Dehumidifier for an enclosed grow shelter, installation comprising an enclosed grow shelter and a process for dehumidifying air in an enclosed grow shelter

Abstract

TITLE OF THE INVENTION: DEHUMIDIFIER FOR AN ENCLOSED GROWING SHELTER, INSTALLATION COMPRISING AN ENCLOSED GROWING SHELTER AND METHOD FOR DEHUMIDIFYING AIR IN AN ENCLOSED GROWING SHELTER. The dehumidifier for an enclosed growing shelter comprises: - a first circuit (515) for transporting a first airflow in a predetermined direction, - a second circuit (530) for transporting a second airflow, - a cyclically regenerating desiccant device (510) of which a portion to be regenerated (511) is positioned in the first circuit to be traversed by the first airflow and a desiccant portion (512) for capturing water in the second airflow is positioned in the second circuit to be traversed by the second airflow, - a refrigeration unit comprising a condenser (517) for heating the first airflow and an evaporator (518) of Cooling of the first airflow, such as,In the first circuit: - the condenser is connected upstream of the portion to be regenerated, and - the evaporator is connected downstream of the portion to be regenerated. (Figure for the abbreviation: figure 5).

Description

Title of the invention: DEHUMIDIFIER FOR ENCLOSED GROWING SHELTER, INSTALLATION COMPRISING AN ENCLOSED GROWING SHELTER AND METHOD FOR AIR DEHUMIDIFICATION IN AN ENCLOSED GROWING SHELTER Technical field of the invention

[0001] The invention relates to the field of dehumidification of enclosed growing shelters such as greenhouses. More specifically, it relates to a dehumidifier for an enclosed growing shelter, an installation comprising an enclosed growing shelter, and a method for dehumidifying the air inside an enclosed growing shelter.

[0002] An example of an enclosed growing shelter as used here is a greenhouse. As used here, the expression "enclosed growing shelter" also covers rooms with artificial lighting where indoor cultivation, often called "indoor cultivation," is practiced. State of the art

[0003] In greenhouses, and particularly in agricultural greenhouses, excessive humidity is common. This leads to condensation forming on the crops, degrading their quality. Furthermore, the development of diseases, fungi, mold, and / or pests is encouraged when the greenhouse is too humid. In addition, excessively humid air in the greenhouse slows the growth of cultivated plants.

[0004] To combat the effects of excessive humidity on greenhouse crops, farmers and market gardeners use costly and polluting plant protection treatments. To dehumidify, producers heat the greenhouse and then ventilate it, for example by opening the top, which results in energy consumption that can represent 20% to 50% of the total annual energy consumption for a greenhouse.

[0005] In addition, products rendered unsaleable in crops by excess moisture must be removed, resulting in a loss of income and time wasted on sorting.

[0006] Dehumidification devices for an enclosed culture shelter are known.

[0007] Represented in [Fig. 1], a known dehumidification device 100 for an enclosed growing shelter such as a greenhouse 101 uses a dehumidification method generally called thermodynamic dehumidification. This dehumidification device 100 comprises a refrigeration unit of which only the evaporator 102 and the condenser 103 are shown in [Fig. 1] for clarity. The airflow extracted from the greenhouse and drawn through the dehumidifier 100 by a fan 104 is symbolized by the straight arrows in [Fig. 1]. In the dehumidifier 100, the air first passes through the evaporator 102 where water present in the air condenses and forms condensate, i.e., liquid water 105, which is drained away. After losing water through cooling in the evaporator 102, the air is reheated through the condenser 103 and then returned to the greenhouse 101.

[0008] The dehumidification device 100 is effective in dehumidifying the air in the greenhouse 101 when the air in the greenhouse 101 has a temperature of around 15 °C to 25 °C.

[0009] Unfortunately, the dehumidification device 100 is not very effective or not effective at dehumidifying the air in the greenhouse 101 when the air in the greenhouse 101 has a temperature of around 0 °C to 10 °C.

[0010] A first reason for the ineffectiveness of dehumidification by the dehumidification device 100 at temperatures in the greenhouse 101 of approximately 0 °C to 10 °C is explained below. When the temperature in the greenhouse 101 is between 0 °C and 10 °C, the refrigerant evaporates in the evaporator 102 between -10 °C and 0 °C, causing the evaporator 102 to frost over; that is, the water vapor in the air freezes upon contact with the evaporator 102 and forms ice. To remove the frost and recover the water from this frost, defrosting cycles are necessary. Defrosting is energy-intensive if it is carried out by electric heating elements or by reversing the cycle. If it is done with hot gases, it only consumes the power of the refrigeration unit's compressor, but the cycle is long and sometimes insufficient.Finally, for temperatures in the greenhouse above 5°C, defrosting with air drawn from greenhouse 101 works, but the cycle is very long. During defrosting, the dehumidifier 100 no longer dehumidifies the air in greenhouse 101. If defrosting is triggered too late, the evaporator 102 becomes encased in ice, causing a malfunction. If defrosting is triggered too early, energy and operating time are wasted.

