GB2457599A - Shell and tube heat exchanger - Google Patents
Shell and tube heat exchanger Download PDFInfo
- Publication number
- GB2457599A GB2457599A GB0903234A GB0903234A GB2457599A GB 2457599 A GB2457599 A GB 2457599A GB 0903234 A GB0903234 A GB 0903234A GB 0903234 A GB0903234 A GB 0903234A GB 2457599 A GB2457599 A GB 2457599A
- Authority
- GB
- United Kingdom
- Prior art keywords
- heat exchanger
- coating
- tube
- inner tube
- aluminium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000011248 coating agent Substances 0.000 claims abstract description 26
- 238000000576 coating method Methods 0.000 claims abstract description 26
- 239000004411 aluminium Substances 0.000 claims abstract description 22
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 230000007797 corrosion Effects 0.000 claims abstract description 13
- 238000005260 corrosion Methods 0.000 claims abstract description 13
- 238000005452 bending Methods 0.000 claims abstract description 5
- 229920003020 cross-linked polyethylene Polymers 0.000 claims abstract description 5
- 239000004703 cross-linked polyethylene Substances 0.000 claims abstract description 5
- 239000004952 Polyamide Substances 0.000 claims abstract description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000007743 anodising Methods 0.000 claims abstract description 4
- 230000004888 barrier function Effects 0.000 claims abstract description 4
- 229920002647 polyamide Polymers 0.000 claims abstract description 4
- 239000011701 zinc Substances 0.000 claims abstract description 4
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 4
- 230000001681 protective effect Effects 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 6
- 239000002861 polymer material Substances 0.000 claims description 6
- -1 Polyethylene Polymers 0.000 claims description 3
- 239000004698 Polyethylene Substances 0.000 claims description 3
- 229920000573 polyethylene Polymers 0.000 claims description 3
- 229920000642 polymer Polymers 0.000 abstract description 4
- 239000003507 refrigerant Substances 0.000 abstract description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 abstract 2
- 229910002092 carbon dioxide Inorganic materials 0.000 abstract 1
- 239000001569 carbon dioxide Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 7
- 239000012530 fluid Substances 0.000 description 3
- 239000008399 tap water Substances 0.000 description 3
- 235000020679 tap water Nutrition 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000009428 plumbing Methods 0.000 description 2
- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 1
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229910001431 copper ion Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/08—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being otherwise bent, e.g. in a serpentine or zig-zag
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/10—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically
- F28D7/14—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically both tubes being bent
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
- F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
- F28F19/04—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of rubber; of plastics material; of varnish
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
- F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
- F28F19/06—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of metal
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/06—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material
- F28F21/062—Constructions of heat-exchange apparatus characterised by the selection of particular materials of plastics material the heat-exchange apparatus employing tubular conduits
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
A shell and tube heat exchanger 1 comprises an inner tube 2 made of aluminium and is provided with a coating on its outer face that is sacrificial, protective or passive in relation to corrosion, and an outer shell 3 surrounding the inner tube 2 and is made of a polymer. Heat exchanger 1 may be a gas cooler/evaporator in water heat pump systems with refrigerants working at relatively high pressures such as carbon dioxide. The coating may be a Polyamide polymer forming an impervious barrier between water and aluminium, the coating may be sacrificial zinc coating or a sol gel coating based on anodising treatment to passivate a surface of the inner tube 2. Outer shell 3 may be a cross linked Polyethylene tube (PEX tube). Inner tube 2 may be an extruded aluminium tube with outer longitudinal fins (4, fig 2) and have internal enhancements to avoid collapse of the inner tube 2 during narrow bending radius applications. The heat exchanger 1 arrangement reduces galvanic corrosion of the aluminium.
Description
Tube and shell heat exchanger The present invention relates to a tube and shell heat exchanger for vapour compression systems, in particular water heat pump systems with refrigerants working at relatively high pressures such as CO2. where potential corrosion problems will occur.
The heat exchanger according to the present invention is of the kind where two fluids, of different starting temperatures, flow through the heat exchanger. One flows through the tubes (the tube side) and the other flows through an annular space outside the tubes, but inside the shell (the shell side). Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. The fluids can be either liquids or gases on either the shell or the tube side. In order to transfer heat efficiently, a large heat transfer area should be used, leading to extension of the heat transmitting surface. Such heat exchangers are commonly made of stainless steel or copper or even combinations of such materials.
