U.S. patent application number 13/814537 was filed with the patent office on 2013-05-23 for air-sending device of outdoor unit, outdoor unit, and refrigeration cycle apparatus.
This patent application is currently assigned to MITSUBISHI ELECTRIC CORPORATION. The applicant listed for this patent is Hiroki Okazawa. Invention is credited to Hiroki Okazawa.
Application Number | 20130125579 13/814537 |
Document ID | / |
Family ID | 45831084 |
Filed Date | 2013-05-23 |
United States Patent
Application |
20130125579 |
Kind Code |
A1 |
Okazawa; Hiroki |
May 23, 2013 |
AIR-SENDING DEVICE OF OUTDOOR UNIT, OUTDOOR UNIT, AND REFRIGERATION
CYCLE APPARATUS
Abstract
A propeller fan rotates about a vertical axis. A bellmouth has a
wall extending such that an air passage on an outlet side spreads
outward. The bellmouth has a shape satisfying: H/D.gtoreq.0.04
between a length H of the sloping surface in a direction of the
rotation axis from an end on an inlet; side to an end on the outlet
side and a fan diameter D of the propeller fan
0<.theta..gtoreq.60.degree. for an angle .theta. formed between
a line connecting the ends of the sloping surface and the rotation
axis; and L/L0.gtoreq.0.5 between a length L in the direction of
the rotation axis from an opening on the inlet side to the end of
the sloping surface on the inlet side and a length L0 of the blades
of the propeller fan in the direction of the rotational axis.
Inventors: |
Okazawa; Hiroki; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Okazawa; Hiroki |
Tokyo |
|
JP |
|
|
Assignee: |
MITSUBISHI ELECTRIC
CORPORATION
Tokyo
JP
|
Family ID: |
45831084 |
Appl. No.: |
13/814537 |
Filed: |
September 14, 2010 |
PCT Filed: |
September 14, 2010 |
PCT NO: |
PCT/JP2010/005596 |
371 Date: |
February 6, 2013 |
Current U.S.
Class: |
62/507 ;
415/220 |
Current CPC
Class: |
F25D 17/06 20130101;
F04D 29/522 20130101; F24F 1/38 20130101 |
Class at
Publication: |
62/507 ;
415/220 |
International
Class: |
F04D 29/52 20060101
F04D029/52; F25D 17/06 20060101 F25D017/06 |
Claims
1. An air-sending device of an outdoor unit comprising: a propeller
fan that rotates about a rotation axis extending in a direction of
gravity and includes a plurality of blades that produce a flow of
gas in a direction opposite to the direction of gravity; and a
bellmouth rectifying the gas, the bellmouth having an annular wall
extending in a direction of rotation of the blades of the propeller
fan on an outer side with respect to outer peripheral edges of the
blades, wherein, the bellmouth has a wall forming a sloping surface
extending such that an air passage on an outlet side spreads
outward in a case where an operating point of the propeller fan is
on an open side with respect to a surging zone, and the bellmouth
has a shape satisfying conditions represented as a relationship of
H/D.gtoreq.0.04 between a length H of the sloping surface in a
direction of the rotation axis from an end on an inlet side to an
end on the outlet side and a fan diameter D of the propeller fan, a
relationship of 0<.theta..gtoreq.60.degree. for an angle .theta.
formed between a line connecting the ends of the sloping surface
and the rotation axis, and a relationship of L/L0.gtoreq.0.5
between a length L in the direction of the rotation axis from an
opening on the inlet side to the end of the sloping surface on the
inlet side and a length L0 of the blades of the propeller fan in
the direction of the rotation axis.
2. The air-sending device of the outdoor unit of claim 1, wherein
the bellmouth includes a wall extending in the direction of the
rotation axis from the end of the sloping surface on the outlet
side, the wall being provided at an opening on the outlet side.
3. The air-sending device of the outdoor unit of claim 1, further
comprising a fan guard having a grating that covers the opening on
the outlet side, wherein an orientation of the grating in the
direction of the rotation axis is parallel to the rotation
axis.
4. The air-sending device of the outdoor unit of claim 1, wherein
the propeller fan has a rib provided on each of the blades over an
entirety of an outer peripheral edge or a part of the outer
peripheral edge excluding two ends thereof and extending
substantially parallel to the rotation axis toward the inlet
side.
5. The air-sending device of the outdoor unit of claim 1, wherein a
part of the opening of the bellmouth on the outlet side is deformed
according to an area defined by dimensions of a casing of the
outdoor unit.
6. The air-sending device of the outdoor unit of claim 1, wherein
the bellmouth has a curved surface provided at the opening on the
inlet side and configured such that an integrated value of radii of
curvature of the curved surface over an entire circumference
becomes largest under conditions for provision or installation.
7. An outdoor unit comprising: a compressor that compresses a
refrigerant; an outdoor-side heat exchanger that exchanges heat
between the refrigerant and air; and the air-sending device of
claim 1 that allows the air to pass through the outdoor-side heat
exchanger.
8. A refrigeration cycle apparatus comprising: a load unit having a
plurality of load-side heat exchangers that each exchange heat
between a subject of heat exchange and a refrigerant, and flow
control means that adjusts a flow rate of the refrigerant made to
flow into the load-side heat exchangers; and the outdoor unit of
claim 7, wherein the load unit and the outdoor unit are connected
by pipes to constitute a refrigerant circuit.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. national stage application of
PCT/JP2010/005596 filed on Sep. 14, 2010, the disclosure of which
is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an outdoor unit and the
like that each include an air-sending device including a propeller
fan and a bellmouth.
BACKGROUND
[0003] There is an air-sending device (fan unit) that sends air
(that performs cooling, heat exhaust, and so forth) while producing
a flow of air by rotating a propeller fan having blades (a
propeller). Such an air-sending device including a propeller fan is
applied to a wide variety of fields such as outdoor devices
(outdoor units) for refrigeration and air-conditioning apparatuses,
refrigerators, electric fans, and cooling devices for computers and
the like.
[0004] Some of such air-sending devices each include, for example,
a bellmouth with a wall extending in the direction of rotation of
the propeller fan. Such a bellmouth generally has an opening
spreading outward so that air is blown out smoothly (see Patent
Literatures 1 and 2, for example).
CITATION LIST
Patent Literature
[0005] Patent Literature 1: Japanese Patent No. 3087876 [0006]
Patent Literature 2: Japanese Patent No. 3199931
SUMMARY
[0007] For example, in the air-sending device described above in
which the opening simply spreads outward, sound regarded as noise
increases and the fan efficiency is reduced. For example, in a case
where the above air-sending device is provided in an outdoor unit
of an air-conditioning apparatus, noise from the outdoor unit
generated with the rotation of the propeller fan may annoy
neighborhood residents. Therefore, there is a need to reduce noise
of outdoor unit. Meanwhile, in recent years, there have been a need
for air-conditioning apparatuses having high energy efficiency for
prevention of global warming. To achieve high energy efficiency,
measures such as increasing the air flow rate of the outdoor unit
is effective. Basically, however, noise increases with the air flow
rate. Moreover, air-conditioning apparatuses or the like are
typically operated without any stoppage or for a long time.
