NL2027776B1

NL2027776B1 - Air treatment system for a green house

Info

Publication number: NL2027776B1
Application number: NL2027776A
Authority: NL
Inventors: Willem De Rijke Leendert; Middelburg Freek; Adrianus Hendrikus Maria Van Der Sande Johannes; Adrianus Van Den Berg Ronald; Van Nieuwenhuijzen Arjan; Vermeulen Pepijn
Original assignee: Belua Beheer B V
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2022-09-29

Abstract

The invention relates to a greenhouse (25,90) comprising walls (33,43,93,94,95,96) and a roof structure (41,42) deﬁning an interior space with a growing section (26,91) for growing crop and an airtreatment section (29,92). A number of airtreatment modules (30-32; 100-106) is placed side by side along the end wall (33,96). Each airtreatment module (30-32; 100-106) comprises a mixing unit (47,60) connected to an air intake chamber (46) for supplying outside air. A vertical air intake duct (45,62,68) is in fluid communication with the mixing unit (47,60) and extends from the mixing unit (47,60) into an upper part (50) ofthe airtreatment section (29,92) for recirculation ofair from the growing section. The mixing unit (47,60) is with its outlet connected to an air treatment unit (48,61) comprising a heat exchanger (80) and a blower (81). The modular airtreatment unit according to the invention allows easy construction, inspection and repair and provides for accurate and individualized climate control of rows of crop placed along an air tube connected to each airtreatment module.

Description

Air treatment system for a green house Field The invention relates to a greenhouse comprising walls and a roof structure defining an interior space having a growing section for growing crop and an air treatment section defined on one side by a wall of the greenhouse. The invention also relates to a method of constructing such a greenhouse and to an air treatment module for use in a greenhouse.

Background From EP1 464 219 a greenhouse is known in which in a growing section, a growth table extends in the length direction. On the growth table, the crop are placed in growing substrates. Below the growth table a perforated duct extends, into which air is blown by an air treatment unit. The air that is blown into the perforated duct exits from the duct in an upward direction and passes along the crop through openings in the growth tables. The air is evenly distributed along the length of the duct.

The air treatment unit is placed at the head of the growth table, at a distance from a side wall of the greenhouse and comprises a fan, a vertical air intake duct, a heat exchanger and an outside air intake duct extending through the side wall of the greenhouse for the intake of fresh ambient air. At the intersection of the vertical duct and the outside air intake duct, a valve is placed. The position of the valve controls the mixing of air that is recirculated from the growing section through the vertical duct with the controlled amount of outside air. The heat exchanger in the air treatment unit cools down the mixed air prior to it being blown into the perforated air duct, such that the air is dehumidified and can provide the desired amount of adiabatic cooling. Condensed water from the dehumidification step is collected in a tray below the perforated tube.

The known air treatment unit is of compact construction and is flexible so as to be easily adapted to provide a defined air flow with the required temperature for a large number of different crop, in particular for research into the growth conditions of different crop. it is an object of the present invention to provide a greenhouse and a method of construction comprising an air treatment section which provides controlled mixing of air that is recirculated from the growing section with outside air and which provides accurate temperature and humidity control of the air that is blown along the crop in the growing section.

It is another object of the invention to provide a greenhouse and method of construction, which allow efficient and reliable installation of large growing sections, containing a large number of crop. It is a further aim of the invention to provide a greenhouse in which the method of construction is flexible and allows easy access to the air treatment installation for maintenance and repair.

Summary of the invention Hereto a greenhouse according to the invention comprises in the air treatment section a number of air treatment modules placed side by side along at least half the length of the wall, preferably substantially along the length of the wall, each air treatment module comprising a mixing unit having a top surface with 40 an inlet in fluid communication with an air intake chamber that is adapted for supplying air from outside the greenhouse to the mixing unit, a vertical air intake duct that is in fluid communication with the inlet of the mixing module, the vertical duct extending from the top surface of the mixing module into an upper part of the air treatment section, the mixing unit having an air outlet situated in an air outlet plane at a distance from the side wall, the air outlet being in fluid communication with an air duct extending into the growing 45 section.

