CN212692166U - Vertical falling film generator for gas air source absorption heat pump system - Google Patents

Vertical falling film generator for gas air source absorption heat pump system Download PDF

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Publication number
CN212692166U
CN212692166U CN202021852556.0U CN202021852556U CN212692166U CN 212692166 U CN212692166 U CN 212692166U CN 202021852556 U CN202021852556 U CN 202021852556U CN 212692166 U CN212692166 U CN 212692166U
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heat exchange
heat
generator
heat transfer
exchange corrugated
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由世俊
吴璋翔
张欢
王雅然
叶天震
郑雪晶
郑万冬
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Tianjin University
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Tianjin University
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A30/00—Adapting or protecting infrastructure or their operation
    • Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/62—Absorption based systems

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Abstract

The utility model discloses a vertical falling film generator for a gas air source absorption heat pump system, which comprises a burner and a generator shell, wherein a discharge pipeline of the burner vertically penetrates into the generator shell in sequence, a liquid distributor is arranged at the top in the generator shell, a solution tank is arranged at the bottom, and a flue gas discharge outlet is arranged in the middle of the side wall; the liquid distributor is provided with a dilute solution inlet and a steam outlet, a plurality of heat exchange corrugated pipes are arranged between the liquid distributor and the solution tank, the top ends of the heat exchange corrugated pipes are communicated with the liquid distributor, and the bottom ends of the heat exchange corrugated pipes are communicated with the solution tank; a conical tube plug-in is coaxially arranged in each heat exchange corrugated tube, the top position of the conical tube plug-in is higher than that of the heat exchange corrugated tube, and a gap is reserved between the tube wall of the heat exchange corrugated tube and the conical tube plug-in. The utility model saves space; the natural gas is used as a heat source, so that stepless regulation can be realized; the corrugated pipe is adopted for heat exchange, so that the heat transfer efficiency is improved; the adoption of the conical insert film distributor ensures the uniformity of the liquid film.