Therefore, it is also important to reduce power consumed by the
air-sending device itself.
[0008] In view of the above, it is an object of the present
invention to provide an outdoor unit of a refrigeration cycle
apparatus and the like, the outdoor unit and the like each
including an air-sending device in which the generation of noise
and the increase in power consumption are further suppressed.
Solution to Problem
[0009] An air-sending device of an outdoor unit according to the
present invention includes a propeller fan that rotates about a
rotation axis extending in a direction of gravity and includes a
plurality of blades that produce a flow of gas in a direction
opposite to the direction of gravity, and a bellmouth for
rectifying the gas, the bellmouth having an annular wall extending
in a direction of rotation of the blades of the propeller fan on an
outer side with respect to outer peripheral edges of the blades.
The bellmouth has a wall forming a sloping surface extending such
that an air passage on an outlet side spreads outward. The
bellmouth has a shape satisfying conditions represented as a
relationship of H/D.gtoreq.0.04 between a length H of the sloping
surface in a direction of the rotation axis from an end on an inlet
side to an end on the outlet side and a fan diameter D of the
propeller fan, a relationship of 0<.theta..gtoreq.60.degree. for
an angle .theta. formed between a line connecting the ends of the
sloping surface and the rotation axis, and a relationship of
L/L0.gtoreq.0.5 between a length L in the direction of the rotation
axis from an opening on the inlet side to the end of the sloping
surface on the inlet side and a length L0 of the blades of the
propeller fan in the direction of the rotational axis.
[0010] In the air-sending device of an outdoor unit according to
the present invention, the bellmouth has the sloping surface
extending such that the air passage on the outlet side spreads
outward. Furthermore, with respect to the propeller fan, the
bellmouth has a shape satisfying the relationships of
L/L0.gtoreq.0.5, 0<.theta.60.degree., and H/D.gtoreq.0.04.
Therefore, the relationship between the static pressure and the air
flow rate on an open side can be made closer to the relationship
between the static pressure and the air flow rate in a surging zone
without increasing the fan diameter. This, for example, reduces the
differences between the specific noise level and the fan efficiency
at an operating point in an operation at the highest air flow rate
and the smallest specific noise level and the highest fan
efficiency, respectively. Thus, input to the fan and noise can be
reduced.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a diagram illustrating an outline of an
air-sending device according to Embodiment 1 of the present
invention.
[0012] FIG. 2 is a graph illustrating a P-Q characteristic and a
Ks-Q characteristic of a propeller fan 1 alone.
[0013] FIG. 3 is a graph illustrating the P-Q characteristic and an
.eta.-Q characteristic of the propeller fan 1 alone.
[0014] FIG. 4 is a graph illustrating relationships of the P-Q
characteristic and the Ks-Q characteristic with respect to the
diameter.
[0015] FIG. 5 is a graph illustrating relationships of the P-Q
characteristic and the .eta.-Q characteristic with respect to the
diameter.
[0016] FIG. 6 is a diagram illustrating exemplary dimensional
parameters related to a bellmouth 2.
[0017] FIG. 7 is a graph illustrating the P-Q characteristic based
on the dimensional parameters.
[0018] FIG. 8 is a graph illustrating the P-Q characteristic
observed when L/L0 is varied.
[0019] FIG. 9 is a graph illustrating a relationship between
specific noise level Ks and the value of L/L0 at an air flow rate
Q2.
[0020] FIG. 10 is a graph illustrating the P-Q characteristic
observed when a sloping-portion angle .theta. is varied.
[0021] FIG. 11 is a graph illustrating relationships of fan
efficiency .eta. and the specific noise level Ks with respect to
the angle .theta. at the air flow rate Q2.
[0022] FIG. 12 is a graph illustrating the P-Q characteristic
observed when the value of H/D is varied.
[0023] FIG. 13 is a graph illustrating a relationship between
static pressure P and the value of H/D at the air flow rate Q2.
[0024] FIG. 14 is a graph illustrating relationships of the fan
efficiency .eta. and the specific noise level Ks with respect to
the H/D at the air flow rate Q2.
[0025] FIG. 15 is a perspective view of a bellmouth 2 having
another shape.
[0026] FIG. 16 includes diagrams illustrating sloping portions 5a
having other exemplary shapes.
[0027] FIG. 17 includes diagrams illustrating configurations of
top-blowing outdoor units.
[0028] FIG. 18 is a diagram illustrating a configuration of a
side-blowing outdoor unit.
[0029] FIG. 19 is an exploded perspective view of a side-blowing
bellmouth.
[0030] FIG. 20 is a diagram illustrating a relationship between the
shape of the bellmouth 2 and the flow of air.
[0031] FIG. 21 is a diagram illustrating a shape of the bellmouth 2
according to Embodiment 2 and the flow of air.
[0032] FIG. 22 is a diagram illustrating a relationship between the
bellmouth 2 and a fan guard.
[0033] FIG. 23 is a graph illustrating relationships of input to
the fan and noise with respect to an angle .alpha..
[0034] FIG. 24 is a diagram illustrating a propeller fan 1
according to Embodiment 4.
[0035] FIG. 25 is a diagram illustrating path lines representing a
blade-tip vortex produced in a case where ribs 6 are not
provided.
[0036] FIG. 26 is a diagram illustrating path lines representing a
blade-tip vortex produced in a case where the ribs 6 are
provided.
[0037] FIG. 27 is a diagram illustrating an inlet opening 3 of the
bellmouth 2.
[0038] FIG. 28 is a graph illustrating a relationship between the
P-Q characteristic and the R/D value.
[0039] FIG. 29 is a graph illustrating a relationship between the
specific noise level Ks and the R/D value at the air flow rate
Q2.
[0040] FIG. 30 is a graph illustrating a relationship between the
fan efficiency .eta. and the R/D value at the air flow rate Q2.
[0041] FIG. 31 is a block diagram of a refrigeration and
air-conditioning apparatus according to Embodiment 6 of the present
invention.
DETAILED DESCRIPTION
Embodiment 1
[0042] FIG. 1 is a diagram illustrating an outline of an
air-sending device according to Embodiment 1 of the present
invention. FIG. 1 illustrates a propeller fan 1 and a bellmouth 2
in sectional view. The air-sending device according to Embodiment 1
is to be provided in, for example, an outdoor unit of a
refrigeration cycle apparatus such as an air-conditioning
apparatus.
[0043] The propeller fan 1 is an axial fan that produces a flow of
air (fluid) by causing a plurality of blades (a propeller, or
wings) to rotate about a rotation axis when a motor or the like
(not illustrated) is driven with power supplied thereto. The
propeller fan 1 described herein is not especially limited to but
is a fan having a forward-swept shape. Furthermore, the propeller
fan 1 (air-sending device) is disposed as a top-blowing air-sending
device in the outdoor unit such that the rotation axis thereof
substantially corresponds to the direction of gravity (vertical
direction, hereinafter also referred to as height direction of the
air-sending device) and air is thus blown in a direction opposite
to the direction of gravity.
