Airflow generation system, airflow generation method, and recording medium

Abstract

An airflow generation system includes: an outside air temperature detector that detects an outside air temperature that is a temperature of an outdoor area; an inside air temperature detector that detects an inside air temperature of a space separated from the outdoor area by a structure that is upright; an airflow generation device that generates airflow that flows along the structure from a ceiling to a floor or from the floor to the ceiling in the space; and a control device that controls the airflow generation device based on the outside air temperature detected and the inside air temperature detected.

Description

TECHNICAL FIELD

[0001] The present invention relates to an airflow generation system, an airflow generation method, and a program.BACKGROUND ART

[0002] Various techniques for moderating transfer of heat between two spaces that need to have temperature differences have been proposed. For example, Patent Literature (PTL) 1 discloses an air curtain device including a blowing means that blows out blocking air from the vicinity of the opening edge of a doorway provided in a wall dividing two spaces that may have temperature differences, in a direction across the opening of the doorway to form an air curtain only at substantially the lower half of the doorway.CITATION LISTPatent Literature

[0003] [PTL 1]Japanese Unexamined Patent Application Publication No. 2008-298400SUMMARY OF INVENTIONTechnical Problem

[0004] The present invention provides an airflow generation system, etc. capable of reducing the influence, on an inside air temperature, of the transfer of heat between an outdoor area and a space separated from the outdoor area by a structure.Solution to Problem

[0005] An airflow generation system according to one aspect of the present invention includes: an outside air temperature detector that detects an outside air temperature that is a temperature of an outdoor area; an inside air temperature detector that detects an inside air temperature of a space separated from the outdoor area by a structure that is upright; an airflow generation device that generates airflow that flows along the structure from a ceiling to a floor or from the floor to the ceiling in the space; and a controller that controls the airflow generation device based on the outside air temperature detected and the inside air temperature detected.

[0006] An airflow generation method according to one aspect of the present invention is an airflow generation method executed by a computer, including: detecting an outside air temperature that is a temperature of an outdoor area; detecting an inside air temperature of a space separated from the outdoor area by a structure that is upright; and generating airflow that flows along the structure from a ceiling to a floor or from the floor to the ceiling in the space, by controlling an airflow generation device based on the outside air temperature detected and the inside air temperature detected.

[0007] A program according to one aspect of the present invention is a program for causing a computer to execute the above-described airflow generation method.Advantageous Effects of Invention

[0008] The airflow generation system, etc. according to one aspect of the present invention are capable of reducing the influence, on an inside air temperature, of the transfer of heat between an outdoor area and a space separated from the outdoor area by a structure.BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 is a diagram for describing an outline of an airflow generation system according to an embodiment.

[0010] FIG. 2 is a block diagram illustrating a functional configuration of the airflow generation system according to the embodiment.

[0011] FIG. 3 is a diagram illustrating an installation example of an inside air temperature detector.

[0012] FIG. 4 is a flowchart illustrating a fundamental operation of the airflow generation system according to the embodiment.

[0013] FIG. 5 is a flowchart illustrating an example of the operation of the airflow generation system according to the embodiment.

[0014] FIG. 6 is a diagram for describing an operation of an airflow generation device in step S20 of FIG. 5.

[0015] FIG. 7 is a diagram for describing Variation 1 of a control process.

[0016] FIG. 8 is a diagram for describing Variation 2 of the control process.

[0017] FIG. 9 is a diagram for describing Variation 3 of the control process.DESCRIPTION OF EMBODIMENTS

[0018] Hereinafter, embodiments will be described in detail with reference to the Drawings. It should be noted that the embodiments described below each show a general or specific example. The numerical values, shapes, materials, structural components, the arrangement and connection of the structural components, steps, the processing order of the steps, and so on, shown in the following embodiments are mere examples, and therefore do not limit the present disclosure. Among the structural components in the embodiments described below, those not recited in the independent claims will be described as optional structural components.

[0019] In addition, each of the diagrams is a schematic diagram and not necessarily strictly illustrated. In each of the diagrams, substantially the same structural components are assigned with the same reference signs, and there are instances where redundant descriptions are omitted or simplified.EmbodimentsConfiguration

[0020] First, a configuration of an airflow generation system according to an embodiment will be described. FIG. 1 is a diagram for describing an outline of airflow generation system 100 according to the embodiment. FIG. 2 is a block diagram illustrating a functional configuration of airflow generation system 100 according to the embodiment. FIG. 3 is a diagram illustrating an installation example of inside air temperature detector 2.

[0021] Airflow generation system 100 is a system that detects an outside air temperature and an inside air temperature, and controls airflow generation device 4 that generates airflow that flows along structure 3 from a ceiling to a floor or from the floor to the ceiling, based on the outside air temperature detected and the inside air temperature detected. More specifically, airflow generation system 100 controls the generation of airflow to reduce the influence, on the inside air temperature, of the heat (radiation heat and cold radiation) that transfers via structure 3 between the outside of building 50 (i.e., outdoor area) and space 5 that is inside of building 50.

[0022] The outside air temperature is a temperature of an outdoor area, and detected by outside air temperature detector 1. The inside air temperature is a temperature in space 5 separated from the outdoor area by structure 3 that is upright, and is detected by inside air temperature detector 2.

[0023] Structure 3 is a wall or a window, for example. FIG. 1 illustrates an example in which structure 3 is a window, and FIG. 3 illustrates an example in which structure 3 is a wall. Space 5 is a room, for example, separated from the outdoor area by the wall or the window.

[0024] As illustrated in FIG. 2, airflow generation system 100 includes outside air temperature detector 1, inside air temperature detector 2, airflow generation device 4, and a controller (in this case, control device 10).

[0025] Outside air temperature detector 1 is a sensor that detects an outside air temperature that is a temperature of an outdoor area. Outside air temperature detector 1 is a temperature sensor, for example. The type of the temperature sensor is not particularly limited. Outside air temperature detector 1 transmits data of the outside air temperature detected to control device 10. Outside air temperature detector 1 is, for example, connected to control device 10 via wireless communication or wired communication. For example, as illustrated in FIG. 1, outside air temperature detector 1 is installed in proximity to structure 3 in the outdoor area.

