WO2008111830A1

WO2008111830A1 - Method and system for growing plants

Info

Publication number: WO2008111830A1
Application number: PCT/NL2007/000073
Authority: WO
Inventors: Gerardus Johannes Wilhelmus Peek; Antonius Maria Adrianus Hoogenboom; Cornelis Jan Matthieu Buis
Original assignee: Frans Van Zaal Totaal Techniek
Priority date: 2007-03-15
Filing date: 2007-03-15
Publication date: 2008-09-18
Also published as: EP2129211A1

Abstract

In a method for growing plants in a controlled environment, a first plant is positioned in a first controlled environment (12) and a second plant is positioned in a second controlled environment 16). In order to lower an energy-consumption, the method comprises - during a first time period, providing a day-time lighting condition in the first controlled environment (12) and nighttime lighting condition in the second controlled environment (16); - during a second time period, providing the night-time lighting condition in the first controlled environment (12) and the daytime lighting condition in the second controlled environment (16); and - exchanging heat between the first controlled environment and the second controlled environment for controlling a temperature in the first controlled environment and a temperature in the second controlled environment. The first time period and the second time period are alternated. Thus, for example, during daytime, heat is received from sunlight in the first environment (12) and the heat may be spread through both the first and the second controlled environment (16). Further, for example, during nighttime, lighting is provided in the second environment for generating a daytime lighting condition, thereby generating heat, which heat may be spread through both environments (12,16). The present invention further provides a construction configured for performing the method.

Description

Title: Method and system for growing plants

The present invention relates to a method and a system for growing plants and in particular to a method for growing plants in a controlled environment and a construction for growing plants, wherein the construction comprises a controlled environment.

It is known to grow plants in a protected and climate controlled environment. For example, a greenhouse may provide such a controlled environment. In the controlled environment, a temperature and humidity may be controlled. Other aspects of the environment may as well be controlled such as a gas composition (e.g. O₂, CO₂, N₂) and an amount of direct sunlight, for example.

A known greenhouse has a one-layer structure. The greenhouse is build on the ground and one layer of plants are arranged in the greenhouse. The plants may be positioned in moveable containers, for example. Due to the one-layer arrangement, a relatively large area is required for a sufficient amount of plants in order to generate a profitable business.

The relatively large area that is required has a number of disadvantages. First, the large area is relatively expensive to buy or to rent. Second, the large area requires a large greenhouse, which is expensive. Further^ the large greenhouse has a relatively large glass roof, which allows a large amount of daylight / sunlight into the greenhouse. The large amount of sunlight may result in a relatively high temperature in the greenhouse. Therefore, it is known to provide glass windows in the roof that may be opened, when the temperature becomes to high. However, opening such windows letting hot air leave is an inefficient use of (collected) energy.

It is an object of the present invention to provide a method and system for growing plants with an efficient use of energy.

The object is achieved in a method according to claim 1 and a construction according to claim 15.

In the method according to the present invention, a first number of plants are positioned in a first controlled environment and a second number of plants are positioned in a second controlled environment. In a first time period, the plants in the first controlled environment receive light, i.e. in a daylight condition, whereas the second number of plants is kept in the dark, i.e. in a night condition. In a second time period, the lighting condition is reversed: the plants in the second controlled environment receive light, i.e. in a daylight condition, whereas the first number of plants is kept in the dark, i.e. in a night condition. The first and the second time periods are alternated such that the first and the second number of plants each experience a day-and-night rhythm.

The daylight condition may be generated by use of lamps or may be received from an outside daylight condition. In both cases heat is collected in the environment having a daylight condition. Therefore, in order to generate a desired temperature in the other controlled environment, having a night condition, heat is exchanged between the first and the second controlled environment. Thus, any surplus of heat in the daylight-conditioned controlled environment may be transferred to the nightlight-conditioned controlled environment. In such a method, multiple layers of plants may be used. Since at least a part of the plants are to be lighted by lamps, this part of the plants need not be positioned below a glass roof, but may be positioned below a container of other plants. Moreover, in order not to disturb their day-and-night rhythm, these plants should not receive light in the period that they are expected to be in a night condition. Therefore, the first and/or the second environment may be arranged in a closed construction that does not allow entering of daylight from outside. Thus, in an embodiment, the first time period is a day-time period and the second time period is a night-time ^■ period and the method comprises during day-time, receiving daylight in the first controlled environment and blocking daylight from entering the second controlled environment; and during night-time, generating a predetermined lighting condition in the second controlled environment simulating a daylight condition.

