JP2024145043A - Plant growing device and plant growing method - Google Patents

Abstract

To provide a plant growing device and a plant growing method that can reduce the amount of heat dissipated from a light source into a cultivation space in which plants are cultivated.SOLUTION: A plant growing device 100 grows plants using artificial light. The plant growing device includes: light sources 10 that irradiate plants 200 with artificial light having light-emitting elements (LEDs) 12 and a support substrate 11 on which the light-emitting elements 12 are arranged; a liquid fertilizer storage section 31 having a storage container that stores a liquid fertilizer 32 to be supplied to the plant 200; and a heat dissipation section that is in contact with the support substrate 11 and the storage container and dissipates heat from the light source 10 to the liquid fertilizer 32.SELECTED DRAWING: Figure 1

Description

The present invention relates to a plant growing device and a plant growing method that grow plants using artificial light.

In recent years, the world population has been increasing, and it is predicted that the world population will reach 9 billion by 2050. Therefore, there are concerns about food shortages in the future.
One way to deal with such food shortages is to increase agricultural production and ensure stable harvests throughout the year. In particular, securing plant-based proteins as an alternative to animal proteins is an important issue.

As a measure to increase agricultural production and achieve stable harvests, greenhouse horticulture and plant factories are being considered. Furthermore, in plant factories, the adoption of vertical farming, which allows stable production of agricultural products in a relatively small space even if it is not possible to secure a large amount of land as in conventional agriculture, is also being considered.
In a plant factory, it is possible to control various parameters such as the intensity of light for photosynthesis irradiated from an artificial light source to the crops, environmental conditions such as temperature, humidity, carbon dioxide ( _CO2 ) concentration, and wind speed in the plant growth space, and fertilizer components for plant growth, etc. Therefore, crops can be produced year-round, and the productivity of crops can be dramatically increased.
For example, Patent Document 1 discloses a closed plant factory that cultivates plants by irradiating them with artificial light such as LED light without using sunlight.

Patent No. 5330162

However, in the closed-type plant factory described in the above Patent Document 1, the temperature, humidity, and CO2 concentration of the entire room in which the plant cultivation container shelves for growing plants and the lighting shelves for irradiating the plants with _light are arranged are controlled. Therefore, it is necessary to control the air conditioning of the room to provide an environment suitable for the plants while removing heat from the light sources such as LEDs, and running costs are incurred for the air conditioning control.
In addition, in general, in plant factories, air is circulated by flowing horizontally between the shelves of the cultivation racks, but the air supplied from the side of the plants absorbs heat from the light source arranged along the air flow direction, so the air temperature becomes higher the further downstream it goes. This creates a temperature gradient between the upstream and downstream sides, resulting in differences in growth for each plant. The more heat is dissipated from the light source, the more pronounced the temperature gradient becomes.

Therefore, the objective of the present invention is to provide a plant growing device and a plant growing method that can reduce the amount of heat dissipated from a light source into the cultivation space in which the plants are grown.

In order to solve the above problems, one aspect of the plant growing device of the present invention is a plant growing device that grows a plant using artificial light, and is equipped with an artificial light source having a light-emitting element and a support substrate on which the light-emitting element is arranged, which irradiates the plant with the artificial light, a liquid fertilizer storage unit having a storage container for storing liquid fertilizer to be supplied to the plant, and a heat dissipation unit that is in contact with the support substrate and the liquid fertilizer stored in the storage container and dissipates heat from the artificial light source to the liquid fertilizer.
This allows the heat of the light source to be dissipated by using liquid fertilizer, thereby reducing the amount of heat dissipated from the light source to the plant cultivation space, and more appropriately reducing the impact of the heat of the light source on the plant cultivation space.

In the above-mentioned plant growing device, the heat dissipation portion may be an end portion of the support substrate and may be immersed in the liquid fertilizer.
In this case, heat from the light source can be dissipated directly into the liquid fertilizer.

Furthermore, in the above-mentioned plant growing device, the heat dissipation section may be the container with which a part of the support substrate is in contact.
In this case, heat from the light source can be dissipated into the liquid fertilizer through the liquid fertilizer container. Also, since the support substrate does not need to be immersed in the liquid fertilizer, there is no risk of the support substrate being corroded or short-circuited by the liquid fertilizer.

In the above plant growing device, the storage container may be made of metal.
In this case, the container for storing the liquid fertilizer can efficiently transfer heat from the light source to the liquid fertilizer.

In addition, in the above-mentioned plant growing device, the heat dissipation section may be a heat dissipation plate that is disposed within the storage container and is in contact with at least a part of the support substrate and the liquid fertilizer.
In this case, even if the container is made of a material with low thermal conductivity, the heat from the light source can be dissipated to the liquid fertilizer through the heat sink. Also, since the support substrate does not need to be immersed in the liquid fertilizer, there is no risk of the support substrate being corroded or short-circuited by the liquid fertilizer.

Furthermore, the plant growing device may further include a cooling section that cools the liquid fertilizer contained in the liquid fertilizer containing section.
In this case, the liquid fertilizer that has absorbed the heat from the light source can be appropriately cooled, and an increase in the temperature of the liquid fertilizer can be suppressed.

In addition, the above-mentioned plant cultivation device may be provided with an air intake port provided above or below the plant, supplying air to the cultivation space in which the plant is cultivated, and an exhaust port provided above or below the plant, exhausting air from within the cultivation space.
In this case, air can be made to flow vertically (in the direction of plant growth) in the cultivation space. If the plants are densely packed or tall, it is difficult for air to flow horizontally, which can lead to differences in plant growth between the upstream and downstream sides. However, by making the air flow vertical, it is possible to create a uniform air flow within the cultivation space and reduce differences in growth between individual plants.

