High energy efficiency air treatment system for temperature and humidity management in a chamber

Abstract

The invention relates to an air treatment system for adjustable temperature and humidity control in a plurality of chambers (2) for producing plants in a controlled environment, characterised in that it comprises: - a combined cold and heat production unit (1); - a plurality of central air treatment units (3), each chamber (2) being provided with at least one central air treatment unit (3); - each central air treatment unit (3) comprising: o an air treatment housing (30), o at least one heat exchanger (52), o hydraulic components for connection to the cold and heat production unit (1) and the components of the air treatment housing (30); o means for controlling the flow rate and the temperature of the air in the air treatment housing (30) and means for controlling the flow rate and the temperature of the water in the air-conditioning components of the housing (30).

Description

High energy efficiency air handling system for temperature and humidity management in an enclosure

[0001] The present invention relates to the field of air treatment, and more particularly to an air treatment system for managing the internal climatic conditions of an enclosure, specifically controlling the temperature and humidity of the air within that enclosure. These parameters must be precisely controllable, both upwards and downwards, according to requirements specific to the objectives assigned to the enclosure, particularly with a view to reducing energy consumption.

[0002] The application context is, in this case, the production of plants in a controlled environment, specifically in enclosures designed for such production because they define a space suitable for maintaining a controlled atmosphere. These enclosures are, broadly speaking, equipped with actuators and sensors that regulate a number of parameters, such as air temperature, humidity, gas flow (air, CO2, etc.), irrigation levels, and the amount of nutrients supplied to the plants being grown. Among these parameters, temperature and humidity are fundamental, as they contribute more than others to the conditions for the harmonious development of the cultivated plants.

[0003] The major challenge of closed-loop thermal regulation in this context concerns the management of latent heat loads. Indeed, since crops emit large quantities of water vapor through evapotranspiration (more than 80% of the water supplied by irrigation is released in this form), it is necessary to remove this water from the ambient air to maintain a constant humidity level, through dehumidification. The invention aims to provide an air treatment solution capable of containing this water within the system, which is then recovered (through condensation) for reuse in irrigation, thus offering a drastic reduction in the water consumption required for the crop, while also limiting the amount of energy needed to recover this water vapor.

[0004] Among the objectives of the invention, particularly for the continuous management of the aforementioned parameters, the energy aspect has been mentioned. This can be further defined by stating that the aim is to use a minimum of energy to manage the widest possible operating range. The system must be able to operate within a broad temperature and humidity range, regardless of the thermal loads and constraints that otherwise result from the typical operation of this type of installation, such as lighting power, plant transpiration, etc. However, the possibility of a wide operating range must not compromise the precision of the regulation of the aforementioned parameters, which must remain stable and consistent.

[0005] In practice, the invention is such that it makes it possible to keep the minimum operating energy at every point of operation of the system, including under partial load, which notably implies the creation of hydraulic circuits - in particular for the production of cold and heat - which are free as much as possible from the pressure losses related to their constituent components and which minimize the heat transfers to be made to compensate for the (sensible and latent) loads emitted within the environment, namely mainly the water vapor emitted by the plants and the heat released by the artificial lighting used for cultivation.

[0006] Existing systems, particularly those used for closed-loop air conditioning based on thermodynamic dehumidification, often suffer from low energy efficiency. This is the case, for example, with so-called "split" gas-fired air conditioning systems combined with a dehumidifier. These systems result in a significant footprint that can be considered prohibitive for the enclosures covered by this invention, and they also release heat into the space, necessitating complex temperature control. Furthermore, these systems present a risk of icing at low temperatures and high relative humidity. Water chiller and heat pump systems also lack a high overall energy coefficient of performance (COP) because they require independent heating and cooling production, leading to redundant electricity consumption.

[0007] Conventional air handling units are not suitable for controlled atmosphere environments because they do not allow for closed-loop production, resulting in water and CO2 losses. Indeed, their operating principle requires air renewal, the energy and economic balance of which is not always favorable compared to the previously mentioned closed-loop technologies.

[0008] Dehumidification systems using alternative techniques, such as desiccant wheel adsorption, require a high-temperature heat source to regenerate the adsorbent medium, which generally necessitates the combustion of a fossil fuel (such as natural gas). Furthermore, these techniques present a significant risk of water contamination and generally do not allow for the recycling of the collected water. Finally, they require an additional means of temperature control, thus increasing the number of air conditioning units and consequently the cost and space required.

[0009] As for known regulation techniques, modulation by thermostat and hygrostat leads to very low precision and significant variations in relative pressure / volume variables, not allowing for optimized operation, at least not to the extent required to operate an enclosure of the type concerned by the invention which requires a fluctuation limited to a few tenths of degrees Celsius and percentages of relative humidity.