[0026] Inside air temperature detector 2 is a sensor that detects an inside air temperature of space 5 separated from the outdoor area by structure 3 that is upright. Inside air temperature detector 2 may be implemented by a plurality of temperature sensors dispersedly disposed in space 5, or may be implemented by a thermal image sensor that captures a thermal image of space 5. The thermal image sensor is, for example, an infrared array sensor or an infrared camera. For example, when inside air temperature detector 2 is a thermal image sensor, one inside air temperature detector 2 is provided on a ceiling in a space (see FIG. 1), but two or more inside air temperature detectors 2 may be provided (see (a) in FIG. 3). In addition, inside air temperature detector 2 may be provided on a wall instead of the ceiling, or may be also provided on a floor in addition to the ceiling (see (b) in FIG. 3). In addition, for example, inside air temperature detector 2 may be attached to an air conditioner provided in space 5, or may be attached to lighting provided on the ceiling, on the wall, or on the floor in space 5. Inside air temperature detector 2 detects a first inside air temperature in the center area of space 5 and a second inside air temperature in a location closer to structure 3 (for example, wall 3 in (a) and (b) in FIG. 3) than the center area is. In addition, inside air temperature detector 2 detects a third inside air temperature in a location beside the ceiling in space 5 and a fourth inside air temperature in a location beside the floor in space 5. Inside air temperature detector 2 transmits data of the inside air temperatures detected (the first inside air temperature, the second inside air temperature, the third inside air temperature, and the fourth inside air temperature) to control device 10. Inside air temperature detector 2 is, for example, connected to control device 10 via wireless communication or wired communication.

[0027] Airflow generation device 4 is a device that generates airflow that flows along structure 3 from the ceiling to the floor or from the floor to the ceiling in a space. Airflow generation device 4 is connected to and allowed to communicate with control device 10, and is controlled based on a control signal output from control device 10. Airflow generation device 4 includes first airflow generator 4a provided on the ceiling in space 5 and second airflow generator 4b provided on the floor in space 5. More specifically, as illustrated in FIG. 1, first airflow generator 4a and second airflow generator 4b are provided on the ceiling and the floor on the structure 3 side. For example, first airflow generator 4a and second airflow generator 4b may be provided at a predetermined distance (e.g., 5 cm to 10 cm) from structure 3. At this time, first airflow generator 4a and second airflow generator 4b may be arranged, for example, to overlap each other in a top view from the ceiling, or may be arranged by being shifted along structure 3, such that at least part of first airflow generator 4a and second airflow generator 4b overlap each other in the top view. For example, first airflow generator 4a and second airflow generator 4b may be disposed on a ceiling surface and on a floor surface, or may be embedded in the ceiling and the floor. The shape of first airflow generator 4a and second airflow generator 4b may be, for example, an elongated shape extending along structure 3 (see FIG. 1) or a quadrilateral shape or a circular shape such as the shape of a ventilation fan. In addition, first airflow generator 4a and second airflow generator 4b may be provided one by one in space 5, or two or more first airflow generators 4a and two or more second airflow generators 4b may be provided beside structure 3 in space 5. First airflow generator 4a and second airflow generator 4b each include, for example, an air outlet, an air inlet, a fan (e.g., an impeller and a motor to drive the impeller), piping, and a filter. First airflow generator 4a and second airflow generator 4b may each include a single fan that is switchable between for sucking in air and for blowing out air, or include a fan for sucking in air and a fan for blowing out air. Airflow is generated when one of first airflow generator 4a or second airflow generator 4b performs a blow-out operation to blow out air into space 5, and the other of first airflow generator 4a and second airflow generator 4b performs a suck-in operation to suck in air from space 5.

[0028] Control device 10 is an example of a controller and controls airflow generation device 4, based on the outside air temperature detected by outside air temperature detector 1 and the inside air temperature detected by inside air temperature detector 2. Control device 10 includes, for example, communicator 11, control unit 12, and storage 13. Control device 10 may further include an operation receiver (not illustrated) and a display (not illustrated). In the example illustrated in FIG. 1, control device 10 is, for example, a controller attached to a wall surface within space 5, but may also be a controller disposed in building 50 including space 5.

[0029] Communicator 11 is a communication circuit (or a communication module) for use in performing communication by control device 10 with outside air temperature detector 1, inside air temperature detector 2, and airflow generation device 4. Communicator 11 is, for example, a wireless communication circuit for performing wireless communication, but may be a wire communication circuit for performing wire communication. The communication standard for communication performed by communicator 11 is not particularly limited. It should be noted that communicator 11 may perform wireless communication with a mobile terminal (not illustrated) of a user. In this case, communicator 11 may include a communication circuit for performing short-distance wireless communication, may include a communication circuit for performing wireless communication via a wide area communication network, or may include both of these communication circuits. The mobile terminal, upon receiving an instruction of the user, may transmit the instruction to control device 10, or may present a notification from control device 10 to the user.

[0030] Control unit 12 performs information processing for controlling airflow generation device 4, based on the outside air temperature detected by outside air temperature detector 1 and the inside air temperature detected by inside air temperature detector 2. Control unit 12 is implemented, for example, by a microcomputer, but may be implemented by a processor. Control unit 12 includes obtainer 12a, determiner 12b, and outputter 12c as functional structural components. The functions of obtainer 12a, determiner 12b, and outputter 12c are implemented, for example, by executing a computer program stored in storage 13 by a microcomputer, a processor, or the like that constitutes control unit 12.

[0031] Storage 13 is a storage device in which information necessary for controlling airflow generation device 4 is stored. Such information includes a computer program executed by control unit 12. Storage 13 is, for example, implemented by semiconductor memory.

[0032] An operation receiver (not illustrated) receives an operation (manual operation) of the user of airflow generation device 4. The operation receiver is implemented, for example, by a touch panel, but may be implemented by a hardware key, or the like.

[0033] A display (not illustrated) displays an image. The display is implemented, for example, by a display panel such as a liquid crystal panel, an organic electro luminescence (EL) panel, etc.Operation Example

[0034] Next, an example of the operation of airflow generation system 100 will be described. FIG. 4 is a flowchart illustrating fundamental operations of airflow generation system 100 according to the embodiment. FIG. 5 is a flowchart illustrating an example of the operations of airflow generation system 100 according to the embodiment.

[0035] The controller (here, control device 10) of airflow generation system 100, upon receiving an operation of inputting an instruction for starting an operation by the user, outputs (not illustrated) the instruction for starting the operation to outside air temperature detector 1, inside air temperature detector 2, and airflow generation device 4. Here, the example that the controller (hereinafter referred to as control device 10) of airflow generation system 100 receives the operation of inputting the instruction for starting an operation by the user and outputs the instruction for starting the operation has been explained, but the present disclosure is not limited to this example. For example, when control device 10 of airflow generation system 100 starts an operation (e.g., when the operation of a program starts after power feeding to control device 10), an instruction for starting an operation may be output to outside air temperature detector 1, inside air temperature detector 2, and airflow generation device 4.

[0036] Outside air temperature detector 1 detects an outside air temperature that is a temperature of an outdoor area (outside air temperature detection step S01 of FIG. 4 and step S11 of FIG. 5). Outside air temperature detector 1 transmits the outside air temperature detected to control device 10 at a predetermined time interval. It should be noted that the frequency of transmission of data may be determined as appropriate.

