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EP-4739969-A1 - TUBE BUNDLE HEAT EXCHANGER WITH OUTLET DRYING SYSTEM

EP4739969A1EP 4739969 A1EP4739969 A1EP 4739969A1EP-4739969-A1

Abstract

The present invention relates to a heat exchanger configured so that the fluid circulating in the chamber containing the tube bundle performs a first heat exchange with said tube bundle and a second heat exchange with the distribution means of said fluid in the chamber. The present invention also relates to a method of drying a fluid in a tube bundle heat exchanger.

Inventors

  • PROVENZIANI, FRANCO
  • PITRELLI, Paolo
  • DONELLO, Paolo

Assignees

  • Wieland Provides Srl

Dates

Publication Date
20260513
Application Date
20240625

Claims (15)

  1. 1. A heat exchanger (100) comprising: ■ a casing (2) defining a heat exchange chamber (3), said chamber (3) having a base region (B) and a top region (S), ■ a tube bundle (1) placed in said chamber (3) and at said base region (B), ■ distribution means (4) configured to receive internally a fluid to be sprayed in said chamber (3) and intended for a first heat exchange with said tube bundle (1 ), wherein said distribution means (4) is positioned inside said chamber (3) at said top region (S) and said casing (2) further comprises an outlet opening (21 ) of the fluid from said chamber (3), wherein said opening (21 ) is positioned downstream of said distribution means (4) according to an outlet direction (E) of the fluid so that said distribution means (4) allows a second heat exchange with the fluid exiting said chamber (3).
  2. 2. The heat exchanger (100) according to the preceding claim, further comprising pressure drop means (41 , 42) configured to establish an internal pressure difference between said distribution means (4) and said heat exchange chamber (3).
  3. 3. The heat exchanger (100) according to the preceding claim, wherein said pressure drop means comprises one or more nozzles (41 ) and/or orifices (42) carried by said distribution means (4).
  4. 4. The heat exchanger (100) according to any one of the preceding claims, wherein said distribution means (4) comprises a tubular element (40) having an outer surface (40a) of heat exchange with the fluid present in said chamber (3).
  5. 5. The heat exchanger (100) according to the preceding claim, wherein said outer surface (40a) comprises fins and/or recesses.
  6. 6. The heat exchanger (100) according to any one of the preceding claims, wherein said casing (2) carries said outlet opening (21 ) in position opposite to said base region (B).
  7. 7. The heat exchanger (100) according to any one of the preceding claims, wherein said casing (2) carries an opening (22) for supplying fluid in said distribution means (4).
  8. 8. The heat exchanger (100) according to any one of the preceding claims, further comprising fluid flow directional means (5) positioned in said exchange chamber (3) and configured to direct the exiting fluid towards said distribution means (4).
  9. 9. The heat exchanger (100) according to the preceding claim, wherein said directional means comprises a plate-like element (5) fixed to the casing (2) and oriented in such a way as to confine therebetween said base region (B) and said top region (S) through respective opposite faces (5b, 5s) of said plate-like element (5).
  10. 10. The heat exchanger (100) according to the preceding claim, wherein said base region (B) and said top region (S) are in fluid communication through one or more openings (51 ) obtained in said plate-like element (5).
  11. 11. The heat exchanger (100) according to the preceding claim, wherein said one or more openings (51 ) face said distribution means (4) and are distributed along an axis (A’) parallel to a longitudinal development axis (A) of said casing (2) and/or of said tube bundle (1 ).
  12. 12. The heat exchanger (100) according to any one of claims 9 to 11 , wherein said plate-like element (5) has a V-shaped or U-shaped profile.
  13. 13. The heat exchanger (100) according to any one of claims 9 to 12, wherein said distribution means (4) comprises one or more portions (43) projecting into said base region (B) through one or more corresponding openings (51 ) of said plate-like element (5).
  14. 14. A use of a heat exchanger (100) according to any one of the preceding claims as an evaporator.
  15. 15. Method of drying a fluid in a tube bundle (1 ) heat exchanger (100) comprising the steps of: ■ providing means for distributing the fluid (4) inside a heat exchange chamber (3) containing the tube bundle (1 ), ■ spraying the fluid onto the tube bundle (1 ) for a first heat exchange, ■ sucking the fluid according to an outlet direction (E) from said chamber (3) so as to obtain a second heat exchange with said distribution means (4).

