CA2499865C - Improved recuperator of flue gas heat - Google Patents
Improved recuperator of flue gas heat Download PDFInfo
- Publication number
- CA2499865C CA2499865C CA 2499865 CA2499865A CA2499865C CA 2499865 C CA2499865 C CA 2499865C CA 2499865 CA2499865 CA 2499865 CA 2499865 A CA2499865 A CA 2499865A CA 2499865 C CA2499865 C CA 2499865C
- Authority
- CA
- Canada
- Prior art keywords
- flue
- air
- metal
- furnace
- heat
- 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.)
- Expired - Fee Related
Links
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
- F28D7/10—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
- F28D7/106—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 consisting of two coaxial conduits or modules of two coaxial conduits
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J13/00—Fittings for chimneys or flues
- F23J13/02—Linings; Jackets; Casings
-
- 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
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D21/0001—Recuperative heat exchangers
- F28D21/0003—Recuperative heat exchangers the heat being recuperated from exhaust gases
- F28D21/0005—Recuperative heat exchangers the heat being recuperated from exhaust gases for domestic or space-heating systems
- F28D21/0008—Air heaters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2211/00—Flue gas duct systems
- F23J2211/10—Balanced flues (combining air supply and flue gas exhaust)
- F23J2211/101—Balanced flues (combining air supply and flue gas exhaust) with coaxial duct arrangement
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F2240/00—Spacing means
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Air Supply (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The present invention relates to flue-mounted power heat recuperators designed to transfer heat from flue gas through metal to air. In this invention a heat reflecting flexible sleeve encloses a metal flue of low emissivity, forming a "tube-within-a-tube" heat exchanger, and heat is reclaimed directly from the outside surface of the said flue by means of counterflow or parallel-flow forced air convection. The above arrangement provides air of higher temperature, and when combined with a central home-heating forced air furnace it increases temperature of supply air and enhances efficiency of the whole central home-heating system.
Description
IMPROVED RECUPERATOR OF FLUE GAS HEAT
This invention relates, in general, to the flue-mounted power heat recuperators designed to transfer flue gas heat through metal to air, and in particular, to the Recuperator of Flue Gas Heat which has been granted the Canadian Patent No.: 1 235 412 on April 19, 1988.
In view of the fact, that the said patented Recuperator utilizes radiant heat, there has been a commonly held opinion, that its best performance could only be attained, when it is mounted on a flue which yields the maximum thermal emittance.
In contrast with the aforementioned opinion, I have found, that the best performance could be achieved by extracting heat directly from the heat transfer surface of a flue, having a low thermal emissivity, by using counterflow or parallel-flow forced air convection.
This may be accomplished by replacing the existing flue with a flue of a low thermal emissivity, such as the one that is made of galvanized steel, and by forming a "tube-within-a-tube" heat exchanger of the flue itself by enclosing it with a sleeve of a larger diameter, held in concentrical position to the said flue by means of spacers, arranged in such a way that they do not restrain air flow through the resulting annulus into an outlet air duct connected to the sleeve.
In order to exploit fully radiant heat, as well as the heat transfer surface of the flue, including its elbows, the said sleeve may be constructed in whole or in part of a flexible tubing made of a heat reflecting material.
When such a device is equipped with a fan in its outlet air duct, the generated air flow reclaims heat from flue gas and conveys it, through the said air duct, into a desired room.
Alternatively, such a device may be used as an auxiliary heat exchanger to a forced air combustion central home-heating furnace in order to enhance efficiency of the whole heating system. This may be achieved by connecting its outlet air duct directly to a return air duct or plenum of the said furnace. Consequently, when the furnace blower is in operation, negative pressure in the return air duct conveys a certain portion of return air into the furnace via the said auxiliary heat exchanger.
This portion of return air reclaims flue gas heat and transfers it to the rest of the return air, increasing thus ultimately the temperature of supply air. A further advantage of such an arrangement is, that the reclaimed flue gas heat is distributed through the existing network of supply ducts without any additional fan, or increased intensity of forced air circulation.
In the drawings which illustrate embodiments of the invention, Figure 1 is a longitudinal section indicated by line 1-1 in Figure 2, illustrating the device in an arrangement designed for operation within circulation of heated air.
Figure 2 is a view, partly in section indicated by line 2-2 in Figure 1.
Figures 3 and 4 are cross sections indicated by the correspondingly numbered lines in Figure 1.
Figure 5 is a longitudinal section indicated by line 5-5 in Figure 6, illustrating the device in a modified arrangement designed for operation within circulation of heated air.
Figure 6 is a view indicated by line 6-6 in Figure 5.
Figure 7 is a cross section indicated by line 7-7 in Figure 5.
Figure 8 is a longitudinal section indicated by line 8-8 in Figure 9, illustrating the device in an arrangement designed for operation outside circulation of heated air.
Figure 9 is a view, partly in section indicated by line 9-9 in Figure 8.
Figures 10 and 11 are cross sections indicated by the correspondingly numbered lines in Figure 8.
Figure 12 illustrates an application of my invention in combination with a fan controlled by a thermostatic switch. The same also illustrates schematically my invention in an application outside circulation of heated air.
This invention relates, in general, to the flue-mounted power heat recuperators designed to transfer flue gas heat through metal to air, and in particular, to the Recuperator of Flue Gas Heat which has been granted the Canadian Patent No.: 1 235 412 on April 19, 1988.
In view of the fact, that the said patented Recuperator utilizes radiant heat, there has been a commonly held opinion, that its best performance could only be attained, when it is mounted on a flue which yields the maximum thermal emittance.
In contrast with the aforementioned opinion, I have found, that the best performance could be achieved by extracting heat directly from the heat transfer surface of a flue, having a low thermal emissivity, by using counterflow or parallel-flow forced air convection.
This may be accomplished by replacing the existing flue with a flue of a low thermal emissivity, such as the one that is made of galvanized steel, and by forming a "tube-within-a-tube" heat exchanger of the flue itself by enclosing it with a sleeve of a larger diameter, held in concentrical position to the said flue by means of spacers, arranged in such a way that they do not restrain air flow through the resulting annulus into an outlet air duct connected to the sleeve.
In order to exploit fully radiant heat, as well as the heat transfer surface of the flue, including its elbows, the said sleeve may be constructed in whole or in part of a flexible tubing made of a heat reflecting material.
When such a device is equipped with a fan in its outlet air duct, the generated air flow reclaims heat from flue gas and conveys it, through the said air duct, into a desired room.
Alternatively, such a device may be used as an auxiliary heat exchanger to a forced air combustion central home-heating furnace in order to enhance efficiency of the whole heating system. This may be achieved by connecting its outlet air duct directly to a return air duct or plenum of the said furnace. Consequently, when the furnace blower is in operation, negative pressure in the return air duct conveys a certain portion of return air into the furnace via the said auxiliary heat exchanger.
This portion of return air reclaims flue gas heat and transfers it to the rest of the return air, increasing thus ultimately the temperature of supply air. A further advantage of such an arrangement is, that the reclaimed flue gas heat is distributed through the existing network of supply ducts without any additional fan, or increased intensity of forced air circulation.
In the drawings which illustrate embodiments of the invention, Figure 1 is a longitudinal section indicated by line 1-1 in Figure 2, illustrating the device in an arrangement designed for operation within circulation of heated air.
Figure 2 is a view, partly in section indicated by line 2-2 in Figure 1.
Figures 3 and 4 are cross sections indicated by the correspondingly numbered lines in Figure 1.
Figure 5 is a longitudinal section indicated by line 5-5 in Figure 6, illustrating the device in a modified arrangement designed for operation within circulation of heated air.
Figure 6 is a view indicated by line 6-6 in Figure 5.
Figure 7 is a cross section indicated by line 7-7 in Figure 5.
Figure 8 is a longitudinal section indicated by line 8-8 in Figure 9, illustrating the device in an arrangement designed for operation outside circulation of heated air.
Figure 9 is a view, partly in section indicated by line 9-9 in Figure 8.
Figures 10 and 11 are cross sections indicated by the correspondingly numbered lines in Figure 8.