In the above plant growing device, the air intake port may be provided below the plant, and the air exhaust port may be provided above the plant.
In this case, air can be made to flow from the bottom up within the cultivation space, so that the warm air that rises above the plants can be exhausted without diffusing.

The plant growing device may further include a blower unit configured to blow air and form an air flow in the cultivation space. In the plant growing device, the blower unit may include a fan.
In this case, air can be actively circulated within the cultivation space.

In the above-mentioned plant growing device, the air blowing section may include an air conditioning control section that controls at least one of a temperature, a humidity, an air volume, and a _CO2 concentration in the cultivation space.
In this case, the cultivation space can be adjusted to an environment suitable for the plants.

Furthermore, in the above plant growing device, the artificial light source may be arranged so as to irradiate the artificial light laterally with respect to a growth direction of the plant.
In this case, light can be irradiated from the side of the plant, and an appropriate amount of light can be irradiated not only to the upper part of the plant but also to the leaves located at the lower part of the plant, thereby enabling the plant to grow efficiently.

In the above plant growing device, a length in a vertical direction of a light emitting surface of the artificial light source may be shorter than a length in a direction perpendicular to the vertical direction of the light emitting surface.
In this case, the air can be made to flow in the direction of the short side of the light-emitting surface of the light source, which makes it possible to prevent a large temperature gradient from occurring between the air intake port side and the air exhaust port side, compared to when the air is made to flow horizontally, which is the direction of the long side of the light-emitting surface.

Furthermore, the above-mentioned plant cultivation device further includes a plurality of liquid fertilizer storage sections arranged below the plants and storing liquid fertilizer to be supplied to the plants, and the plurality of liquid fertilizer storage sections are arranged at a distance from each other so as to supply the liquid fertilizer to the plants arranged in a specific direction on a row-by-row basis, and either the air intake port or the exhaust port may be provided between adjacent liquid fertilizer storage sections.
In this way, the liquid fertilizer storage section is divided into a plurality of sections so that liquid fertilizer is supplied to the plants for each row, and therefore, an air inlet or an exhaust outlet can be appropriately provided below the plants, so that air can be appropriately supplied or exhausted from below the plants.

Furthermore, the above-mentioned plant cultivation device may further include a sensor for detecting the temperature of the liquid fertilizer stored in the liquid fertilizer storage section, and a liquid fertilizer control section for controlling the temperature of the liquid fertilizer stored in the liquid fertilizer storage section based on the detection value by the sensor.
In this case, liquid fertilizer can be supplied to the plants at a temperature suitable for plant growth. In addition, since the plant cultivation space and the liquid fertilizer space are separated, temperature control specialized for the liquid fertilizer can be performed.

In addition, the above-mentioned plant cultivation device may further include a housing that forms a closed space surrounding the plant, the housing being optically transparent to the artificial light, and the artificial light source being disposed outside the housing and irradiating the artificial light to the plant through the housing.
In this case, the plant cultivation space and the heat dissipation space of the light source can be separated by the housing, and the plant cultivation space can be configured to be less susceptible to the effects of heat from the light source. Therefore, when creating an environment suitable for plants in the cultivation space, there is no need to control the air conditioning while removing heat from the light source, and environmental control specialized for plants is possible. Therefore, plants can be grown efficiently while keeping costs down.

Furthermore, in the above plant growing device, the housing may surround the plants arranged in a specific direction in rows.
In this case, the environment of the plant cultivation space can be controlled for each row. Also, it is possible to install a light source between each row, so that the photosynthetic efficiency of the plants can be appropriately improved.

Moreover, one aspect of the plant cultivation method according to the present invention is a plant cultivation method for cultivating a plant using artificial light, comprising the steps of irradiating the plant with artificial light from an artificial light source, and bringing a heat dissipation unit into contact with a support substrate on which light-emitting elements of the artificial light source are arranged and with liquid fertilizer to be supplied to the plant, thereby dissipating heat from the artificial light source to the liquid fertilizer.
This allows the heat of the light source to be dissipated by using liquid fertilizer, thereby reducing the amount of heat dissipated from the light source into the space, and more appropriately reducing the impact of the heat from the light source on the plant cultivation space.

The present invention can reduce the amount of heat dissipated from the light source into the cultivation space in which the plants are grown.

FIG. 1 is a schematic diagram showing an example of a schematic configuration of a plant growing device according to an embodiment of the present invention. FIG. 2 is a side view showing a configuration example of an artificial light source. FIG. 2B is a view of the artificial light source in FIG. 2A as viewed in the direction of the arrow A. 1 is a configuration example of an artificial light source equipped with a heat-resistant member. 13 is another example of an artificial light source. FIG. 2 is a side view showing an example of a cultivation space. FIG. 1 is a side view showing an example of conventional cultivation using upward irradiation. FIG. 1 is a top view showing an example of conventional cultivation using side irradiation. FIG. 1 is a side view showing an example of conventional cultivation using side irradiation. FIG. 13 is a diagram showing another example of heat dissipation from a light source using liquid fertilizer. FIG. 13 is a diagram showing another example of heat dissipation from a light source using liquid fertilizer. FIG. 4 is a diagram showing an example of the configuration of a liquid fertilizer storage section. This is an example of multi-tiered plant arrangement. FIG. 13 is a schematic diagram showing another configuration example of the plant growing device. This is an example of piping connections.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In this embodiment, a plant growing device that grows plants using artificial light will be described. The plant growing device in this embodiment is disposed in, for example, a plant factory.
Here, the plant may be, for example, an agricultural crop such as a legume (immature/seed).

FIG. 1 is a schematic diagram showing an example of the schematic configuration of a plant growing device 100 according to the present embodiment.
The plant growing device 100 is arranged, for example, in a plant factory.
A cultivation rack (not shown) is arranged in the plant factory. The cultivation rack is a shelf that forms a cultivation space 40 in which the plants 200 are cultivated. The cultivation space 40 may be an open space or a closed space.
The plant 200 is supported by the cultivation panel 50. The cultivation panel 50 is a plate-shaped member that holds the plant 200. The cultivation panel 50 is provided with one or more through holes for planting the plant 200.

