Indoor unit for an air conditioning system

Abstract: This invention relates to an indoor unit for an air conditioning system. The indoor unit is characterised in that a louver (10) is turnable in two opposite directions from a closing position at which the louver substantially closes an outlet port(1). The louver has a curved cross section with a concave surface (10a) and an opposite convex surface (10b). Further, control means (27) is provided ,and the control means controls the movement of the louver so that the concave surface is directed substantially upwards when the conditioned air is to be discharged forwards, and so that the concave surface is directed substantially backwards when the conditioned air is to be discharged downwards.

Description: BACKGROUND OF THE INVENTION Field of The Invention The present invention relates generally to an air conditioning system and an indoor unit thereof. More specifically, the invention relates to an air conditioning system, which has an indoor unit equipped with a horizontally extending louver for vertically changing the discharge direction of a conditioned air, and a remote controller for remote-controlling the pivotal movement of the louver of the indoor unit. Description of The Prior Art EP-A-0 657 701 discloses an indoor unit for an air conditioner, comprising an outlet port for discharging a conditioned air into a room, an inlet port for sucking an air to be conditioned from the room, a discharge passage for allowing the conditioned air to flow in a forward and downward direction toward said outlet port, pivotable rear and front louvers provided in said outlet port, for vertically changing a discharge direction of said conditioned air, and controllable drive means for driving said louvers for turning movement. US-A-5 234 373 discloses an indoor unit for an air conditioner in which a front louver is turnable in only one direction upwardly from its closing position, while a rear louver is turnable in opposite directions from its closing position. A gap is formed between a front edge of the front louver and a front wall of an outlet port when the front louver is in its closing position. Moreover, a gap between the front louver and the rear louver is visible from the user's eye-point. Another conventional indoor unit for an air conditioning system is described hereinbelow with reference to FIG. 33 of the attached drawings. Said indoor unit comprises a front panel 203, an outlet port 201 provided beneath the front part of the front panel 203 for discharging a conditioned air into a room, and a discharge passage 202 for discharging the conditioned air toward the outlet port 201 in a forward and downward direction. The outlet port 201 is provided with a horizontally extending louver 300, which is pivotable about a pivotal axis C for vertically changing the discharge direction of the conditioned air. The louver 300 has a cross section, which is curved so as to correspond to the shape of the outer surface of the front panel 203 (convex forwards and downwards) when the operation of the air conditioning system is stopped, in order to improve the appearance of the indoor unit (see the two-dot chain line of FIG. 33). The direction of a conditioned air discharged from the indoor unit may be set to be an optional direction in accordance with the choice of a user, although it is generally a substantially forward direction when cooling and a substantially downward direction when heating. When the louver 300 of the indoor unit is arranged at a substantially horizontal position (convex downwards) shown in FIG. 33A, it allows the conditioned air to be discharged in a forward direction from the outlet port 201, and when the louver 300 is arranged at a substantially vertical position (convex rearwards) shown in FIG. 33B, it allows the conditioned air to be discharged in a downward direction from the outlet port 201. In a case where the direction of the conditioned air discharged from the indoor unit is changed to an optional direction between the forward and downward directions, one end 302 of the louver 300 is always directed toward the upstream of the conditioned air and the other end 301 thereof is always directed toward the downstream of the conditioned air between the substantially horizontal position (convex downwards) shown in FIG. 33A and the substantially vertical position (convex rearwards) shown in FIG. 33B. FIG. 34 shows another example of a conventional indoor unit for an air conditioning system. In this indoor unit, a horizontally extending louver 310 is substituted for the louver 300. When the louver 310 is arranged at a substantially horizontal position (convex upward) shown in FIG. 34A, it allows a conditioned air to be discharged in a forward direction from the outlet port 201, and when the louver 310 is arranged at a substantially vertical position (convex forwards) shown in FIG. 34B, it allows the conditioned air to be discharged in a downward direction from the outlet port 201. In a case where the direction of the conditioned air discharged from the indoor unit is changed to an optional direction between the forward and downward directions, one end 311 of the louver 310 is always directed toward the upstream of the conditioned air and the other end 312 thereof is always directed toward the downstream of the conditioned air between the substantially horizontal position (convex upwards) shown in FIG. 34A and the substantially vertical position (convex forwards) shown in FIG. 34B. In the case of the conventional indoor unit for an air conditioning system shown in FIG. 33, when the louver 300 is arranged at the substantially horizontal position (convex downwards) shown in FIG. 33A, the side of the one end 302 of the louver 300 is substantially parallel to the flowing direction of the conditioned air, so that it is possible to allow the conditioned air to smoothly flow forwards along the louver 300. However, when the louver 300 is arranged at the substantially vertical position (convex rearwards) shown in FIG. 33B, the angle between the side of the one end 302 of the louver 300 and the flowing direction of the conditioned air is great, so that the conditioned air flow collides with the louver 300. Therefore, it is not possible to allow the conditioned air to smoothly flow downwards along the louver 300, and the louver 300 also serves as a baffle board against the conditioned air flow. For that reason, in the state shown in FIG. 33B, there are problems in that the discharge flow rate of the conditioned air is remarkably decreased and that noises due to turbulence of the conditioned air flow are increased. On the other hand, in the case of the conventional indoor unit for an air conditioning system shown in FIG. 34, when the louver 310 is arranged at the substantially vertical position (convex forwards) shown in FIG. 34B, the one end 311 of the louver 310 is substantially parallel to the flowing direction of the conditioned air, so that it is possible to allow the conditioned air to smoothly flow downwards along the louver 310. However, when the louver 310 is arranged at the substantially horizontal position (convex upwards) shown in FIG. 34A, the angle between the one end 311 of the louver 310 and the flowing direction of the conditioned air is great, so that the conditioned air flow collides with the louver 310. Therefore, it is not possible to allow the conditioned air to smoothly flow forwards along the louver 310, and the louver 310 also serves as a baffle board against the conditioned air flow. For that reason, in the state shown in FIG. 34A, there are the same problems as those in the aforementioned state shown in FIG. 33B Thus, according to the conventional indoor units shown in FIGS. 33 and 34, in a case where the discharge direction of a conditioned air is sequentially changed between the forward and downward directions, it is not always possible to allow the conditioned air to smoothly flow along the louver 300 or 310, so that it is not possible to prevent the decrease of the discharge flow rate of the conditioned air and the occurrence of noises due to turbulence of the conditioned air flow. SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the aforementioned problems and to provide an indoor unit for an air conditioning system, which can sequentially change the discharge direction of a conditioned air between forward and downward directions, while allowing the conditioned air to smoothly flow along a horizontally extending louver to ensure a sufficient discharge flow rate of conditioned air and while preventing the occurrence of noises due to turbulence of the conditioned air flow. This and other objects of the present invention are accomplished by an indoor unit as specified in claim 1. Improvements thereof are specified in sub-claims being dependent on claim 1. In addition, the control means may control the drive means so that turning speed, during the turning over movement, of the louver having a curved cross section is higher than turning speed during the usual turning movement. According to this indoor unit, since the turning speed during the turning over movement of the louver is higher than the turning speed of during the usual turning movement, it is possible to decrease the time required to reverse the louver. Therefore, it is possible to decrease the occurring time of noises due to the turbulence of the conditioned air caused by the louver during the turning over movement. Moreover, the control means may control the drive means so that the louver having a curved cross section is stopped for a predetermined period of time immediately before the turning over movement starts. The indoor unit may further comprise manually operable means for commanding operation and stop of the drive means to the control means, to move the louver to an optional pivotal position, and wherein the control means controls the drive means so that the louver having a curved cross section is stopped at a position other than the closing position when the control means receives a stopping command from the manually operable means during the turning over movement of the louver having a curved cross section. According to this unit, even if the stopping command is received from the manually operable means during the turning over movement, it is possible to stop the louver other than the closing position at which the louver closes the outlet port, so that it is possible to prevent the discharge of the conditioned air from being blocked by the louver by which the outlet port is closed. Therefore, it is possible to prevent the occurrence of noises, the freezing of the heat exchanger when cooling due to the decrease of the discharge flow rate, and the abnormal temperature rise of the heat exchanger when heating. Alternatively, the indoor unit may further comprise: manually operable means for commanding operation and stop of the drive means to the control means, to turning the louver to an optional pivotal position, and wherein the control means controls the drive means so that turning speed of the louver when automatically causing turning movement of the louver is higher than turning speed of the louver when causing turning of the louver in response to an input at the manually operable means, at least in a part of the turning range of said louver. According to this indoor unit, since the turning speed of the louver when automatically causing the pivotal movement of the louver is higher than the turning speed of the louver when causing the pivotal movement of the louver in response to the input of the manually operable means at least in a part of pivotal range of the louver, it is possible to decrease the time required to move the louver when automatically causing the turning movement of the louver, while maintaining the turning speed when causing the turning movement of the louver in response to the input of the manually operable means, at a low speed. Therefore, it is possible to decrease the time required to automatically move the louver at least in a part of pivotal range of the louver, and to easily carry out the positioning of the pivotal position of the louver by means of the manually operable means. The drive means may comprise at least one stepping motor, having exciting coils, and wherein the control means changes a rotational speed of said step motor for changing turning speed of the louver by switching an exciting system of the step motor between a one-two-phase exciting system and a two-phase exciting system. Alternatively, the drive means may comprise at least two motors, and wherein the control means controls the motors so that the plurality of louvers are independently operated. In the indoor unit, when each of said louvers are located at said closing position, a gap is formed between the adjacent louvers so that the louvers are turned without causing interference of pivotal loci of the louvers. According to this indoor unit, it is possible to prevent the louvers from colliding with each other. Therefore, in a case where the pivotal movements of the louvers are independently carried out, it is not required to carry out any complicated controls in order to prevent the louvers from colliding with each other, so that it is possible to more easily provide an indoor unit having a good discharge characteristic of conditioned air. In the indoor unit, a rear end edge of a front louver of the adjacent louvers is located below a front end edge of a rear louver of the adjacent louvers, when each of the louvers are located at the closing position. According to this indoor unit, it is possible to prevent the appearance of the indoor unit from being spoiled even if a sufficient gap is formed between the respective louvers. In the indoor unit, the foremost louver of said plurality of louvers is provided so as to be turnable in only one direction from the closing position, and the other louver of the louvers is provided so as to be turnable in two directions from the closing position, the other louver having the curved cross section. The foremost louver of said plurality of louvers may have a wind deflecting surface for deflecting the conditioned air in a forward and upward direction, the wind deflecting surface being arranged at a downstream end portion, with respect to a flow of conditioned air, of one surface of the foremost louver, and the foremost louver of the plurality of louvers may form a flow of conditioned air toward the inlet port from the outlet port via the wind deflecting surface when the foremost louver is turned to a predetermined position. According to this indoor unit, the conditioned air discharged from the outlet port when carrying out the dehumidifying operation of the air conditioning system, is discharged from the outlet port to the inlet port without being discharged toward the central portion of the room, and circulates near the indoor unit, so that it is possible to dehumidify the room without giving a cold wind feeling. In addition, it is possible to surely form a circulating flow even it the pivotal position of the louver is slightly shifted from the optimum pivotal position, by providing the wind deflecting surface. The wind deflecting surface may be formed so as to deflect the conditioned air discharged from the outlet port toward the downstream of a peripheral edge of the outlet port when the flow of conditioned air flowing from the outlet port toward the inlet port is formed. In addition, an inner wall surface forming the discharge passage on the side of the inlet port may be formed with a curved surface projecting toward the foremost louver, and the lowest end of the curved surface may be located upstream of the wind deflecting surface in a case where the foremost louver is located so as to form a flow of conditioned air flowing from the outlet port to the inlet port. Moreover, a portion of the louver upstream of the wind deflecting surface may have a plate-like shape. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 is a cross sectional view of an indoor unit in the first preferred embodiment of an air conditioning system; FIG. 2 is a perspective view illustrating the appearance of the indoor unit of FIG. 1; FIG. 3 is a perspective view illustrating a main part of the indoor unit wherein a front panel is removed; FIGS. 4A through 4D are partially cross-sectional views, each of which illustrates the relationship between the pivotal movement of a horizontally extending louver and the discharge direction of a conditioned air in the indoor unit of FIG. 1; FIG. 5 is a schematic view illustrating the range of discharge direction of a conditioned air in the indoor unit of FIG. 1; FIG. 6 is a schematic block diagram illustrating a main part of a control circuit in the first preferred embodiment of an air conditioning system; FIG. 7 is a schematic view illustrating an example of a basic structure of a louver driving motor (a step motor) of FIG. 6; FIG. 8 is a block diagram illustrating an example of the louver driving motor (the step motor) of FIG. 7 and a drive circuit for the louver driving motor; FIGS. 9A and 9B are graphs, each of which illustrates an example of an exciting pulse of a two-phase exciting system for the step motor of FIG. 7; FIGS. 10A and 10B are graphs, each of which illustrates an example of an energizing pulse of one-two-phase exciting system for the step motor of FIG. 7; FIGS. 11A and 11B are flowcharts illustrating the relationship between the operation of a remote controller of FIG. 6 and the remote control of a horizontally extending louver; FIG. 12 is a flowchart for controlling the pivotal movement of a horizontally extending louver in the first preferred embodiment of an air conditioning system; FIG. 13 is a flowchart which can be added to the flowchart of FIG. 12; FIG. 14 is a cross sectional view of a main part of an indoor unit in the second preferred embodiment of an air conditioning system according to the present invention; FIG. 15 is a perspective view of a main part of the indoor unit of FIG. 14 wherein a front panel is removed; FIG. 16 is a schematic block diagram illustrating a main part of a control circuit in the second preferred embodiment of an air conditioning system according to the present invention; FIG. 17A through 17C are partially cross-sectional views each of which illustrating the relationship between the pivotal movement of a horizontally extending louver and the discharge direction of a conditioned air in the indoor unit of FIG. 14; FIG. 18 is a schematic view illustrating the range of the discharged direction of a conditioned air in the indoor unit of FIG. 14; FIGS. 19A through 19E are partially cross-sectional views, each of which illustrates the relationship between the pivotal movement of a horizontally extending louver and the discharge direction of a conditioned air in the third preferred embodiment of an indoor unit according to the present invention; FIG. 20 is a schematic view illustrating the range of discharge direction of a conditioned air in the indoor unit of FIG. 19. FIG. 21 is a flowchart for controlling the pivotal movement of a horizontally extending louver in the third preferred embodiment of an air conditioning system according to the present invention; FIG. 22 is a flowchart for controlling the pivotal movement of a horizontally extending louver in the fourth preferred embodiment of an air conditioning system according to the present invention; FIG. 23 is a view illustrating desired shape and arrangement of a horizontally extending louvers; FIG. 24 is a cross sectional view illustrating the movement of the louver of FIG. 23; FIG. 25 is a view illustrating other desired shape and arrangement of horizontally extending louvers; FIG. 26 is a view illustrating other desired shape and arrangement of a horizontally extending louver; FIG. 27 is a view illustrating other desired shape and arrangement of horizontally extending louvers; FIG. 28 is a cross sectional view of an indoor unit in the fifth preferred embodiment of an air conditioning system according to the present invention; FIG. 29 is a block diagram illustrating a refrigeration cycle of an air conditioning system according to the present invention; FIG. 30 is an enlarged cross sectional view of a main part of a foremost louver of FIG. 28; FIG. 31 is an enlarged cross sectional view of a main part of an outlet portion of an indoor unit in the sixth preferred embodiment of an air conditioning system according to the present invention; FIG. 32 is an enlarged cross sectional view of a main part of an outlet portion of an indoor unit in the seventh preferred embodiment of an air conditioner according to the present invention; FIGS. 33A and 33B are partially cross-sectional views, each of which illustrates the relationship between the pivotal movement of a horizontally extending louver and the discharge direction of a conditioned air in a conventional indoor unit for an air conditioning system; and FIGS. 34A and 34B are partially cross-sectional views similar to FIGS. 33A and 33B, in another conventional indoor unit for an air conditioning system. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the accompanying drawings, the preferred embodiments of the present invention will be described below. However, the embodiment presented as the first preferred embodiment in the description and shown in Fig. 1 to Fig.13 does not fall within the scope of the claims. [First Preferred Embodiment] FIGS. 1 through 13 show the first preferred embodiment In FIGS. 1 and 2, an indoor unit U for an air conditioning system is designed to be mounted on a wall at an overhead location in a room. The indoor unit U comprises a front panel 3, an outlet port 1 for discharging a conditioned air (a cooled air, a dehumidified air, a heated air or the like) into the room, and a discharge passage 2 for allowing the conditioned air to flow toward the outlet port 1 in a forward and downward direction. The outlet port 1 is provided with a horizontally extending louver 10, which is pivotable (pivotally movable) or turnable about a pivotal axis C (see FIG. 1) for vertically changing the discharge direction of the conditioned air. The louver 10 is driven by drive means or a louver driving motor M (see FIG. 3). In FIG. 1, reference number 9 denotes a plurality of vertically extending louvers provided upstream of the louver 10 for horizontally changing the discharge direction of the conditioned air. As shown in FIG. 1, the pivotal axis C is located on the side of one end 11 of the louver 10, and shifted from the louver 10 in a thickness direction of the louver 10 (see arrow t of FIG. 1). In order to improve the appearance of the indoor unit U, louver 10 is pivotally moved to a closing position (a stopped position), at which the lower 10 substantially closes the outlet port 1, by means of the louver driving motor M, when the operation of the air conditioning system is stopped. The louver 10 has a curved cross section (convex forwards and downwards) so as to correspond to the shape of the outer surface of the front panel 3 (see the two-dot chain line of FIG. 1). That is, the louver 10 has a cross section which is curved toward the pivotal axis C at a location substantially facing the pivotal axis C, and has a concave surface 10a on the side of the pivotal axis C and a convex surface 10b on the opposite side of the pivotal axis C. The cross section of the discharge passage 2 is defined by a front wall 2a and a rear wall 2b. A plate-like supporting member 15 for supporting the louver 10 at the central portion thereof with respect to the axial direction of the pivotal axis C is provided in the discharge passage 2. The supporting member 15 has a base portion 16, both ends of which are supported on the front wall 2a and the rear wall 2b, respectively, and a supporting portion 17 which extends forwards and downwards from the base portion 16 on the side of the front wall 2a. On the side of the pivotal axis C of the louver 10, a mounting plate 13 is provided. The tip portion of the mounting plate 13 is pivotally mounted to the tip portion of the supporting portion 17 of the supporting member 15 at a location of the pivotal axis C. For sucking an indoor air to be conditioned, the front panel 3 has an inlet port 4 in the front surface thereof, and an inlet port 5 in the upper surface thereof. Inside of the front panel 3, a main indoor heat exchanger 6 is provided. The main indoor heat exchanger 6 comprises a first heat exchanger 6a (see FIG. 3) corresponding to the inlet port 4 and a second heat exchanger 6b corresponding to the inlet port 5. Between the inlet port 5 and the second heat exchanger 6b, an auxiliary indoor heat exchanger (a supercooling heat exchanger) 7 is provided. Inside of the main indoor heat exchanger 6 (between the first heat exchanger 6a and the second heat exchanger 6b), a cross-flow or transverse type indoor fan 8 is provided. The indoor unit U is designed to suck an indoor air from the inlet ports 4 and 5 by the rotation of the indoor fan 8. The indoor air sucked from the inlet port 4 flows into the discharge passage 2 through the first heat exchanger 6a, and the indoor air sucked from the inlet port 5 flows into the discharge passage 2 through the auxiliary indoor heat exchanger 7 and the second heat exchanger 6b. Referring to FIGS. 4 and 5, the relationship between the pivotal movement of the louver 10 and the discharge direction of a conditioned air will be described in detail below. Furthermore, the slant line area of FIG. 5 shows the discharged area of a mainstream portion having a flow velocity of greater than a predetermined velocity (this is the same as FIGS. 18 and 20 which will be described later). As shown in FIG. 4C, the louver 10 is pivotable or turnable within the range of about 180 degrees between a position at which the one end 11 of the louver 10 is directed toward the upstream of the conditioned air when the louver 10 is substantially parallel to the discharge direction of the conditioned air flowing through the discharge passage 2, and a position at which the other end 12 of the louver 10 is directed toward the upstream of the conditioned air when the louver 10 is substantially parallel to the direction of the conditioned air flowing through the discharge passage 2, via the stopped position. Furthermore, the supporting member 15 is formed so as not to interfere with the pivotal movement of the louver 10. The louver 10 allows a conditioned air to be discharged in a forward direction from the outlet port 1 when the louver 10 is arranged at a substantially horizontal position as shown in FIG. 4A, i.e., when the concave surface 10a is directed substantially upwards (see sign a of FIG. 5). The louver 10 also allows a conditioned air to be discharged in a downward direction from the outlet port 1 when the louver 10 is arranged at a substantially vertical position as shown in FIG. 4B, i.e., when the concave surface 10a is directed substantially backwards (see sign d of FIG. 5). When the discharge direction of the conditioned air is changed from the forward direction to the downward direction, the louver 10 is subjected to following movements. (1) First, the louver 10 is turned, from the substantially horizontal position (see FIG. 4A), so as to direct the one end 11 (the front end) the louver 10 downwards, so that the concave and convex surfaces 10a,10b of the louver 10 is substantially parallel to the direction of the conditioned air flowing through the discharge passage 2 (see FIG. 4A). During abovementioned movement, the discharge direction of the conditioned air is changed from the forward direction to the forward and downward direction continuously in accordance with the change of the pivotal position of the louver 10 (see signs a and b of FIG. 5). (2) Next, the louver 10 is turned in a reverse direction by substantially 180 degrees so that the positions of the one end 11 and the other end 12 of the louver 10 are mutually exchanged. During the reversal or the turning over movement, the louver 10 passes by its stopping position or its closing position (see arrow T of FIG. 4C). In this case, the discharge direction