Providing treatment fluids for dialysis therapy

Abstract

The system for providing a process fluid (TF) for dialysis therapy comprises a fluid generator configured to generate the process fluid (TF) by mixing one or more substances with water, and a dehumidifier configured to receive a first air flow, process the first air flow to extract liquid water (EW) and provide the liquid water (EW) for the fluid generator. The system further comprises a humidifier configured to receive a second air flow and process the second air flow to generate a third air flow having increased humidity compared to the second air flow. The humidifier is arranged to include at least a portion of the third air flow in the first air flow. Depending on the configuration, the system can reduce the need for tap water, facilitate installation, facilitate purification, and / or improve the indoor environment.

Description

[Technical field]

[0001] The present disclosure relates generally to dialysis therapy, and more particularly to techniques for producing dialysate for use in dialysis therapy. [Background technology]

[0002] Dialysis therapy may be required to treat individuals suffering from acute or chronic renal failure.

[0003] One category of dialysis therapy is extracorporeal (EC) hemotherapy, in which blood from a patient is pumped back to the patient through an EC blood circuit. A hemofilter (commonly known as a dialyzer) is placed in the EC blood circuit in contact with the blood by a semipermeable membrane. There are various types of EC hemotherapy, including hemodialysis (HD), hemofiltration (HF), and hemodiafiltration (HDF). In HD, a treatment fluid ("dialysate") is pumped through the dialyzer. Water and substances are exchanged between the treatment fluid and the blood through the semipermeable membrane driven primarily by a diffusion gradient across the semipermeable membrane. In HF, the treatment fluid is not pumped through the dialyzer. Instead, during treatment, a treatment fluid ("substitution fluid") is infused into the blood in the EC blood circuit, upstream and / or downstream of the dialyzer, and fluids and substances are transported from the blood through the semipermeable membrane, primarily by convection. In HDF, the dialysate is pumped through the dialyzer as in HD, and the substitution fluid is infused into the blood in the EC blood circuit as in HF.

[0004] Another category of dialysis therapy is peritoneal dialysis (PD). In PD therapy, a treatment fluid ("dialysate") is infused into an individual's peritoneal cavity. This cavity is lined by a highly vascularized peritoneal membrane ("peritoneum"). Substances are removed from the patient's blood primarily by diffusing across the peritoneal membrane into the dialysate. Excess fluid (water) is removed by osmosis induced by the dialysate, which is hypertonic. The spent or used dialysate is drained from the patient, removing waste, toxins, and excess water from the patient. This cycle can be repeated, for example, multiple times. There are various types of PD therapy, including continuous ambulatory PD (CAPD), automated PD (APD), tidal PD (TPD), and continuous flow PD (CFPD). CAPD is a manual dialysis therapy in which the flow of treatment fluid into and out of the patient is driven by gravity. APD is performed by a dialysis machine, commonly known as a cycler, which is fluidly connected to the peritoneal cavity and operates to automatically transfer treatment fluid to and from the peritoneal cavity according to a predetermined schedule, for example, overnight while the patient is sleeping.

[0005] Traditionally, treatment fluids for PD are delivered in pre-filled bags to the point of care, e.g., intensive care units or the patient's home. EC hemotherapy may also use pre-filled bags of treatment fluid, e.g., in intensive care units, for the treatment of acute renal failure. Treatment fluids for the treatment of chronic renal failure by EC hemotherapy are typically produced by the dialysis machine itself, by mixing one or more concentrates with purified water. Recently, dialysis machines that produce treatment fluids for PD treatment have also been proposed.

[0006] Local generation of treatment fluid at the point of care is attractive because it reduces the cost and environmental impact of transporting large amounts of pre-made treatment fluid, as well as the burden of storing and handling pre-filled bags. However, production of treatment fluid requires access to purified water. Typically, a water purifier is connected to a tap water source, and a fluid generator is operated to mix one or more concentrates with the purified water to generate the treatment fluid. Large amounts of tap water may be consumed. In PD therapy, approximately 15 liters of treatment fluid may be consumed daily. In EC hemotherapy, more than 100 liters of treatment fluid may be consumed during a single treatment session.

[0007] To improve the patient's quality of life and to reduce the cost of treatment, dialysis may be performed locally in the patient's home ("home dialysis"). As mentioned above, local generation of treatment fluid requires access to running water and preferably also access to a drain for disposal of used treatment fluid. Thus, installation in the patient's home may include plumbing work to install tubing between the sanitary area and the room where the treatment is performed, e.g., the bedroom. Plumbing work increases treatment costs and, by extending the tubing, increases the risk of leaks and resulting water damage.

[0008] Another obstacle to home dialysis is the need to purify tap water. A water purifier must be installed in the patient's home, either as a separate device or included in the dialysis machine. The water purifier is configured to treat tap water, for example, to ensure that the treated fluid meets quality standards with regard to the content of various ions, molecules, and larger particles, as well as microorganisms. For example, the water purifier may be configured to perform reverse osmosis, which increases the cost of the dialysis system as a whole.

[0009] US10632242 discloses a dialysis machine designed to operate in areas where resources such as energy and clean water are scarce. The dialysis machine includes a condenser-based water generator powered by solar panels to extract water from the ambient air. After passing through an ultrafilter, the extracted water can be mixed with a concentrate to form a dialysate or used to generate a saline solution that is infused into the patient's blood. The dialysate is added as a supplement to the regenerated dialysate, which is generated from spent dialysate by the use of an adsorption device. The amount of extracted water is sufficient to generate a supplement to the regenerated dialysate. However, when operated indoors, the amount of available air is limited, and the proposed dialysis machine generally cannot extract water in the amount required to generate the PD fluid required for the patient's daily PD treatment. Furthermore, extracting a significant amount of water from the air of the indoor environment can reduce humidity to a degree that is uncomfortable or even unhealthy for the patient. Summary of the Invention

[0010] SUMMARY OF THE PRESENT EMBODIMENT It is an object of the present invention to at least partially overcome one or more of the limitations of the prior art.

[0011] One objective is to provide a technique that facilitates dialysis therapy treatment in an indoor environment, such as a patient's home.

[0012] A further object is to provide a cost-effective system for providing treatment fluid for dialysis therapy.

[0013] One or more of these objects, as well as further objects that may become apparent from the following description, are achieved at least in part by a system for providing a treatment fluid for dialysis therapy, and related methods, embodiments of which are defined by the dependent claims.

[0014] A first aspect is a system for providing a treatment fluid for dialysis therapy, the system comprising: a fluid generator configured to generate the treatment fluid by mixing one or more substances with water, a dehumidifier configured to receive a first air flow, process the first air flow to extract liquid water, and provide the liquid water for the fluid generator, and a humidifier configured to receive a second air flow and process the second air flow to generate a third air flow having increased humidity compared to the second air flow, the humidifier configured to include at least a portion of the third air flow in the first air flow.

[0015] The system of the first aspect combines a dehumidifier with a humidifier configured to generate a moist air flow using tap water. This allows the humidifier to increase the available amount of water extracted by the dehumidifier from a given air volume. This makes the system suitable for use in indoor environments where the available air volume may be limited. The provision of a humidifier also makes it possible to maintain acceptable air humidity in such indoor environments, even if the dehumidifier needs to be operated to extract a large amount of water from the air. Even if tap water is required for the operation of the humidifier, the total amount of tap water required by the system to generate a given amount of treatment fluid may be reduced if the dehumidifier is operated to extract water in excess of the water added by the humidifier to the moist air flow. By configuring the system to require a reduced amount of tap water, the need for a fixed installation of tubing is reduced, since tap water is not difficult to manually transfer, for example, from a fixed tap water outlet to a tank of the system.

[0016] The system opens up several possibilities to facilitate installation. In some embodiments, it allows the humidifier and dehumidifier to be physically separated from each other and placed independently in the indoor environment. For example, the humidifier may be placed near a fixed outlet for tap water, and the dehumidifier near the fluid generator. The transfer of water from the humidifier to the dehumidifier is performed by a flow of moist air generated by the humidifier. The flow of moist air may be guided in a tube from the humidifier to the dehumidifier. Such a tube is simple to install and does not significantly increase the risk of water damage, since it conducts gas (air) and not liquid water. Alternatively, no tube is used for air transfer, and the humidifier and dehumidifier are thus completely separated from each other. Instead, a moist air flow is emitted by the humidifier in the immediate vicinity of the humidifier, and the flow of incoming air to be dehumidified is received by the dehumidifier from its immediate vicinity. Over time, as the system operates, at least a portion of the moist air emitted by the humidifier unit is transferred to the dehumidifier unit, for example, by natural and / or forced convection in the indoor environment. The absence of a tube between the humidifier unit and the dehumidifier unit increases the freedom to choose a convenient location of the respective units. In some embodiments, the humidifier unit and the dehumidifier unit are instead combined in a monolithic structure and are thus co-located. The transfer of moist air flow from the humidifier unit to the dehumidifier unit may be performed in any suitable manner within the monolithic structure. The single combination results in a single unit that is compact and suitable for installation in limited spaces such as a home. Furthermore, system control may be facilitated in a system with a single combination of humidifier and dehumidifier units compared to a system with physically separated humidifier and dehumidifier units. In some embodiments, the dehumidifier unit includes a desiccant arranged to adsorb and / or absorb water in the incoming air flow. The desiccant may be in liquid or solid form. The use of a desiccant for dehumidification allows for the extraction of water in a power-efficient manner. Furthermore, water can be efficiently extracted from air that holds less moisture compared to condenser-based dehumidification. In some embodiments, by proper selection of the desiccant, the dehumidifier performs inherent purification of the extracted water.Purification is achieved by ensuring that the desiccant has high selectivity for water, and therefore preferentially adsorbs and / or absorbs water molecules compared to other molecules, as well as ions and particles, present in the incoming gas stream. Such a dehumidifier has the potential to replace or supplement water treatment units that may be required for the production of conventional process fluids. For example, water treatment by reverse osmosis can be eliminated, saving costs.

