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 CLOSED GROWING SHELTER, INSTALLATION COMPRISING A CLOSED GROWING SHELTER AND METHOD FOR DEHUMIDIFYING AIR IN A CLOSED GROWING SHELTER Technical field of the invention

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

[0002] An example of a closed growing shelter as used herein is a greenhouse. As used herein, the term "closed growing shelter" also covers rooms with artificial lighting where indoor growing, often referred to as "indoor growing," is practiced. State of the art

[0003] In greenhouses, particularly agricultural greenhouses, excess humidity is common. This leads to water condensation being deposited on the crops and degrading their quality. In addition, 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 down the growth of cultivated plants.

[0004] To combat the consequences of excess humidity on greenhouse crops, farmers and market gardeners use phytosanitary treatments that are expensive and polluting. To dehumidify, producers proceed by heating the greenhouse and then ventilating it by opening it, for example, from above, which results in energy consumption that can represent 20% to 50% of the total annual energy consumption for a greenhouse.

[0005] In addition, produce made unsaleable in the harvest due to excess moisture must be removed, resulting in lost revenue and time wasted sorting.

[0006] Devices for dehumidifying a closed growing shelter are known.

[0007] Shown in [Fig.l], a known device 100 for dehumidifying a closed growing shelter such as a greenhouse 101 uses dehumidification 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.l] for the sake of clarity. The flow of air extracted from the greenhouse and driven through the dehumidification device 100 by a fan 104 is symbolized by the straight arrows in [Fig.l]. In the dehumidification device 100, the air first passes through the evaporator 102 where water present in the air condenses and forms condensates, i.e. liquid water 105 which is discharged. After losing water by 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 for dehumidifying the air in the greenhouse 101 when the air in the greenhouse 101 has a temperature of about 15°C to 25°C.

[0009] Unfortunately, the dehumidification device 100 is of little or no effect in dehumidifying the air in the greenhouse 101 when the air in the greenhouse 101 has a temperature of the order of 0°C to 10°C.

[0010] A first reason for the lack of efficiency of dehumidification by the dehumidification device 100 for temperatures in the greenhouse 101 of the order of 0°C to 10°C is explained in the following. When the temperature in the greenhouse 101 is of the order of 0°C to 10°C, the evaporation of the refrigerant in the evaporator 102 takes place between -10 and 0°C, which causes the evaporator 102 to frost, that is to say the water contained in the air freezes on 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 done by electrical resistors or by cycle inversion. If it is done by hot gases, it only consumes the power of the compressor of the refrigeration unit, but the cycle is long and sometimes insufficient.Finally, for temperatures in the greenhouse above 5°C, defrosting with air taken from the greenhouse 101 works, but the cycle is very long. During defrosting, the dehumidification device 100 no longer dehumidifies the air in the greenhouse 101. If defrosting is triggered too late, the evaporator 102 is caught in an envelope of ice, which generates a breakdown. If defrosting is triggered too early, energy and operating time are wasted unnecessarily.

[0011] A second reason for the lack of efficiency of dehumidification by the dehumidification device 100 for temperatures in the greenhouse 101 of the order of 0°C to 10°C is explained in the following. Cold air contains little moisture in the form of vapor. For a given power of the evaporator 102 allowing the temperature of the air passing through this evaporator 102 to be lowered by 10°C, the quantity 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. It can be seen 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 lack of efficiency of dehumidification by the dehumidification device 100 for temperatures in the greenhouse 101 of the order of 0°C to 10°C is explained in the following. The colder the air in the greenhouse 101, the lower the evaporation temperature is required to condense the water in the humid air. Consider, for example, that the evaporation temperature of the refrigerant in the evaporator 102 is +5°C. Consider further that the compressor in the refrigeration unit has a nominal refrigeration power of 20 kW. The cooling power of this compressor decreases with the air temperature in the greenhouse: it is 18.3 kW for an air temperature Tserre of 20 °C in greenhouse 101, 14.3 kW for an air temperature Tserre of 10 °C in greenhouse 101, and 10.3 kW for an air temperature Tserre of 0 °C in greenhouse 101.The compressor of the refrigeration unit loses 25 to 50% of its capacity to produce usable refrigeration power to dehumidify the air in the greenhouse 101. .