of the conditioned air after the reversal is slightly shifted downwards in comparison with the state before the reversal (see sign c of FIG. 5). (3) Next, the louver 10 is turned, to the substantially vertical position (see FIG. 4D), so as to direct the other end 12 (the front-lower end) thereof downwards. During this turning movement, the discharge direction of the conditioned air is changed continuously from the forward and downward direction to the downward direction in accordance with the change of the pivotal position of the louver 10 (see signs c through d of FIG. 5). The abovementioned movements of the lower 10, to change the discharge direction from forward to downward, will be hereinafter referred to a "downward movement (of the louver 10)". This movement is the same in the case of a louver 20 in the second and third preferred embodiments which will be described later. Furthermore, the term "upstream" means "upstream, with respect to the flowing direction of the conditioned air", and the term "downstream" means "downstream, with respect to the flowing direction of the conditioned air", in this specification. In addition, each movement mentioned in above items (1) and (3) is referred to an "usual turning movement", and the movement mentioned in above item (2) is referred to a "turning over movement". On the other hand, in a case where the discharge direction of the conditioned air is changed from the downward direction to the forward direction, the louver 10 is turned, from the substantially vertical position (see FIG. 4D) to the substantially horizontal position (see FIG. 4A), with movements opposite to aforementioned movements (1)-(3). The abovementioned movements of the louver 10, to change the discharge direction from downward to forward, will be hereinafter refer to a "upward movement (of the louver 10)". This movement is the same in the case of a louver 20 in the second and third preferred embodiment which will be described later. In a case where the louver 10 is pivotally moved upwards or downwards, a part of the pivotal movement of the louver 10 during the reversal thereof (see FIG. 4C), will be hereinafter referred to a "discontinuous part of the discharged direction of conditioned air", and the other part during the usual pivotal movement of the louver 10 will be hereinafter referred to as a "continuous part of the discharged direction of conditioned air" (these parts are the same in the case of a louver 20 in the second and third preferred embodiment which will be described later). As shown in FIG. 6, the indoor unit U has a manually operable means or a remote controller R for transmitting an infrared signal or a remote control signal to remote-control the pivotal movement of the louver 10. The indoor unit U also has a receiving unit 25 (see FIGS. 2 and 3) for receiving the remote control signal transmitted from the remote controller R, and a receiving sound producing means 26 for producing a receiving sound in response to the remote control signal received by the receiving unit 25. Moreover, the indoor unit U has an inspecting input means (a switch provided in the indoor unit body) 29 for verifying the movement of the louver 10 when the product is inspected before being shipped or the like. In addition, the indoor unit U has a control unit 27, and a drive circuit 28 for driving the louver driving motor M. The control unit 27 drives the louver driving motor M by means of the drive circuit 28 in response to the remote control signal (input) of the remote controller (the manually operable means) R received by the receiving unit 25, to control the pivotal movement of the louver 10 When the operation of the air conditioning system is started or stopped, the control unit 27 controls the operation of the louver driving motor M so as to automatically cause the pivotal movement of the louver 10 to a predetermined position (e.g., the aforementioned stopped position). In addition, the control unit 27 controls the louver driving motor M in response to the input from the aforementioned inspecting input means 29 to cause the pivotal movement of the louver 10. Referring to FIGS. 7 through 10, the louver driving motor M and the drive circuit 28 will be described in detail below. The louver driving motor M comprises a step motor. As an example of such a step motor, a PM type step motor is shown in FIG. 7. In FIG. 7, the step motor comprises a rotor 50 having a north pole and a south pole, and a stator 52 having four exciting coil portions 1 through 4 which are shifted by 90 degrees from the adjacent exciting coil portion. In addition, switches SW1 through SW4 corresponding to the exciting coil portions 1 through 4 of the stator 52 are provided. When these switches SW1 through SW4 are turned on, currents pass through the corresponding exciting coil portions 1 through 4 from a direct voltage source 60, so that the exciting coil portions 1 through 4 are excited (the south pole rises). In the step motor of this construction, when only the switch SW1 is turned on, the exciting coil portion 1 is excited (the south pole rises) to attract the north pole of the rotor 50 (the state shown in FIG. 7). Then, when the switch SW1 is turned off and only the switch SW2 is turned on, the exciting coil portion 2 is excited to attract the north pole of the rotor 50 to rotate the rotor 50 clockwise by 90 degrees. When the exciting coil portions 1 through 4 are sequentially energized by switching the switches SW1 through SW4 in the order of 3→4→1..., the rotor 50 can be rotated clockwise every 90 degrees. In order to reverse the rotation of the rotor 50 to rotate the rotor 50 counterclockwise, the exciting order of the exciting coil portions 1 through 4 may be reversed so as to be 4→3→2 →1→4···, which is opposite to the exciting order in the case of the clockwise rotation. As shown in FIG. 8, the drive circuit 28 for driving the louver driving motor comprises a distributing circuit 64, to which a clock pulse 62 is inputted, and an exciting circuit 66, to which the direct voltage source 60 is connected. The distributing circuit 64 serves to determine the energizing order of the exciting coil portions 1 through 4 of the step motor. The exciting circuit 66 serves to use an output signal (an energizing pulse) outputted from the distributing circuit 64 for energizing the exciting coil portions 1 through 4 of the step motor by a predetermined voltage and by a predetermined exciting system. The clock pulse 62 inputted to the distributing circuit 64 is a pulse signal having a predetermined frequency. When the frequency (pulse/sec) of the clock pulse 62 is changed, the output frequency of the energizing pulse outputted from the distributing circuit 64 is changed, so that the rotational speed of the step motor can be changed. FIGS. 9 and 10 show output signals (energizing pulses) from the distributing circuit 64, together with the clock pulse 62. FIG. 9 shows an energizing pulse of a two-phase energizing system or a two-phase exciting system for energizing the exciting coil portions 1 through 4 of the step motor every two phases. FIG. 10 shows an energizing pulse of a one-two-phase energizing system or a one-two phase exciting system for alternately carrying out a one-phase energizing system (a one-phase exciting system) for energizing the exciting coil portions 1 through 4 every phase, and the two-phase energizing system. The one-two-phase energizing system shown in FIG. 10 needs a pulse number, which is two times as large as that of the two-phase energizing system shown in FIG. 9, in order to obtain the same number of revolution (rotation angle). That is, the ratio of the rotational speed of the step motor in the two-phase energizing system to the rotational speed thereof in the one-two-phase energizing system is 1:2 with respect to the clock pulse 62 of the same frequency (see FIG. 9A and FIG. 10A). Furthermore, although the torque of the step motor generally decreases as the output frequency of the energizing pulse increases, the torque of the stepping motor does not change only by switching the energizing system of the energizing pulse between the one-two-phase and two-phase energizing systems. The control unit 27 can change the rotational speed of the louver driving motor M on the basis of the aforementioned properties of the step motor. For example, it is assumed that the rotational speed of the step motor rotated by the energizing pulse of a predetermined normal output frequency in the one-two-phase energizing system shown in FIG. 10A is a usual rotational speed. In the same one-two-phase energizing system shown in FIG. 10B, if the frequency of the clock pulse 62 is increased by three times so that the output frequency of the energizing pulse is increased to be three times as large as the aforementioned normal output frequency, a rotational speed three times as large as the usual rotational speed can be obtained. In addition, as shown in FIG. 9B, in the two-phase energizing system, if the frequency of the clock pulse 62 is increased by one and a half times so that the output frequency of the energizing pulse is increased to be one and a half times as large as the aforementioned normal output frequency, a rotational speed three times (2×1.5 times) as large as the usual rotational speed can be obtained although the torque of the louver driving motor M is slightly decreased. Furthermore, a rotational speed two times as large as the usual rotational speed may be obtained without decreasing the torque only by switching the energizing system of the louver driving motor M from the one-two-phase energizing system to the two-phase energizing system. In this case, since the torque of the louver driving motor M is not changed, it is possible to maintain a good rotation even if a load is applied to the louver 10. The control unit 27 can determine the current position of the louver 10 from a predetermined initial position of the louver 10 on the basis of the order and number of the energizing pulse applied to the louver driving motor or the step motor M. That is, it can be determined on the basis of the order of the energizing pulse whether the rotational direction of the louver 10 is clockwise or counterclockwise, and the rotation angle in the rotational direction can be determined on the basis of the number of energizing pulse. For example, assuming that the aforementioned initial position is ○ and that the clockwise rotation is expressed by "+" (positive) and the counterclockwise rotation is expressed by "-"(negative), and if a step motor rotating by 0.5 degrees every pulse (having a step angle of 0.5 degrees) is used, the direction and degree of angular movement of the louver 10 from the initial position can be recognized by the addition and/or subtraction on the basis of the rotational direction and the energizing pulse number. Furthermore, a conventional A.C. or D.C. motor can be used for the louver driving motor, however in such a case, in order to recognize the rotational position of the louver 10, it is required provide an additional position sensor for detecting the rotational position of the louver 10. The control unit 27 causes the receiving sound producing means 26 to produce a predetermined receiving sound in response to a remote control signal received by the receiving unit 25. The receiving sound produced by the receiving sound producing means 26 during the reversal of the louver 10 as shown in FIG. 4C, is different from the receiving sound produced by the receiving sound producing means 26 in the other periods of time as shown in FIGS. 4A, 4B and 4D. As methods for producing different receiving sounds, the tone colors (such as frequency components of sounds) of the receiving sounds may be different, or the receiving sounds may be produced at different intervals (e.g., a receiving sound such as "pipitt-pipitt" or "pii-pii" which is different from a receiving sound such as "pitt-pitt"). Referring to FIGS. 11 and 12, a method for changing the rotational position of the louver 10 by means of the remote controller (the manually operable means) R will be described below. As shown in the flowchart of FIG. 11A, the remote controller R may transmit a louver moving signal to start the pivotal movement or the turning movement of the louver 10 by pushing a louver operating button (not shown) once, and a louver stopping signal to stop the pivotal movement of the louver 10 by pushing the louver operating button again. Alternatively, as shown in the flowchart of FIG. 11B, the remote controller R may transmit a louver moving signal to start the pivotal movement of the louver 10 by pushing the louver operating button, and a louver stopping signal to stop the pivotal movement of the louver 10 by releasing the louver operating button after pivotally moving the louver 10 to a desired position by continuously pushing the louver operating button. In the flowchart of FIG. 12, the expression "louver positions d(m)" mean the respective pivotal positions of the louver 10 illustrated by the solid lines of FIGS. 4A through 4D. In this case, the values of m = 1∼4 are assigned to the respective pivotal positions of the louver 10 illustrated by the solid lines of FIGS. 4A through 4D. In addition, the expression "louver position d(0)" means the aforementioned closing position (see the louver 10 illustrated by the two-dot chain line in FIG. 1). Moreover, the expression "n=0" means the aforementioned "downward movement of the louver 10" and the expression "n=1" means the aforementioned "upward movement of the louver 10". In FIG. 12, n=0 (corresponding to the downward movement of the louver 10) is first set at step 70. Then, when it is determined at step 71 that the operation of the air conditioning system is started, the louver 10 is automatically moved from the closing position d(0) to the louver position d(m) corresponding to the operation mode (step 76). In this case, for example, m=3 is set in the heating operation mode, and m=1 is set in the cooling operation mode. On the other hand, when it is determined at step 71 that the operation of