The present invention concerns a modular three- fluids contactor with hydrophobic planar membranes and high-efficiency integrated plant for air conditioning utilising such a contactor.

More in detail, the present invention radically innovates the CMC contactor ("Combined Membranes Contactor") with capillary membranes which is the subject matter of the patent application WO 2012/042553. The new contactor is composed by modules which are easily stackable and can be produced in an industrial way. The invention concerns also an integrated plant for air conditioning utilising the improved CMC according to the invention. The plant integrates a hybrid plant operating with liquid desiccants and heat exchange batteries placed in series/parallel. The integrated plant is provided with a thermovector fluid flow switching valve in order to implement with higher energetic efficiency also the winter heating besides the conditioning in the intermediate and summer seasons .

State -of - the - art

In the important fields (industrial and civil) of the treatment of air for the dehumidification and the conditioning, besides the traditional vapour compression refrigeration cycles, plants utilising hygroscopic solutions (liquid desiccants) such as, for example, aqueous solutions of LiCl, CaC12, etc. find more and more room as well. It is indeed known since long time that the dehumidification of air can be realised also in a "chemical" way, utilising solid or liquid desiccant substances . Such a method can be advantageous because it allows the control of the specific humidity irrespective of the temperature. This entails the possibility of obtaining significant energetic savings with respect to the traditional dehumidification process, in particular in the presence of high latent loads or when one has at disposal "free" thermal energy to regenerate the desiccant substance. Such substances are mainly utilised in the industrial field for the dehumidification of air in devices providing the direct air-solution contact, both in the absorption and in the regeneration phase.

For this reason, mixed (hybrid) plants appear today to be particularly interesting for their high energetic efficiency, which utilise liquid desiccants to face the latent part of the thermal load (air dehumidification) and vapour compression refrigeration cycles to face the sensible part (air cooling) .

in such hybrid systems, the cooling machine can operate at an evaporation temperature that is higher and a condensation temperature of the thermovector fluid that is smaller of what can be obtained in the traditional plants, and this entails a clear improvement of the energetic efficiency of the refrigeration cycle (larger coefficients of performance (COP) ) . The regeneration is realised by exploiting the thermal energy transfer to the condenser of the refrigeration cycle and therefore these plants need not further thermal energy. The overall energetic saving can attain 30-40% with respect to the traditional technology, which, in order to dehumidificate air, has to necessarily cool down the latter under dew temperature, with further improvements in the case of high latent loads.

However, the utilisation of the liquid desiccants stresses phenomena of dragging of absorbent solution drop loads in the air in the plants with dehumidification contactors in direct contact (the acqueous solutions of LiCl, CaCl2 are highly corrosive with respect to almost all the metals with technical interest) .

Moreover, another objective of the international research is the reduction of the absorbed power from the desiccant solution circulation pumps . These objective is sought by reducing the solution flowrate both in the dehumidification contactor and in the regeneration contactor and by controlling temperature of the solution by means of internal thermal exchanges. The thermal exchanges are realised by constructing thermovector fluids circulation systems (cold water, air cooled by free-cooling techniques) .

Since some years in the University of Genoa, the possibility of avoiding the air-desiccant direct contact by means of the use of hydrophobic membrane contactors has been explored both experimentally and theoretically. In these components, the energy and mass exchanges between the phases occur through a membrane, avoiding the direct contact between the phases. By this technology, one can avoid the drawbacks of the direct contact such as, for example, the dragging of desiccant the droplets in the treated air, the progressive pollution of the solution by atmospheric powders, the impossibility of use on transportation means, etc. The membrane contactors allow high exchange surfaces per unit volume, limited load leaks on the air side, and can be utilised on transportation means.

A first result of this research has been a three- fluid contactor (air, desiccant liquid and thermovector fluid) with capillaries in hydrophobic membrane of separation between air and desiccant, according to what is described in the patent application WO2012/042553. The use of this contactor allows to realise compact hybrid plants which are apt also to the use on transportation means .

However, the conductor of the International patent application WO2012/042553 presents the following inconveniences :

1. The air flow within the membrane capillaries occurs in conditions of laminar motion regime, with very small mass and heat transportation coefficients on the air side.

2. One has to utilise self-supporting capillaries with small diameter (even smaller than 1 mm) , what inevitably entails high load losses for the process air and/or reduced flowrate of air;

3. The CMC is not very compact and is not modular. It is object of the present invention to provide a three-fluids contactor which solves the problems and overcomes the drawbacks of the prior art.

It is subject matter of the present invention a modular contactor device as in the enclosed claims.