In an embodiment, the exchange of heat is performed by circulating air between the first and the second environment, which allows for a energy-efficient exchange of heat. As a further advantage, an air condition such as temperature or humidity may be controlled by a single device for both controlled environments. Preferably, the air circulation is a forced air circulation, e.g. forced by a fan, or the like. If the air circulation is forced, it may as well be controlled. For example, an amount of air per unit time and/or an air velocity may be controlled. In an embodiment at least one of the first and the second controlled environment is divided in a number of- grow environment areas. For example, in one of the controlled environments, multiple layers of plants may be arranged. In such a case, if the air circulation is forced and controlled, the air circulation may be controlled per grow environment area, i.e. per layer. Thus, depending on the kind of plants and the stage of growth of the plant and possibly other aspects, the air circulation may be set.

As mentioned above, in an embodiment, a condition of the air may be controlled. In particular, an air condition of the circulating air and/or an air condition of the air in the first controlled environment and/or an air condition of the air in the second controlled environment may be controlled in order to provide a desirable climate for the plants to grow. For example, temperature and humidity may be controlled. Also other air condition aspects may be controlled.

In an embodiment, the plants are positioned in a container and ^■ the method further comprises determining a weight of a container holding a number of plants and determining from the determined weight a soil humidity of the soil (grow medium) on which the plants are growing. Based on the determined soil humidity a predetermined amount of water is supplied to the plants in order to obtain a desired soil humidity. The desired soil humidity may be dependent on the kind of plant and its grow stage. Further the desired soil humidity may be dependent on the environmental conditions and the resulting vaporization of the water from the plants and from the soil. It is noted that such a method of supplying water to plants may as well be used in any other plant growing method and is not limited to growing plants in accordance with the method as described above.

In an embodiment, the method comprises acquiring an infrared- radiation image of a plant. Based on the radiated infrared rays, a surface temperature of the plant may be determined. The surface temperature of the plant may be advantageously used to determine a condition of the plant. Like humans and animals, when the immune system of the plants is activated by pathogenic organism, the temperature, and thus the surface temperature, is raised. Such an increase in surface temperature may be determined before it becomes visible that a plant is infected..Detecting an infection in an early stage is advantageous, since an infected plant may be isolated to prevent infection of other plants, for example. In an embodiment, wherein a plant is positioned in a container, the container having a gas-transmissive base, the method comprises generating an air circulation in a loop, wherein the loop runs from above the plant, alongside the container to below the container, through the base of the container, past the plant to above the plant. Preferably, the air circulation loop further runs through an air conditioning area for controlling a condition of the air. Such an arrangement is energy-efficient and may advantageously be employed in combination with multiple layers of plants.

The present invention further provides a construction for performing the above described method. The construction for growing plants in a controlled environment comprises a first controlled environment configured to provide a day-time lighting condition during a first time period and to provide a night-time lighting condition during a second time period; and a second controlled environment configured to provide a night-time lighting condition during the first time period and to provide a day-time lighting condition during the second time period. Further, the first controlled environment and the second controlled environment are coupled such that heat is exchangeable between the first controlled environment and the second controlled environment.

The construction according to the present invention may further be configured for performing any embodiment of the method according to the present invention.

Hereinafter, the present invention is elucidated with reference to the appended drawings showing non-limiting embodiments, wherein:

Fig. IA is a cross-sectional view of an embodiment of a construction according to the present invention; and

Fig. IB is an enlarged part of the cross-sectional view of Fig. IA.

