Applicant: DAIKIN INDUSTRIES, LTD. Title: VENTILATING DEVICE AND AIR CONDITIONER PCT Application No.: PCT/JPO2/10889 TRANSLATION VERIFICATION I hereby verify that the attached papers are a true English translation of the International Application identified above as originally filed. The undersigned declares further that all statements made herein of my own knowledge are true and that all statements made on information and belief are believed to be true. June 11, 2003 Hidetada KATO SPECIFICATION Ventilating device and air conditioner 5 TECHNICAL FIELD The present invention relates to an air conditioner and a ventilating device that is included in an air conditioner, and more particularly, to an air conditioner and a ventilating device comprised of a fan and an air path that connects an outdoor space with an indoor space. 10 BACKGROUND ART Recently, air conditioners and the like have been introduced which include a humidification unit that draws in moisture from the outside air and delivers the moisture to an indoor space. 15 These humidification units has a structure like that disclosed in Japanese Unexamined Patent Application No. 2001-41511, and use a humidification rotor consisting of zeolite to humidify air that is blown into an indoor space by a fan. More specifically, the air that is blown into the indoor space is humidified by having the humidification rotor absorb moisture in the air, a heater is used to release the moisture 20 from the humidification rotor, and then this released moisture is added to air that is blown into the indoor space. Thus, a comfortable relative humidity can be maintained in an indoor space even during winter, when the air is dry, because the humidification unit in the air conditioner can supply humidified air to the indoor space. In addition, the 1 aforementioned humidification unit includes a fan that functions to supply air drawn in from outdoors to an indoor space, and thus can use this function to exchange indoor air with outdoor air. The humidification unit that draws in air from outdoors and humidifies it (or 5 leaves it as is), and then supplies that air to an indoor space by means of the fan, also includes the aforementioned air exchange function. Outdoor air is generally cleaner than indoor air, and thus if outdoor air is blown into an indoor space with the fan of the humidification unit, the indoor air will be exchanged with the outdoor air and thus become cleaner. 10 However, if the indoor air has become seriously polluted due to cigarette. smoke and the like, it will take time to push the polluted indoor air outside through gaps in the room with an air exchange method that blows in outdoor air into the indoor space. In contrast, although it is believed that a ventilation fan installed separately from the air conditioner can effectively discharge indoor air that has been polluted by 15 cigarette smoke and the like, the cost of newly installing a ventilation fan in an indoor space separate from the air conditioner will be high. DISCLOSURE OF THE INVENTION An object of the present invention is to provide an air conditioner or a 20 ventilation device included in the air conditioner that can send outdoor air into an indoor space, and can effectively discharge indoor air to an outdoor space. The ventilation device according to claim 1 is included in an air conditioner and comprises an air path, a fan, and a switching means. The air path connects an indoor space with an outdoor space. The fan has an air intake unit and an air discharge 2 unit. The switching means can switch between a first and a second state. The first state is one in which the air discharge unit of the fan communicates with the air path. The second state is one in which the air intake unit of the fan communicates with the air path. 5 Here, by switching the switching means between the first state and the second state, outdoor air can be sent into an indoor space via the air path and indoor air can be discharged to an outdoor space via the air path. Thus, a switching method can be adopted in which outdoor air is sent into an indoor space when one wants to gently ventilate the indoor space while maintaining a positive pressure therein, and a 10 ventilation method can be adopted in which indoor air is discharged to an outdoor space via the air path when one wants to effectively vent polluted indoor air to the outdoor space. SNote that instead of providing the switching means, the fan can be reciprocally rotated. However, the efficiency with which this type of fan blows air is low, and thus 15 this option is not practical. In consideration of this, the fan employed in the present invention can be one which discharges air in one direction. In addition, the ventilation device according to the present claims may be combined with an air conditioner as original equipment, or may be added to an air conditioner that does not have a ventilation function as an option. 