Description

Vertical falling film generator for gas air source absorption heat pump system
Technical Field
The utility model relates to an air source heat pump system in energy utilization and environmental protection field especially relates to a vertical falling liquid film generator that is used for gas air source absorption heat pump system.
Background
In recent years, how to promote clean heating in northern areas, ensure that people are warm and overwinter, and reduce haze and pollution becomes a hot problem. Air source heat pump technology, which uses an air source as a heat source to extract heat, is a promising technology. The air source absorption heat pump has the characteristics of stable performance, abundant heat sources, convenience in installation and use and the like, and is widely applied to the fields of heating and air conditioning. The technology can convert low-grade energy into high-grade energy by utilizing a part of electric energy or heat energy, is energy-saving and efficient, and is safe and environment-friendly. The adoption of air source absorption heat pumps instead of coal is one of the main modes of clean heating in rural areas and has been greatly supported by the nation and government. However, the air source absorption heat pump has a low coefficient of performance, and how to improve the efficiency of the system is a current hot problem, especially for the research on the core component generator. Nowadays, the commonly used generators are the immersion generator and the spray generator. The liquid hydrostatic column pressure of the immersion generator can influence the generation effect, and the spray generator has the characteristics of small spray amount, insufficient utilization of heat transfer area and difficulty in complete wetting although the spray generator has no influence of the hydrostatic column and has good heat transfer and mass transfer performance. In addition to this, there are vertical falling film and horizontal falling film generators. Compared with a horizontal falling film generator, the vertical falling film generator has the characteristics of small occupied area, space saving, better formation of countercurrent heat exchange, more uniform liquid distribution, better wetting rate, higher temperature heat output and the like.
SUMMERY OF THE UTILITY MODEL
To above-mentioned prior art, in order to reduce equipment area, practice thrift the space, strengthen the heat transfer, the utility model provides a vertical falling liquid film generator for gas air source absorption heat pump system to the natural gas can realize electrodeless regulation as the heat source, directly heats for the cycle medium, adopts the bellows heat exchange tube, has improved heat transfer efficiency. The smoke discharge outlet is arranged, smoke can be discharged to the system for utilization in a centralized mode, and a conical insert film distributor is adopted to guarantee that a liquid film is uniform.
In order to solve the technical problem, the utility model provides a vertical falling film generator for gas air source absorption heat pump system, including combustor and generator housing, the emission pipeline of combustor vertically penetrates the generator housing in proper order, the top in the generator housing is equipped with the liquid distributor, the liquid distributor is equipped with dilute solution import and steam outlet, the lateral wall middle part of generator housing is equipped with the flue gas discharge outlet, the bottom in the generator housing is equipped with the solution tank, the bottom of solution tank is equipped with the concentrated solution export; a plurality of heat exchange corrugated pipes are arranged between the liquid distributor and the solution tank, the top ends of the heat exchange corrugated pipes are communicated with the liquid distributor, the bottom ends of the heat exchange corrugated pipes are communicated with the solution tank, and the bottom ends of the heat exchange corrugated pipes are higher than the liquid level of the concentrated solution in the solution tank; a conical barrel plug-in is coaxially arranged in each heat exchange corrugated pipe, the top position of the conical barrel plug-in is higher than that of the heat exchange corrugated pipe, and a gap is reserved between the pipe wall of the heat exchange corrugated pipe and the conical barrel plug-in.
Further, in the vertical falling film generator of the present invention, the burner feeds premixed air and natural gas into the generator housing as a driving heat source to release heat to the solution; the dilute solution from the system absorber is pumped into a liquid distributor from a dilute solution inlet through a solution pump, and when the liquid level of the dilute solution in the liquid distributor is over the top of the heat exchange corrugated pipe, the dilute solution forms a uniform liquid film along the pipe wall of the heat exchange corrugated pipe under the guide action of the conical barrel plug; absorbing heat from the burner in the downward flowing process of the dilute solution, evaporating low-boiling-point water in the dilute solution into steam, enabling the steam to flow upwards along the heat exchange corrugated pipe, and entering a condenser from a steam outlet of a liquid distributor; the concentration of the dilute solution gradually rises and is concentrated solution when reaching the solution tank at the bottom, and the concentrated solution is discharged from a concentrated solution outlet of the solution tank and enters the absorber.