Aluminium is in most cases not a suitable material for residential water heat exchangers in case of direct contact between the tap water and the aluminium due to an increased corrosion potential. One of the initiating factors of the corrosion is the presence of free chlorides in the tap water and also the prevalent use of copper tube and fittings in the household plumbing which cause the presence of copper ions that initiate galvanic corrosion of the aluminium. A third disadvantage is pitting corrosion that can occur in an oxygen deprived environment when the appliance is out of operation for a long period of time.
The basic philosophy behind the present invention has been to provide an aluminium heat exchanger for CO2 based water heating that has an improved thermal performance with a higher corrosion resistance at a lower production cost than any competing products on the market today.
According to the present invention there is therefore provided a tube and shell heat exchanger, in particular a gas cooler/evaporator in water heat pump systems with refrigerants working at relatively high pressures such as C02, comprising an inner tube and outer shell, in which the inner tube is made of aluminium and is provided with a coating on its outer face in order to be sacrificial, protective or passive in relation to corrosion, and the outer shell consists of another polymer material.
The coating on the outer face of the inner tube may be a thin layer of polymer material, especially a Polyamide, preferably PAl 2 film, forming an impervious barrier between the water and the aluminium.
Alternatively, the coating on the outer face of the inner tube may be a sacrificial coating e.g. a zinc coating.
In a further alternative embodiment, the coating on the outer face of the inner tube may be a sol gel coating or a coating based on anodising treatment to passivate the surface.
It is preferred that the outer shell part is made of Polyethylene, preferably cross-linked Polyethylene material (a PEX-tube).
Preferably, the aluminium tube is an extruded aluminium profile with outer longitudinal fins.
It is also preferred that a number of internal enhancements are provided in the inner bore of the tube to avoid collapse of the inner tube during narrow bending radius applications.
The present invention will be described in more detail by way of example and with reference to the drawings, where: Fig. 1 is a perspective view of a CO2 gas cooler and residential tap water heat exchanger for heat pumps, Fig. 2 is a perspective view in larger scale and more detail of the outlet end part of the heat exchanger shown in Fig. 1.
The new heat exchanger according to the invention is a tube and shell heat exchanger and may be a bundle type or tube sling or serpentine type heat exchanger I as is shown in Fig. 1. Such a heat exchanger is in particular applicable for hot water heat pumps (gas cooler/evaporator) with CO2 as refrigerant and where the gas pressure is relatively high. Referring to Figs. 1 and 2, the heat exchanger includes an inner tube 2 and outer shell 3, The inner tube 2 with outer longitudinal fins 4 is preferably an extruded aluminium profile and is designed to hold the first heat exchanging medium, the gas, at high pressure (approximately 100 bar) whereas the annular space between the tube 2 and outer shell 3 is designed to hold the second heat exchanging medium, the water.
The heat exchanger further includes at its inlet and outlet ends 5, respectively 6 tube connecting means (1 connector) 7 with sealing means 8 to connect inlet and outlet gas connecting tubes 9 and inlet and outlet water connecting tubes 10 to the heat exchanger.
The corrosion problems related to the water side (shell side) are solved according to the invention by: -A) an outer shell part 3 consisting of a polymer, preferably Polyethylene and most preferably a cross-linked Polyethylene (PEX-tube) which as such is a well known material in today's plumbing, and -B) applying a coating on the outer face of the inner pipe (aluminium profile) 2 in order to obtain passivity, protect or be sacrificial.
The coating B) on the aluminium facing the water side (the outer face of the tube 2) may be: -a metallic coating e.g. zinc to be sacrificial, -a sol gel coating or a coating based on anodising treatment to passivate the surface, or -a thin layer of polymer material, preferably polyamide and most preferably a PAl 2 film forming an impervious barrier between the water and the aluminium.
The combination of polymer (plastic) material and metal tube with the flexible enhancement design by extrusion offers some overall improvements to the product in terms of reduced production cost and high corrosion resistance but it also offers high flexibility in terms of designing a customer specific thermal capacity (heat transfer) since it is just a matter of Increasing or decreasing the enhancement and/or length of the heat exchanger.
It is of utmost importance to maintain the heat transfer capacity of aluminium by using as thin as possible layer of polymer material on the outer face of the aluminium tube. The layer should, however, have sufficient corrosion protection and mechanical strength to withstand normal use and handling.
The invention as defined in the claims is not limited to the example shown in the figures and described above. Thus, in order to avoid collapse of the inner tube during narrow bending radius applications, a number of internal enhancements can be applied to the inner bore of the tube. This will strengthen the inner bore and prevent it from caving in at a bending zone.