20 The switching device according to claim 2 is the switching device disclosed in claim 1, wherein in addition to switching between the first state and the second state, the switching device also can switch to a third state which closes the air path. The air path of the ventilation device is closed when the switching means is switched to the third state. Thus, if the switching means is switched to the third state 3 in situations such as when a strong wind is blowing outside, undesirable air flows from an outdoor space to an indoor space can be avoided. The ventilation device according to claim 3 is the ventilation device disclosed in claims 1 or 2, in which the fan and the switching means are disposed in an outdoor 5 space. Here, people in an indoor space can avoid feeling uncomfortable because the fan and the switching means are disposed in an outdoor space due to the fact that they may produce noise. The ventilation device according to claim 4 is the ventilation device disclosed 10 in any of claims 1 to 3, in which the ventilation device further comprises a controller. The controller controls the switching means, and thereby switches between air supply from an outdoor space to an indoor space, and air discharge from an indoor space to an outdoor space, by switching the switching means between the first state and the second state. In addition, the controller changes the output of the fan during air supply and air 15 discharge. Here, the controller will consider each characteristic of air supply, in which fresh outdoor air is sent into an indoor space, as well as consider each characteristic of air discharge, in which indoor air is directly discharged to an outdoor space via the air path, e.g., it can increase the output of the fan when discharging indoor air. 20 Conversely, the controller can also reduce the output of the fan when discharging indoor air in situations in which one wants to suppress the amount of sound generated during discharge. The air conditioner according to claim 5 includes the ventilation device disclosed in any of claims 1 to 4, and comprises an indoor unit, an outdoor unit, and a 4 humidification unit. The humidification unit is disposed inside or adjacent to the outdoor unit, and has a fan, a switching means, and a humidifying means. The humidifying means supplies humidified air to the indoor unit via an air path. Here, the fan can be used for ventilation and for supplying humidified air in the 5 humidification unit to an indoor space. Thus, it will be difficult for people indoors to hear the noise from the fan and switching means produced during ventilation and humidification because they are arranged in a humidification unit which is inside or adjacent to the outdoor unit. In addition, by arranging the switching means in the humidification unit, the 10 fan in the humidification unit can be used to vent the indoor air to an outdoor space. The air conditioner comprised of the humidification unit can strengthen the ventilation function at a low >cost. In other words, the fan and the switching means inside the humidification unit of the air conditioner of the present claims can perform ventilation both by supplying outdoor air to an indoor space and by discharging indoor air to an 15 outdoor space. The air conditioner according to claim 6 is the air conditioner disclosed in claim 5, in which the air conditioner further comprises a temperature regulation unit that regulates the temperature of the air in an indoor space. In this air conditioner, by controlling the switching means and switching between a first state and a second state, 20 the switching means will switch between air supply, which supplies outdoor air to an indoor space, and air discharge, which discharges indoor air to an outdoor space. During air discharge, the temperature of indoor air can be more effectively regulated by the temperature regulation unit. During air discharge, it is thought that the temperature of the air indoors will 5 become warmer or cooler than desired because the indoor air heated or cooled by the air conditioner to the desired temperature is discharge to an outdoor space as is via the air path. In consideration of this, the temperature of the indoor air is regulated by the air regulation unit during air discharge, and thus the temperature of the air in an indoor 5 space can be prevented from becoming warmer or cooler than desired. For example, in an air conditioner that carries out inverter control during heating and cooling, abrupt changes in the temperature of the air indoors can be avoided by temporarily increasing the number of compressor cycles during air discharge. The air conditioner according to claim 7 is the air conditioner disclosed in 10 claim 5, in which the indoor unit has a heat exchanger and an indoor fan. The indoor fan is provided in order to take in indoor air into a predetermined space, pass it through the heat exchanger, and discharge it to an indoor space. The air path connects the humidification unit and the predetermined space of the indoor unit. Here, when supplying outdoor air to an indoor space, the outdoor air is sent in 15 from the fan of the humidification unit via the air path, and flows into the predetermined space of the indoor unit. The predetermined space is a space that is upstream of the air flow with respect to the heat exchanger of the indoor unit. Thus, the outdoor air sent into the predetermined space of the indoor unit is drawn into the indoor space via the heat exchanger of the indoor unit. Because of this, there will be less variation in the 20 temperature of the indoor air than compared to when outdoor air is directly supplied to an indoor space. The air conditioner according to claim 8 is the air conditioner disclosed in any of claims 5 to 7, further comprising a pollution sensor that detects the pollution state of the indoor air. 6 Here, the air conditioner can switch between air supply from an outdoor space to an indoor space and air discharge from an indoor space to an outdoor space in response to the pollution state of the indoor air detected by the pollution sensor. For example, the air conditioner can switch to air discharge when the air in an indoor space 5 becomes polluted due to cigarette smoke and the like, and can switch to air supply when the air in an indoor space is not polluted and thus draw in fresh air from outside. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of the exterior structure of an air conditioner 10 according to one embodiment of the present invention. Fig. 2 shows a refrigerant circuit and air flow. Fig. 3 is an exploded perspective view of a conventional outdoor unit. Fig. 4 is a perspective view of a humidification fan of a humidification unit and a switching damper in a first state. 15 Fig. 5 is a cross-sectional view of a humidification fan of a humidification unit and a switching damper near a first state. Fig. 6 is a control block diagram of the air conditioner. Fig. 7 is a perspective view of a humidification fan of a humidification unit and a switching damper in a second state. 20 Fig. 8 is a cross-sectional view of a humidification fan of a humidification unit and a switching damper near a second state. Fig. 9 is a cross-sectional view of a humidification fan of a humidification unit and a switching damper near a third state. 7 BEST MODE FOR CARRYING OUT THE INVENTION <Overall Structure Of The Air Conditioner> Fig. 1 shows the external appearance of an air conditioner that includes a ventilation device according to one embodiment of the present invention. 5 The air conditioner 1 is comprised of an indoor unit 2 that is installed on an indoor wall or the like, and an outdoor unit 3 that is disposed outside. The outdoor unit 3 is comprised of an outdoor air conditioning unit 5 that stores an outdoor heat exchanger, an outdoor fan, and other elements, and a humidification unit 4. An indoor heat exchanger is stored inside the indoor unit 2, and the outdoor heat exchanger is 10 stored inside the outdoor unit 3. Each heat exchanger and refrigerant lines 6 that connect to these heat exchangers form a refrigerant circuit. In addition, an air supply and discharge line 7 is provided in between the humidification unit 4 and the indoor unit 2, and is used when supplying air from the humidification unit 4 to the indoor unit 2, and when discharging indoor air outside via the humidification unit 4. 15 <Structure Of The Refrigerant Circuit> Fig. 2 is a schematic flow diagram of the refrigerant circuit employed in the air conditioner 1, and includes a summary of the flow of air. An indoor heat exchanger 11 is provided in the indoor unit 2. The indoor heat exchanger 11 is comprised of a heat transfer line that has a plurality of curved portions 20 on both ends thereof in the lengthwise direction, and a plurality of fins through which the heat transfer line passes, and exchanges heat with the air that comes in contact therewith. In addition, a cross-flow fan 12 and an indoor fan motor 13 that rotatively drives the cross-flow fan 12 are provided in the indoor unit 2. The cross-flow fan 12 is 8 cylindrical in shape, is provided with blades disposed around the circumferential surface of a rotary shaft, and generates air flow in a direction that is perpendicular to the rotary shaft. The cross-flow fan 12 draws in indoor air into the indoor unit 2, and discharges this air into an indoor space after it has exchanged heat with the indoor heat exchanger 5 11. A compressor 21, a four way directional control valve 22 that is connected to the discharge side of the compressor 21, an accumulator 23 that is connected to the intake side of the compressor 21, an outdoor heat exchanger 24 that is connected to the four way directional control valve 22, and an electric valve 25 that is connected to the 10 outdoor heat exchanger 24, are provided in the outdoor air conditioning unit 5. The electric valve 25 is connected to a line 31 via a filter 26 and a liquid shut off valve 27, and is connected to one end of the indoor heat exchanger 11 via the line 31. In addition, the four way directional control valve 22 is connected to a line 32 via a gas shut off valve 28, and is connected to the other end of the indoor heat exchanger 11 via 15 this line 32. The lines 31, 32 correspond to the refrigerant line 6 shown in Fig. 1. In addition, a propeller fan 29 that discharges air outside after heat exchange with the outdoor heat exchanger 24 is provided in the outdoor air conditioning unit 5. The propeller fan 29 is driven by an outdoor fan motor 30. <Structure Of A Conventional Outdoor Unit> 20 Before describing the structure of the outdoor unit 3, an exploded perspective view (Fig. 3) will be used to describe a conventional outdoor unit that was available prior to the achievement of the present invention. The prior art outdoor unit is comprised of an lower outdoor air conditioning unit and an upper humidification unit, and comprises an outdoor unit casing that 9 includes