FR2618048A1 - Air conditioned greenhouse with distillation - Google Patents

Abstract

The greenhouse according to the invention comprises a roof 2, side walls 3, 4 and an intermediate wall 5. The intermediate wall 5 is sealed and delimits an upper compartment 7 for the distillation of brackish water, and a lower growing compartment 6. The brackish water pumped from an external tank 8 flows over the intermediate wall 5 formed by a succession of trays and is gathered in a collector 13 then returned to the external tank 8. Part of it evaporates and is condensed under the roof 2, under which it flows and is gathered in collectors which return it to a fresh water tank 17. The fresh water is used for growing the plants on the internal ground 1.

Description

DISTILLATION AIR CONDITIONED GREENHOUSE
The present invention relates to greenhouses for intensive cultivation of plants, and more particularly greenhouses in which the fresh water used for cultivation is obtained by distillation of brackish water in the greenhouse itself.

 Patent DE-A-1 632 943 describes a method for operating a greenhouse from brackish water the greenhouse comprises a glass interior surface on which, by an appropriate distribution, salt water flows in a thin layer; a gutter catches up with this water and brings it back into a tank of water to be distilled, from which it is again extracted to be brought to the glazed interior surface; part of the water evaporates and condenses on the underside of a glass roof; the water condensed on the roof is collected and stored in a fresh water tank. However, this document does not give details on the actual structure of the greenhouse.

 The same process was repeated in patent EP-B-5 103, in which the greenhouse is provided with an intermediate wall formed by a plurality of inclined and orientable panels, not joined, on which the brackish water flows. from the center to the cities.

 We also know, in particular in patent FR-A1 168 575, greenhouses in which raised tanks are arranged between the roof and the floor of the greenhouse, the tanks containing brackish water which, after evaporation, comes to condense under the roof of the greenhouse and drains into recovery tanks. Brackish water tanks occupy only part of the surface of the greenhouse.

 In these known methods and devices, the greenhouse is actually formed of a single compartment with, inside, elements for evaporating brackish water and elements for condensing and collecting distilled water. As a result, it is very difficult to control the humidity of the atmosphere in which the plants develop, and it is very difficult to obtain both a good distillation yield for the production of fresh water. and a good plant development yield in the same greenhouse. In certain conditions of sunshine, it even turns out to be almost impossible to reconcile the distillation and the development of plants, and the greenhouse cannot function.

 Furthermore, in particular in the devices described above, the greenhouse structures are not suitable for installation and operation in underdeveloped countries: they are made up of heavy and bulky parts, which require special handling means. for their mounting; and their maintenance is difficult, in particular as regards the intermediate surface, on which flows brackish strip.

 The object of the present invention is in particular to avoid the drawbacks of known methods and devices, by proposing a new greenhouse structure making it possible to control the hygrometry of the atmosphere surrounding the cultures independently of the operation of the brackish water distillation means. . This makes it possible to increase both the yield of the distillation and the yield of the crops, and such a greenhouse can be used whatever the climatic conditions.

 According to another object, the present invention makes it possible to design a greenhouse formed by assembling elements which are all manipulable by a single man. In particular, the structure of the intermediate surface is such that it is obtained by assembling plates of transparent material simply placed on support frames, with interposition of seals, the plates thus being easy to install, easy to change.

 According to another object, the intermediate surface is easy to clean without dismantling and without handling, so that maintenance can be ensured by unskilled labor.

 Thus, the greenhouse according to the invention makes it possible to use, for irrigation, water which is not potable or unfit for cultivation and to transform it into potable water which can be used for cultivation.

 The water distillation means simultaneously provide air conditioning of the greenhouse, thanks to the structure of the intermediate surface which ensures the maintenance of a certain quantity of water in suspension in tanks.

 The greenhouse according to the invention is also provided with reflective outer films, which can be unwound when the solar radiation becomes too strong.

 Thanks to the particular structure of the greenhouse according to the invention, it is possible to eliminate the use of air extractors or carbon dioxide injectors, which are necessary in a conventional greenhouse, thanks to a system of lateral openings. closable.

