CN112082401A

CN112082401A - Heat exchanger and heat exchanger system

Info

Publication number: CN112082401A
Application number: CN202011036238.1A
Authority: CN
Inventors: 陈奇良; 李峰; 郝海青; 周孝清; 毛凯; 姜恒
Original assignee: Guangzhou University
Current assignee: Guangzhou University
Priority date: 2020-09-27
Filing date: 2020-09-27
Publication date: 2020-12-15

Abstract

The invention relates to the technical field of heat exchangers, and discloses a heat exchanger and a heat exchanger system. The heat exchanger comprises a calandria and fins, secondary refrigerant or heat carrying agent can be introduced into the calandria, the fins are arranged on the outer wall of the calandria, and the height of the fins extends along the radial direction of the calandria. The heat conductivity coefficient of the fins is smaller than that of the calandria. According to the heat exchanger provided by the invention, the heat conductivity coefficient of the fins is lower, the fins have an isolation effect, the phase-change solid substances on the two sides of the calandria are separated under the cooling-releasing working condition, the phase-change solid substances are prevented from annularly wrapping the calandria, the time for separating the phase-change solid substances under the heating working condition is shortened, the input heat is reduced, and the cooling capacity in the cooling-heating period is improved; the phase-change solid substance on the calandria can be removed quickly, so the thermal resistance formed by the phase-change solid substance can be limited to a lower value, thereby greatly improving the cooling and heat exchange efficiency of the heat exchanger.

Description

Heat exchanger and heat exchanger system

Technical Field

The invention relates to the technical field of heat exchangers, in particular to a heat exchanger and a heat exchanger system.

Background

Along with the improvement of living standard of people, the demand of energy is more and more large, such as refrigeration of a central air conditioner, heating in winter in the north, logistics cold supply chain, large-scale heat storage and cold storage and the like. The heat transfer between the cold and the hot involves the use of heat exchangers. For conventional fluid medium heat transfer and exchange, the high heat exchange efficiency can be realized by improving the heat conductivity coefficient of the heat exchanger material, increasing the heat exchange area and improving the flow speed of the conventional fluid, and the national requirements on energy conservation and emission reduction can be met. However, some heat exchanger systems involve phase change of the medium, especially gas-solid and liquid-solid phase change heat transfer systems, which are often complicated. When the fluid medium receives cold or releases heat, the fluid medium is changed into solid by phase change, and the fluid medium often wraps the heat exchanger; and the thickness of the solid is larger and larger along with the time, because the heat conduction system of the phase-change solid substance is not very large and is generally between 0.1 and 3W/(m.K), the heat resistance generated by the solid substance is larger and larger, the heat exchange efficiency of the heat exchanger is seriously influenced, meanwhile, the flow velocity of the fluid medium is increased, and the improvement of the heat exchange efficiency of the heat exchanger is very little.

At present, the cold energy is transmitted to the fluid medium at the temperature lower than the phase change temperature, when the thickness of the solid substance is too large, the heat exchanger is switched to a heating mode to the temperature higher than the phase change temperature, so that the surface of the phase change solid substance attached to the heat exchanger is liquefied, and finally the solid substance falls off from the heat exchanger. However, this liquefaction time is often relatively long, which results in a large loss of transmitted refrigeration. Therefore, it is necessary to optimize the structure of the heat exchanger related to such phase change, accelerate the falling time of the phase change solid matter, reduce the loss of cooling capacity, and improve the heat exchange efficiency of the heat exchanger.

Disclosure of Invention

A first object of the present invention is to provide a heat exchanger, which can shorten the time for phase-change solid substances to escape and improve the heat exchange efficiency of the heat exchanger.

The second purpose of the invention is to provide a heat exchanger system, which can make the phase-change solid substance fall off quickly by applying the heat exchanger, thereby improving the heat exchange efficiency of the heat exchanger system.

In order to achieve the purpose, the invention adopts the following technical scheme:

a heat exchanger, the heat exchanger comprising:

the heat exchange assembly comprises a row pipe and fins, secondary refrigerant or heat carrier can be introduced into the row pipe, the fins are arranged on the outer wall of the row pipe, and the height of the fins extends along the radial direction of the row pipe;

the heat conductivity coefficient of the fins is smaller than that of the calandria.