It is further subject matter of the present invention and integrated air dehumidification and conditioning plant according to the enclosed claims.

It is further specific subject matter of the present invention a free cooling plant for rooms according to the enclosed relevant claims.

The invention will be now described by way of illustration but not by way of limitation, with particular reference to the drawings of the enclosed figures, wherein:

- figure la shows a rectangular frame typical of the invention, with the apertures for the refrigerant (A) , which flows inside the tubes, and for the desiccant (B) , which flows outside the tubes;

- figure lb shows a repetitive module realised by thermal welding or soldering the frame on the top and on the bottom to a membrane, according to the invention;

- figure lc shows a detail of the tubes wherein the refrigerant flows (the observation point is from inside the aperture A of figure la) ; one notes also the passage space between the tubes for the desiccant entering the aperture B;

- figure 2a shows a detail of the frame, the membrane and a spacer placed between two frames, according to the invention;

- figure 2b shows the assembly of a CMC component according to the invention constituted by 5 superposed frames and 6 spacers;

- figure 2c shows a detail of figure 2b, with the perimetral holes obtained in the frames for the insertion of the assembly tie-beams;

- figure 3a shows a detail of the end rigid plates, according to the invention, with the cylindrical joints of inlet and outlet of the refrigerant fluid and the desiccant and with the holes for the assembly tie-beams;

- figure 3b shows a final assembly in the CMC according to the invention;

- figure 4 shows a rectangular frame according to a further embodiment of the invention, wherein the thermovector fluid makes a coil path with a "U" inversion;

- figure 5 shows an angular frame according to a further embodiment of the invention, wherein the thermovector fluid that makes a coil path with two "U" inversions;

- figure 6 shows an assembly of a CMC component according to the invention which is constituted by superposed frames according to figure 5 and by a suitable number of spacers,-

- figure 7 shows the same CMC of figure 7 in a top view;

- figure 8 shows several sets of modules according to the invention and connected together to form a CMC;

- figure 9 shows a hybrid plant for the dehumidification of air with CMC1 (dehumidifier) ,

CMC2 (regenerator) and HE heat recuperator, according to the invention; in the circuit, there are the following components indicated: with L the lamination valve, with ET the solution/expansion reserve container, with C the compressor and PI and P2 are pumps;

- figure 10 shows an integrated plant according to the invention for the conditioning of air with CMC1 (dehumidifier) and CMC2 (regenerator) with two traditional thermal exchange batteries in series and in parallel (Bl and B2) ; the thermal recuperator HE is disposed between CMC1 and CMC2. VC represents the 4-ways switching valve on the 2015/000054

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circuit of the batteries.

Detailed description of embodiments of the invention

The modular CMC conductor according to the invention is obtained by superposing plane modules and spacers in an alternated way. The modules, with flat geometry, are delimited on the top and on the bottom by a membrane sheet which is thermally welded or soldered on a suitable frame. The flat spacers support the membrane sheets, allowing the process air flow. Obviously, different spacers forms can be adopted, which are also suitable to allow a better longitudinal mixing of the air.

Figure la shows an internal view of a module 100 of the CMC contactor according to the invention. One observes a rectangular frame 110, which is a basic component for the construction of the CMC contactor (but other non-rectangular frame forms are equally possible, therefore in general one will speak of a generic frame) .

Within the frame, rigid tubes 120 are disposed, which are in a material resistant to the corrosion (for example titanium) and in whose internal volume the flow of the refrigerant is provided. The tubes, with a main extension direction, are suitable to be run through by said thermovector fluid and fixed to said frame 110, 110', 110' ' in such a way that they are spaced apart and disposed on the frame plane.

Preferably, the tubes cross the frame elements 115 and by means of their internal volumes connect the apertures A with each other, which are placed at the end of the frame. In the present embodiment further frame elements 116 are provided, which are internal to the elements 115. The tubes, crossing the elements 116, leave free sections to allow, between the apertures B, the flowing of the desiccant solution.

The tubes 120 can have a cross section which is circular, rectangular or of any other geometrical form, provided that they are spaced apart to the end of allowing the flow of the desiccant solution.

Figure lb shows the repetitive module 100 of the CMC, which is realised by thermal welding or soldering / gluing on the top and on the bottom a membrane 131, 132 to the frame. A chamber is therefore created between the membranes 131, 132 and the tubes 120, wherein the desiccant solution will be able to flow between the entrance B on one side and the exit B on the other side.

In the figures, a gasket 111 can be recognised, which is suitable to guarantee the tight connection of the stacked modules .