In the drawings, like reference numerals refer to like elements. Fig. 1 shows a cross-sectional view of a greenhouse construction 10 for performing the method according to the present invention. The greenhouse construction 10 comprises a first controlled environment 12 arranged below a glass roof 14 of the greenhouse construction 10. The glass roof 14 may of course as well be manufactured from any other light-transmissive material, such as a suitable transparent plastic material. Also other walls and elements of the greenhouse 10 may be constructed from glass, plastic material, steel or any other suitable material. The roof 14 may be provided with ventilation means, e.g. a window that may be opened. The ventilation means may be used for cooling in case a temperature inside the greenhouse 10 becomes too high, for example due to a failure of a cooling system as below described.

Below the first controlled environment 12, a second controlled environment 16 is arranged. The second controlled environment 16 is divided in six grow environment areas 16A - 16F. In the first controlled environment 12 and the second controlled environment 16, a number of plant containers 18 are positioned. The plant containers 18 are, preferably movably, supported by a suitable support structure 20.

The first controlled environment 12 and the second controlled environment 16 are separated by a separation construction 22, which in the illustrated embodiment is provided with airflow guiding means. The airflow guiding means comprise first airflow blocking elements 24, second airflow blocking elements 26A, 26B, third airflow blocking elements 28A, 28B, fourth airflow blocking elements 3OA, 3OB, and fifth airflow blocking elements 32A, 32B. On top of the first airflow blocking means 24 a support 34 is arranged to provide a path for persons to walk between the plant containers 18 in the first controlled environment 12. It is noted that in the illustrated embodiment the separation construction 22 is also configured to support the plant containers 18 in the first controlled environment 12.

In the second controlled environment 16, a first separation means 36A and a second separation means 36B are provided. Each of the separation means 36A - 36B extend between a floor 38 of the second controlled environment 16 and the separation construction 22. The first separation means 36A separates a first part of the second controlled environment 16, whereas the second separation means 36B separates a second part of the second controlled environment 16. In said first part a first, second and third grow environment area 16A - 16C is formed e.g. by the plant containers 18 as illustrated in Fig. 1. Similarly, in said second part a fourth, fifth and sixth grow environment area 16D - 16F is formed e.g. by the plant containers 18. Between the first and the second separation means 36A, 36B an air conditionings area 42 is arranged. In the first and second separation means 36A, 36B first, second, third, fourth, fifth, and sixth airflow generation means 44A - 44F are provided for generating an airflow from the air conditionings area 42 to each of the grow environments areas 16A - 16F, respectively.

Fig. IB shows an enlarged part of the view of Fig. IA, which part is indicated in Fig. IA by a dashed rectangle with reference B. In Fig. IB air conditioning means 46 are indicated. The air conditioning means 46 may include means to heat, to cool, to hydrate and/or to dehydrate the air passing the air conditioning means 46. Of course, the air conditionings means may be separated in a number of air conditioning devices, e.g. one for heating, one for cooling, one for (de) hydrating, etc. Also other air conditioning means may be provided, for example for controlling a gas composition of the air, an air pressure, an airflow rate, or any other air condition. Likewise, means for killing and/or removing bacteria and/or other harmful organisms from the circulating air may be present to prevent that a disease is spread throughout the controlled environments 12, 16.

Referring to Fig. IA again, the grow environment areas 16A - 16F are provided with suitable lighting means in order to provide a suitable lighting condition in the respective grow environment areas 16A- 16F. Further, watering means may be provided and other control and/or inspection means, such as cameras, possibly infrared radiation cameras and/or visible radiation cameras. However, these means may also be provided at a different location, in particular if the plant containers 18 are movably supported, such that the plant containers 18 may be moved to the location where the watering means and/or inspection means are arranged.

