portion 41s is excessively small, air may not flow sufficiently in the air passage formed between the impeller 2 and the scroll casing 4. Thus, airflow separation occurs everywhere at an inner wall surface of the scroll casing 4, and, actually, this configuration may reduce efficiency. In the centrifugal fan 1, the expansion start portion 41p is formed between a position at 0 degrees and a position at 180 degrees in the rotation direction R. Thus, even when the amount of suction air flowing in from the vicinity of the inner end portion 41s is excessively small, it is possible to start to expand the side wall 4a at a position where there is a certain amount of suction air.
In addition, the scroll casing 4 is configured such that distance L1≥distance L2≥distance LS is satisfied, or the scroll casing 4 is configured such that distance L3≥distance L4≥distance LS2 is satisfied. This configuration of the scroll casing 4 enables an excessive restriction of a discharge flow to be inhibited and enables an airflow velocity increase effect to be reduced.
In addition, the expanded portion 41m is formed between, in the rotation direction R, a position at 180 degrees relative to the inner end portion 41s and a position where the line connecting the rotation shaft RS and the first edge end portion 42a11 forms the first angle θ1, or the second expanded portion 41m2 is formed between, in the rotation direction R, a position at 180 degrees relative to the inner end portion 41s and a position where the line connecting the rotation shaft RS and the third edge end portion 42a21 forms the second angle θ2. Thus, in the centrifugal fan 1, the sectional area of the passage in the scroll casing 4 can be increased with expansion thereof in a radial direction inhibited. Accordingly, air flowing in the scroll casing 4 flows toward the discharge port 42a with the pressure thereof increasing with expansion of the side walls 4a.
As illustrated in
The bulging portion 14 may be formed at one of the first side wall 4a1 and the second side wall 4a2 or at each of the first side wall 4a1 and the second side wall 4a2. In addition, the position, in the rotation direction R from the inner end portion 41s, where the bulging portion 14 is formed at the first side wall 4a1 and the position, in the rotation direction R from the inner end portion 41s, where the bulging portion 14 is formed at the second side wall 4a2 may be the same or different.
The scroll casing 4 of the centrifugal fan 1B according to Embodiment 3 includes a second side wall 4a21 extending along the second edge 4c12 of the peripheral wall 4c, the second edge 4c12 being at the other end, in the axial direction of the rotation shaft RS, of the peripheral wall 4c, the second side wall 4a21 facing the extension L, the second side wall 4a21 having the second air inlet 5b defined therein and configured to let air in. A distance LM21 is the distance between the second side wall 4a21 at the second expanded portion 41m2 and the extension L. A distance LS21 is the distance between the second side wall 4a21 at the inner end portion 41s of the volute shape and the extension L. The centrifugal fan 1B has the relationship that the distance LM21 is substantially equal to the distance LS21. That is, the distance between the second side wall 4a21 and the extension L is substantially constant in the rotation direction R. In the centrifugal fan 1B, the feature in which the side wall 4a is expanded in the direction along the rotation shaft RS is applied only to the first side wall 4a1. The centrifugal fan 1B includes the scroll casing 4 whose respective suction sides have different shapes.
When the centrifugal fan 1 according to Embodiment 1 is mounted in a unit, and, for example, an obstacle exists at one of the side walls 4a, the respective amounts of air suctioned by the left side and the right side of the centrifugal fan 1 are different from each other. In this case, when the feature in which the side wall 4a is expanded in the direction along the rotation shaft RS is applied to the side wall 4a at which the amount of suction air is small, the passage in the scroll casing 4 of the centrifugal fan 1 is expanded excessively to be out of proportion to the amount of air. In this case, airflow separation may occur at the inner wall surface of the scroll casing 4 of the centrifugal fan 1. On the other hand, in the centrifugal fan 1B, the distance between the second side wall 4a21 and the extension L is constant in the rotation direction R. In the centrifugal fan 1B, application of the second side wall 4a21 to the side wall 4a at which the amount of suction air is small enables the passage in the scroll casing 4 to have an area appropriate for the amount of air. As a result, the centrifugal fan 1B is capable of inhibiting airflow separation from occurring at the inner wall surface of the scroll casing 4.