[0010] Contrary to the objective of achieving a wide operating range with optimization possible across its entire width, known solutions that ensure stability—for example, modulation using 2- or 3-way valves—only allow control of water flow or temperature within a limited range, without the possibility of optimization across the full temperature and humidity range. This often leads to contradictory control strategies, such as the need to mist water to compensate for excessive latent power, due to the inability to control the ratio between sensible and latent power delivered by a primary heat exchanger (such as a chilled water coil).

[0011] The present invention addresses these shortcomings by implementing, in a combined manner, a high-performance air handling system, efficient heating and cooling production, and thermal management aimed at optimizing fluid circulation (flow rate and temperature of the air and water circulating within the system) throughout the entire installation. The system of the invention aims to ensure a robust compromise between achieving climate control setpoints (temperature and humidity) and the energy consumption of the hydraulic system components (pumps, fans, compressors), while resolving the contradiction imposed by existing systems that require a choice between high energy consumption or, alternatively, the loss of water and CO2 present in the growing system through air renewal.

[0012] For these purposes, the air treatment system of the invention, more specifically designed for the adjustable regulation of temperature and humidity in a plurality of plant production enclosures in a controlled environment, is such that it comprises:

[0013] - a combined heating and cooling production unit comprising a heat pump, a hot water distribution circuit and a cold water distribution circuit;

[0014] - a plurality of air handling units, each enclosure being equipped with at least one air handling unit;

[0015] - each air handling unit comprising:

[0016] O an air handling unit having two openings leading into the interior of the enclosure and two openings leading out of the enclosure, air conditioning components, fixed internal partitions and movable partitioning means cooperating with the fixed partitions and walls of the unit to delimit at least one air conditioning circuit in the unit, each circuit comprising an air inlet opening, at least one fan directing the airflow and an air outlet opening, said air inlet and air outlet openings of the circuit being two of the four openings leading into the interior and out of the enclosure;

[0017] O at least one heat exchanger allowing the recovery of thermal energy from the outside air, capable of using the outside air as a source of thermodynamic energy in order to achieve heating, cooling or dehumidification of the inside air without air exchange between the inside and outside of the enclosure;

[0018] O hydraulic components connecting the hot and cold water distribution circuits of the heating and cooling unit and the components of the air handling unit;

[0019] O at least one control unit for said hydraulic linking components connected to at least one sensor for at least one air parameter in the enclosure;

[0020] O means for controlling the flow and temperature of the air in the air handling unit and means for controlling the flow and temperature of the water in the air conditioning components of said unit.

[0021] The invention is therefore based on a combined heating and cooling unit whose distribution circuits are connected to the air handling units of each enclosure. At all levels, control devices allow for real-time measurement of the system's operating conditions, so that one or more processing and control units receiving these measurements can select, according to algorithms specifically designed for this system, the actions to be taken to best regulate the air conditioning of the production enclosures.In other words, the invention combines a high-performance air handling system capable of using outside air as an energy source without air exchange, efficient heating and cooling production, and thermal management aimed at optimizing the circulation and state of fluids (including, for example, flow rate and temperature) in the system to ensure the best compromise, continuously, between meeting climate setpoints (mainly temperature and humidity) in the enclosures and energy consumption by the system components (pumps, fans, compressors).

[0022] The implementation of this combined architecture allows for a wide operating range of climate parameters, regardless of the system's thermal loads. It also leads to high control accuracy, resulting in stability and homogeneity of the climate parameters managed by the system. Finally, energy efficiency is significantly increased compared to known systems, leading to minimal energy consumption at any operating point (including under partial load). Due to the proposed configuration, the invention largely eliminates the pressure losses required to balance a large, multi-branch network (at valves, etc.). System optimization is multifaceted and also incorporates heat emission considerations, as it prevents heat input into enclosed spaces.

[0023] Preferably, according to the invention, the movable partitioning means may comprise, on the one hand, at least one partially retractable partition capable of separating a first space having two openings leading to the outside of the enclosure from a second space having two openings leading to the inside of the enclosure, and on the other hand, at least one partially retractable partition capable of separating the openings of the same space. Thus, it is possible to adapt the operating mode of the air handling unit to the internal conditions (operating range of the thermal regulation) and external conditions (surrounding climatic conditions), in order to choose the configuration offering the best compromise in terms of energy consumption, at any time of year and according to the geographical location of the plant production facility.

