GB2299656A

GB2299656A - Outdoor unit of an air-conditioner

Info

Publication number: GB2299656A
Application number: GB9603896A
Authority: GB
Inventors: Hideaki Suzuki; Kouji Wada; Takashi Kakigi
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1995-04-03
Filing date: 1996-02-23
Publication date: 1996-10-09
Anticipated expiration: 2016-02-23
Also published as: KR960038339A; KR100189000B1; JPH08270985A; JP3361405B2; CN1100238C; CN1149117A; GB2299656B; TW367019U; GB9603896D0

Abstract

An outdoor unit of an air-conditioner comprises a rectangular housing (1) having an air-inlet port (4) in the back (1B) of the housing (1), and another air-inlet port (5) in one (1C) of the sides of the housing (1). An air-outlet port (3) is in the front (1A) of the housing (1). The housing (1) contains an outdoor heat exchanger (6) and a fan (12). The outdoor heat exchanger (6) comprises first and second heat-exchanging units (7, 8). The first heat-exchanging unit (7) is L-shaped as viewed from above, extending along the air-inlet ports (4, 5) and surrounding the fan (12). The second heat-exchanging (8) extends straight as viewed from above and is interposed between the first air-inlet port (4) and the first heat-exchanging unit (7). The outdoor heat exchanger (6) can therefore operate at a greater heat-exchanger capacity. Further, the resistance to the air passing through the outdoor heat exchanger (6) is made uniform, whereby the noise the air makes is reduced.

Description

"INDOOR UNIT OF AN AIR-CONDITIONER" This invention relates to an indoor unit of an air-conditioner, and more particularly to an outdoor heat exchanger which has an improved structure.

Generally an air conditioner comprises an indoor unit and an outdoor unit. The indoor unit is provided in the room which is to be air-conditioned. The outdoor unit is located outside the house. The indoor unit and the outdoor unit are connected by a refrigerant pipe and electric cords.

The outdoor unit is located as close as possible to the outer side of the house, so as not to hinder the traffic or activities. The outdoor unit incorporates an outdoor heat exchanger, a fan, a compressor, pipes, and a box containing electric components.

It is primarily important for an air-conditioner of this type to have its heat-exchanging efficiency increased. For the purpose of increasing the heatexchanging efficiency, the air-conditioner is designed so that the outdoor heat exchanger may have as large a heat-exchanging capacity as is possible.

FIG. 10 shows a conventional outdoor unit, in which the outdoor heat exchanger S comprises two heatexchanging units a and b. The heat-exchanging units a and b, both L-shaped as viewed from above, are arranged side by side and connected together. They are of so-called "fined-tube type," each having a number of fins and a heat-exchanging pipe. The fins are juxtaposed and spaced apart at prescribed short intervals. The heat-exchanging pipe meanders and passes through the fins.

The outdoor heat exchanger S is contained in a housing c. The housing c is a rectangular box. It has air-inlet ports d and e in the side A and the back B, respectively. It also has an air-outlet port f in the front C. Since the outdoor heat exchanger S is l-shaped as viewed from above, it opposes both airinlet ports d and e.

The housing contains a fan h, which opposes the air-outlet port f. The fan h comprises a fan motor m and a propeller fan g connected to the shaft of the motor m. When driven by the motor m, the propeller fan g takes air from the outside through the air-inlet ports d and e. Heat is thereby exchanged between the air on the one hand and the heat-exchanging units a and b on the other, and the air either heated or cooled is discharged through the air-outlet port f.

Comprised of two heat-exchanging unit a and b, the outdoor heat exchanger S has a heat-exchanging capacity twice as large as an outdoor heat exchanger which has a single heat-exchanging unit. However, this does not result in an 200% increase of the heat-exchanging efficiency, unless the flow rate of air supplied to the heat exchanger S is increased in proportion to the increase in the heat-exchanging capacity. In order to increase the flow rate of air proportionally, it is necessary to replace the motor m and fan g with larger ones or to drive the motor m and the fan g at higher speeds.

At the back A of the housing c, the air supplied by the propeller fan g flows in a large amount and at a high speed along the axis of the motor m. By contrast, at the side B of the housing c, the air flows in a small amount and at a low speed along a line perpendicular to the axis of the fan motor m. Hence, if the heat exchanger S is increased in heat-exchanging capacity, air must be supplied at the side B of the housing c at a flow rate increased in proportion to the increase in the heat-exchanging capacity of the heat exchanger S. To supply the air at the side B at such an increased flow rate, both the motor m and the propeller fan g must be replaced even larger ones or must be driven at higher speeds. If the motor m and the fan g are replaced with larger ones, the housing c will be inevitably larger.If the motor m and the fan g are driven at higher speeds, the noise they make will unavoidably increase.

FIG. 11 shows an outdoor unit having a heat exchanger Sa which has been devised to be free of the problems inherent in the outdoor heat exchanger S shown in FIG. 10. The components identical to those illustrated in FIG. 10 are designated at the same reference numerals in FIG. 11 and will not be described in detail.

As shown in FIG. 11, the second heat-exchanging unit b is L-shaped, while the first heat-exchanging unit j extends straight along the air-inlet port d made in the back A of the housing c. More specifically, the first heat-exchanging unit j extend parallel to the longer straight part of the second heat-exchanging unit b. The second heat-exchanging unit b is located upstream of the first heat-exchanging unit j, with respect to the flow of the air in the housing c.

With the outdoor heat exchanger Sa shown in FIG. 11, it is possible to increase the heat-exchanging capacity at the back A, without increasing the heat-exchanging capacity at the side B. As a result, the outdoor heat exchanger Sa can have its total heat-exchanging capacity increased. Obviously, the heat-exchanging capacity at the side B is less than in the outdoor heat exchanger S shown in FIG. 10.

Therefore, the propeller fan g can therefore have its diameter increased in inverse proportion to the heat-exchanging capacity at the side B of the housing c and can supply air at a higher flow rate. Both the heat-exchanging capacity and the air flow rate can be increased, without increasing the size of the housing c.

The outdoor unit shown in FIG. 11 is disadvantageous, nonetheless. Of the air taken into the housing c through the air-inlet port d provided in the back A, that part passing along the bent portion n of the L-shaped heat exchanger b collides with the U-shaped pipe k located downstream of the the bent portion n, generating turbulence. The turbulence results in an increase of the noise the air makes while flowing along the bend portion of the L-shaped heat exchanger b.

The present invention has been made in view of the foregoing. Its object is to provide an outdoor unit of an air-conditioner, which has an increased heat-exchanging capacity and in which the resistance to the air supplied from the resistance to the heat exchanger and either heated or cooled is made uniform, thereby to reduce the noise the air makes while flowing from the heat exchanger.

According to the invention there is provided an outdoor unit of an air-conditioner an outdoor unit of an air-conditioner, comprising: a rectangular housing having a back, two sides and a front; a first air-inlet port made in the back of the housing; a second airinlet port made in at least one of the sides of the housing; an air-outlet port made in the front of the housing; an outdoor heat exchanger provided in the housing; and a fan provided in the housing, for guiding air to the outdoor heat exchanger through the first and second air-inlet ports and discharging the air from the housing through the air-outlet port after the air has released or taken heat at the outdoor heat exchanger, wherein the outdoor heat exchanger comprises a first heat-exchanging unit which is constituted by a first part extending along the first air-inlet port and a second part extending along the second air-inlet port, and a second heat-exchanging unit which is located upstream of the first heat-exchanging unit with respect to an air stream generated by the fan, which extends along the first air-inlet port and which is interposed between the first air-inlet port and the first heatexchanging unit.

This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: FIG. 1 is a cutaway perspective view of an outdoor unit according to a first embodiment of the invention, which incorporates an outdoor heat exchanger; FIG. 2 is a sectional plan view of the outdoor unit shown in FIG. 1; FIG. 3 is a perspective view of the outdoor heat exchanger incorporated in the first embodiment; FIG. 4 is a side view showing parts of the first and second heat-exchanging units which constitute the outdoor heat exchanger incorporated in an outdoor unit according to a second embodiment of the invention; FIG. 5 is a side view showing parts of the first and second heat-exchanging units which constitute the outdoor heat exchanger incorporated in an outdoor unit according to a third embodiment of the invention;; FIG. 6 is a side view illustrating parts of the first and second heat-exchanging units which constitute the outdoor heat exchanger incorporated in an outdoor unit according to a fourth embodiment of the invention; FIG. 7 is a side view showing parts of the first and second heat-exchanging units which constitute the outdoor heat exchanger incorporated in an outdoor unit according to a fifth embodiment of the invention; FIG. 8 is a plan view showing parts of the first and second heat-exchanging units which constitute the outdoor heat exchanger incorporated in an outdoor unit according to a sixth embodiment of the invention; FIG. 9 is a plan view illustrating a part of an outdoor unit according to a seventh embodiment of the present invention; FIG. 10 is a sectional plan view of a conventional outdoor unit; and FIG. 11 is a sectional plan view of another conventional outdoor unit.

Embodiments of the present invention will be described, with reference to the accompanying drawings.

FIGS. 1 to 3 show an outdoor unit of an airconditioner which is the first embodiment of the present invention.

As shown in FIGS. 1 and 2, the outdoor unit comprises a rectangular housing 1. A bell mouth 2 is made in the front lA of the housing 1, defining an air-outlet port 3. Two air-inlet ports 4 and 5 are provided in the back 1B and one side 1C (the left side in FIG. 2), respectively. The housing 1 contains an outdoor exchanger 6.

The outdoor exchanger 6 comprises two heatexchanging units 7 and 8. The first heat-exchanging unit 7 is L-shaped, comprised of a long straight part and a short straight part. The longer straight part extends along the air-inlet port 4 made in the back 1B of the housing 1. The short straight part extends along the air-inlet port 5 made in the side 1C of the housing 1. The second heat-exchanging unit 8 is straight, extending along the air-inlet port 4 and located closer thereto than the long straight part of the first heat-exchanging unit 7.

As shown in FIG. 3, both heat-exchanging units 7 and 8 are of fined-tube type, each comprising a number of fins 9 and a heat-exchanging pipe 10. The fins are juxtaposed and spaced apart at prescribed short intervals. The heat-exchanging pipe 10 meanders, passing through the fins and having one set of straight portions and two sets of U-shaped portions. The U-shaped portions 10a of the first set project from the rightmost fin 9, and the U-shaped portions 11 of the second set project from the leftmost fin 9. A U-shaped connecting tube 10b connects the heat-exchanging pipes 10 of the first and second heat-exchanging units 7 and 8, at their right ends. That is, the heat-exchanging units 7 and 8 are connected by the tube 10b, constituting the outdoor heat exchanger 6.

As shown in FIG. 2 only, the endmost fins 9 of the second heat-exchanging unit 8 are aligned with the ends of the air-inlet port 4 provided in the back 1B of the housing 1. The rightmost fin 9 of the first heatexchanging unit 7 is aligned with the right end of the air-inlet port 4. The front end of the short straight part of the first heat-exchanging unit 7 is aligned with the front end of the air-inlet port 5 made in the side 1C. The U-shaped portions 10a and 11 of the heatexchanging pipe 10 and the U-shaped connecting tube 10b are not exposed to outside through the air-inlet ports 4 or 5. The air flowing into the housing 1 through the air-inlet ports 4 and 5 does not collide with neither the U-shaped portions 10, the U-shaped portions 11 or the U-shaped connecting tube 10b.

An outdoor fan 12 is provided between the air-outlet port 3 and the first heat-exchanging unit 7.

The fan 12 comprises a fan motor 14 and a propeller fan 15. The fan motor 14 is secured to a base 13.

The propeller fan 15 is mounted on the shaft of the motor 14, opposing the bell mouth 2 made in the front 1A of the housing 1.

When the motor 15 is driven, rotating the propeller fan 15, air is drawn into the housing 1 through the air-inlet ports 4 and 5 which are provided in the back 1B and side 1C of the housing 1. The air flows horizontally along the indoor heat exchanger 6 and discharged from the housing 1 through the air-outlet port 3 provided in the front 1A of the housing 1.

At the air-inlet port 4, the first and second heat-exchanging units 7 and 8 are located downstream and upstream, with respect to the flow of the air in the housing 1.

As seen from FIGS. 1 and 2, the housing 1 contains a partition 16. The partition 16 extends from the right end of the bell mouth 2 to the right end of the first heat-exchanging unit 7, dividing the interior of the housing 1 into two chambers. The first chamber is a heat-exchanging chamber 17 which contains the outdoor heat exchanger 6 and the outdoor fan 12. The second chamber is a air-compressing chamber 19 which contains a compressor 18.

A packed valve 20 is mounted on the side of the air-compressing chamber 19. Connected to the packed valve 20 is a refrigerant pipe. A box 21 containing electric components (e.g., an inverter, a reactor and the like) is located above the compressor 18.

How the outdoor unit 1, described above, operates will be explained. When the compressor 18 starts operating, the outdoor fan 12 also starts operating.

As a result, air is drawn into the housing 1 through both air-inlet ports 4 and 5. Heat is therefore exchanged between the air and the refrigerant flowing through the outdoor heat exchanger 6. In cooling mode, the refrigerant is condensed and then supplied into the outdoor heat exchanger 6. In heating mode, it is evaporated and then introduced into the outdoor heat exchanger 6. The air drawn into the housing 1 through the air-inlet port 4 provided in the back 1B takes or releases heat, first at the second heat-exchanging unit 8 and then at the first heat-exchanging unit 7. The air, thus heated or cooled, is discharged from the housing 1 through the air-outlet port 3. Meanwhile, the air drawn into the housing 1 through the air-inlet port 5 provided in the side 1C takes or releases heat at the first heat-exchanging unit 7 only. This is because only the short straight part of the unit 7 opposes the air-inlet port 5. The air, heated or cooled at the first heat exchanging unit 7, is discharged from the housing 1 through the air-outlet port 3.

Since the outdoor heat exchanger 6 is comprised two heat-exchanging units 7 and 8, it has a greater heat-exchanging capacity than one which is constituted by a single heat-exchanging unit.

Moreover, the heat-exchanging ability of the outdoor heat exchanger 6 increases as the amount in which which the outdoor fan 12 supplies air increases as will be explained below. As a result, the heat exchanger 6 acquires larger heat-exchanging ability than the outdoor heat exchanger S shown in FIG. 10 which has nothing but twice as large a heat-exchanging capacity as the conventional outdoor heat exchanger.

In addition, the noise the air makes while flowing from the heat exchanger 6 is less than the noise air makes while flowing from the outdoor heat exchanger Sa shown in FIG. 11.

The propeller fan 15 of the outdoor fan 12 supplies air in a large amount and at a high speed at the back 1B, where the air flows parallel to the axis of the fan motor 14. By contrast, the air flows in a large amount and at a low speed at the side 1C, where it flows at right angles to the axis of the fan motor 14.

As described above, the long straight part of the first heat-exchanging unit 7 and the second heatexchanging unit 8 are arranged, opposing the air-inlet port 4 made in the back 1B of the housing 1, and only the short straight part of the first heat-exchanging unit 7 is located, opposing the air-inlet port 5 made in the side 1C of the housing 1. That is, both heatexchanging units 7 and 8 are arranged at a position where the air flows in a large amount and at high speed, and the only a part of the first heat-exchanging unit 7 is provided at a position where the air flows in a small amount and at low speed. The outdoor heat exchanger 6 can therefore has a heat-exchanging capacity almost twice as much as that of the conventional outdoor heat exchanger. It can acquire a great heat-exchanging ability proportionate to the heat-exchanging capacity.

At the back 1B of the housing 1, where the air flows at a high speed, the heat-exchanging capacity is increased, thus increasing the resistance to air.

At the side 1C of the housing 1, where the air flows at a low speed, the heat-exchanging capacity is not increased at all, maintaining a low resistance to air.

Hence, the speed at which the air introduced into the housing 1 through the air-inlet ports 4 and 5 is supplied to the fan 15 from the heat-exchanging units 7 and 8 is made uniform. The noise made by the air flowing to the fan 15 is therefore smaller than in the conventional outdoor units in which air flows from the air-inlet ports to the fan at a varying speed.

The second heat-exchanging unit 8 has its U-shaped portions 10a and 11 not located to oppose the air-inlet port 4 provided in the back 1B of the housing 1. Nor is the U-shaped connecting tube 10b located to oppose the air-inlet port 4. Namely, the U-shaped portions 10a and 11 and the U-shaped connecting tube 10b are covered by the housing 1, not exposed to the outside.

Therefore, the air flowing into the housing 1 through the port 4 does not collide with the U-shaped portions 10a, the U-shaped portions 11, or the U-shaped connecting tube 10b. No turbulence is generated in the housing 1, and the noise made by the air flowing toward the heat exchanger 6 is small.

The outdoor unit shown in FIG. 1 to 3 may be modified in various ways, thereby providing several other embodiments of the present invention.

FIG. 4 shows the second embodiment of the present invention. As shown in FIG. 4, the heat-exchanging pipe 10pea of the first heat-exchanging unit 7 is located downstream of the heat-exchanging pipe 10Pb of the second-heat exchanging unit 8, with respect to the flow of air. The pipe 1OPa has a diameter da larger than the diameter Bdb of the pipe 10Pb (+da > dub).

Both pipes 1OPa and 10Pb meander, each having a plurality of straight portions. The straight portions of the heat-exchanging pipe 1OPa are juxtaposed at a pitch P, along a line perpendicular to the air flow.

The straight portions of the heat-exchanging pipe 10Pb are juxtaposed at exactly the same pitch P, along a line perpendicular to the air flow.

As mentioned above, the air flows slower at the side 1C than at the back 1B due to the physical properties of the propeller fan 15. Nevertheless, its speed at the side 1C is not so slow as twice as less than its speed at the back 1B. If the heat-exchanging pipe 1OPa of the first heat-exchanging unit 7 and the heat-exchanging pipe 10Pb of the second-heat exchanging unit 8 had the same diameter, and if the straight portions of the heat-exchanging pipe 1OPa were arranged in staggered fashion with respect to the straight portions of the heat-exchanging pipe 10Pb, the resistance to the air would be about twice as much.

Then, the air would flows faster at the side 1C than at the back 1B, inevitably making much noise.

One of the basic features of this invention is that the outdoor heat exchanger 6 has its heatexchanging capacity increased at only the back 1B of the housing 1, where the air flows at a high speed.

In the second embodiment shown in FIG. 4, this basic feature is preserved, and the noise made by the air can yet be small. This is because the pipe 1OPa of the first heat-exchanging unit 7 has a diameter Xda larger than the diameter fdb of the pipe 10Pb of the second heat-exchanging unit 8.

As seen from FIG. 4, those straight portions of the heat-exchanging pipes lOPa and l0Pb of both heatexchanging units 7 and 8, which are placed at the same level, are juxtaposed in the direction in which the air flows. This reduces the resistance to the air further more. Each straight portion of the heat-exchanging pipe lOPa is positioned right behind the straight portion of the heat-exchanging pipe l0Pb, which is placed at the same level. Thus, the straight portion of the pipe l0Pb seems to develop a temperature boundary, which would decrease the heat-exchanging efficiency at the straight portion of the heatexchanging pipe lOPa. However, the heat-exchanging efficiency at the straight portion of the heatexchanging pipe lOPa does not decrease, for two reasons. First, the pipe lOPa located downstream has a diameter Xda is smaller than the diameter db of the pipe l0Pb located upstream. Second, the fins 9 of both heat-exchanging units 7 and 8 are spaced apart from one another. Moreover, there is no increase in the resistance to air, which is another advantage of the second embodiment.

As mentioned above, the refrigerant is supplied to the first heat-exchanging unit 7 and hence to the second heat-exchanging unit 8 in the case where the outdoor heat exchanger 6 functions as condenser in the cooling mode. When the outdoor heat exchanger 6 operates as condenser, the refrigerant is assumes the form of over-heated gas at the entrance to the heat exchanger 6 since it has just been discharged from the compressor 18. The refrigerant gradually releases heat as it flows through the passage comprising the heatexchanging pipe 10 of the heat exchanger 6. As the refrigerant further flows through the passage, it changes into a gas-liquid phase and then into an overcooled state.

While the refrigerant remains over-heated gas or assumes a gas-liquid phase of high dryness (the gas dominating the liquid), it encounters a large pressure loss. Nonetheless, the heat-exchaning efficiency will increase without an increase in the pressure loss, since the diameter fda of the heat-exchanging pipe of the first heat-exchanging unit 7 into which the refrigerant is first introduced is relatively large as described above.

At the exit of the outdoor heat exchanger 6, the refrigerant is condensed, assuming either a gas-liquid phase or a liquid phase. To state it another way, the refrigerant is low in dryness. The refrigerant in gas-liquid phase or liquid phase loses pressure but only a little. It is therefore possible to raise the heat-exchanging efficiency of the outdoor heat exchanger 6, even if the diameter of the heatexchanging pipe is decreased. This is why the heatexchanging pipe lOPb of the second heat-exchanging unit 8, located downstream with respect to the flow of air, has a smaller diameter db than the heatexchanging pipe lOPa of the first heat-exchanging unit 7.

The outdoor heat exchanger 6 of the second embodiment, illustrated in FIG. 4, has a higher heatexchanging efficiency than its counterpart of the first embodiment shown in FIGS. 1 to 3, because the specific structures of the first and second heat-exchanging units 7 and 8 and the above-mentioned direction of supplying the refrigerant.

FIG. 5 shows the outdoor heat exchanger 6A of the third embodiment according to the invention. The heat exchanger 6A has a first heat-exchanging unit 7A and a second heat-exchanging unit 8A. As shown in FIG. 5, the heat-exchanging pipe lOPa of the first heatexchanging unit 7A is located downstream of the heat-exchanging pipe l0Pb of the second-heat exchanging unit 8A, with respect to the flow of air. The pipe lOPa has a diameter Xda larger than the diameter Bdb of the pipe l0Pb (+da > db). The straight portions of the heat-exchanging pipe lOPa of the first heatexchanging unit 7A are arranged in staggered fashion with respect to the straight portions of the heat-exchanging pipe l0Pb of the second heat-exchanging unit 8A.

Thanks to this particular positional relation between the heat-exchanging pipes lOPa and lOPb, the outdoor heat exchanger 6A imposes a lower resistance on the air than the conventional outdoor heat exchangers S and Sa illustrated in FIGS. 10 and 11, respectively.

Thus, the air, either heated or cooled, can pass through the outdoor heat exchanger 6A at a higher flow rate. This means that the outdoor heat exchanger 6A has a higher heat-exchanging efficiency than its counterparts of the outdoor heat exchangers S and Sa shown in FIGS. 10 and 11.

