GB2080509A - Heat Exchanger and Method of Manufacture Thereof - Google Patents
Heat Exchanger and Method of Manufacture Thereof Download PDFInfo
- Publication number
- GB2080509A GB2080509A GB8121506A GB8121506A GB2080509A GB 2080509 A GB2080509 A GB 2080509A GB 8121506 A GB8121506 A GB 8121506A GB 8121506 A GB8121506 A GB 8121506A GB 2080509 A GB2080509 A GB 2080509A
- Authority
- GB
- United Kingdom
- Prior art keywords
- outer tube
- heat exchanger
- tubes
- tube
- liquid
- 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- Withdrawn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
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 238000000034 method Methods 0.000 title claims description 11
- 239000007788 liquid Substances 0.000 claims abstract description 15
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 8
- 239000010959 steel Substances 0.000 claims abstract description 8
- 238000005452 bending Methods 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000010257 thawing Methods 0.000 claims abstract description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 125000006850 spacer group Chemical group 0.000 claims description 5
- 239000000110 cooling liquid Substances 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910000975 Carbon steel Inorganic materials 0.000 claims 2
- 239000010962 carbon steel Substances 0.000 claims 2
- 239000012267 brine Substances 0.000 abstract description 3
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 abstract description 3
- 239000002826 coolant Substances 0.000 abstract 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- 239000003507 refrigerant Substances 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910001369 Brass Inorganic materials 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000010951 brass Substances 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- JHWIEAWILPSRMU-UHFFFAOYSA-N 2-methyl-3-pyrimidin-4-ylpropanoic acid Chemical compound OC(=O)C(C)CC1=CC=NC=N1 JHWIEAWILPSRMU-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VOPWNXZWBYDODV-UHFFFAOYSA-N Chlorodifluoromethane Chemical compound FC(F)Cl VOPWNXZWBYDODV-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 229910000743 fusible alloy Inorganic materials 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000004804 winding Methods 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
- F28D7/02—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 helically coiled
- F28D7/022—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 helically coiled the conduits of two or more media in heat-exchange relationship being helically coiled, the coils having a cylindrical configuration
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
The heat exchanger comprises an outer tube (11) containing at least one inner tube (12) therein. In order to improve the efficiency but occupy minimal space, the diameter of the outer tube (11) is small compared with its length; the tubes are bent into a spiral or helix and are formed of steel. The heat exchanger is formed by filling the outer tube (11) with a liquid (e.g. water), passing a coolant (e.g. cooled brine) through the inner tubes so as to freeze the liquid, bending the tube assembly (10) to form the desired shape and then thawing the frozen liquid in the outer tube (11). <IMAGE>
Description
SPECIFICATION
Heat Exchanger and Method of Manufacture
Thereof
This invention relates to a heat exchanger for a heat pump and comprises an outer tube containing at least one inner tube.
In heat pumps, use is normally made of clustered-tube heat exchangers consisting of a short tubular cylinder in which a plurality of inner tubes are arranged. The ends of the inner tubes projecting from the tubular cylinder are bundled together to reduce their diameter and are connected to ducts connecting them with a flow circuit for a first working medium. However, such an assembly has a complicated manufacturing procedure. Furthermore, these known heat exchangers must be designed, owing to their relatively large diameter, with extraordinarily thick walls to withstand the high pressures encountered during use. Finally, such a heat exchanger requires a substantial amount of working medium to fill it.
These factors negatively affect, in particular, the weight and manufacturing cost of heat pumps fitted with such heat exchangers. This makes the use of such heat exchangers very uneconomical for heating single or multiplefamily homes, particularly in view of the fact that at the present state of the art the use of heat pumps will not save more than 45% of the primary energy expended.
For heat pumps, use has been made to date of the principle of compressor-operated coolers.
With such heat pumps, which normally use fluorhydrocarbons, such as frigen, as a refrigerant, the heat exchangers are made of copper or brass.
