WO2025004018A1

WO2025004018A1 - Air dehumidifier

Info

Publication number: WO2025004018A1
Application number: PCT/IB2024/056426
Authority: WO
Inventors: Alberto Gasparini
Original assignee: Fral Srl
Priority date: 2023-06-30
Filing date: 2024-07-01
Publication date: 2025-01-02
Also published as: IT202300013728A1

Abstract

An air dehumidifier comprises an inlet, an outlet for a processed air flow, at least a first path extending between said inlet and said outlet and along which an evaporator is arranged which is configured to act on a first portion of air flow to be processed. The dehumidifier further comprises first heat exchange means, first ventilation means to at least a second path, separate with respect to the first path, for a second portion of the air flow to be processed. The second path is configured to pass through respective second heat exchange means and at least second ventilation means. The dehumidifier further comprises heat transfer means which are configured to cool the first portion of air flow, upstream of the evaporator, and to heat the first portion of air flow downstream of the evaporator.

Description

Air dehumidifier

DESCRIPTION

The present invention relates to an air dehumidifier with increased efficiency and performance.

In the technical sector of reference, dehumidifiers are known for processing air to be re-fed into a room, to improve the thermal and hygrometric comfort thereof.

In a conventional dehumidifier, there is a compressor which sends hot compressed refrigerant gas to a condenser, which receives the refrigerant gas and condenses it. A lamination member receives the liquid refrigerant from the condenser and expands it, lowering the temperature and pressure of the liquid. An evaporator receives the cold liquid refrigerant from the lamination member and makes it evaporate into cold refrigerant gas. The evaporated refrigerant discharged from the evaporator is sent to the compressor, closing the cycle. The air flow to be processed is directed through the evaporator to cool the air below the dew point so that the water vapour in the air is condensed to liquid to dehumidify it. The air is then passed through the condenser to be heated.

In order to increase the efficiency of dehumidifiers, it is known to use systems which transfer heat between before and after the evaporator, e.g., cross-flow air-to-air heat exchangers, which envisage pre-cooling the air flow upstream of its passage through the evaporator. The pre-cooled air then passes in the evaporator and is subsequently reheated in the same heat exchanger in a subsequent step. The air flow discharged from the heat exchanger is then passed through the condenser to be post-heated and re-fed into the room.

Such a solution has some limitations, including air-side pressure losses at this system, and for which the electrical consumption for ventilation is high and much higher with respect to the conventional systems without heat recovery.

Furthermore, the system tends to work with a higher condensation temperature with respect to that of the conventional system, with a consequent increase in the electrical consumption of the compressor.

Some solutions known to date also envisage the presence of ventilation means, to generate the air flow at the inlet and outlet of the device, and/or an additional heat exchanger placed upstream of the condenser and downstream of the previous exchanger, from which it receives the heated air flow. The air discharged from the additional heat exchanger is passed through the condenser. This solution allows the hot liquid discharged from the condenser to be further sub-cooled before it is sent to the lamination member, increasing the efficiency of the dehumidifier.

In order to further increase the efficiency of the dehumidifier, other solutions envisage the addition of an air flow upstream of the condenser to the system just described, which is added to the air flow discharged from the additional heat exchanger. This solution allows to increase efficiency with respect to the previous system. A higher air flow to the condenser allows the condensation temperature to be lowered, resulting in lower electric consumption for the compressor, whereas with heat recovery, the system tends to work with a higher condensation temperature with respect to a conventional system.

However, this solution does not overcome the drawback of high air-side pressure losses, which occur where a heat recovery system is present.

Further examples of known solutions are described in EP 4 056 909 Al and CN 108 826 508 A. The technical problem underlying the present invention is to improve the prior art in one or more of the aspects indicated above.

In the context of such a problem, one aim of the present invention is to propose a dehumidifier designed to work at high efficiency.

Another aim of the invention is to propose a dehumidifier thanks to which it is possible to overcome the drawback of air-side pressure losses due to the presence of a heat recovery system, such as a cross-flow heat exchanger.

A further aim of the invention is to propose a dehumidifier thanks to which the overall electric consumption of the device itself can be reduced.

It is further an aim of the present invention to provide a dehumidifier which is capable of improving the known solutions in terms of performance and/or energy efficiency, within the context of a rational and relatively low-cost solution.