Figure 12 illustrates an application of my invention in combination with a fan controlled by a thermostatic switch. The same also illustrates schematically my invention in an application outside circulation of heated air.
Figure 13 illustrates an application of my invention in combination with a fan, having its operation synchronized with operation of a flue gas generating power burner. The same also illustrates schematically my invention in an application within circulation of heated air.
Figure 14 illustrates an application of my invention in combination with a forced air combustion furnace operating outside circulation of heated air.
Figure 15 illustrates an application of my invention combination with a forced air combustion furnace operating within circulation of heated air.
Referring to the drawings illustrating the device, 1 indicates a split sheet-metal cylinder with a heat reflecting finish, equipped with an air duct 2, spacers 3, and bolted joint 4, that facilitates installation and fastening the said cylinder to a flue 5, which is made of galvanized steel. The sheet-metal cylinder is extended by a heat reflecting flexible duct 6 of the same diameter, held in concentrical position to the flue by means of extension coil springs 7, wrapped around the flue where necessary. The other end of the flexible duct is either held in a desired position by a sheet-metal ring 8, provided with spacers 3, or is connected to another sheet-metal cylinder 1, equipped with an air duct, spacers and a bolted joint, as illustrated in Figures 8-11. In any arrangement, the open end of the _4-cylinder, which is not connected to the flexible duct 6, is blocked by a sheet-metal annulus 9.
Referring to the drawings illustrating applications of the device in combination with a fan, 10 indicates a motor-driven fan generating air flow through a device 11, which represents an apparatus designed to operate outside circulation of heated air, as described in Figures 8-11, yr through a device 12, which represents an apparatus designed to operate within circulation of heated air, as described in Figures 1-4 or 5-7. This air flow reclaims flue gas heat and conveys it into a desired room.
Operation of the said motor-driven fan may be controlled by a normally open thermostatic switch 13, which closes the circuit only for the periods when the temperature of flue gas is in excess of a certain preset limit, or it may be synchronized with a flue gas generating power burner 14, which, as a component of a heater or furnace, is controlled by its own thermostat 15.
Referring to the drawings illustrating application of the device in combination with a forced air combustion central home-heating furnace, 16 indicates a sheet-metal baffle restricting the regular intake of return air into a furnace proportionally with added intake through the device 11 or 12 communicating directly with a return air duct or plenum 17 of the said furnace. Consequently, when the furnace blower 18 is in operation, the generated negative pressure in the return air plenum conveys a certain portion of return air into the furnace via the device il or 12. This portion of return air reclaims flue gas heat and transfers it to the rest of return air, increasing thus ultimately the temperature of supply air.
_6_
Figure 14 illustrates an application of my invention in combination with a forced air combustion furnace operating outside circulation of heated air.
Figure 15 illustrates an application of my invention combination with a forced air combustion furnace operating within circulation of heated air.
Referring to the drawings illustrating the device, 1 indicates a split sheet-metal cylinder with a heat reflecting finish, equipped with an air duct 2, spacers 3, and bolted joint 4, that facilitates installation and fastening the said cylinder to a flue 5, which is made of galvanized steel. The sheet-metal cylinder is extended by a heat reflecting flexible duct 6 of the same diameter, held in concentrical position to the flue by means of extension coil springs 7, wrapped around the flue where necessary. The other end of the flexible duct is either held in a desired position by a sheet-metal ring 8, provided with spacers 3, or is connected to another sheet-metal cylinder 1, equipped with an air duct, spacers and a bolted joint, as illustrated in Figures 8-11. In any arrangement, the open end of the _4-cylinder, which is not connected to the flexible duct 6, is blocked by a sheet-metal annulus 9.
Referring to the drawings illustrating applications of the device in combination with a fan, 10 indicates a motor-driven fan generating air flow through a device 11, which represents an apparatus designed to operate outside circulation of heated air, as described in Figures 8-11, yr through a device 12, which represents an apparatus designed to operate within circulation of heated air, as described in Figures 1-4 or 5-7. This air flow reclaims flue gas heat and conveys it into a desired room.