The area of the heat exchange corrugated pipe in the utility model is A; if the whole heat transfer process of the vertical falling film generator is a composite heat transfer mode of convection heat transfer and radiation heat transfer, the qualitative temperature tmComprises the following steps:
Figure BDA0002657507350000021
in the formula (1), twIs the temperature, t, occurring in the heat exchange corrugated pipefIs the air temperature at combustion; according to the qualitative temperature tmPhysical parameters of air such as kinematic viscosity upsilon, thermal conductivity coefficient upsilon, prandtl number Pr and volume expansion coefficient alpha can be found in a dry air thermal physical property table of heat transfer science, and the gradaff number Gr is as follows:
Figure BDA0002657507350000022
in the formula (2), g is the gravity acceleration, and l is the length of the heat exchange corrugated pipe; calculating the product of the Grafaff number and the Gr Prandtl number Pr; according to the formula of the vertical wall rule, the wall temperature is constant, and the Nu is as follows:
Nu＝0.1×(GrPr)1/3 (3)
the convective heat transfer coefficient is hc：
Figure BDA0002657507350000023
Radiative heat transfer coefficient hrComprises the following steps:
Figure BDA0002657507350000024
in the formula (5), ε represents an emissivity value, CbThe radiation coefficient is, the heat transfer coefficient of the composite heat exchange outside the heat exchange corrugated pipe is as follows:
h＝hr+hc (6)
the area a of the heat exchange bellows is:
Figure BDA0002657507350000025
in the formula (7), Q is the heat generated by the fuel gas, and Delta T is the heat exchange temperature difference.
And designing the number and the diameter of the heat exchange corrugated pipes in the vertical falling film generator according to the length l and the area A of the heat exchange corrugated pipes.
Compared with the prior art, the beneficial effects of the utility model are that:
vertical falling liquid film generator, reduced equipment area, practiced thrift the space, strengthened the heat transfer. Natural gas is used as a driving heat source and directly exchanges heat with the circulating working medium, so that the environmental pollution is reduced, and the heat exchange efficiency is increased. The heat exchange tube adopts a corrugated tube to strengthen heat transfer and increase the turbulence degree. The smoke exhaust outlet is beneficial to the recovery of smoke waste heat by the system, and the film distributor in the form of the conical cylinder plug-in can ensure that the liquid film uniformly flows downwards. Meanwhile, a calculation model of the heat transfer process of the generator is provided, and reference is provided for engineering design and experiments.
Drawings
Fig. 1 is a schematic structural diagram of a vertical falling film generator according to the present invention.
Fig. 2 is a schematic structural diagram of a liquid distributor 4 in the vertical falling film generator of the present invention;
fig. 3 is a schematic structural diagram of the solution tank 8 in the vertical falling film generator of the present invention.
In the figure:
1-burner 2-steam outlet 3-dilute solution inlet 4-liquid distributor
5-generator shell 6-heat exchange corrugated pipe 7-flue gas discharge outlet 8-solution tank
9-concentrated solution outlet 10-conical barrel plug-in 11-dilute solution flow direction 12-dilute solution
13-steam flow direction 14-concentrated solution 15-baffle
Detailed Description
The present invention will be further described with reference to the following drawings and specific examples, but the following examples are by no means limiting the present invention.
As shown in fig. 1, the utility model provides a pair of vertical falling liquid film generator for gas air source absorption heat pump system, including combustor 1 (constitute by fan and combustor), liquid distributor 4, toper section of thick bamboo plug-in components 10, heat exchange tube, solution tank 6 and generator housing 5, generator housing 5 is stainless steel material, the vertical penetrating in proper order of emission pipeline of combustor 1 generator housing 5, liquid distributor 4 arranges at the top of generator housing 5, and it includes dilute solution import 3 and steam outlet 2, and the middle part of generator housing 5 is equipped with flue gas discharge outlet 7, solution tank 8 is located the bottom of generator housing 5, there is concentrated solution export 9 solution 8 lower part in solution tank 8. The liquid distributor 4 and the generator shell 5 and the solution tank 8 and the generator shell 5 are isolated by baffles 15. The utility model provides a heat exchange tube is heat transfer bellows 6, adopts the bellows can strengthen heat transfer, makes the torrent degree increase, and its tube bank length and quantity are confirmed according to system load size. The upper part of the heat exchange corrugated pipe 6 is communicated with the liquid distributor 4 and extends out, the lower part of the heat exchange corrugated pipe 6 is connected to the solution tank 8, and the position of the bottom end of the heat exchange corrugated pipe 6 is higher than the liquid level position of the concentrated solution 14 in the solution tank 8, as shown in fig. 3; this generator shell 5 adopts seamless welding, and the coaxial toper section of thick bamboo plug-in components 10 that is equipped with in every heat transfer bellows 6, the top position of toper section of thick bamboo plug-in components 10 is than the place the top position of heat transfer bellows 6 is high, the pipe wall of heat transfer bellows 6 with toper section of thick bamboo plug-in components 10 leaves the gap, adopts the film distributor of toper section of thick bamboo plug-in components 10 form promptly for falling liquid film entrance to guarantee that the liquid film is even.