This problem is at least partly solved and one or more of these aims are at least partly achieved by the invention by means of a dehumidification device comprising:

- at least one inlet for an air flow to be processed,

- at least one outlet for a processed air flow,

- at least a first path for at least a first portion of said air flow to be processed. Preferably the device comprises heat transfer means which are configured to cool said first portion of air flow to be processed, upstream of said evaporator, and to heat said first portion of air flow downstream of said evaporator.

The air flow to be processed herein means an air flow which undergoes a change in temperature and/or humidity level when passing through the dehumidifier. Processed air flow, on the other hand, means an air flow which has already undergone the aforesaid modification.

Preferably, the dehumidifier includes at least first heat exchange means.

Preferably, the dehumidifier comprises first ventilation means for causing said first portion of air flow to pass through said first heat exchange means.

Preferably, the dehumidifier also comprises at least a second path, which is physically separated from said first path, for ate least a second portion of said air flow to be processed, which is configured to pass through respective second heat exchange means and at least second ventilation means in order to cause said second portion of air flow to pass through said second heat exchange means.

The Applicant has noted that it is thereby possible to bring a certain air flow to second heat exchange means, with relatively low pressure losses and consequently a limited overall electrical consumption necessary for ventilation. Further preferred, but not exclusive, features of the invention are also defined in the dependent claims.

Preferably, the refrigeration circuit comprises at least one compressor, at least a first condenser, at least one lamination member, at least one evaporator, said first path being configured to pass through said refrigeration circuit at said first condenser and said evaporator.

Preferably, the first heat exchange means are defined by said first condenser. By means of the first ventilation, a first portion of the air flow to be processed is caused to pass through the condenser of the refrigeration circuit.

According to another aspect of the invention, the second heat exchange means are defined by a second condenser.

Therefore, by means of the second ventilation, a second portion of air flow to be processed is caused to pass through the second condenser.

Thereby, a second portion of air flow to be processed is brought through a second condenser to be heated.

According to still another aspect of the invention, the heat transfer means are configured so as to intercept said the first path and are configured to cool said first portion of air flow to be processed, upstream of said evaporator, and to heat a second flow of the same air flow downstream of the same evaporator. Preferably, the heat transfer means comprise a cross-flow heat exchanger.

Thereby, the air flow moving in the first path is heated by the heat transfer means to then also be post-heated by passing through the first condenser.

According to a further aspect of the invention, the dehumidifier comprises auxiliary heat transfer means configured for the passage of a heated air flow discharged from said cross-flow heat exchanger.

Preferably, said auxiliary heat transfer means comprise an additional heat exchanger.

Thanks to this feature, it is possible to sub-cool the refrigeration circuit liquid discharged from the first condenser before it is sent to the lamination member. In some possible embodiments, the first heat exchange means and the second heat exchange means are defined by different portions of the same heat exchanger, said different portions being configured to be passed through by said portion of air flow and by said second portion of air flow, respectively.

In other embodiments, the two heat exchangers can consist of two separate heat exchangers.

Preferably, said separate portions of the same heat exchanger comprise said first condenser and said second condenser, respectively. Even in the case of separate heat exchangers, the first heat exchange means and the second heat exchange means comprise said first condenser and said second condenser, respectively.

Advantageously, in some embodiments preferably at least one control unit is present for said first ventilation means and said second ventilation means.

Such a control unit is preferably configured to independently control one or the other of said first and second ventilation means so as to regulate said first portion of air flow and said second portion of air flow, respectively.

By means of such a control unit, it is therefore possible to proportion the air flows to be processed and the processed air flows according to the discharge parameters of the processed air required by the environment, and/or the fundamental parameters of the refrigeration circuit with the aim of energy optimisation.

A room is defined as the space in a home, office, private place, etc. into which the air processed by the dehumidifier is to be fed.

Preferably, said second path is separated from said first path by means of a partition wall so as to keep said first air flow independent from said second air flow.

In some embodiments, the dehumidifier comprises channelling means configured so as to channel said first processed air flow and/or said processed air flow into a further flow.

In some embodiments, said channelling means comprise a common outlet for both processed air flows.

It will be understood, however, that the channelling means can only involve a single flow and, consequently, one of the two outlets will not be affected by the channelling means.

Preferably, said channelling means comprise additional ventilation means which allow to increase the pressure of the processed air flow, thus favouring the transfer thereof into ducts through which air is transferred to the users.

In preferred embodiments, the additional ventilation means are also connected to the control unit and can be operated independently of the first and second ventilation means, thus enabling the 'booster' action described above when required by the conditions of use.