In figure lc, a detailed view of such a module is provided with reference to the input section, along the frame element 115, of the refrigerant fluid flowing within the tubes. In such a figure, between tubes 120, the presence can be recognized, in the frame elements 116, of free openings for the inlet and outlet of the desiccant from the interspace delimited on the bottom and on the top by membrane sheets 131, 132. The membrane 131, 122 extends between the opposite elements 116 and the opposite sides of the frame 110. However, any other configuration suitable to create an inlet and an outlet of the desiccant is here encompassed.

It is also possible to insert a spacer network (not shown) between the tubes 120 and the membrane 131, 132. 4

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The alternated superposition of modules 100 and flat spacers allows to realise the CMC according to the invention.

In figure 2a, one can recognise the upper spacer 140 which is placed above the upper membrane 131 of the module 100. Between the membrane and the spacer, a room for the passage of process air is created. One notes that in the illustrated embodiment the frame 110 has different thicknesses. The part 112, external to the zone covered by the membrane 131, 132 and the spacer 140, has a larger thickness D, whilst the internal part 113, corresponding to the surface covered by membrane 131, 132 and spacer 140, has a smaller thickness d. These allows on one hand to make the desiccant flowing and pouring out in the B zones and the refrigerant in the A zones, on the other hand to create a suitable free section for the passage of process air only in the central part of module 100. One could also think about providing a spacer on the whole surface of the frame, shaping it in such a way to create separated compartments for the inlet/outlet of refrigerant, desiccant, process air.

In figure 2b, the perspective view of a CMC 1000 composed by five frames 110 and six spacers 140 is given. Suitable gaskets 111 seal the collector compartments of the refrigerant fluid (A) and the desiccant (B) . The CMC is finally delimited by two end rigid plates presenting cylindrical joints of inlet and outlet of the refrigerant fluid and the desiccant, shown in figure 3a.

Figure 2c gives the detail of the holes 117 provided in the modules for the positioning of the assembly tie-beams which are able to exert the traction 2015/000054

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needed to keep together the assembly of the CMC component and to guarantee the good functionality of all the baskets. The component is finally completed by two rigid end plates 150 , provided with holes for the tie-beams as well, and provided with inlet and outlet connections for the refrigerant fluid and the desiccant, as represented in figure 3a .

Figure 3b shows finally the view of the CMC as it appears when completed. The air enters and exits through the compartments 1500 . In the case of counter- current flow, the refrigerant enters into the inlet 1100 and exit from the outlet 1400 . The desiccant enters from the entrance 1300 and exits from the outlet 1200 .

The improvement introduced by the invention entails definite advantages in terms of compactness with respect to the previous component, improving further its energetic efficiency thanks to the possibility of utilising liquid desiccant with better thermal-physical characteristics and thanks to the reduction of the load leaks on the air side and on the solution side. It is here recalled that the solutions of LiCl combine high mass transportation potential and the relatively low viscosity.

With reference to figure 4 , a further embodiment of the present invention provides a contactor 5000 the tubes 120 are divided into two groups 120i and 120 ₂ . There is an inlet of the thermovector fluid in the part 161 of the frame, which is divided by the part 163 of the frame from which the thermovector fluid exits after having made the U-inversion in the part 162 on the opposite side of the frame at the opposite end of the tubes. In such a way, one can place inlet and outlet on the same side of the frame.

Figure 5 illustrates an embodiment of the invention which is similar to that of figure 4, wherein the contactor 4000 provides that the tubes 120 are divided into three groups 120i, 120 ₂ , 120 ₃ . The frame on a side is divided into two parts 161 of inlet and 162 of inversion, whilst on the opposite side it is divided into a part of inversion 162 and outlet 163. In such a way, the path of the thermovector fluid is tripled in the same frame.

Figures 6 to 8 illustrated the CMC component 4000 according to the invention in the case wherein the frames 110' ' are those of figure 5. The coverings 4100 and 4200 are illustrated, which limit on the top and on the bottom the frames stack constituting the CMC. The hole 4300 is for the inlet or the outlet of the desiccant fluid, whilst the hole 4400 is for the inlet or outlet of the thermovector fluid. The air enters in the direction 4500. The frames are welded or soldered with each other in groups, in such a way to reduce the use of O-ring gaskets.