 To achieve these and other objects, the greenhouse according to the present invention comprises - an internal soil partially or totally covered with a medium suitable for cultivation, - an intermediate surface intended to support a flow of water to be distilled, the intermediate surface being formed of a material allowing the solar rays to filter, - side walls surrounding the interior floor, - a roof comprising walls transparent to solar radiation and having the desired inclination so that the evaporated strip of the intermediate surface can condense and flow under the transparent roof walls, - first pipes to bring water to be distilled from a water tank to be distilled to the intermediate surface, - second pipes to bring undistilled water from the wall intermediate to the water tank to be distilled, - third pipes to collect the condensed water and bring it to a fresh water tank, - fourth pipes to bring fresh water from the fresh water tank to the internal soil.

 According to a preferred embodiment, the intermediate wall is substantially horizontal and the roof defines, with said intermediate wall, an upper compartment whose height is sufficient in the central part for the passage of a user carrying out maintenance. The upper compartment is therefore accessible for the installation and maintenance of the transparent plates forming the intermediate wall.

We also note, with this structure, that we limit the height to which we must raise the brackish water to ensure its flow on the intermediate wall.

 According to one embodiment of the invention, the intermediate wall is formed of transverse beams, attached to the roof and to the side walls of the greenhouse, and supporting beams in inverted T, the whole defining a grid supporting plates of material transparent laid on the horizontal edges of the side members and beams with the interposition of a layer of elastomer and sealing with a silicone seal. It is then possible to use plates of material which are particularly inexpensive, easy to install and to change, easy to clean.

 Preferably, screw jacks allow the height adjustment of the side members relative to the transverse beams, making it possible to define a transverse slope between the successive trays, and making it possible to adjust and cancel the longitudinal slope. of each bin.

 Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in conjunction with the attached figures, among which - FIG. 1 is a schematic overview in cross section of a tunnel greenhouse according to the present invention - Figure 2 is a schematic perspective view of a chapel greenhouse according to the present invention - Figure 3 is a schematic cross-sectional view of the supporting structure of the greenhouse according to the invention; - Figure 4 is a cross section of the profile forming the waxing - Figures 5 and 6 respectively represent an end view and a top view of the brackish water collector according to an embodiment of the invention - Figure 7 shows a side view of the side frame assembly part - Figure 8 schematically shows an intermediate frame assembly part for a chapel greenhouse - Figure 9 is a detail of the assembly between the roof and the intermediate wall - FIGS. 10 and 11 respectively represent an end view and a top view of an intermediate spar of an intermediate wall - FIGS. 12 and 13 respectively represent an end view and a top view of a distilled water collector; and - Figures 14 and 15 show respectively, in cross section and in top view, the assembly of the side members, transverse beams and transparent plates forming the intermediate wall.

 As shown schematically in Figure 1, the greenhouse according to the invention comprises an internal soil 1, partially or completely covered with a medium suitable for cultivation, a roof 2 having walls transparent to solar radiation, side walls 3 and 4 surrounding the ground 1 and also made of a material transparent to solar radiation, and an intermediate wall 5.

 The intermediate wall 5 sealingly separates a lower compartment 6 intended for cultivation and an upper compartment 7 intended for the distillation of water and for air conditioning.

 Water to be distilled is contained in a tank of distilled water 8. It can be brackish water, water unsuitable for cultivation. The greenhouse also works with fresh water. The water contained in the distilled water tank 8 is pumped by a pump 9, for example a solar energy pump, to be raised by first pipes 10 to the level of the intermediate wall 5, on the edges of which it is injected by longitudinal distributors 11 and 12. The water to be distilled flows on the intermediate wall 5. Part of the water, under the action of solar radiation passing through the roof 2, evaporates and comes condensing on the underside of the roof 2. The excess water to be distilled is collected in a brackish water collector 13, and is returned to the tank 8 by second pipes 14.