As the preferred scheme of the heat exchanger, at least two groups of the heat exchange assemblies are arranged at intervals, the heat exchanger further comprises connecting pipes and heat insulation layers, the first ends of the adjacent two calandria pipes are communicated through the connecting pipes, the heat insulation layers wrap the connecting pipes, and the heat conductivity coefficient of the heat insulation layers is smaller than that of the calandria pipes.

As a preferable mode of the heat exchanger, the fins are symmetrically arranged on both sides of the row tube.

Preferably, in the heat exchanger, the plate surface of the fin is parallel to the axis of the row tube.

As a preferable scheme of the heat exchanger, the heat conductivity coefficient of the calandria is 5-500W/(m.k); and/or

The heat conductivity coefficient of the fin is 0.01-0.3W/(m.K).

As a preferable scheme of the heat exchanger, the calandria is made of copper, aluminum or stainless steel material; and/or

The fins are made of plastic or rubber.

As a preferable scheme of the heat exchanger, the heat conduction coefficient of the heat-insulating layer is 0.01-0.3W/(m.K).

Preferably, the heat-insulating layer is made of plastic or rubber.

A heat exchanger system comprising a heat exchanger as described above.

The heat exchanger system preferably further comprises a switching valve, a low-temperature cold source and a high-temperature heat source, wherein the low-temperature cold source and the high-temperature heat source are connected with the discharge pipe through the switching valve so as to introduce a secondary refrigerant or a heat-carrying agent into the discharge pipe.

The invention has the beneficial effects that:

according to the heat exchanger provided by the invention, when the cooling working condition is adopted, the row tubes are introduced with the secondary refrigerant for cooling, the heat conductivity coefficient of the fins is smaller than that of the row tubes, the growth speed of the phase-change solid substances on the fins is very slow, the fins have a certain height, and the phase-change solid substances on the two sides of the row tubes generally cannot cross the tops of the fins to be connected into a whole, so that the fins have an isolation effect; when the solid matter on the calandria and the fin grows to a certain thickness and the growth speed becomes very slow, the heat carrier is introduced into the calandria, so that the surface temperature of the calandria and the fin exceeds the melting temperature of the solid matter, the phase-change solid matter attached to the surfaces of the calandria and the fin is liquefied quickly, and the solid matter falls off from the two sides of the calandria easily under the action of gravity due to the difference between the solid density and the liquid density of the phase-change solid matter. After the solid matter falls off, the secondary refrigerant can be introduced into the calandria again, so that a cooling-heating periodic heat exchange process is formed. The heat exchanger provided by the invention has the following advantages: (1) the heat conductivity coefficient of the fins is lower than that of the calandria, and the fins have an isolation effect, so that the phase change solid substances on the two sides of the calandria are isolated under the cooling condition, a cylindrical solid block is avoided, the phase change solid substances are prevented from completely wrapping the calandria, the time for separating the phase change solid substances under the heating condition is greatly shortened, the input heat is reduced, and the cooling capacity in the cooling-heating period is improved; (2) the phase-change solid substance on the calandria can be removed quickly, so that the thermal resistance formed by the phase-change solid substance can be limited to a lower value, thereby greatly improving the cold-releasing and heat-exchanging efficiency of the heat exchanger and greatly shortening the cold-releasing time; (3) the heat conductivity coefficient of the calandria is higher, so that the heat exchange efficiency of the heat exchanger can be improved, and the cold release rate under the cold release working condition is accelerated; (4) the heat exchange efficiency is improved, so that the volume of the heat exchanger can be effectively reduced, and the manufacturing cost of equipment is reduced.

According to the heat exchanger system provided by the invention, the phase change solid substance can be quickly dropped off by applying the heat exchanger, so that the heat exchange efficiency of the heat exchange system is improved.

Drawings

FIG. 1 is a schematic structural diagram of a heat exchanger according to a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a row of tubes and fins provided by an embodiment of the invention;

FIG. 3 is a cross-sectional view of a row of tubes and fins provided in accordance with one embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a heat exchanger system according to a second embodiment of the present invention;

fig. 5 is a schematic structural diagram of a heat exchanger system according to a third embodiment of the present invention.

