Greenhouse

Abstract

A greenhouse having a roof, a floor, two end walls, and two side wall. Along one of the end or side walls an elongated mixing space is present next to an elongated space for conditioned air. The mixing space is fluidly connected to the exterior of the greenhouse and fluidly connected to a growing space by means of one or more openings. The mixing space and the space for conditioned air are fluidly connected via one or more water pads and via a parallel bypass flow path. The growing space comprises a multitude of parallel ventilation conduits, wherein each conduit has an air inlet that is fluidly connected to the space for conditioned air.

Claims

1. A greenhouse comprising: a roof; a floor; two end walls; and two side walls, wherein along one of the end walls or side walls an elongated mixing space is positioned next to an elongated space for conditioned air, wherein the mixing space and the space for conditioned air are separated from a growing space that is present within the greenhouse, wherein the mixing space is fluidly connected to the exterior of the greenhouse by openings for ambient air and fluidly connected to the growing space by one or more openings, wherein the mixing space and the space for conditioned air are fluidly connected via one or more water pads and via a parallel air flow path, wherein the water pads are positioned parallel to the parallel flow path, wherein the growing space comprises multitude of parallel ventilation conduits, and wherein each conduit has an air inlet provided with a ventilator and which air inlet is fluidly connected to the space for conditioned air.

2. A greenhouse according to claim 1, wherein the parallel air flow path comprises one or more indirect heating units.

3. A greenhouse according to claim 1, wherein the parallel air flow path is provided with air displacement means.

4. A greenhouse according to claim 1, wherein the openings to the exterior of the greenhouse for ambient air are semi-closable openings designed such that at least one volume part of ambient air enters the mixing space per 20 volume parts of air entering the mixing space from the growing section.

5. A greenhouse according to claim 1, wherein the openings to the growing section of the greenhouse are semi-closable openings designed such that at least one volume part of air from the growing space enters the mixing space per 20 volume parts of ambient air entering the mixing space.

6. A greenhouse according to claim 1, wherein the openings to the exterior of the greenhouse for ambient air of the mixing space are openings in the roof.

7. A greenhouse according to claim 1, wherein the mixing space and the space for conditioned air are each a single space.

8. A greenhouse according to claim 1, wherein the mixing space is defined by the roof, an end wall or a side wall, a substantially vertical partition wall spaced apart from the end wall or side wall and that runs substantially parallel to the end wall or side wall, and the floor or a substantially horizontal elevated partition floor spaced apart from the floor.

9. A greenhouse according to claim 8, wherein the space for conditioned air is defined by the floor or substantially horizontal elevated partition floor, the end wall or side wall, and a substantially vertical partition wall spaced apart from the end wall or side wall.

10. A greenhouse according to claim 9, wherein the elevated partition floor is spaced apart from the floor for at least two meters and the vertical partition wall of the space for conditioned air is provided with a number of emergency doors.

11. A greenhouse according to claim 9, wherein the air inlets of the multitude of parallel ventilation conduits are fluidly connected to the vertical partition wall of the space for conditioned air by a ventilator.

12. A greenhouse according to claim 7, wherein the one or more water pads are comprised of a vertical wetted screen positioned on the floor or on the partition floor and run along more than 80% of the length of the elongated mixing space, and wherein the vertical wetted screen has an inlet side for air fluidly connected to the mixing space and an outlet side for air fluidly connected to the space for conditioned air.

13. A greenhouse according to claim 12, wherein a horizontal roof part is connected to the upper end of the vertical wetted screen or to an upper end of a wall comprising the vertical wetted screen, the horizontal roof part extending to the vertical partition of the mixing space, and wherein the roof part is comprised of the one or more indirect heating units having an inlet side for air fluidly connected to the mixing space and an outlet side for air fluidly connected to the space for conditioned air.

14. A process to control the temperature and/or humidity in a greenhouse comprising a growing space and a separate mixing space, the process comprising the following steps: (a) collecting ambient air and air from the growing space in the separate mixing space to obtain feed air; (b) directly contacting part of the feed air with liquid water to adiabatically cool the feed air to obtain a humid air, wherein another part of the feed air is not contacting directly with liquid water to obtain bypass air; and (c) mixing the humid air and the bypass air to obtain a conditioned air, and discharging the conditioned air to the growing space.

15. A process according to claim 14, wherein the part of the feed air the is not contacted directly with liquid water is increased in temperature before performing step (c).

16. A process according to claim 14, wherein the separate mixing space is a continuous space running along an end wall or a side wall of the greenhouse, which is rectangular.