Claims (8)
- Claims 1. A tube and shell heat exchanger (1), in particular a gas cooler/evaporator in water heat pump systems with refngerants working at relatively high pressures such as C02, comprising an inner tube (2) and outer shell (3), characterised in that the inner tube (2) is made of aluminium and is provided with a coating on its outer face in order to be sacrificial, protective or passive in relation to corrosion, and that the outer shell (3) consists of another polymer material.
- 2. A heat exchanger according to claim 1, characterised in that the coating on the outer face of the inner tube (2) is a thin layer of polymer material, especially a Polyamide, preferably PA12 film, forming an impervious barrier between the water and the aluminium.
- 3. A heat exchanger according to claim 1, characterised in that the coating on the outer face of the inner tube (2) is a sacrificial coating e.g. a zinc coating.
- 4. A heat exchanger according to claim 1, characterised in that the coating on the outer face of the inner tube (2) is a sol gel coating or a coating based on anodising treatment to passivate the surface.
- 5. A heat exchanger according to any one of the preceding claims, characterised in that the outer shell (3) is made of Polyethylene, preferably cross-linked Polyethylene material (a PEX-tube).
- 6. A heat exchanger according to any one of claims I to 4, characterised in that the aluminium tube is an extruded aluminium profile with outer longitudinal fins (4).
- 7. A heat exchanger according to any one of claims 1 to 4 and 6 characterised in that a number of internal enhancements are provided in the inner bore of the tube to avoid collapse of the inner tube during narrow bending radius applications.
- 8. A heat exchanger substantially as hereinbefore described and with reference to the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NO20080982 | 2008-02-25 | ||
| NO20081641 | 2008-04-02 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0903234D0 GB0903234D0 (en) | 2009-04-08 |
| GB2457599A true GB2457599A (en) | 2009-08-26 |
Family
ID=40565727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0903234A Withdrawn GB2457599A (en) | 2008-02-25 | 2009-02-25 | Shell and tube heat exchanger |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2457599A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220316823A1 (en) * | 2021-03-30 | 2022-10-06 | Rheem Manufacturing Company | Corrosion prevention for heat exchanger devices and pool heaters |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1536625A (en) * | 1976-05-10 | 1978-12-20 | Shiley Labor Inc | Heat exchanger apparatus and method for regulating the temperature of blood in an extracorporeal circuit |
| US4138288A (en) * | 1976-05-10 | 1979-02-06 | Shiley Scientific Incorporated | Method and apparatus for oxygenating and regulating the temperature of blood |
| US4138464A (en) * | 1976-05-10 | 1979-02-06 | Lewin John E | Blood oxygenator with integral heat exchanger |
| JPH09152299A (en) * | 1995-11-30 | 1997-06-10 | Sanyo Electric Co Ltd | Heat exchanger for external combustion engine using regenerating cycle |
| US20020157815A1 (en) * | 2001-04-27 | 2002-10-31 | Sutter Douglas E. | Heat exchange tubing |
| GB2418478A (en) * | 2004-09-24 | 2006-03-29 | Ti Group Automotive Sys Ltd | A heat exchanger |
-
2009
- 2009-02-25 GB GB0903234A patent/GB2457599A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1536625A (en) * | 1976-05-10 | 1978-12-20 | Shiley Labor Inc | Heat exchanger apparatus and method for regulating the temperature of blood in an extracorporeal circuit |
| US4138288A (en) * | 1976-05-10 | 1979-02-06 | Shiley Scientific Incorporated | Method and apparatus for oxygenating and regulating the temperature of blood |
| US4138464A (en) * | 1976-05-10 | 1979-02-06 | Lewin John E | Blood oxygenator with integral heat exchanger |
| JPH09152299A (en) * | 1995-11-30 | 1997-06-10 | Sanyo Electric Co Ltd | Heat exchanger for external combustion engine using regenerating cycle |
| US20020157815A1 (en) * | 2001-04-27 | 2002-10-31 | Sutter Douglas E. | Heat exchange tubing |
| GB2418478A (en) * | 2004-09-24 | 2006-03-29 | Ti Group Automotive Sys Ltd | A heat exchanger |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220316823A1 (en) * | 2021-03-30 | 2022-10-06 | Rheem Manufacturing Company | Corrosion prevention for heat exchanger devices and pool heaters |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0903234D0 (en) | 2009-04-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |