JP2001330298A - Control method of air-conditioning system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control method of an air-conditioning system producing an airflow direction changing characteristic, more comfortable and more healthy for an inhabitant, by air streams more approximated to natural wind for the inhabitant. SOLUTION: The air-conditioning system constituted of a plurality of fans is controlled so as to produce airflows having the change of airflow directions. wherein the air stream generating times and the rate of them of respective airflow directions of the horizontal component of airflows received by the inhabitant, the changing range of airflow directions, angles between the airflow directions and the like, are within respective optimum ranges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system for generating a plurality of airflows having different horizontal component wind directions by controlling the airflow of a plurality of blowers.

[0002]

2. Description of the Related Art Conventionally, in this type of air-conditioning system control method, as shown in, for example, Japanese Patent Application Laid-Open No. 4-43243, the air flow sending timing from a plurality of air outlets arranged so as to be radially concentric is known. By controlling the time series, the power spectrum of the time change of the wind direction angle in the living space exhibits a so-called 1 / f characteristic that is inversely proportional to the frequency, so that an airflow having a natural wind direction change is obtained.

[0003]

However, in the above-described conventional configuration, if the time change of the wind direction angle is only the 1 / f characteristic, it only partially expresses the natural wind phenomenon, and the occupants cannot enjoy the natural wind phenomenon. On the other hand, there was a problem that natural windiness could not be sufficiently given. Also, there is a problem that sufficient comfort cannot always be provided depending on the occupant's condition or environmental condition if the change in wind direction is only the 1 / f characteristic. The present invention is to solve such a conventional problem, in an air conditioning system that generates a plurality of airflows with different horizontal component wind directions by controlling the airflow of a plurality of blowers, more natural for a resident,
It is another object of the present invention to provide a method for controlling an air conditioning system that generates an airflow having a wind direction change characteristic that provides a more comfortable and healthy airflow for a resident.

[0004]

In order to solve the above-mentioned problems, in the control method of an air conditioning system constituted by a plurality of blowers, the present invention according to the first aspect of the present invention provides a method for controlling a horizontal wind direction component of a wind received by a resident. The present invention is characterized in that a reference wind direction is provided, and an airflow closer to the reference wind direction increases a time ratio of airflow generation.

According to a second aspect of the present invention, in the control method of the air conditioning system according to the first aspect, a time ratio of airflow generation is determined according to a wind speed.

According to a third aspect of the present invention, in the control method of the air conditioning system according to the first aspect, means for selecting a reference wind direction by a resident is provided.

According to a fourth aspect of the present invention, there is provided an air conditioning system including a plurality of blowers, wherein one of the air blowers has the same wind direction.
It is characterized in that an upper limit value of the airflow generation time is set.

According to a fifth aspect of the present invention, in the control method of the air conditioning system according to the fourth aspect, the upper limit is determined according to a wind speed.

According to a sixth aspect of the present invention, there is provided an air-conditioning system including a plurality of blowers, wherein the horizontal direction component of the wind received by the occupant is greater than a predetermined angle.

According to a seventh aspect of the present invention, in the air conditioning system according to the sixth aspect, the angle of any two generated horizontal wind direction components is equal to or larger than a predetermined angle.

According to an eighth aspect of the present invention, in the air conditioning system and the control method therefor according to any one of the first to seventh aspects, a part of the air flow is lower than a room temperature by a predetermined temperature or more. I do.

According to a ninth aspect of the present invention, in the air conditioning system and the control method thereof according to the eighth aspect, an upper limit is set for one airflow generation time of an airflow lower than room temperature by a predetermined temperature or more.

According to a tenth aspect of the present invention, in the air conditioning system and the control method therefor according to the eighth or ninth aspect, the generation time interval from the stop of the airflow lower than the room temperature by a predetermined temperature or more to the re-generation is set to a predetermined time. It is characterized by the above.

The present invention according to claim 11 is the invention according to claims 8 to 1.
0. The air conditioning system and the control method thereof according to any one of claims 1 to 3, further comprising a room temperature setting unit configured to set a room temperature in the air conditioning system, and determining an airflow generation ratio lower than the room temperature by a predetermined temperature or more according to a difference between the room temperature and the set temperature. It is characterized by doing.