Further features and advantages of the invention will become clearer from the following detailed description of a preferred, but not exclusive, embodiment example illustrated, by way of non-limiting example, with reference to the appended drawings in which:

- Figure 1 is a schematic depiction of the dehumidifier with the air paths therein;

- Figure 2 is a schematic depiction of the dehumidifier of the present invention according to an alternative embodiment.

With reference to the above-mentioned figure, the dehumidifier according to the invention is comprehensively indicated with reference number 10.

The dehumidifier 10 can be installed to process the air to be re-fed into a room, controlling the humidity level and temperature thereof. Such a type of device is particularly suitable for processing the air in public or private places frequented by people.

The dehumidifier 10 illustrated comprises an inlet 11 for air flows Al, A2 to be processed and an outlet 12 for processed air flows Bl, B2.

As will be described in more detail below, two physically distinct inlets and outlets can be provided in input and output, however, it is understood that advantageously, only one inlet and one outlet is envisaged provided from a fluiddynamic point of view.

In fact, the inlet 11 is preferably configured so as to divide a common air flow to be processed into two portions Al, A2, and the inlet is in turn preferably configured so as to feed the two portions of processed air Bl, B2 into a single environment anyway, thus again obtaining a common flow.

The dehumidifier 10 advantageously comprises at least a first path Pl for at least a first portion of air flow to be processed Al, a refrigeration circuit including first heat exchange means 13 and first ventilation means 14 for causing the first portion of air flow Al to pass through the first heat exchange means 13.

In the attached figure, some components of the refrigeration circuit are schematically shown, which in a manner known per se comprises a compressor (not shown), a first condenser 13, a lamination member (also not shown), and at least one evaporator 15.

The first heat exchange means 13 are defined by the first condenser, which, therefore has been consistently referred to in the present text with the same reference number.

As illustrated, the first path Pl is configured to pass through the refrigeration circuit at the first condenser 13 and the evaporator 15.

The dehumidifier 10 further comprises a second path P2 for at least a second portion of air flow to be dehumidified A2. In some embodiments, the second path P2 can be physically separated from the first path Pl. The second path P2 is configured to pass through respective heat exchange means 16 and at least second ventilation means 17 to cause the second portion of air flow A2 to pass through the second heat exchange means 16.

It is noted that, in preferred embodiments, the inlet 11 is configured so that said air to be processed is divided into said first portion Al and said second portion A2 when fed into the dehumidifier.

The first ventilation means 14 and the second ventilation means 17 both consist of fans.

Thanks to the second fan, i.e., to the second ventilation means 17, a large amount of air can be sent to the second heat exchange means 16 with low pressure drops.

The second heat exchange means 16 are defined by a second condenser, therefore referred to in the rest of the text with the same reference number.

The dehumidifier 10 also comprises heat transfer means 18 which, intercepting the first path Pl, is configured to cool the first portion of air flow to be processed Al, upstream of the evaporator 15, and to heat a second flow of the same air flow downstream of the same evaporator 15. In preferred embodiments, the heat transfer means 18 comprise a cross-flow heat exchanger of a known type. According to the path Pl, from one side of the heat exchanger 18 the first portion of air flow Al is caused to pass through it at special channels until it is discharged from the opposite side, from where it is caused to pass through the evaporator 15 of the refrigeration circuit, in which it is cooled. In succession, the air discharged from the evaporator 15 is led back into the heat exchanger 18, passing through it at other channels adjacent to the previous ones, with which the heat exchange occurs. In passing through the channels, the air is precooled upstream of the evaporator 15, while when crossing the other channels, it is heated downstream of the same evaporator 15. The same concepts can be applied to different types of heat transfer means 18, even those not based on cross-flow heat exchangers.

In fact, it is noted that generally, the heat transfer means 18 are configured to cool the first portion of air flow to be processed Al, upstream of the evaporator 15, and to heat the same first portion of air flow Al downstream of the evaporator 15. This therefore allows to obtain the desired heat transfer in the context of the present dehumidifier.

In other words, the heat transfer means 18 are arranged between a location upstream and downstream of said evaporator 15.

In the dehumidifier 10 according to the invention, auxiliary heat transfer means 19 can also be present, preferably comprising an additional heat exchanger, configured for the passage of the heated air flow discharged from the heat transfer device 18, still following the path Pl.

The second path P2 is independent of the first path Pl and does not intercept the means crossed by the first path Pl.

The first heat exchange means 13 and the second heat exchange means 16, are defined, in the case illustrated, by separate portions of the same heat exchanger, which are configured to be passed through by the first portion of air flow Al and the second portion of air flow A2, respectively.