The upper side of the cultivation panel 50 is an above-ground space 210 where the stems of the plants 200 grow and the leaves spread out, and where most of the leaves and stems of the plants 200 are exposed. On the other hand, the lower side of the cultivation panel 50 is an underground space 220 where the liquid fertilizer storage section 31, the lower part of the stems of the plants 200 and the roots (tap root, lateral roots, etc.) are arranged, and where nutrient solution (liquid fertilizer) 32 is supplied to the roots.
The liquid fertilizer storage unit 31 is a storage container that stores liquid fertilizer 32 to be supplied to the plant 200, and is configured to be able to supply and discharge the liquid fertilizer 32. The supply and discharge of the liquid fertilizer 32 to the liquid fertilizer storage unit 31 is performed by a liquid fertilizer control unit 30 connected to the liquid fertilizer storage unit 31.

The plant growing device 100 in this embodiment irradiates artificial light onto the plant 200 in the cultivation space 40 from the side of the plant 200 in the above-ground space 210 of the plant 200 .
Specifically, the plant growing device 100 includes a light source (artificial light source) 10 that emits artificial light used for photosynthesis or the like of the plant 200. The light sources 10 are disposed opposite each other across the plant 200 in a direction (Y direction in FIG. 1 ) perpendicular to the growth direction (Z direction in FIG. 1 ) of the plant 200, and irradiate artificial light from both sides in the growth direction of the plant 200 in an above-ground space 210 of the plant 200.

In this embodiment, the cultivation space 40 includes a space in which the light source 10, the liquid fertilizer storage section 31, and the cultivation panel 50 are arranged, and a space that can be occupied by the plant 200 in the above-ground space 210.
The cultivation rack on which the plants 200 are arranged may be fixed or movable. When the cultivation rack is movable, the light source 10 may be fixed or may be configured to move together with the cultivation rack. The plants 200 may be arranged in multiple stages in the vertical direction (Z direction).
Furthermore, the plant growing device 100 may include a light source (artificial light source) disposed above the plant 200. In this case, artificial light can be irradiated from above the plant 200 as well.

[Artificial light source]
The light source 10 is disposed so that its light emitting surface faces a lateral region of the cultivation space 40 (a plane parallel to the XZ plane in FIG. 1), and irradiates the plant 200 with artificial light from the side thereof.
As a plant grows, it expands vertically. When a light source is placed above a plant and light is irradiated from above the plant, the light first reaches the topmost leaf of the plant. However, the light is less likely to reach the inside of the topmost leaf or the lower side of the leaf (lower part of the plant). In other words, the amount of light that reaches the leaves overlapping the irradiated leaf or the leaves located below the irradiated leaf is lower than the leaves located at the top of the plant where the light is reliably irradiated. Therefore, in the case of a particularly tall plant, a problem may occur in that photosynthesis is less likely to occur in the inner leaves (leaves closer to the stem) or the lower leaves of the plant.

In this embodiment, by irradiating the plant 200 with artificial light from the side in the growth direction (Z direction), an appropriate amount of light can be irradiated not only to the upper part of the plant 200 but also to the leaves located at the lower part of the plant 200.

2A, the light source 10 may be a surface-emitting light source in which a plurality of light-emitting elements, LEDs 12, are arranged on a flat support (support substrate) 11. The LEDs 12 mainly include an LED chip 12a that emits light, and an LED substrate 12b for supplying power to the LED chip 12a from a power supply device (not shown).
As shown in Fig. 2B, which is a view taken in the direction of the arrow A in Fig. 2A, the LEDs 12 can be arranged in a lattice pattern on the support substrate 11. The support substrate 11 can be, for example, an acrylic plate or an aluminum plate.

In the light source 10, light is emitted from the LED chip 12a, and heat is dissipated from the LED substrate 12b in association with the supply of power to the LED chip 12a. That is, the light emission direction 13 in which the light is emitted and the heat dissipation direction 14 are opposite to each other.
The LEDs 12 may emit light having different wavelengths. Also, the LEDs 12 may emit light having different wavelengths depending on the growth stage of the plant 200.

The configuration of the light source 10 is not limited to the configuration shown in FIGS. 2A and 2B.
For example, as shown in FIG. 3, a heat dissipation member 15 such as a heat sink may be disposed on the surface of the support substrate 11 opposite to the surface on which the LEDs 12 are disposed.

In addition, the support for supporting the LEDs 12 is not limited to being flat as described above, and the support surface may have a curved portion. For example, as shown in Fig. 4, the light source 10 may have a configuration in which a plurality of LEDs 12 are arranged on a corrugated support substrate 11a.
4, in the case of the corrugated support substrate 11a, the surface area of the LED mounting surface is increased compared to the flat support substrate 11, so it is possible to mount more LEDs 12. In addition, the surface area of the surface through which heat from the LEDs 12 is dissipated is also increased, so even if the number of LEDs 12 is increased, it is possible to dissipate heat efficiently.

The light source 10 may also be configured with multiple lamp light sources, each having a cylindrical light-emitting surface, arranged in parallel.

The size and shape of the light-emitting surface of the light source 10 may be equal to the size and shape of the lateral area of the cultivation space 40 that is the irradiated surface of the light. In this case, the light source 10 can irradiate the entire surface of the lateral area of the cultivation space 40 with artificial light uniformly or approximately uniformly.
In the plant growing device 100 shown in FIG. 1, the light sources 10 are disposed facing each other in the Y direction with the plant 200 in between, but the light sources 10 may be disposed on only one side of the plant 200.