the air conditioning system is not started and when it is determined at step 72 that the air conditioning system is not operated, the air conditioning system stands by (step 75). When it is determined at step 72 that the air conditioning system is operated and when it is determined at step 73 that the operation stopping signal is received from the remote controller R, the stopping process for automatically moving the louver 10 to the stopped position or the closing position d(0) is carried out (step 74), and thereafter, the air conditioning system stands by (step 75). When the louver 10 is automatically moved at step 76 or 74, the pivotal speed or the turning speed of the louver 10 is set to be three times as large as an usual pivotal speed. In this case, the pivotal speed of the louver 10 is changed by changing the rotational speed of the louver driving motor (the step motor) by means of the control unit 27 as described above. Then, in the first loop, when it is determined at step 77 that the louver moving signal is received from the remote controller R after the operation is started or during the operation, it is determined at step 78 that n=0 (during the "downward movement") and at step 79 that m≠4, so that m=m+1 is set at step 85. Then, when it is determined at step 86 that m=3 (corresponding to the reversal or the turning over movement of the louver 10 during the "downward movement"), the pivotal speed of the louver 10 is set to be three times as large as the usual pivotal speed (step 89), and when it is determined at step 86 that m≠3, the pivotal speed of the louver 10 is set to be the usual pivotal speed (step 88). On the other hand, in and after the second loop, when it is determined at step 78 that n≠0 (not during the "downward movement") (i.e., n=1 (during the "upward movement"), and when it is determined at step 81 that m=1, it returns to n=0 (during the "downward movement") (step 82). When it is determined at step 81 that m≠1, m=m-1 is set at step 83. Then, when it is determined at step 84 that m=2 (corresponding to the reversal or the turning over movement of the louver 10 during the "upward movement"), the pivotal speed or the turning speed of the louver 10 is set to be three times as large as the usual pivotal speed (step 89), and when it is determined at step 84 that m≠2, the pivotal speed of the louver 10 is set to be the usual pivotal speed (step 88). Then, the louver 10 moves to the louver position d(m) at the pivotal speed set at step 88 or 89 (step 90). That is, as shown in FIG. 4C, in a case where the louver 10 is reversed from the louver position d(2) (illustrated by the two-dot chain line) to the louver position d(3) (illustrated by the solid line) during the downward movement (n=0), or in a case where the louver 10 is reversed from the louver position d(3) (illustrated by the solid line) to the louver position d(2) (illustrated by the two-dot chain line) during the upward movement (n=1), the pivotal speed is changed to be three times as large as the usual pivotal speed. Then, when it is determined at step 91 that a louver stopping signal is received (during the movement of the louver 10), and when it is not determined at step 92 that the louver 10 is reversed (n=0 and m=3, or n=1 and m=2), the pivotal movement of the louver 10 is closing at the current position (step 95). On the other hand, it is determined at step 92 that the louver 10 is reversed (n=0 and m=3, or n=1 and m=2), the louver 10 is moved to the louver position d(2) or the louver position d(3) (the reversal is completed), and then, the pivotal movement of the louver 10 is stopped (step 94). That is, while the louver 10 is reversed via the closing position d(0) at which the outlet port 1 is closed, even if the louver stopping signal is received from the remote controller R, the louver 10 is stopped at the louver position d(2) (during the "upward movement" (n=1)) or the louver position d(3) (during the "downward movement" (n=1)) other than the closing position d(0) at which the outlet port 1 is closed. On the other hand, when it is determined at step 91 that no louver stopping signal has been received and when it is determined at step 93 that the louver 10 has not reached the louver position d(m), the movement of the louver 10 toward the louver position d(m) is continued (steps 93→90→91→93). When it is determined at step 91 that no louver stopping signal has been received and when it is determined at step 93 that the louver 10 has reached the louver position d(m), the routine returns to step 78, and then, the louver 10 is moved toward the next louver position d(m). Furthermore, in the latter, after the louver 10 reaches the louver position d(4) during the "downward movement" (n=0), it should be determined at step 79 that m=4, so that m=1 (during the "upward movement") is set at step 80 and m=4-1=3 is set at step 83. That is, the movement of the louver 10 is switched from the "downward movement" (n=0) to the "upward movement" (n=1). With this construction, the advantages of this preferred embodiment will be described below. According to this preferred embodiment, in a case where the direction of a conditioned air discharged from the indoor unit U is changed between the forward and downward directions, it is possible to maintain the surfaces 10a, 10b of the upstream portion of the louver 10 (the other end 12 in FIGS. 4A and 4B, and the one end 11 in FIGS. 4C and 4D) so as to be parallel to the flowing direction of the conditioned air by reversing the louver 10 by about 180 degrees (see FIG. 4C). Thus, it is possible to sequentially change the discharge direction of the conditioned air from the forward direction to the downward direction and from the downward direction to the forward direction while allowing the conditioned air to smoothly flow along the louver 10 having the curved cross section. In addition, while the louver 10 is reversed via the closing position d(0) at which the outlet port 1 is closed (see FIG. 4(C)), even if the louver stopping signal is received from the remote controller R, it is possible to stop the louver 10 other than the closing position d(0) at which the outlet port 1 is closed, so that the discharge of the conditioned air is not blocked by the louver 10 by which the outlet port 1 is closed. Therefore, it is possible to prevent the discharge of the conditioned air from being blocked by the louver 10, so that it is possible to prevent the occurrence of noises, the freezing of the heat exchanger 6 due to the decrease of the discharge flow rate when the air conditioning system is in cooling operation, and the abnormal temperature rise of the heat exchanger 6 when the air conditioning system is in heating operation. In addition, in a case where the louver 10 is pivotally moved in response to the louver moving signal outputted from the remote controller R, the pivotal speed of the louver 10 during the reversal (the "turning over movement") is higher than the pivotal speed during the usual pivotal movement (the "usual turning movement"), so that the time required to reverse the louver 10 can be decreased. As a result, it is possible to decrease the occurring time of noises due to the turbulence of the conditioned air flow caused by the louver 10 during the reversal. In addition, when the operation of the air conditioning system is started or stopped, the pivotal speed of the louver 10 during the automatically pivotal movement is greater than the usual pivotal speed of the louver 10 when it is pivotally moved in response to the louver moving signal outputted from the remote controller R (except for during the reversal of the louver 10), so that it is possible to decrease the time required to move the louver 10 during the automatically pivotal movement while maintaining the usual pivotal speed at a low speed when the louver 10 is pivotally moved by means of the remote controller R. Therefore, it is possible to decrease the time required to automatically move the louver 10 when the operation of the air conditioning system is started or stopped, and it is also possible to easily carry out the positioning of the pivotal position of the louver 10 by means of the remote controller R. In addition, when the louver 10 of the indoor unit U is pivotally moved by means of the remote controller R, it is possible to recognize the difference between the period of the reversal of the louver 10, and the other periods of time, on the basis of the receiving sounds. Therefore, it is possible to decrease a sense of incongruity when operating the remote controller R. Furthermore, in this preferred embodiment, the control shown in the flowchart of FIG. 13 may be added to the pivotal control of the louver 10 shown in the flowchart of FIG. 12. In FIG. 13, in a case where it is determined at step 93 of FIG. 12 that the louver position of the louver 10 is the louver position d(2) during the "downward movement (n=0) (the position immediately before the reversal illustrated by the solid line in FIG. 4B), or in a case where it is determined that the louver 10 is located at the louver position d(3) during the upward movement" (n=1) (the position immediately before the reversal illustrated by the solid line in FIG. 4C) (step 94), the operation of the louver driving motor M is stopped, so that the louver 10 is stopped at the louver position d(2) or d(3) (step 95). Unless the louver stopping signal is received from the remote controller R, the operation of the louver driving motor M is stopped until a predetermined period of time elapses, so that the position of the louver 10 is maintained at the louver position d(2) or d(3) (steps 96 and 97). In a case where the predetermined period of time elapses before no louver stopping signal has been received at step 96, the routine returns to step 78 shown in FIG. 12, the movement of the louver 10 toward the next louver position (the reversal operation shown in FIG. 4C) is started (step 90 of FIG. 12). On the other hand, when the louver stopping signal is received at step 96 before the predetermined period of time elapses at step 97, the routine returns to step 70 shown in FIG. 12. Then, unless the operation stopping signal (step 73) or the louver moving signal (step 77) is received, as shown in FIG. 12, the operation is continued while the position of the louver 10 is maintained at the louver position d(2) immediately before the reversal (during the "downward movement" (n=0)) or at the louver position d(3) (during the "upward movement" (n=1). According to the aforementioned control shown in the flowchart of FIG. 13, while the operation of the louver driving motor M is stopped for the predetermined period of time immediately before the reversal operation of the louver 10 shown in FIG. 4C, it is possible to command to stop the louver driving motor M by means of the remote controller (the manually operable means) R (step 96). Thus, when a user tries to move and stop the louver 10 at the pivotal position immediately before the reversal operation (i.e., the louver position d(2) (during the "downward movement" (n=0)) or at the louver position d(3) (during the "upward movement" (n=1))) by means of the remote controller R, it is possible to prevent the reversal operation of the louver 10 from being carried out due to the delay of operation of the remote controller R, so that it is possible to prevent the situation that the louver 10 can not be stopped at the aforementioned position. Therefore, it is possible to easily carry out the stopping operation of the louver 10 at a position immediately before the reversal, by means of the remote controller R. [Second Preferred Embodiment] FIGS. 14 through 18 show the second preferred embodiment of the present invention. Furthermore, in this preferred embodiment shown in FIGS. 14 through 18, the same reference numbers are used for the same elements as those of the aforementioned first preferred embodiment shown in FIGS. 1 through 13, and the descriptions thereof are omitted. As shown in FIG. 14, an indoor unit U' for an air conditioning system in this preferred embodiment has an outlet port 1, and two horizontally extending louvers 20 and 30 for vertically changing the discharge direction of a conditioned air. The louvers 20 and 30 are pivotally movable or turnable about pivotal axes C1 and C2 parallel to each other, respectively. The louver 20 is arranged on the side of a rear wall 2b of a discharge passage 2 and has substantially the same shape as that of the louver 10 in the aforementioned first preferred embodiment. On the other hand, the louver 30 is arranged on the side of a front wall 2a of the discharge passage 2 and has a cross section of a substantially plate-like shape. The louver 30 has one end 31 and the other end 32. The louvers 20 and 30 are driven by means of louver driving motors M1 and M2, respectively (see FIG. 15). Similar to the louver driving motor M in the aforementioned first preferred embodiment, the louver driving motors M1 and M2 may be step motors which are capable of detecting the pivotal positions of the louvers 20 and 30 by means of a control unit 27, respectively. The pivotal axes C1 and C2 face the side of one end 21 of the louver 20 and a substantially central portion of the louver 30, respectively, and are shifted from the louvers 20 and 30 in the thickness directions thereof, respectively. In order to improve the appearance of the indoor unit U', when the operation of the air conditioning system is stopped, the louver 30 is pivotally moved to a position (a stopped position or a closing position shown in FIG. 14), at which the outlet port 1 is partially closed by the louver 30 along a front surface 3a of a front panel 3, and the louver 20 is pivotally moved to a position (a stopped position or a closing position shown in FIG. 14), at which the outlet port 1 is partially closed by the louver 20 substantially along an imaginary surface S connecting the other end 32 or the lower end 32 of the louver 30 to a bottom surface 3b of the front panel 3 and which is arranged above the imaginary surface S, by means of the louver