[0011] A second reason for the lack of effectiveness of dehumidification by the dehumidification device 100 at temperatures in the greenhouse 101 of the order of 0 °C to 10 °C is explained below. Cold air contains little moisture in the form of vapor. For a given evaporator 102 power that lowers the temperature of the air passing through this evaporator 102 by 10 °C, the amount of water extracted from the air by the dehumidification device 100 is 4 g of water per kilogram of air for a greenhouse 101 containing air at 20 °C and 80% humidity, 3 g of water per kilogram of air for a greenhouse 101 containing air at 10 °C and 80% humidity, and 2 g of water per kilogram of air for a greenhouse 101 containing air at 0 °C. and 80% humidity. We can see that the dehumidification capacity of the dehumidification device 100 decreases with the decrease in the temperature of the treated air.

[0012] A third reason for the ineffectiveness of dehumidification by the dehumidifier 100 at temperatures in the greenhouse 101 of approximately 0 °C to 10 °C is explained below. The colder the air in the greenhouse 101, the lower the required evaporation temperature to condense the water in the humid air. For example, consider that the evaporation temperature of the refrigerant in the evaporator 102 is +5 °C. Furthermore, consider that the compressor in the refrigeration unit has a rated cooling capacity of 20 kW. The cooling power of this compressor decreases with the temperature of the air in the greenhouse: it is 18.3 kW for a temperature Tserre of 20 °C of the air in greenhouse 101, 14.3 kW for a temperature Tserre of 10 °C of the air in greenhouse 101, and 10.3 kW for a temperature Tserre of 0 °C of the air in greenhouse 101.The compressor of the refrigeration unit loses 25 to 50% of its capacity to produce usable cooling power to dehumidify the air in greenhouse 101.

[0013] The aforementioned disadvantages of the dehumidification device 100 also apply in the case of an enclosed growing shelter other than a greenhouse. For example, they also apply when the dehumidification device 100 dehumidifies the air contained in an indoor growing room with artificial lighting.

[0014] Represented in [Fig. 2], a known dehumidification device 200 for a greenhouse 201 uses a dehumidification method generally called adsorption dehumidification. This dehumidification device 200 comprises a desiccant wheel 206, a portion of which is to be regenerated through which an airflow 208 passes, preferably extracted from the greenhouse 201. A desiccant portion of the desiccant wheel 206 is traversed by an airflow 209 extracted from the greenhouse 201 and returned to the greenhouse 201 after being dried by the desiccant portion. The air from the airflow 208 passes through a heating device 207 where it is heated before passing through the portion of the desiccant wheel 206 to be regenerated. In the heating device 207, the air from the airflow 208 is heated to increase its capacity to extract water from the desiccant wheel 206. Summary of the invention

[0015] The invention has at least the aim of improving the efficiency of air dehumidification in a closed culture shelter when the air in the closed culture shelter is cold.

[0016] According to the invention, this goal is achieved by means of a dehumidifier for a closed growing shelter, which comprises: - a first transport circuit for a first airflow in a predetermined direction, - a second transport circuit for a second airflow, - a cyclically regenerating desiccant device, a portion to be regenerated being positioned in the first circuit to be traversed by the first airflow, and a desiccant portion to capture water in the second airflow being positioned in the second circuit to be traversed by the second airflow; - a refrigeration unit comprising a condenser for heating the first airflow and an evaporator for cooling the first airflow, which are such that: * The condenser is connected in the first circuit, upstream of the portion of the desiccant device to be regenerated, and * The evaporator is connected in the first circuit, downstream of the portion to be regenerated of the desiccant device.

[0017] As used in this description and in the attached claims, the term "refrigeration unit" covers all devices for producing cold, regardless of the technology used, and, in particular, heat pumps and adsorption refrigerators.

[0018] The invention has several advantages, the first of which is that the dehumidifier for closed growing shelters according to the invention has high energy efficiency and consumes little energy, making it compatible with closed growing shelters that can be connected to low power electricity sources.

[0019] The dehumidifier for closed growing shelters according to the invention has a second advantage: it can operate using electricity as its sole energy source. By comparison, the known dehumidification device 200 has high energy consumption. For this reason, it is most often used in conjunction with a hot water network or a fossil fuel source such as natural gas or diesel fuel, even though the heating device 207 can also be heated by means of electric resistances. When a hot water network is used to operate the dehumidification device 200, the hot water from this network is used to heat the heating device 207.In the case of using a fossil fuel for the operation of the dehumidification device 200, the heat from the combustion of this fossil fuel is used to heat the heating device 207 by means of a heat transfer fluid such as water.

[0020] The dehumidifier for closed growing shelters according to the invention has a third advantage: it is simple to install. In particular, the dehumidifier for closed growing shelters according to the invention is connected to a closed growing shelter in such a way that the air from the first airflow and the air from the second airflow originate from and return to the closed growing shelter. Therefore, the dehumidifier for closed growing shelters according to the invention can be installed inside a greenhouse without using an air duct for air supply between the two. The dehumidifier is located outside the greenhouse without requiring a hole for the air duct to pass through a wall of the greenhouse. By comparison, in the known dehumidification device 200, the air that has undergone regeneration by the desiccant wheel 206 must be discharged outside the greenhouse. It is noteworthy that the dehumidifier for a closed growing shelter according to the invention can be placed virtually anywhere inside the closed growing shelter. In particular, the dehumidifier for a closed growing shelter according to the invention can be placed in a central area of ​​the closed growing shelter or in another area where good dehumidification of the entire closed growing shelter can be achieved using the dehumidifier.