[Air conditioning system]
The plant growing device 100 in this embodiment can be equipped with an air conditioning system as a blower that blows air and forms an air flow within the cultivation space 40.
1, the air conditioning system includes an air conditioning control unit 20, an air supply pipe 21, and an exhaust pipe 22. The air supply pipe 21 and the exhaust pipe 22 are connected to an air supply port 41 and an exhaust port 42, respectively, which will be described later.
The air conditioning control unit 20 adjusts the cultivation space 40 to a state suitable for growing the plant 200. Specifically, the air conditioning control unit 20 sends out air that has been adjusted so that the temperature, humidity, air volume, and carbon dioxide (CO ₂ ) concentration in the cultivation space 40 are suitable for growing the plant 200.

The air sent out by the air conditioning control unit 20 passes through the air supply pipe 21 and is supplied into the cultivation space 40 from an air supply port 41 provided below the plant 200. The air supplied from the air supply port 41 flows from bottom to top within the cultivation space 40, is exhausted from an exhaust port 42 provided above the plant 200, and is returned to the air conditioning control unit 20 through the exhaust pipe 22. In this way, the air conditioning system flows air into the cultivation space 40, performing air circulation.
The cultivation space 40 may be provided with sensors (not shown) for detecting the temperature, humidity, air volume, and carbon dioxide (CO ₂ ) concentration in the cultivation space 40. In this case, the air conditioning control unit 20 can adjust the temperature, humidity, air volume, and carbon dioxide (CO ₂ ) concentration of the air sent to the air supply pipe 21 based on the detection values of the sensors so that the temperature, humidity, air volume, and carbon dioxide (CO ₂ ) concentration in the cultivation space 40 are at predetermined states.

Here, the air inlet 41 and the exhaust outlet 42 may be openings having a predetermined length in the X direction (e.g., the same length as the cultivation space 40). Alternatively, the air inlet 41 and the exhaust outlet 42 may be a plurality of openings formed at predetermined intervals in the X direction. With this configuration, for example, as shown in Fig. 5, even when a plurality of plants 200 (six plants in this case) arranged in the X direction are cultivated in the cultivation space 40 and the cultivation space 40 is a space long in the X direction, air can be uniformly circulated in the cultivation space 40.
The shape, size, number and formation positions of the air supply port 41 and the air exhaust port 42 can be set as appropriate.

5, the air conditioning system may include an intake fan 23 and an exhaust fan 24. The intake fan 23 may be provided, for example, at a connection port between the intake pipe 21 and the cultivation rack forming the cultivation space 40. The exhaust fan 24 may be provided, for example, at a connection port between the exhaust pipe 22 and the cultivation rack forming the cultivation space 40. In this case, air can be actively circulated within the cultivation space 40.
The installation positions of the intake air fan 23 and the exhaust fan 24 are not limited to the positions shown in Fig. 5. The intake air fan 23 and the exhaust fan 24 may be installed at any position where a desired air flow can be formed in the cultivation space 40, and may be installed, for example, within the cultivation space 40. The air conditioning system may be configured to include only one of the intake air fan 23 and the exhaust fan 24.

Conventionally, as shown in Fig. 6, a light source 110 that emits light used for photosynthesis or the like of a plant 200 is disposed above the plant 200 in a space within a plant factory where the plant 200 is grown, and irradiates the plant 200 with light from above. In addition, a liquid fertilizer storage unit 131 is disposed below the plant 200, and liquid fertilizer is supplied to the plant 200.
The light source 110 has a relatively large shape in order to irradiate light to the multiple plants 200 arranged in not only the X direction but also the Y direction, and is not configured to allow air to flow vertically in the cultivation space for the plants 200. For this reason, in the past, the environment in the cultivation space was controlled by flowing air from the side relative to the growth direction of the plants 200, as shown by the arrows in Fig. 6.

However, if the plant 200 is a tall plant, the air flow becomes more difficult as the plant 200 grows, and the environment around the exhaust port may not be appropriately controlled. In addition, as shown in Fig. 6, when the light source 110 is disposed in the cultivation space, the supplied air flows while absorbing heat from the light source 110, and therefore, when the cultivation space is long in the X direction in particular, a large temperature gradient is generated between the air intake port side and the exhaust port side.
In order to optimize the temperature near the exhaust port, it is possible to lower the temperature of the air supplied to the cultivation space or increase the air volume, but in that case, the problem may arise that the environment near the air intake port is not suitable for the plant 200.

There is an appropriate wind volume for the growth of the plant 200, and the photosynthetic efficiency may change depending on the wind volume. For example, when the air is not moving, the layer of air with a low _CO2 concentration (leaf surface boundary layer) present on the surface of the leaves of the plant 200 becomes thick, and the photosynthetic efficiency decreases. By blowing wind on the surface of the leaves, the leaf surface boundary layer on the surface of the leaves can be destroyed (eliminated), and the photosynthetic efficiency can be improved. However, if the wind volume is too large, the plant 200 is stressed and the photosynthetic efficiency decreases.
In order to increase the photosynthetic efficiency of the plant 200, it is important to create a uniform air flow with an appropriate air volume for the plant 200.

The above problem may occur similarly in the case of lateral illumination in which light is irradiated onto the plant 200 from light sources 110 arranged opposite each other in the Y direction with the plant 200 in between, when air is caused to flow from the side relative to the growth direction of the plant 200, as shown in Figures 7A and 7B. Note that Figure 7A is a top view of the cultivation space in the case of lateral illumination, and Figure 7B is a side view in the case of lateral illumination.
Therefore, in the conventional air conditioning control described above in which air is blown from the side relative to the growth direction of the plant 200, a difference in growth is likely to occur between the plant 200 on the air intake side and the plant 200 on the exhaust side.