The modular construction of the air treatment assemblies according to the invention allow the construction of the outside walls and the roof structure of the greenhouse prior to placing of the air treatment modules. Varying greenhouse dimensions can be accommodated by using a suitable number of air treatment modules placed side by side along the side wall, at a close spacing or mutually adjacent. The air treatment modules can be placed along an end wall, extending in a transverse direction, with the air ducts extending in a length direction of the greenhouse.

It is also possible to place the air treatment modules along a side wall of the greenhouse extending in the length direction, while the air ducts extend in the transverse direction of the greenhouse. For certain crop, such as lettuce, this configuration has logistic and climatological advantages.

Each air treatment module can be designed to provide a specific heat exchange capacity and air transport capacity that is suitable for a specific row of crop along a predetermined air tube in the growing section. The mixing chambers of the air treatment modules may comprise internal deflection plates creating turbulence, for proper air mixing.

The mixing chambers may be provided with heat exchange members for heating or cooling the air passing through the mixing chamber. In an alternative embodiment, the outlet of the mixing units is connected to an air treatment unit comprising a heat exchanger and a blower, adapted for blowing air into the air ducts. The air treatment units may be connected to the mixing chamber, and can be easily demounted for servicing, repair or exchange.

The air treatment modules can be operated in a uniform manner across the length of the end wall, but can each be adjusted individually, or in groups, to vary the amounts outside air and recirculated air that are mixed, and to control temperature and humidity to be suited to local growing conditions of crop that is grown along an air tube inside the growing section. The size of the air treatment modules can be uniform but may vary across the width of the growing chamber. The mixing unit is preferably detachable from the air treatment module and from the vertical air intake duct.

The air treatment modules according to the invention can be easily accessed for inspection, maintenance or repair as they can be accessed from the side of the end wall. The air mixing units can be detached from their vertical duct and from their air treatment unit - that contains the fan and heat exchanger- , and all the units can be removed from the air treatment section of the greenhouse while leaving the growing section undisturbed.

The air intake chamber may comprise an opening in the end wall extending in the transverse direction 40 along a number of air treatment modules. The opening can be covered by an air permeable padding that acts as a filter and air humidifier for air being taking in from the ambient.

In an embodiment of a greenhouse according to the invention, the mixing unit has in its top surface a first inlet that is situated near the wall and a second inlet, the first and second inlets each comprising a valve 45 for closing of the inlets. By controlling each valve position, the mixing of the amounts of air in the mixing unit with the recirculated air can be accurately controlled for each air treatment module.

The valves in each mixing unit are of relatively small size and can be operated by means of small motor drive. The valves are creating relatively little turbulence and are subject to reduced vibration and wear of 50 the moving parts, such as the motors, bearings and connectors. The greenhouse according to the invention may comprise a controller that is adapted for controlling the position of the valves of each air treatment module, such that each module or group of modules provides air with a predetermined ratio of outside air and recirculated air and provides the air to the crop at a 55 predetermined air temperature and moisture content.

In an embodiment, the mixing units are of substantially parallelepiped shape with a top wall comprising the two valves, a rear part of the top wall comprising an outside air inlet valve and being situated in the bottom plane of the air take chamber, a front part of the top wall comprising a recirculated air inlet valve and being situated below the vertical air intake duct, a rear wall of the mixing unit being situated at or nearthe transverse wall.

In a further embodiment of a greenhouse according to the invention, the end wall and the mixing units are supported on respective elongate transverse support members that are spaced apart between 50 and 200 cm in the length direction of the greenhouse.