As mentioned above, such separate portions of the same heat exchanger comprise the first condenser and the second condenser, respectively, indicated with 13 and 16 in the illustrated example.

The dehumidifier 10 advantageously comprises a control unit 21 of the first ventilation means 14 and the second ventilation means 17, which is configured to independently control one or the other of the first and second ventilation means 14, 17 so as to regulate the first portion of air flow Al and the second portion of air flow A2, respectively.

Thereby, the two portions of air to be processed, Al and A2, can be managed independently of each other by means of the control unit, according to pre-set parameters of the processed air, in particular the temperature and humidity level present therein, and/or the fundamental parameters of the refrigeration circuit.

In the example illustrated and as described above, the first and the second heat exchange means 13 and 16 are defined by separate portions of the same heat exchanger.

The second path P2 can be separated from the first path Pl by means of a separation wall 20, or other physical separation element.

However, it will be appreciated that it may be possible for the first air flow Al to be sufficiently separated from the second air flow A2 even in the absence of the wall 20, which may possibly form a physical separation.

If present, such a separation wall 20 extends to separate the separate portions of the heat exchanger, defining a separation between the first condenser 13 and the second condenser 16.

At the outlet of dehumidifier 10, the two processed air flows , Bl and B2 come together, generating a single processed air flow.

Advantageously, the first processed air flow Bl, following the first path Pl, has undergone dehumidification and possible heat treatment, while the second processed air flow B2, following the second path P2, has undergone a heat treatment.

The operation of the dehumidifier according to the invention is evident from what has been described and illustrated and, in particular, it is evident how the creation of a second path for the air flow, separate from the first path which passes through the refrigeration circuit, allows to limit pressure drops and electric consumption with respect to the solutions known and diffused to date, thus increasing the overall yield of the dehumidifier.

Thanks to the second ventilation means, present in the second path P2, it is possible to send the desired amount of air flow A2 to the second condenser, i.e., to the second heat exchange means 16, with low pressure drops, resulting in low electric consumption necessary for ventilation.

In alternative embodiments, the dehumidifier 10 may also comprise channelling means 22 configured so as to channel the first processed air flow Bl and the second processed air flow B2 into a single flow B3.

Such a flow B3 is advantageously channelled towards a common outlet 12A for both processed air flows.

Although in the embodiment illustrated in the figure, the channelling means 22 involve both flows, it will be appreciated that they can only involve one flow between the first flow Bl and the second flow B2.

In this case, the flow involved will be channelled towards a further outlet, while the other flow will simply be discharged from the relative outlet 12.

In order to provide sufficient pressure to the air flow, the channelling means 22 can comprise additional ventilation means 23 which allow the pressure of the processed air flow to be increased, thus favouring the transfer thereof into ducts through which air is transferred to the users.

The additional ventilation means 23 can also be connected to the control unit 21 and can be operated independently of the first and second ventilation means. Thereby, the additional ventilation means can be operated only if necessary, acting as a 'booster' for the dehumidifier.

It is understood that if the channelling means involve only one of the two flows Bl, B2, the additional ventilation means will act on the flow involved, while the other flow will be fed at the discharge pressure from the outlet 12.

Still alternatively, each flow Bl, B2 can be associated with respective channelling means, each of which in turn comprises respective additional ventilation means 23 acting individually on the two flows Bl and B2.

It should be noted that the dehumidifier benefits from the advantages related to using the heat transfer means, with a significantly increase in system efficiency.

It should also be noted that with respect to the known solutions using a crossflow exchanger, such a solution generates a higher yield.

In practice, it has been found that the invention achieves the intended task and aims by making a dehumidifier capable of working at high efficiency, obviating the drawback of air-side pressure drops and limiting the overall electric consumption of the device itself.

The invention is susceptible to numerous modifications and variations, in addition to those described, all of which fall within the scope of the inventive concept.

Claims

1. An air dehumidifier (10) comprising:

- at least one inlet (11) for an air flow (Al, A2) to be processed,

- at least one outlet (12) for a processed air flow (Bl, B2),

- at least a first path (Pl) for a first portion of the air flow (Al) to be processed which extends between the at least one inlet and the at least one outlet (12) and along which an evaporator (15) which is configured to act on the first portion of the air flow (Al) to be processed is arranged,

- at least first heat exchange means (13),

- first ventilation means (14) for causing the first portion of air flow (Al) to be processed to pass through the first heat exchange means (13), the dehumidifier (10) is characterized in that it comprises at least a second path (P2), which is different from the first path (Pl), over a second portion of the air flow (A2) to be processed, which is configured to pass through respective second heat exchange means (16) and at least second ventilation means (17) in order to cause the second portion of air flow (A2) to pass through the second heat exchange means (16),

- heat transfer means (18) which are configured to cool the first portion of air flow (Al) to be processed, upstream of the evaporator (15), and to heat the first portion of air flow downstream of the evaporator (15).

2. A dehumidifier (10) according to claim 1, wherein the heat transfer means (18) are arranged between a location upstream and a location downstream of the evaporator (15).

3. A dehumidifier (10) according to any one of the preceding claims, wherein the at least first heat exchange means (13) are included in a refrigeration circuit.

4. A dehumidifier (10) according to claim 3, wherein the refrigeration circuit comprises at least one compressor, at least a first condenser, at least one lamination member, at least one evaporator (15), the first path (Pl) being configured to pass through the refrigeration circuit at the first condenser and the evaporator (15), the first heat exchange means (13) preferably being defined by the first condenser.

5. A dehumidifier (10) according to any one of the preceding claims, wherein the second heat exchange means (16) are defined by a second condenser.

6. A dehumidifier (10) according to any one of the preceding claims, wherein the heat transfer means comprise a heat exchanger (18) with intersecting flows which is configured, by intercepting the first path (Pl), to cool the first portion of air flow (Al) to be processed upstream of the evaporator (15) and to heat a second flow of the same air flow downstream of the same evaporator (15).

7. A dehumidifier (10) according to any one of the preceding claims, comprising auxiliary heat transfer means (19) configured for the passage of a heated air flow being discharged from the heat transfer means (18).

8. A dehumidifier (10) according to one or more of the preceding claims, wherein the first heat exchange means (13) and the second heat exchange means (16) are defined by different portions of the same heat exchanger, the different portions being configured to be passed through by the first portion of air flow (Al) to be processed and by the second portion of air flow (A2) to be processed, respectively.

9. A dehumidifier (10) according to any one of the preceding claims, wherein there is present at least one control unit for the first ventilation means (14) and the second ventilation means (17).

10. A dehumidifier (10) according to the preceding claim, wherein the control unit is configured to independently control one or other of the first and second ventilation means (14, 17) so as to regulate the first portion of air flow (Al) to be processed and the second portion of air flow (A2) to be processed in order to optimize the energy and/or in order to control humidity and temperature of the environment.

11. A dehumidifier (10) according to any one of the preceding claims, wherein the second path (P2) is separated from the first path (Pl) via physical separation means (20) so as to maintain the first portion of air flow (Al) to be processed independent of the second portion of air flow (A2) to be processed.

12. A dehumidifier (10) according to any one of the preceding claims, comprising channelling means (22) which are configured so as to channel the first processed air flow (Bl) and/or the second processed air flow (B2) into an additional flow (B3), wherein the channelling means include additional ventilation means (23) configured so as to increase the pressure of the additional flow (B3).

13. A dehumidifier (10) according to any one of the preceding claims, wherein the air flow to be processed is common and the inlet (11) is configured so that the air to be processed is divided into the first portion (Al) and the second portion (A2) when fed into the dehumidifier.

14. A dehumidifier (10) according to any one of the preceding claims, wherein the outlet (12) is configured to feed the first portion (Al) being discharged from the first path (Pl) and the second portion being discharged from the second path (P2) into the same environment.

15. A dehumidifier (10) according to any one of the preceding claims, wherein said outlet is common to both the first path and the second path (P2).

16. A dehumidifier (10) according to any one of the preceding claims, wherein the first ventilation means (14) and the second ventilation means (17) are arranged immediately upstream of the outlet (12).

17. A method for dehumidifying an air flow by means of a dehumidifier (10) according to any one of the preceding claims, comprising:

- Dividing an air flow to be processed into a first portion of air (Al) and a second portion of air (A2);

- Feeding the first portion of air (Al) into the first path (Pl) and the second portion of air (A2) into the second path (P2);

Processing the first portion of air (Al) and the second portion of air (A2) in the dehumidifier so as to obtain a first portion of processed air (Bl) and a second portion of processed air (B2);

- Discharging the first portion of processed air (Bl) and the second portion of processed air (B2) from the outlet (12).

18. A method according to the preceding claim, further comprising discharging the first portion of processed air (Bl) and the second portion of processed air (B2) to a common environment at which said first portion of processed air (Bl) and said second portion of processed air (B2) are combined into a single processed air flow.