Air conditioning system and crop cultivation system

Abstract

To provide an air-conditioning system or the like capable of supplying conditioned air to crop plants more uniformly.SOLUTION: An air-conditioning system is provided. The air-conditioning system comprises: an air-conditioning unit which sends out conditioned air; a first ventilation duct; a second ventilation duct; and air blowers provided for the second ventilation duct. The first ventilation duct is provided at a position lower than the height of crop plants in a raising space for raising the crop plants. The second ventilation duct is provided at a position higher than the height of the crop plants in the raising space. The air-conditioning unit is installed in an air-conditioning space having a partition between the raising space and the air-conditioning space, and sends out conditioned air into the first ventilation duct. The first ventilation duct discharges the sent-out conditioned air into the raising space. The air blowers send air in the raising space into the second ventilation duct, and the second ventilation duct discharges air sent from the air blowers into the air-conditioning space.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an air conditioning system and a crop cultivation system.

Background Art

[0002] Patent Document 1 discloses a technique of taking in and dehumidifying the air inside a vinyl house and sending the dehumidified air into the vinyl house by a blower.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When supplying conditioned air such as dehumidified air in a space for cultivating crops such as a vinyl house, if there is unevenness in the state of the air in the space, unevenness may occur in the degree of crop growth.

[0005] In view of the above circumstances, the present invention aims to provide an air conditioning system or the like that can supply conditioned air to crops more uniformly.

Means for Solving the Problems

[0006] According to one aspect of the present invention, an air conditioning system is provided. This air conditioning system comprises an air conditioning unit that delivers conditioned air, a first vent pipe, a second vent pipe, and a blower provided in the second vent pipe. The first vent pipe is installed in a growing space for growing crops at a position lower than the height of the crops. The second vent pipe is installed in a growing space at a position higher than the height of the crops. The air conditioning unit is installed in an air conditioning space separated from the growing space by a partition and delivers conditioned air into the first vent pipe. The first vent pipe discharges the delivered conditioned air into the growing space. The blower draws air from the growing space into the second vent pipe, and the second vent pipe discharges the air drawn in by the blower into the air conditioning space.

[0007] In this configuration, the regulated air can be supplied to the crops more uniformly. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the overall configuration of crop cultivation system 1. [Figure 2] This figure shows an example of a crop cultivation system 1 viewed in the depth direction. [Figure 3] This figure shows an example of a growing space S1 viewed from vertically above. [Figure 4] This figure shows a comparative example of the growth space S1 as viewed from vertically above. [Figure 5] This figure shows an example of the first rotation speed table. [Figure 6] This figure shows an example of a second rotation speed table. [Figure 7] This figure shows an example of a third rotation speed table. [Figure 8] This figure shows an example of a fourth rotation speed table. [Figure 9] This figure shows an example of a fifth rotation speed table. [Figure 10] This figure shows an example of the 6th rotation speed table. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. The various features shown in the embodiments below can be combined with each other.

[0010] <Embodiment> Figure 1 shows an example of the overall configuration of crop cultivation system 1. In Figure 1, the three-dimensional coordinate system is indicated by arrows representing the X, Y, and Z axes, respectively. Hereafter, the X-axis, Y-axis, and Z-axis will be referred to as the left-right direction, the depth direction, and the up-down direction, respectively. Crop cultivation system 1 is a system for cultivating crops while adjusting the environment in a space isolated from the external space S4. Crop cultivation system 1 comprises a pipe house 10 and an air conditioning system 20.

[0011] The pipe house 10 is a structure that forms a growing space S1 for cultivating crops. The growing space S1 has a shape in which the depth direction is longer than the left-right direction. Crops are grown in rows along the depth direction in the growing space S1. The pipe house 10 has pipes that form the framework and a transparent covering that covers the framework. The pipes are made of strong materials such as steel, and the covering is made of a transparent material such as vinyl.

[0012] The pipe house 10 forms an air-conditioned space S2 in addition to the growing space S1. The air-conditioned space S2 is adjacent to the end of the growing space S1 in the depth direction and has a partition 11 between it and the growing space S1. The growing space S1 and the air-conditioned space S2 are connected in such a way that air circulates between them. The air conditioning system 20 is a system that supplies regulated air to crops while circulating air between the growing space S1 and the air-conditioned space S2. Regulated air is, for example, air whose temperature, humidity, or carbon dioxide concentration has been adjusted to promote crop growth, and will be referred to as "regulated air" below.

[0013] The air conditioning system 20 comprises an air conditioner 21, a gas cylinder 22, a blower fan 23, a supply duct 24, multiple return duct fans 25, a return duct 26, a first intake fan 27, a second intake fan 28, a bypass duct 29, a control unit 30, and a differential pressure gauge 31. The air conditioner 21 has an outdoor unit (not shown) and supplies air with adjusted temperature, humidity, and airflow. The gas cylinder 22 is a container filled with liquefied carbon dioxide gas, and releases carbon dioxide when the valve is opened. The air supplied by the air conditioner 21 is mixed with the carbon dioxide released by the gas cylinder 22, and air containing a large amount of carbon dioxide is supplied to the blower fan 23 as regulated air.