A method of constructing a greenhouse according to the invention comprises the steps of: constructing an enclosed growing section and an air treatment section defined by side walls, end walls and a roof structure, providing a number of air mixing units and placing the air mixing units in the air treatment section, side by side along a wall. The air treatment modules can be can be assembled at a construction site and then be transported to the greenhouse for installation. The construction of the modules can occur in parallel with the construction of the greenhouse, and the use of the modules according to the invention results in a shortened overall construction time. An air treatment module according to the invention comprises a mixing unit, an air treatment unit comprising a heat exchange element and a blower and a vertical duct adapted to be supported on a top surface of the mixing unit. Brief description of the drawings Some embodiments of a greenhouse according to the invention will by way of non-limiting example be described in detail with reference to the accompanying drawings. In the drawings: Fig. 1 shows a known greenhouse, Fig. 2 shows a perspective view of a greenhouse comprising a number of air treatment modules according to the invention, Figs. 3 and 4 each show a perspective view of the greenhouse of figure 2 from a different angle, Fig.5 shows a cross-sectional side view of an air treatment module according to the invention, Fig. 6 shows a schematic view of a controller connected to the air treatment modules according to the invention, and Fig. 7 shows another embodiment of the air treatment module of fig. 5. Detailed description of the invention 40 Figure 1 shows a known greenhouse 1 with a growing section 2 and an air treatment section 3. The growing section 2 comprises rows of crop 4 extending in the length direction L, wherein the length may range from 5 m to 100m or more. The crop are placed in beds 5 with a growing substrate that are situated over perforated air ducts, or tubes 6 that blow a uniformly distributed amount of warm or cold air upwards along the crop. From 5 to 50 or more assemblies of beds 5 and air ducts 6 may extend in the transverse 45 direction T of the greenhouse 1. The air treatment section 3 comprises an inner wall 7 that forms a separation from the growing section 2, with an air opening 8 at the top, that is closed off by a hinging cover 9. Air may be recirculated from the upper part of the growing section 2, as indicated by the arrow 11, into the air treatment section 3, and may be mixed with air 12 that is admitted from the ambient outside of the greenhouse 1 through a permeable pad wall 13. In the air treatment section 3, additional 50 heating and/or dehumidifying modules 15 may be placed for conditioning the air such as to have the desired temperature and humidity. The conditioned air is blown from the air treatment section 3 into the tubes 5 via fans 16. The end wall 18 of the greenhouse 1 at the top part carries the horizontal gutters 19 that support the glass roof panels 20, and may have a height of 4 m or more.

Figure 2 shows a perspective view of a greenhouse 25 according to the invention comprising a growing section 26 in which the air tubes 27, 28 extend in the length direction L.

In the air treatment section 29, a number of air treatment modules 30, 31, 32 are placed along the end wall 33 that extends in the transverse direction T.

The end wall 33 comprises a number of vertical columns 34, 35, 36 supported on a base structure 37. The vertical columns support horizontal beams 38, 39, 40 that form gutters for transport of rain water coming down from slanting roof structures 41, 42. Side walls 43 that extend from the base upwards to the horizontal beams 38-40 enclose the growing section 26. Each air treatment module comprises a vertical duct 45 with an air inlet 51, a mixing unit 47 of substantially parallelepiped shape, such as cubical, and an air treatment unit 48.The air treatment unit 48 comprises a heat exchanger and a blower that is connected to the air tubes 27, 28 for blowing air from the mixing unit 47 into the air tubes 27, 28. The end wall 29 is provided along its length with an opening, covered by padding material 44, for admitting ambient air into an air intake chamber 46. The mixing units 47 and air treatment units 48 are supported on the base structure 38 and on a support 49 that are spaced at a distance d of 40 cm or more, so that room is provided to accommodate electric leads for powering the fans and cooling medium ducts connected to the air treatment unit 48 and to heat exchangers that are accommodated in the air intake chamber 46. Air that is recirculated from an upper part 50 of the growing section 26, enters through the inlet 51 in the top part of the vertical ducts 45 of the air treatment modules 30-32 and enters in the mixing unit 47. Ambient air is drawn into the mixing units 47 via the padded opening 44 and the air intake chamber 46. The mixed air is blown into the air tubes 27, 28 via the air treatment units 48. From the air tubes 27, 28, the air is blown upwards along the crop that is supported on trays, gutters or tables 52, 53 that are situated over the tubes.

Figure 3 shows a perspective view of the air treatment modules with a mixing unit 60, vertical duct 62 and air treatment unit 61. The vertical duct connected to the mixing unit 60 has been omitted from the drawing.

In the rear part of the top wall 63 of the mixing unit 60, a valve 65 is placed for admitting air from the air take chamber 46. In the front part of the top wall 63, a valve 64 is placed for admitting air from the vertical duct into the mixing unit 60. The mixed air is blown into the tube 66 via the air treatment unit 61 along the crop placed on the tray 67. Figure 4 shows a perspective view of the air treatment modules with a vertical duct 68 placed on the front part of the mixing unit 60, over the valve 64. The mixing units that are shown in figures 2-4 are of uniform size, but it is also possible to use mixing units of varying width.

For instance, a large mixing unit may have a width of 2-5 of the units shown in figures 2-4, with a single heat exchange member and 2-5 blowers, one for each connected air tube.