driving motors M1 and M2, respectively. A plate-like supporting member 35 for supporting thereon the louvers 20 and 30 at the central portion thereof with respect to the axial directions of the pivotal axes C1 and C2 is provided in the discharge passage 2. The supporting member 35 comprises a base portion 36, both ends of which are supported on the front wall 2a and the rear wall 2b, a supporting portion 37 extending from a substantially central portion of the base portion 36 in a forward and downward direction, and a supporting portion 38 extending along the front wall 2a from the base portion 36 on the side of the front wall 2a in a forward and downward direction. In addition, the louvers 20 and 30 are provided with mounting plates 23 and 33 corresponding to the supporting portions 37 and 38 of the supporting member 35 on the side of the pivotal axes C1 and C2, respectively. The tip portions of the mounting plates 23 and 33 are pivotally connected to the tip portions of the supporting portions 37 and 38 of the supporting member 35 at the positions of the pivotal axes C1 and C2, respectively. As shown in FIG. 16, similar to the aforementioned first preferred embodiment, the air conditioning system in this preferred embodiment has a remote controller R. The indoor unit U' has a receiving unit 25, a receiving sound producing means 26 and a control unit 27, which are the same as those of the indoor unit U in the aforementioned first preferred embodiment. In addition, the indoor unit U' has a drive circuit 28a for driving the louver driving motors M1 and M2. The drive circuit 28a is designed to selectively drive any one of the louver driving motors M1 and M2 by adding a relay circuit to the same circuit as that of the drive circuit 28 in the aforementioned first preferred embodiment. The control unit 27 is designed to drive any one of the louver driving motors M1 and M2 via the drive circuit 28a in response to a remote control signal of the remote controller R received by the receiving unit 25, so as to independently cause the pivotal movement of the louvers 20 and 30. Referring to FIGS. 17 and 18, the relationship between the pivotal movements of the louvers 20 and 30 and the discharged direction of the conditioned air will be described below. First, as shown in FIG. 17B, similar to the louver 10 in the aforementioned first preferred embodiment, the louver 20 is pivotally movable in a range of about 180 degrees, via the aforementioned stopped position or the closing position, between a position A (see the louver 20 illustrated by the two-dot chain lines in Fig. 17B) and a position B (see the louver 20 illustrated by the solid lines in Fig. 17B). When the louver 20 is located at the position A, the one end 21 of the louver 20 is directed toward the upstream of the conditioned air, and the surfaces 20a,20b of the louver 20 is substantially parallel to the direction of the conditioned air flowing through the discharge passage 2, and when the louver 20 is located at the position B, the other end 22 of the louver 20 is directed toward the upstream of the conditioned air, and the surfaces 20a, 20b of the louver 20 is substantially parallel to the direction of the conditioned air flowing through the discharge passage 2. On the other hand, the louver 30 is pivotally movable in a range of about 130 degrees between a substantially vertical position (position G), at which the other end 32 is directed toward the upstream of the conditioned air as shown in FIG. 17B, and the stopped position or the closing position shown in FIG. 14. That is, the louver 20 is turnable in the two opposite directions from its closing position, and the louver 30 is turnable in only one direction from its closing position. Furthermore, the supporting member 25 is formed so as not to interfere with the pivotal movements of the louvers 20 and 30. In this preferred embodiment, in a case where the discharge direction of the conditioned air is changed from the forward direction to the downward direction (during the "downward movement" of the louver 20), the louvers 20 and 30 are pivotally moved in accordance with the following route. (1) First, when the louver 20 is located at the position A and the louver 30 is located at a substantially horizontal position (i.e., position E, see the two-dot chain line of Fig. 17A), a conditioned air is discharged from the outlet port 1 in a slightly upward and forward direction (see sign e of FIG. 18). From this state, when the one end 31 or the front end of the louver 30 is pivotally moved downwards, the louver 30 is moved to the position G to change the discharge direction of the conditioned air from the slightly upward and forward direction to a forward and downward direction (see FIG. 17A and signs e and f of FIG. 18). (2) From this state, when the one end 21 or the front-lower end of the louver 20 is pivotally moved upwards by about 180 degrees, the louver 20 is located at a position B so that the positions of the one end 21 and the other end 22 of the louver 20 are, substantially, mutually exchanged (see arrow γ of FIG. 17B). In this case, the discharge direction of the conditioned air after the reversal (turning over movement) is changed to a slightly lower position than that before the reversal (see the two-dot chain line of FIG. 17C, and sign g of FIG. 18). (3) From this state, when the other end 22 or the front-lower end of the louver 20 is pivotally moved downwards, the louver 20 is moved to a substantially vertical position (position B') to change the discharge direction of the conditioned air from the forward and downward direction to the downward and slightly rearward direction (toward the wall surface) (see FIG. 17C, and signs g and of FIG. 18). In the opposite case, i.e., in a case where the discharge direction of the conditioned air is changed from the downward direction to the forward direction (during the "upward movement" of the louver 20), the louvers 20 and 30 are pivotally moved in accordance with the opposite pivotal route to the aforementioned pivotal route. Furthermore, a method for changing the pivotal positions of the louver 20 and 30 by means of the remote controller (the manually operable means) R in this preferred embodiment is the same as that in the flowchart of FIG. 12 in the aforementioned first preferred embodiment, except that the assignments of the louver positions d(m) are carried out as follows. That is, in this preferred embodiment, m=1 is assigned to the state that the louver 30 is located at the position E illustrated by the two-dot chain line in FIG. 17A, m=2 is assigned to the state that the louver 30 is located at the position G illustrated by the solid line in FIG. 17a, m=3 is assigned to the state that the louver 20 is located at the position B illustrated by the solid line in FIG. 17b, and m=4 is assigned to the state that the louver 20 is located at the position B' illustrated by the solid line in FIG. 17c. In addition, the louver positions d(0) shows the aforementioned closing positions or the stopped positions of the louver 20 and 30 (see FIG. 14). According to the aforementioned preferred embodiment, it is possible to more widely and effectively change the discharge direction of the conditioned air than the first preferred embodiment, by pivotally moving the louver 20, which is substantially the same as the louver 10 in the first preferred embodiment shown in FIGS. 1 through 13, and the louver 30, respectively (see the comparisons of FIGS. 4 and 17, and FIGS. 5 and 18). Therefore, it is possible to improve the performance of an air conditioning system without spoiling the appearance of an indoor unit when the operation is stopped. [Third Preferred Embodiment] FIGS. 19 through 21 show the third preferred embodiment of an indoor unit according to the present invention. In this preferred embodiment shown in FIGS. 19 through 21, in a case where the direction of a conditioned air discharged from an indoor unit U' is changed between a downward direction and a forward direction, the undermentioned pivotal routes of louvers 20 and 30 are different from those in the aforementioned second preferred embodiment (FIGS. 17 and 18). With respect to other constructions, this preferred embodiment is the same as the aforementioned second preferred embodiment shown in FIGS. 14 through 16. In this preferred embodiment, in a case where the direction of the conditioned air discharged from the indoor unit U' is changed from the forward direction to the downward direction (during the "downward movement" of the louver 20), the louvers 20 and 30 are pivotally moved in the following route. (1) First, similar to the aforementioned second preferred embodiment shown in FIG. 17A, when one end 31 or the front end of the louver 30 is pivotally moved downwards from a state wherein the louver 20 is located at position A and the louver 30 is located at position E, the louver 30 moves to position G to change the discharge direction of the conditioned air from a slightly upward and forward direction to a forward and downward direction (see FIG. 19A, and signs e and f of FIG. 20). (2) From this state, when the one end 31 or the lower end of the louver 30 is pivotally moved upwards, the louver 30 returns to the position E (see FIG. 19B). Then, when one end 21 or the front-lower end of the louver 20 is pivotally moved upwards by about 180 degrees to be reversed (see arrow γ of FIG. 19C), the louver 20 moves to position B. In this case, the discharge direction of the conditioned air is divided into a forward direction defined by the louver 30 (see the two-dot chain line of FIG. 19D) and a forward and downward direction defined by the louver 20. The discharge direction defined by the louver 20 is inclined slightly downwards (see the solid line of FIG. 19D and sign i of FIG. 20) in comparison with the direction illustrated by the solid line of FIG. 19A (see sign f of FIG. 20). (3) From this state, when the one end 31 or the front end of the louver 30 is pivotally moved downwards, the louver 30 moves to the position G again, to change the discharge direction of the conditioned air defined by the louver 30 from the forward direction to a direction parallel to the discharge direction defined by the louver 20 inclined in the forward and downward direction (see the solid line of FIG. 19D and sign j of FIG. 20). (4) From this state, when the other end 22 or the front-lower end of the louver 20 is pivotally moved downwards, the louver 20 moves to position B' to change the discharge direction of the conditioned air from the forward and downward direction to the downward and slightly rearward direction (toward the wall surface) (see FIG. 19E and signs j through h of FIG. 20). On the other hand, in a case where the discharge direction of the conditioned air is changed from the downward direction to the forward direction (during the "upward movement" of the louver 20), the louvers 20 and 30 are pivotally moved in the opposite pivotal routes to the aforementioned pivotal routes, respectively. Referring to the flowchart of FIG. 21, a method for changing the pivotal positions of the louvers 20 and 30 by means of the remote controller (the manually operable means) R in this preferred embodiment will be described below. Furthermore, in the flowchart of FIG. 21, the same reference numbers are used for the same steps as those in the flowchart of FIG. 12 in the aforementioned first preferred embodiment, and the descriptions thereof are omitted. In FIG. 21, the assignments of the respective louver positions f(m) are set as follows. That is, m=1 is assigned to the state that the louver 30 is located at the position E illustrated by the two-dot chain line in FIG. 19A, m=2 is assigned to the state that the louver 30 is located at the position G illustrated by the solid line in FIG. 19A, m=3 is assigned to the state that the louver 20 is located at the position B illustrated by the solid line in FIG. 19B, m=4 is assigned to the state that the louver 20 is located at the position B illustrated by the solid line in FIG. 19C, m=5 is assigned to the state that the louver 30 is located at the position G illustrated by the solid line in FIG. 19D, and m=6 is assigned to the state that the louver 20 is located at the position B' illustrated by the solid line in FIG. 19E. The louver positions f(0) show the stopped positions or the closing positions of the louvers 20 and 30 (see FIG. 14). In addition, n=0 means the "downward movement" of the louver 20, and n=1 means the "upward movement" of the louver 20. At step 76' of Fig. 21 corresponding to step 76 of FIG. 12, for example, m=5 is set in the heating operation mode, and m=1 is set in the cooling operation mode. At step 74' of Fig. 21 corresponding to step 74 of FIG. 12, the louvers 20 and 30 are moved to the stopped positions f(0). At step 79' of Fig. 21 corresponding to step 79 of FIG. 12, in and after the second loop it is determined that m=6 after the louvers 20 and 30 reach the louver positions f(6) during the downward movement (n=0), so that n=1 (during the upward movement) is set at step 80 and m=6-1=5 is set at step 83. That is, the movement of the louvers 20 and 30 are changed from the "downward movement" (n=0) to the "upward movement" (n=1). At steps 84' and 86' of Fig. 21 corresponding to steps 84 and 86 of FIG. 12, m=3 and m=4 are substituted for m=2 and m=3 at steps 84 and 86 of FIG. 12, respectively. Because, the reversal (turning over movement) of the louver 10, in the aforementioned first preferred embodiment, occurs when the louver 10 is changing its own position from the position d(2) to the position d(3) during the "downward movement" (n=0) of the louver 10 and when the louver 10 is changing its position from the position d(3) to the position d(2) during the "upward movement" (n=1) of the louver, however, the reversal of the louver 20, in this preferred embodiment, occurs when the louver 20 is changing its own position from the position f(3) to the position f(4) during the "downward movement" (n=0) and when the louver 20 is changing its own position from