 The roof 2 has a sufficient inclination, greater than 304, so that the water which condenses under its underside can flow and be collected in lateral fresh water collectors 15 and 16, the fresh water then being brought to a fresh water tank 17 through third pipes 18. The fresh water tank 17 is slightly below the level of the intermediate wall 5, so that the fresh water flows naturally to the tank 17. A tank fertilizer 19 is disposed at an intermediate level between the fresh water tank 17 and the soil 1. A pipe 20 allows fresh water to be brought into the fertilization tank 19 from the fresh water tank 17, and a pipe 21 makes it possible to bring the fertilized water from the tank 19 to the ground 1.

 Gutters 22 and 23 laterally line the base of the roof 2, and collect rainwater. The rainwater can then be sent to the fresh water tank 17.

 The side walls 3 and 4 comprise a reflective film such as the film 24, tisposed outside the wall, and removable.

According to one embodiment, the film can be wound around a longitudinal tube to be completely retracted, or unroll to cover all of the walls 3 and 4.

 FIG. 1 represents a greenhouse of the tunnel type, comprising a single vault.

 FIG. 2 schematically represents a greenhouse of the chapel type, obtained by juxtaposition of two arches 25 and 26 joined sideways. The parts 25 and 26 have upper compartments 27 and 28 separated from each other, the lower compartments 29 and 30 being able to communicate with each other.

 The supporting structure of the greenhouse according to the invention is obtained.

from profiles whose cross-section is chosen for very easy assembly. The position of the different mattress parts is shown diagrammatically in FIG. 3. The ridge piece A, shown in end view in FIG. 4, is a profile having lateral lips for the embedding of the transparent plates and of the beams forming the roof.

 The brackish water collector 13, shown in FIGS. 5 and 6, has a U-shaped section with two horizontal lateral flanges.

 On the sides of the greenhouse, the junction between the roof beams 31 and the uprights 32 of side walls is provided by a connecting piece B shown in FIG. 7. According to one embodiment, the uprights 32 are produced by the assembly of two inverted U-shaped profiles forming an H, the central part 33 of the part B being inserted between the two U at the upper end of the upright. The outer leg 34 of the part B carries the rainwater collecting gutters such as the gutters 22 or 23. The upper part 35 of the part B is secured to the corresponding beam 31 of the roof.

The assembly is carried out for example by bolting in holes as shown in FIG. 7. the upper part 35 of the part B further comprises means for assembling the transverse beams forming the intermediate wall 5.

 At the intersection of two beams 36 and 37 and an upright 38 of a chapel greenhouse, as shown in Figure 3, the joining of the beams and the uprights is ensured by a double connecting piece E as shown schematically in FIG. 8, shaped similarly to part B in FIG. 7.

 FIG. 9 shows the assembly of the main parts constituting the intermediate wall 5 with the assembly part B and the roof 2. The intermediate wall 5 for this comprises transverse beams 37, formed of symmetrical half-beams such as the half-beam 37A and the half-beam 37B, separated by the central zone of the greenhouse. your half-beam 37A has a first end 38 connected to the part 36 of the part B by bolting, and a second end 39 suspended by a tie rod 40 connecting it to a beam of the roof 2. The half-beam 37A is substantially horizontal , its orientation being adjusted by the tie rod 40. The second end 39 of the half-beam 37A supports one of the sides of the manifold 13. Your half-beam 37A has an inverted T-section, with two lateral lower flanges forming a support for receiving and supporting the ends of side members such as the side member 41 and transparent plates forming the 'intermediate wall 5.

 The parts B are shaped to support, in their central zone, a fresh water collector 42, shown in detail in FIGS. 12 and 13. The collector 42 is connected by a bracket 43 to the base plane formed by the edges of the beam 37A. The longitudinal members 41 are shown in more detail in FIGS. 10 and 11, and have an inverted T-shaped section, the lateral wings of which form a support for receiving the transparent plates forming the intermediate wall 5.