[0014] The blower fan 23 rotates to generate an airflow that sends the conditioned air supplied from the air conditioner 21 and the gas cylinder 22 into the supply duct 24. The supply duct 24 is a long, slender cylindrical member for transporting gas and is installed along the depth direction. The supply duct 24 has openings at regular intervals, and the conditioned air that is supplied is released from these openings. The movement path of the conditioned air released from the supply duct 24 will be explained with reference to Figure 2.

[0015] Figure 2 shows an example of the crop cultivation system 1 as viewed in the depth direction. The supply duct 24 is installed so as to be in contact with waterproof vinyl laid on the ground. Note that the waterproof vinyl is not essential, and the supply duct 24 may be installed directly on the ground. On the other hand, the return duct fan 25 is installed at a position higher than the height of the crop, and the fan rotates to generate an airflow toward the inside of the return duct 26. The height of the crop here refers to the height when the crop has grown to its tallest. It is expected that an airflow will be generated from the supply duct 24 toward the return duct fan 25 by the airflow of regulated air released from the supply duct 24 and the airflow generated by the return duct fan 25. Figure 2 shows a typical movement path R1 of this airflow.

[0016] The movement path R1 is a path from the supply duct 24 towards the return duct fan 25. The supply duct 24 and the return duct fan 25 are arranged such that the movement path R1 passes near the center of the crop. By arranging the supply duct 24 and the return duct fan 25 in this way, the conditioned air discharged from the supply duct 24 can be moved so as to touch as wide a range as possible of the surface of the crop.

[0017] Since the conditioned air contains more carbon dioxide than normal air, it promotes photosynthesis compared to the case where normal air is absorbed. When the conditioned air causes an effect of promoting the growth of the crop, its state changes. For example, in the case of the above-mentioned conditioned air, the crop that has carried out photosynthesis releases oxygen, causing a change from a state rich in carbon dioxide to a state rich in oxygen and depleted in carbon dioxide. The air whose state has changed in this way is hereinafter referred to as "changed air". Note that the changed air may also have changed in temperature, humidity, etc.

[0018] The return duct 26 is an elongated cylindrical member for carrying gas. The changed air sucked into the interior of the return duct 26 moves through the interior of the return duct 26 to the air-conditioned space S2. The changed air that has moved to the air-conditioned space S2 is adjusted again by the air conditioner 21 and the gas cylinder 22, becomes conditioned air, and is supplied from the supply duct 24 to the cultivation space S1. In this way, the air conditioner 21, the blower fan 23, and the return duct fan 25 cooperate to circulate the air inside the cultivation space S1 and the air-conditioned space S2.

[0019] The pipe house 10 is provided with a first intake fan 27. The first intake fan 27 rotates the fan to generate an air flow that takes outside air from the external space S4 into the air-conditioned space S2. The first intake fan 27 operates, for example, when the temperature of the air-conditioned space S2 becomes too high to take in outside air for cooling.

[0020] Furthermore, since the covering of the pipe house 10 is made of a soft material such as vinyl, a pressure difference between the growing space S1 and the air-conditioned space S2 can cause damage. The differential pressure gauge 31 is a sensor that measures the pressure difference between the growing space S1 and the air-conditioned space S2. The first intake fan 27 operates, for example, to reduce the pressure difference when the pressure difference measured by the differential pressure gauge 31 becomes too large by taking in outside air.

[0021] The light-adjusting screen 32 is a screen that has the function of adjusting the amount of sunlight that reaches the crops. The light-adjusting screen 32 is installed vertically above the return duct 26 and forms the vertical upper boundary of the growing space S1. An upper space S3 is formed vertically above the light-adjusting screen 32. The light-adjusting screen 32 plays a role in suppressing the exchange of air between the growing space S1 and the upper space S3. Therefore, air circulation in the growing space S1 and air circulation in the upper space S3 are carried out separately.

[0022] The second intake fan 28 rotates to generate an airflow that sends outside air into the bypass duct 29. The bypass duct 29 is a long, slender cylindrical component for transporting gas, connecting the external space and the upper space S3. Therefore, when the second intake fan 28 operates, outside air is sent from the external space S4 into the upper space S3.

[0023] While the growing space S1 can suppress temperature increases by reducing the amount of light using the dimming screen 32, the upper space S3 cannot adjust the amount of light, so its temperature tends to rise more easily than that of the growing space S1. Therefore, the upper space S3 is designed to take in outside air directly from the bypass duct 29, thereby suppressing temperature increases without affecting the circulation of regulated air.

[0024] The pipe house 10 is equipped with an exhaust window 12 in the roof section that is vertically upward. The exhaust window 12 is a pressure-driven exhaust window that passively opens and exhausts air, for example, when the air pressure inside the pipe house 10 rises. The air taken in by the second intake fan 28 is exhausted through the exhaust window 12 to suppress an excessive rise in air pressure in the upper space S3. Also, when the first intake fan 27 takes in outside air, the air pressure in the air-conditioned space S2 and the growing space S1 rises accordingly, so the air taken in is exhausted through the exhaust window 12 to suppress an excessive rise in air pressure in the air-conditioned space S2 and the growing space S1.