In operation, the airflow generation means 44A - 44F generate an airflow in the first and the second controlled environment 12, 16. The airflow is indicated by the arrows 48A - 48P. For example, starting from the first airflow generation means 44A, which may be a fan, for example, an airflow indicated by arrow 48A is generated from the first separation means 36A through the first grow environment area 16A. The airflow is guided through the separation construction 22 and then to the first controlled environment 12 as indicated by the arrows 48G and 48H. The airflow generated by the first airflow generation means 44A is sucked in from the air conditionings area 42. The air in the air conditionings area 42 is sucked in from the first controlled environment 12 as indicated by the arrows 481, 48J and 48K. Thus, an air circulation loop 48A-48G-48H-48I-48J-48K is generated. Further, a second similar air circulation loop 48D-48L- 48M-48N-48O-48P is also generated by the fourth air circulation means 44D. This construction using a central air conditionings area 42 and air circulation means 44A - 44F provides a high degree of freedom for generating separate grow condition areas, as below elucidated, while being very energy efficient in respect of the energy that is required for generating the air circulation and in respect of the energy required for conditioning the air.

Said air circulation loops are further supported by the second, third, fifth and sixth air circulation means 44B, 44C, 44E, 44F. In order to allow such an air circulation, the plant containers 18 may have a gas permeable bottom. Thus, for example, an airflow generated by the second air circulation means 44B may pass through the bottom of the plant container 18 as indicated by the arrow 48B. It is noted that the airflow from below passing through the bottom and along the plants in the plant container 18 may have a positive influence on the growth of the plants. Likewise, the air circulation means 44A - 44F may be selected, arranged and controlled to provide a suitable airflow for plant growth, since the airflow may influence the growth of the plants.

In the illustrated embodiment of the second controlled environment 16 having the six separated grow environment areas 16A - 16F, each grow environment area 16A - 16F may have a predetermined air condition suitable for the grow of the plants in the respective grow environment areas 16A - 16F. For example, the air condition in the second grow environment area 16B may be controlled by controlling the rate of the airflow generated by the second air circulation means 44B, supplying air from the air conditioning area 42 to the second grow environment area 16B. The air condition of the air in the air conditionings area 42 is controllable by the air conditioning means 46. The air condition in the second grow environment area 16B is further dependent on the rate of the airflow from the third grow environment area 16C as indicated by the airflow arrow 48C, which is dependent on an airflow rate of the third air circulation means 44C. Further, the air condition of the air in the second grow environment area 16B may be dependent on the lighting condition. In particular, a lamp, such as a incandescent lamp, a halogen lamp, a discharge lamp, an LED or any other kind of lamp, generates visible radiation, invisible radiation and heat. The invisible radiation may heat the plants, resulting in heating of the air, and the heat generated by the lamp inevitably heats the air in the grow environment area 16B, which subsequently flows to the first grow environment area 16A and from there to the first controlled environment 12, thus taking the generated heat from the second controlled environment 16 to the first controlled environment 12. This aspect of a surplus of heat due to lighting may be advantageously employed in accordance with the present invention, as is explained below.

In an embodiment of a method according to the present invention, the first controlled environment 12 receives light, in particular daylight, during a first time period, in particular during the day, through the glass roof 14. The received daylight includes and will generate heat in the first controlled environment 12, as is well known from the prior art. The air in the first controlled environment 12 is thereby heated and the heated air is circulated through the first and the second controlled environment 12, 16. Due to the layered structure of the greenhouse 10, more plants are present per unit area of the greenhouse 10 and the heat from the received daylight may be used more efficiently. In an optimal configuration and situation there is no surplus heat in the greenhouse 10, and therefore, no heat needs to be removed from the greenhouse 10 by ventilation, for example.

The above-mentioned first time period is alternated with a second time period, in the presently described embodiment being a nighttime period. During the second time period, no light and thus substantially no heat is received in the first controlled environment 12. In the second time period the lights are switched on, whereas these lights were switched off during the first time period. The heat generated by the lights in the second controlled environment 16 as a side effect of the lighting is now advantageously employed to heat the air, which is circulated through the first and the second controlled environment 12, 16. Thus, the plants in the second controlled environment 16 have a day and night rhythm that is reversed with respect to the natural day-and-night rhythm, while the heat generated as a side effect by the lighting is not a surplus, but is efficiently used for heating.