[0017] In some embodiments, the dehumidifier comprises a desiccant arranged to adsorb and / or absorb moisture from the first air flow and treated by the dehumidifier to extract the liquid water from the desiccant.

[0018] In some embodiments, the desiccant is configured to be highly selective for water.

[0019] In some embodiments the liquid water extracted from the first air stream has a conductivity of less than 10 μS / cm, preferably less than 5 μS / cm, or less than 1 μS / cm.

[0020] In some embodiments, the system further comprises a control device configured to jointly operate the humidifier and dehumidifier units to achieve a set point defining the air humidity within a space comprising the humidifier and dehumidifier units.

[0021] In some embodiments, the controller is further configured to operate the dehumidifier to achieve a set point defining an amount of liquid water extracted per unit time.

[0022] In some embodiments, the controller is further configured to deactivate the humidifier and the dehumidifier if the accumulated amount of liquid water exceeds a threshold.

[0023] In some embodiments, the system further comprises at least one humidity sensor configured to generate a measurement signal representative of the air humidity in the space.

[0024] In some embodiments, the control device is configured to perform a step response test by inducing a step change in operational performance of at least one of the humidifier unit or the dehumidifier unit, monitor the measurement signal, and determine a control parameter value for the control device based on the measured air humidity in the space as a function of time following the step change.

[0025] In some embodiments, the at least one humidity sensor is configured to measure the air humidity in at least one of the first air stream and the second air stream.

[0026] In some embodiments, the system further comprises a connection sensor configured to sense a fluid connection status between the humidification unit and the dehumidification unit, and the control device is operable to modify operation of the control device in response to the fluid connection status sensed by the connection sensor.

[0027] In some embodiments, the system further comprises at least one fluid connection device between the humidifier unit and the dehumidifier unit, the humidifier unit configured to emit at least a portion of the third air flow into the at least one fluid connection device, and the dehumidifier unit configured to receive the first air flow from the at least one fluid connection device.

[0028] In some embodiments, the humidifying section and the dehumidifying section are combined into a unitary structure.

[0029] In some embodiments, the dehumidification unit is configured to output a fourth air flow generated when the first air flow is treated to extract the liquid water, and the system further defines a fluid path configured to redirect at least a portion of the fourth air flow to an air inlet of the humidification unit and to include the at least a portion of the fourth air flow in the first air flow.

[0030] In some embodiments, the fluid pathway is arranged to redirect the fourth air flow to the air inlet of the humidifier such that the fourth air flow forms the first air flow.

[0031] In some embodiments, the system comprises a flow controller operable to set the amount of the fourth air flow redirected to the air inlet of the humidifier.

[0032] In some embodiments, the system is switchable between a first operating mode and a second operating mode by operation of the flow controller, and in the first operating mode, the system is configured to admit ambient air into the second air flow and to supply at least a portion of the fourth air flow to the ambient air, and in the second operating mode, the system is configured to direct the fourth air flow to the air inlet of the humidifier, whereby the fourth air flow forms the first air flow.

[0033] In some embodiments, the system is configured to provide all of the fourth air flow to the ambient air in the first mode of operation.

[0034] In some embodiments, the system comprises an inlet line connected to the air inlet of the humidifier unit, and an outlet line connected to the outlet of the dehumidifier unit and receiving the fourth air flow from the dehumidifier unit, the fluid pathway being fluidly connected at a first junction on the outlet line and a second junction on the inlet line, and the flow controller configured to control the air flow rate through the fluid pathway from the outlet line to the inlet line.

[0035] In some embodiments, the humidifier is configured to emit the third air flow into ambient air and the dehumidifier is configured to receive the first air flow from the ambient air.

[0036] In some embodiments, the humidification section is physically separated from the dehumidification section.

[0037] In some embodiments, the humidifier is configured to receive tap water and treat the tap water to generate the second air flow and the third air flow from the tap water.

[0038] In some embodiments, the humidifier unit is connected to receive the tap water from a tank, and the system is configured to estimate a time point of depletion of the tank based on a signal from a level sensor in the tank or based on measured air humidity in a space comprising the humidifier unit and the dehumidifier unit, and to output a user instruction to add tap water to the tank prior to said time point.

[0039] In some embodiments, the system is configured to estimate the point of depletion by using a computational model configured to predict the extraction of the liquid water (EW) as a function of air humidity, and further by using data indicative of consumption of the treatment fluid (TF) by an operational treatment system connected to receive the treatment fluid (TF) from the system.

[0040] In some embodiments, the system further comprises a reservoir configured to receive and accumulate the liquid water from the dehumidifier or the treatment fluid from the fluid generator.

[0041] A second aspect is a method of providing a treatment fluid for use in dialysis therapy, the method comprising: treating a first air stream to extract liquid water, producing the treatment fluid by mixing at least a portion of the liquid water with one or more substances, treating a second air stream to produce a third air stream having increased humidity compared to the second air stream, and including at least a portion of the third air stream in the first air stream.

[0042] A third aspect is a computer-implemented method of operating the system of the first aspect or any of its embodiments, the method including receiving at least one measurement signal representative of air humidity in a space comprising the humidifier and dehumidifier units, and cooperatively operating the humidifier and dehumidifier units to achieve a predetermined air humidity in the space as indicated by the at least one measurement signal.

[0043] An embodiment of the first aspect may be adapted as an embodiment of the second or third aspect.

[0044] A fourth aspect is a computer readable medium comprising program instructions that, when executed by a processor, cause the processor to perform the method of the second or third aspect, or any embodiment thereof. The computer readable medium may be a non-transitory medium or a propagating signal.

[0045] Further objects, aspects, embodiments, and technical effects, as well as features and advantages, may become apparent from the following detailed description, the appended claims, and the drawings. [Brief description of the drawings]

[0046] In the following, embodiments will be explained in more detail with reference to the accompanying drawings and schematic diagrams.

[0047] [Figure 1A] FIGS. 1A-1B are schematics of an exemplary dialysis system for peritoneal dialysis and extracorporeal blood treatment, FIG. 1C is a more detailed block diagram of an exemplary dialysis system including a combined humidifier and dehumidifier unit, and FIGS. 1D-1F are block diagrams of an exemplary fluid generator unit, an exemplary humidifier unit, and an exemplary dehumidifier unit for use in the dialysis system of FIGS. 1A-1B. [Figure 1B] Same as above [Figure 1C] Same as above [Figure 1D] Same as above [Figure 1E] Same as above [Figure 1F] Same as above [Figure 2A] FIG. 2A is a side view of a non-connected humidifier and dehumidifier combination, and FIG. 2B is a plan view of a home environment including an example installation of the non-connected combination. [Figure 2B] Same as above [Diagram 3] FIG. 3 is a flow chart of an exemplary method of installing and operating a combination humidifier and dehumidifier. [Figure 4] FIG. 4 shows a floor plan of a domestic environment including an example installation of a connected combination of humidifier and dehumidifier units. [Figure 5A] 5A-5D are block diagrams of connected combinations of humidifier and dehumidifier units according to various embodiments. [Figure 5B] Same as above [Figure 5C] Same as above [Figure 5D] Same as above [Figure 6] FIG. 6 is a flow chart of a method of installing and operating the combination of FIG. 5C. [Figure 7A] 7A-7D show humidifier and dehumidifier units that can operate in either an unconnected combination or a connected combination. [Figure 7B] Same as above [Figure 7C] Same as above [Figure 7D] Same as above [Figure 8] FIG. 8 is a flow chart of a method for providing a processing fluid.

[0048] List of abbreviations APD automated peritoneal dialysis CAPD continuous ambulatory peritoneal dialysis CPD Continuous Flow Peritoneal Dialysis DHU dehumidification section DIA Inlet air flow (dehumidification section) DOA Outlet air flow (dehumidification section) EC in vitro EW Extracted Liquid Water FCD Fluid Connection Device FGU fluid generation section FPS Fluid Preparation System Ha Ambient humidity HD Hemodialysis HDi inlet humidity (dehumidification section) HDF Hemodiafiltration Hdo outlet humidity (dehumidification section) HF hemofiltration Hhi Inlet humidity (humidifying section) Hho Outlet humidity (humidifying section) HIA Inlet air flow (humidification section) HOA Outlet Air Flow (Humidification Section) HU humidifying section MOF metal organic framework PC peritoneal cavity PD peritoneal dialysis RH Relative Humidity RO Reverse Osmosis SBU Secondary structural unit TPD Tidal peritoneal dialysis TW Tap water Detailed Description of the Embodiments DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

[0050] It will also be understood that, where possible, any of the advantages, features, functions, apparatus, and / or operational aspects of any of the embodiments described and / or contemplated herein can be included in any of the other embodiments described and / or contemplated herein, and / or vice versa. Furthermore, where possible, any term expressed in the singular herein is meant to include the plural and / or vice versa, unless expressly stated otherwise. As used herein, "at least one" means "one or more," and these phrases are intended to be interchangeable. Thus, the terms "a" and / or "an" shall mean "at least one" or "one or more," although the phrases "one or more" or "at least one" are also used herein. As used herein, unless the context otherwise requires to express the words or necessary implication, the words "comprise" or variations such as "comprises" or "comprising" are used in an inclusive sense, i.e., to specify the presence of the stated features, but not to preclude the presence or addition of additional features in various embodiments.