a base plate 41, a right side plate 42, a left side plate 43, a front plate 44, a protective metal grill 46, a top plate 47, a humidification unit casing 48, and other elements. [Structure Of The Outdoor Air Conditioning Unit] 5 A fan intake port 45 and a divider 49 are installed to the rear of the front plate 44. In addition, an outdoor heat exchanger 24 having an L-shape when viewed from above is installed on a front surface of the protective metal grill 46 that is disposed on a rear surface of the outdoor unit casing. A fan motor mount 50 for attaching the outdoor fan motor 30 is installed on the 10 front surface of the outdoor heat exchanger 24. The outdoor fan motor 30 is provided in order to rotate a propeller fan 29. The propeller fan 29 serves to produce a negative pressure inside a space formed by the fan intake port 45, the divider 49, the left side plate 43, the outdoor heat exchanger 24, and the base plate of the humidification unit casing 48, and brings the air that entered from the rear surface and the left side surface 15 of the outdoor unit casing into contact with the outdoor heat exchanger 24 and discharge it to the front of the front plate 44. Refrigerant circuit components such as a compressor 21, a four way directional control valve 22, an electric valve 25, a liquid shut off valve 27, and a gas shut off valve 28, are disposed in between the dividing plate 49 and the right panel 42, as well as a 20 thermistor 51 that detects the temperature of each of these components. A shut off valve cover 52 is installed on the right side of the right side plate 42, and serves to protect the liquid shut off valve 27 and the gas shut off valve 28. An electric component box 53 is installed above the propeller fan 29, which contains a printed circuit board 54 on which is mounted circuit components for 10 controlling each component of the outdoor unit. A cooling fin 55 is installed on the electrical component box 53, which serves to remove heat produced by the circuit components. [Structure Of The Humidification Unit] 5 The humidification unit is comprised of a humidification unit casing 48 that is disposed on the upper portion of the outdoor unit. The interior of the humidification unit casing 48 includes a space on the right side thereof that accommodates the humidification rotor 58 and other elements, and an absorption fan storage space 75 on the left side thereof that accommodates an absorption fan 81 and other elements. The 10 humidification rotor 58, a heater assembly 64, the humidification fan 70, a cover member 74, the absorption fan 81, and other elements are disposed inside the humidification unit casing 48. The humidification rotor 58 is a ceramic rotor having a honeycomb structure and is generally disk-shaped and has a structure through which air can pass easily. More specifically, as shown in Fig. 3, it is a rotor having a disk shape 15 when viewed from above, and a fine honeycomb structure in horizontal cross section. Air passes through a large number of cylindrical portions in the humidification rotor 58 and are polygon shaped in cross section. The main portion of the humidification rotor 58 is formed from an absorbent such as zeolite and the like and baked in a kiln. Zeolite is used here, but other 20 absorbents such as silica gel or alumina can be employed. Absorbents such as zeolite and the like have the ability to absorb moisture from the air that it comes into contact with, and release that absorbed moisture when it is heated. The humidification rotor 58 is rotatably supported via a rotor guide 60 on a support shaft 59 that is provided on the humidification unit casing 48. Gear teeth are 11 formed on the circumferential surface of the humidification rotor 58, which engage with a rotor drive gear 62 that is installed on a drive shaft on a rotor drive motor 61. The heater assembly 64 is disposed such that it covers approximately half (the 5 right half) of the upper surface of the humidification rotor 58. The heater assembly 64 is comprised of a heater unit 66, an upper cover 65 that covers the heater unit 66, and a lower cover 69. An intake port 67 for taking in air, and a discharge port 68 for discharging air that was heated in the heater unit 66 to the humidification rotor 58, are formed in the lower cover 69. The heater assembly 64 is installed above the 10 humidification rotor 58 via a heater attachment plate 63. A humidification fan 70 is disposed below the humidification rotor 58 in a position facing the heating assembly 64. The humidification fan 70,is a centrifugal fan that is disposed in a space that is connected to a humidification hose 73 (a space below the discharge port 68 of the lower cover 69 of the heater assembly 64). The 15 humidification fan 70 sends out air that passes through the humidification rotor 58 and drops down from the front right side portion of the humidification rotor 58 that is covered (the portion disposed below the discharge port 68 of the lower cover 69 of the heater assembly 64). The humidification hose 73 connects to the air supply and discharge line 7, and supplies air sent from the humidification fan 70 to the indoor unit 20 2. A cover member 74 covers the portion of the upper surface of the humidification rotor 58 that does not have the heater assembly 64 positioned