The following figures (figure 9 and figure 10) illustrate two possible architectures of hybrid plants utilising CMC, according to the invention. The plant of figure 9 is particularly useful to dehumidificate air. A first contactor CMC1 according to the invention is utilised to dehumidificate air whilst a second contactor CMC2 according to the invention works as regenerator to re-concentrate the diluted solution coming from the CMC1 (and therefore more in general CMC2 is a regeneration unit) . The thermal and mass exchanges in the two contactors are opposed one to the other: in the CMC2 , the water absorbed in the CMC1 is discharged in the external air. This mass transportation between CMCl and CMC2 is realised by a solution exchange between the two components, which is obtained with the pumps PI and P2. In the circuit connecting CMCl and CMC2 , a heat exchanger

(recuperator) HE is inserted. As represented in figure 9, two pumps PI and P2 feeding HE move the desiccant solution in this circuit. The recuperator HE, in a material resistant to corrosion (plastic/resistant metal) , reduces the amount of parasitic thermal energy that transfers from CMC2 to CMCl operating a thermal exchange between the hot and more concentrated solution returning from the CMC2 and the diluted and cold solution from CMCl. C is the compressor to cool down the refrigerant fluid, L is a lamination valve, ET is an expansion tank/vessel for the desiccant solution.

It is observed that the possibility of dehumidificating air without necessarily having to cool it down can allow energetic savings above all in the intermediate seasons. In the case it is however necessary to realise, besides the air dehumidification, also a significant cooling/heating of it, it is appropriate to make reference to plant architectures with thermal exchange batteries (evaporator/condensator) placed in series/parallel to the CMC and feed it by the flow rate of the refrigerant fluid.

Figure 10 shows a realisation scheme of an integrated plant wherein the two CMCs, the dehumidificator CMCl and the regenerator CMC2 according to the invention are disposed respectively in series and in parallel to the traditional batteries Bl and B2 of thermal exchange. The evaporation/condensation temperature of the refrigerant fluid in the batteries Bl and B2 is preferably respectively the same in the CMCl and CMC2. By means of the three-ways valves VI, V2, V3 and V4 it is possible, in an embodiment, to subdivide the flow rate of the refrigerant between CMCl and Bl as well as between CMC2 and B2, up to a point wherein one can exclude completely the one or the other of the two cited components. The integrated plant of figure 10 can therefore operate as the hybrid of figure 9 and as traditional heat pump.

This architecture of integrated plant presents great interest for the conditioning of electrical vehicles. Indeed, it can operate as hybrid in the summer/intermediate seasons regime and as heat pump in the winter regime by using a four-way switching valve. One has to recall indeed that the winter heating, if realised with the direct use of electric energy, disadvantages heavily the autonomy of an electric vehicle (because in this case thermal energy from the engine is not available as in the traditional vehicles) . In the case of figure 10, one can send hot air the cabin inverting, by means of the four-ways switching valve VC, the direction of circulation of the refrigerant fluid between the only batteries, operating the three-ways valves to close partially/totally the refrigerant feed to the CMC. The switching valve VC allows to pass from the summer functioning to the winter functioning by inverting the flow of the refrigerant. The inversion can be realised automatically when requested by the climate conditions. In the case of complete exclusion of the CMC, the plant of figure 10 would function with the battery B2 operated as an evaporator and Bl as condensator and in fact as a traditional heat pump by feeding hot air in the cabin.

In the sector of the air treatments, besides the dehumidification of air and the ambient conditioning, it is here recalled that the invention can have many other applications: for example, in the sector of conservation of foodstuffs (for example refrigerated storehouses, refrigerated transportations) a possible use concerns the prearranged dehumidification of air before its inlet in the batteries to cool down air to the end of reducing/avoiding defrosting on the batteries .

The CMC component can be utilised as evaporative condenser utilising, in place of the desiccant, water to reduce, thanks to the intense latent heat exchanges with the ambient air, the condensation temperature of the refrigeration cycles, improving their energetic efficiency (larger COP values) . It is also possible, always utilising simply water, to use CMC components to realise forms of passive free cooling of confined rooms, etc. In the case of rooms free cooling plant, an evaporative free cooling unit is comprised for the production of free cooled water to feed suitable radiating panels to the end of realising internal comfort conditions in said rooms. Said free cooling unit utilises a three fluids, air, refrigerant fluid and a liquid phase contactor, the plant being characterised in that:

- the contactor is the modular contactor according to the invention;

- the liquid phase is water that cools down humidifying air running through the modular contactor; 2015/000054

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- the refrigerant fluid feeds in closed circuit said radiating panels and is constituted by water flowing within the tubes of the modular contactor. The CMC contactor subject matter of the present application presents, with respect to the capillaries contactor described in WO2012/042553 , the following advantages :

1. The airflow through suitable spacers placed between the membranes occurs in conditions of turbulent motion regime and not in the laminar motion regime any longer, with much larger mass and heat transportation coefficients on the air side.