[0044] The bellmouth 2 covers the propeller fan 1 in such a manner
as to extend in the circumferential direction (direction of
rotation) of the propeller fan 1 (the bellmouth 2 surrounds the
propeller fan 1) and is configured to rectify the flow of air
produced by the rotation of the propeller fan 1. That is, a tubular
wall is provided around the propeller fan 1. As illustrated in FIG.
1, the bellmouth 2 according to Embodiment 1 covers about 50% of
the propeller fan 1 in the direction of the rotation axis (height
direction) of the propeller fan 1.
[0045] An inlet opening 3 is open on the upstream side (inlet side)
of the bellmouth 2 so that air is taken in therefrom. In the
bellmouth 2 according to Embodiment 1, the distance between the
rotation axis of the propeller fan 1 and the end of the inlet
opening 3 (the radius of the opening) is larger than the distance
between the rotation axis and the surface of a straight tubular
portion 4 (the radius of the straight tubular portion 4) (the end
of the inlet opening 3 spreads outward). Furthermore, an inner wall
(a surface facing the propeller fan 1) extending from the
inlet-side end of the straight tubular portion 4 to the end of the
inlet opening 3 forms a curved surface (with an arc sectional
shape). The curved surface has a radius of curvature R. A portion
of the inlet opening 3 having the curved surface is referred to as
radius corner 3a.
[0046] The straight tubular portion 4 is a portion of the bellmouth
2 where the inner wall of the bellmouth 2 extends parallel to the
rotation axis of the propeller fan 1. The position of the
outlet-side end of the straight tubular portion 4 and the
outlet-side position of the blades of the propeller fan 1 are not
especially limited to but substantially coincide with each other in
the height direction of the air-sending device.
[0047] An outlet opening 5 is open on the downstream side (outlet
side) of the bellmouth 2 so that air is blown therefrom. Regarding
the outlet opening 5 also, the distance between the rotation axis
of the propeller fan 1 and the end of the outlet opening 5 (the
radius of the opening) is larger than the distance between the
rotation axis and the surface of the straight tubular portion 4
(the radius of the straight tubular portion 4). Furthermore, an
inner wall extending from the outlet-side end of the straight
tubular portion 4 (the inlet-side end of the outlet opening 5) to
the outlet-side end of the outlet opening 5 forms a sloping surface
that spreads outward with a tapered (flared) sectional shape. The
tapered portion is referred to as a sloping portion 5a. Although
the inner wall of the bellmouth 2 according to Embodiment 1 may be
formed merely with the sloping portion 5a and the radius corner
3a.
[0048] FIG. 2 is a graph illustrating a P-Q characteristic and a
Ks-Q characteristic of the propeller fan 1 alone. FIG. 3 is a graph
illustrating the P-Q characteristic and an .eta.-Q characteristic
of the propeller fan 1 alone. Here, P denotes static pressure, Q
denotes air flow rate, Ks denotes specific noise level [dB], and
.eta. denotes fan efficiency (static-pressure efficiency) [%].
Given the static pressure P and the air flow rate Q, the specific
noise level Ks and the fan efficiency .eta. satisfy the below
Equations (1) and (2), respectively, where SPL denotes noise [dB]
at a position away from the propeller fan 1 by a predetermined
distance, T denotes torque [Nm], and .omega. denotes angular
velocity [rad/s]. In Equation (1), the unit of static pressure P1
is [mmAq], and the unit of air flow rate Q1 is [m.sup.3/min]. In
Equation (2), the unit of static pressure P2 is [Pa], and the unit
of air flow rate Q2 is [m.sup.3/s].
Ks=SPL-10 log 10(P1Q1.sup.2.5) (1)
.eta.=100.times.P2Q2/T.omega. (2)
[0049] Referring to FIGS. 2 and 3, relationships among the static
pressure P, the air flow rate Q, the specific noise level Ks, and
the fan efficiency .eta. will be described. The P-Q characteristic
represents a relationship between the static pressure P, which is
airflow resistance, and the air flow rate Q, supposing that the fan
rotation speed of the propeller fan 1 is constant. Hereinafter, a
side having low air flow rate and high static pressure is referred
to as closed side, and a side having high air flow rate and low
static pressure is referred to as open side. In general, air flows
more easily as the airflow resistance becomes smaller (the air flow
rate Q becomes higher as the static pressure P becomes lower),
whereas air flows more difficulty as the airflow resistance becomes
larger (the air flow rate Q becomes lower as the static pressure P
becomes higher).
[0050] However, the air flow rate Q and the static pressure P do
not always have such a relationship. There is a zone in which the
variation in static pressure P with respect to the air flow rate Q
is small. This zone is referred to as a surging zone. During
rotation of any propeller fan 1, the specific noise level Ks
becomes smallest and the fan efficiency .eta. becomes highest
around the surging zone.
[0051] FIG. 4 is a graph illustrating relationships of the P-Q
characteristic and the Ks-Q characteristic with respect to the fan
diameter (fan rotation diameter) of the propeller fan 1. FIG. 5 is
a graph illustrating relationships of the P-Q characteristic and
the .eta.-Q characteristic with respect to the diameter of the
propeller fan 1. As illustrated in FIGS. 4 and 5, when the fan
diameter is increased, the surging zone shifts toward the open
side. Furthermore, when the fan diameter is increased, the gradient
of the P-Q characteristic becomes gentler in a zone on the open
side with respect to the surging zone. In contrast, when the fan
diameter is reduced, the gradient of the P-Q characteristic becomes
steeper in the zone on the open side with respect to the surging
zone.
[0052] Now, an operating point will be described. In an outdoor
unit of an air-conditioning apparatus including the propeller fan 1
(air-sending device), let the fan rotation speed of the propeller
fan 1 at a predetermined air flow rate Q0 be N0 while a static
pressure P0 at the air flow rate Q0 is calculated from the P-Q
characteristic of the propeller fan 1 alone obtained at the fan
rotation speed N0, then, (P0, Q0) is defined as the operating
point.
[0053] In a case in which the operating point of the air-sending
device is on the open side with respect to the surging zone, the
specific noise level Ks at the operating point is larger than the
specific noise level at a point where specific noise level is
smallest and the fan efficiency .eta. at the operating point is
lower than the fan efficiency at a point where fan efficiency is
highest. In this case, when the fan diameter is increased, the
surging zone shifts toward the open side, as described above, and
closer to the operating point. Therefore, the specific noise level
Ks and the fan efficiency .eta. at the operating point become
closer to the specific noise level at the point where specific
noise level is smallest and to the fan efficiency at the point
where fan efficiency is highest, respectively. Hence, noise and
input (power supply) to the fan can be reduced.
[0054] However, if the fan diameter is increased, the size of the
air-sending device increases and hence the size of an apparatus in
which the air-sending device is to be provided needs to be
increased. The increase in size leads to problems such as increase
in cost, deterioration in design, increase in installation space,
and so forth.