[0025] The air conditioner 21 and gas cylinder 22 described above are examples of an air conditioning unit that delivers conditioned air. The supply duct 24 is an example of a first ventilation pipe installed at a position lower than the height of the crops in the growing space S1 where the crops are grown. The return duct 26 is an example of a second ventilation pipe installed at a position higher than the height of the crops in the growing space S1. The return duct 26 is equipped with a return duct fan 25. The return duct fan 25 is an example of a blower that sends air from the growing space S1 into the return duct 26.

[0026] The air conditioning system 20 comprises an air conditioner 21 and a gas cylinder 22 (an example of an air conditioning unit), a supply duct 24 (an example of a first ventilation pipe), a return duct 26 (an example of a second ventilation pipe), and a return duct fan 25 (an example of a blower). The air conditioner 21 and gas cylinder 22 are installed in an air-conditioned space S2, which has a partition 11 between it and the growth space S1, and supply conditioned air into the supply duct 24. The supply duct 24 discharges the supplied conditioned air back into the growth space S1. The return duct fan 25 draws air from the growth space S1 into the return duct 26, and the return duct 26 discharges the air drawn in by the return duct fan 25 back into the air-conditioned space S2.

[0027] Because the growing space S1 is long in the depth direction, without the return duct 26, the air discharged from the supply duct 24 does not easily return to the air-conditioned space S2. Therefore, the further away the space is from the air-conditioned space S2, the more likely the altered air discharged from the crops is to linger above the crops, mixing with the conditioned air and being drawn into the crops. By providing the return duct fan 25 and the return duct 26, the altered air is less likely to linger compared to when these are not provided, and the conditioned air can be supplied to the crops more efficiently.

[0028] Furthermore, the growth space S1 has a shape where the long and short directions are determined when viewed from vertically above. Figure 3 shows an example of a growing space S1 viewed from vertically above. In the crop growing system 1 shown in Figure 3, the growing space S1 has a rectangular shape with the depth direction as the longitudinal direction and the left-right direction as the short direction. The air conditioning space S2 is adjacent to one end of the growing space S1 in the longitudinal direction. A supply duct 24 (an example of a first ventilation pipe) and a return duct 26 (an example of a second ventilation pipe) are provided from one end of the growing space S1 along the longitudinal direction to a position further from the other end than the center C1 of the growing space S1.

[0029] The supply duct 24 consists of two ducts located at the left and right ends, each having openings 41, 42, 43, ..., 47, and 48 (referred to as "opening 40" unless otherwise distinguished). The return duct 26 consists of one duct located in the center in the left and right direction, and has return duct fans 25-1, 25-2, 25-3, ..., 25-7, and 25-8 (referred to as "return duct fans 25" unless otherwise distinguished).

[0030] Each of the multiple openings 40 is provided with a return duct fan 25 corresponding to a position where the distance in the depth direction from the air-conditioned space S2 is the same. For example, opening 41 is provided with a return duct fan 25-1, and opening 48 is provided with a return duct fan 25-8. The conditioned air discharged from each opening 40 is partially absorbed by the crops to become modified air, which is then sent to the return duct 26 by the corresponding return duct fan 25. In Figure 3, the path of the circulating air is shown by a dashed line.

[0031] Here, we will describe a comparative example in which the return duct 26 is shorter. Figure 4 shows a comparative example of the growing space S1 as viewed from vertically above. In the crop growing system 1a shown in Figure 4, the supply duct 24 (an example of the first ventilation pipe) is provided along the longitudinal direction from one end of the growing space S1 to a position further from the center C1 of the growing space S1 than the other end, but the return duct 26 (an example of the second ventilation pipe) is provided along the longitudinal direction from one end of the growing space S1 to a position closer to the center C1 of the growing space S1 than the other end.

[0032] In the example shown in Figure 4, air is circulated from opening 41 to opening 44 through the corresponding return duct fans 25-1 to 25-4, respectively. On the other hand, from opening 45 to opening 48, there is no corresponding return duct fan 25, so the conditioned air discharged and the air discharged by the crops, including the altered air, accumulates in the stagnation space D1 shown by the dashed line. In the crop cultivation system 1, as shown in Figure 3, the stagnation space D1 does not occur, so the conditioned air can be circulated over a wider area of ​​the cultivation space S1 compared to when the return duct 26 is short.

[0033] The crop cultivation system 1 comprises the air conditioning system 20 described above and a pipe house 10. The pipe house 10 is an example of a structure that forms the cultivation space S1 and the air-conditioned space S2. As shown in Figure 1, the crop cultivation system 1 also comprises a first blower, a light-adjusting member, an exhaust port, and a second blower. The first intake fan 27 is an example of a first blower that takes in outside air into the air-conditioned space S2. The light-adjusting screen 32 is an example of a light-adjusting member that is installed vertically above the crops to adjust the amount of light passing through.