In the figure:

1-a heat exchanger; 11-calandria; 12-a fin; 13-a connecting tube; 14-insulating layer; 15-entrance and exit;

2-a cold storage tank;

3, filtering the filter screen;

4-a circulation assembly; 41-a circulation pipeline; 411-inlet; 412-an outlet; 42-a valve; 43-a water pump; 44-water distributor spray head;

5-a switching valve;

6-low temperature cold source and high temperature heat source.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

As shown in fig. 1-3, the present embodiment provides a heat exchanger, in which the heat exchanger 1 includes a heat exchange assembly, the heat exchange assembly includes a row tube 11 and fins 12, a coolant or a heat carrier can be introduced into the row tube 11, the fins 12 are disposed on an outer wall of the row tube 11, and a height of the fins 12 extends along a radial direction of the row tube 11. The heat conductivity of the fins 12 is smaller than that of the row tubes 11.

In the heat exchanger provided by the embodiment, when the cooling working condition is met, the row tubes 11 are introduced with the coolant to perform cooling, because the heat conductivity coefficient of the fins 12 is smaller than that of the row tubes 11, the growth speed of the phase-change solid substances on the fins 12 is very slow, and the fins 12 have a certain height, the phase-change solid substances on two sides of the row tubes 11 generally cannot cross the tops of the fins 12 to be connected into a whole, so the fins 12 play an isolation role; when the solid matters on the calandria 11 and the fins 12 grow to a certain thickness and the growing speed becomes very slow, the heat carrier is introduced into the calandria 11, so that the surface temperature of the calandria 11 and the fins 12 exceeds the melting temperature of the solid matters, the phase-change solid matters adhered to the surfaces of the calandria 11 and the fins 12 are liquefied quickly, and the solid matters are easy to fall off from the two sides of the calandria 11 under the action of gravity because the solid density and the liquid density of the phase-change solid matters are different. After the solid matter falls off, the coolant can be introduced into the calandria 11 again, so as to form a cooling-heating periodic heat exchange process. In this embodiment, the solid phase of the phase change material is ice, and the liquid phase is water. The secondary refrigerant is glycol solution.

The heat exchanger that this embodiment provided has following advantage: (1) the heat conductivity coefficient of the fins 12 is lower than that of the exhaust pipe 11, and the fins 12 have an isolation effect, so that the phase change solid substances on two sides of the exhaust pipe 12 are separated under the cooling-releasing working condition, a cylindrical solid block is avoided, the phase change solid substances are prevented from completely wrapping the exhaust pipe 11, the time for separating the phase change solid substances under the heating working condition is greatly shortened, the input heat is reduced, and the cooling capacity in the cooling-heating period is improved; (2) because the phase-change solid substance on the calandria 11 can be removed quickly, the thermal resistance formed by the phase-change solid substance can be limited to a lower value, thereby greatly improving the cold-releasing and heat-exchanging efficiency of the heat exchanger and greatly shortening the cold-releasing time; (3) the heat conductivity coefficient of the calandria 11 is higher, so that the heat exchange efficiency of the heat exchanger 1 can be improved, and the cold release rate under the cold release working condition is accelerated; (4) the volume of the heat exchanger 1 can be effectively reduced and the manufacturing cost of the equipment can be reduced due to the improvement of the cooling and heat exchange efficiency.

The heat exchanger provided by the implementation is based on the large guidance of energy efficient utilization, energy conservation, environmental protection and emission reduction, and is oriented to the industry requirement of novel energy-saving technology application, and the industrial requirement with the efficient heat exchange engineering with phase change as the final target can meet the refrigeration requirement of a large central air conditioner, the centralized heat supply in winter in the north, the logistics cold supply chain, the large heat storage and cold storage and the like can be effectively utilized, and the economic benefit is improved.