[0021] The dehumidifier for closed growing shelter defined above may incorporate one or more other advantageous features, alone or in combination, in particular among those defined below.

[0022] According to an advantageous possibility, the dehumidifier for closed growing shelter includes a heat exchanger connected in the first circuit to establish a heat exchange relationship between the first airflow in a first section of the first circuit and this first airflow in a second section of the first circuit, the first section of the first circuit being located between the portion to be regenerated of the desiccant device and the evaporator, the second section of the first circuit being located downstream of the evaporator.

[0023] Thus, the first airflow exiting the evaporator can cool this same first airflow before it enters the evaporator. When the first airflow enters the evaporator after being cooled in the heat exchanger, its relative humidity has increased due to the cooling in the heat exchanger, so that the condensation of the water present in the first airflow occurs more efficiently in the evaporator.

[0024] According to an advantageous embodiment, the dehumidifier for a closed growing shelter includes a bypass branch which passes away from the desiccant device and connects in the first circuit, between the desiccant device and the evaporator, the condenser being a first condenser, the dehumidifier for a closed growing shelter including a second condenser, the dehumidifier being switchable between a first state, in which the first and second circuits are operational and in which the bypass branch is closed, and a second state, in which the second condenser is connected in the first circuit, downstream of the evaporator, and in which the bypass branch is open and substituted in the first circuit for a switchable section including the desiccant device.

[0025] Thus, the dehumidifier for closed growing shelters is able to effectively dehumidify the air in the greenhouse even when the air in the greenhouse is cold, by For example, it is more effective at temperatures ranging from 0°C to 10°C than when the air inside the greenhouse is warm, for example, from 10°C to 25°C and above. In its first configuration, the dehumidifier for closed greenhouses effectively dehumidifies the air extracted from the greenhouse when the air inside is cold (for example, between 0°C and 10°C). In its second configuration, the dehumidifier for closed greenhouses effectively dehumidifies the air extracted from the greenhouse when the air inside is warm (for example, between 10°C and 30°C). Therefore, the dehumidifier for closed greenhouses is versatile.

[0026] According to an advantageous possibility, the dehumidifier for a closed growing shelter is such that, in the first state, the first condenser is operational within the cooling unit by being connected in a closed circuit including the evaporator, and such that, in the second state, the second condenser is operational within the cooling unit by being substituted for the first condenser in the closed circuit.

[0027] Thus, several components, including the evaporator, are used in both the first and second states and are therefore not duplicated. This results in simplification and cost savings when the dehumidifier for a closed growing shelter is multi-purpose.

[0028] According to an advantageous possibility, the dehumidifier for closed growing shelter includes a control and command device configured to measure the ambient temperature and to switch the dehumidifier from the second state to the first state when the ambient temperature falls below a first predetermined threshold.

[0029] Thus, the switching between the second and first states can be automated so as to be a function of changes in the air temperature in the greenhouse. Once the dehumidifier is connected to a greenhouse, the ambient temperature can, in particular, be the ambient temperature in the greenhouse, that is to say, the air temperature inside the greenhouse.

[0030] According to an advantageous possibility, the first predetermined threshold is chosen in a range from about 8 °C to about 12 °C.

[0031] According to an advantageous possibility, the control and command device is configured to switch the dehumidifier from the first state to the second state when the ambient temperature rises above a second predetermined threshold.

[0032] According to an advantageous possibility, the second predetermined threshold is chosen in a range from about 8 °C to about 12 °C.

[0033] According to an advantageous possibility, the dehumidifier for closed growing shelter includes drive means capable of setting in motion the air of the first and second air streams.

[0034] The invention also relates to an installation which includes a closed growing shelter having an interior volume filled with air, which includes a dehumidifier for a closed growing shelter as defined above, and in which an inlet of the first circuit, an inlet of the second circuit, an outlet of the first circuit and an outlet of the second circuit are in fluidic communication with the interior volume of the greenhouse.

[0035] According to an advantageous possibility, the first circuit passes away from the drying portion of the desiccant device.

[0036] Thus, all or virtually all of the drying portion can be devoted to treating the second air stream. The efficiency of this drying portion, in terms of the amount of water captured in the second air stream, is high.

[0037] The invention further relates to a method for dehumidifying air present inside a greenhouse, which includes regeneration and treatment, wherein the regeneration comprises steps in which: a) A first stream of air from an internal volume of the greenhouse is heated through a condenser of a refrigeration unit, b) using the first airflow heated in step a), a portion to be regenerated of a cyclically regenerating desiccant device is at least partially regenerated by passing the first airflow through this portion to be regenerated; c) after step b), the first airflow is cooled through an evaporator of the refrigeration unit so that water present in the first airflow condenses in the evaporator to be discharged in liquid form. d) the first airflow from the portion of the desiccant device to be regenerated is directed to the internal volume of the greenhouse, in which the treatment includes steps in which: e) Water is extracted from a second airflow originating from the interior volume of the greenhouse, by passing this second airflow through a desiccant portion of the desiccant device, f) the second airflow from the drying portion of the desiccant device is directed to the internal volume of the greenhouse.