[0013] The above-mentioned disadvantages of the dehumidification device 100 also apply in the case of a closed 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] Shown in [Fig. 2], a known device 200 for dehumidifying a greenhouse 201 uses dehumidification generally called adsorption dehumidification. This dehumidification device 200 comprises a desiccant wheel 206, a portion of which to be regenerated is crossed by an air flow 208 preferably extracted from the greenhouse 201. A drying portion of the desiccant wheel 206 is crossed by an air flow 209 extracted from the greenhouse 201 and returned to this greenhouse 201 after having been dried by the drying portion. The air of the air stream 208 passes through a heater 207 where it is heated before passing through the portion of the desiccant wheel 206 to be regenerated. In the heater 207, the air of the air stream 208 is heated so that its ability to extract water from the desiccant wheel 206 is increased. Summary of the Invention

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

[0016] According to the invention, this aim is achieved by means of a dehumidifier for a closed growing shelter, which comprises: - a first circuit for transporting a first air flow in a predetermined direction, - a second circuit for transporting a second air flow, - a cyclic regeneration desiccant device, a portion of which to be regenerated is positioned in the first circuit to be crossed by the first air flow and of which a desiccation portion for capturing water in the second air flow is positioned in the second circuit to be crossed by the second air flow, - a refrigeration unit comprising a condenser for heating the first air flow and an evaporator for cooling the first air flow, 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 the present description and in the appended claims, the expression "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 a closed growing shelter according to the invention has a high energy efficiency and consumes little energy, which makes it compatible with closed growing shelters connectable to low-power electricity sources.

[0019] The dehumidifier for a closed growing shelter according to the invention has the second advantage of being able to operate with electricity as the sole energy source. In comparison, the known dehumidification device 200 has a high energy consumption. For this reason, it is most often used in association with a hot water network or a fossil fuel source such as natural gas or diesel, even if the heating device 207 can also be heated by means of electrical resistors. In the case of using a hot water network for the operation of the dehumidification device 200, the hot water from this network is used for heating the heating device 207.In the case of the use of a fossil fuel for the operation of the dehumidification device 200, the heat resulting from the combustion of this fossil fuel is used for heating the heating device 207 by means of a heat transfer liquid such as water.

[0020] The dehumidifier for a closed growing shelter according to the invention has the third advantage of being simple to install. In particular, the dehumidifier for a closed growing shelter according to the invention is to be connected to a closed growing shelter in such a way that the air of the first air flow and the air of the second air flow come from the closed growing shelter and return to this closed growing shelter. The dehumidifier for a closed growing shelter according to the invention can therefore be installed inside a greenhouse without using an air duct for conveying air between the dehumidifier and the outside of the greenhouse and without a hole for the passage of this air duct having to be made in a wall of the greenhouse. By comparison, in the dehumidification device dification 200 known, the air having carried out a regeneration of the desiccant wheel 206 must be discharged outside the greenhouse. It is noteworthy that the dehumidifier for closed growing shelter according to the invention can be placed practically anywhere inside the closed growing shelter. In particular, the dehumidifier for 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 for closed growing shelter.

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

[0022] According to an advantageous possibility, the dehumidifier for a closed growing shelter comprises a heat exchanger connected in the first circuit to put the first air flow in a first section of the first circuit into heat exchange relation with this first air flow 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 air flow leaving the evaporator can cool this same first air flow before it enters the evaporator. When the first air flow enters the evaporator after having been cooled in the heat exchanger, its relative humidity has increased by the cooling in the heat exchanger so that the condensation of the water present in the first air flow takes place more efficiently in the evaporator.

[0024] According to an advantageous possibility, the dehumidifier for a closed growing shelter comprises 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 comprising 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 deactivatable section comprising the desiccant device.

[0025] Thus, the dehumidifier for a closed growing shelter is able to effectively dehumidify the air in the greenhouse both when the air in the greenhouse is cold, for example at a temperature of the order of 0°C to 10°C, and when the air in the greenhouse is hot, for example at a temperature of the order of 10°C to 25°C and above. The The first state of a closed grow room dehumidifier effectively dehumidifies the greenhouse exhaust air when the air in the greenhouse is cold (e.g., between 0°C and 10°C). The second state of a closed grow room dehumidifier effectively dehumidifies the greenhouse exhaust air when the air in the greenhouse is warm (e.g., between 10°C and 30°C). This makes the closed grow room dehumidifier 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 comprising 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 the first state as in the second state and are therefore not duplicated. Simplification and savings are thus obtained in the case where the dehumidifier for closed growing shelter is versatile.