over it (approximately the left half portion thereof). The cover member 74 forms an air flow path that includes a bell mouth 84 (described below) and runs from the upper surface of 12 the left half portion of the humidification rotor 58 to the upper portion of an absorption fan supply space 75 (described below). The absorption fan 81 that is accommodated in the absorption fan storage space 75 is a centrifugal fan that rotates by means of an absorption fan motor 83, supplies air 5 from an opening 85 in the absorbance side bell mouth 84 that is disposed above it, and discharges air toward the exterior of the absorbance fan storage space 75 (the exterior of the humidification unit casing 48). The absorbance side bell mouth 84 is provided in the upper portion of the absorption fan storage space 75, and serves to guide air in the air flow path formed by the cover member 74 to the absorption fan 81. Note that the 10 adsorption fan motor 83 is fixed inside the humidification unit casing 48 by means of a motor mount 82. In addition, a power source substrate 79, an electrical component casing, and the like are disposed inside the humidification unit casing 48. The electrical component casing is comprised of an electrical component box 76 that stores a printed 15 circuit board 78 therein and a lid 77. <Structure Of The Outdoor Unit 3 Of The Present Embodiment> Next, the outdoor unit 3 of the air conditioner according to the present embodiment will be described. The outdoor unit 3 is comprised of an outdoor air conditioning unit 5 in the 20 lower portion thereof and a humidification unit 4 in the upper portion thereof. The outdoor air conditioning unit 5 has the same structure as the conventional outdoor air conditioning unit noted above. On the other hand, the humidification unit 4 includes a switching damper 90 that is not found in the humidification unit of the conventional outdoor unit noted above. 13 [Structure and operation of the switching damper 90] The switching damper 90 is a rotating type air flow path switching means that is disposed below the humidification unit 70, and is comprised of a circular member 92 like that shown in Figs. 4, 5, 7 and 8, and a damper drive motor 91 (see Fig. 6) that 5 rotatively drives the circular member 92. As shown in Fig. 4, the circular member 92 is comprised of a circular base plate 92a, a side wall 92b, a semicircular cone shaped side wall 92c, inner walls 92d, and an inner cylindrical wall 96. Each wall 92b, 92c, 92d, and 96 extends upward from the base plate 92a. The side wall 92b is divided into two by a side opening 92e 10 and the semi-conical side wall 92c. The inner walls 92d are comprised of three plates that radiate outward from near the center of the circular member 92. The circular member 92 is divided into a first space 93, a second space 94, and a third space 95 by means of the inner walls 92d (see Fig. 4). The first space 93 does not have the side wall 92b, and is a space that is open sideways by means of the side opening 92e. Two 15 circular holes 94a, 94b are formed in the base plate 92a of the second space 94. The inner cylindrical wall 96 disposed in the second space 94 extends upward from the periphery of the circular hole 94b. The semi-conical side wall 92c is provided adjacent to the circular hole 94a, and this surface has a shape that approximates an upside down cone that has been divided into half vertically. As shown in Fig. 7 and 8, the space that 20 is enclosed by the outer surface of the semi-conical side wall 92c is a space that is open to the sides. In addition, each space 93, 94, 95, the space surrounded by the outer surface of the semi-conical side wall 92c, and the space surrounded by the inner surface of the inner cylindrical 96 open upward. On the other hand, as shown in Figs. 5 and 8, the humidification fan 70 that is 14 disposed on top of the circular member 92 includes a blade shaft 70a, an air intake port 70b, and an air discharge port 70c. The air intake port 70b and the air discharge port 70c are formed on the bottom surface of the casing of the humidification fan 70, and face toward the upper opening of the circular member 92. 5 The damper drive motor 91 is provided in order to rotate the circular member 92 in the manner shown in Figs. 5 and 8. Although not shown in Figs. 5 and 8, the damper drive motor 91, for example, is disposed below the circular member 92. The damper drive motor 91 rotates the circular member 92, and switches between a first state in which the circular member 92 comes to the rotation position shown in Figs. 4 10 and 5, and a second state in which the circular member 92 comes to the rotation position shown in Figs. 7 and 8. In the first state, a path 89 (see Fig. 5) that guides.humidified air that passed through the heater assembly 64 and the humidification rotor 58, or outside air, to the circular member 92 of the switching damper 90 communicates with the first space 93 of 15 the circular member 92 via the side opening 92e. In addition, in the first state, the first space 93 of the circular member 92 communicates with the air intake port 70b of the humidification fan 70 via the upper opening. Furthermore, in the first state, the upper part of inner cylindrical wall 96 of the cylindrical member 92 communicates with the air discharge port 70c of the humidification fan 70, and communicates with a hose 20 connector 3a that the humidification hose 73 is connected to on the lower part thereof, and thus the air discharge port 70c of the humidification fan 70 is linked with the humidification hose 73. In the first state, the air that was discharged from the air discharge port 70c of the humidification fan 70 passes through the air supply and discharge line 7 and is supplied to the indoor unit 2 because the humidification hose 73 15 is connected to the air supply and discharge line 7. Thus, in the first state, air flows in the direction illustrated by the dotted and dashed line of Figs. 4 and 5, and humidified air or outdoor air passes through the air supply and discharge line 7 and is supplied to the indoor unit 2. 