[0024] The operational regulation mentioned earlier therefore concerns not only the control components such as sensors for the climatic parameters tested during the process, or the software units for processing these parameters, or even the actuator components for coupling the various hydraulic circuits (valves) and their management programs, but also the ability to configure the processing circuits for these climatic parameters in several ways, in order to optimize the implementation of the components best suited to each situation. Changes to the circuits are made via movable partitions whose positions can be modified, as can their degree of closure if it is necessary to partially utilize passageways.

[0025] In a preferred configuration that allows for optimal implementation of air handling system changes, the air inlet of the first space is positioned coaxially with the air outlet of the second space, and vice versa. Under this configuration, the two spaces are arranged in a way that is both opposite and aligned, making it easy to modify the location of the movable partitions to alter the nature and layout of the hydraulic air handling circuits.

[0026] More specifically, the first space may include a fixed internal partition dividing it into two parallel corridors opening into the openings of said first space and connected to each other, near a partition wall that is at least partially retractable, by means of a movable partition. In this design, a first corridor opening into the air intake may, according to the invention, include a fan and a heat exchanger. The first space has a U-shaped volumetric configuration, with the possibility of opening or closing the air passage between the two corridors at the base of the U.

[0027] Similarly, the second space may also include a fixed internal partition dividing it into two parallel corridors opening onto the openings of said second space and connected to each other, near a partition wall that is at least partially retractable, by a passage that can be closed off using movable partitioning devices. Again, a first corridor opening into the air intake may include a fan and a heat exchanger positioned downstream of the fan. This heat exchanger is either connected by a pipe carrying a heat transfer fluid to the heat exchanger of the first space, or it is composed of regularly spaced fins so that the air from the first and second spaces circulates between these fins, allowing for airtight heat exchange, with the airflows crossing without ever mixing.In this configuration, the second corridor can include a cooling coil, a heating coil, and a humidifier proximal to the air outlet opening.

[0028] The relationship between the heat exchangers in the first and second chambers allows for manipulation of the temperature difference between the outside and inside air. For example, it enables the extraction of heat / cooling from the outside air and its transfer to the inside air (or vice versa) via the heat transfer fluid. This allows for sensible and latent heat transfer without air exchange, thus minimizing the impact on overall climate control. As needed, the outside air contributes to heating, cooling, and / or dehumidifying the inside air, reducing the need for a refrigeration or heating unit (and therefore the associated electricity consumption) to perform the heat exchange necessary for climate control within the enclosure.

[0029] Mobile partitioning systems allow for changing the nature of circuits through a physical reconfiguration, depending on the presence or absence of partition walls, which may be retractable. The following configurations, for example, can be implemented:

[0030] - the two spaces are separated by a watertight central partition, and the two corridors of each of the two spaces are connected;

[0031] - the entrance opening of the first space is connected to the exit opening of the second space inside the enclosure, and the entrance opening of the second space is connected to the exit opening of the first space leading to the outside of the enclosure, the two corridors of each space are separated by a watertight partition;

[0032] - the two spaces are separated by a sealed central partition, and the two corridors of the first space connected to the outside air are separated by a sealed partition;

[0033] - the two corridors of the first space connected to the outside air are separated by an airtight partition, and the partitions between the two spaces and the partition between the two corridors of the second space connected to the air inside the enclosure are at least partially retracted.

[0034] All these distinct configurations allow for different operating modes, which will be explained in more detail later. It is immediately clear, however, that the airflow and exchange they enable can significantly alter the climatic parameters inside each chamber. This, combined with the precise management of the system's climatic and hydraulic components, allows for different operating modes that optimize energy consumption and heat and gas exchange between the inside and outside of each growing chamber.

[0035] The components, actuators, etc., are themselves, as already mentioned, managed by processing units coupled with sensors so that, within the climate chambers, all these components ensure system regulation by optimizing its operating point at every moment according to the objective pursued. In practice, in the second space connected to the chamber's interior air, the cooling coil includes at least one air / water heat exchanger for cooling and dehumidification connected to the cold water distribution circuit, and the heating coil includes at least one air / water heat exchanger for heating connected to the hot water distribution circuit. These connections to the hot and cold water distribution circuits themselves include components for adjusting to the desired operating conditions.

[0036] More specifically, according to the invention, the hydraulic components connecting the hot and cold water distribution circuits of the heating and cooling unit and the components of the air handling unit of each air handling unit may include:

[0037] - in a connection pipe to the cold water distribution circuit, a three-way valve and a recirculation pump controlled by a control unit linked to the air handling unit; and

[0038] - in a connecting pipe to the hot water distribution circuit, a two-way valve controlled by said control unit.