Operation of the said motor-driven fan may be controlled by a normally open thermostatic switch 13, which closes the circuit only for the periods when the temperature of flue gas is in excess of a certain preset limit, or it may be synchronized with a flue gas generating power burner 14, which, as a component of a heater or furnace, is controlled by its own thermostat 15.
Referring to the drawings illustrating application of the device in combination with a forced air combustion central home-heating furnace, 16 indicates a sheet-metal baffle restricting the regular intake of return air into a furnace proportionally with added intake through the device 11 or 12 communicating directly with a return air duct or plenum 17 of the said furnace. Consequently, when the furnace blower 18 is in operation, the generated negative pressure in the return air plenum conveys a certain portion of return air into the furnace via the device il or 12. This portion of return air reclaims flue gas heat and transfers it to the rest of return air, increasing thus ultimately the temperature of supply air.
_6_
Claims (2)
1. A system for transferring heat from flue gas through metal to air to achieve maximum surface temperature and bring a higher rate of surface to air convective heat transfer, comprising:
a metal flue for venting flue gas from a combustion heater, stove or furnace, wherein said metal flue has outside surface of low emmissivity;
spacing means arranged on periphery of said metal flue wherein said spacing means have no areal contact with said metal flue;
a flexible sleeve having a wall made of a heat reflecting material and inside diameter sized to fit over said spacing means wherein said flexible sleeve is held in coaxial position to said metal flue by said spacing means thereby forming an annular passageway along said metal flue to allow air flow along and in contact with outside surface of said metal flue;
an outlet air duct fluidly connected to said flexible sleeve; and a fan or other means generating negative pressure in the said outlet air duct.
a metal flue for venting flue gas from a combustion heater, stove or furnace, wherein said metal flue has outside surface of low emmissivity;
spacing means arranged on periphery of said metal flue wherein said spacing means have no areal contact with said metal flue;
a flexible sleeve having a wall made of a heat reflecting material and inside diameter sized to fit over said spacing means wherein said flexible sleeve is held in coaxial position to said metal flue by said spacing means thereby forming an annular passageway along said metal flue to allow air flow along and in contact with outside surface of said metal flue;
an outlet air duct fluidly connected to said flexible sleeve; and a fan or other means generating negative pressure in the said outlet air duct.
2. The system of claim 1 wherein said furnace is a central home-heating forced air furnace and said outlet air duct is fluidly connected to a return air duct or plenum of said central home-heating forced air furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2499865 CA2499865C (en) | 2005-03-24 | 2005-03-24 | Improved recuperator of flue gas heat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2499865 CA2499865C (en) | 2005-03-24 | 2005-03-24 | Improved recuperator of flue gas heat |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2499865A1 CA2499865A1 (en) | 2006-09-24 |
| CA2499865C true CA2499865C (en) | 2012-06-12 |
Family
ID=37055021
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2499865 Expired - Fee Related CA2499865C (en) | 2005-03-24 | 2005-03-24 | Improved recuperator of flue gas heat |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2499865C (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101608996B1 (en) * | 2010-01-11 | 2016-04-05 | 엘지전자 주식회사 | Heat exchanger |
| CN102954484B (en) * | 2011-08-31 | 2015-07-29 | 宝钢工业炉工程技术有限公司 | Compact thermal stress compensation formula radiant tube heat exchange device |
| FR2982011A1 (en) * | 2011-10-28 | 2013-05-03 | Fadis | Heat recovery device for stove i.e. wood stove, utilized in heating installation of dwelling, has deflector arranged in free space to force air flow to partially wrap around pipe of stove, where air flow circulates in free space |
| FR3010788B1 (en) * | 2013-09-18 | 2015-10-16 | Olythe | MEASURING TANK FOR MEASURING APPARATUS SPECTROMETRY |
| SE540114C2 (en) * | 2014-03-27 | 2018-04-03 | Skorstensbolaget I Stockholm Ab | Tubular countercurrent air heat exchanger including spacers between the tubes |
-
2005
- 2005-03-24 CA CA 2499865 patent/CA2499865C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2499865A1 (en) | 2006-09-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20200831 |