[0037] Inside air temperature detector 2 detects an inside air temperature of space 5 separated from the outdoor area by structure 3 that is upright (inside air temperature detection step S02). Inside air temperature detector 2 transmits data of the inside air temperature detected to control device 10. The frequency of transmitting data may be determined as appropriate. It should be noted that outside air temperature detection step S01 and inside air temperature detection step S02 may be carried out in parallel.

[0038] Next, control device 10 of airflow generation system 100 controls airflow generation device 4 based on the outside air temperature detected and the inside air temperature detected, and thereby generates airflow that flows along structure 3 from a ceiling to a floor or from the floor to the ceiling in space 5 (control step S03). Airflow generation device 4 has been described above, and thus is omitted from the description here.

[0039] As described above, airflow generation system 100 controls the generation of airflow based on the outside air temperature and the inside air temperature, and thus it is possible to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5 separated from the outdoor area by structure 3.

[0040] The following describes in more detail the operation of airflow generation system 100 in inside air temperature detection step S02 and control step S03 with reference to FIG. 5.

[0041] Inside air temperature detector 2 detects a first inside air temperature in the center area of space 5 and a second inside air temperature in a location closer to structure 3 than the center area is (S12), and transmits the data of the first inside air temperature detected and the second inside air temperature detected to control device 10.

[0042] Upon obtaining (not illustrated) the data of the first inside air temperature and the second inside air temperature transmitted from inside air temperature detector 2, control device 10 determines whether the second inside air temperature is closer to the outside air temperature than to the first inside air temperature (step S13). When determining that the second inside air temperature is closer to the outside air temperature than to the first inside air temperature (Yes in step S13), control device 10 outputs (not illustrated) an instruction for starting the generation of airflow to airflow generation device 4. Upon obtaining the instruction, airflow generation device 4 starts to generate airflow (step S14). The control of airflow will be described in detail later.

[0043] On the other hand, when determining that the second inside air temperature is not closer to the outside air temperature than to the first inside air temperature (No in step S13), control device 10 causes inside air temperature detector 2 to detect the third inside air temperature in a location beside the ceiling in space 5 and the fourth inside air temperature in a location beside the floor in space 5. Upon detecting the third inside air temperature and the fourth inside air temperature (step S15), inside air temperature detector 2 transmits (not illustrated) the data of the third inside air temperature detected and the fourth inside air temperature detected to control device 10.

[0044] Upon obtaining (not illustrated) the data of the third inside air temperature and the fourth inside air temperature transmitted from inside air temperature detector 2, control device 10 determines whether an absolute value of the difference between the third inside air temperature and the fourth inside air temperature is greater than or equal to a second threshold (step S16). When determining that the absolute value of the difference between the third inside air temperature and the fourth inside air temperature is not greater than or equal to the second threshold (No in step S16), control device 10 returns to the process of step S11. On the other hand, when determining that the absolute value of the difference between the third inside air temperature and the fourth inside air temperature is greater than or equal to the second threshold (Yes in step S16), control device 10 outputs (not illustrated) an instruction for starting the generation of airflow to airflow generation device 4. Upon obtaining the instruction, airflow generation device 4 starts to generate airflow (step S14).

[0045] When airflow generation device 4 starts to generate airflow in step S14, control device 10 determines, for each predetermined period of time (e.g., five minutes), whether the absolute value of the difference between the first inside air temperature and the second inside air temperature is less than or equal to a first threshold (e.g., two) (step S17). As described above, inside air temperature detector 2 transmits the data of the inside air temperature detected to control device 10 at a predetermined time interval. Control device 10 performs the determination described above, based on time series data of the inside air temperature obtained (here, the first inside air temperature and the second inside air temperature). When determining that the absolute value of the difference between the first inside air temperature and the second inside air temperature is less than or equal to the first threshold (Yes in step S17), control device 10 outputs (not illustrated) an instruction for stopping the generation of airflow to airflow generation device 4. Upon obtaining the instruction, airflow generation device 4 stops generating airflow (step S18). In other words, control device 10 causes airflow generation device 4 to continue to generate airflow from when the generation of airflow starts in step S14 until when the absolute value of the difference between the first inside air temperature and the second inside air temperature falls to or below the first threshold. It should be noted that control device 10, upon receiving the operation of inputting, by a user, the instruction for ending the operation, outputs the instruction for ending the operation to outside air temperature detector 1, inside air temperature detector 2, and airflow generation device 4 to cause outside air temperature detector 1, inside air temperature detector 2, and airflow generation device 4 to end the operations (not illustrated), but control device 10 may cause the operations to be ended by the process in step S18.

[0046] On the other hand, upon determining that the absolute value of the difference between the first inside air temperature and the second inside air temperature is not less than or equal to the first threshold (No in step S17), control device 10 determines whether it is within a first period of time (e.g., 10 minutes) from the start of the generation of airflow (step S19). Upon determining that it is within the first period of time from the start of the generation of airflow (Yes in step S19), control device 10 outputs (not illustrated) an instruction to airflow generation device 4 for (i) increasing the strength of airflow stepwise, (ii) reversing the direction of airflow, or (iii) causing first airflow generator 4a and second airflow generator 4b to perform the same operation (e.g., blow-out operation or suck-in operation). Upon obtaining the above-described instruction, airflow generation device 4 (i) increases the strength of airflow stepwise, (ii) reverses the direction of airflow, or (iii) causes first airflow generator 4a and second airflow generator 4b to perform the same operation (e.g., blow-out operation or suck-in operation) (step S20). FIG. 6 is a diagram for describing an operation of airflow generation device 4 in step S20 of FIG. 5. In FIG. 6, in consideration of visibility, illustration of reference sign 4 is omitted. In FIG. 6, (a) and (b) schematically illustrate the example of the above-described (ii) in which airflow generation device 4 reverses the direction of airflow, and (c) and (d) schematically illustrate the example of the above-described (iii) in which first airflow generator 4a and second airflow generator 4b perform the same operation. In FIG. 6, structure 3 is a wall, and the operation of blowing out air to space 5 and the operation or sucking in air from space 5 performed by first airflow generator 4a and second airflow generator 4b are schematically illustrated by open arrows.