Therefore, in this embodiment, air conditioning control is performed to flow air in the growth direction (up and down direction) of the plant 200.
For this purpose, the liquid fertilizer storage section 31 arranged below the plants 200 is divided into multiple sections, and the multiple liquid fertilizer storage sections 31 supply liquid fertilizer 32 to the plants 200 arranged in a specific direction (X direction) for each row. Air supply ports 41 are provided between adjacent liquid fertilizer storage sections 31. This makes it possible to supply air to the cultivation space 40 from below.

In addition, the light source 10 is disposed to the side of the plant 200, and the exhaust port 42 is provided above the plant 200. This allows air supplied from below the cultivation space 40 to be properly exhausted from above.
In this way, by making the air flow in the cultivation space 40 for the plants 200 go from below to above, a uniform air flow can be formed even when tall plants 200 are densely cultivated in the cultivation space 40. Therefore, the temperature of the cultivation space can be made uniform while maintaining an air volume suitable for the plants 200. As a result, the difference in growth between individual plants can be suppressed.

Furthermore, in the present embodiment, when the cultivation space 40 is a space long in the X direction and the light-emitting surface of the light source 10 has a size and shape corresponding to the size and shape of the side region of the cultivation space 40, the length of the light-emitting surface of the light source 10 in the vertical direction (Z direction) is shorter than the length of the light-emitting surface in the direction perpendicular to the vertical direction (X direction). In other words, making the air flow in the cultivation space 40 for the plant 200 from below to above means making the air flow in the direction of the short side of the light-emitting surface of the light source 10.
In this embodiment, the light source 10 is disposed in the cultivation space 40, and the cultivation space 40 is not separated from the heat dissipation space of the light source 10. Therefore, the air supplied to the cultivation space 40 flows while absorbing heat from the light source 10. By making the air flow in the direction of the short side of the light emitting surface of the light source 10 as described above, it is possible to suppress the generation of a large temperature gradient between the air intake port 41 side and the air exhaust port 42 side.

In addition, since warm air rises, by directing the air flow in the cultivation space 40 from bottom to top, the warm air in the cultivation space 40 can be exhausted without diffusing.

[Liquid fertilizer storage section]
Returning to FIG. 1 , the liquid fertilizer storage section 31 is connected to the liquid fertilizer control section 30 by a liquid fertilizer piping 33 , and the supply and discharge of liquid fertilizer 32 to the liquid fertilizer storage section 31 is controlled by the liquid fertilizer control section 30 .
The plant growing device 100 in this embodiment includes a mechanism for actively dissipating heat from the light source 10. Specifically, the plant growing device 100 includes a heat dissipation unit that dissipates heat from the light source 10 by using liquid fertilizer 32. By dissipating heat from the light source 10 by using liquid fertilizer 32, the amount of heat dissipated from the light source 10 to the space can be reduced. Therefore, the impact of heat from the light source 10 on the cultivation space for the plant 200 can be more appropriately reduced.

The heat dissipation section is a member that is in contact with the support substrate 11 of the light source 10 and the liquid fertilizer 32 contained in the liquid fertilizer storage section 31. For example, the heat dissipation section can be an end of the support substrate 11 of the light source 10 immersed in the liquid fertilizer 32 as shown in Fig. 1. By immersing the end of the support substrate 11 in the liquid fertilizer 32 as shown in Fig. 1, the heat of the light source 10 can be directly released to the liquid fertilizer 32. Note that in Fig. 1, the support substrate 11 is also in contact with the liquid fertilizer storage section 31 within the liquid fertilizer storage section 31, but it is sufficient that the support substrate 11 is in contact with at least the liquid fertilizer 32.
The liquid fertilizer control unit 30 may also include a cooling unit 30a for lowering the temperature of the liquid fertilizer 32 in the liquid fertilizer tank. The cooling unit 30a may be, for example, a chiller-type aquarium cooler. This allows the liquid fertilizer 32 that has absorbed heat from the light source 10 to be appropriately cooled, and the temperature rise of the liquid fertilizer 32 to be suppressed.

Furthermore, the heat dissipation section may be, for example, a liquid fertilizer storage section (storage container) 31 with which a part of the support substrate 11 of the light source 10 is in contact. In this case, as shown in Fig. 8, the support substrate 11 may be in contact with the liquid fertilizer storage section 31 without being immersed in the liquid fertilizer 32. With this configuration, the heat of the light source 10 can be released to the liquid fertilizer 32 via the liquid fertilizer storage section 31. Furthermore, since the support substrate 11 does not need to be immersed in the liquid fertilizer 32, there is no risk of the support substrate 11 being corroded or short-circuited by the liquid fertilizer 32.
Here, the liquid fertilizer storage section 31 may be made of a material with high thermal conductivity, such as a metal. In this case, the heat of the light source 10 can be more efficiently dissipated to the liquid fertilizer 32. As the metal, for example, aluminum can be used.

9, the heat dissipation section may be a heat dissipation plate 35 that is disposed in the liquid fertilizer storage section 31 and contacts at least a part of the support substrate 11 and the liquid fertilizer 32. In this case, the support substrate 11 may be in contact with the heat dissipation plate 35 without being immersed in the liquid fertilizer 32. Here, the heat dissipation plate 35 is preferably made of a material with high thermal conductivity, such as a metal.
With this configuration, even if the liquid fertilizer storage section 31 is not made of a metal with high thermal conductivity, it is possible to dissipate heat from the light source 10 to the liquid fertilizer 32. In addition, since the support substrate 11 is not immersed in the liquid fertilizer 32, there is no risk of the support substrate 11 being corroded or short-circuited by the liquid fertilizer 32.

In this way, by dissipating the heat of the light source 10 to the liquid fertilizer 32 using the heat dissipation section, the amount of heat dissipated by the light source 10 into the heat dissipation space can be reduced. Since the existing liquid fertilizer circulation can be used to dissipate heat from the light source 10, there is no need to install a new water cooling system or the like. This makes it possible to prevent the device from becoming larger and achieve cost reductions.