 Figures 14 and 15 show the assembly of beams such as the beam 41 and beams such as the beam 37A, forming a grid for supporting plates of transparent material such as the plate 43. The plate 43, of rectangular shape, rests by its four edges on the wings of the side members and beams, with the interposition of a layer of elastomer 44. The seal is ensured by a silicone seal 45, for example a silicone paste deposited during the assembly of the wall. torsion of the wall assembly, the orientation of the side members 41 is adjusted by operating yis jacks arranged at their ends relative to the corresponding beams 37A. Preferably, the side members are horizontal, and a succession can be defined of plates = lles that the plate 43 forming a succession of stepped trays gradually descending from the first end 38 of the transverse beam to the second end 39. It is however possible to provide trays arranged in the same horizontal plane. A series of tanks is thus produced, in which the brackish water flows successively from the sides until it is collected in the central collector 13. The top 410 of the side members 41 protrudes by a height h above the defined level by the upper surfaces of the plates 43. Preferably the height h is approximately 7 millimeters.

 The roof 2 of the greenhouse must form, with respect to the horizontal, an angle of at least 30. This angle conditions the good flow of the condensed water under the wall. In some cases, it can be fitted with manual or automatic lifting shading. Preferably, the roof has a dimension such that, in its middle part, it has a height of about 3 meters relative to the intermediate wall 5. In this way, the collector 13 can also serve as a gateway for a user ensuring the maintenance and cleaning of the intermediate wall 5.

 The intermediate wall 5 can advantageously be placed at a height of about 3 meters above the ground.

 The upper compartment 7 is closed at its two ends by two gables, at least one of which has a door which gives access to the gangway formed by the manifold 13. This door is also used as a safety valve in the event of vacuum or overpressure in the upper compartment 7, and for this includes a ratchet opening in both directions in the event of pressure.

 The intermediate wall sealingly separates the upper compartment 7 and the lower compartment 6, to facilitate distillation in the upper compartment 7 and to avoid the problems that too high relative humidity could cause the cultures in the lower compartment 6.

 According to another embodiment, the intermediate wall may have a slightly different structure, with an elevated central walkway, and two halves of intermediate wall 5 inclined laterally outwards, two brackish water collectors being arranged in the vicinity of the side walls. of the greenhouse. The supply of the intermediate wall 5 with brackish water is done by a distributor near the center, and the water flows outwards.

 The lower compartment 6 is equipped, over the entire length and on each side, with a manual or automatic opening system, starting from the ground level up to the height of the intermediate wall 5.

This compartment can also be fitted with a removable reflective film. The lower compartment is closed at each of its ends by a pinion made of plastic film or polycarbonate- or glass.

Doors are provided for the lower parts, allowing access to agricultural machinery. The foundations are made of resin or steel or concrete bases.

 The reflective film provided in the lower part of the side walls allows, when lowered and placed outside the greenhouse, to reduce the temperature inside the greenhouse when the solar radiation is very important.

 It also makes it possible, at night, when it is deployed inside the greenhouse, to reflect the radiation emitted by the soil and thus to raise the interior temperature of the greenhouse during the night. This application can be useful in cold temperate zones.

 The mass of water suspended in the tanks of the intermediate wall 5 is not negligible. It allows, according to the principle of the storage of calories in hot hours and their return in cold hours, uniform and stable air conditioning of the greenhouse. The air conditioning is improved by the addition of the external tank 8, dug on the ground, outside the greenhouse.

The volume of the reservoir 8 is chosen according to the size of the greenhouse and the local climatic conditions.

 In addition to tank 8, the addition of a pumping of a cold water source, such as a well or the sea, is envisaged in countries where the minimum temperatures are too high and could not lower the temperature enough inside the greenhouse without harming crops. In this case, during the hottest hours, the greenhouse would operate without the use of tank 8.

 For cold or cold temperate countries, in the first case, a low voltage resistor can be installed in the tank 8 to raise the strip temperature. In the second case, it is possible to heat only the water which will be brought to the feet of the plants.

 To operate, the greenhouse requires only a low-flow pump to raise the brackish water from ground level to its intermediate wall 5: approximately 3 meters. A solar pump coupled to accumulators or a pump with a generator allows complete autonomy of the greenhouse energy. All lifting or opening systems can be manual or automatic.

 The non-potable water is mounted on the intermediate wall, by the distributors 11 and 12, where it overflows from tank to tank before flowing into the central collector 13 which returns the water outside the greenhouse in the tank 8. The flow rate of pump 9 can be adjusted according to the flow requirements.