The principle of sorption coolers can be used also for heat pumps, however. In these cases, use is made of ammonia as a refrigerant. However, known heat exchangers are ill-suited for this, since ammonia attacks copper and brass.
An object of the present invention is to provide a heat exchanger for use in heat pumps of any type and which satisfies the requirements imposed on heat pumps when used for heating
homes, while still maintaining a high degree of efficiency.
The invention provides a heat exchanger for a
heat pump comprising an outer tube containing at
least one inner tube therein, wherein the diameter
of the outer tube is small compared with its
length, the tubes being bent into a spiral, screw or other bent shape and being formed of steel.
Such a heat exchanger while having an
improved efficiency, also has an appreciably
smaller volume than conventional heat
exchangers made of steel. Because of the
considerably smaller diameter of the outer tube, the heat exchanger of the present invention can
use substantially thinner walls, making for
relatively little mass and, thus, moderate weight
also when used in the higher pressure ranges
associated with a heat pump. Manufacture, too, is
simplified in that on average a much smaller number of inner tubes than seven can be used.
The ends of the inner tubes can be connected much more simply, or even directly, to a manifold tube.
Such a heat exchanger may be used in a heat
pump in which heat is transferred from one medium to another, e.g. in a condenser, evaporator, temperature changer, absorber, etc.
This universal use makes for economical, costeffective mass production of standardized heat exchangers. Since such heat exchangers can be
used for both compressor-type and absorptiontype heat pumps with their more aggressive wong
media, it will become apparent that
manufacturing costs can be reduced still further as a result of larger production quantities.
These advantages all operate to reduce the overall weight and price of heat pumps, which makes fitting heat pumps in home heating systems more economical, especially considering that a heat pump is provided with several heat exchangers.
The heat exchangers of the present invention affords another advantage in that a relatively simple modification of its basic geometry will adapt it to meet the requirements of various types of heat exchangers. It will also be possible to reduce the number of inner tubes and use finned inner tubes instead.
The small container volume and the small mass give, in conjunction with the forced circulation of the media, rapid response to load changes, and they also give a high degree of heat transfer even at low volume flow, making for high efficiency even with small differences in temperatures. This again helps expand the scope of applications for the heat exchanger of the present invention.
For heat exchanger parts wetted by ammonia or aqueous ammonia solutions, use is preferably made of carbon or chrome nickel steels employing sodium dichromate (Na2 Cr2 07) as an inhibitor.
The present invention also provides a method of manufacturing a heat exchanger as described, and comprises inserting at least one inner tube cut to length into an outer tube so as to be spaced therefrom, filling the outer tube with liquid, passing a cooling liquid through the inner tube or tubes, so as to freeze the liquid in the outer tube, bending the tube assembly around a mandrel for form the desired shape, and thawing the frozen liquid in the outer tube.
It is a known practice to fill tubes with a supporting substance to prevent their being crushed when bent. Conventionally, the tubes are filled with either sand or low-melting alloys.
These temporarily used substances provide a disadvantage, however, in that they are difficult to remove after bending. And when alloys are used, the melting step used when filling must be repeated when emptying the tubes.
The method of the present invention requires the supply of external energy only once, when the cooling liquid, e.g. brine, is pumped into the inner tubes, while the frozen liquid, e.g. ice, in the outer tube will thaw at room temperature without further assistance. Another consideration is that the water, when used temporarily, and the brine can be removed from the tubes easily and completely. The tubes are preferably flushed afterwards with a dehydrating fluid.
It has also been shown that the ice will simultaneously support and maintain the spacing of the inner tubes, which eliminates the need for additionally filling the inner tubes with a supporting medium.
In order to maintain accurate spacing of the inner tubes with each other and with the outer tube, the inner tubes are advantageously fitted with spacers, such as resilient rings, before they are inserted into the shroud tube.