FIG. 6 illustrates the outdoor heat exchanger 6B of the fourth embodiment according to the invention.

The heat exchanger 6B has a first heat-exchanging unit 7B and a second heat-exchanging unit 8B. As shown in FIG. 6, the heat-exchanging pipe lOPa of the first heat-exchanging unit 7B is located downstream of the heat-exchanging pipe lOPb of the second-heat exchanging unit 8B, with respect to the flow of air. The pipe lOPa has a diameter fda larger than the diameter db of the pipe lOPb (+da > db). The straight portions of the heat-exchanging pipe lOPa are juxtaposed at a pitch PPc, along a line perpendicular to the air flow. The straight portions of the heat-exchanging pipe l0Pb are juxtaposed at a shorter pitch PPd, along a ling perpendicular to the air flow. Namely, PPc > PPd.

In the fourth embodiment, the resistance to air is higher than in the first to third embodiments, inevitably reducing the flow rate of air.

Nevertheless, the outdoor heat exchanger 6B acquires a higher heat-exchanging efficiency than its counterpart of the first to third embodiments since the heatexchanging pipe l0Pb of the second heat-exchanging unit 8B has more straight portions.

FIG. 7 shows the outdoor heat exchanger 6 of the fifth embodiment according to the invention. The heat exchanger 6 has a first heat-exchanging unit 7 and a second heat-exchanging unit 8.

More precisely, FIG. 7 is a side view of the outdoor heat exchanger 6. The heat-exchanging pipes lOPa and l0Pb of both heat-exchanging units 7 and 8 meander in the same way as in the second embodiment described above. In FIG. 7, short solid lines indicate the U-shaped portions lOa of the heat-exchanging pipes lOPa and l0Pb, long solid lines extending between the heat-exchanging units 7 and 8 denote connecting tubes lOb, and the broken lines designate the U-shaped portions 11 of the pipes lOPa and l0Pb.

When the outdoor heat exchanger 6 operates as condenser, the refrigerant is supplied downwards from the top of the first heat-exchanging unit 7 to the middle part of the meandering heat-exchanging pipe lOPa. The refrigerant is then let into the upper connecting tube lOb which is provided outside both heat-exchanging units 7 and 8. Then, it is supplied upwards through the upper connecting tube lOb to the top of the second heat-exchanging unit 8. Thereafter, the refrigerant is supplied downwards to the middle part of the meandering heat-exchanging pipe l0Pb. The refrigerant is the discharged from the second heatexchanging unit 8, at the middle part of the pipe lOPb.

The upper half of the heat-exchanging pipe lOPa, the upper connecting tube lOb and the upper half of the heat-exchanging pipe lOPb constitute a first passage P1.

In the meantime, the refrigerant is supplied downwards from the top of the middle part of the first heat-exchanging unit 7 to the lower end of the meandering heat-exchanging pipe lOPa. The refrigerant is then let into the lower connecting tube lOb which is provided outside both heat-exchanging units 7 and 8.

It is supplied upwards through the lower connecting tube lOb to the middle part of the second heatexchanging unit 8. Thereafter, the refrigerant is supplied downwards to the lower end of the meandering heat-exchanging pipe l0Pb. The refrigerant is the supplied from the second heat-exchanging unit 8, at the lower end of the pipe lOPb. The lower half of the heat-exchanging pipe lOPa, the lower connecting tube lOb and the lower half of the heat-exchanging pipe lOPb constitute a second passage P2.

In other words, the first passage P1 comprises the upper halves of the first and second heatexchanging units 7 and 8, whereas the second passage P2 comprises the lower halves of the first and second heat-exchanging units 7 and 8. The refrigerant is made to flow into both passages P1 and P2 at the same time.

If the outdoor heat exchanger 6 had only one refrigerant passage, the refrigerant passage should be very long to increase the heat-exchanging capacity.

The pressure loss would then increase due to the length of the refrigerant passage. Since the heat exchanger 6 has two separate refrigerant passages P1 and P2, the pressure loss can be reduced in the fifth embodiment.

As described above, the output ends of both refrigerant passages P1 and P2 are provided in the second heat-exchanging unit 8, and the heat-exchanging pipe l0Pb incorporated in this unit 8 have a diameter db which is smaller than the diameter Xda of the heat-exchanging pipe lOPa. This also serves to minimize the pressure loss in the fifth embodiment.

Hence, a third refrigerant passages need to be provided to connect the first passage P1 to the second passage P2.