[0047] First, the reversing of airflow in the above-described (ii) will be described. For example, as illustrated in (a) of FIG. 6, when first airflow generator 4a of airflow generation device 4 performs the blow-out operation of blowing out air to space 5 and second airflow generator 4b performs the suck-in operation of sucking in air from space 5, airflow that flows from the ceiling side to the floor side is generated. At this time, when airflow generation device 4 obtains the instruction for reversing the direction of the airflow from control device 10, first airflow generator 4a switches from the blow-out operation to the suck-in operation and second airflow generator 4b switches from the suck-in operation to the blow-out operation according to the above-described instruction as illustrated in (b) of FIG. 6, thereby reversing the direction of the airflow. In this manner, airflow generation device 4 reverses the airflow that flows from the ceiling side to the floor side, and thereby generates the airflow that flows from the floor side to the ceiling side.

[0048] Next, the operation in the above-described (iii) will be described. For example, when airflow generation device 4 obtains, from control device 10, the instruction for causing each of first airflow generator 4a and second airflow generator 4b to perform the blow-out operation, first airflow generator 4a and second airflow generator 4b both perform the blow-out operation according to the above-described instruction as illustrated in (c) of FIG. 6. In this manner, airflow generation system 100 is capable of circulating air by pushing air in a location close to structure 3 (e.g., wall 3) in space 5 to a location close to the center area in space 5. As a result, it is possible to facilitate bringing the absolute value of the difference between the first inside air temperature and second inside air temperature to or below the first threshold. In addition, for example, when airflow generation device 4 obtains, from control device 10, the instruction for causing first airflow generator 4a and second airflow generator 4b to both perform the suck-in operation, first airflow generator 4a and second airflow generator 4b both perform the suck-in operation according to the above-described instruction as illustrated in (d) of FIG. 6. In this manner, airflow generation system 100 is capable of circulating air by drawing air in the location close to the center area in space 5 to the location close to structure 3 (wall 3) in space 5. As a result, it is possible to facilitate bringing the absolute value of the difference between the first inside air temperature and second inside air temperature to or below the first threshold.

[0049] Control device 10 of airflow generation system 100 returns to step S17 after step S20. On the other hand, upon determining that it is not within the first period of time from the start of the generation of airflow (No in step S19), control device 10 determines whether it is within a second period of time (e.g., 60 minutes) from the start of the generation of airflow (step S21). It should be noted that the second period of time is longer than the first period of time. Here, the example in which the first period of time is 10 minutes and the second period of time is 60 minutes has been described, but the present disclosure is not limited to this example. These periods of time can vary according to, for example, the amount of moisture contained in the air, the temperature of the air, etc., and thus may be set experimentally or empirically. Upon determining that it is within the second period of time from the start of the generation of airflow (Yes in step S21), control device 10 returns to step S17. On the other hand, upon determining that it is not within the second period of time from the start of the generation of airflow (No in step S21), control device 10 outputs (not illustrated) an instruction for stopping generating airflow to airflow generation device 4. Upon obtaining the instruction, airflow generation device 4 stops generating airflow (step S18).

[0050] As described above, airflow generation system 100 starts the generation of airflow when transfer of heat is occurring between the outdoor area and space 5 via structure 3 (wall 3), and thus it is possible to reduce the influence of the transfer of heat on the inside air temperature.

[0051] In addition, airflow generation system 100 is capable of reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5, by continuing the generation of airflow until the temperature difference between the center area of space 5 and the location close to structure 3 (wall 3) becomes the degree to which a human sensible temperature barely changes. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5.

[0052] In addition, airflow generation system 100 is capable of bringing, in a shorter period of time, the above-described difference close to the temperature difference to the degree to which a human sensible temperature barely changes, by increasing the strength of airflow stepwise, reversing the direction of airflow, or causing both first airflow generator 4a and second airflow generator 4b to perform the same operation (to be specific, the blow-out operation or the suck-in operation) after the first period of time (e.g., 10 minutes) has elapsed. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5 even in the case where it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5.

[0053] In addition, when it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5 within the second period of time (e.g., 60 minutes), airflow generation system 100 stops the generation of airflow, thereby making it possible to reduce the load and costs of airflow generation device 4.

[0054] In addition, when either warm air stagnation in a location beside the ceiling in space 5 or cold air stagnation in a location beside the floor in space 5 is generated, airflow generation system 100 is capable of reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5, by using either the air of the warm air stagnation at the third inside air temperature or the air of the cold air stagnation at the fourth inside air temperature so as to start the generation of airflow.Variation 1 of the Control Process

[0055] Next, Variation 1 of the control process of airflow generation system 100 will be described. FIG. 7 is a diagram for describing Variation 1 of the control process. In FIG. 7, structure 3 is a wall, and airflow generated along structure 3 (e.g., wall 3) by the operations of first airflow generator 4a and second airflow generator 4b is schematically illustrated by open arrows. In addition, in FIG. 7, the transfer of heat between the outdoor area and space 5 that is occurring via structure 3 (wall 3) is indicated by dotted arrows.

[0056] Control device 10 obtains an outside air temperature detected by outside air temperature detector 1 and an inside air temperature detected by inside air temperature detector 2. When the outside air temperature is higher than the inside air temperature, control device 10 causes airflow generation device 4 to generate, for example, airflow that flows from the floor toward the ceiling as illustrated in (a) of FIG. 7. When the outside air temperature is lower than the inside air temperature, control device 10 causes airflow generation device 4 to generate, for example, airflow that flows from the ceiling toward the floor as illustrated in (b) of FIG. 7. At this time, the inside air temperature may be the second inside air temperature in the center area of space 5, or may be the first inside air temperature in the location close to structure 3 (wall 3) of space 5.

[0057] As described above, airflow generation system 100 is capable of generating airflow that flows toward the ceiling, using the air of cold air stagnation A2 at the fourth inside air temperature in the location beside the floor in space 5 when the outside air temperature is higher than the inside air temperature, and generating airflow that flows toward the floor, using the air of warm air stagnation A1 at the third inside air temperature in the location beside the ceiling in space 5 when the outside air temperature is lower than the inside air temperature. In this manner, airflow generation system 100 can block the transfer of heat (radiation heat or cold radiation) between the outdoor area and space 5, and thus makes it possible to reduce the influence of the transfer of heat on the inside air temperature.Variation 2 of the Control Process

[0058] Next, Variation 2 of the control process of airflow generation system 100 will be described. FIG. 8 is a diagram for describing Variation 2 of the control process. In FIG. 8, structure 3 is a wall, and airflow generated along structure 3 (e.g., wall 3) by the operations of first airflow generator 4a and second airflow generator 4b is schematically illustrated by open arrows. In addition, in FIG. 8, the convection flow generated along structure 3 (wall 3) by the transfer of heat between the outdoor area and space 5 is indicated by dotted arrows.