 The water condensed under the underside of the roof 2 flows on each side and is collected in the fresh water collectors 15 and 16. It is then directed by gravity into the fresh water tank 17. From this fresh water tank 17, it is drawn into the fertilization tank 19. In the fertilization tank are added the trace elements necessary for cultivation. The water leaves the fertilization tank by gravity and is led to the feet of the cultivated plants, by capillaries. The plants are for example in rock wool, or peat, in tubs filled with pebbles or sand, the length of the greenhouse, which end in containers allowing to recover the fertilized water not used by the plant.

This water is returned to the fertilization tank.

 In a more elaborate embodiment, the greenhouse according to the present invention further comprises - a greenhouse management system: opening of the greenhouse as a function of the interior and exterior temperatures of the greenhouse, and of wind speed; - a lifting of the shading system also a function of the interior and exterior temperatures of the greenhouse, but also of the water temperature on the collectors and of the sunshine, - a system for regulating the hydraulic circuit.

 The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below.

Claims (9)

 1 - Air-conditioned greenhouse, comprising - an internal soil (1) partially or totally covered with a medium suitable for cultivation, - an intermediate surface (5) intended to support a flow of water to be distilled, the intermediate surface being formed by '' a material allowing the sun's rays to filter, - side walls (3, 4) surrounding the interior floor (1), - a roof (2) comprising walls transparent to solar radiation and having the desired inclination so that the water evaporated from the intermediate surface can condense and flow under the transparent roof walls, - first pipes (10) to bring water to be distilled from a distilled water tank (8) to the intermediate surface ( 5), - second pipes (14) for bringing undistilled water from the intermediate wall (5) to the water tank to be distilled (8), - third pipes (18) for collecting condensed water and bring it to a fresh water tank (17), - fourth pipes (20, 21) for bringing fresh water from the fresh water tank to the internal soil (-1), characterized in that the intermediate surface (5) is an intermediate wall separating from sealingly a cc- = lower srtiment (6) intended for cultivation and an upper compartment (7) intended for the distillation of water and air conditioning, and in that said intermediate wall (5) is formed by the juxtaposition of several pools.  2 - Air-conditioned greenhouse according to claim 1, characterized in that the intermediate wall (5) is substantially horizontal and the roof defines, with the intermediate wall, an upper compartment (7) whose height is sufficient in the central part for the passage of '' a user performing maintenance.  3 - Greenhouse according to one of claims 1 or 2, characterized in that the side walls (3, 4) of the lower compartment include a reflective film (24) removable that can be deployed at 1 t outside.  4 - Greenhouse according to any one of claims 1 to 3, characterized in that the side walls (3, 4) of the lower compartment include closable openings.  5 - Greenhouse according to any one of claims 1 to 4, characterized in that the intermediate wall (5) is formed of transverse beams (37), attached to the roof and to the side walls of the greenhouse, and supporting beams ( 41) in inverted T, the transverse beams having lateral edges on which the longitudinal members rest, the assembly defining a grid supporting plates (43) of transparent material placed on the horizontal edges of the longitudinal members and beams with the interposition of a layer elastomer (44), the assembly being sealed by a silicone seal (45).  6 - Greenhouse according to claim 5, characterized in that it comprises cylinders for adjusting the height of the side members relative to the transverse beams.  7 - Greenhouse according to claim 6, characterized in that the transverse beams are each formed by two half-beams (37A, 37B) separated by the central area of the greenhouse, a first end (38) of the half-beam being fixed to the corresponding wall of the greenhouse, the second end being supported by a tie rod (40) fixed to the roof.  8 - Greenhouse according to any one of claims 1 to 7, characterized in that it comprises a median longitudinal collector (13), simultaneously forming means for collecting undistilled water and maintenance or laying bridge.  9 - Greenhouse according to any one of claims 1 to 8, characterized in that it comprises a fresh water tank (17) disposed slightly below the level of its intermediate wall (5), and a fertilization tank (19), arranged at an intermediate level between the fresh water tank (17) and the interior floor (1).