[0038] In this process, regeneration and treatment are preferably simultaneous. However, this can not be the case. For example, regeneration and treatment can alternate, even occurring simultaneously during overlapping periods. Furthermore, regeneration can be temporarily interrupted while treatment continues continuously. Similarly, treatment can be temporarily interrupted while generation continues continuously. The choice among these different operating modes can be made to optimize parameters such as the energy efficiency of the dehumidification process, according to the invention. Furthermore, at least two of these different modes of operation can be combined. Brief description of the figures

[0039] Other advantages and features will become clearer from the following description of several particular embodiments of the invention, given by way of non-limiting example and shown in the accompanying drawings, among which:

[0040] [Fig. 1] is a schematic view of a greenhouse connected to a dehumidifier according to a prior art,

[0041] [Fig.2] is a schematic view of a greenhouse connected to a dehumidifier according to a second prior art,

[0042] [Fig.3] is a schematic view of an installation in which a greenhouse is connected to a dehumidifier for a closed growing shelter according to a first embodiment of the invention,

[0043] [Fig.4] is a schematic view of a sub-assembly of a dehumidifier for a closed growing shelter according to a second embodiment of the invention,

[0044] [Fig.5] is a schematic view of an installation in which the dehumidifier for a closed growing shelter according to the second embodiment of the invention is connected to a greenhouse and is in a first state and in a first operating mode associated with this first state,

[0045] [Fig.6] is a schematic view which represents the same installation as [Fig.5] and in which the dehumidifier for a closed growing shelter according to the second embodiment is in a second state and in a second operating mode associated with this second state, and

[0046] [Fig.7] represents, in the form of a flowchart, the steps of the greenhouse dehumidification process which is the subject of the invention. Description of the implementation methods

[0047] In [Fig.3], a dehumidifier 300 is a dehumidifier for a closed growing shelter according to a first embodiment of the invention.

[0048] The dehumidifier 300 includes a cyclically regenerating desiccant device, which comprises a desiccant wheel 310 in the example shown. The desiccant wheel 310 is known per se and is surrounded by a casing, which is not shown for clarity. This casing and the desiccant wheel 310 together delimit several zones, including a regeneration zone located above the dashed line L in [Fig. 3] and a desiccation zone located below the dashed line L in [Fig. 3].

[0049] A portion to be regenerated 311 of the desiccant wheel 310 is located in the regeneration zone. A desiccant portion 312 of the desiccant wheel 310 is located in the drying zone. The desiccant wheel 310 can be rotated on its axis, for example by being driven by a motor. By rotating the desiccant wheel 310, a portion of the desiccant wheel 310 is moved from the regeneration zone to the drying zone, while at the same time a portion of the desiccant wheel 310 is moved from the drying zone to the regeneration zone.

[0050] The desiccant wheel is traversed from end to end by channels which are parallel to each other and arranged relative to each other in a honeycomb structure. The walls of these channels are coated with an adsorbent material capable of alternately adsorbing and desorbing water.

[0051] The dehumidifier 300 includes a first circuit 315 for transporting a first airflow in a predetermined direction, which is symbolized by the direction of the arrows representing this first circuit 315 on the [Fig.3].

[0052] The first circuit 315 includes an inlet 316 which is connected to the interior volume of an enclosed growing shelter, which is a greenhouse 301 in the example shown. A condenser 317 for heating the first airflow is connected in the first circuit 315, downstream of the inlet 316.

[0053] The portion to be regenerated 311 of the desiccant wheel 310 is positioned in the first circuit 315, downstream of the condenser 317, to be traversed by the first airflow.

[0054] The condenser 317 is part of a refrigeration unit which also includes a first airflow cooling evaporator 318. In a manner known per se, this refrigeration unit may also include a compressor (not shown) and an expansion valve (not shown), which connecting lines (not shown) link to the condenser 317 and the evaporator 318 in a closed circuit containing a refrigerant.

[0055] In the first embodiment described above, the cooling unit is a compression-type heat pump. The cooling unit can also be of the adsorption type, in which case it does not include an expansion valve or a compressor.

[0056] The evaporator 318 is connected in the first circuit 315, downstream of the portion to be regenerated 311 of the desiccant wheel 310.

[0057] A heat exchanger 320 is connected in the first circuit 315 at two points so as to establish a heat exchange relationship between the first airflow and itself. More specifically, the first airflow circulating from the portion to be regenerated 311 to the evaporator 318 exchanges heat, in the heat exchanger 320, with the first airflow exiting the evaporator 318 and heading towards the outlet 322 of the first circuit 315. This outlet 322 is connected to the interior volume of the greenhouse 301.

[0058] The dehumidifier 300 includes a second circuit 330 for transporting a second airflow. The direction of circulation of the second airflow in the second circuit 330 is symbolized by the direction of the arrows representing this second circuit 330 on [Fig.3].

[0059] The second circuit 330 includes an inlet 331 which is connected to the internal volume of the greenhouse 301. The desiccant portion 312 of the desiccant wheel 310 is positioned in the second circuit 330, between the inlet 331 and an outlet 332 of the second circuit 330.

[0060] In the example shown, outlet 332 is a connection of the second circuit 330 to the first circuit 315. It follows that the second airflow is mixed with the first airflow before being discharged into the interior volume of the greenhouse 301. In variants (not shown), the outlet of the first circuit and the outlet of the second circuit are separate and configured to be connected independently of each other to the interior volume of the greenhouse 1. In this case, the second airflow circulates in the second circuit in the same direction as that shown in [Fig.3] or in the opposite direction.

