MX2008006879A - Dewpoint cooling device - Google Patents

Abstract

The invention relates to a device for cooling an airflow, comprising at least one cooling channel with an inflow opening for the airflow for cooling and an outflow opening for the cooled airflow, at least one evaporating channel separated from the cooling channel by a transfer wall and having an inflow opening, which is connected to the outflow opening of the cooling channel, and an outflow opening, means for wetting the side of the transfer wall directed toward the evaporating channel, and means for dehumidifying the airflow in the cooling channel. The dehumidifying means can comprise a polymer with lower critical solution temperature (LCST polymer) with which the side of the transfer wall directed toward the cooling channel can be covered or from which it can be manufactured. The cooling device can further have means for regenerating the dehumidifying means.

Description

COOLING DEVICE IN CONDENSATION POINT FIELD OF THE INVENTION The present invention relates to a device 5 for cooling an air flow, comprising at least one cooling channel with an inlet flow opening for the air flow to cool and a flow opening of outlet for the cooled air flow, at least one evaporation channel separated from the channel cooling by a transfer wall and having an inlet flow opening, which is connected to the outlet flow opening of the cooling channel, and an outlet flow opening, and means for moistening the side of the wall transfer directed towards the evaporation channel Said device, with which an air flow can be cooled indirectly through evaporation and which is also referred to as "condensation point cooler" is known in the American patent 4,002,040. BACKGROUND OF THE INVENTION The known cooling device assumes the shape of a cross-flow heat exchanger with a number of groups of cooling channels mutually ? S parallel and a number of groups of evaporation channels which, similarly, are mutually parallel and which run perpendicular to the cooling channels. A group of cooling channels here is attached in each case to two groups of evaporation channels on either side, and vice versa, where it is obtained as if it were a layered structure of the heat exchanger. The walls that form the division between the cooling channels and the evaporation channels, and which then serve for the transfer of heat (or cold) between them, are manufactured from a material that conducts heat very b in, such like aluminum for example. The walls of the evaporation channels, also including the walls that form the division between the evaporation channels and the cooling channels, are covered with a material that can retain moisture. Arranged above the evaporation channels are wetting means in the form of periodically operating atomizers which spray a quantity of water on the walls with the moisture retention material. In the known cooling device, air for cooling, for example ambient air, is carried by a fan and forced through the cooling channels. From the cooling channels, the cooled air flows, for example, into a space for ventilation.

When part of the air leaves the cooling channels, for example one third of the volume flow, it is nevertheless separated from the main flow and guided to the evaporation channels. There, the cooled air flows along the wet walls, where moisture is evaporated and entrained in the air flow. The evaporation of moisture results in a reduction in the temperature of the walls. Due to the good heat conduction of the transfer walls, this also results in a reduction of temperature in the cooling channels, where the air flow is then cooled.

SUMMARY OF THE INVENTION In comparison, for example, with an air conditioning installation, this known cooling device, on the basis of indirect evaporation, has the advantage that air cooling requires only low power. In addition, this cooling device has fewer moving parts, so it can be manufactured and installed in a simple way and at a low cost. In addition, cold generation agents are not needed. In comparison with direct evaporation coolers, the cooling device that operates in a Indirect has the advantage that air cooling does not involve an increase in air humidity. The dry cooled air sumina stro results in a pleasant climate in the cooled space. With said cooling device operating indirectly, the air can also be cooled to a lower temperature than would be possible with a direct evaporation cooler. In situations where the direct evaporative cooler can not cool the air beyond the so-called "moist bulb" temperature, the indirectly operating evaporative cooler can cool the air to the so-called "condensation point," which is the For this reason, the known cooling device is also referred to as a dew point cooler. The object of the invention is now to improve a cooling device of the type described above so that the flow of supplied air can be further cooled with it, and that even a more pleasant indoor climate can be obtained. According to the invention, this is achieved in said cooling device by means of the dehumidification of the air flow in the cooling channel. By extracting moisture from the air for cooling, this air can absorb more moisture in the evaporation channel, where an amount The larger heat of evaporation is extracted from the wall and the temperature of it then decreases further. The preferred dehumidifying media comprises a polymer with a lower critical solution temperature (LCST polymer). This polymer is soluble in water up to the critical temperature and, thus, retains moisture. The stability of the polymer in the dissolved state is guaranteed here by suitably chosen crosslinking means. A simple embodiment of the cooling device, according to the invention, is obtained when the side of the partition wall facing the cooling channel is at least partially covered with or is made of an LCST polymer. The side of the inflow of, or each cooling channel could then, for example, be covered with an LCST polymer strip. Of course it is also possible to contemplate that all the walls of, or each cooling channel is completely covered with this. material . The LCST polymer can conveniently be chosen from the group consisting of polyoxazoline, po 1 i (dimeti 1 am not et platelet) (p (DMAEMa) and pol (N-isopropylacrylamide) (pNiPAAm) These are all polymers They can extract from the air and retain a relatively large amount of moisture.