FIG. 10 is a diagram showing an example of the configuration of the liquid fertilizer storage section 31.
The cultivation rack 300 includes a horizontally disposed support frame 301 and a plurality of support plates 302 supported by the support frame 301. The plurality of support plates 302 each extend in the Y direction and are arranged in parallel at a predetermined interval in the X direction. The shape of the cultivation rack 300 is not limited to the above.

The liquid fertilizer storage sections 31 extend in the X direction on the support plate 302 of the cultivation rack 300 and are arranged at predetermined intervals in the Y direction.
Cultivation panels 50 that support plants are placed on the liquid fertilizer storage section 31. Fig. 10 shows an example in which three cultivation panels 50 are placed on one liquid fertilizer storage section 31 extending in the X direction. In this case, gap panels 51 that do not have through holes for planting plants may be placed between the cultivation panels 50.
Although not shown in Figure 10, the cultivation panels 50 may be placed on all of the liquid fertilizer storage sections 31.

The liquid fertilizer storage sections 31 are connected to one end side and the other end side in the X direction, respectively, and it may be possible to collectively supply liquid fertilizer 32 to the liquid fertilizer storage sections 31 and collectively discharge liquid fertilizer 32 from the liquid fertilizer storage sections 31. In this case, liquid fertilizer pipes 33 are connected to the connecting sections that connect the liquid fertilizer storage sections 31 at both ends of the liquid fertilizer storage sections 31 in the X direction, respectively.
Furthermore, the plant cultivation device 100 in this embodiment may include a sensor 31a that detects the temperature of the liquid fertilizer 32 contained in the liquid fertilizer container 31. The liquid fertilizer control unit 30 may control the temperature of the liquid fertilizer 32 contained in the liquid fertilizer container 31 to a temperature suitable for the plant, based on the value detected by the sensor 31a.
In addition, the mounting position of the sensor 31a is not particularly limited. In addition, in the example shown in Fig. 10, the case where a plurality of liquid fertilizer storage units 31 are connected in parallel is described, but the method of connecting the liquid fertilizer pipes 33 is not particularly limited.

A light source 10 is arranged between adjacent liquid fertilizer storage sections 31. In this case, as shown in FIG. 10, multiple (three in this case) light sources 10 may be arranged at a predetermined interval in the X direction. However, the arrangement of the light sources 10 is not limited to the above. For example, the light sources 10 may be arranged without gaps from one end to the other end of the liquid fertilizer storage section 31 in the X direction.

FIG. 11 shows an example of an arrangement in which plants 200 are arranged vertically in multiple tiers.
In the plant cultivation room 500 , a partition material 210 such as a vinyl curtain is installed from the floor 501 to the ceiling 502 , and the partition material 210 divides the plant cultivation room 500 into an air supply space 511 and an exhaust space 512 .
The air supply space 511 is a space for supplying air conditioned by the air conditioning control unit 20 to the cultivation space 40, and corresponds to the air supply pipe 21 shown in Fig. 1. The exhaust space 512 is a space for returning air exhausted from the cultivation space 40 to the air conditioning control unit 20, and corresponds to the exhaust pipe 22 in Fig. 1.

The air in the air supply space 511 is supplied to the cultivation space 40 by, for example, an air supply fan 23 installed in the support frame 301 of the cultivation rack 300. The air supplied to the cultivation space 40 flows upward between the light sources 10 through the gaps in the support plate 302 of the cultivation rack 300, through the gaps between the liquid fertilizer storage parts 31, and is exhausted to the exhaust space 512 by, for example, an exhaust fan 24 installed in the support frame 301 of the cultivation rack 300.
Here, the cultivation rack 300 may be provided with a wind control plate 25 that divides the upper and lower cultivation spaces 40. By installing the wind control plate 25, it is possible to prevent the air (warm air) exhausted from the lower cultivation space 40 from being supplied to the upper cultivation space 40.

As described above, the plant growing device 100 in this embodiment includes the light source 10 that irradiates the plant with the artificial light. The light source 10 has a support substrate 11 on which the LEDs 12, which are light emitting elements, are arranged. The plant growing device 100 also includes a liquid fertilizer storage section 31 having a storage container that stores liquid fertilizer 32 to be supplied to the plant 200, and a heat dissipation section that is in contact with the support substrate 11 and the storage container and dissipates heat from the light source 10 to the liquid fertilizer 32.
In other words, the plant cultivation method in this embodiment includes a step of irradiating artificial light from a light source 10 to a plant 200, and a step of bringing a heat dissipation part into contact with a support substrate 11 of the light source 10 and liquid fertilizer 32 supplied to the plant 200, thereby dissipating heat from the light source 10 to the liquid fertilizer 32.

In this way, the plant growing device 100 in this embodiment dissipates heat from the light source 10 by using the liquid fertilizer 32. This reduces the amount of heat dissipated from the light source 10 into the space, and more appropriately reduces the impact of the heat from the light source 10 on the cultivation space 40 for the plant 200.

Here, the heat dissipation portion may be an end portion of the support substrate 11 immersed in the liquid fertilizer 32. In this case, heat from the light source 10 can be dissipated directly into the liquid fertilizer.
The heat dissipation section may be, for example, a container made of metal that is in contact with a part of the support substrate 11. In this case, heat from the light source 10 can be released to the liquid fertilizer 32 via the container for storing the liquid fertilizer.
Furthermore, the heat dissipation part may be a heat dissipation plate 35 that is disposed in the storage container and contacts at least a part of the support substrate 11 and the liquid fertilizer 32. In this case, for example, even if the storage container for the liquid fertilizer 32 is made of a material with low thermal conductivity, the heat from the light source 10 can be dissipated to the liquid fertilizer 32 via the heat dissipation plate 35.