Description

TUBE BUNDLE HEAT EXCHANGER WITH OUTLET DRYING SYSTEM DESCRIPTION Technical field of the invention The present invention relates to the field of the apparatuses for the heat treatment of fluids, in particular the apparatuses suitable to the use in industrial air conditioning systems. The present invention, more in detail, relates to a tube bundle heat exchanger, in particular an evaporator, which implements a system and a method for drying the cooling fluid flow exiting the exchanger itself. Background As it is known, the tube bundle heat exchangers have several problems affecting the size and design of the evaporator. Generally, a problem of the evaporators is that of obtaining a wished thermal efficiency, sizes and technical complexity being equal. Therefore, a technical object is to increase the thermal efficiency of the heat exchanger with structurally simple and economically advantageous solutions. Several factors affect the efficiency of these machines. For example, one of the main operating limits of the evaporators, such as for example in the flooded and spray type evaporators, is represented by the dragging of a liquid component in the flow for sucking the fluid used as cooling fluid. In fact, this involves a loss in the available refrigeration capacity since if, on one side, a portion of the cooling fluid exits the evaporator in liquid phase the latter could not have contributed to the heat exchange, by affecting the apparatus efficiency. In the most serious cases, the liquid dragging involves further significant damages to the circuit placed downstream of the suction, in particular to the mechanics of the compression units. A known solution to avoid the liquid dragging provides to increase the overheating of the fluid during suction at the evaporator exit. This solution, although very effective and simple to be implemented (it does not require additional components) is very expensive since it involves an oversizing of the evaporator. In order to obtain the overheating of the cooling fluid, in fact, it is necessary to increase the heat exchange surfaces and then the overall sizes of the evaporator, by increasing considerably the costs. It is also known to size the evaporator in order to limit the liquid dragging and to keep the gas flows within predetermined conditions. Even in this case one proceeds with oversizing the evaporator and mechanical elements are used, suitable to uniform the inner gas flows. As for the previously described solution, by introducing additional inner components and/or by oversizing the sizes to reduce the suction flow speed, the evaporator cost increases. Other solutions provide the use of “intermediate” heat exchangers in order to dry the suction flow. In other words, the use of an additional heat exchanger, outer or inserted in the evaporator itself, is provided, in which the hot liquid coming from the high-pressure line circulates and so as to allow an additional heat exchange with the humid gas exiting the evaporator. At last, it is also known to use liquid separating means installed downstream of the suction, but upstream of the inlet in the compression units. Although these are generally cheap solutions, which operate well in protecting the compressor against high liquid dragging transients, these configurations are not useful in case the liquid dragging is constantly above a limit threshold. Moreover, although each one of the above-illustrated solutions can have advantages, all of them have in common the drawback of a not negligible cost increase, associated to the refrigerator implementation. Still, an additional factor affecting the exchanger efficiency is linked to the homogeneous spraying of the cooling fluid in general, even in particular of its liquid phase, on the tube bundle. In fact, if such homogeneous spraying does not take place, the wished heat exchange is not obtained. In standard flooded type evaporators the cooling fluid, generally sprayed from the bottom, submerges the tube bundle by favouring the liquid interaction with the exchange tubes to the detriment of the overall amount of charge the same. Within the evaporators of so-called “falling film” and “spray” type, according to the known solutions, the distribution of the cooling fluid mainly takes place from a portion above the tube bundle, in a spraying direction traditionally from top towards the bottom. However, this type of spraying does not solve the technical problem of spraying the fluid so that the tube bundle is wetted thereby uniformly. In fact, it is unquestionable that this configuration allows to wet sufficiently well the surface of tubes placed directly facing the spraying devices or generally the surface of the upper portion of the bundle, but it is not as effective in wetting the tube bundle portion placed therebelow. There are also solutions providing a configuration interposed between spraying devices and pipes, in a “rhombus”-like arrangement which provides each spraying dev