[0055] To make the specific noise level Ks and the fan efficiency
.eta. at the operating point become closer to the smallest specific
noise level and the highest fan efficiency in a case where the fan
diameter cannot be increased and the operating point is on the open
side with respect to the surging zone, the gradient of the P-Q
characteristic may be made gentler in a zone on the open side with
respect to the surging zone so that the static pressure on the open
side becomes higher. In such a case, the gradients of the Ks-Q
characteristic and the .eta.-Q characteristic also become gentler,
and the deviations of the specific noise level Ks and the fan
efficiency .eta. at the operating point from the specific noise
level at the point where specific noise level is smallest and the
fan efficiency at the point where fan efficiency is highest become
smaller than those in a case where the foregoing gradients are
steep. Therefore, noise and input to the fan can be reduced. In the
case where the gradients of the Ks-Q characteristic and the .eta.-Q
characteristic are gentle, even if the operating point is shifted
by, for example, changing the setting of the air flow rate in the
air-sending device, the variations in the specific noise level Ks
and in the fan efficiency .eta. can be suppressed to be small.
Therefore, an efficient operation is achieved. In such a case, the
smallest specific noise level and the highest fan efficiency are
determined dominantly by the fan diameter. The larger the fan
diameter, the smaller the smallest specific noise level and the
higher the highest fan efficiency. The smaller the fan diameter,
the larger the smallest specific noise level and the lower the
highest fan efficiency. Furthermore, the larger the fan diameter,
the gentler the gradient of the P-Q characteristic. The smaller the
fan diameter, the steeper the gradient of the P-Q
characteristic.
[0056] For example, in an air-conditioning apparatus including a
propeller fan 1, there are ones in which the setting of the air
flow rate is changed among a plurality of levels. In the case where
the fan diameter cannot be increased, during an operation at the
highest air flow rate, the operating points for the Ks-Q
characteristic and for the .eta.-Q characteristic deviate from the
point where specific noise level is smallest and the point where
fan efficiency is highest, respectively. Consequently, noise and
input to the fan tend to increase. This is because of the following
reason. As described above, in the case where the fan diameter
cannot be increased sufficiently, the surging zone is on the closed
side while the operating point in the operation at the highest air
flow rate is on the open side.
[0057] FIG. 6 is a diagram illustrating exemplary dimensional
parameters related to the bellmouth 2. As illustrated in FIG. 6,
the diameter of the propeller fan 1 (fan diameter) is denoted by D,
the length of the bellmouth 2 in the direction of the rotation axis
from the end of the inlet opening 3 to the outlet-side end of the
straight tubular portion 4 (bellmouth height) is denoted by L, the
length of the blades in the direction of the rotation axis of the
propeller fan 1 (fan height) is denoted by L0, the lengths of the
sloping portion 5a at the outlet opening 5 in the direction of the
rotation axis of the propeller fan 1 (height, hereinafter referred
to as sloping-portion height) and in the direction of the fan
diameter D (hereinafter referred to as sloping-portion length) are
denoted by H and W, respectively, and the angle between a direction
in which the sloping portion 5a is tapered and the direction of the
rotation axis of the propeller fan 1 is denoted as sloping-portion
angle .theta..
[0058] FIG. 7 is a graph illustrating the P-Q characteristic based
on the dimensional parameters illustrated in FIG. 6, specifically,
the P-Q characteristic observed when the parameters related to the
air-sending device illustrated in FIG. 6 are set so as to satisfy
D=700 mm, L/L0=0.1, H/D=0.01, and .theta.=45.degree., with the fan
rotation speed set to NA. In FIG. 7, the air flow rate Q1
corresponds to the air flow rate around the surging zone, and the
air flow rate Q2 corresponds to the air flow rate at the operating
point that is on the open side with respect to the surging
zone.
[0059] Now, there will be described an air-sending device in which
the static pressure P at the operating point that is on the open
side with respect to the surging zone is high and the gradient of
the P-Q characteristic on the open side with respect to the surging
zone is gentle. Hereinafter, the term open side refers to an
operating point that is on the open side with respect to the
surging zone.
[0060] FIG. 8 is a graph illustrating the P-Q characteristic
observed when L/L0 is varied. In this case, L/L0 is varied by
varying the bellmouth height L with the fan height L0 being
constant. As illustrated in FIG. 8, the static pressure P is
substantially constant around the surging zone where the air flow
rate is Q1, regardless of the value of L/L0. At the operating point
where the air flow rate is Q2 that is on the open side with respect
to the air flow rate Q1, as L/L0 becomes larger, the static
pressure P becomes higher in a range of L/L0<0.5 but is
substantially constant in a range of L/L0.ltoreq.0.5.
[0061] FIG. 9 is a graph illustrating a relationship between the
specific noise level Ks [dB] and the value of L/L0 in the
air-sending device with the fan rotation speed being NA and the air
flow rate being Q2. As illustrated in FIG. 9, in the range of
L/L0<0.5, the specific noise level Ks on the open side can be
reduced more as the value of L/L0 becomes larger. Meanwhile, in the
range of L/L0.gtoreq.0.5, the specific noise level Ks on the open
side does not substantially change.
[0062] The reason for this is as follows. In a case where the
bellmouth height L is small, a blade-tip vortex tends to occur from
portions of the blades of the propeller fan 1 that are not covered
by the bellmouth 2, generating noise. In contrast, in a case where
the bellmouth height L is large, the flow path for the blade-tip
vortex is narrowed. Therefore, noise due to the blade-tip vortex is
reduced, whereas variations in the static pressure on the wall of
the bellmouth 2 facing the fan increase. Hence, in the range of
L/L0<0.5, noise due to the blade-tip vortex is reduced more as
the bellmouth height L becomes larger. In the range of
L/L0.gtoreq.0.5, the influences of the two are of substantially the
same level and do not substantially vary. Accordingly, the specific
noise level Ks does not vary. Considering the above, the propeller
fan 1 and the bellmouth 2 desirably satisfy a relationship of
L/L0.gtoreq.0.5 in the height direction.
[0063] Now, there will be described a case where the
sloping-portion angle .theta. is varied while the parameters
illustrated in FIG. 6 are set so as to satisfy L/L0=0.5 and
W/D=0.15. In this case, H=W/tan .theta.. To distinguish this case
from a case where W=0 and the fan diameter D is large, the
sloping-portion length W is set so as to be constant.
[0064] FIG. 10 is a graph illustrating the P-Q characteristic
observed when the sloping-portion angle .theta. is varied with the
fan rotation speed being NA. The static pressure P is substantially
constant around the surging zone, regardless of the sloping-portion
angle .theta.. In contrast, in a range of
.theta..gtoreq.60.degree., the static pressure P on the open side
with respect to the surging zone becomes smaller as the
sloping-portion angle .theta. becomes larger. In a range of
0<.theta..gtoreq.60.degree., the static pressure P on the open
side is substantially constant.