The plant growing device 100 may further include a cooling section 30a that cools the liquid fertilizer 32 stored in the liquid fertilizer storage section 31. In this case, the liquid fertilizer 32 that has absorbed the heat from the light source 10 can be appropriately cooled, and the temperature rise of the liquid fertilizer 32 can be suppressed.

As described above, in the plant growing device 100 of this embodiment, the amount of heat dissipated from the light source 10 in the cultivation space can be reduced by dissipating the heat of the light source 10 to the liquid fertilizer 32. This can reduce the cost of air conditioning control of the cultivation space. In addition, it is easy to uniformize the environment in the cultivation space, which can reduce differences in growth between individual plants.

(Modification)
In the above embodiment, the light source 10 is disposed on the side of the cultivation space 40, and lateral illumination is performed in which light is irradiated from the side of the plant 200. However, the light source 10 may be disposed above the cultivation space 40, and upward illumination may be performed in which light is irradiated from above the plant 200.
In this case, the light source 10 and the liquid fertilizer storage section 31 are arranged vertically on either side of the plant 200, so that when multiple plants 200 are arranged in multiple vertical tiers, the liquid fertilizer storage section 31 on the upper tier and the light source 10 on the lower tier are arranged adjacent to each other in the vertical direction.
In this case, the heat from the lower light source 10 may be dissipated by utilizing the liquid fertilizer 32 contained in the upper liquid fertilizer storage section 31. In other words, the support substrate 11 of the lower light source 10 may be bent and extended upward to be immersed in the liquid fertilizer 32 contained in the upper liquid fertilizer storage section 31, or the support substrate 11 of the lower light source 10 may be brought into contact with the upper liquid fertilizer storage section 31 directly or via a heat sink.
In addition, in the case of upward illumination, an exhaust outlet 42 can be provided above the plant 200 by dividing the light source 10 placed above into multiple parts, so that it is possible to form an upward and downward air flow within the cultivation space 40.

Furthermore, in the above embodiment, a case has been described in which the air flow direction in the cultivation space 40 is set from bottom to top by providing an air intake 41 below the plant 200 and an exhaust vent 42 above the plant 200. However, the air flow direction is not particularly limited. For example, the air intake vent 41 may be provided above the plant 200 and an exhaust vent 42 may be provided below the plant 200, and the air flow direction in the cultivation space 40 may be set from top to bottom.

In the above embodiment, the plant growing device 100 may include a housing 40A that forms a closed space surrounding the plant 200, as shown in Fig. 12. In this case, the closed space within the housing 40A can be used as the cultivation space 40.
The housing 40A surrounds the plant 200 in the above-ground space 210 of the plant 200 to form a closed space. The shape and size of the housing 40A are not particularly limited. Furthermore, the number of plants of the plant 200 cultivated in the housing 40A is not particularly limited.
The light source 10 is disposed outside the housing 40A such that its light emitting surface faces a side surface of the housing 40A (a surface parallel to the XZ plane in FIG. 1) and irradiates the plant 200 with artificial light from the side.
The housing 40A is made of a material that is optically transparent to the artificial light emitted from the light source 10. For example, the housing 40A can be made of a glass material that transmits artificial light, or a transparent resin material such as an acrylic material or a PET material.
With this configuration, the artificial light emitted from the light source 10 passes through the housing 40A and is irradiated onto both sides of the plant 200.

In this case, the air intake port 41 and the exhaust port 42 may be provided in the housing 40A. The air intake port 41 may be provided in the lower part of the housing 40A, and the exhaust port 42 may be provided in the upper part of the housing 40A. Specifically, the air intake port 41 may be provided in the bottom surface of the housing 40A, and the exhaust port 42 may be provided in the top surface of the housing 40A. In this case, the air supplied from the air intake port 41 flows from bottom to top inside the housing 40A and is exhausted.

Here, the housing 40A can surround the plants 200 arranged in a specific direction (X direction) by row. In addition, the multiple liquid fertilizer storage units 31 can be arranged outside the housing 40A to correspond to each of the multiple housings 40A. The liquid fertilizer storage units 31 are arranged facing each other on part of the bottom surface of the housing 40A, and an air supply port 41 is formed in the remaining area of the bottom surface of the housing 40A. This allows the air supply port 41 to be provided between adjacent liquid fertilizer storage units 31 among the multiple liquid fertilizer storage units 31, making it possible to supply air from below to the cultivation space 40 of the plants 200.

In this manner, the housing 40A may separate the cultivation space 40 for the plant 200 from the heat dissipation space for the light source 10. This allows the cultivation space 40 for the plant 200 to be configured to be less susceptible to the effects of heat from the light source 10. Therefore, the air conditioning control unit 20 can perform air conditioning control that is more specialized for the plant 200.
Also, the liquid fertilizer storage unit 31 can be disposed outside the housing 40A to separate the cultivation space 40 of the plant 200 from the liquid fertilizer space. Therefore, the liquid fertilizer control unit 30 can independently control the temperature of the liquid fertilizer 32 without being affected by the temperature of the cultivation space 40 of the plant 200. Furthermore, by separating the cultivation space 40 of the plant 200 from the liquid fertilizer space, it is possible to avoid the influence of the liquid fertilizer 32 on the humidity of the cultivation space 40. Therefore, the air conditioning control unit 20 can perform air conditioning control specialized for the plant 200.