An embodiment of the present invention is shown schematically in the accompanying drawing, in which:
Fig. 1 is an elevational view of a heat exchanger according to the invention, and
Fig. 2 is a plan view of the heat exchanger of
Fig. 1.
The coaxial heat exchanger shown in Fig. 1
consists of a helically bent heat-exchanger tube
10 comprising an outer tube 11 and seven inner tubes 12 arranged therein. The inner tubes 12 are spaced apart at fixed distances from each other and from the shroud tube wall by means of spacers 13 so that, in use, the inner tubes 1 2 will be uniformly wetted by medium flowing through the outer tube 10, thus providing optimum heat transfer between the medium inside the inner tubes 1 2 and the medium outside them. The heat-exchanging media ducted inside the heat exchanger tube 10 can be made to flow in the same or, preferably, in opposite directions.
As can be seen more clearly from Fig. 2, each end of the heat exchanger tube 10 is provided with a T-shaped connector 14. The inner tubes 12 are welded to one end 1 5 of the T-shaped
Connector. This connects to a ducting system (not shown) which carries the working medium used in the inner tubes 12.
The T-shaped connector 14 has a lateral connection 1 6 for the working medium flowing in the outer tube 11 outside the inner tubes 12.
Manufacture of the above-described heat exchanger comprises a few very simple steps. The originally straight tubes 11 and 12 are first cut to the right length. The inner tubes 1 2 are spaced apart by the spacers 13 3 and then inserted into the outer tube 1 The T-shaped connectors 1 4 are then welded in place and the outer tube 11 is filled with water or some other liquid via the connection 1 6.
In order to freeze the liquid contained in the outer tube 11, a refrigerant is pumped into the inner tubes 12. Owing to the steel used, more particularly mild steel, the thermal expansion of the water caused by freezing will not adversely affect the heat-exchanger tube 1 0.
The tube, now filled with ice as a temporary agent, is then suitably wound or bent around a mandrel. In order to achieve a minimum overall size, the windings are urged closely together side by side. This simultaneously reduces to a certain extent the outer surface area the heat exchanger presents to the atmosphere. The present method has shown that the tube will not appreciably expand elastically after the bending tools have been frozen. This enables the end product to be manufactured with precision and reproducibility for closely toleranced mass production.
After the bending operation, the ice will melt automatically at room temperature, so that the temporary working medium and the refrigerant pumped into the inner tubes 12 can be drained from the tubes. The tubes 11 and 12 can then be flushed with another medium if so required.
Claims (8)
1. A heat exchanger for a heat pump comprising an outer tube containing at least one inner tube therein, wherein the diameter of the outer tube is small compared with its length, the tubes being bent into a spiral, screw or other bent shape and being formed of steel.
2. A heat exchanger as claimed in claim 1, wherein the tubes are formed of carbon steel.
3. A heat exchanger as claimed in claim 1, wherein the tubes are formed of chrome nickel steel.
4. A heat exchanger substantially as herein described with reference to the accompanying drawing.
5. A method of manufacturing a heat exchanger as claimed in any one of the preceding claims, comprising inserting at least one inner tube cut to length into an outer tube so as to be spaced therefrom, filling the outer tube with liquid, passing a cooling liquid through the inner tube or tubes, so as to freeze the liquid in the outer tube, bending the tube assembly around a
mandrel to form the desired shape, and thawing the frozen liquid in the outer tube.
6. A method as claimed in claim 5, wherein the
outer tube is filled with water.
7. A heat exchanger for a heat pump manufactured by the method as claimed in any one of the preceding claims.
7. A method as claimed in claim 5 or 6,
wherein the inner tube or tubes are provided with
spacers before they are inserted into the outer
tube.
8. A method of manufacturing a heat
exchanger as claimed in claim 1 substantially as
herein described with reference to the
accompanying drawing.
New Claims or Amendments to Claims filed on 21st October 1981.
Superseded Claims 1 to
8.