17. A process according to claim 16, wherein the rectangular greenhouse has a roof, a floor, two end walls, and two side walls, wherein the mixing space is defined by part of the roof of the greenhouse, an end wall or a side wall, a vertical partition wall spaced apart from the end wall or side wall and running substantially parallel to the end wall or side wall, and the floor or a substantially horizontal and elevated partition floor spaced apart from the floor, wherein the ambient air enters the mixing space via one or more openings in the end wall or side wall and/or in the roof, and wherein the air from the growing space enters the mixing space via one or more openings in the partition wall.

18. A process according to claim 17, wherein the ambient air enters the mixing space via one or more openings in the roof.

19. A process according to claim 17, wherein the greenhouse comprises a space for conditioned air below the floor or substantially horizontal and elevated partition floor, and wherein in step (c) the conditioned air is discharged to the growing space via a multitude of parallel ventilation conduits in the growing space, the ventilation conduits having an inlet for conditioned air that is fluidly connected to the space for conditioned air.

20. A greenhouse comprising: a roof; a floor; two end walls; two side walls; and a first elongated mixing space and a second elongated mixing space that separate a first growing space and a second growing space that are present within the greenhouse, wherein the first elongated mixing space is fluidly connected to the exterior of the greenhouse by openings for ambient air in the roof and fluidly connected to the first growing space by one or more openings, wherein the second elongated mixing space is fluidly connected to the exterior of the greenhouse by openings for ambient air in the roof and fluidly connected to the second growing space by one or more openings, wherein the first growing space comprises a multitude of parallel ventilation conduits, each conduit having an air inlet that is fluidly connected to the first mixing space, and wherein the second growing space comprises a multitude of parallel ventilation conduits, each conduit having an air inlet that is fluidly connected to the first mixing space.

21. A greenhouse according to claim 20, wherein the first and second elongated mixing spaces are each positioned next to an elongated first and second space for conditioned air, wherein the first and second elongated mixing spaces and the space for conditioned air are separated from the first and second growing spaces that are present within the greenhouse, wherein the first and second elongated mixing spaces and the space for conditioned air are fluidly connected via one or more water pads and via a parallel air flow path, wherein the water pads are positioned parallel to the parallel flow path, wherein each of the multitude of parallel ventilation conduits of the first growing space have an inlet fluidly connected to the first space for conditioned air, and wherein each of the multitude of parallel ventilation conduits of the second growing space have an inlet fluidly connected to the second space for conditioned air.

22. A greenhouse according to claim 20, wherein the first and second elongated mixing spaces run parallel from end wall to the opposite end wall.

23. A greenhouse according to claim 21, wherein the first and second elongated mixing spaces run parallel from end wall to the opposite end wall.

24. A greenhouse according to claim 22, wherein the first and second elongated mixing spaces share a common wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Embodiments of the invention will be illustrated by the following figures.

[0041] FIG. 1 shows a cross-sectional view of a greenhouse according to an embodiment of the invention.

[0042] FIG. 2 shows an embodiment of the greenhouse where a mixing space is present along an entire end wall.

[0043] FIG. 3 shows a variant of the greenhouse of FIG. 1.

[0044] FIG. 4 shows a variant of the greenhouse of FIG. 3.

[0045] FIG. 5 shows a three-dimensional view of the greenhouse of FIG. 3.

[0046] FIG. 6 shows a greenhouse according to an embodiment of the invention.

[0047] FIG. 7 shows a greenhouse according to an embodiment of the invention.

[0048] FIG. 8 shows a cross-sectional view of greenhouse shown in FIG. 7.

DETAILED DESCRIPTION

[0049] FIG. 1 shows a cross-sectional view of a greenhouse (1) having a saddle roof (2) and a floor (3). An elongated mixing space (6) is present along the entire side wall (5). The mixing space (6) is fluidly connected to the exterior (10) of the greenhouse by means of closable openings (9) for ambient air as present in the saddle roof (2). These openings (9) may be a single elongated opening running substantially along the entire length of the elongated mixing space (6) and saddle roof (2) as shown in FIG. 5. An elongated space (7) for conditioned air is shown positioned at the lower end of a partition wall (16). At the upper end part of this partition wall (16) one or more closable openings (11) are shown which openings (11) allow air to flow from a growing space (8). The mixing space (6) and the space (7) for conditioned air is separated from a growing space (8). The mixing space (6) and the space (7) for conditioned air are fluidly connected via one or more vertical screens (12) as the water pads and via one or more indirect heating units (15) as present in a parallel air flow path (B). The air from the mixing space (6) can flow to the space for conditioned air (7) via two parallel flow paths (A) and (B) as shown. The humid air flowing in air flow path (A) and the heated air in parallel air flow path (B) are mixed in the space (7) and the resulting conditioned air is distributed in the growing section (8) via a multitude of parallel ventilation conduits (13) as schematically represented by arrow C. Conditioned air enters the ventilation conduit at an inlet (14). At this inlet (14) a ventilator (20) is present.