The present invention according to claim 12 is the invention according to claims 8 to 1.
The air-conditioning system and the control method thereof according to any one of the preceding claims, wherein an airflow other than an airflow lower than a room temperature by a predetermined temperature or more and an airflow other than an airflow lower than the room temperature by a predetermined temperature or more are not simultaneously generated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an air conditioning system constituted by a plurality of blowers, a first embodiment of the present invention is as follows.
A control method for an air conditioning system, wherein a reference wind direction is provided in a horizontal wind direction component of a wind received by a resident, and an airflow closer to the reference wind direction is characterized by increasing a time ratio of airflow generation. This has the effect that a wind direction distribution characteristic close to a natural wind can be obtained.

The second embodiment of the present invention is the control method of the air conditioning system according to claim 1, wherein the time ratio of the generation of the air flow is determined according to the wind speed. Therefore, it is possible to obtain a wind direction distribution characteristic closer to a natural wind.

A third embodiment of the present invention is the control method for an air conditioning system according to claim 1, further comprising means for selecting a reference wind direction by the occupant. The main wind direction of the airflow can be adjusted to suit the user's preference, and the resident can feel the wind direction characteristics closer to the natural wind regardless of the direction in which the resident stays.

A fourth embodiment of the present invention is a method for controlling an air conditioning system, wherein an upper limit value of one airflow generation time of the same wind direction is provided, whereby the wind direction does not change for a long time. This has the effect of making it possible to feel a more natural change in the wind direction without feeling unnaturalness due to this.

A fifth embodiment of the present invention is the control method for an air conditioning system according to claim 4, wherein said upper limit value is determined according to a wind speed. This has the effect of preventing annoyance and discomfort caused by exposure to the same place for a long time.

A sixth embodiment of the present invention is a control method of an air conditioning system characterized by generating a wind in which a horizontal wind direction component of a wind received by a occupant is equal to or greater than a predetermined angle. It has the effect of giving a more natural sense of airflow to a person and a higher level of comfort.

The seventh embodiment of the present invention is characterized in that the angle of any two generated horizontal wind direction components is equal to or larger than a predetermined angle. This is a control method, which has an effect that a higher feeling of comfort can be given when a wind direction change occurs.

The air-conditioning system according to any one of claims 1 to 7, wherein a part of the airflow is lower than a room temperature by a predetermined temperature or more. Method, whereby the moderate cool feeling received from some wind directions prevents the sense of use for the wind direction change,
This has the effect that the feeling of comfort due to the change in wind direction can always be maintained.

The ninth embodiment of the present invention is the air conditioning system and the control method therefor according to claim 8, wherein an upper limit is set for one airflow generation time of an airflow lower than room temperature by a predetermined temperature or more. This has the effect of preventing the body from getting cold and uncomfortable due to the cold airflow hitting the same place on the body for a long time, and maintaining the comfortable feeling due to the change in wind direction.

The tenth embodiment of the present invention is characterized in that the generation time interval from the stop of the airflow lower than the room temperature by a predetermined temperature or more to the re-generation is set to a predetermined time or more. An air conditioning system and a control method therefor according to the present invention, whereby it is possible to prevent cooling and discomfort of the body due to frequent hitting of the same place of the body with a cold airflow, and to always maintain a comfortable feeling due to a change in wind direction. Having.

In an eleventh embodiment of the present invention, the air conditioning system is provided with room temperature setting means for setting a room temperature, and an air flow generation ratio lower than the room temperature by a predetermined temperature or more is determined according to a difference between the room temperature and the set temperature. The air conditioning system and the control method thereof according to claim 8, wherein
This has the effect of allowing the user to feel the comfort due to the change in the wind direction without impairing the sense of coolness.

The twelfth embodiment of the present invention is characterized in that an air current lower than room temperature by a predetermined temperature or more and an air flow other than an air flow lower than the room temperature by a predetermined temperature or more are not simultaneously generated. The air-conditioning system and the control method thereof according to the above item, which have an effect that it is possible to prevent a mixture of airflows having different temperatures from lowering a sense of coolness caused by a low-temperature airflow.