The working process of the vertical falling film generator of the present invention is described by taking a lithium bromide absorption heat pump as an example. In the absorber, the high-concentration lithium bromide solution absorbs the water vapor and becomes a low-concentration dilute solution 12. The dilute solution 12 from the system absorber is pumped into the liquid distributor 4 of the generator from the dilute solution inlet 3 through the solution pump, the liquid level in the liquid distributor 4 gradually rises, when the liquid level of the dilute solution 12 in the liquid distributor 4 is over the pipe orifice of the heat exchange corrugated pipe 6, under the flow guiding effect of the conical cylinder plug-in piece (10), the dilute solution 12 flows into the heat exchange corrugated pipe 6 through the conical cylinder plug-in piece 10 (a gap between the dilute solution and the heat exchange corrugated pipe 6, namely, a film distributor), and the film distributor of the conical cylinder plug-in piece 10 enables the dilute solution 12 to uniformly flow downwards along the inner wall surface of the heat exchange corrugated pipe 6, so that a uniform liquid film is formed. In the flowing process of the dilute solution 12 in the pipe (the flowing direction of the dilute solution is shown by an arrow 11 in fig. 2), the combustor 1 outside the pipe burns the mixed natural gas and air, and sends the mixed natural gas and air into the generator shell 5 through a vertical downward discharge pipeline to be used as a driving heat source to release heat to the solution, and carries out convective heat transfer and radiative heat transfer with the heat transfer corrugated pipe 6 to input heat to the heat transfer corrugated pipe 6. After the lithium bromide dilute solution in the heat exchange corrugated pipe 6 absorbs the heat from the burner 1, the low boiling point water in the dilute solution 12 is evaporated by heat, changed into steam from the dilute solution 12 and flows upwards along the heat exchange corrugated pipe 6 (the flow direction of the steam is shown as an arrow 13 in fig. 2), flows out from the steam outlet 2 and enters the condenser for condensation. After releasing a part of water, the dilute solution 12 increases in concentration, gradually increases in concentration and continues downwards, and when reaching the bottom, the dilute solution becomes the concentrated solution 14, flows into the solution tank 8, and then flows into the absorber from the concentrated solution outlet 9 of the solution tank 8 to continue circulation. The utility model discloses in, set up flue gas emission outlet 7 in the side of generator housing 5, help the absorption heat pump to carry out waste heat recovery with the flue gas.
For the engineering design and experimental requirements, the calculation model of the heat transfer process of the vertical falling film generator is shown as follows. The standThe whole heat transfer process of the falling film generator is a composite heat transfer form of convection heat transfer and radiation heat transfer, and the qualitative temperature t ismComprises the following steps:
Figure BDA0002657507350000041
in the formula (1), twThe temperature generated in the heat exchange corrugated pipe (designed according to the working condition requirement), tfIs the air temperature at combustion; according to the qualitative temperature tmPhysical parameters of air such as kinematic viscosity upsilon, thermal conductivity coefficient upsilon, prandtl number Pr and volume expansion coefficient alpha can be found in a dry air thermal physical property table of heat transfer science, and the gradaff number Gr is as follows:
Figure BDA0002657507350000042
in the formula (2), g is the gravity acceleration, and l is the length of the heat exchange corrugated pipe (designed according to the requirement); calculating the product of the Grafaff number and the Gr Prandtl number Pr; according to the formula of the vertical wall rule, and considering the wall temperature as a constant, the Nu is as follows:
Nu＝0.1×(Gr·Pr)1/3 (3)
the convective heat transfer coefficient is hc：
Figure BDA0002657507350000043
Radiative heat transfer coefficient hrComprises the following steps:
Figure BDA0002657507350000051
in the formula (5), ε represents an emissivity value, CbThe radiation coefficient is, the heat transfer coefficient of the composite heat exchange outside the heat exchange corrugated pipe is as follows:
h＝hr+hc (6)
the area a of the heat exchange bellows is:
Figure BDA0002657507350000052
in the formula (7), Q is the heat generated by the fuel gas, and Delta T is the heat exchange temperature difference.
In summary, the length and the number of the tube bundles of the heat exchange corrugated tubes can be calculated according to the system load (namely, a calculation model of the heat transfer process of the vertical falling film generator), and the number of the tube bundles can be determined according to the area and the length.
Although the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit of the present invention.