[0039] Preferably, the three-way valve, the recirculation pump and the two-way valve are controlled proportionally, proportional control being understood as opposed to an "on or off" control: this means that the opening of the valve and the flow rate / rotation speed of the pump are modulated between 0 and 100% of their maximum value, which implies a possibility of total modulation.

[0040] The air / water cooling and dehumidification exchanger features individualized air and water flow and temperature control for each growing chamber. Regulation is achieved via the invention's control unit, which is based on at least one management algorithm specific to the invention. These algorithms control, in particular, the circulation pump (flow rate, temperature differences) and the 3-way regulating valve (adjusting the water temperature at the chilled coil inlet) in order to optimize the operating point of the air conditioning system according to sensible and latent loads and the required climate setpoints.The control systems manage the various components, seeking an optimum through an algorithm designed to position the cooling coil at the optimal point in terms of the sensible power / latent power ratio. This is achieved by varying the combined flow rate of the water in the cooling coil, the temperature of the incoming cold water, and potentially the air temperature. Consequently, the need for supplemental heating or misting is minimized, reducing cooling power consumption and water input to the enclosure. This ensures dehumidification at the lowest energy cost while reducing water requirements. The air-to-water heat exchanger, connected to the heating and cooling unit, for example via a two-way valve, utilizes total heat recovery to limit the heat pump's energy consumption.

[0041] In the system of the invention, upstream, the hot water distribution circuit of the heating and cooling unit includes at least one water pipe connected by an exchanger to the condenser of the heat pump, and the cold water distribution circuit includes at least one water pipe connected by an exchanger to the evaporator of the heat pump.

[0042] According to a specific aspect of the invention, the heat pump used actually comprises at least one external evaporator-condenser connected to an external heat source, consisting of a heat exchanger with two independent cooling and heating circuits sharing the same cooler. This configuration allows for the fully controllable removal of either excess heat or excess cold to ensure minimal energy consumption (compressor, fan, and pump operation) by utilizing both the cold and hot sources of the thermodynamic circuit represented by the heat pump, thus avoiding redundant electricity consumption associated with the use of two separate heat pumps.

[0043] This is in fact a thermodynamic heat pump circuit allowing the combined, independent and optimized production of cold and heat, making it easy to dose the power exchanged not only with the downstream cold or hot water distribution circuits, but also with the outside (excess cold or heat rejection).

[0044] The heat pump of the cold and heat production unit includes means for controlling the operation of the evaporator-condenser respectively as an evaporator or as a condenser, said control means including means for processing the demand for hot or cold water by the air handling units of the culture chambers.

[0045] The operating principle is as follows: when cooling demand is predominant, the system modulates the compressor speed and the expansion to the evaporator to deliver the required cooling capacity to the distribution side. Depending on whether or not there is a heating demand on the distribution side, the system modulates the condensation between the outdoor evaporator-condenser (operating in condenser mode) and the condenser on the hot water distribution side to dissipate all excess heat. When heating demand is predominant, the reverse occurs: the system adjusts the power delivered for hot water distribution and controls the expansion between the cooling side and the outdoor unit (which then operates in evaporator mode) to dissipate all excess cooling.The transition from one mode to another is gradual, without interrupting the operation of the compressor or reversing the direction of fluids in a circuit, which avoids the use of a cycle reversing valve, and results in improved reliability and a reduced risk of leakage.

[0046] It should be noted that the outdoor evaporator-condenser(s) can be integrated into the machine or located remotely. Furthermore, it should be noted that the outdoor evaporator-condenser(s) can be connected to the compressor circuit either directly (the refrigerant being the one circulating through the compressor) or via a heat exchanger, allowing the use of a different fluid between the compressor circuit and the outdoor evaporator-condenser circuit(s), such as CO2 or another refrigerant for the former and water for the latter. This allows for adaptation to the practical constraints related to the installation (safety, external temperature conditions, network lengths, etc.).

[0047] It should also be noted, from a structural point of view, that the hot water distribution circuit and the cold water distribution circuit each include at least one recirculation pump, ensuring that the distribution of hot and cold water can be carried out under optimal conditions. These recirculation pumps can operate at fixed or variable speed to add a level of energy optimization to the system by adapting the flow rate in the primary hydraulic circuits to the flow rates consumed by the downstream air handling unit(s).

[0048] Other objects and advantages of the present invention will become apparent in the following description, which relates to an embodiment given only by way of example. Understanding this description will be particularly facilitated by reference to the figures attached hereto, in which:

[0049] shows a general diagram of the installation for a site composed of a plurality of climatic chambers;

[0050] represents a schematic diagram of the multifunctional heat pump of the cold and heat production unit;

[0051] schematically illustrates the configuration of an air handling unit; and

[0052] illustrates the operating modes of the power plants with reference to a central diagram representing the main climate parameters managed, temperature and air humidity.