[0065] FIG. 11 is a graph illustrating relationships of the fan
efficiency .eta. and the specific noise level Ks with respect to
the angle .theta. with the fan rotation speed being NA and the air
flow rate being Q2. In FIG. 11, the fan efficiency .eta. and the
specific noise level Ks around the surging zone are substantially
constant regardless of .theta.. In the range of
.theta..gtoreq.60.degree., the fan efficiency .eta. becomes lower
and the specific noise level Ks becomes higher as .theta. becomes
larger. In the range of 0<.theta..gtoreq.60.degree., the fan
efficiency .eta. and the specific noise level Ks on the open side
are considered to be substantially constant with small rates of
increase (note that 0<.theta..gtoreq.45.degree. is considered to
be more preferable because the fan efficiency .eta. and the
specific noise level Ks slightly increase in a range between
45.degree. and 60.degree.).
[0066] The reason why the fan efficiency .eta. and the specific
noise level Ks on the open side are improved in the range of
0<.theta..gtoreq.60.degree. compared with those observed in the
range of .theta..gtoreq.60.degree. is as follows. Since the area of
an outlet air passage provided at the outlet opening 5 is
increased, the velocity at which air is blown is reduced and the
static pressure P is increased. Furthermore, since the outlet
opening 5 spreads outward, the outlet air passage functions as a
diffuser. In such a situation, in the range of
0<.theta..gtoreq.60.degree., air flowing near the sloping
portion 5a is blown along the sloping portion 5a. Thus, the
function as a diffuser is exerted.
[0067] FIG. 12 is a graph illustrating the P-Q characteristic
observed when the value of H/D is varied with the fan rotation
speed being NA. FIG. 13 is a graph illustrating a relationship
between the static pressure P and the value of H/D with the fan
rotation speed being NA and the air flow rate being Q2. In this
case, the parameters related to the air-sending device illustrated
in FIG. 6 are set so as to satisfy L/L0=0.5 and
.theta.=60.degree..
[0068] Referring to FIG. 12, the static pressure P is substantially
constant around the surging zone, regardless of the value of H/D.
In contrast, in a range of H/D<0.04, the static pressure P on
the open side with respect to the surging zone becomes larger as
the value of H/D becomes larger. In a range of H/D.gtoreq.0.04, the
static pressure P on the open side is substantially constant.
[0069] As illustrated in FIG. 13, as the value of H/D becomes
larger, the static pressure P on the open side becomes larger but
the increase in the static pressure P with respect to the value of
H/D is smaller than that in the range of H/D<0.04.
[0070] FIG. 14 is a graph illustrating relationships of the fan
efficiency .eta. and the specific noise level Ks with respect to
H/D with the fan rotation speed being NA and the air flow rate
being Q2. In FIG. 14, the fan efficiency .eta. and the specific
noise level Ks around the surging zone are substantially constant
regardless of the value of H/D. In contrast, in the range of
H/D<0.04, the fan efficiency .eta. becomes lower and the
specific noise level Ks becomes larger as the value of H/D becomes
smaller. In the range of H/D.gtoreq.0.04, the improvements in the
fan efficiency .eta. and in the specific noise level Ks on the open
side become smaller relative to the increase in the value of
H/D.
[0071] The reason why the fan efficiency and the specific noise
level on the open side are more improved in the range of
H/D.gtoreq.0.04 than in the range of H/D<0.04 is as follows.
Since the area of the outlet air passage is increased, the velocity
at which air is blown is reduced and the static pressure P is
increased. Furthermore, since the outlet opening 5 spreads outward,
the outlet air passage functions as a diffuser. In such a
situation, in the range of H/D.gtoreq.0.04, the function as a
diffuser is exerted efficiently.
[0072] As described above, when the fan diameter D is small, the
surging zone is shifted toward the closed side. Therefore, a
certain size of the fan diameter D needs to be provided (for
example, in an outdoor unit, the fan diameter D is desired to be
600 mm or larger). Hence, when it is attempted to increase the
value of H/D, the sloping-portion height H is to be increased. This
accompanies an increase in the size of a downstream portion of the
bellmouth 2.
[0073] As illustrated in FIG. 14, for example, in the range of
H/D.gtoreq.0.04, the improvements in the fan efficiency .eta. and
in the specific noise level Ks on the open side are relatively
small even if the value of H/D is increased. Therefore, in the
range of H/D.gtoreq.0.04, H/D is set to a large value if, for
example, there is any allowance for the range of possible size of
the bellmouth 2 in relation to the casing of a heat source unit. If
there is no such allowance, at least H/D=0.04 is to be satisfied.
Thus, the fan efficiency .eta. and the specific noise level Ks on
the open side can be improved.
[0074] In the air-sending device according to Embodiment 1 that is
to be provided in an outdoor unit, the propeller fan 1 and the
bellmouth 2 are configured such that conditions (parameters) are
set so as to satisfy the relationships of H/D.gtoreq.0.04,
0<.theta.60.degree., and L/L0.gtoreq.0.5 as described above. In
addition, as demonstrated by the above results, if the air-sending
device is configured on the basis of the conditions satisfying the
above relationships, the conditions each provide an effect of
suppressing the increase in noise and power consumption (input to
the fan). For example, one of the conditions for suppressing the
increase in noise and power consumption that provides the most
significant effect is the condition satisfying H/D.gtoreq.0.04,
followed by the condition satisfying 0<.theta..gtoreq.60.degree.
and the condition satisfying L/L0.gtoreq.0.5, sequentially.
Therefore, even if not all of the conditions are satisfied, one of
or a combination of any of the conditions only needs to be
satisfied, whereby the effects according to the present invention
are provided.
[0075] FIG. 15 is a perspective view of a bellmouth 2 having
another shape. For example, if the diameter of the bellmouth 2
(particularly, the outlet opening 5) is larger than at least one of
the width and the depth of the casing of an outdoor unit, the
bellmouth 2 extends beyond the casing and comes into contact with
another bellmouth provided in another outdoor unit. This may make
it difficult to arrange a plurality of outdoor units close to one
another. Hence, the shape of the bellmouth 2 may be partially
altered such that the diameter thereof becomes smaller than the
width and the depth of the casing of the outdoor unit. For example,
in the bellmouth 2 illustrated in FIG. 16, the sloping-portion
angle .theta. is not constant over the entire circumference of the
bellmouth 2 and is changed in some portions. Thus, the bellmouth 2
is prevented from extending beyond the casing while the
above-described conditions are satisfied.
[0076] FIG. 16 includes diagrams illustrating sloping portions 5a
having other exemplary shapes, respectively. For example, in FIG. 1
and others, the sloping portion 5a extends linearly in sectional
view. In some cases, however, the sloping portion 5a may not be
able to extend linearly because of restrictions on the
manufacturing process, design, dimensions, and so forth. Even in
such a case, an effect similar to that provided by the sloping
portion 5a that extends linearly can be provided, as long as the
angle of a straight line connecting the two ends of the sloping
portion 5a falls within a range of about
0<.theta..gtoreq.60.degree.. For example, the sloping portion 5a
may have a concave, substantially arc shape as illustrated in FIG.