Claims (3)

1. A vertical falling film generator for a gas-air source absorption heat pump system comprises a burner (1) and a generator shell (5), wherein a discharge pipeline of the burner (1) vertically penetrates through the generator shell (5) in sequence, a liquid distributor (4) is arranged at the top in the generator shell (5), the liquid distributor (4) is provided with a dilute solution inlet (3) and a steam outlet (2), a smoke discharge outlet (7) is arranged in the middle of the side wall of the generator shell (5), a solution tank (8) is arranged at the bottom in the generator shell (5), and a concentrated solution outlet (9) is arranged at the bottom of the solution tank (8); the method is characterized in that:
a plurality of heat exchange corrugated pipes (6) are arranged between the liquid distributor (4) and the solution tank (8), the top ends of the heat exchange corrugated pipes (6) are communicated with the liquid distributor (4), the bottom ends of the heat exchange corrugated pipes (6) are communicated with the solution tank (8), and the bottom ends of the heat exchange corrugated pipes (6) are higher than the liquid level of the concentrated solution (14) in the solution tank (8); a conical barrel plug-in piece (10) is coaxially arranged in each heat exchange corrugated pipe (6), the top position of the conical barrel plug-in piece (10) is higher than the top position of the heat exchange corrugated pipe (6), and a gap is reserved between the pipe wall of the heat exchange corrugated pipe (6) and the conical barrel plug-in piece (10).
2. The vertical falling film generator according to claim 1, wherein the heat exchange bellows (6) has an area a;
if the whole heat transfer process of the vertical falling film generator is a composite heat transfer mode of convection heat transfer and radiation heat transfer, the qualitative temperature tmComprises the following steps:
Figure DEST_PATH_FDA0002855770050000011
in the formula (1), twIs the temperature, t, occurring in the heat exchange corrugated pipefIs the air temperature at combustion; according to the qualitative temperature tmAnd physical parameters of the air are found in a thermal physical property table of dry air in the 'heat transfer science', wherein the physical parameters comprise kinematic viscosity upsilon, heat conductivity coefficient lambda, prandtl number Pr and volume expansion coefficient alpha, and the Gravadaff number Gr is as follows:
Figure DEST_PATH_FDA0002855770050000012
in the formula (2), g is the gravity acceleration, and l is the length of the heat exchange corrugated pipe; calculating the product of the Grafaff number and the Gr Prandtl number Pr; according to the formula of the vertical wall rule, the wall temperature is constant, and the Nu is as follows:
Nu＝0.1×(Gr·Pr)1/3 (3)
the convective heat transfer coefficient is hc：
Figure DEST_PATH_FDA0002855770050000013
Radiative heat transfer coefficient hrComprises the following steps:
Figure DEST_PATH_FDA0002855770050000014
in the formula (5), ε represents an emissivity value, CbThe radiation coefficient is, the heat transfer coefficient of the composite heat exchange outside the heat exchange corrugated pipe is as follows:
h＝hr+hc (6)
the area a of the heat exchange bellows is:
Figure DEST_PATH_FDA0002855770050000021
in the formula (7), Q is the heat generated by the fuel gas, and Delta T is the heat exchange temperature difference.
3. Vertical falling film generator according to claim 2, characterized in that the number and diameter of the heat exchange bellows (6) in the vertical falling film generator are designed according to the length l and the area A of the heat exchange bellows (6).
CN202021852556.0U 2020-08-31 2020-08-31 Vertical falling film generator for gas air source absorption heat pump system Expired - Fee Related CN212692166U (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111998570A (en) * 2020-08-31 2020-11-27 天津大学 Vertical falling film generator for gas air source absorption heat pump system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111998570A (en) * 2020-08-31 2020-11-27 天津大学 Vertical falling film generator for gas air source absorption heat pump system

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