[0059] Control device 10 obtains an outside air temperature detected by outside air temperature detector 1 and an inside air temperature detected by inside air temperature detector 2. When the outside air temperature is higher than the inside air temperature, control device 10 causes airflow generation device 4 to generate, for example, airflow that flows from the ceiling toward the floor as illustrated in FIG. (a) of FIG. 8. When the outside air temperature is lower than the inside air temperature, control device 10 causes airflow generation device 4 to generate, for example, airflow that flows from the floor toward the ceiling as illustrated in (b) of FIG. 8. At this time, the inside air temperature may be the second inside air temperature in the center area of space 5, or may be the first inside air temperature in the location close to structure 3 (wall 3) of space 5.

[0060] As described above, airflow generation system 100 is capable of generating airflow that flows toward the floor, using the air of warm air stagnation A1 at the third inside air temperature in the location beside the ceiling in space 5 when the outside air temperature is higher than the inside air temperature, and generating airflow that flows toward the ceiling, using the air of cold air stagnation A2 at the fourth inside air temperature in the location beside the floor in space 5 when the outside air temperature is lower than the inside air temperature. In this manner, airflow generation system 100 can counteract the convection flow of the warm air or the cold air generated along structure 3 (wall 3) by the transfer of heat (radiation heat or cold radiation) between the outdoor area and space 5, and thus makes it possible to reduce the influence of the transfer of heat on the inside air temperature.Variation 3 of the Control Process

[0061] Next, Variation 3 of the control process of airflow generation system 100 will be described. FIG. 9 is a diagram for describing Variation 3 of the control process. In FIG. 9, structure 3 is a wall, and airflow generated by the operations of first airflow generator 4a and second airflow generator 4b is schematically illustrated by open arrows.

[0062] In Variation 3, the distance from structure 3 (e.g., wall 3) to first airflow generator 4a and the distance from structure 3 to second airflow generator 4b are individually settable. For example, as illustrated in (a) of FIG. 9 to (c) of FIG. 9, in regard to first airflow generator 4a provided on the ceiling in space 5, the distance from structure 3 (wall 3) to the center of first airflow generator 4a is X1, and in regard to second airflow generator 4b provided on the floor in space 5, the distance from structure 3 (wall 3) to the center of second airflow generator 4b is X2 provided on the floor in space 5. In the example illustrated in FIG. 9, X1<X2, but it may be X1=X2, or may be X1>X2. The numerical range that X1 and X2 can take may be, for example, at least 0 cm and at most 30 cm. These ranges are not particularly limited to the examples described above, but may be set as appropriate according to the sizes of first airflow generator 4a and second airflow generator 4b. In addition, these ranges may be set experimentally or empirically. It should be noted that, although the above-described X1 and X2 are the distance from structure 3 (wall 3) to the center of first airflow generator 4a and the distance from structure 3 to the center of second airflow generator 4b, respectively, they need not necessarily distances to the center. For example, X1 may be the distance from structure 3 (wall 3) to the end (side face) of first airflow generator 4a on the side facing structure 3 (wall 3), and X2 may be the distance from structure 3 (wall 3) to the end (side face) of second airflow generator 4b on the side facing structure 3 (wall 3).

[0063] Each of first airflow generator 4a and second airflow generator 4b is capable of performing a blow-out operation to send air into space 5 and a suck-in operation to draw in air from space 5. The direction of blowing out air in the blow-out operation and the direction of sucking in air in the suck-in operation are variable. For example, as illustrated in (a) of FIG. 9, control device 10 causes both first airflow generator 4a and second airflow generator 4b to perform the blow-out operation, but may cause them to perform the suck-in operation.

[0064] In addition, for example, as illustrated in (b) of FIG. 9, control device 10 causes first airflow generator 4a to perform the blow-out operation, and causes second airflow generator 4b to perform the suck-in operation. At this time, first airflow generator 4a changes the direction of blowing out air in the blow-out operation to the direction toward second airflow generator 4b, and second airflow generator 4b changes the direction of sucking in air in the suck-in operation to the direction toward first airflow generator 4a.

[0065] In addition, for example, as illustrated in (c) of FIG. 9, control device 10 causes first airflow generator 4a to perform the suck-in operation, and causes second airflow generator 4b to perform the blow-out operation. At this time, first airflow generator 4a changes the direction of sucking in air in the suck-in operation to the direction toward second airflow generator 4b, and second airflow generator 4b changes the direction of blowing out air in the blow-out operation to the direction toward first airflow generator 4a.

[0066] As described above, in airflow generation system 100, in a top view from the ceiling, first airflow generator 4a and second airflow generator 4b can be arranged to overlap each other, or can be arranged by being shifted in a direction from structure 3 (wall 3) to the center area of space 5 so as not to overlap each other. Thus, airflow generation system 100 is capable of generating airflow or convection flow at a position shifted by an intended width in a direction from structure 3 (wall 3) to the center area of space 5. As a result, airflow generation system 100 is capable of efficiently reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5. Furthermore, since the direction of blowing out air in the blow-out operation and the direction of sucking in air in the suck-in operation performed by first airflow generator 4a and second airflow generator 4b are variable, airflow generation system 100 is capable of generating airflow in such a manner that airflow does not reach structure 3 (wall 3). Thus, airflow generation system 100 can make it difficult to form condensation on the surface of structure 3 (wall 3). As a result, airflow generation system 100 is capable of providing a comfortable environment for a person present in space 5.Advantageous Effects, Etc.

[0067] Hereinafter, inventions that can be achieved from the disclosure of this Description will be exemplified, and advantageous effects, etc., yielded from the inventions exemplified will be described.

[0068] Invention 1 is directed to airflow generation system 100 including: outside air temperature detector 1 that detects an outside air temperature that is a temperature of an outdoor area (e.g., the outside of building 50); inside air temperature detector 2 that detects an inside air temperature of space 5 separated from the outdoor area by structure 3 that is upright; airflow generation device 4 that generates airflow that flows along structure 3 from a ceiling to a floor or from the floor to the ceiling in space 5; and a controller (e.g., control device 10) that controls airflow generation device 4 based on the outside air temperature detected and the inside air temperature detected.

[0069] Such airflow generation system 100 as described above controls the generation of airflow based on the outside air temperature and the inside air temperature, and thus it is possible to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5 separated from the outdoor area by structure 3.

[0070] Invention 2 is directed to airflow generation system 100 according to Invention 1. In airflow generation system 100, inside air temperature detector 2 detects a first inside air temperature in a center area of space 5 and a second inside air temperature in a location closer to structure 3 than the center area of space 5 is, and control device 10 causes airflow generation device 4 to start to generate the airflow when the second inside air temperature is closer to the outside air temperature than to the first inside air temperature.

[0071] Such airflow generation system 100 as described above starts the generation of airflow when transfer of heat is occurring between the outdoor area and space 5 via structure 3, and thus it is possible to reduce the influence of the transfer of heat on the inside air temperature.