[0053] Lamontre describes the various elements constituting the air treatment system of the invention, namely mainly the heating and cooling unit 1 based on a heat pump and connected to climatic chambers 2 each comprising an air handling unit 3. These are in practice connected to the heating and cooling unit 1 via a hot water distribution circuit 4 and a cold water distribution circuit 5 respectively connected to the hot and cold sides of the heating and cooling unit 1. Inside the climatic culture chambers 2, the regulating devices or elements enabling regulation by optimizing the operating point are mainly a cooling coil, a heating coil, a fan and a humidifier (their relative arrangement will be seen in more detail later).A three-way solenoid valve 6 and a recirculation pump 7 in the cold water distribution circuit 5, and a two-way solenoid valve 8 in the hot water distribution circuit 4, upstream of the air handling unit 3, control, in particular, the incoming flow rate of the cold and hot water circuits. These components are controlled (flow rate, flow velocity, etc.) by a control unit 9 (present in each climate chamber 2), for example, a programmable logic controller (PLC), based on information from temperature, humidity, CO2, etc., sensors 10 located in each air handling unit 3 and in each climate chamber 2 for growing plants.

[0054] With reference to the [reference to the relevant document], the design of the heating and cooling unit is based on a thermodynamic heat pump circuit, for example, a water-to-water system, allowing for the combined, independent, and optimized production of heating and cooling. This also allows for easy adjustment of the power exchanged with the heating and cooling sides, i.e., with the hot water distribution circuits 4 and cold water distribution circuits 5, as well as with the outside environment (excess heat or cold discharge). The operating principle, which has been mentioned previously but is reiterated with references to the [reference to the relevant document], is as follows:

[0055] When cooling demand is predominant, the circuit modulates the speed of the CP compressor and the expansion to the EV evaporator to deliver the required cooling capacity. Depending on whether or not there is heating demand, the circuit modulates the condensation between the outdoor evaporator-condenser EEC (operating in condenser mode) and the CD condenser to dissipate all excess heat. Conversely, when heating demand is predominant, the circuit adjusts the heating capacity and controls the expansion between the cooling side and the outdoor EEC evaporator-condenser (which then operates in evaporator mode) to dissipate all excess cooling. The transition between modes is gradual, meaning that the compressor does not stop running or the fluid flow direction is reversed within the circuit.This avoids the need for an additional component in the circuit, namely a cycle reversing valve, which improves the reliability of the system, particularly by reducing the risk of leakage.

[0056] The use of the EEC evaporator-condenser, positioned near the external source (air or groundwater), which is essentially a heat exchanger with two independent refrigeration and heating circuits (liquid / gas) sharing the same cooler (fins and fan), simplifies the design of the refrigeration circuit in combined operation. This allows for the controlled removal of either excess heat or excess cold via a system control unit, ensuring minimal energy consumption (compression compressor rotation + fans and pumps).

[0057] Precise control of the heat exchange on each side is implemented, optimizing operation by adapting the operating regime of the heating and cooling unit 1 to that of the load consisting of the downstream air handling units 3. This also allows for the use of a variable primary flow rate in said unit 1 to maintain a constant temperature difference (ΔT) on both the heating and cooling sides by adapting the primary flow rate to the water flow rates required in the heat exchangers of the air handling unit(s) (3) supplied by it. This helps reduce energy consumption by minimizing pressure losses in the hydraulic circuits and optimizing thermodynamic efficiency.

[0058] In the system of the invention, the combined heating and cooling unit 1 utilizes the principle of a heat pump with total heat recovery to ensure very high-efficiency heating and cooling production (COP > 7). At the outlet, the two distribution circuits 4 and 5 (there may be more) are independent, each equipped with at least one inverter-modulated compressor 11, 12. This ensures temperature stability while eliminating the need for the large buffer volume required by systems using an on / off compressor. Each circuit is also equipped with its own air-cooled condenser and a total heat recovery heat exchanger, and at least one actuator for regulating the power exchanged with each of them.The coupling of the two main circuits (which are reversible) for the distribution of hot water 4 and cold water 5, each consisting of two supply / return pipes to the air handling units 3, is carried out using actuator-type components (for example the 2 or 3-way valves 8 and 6, and the recirculation pump 7).

[0059] A control algorithm running on at least one computer or PLC, constituting at least one control unit, progressively adapts (precisely dosing power) the operation of the compressors, fans, heat exchangers, and pumps to minimize energy consumption. The circulation speed in the primary (internal circuit of the heat pump) and secondary (hot water distribution circuits 4 and cold water distribution circuits 5) circuits is continuously adjusted to achieve an optimal temperature difference (delta T) on the production side (in distribution circuits 4 and 5) while ensuring a flow rate just sufficient to supply the heat exchangers and limiting the pumps' electrical consumption to the bare minimum.

