METHOD, DEVICE AND USE OF VENTILATION SYSTEM FOR GROWING PLANTS

Abstract

The invention relates to a ventilation system and method for promoting growth of a plant. The system comprises an air inlet provided at a first height from a defined floor level, an air outlet, fluidly connected to the inlet, an air moving device for moving air from the inlet to the outlet, and a plant growing surface, provided at a second height, being higher than the first height, for accommodating growing plants, wherein the air outlet is provided at a third height, being higher than the second height. The inventive concept is based on the inventors' realization that improved growing conditions can be provided by transporting CO.sub.2 from the bottom of a lower level in a greenhouse to a higher level.

Claims

1. Ventilation system for promoting growth of a plant, said system comprising, an air inlet provided at a first height from a defined floor level, an air outlet, fluidly connected to said inlet, an air moving device for moving air from said inlet to said outlet, and a plant growing surface, provided at a second height, being higher than said first height, for accommodating growing plants, wherein said air outlet is provided at a third height, being higher than said second height.

2. Ventilation system according to claim 1, further comprising a controller for controlling the air moving device.

3. Ventilation system according to claim 2, further comprising a light source arranged at a fourth height, being higher than said second height, wherein said controller is adapted to activate said air moving device upon activation of said light source.

4. Ventilation system according to claim 1, further comprising a CO.sub.2 input for increasing the CO.sub.2 level in the air to be supplied to the outlet, and a CO.sub.2 controller for controlling the CO.sub.2 input.

5. Ventilation system according to claim 4, further comprising a CO.sub.2 sensor for measuring CO.sub.2, said CO.sub.2 sensor being communicatively connected to the CO.sub.2 controller.

6. Ventilation system according to claim 5, wherein said sensor is adapted to measure CO.sub.2 at said second height.

7. Ventilation system according to claim 1, further comprising a plurality of inlets and/or outlets for covering a larger area of a greenhouse.

8. Use of a ventilation device according to claim 1, for promoting growth of plants in a greenhouse.

9. Use of a ventilation device according to claim 8, wherein said plant is a cannabis plant.

10. Method for promoting growth of a plant, the method comprising: drawing in air with an air inlet provided at a first height from a defined floor level, transporting said air with an air moving device to an air outlet, fluidly connected to said inlet, wherein said air outlet is provided at a third height, being higher than said first height, and feeding said air towards a plant growing surface provided at a second height between said first height and said third height.

11. Method according to claim 10 further comprising the step of controlling the air moving device with a controller.

12. Method according to claim 10, further comprising the steps of: measuring a first CO.sub.2 level, preferably at said second height, comparing said first CO.sub.2 level to a desired CO.sub.2 level, and adding a first CO.sub.2 injection to the air to be transported to said air outlet if the first measured level is below the desired level.

13. Method according to claim 12, wherein said method further comprises the steps of: measuring a second CO.sub.2 level, subsequent to the step of adding the first CO.sub.2 injection, and comparing said second CO.sub.2 level to said desired CO.sub.2 level, and adding a second CO.sub.2 injection to the air to be transported to said air outlet, if the second measured CO.sub.2 level is still below the desired CO.sub.2 level.

14. Method according to claim 15, wherein the first CO.sub.2 injection is performed during a time duration being different than a time duration during which the second CO.sub.2 injection is performed.

15. Method according to claim 15, wherein the first CO.sub.2 injection is performed during a time duration corresponding to an addition of CO.sub.2 that is estimated to bring the CO.sub.2 level closer to the desired CO.sub.2 level, but not all the way to the desired CO.sub.2 level, such as 60%, 80% or 90% of the difference between the measured CO.sub.2 level and the desired CO.sub.2 level.

16. Method according to claim 13, further comprising a step of waiting before conducting the step of measuring a second CO.sub.2 level, so as to let the air mix with the CO.sub.2 in the first CO.sub.2 injection.

17. Method according to claim 15, wherein the second step of adding the CO.sub.2 is conducted during a time duration calculated from: the difference between the second measured CO.sub.2 level and the desired CO.sub.2 level, the difference between the first and second measured CO.sub.2 level, and the duration of the first addition of CO.sub.2.

18. Method according to claim 11, wherein the step of feeding said air towards the plant growing surface generates an air flow for creating a movement of plants placed on the plant growing surface.

19. Method according to claim 10, wherein the desired CO.sub.2 level is dependent on the growth cycle of said plant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing exemplar embodiments of the present invention, wherein:

[0043] FIG. 1 illustrates a schematic side view of a greenhouse with a ventilation system according to some embodiments of the invention, and

[0044] FIG. 2 illustrates a flow-chart overview of a method according to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0045] In the following detailed description, some embodiments of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerous details are set forth to provide a more thorough understanding of the present invention, it will be apparent to one skilled in the art that the present invention may be practiced without these details. In other instances, well known constructions or functions are not described in detail, so as not to obscure the present invention.