[0051] As used herein, the terms "plurality," "plurality," and "plurality" are intended to mean the provision of two or more elements, whereas the term "collection" of elements is intended to mean the provision of one or more elements. The term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0052] Furthermore, it should be understood that although terms such as first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another element. For example, a first element can be called a second element, and similarly, a second element can be called a first element, without departing from the scope of the present disclosure.

[0053] Well-known functions or configurations may not be described in detail for brevity and / or clarity.Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0054] As used herein, "dialysis therapy" refers to any therapy that replaces or supplements a patient's kidney function through the use of a treatment fluid. Dialysis therapies include, but are not limited to, extracorporeal blood therapy and peritoneal dialysis therapy.

[0055] As used herein, "process fluid" refers to any fluid consumed as a result of dialysis therapy, including, but not limited to, dialysate, replacement fluid, and substitution fluid.

[0056] As used herein, "ambient air" or "outside air" refers to air that is within a confined space, such as an apartment building, a room, etc., but is outside the system described herein. When referring to a flow of air being received from the surroundings, the flow of air is taken from the surroundings. Similarly, when referring to a flow of air being released into the surroundings, the flow of air is included in the surroundings.

[0057] Like numbers refer to like elements throughout.

[0058] The present disclosure relates to techniques for generating treatment fluids for dialysis systems. The techniques are applicable to both peritoneal dialysis (PD) therapy or extracorporeal (EC) blood therapy. For context purposes only, fluid generation associated with PD treatment and EC blood therapy will be briefly described with reference to FIGS. 1A-1B.

[0059] FIG. 1A is a general schematic of a dialysis system for PD treatment. The dialysis system includes a treatment system 10 that is fluidly connected to the peritoneal cavity PC of a patient P. As indicated by the double-headed arrow, the treatment system 10 is operable to deliver fresh treatment fluid into the peritoneal cavity PC and to receive spent treatment fluid from the peritoneal cavity over fluid path 11. The fluid path 11 may be defined by a tube that connects to an implanted catheter (not shown) that is in fluid communication with the peritoneal cavity PC. The treatment system 10 may be configured for any type of PD treatment. In one example, the treatment system 10 includes one or more containers that are manually handled to perform CAPD. In another example, the treatment system 10 includes a dialysis machine ("cycler") that performs dialysis therapy. The dialysis system further includes a fluid preparation system FPS 20 configured to generate treatment fluid for use by the treatment system 10. The treatment fluid is delivered from the FPS 20 to the treatment system 10 over fluid path 12. The spent treatment fluid may be handled by the treatment system 10 or may be transported for handling by the FPS 20. The spent process fluid may be stored, reclaimed, or sent to a drain, or any combination thereof.

[0060] FIG. 1B is a general schematic of a dialysis system for EC blood therapy. The dialysis system comprises a treatment system 10 fluidly connected to the vascular system of a patient P on a fluid pathway. In the illustrated example, the fluid pathway is defined by a tube 11A for blood extraction and a tube 11B for blood return. As indicated by the arrows, the treatment system 10 is operable to draw blood from the patient P through the tube 11A, process the blood, and return the processed blood to the patient through the tube 11B. The tubes 11A, 11B are connected to an access device (e.g., a catheter, graft, or fistula, not shown) in fluid communication with the vascular system of the patient P. The treatment system 10 may be configured to process blood by any form of EC blood therapy, such as HD, HF, or HDF. In such treatments, a treatment fluid is consumed. The treatment fluid is supplied to the treatment system 10 on a fluid pathway 12 from the FPS 20. The spent treatment fluid may be handled by the treatment system 10 or may be transported for handling by the FPS 20. The spent process fluid may be stored, reclaimed, or sent to a drain, or any combination thereof.

[0061] FIG. 1C shows the dialysis system, in particular the FPS 20, in more detail. According to some embodiments, the FPS 20 comprises a humidification unit HU21 and a dehumidification unit DHU22. The HU21 is arranged to receive tap water TW on a fluid path 30' from a tap water source 30. The tap water source 30 may be a permanent outlet (tap, tap, spigot, etc.) or a tank, and is refilled with tap water manually or automatically as needed. The HU21 is configured to generate a moist air flow based on the TW. The DHU22 is configured to extract liquid water EW from the incoming air flow. As will be explained in more detail below, a fluid path 21' is established between the HU21 and the DHU22, so that at least a portion of the moist air flow is included in the incoming air flow to the DHU22. At least a portion of the EW extracted by the DHU22 thereby corresponds to the TW received and processed by the HU21. In some embodiments, fluid pathway 21' comprises one or more enclosed (physical) paths and is defined by a connection device extending between HU 21 and DHU 22. In other embodiments, fluid pathway 21' is established by HU 21 releasing a flow of humidified air into the surrounding air.

[0062] In the example of FIG. 1C, the EW is transferred from the DHU 22 to a reservoir 23 on a fluid path 22′. The reservoir 23 is a tank, container, or the like for intermediate storage of the EW. The fluid path 23′ extends from the reservoir 23 to a fluid generator FGU 24. The FGU 24 is configured to prepare a treatment fluid TF by mixing the EW with one or more substances, for example in the form of one or more concentrates. The TF is then supplied to the treatment system 10 on the fluid path 12. The reservoir 23 allows the production of the EW to be decoupled from the production of the TF, which may simplify the FGU 24. Furthermore, the reservoir 23 allows the system to use a portion of the EW to clean the treatment system 10 and / or the FPS 20. For example, a certain daily drainage volume may be required to counter scaling of the HU 21. Alternatively, reservoir 23 or an additional reservoir (not shown) is configured to receive TF from FGU 24, and TF is provided from reservoir 23 or the additional reservoir to treatment system 10. In a further alternative, reservoir 23 is omitted.

[0063] The division into FPS 20 and treatment system 10 is arbitrary and is done for illustrative purposes only. Figure 1C shows an alternative division that will be used in some examples below (Figures 2B and 4). In this alternative division, the dialysis system comprises a combined treatment system 10' including HU 21, DHU 22, and treatment system 10, FGU 24, and reservoir 23 (if present). In practice, HU 21, DHU 22, reservoir 23, FGU 24, and treatment system 10 may be separate devices or may be structurally combined in any suitable manner.

[0064] FIG. 1D is a schematic diagram of the FGU 24. FIG. 1D is intended merely to illustrate the overall functionality of the FGU 24 and is not intended to be limiting in any manner. In the illustrated example, the FGU 24 is positioned to receive EW from the reservoir 23 on the fluid path 23′. If the reservoir 23 is omitted, the FGU 24 receives EW from the DHU 22 on the fluid path 22′. The FGU 24 comprises a mixing section 241 configured to mix the EW with one or more concentrates, represented in FIG. 1D as F1, ..., Fn. Each concentrate F1, ..., Fn may be in liquid or powder form. The concentrates are held in a reservoir 242 and delivered to the mixing structure 241 on a path 243. The EW is mixed with one or more concentrates F1, ..., Fn in the mixing structure 241 to form TF, which is delivered to the treatment system 10 on the fluid path 12. The mixing structure 241 may be of any conventional configuration. It should be understood that the FGU 24 may include additional equipment such as devices for dosing concentrates and EW, devices for mixing, heating devices, degassing devices, pumps, sensors, etc. Any available concentrates conventionally used to generate treatment fluids for PD therapy or EC blood therapy by mixing with water may be used. The FGU 24 may be configured to generate TF in batches or on demand. In on-demand generation, the amount of TF produced is adapted or matched to the amount of TF consumed by the treatment system 10.

[0065] In some embodiments, TF for use in EC blood therapy of patients with chronic kidney disease (CKG) is produced by mixing a single concentrate with water at a dilution ratio of 10-50 by volume. In a non-limiting example, the single concentrate includes lactate, sodium, potassium, calcium, magnesium, glucose, and chloride. Such concentrates are commercially available, for example, from NxStage for the PureFlow SL system. Alternatively, TF can be produced by mixing two concentrates with water. For example, a base concentrate and an acid concentrate can be mixed with water at a dilution ratio of 10-50. Such concentrates are commercially available and well known in the art. In a non-limiting example, the base concentrate includes a buffer, e.g., bicarbonate, and the acid concentrate includes sodium, potassium, calcium, magnesium, glucose, acetate, and chloride. In some acid concentrates, acetate is replaced or supplemented by another acid, e.g., citric acid. In some embodiments, TF for CRRT treatment of patients with acute kidney injury (AKI) is produced by mixing at least one concentrate with water. In non-limiting examples, such dialysis / substitution fluids include bicarbonate, sodium, potassium, calcium, magnesium, phosphate, glucose, acetate, and chloride. In one example, a base concentrate and an electrolyte concentrate can be mixed with water to form the dialysis / substitution fluid. For example, the base concentrate can be an alkaline bicarbonate solution and the electrolyte concentrate can be an acidic glucose-based electrolyte solution.