[0034] The exhaust window 12 is an example of an exhaust port that discharges air from the upper space S3 vertically above the dimming screen 32. The second intake fan 28 is an example of a second blower that draws outside air into the upper space S3. The second intake fan 28 (an example of a second blower) and the exhaust window 12 (an example of an exhaust port) exchange the air in the upper space S3. Meanwhile, the supply duct 24 (an example of a first ventilation pipe) and the return duct 26 (an example of a second ventilation pipe) circulate the air in the growing space S1.

[0035] In this configuration, air can be exchanged separately above and below the light-adjusting member. For example, since the light-adjusting screen 32 blocks sunlight, the temperature rise of the air in the growing space S1 is suppressed, but the air in the upper space S3 is more prone to temperature rise than the air in the growing space S1 because the only thing blocking sunlight is a transparent film. Therefore, by exchanging the air separately as described above, it is possible to suppress the rise in temperature in the growing space S1 more effectively than when the air is exchanged together.

[0036] The control unit 30 is a computer that has a processor such as a Central Processing Unit (CPU) and a storage unit such as a storage device like a Solid State Drive (SSD) or a memory like a Random Access Memory (RAM). By reading a predetermined program stored in the storage unit, it realizes various functions related to the crop cultivation system 1. That is, the information processing by software stored in the storage unit is specifically realized by the control unit 30, which is an example of hardware, and can be executed as each functional unit included in the control unit 30. Note that the control unit 30 is not limited to being single, and may be implemented to have a plurality of control units 30 for each function, or a combination thereof may also be possible.

[0037] As shown in FIG. 3, a plurality of return duct fans 25 (an example of a blower) are provided in the return duct 26 (an example of the second ventilation duct). The control unit 30 functions as an example of a first control unit that controls the rotational speed of the plurality of return duct fans 25 according to the distance from one end of the cultivation space S1. Here, the one end mentioned refers to the end of the cultivation space S1 where the air-conditioned space S2 is adjacent, and hereinafter it will be referred to as the "end on the air-conditioned space S2 side". The control unit 30 performs control using a first rotational speed table in which the distance from the end on the air-conditioned space S2 side and the rotational speed are associated.

[0038] FIG. 5 is a diagram showing an example of the first rotational speed table. In the first rotational speed table TB1 shown in FIG. 5, for the return duct fans 25-1, 25-2, 25-3, ···, 25-7 and 25-8, distances "D1", "D2", "D3", ···, "D7" and "D8" from the end on the air-conditioned space S2 side (D1 < D2 < D3 < ··· < D7 < D8) and rotational speeds "RS1", "RS2", "RS3", ···, "RS7" and "RS8" are associated. Each rotational speed has, for example, a magnitude relationship of RS1 < RS2 < RS3 < ··· < RS7 < RS8.

[0039] The longer the distance from the end on the air-conditioned space S2 side, the longer the distance for returning the changed air to the air-conditioned space S2 through the return duct 26. Therefore, by increasing the rotational speed of the return duct fan 25, the amount of air circulated is made constant regardless of the distance from the end on the air-conditioned space S2 side compared to the case where the rotational speed is uniform. As a result, compared to the case where the rotational speed is uniform, the changed air is less likely to stay regardless of the distance from the end on the air-conditioned space S2 side, and the adjusted air concentration in the cultivation space can be made more uniform.

[0040] Further, the control unit 30 functions as an example of a second control unit that controls the rotational speeds of the plurality of return duct fans 25 according to the rotational speed of the first intake fan 27 (an example of the first blower). The control unit 30 performs control using a second rotational speed table in which the rotational speed of the first intake fan 27 and the reference rotational speeds of the respective return duct fans 25 are associated. The reference rotational speed is, for example, the rotational speed of the return duct fan 25-1. The rotational speeds of the other return duct fans 25 are assumed to be the rotational speed obtained by adding a predetermined rotational speed to the reference rotational speed or the rotational speed obtained by multiplying the reference rotational speed by a predetermined count.

[0041] FIG. 6 is a diagram showing an example of the second rotational speed table. In the second rotational speed table TB2 shown in FIG. 6, the rotational speeds (RS11 < RS12 < RS13 < RS14) of the first intake fan 27, denoted as "RS11", "RS12", "RS13", and "RS14", are associated with the reference rotational speeds of the return duct fans 25, denoted as "RS21", "RS22", "RS23", and "RS24". Each reference rotational speed has, for example, a magnitude relationship such that RS21 > RS22 > RS23 > RS24.

[0042] As the rotational speed of the first intake fan 27 increases, the air pressure in the air-conditioned space S2 rises, so the air pressure difference between the cultivation space S1 and the air-conditioned space S2 becomes larger. Therefore, as the rotational speed of the first intake fan 27 increases, the reference rotational speed is decreased to reduce the air returning from the cultivation space S1, thereby reducing the air pressure difference between the cultivation space S1 and the air-conditioned space S2 compared to the case where the reference rotational speed is uniform, and suppressing damage to the pipe house 10 due to this air pressure difference.