[0028] According to an advantageous possibility, the dehumidifier for a closed growing shelter comprises 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 the first state can be automated so as to be a function of the changes in 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 temperature of the air 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 a closed growing shelter comprises drive means capable of setting the air of the first and second air flows in motion.

[0034] The invention also relates to an installation which comprises a closed growing shelter having an interior volume filled with air, which comprises 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 fluid 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 also relates to a method for dehumidifying air present inside a greenhouse, which comprises regeneration and treatment, in which the regeneration comprises steps in which: a) through a condenser of a refrigeration unit, a first flow of air from an interior volume of the greenhouse is heated, b) using the first air flow heated in step a), a portion to be regenerated of a cyclically regenerating desiccant device is at least partially regenerated, by passing the first air flow through this portion to be regenerated, c) after step b), the first air flow is cooled through an evaporator of the refrigeration unit so that water present in the first air flow condenses in the evaporator to be discharged in liquid form, d) the first air flow from the portion to be regenerated of the desiccant device is conducted to the interior volume of the greenhouse, in which the processing comprises steps in which: e) water is extracted from a second air flow coming from the interior volume of the greenhouse, by passing this second air flow through a desiccating portion of the desiccant device, f) the second air flow is conducted from the drying portion of the desiccant device to the interior volume of the greenhouse.

[0038] In this method, regeneration and treatment are preferably simultaneous. However, this may not be the case. For example, regeneration and treatment may alternate while being able to be momentarily simultaneous over overlapping periods. Furthermore, regeneration may be interrupted momentarily while treatment continues continuously. Similarly, treatment may be interrupted momentarily while generation continues continuously. The choice among these different operating modes may be made to optimize quantities such as the energy efficiency of the dehumidification method according to the invention. Furthermore, at least two of these different operating modes may be combined. Brief description of the figures

[0039] Other advantages and characteristics will emerge more clearly from the following description of several particular embodiments of the invention, given by way of non-limiting example and represented in the appended drawings, among which:

[0040] [Fig-1] is a schematic view of a greenhouse connected to a dehumidifier according to a first 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 subassembly 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 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, steps of the greenhouse dehumidification method which is the subject of the invention. Description of the embodiments

[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 comprises 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 the sake of clarity. This casing and the desiccant wheel 310 together delimit several zones, a regeneration zone of which is located above the dashed line L in [Fig. 3] and a desiccation zone of which is located below the dashed line L in this [Fig. 3].

[0049] A portion 311 of the desiccant wheel 310 to be regenerated is located in the regeneration zone. A desiccant portion 312 of the desiccant wheel 310 is located in the desiccant zone. The desiccant wheel 310 is capable of being pivoted 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 zone drying, at the same time as a portion of the desiccant wheel 310 is passed from the drying zone to the regeneration zone.

[0050] The desiccant wheel is traversed from one side to the other 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 comprises a first circuit 315 for transporting a first air flow in a predetermined direction, which is symbolized by the direction of the arrows representing this first circuit 315 in [Fig.3].

[0052] The first circuit 315 comprises an inlet 316 which is connected to the interior volume of a closed growing shelter which is a greenhouse 301 in the example shown. A condenser 317 for heating the first air flow 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 crossed by the first air flow.

[0054] The condenser 317 is part of a cooling unit which also comprises an evaporator 318 for cooling the first air flow. In a manner known per se, this cooling unit may also comprise a compressor (not shown) and an expansion valve (not shown), which connecting conduits (not shown) connect to the condenser 317 and to the evaporator 318 in a closed circuit containing a refrigerant fluid.

[0055] In the first embodiment described above, the refrigeration unit is a compression-type heat pump. The refrigeration unit may 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, and this in two places so as to put the first air flow into heat exchange relation with itself. More precisely, the first air flow circulating from the portion to be regenerated 311 to the evaporator 318 exchanges heat, in the heat exchanger 320, with the first air flow leaving 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 comprises a second circuit 330 for transporting a second air flow. The direction of circulation of the second air flow in the second circuit 330 is symbolized by the direction of the arrows representing this second circuit 330 in [Fig. 3].

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

[0060] In the example shown, the outlet 332 is a connection of the second circuit 330 in the first circuit 315. It follows that the second air flow is mixed with the first air flow 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 distinct and configured to be connected independently of each other to the interior volume of the greenhouse 1. In this case, the second air flow 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 distinct from one another. In variants (not shown), the first and second circuits have a common inlet to be connected to the interior volume of the greenhouse 301.