As described above, the air condition is controlled by the air conditioning means 46, which are positioned in the air circulation' loop. Thus, an energy-efficient air conditioning is achieved. Further, if insufficient heat is received during the first time period or if insufficient heat is generated during the second time period, the air may be heated by the air conditioning means 46. If a surplus of heat is generated or received, the air may be cooled. Also, the air may be cooled for decreasing a humidity of the air. If the air is too cold in comparison with a predetermined desired temperature due to the cooling for dehydration, the air may be subsequently heated again. Likewise, if the air becomes to dry due to heating, water may be supplied to the air in order to increase the humidity. Using suitable controller system coupled to suitable sensors the air condition, e.g. temperature and humidity, may be controlled based on the determined conditions in comparison to desired conditions.

Due to the layered structure, in particular in the second controlled environment 16 in which the layers of grow environment areas 16A - 16F may be closely arranged, it may be difficult to inspect the plants in the respective plant containers 18. Therefore, inspection means such as cameras may be provided to inspect the plants. The images from the cameras may be inspected and assessed visually by a plant breeder. In an embodiment, the images are processed by a suitable processing unit, which may determine predetermined aspects of the plants in the images, for example. In an embodiment, an infrared radiation camera is used. If a plant is infected, its temperature, and therefore its surface temperature, is increased. So, even if the infection has not resulted in visible defects of the plants, using the infrared radiation camera, it may be determined that a plant or a number of plants may be infected and may be isolated. Such a system and method of determining an infection of a plant may also be used in any other method of plant breeding or the like.

In order to provide good circumstances for the plants to grow a hydration level of the soil, or any other substrate in which the roots of the plants are positioned, is to be controlled. Therefore, the plants are provided with a predetermined amount of water when necessary. The amount may be determined by determining a weight of the plant including the substrate or soil and comparing the determined weight with a predetermined desired weight. The actual weight may then be brought to the desired weight by providing water. In an embodiment, the determining of the weight and providing water is not performed per plant, but is performed per plant container. In such an embodiment, the plant container including the plants is weighed and an amount of water to be provided is determined by a comparison of the actual weight and a predetermined desired weight. Such a system and method of determining an amount of water to be supplied to a plant may also be used in any other method of plant breeding or the like.

The greenhouse 10 as illustrated in Fig. IA - IB may comprise a controller for controlling the operation of one or more controllable elements. In particular, the controller may control the air circulation means 44A - 44F and the air conditioning means 46. Further, the controller may comprise or may be coupled to the processing means for assessing an image of a camera. The controller may further be employed for controlling a position of each of the plant containers, provided that the plant containers are movably supported. In an embodiment, these operations may of course be controlled by a number of separate, possibly networked controllers. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention.

The terms "a" or "an", as used herein, are defined as one or more than one. The term number, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language) . The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

Claims

1. Method for growing plants in a controlled environment, a first plant being positioned in a first controlled environment and a second plant being positioned in a second controlled environment, the method comprising: during a first time period, providing a day-time lighting condition in the first controlled environment and a night-time lighting condition in the second controlled environment; during a second time period, providing the night-time lighting condition in the first controlled environment and the day-time lighting condition in the second controlled environment; and exchanging heat between the first controlled environment and the second controlled environment for controlling a temperature in the first controlled environment and a temperature in the second controlled environment; wherein the first time period and the second time period are alternated.

2. Method according to claim 1, wherein the first time period is a day-time period and the second time period is a night-time period and wherein the method comprises during day-time, receiving daylight in the first controlled environment and blocking daylight from entering the second controlled environment; and during night-time, generating a predetermined lighting condition in the second controlled environment.

3. Method according to claim 1 or 2, wherein the method comprises circulating air between the first and the second controlled environment for exchanging heat.

4. Method according to claim 3, wherein the air circulation is a forced air circulation.

5. Method according to claim 4, wherein the air circulation is a controlled forced air circulation, in particular at least one of an air velocity and an air amount per unit time being controlled.

6. Method according to claim 5, wherein at least one of the first and the second controlled environment is divided in a number of grow environment areas and wherein the forced air circulation is controlled per grow environment area.