Alternatively, the fins 12 are symmetrically arranged on both sides of the gauntlet 11. That is, the fins 12 on both sides of the calandria tube 11 can divide the phase-change solid substance on both sides of the calandria tube 11 into two pieces. Of course, in other embodiments, the fins 12 may be disposed not only on both sides of the row tube 11, but also uniformly along the circumferential direction of the row tube 11. Further, the plate surface of the fin 12 is parallel to the axis of the row tube 11. Of course, the plate surface of the fin 12 may be not only parallel to the axis of the exhaust pipe 11, but also perpendicular to the axis of the exhaust pipe 11, as long as the thermal conductivity of the fin 12 is lower than that of the exhaust pipe 11, which is not limited herein.

In the present embodiment, the fins 12 are rectangular. Further, the length of the rectangle is equal to the length of the gauntlet 11. Of course, in other embodiments, the fins 12 may be not only rectangular, but also trapezoidal, and the plate surfaces of the fins 12 may not be flat, for example, wavy plate surfaces, and the like, and the heat conductivity of the fins 12 is not limited herein as long as the heat conductivity is lower than that of the exhaust pipes 11.

Optionally, the thermal conductivity of the gauntlet 11 is 5-500W/(m.K). The heat conductivity coefficient of the calandria 11 is high, which is beneficial to improving the heat exchange efficiency of the heat exchanger and accelerating the cooling rate under the cooling working condition.

Alternatively, the gauntlet 11 is made of copper, aluminum or stainless steel material. Specifically, in the present embodiment, the gauntlet tube 2 is made of a stainless steel material.

Optionally, the fins 12 have a thermal conductivity of 0.01-0.3W/(m.K). The heat conductivity coefficient of the fins 12 is low, so that the phase change solid substances on two sides of the calandria 11 can be prevented from crossing the tops of the fins 12 to be connected into a whole, an isolation effect is achieved, and the time for separating the phase change solid substances under the ice removing working condition is shortened.

Optionally, the fins 12 are made of plastic or rubber. Such as polyethylene, polypropylene, polyvinyl chloride or polytetrafluoroethylene, etc. Specifically, in the present embodiment, the fins 12 are made of polypropylene.

Specifically, the second end of the discharge tube 11 is provided with an inlet/outlet 15, and the coolant and the heat-transfer agent can enter the discharge tube 1 through the inlet/outlet 15 or be discharged from the discharge tube 1.

Further, at least two sets of heat exchange assemblies are arranged at intervals, the heat exchanger 1 further comprises a connecting pipe 13 and an insulating layer 14, the first ends of the two adjacent calandria 11 are communicated through the connecting pipe 13, the insulating layer 14 wraps the connecting pipe 13, and the heat conductivity coefficient of the insulating layer 14 is smaller than that of the calandria 11. In order to prevent the phase change solid matter, i.e. ice, from forming an annular ice layer at the connecting pipe 13, which is not beneficial to quick falling, the connecting pipe 13 is wrapped with an insulating layer 14 with a low thermal conductivity coefficient. In this embodiment, the rack of gauntlets is also wrapped with an insulating layer 14.

Optionally, the plate surfaces of the fins 12 in at least two sets of heat exchange assemblies are in the same plane.

Optionally, the thermal conductivity of the insulating layer 14 is 0.01-0.3W/(m.K). The heat conductivity coefficient of the insulating layer 14 is low, so that the connecting pipe 13 is prevented from being wrapped by the phase change solid substance, and the falling speed of the phase change solid substance is increased.

Optionally, the insulation layer 14 is made of plastic or rubber. Such as expanded polyurethane or expanded polystyrene, etc.

Example two

As shown in fig. 4, the present embodiment provides a heat exchanger system, including the heat exchanger 1 provided in the first embodiment, further including a switching valve 5, and a low-temperature cold source and a high-temperature heat source 6, where the low-temperature cold source and the high-temperature heat source 6 are connected to the discharging pipe 11 through the switching valve 5, so as to introduce a coolant or a heat carrier into the discharging pipe 11. Specifically, in the present embodiment, the switching valve 5 is a four-way valve. When the working condition of cooling is in, the low-temperature cold source is communicated with the calandria 11 by switching the switching valve 5, so as to introduce the secondary refrigerant into the calandria 11; when the heating working condition is met, the high-temperature heat source is communicated with the discharge pipe 11 through the switching of the switching valve 5, so that the heat carrier is introduced into the discharge pipe 11.