[0066] TF for use in PD treatment can be produced by mixing at least one concentrate with water. Exemplary compositions of concentrates to be mixed with water are disclosed in US2018 / 0021501 and WO2017 / 193069, which are incorporated herein by reference. In one example, one or more concentrates include ions and / or salts such as lactate, acetate, citrate, bicarbonate, KCl, MgCl2, CaCl2, NaCl, and an osmotic agent. In any of the embodiments described herein, the osmotic agent may be or include glucose (or polyglucose), L-carnitine, glycerol, icodextrin, or any other suitable agent. For example, icodextrin is a glucose polymer preparation commonly used as an osmotic agent in PD fluids. Alternative osmotic agents may be fructose, sorbitol, mannitol, and xylitol. It is noted that glucose is sometimes referred to as dextrose in the PD field. The term "glucose" as used herein is intended to include dextrose.

[0067] FIG. 1E is a block diagram of an exemplary humidifier HU21. The evaporator 210 is configured to evaporate (vaporize) TW to generate gaseous moisture and add at least a portion of the gaseous moisture to the inflow air flow HIA. This generates a humidified outflow air flow HOA. The evaporator 210 may be of conventional design. In some embodiments, the evaporator 210 is configured to process TW by applying heat, optionally at low pressure, to generate gaseous moisture. The HU21 of FIG. 1E comprises an air inlet 21A, an air outlet 21B, and a tap water inlet 21C. The air inlet 21A opens into an air inlet path 211 that extends to the evaporator 210. An air filter 212 is disposed in the air inlet path 211 to remove particulate matter such as debris, dust, etc. A pump device 213 is disposed downstream of the air filter 212 to generate and drive the HIA through the evaporator 210. The humidity sensor 214 is disposed in the air inlet path 211 to sense the inlet humidity Hhi of the HIA. The air outlet 21B opens into an air outlet path 215 extending from the evaporator 210. The humidity sensor 216 is disposed in the air outlet path 215 to sense the outlet humidity Hho of the HOA. The tap water inlet 21C opens into a water inlet path 217 extending to the evaporator 210. The flow controller 218 is disposed in the water inlet path 217 to control the flow of TW to the evaporator 210. The flow controller 218 may comprise, for example, a valve and / or a pump device. The local control unit 219 is configured to generate control signals for the pump device 213, the flow controller 218, and the evaporator 210 based on sensor data ("measurement signals") from the humidity sensors 214, 216 to achieve the set point data SP1. For example, the setpoint data SP1 may include a target value for the outlet humidity Hho and / or a target value for the flow rate of the HOA.The local controller 219 may be implemented as, for example, a P, PI, or PID controller.

[0068] FIG. 1F is a block diagram of an exemplary dehumidifier DHU 22. The water extractor 220 is configured to receive and process the incoming air flow DIA to change at least a portion of the moisture contained therein from a gaseous state to a liquid state. This extracts EW from the DIA to generate an outgoing air flow DOA with reduced humidity. In some embodiments, the water extractor 210 is configured to extract EW by direct condensation of moisture in the incoming air flow, optionally at high pressure, by cooling the air below its dew point. For example, the water extractor 210 can include a conventional evaporator coil configured to cool the DIA and condense water. In these embodiments, the box 220A represents the evaporator coil. This type of water extraction is primarily effective when the incoming air has a high relative humidity, such as above about 40%. In general, the quality of EW obtained by this technique depends on the quality of the incoming air.

[0069] In some embodiments, the water extraction unit 210 is instead configured to extract the EW by the use of a desiccant. In these embodiments, the box 220A represents a desiccant. A desiccant is a hygroscopic material arranged to interact with the DIA. During this interaction, the desiccant adsorbs and / or adsorbs water molecules present in the DIA. The water extraction unit 220 is configured to treat the desiccant 220A to release water molecules, for example, by one or more of heating, water vapor pressure change, or UV irradiation. The released water molecules are then collected to form the EW. This type of water extraction is also effective when the incoming air has a low relative humidity, such as up to 20% or even lower. In general, the quality of the EW obtained by this technique depends on the desiccant, and in particular its selectivity for water.

[0070] The DHU 22 of FIG. 1F comprises an air inlet 22A, an air outlet 22B and a water outlet 22C. The air inlet 22A opens into an air inlet path 221 that extends to the water extraction section 220. An air filter 222 is disposed in the air inlet path 221 to remove particulate matter such as debris, dust, and possibly volatile organic components, carbon, sub-micrometer particles, etc. A pump device 223 is disposed downstream of the air filter 222 to generate and drive the DIA through the water extraction section 220. A humidity sensor 224 is disposed in the air inlet path 221 to sense the inlet humidity Hdi of the DIA. The air outlet 22B opens into an air outlet path 225 that extends from the water extraction section 220. A humidity sensor 226 is disposed in the air outlet path 225 to sense the outlet humidity Hdo of the DOA. The water outlet 22C opens into a water outlet path 227 that extends to the water extraction unit 220. A flow controller 228 is disposed in the water outlet path 227 to control the flow of EW from the water extraction unit 220. The flow controller 228 may comprise, for example, a valve and / or a pump device. The local control unit 229 is configured to generate control signals for the pump device 223, the flow controller 228, and the water extraction unit 220 based on sensor data ("measurement signals") from the humidity sensors 224, 226 to achieve the set point data SP2. For example, the set point data SP2 may include a target value for the outlet humidity Hdo and / or a target value for the flow rate of EW ("EW production rate"). The target value for the EW production rate may be set to ensure that a sufficient amount of EW is extracted over a predetermined period of time, for example 24 hours. The local control unit 229 may, for example, control the flow rate of DIA based on the inlet humidity Hdi to achieve the target value of the EW production rate. Alternatively or additionally, the local controller 229 can control the flow rate of the DIA based on the inlet humidity Hdi to achieve a target value for the outlet humidity Hdo.

[0071] Table 1 below shows the required airflow for a given Hdi to extract 11.1 ml / min EW, resulting in 16 liters per 24 hours, which corresponds to a typical daily consumption in PD therapy. Table 1 also shows the resulting Hdo. As can be seen in Table 1, the required airflow can be high when Hdi is low and / or when Hdo is relatively high. Thus, in some situations, DHU22 may not be able to achieve the target value(s). These situations are mitigated by the provision of HU21 and by joint control of HU21 and DHU22. For example, HU21 may be operated to increase Hdi by increasing Hho.

[0072] [Table 1]

[0073] Returning to FIG. 1C, it is understood that the combination of HU21 and DHU22 results in gaseous transfer of tap water TW from HU21 to DHU22 when HU21 and DHU22 are arranged such that at least a portion of the HOA from HU21 (FIG. 1E) to DHU22 is included in the DIA. This can be achieved by defining a physical path between the air outlet 21B of HU21 and the air inlet 22A of DHU22. Alternatively, it can be achieved by arranging HU21 to emit its outflow air flow HOA to the outside air at the location of HU21, and arranging DHU22 to receive DIA from the outside air at the location of DHU22, provided that air can flow from HU21 to DHU22. Gaseous transfer of water provides various technical advantages.

[0074] Gas transfer allows the DHU 22 to increase its EW production even if the amount of available air is limited, for example when the DHU 22 is located indoors and operates only on indoor air. In the following, the confined space in which the HU 21 and DHU 22 are located is generally referred to as the "premises" and may be in a patient's home or a clinic. The water vapor content of normal indoor air is typically about 1 m of air at 20-25°C and 30-70% relative humidity (RH). 3 Even if the DHU 22 is located in an enclosure with high air exchange, e.g., via a ventilation system, it may be difficult to provide the volume of air required for EW generation if the enclosure is limited in size. 2 In the apartment complex, 2400m 3 A turnover frequency of about 12 per day is required to provide a total air volume of 16 kg of liquid water. Table 2 below shows the volume of air required to extract 16 kg of liquid water for a given air humidity at the beginning of the extraction process (RH start). Table 2 also shows the final air humidity after the extraction process (RH end). As can be seen in Table 2, even with a turnover frequency of around 12 per day, the humidity of the indoor air may be undesirably low to meet the required air volume. And, if possible, the RH end is likely to be even lower near the DHU 22. A dry indoor climate may be perceived as uncomfortable or may even cause or aggravate respiratory diseases, and may also cause sore throat, eye irritation, dehydration, dry skin, etc. In general, it may be desirable for the relative humidity in the premises to be in the range of 30-70% or 40-60% for health and comfort.

[0075] It should also be noted that EC hemotherapy generally requires a much larger volume of dialysate. The required volume of air processed by the DHU 22 for extraction of EW is correspondingly larger.

[0076] [Table 2]

[0077] The HUs 21 and DHUs 22 may be arranged in a variety of configurations to perform the gas transfer of tap water. Examples of such configurations are described further below. Typically, all configurations are operable to maintain acceptable humidity within the premises of the HUs 21 and DHUs 22.

[0078] Additional technical advantages may also be achieved by appropriate design of the DHU 22. When the DHU 22 is configured to extract the EW from the desiccant, it is possible to achieve inherent purification of the EW by using a desiccant with high selectivity for water. High selectivity means that the desiccant is tailored to adsorb and / or absorb water molecules rather than other molecules that may be present in the DIA. The inherent purification by the DHU 22 may reduce or even eliminate the need to treat the extracted water by conventional water purification to ensure that the TF meets regulatory requirements or standards, e.g., water for dialysis according to ISO 23500-3. Conventional water purification typically involves reverse osmosis (RO), which is extremely expensive.

[0079] In some embodiments, the water extraction section 220 is configured to produce an EW having a conductivity of less than 10 μS / cm, preferably less than 5 μS / cm or 1 μS / cm. As will be appreciated from above, this can be accomplished by using a desiccant that has a high selectivity for water.