[0060] An example of an air handling unit is shown in Figure 3. The unit is housed in a casing 30 which has two spaces 31 and 32 located on either side of a physical boundary of the climatic chamber 2, represented by vertical dashed lines in the figure. In practice, this is, for example, a wall of said chamber, in which the air handling unit 3 is positioned so that one part of the casing 30 (containing the first space 31) is located outside the chamber 3, while the other part (containing the second space 32) is inside. The part containing the first space 31 has two openings: an air inlet 33 and an air outlet 34. The part containing the second space 32 similarly has two openings: an air inlet 35 and an air outlet 36.Each space 31, 32 also includes a fixed internal partition 37, 38 separating it into two parallel corridors 44, 45; 46, 47 respectively opening into the openings 33, 34 and 35, 36 respectively. The housing 30 of the air handling unit also has movable partitioning means in the form of at least partially retractable walls 40, 41, 42, 43. As will be seen in more detail later, one or more of these partitions can be retracted completely or partially, by means of a mechanical actuator, to allow more or less complete passage of air flows from the inside or outside of the climate chamber, while controlling their trajectory.

[0061] Corridor 44, downstream of the air inlet 33 of the first space 31 connected to outside air, includes a fan 51 and a heat exchanger 52. Corridor 46, downstream of the air inlet 35 of the second space 32 connected to inside air (the air present in the climatic chamber 3), includes a fan 53 and a heat exchanger 54. The heat exchanger 54 is connected to the heat exchanger 52 of the first space by a pipe 55 carrying a heat transfer fluid. Heat / cooling is extracted from the outside air by the heat exchanger 52 and transferred to the inside air (or vice versa) by means of the heat transfer fluid, thus enabling heat transfer without air exchange. Corridor 47 is equipped, from the inside of the second space 32 towards the air outlet opening 36, with a cold coil 56, followed by a hot coil 57 and a humidifier 58.These cold 56 and hot 57 batteries are respectively cooled by the cold water distribution circuit 5 and heated by the hot water distribution circuit 4, for example by means of coils of tubing carrying the cold or hot water.

[0062] In summary, in the air handling units 3 of the invention, two independent and connectable air loops are created, opening onto the inside and outside of the climatic enclosure 2. Energy recovery from the outside and its transmission are carried out by the two additional exchangers 52, 54 (of the type designated by the Anglo-Saxon term around-coil) coupled between the inside and outside by means of a heat transfer fluid circulating in a tube 55 installed between the two exchangers.In the internal air loop of growing chamber 2, which is therefore located in the second internal space 32, the additional heat exchanger 54 is placed upstream of the cooling coil 56. This allows the air to be pre-cooled using the heat exchanger 52 located on the external loop of the first space 31, with significantly greater efficiency (a much wider annual operating range) because it requires a much smaller internal / external temperature difference (< 10K). Furthermore, if required for operation (see below), this maintains decoupling between the two internal and external loops to prevent any air exchange.

[0063] As will be explained in more detail later, there can be an opening between the two loops in certain operating conditions, typically when the energy savings from renewing the indoor air exceed the costs incurred by the loss of humidity and CO2 to the outside. The maximum rate of fresh air injection can be adjusted (from 0 to 100%) to accommodate different operational and thermal constraints. In short, the two air loops—indoor and outdoor—can operate independently, or coupled via the additional heat exchanger to maximize energy recovery without air exchange, or to allow for partial air exchange.

[0064] The air passage circuits can be reorganized using the mobile partitioning means 40, 41, 42, 42, according to requirements, by means of a mechanical actuator (not shown) controlled by the control unit of the air handling unit 3. Four operating configurations are shown in. They are explained below starting with the one that appears at the top right, then successively in a clockwise direction.

[0065] The configuration in the upper right illustrates closed-loop control: it involves the use of three of the four movable walls 40, 41, and 43. The airflow can therefore pass between corridors 46 and 47, and form an internal loop in the second interior space 32, where the air circulates in a closed loop. The presence of wall 43, however, prevents any recirculation of outside air in the first space 31. The cooling coils 56 and 57 provide all the heat dissipation for the return air. This is what appears in the central diagram, where we are in the "closed loop" zone, without any fresh air intake. This configuration can be used when the outside temperature Text is higher than the inside temperature Tint, and the control system requires cooling of the return air, and vice versa, or when humidification is required.