2. Thin flat membranes (100-200 micrometers) can be used without having necessarily to use self- supporting capillaries of small diameter (even smaller than 1 mm) to which high load losses and/or reduced flow rate inevitably corresponded for the process air;

3. The new CMC, on equal performances, is much more compact and is modular: indeed it can be assembled by superposing modules and spacers up to the achieving of the exchange surface required in the various applications .

The integrated plant for the air conditioning with the CMC improved according to the invention is composed by the hybrid plant already described in WO2012/042553 , with traditional batteries of thermal exchanges placed in series/parallel and has at disposal a refrigerant flow switching valve to be able to realise with good energetic efficiency the winter heating besides the conditioning in the intermediate and summer seasons . The plant according to the invention allows indeed remarkable savings of energy both during the dehumidification and the free cooling typical of the intermediate and summer seasons and winter case, when it can operate as simple heat pump to feed hot water in the ambient. Its application to the conditioning of electric vehicles is particularly interesting to the end of obtaining relevant increasing of autonomy, on equal comfort of the passengers. Indeed, in the totally electrical driven vehicles, it is not possible to exploit the thermal energy discarded by the engine to heat up hot air to be fed in the cabin as in the traditional vehicles. The proposed plant is able to utilise, thanks to the improved the CMC with tubes in a material resistant to corrosion (for example titanium) , solutions of LiCl/CaCl ₂ as desiccants, avoiding any corrosion problem.

The technical advantages of the integrated plant according to the invention are:

- in the intermediate/summer seasons regime, above all in the humid climates, the plant allows significant energetic savings (30-40%) with respect to a traditional air conditioning plant; it allows moreover to realise in the intermediate seasons the only dehumidification of air (which is impossible with a traditional plant) .

- The application of the integrated plant according to the invention on electric vehicles allows remarkable increases of autonomy on equal comfort of the passengers.

- In the winter regime, the plant can operate also as a simple heat pump, thanks to the action of a simple switching valve to invert the circulation direction of the refrigerant fluid between the only batteries, thus excluding completely the CMCs. - The proposed plan is able to utilise, thanks to the improved CMCs, all the liquid desiccants, among which also those with better thermal- physical and thermal-dynamical properties (for example LiCl) without corrosion problems.

- Thanks to the improved CMCs, the assembly of this plant comes out to be relatively simple; all the other components can be indeed they can directly on the market.

The main application fields of the invention are:

- air conditioning in civil and industrial ambients ;

- conditioning of transportation means;

- cold chain.

Bibliography:

1. C. Isetti, E. Nannei, A. Bottino, G. Capannelli, Italian Patent Application N. RM2010A000508 "Modulo contattore con membrane capillari integrato in uno scambiatore di calore ed impianto ibrido per la deumidificazione/condizionamento dell' aria", Filing date: 30 September 2010.

2. C. Isetti, E. Nannei, B. Orlandini, A. Bottino, G. Capannelli, "Sensibile and latent heat exchangers to improve energy efficiency of AC systems " 4th European Workshop Mobile Air Conditioning and vehicle thermal systems 2011, Turin, 1-2 December 2011.

3. C. Isetti, E. Nannei, B. Orlandini , "Realizzazione di uno scambiatore evaporativo a membrana e prove sperimentali" , Condizionamento dell' aria, riscaldamento, refrigerazione CDA, 4, pp.12- 16, 2012. 4. C. Isetti, E. Nannei, B. Orlandini , "Condensatori evaporativi a membrana per una migliore efficienza energetica dei cicli frigorigeni" , Condizionamento dell 'aria, riscaldamento, refrigerazione CDA, 5, pp. 12-16, 2012.

5. C. Isetti, E. Nannei, A. Bottino, G. Capannelli, "Contactor module with hydrophobic capillary membranes, integrated in a heat exchanger and hybrid plant for the dehumidification/conditioning of air" , International application published under the patent cooperation treaty (PCT) WO 2012/042553 Al, % April 2012.

6. C. Isetti, E. Nannei, B. Orlandini, "Three- fluid membrane contactors for improving energy efficiency of refrigeration and air-handling systems" Int. J. of Ambient Energy.

7. Isetti, C.,Lazzari, S., Orlandini, B. " A new three-fluid plane membrane contactor for improving energy efficiency of climate control systems." Membranes for Liquid Separation and water Treatment: Environmental Applications and Future Perspectives GEAM, Turin, 10-11 October 2013.

In the foregoing, the preferred embodiments of the present inventions have been described and variations to the invention have been suggested, but it is to be understood that those skilled in the art will be able to modify and change them without thereby falling outside the relevant scope of protection as defined in the appended claims.