5 On the other hand, in the second state, the connector 3a that the humidification hose 73 is connected to communicates with the second space 94 of the circular member 92 via the circular hole 94a. In addition, the second space 94 communicates with the air intake port 70b of the humidification fan 70 via the upper opening. Furthermore, in the second state, the air discharge port 70c of the humidification fan 70 is positioned 10 above the semi-conical side wall 92c of the circular member 92, and the air discharge port 70c is connected to the path 3b that passes through the outside of the device (the outside of the outdoor unit 3) via the space that is surrounded by the semi-conical side wall 92c. Thus, in the second state, air flows in the direction illustrated by the dotted and dashed line of Figs. 7 and 8, and air that was discharged from the indoor unit 2 and 15 passed through the air supply and discharge line 7 is discharged from the air discharge port 70c of the humidification fan 70 to the outside of the unit. Note that as shown in Fig. 2, the air supply and discharge line 7 is connected to the predetermined space 2a of the indoor unit 2. The predetermined space 2a is a space upstream from the air flow of the indoor heat exchanger 11, and is a space in 20 which pre-heat exchanged air resides. Thus, the air that passed through the air supply and discharge line 7 and supplied to the indoor unit 2 is carried on the air flow inside the indoor unit that is produced by the cross-flow fan 12, and is discharged to an indoor space after heat exchange with the indoor heat exchanger 11. [Operation Of The Humidification Unit 4] 16 The switching damper 90 is switched to the first state shown in Figs. 4 and 5 when humidification is to occur. The humidification unit 4 takes in air from the outside into the humidification unit casing 48 by rotatively driving the absorption fan 81. The air that entered into the 5 humidification unit 48 passes through the left half portion of the humidification unit 58, and is discharged from the absorption fan storage space 75 to the exterior thereof via the air flow path formed by the cover member 74 and the absorption side bell mouth 84 and the absorption fan 81. When the air taken into the humidification rotor 48 from the outside passes through the left half portion of the humidification rotor 58, the 10 humidification rotor 58 adsorbs moisture contained in the air. The left half portion of the humidification rotor 58 that absorbed moisture in this absorption step will become the right half portion of the humidification rotor 58 by rotating the humidification rotor 58. In other words, the absorbed moisture moves to a portion of the humidification rotor 58 that is disposed below the heater assembly 64 in 15 accordance with the rotation of the humidification rotor 58. Then, the moisture that moved to this position is released to the air flow produced by the humidification fan 70 due to heat from the heater unit 66 of the heater assembly 64. When the humidification fan 70 rotates, air is taken into the humidification unit casing 48 from the exterior thereof. This air flows from the bottom of the inside of the 20 left half portion of the humidification rotor 58 upward, and is guided into the upper cover 65 from the intake port 67 of the upper cover 69. Then, the air that entered into the upper cover 65 flows from the upper part of the left half portion of the humidification rotor 58 downward to the humidification fan 70 via a through path 89 and the switching damper 90. This air flow is produced by the humidification fan 70. 17 The humidification fan 70 blows the air that passed through the humidification rotor 58 and the switching damper 90 to the indoor unit 2 via the humidification hose 73 and the air supply and discharge line 7. The air blown to the indoor unit 2 includes the moisture absorbed by the humidification rotor 58. 5 Thus, the air supplied to the indoor unit 2 from the humidification unit 4 is discharged to an indoor space from the predetermined space 2a via the indoor heat exchanger 11. <Structure And Control Of The Controller 100> The controller 100 is divided between the electrical component boxes disposed 10 in the indoor unit 2, the outdoor air conditioning unit 5, and the humidification unit 4 of the air conditioner 1. .The controller 100 is connected to the equipment in the indoor unit 2 and the outdoor unit 3 as shown in Fig. 5, and controls the operation of each piece of equipment in response to each operational mode such as heating, cooling, drying, humidification, air supply, and air ventilation. 