[0061] Still in the example shown, the inlet 316 of the first circuit 315 and the inlet 331 of the second circuit 330 are separate from each other. In variants (not shown), the first and second circuits have a common inlet to be connected to the internal volume of the greenhouse 301.

[0062] The dehumidifier 300 includes drive means (not shown) for moving the air in the first and second airflows. These drive means may include a fan common to the first circuit 315 and the second circuit 330. In the case of such a common fan, one or more valves may be configured to regulate the flow rates of the first and / or second airflows. The drive means may also include several fans, one of which is configured in the first circuit 315 to move the air in the first airflow, and another of which is configured in the second circuit 330 to move the air in the second airflow.

[0063] When the dehumidifier is operating, it undergoes treatment and regeneration, which can be simultaneous as is the case in the example described below.

[0064] The treatment is a second airflow treatment. In this treatment, humid air is drawn from inside the greenhouse 301 and drawn into the second circuit 330 to form the second airflow. The drying portion 312 captures water from the second airflow as it passes through the second circuit 330.

[0065] Regeneration takes place at the level of the first circuit 315.

[0066] Air is drawn from inside the greenhouse 301 and drawn into the first circuit 315 to form the second airflow. As it passes through the condenser 317, the air in the first airflow is heated, which lowers its relative humidity and increases its capacity to take on water and therefore to regenerate the portion to be regenerated 311 in the desiccant wheel 310.

[0067] The air from the first airflow passes through the part to be regenerated 311 after passing through the condenser 317. When it passes through the part to be regenerated 311, the air from the first airflow extracts water from this part to be regenerated, which it thus regenerates.

[0068] Between the regenerated portion 311 of the desiccant wheel 310 and the evaporator 318, the air from the first airflow passes through the heat exchanger 320 for the first time, during which it is cooled. The relative humidity of the first airflow increases as it cools through the heat exchanger 320.

[0069] The air from the first airflow passes through the evaporator 318 after passing only once through the heat exchanger 320. As it passes through the evaporator 318, the air from the first airflow is cooled. Water present in the first airflow then condenses in the evaporator 318 and flows out as condensate 340, which is discharged. The amount of water condensing in the evaporator 318 from the first airflow is greater the more this first airflow has been previously cooled in the heat exchanger 320.

[0070] The first airflow is less loaded with water and colder after the evaporator 318 than before the evaporator 318.

[0071] After passing through the evaporator 318, the air from the first airflow passes a second time through the heat exchanger 320. The air that passes through the heat exchanger 320 the second time is heated by the air that passed through this heat exchanger 320 the first time. By passing through the heat exchanger 320 the second time, the air from the first airflow becomes warmer and its relative humidity decreases.

[0072] After passing through the heat exchanger 320 a second time, the air from the first airflow is sent to the interior volume of the greenhouse 301.

[0073] During regeneration, the portion to be regenerated 311 in the desiccant wheel 310 releases water and is regenerated. During the treatment of the second air stream, the drying portion 312 in the desiccant wheel 310 becomes saturated with water. At certain times, the desiccant wheel 310 is rotated by a certain angle. For example, the desiccant wheel 310 is rotated by half a turn at certain times, so that the portion to be regenerated 311 and the drying portion 312 are no longer the same portions of the desiccant wheel 310. In alternative configurations, the desiccant wheel 310 is rotated continuously.

[0074] The heat exchanger 320 can be removed. A dehumidifier according to an embodiment of the invention is the dehumidifier 300 without the heat exchanger 320.

[0075] Figure 4 schematically represents a subassembly 400 forming part of a dehumidifier 500 according to a second embodiment of the invention. Visible In figures 5 and 6, the 500 dehumidifier is a dehumidifier for closed growing shelters.

[0076] Like the dehumidifier 300, the dehumidifier 500 includes air drive means. The drive means of the dehumidifier 500 may be identical to those of the dehumidifier 300. In the example shown, they include a fan 545 and a fan 546 visible in [Fig. 5].

[0077] As illustrated in [Fig.4], the subassembly 400 comprises a refrigeration unit which includes a condenser 517, an evaporator 518, a compressor 550 and an expansion valve 551. The compressor 550, the condenser 517, the expansion valve 551 and the evaporator 518 are connected together in a closed circuit 552, which contains a refrigerant in a manner known per se.

[0078] In what follows, only those features of the dehumidifier 500 that distinguish it from the dehumidifier 300 are described. Furthermore, when a referenced part of the dehumidifier 500 is identical or equivalent to a referenced part of the dehumidifier 300, its reference is constructed by adding 200 to the reference designating that referenced part on the dehumidifier 300. In this way, the references of the condenser 517 and the evaporator 518 are constructed, in particular.

[0079] Condenser 517 is a first condenser. Subassembly 400 includes a second condenser, which is the condenser referenced 555 in Figures 4 to 6.

[0080] As illustrated in [Fig.4], the second condenser 555 is connected in parallel with the first condenser 517. A valve 556 is connected in one of the two parallel branches, each of which includes one of the condensers 517 and 555. A valve 557 is connected in the other branch of these two parallel branches.