[0028]

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

According to the control method of the air conditioning system of the present embodiment, as shown in FIG. 1, a plurality of air flows such as an air conditioner 2, a circulator 3, a blower additional humidifier 4, and an air cleaner 5 with a blower are provided in a room 1. A control device is arranged, and an airflow environment having a wind direction change is generated in the space 6 in which a person lives by the airflow sent from the outlet of each airflow control device. Each airflow control device has a different horizontal component wind direction 8 (8a, 8b, 8c, 8d) with respect to the main shaft 7 (7a, 7b, 7c, 7d) of the airflow sent from each outlet toward the occupant. It is possible to generate a wind direction change in which the wind direction of the horizontal component with respect to the occupant changes in a range of 360 degrees in the front, rear, left and right directions. The controller 9 is capable of controlling each of the airflow control devices via a wireless signal, and controls the air volume of the blown airflow of each of the airflow control devices in a time-series manner.
The wind direction and speed of the airflow for the resident can be arbitrarily changed over time.

The operation of the control method for the air conditioning system configured as described above will be described with reference to FIGS.

FIG. 2 is a plan view showing the arrangement of airflow control devices and occupants in the room 1 of FIG. So that the wind direction of the horizontal component for the resident is different by 90 degrees,
A circulator 3 in front of the occupant, an air conditioner 2 in the rear, an additional humidifier 4 on the left, and an air cleaner 5 with a blower on the right, the wind direction of the horizontal component changes 360 degrees forward, backward, left and right. Create a flowing air environment. The airflow control method for each of the front, rear, left, and right wind directions applies the following wind direction characteristics of natural wind.

FIG. 3 is an explanatory diagram showing the wind direction distribution characteristics of natural winds, and shows the time ratio of airflow generation for each horizontal component wind direction in natural winds measured in a birch forest on a plateau. The angle range is divided into four by 90 degrees, and the time ratio of airflow generation in each range is indicated by%). As shown in FIG. 3A, in the wind in the natural world, an airflow having a horizontal component wind direction is generated in all directions in the front, rear, left, and right directions. It is considered that a feeling of airflow close to the wind is obtained. Therefore, the airflow environment having the wind direction change of the front, rear, left, and right horizontal components obtained in the present embodiment can give a resident a sense of airflow that is almost the most natural wind.

FIG. 4 shows the occupants declaring and evaluating the degree of comfort under a plurality of airflow environments in which the angle range of the wind direction change of the horizontal component is different, and the resulting wind direction change angle range and comfort level of the horizontal component are obtained. Shows the relationship. As the horizontal component wind direction change angle range becomes larger, the degree of comfort also increases. Within a predetermined angle (within about 180 degrees in the figure), the increase in comfort is remarkably observed, and above the predetermined angle, the comfort gradually increases. 3
At 60 degrees, the degree of comfort tends to be the highest. Therefore, when the airflow control devices cannot be installed in front, rear, left and right due to the structure of the room or the like, if the airflow control devices are arranged so that a wind direction change range of a horizontal component of at least 180 degrees can be obtained, a sufficiently high level of comfort can be achieved. Can be given.

FIG. 5 shows the relationship between the wind direction change angle of the horizontal component when the wind direction change occurs and the comfort reporting rate at that time, obtained from the subject's experiment. When the wind direction change angle of the horizontal component is equal to or greater than a predetermined angle (approximately 60 degrees or more in the figure), the comfort reporting rate tends to be the highest. Therefore, by arranging the airflow control devices so that the difference in the horizontal component wind direction angle between the adjacent airflow control devices becomes at least 60 degrees or more, it is possible to provide a higher sense of comfort when a wind direction change occurs.

Further, FIG. 3A shows the following characteristics as wind direction distribution characteristics of natural wind. Assuming that the wind direction of the horizontal component (reference wind direction) having the largest airflow time ratio is the reference angle 0 °, the closer the wind direction angle of the horizontal component is to the reference wind direction, the greater the airflow generation time ratio is, and conversely, the horizontal direction from the reference wind direction. The longer the component wind direction angle is, the smaller the time ratio of airflow generation is. In FIG. 3B, the wind direction distribution characteristics are shown for each wind speed range (0.2 m / s or more and less than 0.2 m / s). As a result, the characteristic is such that the difference in the time ratio of airflow generation between the wind directions becomes smaller as the airflow becomes lower.