FIG. 8 shows the outdoor heat exchanger of the sixth embodiment according to the invention. The heat exchanger has a first heat-exchanging unit 7C and a second heat-exchanging unit 8C. The sixth embodiment is characterized in that the fins 9 of the unit 7C are arranged at a pitch PPe shorter than the pitch PPf at which the fins 9 of the unit 8C (PPf > PPe).

As has been repeatedly indicated, when the propeller fan 15 is driven, the air flows faster at the back 1B of the housing 1 than at the side 1C thereof, but less than twice faster. To reduce the speed of air flow at the back 1B, two heat-exchanging pipes having the same diameter may be used in the first and second heat-exchanging units 7C and 8C. If two pipes are used, however, the resistance to air will increase by 200% and the air will flow faster at the side 1C than at the back 1B, inevitably making much noise.

In the fifth embodiment, the fins 9 of the second heat-exchanging unit 8C are arranged at a longer pitch PPf than those of the first heat-exchanging unit 7C.

The speed of air flow at the back 1B is thereby made almost equal to the speed of air flow at the side 1C.

As a result of this, the air will make no noise.

FIG. 9 illustrates the outdoor heat exchanger of the seventh embodiment according to the invention.

The heat exchanger has a first heat-exchanging unit 7D and a second heat-exchanging unit 8. The seventh embodiment is characterized in that the fins 9 of the long straight part 7e of the unit 7D and the fins 9 of the second heat-exchanging unit 8 are arranged at a pitch PPg, while the fins 9 of the short straight part 7f of the unit 7D are arranged at a shorter pitch PPh (PPg > PPh).

The second heat-exchanging unit 8 and the straight part 7e of the first heat-exchanging unit 7D extend parallel to each other, along the air-inlet port 4 made in the back 1B of the housing 1. The resistance to air therefore increases at the back 1B of the housing 1.

To increase the resistance to air at the side 1C of the housing, thereby making it equal to the resistance to air at the back lB, the fins 9 are arranged at the short pitch PPh on the short straight part 7f of the unit 7D. The speed of air flow at the back 1B and the speed of air flow at the side 1C are thereby equalized.

As a result of this, the air will make no noise.

In all embodiments described above, the first heat-exchanging unit (7, 7A, 7B, 7C or 7D) is L-shaped as viewed from above. Nonetheless, the shape of the first heat-exchanging unit is not limited to this.

Instead, this heat-exchanging unit may be U-shaped, surrounding the propeller fan 15. If so, an air-inlet port is provided in each side of the housing 1.

Claims

Claims:

1. An outdoor unit of an air-conditioner, comprising: a rectangular housing having a back, two sides and a front; a first air-inlet port made in the back of said housing; a second air-inlet port made in at least one of the sides of said housing; an air-outlet port made in the front of said housing; an outdoor heat exchanger provided in said housing; and a fan provided in said housing, for guiding air to said outdoor heat exchanger through said first and second air-inlet ports and discharging the air from said housing through said air-outlet port after the air has released or taken heat at said outdoor heat exchanger, wherein said outdoor heat exchanger comprises a first heat-exchanging unit which is constituted by a first part extending along said first air-inlet port and a second part extending along said second air-inlet port, and a second heat-exchanging unit which is located upstream of said first heat-exchanging unit with respect to an air stream generated by said fan, which extends along said first air-inlet port and which is interposed between said first air-inlet port and said first heat-exchanging unit.

2. The outdoor unit according to claim 1, wherein said second air-inlet port is made in only one of the sides of said housing, and said first heat-exchanging unit is L-shaped and extends along said first and second air-inlet ports which are made in the back and side of said housing.

3. The outdoor unit according to claim 1, wherein said fan comprises a fan motor having a shaft and a propeller fan mounted on the shaft of the fan motor, and said first and second heat-exchanging units are of fined-tube type, each comprising a plurality of fins which are juxtaposed at a short pitch and a heatexchanging pipe which passes through the fins and through which refrigerant flows.

4. The outdoor unit according to claim 3, wherein the heat-exchanging pipe of said first heat-exchanging unit has a diameter (4da) larger than a diameter (+dub) of the heat-exchanging pipe of said second heat-exchanging unit (+da > fob).

5. The outdoor unit according to claim 4, wherein the heat-exchanging pipe of said first and second heatexchanging units extend parallel to each other and along the air stream generated by said fan.

6. The outdoor unit according to claim 4, wherein the heat-exchanging pipes of said first and second heat-exchanging units meander, each having a plurality of straight portions, and the straight portions of the heat-exchanging pipe of said first heat-exchanging unit are arranged in staggered fashion with respect to the straight portions of the heat-exchanging pipe of said second heat-exchanging unit.