[0043] Further, the control unit 30 functions as an example of a third control unit that controls the rotational speeds of the plurality of return duct fans 25 according to the rotational speed of the second intake fan 28 (an example of a second blower). The control unit 30 performs control using a third rotational speed table in which the rotational speed of the second intake fan 28 and the reference rotational speeds of the respective return duct fans 25 are associated with each other. The reference rotational speed and the rotational speeds of the other return duct fans 25 are the same as those described in the second rotational speed table.

[0044] FIG. 7 is a diagram showing an example of the third rotational speed table. The third rotational speed table TB3 shown in FIG. 7 associates the rotational speeds (RS31 < RS32 < RS, 33 < RS34) of the second intake fan 28, designated as "RS31", "RS32", "RS33", and "RS34", with the reference rotational speeds of the return duct fans 25, designated as "RS41", "RS42", "RS43", and "RS44". Each reference rotational speed has, for example, a magnitude relationship of RS41 > RS42 > RS43 > RS44.

[0045] As the rotation speed of the second intake fan 28 increases, the air pressure in the upper space S3 rises, and the pressure difference between the growth space S1 and the upper space S3 increases. Here, the dimming screen 32 does not completely separate the growth space S1 and the upper space S3, and some air circulates between them. Therefore, when this pressure difference increases, the warmed air from the upper space S3 is more likely to descend into the growth space S1. So, as the rotation speed of the second intake fan 28 increases, the reference rotation speed is reduced, and the amount of air returning from the growth space S1 is reduced. Compared to when the reference rotation speed is constant, the pressure difference between the growth space S1 and the upper space S3 is reduced, and this pressure difference can suppress the air from the upper space S3 from descending into the growth space S1.

[0046] Furthermore, the control unit 30 functions as an example of a fourth control unit that controls the rotational speed of multiple return duct fans 25 according to the pressure difference between the growth space S1 and the air-conditioned space S2. The control unit 30 performs control using a fourth rotational speed table that associates the pressure difference between the growth space S1 and the air-conditioned space S2 with the reference rotational speed of each return duct fan 25. The reference rotational speed and the rotational speeds of the other return duct fans 25 are the same as those described in the second rotational speed table.

[0047] Figure 8 shows an example of the fourth rotation speed table. The fourth rotation speed table TB4 shown in Figure 8 associates the pressure difference between the growth space S1 and the air-conditioned space S2 (-E51>-E52>-E53>-E54>0>+E55>+E56>+E57>+E58), which are "-E51", "-E52", "-E53", "-E54", "+E55", "+E56", "+E57", and "+E58", with the reference rotation speeds of the return duct fan 25, which are "RS51", "RS52", "RS53", "RS54", "RS55", "RS56", "RS57", and "RS58".

[0048] When the pressure difference is negative, it means that the pressure in the cultivation space S1 is lower, and when the pressure difference is positive, it means that the pressure in the cultivation space S1 is higher. In that case, each reference rotation speed has, for example, a magnitude relationship of RS51 < RS52 < RS53 < RS54 < RS55 < RS56 < RS57 < RS58. The control unit 30 controls based on the pressure difference between the cultivation space S1 and the air-conditioned space S2 measured by the differential pressure gauge 31, increasing the reference rotation speed as the pressure in the cultivation space S1 is higher compared to the pressure in the air-conditioned space S2, so as to increase the amount of air returning from the cultivation space S1 to the air-conditioned space S2.

[0049] Thereby, as the pressure in the cultivation space S1 is higher compared to the pressure in the air-conditioned space S2, air is sucked up from the cultivation space S1 to lower the pressure while air is sent into the air-conditioned space S2 to increase the pressure, making the pressure difference between the cultivation space S1 and the air-conditioned space S2 smaller compared to the case where the reference rotation speed is uniform. In such a manner, compared to the case where the control described in FIG. 8 is not performed, it is possible to suppress the pipe house 10 (especially the partition 11 part) from being damaged due to the pressure difference between the cultivation space S1 and the air-conditioned space S2.

[0050] Also, the control unit 30 functions as an example of a fifth control unit that controls the rotation speeds of the plurality of return duct fans 25 according to the pressure difference between the air-conditioned space S2 and the external space S4. The control unit 30 performs control using a fifth rotation speed table that associates the pressure difference between the air-conditioned space S2 and the external space S4 with the reference rotation speeds of each return duct fan 25. The reference rotation speed and the rotation speeds of the other return duct fans 25 are the same as those described in the second rotation speed table.

[0051] Figure 9 shows an example of the fifth rotation speed table. The fifth rotation speed table TB5 shown in Figure 9 associates the pressure difference between the air-conditioned space S2 and the external space S4 (-E61>-E62>-E63>-E64>0>+E65>+E66>+E67>+E68), which are "-E61", "-E62", "-E63", "-E64", "+E65", "+E66", "+E67", and "+E68", with the reference rotation speeds of the return duct fan 25, which are "RS61", "RS62", "RS63", "RS64", "RS65", "RS66", "RS67", and "RS68".