[0062] The dehumidifier 300 comprises drive means (not shown), capable of setting the air of the first and second air flows in motion. These drive means may comprise a fan common to the first circuit 315 and to the second circuit 330. In the case of such a common fan, one or more valves may be configured to adjust the flow rates of the first air flow and / or the second air flow. The drive means may also comprise several fans, one of which is configured in the first circuit 315 to set the air of the first air flow in motion, and another of which is configured in the second circuit 330 to set the air of the second air flow in motion.

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

[0064] The treatment is a treatment of the second air flow. In this treatment, humid air is taken from inside the greenhouse 301 and entrained into the second circuit 330 to form the second air flow therein. The desiccation portion 312 captures water in the second air flow which passes through it while circulating in the second circuit 330.

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

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

[0067] The air of the first air flow 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 of the first flow of air extracted from the water in this part to be regenerated which it thus regenerates.

[0068] Between the part to be regenerated 311 of the desiccant wheel 310 and the evaporator 318, the air of the first air flow passes through the heat exchanger 320 for the first time, during which it is cooled. The relative humidity of the first air flow increases with its cooling through the heat exchanger 320.

[0069] The air of the first air flow passes through the evaporator 318 after having passed through the heat exchanger 320 only once. When it passes through the evaporator 318, the air of the first air flow is cooled. Water present in the first air flow then condenses in the evaporator 318 and then flows out in the form of condensates 340, which are discharged. The quantity of water condensing in the evaporator 318 from the first air flow is all the greater as this first air flow has been previously cooled in the heat exchanger 320.

[0070] The first air flow 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 of the first air flow passes through the heat exchanger 320 a second time. The air which passes through the heat exchanger 320 the second time is heated by the air which passes through this heat exchanger 320 the first time. By passing through the heat exchanger 320 the second time, the air of the first air flow becomes warmer and its relative humidity decreases.

[0072] After passing through the heat exchanger 320 the second time, the air of the first air flow 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 treatment of the second airflow, the desiccant portion 312 in the desiccant wheel 310 is charged with water. At times, the desiccant wheel 310 is rotated through a certain angle. For example, the desiccant wheel 310 is rotated half a turn at a time, so that the portion to be regenerated 311 and the desiccant portion 312 are no longer the same portions of the desiccant wheel 310. In variants, the desiccant wheel 310 is rotated continuously.

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

[0075] [Fig. 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 dehumidifier 500 is a dehumidifier for a closed growing shelter.

[0076] Like the dehumidifier 300, the dehumidifier 500 comprises air entrainment means. The entrainment means that the dehumidifier comprises 500 may be identical to those of the dehumidifier 300. In the example shown, they comprise 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 comprises 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 fluid in a manner known per se.

[0078] In the following, the dehumidifier 500 is only described in terms of how it differs from the dehumidifier 300. 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 this referenced part on the dehumidifier 300. In this way, the references of the condenser 517 and the evaporator 518 are constructed in particular.

[0079] The condenser 517 is a first condenser. The subassembly 400 comprises a second condenser, which is the condenser referenced 555 in FIGS. 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 comprises 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. In [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] The valves 556 and 557 make it possible to switch the subassembly 400 between the first state and a second state in which the second condenser 555 is substituted for the first condenser 517 in the closed circuit. In this second state, the valve 557 is open, while the valve 556 is closed. The valves 556 and 557 may in particular be solenoid valves controlled by a monitoring and control 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 a closed 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 comprises a branch of bypass 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 is part of switching means, which comprise the valves 556 and 557, as well as other components known per se and not shown for the sake of clarity. By means of these switching means, the dehumidifier 500 is switchable between the first state and the second state.

[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 for 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 first and second modes of operation of the dehumidifier 500.

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

[0092] In the first mode of operation of the dehumidifier 500, the fan 545 is running and drives the air of the first air flow into the first circuit 515. In the first mode of operation of the dehumidifier 500, the fan 546 is running and drives the air of the second air flow 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] Still 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] Again 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 dehumidifier 500 can operate according to its second operating mode.

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

[0099] In the second operating mode of the dehumidifier 500, the fan 546 may be stopped, which is the case in [Fig. 6]. In the second operating mode of the dehumidifier 500, the fan 546 may also be running in order to increase the air circulation rate inside the greenhouse 501.

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

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

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

[0103] In the second mode of operation, the dehumidifier 500 is very effective in dehumidifying air having a temperature between about 10°C and about 25°C.