[0080] In some embodiments, the desiccant is an ionic or covalent porous solid, including but not limited to metal-organic and organic porous framework materials, zeolites, organic ionic solids, inorganic ionic solids, organic molecular solids, or inorganic molecular solids, or any combination thereof. The desiccant can be used in a pure single-phase formulation, as a composition of different active chemicals, and / or in combination with performance-enhancing additives that adjust its properties. The performance-enhancing additives can include data with high thermal conductivity and molar water absorption. The active compound can be used in the form of a powder, extrudate, compact, pressed pellet, pure or composite film, or sintered body. In some embodiments, the water capture material includes an active compound, such as a metal-organic framework (MOF). MOFs are porous materials with repeating secondary structure units (SBUs) linked to organic ligands. In some variations, the SBUs may include one or more metals or metal-containing complexes. In other variations, the organic ligands have acid and / or amine functional groups. In certain variations, the organic ligands have carboxylic acid groups. Any MOF capable of adsorbing and desorbing water can be used in the systems provided herein. In some embodiments, MOF-303 is used as a desiccant. MOF-303 has the structure Al(OH)(HPDC), where HPDC stands for 1H-pyrazole-3,5-dicarboxylate. Other possible MOFs for use as desiccants include, for example, MOF-801, MOF-841, and MIL-160. Combinations of MOFs can also be used as desiccants. Further examples and implementation details can be found in the articles "Metal-Organic Frameworks for Water Harvesting from Air" by Kalmutzki et al. (published in Adv. Mater. 2018, 30, 1704304) and "Practical Water Generation from Desert Air" by Fathieh et al. (published in Sci. Adv. 2018, Vol. 8, Issue 6), which are incorporated herein by reference.

[0081] FIG. 2A shows an example of a “disconnected” embodiment in which the HU 21 and the DHU 22 are physically separated and in fluid communication via the outside air. The wavy arrows reach the DHU 22 and represent the percentage of the HOA (FIG. 1E) that is included in the DIA (FIG. 1F). The disconnected embodiment facilitates installation. Separating the HU 21 from the DHU 22 provides the freedom to place the HU 21 near a water supply, for example in a bathroom or kitchen. This makes it easier to supply the HU 21 with tap water, whether this is accomplished by fluidly connecting the HU 21 to a water supply or by manually filling a tank associated with the HU 21 with water.

[0082] The non-connected embodiment relies on water vapor transfer between the HU 21 and the DHU 22, which means that moist air produced in the HU 21 is transferred to the DHU 22 by convection (natural and / or forced) and / or mixing. This "wireless water transfer" between the HU 21 and the DHU 22 through the premises can be more or less effective depending on the transfer bandwidth (or conversely, the flow resistance) between the HU 21 and the DHU 22. The transfer bandwidth depends for example on the distance between the HU 21 and the DHU 22, the ventilation characteristics of the premises, and the presence of obstacles or obstructions such as doors, furniture, etc.

[0083] An example of a different installation is shown in FIG. 2B, which is a top view of a premises including a bathroom 41, with a sink 42 and a toilet 43, separated by a door 44 from a bedroom 45 with a bed 46. The dialysis therapy is preferably performed while the patient is lying on the bed 46. The treatment system 10' is therefore placed at the bedside. As described above in relation to FIG. 1C, the treatment system 10' also includes an FGU 24 for generating TF. The DHU 22 is fluidly connected to the treatment system 10' and supplies the EW to the FGU 24. The DHU 22 may be placed close to the treatment point to avoid extensive tubing for the transport of the EW.

[0084] In a first installation example, the HU 21 is placed in the bathroom 41 in fluid connection with a permanent water supply source at the sink 21. As long as the door 44 between the bathroom 41 and the bedroom 45 is open, the moisture generated by the HU 21 will propagate over time to the DHU 22, driven for example by forced convection. The forced convection can be caused by a pumping device 213 in the HU 21, a pumping device 223 in the DHU 22, or a separate fan, ventilation system, etc. In a second installation example, the HU 21 is placed in the lower left corner of the bedroom 45 and out of the way. The HU 21 can receive tap water from the tank 30 as shown, or through a pipe connected to the water supply in the bathroom 41. When the tank 30 is used, it can be advantageous for the DHU 22 to be configured to extract more water from the ambient air than is added by the HU 21. This reduces the need for tap water, and thereby the need for the user to carry tap water from the bathroom 41 to the bedroom 42. In a third installation example, the HU 21 is placed near the DHU 22. As with the second installation, the HU 21 may receive mains water from a tank 30 as shown, or through a pipe connected to a water supply in the bathroom 41.

[0085] In some embodiments, the disconnected embodiment shown in FIG. 2A is operable to control the relative humidity in the ambient air of the premises. In the illustrated example, the controller 25 is configured to receive sensor data from one or more humidity sensors and provide target values ​​for the outlet humidity Hho of the HU 21 (FIG. 1E) and the outlet humidity Hdo of the DHU 22 (FIG. 1F) to the respective local controls 219, 229 to operate the HU 21 and the DHU 22 to achieve the target values. The target values ​​may be provided as part of the set point data SP1, SP2 of FIG. 2A. The sensor data may include one or more of the inlet humidity Hhi from the sensor 214 in the HU 21, the inlet humidity Hdi from the sensor 224 in the DHU 22, or the ambient humidity Ha from a separate humidity sensor 26 located anywhere in the premises. The sensor 26 is disclosed only for the embodiment of FIG. 2A, but may be present and used in any other embodiment disclosed herein.

[0086] The sensor data may be transmitted wired or wirelessly to the controller 25. Similarly, the setpoint data SP1, SP2 may be transmitted wired or wirelessly to the HU 21 and DHU 22. The controller 25 may be a separate device as shown, or may include one of the local controls 219, 229. Thus, in general, the functions of the local controls 219, 229 and the controller 25 may be performed by a controller, which may be centralized or distributed in any manner.

[0087] FIG. 3 is a flow chart of an exemplary method 300 of installing and operating a disconnected embodiment as described with reference to FIGS. 2A-2B. In step 301, the DHU 22 is installed at a desired location in the premises, for example near the FGU 24. In step 302, the DHU 22 is connected to a power source. In step 303, a fluid path for the EW is established between the DHU 22 and the FGU 24, or the treatment system 10′ if the FGU 24 is incorporated therein (FIG. 1C). For example, a tube may be connected to extend between a water outlet 22C on the DHU 22 and a water inlet on the FGA 24 or the treatment system 10′. In step 304, the HU 21 is installed at a desired location in the premises, for example according to any of the installation examples of FIG. 2B. In step 305, the HU 21 is connected to a power source. In step 306, tap water is provided to the HU 21. For example, HU 21 may be connected to a permanent water supply (step 306A), or tap water may be filled into a tank associated with HU 21 (step 306B). In step 307, a user may input one or more target values ​​for the premises humidity ("humidity setpoint") into the controller via an interface device (not shown), such as a keypad, keyboard, touch screen, control buttons, etc. Alternatively, the humidity setpoint may be set automatically by the controller based, for example, on the premises' natural humidity (when HU 21 and DHU 22 are shut down), or a humidity determined (by the controller) to provide favorable operating conditions, for example, to achieve a net water intake to minimize tap water demand.

[0088] In step 308, the control device performs a step response test. The step response test is performed for the purpose of configuring the control device for the premises. For example, the step response test can serve to improve the ability of the control device to maintain a proper humidity in the premises and / or to ensure that a sufficient amount of water vapor is received by the DHU 22. Step 308 may be performed automatically each time the HU 21 and / or the DHU 22 are started, or at predetermined time intervals, or when an error condition is detected by the control device, for example based on the measured humidity. For example, step 308 may be performed when the measured humidity changes in an unexpected way. Alternatively or additionally, step 308 may be performed on command by a user, for example by the user pressing a dedicated button on the HU 21 or the DHU 22. Alternatively or additionally, step 308 may be performed automatically to validate input data entered by the user, for example regarding the type or size of the premises.

[0089] In a step response test, the controller makes a step change in the operating performance of the HU 21, e.g., in terms of the amount of water vapor produced by the HU 21, and / or the performance of the DHU 22, e.g., in terms of the amount of water vapor consumed by the DHU 22. In a non-limiting example, the HU 21 can be operated to increase / decrease the flow rate of the HOA and / or to increase / decrease the humidity of the HOA. In another non-limiting example, the DHU 22 can be operated to increase / decrease the amount of EW extracted. In general, the step change can be generated by changing the operating point of the HU 21 and / or the DHU 22 or by starting / stopping the HU 21 and / or the DHU 22. After the step change, the controller monitors the sensor data representative of the humidity of the premises over time. For example, the sensor data can represent one or more of Hdi, Hhi, Ha (FIG. 2A). The time response in the sensor data represents the above-mentioned transport bandwidth of the premises. In step 309, the controller determines appropriate control parameter values ​​for joint control of HU 21 and DHU 22 based on the time response in the sensor data, e.g., from a look-up table or by evaluation of one or more predefined functions according to well-known control theory. Depending on the type of controller implemented by the controller, the control parameters may relate to one or more of a gain (P), integral (I), or derivative (D).