[0046] FIG. 1 shows a system 1 according to the first aspect of the present invention, wherein the system 1 is arranged in a greenhouse 2. The greenhouse 2 may be any conventional greenhouse of any size and made of any conventional material. Here, the greenhouse 2 comprises an outer structure 3 built upon a foundation 4. Furthermore, the greenhouse 2 is here not part of the system 1. In some embodiments, the greenhouse 2, or any part of the greenhouse, may comprise an integrated system 1 as described.

[0047] The system 1 comprises an air ventilation unit 5. The air ventilation unit 5 comprising an air inlet 6 for drawing in air from a floor level FL. The air inlet 6 is arranged at an inlet level IL above the floor level FL. The air inlet 6 is further connected to an air moving device 7 for moving the air drawn in by the air inlet 6. The air is moved by the air moving device 7 through a pipe 8 and to an air outlet 9. As such, the air outlet 9 is fluidly connected to the air inlet 6. The air outlet 9 is arranged at an outlet level OL. The outlet level OL is arranged above the floor level FL and the inlet level IL. The air outlet 9 is furthermore adapted to feed the air back into the greenhouse 2 and towards a plant 13. The air could be directly fed in the direction of the plant 13. Alternatively, the air could be indirectly fed to the plant 13 e.g. be being fed in an upwards facing direction, with any redirecting means such as a ceiling 2 a of the greenhouse 2 or vent member (not shown), or a flange (not shown) arranged in the ceiling 2 for redirecting air flow, resulting in the air consequently moves towards the plant 13.

[0048] The system 1 further comprises a plant bed 10 comprising soil 11, such that a plant growing surface 12 is arranged at a plant level PL. A plant 13 is accommodated in the plant bed 10 such that it is planted at the plant level PL. The plant level PL is arranged above the floor level FL, but below the outlet level OL. The plant 13 is here shown to be a cannabis plant. In other embodiments the plant 13 may be any other type of plant. For example, the plant 13 may be any plant that is commonly grown in a greenhouse, such as a tomato plant, a cucumber plant etc. Furthermore, the present invention is not limited to any number of plants 13.

[0049] The system 1 further comprises a light source 14 arranged at a light source level LL. The light source 14 is adapted to provide light to the plant 13. The light source 14 may e.g. be a UV-lamp adapted to provide light at least within an interval of wavelengths that promote plant growth. Here, the light source level LL is arranged above the floor level FL, above the plant level PL but below the outlet level OL. Alternatively, the light source level LL is arranged above the outlet level OL.

[0050] Here, the floor level FL is a defined floor level, the inlet level IL is arranged at a first height, the plant level PL is arranged at a second height and the outlet level OL is arranged at a third height.

[0051] The system 1 further comprises a CO.sub.2 inlet 15 for providing CO.sub.2 to the atmosphere of the greenhouse 2. Here, the CO.sub.2 inlet is arranged close to the floor level FL, but it may be arranged at any height. However, placing the CO.sub.2 inlet close to the floor level FL means that the air at the floor level FL will have, when the CO.sub.2 inlet has added CO.sub.2, a higher concentration of CO.sub.2 than e.g. the air at the plant level PL. As such, when the CO.sub.2 inlet has added CO.sub.2 to the air at the floor level FL, such that the air at the floor level FL has a higher concentration of CO.sub.2, the air inlet 6 of the ventilation device 5 draws in air with a higher concentration of CO.sub.2 than if the CO.sub.2 inlet would not have added CO.sub.2.

[0052] The CO.sub.2 inlet 15 is further connected to a controller 16. The controller 16 is in turn here shown to be connected to the air moving device 6 and the light source 14. As such, the controller 16 is adapted to control the CO.sub.2 inlet, the air moving device 6 and the light source 14. Thus, a signal from the light source 14 may be received by the controller 16, whereupon the controller 16 activates or deactivates the air moving device 6. Alternatively, the controller 16 further comprises a photocell (not shown) adapted to receive light from the light source 14 such that it subsequently, upon receipt of the light, activates the air moving device 6. The controller 16 is further connected to a CO.sub.2 sensor 17 for measuring a CO.sub.2 level. Here, the CO.sub.2 sensor 17 is arranged close to the plant level PL. As such, the CO.sub.2 sensor 17 may provide the controller 16 with input data for controlling any other device in the system 1, such as the CO.sub.2 inlet 15.