[0072] Invention 3 is directed to airflow generation system 100 according to Invention 2. In airflow generation system 100, control device 10 causes airflow generation device 4 to continue to generate the airflow from when airflow generation device 4 starts to generate the airflow until when an absolute value of a difference between the first inside air temperature and the second inside air temperature falls to or below a first threshold (e.g., two).

[0073] Such airflow generation system 100 as described above is capable of reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5, by continuing the generation of airflow until the temperature difference between the center area of space 5 and the location close to structure 3 becomes the degree to which a human sensible temperature barely changes. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5.

[0074] Invention 4 is directed to airflow generation system 100 according to Invention 3. In airflow generation system 100, control device 10 causes airflow generation device 4 to increase a strength of the airflow stepwise when the absolute value of the difference does not fall to or below the first threshold (e.g., two) within a first period of time (e.g., 10 minutes) from when airflow generation device 4 starts to generate the airflow.

[0075] Such airflow generation system 100 as described above is capable of bringing, in a shorter period of time, the above-described difference close to the temperature difference to the degree to which a human sensible temperature barely changes, by increasing the strength of airflow stepwise after the first period of time (e.g., 10 minutes) has elapsed. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5 even in the case where it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5.

[0076] Invention 5 is directed to airflow generation system 100 according to Invention 4. In airflow generation system 100, control device 10 causes airflow generation device 4 to reverse a direction of the airflow when the absolute value of the difference does not fall to or below the first threshold (e.g., two) within the first period of time (e.g., 10 minutes) from when airflow generation device 4 starts to generate the airflow.

[0077] Such airflow generation system 100 as described above is capable of bringing the above-described difference close to the temperature difference to the degree to which a human sensible temperature barely changes, using the air in the location beside the ceiling in space 5 or the air in the location beside the floor in space 5 for example, by reversing the direction of airflow after the first period of time (e.g., 10 minutes) has elapsed. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5 even in the case where it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5.

[0078] Invention 6 is directed to airflow generation system 100 according to Invention 4. In airflow generation system 100, airflow generation device 4 includes first airflow generator 4a disposed on the ceiling in space 5 and second airflow generator 4b disposed on the floor in space 5, the airflow is generated by a blow-out operation of blowing out air to space 5 performed by one of first airflow generator 4a or second airflow generator 4b and a suck-in operation of sucking in air from space 5 performed by an other of first airflow generator 4a or second airflow generator 4b, and control device 10 causes both first airflow generator 4a and second airflow generator 4b to perform the blow-out operation or causes both first airflow generator 4a and second airflow generator 4b to perform the suck-in operation when the absolute value of the difference does not fall to or below the first threshold (e.g., two) within the first period of time (e.g., 10 minutes) from when airflow generation device 4 starts to generate the airflow.

[0079] Such airflow generation system 100 as described above is capable of generating convection flow at a location beside structure 3 in space 5, by causing both first airflow generator 4a and second airflow generator 4b to perform the same operation (blow-out operation or suck-in operation). In this manner, air is drawn to the location beside structure 3 in space 5 from another location in space 5 (e.g., location beside the ceiling, location beside the floor, and the center area, etc.), which facilitates bringing the above-described difference to or below the first threshold. As a result, airflow generation system 100 is capable of providing a comfortable air-conditioned environment for a person present in space 5 even in the case where it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5.

[0080] Invention 7 is directed to airflow generation system 100 according to any one of Inventions 4 to 6. In airflow generation system 100, control device 10 causes airflow generation device 4 to stop generating the airflow when the absolute value of the difference does not fall to or below first threshold (e.g., two) within a second period of time (e.g., 60 minutes) from when airflow generation device 4 starts to generate the airflow, and the second period of time is longer than the first period of time.

[0081] When it is difficult to reduce the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5 within the second period of time (e.g., 60 minutes), such airflow generation system 100 as described above stops the generation of airflow, thereby making it possible to reduce the load and costs of airflow generation device 4.

[0082] Invention 8 is directed to airflow generation system 100 according to Invention 2. In airflow generation system 100, inside air temperature detector 2 detects a third inside air temperature in a location beside the ceiling in space 5 and a fourth inside air temperature in a location beside the floor in space 5, and control device 10 causes airflow generation device 4 to start to generate the airflow when an absolute value of a difference between the third inside air temperature and the fourth inside air temperature is greater than or equal to a second threshold (e.g., five).

[0083] When either warm air stagnation in a location beside the ceiling in space 5 or cold air stagnation in a location beside the floor in space 5 is generated, such airflow generation system 100 as described above is capable of reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5, by using either the air of the warm air stagnation at the third inside air temperature or the air of the cold air stagnation at the fourth inside air temperature so as to start the generation of airflow.

[0084] Invention 9 is directed to airflow generation system 100 according to Invention 1. In airflow generation system 100, control device 10 causes airflow generation device 4 to generate the airflow flowing from the floor toward the ceiling when the outside air temperature is higher than the inside air temperature; and causes airflow generation device 4 to generate the airflow flowing from the ceiling toward the floor when the outside air temperature is lower than the inside air temperature.

[0085] Such airflow generation system 100 as described above is capable of generating airflow that flows toward the ceiling, using the air of the cold air stagnation at the fourth inside air temperature in the location beside the floor in space 5 when the outside air temperature is higher than the inside air temperature, and generating airflow that flows toward the floor, using the air of the warm air stagnation at the third inside air temperature in the location beside the ceiling in space 5 when the outside air temperature is lower than the inside air temperature. In this manner, airflow generation system 100 can block the transfer of heat (radiation heat or cold radiation) between the outdoor area and space 5, and thus makes it possible to reduce the influence of the transfer of heat on the inside air temperature.

[0086] Invention 10 is directed to airflow generation system 100 according to Invention 1. In airflow generation system 100, control device 10 causes airflow generation device 4 to generate the airflow flowing from the ceiling toward the floor when the outside air temperature is higher than the inside air temperature; and causes airflow generation device 4 to generate the airflow flowing from the floor toward the ceiling when the outside air temperature is lower than the inside air temperature.

[0087] Such airflow generation system 100 as described above is capable of generating airflow that flows toward the floor, using the air of the warm air stagnation at the third inside air temperature in the location beside the ceiling in space 5 when the outside air temperature is higher than the inside air temperature, and generating airflow that flows toward the ceiling, using the air of the cold air stagnation at the fourth inside air temperature in the location beside the floor in space 5 when the outside air temperature is lower than the inside air temperature. In this manner, airflow generation system 100 can counteract the convection flow of the warm air or the cold air generated along structure 3 by the transfer of heat (radiation heat or cold radiation) between the outdoor area and space 5, and thus makes it possible to reduce the influence of the transfer of heat on the inside air temperature.