The scroll casing 4 of the centrifugal fan 10 according to Embodiment 4 includes a second side wall 4a23 extending along the second edge 4c12 of the peripheral wall 4c, the second edge 4c12 being at the other end, in the axial direction of the rotation shaft RS, of the peripheral wall 4c, the second side wall 4a23 facing the extension L. The second side wall 4a23 is formed to surround the impeller 2 in the axial direction of the rotation shaft RS. The second side wall 4a23 has a plate-like shape. The second side wall 4a23 does not have the air inlet 5. In the centrifugal fan 10, the feature in which the side wall 4a is expanded in the direction along the rotation shaft RS is applied only to the first side wall 4a1. The centrifugal fan 10 includes the scroll casing 4 that is a single suction scroll casing.
The first side wall 4a1 of the centrifugal fan 10 according to Embodiment 4 and the first side wall 4a1 of the centrifugal fan 1 according to Embodiment 1 have the same configuration. Thus, the centrifugal fan 10 according to Embodiment 4 including the scroll casing 4 that is a single suction scroll casing is capable of achieving an effect similar to that of the centrifugal fan 1 according to Embodiment 1.
As illustrated in
The case 16 accommodates two centrifugal fans 1, a motor 6, and the heat exchanger 10. The centrifugal fans 1 each include the scroll casing 4 including the impeller 2 and the bell mouth 3. The motor 6 is supported by a motor support 9a, which is fixed to the top portion 16a of the case 16. The motor 6 has an output shaft 6a. The output shaft 6a is provided to extend in parallel with the side having the case air inlet 18 and the side having the case discharge port 17 of the side portions 16c. As illustrated in
As illustrated in
The heat exchanger 10 is provided to face the discharge ports 42a of the centrifugal fans 1. The heat exchanger 10 is provided in an air passage in the case 16 for air discharged by the centrifugal fans 1. The heat exchanger 10 adjusts the temperature of air suctioned into the case 16 from the case air inlet 18 and to be blown out into an air-conditioned space from the case discharge port 17. A heat exchanger having a known structure is applicable to the heat exchanger 10.
When the impellers 2 are rotated by driving the motor 6, air in an air-conditioned space is suctioned into the case 16 through the case air inlet 18. The air suctioned into the case 16 is guided into the bell mouths 3 and suctioned into the impellers 2. The air suctioned into the impellers 2 is blown out in radial directions of the impellers 2. The air blown out from the impellers 2 passes through the scroll casings 4, is blown out from the discharge ports 42a of the scroll casings 4, and is then supplied to the heat exchanger 10. The air supplied to the heat exchanger 10 is subjected to heat exchange during passing through the heat exchanger 10, and the temperature and humidity of the air are adjusted. The air that has passed through the heat exchanger 10 is blown out into the air-conditioned space from the case discharge port 17.
The air-conditioning apparatus 40 according to Embodiment 5 includes, for example, the centrifugal fan 1 according to Embodiment 1 and is thus capable of achieving an effect similar to that of the centrifugal fan 1 according to Embodiment 1. Accordingly, for example, the air-conditioning apparatus 40 is capable of sending, to the heat exchanger 10, air whose pressure has been efficiently increased by the centrifugal fan 1.
The refrigeration cycle apparatus 50 according to Embodiment 6 performs air conditioning by transferring heat between outdoor air and indoor air via refrigerant to heat or cool an indoor space. The refrigeration cycle apparatus 50 according to Embodiment 6 includes an outdoor unit 100 and an indoor unit 200. In the refrigeration cycle apparatus 50, a refrigerant circuit in which refrigerant circulates is formed by connecting the outdoor unit 100 and the indoor unit 200 by refrigerant pipes 300 and 400. The refrigerant pipe 300 is a gas pipe in which gas phase refrigerant flows. The refrigerant pipe 400 is a liquid pipe in which liquid phase refrigerant flows. Two-phase gas-liquid refrigerant may flow in the refrigerant pipe 400. In the refrigerant circuit of the refrigeration cycle apparatus 50, a compressor 101, a flow switching device 102, an outdoor heat exchanger 103, an expansion valve 105, and an indoor heat exchanger 201 are successively connected via refrigerant pipes.