FIG. 6 shows the time series of the airflow control devices based on the measured data of the wind direction and the wind speed of the natural wind in order to reproduce the time ratio of the airflow generation for each wind direction in the natural wind as shown in FIG. This is the creation of the air volume setting value. These air volume setting values are transmitted as control signals from the controller 9 to the respective airflow control devices. FIG. 7A shows the time ratio of the airflow generated by the wind direction in the actually generated residential area, and FIG. 7B shows the time ratio of the airflow generated by the wind direction for each wind speed region. In this manner, substantially the same wind direction distribution characteristics as those of the natural wind shown in FIGS. 3A and 3B can be obtained. FIG. 8 shows a temporal change of the wind direction in the natural wind and the wind generated by the present control method,
FIG. 9 shows a temporal change of the wind speed in the natural wind and the wind generated by the present control method.

As described above, according to the present control method, it is possible to realize an airflow environment closer to the natural wind in the living area, and to feel a more natural airflow feeling in the living area.

FIG. 10 shows an operation section of the controller 9, and reference wind direction setting switches 10a to 10a for the resident to directly select the reference wind direction in which the time ratio of the airflow generation is the largest.
d, and an airflow generation time adjustment switch 11a to which the occupant can increase or decrease the time ratio of the airflow generation for each wind direction as desired.
11d is provided.

For example, in the arrangement of the resident and the respective airflow control devices as shown in FIG. 2, when the resident who likes the airflow from the front sets the airflow from the circulator 3 in the front direction to the reference wind direction, When the person's sitting direction changes to the right by 90 degrees, the reference wind direction can be easily changed by the following operation. By pressing the reference wind direction setting switch 10d corresponding to the air cleaner with blower 5 in front of the resident,
The time-series air volume setting value of the air purifier 5 with the blower is set to switch 1
It is possible to replace the time-series airflow setting value of the circulator 3 with the largest airflow generation time ratio set before pressing 0d. Similarly, the air conditioner 2 is set to the time-series air flow set value of the air cleaner 5 with a blower, the blower additional humidifier 4 is set to the time-series air flow set value of the air conditioner 2, and the circulator 3 is set to the time-series air flow set value of the blower additional humidifier 4. 11, the wind direction distribution characteristics are obtained by rotating the original wind direction distribution characteristics (FIG. 7) to the right by 90 degrees as shown in FIG. 11, and maintain the wind direction distribution characteristics according to the change in the direction of the resident. The reference wind direction can be easily changed while doing so.

For example, in the arrangement of the resident and the respective airflow control devices as shown in FIG. 2, if the resident wants to feel more airflow from behind, the airflow generation time adjustment switch 11a corresponding to the air conditioner 2 may be used. By pressing the + side once, the time ratio of airflow generation of the air conditioner 2 can be increased by a predetermined ratio. In addition, the time ratio of the airflow generation of each of the other airflow control devices decreases correspondingly. Therefore, it is possible to change and adjust the wind direction distribution characteristics that are more comfortable for the occupants. FIG. 12 shows the wind direction distribution after adjusting the time ratio of airflow generation.

FIG. 13 is a graph showing the relationship between the time during which the air current having the same wind direction and the wind speed of 0.5 m / s is maintained, and the comfort of the occupant. As described above, when the time during which the airflow having the same wind direction is maintained exceeds T1, there is a characteristic that the comfort is reduced to the uncomfortable side. Therefore, an upper limit is set for the time for continuously generating airflow from the same airflow control device, and by switching the airflow generation to an airflow control device having a different wind direction within this time limit, the airflow of the same wind direction is maintained. Discomfort can be prevented.

FIG. 14 is an explanatory diagram showing the relationship between the time during which the airflow continues in the same wind direction and the comfort of the occupant, depending on the wind speed of the generated airflow. From the figure, when the same wind direction duration that can maintain a comfortable feeling on the comfortable side is obtained for each different wind speed range, T2 when the wind speed is 0.2 m / s, T3 when the wind speed is 0.5 m / s,
At the time of 0.8 m / s or more, it becomes T4, and there is a characteristic (T2>T3> T4) in which the higher the wind speed, the shorter the same wind direction duration in which the comfortable feeling can be maintained on the comfortable side. Therefore, by setting the upper limit value of the time for continuously generating an airflow to be shorter as the amount of air blown out from the same airflow control device is larger, and switching the airflow generation to an airflow control device having a different wind direction within this time limit, Regardless of the wind speed level, it is possible to always prevent discomfort due to the same wind direction.