[0053] FIG. 2 schematically describes the steps in a method for promoting growth of a plant. The method comprises the major steps, namely S1 drawing in air with an air inlet provided at a first height from a defined floor level, S2 transporting said air with an air moving device to an air outlet, fluidly connected to said inlet. Moreover the air outlet is provided at a third height, being higher than said first height, and thirdly S3 feeding said air towards a plant growing surface provided at a second height between said first height and said third height. In some embodiments the step of feeding the air towards the plant growing surface generates an air flow for creating a movement of plants placed on the plant growing surface. This may be achieved by directing the outlet towards the plant growing surface, or e.g. by arranging an air guide element to guide the air towards the plant growing surface.

[0054] Although FIG. 2 illustrates that the optional steps S4-S9 as being connected to step 1 of drawing air, it should be understood that the method steps S4-S9 may well be performed in parallel with the steps S1-S3. In fact, it is possible the that optional steps S4-S9 are performed independently of steps S1-S3.

[0055] FIG. 2 further shows the optional step of measuring S4 a CO.sub.2 level with a CO.sub.2 sensor 17, preferably at the second height, e.g. the plant level PL. The step of S4 measuring is here a first measurement, such that the measured value M1 is a first determined value. After the first measuring S4 of a CO.sub.2 level, the step of comparing S5 it to a desired level X is performed. The desired level X is e.g. provided as an input value into a controller 16 by an operator of a system according to the first aspect of the present invention. If M1<X, i.e. if the first measured value M1 is below the desired value X, a first CO.sub.2 injection is added during the step of adding S6 a first CO.sub.2 injection to the air to be drawn into the air inlet 6. If M1>X or if M1=X, i.e. if the first measured value M1 is larger than or equal to the desired value X, no CO.sub.2 is added.

[0056] After the step of adding S6 CO.sub.2 a second step of measuring S7 a CO.sub.2 level is performed. Preferably, before conducting this second step of measuring S7 a waiting period should occur so as to let the air mix with the CO.sub.2 that was injected in the first injection. The second measuring S7 provides a second measured value M2. Subsequently, the step of comparing S8 the second value M2 to the desired level X is performed. The desired level X may be the same in both steps of (S5, S8) comparing, but may alternatively be different. If M2<X, i.e. if the second measured value M2 is below the desired value X, a second CO.sub.2 injection is added during the step of adding S9 a second CO.sub.2 injection to the air to be drawn into the air inlet 6. If M2>X or if M2=X, i.e. if the second measured value M2 is larger than or equal to the desired value X, no CO.sub.2 is added. It is to be understood that the method described is not limited to two respective steps of measuring, comparing and (optionally) adding CO.sub.2, but may comprise further instances of any of these steps. As one example, if the measured level is lower than the desired level the measuring may be initiated again an infinite number of times.

[0057] In some embodiments, the step of adding the CO.sub.2 may be dependent on the difference between the measured value and the desired value. E.g. if the concentration of CO.sub.2 level in the air is only 50% of the desired value the CO.sub.2 injection may have a duration of a first time duration, such as 20 seconds. Whereas if the CO.sub.2 level in the air is about 80% of the desired value the CO.sub.2 injection may have a duration of a second (shorter) time duration, such as 5 seconds. Thus, the time duration of the injection may be related to the difference between the measured value and the desired value.

[0058] In one embodiment, the first step of adding the CO.sub.2 is conducted during a time duration relating to an amount of CO.sub.2 corresponding to about 80% of difference between the measured CO.sub.2 level and the desired CO.sub.2 level. Hereby, the risk of adding too much CO.sub.2 is reduced.

[0059] In one embodiment, the second step of adding the CO.sub.2 is conducted during a time duration relating to both the difference between the measured CO.sub.2 level and the desired CO.sub.2 level and taking into consideration the actual increase of CO.sub.2 concentration between the two most recent measurements and the most recent addition of CO.sub.2 level. Hereby, the amount of CO.sub.2 may be calculated based on previous learnings. As an example, the first measurement M1 corresponded to 30% of the desired CO.sub.2 level X, and the first addition of CO.sub.2 was conducted for time duration of 30 seconds. Thereafter the second measurement M2 shows a CO.sub.2 level corresponding to 90% of the desired CO.sub.2 level X. Then, the first addition that had a duration of 30 seconds resulted in an increase from 30% to 90% of the desired CO.sub.2 level X, then the second addition could have a duration of 5 seconds to top up the CO.sub.2 level to reach about 100% of the desired CO.sub.2 level.

[0060] In some embodiments, the desired CO.sub.2 level is dependent on the growth cycle of the plant or plants to which CO.sub.2 is to be supplied. E.g. the desired level may be higher during some developments of the plant and lower during other development stages.

[0061] The invention has now been described with reference to specific embodiments. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting to the claim. The word “comprising” does not exclude the presence of other elements or steps than those listed in the claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.