The cooling device, according to the invention, is preferably further provided with means for regenerating the dehumidifying means. The effectiveness of these dehumidification means will, after all, decrease as more moisture is extracted from the inflow air and, therefore, saturated. This moisture can be released from the dehumidification means by then activating the regeneration means, where the original effectiveness is restored. In a structurally and operationally simple mode of the cooling device, the regeneration means is adapted to periodically heat the LCST polymer above the critical solution temperature. Because said polymer is characterized by its low critical solution temperature, usually in the order of 60 to 70 ° C, simple heating elements may be sufficient in order to avoid regeneration which results in the humidification of the air flow for cooling, the regeneration means are preferably adapted to collect and discharge, from the cooling channel, moisture released by the LCST polymer during regeneration. A particularly efficient cooling device is then obtained when the regeneration are adapted to guide the collected moisture to the humidifying media. Only a small amount of water is needed for the purpose of humidifying the evaporation channels.

BRIEF DESCRIPTION OF THE FIGURES The invention will now analyze on the basis of two embodiments, wherein reference is made to the appended figures, in which: Figure 1 shows a schematic view of the air flow through a cooling device according to the invention, which operates in cross flow, Figure 2 is a perspective detail view of a part of the cooling channels and evaporation channels of the cooling device of Figure 1, Figure 3 is a sectional top view of an alternative embodiment of the cooling device, and Figure 4 is a cross section along the 1-line IV-IV in 1 to Figure 3.