15 [Control Of The Humidification Operation] The controller 100 will conduct a humidification operation if it receives a humidification command or an automatic humidification command from a remote control 102. The humidification operation may be carried out together with a heating operation. The humidification operation drives the rotor drive motor 61 inside the 20 humidification unit 4, the heater unit 66, the motor that rotates the humidification fan 70, and the absorption fan motor 83. In the humidification operation, as noted above, moisture in the air introduced into the humidification unit 4 from the exterior thereof due to the rotation of the absorption fan 81 is absorbed by the humidification rotor 58. Air heated by the heater unit 66 flows through the humidification rotor 58 due to the 18 rotation of the humidification fan 70, and air which includes the moisture released from the humidification rotor 58 is supplied to the indoor unit 2 via the air supply and discharge line 7. [Ventilation By Means Of The Air Supply Operation Or The Air Discharge Operation] 5 In addition, the controller 100 will conduct an air supply operation or an air discharge operation if it determines that an indoor space needs to be ventilated. The air supply operation draws in outdoor air into the humidification unit 4, and supplies this outdoor air from the air supply and discharge line 7 to the indoor unit 2. The air discharge operation draws in the air inside the air supply and discharge line 7 by means 10 of the humidification fan 70 of the humidification unit 4, i.e., it draws indoor air into the air supply and discharge line 7 via the indoor unit 2, and then discharges this air from the humidification fan 70 to the exterior or the outdoor unit 3. The flow of air during the air supply operation and the air discharge operation is as described above (Structure and operation of the switching damper 90) for the first state and the second state. 15 During the air supply operation, the switching damper 90 is placed in the first position, the air flows in the direction illustrated by the dotted and dashed lines of Figs. 4 and 5, and outdoor air passes through the air supply and discharge line 7 and is supplied to the indoor unit 2. On the other hand, during the air discharge operation, the switching damper 90 is placed into the second state, the air flows in the direction illustrated by the 20 dotted and dashed lines of Figs. 7 and 8, and the air that was discharged from the indoor unit 2 and passed through the air supply and discharge line 7 is discharged form the air discharge port 70c of the humidification unit 70 to the exterior thereof. Note that in the air supply operation and the air discharge operation, the absorption fan 81 of the humidification unit 4 and the rotor drive motor 61 are not operated and only the 19 humidification fan 70 is rotated. The controller 100 determines, based upon the operational mode set by the remote control 102 and the detection results of the pollution sensor 101, whether or not it is necessary to ventilate an indoor space, and the selection between the air supply 5 operation and the air discharge operation. The pollution sensor 101 is provided in the indoor unit 2, and detects the pollution state of indoor air. The controller 100 determines that an indoor space needs to be ventilated if the operational mode is automatic operation, and if the pollution state exceeds a first tolerance level. Then, the controller 100 selects the air supply operation when the 10 pollution state exceeds the first tolerance level and is less than a second tolerance level, and selects the air discharge operation when the pollution state exceeds the second tolerance level. In addition, a user of the air conditioner 1 can directly select the air supply operation or the air discharge operation as the operational mode from the remote control 102. For example, if an indoor space is smoky due to cigarette smoke and one 15 wants to use the air conditioner 1 instead of the a ventilation fan, it is preferred that the user directly select the air discharge operation. In addition, if one wants to draw in fresh outdoor air while heating or cooling and wants to gently ventilate an indoor space, the user can select the air supply operation. Note that the humidification fan 70 is controlled so that the output is larger 20 during the air discharge operation than during the air supply operation. In addition, during the air discharge operation, the controller 100 increases the number of cycles in the inverter control of the compressor 21, and thus the number of rotations of the motor of the compressor 21 will increase. <Characteristics Of The Air Conditioner 1> 20 (1) In the air conditioner 1, both an air supply operation that sends in outdoor air into an indoor space via the air supply and discharge line 7 (air path), and an air discharge operation that discharges indoor air to the outside via the air supply and 5 discharge line 7, can be carried out by switching between a first state and a second state of the switching damper 90 inside the humidification unit 4. Thus, either the air supply operation or the air discharge operation can be selected when who desires to ventilate an indoor space. (2) 10 In the air conditioner 1, the humidification fan 70 and the switching damper 90 that operate in the humidification operation, the air supply operation, and the air discharge operation, are disposed inside the outdoor humidification unit 4. Because of that, noise produced by these devices will be almost entirely prevented from making people indoors from feeling uncomfortable. 