[0050] The mixing space (6) of FIG. 1 is bounded by part of the roof (2), the side wall (5), part of the floor (3), partition wall (16) and part of two facing end walls (4) (as shown in FIG. 5). A horizontal roof part (26) is connected to the upper end (24) of the vertical wetted screen (12). The roof part (26) is connected at its other elongated end to the partition wall (16). The roof part (26) is comprised of the one or more indirect heating units (15) having an inlet side for air (27) fluidly connected to the mixing space (6) and an outlet side for air (28) fluidly connected to the space (7) for conditioned air.

[0051] FIG. 2 shows an embodiment of the greenhouse where the mixing space (6) is present along the entire end wall (4) comparable to the greenhouse of WO2008/002686. The other references have the same meaning as in FIG. 1 except for closable windows (9). These windows (9) in FIG. 2 will be separate windows present in the row of saddle roofs (2).

[0052] FIG. 3 is a variant of the greenhouse of FIG. 1. The difference is that the mixing space (6) is defined by the roof (2), a side wall (5), a substantial vertical partition wall (16) spaced apart from the side wall (5) and running substantially parallel to the side wall (5) and a substantially horizontal elevated partition floor (17) spaced apart from the floor (3) by at least 2 meters. The space (7) for conditioned air is defined by the substantially horizontal and elevated partition floor (17), the side wall (5) and a substantial vertical partition wall (18) spaced apart from the side wall (5). The vertical partition wall (18) is provided with a number of emergency doors (19) as part of an emergency escape route indicated by arrow D from the growing area to the space (7) for conditioned air. Door (19) may run all the way to the floor for easy access. Because the screens (12) and heating units (15) are positioned more elevated a free from obstacles emergency route for personnel from the growing section to the space for conditioned air is so provided. The upper side of partition floor (17) is slightly tilted such that any condensed water will flow towards the lower end of the screens (12) where it may be collected in a gutter to be discharged with the water running through the screens.

[0053] FIG. 4 is a variant of the greenhouse of FIG. 3 except that the mixing space (6) runs along the end wall (4).

[0054] FIG. 5 is a three-dimensional view of the greenhouse of FIG. 3. The dimensions are not entirely at scale. For example the width of a single saddle roof part, i.e., the width of the mixing space (6) may be about 4.5 m while the length of a single ventilation conduit (13) may be up to 110 meters as present below 25 saddle roof parts (29). The closable opening (9) and the closable opening (11) may run along the entire length of the side wall (5). Each passage between neighbouring ventilation conduits (13) may be provided with an emergency door (19). In this way workers as present in these passages have access to an emergency door.

[0055] FIG. 6 shows a greenhouse (30) having a roof (2), a floor (3), two end walls (4) and two side walls (5), and a first and a second elongated mixing space (6a, 6b) which first and second elongated mixing space (6a,6b) separates a first and a second growing space (8a, 8b) as present within the greenhouse (30). First and second elongated mixing spaces (6a,6b) run parallel from end wall (4) to the opposite end wall (4) and suitably share a common wall (32) as shown. The first elongated mixing space (6a) is fluidly connected to the exterior (10) of the greenhouse by means of openings (9a) for ambient air in the roof (2) and fluidly connected to the first growing space by means of one or more openings (11a). The second elongated mixing space (6b) is fluidly connected to the exterior (10) of the greenhouse by means of openings (9b) for ambient air in the roof (2) and fluidly connected to the second growing space by means of one or more openings (11b). The first growing space (8a) comprises a multitude of parallel ventilation conduits (13a) and wherein each conduit (13a) has an air inlet (14a) that is fluidly connected to the first mixing space (6a).The second growing space (8b) comprises a multitude of parallel ventilation conduits (13b), wherein each conduit (13b) has an air inlet (14b) that is fluidly connected to the first mixing space (6b). The elongated mixing spaces (6a,6b) have the configuration of FIG. 3 and for clarity reasons only the partition floor (17) and the space (7) for conditioned air is shown. In FIG. 6 the first and second elongated mixing spaces (6a,6b) share a common wall (32) as shown and as preferred. Alternatively between the two mixings spaces of the multi-compartmented greenhouse (30) a small corridor for maintenance and accessing of the mixing spaces (6a,6b) and/or the space (7) for conditioned air may be present.