The outdoor unit 100 includes the compressor 101, the flow switching device 102, the outdoor heat exchanger 103, and the expansion valve 105. The compressor 101 compresses and discharges suctioned refrigerant. The flow switching device 102 is, for example, a four-way valve, that is, a device configured to switch between directions in which refrigerant flows. The refrigeration cycle apparatus 50 is capable of realizing a heating operation or a cooling operation by switching refrigerant flows with the flow switching device 102 on the basis of instructions from a controller 110.
The outdoor heat exchanger 103 exchanges heat between refrigerant and outdoor air. The outdoor heat exchanger 103 functions as an evaporator in the heating operation and exchanges heat between low-pressure refrigerant flowing in through the refrigerant pipe 400 and outdoor air to evaporate and gasify the refrigerant. The outdoor heat exchanger 103 functions as a condenser in the cooling operation and exchanges heat between outdoor air and refrigerant that has been compressed by the compressor 101 and that has flowed in from the flow switching device 102 to condense and liquify the refrigerant. An outdoor fan 104 is provided at the outdoor heat exchanger 103 to increase the efficiency of heat exchange between refrigerant and outdoor air. An inverter may be attached to the outdoor fan 104, and the operating frequency of a fan motor may be varied by the inverter to vary the rotation speed of the fan. The expansion valve 105 is an expansion device (flow control unit). The expansion valve 105 functions as an expansion valve by adjusting the amount of refrigerant flowing through the expansion valve 105. The expansion valve 105 adjusts refrigerant pressure by varying the opening degree thereof. For example, when the expansion valve 105 is formed by an electronic expansion valve, the opening degree is adjusted on the basis of instructions from the controller 110.
The indoor unit 200 includes the indoor heat exchanger 201, which is configured to exchange heat between refrigerant and indoor air, and the indoor fan 202, which is configured to adjust the flow of air to be subjected to heat exchange in the indoor heat exchanger 201, The indoor heat exchanger 201 functions as a condenser in the heating operation and exchanges heat between indoor air and refrigerant flowing in through the refrigerant pipe 300 to condense and liquify the refrigerant, and the refrigerant then flows out toward the refrigerant pipe 400. The indoor heat exchanger 201 functions as an evaporator in the cooling operation and exchanges heat between indoor air and refrigerant whose pressure is reduced by the expansion valve 105 to evaporate and gasify the refrigerant that has received heat of the air, and the refrigerant then flows out toward the refrigerant pipe 300. The indoor fan 202 is provided to face the indoor heat exchanger 201. One or more of the centrifugal fan 1 according to Embodiment 1 to the centrifugal fan 1 to the centrifugal fan 1C according to Embodiment 4 are applicable to the indoor fan 202. The operating speed of the indoor fan 202 is determined by user settings. An inverter may be attached to the indoor fan 202, and the operating frequency of a fan motor (not illustrated) may be varied by the inverter to vary the rotation speed of the impeller 2.
Next, the cooling operation will be described as an operation example of the refrigeration cycle apparatus 50. High-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 101 flows into the outdoor heat exchanger 103 via the flow switching device 102. The gas refrigerant that has flowed into the outdoor heat exchanger 103 is condensed into low-temperature refrigerant by being subjected to heat exchange with outdoor air sent by the outdoor fan 104, and the low-temperature refrigerant flows out from the outdoor heat exchanger 103. The refrigerant that has flowed out from the outdoor heat exchanger 103 is expanded and decompressed into low-temperature, low-pressure two-phase gas-liquid refrigerant by the expansion valve 105. The two-phase gas-liquid refrigerant flows into the indoor heat exchanger 201 of the indoor unit 200 and is evaporated into low-temperature, low-pressure gas refrigerant by being subjected to heat exchange with indoor air sent by the indoor fan 202, and the low-temperature, low-pressure gas refrigerant flows out from the indoor heat exchanger 201 In this case, the indoor air that has been cooled by removing heat by the refrigerant becomes conditioned air, and the conditioned air is blown out into an air-conditioned space from a discharge port of the indoor unit 200, The gas refrigerant that has flowed out from the indoor heat exchanger 201 is suctioned into the compressor 101 via the flow switching device 102 and is compressed again. A series of the above operations is repeated.