[0104] The dehumidifier 500 is versatile in that it can operate in the first operating mode to dehumidify air at a temperature between about 0°C and about 10°C, and can operate in the second operating mode to dehumidify air at a temperature between about 10°C and about 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, of the order of 10°C. For example, the ambient temperature may be the ambient temperature in the interior volume of the greenhouse 501, i.e. the temperature of the air 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, of the order of 12°C.

[0107] In the example shown, the capacitor 555 is connected in the first circuit 515 in the second state of the dehumidifier 500 in addition to being in the first state of the dehumidifier 500. In the second operating mode of the dehumidifier 500, the condenser 555 is crossed by the first air flow although 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] In [Fig.7], we observe a particular embodiment of the method 700 for dehumidifying air present inside a greenhouse, the subject of the invention.

[0109] This method 700 comprises a regeneration 705 and a treatment 710.

[0110] Regeneration 705 comprises the following steps: a) a step 715, during which a first flow of air from an interior 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 desiccant device 310, 510 with cyclic regeneration is at least partially regenerated, by passing the first air flow through this portion to be regenerated 311, 511 using the first air flow heated in step a), c) after step 720, a step 725, during which the first air flow is cooled through an evaporator 318, 518 of the refrigeration unit so that water present in the first air flow condenses in the evaporator 318, 518 to be evacuated in liquid form, and d) a step 730, during which the first air flow from the portion to be regenerated (311, 511) of the desiccant device 310, 510 is conducted to the interior volume of the greenhouse 301, 501.

[0111] The processing 710 comprises the following steps: e) a step 735, during which water is extracted from a second air flow coming from the interior volume of the greenhouse 301, 501, by passing this second air flow through a desiccation portion 312, 512 of the desiccant device 310, 510, and f) a step 740, during which the second air flow is conducted from the drying portion 312, 512 of the drying device 310, 510 to the interior 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 air flow 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 air flow 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 crossing thereof), the air of the first air flow 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 air flow 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 crossing thereof), the air of the first air flow is at 2°C and 100% humidity.

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

[0120] The air resulting from the mixing of the first air flow and the second air flow downstream of the 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, i.e. an example of the first operating mode 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 drying portion 512 of the desiccant wheel 510 in the second circuit 530, the air of the second air flow 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 air flow 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 air flow 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 air flow is at 3°C ​​and 100% humidity.

[0127] The air resulting from the mixing of the first air flow and the second air flow downstream of the 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, i.e. 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 air flow is at 11°C and 100% humidity.

[0131] At the outlet of the condenser 555, the air from the single air flow 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, any 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

Claims

1. Dehumidifier (300, 500) for closed growing shelter (301, 501), characterized in that it comprises: - a first circuit (315, 515) for transporting a first air flow in a predetermined direction, - a second circuit (330, 530) for transporting a second air flow, - a desiccant device (310, 510) with cyclic regeneration, a portion to be regenerated (311, 511) of which is positioned in the first circuit (315, 515) to be crossed by the first air flow and a desiccation portion (312, 512) of which for capturing water in the second air flow is positioned in the second circuit (330, 530) to be crossed by the second air flow, - a refrigeration unit comprising a condenser (317, 517) for heating the first air flow and an evaporator (318, 518) for cooling the first air flow, 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. A dehumidifier (300, 500) according to claim 1, which comprises a heat exchanger (320) connected in the first circuit (315, 515) for putting the first air flow in a first section of the first circuit (315, 515) into heat exchange relation with this first air flow 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. A dehumidifier (500) according to claim 1 or 2, - which comprises a bypass branch (560) which passes away from the desiccant device (310, 510) and connects into 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 deactivatable section comprising the desiccant device (310, 510).

4. A 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. A dehumidifier according to one of claims 3 or 4, which comprises 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. A dehumidifier according to claim 5, wherein the first predetermined threshold is selected from a range of about 8°C to about 12°C.

7. A dehumidifier according to 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. The dehumidifier of claim 7, wherein the second predetermined threshold is selected from a range of about 8°C to about 12°C.

9. A dehumidifier according to any one of claims 1 to 8, which comprises drive means (545, 546) capable of moving the air of the first and second air streams.

10. Installation comprising a closed growing shelter (301, 501) having an interior volume filled with air, characterized in that it comprises a dehumidifier according to 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 fluid communication with the interior volume of the closed growing shelter (301, 501).

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

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

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