EXAMPLE III

As shown in fig. 5, the present embodiment provides a heat exchanger system, which includes the heat exchanger 1 provided in the first embodiment, and further includes a cold storage tank 2, a filter screen 3, a circulation assembly 4, a switching valve 5, and a low temperature cold source and a high temperature heat source 6. The cold storage tank 2 is filled with water and ice. The filter screen 3 is installed on the upper part of the cold storage tank 2 and is immersed in water. The circulation unit 4 includes a circulation line 41, a valve 42, a water pump 43, and a water distributor nozzle 44, an inlet 411 of the circulation line 41 is inserted into the water in the cold storage tank 2, the inlet 411 is positioned above the filter net 3, the valve 42 and the water pump 43 are both installed on the circulation line 41, an outlet 412 of the circulation line 41 is communicated with the water distributor nozzle 44, and the water distributor nozzle 44 is disposed at the lower portion of the cold storage tank 2. The heat exchanger 1 is installed in the cold storage tank 2, the heat exchanger 1 is positioned between the filter screen 3 and the water distributor nozzle 44, the calandria 11 extends along the horizontal direction, and the fins 12 are in the vertical plane.

In order to improve the heat exchange efficiency, the heat exchanger system provided by the embodiment improves the flow rate of water in the cold storage tank 2 by adding the circulation component 4, wherein the water pump 43 sucks the unfrozen water on the upper part of the cold storage tank 2 into the circulation pipeline 41 from the inlet 411, pumps the water to the outlet 412 through the valve 42, and makes the water uniformly impact the surface of the heat exchanger 1 through the water distributor nozzle 44, so that the heat exchange efficiency is greatly improved, and meanwhile, the ice layer can be quickly dropped off under the ice removing working condition.

It should be noted that the structures and the operating principles of the switching valve 5, the low temperature cold source and the high temperature heat source 6 in this embodiment are the same as those in this embodiment, and are not described herein again.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A heat exchanger, characterized in that the heat exchanger (1) comprises:

the heat exchange assembly comprises a row pipe (11) and fins (12), secondary refrigerant or a heat carrier can be introduced into the row pipe (11), the fins (12) are arranged on the outer wall of the row pipe (11), and the height of the fins (12) extends along the radial direction of the row pipe (11);

the heat conductivity coefficient of the fins (12) is smaller than that of the row tubes (11).

2. The heat exchanger according to claim 1, wherein at least two groups of the heat exchange assemblies are arranged at intervals, the heat exchanger (1) further comprises a connecting pipe (13) and an insulating layer (14), the first ends of two adjacent rows of tubes (11) are communicated through the connecting pipe (13), the insulating layer (14) wraps the connecting pipe (13), and the thermal conductivity of the insulating layer (14) is smaller than that of the rows of tubes (11).

3. Heat exchanger according to claim 1, characterized in that said fins (12) are symmetrically arranged on both sides of said row of tubes (11).

4. The heat exchanger according to claim 1, characterized in that the plate faces of the fins (12) are parallel to the axis of the row of tubes (11).

5. Heat exchanger according to claim 1, wherein the thermal conductivity of said gauntlet (11) is comprised between 5 and 500W/(m-K); and/or

The heat conductivity coefficient of the fin (12) is 0.01-0.3W/(m.K).

6. The heat exchanger according to claim 1, characterized in that the gauntlet (11) is made of copper, aluminum or stainless steel material; and/or

The fins (12) are made of plastic or rubber.

7. The heat exchanger according to claim 2, characterized in that the thermal conductivity of the insulating layer (14) is 0.01-0.3W/(m-K).

8. The heat exchanger according to claim 2, characterized in that the insulating layer (14) is made of plastic or rubber.

9. A heat exchanger system, characterized in that it comprises a heat exchanger (1) according to any one of claims 1-8.

10. The heat exchanger system according to claim 9, further comprising a switching valve (5) and a low temperature heat source and a high temperature heat source (6), wherein the low temperature heat source and the high temperature heat source (6) are connected with the rack pipe (11) through the switching valve (5) to feed coolant or heat carrier to the rack pipe (11).