[0066] The configuration in the lower right illustrates another closed-loop control system, which involves the use of two of the four movable walls 40 and 41. The airflow can therefore pass between corridors 46 and 47 and form an internal loop in the second space 32, where the air operates in a closed internal loop. It can also pass between corridors 44 and 45 and form a loop in the first external space 31: the air then also circulates in a closed external loop. The cooling coil 56 and the heating coil 57 provide all the heat dissipation for the return air.This is a configuration that can be used when the outside temperature Text is lower than the inside temperature Tint, and when the outside humidity He is higher than the inside humidity Hi, in order to achieve pre-cooling (noted "freecooling" in the corresponding area of ​​the central diagram) by recovering cooling from the outside air via the exchangers 52 and 54 connected by the tubing 55, and without air exchange between spaces 31 and 32. This configuration makes it possible to limit energy consumption by keeping water vapor and CO2 inside the culture chamber 2.

[0067] In the configuration shown in the lower left, three of the four movable partitions 40, 41, and 42 are partially retracted, allowing partial airflow and partial operation with fresh air (from outside), as shown in the central diagram. The movable partition 43 is present, preventing air circulation between corridor 44 and corridor 45. Airflow can therefore pass from the outside to the inside, via corridors 44 and 47, and also from the inside to the outside via corridors 46 and 45. In other words, the circuits are such that they connect, on the one hand, the external inlet opening 33 and the internal outlet opening 36, and on the other hand, the internal inlet opening 35 and the external outlet opening 34. Air can also circulate between corridors 46 and 47, thus forming a loop in the second internal space 32.This operating mode is used, for example, when the outside humidity (He) is lower than the inside humidity (Hi) and the outside temperature (Text) is less than or equal to the inside temperature (Tint), in the case where the system is controlling a cooling demand. It is also used when the outside humidity (He) is lower than the inside humidity (Hi) and the outside temperature (Text) is greater than or equal to the inside temperature (Tint), in the case where the system is controlling a heating demand. A portion of the air extracted from the outside atmosphere is reinjected before the cooling coil (56) to directly benefit from the lower temperature and humidity of the outside air and thus limit energy consumption.

[0068] In the configuration at the top left, the two movable walls 42, 43 are present, allowing air to pass through and fresh air to operate from the outside to the inside, via corridors 44 and 47, and also from the inside to the outside via corridors 46 and 45. No air passage is possible between corridor 44 and corridor 45 of the first outdoor space 31, and there is also no air circulation between corridor 46 and corridor 47 of the second indoor space 32. This is an operation that is in principle activated manually, in total fresh air ventilation mode (see central diagram), or that can be programmed at different times during the culture cycle in order to achieve regular air renewal allowing, for example, the removal of undesirable compounds present in the atmosphere of the enclosure (ethylene, etc.).The two exchangers 52, 54 function as heat recovery units used to pre-condition the air in certain cases to limit the thermal load on the cold 56 and hot 57 batteries.

[0069] The energy savings enabled by the system of the present invention are significant:

[0070] - thus, with a strategy prioritizing maximum energy savings, the proposed system makes it possible to reduce electricity consumption by 71% compared to an existing installation, at the cost of a water loss representing 86% of the evapotranspiration generated by the culture;

[0071] - with a strategy balancing energy savings and air recycling, electricity consumption is down by 51%, with only 14% water loss.

[0072] The energy efficiency gain is therefore significant and, even in the case where water loss is significant, the economic balance is favorable: the gains made in terms of operating costs more than compensate for the possible additional cost related to any additional equipment that may be required.

[0073] The example configuration shown in the figure should not be considered exhaustive of the invention, which includes variations, for example, in the shape of the air handling units, in the arrangement or number of components, or in the configuration of the hydraulic circuits. Furthermore, the delimitation of the two spaces, respectively interior and exterior, can be achieved in another way, as in the case of a cross-flow plate heat exchanger in which the outside airflow and the extracted or recycled airflows intersect.