7. Method according to any one of the preceding claims, wherein an air condition of the circulating air and/or an air condition of the air in the first controlled environment and/or an air condition of the air in the second controlled environment is controlled.

8. Method according to claim 7, wherein at least one of an air temperature and an air humidity is controlled.

9. Method according to any of the preceding claims, wherein the plants are positioned in a container, the method further comprising: determining a weight of a container holding a number of plants; determining from the determined weight a soil humidity of the soil on which the plants are growing; and supplying a predetermined amount of water to the plants based on the determined soil humidity.

10. Method according to any one of the preceding claims, the method further comprising: acquiring an infrared-radiation image of a plant; determining a surface temperature of the plant based on the infrared-radiation image; and determining a condition of the plant based on the surface temperature of the plant.

11. Method according to any one of the preceding claims, wherein a plant is positioned in a container, the container having a gas- transmissive base, the method comprising: generating an air circulation in a loop, wherein the loop runs from above the plant, alongside the container to below the container, through the base of the container, past the plant to above the plant.

12. Method according to claim 11, wherein the air circulation loop further runs through an air conditioning area for controlling a condition of the air.

13. Method for controlling watering of a plant, the method comprising: determining a weight of the plant and soil in which the plant is positioned; comparing the determined weight with a predetermined value; based on the comparison, supplying a predetermined amount of water to the plant and/or soil.

14. Method for determining a condition of a plant, the method comprising: acquiring an infrared-radiation image of the plant; determining a surface temperature of the plant based on the infrared image; determining the condition of the plant based on the surface temperature.

15. Construction for growing plants in a controlled environment, the construction comprising: a first controlled environment configured to provide a day-time lighting condition during a first time period and to provide a night-time lighting condition during a second time period; a second controlled environment configured to provide a night-time lighting condition during the first time period and to provide a day-time lighting condition during the second time period; wherein the first controlled environment and the second controlled environment are coupled such that heat is exchangeable between the first controlled environment and the second controlled environment.

16. Construction according to claim 15, wherein the construction comprises a greenhouse construction.

17. Construction according to claim 15 or 16, wherein the construction is configured for circulating air between the first and the second controlled environment for exchanging heat.

18. Construction according to claim 17, wherein the construction comprises air circulation means for forcing an air circulation between the first and the second controlled environment.

19. Construction according to claim 18, wherein the means for forcing an air circulation is a controllable means, in particular for controlling at least one of an air velocity and an air amount per unit time.

20. Construction according to claim 19, wherein at least one of the first and the second controlled environment is divided in a number of grow environment areas and wherein the forced air circulation is controllable per grow environment area.

21. Construction according to any one of the claims 15 - 20, wherein the construction further comprises a device for controlling a condition of the air in the first controlled environment and/or the second controlled environment and/or for controlling a condition of circulating air.

22. Construction according to claim 21, wherein at least one of an air temperature and an air humidity is controllable.

23. Construction according to any of the claims 15 - 22, wherein the construction further comprises a container for holding the plants, the construction further comprising: a weighing means for determining a weight of the container holding a number of plants; a processing means for determining from the determined weight a soil humidity of the soil on which the plants are growing; and a watering means for supplying a predetermined amount of water to the plants based on the determined soil humidity.

24. Construction according to any of the claims 15 - 23, wherein the construction further comprises : an infrared-radiation camera for acquiring an infrared-radiation image; and a processing means for determining a surface temperature of the plant based on the acquired infrared-radiation image.

25. Construction according to any of the claims 15 - 24, wherein the construction further comprises: a container for holding plants, the container having a gas- transmissive base; an airflow generating means for generating an airflow; and . means for guiding the airflow; wherein the container, airflow generating means, and the means for guiding the airflow are positioned such that an air circulation may be generated in a loop, wherein the loop runs from above a plant held in the container, alongside the container to below the container, through the base of the container, past the plant to above the plant.

26. Construction according to claim 25, wherein the air circulation loop further runs through an air conditioning area for controlling a condition of the air.