Figure 5 shows a cross-sectional side view of the air treatment module 30 with the mixing unit 47 placed adjacent the end wall 33, directly below the bottom surface 69 of the air intake chamber 46. The rear aperture 70 in the top wall 71 of the mixing unit 47 is in fluid communication with the air intake chamber 46 and can be closed by a valve 74. A front aperture 72 in the top wall 71 is situated below the vertical duct 45, and can be closed off by a valve 73. The valves 73,74 can have a width of 35-50 cm and can pivot around an axis through their midline, so that they are balanced and can be operated by electric motors of 40 a relatively small size.

The amounts of outside air A1 and recirculated air R1 entering through the air inlet 51 of the duct 45, that are admitted into the mixing unit 47, are determined by the position of the valves 71,72. After cooling for dehumidification by the heat exchanger 80, a fan 81 blows the cool and dried air, or moisturized and heated air into the tube 27. The mixing unit 47 is placed below the air intake chamber 46 and is supported on the base structure 37 45 and on the support 49. The ducts 84 for the supply of heat exchange fluid and electrical leads 85 are accommodated in the space between the supports 37,49 and are easily accessible after removal of the mixing unit 47. The mixing unit 47 can be removed from the air treatment section 29 for access to the air treatment unit 48 for maintenance, repair or exchange via the end wall 33, without the need to pass through the growing section 26. A greenhouse according to the invention is constructed by first enclosing the growing section 26 and the air treatment section 29 by erecting the vertical columns 34-36, the horizontal beams 38-40 and the roof 5 structure 41,42. After placing of the end wall 33 and the side walls 43, the air treatment modules 30-32 are placed side by side against the end wall 33 and the air tubes are 27-28 are connected.

Figure 6 schematically shows a greenhouse 90 with longitudinal walls 93,94, end walls 95,96 and with a growing section 91, an air treatment section 92 and an air intake chamber 97 along the end wall 96. The air treatment modules 100-106 are connected to a controller 107 via control lines 108,109,110. The air treatment unit of each module 100-106 is connected to a respective air tube 111,112. The controller 107 regulates for each module the position of the valves of the mixing unit, the position of the valve of the vertical duct, the speed of the fan and the temperature of the heat exchanger.

The air treatment units 102- 104 are controlled as a group.

Figure 7 shows an embodiment of the air treatment module 30, in which the air mixing unit 47 comprises a single opening 72, the heat exchanger 80, and the fan 81 and is formed as an integral unit.

The valve 74 is placed in an opening in the side wall of air intake chamber 46. The vertical duct 45 is provided with an opening 76 through which air is admitted from the intake chamber 46. The opening 76 can be closed by the valve 74. The valve 73 is placed in the vertical duct 45, upstream of the opening 76. This allows for a pre-mixing step of controlled amounts of outside air and recirculated air in the lower part of the vertical duct 45, prior to the air entering into the combined mixing and air treatment unit 47. By hinging the valve 74 upwards, the airflow through the opening 76 into the vertical duct 45 can be controlled.

When the opening 76 is closed, no air flows from the intake chamber 46 into the mixing unit 47. In this case, the valve 73 is in the opened position so that only the recirculated air from the vertical duct 45 is admitted into the mixing chamber 47 through the opening 72.

Claims

Conclusions

Greenhouse (25,90) comprising walls (33,43,93,94,95,96) and a roof structure (41,42) defining an interior space with a growing section (26,91) for growing crops and a air treatment section (29,92), which is defined on one side by a wall (33,43,96) of the greenhouse, characterized in that the air treatment section (29,92) comprises a number of air treatment modules (30-32; 100-106 ) arranged side by side along at least half the length of the wall (33,43,93,94,95,96), preferably substantially along the length of the wall, each air handling module (30-32; 100-106) comprises: a mixing unit (47,60) comprising a top surface (71) having an inlet (70,72) in fluid communication with an air inlet chamber (46) adapted to supply air from outside the greenhouse to the mixing unit (47,60), a vertical air inlet duct (45,62,68) in fluid communication with the inlet (72) of the mixing unit (47,60), the vertical duct (45,62,68) extending extends from the top surface (71) of the mixing unit (47,60) into an upper portion (50) of the air handling section (29,92), the mixing unit (47,60) having an air outlet (75) located in an air outlet plane spaced from the end wall (33,96), the air outlet (75) being in fluid communication with an elongated air channel (27,28,111,112) extending longitudinally of the culturing section (26,91).