The air-conditioning system according to the present embodiment has the configuration shown in FIG.
The air conditioner 2 is provided as an airflow control device capable of controlling the temperature of the blown airflow as shown in FIG. 1 and an airflow lower than a room temperature by a predetermined temperature can be generated at an arbitrary timing from a predetermined wind direction. The air conditioner 2 always needs to blow cool air to control the room temperature during the cooling operation, and the airflow to the occupant is controlled by whether or not the airflow is directed to the occupant by the wind direction vane. Thereby, during the cooling operation, an effect is obtained in which a moderate sense of coolness received from a part of the wind direction can prevent the user from getting used to the sense of the change in the wind direction, and can always maintain a comfortable feeling due to the change in the wind direction.

FIG. 15 is a graph showing the relationship between the duration of cold air at a predetermined temperature lower than room temperature and the occupant's feeling of comfort.
For example, the airflow temperature is 3 ° C. lower than room temperature and the wind speed is 0.5 m / s.
In the case of the cold air, it is necessary to keep the cool air duration within T5 in order to prevent discomfort. In the case of cold air having an airflow temperature 6 ° C. lower than room temperature, discomfort is exhibited regardless of the cool air duration. Therefore, while generating a cool air whose airflow temperature is appropriately lower than room temperature, and keeping the duration within a predetermined time, while preventing cold and discomfort caused by the cold airflow hitting the same place on the body for a long time, It is possible to always maintain a comfortable feeling due to the change in the wind direction.

FIG. 16 is a graph showing the relationship between the time interval from when cold air having a predetermined temperature lower than room temperature is stopped until it is regenerated and the comfort of the occupant. For example, in the case of cold air having an airflow temperature of 3 ° C. lower than room temperature and a wind speed of 0.5 m / s, the time interval between the end of the generation of the cold air and the restart thereof is T6 or more in order to prevent discomfort. Need to be Thereby, it is possible to always maintain the comfortable feeling due to the change in the wind direction while preventing the cold and the discomfort caused by the frequent cold airflow hitting the same place on the body.

FIG. 17 shows the air flow generation time ratio of each air flow control device set according to the difference between the room temperature and the set temperature in the control method of the air conditioning system of this embodiment. Since the occupants feel hotter and more uncomfortable as the room temperature becomes higher than the set temperature, it is necessary to apply more airflow to the occupants whose airflow temperature is lower than the room temperature by a predetermined temperature or more. Therefore, in the control method of the air-conditioning system according to the present embodiment, as shown in FIG. By reducing the time ratio of the airflow generation by the airflow control device, it is possible to obtain the effect that the occupants can feel the comfort due to the change in the wind direction while eliminating the discomfort caused by the heat and maintaining the coolness. At this time, by controlling so that the airflow lower than the room temperature by a predetermined temperature or more and the airflow within the predetermined temperature from the room temperature are not generated at the same time, the airflows of different temperatures are mixed and the sense of coolness by the airflow lower than the room temperature by the predetermined temperature is reduced. Can be prevented. In addition, when the room temperature is much higher than the set temperature, when returning home from a very hot outdoors, or after taking a bath, etc., the air-conditioner 2 sets the generation time ratio of the cool air to 100%, and the airflow generation of other airflow control devices. It is also possible to obtain a faster and more comfortable cooling environment by directing the cool air to the resident at all times by stopping the air conditioner.

[0047]

As is clear from the above embodiment, according to the present invention, in an air conditioning system in which a plurality of blowers generate a plurality of airflows having different horizontal component wind directions, the level of each occupant can be controlled by controlling the amount of air of each blower. Generates a wind direction change in which the wind direction change range of the components and the angle difference between the wind directions are each equal to or greater than a predetermined angle, and controls the wind speed and air temperature of each wind direction and the time of air flow generation for each wind direction according to the occupant's request By doing, with the air flow closer to the natural wind,
In addition, it is possible to provide a control method of an air conditioning system that generates a wind direction change characteristic that is more comfortable and healthy for a resident.