[0088] Invention 11 is directed to airflow generation system 100 according to any one of Inventions 1 to 10. In airflow generation system 100, airflow generation device 4 includes first airflow generator 4a disposed on the ceiling in space 5 and second airflow generator 4b disposed on the floor in space 5, first airflow generator 4a and second airflow generator 4b are each configured to perform a blow-out operation of blowing out air into space 5 and a suck-in operation of sucking in air from space 5, and a direction of blowing out air in the blow-out operation and a direction of sucking in air in the suck-in operation are variable, and a distance between first airflow generator 4a and structure 3 and a distance between second airflow generator 4b and structure 3 are individually settable.

[0089] In such airflow generation system 100 as described above, in a top view from the ceiling, first airflow generator 4a and second airflow generator 4b can be arranged to overlap each other, or can be arranged by being shifted in a direction from structure 3 to the center area of space 5 so as not to overlap each other. Thus, airflow generation system 100 is capable of generating airflow or convection flow at a position shifted by an intended width in the direction from structure 3 to the center area in space 5. As a result, airflow generation system 100 is capable of efficiently reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5. Furthermore, since the direction of blowing out air in the blow-out operation and the direction of sucking in air in the suck-in operation performed by first airflow generator 4a and second airflow generator 4b are variable, airflow generation system 100 is capable of generating airflow in such a manner that airflow does not reach structure 3. Thus, airflow generation system 100 can make it difficult to form condensation on the surface of structure 3. As a result, airflow generation system 100 is capable of providing a comfortable environment for a person present in space 5.

[0090] Invention 12 is directed to airflow generation system 100 according to any one of Inventions 1 to 10. In airflow generation system 100, airflow generation device 4 includes first airflow generator 4a disposed on the ceiling in space 5 and second airflow generator 4b disposed on the floor in space 5, and control device 10 causes airflow generation device 4a to generate the airflow by causing one of first airflow generator 4a or second airflow generator 4b to perform a blow-out operation of blowing out air into space 5 and causing an other of first airflow generator 4a or second airflow generator 4b to perform a suck-in operation of sucking in air from space 5, in a state in which a distance between first airflow generator 4a and structure 3 and a distance between second airflow generator 4b and structure 3 differ from each other.

[0091] Is such airflow generation system 100 as described above, in a top view from the ceiling, first airflow generator 4a and second airflow generator 4b are arranged by being shifted in a direction from structure 3 to the center area of space 5 so as not to overlap each other, and it is thus possible to generate airflow that flows from first airflow generator 4a toward second airflow generator 4b or generate airflow that flows from second airflow generator 4b toward first airflow generator 4a. As a result, airflow generation system 100 is capable of eliminating the warm air stagnation and the cold air stagnation while reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5, by causing air in the location beside structure 3 to transfer, using air in the warm air stagnation in the location beside the ceiling or air in the cold air stagnation in the location beside the floor.

[0092] Invention 13 is directed to airflow generation system 100 according to any one of Inventions 1 to 12. In airflow generation system 100, structure 3 is a wall or a window.

[0093] Such airflow generation system 100 as described above is capable of reducing the influence, on the inside air temperature, of the transfer of heat between the outdoor area and space 5 separated from the outdoor area by a wall or a window.

[0094] Invention 14 is directed to airflow generation system 100 according to any one of Inventions 1 to 13. In airflow generation system 100, inside air temperature detector 2 includes a plurality of temperature sensors dispersedly disposed in space 5.

[0095] Such airflow generation system 100 as described above is capable of obtaining temperature distribution data in space 5, based on inside air temperatures at a plurality of locations in space 5 detected by a plurality of temperature sensors.

[0096] Invention 15 is directed to airflow generation system 100 according to any one of Inventions 1 to 13. In airflow generation system 100, inside air temperature detector 2 includes a thermal image sensor that captures a thermal image of space 5.

[0097] Such airflow generation system 100 as described above is capable of obtaining, by simply providing a single thermal image sensor in space 5 that captures a thermal image of space 5, temperature distribution data in space 5, based on the thermal image.

[0098] Invention 16 is directed to an airflow generation method executed by a computer such as airflow generation system 100. The airflow generation method includes: outside air temperature detection step S01 of detecting an outside air temperature that is a temperature of an outdoor area (e.g., the outside of building 50); inside air temperature detection step S02 of detecting an inside air temperature of space 5 separated from the outdoor area by structure 3 that is upright; and control step S03 of generating airflow that flows along structure 3 from a ceiling to a floor or from the floor to the ceiling in space 5, by controlling airflow generation device 4 based on the outside air temperature detected and the inside air temperature detected.

[0099] With such an airflow generation method as described above, it is possible to cause airflow generation device 4 to generate airflow that flows along structure 3 in a predetermined direction, thereby making it possible to reduce the influence, on the inside air temperature, of transfer of heat between the outdoor area and space 5 separated from the outdoor area by structure 3.

[0100] Invention 17 is directed to a program for causing the computer to execute the airflow generation method according to Invention 16.

[0101] With such a program as described above, it is possible to cause airflow generation device 4 to generate airflow that flows along structure 3 in a predetermined direction, based on the outside air temperature and the inside air temperature, thereby making it possible to reduce the influence, on the inside air temperature, of transfer of heat between the outdoor area and space 5 separated from the outdoor area by structure 3.OTHER EMBODIMENTS

[0102] Although the embodiment has been described thus far, the present invention is not limited to the above-described embodiment.

[0103] For example, in the foregoing embodiment, the airflow generation system may be implemented by a single device, or may be implemented by a plurality of devices. For example, the airflow generation system may be implemented as a single device corresponding to a control device. When the airflow generation system is implemented by a plurality of devices, the structural components (in particular, the functional structural components) included in the airflow generation system may be distributed in any manner to the plurality of devices. For example, in the foregoing embodiment, functional structural components included by the control device (obtainer, determiner, outputter) may be included by the airflow generation device.

[0104] In addition, the method of communication between the devices in the foregoing embodiment is not specifically limited. In addition, a relay device which is not illustrated in the diagrams may intervene in the communication between the devices.

[0105] In addition, in the above-described embodiment, a process performed by a specific processing unit may be performed by a different processing unit. Furthermore, the order of a plurality of processes may be rearranged. Alternatively, the plurality of processes may be performed in parallel.

[0106] In addition, each of the structural components in the above-described embodiment may be implemented by executing a software program suitable for the structural component. Each of the structural components may be implemented by means of a program executing unit, such as a central processing unit (CPU) or a processor, reading and executing the software program recorded on a recording medium such as a hard disk or a semiconductor memory.

