GREENHOUSE COMPRISING A CLIMATE CONTROL SYSTEM

Abstract

It is disclosed a ventilator (9A, 9) comprises a housing (20) having opposite first (21) and second ends (22) and an axial rotor (23) arranged in a ventilator flow path (23A), wherein the ventilator flow path (23A) has an inlet at the first end (21) of the housing (20) and an outlet (22A) at the second end of the housing (20) and wherein an additional flow path (25) is present comprising one or more sensors and which additional flow path (25) fluidly connects an opening (16, 24) in the housing (20) with the ventilator flow path (23A) for drawing in air due to a venturi effect via the additional flow path (25) towards the ventilator flow path (23A), wherein the sensors are temperature and/or humidity sensors.

Claims

1. A ventilator comprising a housing having opposite first and second ends and an axial rotor arranged in a ventilator flow path, wherein the ventilator flow path has an inlet at the first end of the housing and an outlet at the second end of the housing and wherein an additional flow path is present comprising one or more temperature and/or humidity sensors and which additional flow path fluidly connects an opening in the housing with the ventilator flow path for drawing in air due to a venturi effect via the additional flow path towards the ventilator flow path-.

2. A greenhouse comprising a climate control system and a roof, walls and a floor defining an interior greenhouse space, said greenhouse space comprising an upper space and a lower space as present below the upper space, wherein the roof is provided with closable openings, wherein the climate control system comprises a grid of control units and a central controller, wherein a control unit comprises an air flow path from the upper space to the lower space, an in air displacement controllable ventilator according to claim 1 for displacement of air from the upper space to the lower space via the air flow path and present in the lower space of the greenhouse and wherein the temperature sensor and/or a humidity sensor are suited to provide a measured temperature value and/or a measured humidity value, and wherein the central controller is programmed to individually adapt the air displacement of the ventilator of each control unit based on the measured temperature values and/or a measured humidity values.

3. A greenhouse according to claim 2, wherein the central controller is programmed to individually adapt the air displacement of the ventilator of a single control unit using the temperature value and/or humidity value as measured by the control unit and the one or more temperature values and/or one or more humidity values as measured by one or more other control units of the grid.

4. A greenhouse according to claim 3, wherein the central controller is programmed to individually increase the air displacement of the ventilator of a single control unit when the temperature value as measured by the control unit is higher than a calculated value based on the temperature values as measured by the other control units of the grid.

5. A greenhouse according to claim 3, wherein the central controller is programmed to individually increase the air displacement of the ventilator of a single control unit when the humidity value as measured by the control unit is higher than a calculated value based on the humidity values as measured by the other control units of the grid.

6. A greenhouse according to claim 2, wherein a control unit comprises a temperature sensor and a humidity sensor and wherein the central controller is programmed to individually adapt the air displacement of the ventilator of a single control unit when the measured temperature value and/or measured humidity value as measured by the temperature and humidity sensor of this control unit or a parameter based on at least both the measured temperature and the measured humidity values of this control unit is above or below a desired value based on temperature and humidity values as measured by the other control units of the grid.

7. A greenhouse according to claim 2, wherein the floor has a floor area and wherein per 2 to 200 m.sup.2 of floor area a control unit is present.

8. A greenhouse according to claim 7, wherein per 5 to 150 m.sup.2 of floor area a control unit is present.

9. A greenhouse according to claim 8, wherein per 12 to 100 m.sup.2 of floor area a control unit is present.

10. A greenhouse according to claim 2, wherein the roof is a saddle roof or arched roof wherein the roof is supported by trusses and wherein the trusses are supported by hollow columns having an hollow internal space and wherein one or more removable screens are present between the trusses, whereby the removable screens divide the interior greenhouse space into the upper and the lower space.

11. A greenhouse according to claim 10, wherein the air flow path from the upper space to the lower space runs via the hollow inner space of the columns.

12. A greenhouse according to claim 11, wherein the inlet at the first end of the in air displacement controllable ventilator is connected to the hollow inner space of the column in the lower space of the greenhouse.

13. A greenhouse according to claim 12, wherein a second flow path runs via the hollow inner space of the column from an opening in the column at a lower position below the ventilator to the ventilator and wherein a valve is present to direct air from the upper space of the greenhouse to the ventilator via the first flow path and/or direct air from the lower position to the ventilator.