16(a), a convex, substantially arc shape as illustrated in FIG.
16(b), or the like.
[0077] FIG. 17 includes diagrams illustrating configurations of
top-blowing outdoor units, respectively. FIG. 17(a) illustrates an
outdoor unit in which an outdoor-side heat exchanger that exchanges
heat between a refrigerant and air has a rectangular U shape in a
casing. FIG. 17(b) illustrates an outdoor unit in which an
outdoor-side heat exchanger has a V shape, or a W shape. As
illustrated in FIG. 17, in a top-blowing outdoor unit, the heat
exchanger has a rectangular U, V, or W shape with a plurality of
bends, and the air-sending device blows air in the direction
opposite to the direction of gravity (in a top-blowing
direction).
[0078] FIG. 18 is a diagram illustrating a configuration of a
side-blowing outdoor unit. As illustrated in FIG. 18, an
air-sending device provided in the side-blowing outdoor unit blows
air in a direction perpendicular to the direction of gravity. The
side-blowing outdoor unit includes an outdoor-side heat exchanger
having an L shape.
[0079] Comparing the rectangular-U-shaped heat exchanger for the
top-blowing type illustrated in FIG. 17(a) and an L-shaped heat
exchanger for the side-blowing type, the rectangular-U-shaped heat
exchanger takes in air from three sides, whereas the L-shaped heat
exchanger takes in air from two sides. Therefore, the
rectangular-U-shaped heat exchanger can have a certain level of
capacity more easily than the L-shaped heat exchanger.
[0080] In the top-blowing type with a plurality of bends
illustrated in FIG. 17(b), a portion of the heat exchanger
allocated to one propeller fan (air-sending device) has a V shape.
In this case, air is taken in from two sides, as with the L-shaped
heat exchanger. Furthermore, the two heat exchangers have the same
length. In contrast, in the L-shaped heat exchanger for the
side-blowing outdoor unit, one side of the heat exchanger as the
inlet side is short. Therefore, the V-shaped heat exchanger
provided in the top-blowing outdoor unit can have a certain level
of capacity more easily than the L-shaped heat exchanger. Hence,
the area of the front surface of the heat exchanger increases, and
the front velocity through the heat exchanger is reduced.
Accordingly, the airflow resistance of the heat exchanger is
reduced. Thus, the airflow resistance of the outdoor unit as a
whole can be reduced.
[0081] Hereinafter, a loss factor .xi. is used as an index that
indicates on which of the closed side and the open side the
operating point is. Letting the static pressure and the air flow
rate at the operating point be P and Q, respectively, the loss
factor .xi. is expressed as .xi.=P/Q.sup.2. As .xi. becomes
smaller, the operating point is shifted more toward the open side.
As .xi. becomes larger, the operating point is shifted more toward
the closed side.
[0082] The heat exchanger of the top-blowing outdoor unit, which in
general has smaller airflow resistance than that of the
side-blowing outdoor unit as described above, has a smaller loss
factor .xi. with the operating point being on the open side.
Therefore, to bring the surging zone closer to the operating point,
the top-blowing type needs to have a larger fan diameter D than the
side-blowing type. If the fan diameter D cannot be increased
because of any design restrictions, such as installation area, on
the size of the outdoor unit, the operating point is defined on the
open side with respect to the surging zone. Consequently, the
specific noise level Ks is increased and the fan efficiency .eta.
is reduced.
[0083] In view of the above, the configuration according to the
present invention defined so as to bring the operating point closer
to the surging zone without increasing the fan diameter D is more
necessary for the top-blowing outdoor unit than for the
side-blowing outdoor unit and can exert its effects more in the
top-blowing outdoor unit.
[0084] Now, differences between a bellmouth for the top-blowing
type and a bellmouth for the side-blowing type will be described.
As an exemplary bellmouth for the top-blowing type, the bellmouth 2
shaped as illustrated in FIG. 15 is made of resin and can be formed
by solid casting, regardless of L/L0 illustrated in FIG. 1.
[0085] FIG. 19 is an exploded perspective view of the side-blowing
bellmouth. In general, a bellmouth sheet metal 10 illustrated in
FIG. 19 is formed into a bellmouth for a side-blowing outdoor unit
by solid casting. In such a case, L/L0 of the bellmouth 2 cannot be
made large (L/L0=1, for example). To do so, other parts need to be
prepared.
[0086] Hence, to apply the bellmouth shape according to the present
invention to a side-blowing outdoor unit is relatively more
difficult than to apply it to a top-blowing outdoor unit and is not
practical.
[0087] As described above, according to Embodiment 1, the
air-sending device of the outdoor unit is configured under the
conditions of L/L0.gtoreq.0.5, 0<.theta..gtoreq.60.degree., and
H/D.gtoreq.0.04. Therefore, the relationship between the static
pressure P and the air flow rate Q on the open side can be made
closer to the relationship between the static pressure P and the
air flow rate Q in the surging zone without increasing the fan
diameter D, and hence the fan efficiency .eta. and the specific
noise level Ks can be improved. Thus, input to the fan and noise
can be reduced.
Embodiment 2
[0088] FIG. 20 is a diagram illustrating a relationship between the
shape of the bellmouth 2 and the flow of air. In FIG. 20,
individual airflows are represented by streamlines. On the
downstream side of the bellmouth, air blown from the outlet opening
5 flows more obliquely along the sloping portion 5a as the distance
to the wall of the sloping portion 5a becomes smaller. For example,
in a case where an air-conditioning apparatus includes a plurality
of outdoor units that are provided on the rooftop of a building,
short cycles may occur in which air that have been blown obliquely
is taken into adjacent outdoor units because of the suction force
of propeller fans 1 of the adjacent outdoor units and ambient wind.
For example, in an outdoor unit that has taken in high-temperature
air blown from another outdoor unit including an outdoor-side heat
exchanger functioning as a condenser in a casing, the temperature
difference between the refrigerant and air is reduced. This may
reduce the efficiency of heat exchange and hence COP.
[0089] FIG. 21 is a diagram illustrating a shape of the bellmouth 2
according to Embodiment 2 and the flow of air. The bellmouth 2
according to Embodiment 2 illustrated in FIG. 21 includes a
straight tubular portion 5b provided at the downstream exit (end)
of the outlet opening 5. Suppose that the sloping portion 5a
satisfies the conditions (parameters) that are set as described in
Embodiment 1.
[0090] Under such circumstances, air around the outer circumference
of a downstream portion of the bellmouth 2 flows along the sloping
portion 5a and the straight tubular portion 5b and is blown upward
(the direction opposite to the direction of gravity). Therefore,
the occurrence of short cycles into adjacent outdoor units can be
suppressed.
[0091] Furthermore, for example, to protect the propeller fan 1 and
other members from foreign matter that may be taken into the outlet
opening 5, a fan guard in the form of a grating that covers the
outlet opening 5 may be provided. In such a case, the fan guard can
be easily fixed by providing a straight tubular portion 5b at the
downstream end of the bellmouth.