the position f(4) to the position f(3) during the "upward movement" (n=1). For the same reason, at step 92' of Fig. 21 corresponding to step 92 of FIG. 12, m=4 and m=3 are substituted for m=3 and m=2 at step 92 of FIG. 12, respectively. Furthermore, steps 93' and 94' of Fig. 21 are the same as steps 93 and 94 of FIG. 12, except that the louver positions f(m) are substituted for the louver positions d(m) at steps 93 and 94 of FIG. 12. With this construction, the operation of this preferred embodiment will be described below. In this preferred embodiment, the pivotal route of the louver 30 with respect to the louver 20 is different from that in the aforementioned second preferred embodiment shown in FIGS. 17 and 18, so that it is possible to increase the area of the conditioned air discharged in the forward and downward direction to a wider area than that in the aforementioned second preferred embodiment (see FIG. 19D, and the comparison of signs f ∼ g of FIG. 18 and signs f ∼ i ∼ j of FIG. 20). Furthermore, similar to at step 76 or 74 in the flowchart of FIG. 12 in the aforementioned first preferred embodiment, at step 76' or 74' in the flowchart of FIG. 21 in this preferred embodiment, the pivotal speeds of the louvers 20 and 30 are set to be three times as large as the usual pivotal speeds when the louvers 20 and 30 are automatically moved. In addition, similar to the flowchart of FIG. 12 in the aforementioned first preferred embodiment, an additional control corresponding to the flowchart of FIG. 13 may be added to the pivotal control of the louvers 20 and 30 shown in the flowchart of FIG. 21 in this preferred embodiment. While the indoor unit U has been provided with a single louver 10 in the aforementioned first preferred embodiment and the indoor unit U' has been provided with two louvers 20 and 30 in the aforementioned second and third preferred embodiments, an indoor unit may be provided with three louvers or more including one or two louvers which are the same as the louvers 10, 20 and 30. [Fourth Preferred Embodiment] FIG. 22 shows the fourth preferred embodiment of the present invention. In this preferred embodiment, an inspection control shown in FIG. 22 is added to the pivotal control of the louver 10 in the aforementioned first preferred embodiment (see FIGS. 12 and 13). Other constructions are the same as those in the first preferred embodiment shown in FIGS. 1 through 13. In FIG. 22, when it is determined at step 98 that the inspecting input means 29 shown in FIG. 6 is turned on, the pivotal control of the louver 10 in an inspection mode is executed at step 99. In the inspection mode at step 99, the louver 10 is sequentially moved over the whole pivotal area at a pivotal speed three times as large as the usual pivotal speed in order to verify the operation of the louver 10. On the other hand, when it is determined at step 98 that the inspecting input means 29 is not turned on, the pivotal control of the louver 10 in the usual mode shown in FIG. 12 (and FIG. 13) is carried out. With this construction, the advantages of this preferred embodiment will be described below. According to this preferred embodiment, since the pivotal speed of the louver 10 pivotally moved in response to the input of the inspecting input means 29 is higher than the usual pivotal speed of the louver 10 pivotally moved in response to the louver moving signal of the remote controller R (except for the reversal of the louver 10), it is possible to decrease the time required to pivotally move the louver 10 in response to the input of the inspecting input means 29 while maintaining the usual pivotal speed of the louver 10 pivotally moved by means of the remote controller R at a low pivotal speed. Therefore, it is possible to quickly carry out the operation for verifying the movement of the louver 10 in the inspection mode based on the input of the inspecting input means 29, and it is also possible to easily carry out the positioning of the pivotal position of the louver 10 by means of the remote controller R. As mentioned above, when the output frequency of the energizing pulse applied to the louver driving motor (the step motor) M is increased in order to change the pivotal speed of the louver 10 to be three times as large as the usual pivotal speed, the torque of the louver driving motor (the step motor) M is decreased. Therefore, it is possible to detect a product wherein the louver 10 does not move in the state that the torque of the louver driving motor M is decreased (i.e., an imperfect product wherein the louver 10 is difficult to operate), in the inspection before shipping the product. Furthermore, the indoor unit U' in the aforementioned second preferred embodiment shown in FIG. 16 may be provided with the same inspecting input means 29 as that shown in FIG. 6, and the aforementioned inspecting control shown in the flowchart of FIG. 22 may be added to the pivotal control (FIG. 12) of the louvers 20 and 30. In addition, the aforementioned inspecting control shown in the flowchart of FIG. 22 may be added to the pivotal control (FIG. 21) of the louvers 20 and 30 in the aforementioned third preferred embodiment. Desired shapes and arrangements of a plurality of louvers of the indoor unit, which has the same plurality of louvers as those in the aforementioned second through fourth preferred embodiments and wherein the movements of the respective louvers are different from each other, will be described below. When the louvers 20 and 30 are located at the stopped positions, a gap x is formed between the louvers 20 and 30 in forward and rearward directions as shown in FIG. 23. This gap x is set to be a small gap as long as the louvers 20 and 30 do not collide with each other when the louvers 20 and 30 are pivotally moved. Since the gap x is so set, the louvers 20 and 30 can be pivotally moved so that the pivotal loci thereof do not cross each other, in other words, the louvers 20, 30 are turned without causing interference of pivotal loci of the louvers 20,30, as shown in FIG. 24. In addition, as shown in FIG. 23, a gap y is formed between the louver 20 and the rear wall 2b of the discharge passage 2. This gap y is set to be small as long as the louver 20 does not collide with the rear wall 2b of the discharge passage 2 when the louver 20 is pivotally moved. It is possible to set the gap y to be a very small gap in accordance with the specific shapes and mounting structures of the louvers 20 and 30. As shown in FIG. 23, when the louver 30 is located at the stopped position or the closing position, the outer surface 30b of the louver 30 is substantially parallel to an imaginary extended surface of the outer surface of the front panel 3 surrounding the outlet port 1. That is, the outer surface 30b of the louver 30 is a slightly curved surface which substantially corresponds to an imaginary extended surface S1 (illustrated by the two-dot line in FIG. 23) extended from the front surface 3a of the front panel 3 while maintaining the curvature thereof, so that the outer surface 30b corresponds to the imaginary extended surface S1. Furthermore, as shown in the fifth through seventh preferred embodiments which will be described later, in a case where the air conditioning system has a function forming a "short circuit", the curve of the louver 30 is preferably small. When the louver 30 is located at the stopped position, no gap is formed between the louver 30 and the front wall 2a of the discharge passage 2, so that the louver 30 substantially contacts the front wall 2a. That is, the front end 31 of the louver 30 substantially contacts the front periphery of the outer port 1. Such an arrangement is permitted since the louver 30 is pivotally moved only one direction or counterclockwise direction of Fig. 23 from the stopped position. As shown in FIG. 23, when the louver 20, which is located behind the louver 30 and wherein the front end 21 side thereof is curved toward the pivotal axis C1, is located at the stopped position, the rear end 22 side of the outer surface 20b thereof substantially corresponds to the imaginary extended surface of the outer surface of the front panel 3 surrounding the outlet port 1. That is, the rear end 22 side of the outer surface 20b of the louver 20 is formed so as to substantially correspond to the imaginary extended surface S2 (illustrated by the two-dot chain line in FIG. 23) extended from the lower surface 3b of the front panel 3 while maintaining the curvature thereof, so that the outer surface 20b of the louver 20 corresponds to the imaginary extended surface S2 so as to be associated therewith for forming a smooth curved surface. Therefore, it is possible to improve the appearance of the indoor unit when it is stopped. When the louvers 20 and 30 are located at the stopped positions, the rear end 32 of the louver 30 located in front of the louver 20 is located below the front end 21 of the louver located behind the louver 30. That is, as shown in FIG. 23, the louvers 20 and 30 are arranged so as to overlap with each other at a vertical interval of z. Therefore, when the indoor unit is viewed substantially from the front, it is not possible to recognize the gap between the louvers 20 and 30 with the naked eye, so that the appearance of the indoor unit is not spoiled even if the gap x is formed between the louvers 20 and 30. Furthermore, in a case where the louver 20 is curved, the space between the louvers 20 and 30 can be substantially wider than that in an indoor unit wherein the louver 20 is not curved (see FIG. 25). Therefore, in a case where the louvers 20 and 30 are located at positions near the stopped positions and where the indoor fan 8 is in the operation state or is not completely stopped, such as immediately before the operation of the air conditioning system is stopped or immediately after the operation thereof is started, it is possible to prevent the surging of the discharged flow, which is caused by blocking the conditioned air by the louvers 20 and 30. Thus, it is possible to prevent noises from being produced due to the surging. Furthermore, the shape of the louver 20 should not be limited to that shown in FIG. 23, but a louver 20 having a smoothly curved cross section shown in FIG. 25 may be used. That is, the whole outer surface 20b of the louver 20 may be curved so as to correspond to an imaginary extended surface S2 (illustrated by the two-dot chain line in FIG. 25), so that the whole outer surface 20b of the louver 20 may correspond to the imaginary extended surface S2 when the system is stopped. With this construction, since the whole outer surface 20b of the louver 20 and the whole outer surface 30b of the louver 30 correspond to the outer surface of the front panel 3, it is possible to further improve the appearance of the indoor unit. As shown in FIG. 26, the shape of the front panel 3 may be changed and the louver 30 may be located slightly behind the front surface 3a of the front panel 3. While the front louver 30 has been pivotally moved counterclockwise from the stopped position in the aforementioned preferred embodiment, the louver 30 may be pivotally moved clockwise (see the arrow in FIG. 27) from the stopped position (illustrated by the solid line in FIG. 27). In this case, as shown in FIG. 27, the lower end of the front surface 3a of the front panel 3 is formed with a projecting portion 3c. As shown in FIG. 27, the tip portion of the projecting portion 3c extends inside of the pivotal locus r of the rear end 32 of the louver 30, so that the louver 30 is designed to collide with the projecting portion 3c when it is pivotally moved counterclockwise to the position illustrated by the two-dot chain line in FIG. 27. However, the louver driving motor M2 for driving the louver 30 is designed to prevent the louver 30 from being pivotally moved to the position at which the louver 30 collides with the projecting portion 3c. In addition, the front end 32 of the outer surface 30b of the louver 30 is designed to contact the inner surface of the projecting portion 3c when it is stopped. While the indoor unit has been provided with two louvers 20 and 30 in the aforementioned preferred embodiment, the distance between the louvers 20 and 30 may be increased, and an additional louver having the same shape and function as that of the louver 20 may be provided between the louvers 20 and 30. In this case, the rear end 32 of the louver 30 may be located below the front end edge of the additional louver behind the louver 30, and the rear end edge of the additional louver may be located below the front end 21 of the louver 20 behind the additional louver. The aforementioned shapes and arrangements of the louvers 20 and 30 may not be only applied to the indoor unit wherein the louvers 20 and 30 are driven by the louver driving motors M1 and M2, but they may be also applied to an indoor unit wherein at least one of the louvers 20 and 30 is manually moved. As mentioned above, since the plurality of louvers are arranged so that their pivotal loci do not cross each other, it is possible to prevent the louvers from colliding with each other. Therefore, even if the pivotal controls of the louvers shown in the second through fourth preferred embodiments are carried out, it is not required to carry out any complicated controls in order to prevent the louvers from colliding with each other, so that it is possible to more easily provide an indoor unit having a good discharge characteristic for a conditioned air. In addition, even if the louvers are manually operated by a user's hand, it is possible to prevent the louvers and their supporting portions from being damaged. [Fifth Preferred Embodiment] Referring to FIGS. 28 through 29, the fifth preferred embodiment of the present invention will be described below. As shown in FIG. 29, the front and upper surfaces of an indoor unit 101 mounted on the upper portion of the inner wall of a room are provided with inlet ports 102 and 103 for sucking an indoor air, and the bottom surface thereof is provided with an outlet port 104 for discharging a conditioned air. The indoor unit 101 has therein a discharge passage 105 for introducing the conditioned air into the outlet port 104. Inside of the inlet ports 102 and 103, a dustproof and deodorizing filter 106 is provided. Inside of the filter 106, a main indoor heat exchanger 107 and an auxiliary indoor heat exchanger 108 are provided. Inside of the heat exchangers 107 and 108, a cross-flow or transverse type indoor fan 109 is provided. The main indoor heat exchanger 107 is divided into a first heat exchanger 107a and a second heat exchanger 107b. The first heat exchanger 107a faces the front inlet port 102 and the second heat exchanger 107b faces the upper inlet port 103, so that the first and second heat exchangers 107a and 107b are arranged in the form of reversed V-shape to surround the indoor fan 109. The auxiliary heat exchanger 108 is arranged between the second heat exchanger 107b and the inlet port 103. An electric heater 117 and a water guard member 118 are provided between the first and second heat exchangers 107a, 107b and the indoor fan 109. The electric heater 117 serves to heat air passing through the heat exchangers 107a and 107b if necessary. The water guard member 118 serves to prevent the drain from being dropped directly to the electric heater 117 from the first and second heat exchangers 107a and 107b. Drain receivers 119 are provided below the first and second heat exchangers 107a and 107b and below the auxiliary indoor heat exchanger 108, respectively. Although the radiating fin of the first heat exchanger 107a contacts the radiating fin of the second heat exchanger 107b, a gap is formed between the radiating fin of the second heat exchanger 107b and the radiating fin of the auxiliary indoor heat exchanger 108, so that both radiating fins are not brought into contact with each other, i.e., thermally isolated from each other. When the indoor fan 109 is rotated, the indoor air is sucked into the indoor unit 101 via the inlet ports 102 and 103. The air sucked from the inlet port 102 passes through the filter 106, and then, passes through the first heat exchanger 107a to flow toward the indoor fan 109. The air sucked from the inlet 103 passes through the filter 106, and thereafter, passes through the auxiliary indoor heat exchanger 108, and then, passes through the second heat exchanger 107b to flow toward the indoor fan 109. At a location at which the discharge passage 105 faces the outlet port 104, there is provided with a plurality of vertically extending louvers 110 driven by a drive motor 110M shown in FIG. 29 for horizontally changing the discharged direction of the conditioned air. Downstream of the vertically extending louvers 110, a pair of horizontally extending louvers 150 and 111 are provided. The horizontally extending louvers 150 and 111 are driven by a drive motor 111M shown in FIG. 29 to be pivotally moved about a pivotal axis 111b supported on a supporting stay 111a, for vertically changing the discharged direction of the conditioned air. Referring to FIG. 29, a refrigerating cycle of the fifth preferred embodiment of an air conditioner 100 according to the present invention will be described below. As shown in FIG. 29, an outdoor heat exchanger 123 is connected to a discharge port of a compressor 121 via a four-way valve 122. An expansion mechanism, e.g., an electric expansion valve 124, is connected to the outdoor heat exchanger 123. One end of the auxiliary indoor heat exchanger 108 is connected to the electric expansion valve 124, and the other end of the auxiliary indoor heat exchanger 108 is connected to the main indoor heat exchanger 107 (the first and second heat exchangers 107a and 107b). The main indoor heat exchanger 107 is also connected to an inlet port of the compressor 121 via the four-way valve 122. On the other hand, as shown in FIG. 29, a heat exchanging pipe on the outlet side of the auxiliary indoor heat exchanger 108 and a heat exchanging pipe at the intermediate part of the first heat exchanger 107a are provided with heat exchanger temperature sensors 113 and 114, respectively. In addition, an indoor temperature sensor 115 is mounted on a passage for sucking an indoor air between the inlet port 102 and the main indoor heat exchanger 107. In addition, an outdoor fan 125 is provided near the outdoor heat exchanger 123 for supplying an outdoor air to the outdoor heat exchanger 123. A commercial alternating-current power supply 130 is connected to an inverter circuit 131, speed control circuits 132, 133 and a control unit 140. The control unit 140 is also connected to the inverter circuit 131, the speed control circuits 132, 133, the vertically extending louver driving motor 110M, the horizontally extending louver driving motor 111M, the heat exchanger temperature sensors 113, 114, the indoor temperature sensor 115, the electric heater 117, the four-way valve 122, the electric expansion valve 124 and the receiving unit 141. The inverter circuit 131 is designed to rectify a supply voltage to convert the rectified supply voltage into an alternating current of a frequency and voltage corresponding to the command of the control unit 140, to supply the alternating current as a drive power to the drive motor for the compressor 121. The speed control circuit 132 is designed to control a supply voltage, which is supplied to an outdoor-fan driving motor 125M, to set the capacity of the outdoor fan 125 in accordance with the command of the control unit 140. The speed control circuit 133 is designed to control a supply voltage, which is supplied to an indoor-fan driving motor 109M, to set the capacity of the indoor fan 109 in accordance with the command of the control unit 140. The receiving unit 141 is designed to receive an infrared signal transmitted from a remote controller 142 operated by a user. With this construction, when the air conditioner 100 in this preferred embodiment is used for cooling or dehumidifying, a refrigerating cycle illustrated by the arrows of solid lines in FIG. 29 is formed, wherein the refrigerant discharged from the compressor 121 sequentially flows from the four-way valve 122 to the main indoor heat exchanger 107 via the outdoor heat exchanger 123, the electric expansion valve 124 and the auxiliary indoor heat exchanger 108, and then, the refrigerant discharged from the main indoor heat exchanger 107 returns to the compressor 121 via the four-way valve 122. That is, the outdoor heat exchanger 123 serves as a condenser, and the main indoor heat exchanger 107 and the auxiliary indoor heat exchanger 108 serve as an evaporator. On the other hand, when heating, the four-way valve 122 is switched, so that a cycle illustrated by the arrows of broken lines in FIG. 29 is formed, wherein the refrigerant discharged from the compressor 121 sequentially flows from the four-way valve 122 to the outside heat exchanger 123 via the main indoor heat exchanger 107, the auxiliary indoor heat exchanger 108 and the electric expansion valve 124, and then, the refrigerant discharged from the outside heat exchanger 123 returns to the compressor 121 via the four-way valve 122. That is, the main indoor heat exchanger 107 and the auxiliary indoor heat exchanger 108 serve as a condenser, and the outdoor heat exchanger 123 serves as an evaporator. As shown in FIG. 28, when the air conditioner 100 in this preferred embodiment is used for dehumidifying, the horizontally extending louvers 150 and 111 are pivotally moved by means of the horizontally extending louver driving motor 111M, so that the downstream end portions of the louvers 150 and 111 are arranged above a horizontal line. In addition, the vertically extending louvers 110 are set to be located at the center in the longitudinal direction by means of the drive motor 110M. Moreover, the indoor fan 109 is driven at a low speed. Thus, a conditioned air flow W, wherein a conditioned air is sucked into an inlet port 102 immediately after being discharged from the outlet port 104, is formed (this flow route will be referred to as a "short circuit"). That is, most of the conditioned air discharged from the outlet port 104 passes near the indoor unit 101 to be sucked into the outlet port 104, so that the conditioned air does not reach the central portion of the room. Therefore, it is possible to continue to dehumidify without causing a cold conditioned air to reach the central portion of the room, and to accomplish a comfortable dehumidification without giving a cold wind feeling. Furthermore, although a part of indoor air is continuously sucked into the indoor unit 101 by forming the "short circuit", the moisture diffusing rate is sufficiently great, so that it is possible to surely dehumidify the indoor air. Referring to FIGS. 28 and 30, this preferred embodiment of an air conditioner 100 of the aforementioned construction, particularly the indoor unit 101, according to the present invention, will be described below. As shown in FIGS. 28 and 30, the upper surface 151 of the front louver 150 on the side of the inlet port 102, which is one of the pair of horizontally extending louvers 150 and 111 provided in the outlet port 104, is provided with a projection 152 of a substantially triangular cross section, which projects from the end portion of the upper surface 151 downstream of the conditioned air so as to increase the thickness of the louver 150 and which extends in the whole length. The projection 152 serves to form a wind deflecting surface 153 for changing the discharged direction of the conditioned air. Furthermore, an extension L of the wind deflecting surface 153 passes downstream of an edge 104a of the outlet port 104 on the side of the inlet port 102 to reach the front surface of the inlet port 102. Therefore, the wind deflecting surface 153 may be located on the upper surface 151 of the louver 150 upstream or downstream of the conditioned air, with respect to a parting line 104b of the edge 104a of the outlet port 104, i.e., an imaginary extended surface of the front panel. That is, as illustrated by the black-painted arrows in FIG. 30, the conditioned air flow W1 flowing along the upper surface 151 of the louver 150 is deflected to flow toward the inlet port 102. On the other hand, as illustrated by the white-painted arrows in FIG. 30, the conditioned air flow W2 flowing along the lower surface 152 of the louver 150 flows without being deflected. Since the wind deflecting surface 153 is formed by the projection 152 which projects by increasing the thickness of the louver 150, the conditioned air flow W1 flowing along the upper surface 151 of the louver 150 is completely separated from the conditioned air flow W2 flowing along the lower surface 154 of the louver 150, on the downstream side of the louver 150, so that they are not attracted to each other to be combined with each other. In this preferred embodiment, the louver 150 has a plate-like shape over the whole lateral direction. Thus, it is possible to decrease the resistance to the conditioned air in comparison with a louver curved in the lateral directions, so that it is possible to increase the flow rate of the conditioned air flow W1 flowing along the upper surface 151 of the louver 150. Therefore, the flow rate of the conditioned air deflected by the wind deflecting surface 153 to flow in the inlet port 102 is also increased, so that it is possible to surely form the "short circuit". In this preferred embodiment, out of the conditioned air discharged from the outlet port 104, the conditioned air flow W1 flowing along the upper surface 151 of the louver 150 is surely deflected by the wind deflecting surface 153. Therefore, even if the inclined angle of the louver 150 is shifted from an optimum inclined angle when the inclined angle of the louver 150 is controlled to form a "short circuit", it is possible to surely form the "short circuit". [Sixth Preferred Embodiment] Referring to FIG. 31, the sixth preferred embodiment of the present invention will be described below. As shown in FIG. 31, the sixth preferred embodiment of an indoor unit according to the present invention is substantially the same as the indoor unit in the fifth preferred embodiment, except that the shape of a cross section of an outlet cover 160 forming a front wall 104c of an outlet port 104 is different from that in the fifth preferred embodiment (see 160a of FIG. 30). In this preferred embodiment, the outlet cover 160 forming a part of the front wall 104c of the outlet port 104 is formed with a cylindrical curved surface 161 which is convex downwards toward the louver 150. The imaginary extension of the surface 161 extends toward the inlet port 102. Thus, the conditioned air flow W1 flowing along the front wall 104c of the outlet port 104 is gradually deflected as flowing along the curved surface 161 of the outlet cover 160, to flow toward the inlet port 102. At this time, the conditioned air flow W2, which is illustrated by the white-painted arrows in FIG. 31 and which flows a portion apart from the front wall 104c of the outlet port, is attracted by the conditioned air flow W1 deflected by the curved surface 161 to be combined therewith to flow in the inlet port 102. Moreover, the conditioned air flow W3 flowing along the upper surface 151 of the louver 150 is deflected by the wind deflecting surface 153 of the louver 150. That is, in this preferred embodiment, the conditioned air flows W1, W2 and W3 flowing between the front wall 104c of the outlet port 104 and the louver 150 are deflected by the curved surface 161 and the wind deflecting surface 153 to be combined with each other to flow in the inlet port 102. Thus, even if the inclined angle of the louver 150 is shifted from an optimum inclined angle when the inclined angle of the louver 150 is controlled to form a short circuit, it is possible to surely form the short circuit. Furthermore, while the outlet cover 160 forming a part of the front wall 104c of the outlet port 104 has been formed with the curved surface 161 in this preferred embodiment, the front wall 140c of the outlet port 104 may be