New or Amended Claims:
1. A method of manufacturing a heat
exchanger for a heat pump comprising inserting
at least one inner tube cut to length into an outer
tube so as to be spaced therefrom, filling the
outer tube with liquid, passing a cooling liquid
through the inner tube or tubes, so as to freeze
the liquid in the outer tube, bending the tube assembly around a mandrel to form the desired shape, and thawing the frozen liquid in the outer tube.
2. A method as claimed in claim 1, wherein the outer tube is filled with water.
3. A method as claimed in claim 1 or 2, wherein the inner tube or tubes are provided with spacers before they are inserted into the outer tube.
4. A method as claimed in any one of claims 1 to 3, wherein the tubes are formed of carbon steel.
5. A method as claimed in any one of claims 1 to 3, wherein the tubes are formed of chrome nickel steel.
6. A method of manufacturing a heat exchanger for a heat pump substantially as herein described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19803027070 DE3027070A1 (en) | 1980-07-17 | 1980-07-17 | COAXIAL HEAT EXCHANGER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2080509A true GB2080509A (en) | 1982-02-03 |
Family
ID=6107412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8121506A Withdrawn GB2080509A (en) | 1980-07-17 | 1981-07-13 | Heat Exchanger and Method of Manufacture Thereof |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE3027070A1 (en) |
| GB (1) | GB2080509A (en) |
| NL (1) | NL8103369A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989007022A1 (en) * | 1988-02-01 | 1989-08-10 | Shipco A/S | Method for the protection of a coiled tube heat exchanger |
| GB2251678A (en) * | 1990-11-28 | 1992-07-15 | Shell Int Research | Heat exchange apparatus |
| CN100504273C (en) * | 2006-04-30 | 2009-06-24 | 韩军 | Manufacturing method of spiral casing heat exchanger |
| ITUD20090143A1 (en) * | 2009-08-07 | 2011-02-08 | F D E S R L | HEAT EXCHANGER DEVICE FOR THERMAL CONDITIONING SYSTEMS |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3403970A1 (en) * | 1984-02-04 | 1985-11-21 | Helmut 2420 Eutin Krueger-Beuster | Heat exchanger |
| DE3408626A1 (en) * | 1984-03-09 | 1985-09-12 | Wieland-Werke Ag, 7900 Ulm | Wound heat exchanger, in particular for heat pumps or refrigerating plants |
| DE102011050643B4 (en) * | 2011-05-26 | 2013-04-04 | Willi Bihler | Combined photovoltaic and solar thermal system |
| DE102022003363A1 (en) | 2022-09-13 | 2024-03-14 | Pitt Fischer | Balcony'' - local heating plant in a modular device system, for free heat generation using solar energy. |
| DE202023000405U1 (en) | 2022-09-13 | 2023-04-04 | Pitt Fischer | Balcony - local heating plant in the modular device system, for free generation of heat from solar energy |
-
1980
- 1980-07-17 DE DE19803027070 patent/DE3027070A1/en not_active Ceased
-
1981
- 1981-07-13 GB GB8121506A patent/GB2080509A/en not_active Withdrawn
- 1981-07-15 NL NL8103369A patent/NL8103369A/en not_active Application Discontinuation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1989007022A1 (en) * | 1988-02-01 | 1989-08-10 | Shipco A/S | Method for the protection of a coiled tube heat exchanger |
| GB2251678A (en) * | 1990-11-28 | 1992-07-15 | Shell Int Research | Heat exchange apparatus |
| CN100504273C (en) * | 2006-04-30 | 2009-06-24 | 韩军 | Manufacturing method of spiral casing heat exchanger |
| ITUD20090143A1 (en) * | 2009-08-07 | 2011-02-08 | F D E S R L | HEAT EXCHANGER DEVICE FOR THERMAL CONDITIONING SYSTEMS |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3027070A1 (en) | 1982-02-18 |
| NL8103369A (en) | 1982-02-16 |
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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) |