Claims

Air handling system for the modular regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment, characterized in that it comprises: a combined heating and cooling unit (1) comprising a heat pump, a hot water distribution circuit (4) and a cold water distribution circuit (5); a plurality of air handling units (3), each enclosure (2) being equipped with at least one air handling unit (3);Each air handling unit (3) comprising: an air handling unit (30) having two openings (35, 36) opening into the interior of the enclosure (2) and two openings (33, 34) opening out of the enclosure (2), air conditioning components, fixed internal partitions (37, 38) and movable partitioning means cooperating with the fixed partitions (37, 38) and walls of the unit (30) to delimit at least one air conditioning circuit within the unit (30), each circuit comprising an air inlet opening, at least one fan (51, 53) directing the airflow and an air outlet opening, said air inlet and air outlet openings of the circuit being two of the four openings (33, 34, 35, 36) opening into and out of the enclosure (2);at least one heat exchanger (52) allowing the recovery of thermal energy from the outside air, capable of using the outside air as a source of thermodynamic energy in order to heat, cool or dehumidify the indoor air without air exchange between the inside and outside of the enclosure (30); hydraulic components for connecting the hot water (4) and cold water (5) distribution circuits of the heating and cooling unit (1) and the components of the air handling unit (30); at least one control unit for said hydraulic components connected to at least one sensor for at least one air parameter in the enclosure (2); means for controlling the air flow and temperature in the air handling unit (30) and means for controlling the water flow and temperature in the air conditioning components of said unit (30). Air handling system for the adjustable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the movable partitioning means comprise on the one hand at least one wall (40; 41) at least partially retractable capable of separating a first space (31) comprising the two openings (33, 34) opening towards the outside of the enclosure (2) from a second space (32) comprising the two openings (35, 36) opening towards the inside of the enclosure (2), and on the other hand at least one wall (42; 43) at least partially retractable capable of separating the openings (35, 35; 33, 34) of the same space (32; 31). Air handling system for the modulable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the air inlet opening (33) of the first space (31) is coaxial with the air outlet opening (36) of the second space (32), and the air outlet opening (34) of the first space (31) is coaxial with the air inlet opening (35) of the second space (32). Air handling system for the adjustable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to one of claims 2 and 3, characterized in that the first space (31) has a fixed internal partition (37) separating it into two parallel corridors (44, 45) opening into the openings (33, 34) of said first space (31) and connected to each other, in the vicinity of a wall (40, 41) at least partially retractable separating it from the second space (32), by a passage closable by means of movable partitioning (43), a first corridor (44) opening into the air inlet opening (33) comprising a fan (51) and an exchanger (52). An air handling system for the adjustable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the second space (32) comprises a fixed internal partition (38) dividing it into two parallel corridors (46, 47) opening onto the openings of said second space (32) and connected to each other, in the vicinity of a partition wall (40, 41) at least partially retractable separating it from the first space (31), by a passage closable by means of movable partitioning (42), a first corridor (46) opening into the air inlet opening (35) comprising a fan (53) and a heat exchanger (54) positioned downstream of the fan (53), said heat exchanger (54) being connected by a pipe (55) carrying a heat transfer fluid to the heat exchanger (52) of the first space (31), the second corridor (47) comprising a cold battery (56),a heating coil (57) and a humidifier (58) proximal to the air outlet opening (36). Air handling system for the modular regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the cold coil (56) comprises at least one air / water cooling and dehumidification exchanger connected to the cold water distribution circuit (5) and the hot coil (57) comprises at least one air / water heating exchanger connected to the hot water distribution circuit (4). Air handling system for the modulable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to any one of the preceding claims, characterized in that the hydraulic linking components between the hot water (4) and cold water (5) distribution circuits of the heating and cooling unit (1) and the components of the air handling unit (30) of each air handling unit comprise: in a connecting conduit to the cold water distribution circuit (5), a three-way valve (6) and a recirculation pump (7) controlled by a control unit (9) linked to the air handling unit (3); and in a connecting conduit to the hot water distribution circuit (4), a two-way valve (8) controlled by said control unit (9). Air handling system for the modular regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the three-way valve (6), the recirculation pump (7) and the two-way valve (8) are controlled proportionally. Air handling system for the modulating regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to one of the preceding claims, characterized in that the hot water distribution circuit (4) of the cold and heat production unit (1) comprises at least one water line connected by an exchanger to the condenser (CD) of the heat pump, and the cold water distribution circuit (5) comprises at least one water line connected by an exchanger to the evaporator (EV) of the heat pump. Air handling system for the modulating regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to one of the preceding claims, characterized in that the heat pump of the cold and heat production unit (1) comprises at least one external evaporative condenser (EEC) connected to an external heat source, consisting of an exchanger having two independent refrigeration and heating circuits respectively sharing the same cooler. Air handling system for the modular regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to the preceding claim, characterized in that the heat pump of the cold and heat production unit (1) includes means for controlling the operation of the evaporator-condenser (EEC) respectively in evaporator or in condenser, said control means including means for processing the demand for hot water or cold water by the air handling units (3) of the enclosures (2). Air handling system for the adjustable regulation of temperature and humidity in a plurality of plant production enclosures (2) in a controlled environment according to one of the preceding claims, characterized in that the hot water distribution circuit (4) and the cold water distribution circuit (5) each include at least one recirculation pump (11, 12).

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