DETAILED DESCRIPTION OF THE INVENTION A device 1 (FIG. 1) for cooling an air flow comprises a number of groups of mutually parallel cooling channels 2 separated by the partition walls 7 (FIG. 2), with an inlet flow opening for the air flow Al for cooling and an outlet flow opening for the cooled air flow A2. The inlet flow openings are, for example, connected to the external environment S, although the outflow openings open into a space for cooling R The flow of air, through the cooling device 1, is provided by a fan 5. The cooling device 1 further comprises a number of groups of evaporation channels 3 separated from the cooling channels 2 by the transfer walls 4. The evaporation channels 3 are mutually separated by the dividing walls 8. The inlet flow openings of the evaporation channels 3 are connected to the outflow openings of the cooling channels 2, although the outflow openings of the channels of the cooling channels 2 are connected to each other. cooling 3 flow into the external environment S. Due to the connection between cooling channels 2 and evaporation channels 3, a partial flow A3 is separated from the flow of cooled air A2 and is guided through the evaporation channels 3. After passing through the evaporation channels, the then moistened air flow A5 is blown towards the outside environment S. The relationship between the main air flow A4, which is eventually guided to the cooling space R, and the separated partial flow A3 is determined by, among other factors, the dimensions of the cooling channels and the evaporation channels, and can be example, 2: 1. The cooling device 1 is further provided with means 6 for moistening the evaporation channels 3 and, in particular, the transfer walls 4. These wetting means 6 here comprise an atomizing tube 9 with a number of openings 10 and a duct of feed 11 through which water is conveyed from a collection vessel 12 which is below the evaporation channels 3 to the atomization tube 9 using a pump (not shown here). In order to prevent the wetting means 6 from having to operate continuously, the walls 4, 8 of the evaporation channels 3 are covered with a material 13 which retains moisture, for example, an absorbent cloth or a ceramic metal coating . Until now, the cooling device 1 it remains by much of a conventional structure. In order to increase the efficiency of the cooling device, and thus achieve an additional cooling of the inflow of air. To what is possible with conventional cooling devices, the invention proposes to dehumidify this flow of air. input air Al. The ability of the separate air flow A3 to absorb moisture here increases, so that more moisture can be evaporated in the evaporation channels 3 and a greater amount of evaporation heat can then be extracted from the transfer walls In this way, the transfer walls 4 become colder than in conventional cooling devices, so that a higher cooling capacity is achieved. In the embodiment shown, the means 14 for dehumidifying the flow of air to be cooled take the form of a polymer material with a lower critical solution temperature (LCST polymer), which are accommodated as the cover layer 15 in the walls 4, 7 of the cooling channels 2. Like the LCST polymer, it is possible to contemplate a material such as polyoxazole, poly (dimethylamine ethyl methacrylate) (p (DMAEMa) and poly (N-isopropylacrylamide) (pNiPAAm Although all walls 4, 7 of the cooling channels here are completely covered with the LCST polymer, it is also possible to contemplate the sufficiency with the coverage of only a part of the walls, for example, the vertical transfer walls 4. It is also possible to contemplate the LCST polymer that is accommodated only over a part of the length of the channels 2, for example, on the inlet side thereof (FIG. 3), or even in a part of the inlet flow of the cooling device 1 located upstream of the actual cooling channels. LCST polymer 15 on the walls 4, 7 absorbs moisture from the air flowing through, and here, it passes to the solution. The dissolved polymer layer retains its stability due to the presence of conveniently chosen crosslinkers. As mentioned, the moisture absorption capacity of the air flow A3 in the evaporation channels 3, and with it the cooling capacity, increases due to the air dcshumidification. Furthermore, this results in a higher degree of comfort because the flow of cooled air A2 supplied to the space R is drier. As more moisture is absorbed in the LCST 15 polymer layer and this layer then becomes more saturated, the effectiveness of the media decreases. dehumidification 14 In the embodiment shown, the cooling device 1 is then also provided with means 16 for generating the polymer layer 15. These regeneration means 16 are adapted to periodically heat the LCST polymer above its critical solution temperature. because this critical temperature is relatively low, and amounts, for example, to the order of 60 to 70 ° C, relatively simple, it is possible that low-power heating elements 17 are sufficient. The construction and operation of said heating elements is described and shown in the unreleased Netherlands patent application 1030149 of the applicant. When the LCST 15 polymer is heated above the critical solution temperature, it leaves the solution and the moisture L is then released once again. This moisture L then flows along the walls 4, 7 in order to avoid the undesired wetting of the inlet flow air As a result, the regeneration means 16 are further adapted to collect, discharge from the cooling channels 2, this moisture L delivered during the regeneration. For this purpose, the cooling channels 2 can , for example, be tilted down to a certain extent so that moisture L flows to the lowest point of the cooling channels 2. In the embodiment shown, there is a collection container 18. The latter is in turn connected to the collection container 12 of the humidification means 6. The water consumption of the cooling device 1 is thus reduced, thereby guiding Moisture means moisture L extracted from the inflow air. Instead of crossing each other, the cooling channels 2 and evaporation channels 3 can also run parallel, but in opposite directions (Figures 3 and 4) This is then a counter flow cooler. This scenario has the advantage that it is more prolonged, so that a more intensive heat exchange contact between the air flow to which it is to be cooled and the evaporation flow A3 is possible, although the invention was previously analyzed on the basis of a number of modalities, it will be apparent that it can be modified in many ways. The scope of the invention is then defined only by the following claims.

Claims (2)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1 - . 1 - A device for cooling an air flow, comprising: at least one cooling channel with an inlet flow opening for the air flow for cooling and an outlet flow opening for the cooled air flow, at least one evaporation channel separated from the cooling channel by a transfer wall and having an inlet flow opening, which is connected to the outlet opening of the cooling channel, and an outlet flow opening , and means for wetting the side of the transfer wall directed towards the evaporation channel, characterized by the means for dehumidifying the air flow in the cooling channel.

2 - The cooling device according to claim 1, characterized in that the means of Dehumidification comprises a polymer with a lower critical solution temperature (LCST polymer). 3. The cooling device according to claim 1 or 2, characterized in that the side of the transfer wall directed towards the cooling channel is at least partially covered with, or is manufactured from an LCST polymer. 4. The cooling device according to claim 2 or 3, characterized in that the LCST polymer is chosen from the group comprising poloxazolam, poly (dimethylamine ethyl methacrylate) (p (DMAEMa) and poly (N-isopropyl acrylamide). (pNiPAAm) 5. The cooling device according to any of claims 2-4, characterized by the means for regeneration of the demodulation means 6. - The cooling device according to claim 5, characterized because the regeneration means are adapted to periodically heat the LCST polymer above the critical solution temperature 7 - The cooling device according to claim 5 or 6, characterized in that the regeneration means are adapted to collect and discharge the channel moisture cooling provided by the LCST polymer during regeneration. 8. The cooling device according to claim 7, characterized in that the regeneration means are adapted to guide the collected moisture to the wetting means.