Greenhouse (25,90) according to claim 1, wherein the wall is formed by an end wall (33,96) extending in a transverse direction T, the air ducts (27,28,111,112) extending in a longitudinal direction L of the greenhouse .

Greenhouse (25,90) according to claim 1 or 2, wherein the outlet (75) of the mixing units (47,60) is connected to an air treatment unit (48,61) comprising a heat exchanger (80) and a fan (81) , which is adapted to blow air into the air ducts (27,28,11,112).

A greenhouse (25,90) according to claim 1, 2 or 3, wherein the air inlet chamber (46) comprises an opening in the wall (33,96) extending in the transverse direction along a number of air handling units.

Greenhouse (25,90) according to any one of claims 1 - 4, wherein the mixing unit (47,60) has a first inlet (70,72) in its top surface, which is located near the wall (33,96), and has a second inlet (72), the first and second inlets (70,72) of the air handling units each comprising a valve (64,65;73,74) for closing the inlets (70,72), the mixing unit (47, 60) can be removed from the vertical air inlet duct (45,62,68).

A greenhouse (25,90) according to claim 5, wherein a first valve (74) is spaced above the mixing unit (47), wherein the vertical channel (45) comprises an opening (76) which is in fluid communication with the air inlet chamber (46), the first valve (74) being adapted to control an airflow from the inlet chamber (48) into the vertical duct (45), through the opening (76).

Greenhouse (25,90) according to one of the preceding claims, comprising a control unit (107) adapted to control the position of the valves (64,65;73,74) of each air handling unit (30-32; 100-106), such that mixing units (47,60), or groups of mixing units, have different openings for providing a predetermined air temperature and a predetermined moisture content of the air exiting from each air handling unit (30-32; 100- 106) enters.

Greenhouse (25,90) according to one of the preceding claims, wherein the mixing units (47,60) have a substantially parallelepiped shape with a top wall (71) comprising the two valves (64,65;73,74), wherein a rear portion of the top wall (71) includes an outside air inlet valve (65,74), and is located in the bottom surface (69) of the air inlet chamber (46), a front portion of the top wall includes a recirculated air inlet valve (64,73) and is located below the vertical air inlet duct (45,62,68), and a rear wall located at or near the wall (33,96) of the greenhouse (25,90).

Greenhouse (25,90) according to one of the preceding claims, wherein the wall (33,96) and the mixing units (47,60) are supported on respective elongate transverse support elements (37,49) spaced between 50 and 200 mm. cm apart in the longitudinal direction of the greenhouse.

A method of constructing a greenhouse (25,90), comprising the steps of: constructing an enclosed growing section (26,91) and an air conditioning section (29,92) defined by side walls (43,93,94) ), end walls (33,95,96) and a roof structure (42), providing a plurality of air mixing units (47,60), and placing the air mixing units (47,60) in the air handling section (29,92), they on the side along a wall (33,43,93,94,95,96).

An air handling module (30-32; 100-106) comprising an air mixing unit (47,60) of generally parallelepiped shape, having an upper surface (71) with an inlet (70,72), a vertical air inlet duct (45,62 68) in fluid communication with the inlet (70,72) of the mixing unit (47,60), the vertical channel (45,62,68) extending from the top surface (71) of the mixing unit (47,60) ), wherein the mixing unit (47,60) has an air outlet (75) located in an air outlet plane located in a side wall of the mixing unit (47,60) below the valve.

The air handling module (30-32; 100-106) of claim 11, wherein the top surface 40 (71) has a first inlet (70) and a second inlet (72), each inlet (70, 72) having a valve.

(64,65;73,74) for closing the inlets (70,72), the vertical air inlet duct (45,62,68) being in fluid communication with the second inlet (72).

13. Air treatment module according to claim 11 or 12, wherein the mixing unit comprises a heat exchange element.

An air handling module according to claim 11, 12 or 13, wherein the mixing unit comprises internal air deflection elements.

An air handling module according to any one of claims 11 to 14, comprising an air handling unit (48,61) connected to the air outlet (75), comprising a heat exchange element (80) and a fan (81).