[0090] In step 310, the user may input further control data to the controller, including a setpoint (target value) for EW production by the DHU 22 and, optionally, a total amount of EW ("total EW") to be extracted by the DHU 22 during a given operating period. Alternatively, the control data may be retrieved by the controller from a memory within the dialysis system, e.g., the treatment system 10, the FGU 24, the HU 21, or the DHU 22. In step 311, the controller operates the HU 21 using the control parameter values ​​from step 309 to achieve the humidity setpoint (entered in step 307). In step 312, the controller operates the DHU 22 using the control parameter values ​​from step 309 to achieve the humidity setpoint and / or achieve the EW production setpoint (entered in step 310). Note that the HU 21 and DHU 22 may be jointly operated toward multiple humidity setpoints provided by different humidity sensors. It is also contemplated that HU 21 and DHU 22 may be operated separately toward different humidity set points provided by different humidity sensors. It should also be understood that for a period of time after start-up of HU 12 and DHU 22, humidity will be unevenly distributed between HU 21 and DHU 22 until a steady state condition is reached.

[0091] In step 313, the HU 21 and the DHU 22 are stopped when the accumulated amount of EW exceeds a threshold, which may be the total EW amount entered in step 310 or a predefined value. The accumulated amount of EW may be determined in any suitable manner, for example by flow measurement, volume measurement, etc., by the flow controller 228 (FIG. 1F) or a separate device. Alternatively, the accumulated amount may be given by measuring the fluid level in a tank for the collection of EW (see reservoir 23 in FIG. 1C) or by measuring the weight of such a tank. A sensor for such measurement is represented diagrammatically as 23″ in FIG. 1C. As indicated by the arrows, the method 300 may then return to perform step 310 when the HU 21 and the DHU 22 are restarted, for example according to a predefined schedule or by user command. Alternatively, as described above, the method 300 may return to step 308 and perform a step response test when the HU 21 and the DHU 22 are restarted.

[0092] At least one of the HU 21 and the DHU 22 may comprise a positioning device configured to generate position data indicative of the relative positions of the HU 21 and the DHU 22. The relative positions may complement or replace the step response test (step 308) and may be used to estimate the transport bandwidth between the HU 21 and the DHU 22 and / or to determine the control parameters (step 309). In one example, the positioning device is configured to measure the distance between the HU 21 and the DHU 22 by any conceivable technique. If data is exchanged between the HU 21 and the DHU 22 wirelessly, the distance may be estimated based on the signal strength. In another example, more advanced positioning is used, for example by connecting the HU 21 and the DHU 22 to an indoor positioning system. In a further alternative, the user may input the distance via an interface device for use by the control device.

[0093] 5A-5C show various examples of "connected" embodiments, in which at least one fluid connection device FCD 21', 21'' is arranged to extend between the HU 21 and the DHU 22. The FCD 21', 21'' defines at least one fluid path. The FCD 21' is arranged to fluidly connect the air outlet 21B of the HU 21 with the air inlet 22A of the DHU 22, thereby including at least a portion of the outflow air flow from the HU 21 in the inflow air flow to the DHU 22. In the example of FIG. 5B-5C, an additional FCD 21'' is arranged to fluidly connect the air outlet 22B of the DHU 22 with the air inlet 21A of the HU 21, thereby recirculating at least a portion of the DOA for inclusion in the HIA. One general advantage of connected embodiments over non-connected embodiments is more efficient and direct control of humidity in the DIA by eliminating the effect of the transport bandwidth of the premises.

[0094] FIG. 4 shows an example of an installation of the connection embodiment in the premises of FIG. 2B. The DHU 22 is located near the treatment system 10′ located at the bedside. The HU 21 is fluidly connected to the DHU 22 by the FCD 21′ (and optionally the FCD 21″) and is located near the DHU 22 to reduce the extent of the FCD 21′. Although not shown in FIG. 4, it is contemplated that the HU 21 and the DHU 22 are combined into a single integrated structure. The integrated structure can be space efficient and easy to install, handle, and control. The HU 21 can receive tap water from a tank 30 as shown or through a pipe connected to a water supply in the bathroom 41. In other installations (not shown), the HU 21 can be spaced apart from the DHU 22, for example as shown in FIG. 2B, with the FCD 21′ (and optionally the FCD 21) extending between the HU 21 and the DHU 22.

[0095] Except for FCD 21', the example of FIG. 5A is similar to the unconnected embodiment of FIG. 2A and may be similarly constructed and operated. In HU 21, TW is received at water inlet 21C, HIA is received at air inlet 21A, and outflow air flow HOA1 is discharged at air outlet 21B connected to FCD 21'. As shown in FIG. 5A, HU 21 may define another air outlet 21B', which discharges another outflow air flow HOA2 to the periphery of HU 21. Air flows HOA1 and HOA2 may be diverted from a common outflow air flow (see HOA in FIG. 1E) or may be two independently generated air flows. Air outlets 21B' and HOA2 are optional. In DHU 22, DIA is substantially identical to HOA1 and is received from FCD 21' at air inlet 22A. DOA is discharged at air outlet 22B, and EW is provided at water outlet 22C. Controller 25 is configured to control the combination of HU 21 and DHU 22. Controller 25 may be configured to correspond to controller 25 of Figure 2A. As noted above, the functionality of local controls 219, 229 (Figures 1E-1F) and controller 25 in general may be incorporated into a controller, which may be centralized or distributed in any manner.

[0096] The provision of HOA2 can improve the ability of the controller to control the relative humidity in the ambient air of the premises. The controller can control the exit humidity Hdo of DOA and / or the exit humidity of HOA2 to achieve the target humidity of the premises, as provided by Hdi from sensor 224 (FIG. 1F) or Ha from a separate humidity sensor (see 26 in FIG. 2A). It will be appreciated that if HOA1 and HOA2 are generated independently by HU 21, the controller can operate on a separate humidity value of HOA2, provided by an additional humidity sensor (not shown). Otherwise, the exit humidity Hho from sensor 216 (FIG. 1E) represents both HOA1 and HOA2.

[0097] The example of FIG. 5B is an "open recirculation system", where the FCD 21 is installed to recirculate a portion of the DOA. The FCD 21 is a structural recirculation device that defines at least one fluid path for the recirculated air RA. The FCD 21" extends from junction 27A downstream of the water extraction section (220 in FIG. 1F) to junction 27B upstream of the evaporation section (210 in FIG. 1E). Junctions 27A, 27B can be located outside (as shown) or inside the HU 21, DHU 22. The remainder of the DOA, designated DOA', is discharged to the environment of the DHU 22. The RA is directed by the FCD 21" to the air inlet 21A and forms part of the HIA, which also includes the incoming air flow HIA' from the environment of the HU 21. In an open recirculation system, a portion of the air treated by the HU 21 and the DHU 22 is continuously exchanged. Thereby, similar to the configurations of Figures 2A and 5A, the open recirculation system may be operated to extract a net amount of water vapor from the ambient air to reduce TW consumption. The open recirculation system may also be operated, like the system of Figure 5A, by controlling the outlet humidity Hdo of the DOA and / or the outlet humidity of HOA2 to achieve a humidity set point for the ambient air of the premises to control the relative humidity of the ambient air of the premises. However, if the humidity of the premises is provided by Hhi, the sensor 214 (Figure 1E) may be moved or supplemented by an additional sensor to measure the humidity of HIA' rather than HIA. If HU21 and DHU22 are combined in a monolithic structure, it is conceivable that DOA' and HOA2 are mixed and the humidity of the resulting mixture is measured by a dedicated humidity sensor as an alternative or supplement to measuring the humidity of DOA and HOA2 separately.

[0098] As shown in FIG. 5B, a flow controller 28 can be located in the FCD 21″ to set the percentage of DOA diverted to the FCD 21″, hereafter referred to as “recirculation percentage”. The flow controller 28 can be a valve, a pump device, etc., whereby the amount of RA is adjustable, for example, by a control signal from a controller. The recirculation percentage determines the degree of air exchange with the environment and can be set by the user or by the controller, for example, based on sensor data, based on step response tests, or any combination thereof. The DHU 22 may require a certain combination of air flow and humidity from the HU 21 to be able to reach the EW generation target. The controller can then operate the HU 21 accordingly.

[0099] 3 is equally applicable to the connection embodiments shown in Figures 5A-5B, although some steps may be modified to account for differences in construction, as outlined above. Additionally, with respect to the open recirculation system of Figure 5B, method 300 may include determining the percentage of the DOA that is recirculated and operating the system to achieve this percentage.

[0100] The system of Figure 5B has potential advantages over the system of Figure 5A: recirculation reduces airflow to and from the surroundings, which can result in quieter operation, and the system of Figure 5B may be easier to control because it is less dependent on the characteristics of the surroundings.

[0101] The example in Fig. 5C is a "closed recirculation system", where FCD 21 is installed to recirculate air through HU 21 and DHU 22 without air exchange with the surroundings. Specifically, FCD 21 connects air outlet 22B with air inlet 21A, and DOA forms HIA. Thus, air is used as the internal medium for water vapor transport from HU 21 to DHU 22. This also means that the consumption of TW in HU 21 is substantially equal to the production of EW in DHU 22.