[0052] A negative pressure difference indicates that the air-conditioned space S2 has lower pressure, and a positive pressure difference indicates that the air-conditioned space S2 has higher pressure. In this case, the reference rotation speeds have a relative order of magnitude, for example, RS61 > RS62 > RS63 > RS64 > RS65 > RS66 > RS67 > RS68. In this way, the control unit 30 controls the system to reduce the reference rotation speed as the air pressure in the air-conditioned space S2 is higher than the air pressure in the external space S4, thereby reducing the amount of air returning from the growth space S1 to the air-conditioned space S2.

[0053] As a result, the higher the air pressure in the air-conditioned space S2 is compared to the air pressure in the external space S4, the less air is supplied to the air-conditioned space S2 to lower its air pressure, and the smaller the pressure difference between the air-conditioned space S2 and the external space S4 is compared to when the reference rotation speed is uniform. With this configuration, damage to the pipe house 10 (especially the part covering the air-conditioned space S2) due to the pressure difference between the air-conditioned space S2 and the external space S4 can be suppressed compared to when the control described in Figure 9 is not performed.

[0054] Furthermore, the control unit 30 functions as an example of a sixth control unit that controls the rotational speed of multiple return duct fans 25 according to the pressure difference between the growth space S1 and the external space S4. The control unit 30 performs control using a sixth rotational speed table that associates the pressure difference between the growth space S1 and the external space S4 with the reference rotational speed of each return duct fan 25. The reference rotational speed and the rotational speeds of the other return duct fans 25 are the same as those described in the second rotational speed table.

[0055] FIG. 10 is a diagram showing an example of the sixth rotation speed table. The sixth rotation speed table TB6 shown in FIG. 10 associates the pressure differences (-E71 > -E72 > -E73 > -E74 > 0 > +E75 > +E76 > +E77 > +E78) between the cultivation space S1 and the external space S4, namely, "-E71", "-E72", "-E73", "-E74", "+E75", "+E76", "+E77", and "+E78", with the reference rotation speeds of the return duct fan 25, namely, "RS71", "RS72", "RS73", "RS74", "RS75", "RS76", "RS77", and "RS78".

[0056] It is assumed that when the pressure difference is negative, the pressure in the cultivation space S1 is lower, and when the pressure difference is positive, the pressure in the cultivation space S1 is higher. In that case, the reference rotation speeds, for example, have a magnitude relationship of RS71 < RS72 < RS73 < RS74 < RS75 < RS76 < RS77 < RS78. Thus, the control unit 30 controls to increase the reference rotation speed as the pressure in the cultivation space S1 is higher than the pressure in the external space S4, so as to increase the air sucked up from the cultivation space S1.

[0057] Thereby, as the pressure in the cultivation space S1 is higher than the pressure in the external space S4, more air is sucked up from the cultivation space S1 to lower the pressure in the cultivation space S1, and the pressure difference between the cultivation space S1 and the external space S4 becomes smaller compared to the case where the reference rotation speed is uniform. In such a manner, it is possible to suppress the damage of the pipe house 10 (especially the portion covering the cultivation space S1) due to the pressure difference between the cultivation space S1 and the external space S4 compared to the case where the control described in FIG. 10 is not performed.

[0058] <Configuration Variations> In this embodiment, the structure forming the growing space S1 and the air-conditioned space S2 was a pipe house 10, but it is not limited to this. For example, the structure may be a steel-frame house made of steel frames instead of pipes. Alternatively, the growing space S1 and the air-conditioned space S2 may be formed using a concrete building as the structure, similar to a so-called plant factory. In any of these structures, providing a return duct 26 makes it less likely for the changed air to stagnate, and allows for the efficient supply of conditioned air to the crops.

[0059] Furthermore, while the shape of the growth space S1 was rectangular when viewed from vertically above in the embodiment, it is not limited to this. The shape of the growth space S1 may be an L-shape that is bent in the middle when viewed from vertically above, or it may be a long, narrow ellipse, or it may form an arc. In any case, if the growth space S1 has a shape that has a defined longitudinal and transverse direction when viewed from vertically above, a return duct 26 can be provided along the longitudinal direction to a position further away from the end of the growth space S1 on the air conditioning space S2 side than the center of the growth space S1. This allows the conditioned air to be circulated over a wider area of ​​the growth space S1 compared to when the return duct 26 is short.

[0060] Furthermore, the return duct 26 does not need to be installed along the longitudinal direction, but only from the end of the growing space S1 closer to the air-conditioned space S2 side than the center. Even in this case, within the range where the return duct 26 is installed, the conditioned air is less likely to stagnate, and the conditioned air can be efficiently supplied to the crops. In short, the return duct 26 can provide a certain effect simply by being installed. Moreover, it is desirable for the return duct 26 to be installed over a wide range along the longitudinal direction, and the wider the range of the return duct 26 is installed—10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more—the greater the effect of being able to circulate the conditioned air over a wider range of the growing space S1.

[0061] Furthermore, in the embodiment, the air conditioning system 20 included two supply ducts 24 and one return duct 26, but it is not limited to this. The air conditioning system 20 may include one supply duct 24, three or more supply ducts 24, or two or more return ducts 26. In short, the air conditioning system 20 only needs to include one or more supply ducts 24 and one or more return ducts 26.