[0092] As described above, in the outdoor unit including the
air-sending device according to Embodiment 2, the straight tubular
portion 5b is provided at the downstream exit (end) of the outlet
opening 5 and allows air to be blown upward so that adjacent
outdoor units are not affected. Thus, the occurrence of short
cycles can be suppressed. Furthermore, the fan guard in the form of
a grating can be easily fixed.
Embodiment 3
[0093] FIG. 22 is a diagram illustrating a relationship between the
bellmouth 2 of an air-sending device and a fan guard 10 provided to
the air-sending device. In FIG. 22, the fan guard is a grating-like
net and covers the outlet opening 5, thereby protecting the
propeller fan 1 and other devices provided in the casing of the
outdoor unit. The grating has a certain length in the height
direction. Therefore, some air collides on side surfaces depending
on the angle of airflow. In this case, the angle between the
grating of the fan guard and the rotation axis of the fan is
denoted by .alpha..
[0094] FIG. 23 is a graph illustrating relationships of the input
to the fan and the noise with respect to the angle .alpha. in a
case where, for example, air is blown from the outdoor unit at a
predetermined rate. As illustrated in FIG. 23, when
.alpha.=0.degree., the input to the fan and the noise are both
smallest. This is because the airflow resistance at the grating of
the fan guard becomes smallest when .alpha.=0.degree.. Considering
such circumstances, the grating of the fan guard is preferably
configured such that the angle thereof with respect to the rotation
axis of the fan becomes as close to 0.degree. as possible.
[0095] As described above, in the outdoor unit including the
air-sending device according to Embodiment 3, air resistance can be
minimized by setting the angle between the grating of the fan guard
and the rotation axis of the fan to 0.degree.. Therefore, input to
the fan required and noise generated when air is blown from the
outdoor unit at a predetermined air flow rate can be minimized, and
the outdoor unit can have high operation and energy efficiency.
Embodiment 4
[0096] FIG. 24 is a diagram illustrating a propeller fan 1
according to Embodiment 4. In Embodiment 4, a shape of the
propeller fan 1 will be described. The propeller fan 1 according to
Embodiment 4 has ribs 6 extending from the outer peripheral edge of
a suction surface of the propeller fan 1 toward the upstream side
in the axial direction.
[0097] Table 1 summarizes values of the input to the fan and the
noise at a predetermined air flow rate for an air-sending device
including the propeller fan 1 having the ribs 6 and an air-sending
device including the propeller fan 1 not having the ribs 6.
TABLE-US-00001 TABLE 1 Input to fan [W] Noise [dB] Without ribs 6
632 62.1 With ribs 6 630 60.8
[0098] Table 1 shows that the values of the input to the fan are
substantially the same, whereas the noise for the case where the
ribs 6 are provided is smaller. The reason for this is as follows.
First, the rms of variations in the static pressure on the wall of
the straight tubular portion 4 of the bellmouth 2 is defined on the
basis of a static pressure Ps(t) in accordance with Equations (3)
and (4) given below. The larger the rms of variations in the static
pressure, the larger the noise generated from the wall.
[Math. 1]
p.sub.s(t)= p.sub.s+p.sub.s'(t) (3) [0099] ( p.sub.s: average,
p.sub.s'(t): variation)
[0099] rms of variations in static
pressure={(Psi(t).sup.2)/N}.sup.0.5 (4) [0100] (i=1, 2, . . . ,
N)
[0101] With the increase in the vorticity of the blade-tip vortex,
which is a leakage flow occurring because of a difference in static
pressure near the outer peripheral edge of the propeller fan 1 and
from the pressure surface to the suction surface, the rms of
variations in the static pressure increases, generating noise. The
ribs 6 act as airflow resistances for the leakage flow in the form
of a blade-tip vortex occurring from the pressure surface to the
suction surface and hence narrow the flow path for the leakage
flow. Therefore, the occurrence of a blade-tip vortex can be
suppressed.
[0102] FIG. 25 is a diagram illustrating path lines representing a
blade-tip vortex produced by the rotation of the propeller fan 1
not having the ribs 6. FIG. 26 is a diagram illustrating path lines
representing a blade-tip vortex produced in the case where the ribs
6 are provided. Table 2 summarizes values of the rms of variations
in the static pressure in the cases where the ribs 6 are provided
and not provided.
TABLE-US-00002 TABLE 2 rms [Pa] Without ribs 6 118.0 With ribs 6
94.4
[0103] As illustrated in FIG. 26, in the case where the ribs 6 are
provided, the vorticity of the blade-tip vortex is smaller than
that in the case where the ribs 6 are not provided. Therefore, in
the air-sending device of the outdoor unit according to Embodiment
4, the rms of variations in the static pressure on the wall of the
bellmouth 2 is reduced as shown in Table 2. Accordingly, noise can
be reduced.
Embodiment 5
[0104] FIG. 27 is a diagram illustrating the radius of curvature R
at the radius corner 3a of the inlet opening 3 of the bellmouth 2
according to Embodiment 5. In FIG. 27, two shapes of the inlet
opening 3 having different radii of curvature R are
illustrated.
[0105] FIG. 28 is a graph illustrating a relationship between the
P-Q characteristic and R/D. The graph is based on values of R/D
(hereinafter referred to as R/D) obtained when the radius of
curvature R at the radius corner 3a is varied while the fan
diameter D and the rotation speed N0 are set so as to be constant
and the position of the end of the inlet opening 3 of the bellmouth
2 is fixed. In FIG. 28, the P-Q characteristic is represented as
R/D at each of the air flow rates Q1 and Q2.
[0106] As illustrated in FIG. 28, the static pressure P does not
significantly vary at the air flow rate Q1 regardless of R/D.
Although not especially illustrated, the specific noise level Ks
and the fan efficiency .eta. at Q1 do not significantly vary,
either, despite the variations in R/D.
[0107] FIG. 29 is a graph illustrating a relationship between the
specific noise level Ks and R/D at the air flow rate Q2. FIG. 30 is
a graph illustrating a relationship between the fan efficiency
.eta. and R/D at the air flow rate Q2. As illustrated in FIGS. 28
to 30, at the air flow rate Q2, as R/D is increased, the static
pressure P and the fan efficiency .eta. become higher and the
specific noise level Ks becomes smaller. Furthermore, the gradients
of the P-Q characteristic, the Ks-Q characteristic, and the .eta.-Q
characteristic on the open side become gentler. That is, in the
bellmouth 2, the more the radius of curvature R at the radius
corner 3a is increased, the more the static pressure P and the fan
efficiency .eta. at the operating point that is on the open side
are improved and the more the specific noise level Ks at the
operating point that is on the open side is reduced. Thus, rotation
speed, input to the fan, and noise can be reduced.
[0108] As described above, the larger the radius of curvature R at
the radius corner 3a of the inlet opening 3, the higher the fan
efficiency .eta. and the smaller the specific noise level Ks.