7. The outdoor unit according to claim 4, wherein the heat-exchanging pipes of said first and second heat-exchanging units meander, each having a plurality of straight portions, the straight portions of the heat-exchanging pipe of said first heat-exchanging unit are arranged at a first pitch (PPc), and the straight portions of the heat-exchanging pipe of said second heat-exchanging unit are arranged at a second pitch (PPd) shorter than the first pitch (PPc) (PPc > PPd).

8. The outdoor unit according to claim 3, wherein the refrigerant is guided first into said first heat-exchanging unit and then into said second heat-exchanging unit while said outdoor heat exchanger is operating as a condenser in cooling mode.

9. The outdoor unit according to claim 8, wherein said outdoor heat exchanger incorporates two refrigerant passages through which the refrigerant is supplied at the same time.

10. The outdoor unit according to claim 3, wherein the fins of said second heat-exchanging unit are juxtaposed at a pitch (PPf) longer than a pitch (PPe) at which the fins of said first heat-exchanging unit are juxtaposed (PPf > PPe).

11. The outdoor unit according to claim 3, wherein the fins of the second part of said first heat-exchanging unit are juxtaposed at a pitch (PPh) shorter than a pitch (PPg) at which the fins of the first part of said first heat-exchanging unit are juxtaposed.

12. An air-conditioner unit, substantially as hereinbefore described with reference to FIGS. 1 to 9.

12. An indoor unit of an air-conditioner, substantially as hereinbefore described with reference to FIGS. 1 to 9.

Amendments to the claims have been filed as tollows

1. An air-conditioner unit, comprising: a rectangular housing having a back, two sides and a front; a first air-inlet port made in the back of said housing; a second air-inlet port made in at least one of the sides of said housing; an air-outlet port made in the front of said housing; a heat exchanger provided in said housing; and a fan provided in said housing, for guiding air to said heat exchanger through said first and second air-inlet ports and discharging the air from said housing through said air-outlet port after the air has released or taken heat at said heat exchanger, wherein said heat exchanger comprises a first heat-exchanging unit which is constituted by a first part extending along said first air-inlet port and a second part extending along said second air-inlet port, and a second heat-exchanging unit which is located upstream of said first heat-exchanging unit with respect to an air stream generated by said fan, which extends along said first air-inlet port and which is interposed between said first air-inlet port and said first heat-exchanging unit.

2. The unit according to claim 1, wherein said second air-inlet port is made in only one of the sides of said housing, and said first heat-exchanging unit is L-shaped and extends along said first and second air-inlet ports which are made in the back and side of said housing.

3. The unit according to claim 1, wherein said fan comprises a fan motor having a shaft and a propeller fan mounted on the shaft of the fan motor, and said first and second heat-exchanging units are of fined-tube type, each comprising a plurality of fins which are juxtaposed and a heatexchanging pipe which passes through the fins and through which refrigerant flows.

4. The unit according to claim 3, wherein the heat-exchanging pipe of said first heat-exchanging unit has a diameter (0da) larger than a diameter (*dub) of the heat-exchanging pipe of said second heat-exchanging unit (0da > fob).

5. The unit according to claim 4, wherein the heat-exchanging pipe of said first and second heatexchanging units extend parallel to each other and along the air stream generated by said fan.

6. The unit according to claim 4, wherein the heat-exchanging pipes of said first and second heat-exchanging units meander, each having a plurality of straight portions, and the straight portions of the heat-exchanging pipe of said first heat-exchanging unit are arranged in staggered fashion with respect to the straight portions of the heat-exchanging pipe of said second heat-exchanging unit.

7. The unit according to claim 4, wherein the heat-exchanging pipes of said first and second heat-exchanging units meander, each having a plurality of straight portions, the straight portions of the heat-exchanging pipe of said first heat-exchanging unit are arranged at a first pitch (PPc), and the straight portions of the heat-exchanging pipe of said second heat-exchanging unit are arranged at a second pitch (PPd) shorter than the first pitch (PPc) (PPc > PPd).

8. The unit according to claim 3, wherein the refrigerant is guided first into said first heat-exchanging unit and then into said second heat-exchanging unit while said heat exchanger is operating as a condenser in cooling mode.

9. The unit according to claim 8, wherein said - heat exchanger incorporates two refrigerant passages through which the refrigerant is supplied at the same time.

10. The unit according to claim 3, wherein the fins of said second heat-exchanging unit are juxtaposed at a pitch (PPf) longer than a pitch (PPe) at which the fins of said first heat-exchanging unit are juxtaposed (PPf > PPe).

11. The unit according to claim 3, wherein the fins of the second part of said first heat-exchanging unit are juxtaposed at a pitch (PPh) shorter than a pitch (PPg) at which the fins of the first part of said first heat-exchanging unit are juxtaposed.