[0062] Furthermore, although the embodiment provided multiple return duct fans 25 in the return duct 26, only one return duct fan 25 may be provided. Even in that case, the conditioned air is less likely to stagnate near the return duct fan 25, and the conditioned air can be supplied to the crops more efficiently than when neither the return duct fan 25 nor the return duct 26 is provided. Also, although the embodiment provided multiple openings 40 in the supply duct 24, only one opening 40 may be provided. Even in that case, the conditioned air will be supplied to the growing space S1. In short, it is sufficient to provide one or more return duct fans 25 and one or more openings 40.

[0063] <Note> Furthermore, they may be provided in the following embodiments.

[0064] (1) An air conditioning system comprising an air conditioning unit that delivers conditioned air, a first ventilation pipe, a second ventilation pipe, and a blower provided in the second ventilation pipe, wherein the first ventilation pipe is provided in a growing space for growing crops at a position lower than the height of the crops, the second ventilation pipe is provided in the growing space at a position higher than the height of the crops, the air conditioning unit is installed in an air conditioning space separated from the growing space by a partition, delivers the conditioned air into the first ventilation pipe, the first ventilation pipe discharges the delivered conditioned air into the growing space, the blower sends air from the growing space into the second ventilation pipe, and the second ventilation pipe discharges the air sent in by the blower into the air conditioning space.

[0065] In this configuration, regulated air can be efficiently supplied to crops.

[0066] (2) An air conditioning system as described in (1) above, wherein the growing space has a shape in which the longitudinal direction and the short direction are determined when viewed from vertically above, the air conditioning space is adjacent to one end of the growing space in the longitudinal direction, and the first ventilation pipe and the second ventilation pipe are provided from the one end along the longitudinal direction to a position further from the one end than the center of the growing space.

[0067] This configuration allows for the circulation of conditioned air over a wider area of ​​the growing space.

[0068] (3) An air conditioning system as described in (2) above, wherein the second ventilation pipe is provided with a plurality of blowers, and the air conditioning system includes a first control unit that controls the rotational speed of the plurality of blowers according to the distance from one end.

[0069] This configuration allows for a more uniform concentration of the controlled air in the growing space.

[0070] (4) A crop cultivation system comprising an air conditioning system as described in any one of (1) to (3) above, and the cultivation space and a structure forming the air conditioning space.

[0071] In this configuration, regulated air can be efficiently supplied to crops.

[0072] (5) A crop cultivation system as described in (4) above, comprising: a first blower for taking in outside air into the air-conditioned space; a light-adjusting member provided vertically above the crop for adjusting the amount of light passing through; an exhaust port for discharging air from the upper space vertically above the light-adjusting member; and a second blower for taking in outside air into the upper space, wherein the second blower and the exhaust port replace the air in the upper space, and the first and second ventilation pipes circulate the air in the cultivation space.

[0073] In this configuration, air can be exchanged separately above and below the dimming element.

[0074] (6) A crop cultivation system as described in (5) above, wherein the second ventilation pipe is provided with a plurality of blowers, and the system includes a second control unit that controls the rotational speed of the plurality of blowers according to the rotational speed of the first blower or the second blower.

[0075] According to this configuration, the pressure difference between the growing space and the air-conditioned space can be reduced.

[0076] (7) A crop cultivation system according to (5) or (6) above, wherein the second ventilation pipe is provided with a plurality of blowers, and a third control unit is provided that controls the rotational speed of the plurality of blowers according to the rotational speed of the second blowers.

[0077] According to this configuration, the pressure difference between the growing space and the upper space can be reduced.

[0078] (8) A crop cultivation system according to any one of (5) to (7) above, comprising a fourth control unit that controls the rotational speed of the blower according to the pressure difference between the cultivation space and the air-conditioned space.

[0079] According to this configuration, the pressure difference between the growing space and the upper space can be reduced.

[0080] (9) A crop cultivation system according to any one of (5) to (8) above, comprising a fifth control unit that controls the rotational speed of the blower according to the pressure difference between the air-conditioned space and the outside space.

[0081] According to this configuration, the pressure difference between the air-conditioned space and the outside air can be reduced.

[0082] (10) A crop cultivation system according to any one of (5) to (9) above, comprising a sixth control unit that controls the rotational speed of the blower according to the pressure difference between the cultivation space and the outside space.

[0083] According to this configuration, the pressure difference between the growing space and the outside air can be reduced. Of course, this is not always the case. Furthermore, the embodiments and modifications described above may be implemented in any combination.

[0084] Finally, various embodiments of the present invention have been described, but these are presented as examples only and are not intended to limit the scope of the invention. Novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0085] 1: Crop cultivation system 1a: Crop cultivation system 10: Pipe House 11: Divider 12: Exhaust vent 20: Air conditioning system 21:Air conditioner 22: Gas cylinder 23: Blower fan 24: Supply duct 25: Fan for return duct 26: Return duct 27: First intake fan 28: Second intake fan 29: Bypass duct 30: Control Unit 31: Differential pressure gauge 32: Dimmable screen 40: Opening

Claims

1. It is an air conditioning system, The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. Multiple blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the multiple blowers into the air-conditioned space. The aforementioned growing space has a shape in which the longitudinal and transverse directions are determined when viewed from vertically above. The aforementioned air-conditioned space is adjacent to one end of the growth space in the longitudinal direction, The first ventilation pipe and the second ventilation pipe are provided from one end along the longitudinal direction to a position further from the one end than the center of the growing space, The system includes a first control unit that controls the rotational speed of the plurality of blowers according to the distance from one end. Air conditioning system.