However, for example, if the radius of curvature R at the radius
corner 3a are to be made uniform over the entire circumference in a
case where the casing has a width and a depth (longitudinal side
and lateral side) that are of different lengths (sizes) because of
restrictions on the dimensions of the outdoor unit and so forth,
the radius of curvature R generally becomes small.
[0109] Hence, if the ratios of the longitudinal length and the
lateral length of the casing of the outdoor unit are different, any
part of the radius corner 3a that can be widened may be widened
such that there are variations in the position of the end of the
inlet opening 3 so that the integrated value of radii of curvature
R at the radius corner 3a obtained over the entire circumference of
the inlet opening 3 becomes largest.
Embodiment 6
[0110] FIG. 31 is a block diagram of a refrigeration and
air-conditioning apparatus according to Embodiment 6 of the present
invention. Embodiment 6 concerns a refrigeration and
air-conditioning apparatus as an exemplary refrigeration cycle
apparatus including the above-described air-sending device. The
refrigeration and air-conditioning apparatus illustrated in FIG. 31
includes an outdoor unit (outdoor device) 100, which is the one
described above, and a load unit (indoor device) 200 that are
connected by refrigerant pipes, thereby forming a refrigerant
circuit as a main part (hereinafter referred to as main refrigerant
circuit) through which a refrigerant is made to circulate. One of
the refrigerant pipes through which a refrigerant in a gas state
(gas refrigerant) flows is referred to as gas pipe 300. Another of
the refrigerant pipes through which a refrigerant in a liquid state
(liquid refrigerant or, occasionally, two-phase gas-liquid
refrigerant) flows is referred to as liquid pipe 400.
[0111] The outdoor unit 100 according to Embodiment 6 includes the
following devices (means): a compressor 101, an oil extractor 102,
a four-way valve 103, an outdoor-side heat exchanger 104, an
outdoor-side air-sending device 105, an accumulator (gas-liquid
separator) 106, an outdoor-side throttle device (expansion valve)
107, a heat exchanger 108 related to a refrigerant, a bypass
throttle device 109, and an outdoor-side controller 110.
[0112] The compressor 101 compresses a refrigerant sucked thereinto
and discharges the refrigerant. The compressor 101 includes an
inverter device or the like and is capable of finely changing the
capacity of the compressor 101 (the amount of the refrigerant to be
discharged per unit time) by arbitrarily changing the operating
frequency.
[0113] The oil extractor 102 extracts lubricant contained in the
refrigerant that has been discharged from the compressor 101. The
lubricant thus extracted is returned to the compressor 101. The
four-way valve 103 switches the flow of the refrigerant between
that for a cooling operation and that for a heating operation on
the basis of instructions issued by the outdoor-side controller
110. The outdoor-side heat exchanger 104 exchanges heat between a
refrigerant and air (outdoor air). For example, in the heating
operation, the outdoor-side heat exchanger 104 functions as an
evaporator and exchanges heat between the refrigerant having flowed
thereinto via the outdoor-side throttle device 107 and thus having
a low pressure and air, thereby evaporating and gasifying the
refrigerant. In the cooling operation, the outdoor-side heat
exchanger 104 functions as a condenser and exchanges heat between
the refrigerant having been compressed by the compressor 101 and
having flowed thereinto from the side of the four-way valve 103 and
air, thereby condensing and liquefying the refrigerant. The
outdoor-side heat exchanger 104 includes the outdoor-side
air-sending device 105, which is the air-sending device according
to any of Embodiments 1 to 4 described above, so that heat is
efficiently exchanged between the refrigerant and air. The
outdoor-side air-sending device 105 may also include an inverter
device so as to finely change the rotation speed of the propeller
fan 1 by arbitrarily changing the operating frequency of the fan
motor.
[0114] The heat exchanger 108 related to a refrigerant exchanges
heat between the refrigerant flowing through a main flow path in
the refrigerant circuit and the refrigerant having branched off
from the flow path into the bypass throttle device 109 (expansion
valve) and whose flow rate has been thus controlled. Particularly,
in a case where the refrigerant needs to be supercooled in the
cooling operation, the heat exchanger 108 related to the
refrigerant supercools the refrigerant and supplies the refrigerant
to the load unit 200. The liquid flowing therethrough via the
bypass throttle device 109 is returned to the accumulator 106 via a
bypass pipe. The accumulator 106 is means that stores, for example,
an excessive refrigerant that is in a liquid state. The
outdoor-side controller 110 includes, for example, a microcomputer
or the like. The outdoor-side controller 110 is capable of wired or
radio communication with a load-side controller 204 and controls
operations concerning the entirety of the refrigeration and
air-conditioning apparatus by controlling various means included in
the refrigeration and air-conditioning apparatus by, for example,
controlling the operating frequency of the compressor 101 while
controlling the inverter circuit on the basis of data concerning
detection performed by various detecting means (sensors) provided
in the refrigeration and air-conditioning apparatus.
[0115] The load unit 200 includes a load-side heat exchanger 201, a
load-side throttle device (expansion valve) 202, a load-side
air-sending device 203, and the load-side controller 204. The
load-side heat exchanger 201 exchanges heat between a refrigerant
and air. For example, in the heating operation, the load-side heat
exchanger 201 functions as a condenser and exchanges heat between
the refrigerant having flowed thereinto from the gas pipe 300 and
air, thereby condensing and liquefying the refrigerant (or turning
the refrigerant into two-phase gas-liquid) before discharging the
refrigerant toward the side of the liquid pipe 400. In the cooling
operation, the load-side heat exchanger 201 functions as an
evaporator and exchanges heat between the refrigerant whose
pressure has been reduced by the load-side throttle device 202 and
air, thereby evaporating and gasifying the refrigerant, while
letting the refrigerant take away the heat from the air, before
discharging the refrigerant toward the side of the gas pipe 300.
The load unit 200 includes the load-side air-sending device 203 for
adjusting the flow of air used for heat exchange. The speed of
operation of the load-side air-sending device 203 is determined on
the basis of, for example, settings made by the user. The load-side
throttle device 202 is provided for adjusting the pressure of the
refrigerant in the load-side heat exchanger 201 by changing its
opening degree.
[0116] The load-side controller 204 also includes a microcomputer
or the like and is capable of wired or radio communication with,
for example, the outdoor-side controller 110. The load-side
controller 204 controls various devices (means) included in the
load unit 200 so that, for example, indoor air comes to have a
predetermined temperature on the basis of instructions issued by
the outdoor-side controller 110, the residents, or the like.
Furthermore, the load-side controller 204 transmits signals
containing data concerning detection performed by detecting means
provided in the load unit 200.
[0117] As described above, in the refrigeration and
air-conditioning apparatus according to Embodiment 5, the
outdoor-side air-sending device 105, which is the air-sending
device described in any of Embodiments 1 to 4, is applied to the
outdoor unit 100 so that air is blown in the direction opposite to
the direction of gravity, whereby noise reduction is realized while
air flow rate is increased. Thus, the energy efficiency of the
refrigeration and air-conditioning apparatus (refrigeration cycle
apparatus) can be improved.
* * * * *