[0081] In a first state, the valve 556 is open, while the valve 557 is closed so that the second condenser 555 is not connected in the closed circuit 552. On [Fig.4], the subassembly 400 is in the first state, in which the refrigerant circulates in the closed circuit 552 in the direction indicated by arrowheads added to the lines symbolizing the connections.

[0082] Valves 556 and 557 allow the subassembly 400 to be switched between the first state and a second state in which the second condenser 555 replaces the first condenser 517 in the closed circuit. In this second state, valve 557 is open, while valve 556 is closed. Valves 556 and 557 may, in particular, be solenoid valves controlled by a control and command device 570, the connections of which to the various elements of the dehumidifier 500 are not shown for the sake of clarity.

[0083] The dehumidifier 500 is configured to dehumidify the air present in the interior volume of an enclosed growing shelter, which is the greenhouse 501 visible in Figures 5 and 6 in the example shown.

[0084] The condenser 555 is connected in the first circuit 515, downstream of the evaporator 518.

[0085] As illustrated in [Fig.6], the dehumidifier 500 includes a bypass branch 560 which passes away from the desiccant wheel 510 and connects to the first circuit 515, between the portion to be regenerated 511 of this desiccant wheel 510 and the evaporator 518.

[0086] The dehumidifier 500 may or may not include the heat exchanger 320. In the example shown, the dehumidifier 500 does not include the heat exchanger 320.

[0087] A register 561 connected in the bypass branch 560 forms part of a switching means, which includes valves 556 and 557, as well as other components known per se but not shown for clarity. By means of these switching means, the dehumidifier 500 is switchable between the first and second states.

[0088] In [Fig. 5], the dehumidifier 500 is in its first state. When the dehumidifier 500 is in the first state, the condenser 555 is inactive and the damper 561 is closed.

[0089] When in the first state, the dehumidifier 500 has the same operation as the dehumidifier 300 except with regard to the heat exchanger 320. When in the first state, the dehumidifier 500 has exactly the same operation as the dehumidifier 300 in the case where it includes the heat exchanger 320 like the dehumidifier 300.

[0090] The operation of the dehumidifier 500 in the first state is a first mode of operation among the first and second modes of operation of the dehumidifier 500.

[0091] In its first mode of operation, the 500 dehumidifier is very effective at dehumidifying air with a temperature between approximately 0 °C and approximately 10 °C.

[0092] In the first operating mode of the dehumidifier 500, the fan 545 is running and draws air from the first airflow into the first circuit 515. In the first operating mode of the dehumidifier 500, the fan 546 is running and draws air from the second airflow into the second circuit 530.

[0093] In [Fig.6], the dehumidifier 500 is in its second state.

[0094] When the dehumidifier 500 is in the second state, there is no airflow in the second circuit 530 and the desiccant wheel 510 is inactive.

[0095] When the dehumidifier 500 is in the second state, the register 561 is open and the bypass branch 560 is substituted, in the first circuit 515, for a deactivatable section comprising the portion to be regenerated 511 of the desiccant wheel 510 and the condenser 517.

[0096] Even when the dehumidifier 500 is in the second state, the condenser 517 is inactive, while the condenser 555 is active.

[0097] When in the second state, the 500 dehumidifier can operate according to its second operating mode.

[0098] In the second operating mode of the dehumidifier 500, the fan 545 is running and draws air into the first circuit 515.

[0099] In the second operating mode of the dehumidifier 500, the fan 546 may be off, as shown in [Fig. 6]. In the second operating mode of the dehumidifier 500, the fan 546 may also be on in order to increase the air circulation rate inside the greenhouse 501.

[0100] In the second operating mode of the dehumidifier 500, humid air is taken from the greenhouse 501 and enters the dehumidifier 500 through the open register 561 and the bypass branch 560. This air is drawn in as a single airflow and passes through the evaporator 518 and then the condenser 555.

[0101] When it passes through the evaporator 518, the air in the single airflow is cooled and reaches its dew point. Water present in the single airflow condenses in the evaporator 518 and then flows out as condensate 540, which is discharged.

[0102] When it passes through the condenser 555, the air of the single airflow is heated. After being heated through the condenser 555, the air of the single airflow is discharged into the interior volume of the greenhouse 501.

[0103] In the second operating mode, the 500 dehumidifier is very effective at dehumidifying air with a temperature between approximately 10 °C and approximately 25 °C.

[0104] The 500 dehumidifier is versatile in that it can operate in the first operating mode to dehumidify air at a temperature between approximately 0 °C and approximately 10 °C, and in the second operating mode to dehumidify air at a temperature between approximately 10 °C and approximately 25 °C.

[0105] The control and command device 570 is configured to measure the ambient temperature and to switch the dehumidifier 500 from the second state to the first state when this ambient temperature falls below a first predetermined threshold, which may be, for example, on the order of 10 °C. For example, the ambient temperature may be the ambient temperature in the interior volume of the greenhouse 501, that is, the air temperature in the interior volume of the greenhouse 501.

[0106] The control and command device 570 is configured to switch the dehumidifier 500 from the first state to the second state when the ambient temperature rises above a second predetermined threshold, preferably different from the first predetermined threshold. The second predetermined threshold may be, for example, around 12 °C.