formed with a curved surface for deflecting the conditioned air flow W. [Seventh Preferred Embodiment] Referring to FIG. 32, the seventh preferred embodiment of the present invention will be described below. This preferred embodiment is substantially the same as the sixth preferred embodiment, except for the shape of a cross section of the louver on the side of the inlet port 102. That is, as shown in FIG. 32, in this preferred embodiment, the thickness of a horizontally extending louver 170 is substantially constant in the flowing direction of the conditioned air. The louver 170 is bent at a location downstream of the center in the lateral direction of the louver 170 so that a downstream end portion 171 of the louver 170 rises toward the inlet port 102 with respect to an upstream end portion 172. The bent point 175 of the louver 170 is located upstream of the center of the louver 170. An upper surface 173 of the downstream end portion 171 serves as a wind deflecting surface for changing the flowing direction of the conditioned air. The wind deflecting surface 173 is formed so that a tangential line L thereof passes downstream of the edge 104a of the outlet port 104 on the inlet port 102 to reach in front of the front surface of the inlet port 102 when the inclined angle of the louver 170 is controlled so as to form a "short circuit". Thus, as illustrated by the black-painted arrows in FIG. 32, the conditioned air flow W1 flowing along the upper wall 172a of the louver 170 is deflected by the wind deflecting surface 173 to flow toward the inlet port 102. On the other hand, as shown in FIG. 32, an outlet cover 180 forming a part of the front wall 104c of the outlet port 104 is provided with a cylindrical curved surface 181, which is convex downwards and toward the louver 170 and which has a curved extension extending toward the inlet port 102. Thus, the conditioned air flow W2 flowing along the front wall 104c of the inlet port is gradually deflected upwards as flowing along the curved surface 181 of the outlet cover 180, to flow toward the inlet port 102. At this time, the lowest end portion 182 of the curved surface 181 is located upstream (on the rear side) of the bent point 175 of the louver 170. Thus, the conditioned air flow W1 deflected by the wind deflecting surface 173 of the louver 170 and the conditioned air flow W2 deflected by the curved surface 181 of the front wall 104c are smoothly discharged from the outlet port 104 without interfering with each other. The flow velocity of the conditioned air flow W2 flowing along the front wall 104c of the outlet port 104 is higher than that of the conditioned air flow W1 flowing along the upper surface 172a of the louver 170. Thus, the conditioned air flow W1 deflected by the wind deflecting surface 173 of the louver 170 is attracted by the conditioned air flow W2 deflected by the curved surface 181 of the front wall 104c, and further deflected to flow toward the inlet port 102. In this preferred embodiment, the upstream portion (the rear side portion), with respect to the bent point 175, of the louver 170 in the lateral directions thereof has a plate-like shape. Thus, it is possible to decrease the resistance to the conditioned air in comparison with a louver curved in whole in the lateral direction, so that it is possible to increase the capacity of the conditioned air flow W1 flowing along the upper wall surface 172a of the louver 170. Therefore, the capacity of the conditioned air deflected by the wind deflecting surface 173 to flow in the inlet port 102 is increased, so that it is possible to surely form a short circuit. In this case, the capacity of the air flow W3 flowing on the side of the reversed surface of the louver 170 is small and the wind velocity is low, so that the conditioned air flow W2 is not attracted by the air flow W3. Therefore, according to this preferred embodiment, since the conditioned air flows W1 and W2 discharged from the outlet port 104 are surely deflected so as to flow toward the inlet port 102, it is possible to surely form a short circuit even if the inclined angle of the louver 170 is shifted from an optimum inclined angle when the inclined angle of the louver 170 is controlled to form the short circuit. When a usual cooling or heating operation is carried out, in a case where the inclination of the louver 170 is controlled so that the discharge direction of the conditioned air is changed from a horizontal direction to an inclined downward direction, it is possible to decrease the ventilation resistance of the louver 170 to cause a smooth air flow. Moreover, in this preferred embodiment, when the louver 170 is pivotally moved to close the outlet port 104 as illustrated by the two-dot chain line of FIG. 32, the surface of the front panel 102a forming the inlet port 102 is parallel to the lower surface 174 of the louver 170, and the end portion 171a of the louver 170 faces the edge 104a of the outlet port 104, so that it is possible to greatly improve the appearance of the indoor unit 101 when the outlet port 104 is closed by the louver 170, i.e., when the operation is stopped. As mentioned above, according to the fifth through seventh preferred embodiments, when the inclined angle of the louver or the pivotal position of the louver is controlled to form a "short circuit", the conditioned air discharged from the outlet port of the indoor unit is deflected by the wind deflecting surface to flow in the inlet port. Therefore, even if the inclined angle of the louver is shifted from the optimum angle, it is possible to surely form the "short circuit". Thus, a cooled conditioned air discharged from the outlet port when the dehumidifying operation of the air conditioning system is carried out, flows from the outlet port to the inlet port without flowing toward the central portion of the room, and circulates between the inlet port, the heat exchanger, the indoor fan and the outlet port, so that it is possible to dehumidify the room without causing a cold wind feeling. Furthermore, the rear louver 111 in the fifth through seventh preferred embodiments is the same as the louver 20 in the second through fourth preferred embodiment. In this case, two louver driving motors are employed for driving the louvers respectively, and the operation of the respective louvers may be controlled in the same manner as that in the second through fourth preferred embodiment.

Claims: An indoor unit for an air conditioning system, comprising: an outlet port (1) for discharging a conditioned air into a room; an inlet port (4) for sucking an air to be conditioned from the room; a discharge passage (2) for allowing the conditioned air to flow in a forward and downward direction toward said outlet port (1); a rear and a front louver (20, 30), provided in said outlet port and arranged adjacent to each other, for vertically changing a discharge direction of said conditioned air, each of said lovers being turnable about a horizontal pivotal axis (Cl, C2), wherein one (20) of the louvers is adapted to turn in opposite two directions from its closing position and the other (30) of the louvers is adapted to turn in only one direction from its closing position, said one (20) of the louvers has a curved cross section with a concave surface (20a) and a convex surface (20b) opposite to said concave surface (20a), and when both said louvers (20, 30) are located at their closing positions at which said louvers (20, 30) substantially closes said outlet port, a gap (x) is formed therebetween so that said louvers (20, 30) are capable of turning without causing interference of pivotal loci of said louvers (20, 30); drive means (M1, M2) for driving said louvers (20, 30) to turn said louvers about said pivotal axes (Cl, C2); and control means (27) for controlling said drive means (M1, M2) to turn said louvers (20, 30), said control means (27) being configured to control one (M1) of said drive means so that said concave surface (20a) of said one (20) of the louvers is directed substantially upwards when conditioned air is to be discharged forwards, and said concave surface (20a) is directed substantially backwards when the conditioned air is to be discharged downwards; characterized in that said one (30) of the louvers being adapted to turn in only one direction is said front louver (30); said other one (20) of the louvers being adapted to turn in opposite two directions and having said curved cross section is said rear louver (20); a rear end edge (32) of said front louver (30) is located below a front end edge (21) of said rear louver (20) when each of said louvers (20, 30) is located at said closing position; and a front edge (33) of said front louver (30) substantially contacts to a front wall (2a) of said outlet port (1) when said front louver (30) is located at said closing position. An indoor unit according to claim 1, wherein: said control means (27) controls said drive means (M1, M2) to turn said rear louver (20) so that said concave surface (20a) is directed substantially upwards when the conditioned air is to be discharged forwards, and said concave surface (20a) is directed substantially backwards when the conditioned air is to be discharged downwards, and when the discharge direction of said conditioned air to be changed between a forward direction and a downward direction, said rear louver (20) is subjected to movement including a usual turning-over movement, during which discharge direction of said conditioned air is continuously changed in accordance with the change of pivotal position of said rear louver (20), and a turning-over movement by which the positions of one end (21) and the other end (22) of the rear louver (20) are mutually exchanged, the turning direction of said turning-over movement being opposite to that of said usual turning-over movement. An indoor unit as set forth in claims 2, wherein said control means (27) controls said drive means (M1) for driving said rear louver (20) so that turning speed, during said turning-over movement, of said rear louver (20) having a curved cross section is higher than turning speed during said usual tuning movement. An indoor unit as set forth in claim 3, wherein said control means (27) controls said drive means (M1) for driving said rear louver (20) so that said rear louver (20) having a curved cross section is stopped for a predetermined period of time immediately before said turning over movement starts. An indoor unit as set forth in claim 3 or 4, further comprising: manually operable means (R) for commanding operation and stop of said drive means to said control means, to move said louvers (20, 30) to optional pivotal positions, and wherein said control means (27) controls said drive means (M1) for driving said rear louver (20) so that said rear louver (20) having a curved cross section is stopped at a position other than said closing position when said control means receives a stopping command from said manually operable means during said turning over movement of said rear louver (20) having a curved cross section. An indoor unit as set forth in any one of claims 2 through 5, wherein said drive means comprises a step motor (M1) for driving said rear louver (20) having exciting coils (Ø1 ∼ Ø4), and wherein said control means changes a rotational speed of said step motor for changing turning speed of said rear louver (20) by switching an exciting system of said step motor between a one-two-phase exciting system and a two-phase exciting system. An indoor unit as set forth in claim 1, further comprising: manually operable means (R) for commanding operation and stop of said drive means (M1, M2) to said control means (27), to turning said louvers (20, 30) to optional pivotal positions, and wherein said control means (27) controls said drive means (M1, M2) so that turning speed of said louvers when automatically causing turning movement of said louvers is higher than turning speed of said louvers when causing turning of said louvers in response to an input at said manually operable means, at least in a part of a turning range of said louvers. An indoor unit as set forth in claim 1, wherein the front louver (150; 170) has a wind deflecting surface (153; 173) for deflecting said conditioned air in a forward and upward direction, said wind deflecting surface being arranged at a downstream end portion, with respect to a flow of conditioned air, of one surface (151, 172a) of said front louver, and wherein said front louver forms a flow of conditioned air toward an inlet port (102) from an outlet port (104) via said wind deflecting surface when said front louver is turned to a predetermined position. An indoor unit as set forth in claim 8, wherein said wind deflecting surface (153; 173) is formed so as to deflect said conditioned air discharged from said outlet port toward the downstream of a peripheral edge (104a) of an outlet port (104) when said flow of conditioned air flowing from said outlet port toward an inlet port (102) is formed. An indoor unit as set forth in claim 8 or 9, wherein an winner wall surface (104c) forming a discharge passage (105) on the side of an inlet port (102) is provided with a curved surface (181) projecting toward said front louver (170), and wherein a lowest end (182) of said curved surface (181) is located upstream of said wind deflecting surface (173) with respect to said flow of conditioned air when said front louver (170) is located so as to form a flow of conditioned air form said outlet port (104) to said inlet port. An indoor unit as set forth in any one of claims 8 to 10, wherein a portion of said louvers upstream of said wind deflecting surface (153; 173), with respect to said flow of conditioned air, has a plate-like shape.

Inventors: HONGO ICHIRO, KAGEYAMA YASUHIRO, KATO SHIGEKI, NIGO TOSHIRO, NUKUSHINA HARUNOBU, OKUDA KENJI, YAMASHITA TETSUJI, HONGO, ICHIRO, KAGEYAMA, YASUHIRO, KATO, SHIGEKI, NIGO, TOSHIRO, NUKUSHINA, HARUNOBU, OKUDA, KENJI, YAMASHITA, TETSUJI
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1997
Main classification: F24F1
IPC codes: F24F1