[0056] FIG. 7 shows a greenhouse (33) which is similar to greenhouse (30) of FIG. 6 except in that no parallel air flow path (B) is present. In this greenhouse all the ambient air and air from growing spaces (8a,8b) flows via one or more vertical screens (12a,12b) functioning as water pads. The space downstream these vertical screens (12a,12b) may be one continuous space for every first and second elongated mixing space (6a,6b) and/or may be separate spaces as illustrated in FIG. 8.

[0057] FIG. 8 shows a cross-sectional view AA′ of FIG. 7. For first elongated mixing space (6a) the space downstream vertical screen (12a) are separate spaces (34a) per conduit (13a). For second elongated mixing space (6b) the space downstream vertical screen (12b) is one continuous space (34b) fluidly connected to all conduits (13b).

[0058] An advantage of a combined greenhouse according to FIG. 6, 7, or 8 is that unit operations can be closer together as compared to when two separately spaced greenhouses would be used. Further less area is required for the same area of growing space for the combined greenhouse because no space is required at the sides or ends for intake of ambient air.

EXAMPLE 1

[0059] A greenhouse according to FIGS. 3 and 5 is simulated wherein ambient air (10) of 35 C and a relative humidity of 40% is used. The air in the growing section (8) has a temperature of 32° C. and has a relative humidity (RH) of 85%. Further properties are listed in Table 1. The control object in this example is to reduce the temperature of the air in the growing section (8) and not increasing the relative humidity by obtaining conditioned air in space (7) and providing this conditioned air via the ventilating conduits (13) into the growing section.

[0060] The conditioned air in (7) is obtained by first mixing 95 volume parts of the ambient air (10) with 5 volume parts in mixing space (6) to obtain a feed air having a temperature of 34.8° C. and a relative humidity of 42.1%. Of this feed air 84 vol % is contacted with liquid water in the water pads (12) to obtain humid air having a temperature of 25.4° C. and a relative humidity of 90.2%. The remaining 16 vol. % of the feed air bypasses or otherwise circumvents the water pads (12) via parallel air flow path (B) (as in FIG. 1) and is mixed with the humid air to obtain conditioned air having a temperature of 27° C. and a relative humidity of 79.5%. In this example the air in parallel air flow path (B) is not heated. The conditioned air has a lower temperature than the air in the growing section and has a lower relative humidity and is thus suited to reduce the temperature in the growing section (8) when supplied to said growing section via ventilation conduits (13) and decreasing the humidity in the growing section (8).

EXAMPLE 2

[0061] Example 1 is repeated except that the air in parallel air flow path (B) is heated increasing its enthalpy by about 0.1 kJ/kg. The temperature of the resulting conditioned air in space (7) is 27.1° C. and the relative humidity (RH) is 78.9%. As in Example 1 the conditioned air has a lower temperature than the air in the growing section and has an even lower relative humidity and is thus suited to reduce the temperature in the growing section (8) when supplied to said growing section via ventilation conduits (13) and decreasing the humidity in the growing section (8).

Comparative Experiment

[0062] This calculated experiment will show how the same ambient air of examples 1 and 2 is used to cool the air in the growing section having the same starting conditions as in Examples 1 and 2 in a state-of-the-art greenhouse. In this example the ambient air is first reduced in temperature by direct contacting with liquid water in water pads to obtain a humid air having a temperature of 25.1° C. and a relative humidity (RH) of 89.8%. In order to reduce the humidity to a value below the humidity in the growing section this humid air is heated to 27.1° C. (equal to Example 2) and having a relative humidity of 80%. The amount of energy required for this heating step is about 2 kJ/kg.

[0063] Thus in the prior art greenhouse significantly more energy is required to obtain suitable air for supplying to the growing section in order to cool the air in the growing section of the prior art greenhouse. Further the humidity of this air is even higher than in Example 2. This comparison shows that the greenhouse according to an embodiment of the invention and the process provides a more energy efficient process and lower relative humidity air for conditioning the interior of the growing space of a greenhouse.

TABLE-US-00001 TABLE 1 Comparative Example 1 Example 2 experiment Ambient air (° C.) 35.0 35.0 35.0 Ambient air RH (%) 40 40 40 Enthalpy ambient air (kJ/kg) 71.44 71.44 71.44 Starting air temperature in 32 32 32 growing section (° C.) Starting RH in growing 85 85 85 section (%) Starting enthalpy in growing 98.34 98.34 98.34 section (kJ/kg) Temperature of conditioned 27 27.1 27.1 air as feed for ventilating conduits (° C.) RH of conditioned air as feed 79.5 78.9 80 for ventilating conduits (%) Enthalpy of conditioned air 72.74 72.86 73.49 as feed for ventilating conduits (kJ/kg)