[0107] In the example shown, the condenser 555 is connected in the first circuit 515 in the second state of the dehumidifier 500, in addition to being connected in the first state of the dehumidifier 500. In the second operating mode of the dehumidifier 500, the condenser 555 is traversed by the first airflow even though it is inactive. In variants (not shown), the condenser 555 is connected in the first circuit 515 only when the dehumidifier 500 is in the second state.

[0108] We observe, in [Fig.7], a particular embodiment of the process 700 for dehumidifying air present inside a greenhouse, which is the subject of the invention.

[0109] This process 700 includes a regeneration 705 and a treatment 710.

[0110] Regeneration 705 comprises the following steps: a) a step 715, during which a first airflow from an internal volume of the greenhouse 301, 501 is heated through a condenser 317, 517 of a refrigeration unit, b) a step 720, during which a portion to be regenerated 311, 511 of a cyclically regenerating desiccant device 310, 510 is at least partially regenerated by passing the first airflow through this portion to be regenerated 311, 511 using the first airflow heated in step a), (c) after step 720, a step 725, in which the first air stream is cooled through an evaporator 318, 518 of the refrigeration unit so that water present in the first air stream condenses in the evaporator 318, 518 to be discharged in liquid form, and d) a step 730, during which the first airflow from the portion to be regenerated (311, 511) of the desiccant device 310, 510 is directed to the internal volume of the greenhouse 301,501.

[0111] Process 710 comprises the following steps: (e) a step 735, in which water is extracted from a second airflow originating from the internal volume of the greenhouse 301, 501, by passing this second airflow through a desiccating portion 312, 512 of the desiccant device 310, 510, and f) a step 740, during which the second airflow from the drying portion 312, 512 of the desiccant device 310, 510 is directed to the internal volume of the greenhouse 301, 501.

[0112] Example 1:

[0113] A first example is given. This is an example of operation with the dehumidifier 300. In this first example, air at 10 °C and 75% humidity is taken from the interior volume of the greenhouse 301, by the first circuit 315 and by the second circuit 330.

[0114] At the outlet of the desiccant portion 312 of the desiccant wheel 310 in the second circuit 330, the air of the second airflow is at 16 °C and 40% humidity.

[0115] At the outlet of the condenser 317 and at the inlet of the part to be regenerated 311 of the desiccant wheel 310 in the first circuit 315, the air of the first airflow is at 39 °C and 15% humidity.

[0116] At the outlet of the part to be regenerated 311 of the desiccant wheel 310 and at the inlet of the heat exchanger 320 (before the first passage through it), the air of the first airflow is at 21 °C and 70% humidity.

[0117] At the outlet of the heat exchanger 320 (after the first passage through it) and at the inlet of the evaporator 318, the air of the first airflow is at 12 °C and 100% humidity.

[0118] At the outlet of the evaporator 318 and at the inlet of the heat exchanger 320 (before the second passage through it), the air of the first airflow is at 2 °C and 100% humidity.

[0119] At the outlet of the heat exchanger 320 (after the second passage through it) and before reaching the outlet 332 of the second circuit 330, the air of the first airflow is at 25 °C and 20% humidity.

[0120] The air resulting from the mixing of the first airflow and the second airflow downstream of outlet 332 of the second circuit 330 is at 23 °C and 20% humidity. It is discharged into the interior volume of the greenhouse 301.

[0121] Example 2:

[0122] A second example is given. This is an example of operation with the dehumidifier 500 in the first state, that is to say an example of the first mode of operation of the dehumidifier 500. In this second example, air at 5 °C and 75% humidity is taken from the interior volume of the greenhouse 501, by the first circuit 515 and by the second circuit 530.

[0123] At the outlet of the desiccant portion 512 of the desiccant wheel 510 in the second circuit 530, the air of the second airflow is at 10 °C and 35% humidity.

[0124] At the outlet of the condenser 517 and at the inlet of the part to be regenerated 511 of the desiccant wheel 510 in the first circuit 515, the air of the first airflow is at 40 °C and 10% humidity.

[0125] At the outlet of the part to be regenerated 511 of the desiccant wheel 510 and at the inlet of the evaporator 518, the air of the first airflow is at 17 °C and 70% humidity.

[0126] At the outlet of the evaporator 518 and before reaching the outlet 532 of the second circuit 530, the air of the first airflow is at 3 °C and 100% humidity.

[0127] The air resulting from the mixing of the first airflow and the second airflow downstream of outlet 532 of the second circuit 530 is at 9 °C and 50% humidity. It is discharged into the interior volume of the greenhouse 501.

[0128] Example 3:

[0129] A third example is given. This is an example of operation with the dehumidifier 500 in the second state, that is to say an example of the second operating mode of the dehumidifier 500. In this third example, air at 20 °C and 75% humidity is taken from the interior volume of the greenhouse 501, through the open register 561.

[0130] At the outlet of the evaporator 518 and at the inlet of the condenser 555, the air of the single airflow is at 11 °C and 100% humidity.

[0131] At the outlet of the condenser 555, the air from the single airflow is at 30 °C and 30% humidity. This air is discharged into the interior volume of the greenhouse 501.

[0132] The invention is not limited to the embodiments described above. In particular, either of the greenhouses 301 and 501 can be replaced by an indoor growing room with artificial lighting without departing from the scope of the invention.