2. The air conditioning system according to claim 1, Structures forming the aforementioned growing space and the aforementioned air-conditioned space Equipped with Crop cultivation system.

3. A crop cultivation system, Equipped with an air conditioning system and a structure, The aforementioned air conditioning system is The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. The plurality of blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the plurality of blowers into the air-conditioned space. The aforementioned structure forms the growing space and the air-conditioned space. A first blower that takes in outside air into the aforementioned air-conditioned space, A light-adjusting member is provided vertically above the crop to adjust the amount of light passing through, An exhaust port for discharging air from the space above the dimming member, The upper space is equipped with a second blower that takes in outside air, The second blower and the exhaust port replace the air in the upper space. The first ventilation pipe and the second ventilation pipe circulate the air in the growing space. The system includes a second control unit that controls the rotational speed of the plurality of blowers according to the rotational speed of the first blower or the second blower. Crop cultivation system.

4. A crop cultivation system, Equipped with an air conditioning system and a structure, The aforementioned air conditioning system is The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. The plurality of blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the plurality of blowers into the air-conditioned space. The aforementioned structure forms the growing space and the air-conditioned space. A first blower that takes in outside air into the aforementioned air-conditioned space, A light-adjusting member is provided vertically above the crop to adjust the amount of light passing through, An exhaust port for discharging air from the space above the dimming member, The upper space is equipped with a second blower that takes in outside air, The second blower and the exhaust port replace the air in the upper space. The first ventilation pipe and the second ventilation pipe circulate the air in the growing space. The system includes a third control unit that controls the rotational speed of the plurality of blowers in accordance with the rotational speed of the second blower. Crop cultivation system.

5. A crop cultivation system, Equipped with an air conditioning system and a structure, The aforementioned air conditioning system is The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. The plurality of blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the plurality of blowers into the air-conditioned space. The aforementioned structure forms the growing space and the air-conditioned space. A first blower that takes in outside air into the aforementioned air-conditioned space, A light-adjusting member is provided vertically above the crop to adjust the amount of light passing through, An exhaust port for discharging air from the space above the dimming member, The upper space is equipped with a second blower that takes in outside air, The second blower and the exhaust port replace the air in the upper space. The first ventilation pipe and the second ventilation pipe circulate the air in the growing space. The system includes a fourth control unit that controls the rotational speed of the plurality of blowers according to the pressure difference between the growing space and the air-conditioned space. Crop cultivation system.

6. A crop cultivation system, Equipped with an air conditioning system and a structure, The aforementioned air conditioning system is The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. The plurality of blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the plurality of blowers into the air-conditioned space. The aforementioned structure forms the growing space and the air-conditioned space. A first blower that takes in outside air into the aforementioned air-conditioned space, A light-adjusting member is provided vertically above the crop to adjust the amount of light passing through, An exhaust port for discharging air from the space above the dimming member, The upper space is equipped with a second blower that takes in outside air, The second blower and the exhaust port replace the air in the upper space. The first ventilation pipe and the second ventilation pipe circulate the air in the growing space. The system includes a fifth control unit that controls the rotational speed of the plurality of blowers according to the pressure difference between the air-conditioned space and the outside space. Crop cultivation system.

7. A crop cultivation system, Equipped with an air conditioning system and a structure, The aforementioned air conditioning system is The system comprises an air conditioning unit that delivers regulated air, a first ventilation pipe, a second ventilation pipe, and a plurality of blowers provided in the second ventilation pipe. The first ventilation pipe is installed in the growing space for growing crops at a position lower than the height of the crops. The second ventilation pipe is provided in the growing space at a position higher than the height of the crop. The air conditioning unit is installed in an air-conditioned space separated from the growing space by a partition, and sends the conditioned air into the first ventilation pipe. The first ventilation pipe discharges the adjusted air that has been sent out into the growth space. The plurality of blowers send air from the growing space into the second ventilation pipe, The second ventilation pipe discharges the air supplied by the plurality of blowers into the air-conditioned space. The aforementioned structure forms the growing space and the air-conditioned space. A first blower that takes in outside air into the aforementioned air-conditioned space, A light-adjusting member is provided vertically above the crop to adjust the amount of light passing through, An exhaust port for discharging air from the space above the dimming member, The upper space is equipped with a second blower that takes in outside air, The second blower and the exhaust port replace the air in the upper space. The first ventilation pipe and the second ventilation pipe circulate the air in the growing space. The system includes a sixth control unit that controls the rotational speed of the plurality of blowers according to the pressure difference between the growing space and the outside space. Crop cultivation system.

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