15 (3) In the air conditioner 1, the output of the humidification fan 70 during the air discharge operation is controlled such that it is larger than the output thereof during the air supply operation, and thus the ventilation effect of the air discharge operation when selected in order to quickly ventilate an indoor space will be greatly increased. On the 20 other had, the humidification fan 70 is operated with a comparatively small output in the air supply operation that is employed in a ventilation method in which fresh outdoor air is sent into an indoor space. (4) In the air conditioner 1, the humidification fan 70 is used for the air supply 21 operation and the humidification operation, just like it is in the prior art. In addition, the humidification fan 70 can be used in the air discharge operation to discharge indoor air to the outside by providing a switching damper 90 in the humidification unit 4. In an air conditioner comprised of a humidification unit, an 5 engineering change can be made that strengthens the ventilation function at a low cost in this way. (5) When discharging air with the air conditioner 1, it is thought that the temperature of the air indoors will become warmer or cooler than desired because the 10 indoor air heated or cooled by the air conditioner to the desired temperature is discharged outside as is via the air supply and discharge line 7. In consideration of this, the number of cycles in the inverter control of the compressor 21 is increased during the air discharge operation. Thus, even if air is discharged from the indoor space, the worsening of the temperature therein will be kept to a minimum, and thus sudden 15 changes in the temperature in the indoor space can be avoided. (6) In the air conditioner 1, outdoor air that is sent from the humidification fan 70 of the humidification unit 4 via the air supply and discharge line 7 flows into the predetermined space 2a of the indoor unit 2 during the air supply operation that supplies 20 outdoor air to an indoor space. Outdoor air that flowed into the predetermined space 2a is discharged to an indoor space via the indoor heat exchanger 11 because the predetermined space 2a is positioned upstream with respect to the indoor heat exchanger 11. Thus, there will be less variation in the temperature of the indoor air than compared to when outdoor air is directly supplied to the indoor space. 22 [Other Embodiments] (A) The switching damper 90 can not only be placed in the first and second states, but it can also be placed in a third state shown in Fig. 9 that is also effective. In this 5 third state, a portion of the base plate 92a of the circular member 92 covers the upper opening of the hose connector 3a that the humidification hose 73 is connected to. Thus, the state in which the outside and the indoor space are linked via the air supply and discharge line 7 and the humidification hose 73 will be eliminated by means of the base plate 92a of the circular member 92, and the air supply and discharge line 7 will not be 10 linked to the outside or the indoor space. If the switching damper 90 is switched to the third state by manual or automatically controlling the same, undesirable air flows from the outside to an indoor space can be suppressed in situations in which a strong wind is blowing outside, or in Other situations as needed. 15 (B) The pollution sensor 101 is provided in the indoor unit 2 in the aforementioned embodiment, but it is thought that the pollution sensor 101 can be omitted in situations in which a user determines the necessity of ventilation and/or the selection of the air supply operation and the air discharge operation. 20 (C) A rotating type of switching damper 90 is used in the aforementioned embodiment, however a peripheral structure can be devices so that a slide type switching damper can be used. (D) 23 The humidification fan 70 is controlled so that the output thereof during the air discharge operation is greater than during the air supply operation in the aforementioned embodiment, however it is thought the humidification fan 70 can be controlled so that the output thereof during the air discharge operation is less than during the air supply 5 operation. INDUSTRIAL APPLICABILITY If the switching device and the air conditioner according to the present invention are used, outdoor air can be sent into an indoor space via the air path and 10 indoor air can be vented outside via the air path by switching the switching means between the first state and the second state. Thus, a switching method can be adopted in which outdoor air is sent into an indoor space when one wants to gently ventilate the indoor space while maintaining a positive pressure therein, and a ventilation method can be adopted in which indoor air is vented outside via the air path when one wants to 15 effectively vent polluted indoor air to the outdoors. 24