[Brief description of the drawings]

FIG. 1 is a three-dimensional configuration diagram of a method for controlling an air conditioning system according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement state of the same embodiment.

FIG. 3 is an explanatory diagram showing a wind direction distribution of a natural wind.

FIG. 4 is an explanatory diagram showing a relationship between an angle range of a wind direction change and a feeling of comfort;

FIG. 5 is an explanatory diagram showing a relationship between a wind direction change angle and a comfortable report rate when a wind direction change occurs.

FIG. 6 is an explanatory diagram showing control values of the same embodiment.

FIG. 7 is an explanatory diagram showing a wind direction distribution by a control operation of the same embodiment.

FIG. 8 is an explanatory diagram showing a wind direction change by a control operation of the same embodiment.

FIG. 9 is an explanatory diagram showing a change in wind speed due to a control operation of the same embodiment.

FIG. 10 is an explanatory diagram illustrating an operation unit of the controller according to the same embodiment.

FIG. 11 is an explanatory diagram showing a wind direction distribution by a control operation of the same embodiment.

FIG. 12 is an explanatory diagram showing a wind direction distribution by a control operation of the same embodiment.

FIG. 13 is an explanatory diagram showing a relationship between a wind direction duration and a feeling of comfort in the same embodiment.

FIG. 14 is an explanatory diagram showing a relationship between a wind direction duration and a feeling of comfort in the same embodiment.

FIG. 15 is an explanatory diagram showing a relationship between a cool air duration and a feeling of comfort in the same embodiment.

FIG. 16 is an explanatory diagram showing a relationship between a time interval until cold air reappears and a feeling of comfort in the same embodiment.

FIG. 17 is an explanatory diagram showing the airflow generation time for each wind direction by the control operation of the same embodiment.

[Explanation of symbols]

 Reference Signs List 1 room 2 air conditioner 3 circulator 4 blower additional humidifier 5 air cleaner with blower 6 living space 7 main axis of wind direction of each airflow control device 8 wind direction of horizontal component of each airflow control device 9 controller 10 airflow generation time adjustment switch 11 airflow generation Time adjustment switch

Claims (12)

[Claims] 1. An air conditioning system comprising a plurality of blowers, wherein a reference wind direction is provided in a horizontal wind direction component of a wind received by a resident, and an airflow closer to the reference wind direction is provided.
A method for controlling an air conditioning system, characterized by increasing a time ratio of airflow generation. 2. The control method for an air conditioning system according to claim 1, wherein a time ratio of the generation of the airflow is determined according to a wind speed. 3. The control method for an air conditioning system according to claim 1, further comprising means for selecting a reference wind direction by a resident. 4. An air conditioning system comprising a plurality of blowers, wherein an upper limit value of one airflow generation time in the same wind direction is provided. 5. The control method for an air conditioning system according to claim 4, wherein said upper limit value is determined according to a wind speed. 6. An air-conditioning system comprising a plurality of blowers, wherein the air-conditioning system generates a wind in which a horizontal wind direction component of a wind received by a occupant is equal to or greater than a predetermined angle. 7. The air conditioning system according to claim 6, wherein the angles of any two horizontal wind direction components generated by the air conditioning system according to claim 6 are equal to or greater than a predetermined angle. 8. The air flow according to claim 1, wherein a part of the air flow is lower than a room temperature by a predetermined temperature or more.
The air-conditioning system and control method thereof. 9. An air flow having a temperature lower than a predetermined temperature lower than the room temperature.
9. The air conditioning system and control method thereof according to claim 8, wherein an upper limit value is set for each time of airflow generation. 10. The air-conditioning system according to claim 8, wherein a generation time interval from the stop of the airflow lower than the room temperature by a predetermined temperature or more to the re-generation is set to a predetermined time or more. . 11. An air conditioning system comprising a room temperature setting means for setting a room temperature, wherein an airflow generation ratio lower than the room temperature by a predetermined temperature or more is determined according to a difference between the room temperature and the set temperature. An air conditioning system according to any one of claims 10 to 10, and a control method thereof. 12. The air-conditioning system according to claim 8, wherein an airflow lower than the room temperature by a predetermined temperature or more and an airflow other than the airflow lower than the room temperature by a predetermined temperature are not generated at the same time. Method.