14. A method to control the climate in a greenhouse interior space comprising an upper space positioned above a lower space by (i) measuring the local temperature and/or local humidity at numerous different local positions in the lower space resulting in numerous local measured temperature and/or humidity values, (ii) displacing air from the upper space to the lower space wherein the volume of air which is displaced at one local position is based on the measured temperature value and/or a measured humidity value at said local position.

15. A method according to claim 14, wherein the volume of air which is displaced at one local position is based on the measured temperature value and/or a measured humidity value at said local position and based on the measured temperature value and/or a measured humidity value of the remaining local positions.

16. A method according to claim 15, wherein in step the temperature and humidity is measured resulting in numerous local measured temperature and humidity values and wherein in the volume of air which is displaced at one local position is based on when the measured temperature value and/or measured humidity value at said local position is above or below a desired value based on temperature and humidity values as measured by the other control units of the grid.

17. A method according to claim 16, wherein the volume of air which is displaced at one local position is increased when the measured temperature value at said local position is higher than a calculated value based on the temperature values as measured by the other control units of the grid.

18. A method according to claim 14, wherein steps (i) and (ii) are performed at numerous local positions simultaneously in the greenhouse interior space, wherein the greenhouse interior space has a projected floor area and wherein per 2 to 200 m.sup.2 of floor area a local position is present.

19. A method according to claim 18, wherein per 5 to 150 m.sup.2 of floor area a local position is present.

20. A method according to claim 19, wherein per 12 to 100 m.sup.2 of floor area a local position is present.

21. A method according to claim 14 as performed in a greenhouse comprising a climate control system and a roof, walls and a floor defining an interior greenhouse space, said greenhouse space comprising an upper space and a lower space as present below the upper space, wherein the roof is provided with closable openings, wherein the climate control system comprises a grid of control units and a central controller, wherein a control unit comprises an air flow path from the upper space to the lower space, an in air displacement controllable ventilator for displacement of air from the upper space to the lower space via the air flow path and present in the lower space of the greenhouse and wherein the temperature sensor and/or a humidity sensor are suited to provide a measured temperature value and/or a measured humidity value, and wherein the central controller is programmed to individually adapt the air displacement of the ventilator of each control unit based on the measured temperature values and/or a measured humidity values.

Description

[0039] The invention shall be illustrated by the following FIGS. 1-12.

[0040] FIG. 1 shows a 3-dimensional view of part of a greenhouse (1) according to the invention provided with a climate control system (2) and a saddle roof (4), walls (5) and a floor (not shown) defining an interior greenhouse space (6). The interior greenhouse space (6) comprising an upper space (12) and a lower space (11) as present below the upper space (12). The roof (4) is provided with closable windows (7). This figure shows four hollow columns (8) of which two are provided with a in air displacement controllable ventilator (9) for displacement of air from the upper space (12) to the lower space (11) via the air flow path (13) which runs via the hollow column (8). The ventilators (9) are part of a grid of control units (10) as part of the climate control system (2). The climate control system (2) is further comprised of a central controller (34) (see FIG. 6). Further trusses (15) are shown. Hollow columns (8) are further provided with openings (16) at their lower end and a second flow path (17) runs via the hollow inner space of the column (8) from this opening (16) at a lower position below the ventilator (9) to the ventilator (9).

[0041] FIG. 2 shows a detail of FIG. 1 showing a hollow column (8) provided with a ventilator (9) and the air flow path (13). The column supports trusses (15). Between trusses (15) a substantial horizontal removable screen (18) is present. At the top end of the column (8) openings (19) are shown for intake of air from the upper space (12).

[0042] FIG. 3 shows a detail of FIG. 2. A ventilator (9) is shown attached to a hollow column (8) having a hollow inner space (8a). The ventilator (9) has a housing (20) having opposite first (21) and second ends (22) and an axial rotor (23) arranged in a ventilator flow path (23a) between an inlet (21a) and an outlet (22a). The outlet (22a) is fluidly connected to the inner space (1a) of greenhouse (1). An opening (24) in the housing (20) is a gas inlet opening (24) of the additional flow path (25) further shown in FIGS. 4 and 5.