[0107] In addition, each of the structural components may be implemented by hardware. For example, each of the structural components may be a circuitry (or an integrated circuit). The circuitries may be configured as a single circuitry as a whole or may be mutually different circuitries. In addition, the circuitries may each be a general-purpose circuit, or may be a dedicated circuit.

[0108] In addition, the generic or specific aspects of the present invention may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a compact disc read only memory (CD-ROM). Alternatively, the generic or specific aspects of the present invention may be implemented by any combination of systems, devices, methods, integrated circuits, computer programs, and recording medium.

[0109] For example, the present invention may be implemented as an airflow generation device or a control device according to the above-described embodiment. In addition, the present invention may be implemented as an airflow generation method executed by a computer such as the airflow generation system, or may be implemented as a program for causing a computer to execute such an airflow generation method. The present invention may be implemented as a non-transitory computer-readable recording medium having recorded thereon such a program as described above.

[0110] It should be noted that the present invention also includes other forms in which various modifications apparent to those skilled in the art are applied to the embodiment or forms in which structural components and functions in the embodiment are arbitrarily combined within the scope of the present invention.REFERENCE SIGNS LIST1 outside air temperature detector

[0112] 2 inside air temperature detector

[0113] 3 structure (wall)

[0114] 4 airflow generation device

[0115] 4a first airflow generator

[0116] 4b second airflow generator

[0117] 5 space

[0118] 10 control device

[0119] 100 airflow generation system

Claims

1. An airflow generation system comprising:an outside air temperature detector that detects an outside air temperature that is a temperature of an outdoor area;an inside air temperature detector that detects an inside air temperature of a space separated from the outdoor area by a structure that is upright;an airflow generation device that generates airflow that flows along the structure from a ceiling to a floor or from the floor to the ceiling in the space; anda controller that controls the airflow generation device based on the outside air temperature detected and the inside air temperature detected.

2. The airflow generation system according to claim 1, whereinthe inside air temperature detector detects a first inside air temperature in a center area of the space and a second inside air temperature in a location closer to the structure than the center area of the space is, andthe controller causes the airflow generation device to start to generate the airflow when the second inside air temperature is closer to the outside air temperature than to the first inside air temperature.

3. The airflow generation system according to claim 2, whereinthe controller causes the airflow generation device to continue to generate the airflow from when the airflow generation device starts to generate the airflow until when an absolute value of a difference between the first inside air temperature and the second inside air temperature falls to or below a first threshold.

4. The airflow generation system according to claim 3, whereinthe controller causes the airflow generation device to increase a strength of the airflow stepwise when the absolute value of the difference does not fall to or below the first threshold within a first period of time from when the airflow generation device starts to generate the airflow.

5. The airflow generation system according to claim 4, whereinthe controller causes the airflow generation device to reverse a direction of the airflow when the absolute value of the difference does not fall to or below the first threshold within the first period of time from when the airflow generation device starts to generate the airflow.

6. The airflow generation system according to claim 4, whereinthe airflow generation device includes a first airflow generator disposed on the ceiling in the space and a second airflow generator disposed on the floor in the space,the airflow is generated by a blow-out operation of blowing out air to the space performed by one of the first airflow generator or the second airflow generator and a suck-in operation of sucking in air from the space performed by an other of the first airflow generator or the second airflow generator, andthe controller causes both the first airflow generator and the second airflow generator to perform the blow-out operation or causes both the first airflow generator and the second airflow generator to perform the suck-in operation when the absolute value of the difference does not fall to or below the first threshold within the first period of time from when the airflow generation device starts to generate the airflow.

7. The airflow generation system according to claim 4, whereinthe controller causes the airflow generation device to stop generating the airflow when the absolute value of the difference does not fall to or below the first threshold within a second period of time from when the airflow generation device starts to generate the airflow, andthe second period of time is longer than the first period of time.

8. The airflow generation system according to claim 2, whereinthe inside air temperature detector detects a third inside air temperature in a location beside the ceiling in the space and a fourth inside air temperature in a location beside the floor in the space, andthe controller causes the airflow generation device to start to generate the airflow when an absolute value of a difference between the third inside air temperature and the fourth inside air temperature is greater than or equal to a second threshold.

9. The airflow generation system according to claim 1, whereinthe controller:causes the airflow generation device to generate the airflow flowing from the floor toward the ceiling when the outside air temperature is higher than the inside air temperature; andcauses the airflow generation device to generate the airflow flowing from the ceiling toward the floor when the outside air temperature is lower than the inside air temperature.

10. The airflow generation system according to claim 1, whereinthe controller:causes the airflow generation device to generate the airflow flowing from the ceiling toward the floor when the outside air temperature is higher than the inside air temperature; andcauses the airflow generation device to generate the airflow flowing from the floor toward the ceiling when the outside air temperature is lower than the inside air temperature.

11. The airflow generation system according to claim 1, whereinthe airflow generation device includes a first airflow generator disposed on the ceiling in the space and a second airflow generator disposed on the floor in the space,the first airflow generator and the second airflow generator are each configured to perform a blow-out operation of blowing out air into the space and a suck-in operation of sucking in air from the space, and a direction of blowing out air in the blow-out operation and a direction of sucking in air in the suck-in operation are variable, anda distance between the first airflow generator and the structure and a distance between the second airflow generator and the structure are individually settable.

12. The airflow generation system according to claim 1, whereinthe airflow generation device includes a first airflow generator disposed on the ceiling in the space and a second airflow generator disposed on the floor in the space, andthe controller causes the airflow generation device to generate the airflow by causing one of the first airflow generator or the second airflow generator to perform a blow-out operation of blowing out air into the space and causing an other of the first airflow generator or the second airflow generator to perform a suck-in operation of sucking in air from the space, in a state in which a distance between the first airflow generator and the structure and a distance between the second airflow generator and the structure differ from each other.

13. The airflow generation system according to claim 1, whereinthe structure is a wall or a window.

14. The airflow generation system according to claim 1, whereinthe inside air temperature detector includes a plurality of temperature sensors dispersedly disposed in the space.

15. The airflow generation system according to claim 1, whereinthe inside air temperature detector includes a thermal image sensor that captures a thermal image of the space.

16. An airflow generation method executed by a computer, comprising:detecting an outside air temperature that is a temperature of an outdoor area;detecting an inside air temperature of a space separated from the outdoor area by a structure that is upright; andgenerating airflow that flows along the structure from a ceiling to a floor or from the floor to the ceiling in the space, by controlling an airflow generation device based on the outside air temperature detected and the inside air temperature detected.

17. A non-transitory computer-readable recording medium having recorded thereon a computer program for causing the computer to execute the airflow generation method according to claim 16.

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