[0102] FIG. 6 is a flow chart of an exemplary method 600 for installing and operating the closed recirculation system shown in FIG. 5C. Manual installation steps 301-306 may be the same as method 300 (FIG. 3). However, compared to method 300, steps 307-309 are omitted. After manual installation, method 600 includes step 310, which may be the same as method 300. Thus, in step 310, a user may input further control data into the controller, including a setpoint for EW production by the DHU 22, and optionally, a total amount of EW to be extracted by the DHU 22 during a given period of operation. Alternatively, the control data may be retrieved by the controller from a memory in the dialysis system, e.g., the treatment system 10, the FGU 24, the HU 21, or the DHU 22. In steps 311′-312′, the HU 21 is operated to achieve a required amount of water vapor at the inlet 22A of the DHU 22, and the DHU 22 is operated to meet the setpoint for EW production. The amount of water vapor at the inlet 22A is determined by a combination of the flow rate and humidity of the HOA. The controller can determine a combination of flow rate and humidity from the HU 21 that allows the DHU 22 to reach a set point of EW production and operate the HU 21 accordingly. For example, the appropriate operating points of the HU 21 and the DHU 22 may be determined based on data corresponding to Table 1 (above). For example, according to Table 1, if the HU 21 is operated to generate a HOA with a humidity of 70% and the DHU 22 is operated to generate a DOA with a humidity of 20%, the required air flow rate of the HOA is 16 liters / second when the temperature is 25° C. and the total EW amount is 16 liters per 24 hours. Similar to method 300, method 600 includes step 313 of shutting down the HU 21 and the DHU 22 when the accumulated amount of EW exceeds a threshold. Method 600 can then return to performing step 310 when the HU 21 and the DHU 22 are restarted.

[0103] Compared to other variations, a closed recirculation system maximizes the humidity differential across the HUs 21 and DHUs 22, thereby minimizing the airflow through them, which also allows for a compact system.

[0104] Another potential advantage of a closed recirculating system that repeatedly humidifies and dehumidifies the same air is that volatile contaminants initially present in the air are removed early in the process if the water extraction section 220 (FIG. 1F) is unable to purify the extracted water EW. Such a water extraction section 220 can be based on direct condensation. The volatile contaminants are contained in the initial portion of the EW. By operating the system to discard the initial portion of the EW, the effect of air impurities can be mitigated or even eliminated.

[0105] 5C does not require air to be circulated through HU 21 and DHU 22. For example, air can be replaced with any gas that is believed to improve the performance and / or durability of the system.

[0106] In some embodiments, the system is configured to be switched manually or by a controller between operational modes corresponding to two or more of the configurations of Figures 5A, 5B, and 5C. An example of such a system is shown in Figure 5D. An FCD 21" is arranged to fluidly connect an outlet line 122 and an inlet line 121 of the system. In the illustrated example, the outlet line 122 extends from an air outlet 22B on the DHU 22 to the ambient, and the inlet line 121 extends from the ambient to an air inlet 21A on the HU 21. The FCD 21" is fluidly connected to the outlet line 122 at outlet junction 27A and to the inlet line 121 at inlet junction 27B. In the illustrated example, a respective three-way valve 29A, 29B is arranged at each of the junctions 27A, 27B. It can be seen that the valves 29A, 29B form a flow controller operable to selectively switch the system between operational modes. In Figure 5D, the flow controllers 29A, 29B can include the functionality of the flow controller 28 of Figure 5B. Valve 29B at inlet junction 27B is optional, but may be included to better control the inflow of ambient air into HU 21. Note that the system can operate in all modes even if valve 29B is omitted. Providing valve 29B can reduce noise in the closed mode.

[0107] The flow controllers 29A, 29B are operable to control the flow rate of the RA through the FCD 21″, and therefore the recirculation rate. The flow controllers 29A, 29B may include any number of any type of valves, one or more pumps, one or more flow restrictors, etc.

[0108] The system of FIG. 5D can operate in an open mode without recirculation (see FIG. 5A), an open mode with recirculation (see FIG. 5B), or a closed mode with recirculation (see FIG. 5C). The selection of the operating mode may be based on the size of the premises, the air humidity in the premises, or user preference. The operating mode can be changed during operation of the system. In a preferred embodiment, the selection of the operating mode is performed by the controller by generating control signals for the flow controllers 29A, 29B.

[0109] The flow controllers 29A, 29B may be operated to set the recirculation percentage to any value between 0% (open mode without recirculation) and 100% (closed mode). In some embodiments, the recirculation percentage may be set to one or more predefined values ​​between 0% and 100% to operate the system in an open mode with recirculation. Alternatively, the recirculation percentage may be continuously varied between 0% and 100%, or in any other range, by the valve devices 29A, 29B. In some embodiments, the system is switched between a closed mode and one of the open modes, e.g., an open mode without recirculation. This corresponds to switching the flow controllers 29A; 29B between a recirculation percentage of 0% and a recirculation percentage of 100%.

[0110] The closed mode may be selected to minimize the required air flow rate and / or to avoid affecting the ambient air in the premises, while the open mode allows air exchange with the environment and offers the opportunity to reduce tap water demand by extracting some of the water from the environment rather than from evaporated tap water. Additionally, the open mode allows control of the air humidity in the premises.

[0111] Another reason for switching between operating modes is to reduce noise in the system: closed mode is likely to be quieter than open mode and can therefore be used at night, while open mode can be used during the day, for example to extract water from the environment.

[0112] Although not shown in FIG. 5D, the system may be operable in a pure DHU mode in which the HU 21 is disabled. In the pure DHU mode, the system may be configured to pass ambient air through the disabled HU 21 to the inlet 22A of the DHU 22. Alternatively, the DIA may be admitted to the DHU 22 via an air inlet valve (not shown) on the FCD 21' or the DHU 22. The controller may set the system in the pure DHU mode when it is found that the ambient air and the premises support sufficient water extraction. For example, the pure DHU mode may be used in premises with a climate having a high moisture content, especially when the premises receive outdoor air, for example, through open doors or windows. In another example, the pure DHU mode may be used in premises with a high air exchange, for example, through an air conditioning system. The controller may detect any such premises by a step response test, based on information entered by the user, or by a combination thereof.

[0113] It is contemplated that the HU 21 and the DHU 22 are configured as modules that may be structurally combined to form an unconnected embodiment or any type of connected embodiment. Such a modular system may include a connection sensor configured to sense a fluid connection status between the HU 21 and the DHU 22. The controller may respond to the fluid connection status indicated by the connection sensor and modify the operation of the controller accordingly. The controller may select different operating parameters and / or selectively include or exclude operating steps depending on the fluid connection status. Some non-limiting examples of the use of the connection sensor are shown in Figures 7A-7D. In Figure 7A, the HU 21 and the DHU 22 are spaced apart in an unconnected embodiment, and the connection sensor 27 indicates a spaced apart state. In Figure 7B, the HU 21 and the DHU 22 are interengaged to define a trapped fluid path for the flow of humid air (HOA), and the connection sensor 27 indicates an open state without recirculation. In Figure 7C, the HU 21 and the DHU 22 are connected by a tube 21', and the connection sensor 27 indicates an open state without recirculation. In FIG. 7D, the HU 21 and DHU 22 are connected by both tube 21′ and recirculation tube 21″, and the connection sensor 27 indicates an open state with recirculation. In the example shown, the connection sensor 27 is activated automatically depending on how the HU 21 and DHU 22 are connected. The connection device 27 in each of FIGS. 7A-7D may be of any type, for example, a mechanical switch, a magnetic sensor, a capacitive sensor, etc. In a variant, the connection device 27 is manually activated by a user to indicate the fluid connection state to the control device.

[0114] In a variant of the disconnected embodiment (FIG. 2A), the DHU 22 is equipped with an auxiliary humidifier, which can be operated to supplement the HU 21 when the transfer bandwidth is insufficient, for example as a result of a large distance between the HU 21 and the DHU 22, poor ventilation in the premises, or a temporary blockage of the passage from the HU 21 to the DHU 22. The need to operate the auxiliary humidifier can be set by the user or inferred by the control device based on a step response test and / or distance (if known). For example, the user may prefer to place the HU 21 in a bathroom near the water supply. When the transfer bandwidth is limited, the user can fill the tank of the HU 21 with a first amount of tap water and fill the tank of the DHU 22 with a second amount of tap water. The second amount can be smaller than the first amount when the HU 21 operates as the main humidifier in the premises.

[0115] It is conceivable to connect the HU 21 to receive HIA from the outside air and / or the DHU 22 to provide DOA to the outside air. This reduces the impact of the system on the humidity in the premises. It may also reduce the required capacity of the HU 21.

[0116] Returning to the example installation of Figs. 2B and 4, it may be advantageous to provide a user with advance notice that the tank 30 needs to be refilled, and possibly provide the amount of water that needs to be added to the tank 30 for the user's convenience. Advance notice may be given via a feedback unit, e.g., a display or a speaker, connected to the control device. In one embodiment, as shown in Figs. 2B and 4, the tank 30 comprises a level sensor 31 that generates a signal indicative of the current fill level of the tank 30. The level sensor 31 may be of any conventional type, e.g., ultrasonic, capacitive, optical, magnetostrictive, magnetoresistive, etc. Alternatively, the level sensor 31 may measure the weight of the tank 30. The control device may determine the TW consumption based on the signal from the level sensor 31 and estimate by prediction or extrapolation the time when the tank 30 will be empty. The control device may then inform the user of the need to refill the tank 30, and possibly the amount of water to be added to the tank, well before this time. In another embodiment, the control device is configured to estimate the TW consumption based on sensor data of humidity in the premises. The sensor data may include one or more of the inlet humidity Hhi (sensor 214 in FIG. 1E), the inlet humidity Hdi (224 in FIG. 1F), or the ambient humidity Ha (sensor 26 in FIG. 2A). The TW consumption can be estimated by using a computational model of the system connected to the treatment system 10, 10'. The computational model may be based on an analytical function or may be a model based on machine learning. The computational model is configured to take into account the water consumption by the treatment system through the use of the treatment fluid. The consumption of the treatment fluid may be given by a treatment prescription or may be measured. The computational model is configured to estimate the water production EW of the system from the ambient air. The EW production depends on the known system settings and the humidity of the ambient air versus time, given by or predicted from the sensor data. The computational model may take into account the results of one or more step response tests to predict the humidity. The TW consumption is given by the difference between the EW production and the water consumption of the treatment system. Given the computational model, the time when the tank 30 is empty can be estimated.Well in advance of this point, the controller can inform the user of the need to refill the tank 30, and potentially the amount of water that should be added to the tank.