Claims

Demands

1. A dehumidifier (300, 500) for a closed growing shelter (301, 501), characterized in that it comprises: - a first circuit (315, 515) for transporting a first airflow in a predetermined direction, - a second circuit (330, 530) for transporting a second airflow, - a cyclically regenerating desiccant device (310, 510) of which a portion to be regenerated (311, 511) is positioned in the first circuit (315, 515) to be traversed by the first airflow and a desiccant portion (312, 512) for capturing water in the second airflow is positioned in the second circuit (330, 530) to be traversed by the second airflow, - a refrigeration unit comprising a condenser (317, 517) of heating of the first airflow and an evaporator (318, 518) configured to cool and dehumidify the first airflow, by condensation of water present in the first airflow, which are such that: * the condenser (317,517) is connected in the first circuit (315, 515), upstream of the portion to be regenerated (311, 511) of the desiccant device (310, 510), and * the evaporator (318, 518) is connected in the first circuit (315, 515), downstream of the portion to be regenerated (311, 511) of the desiccant device (310, 510).

2. Dehumidifier (300, 500) according to claim 1, which includes a heat exchanger (320) connected in the first circuit (315, 515) to establish a heat exchange relationship between the first airflow in a first section of the first circuit (315, 515) and the first airflow in a second section of the first circuit (315, 515), the first section of the first circuit (315, 515) being located between the portion to be regenerated (311, 511) of the desiccant device (310, 510) and the evaporator (318, 518), the second section of the first circuit (315, 515) being located downstream of the evaporator (318, 518).

3. Dehumidifier (500) according to claim 1 or 2, - comprising a bypass branch (560) which draws air from the closed culture shelter, passes away from the desiccant device (310, 510) and connects in the first circuit (315, 515), between the desiccant device (310, 510) and the evaporator (318, 518), and - wherein the condenser (317, 517) is a first condenser, the dehumidifier comprising a second condenser (555), the dehumidifier being switchable between a first state, in which the first and second circuits (330, 530) are operational and in which the bypass branch (560) is closed, and a second state, in which the second condenser (555) is connected in the first circuit (315, 515), downstream of the evaporator (318, 518), and in which the bypass branch (560) is open and substituted in the first circuit (315, 515) for a switchable section comprising the desiccant device (310, 510).

4. Dehumidifier according to claim 3, wherein, in the first state, the first condenser (317, 517) is operational within the cooling unit by being connected in a closed circuit (552) comprising the evaporator (318, 518), and wherein, in the second state, the second condenser (555) is operational within the cooling unit by being substituted for the first condenser (317, 517) in the closed circuit (552).

5. Dehumidifier according to any one of claims 3 or 4, which includes a control and command device (570) configured to measure the ambient temperature and to switch the dehumidifier from the second state to the first state when the ambient temperature falls below a first predetermined threshold.

6. Dehumidifier according to claim 5, wherein the first predetermined threshold is chosen from a range of about 8 °C to about 12 °C.

7. Dehumidifier according to any one of claims 5 or 6, wherein the control and command device (570) is configured to switch the dehumidifier from the first state to the second state when the ambient temperature rises above a second predetermined threshold.

8. Dehumidifier according to claim 7, wherein the second predetermined threshold is chosen from a range of about 8 °C to about 12 °C.

9. Dehumidifier according to any one of claims 1 to 8, which includes drive means (545, 546) capable of setting in motion the air of the first and second air streams.

10. Installation comprising an enclosed growing shelter (301, 501) having an internal volume filled with air, characterized in that it comprises a dehumidifier according to any one of claims 1 to 9, and in that an inlet (316) of the first circuit (315, 515), an inlet (331) of the second circuit (330, 530), an outlet (322) of the first circuit (315, 515) and an outlet (332, 532) of the second circuit (330, 530) are in fluidic communication with the internal volume of the enclosed growing shelter (301, 501).

11. Installation according to claim 10, wherein the first circuit (315, 515) passes away from the drying portion of the desiccant device (310, 510).

12. A method (700) for dehumidifying air inside a closed growing shelter (301, 501), characterized in that it comprises a regeneration (705) and a treatment (710), wherein the regeneration (705) comprises steps in which: a) a first airflow from an internal volume of the closed growing shelter (301, 501) is heated (715) through a condenser (317, 517) of a refrigeration unit; b) using the first airflow heated in step a), a portion to be regenerated (311, 511) of a cyclically regenerating desiccant device (310, 510) is at least partially regenerated (720) by passing the first airflow through this portion to be regenerated (311, 511); c) after In step b), the first air stream (725) is cooled and dehumidified through an evaporator (318, 518) of the refrigeration unit so that water present in the first air stream condenses in the evaporator (318,518) to be discharged in liquid form, d) the first airflow (730) from the portion to be regenerated (311, 511) of the desiccant device (310, 510) is conducted to the interior volume of the closed culture shelter (301, 501), in which the treatment (710) includes steps in which: e) water (735) is extracted from a second airflow originating from the interior volume of the closed culture shelter (301, 501), by, pass this second airflow through a desiccating portion (312, 512) of the desiccant device (310, 510), f) the second airflow (740) from the desiccating portion (312, 512) of the desiccating device (310, 510) is conducted to the internal volume of the closed culture shelter (301, 501).

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