Next, the heating operation will be described as an operation example of the refrigeration cycle apparatus 50. High-temperature, high-pressure gas refrigerant compressed and discharged by the compressor 101 flows into the indoor heat exchanger 201 of the indoor unit 200 via the flow switching device 102. The gas refrigerant that has flowed into the indoor heat exchanger 201 is condensed into low-temperature refrigerant by being subjected to heat exchange with indoor air sent by the indoor fan 202, and the low-temperature refrigerant flows out from the indoor heat exchanger 201. In this case, the indoor air that has been heated by receiving heat from the gas refrigerant becomes conditioned air, and the conditioned air is blown out into an air-conditioned space from the discharge port of the indoor unit 200. The refrigerant that has flowed out from the indoor heat exchanger 201 is expanded and decompressed into low-temperature, low-pressure two-phase gas-liquid refrigerant by the expansion valve 105. The two-phase gas-liquid refrigerant flows into the outdoor heat exchanger 103 of the outdoor unit 100 and is evaporated into low-temperature, low-pressure gas refrigerant by being subjected to heat exchange with outdoor air sent by the outdoor fan 104, and the low-temperature, low-pressure gas refrigerant flows out from the outdoor heat exchanger 103. The gas refrigerant that has flowed out from the outdoor heat exchanger 103 is suctioned into the compressor 101 via the flow switching device 102 and is compressed again. A series of the above operations is repeated.
The refrigeration cycle apparatus 50 according to Embodiment 6 includes, for example, the centrifugal fan 1 according to Embodiment 1 and is thus capable of achieving an effect similar to that of the centrifugal fan 1 according to Embodiment 1, Accordingly, for example, the refrigeration cycle apparatus 50 is capable of sending, to the indoor heat exchanger 201, air whose pressure has been efficiently increased by the indoor fan 202.
Combinations of Embodiments 1 to 6 described above can be implemented. The configurations in the embodiments above are examples. Thus, the configurations can be combined with other known techniques, and some of the configurations can be omitted or modified without departing from the gist.
1: centrifugal fan, 1A: centrifugal fan, 1B: centrifugal fan, 1C: centrifugal fan, 2: impeller, 2a: back plate, 2a1: peripheral portion, 2b: axial portion, 2c: side plate, 2c1: first side plate, 2c2: second side plate, 2d: blade, 2e: air inlet, 3: bell mouth, 4: scroll casing, 4a: side wall, 4a1: first side wall, 4a2: second side wall, 4a21: second side wall, 4a23: second side wall, 4c: peripheral wall, 4c11: first edge, 4c12: second edge, 5: air inlet, 5a: first air inlet, 5b: second air inlet, 6: motor, 6a: output shaft, 9a: motor support, 10: heat exchanger, 14: bulging portion, 16: case, 16a: top portion, 16b: bottom portion, 16c: side portion, 17: case discharge port, 18: case air inlet, 19: partition plate, 30: unit, 31: wall, 40: air-conditioning apparatus, 41: scroll portion, 41b: outer end portion, 41m: expanded portion, 41m2: second expanded portion, 41p: expansion start portion, 41p2: second expansion start portion, 41s: inner end portion, 42: discharge portion, 42a: discharge port, 42a11: first edge end portion, 42a12: second edge end portion, 42a21: third edge end portion, 42a22: fourth edge end portion, 42b: extended plate, 42c: diffuser plate, 42d: first edge, 42e: second edge, 43: tongue portion, 50: refrigeration cycle apparatus, 100: outdoor unit, 101: compressor, 102: flow switching device, 103: outdoor heat exchanger, 104: outdoor fan, 105: expansion valve, 110: controller, 200: indoor unit, 201: indoor heat exchanger, 202: indoor fan, 300: refrigerant pipe, 400: refrigerant pipe
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2019/023397 | 6/13/2019 | WO | 00 |