[0117] FIG. 8 is a flow chart of a method 800 for providing a treatment fluid that may be performed by the system disclosed herein. In step 801, an incoming air flow HIA is treated to generate an outgoing air flow HOA having increased humidity compared to the incoming air flow HIA. Step 801 may be performed by the HU 21. In step 802, at least a portion of the outgoing air flow HOA is included in a further incoming air flow DIA that is treated in step 803. Step 802 may be performed by disposing the HU 21 relative to the DHU 22 with or without the use of a fluid connection device 21′. In step 803, the further incoming air flow DIA is treated for extraction of liquid water EW. Step 803 may be performed by the DHU 22. In step 804, a treatment fluid is generated by mixing at least a portion of the liquid water EW with one or more substances. Step 804 may be performed by the FGU 24.

[0118] It should be understood that the controller can operate in either relative humidity or absolute humidity. For example, the measured relative humidity can be converted to absolute humidity by also measuring the temperature.

[0119] While the subject matter of the present disclosure has been described in connection with what are presently considered to be the most practical embodiments, it is to be understood that the subject matter of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements that come within the spirit and scope of the equivalents of the appended claims.

[0120] Additionally, although acts are shown in the figures in a particular order, this should not be construed as requiring that such acts be performed in the particular order shown, or in sequential order, or that all of the shown acts be performed, to achieve desirable results.

Claims

1. 1. A system for providing a treatment fluid (TF) for dialysis therapy, the system comprising: a fluid generator (24) configured to generate said treatment fluid (TF) by mixing one or more substances (F1, ..., Fn) with water; a dehumidification section (22) configured to receive a first flow of air (DIA), process the first flow of air (DIA) to extract liquid water (EW), and provide the liquid water (EW) for the fluid generation section (24); a humidifier (21) configured to receive a second air flow (HIA) and process the second air flow (HIA) to generate a third air flow (HOA) having an increased humidity compared to the second air flow (HIA), the humidifier (21) being arranged to include at least a portion of the third air flow (HOA) in the first air flow (DIA), system.

2. the dehumidification unit (22) comprises a desiccant (220A) arranged to adsorb and / or absorb moisture from the first air flow (DIA) and treated by the dehumidification unit (22) to extract the liquid water (EW) from the desiccant (220A); The system of claim 1 .

3. The desiccant (220A) is configured to be highly selective for water. The system of claim 2.

4. The liquid water (EW) extracted from the first air flow (DIA) has a conductivity of less than 10 μS / cm, preferably less than 5 μS / cm, or less than 1 μS / cm; A system according to any one of claims 1 to 3.

5. a control device (25, 219, 229) configured to jointly operate the humidifier (21) and the dehumidifier (22) to achieve a set point defining an air humidity in a space (41, 45) comprising the humidifier (21) and the dehumidifier (22); A system according to any one of claims 1 to 4.

6. The control device (25, 219, 229) is further configured to operate the dehumidifier (22) to achieve a set point defining an amount of liquid water (EW) extracted per unit time. The system of claim 5.

7. The control device (25, 219, 229) is further configured to deactivate the humidifier unit (21) and the dehumidifier unit (22) when an accumulated amount of liquid water (EW) exceeds a threshold.

7. A system according to claim 5 or 6.

8. and further comprising at least one humidity sensor (214; 224; 26) configured to generate a measurement signal (Hhi; Hdo; Ha) representative of the air humidity in the space (41, 45). A system according to any one of claims 5 to 7.

9. the control device (25, 219, 229) is configured to perform a step response test by inducing a step change in an operational performance of at least one of the humidifier (21) or the dehumidifier (22), monitor the measurement signals (Hhi; Hdo; Ha), and determine a control parameter value for the control device (25, 219, 229) based on the measured air humidity in the space as a function of time following the step change. The system of claim 8.

10. the at least one humidity sensor is configured to measure the air humidity in at least one of the first air flow and the second air flow (DIA, HIA); The system of claim 9.

11. a connection sensor (27) configured to sense a fluid connection state between the humidifying section (21) and the dehumidifying section (22), and the control device (25, 219, 229) is operable to modify the operation of the control device in response to the fluid connection state sensed by the connection sensor (27). A system according to any one of claims 5 to 10.

12. The system further comprises at least one fluid connection device (21') between the humidifying section (21) and the dehumidifying section (22), the humidifying section (21) being configured to emit at least a portion of the third air flow (HOA) into the at least one fluid connection device (21'), and the dehumidifying section (22) being configured to receive the first air flow (DIA) from the at least one fluid connection device (21'). A system according to any one of claims 1 to 11.

13. The humidifying section (21) and the dehumidifying section (22) are combined into an integral structure. The system of claim 12.

14. The dehumidification unit (22) is configured to output a fourth air flow (DOA) that is generated when the first air flow (DIA) is treated for the extraction of the liquid water (EW), and the system further defines a fluid path (21'') configured to redirect at least a portion of the fourth air flow (DOA) to the air inlet (21A) of the humidification unit (21) and to include the at least a portion of the fourth air flow (DOA) in the first air flow (HIA).

14. A system according to claim 12 or 13.

15. the fluid path (21'') is arranged to redirect the fourth air flow (DOA) to the air inlet (21A) of the humidification section (21) so that the fourth air flow (DOA) forms the first air flow (HIA); The system of claim 14.

16. a flow controller (28; 29A, 29B) operable to set the amount of the fourth flow of air (DOA) redirected to the air inlet (21A) of the humidification section (21); The system of claim 14.

17. The system is switchable between a first operation mode and a second operation mode by operation of the flow controllers (28, 29A, 29B), the system being configured in the first operation mode to admit ambient air into the second air flow (HIA) and to supply at least a portion of the fourth air flow (DOA) to the ambient air, and in the second operation mode, the system being configured to direct the fourth air flow (DOA) to the air inlet (21A) of the humidifier (21), whereby the fourth air flow (DOA) forms the first air flow (HIA).

17. The system of claim 16.

18. The system is configured to provide all of the fourth flow of air (DOA) to the ambient air in the first mode of operation.

20. The system of claim 17.

19. an inlet line (121) connected to the air inlet (21A) of the humidifier section (21) and an outlet line (122) connected to an outlet (22B) of the dehumidifier section (22) for receiving the fourth flow of air (DOA) from the dehumidifier section (22), the fluid path (21'') being fluidly connected at a first junction (27A) on the outlet line (122) and a second junction (27B) on the inlet line (121), the flow controller (28; 29A, 29B) configured to control the air flow rate through the fluid path (21'') from the outlet line (122) to the inlet line (121), 19. A system according to any one of claims 16 to 18.

20. The humidifier (21) is configured to emit the third air flow (HOA) into ambient air, and the dehumidifier (22) is configured to receive the first air flow (DIA) from the ambient air. A system according to any one of claims 1 to 11.

21. The humidification section (21) is configured to receive tap water (TW) and to treat the tap water (TW) to generate the third air flow (HOA) from the second air flow (HIA) and the tap water (TW).

21. A system according to any one of claims 1 to 20.

22. the humidifier (21) is connected to receive the tap water (TW) from a tank (30), and the system is configured to estimate a time point of exhaustion of the tank (30) based on a signal from a level sensor of the tank (30) or based on measured air humidity in a space (41, 45) comprising the humidifier (21) and the dehumidifier (22), and to output a user command to add tap water to the tank (30) prior to said time point.

22. The system of claim 21.

23. The system is configured to estimate the time of exhaustion by using a computational model configured to predict the extraction of the liquid water (EW) as a function of air humidity and by further using data indicative of consumption of the treatment fluid (TF) by an operational treatment system connected to receive the treatment fluid (TF) from the system.

23. The system of claim 22.

24. a reservoir (23) configured to receive and accumulate the liquid water (EW) from the dehumidification unit (22) or the treatment fluid (TF) from the fluid generation unit (24); 24. A system according to any one of claims 1 to 23.

25. 1. A method of providing a treatment fluid for use in dialysis therapy, comprising the steps of: treating the first air flow for extraction of liquid water (803); generating the process fluid by mixing at least a portion of the liquid water with one or more substances (804); Treating a second air flow (801), to generate a third air flow having an increased humidity compared to the second air flow; and including (802) at least a portion of the third air flow in the first air flow. method.

26. 25. A computer implemented method for operating a system according to any one of claims 1 to 24, comprising the steps of: receiving at least one measurement signal (Hhi; Hdi; Ha) representative of air humidity in a space (41, 45) comprising said humidifier (21) and said dehumidifier (22); and operating said humidifier (21) and dehumidifier (22) jointly to achieve a predetermined air humidity in said space (41, 45) as indicated by said at least one measurement signal (Hhi; Hdi; Ha), Computer-implemented method.

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