[0043] FIG. 4 shows a cross-sectional view of the ventilator and column shown in FIG. 3. In this Figure the additional flow path (25) and temperature sensor (26) is shown. This temperature sensor measures the temperature of the air drawn in via opening (24) and flowing through additional flow path (25). In this way the temperature is measured of the air in the lower space in the vicinity of the ventilator (9). In order to continuously measure this temperature it is required that the axial rotor (23) displaces a minimum amount of air from the hollow column (8) to the first end (21). In this way air will be drawn in due to the venturi effect caused by the U-bend (27) in the additional flow path. Also a temperature sensor (28) is shown to measure the temperature in the air flow path (13) of the air drawn in from the upper space (12) to be discharged via ventilator (9) into the lower space (11).

[0044] FIG. 5 shown a variant of the ventilator (9) of FIG. 4. A ventilator (9a) is shown provided with a valve (29) which can influence the amount of air drawn in from the upper space (12) via air flow (13) or via second air flow path (17) from a position below the ventilator via openings (16) as shown in FIG. 1 via the hollow column to the ventilator (9a). This valve (29) may block air flow (13) or may block second air flow path (17) or may allow both air flows to flow when the axial rotor (23) of ventilator (9) is in operation. A further temperature sensor (30) is present to measure the temperature of the second air flow path (17). Such a temperature sensor (30), which may also be a humidity sensor is present in the second flow path suited to provide a measured temperature value and/or a measured humidity value for air in the second flow path. The measured values provide information on the temperature and/or humidity values of the air as displaced locally from the a position below the ventilator. This information may be used to adapt the required local air displacement by the control unit and it is found that the local conditions can be brought to the same value in a quicker way. Without such an additional measurement in the second flow path the invention also works but it may take longer to reach the desired local temperature and/or humidity conditions or desired parameter or property based on at least both the measured temperature and the measured humidity values of this control unit.

[0045] The invention shall be illustrated by the following non-limiting examples.

EXAMPLE 1

[0046] A greenhouse of FIG. 1 having a total area of 600 m.sup.2 was provided with 20 control units (10) resulting in one unit (10) every 30 m.sup.2 of greenhouse floor (3) area This layout is schematically shown in FIGS. 6 and 7. FIG. 6 shown the floor plan having two rows (30,31) of 5 columns (8). Every column (8) is provided with a pair of ventilators (9) of FIG. 4 which discharge air from the upper space (12) into opposite directions as indicated by arrows (32) in FIGS. 6 and 7. The control unit (10) was provided with a temperature sensor (28) to measure the temperature at an elevation of 4 m above the floor area (3). The greenhouse had closed screens (18) at an elevation of 5.5 m dividing the greenhouse in a lower space (11) and an upper space (12). In the lower space a cultivation (33) of various crops was present. The upper space was further defined by a saddle roof (4) with open windows (7) at the south-west and north-east side.

[0047] In this first experiment the air displacement of the ventilator (9) is manually increased according to the settings shown in FIG. 8. The temperatures were measured during a 1 hour period by the different units and FIGS. 9 and 10 presents the results. FIG. 9 shows the temperature variation in the greenhouse between 10 o'clock and 11.15 o'clock in the morning wherein each line represents the measured temperature in the lower space by one control unit. FIG. 10 illustrates heat maps of the greenhouse of this example at 10:15 at 10:45 and at 11:15. In this heat map the local temperatures are shown for the 20 control units shown in FIG. 6.

EXAMPLE 2

[0048] In a second experiment the ventilators of all the units operated at the same air displacement from upper space to lower space. The temperatures were measured during a 24 hour period by the different units and the results are presented in FIG. 11. Each line represents the temperature measured by a single control unit.

EXAMPLE 3

[0049] In a third experiment a controller (34) was used which controller (34) was programmed to individually increase the air displacement of the ventilator (9) of a control unit (10) when the temperature as measured by the temperature sensor (26) of the local control unit (10) is above a set temperature. Wherein the set temperature is the lowest value of all measured temperature values measured by all control units. The temperatures were measured during a 24 hour period by the different units and the results are presented in FIG. 12. Each line represents the temperature measured by a single control unit.

[0050] When comparing FIG. 11 with FIG. 12 it is clear that when the controller (34) was used the individual lines are closer together than when no controller is used. When the lines are closer together a more homogenic temperature in the lower space (11) is indicated which is advantageous for the growth of the different crop cultivations.