In the example shown in Fig. 1, a case where a plurality of liquid fertilizer storage units 31 are connected in parallel has been described, but as shown, for example, in Fig. 13, a plurality of liquid fertilizer storage units 31 may be connected in series by a liquid fertilizer pipe 33 connected to the liquid fertilizer control unit 30 and a connection pipe 34 connecting the liquid fertilizer storage units 31 to each other. In this case, too, the liquid fertilizer 32 can be circulated appropriately.
13, the intake air pipe 21 and the exhaust air pipe 22 may be configured such that one end is connected to the air conditioning control unit 20 and the other end is connected to each of the multiple housings 40. With this configuration, air sent out from the air conditioning control unit 20 is supplied to the inside of each housing 40 through the intake air pipe 21, and the air that has passed through the inside of each housing 40 is returned to the air conditioning control unit 20 through the exhaust air pipe 22.
The method of connecting the air supply pipe 21, the exhaust pipe 22, and the liquid fertilizer pipe 33 is not limited to the method shown in FIG.

In the above embodiment, the plant growing device 100 is described as including the air conditioning control unit 20, but the plant growing device 100 does not have to include the air conditioning control unit 20. In this case, the plant growing device 100 only needs to include a fan that can circulate the necessary air in the cultivation space 40.
Furthermore, in the above embodiment, the plant growing device 100 is described as including the liquid fertilizer control unit 30, but if there is no need to control the temperature of the liquid fertilizer 32, the plant growing device 100 does not need to include the liquid fertilizer control unit 30. In this case, it is sufficient that the plant growing device 100 is provided with a mechanism capable of refilling the liquid fertilizer storage unit 31 with the liquid fertilizer 32.

Furthermore, in the above embodiment, the plant 200 to be grown is a legume such as soybean, but the plant 200 is not limited to legumes and may be any plant that can be grown using artificial light.

The plant cultivation device according to the present invention can increase agricultural production and achieve stable harvests. This corresponds to Goal 2 of the United Nations-led Sustainable Development Goals (SDGs) "End hunger, achieve food security and improved nutrition and promote sustainable agriculture" and also contributes greatly to Target 2.1 "By 2030, eradicate hunger and ensure access to safe, nutritious and sufficient food for all people, in particular the poor and vulnerable, including children, all year round."

10...artificial light source, 11...support substrate, 12...LED, 20...air conditioning control unit, 21...air supply pipe, 22...exhaust pipe, 23...air supply fan, 24...exhaust fan, 30...liquid fertilizer control unit, 31...liquid fertilizer storage unit, 32...liquid fertilizer, 33...liquid fertilizer pipe, 34...connection pipe, 35...heat sink, 40...cultivation space, 40A...casing, 41...air supply port, 42...exhaust port, 50...cultivation panel, 100...plant cultivation device, 200...plant, 300...cultivation rack

Claims (18)

A plant growing device for growing plants using artificial light,
an artificial light source having a light-emitting element and a support substrate on which the light-emitting element is arranged, the artificial light irradiating the plant with the artificial light;
A liquid fertilizer storage unit having a storage container for storing liquid fertilizer to be supplied to the plant;
A heat dissipation section that contacts the support substrate and the liquid fertilizer contained in the storage container and dissipates heat from the artificial light source to the liquid fertilizer;
A plant growing device comprising: The plant growing device according to claim 1, characterized in that the heat dissipation part is an end part of the support substrate and is immersed in the liquid fertilizer. The plant growing device according to claim 1, characterized in that the heat dissipation unit is the container with which a portion of the support substrate is in contact. The plant growing device according to claim 3, characterized in that the storage container is made of metal. The plant growing device according to claim 1, characterized in that the heat dissipation unit is a heat dissipation plate disposed within the container and in contact with at least a portion of the support substrate and the liquid fertilizer. The plant growing device according to claim 1, further comprising a cooling unit that cools the liquid fertilizer contained in the liquid fertilizer container. an air supply port provided above or below the plant to supply air to a cultivation space in which the plant is cultivated;
An exhaust port provided above or below the plant and configured to exhaust air from within the cultivation space;
The plant growing device according to claim 1, further comprising: The air intake is provided below the plant,
The plant growing device according to claim 7 , wherein the exhaust port is provided above the plant. The plant growing device according to claim 7, further comprising a blower unit that blows air and creates an air flow in the cultivation space. The plant growing device according to claim 9, characterized in that the air blowing unit is equipped with a fan. The plant growing device according to claim 9 , wherein the air blowing unit includes an air conditioning control unit that controls at least one of a temperature, a humidity, an air volume, and a CO ₂ concentration in the cultivation space. The plant growing device according to claim 1, characterized in that the artificial light source is arranged to irradiate the artificial light from a side relative to the growth direction of the plant. The plant growing device according to claim 12, characterized in that the vertical length of the light-emitting surface of the artificial light source is shorter than the length of the light-emitting surface in a direction perpendicular to the vertical direction. The liquid fertilizer storage unit further includes a plurality of liquid fertilizer storage units arranged below the plants and configured to store liquid fertilizer to be supplied to the plants.
The plurality of liquid fertilizer storage units are arranged at intervals so as to supply the liquid fertilizer to the plants arranged in a specific direction for each row,
The plant growing device according to claim 7 , wherein either the air supply port or the exhaust port is provided between adjacent liquid fertilizer storage units. A sensor for detecting the temperature of the liquid fertilizer stored in the liquid fertilizer storage section;
The plant growing device according to claim 1, further comprising a liquid fertilizer control unit that controls a temperature of the liquid fertilizer stored in the liquid fertilizer storage unit based on a detection value by the sensor. Further comprising a housing forming a closed space surrounding the plant;
The housing is light-transmissive to the artificial light,
The plant growing device according to claim 1 , wherein the artificial light source is disposed outside the housing and irradiates the plant with the artificial light through the housing. The plant growing device according to claim 16, characterized in that the housing surrounds the plants arranged in a specific direction in rows. A method for growing plants using artificial light, comprising:
irradiating the plant with artificial light from an artificial light source;
A step of contacting a heat dissipation unit with a support substrate on which a light emitting element of the artificial light source is arranged and liquid fertilizer to be supplied to the plant, thereby dissipating heat from the artificial light source to the liquid fertilizer;
A plant cultivation method comprising the steps of:

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