HK1237398A - Shallow trench heat exchange mechanism for absorption-type refrigeration unit - Google Patents

Description

Shallow-groove type heat exchange mechanism of absorption refrigeration unit

Technical Field

The invention relates to the field of production of lithium bromide absorption refrigerators, in particular to a small absorption refrigerator capable of being used as a refrigeration matrix independent unit and a shallow groove type heat exchange mechanism in the small absorption refrigerator.

Background

The absorption refrigerator has the advantages of energy conservation, environmental protection and the like, is easy to use novel energy sources such as solar energy, industrial waste heat and the like, and is continuously developed. Miniaturization and family will be another trend after the application of the method to industrial fields.

The lithium bromide absorption refrigerator uses pure water as refrigerant, namely, the pure water is evaporated and absorbs heat under high vacuum environment to realize refrigeration function. The refrigerant vapor after heat absorption and evaporation is absorbed by the lithium bromide solution, transported, heated, regenerated and condensed, and then changed back to liquid state again, and then heat absorption and evaporation are carried out again, and refrigeration cycle is continuously carried out.

On the one hand, the above cycle is completed with many heat exchanges or transfers, and thus, absorption refrigerators have various heat exchangers. The most common heat exchanger has a shell-and-tube heat exchange structure with multiple layers of heat exchange tubes, and in order for an absorption refrigerator to operate effectively, the solution must be reliably and uniformly sprayed onto the surfaces of the heat exchange tubes.

The device for realizing the function of spraying the solution is the solution distributor. In a traditional absorption refrigerator, because the heat exchange pipe diameter is generally relatively thick, a solution distributor is erected at the upper part of a shell-and-tube heat exchanger, a solution is uniformly sprayed on the outer surface of the topmost row of heat exchange pipes, and then the solution flows through the outer surfaces of rows of pipes arranged below the solution distributor in sequence under the action of gravity. In order to reduce the dry spot phenomenon and improve the heat exchange efficiency, the solution is required to be uniformly and accurately distributed, so that the solution distributor has a complex structure and high production cost and is difficult to miniaturize.

On the other hand, the evaporation temperature of the evaporator is generally set to about 5 ℃ due to the physicochemical properties of pure water. Accordingly, the saturation pressure of the evaporator cavity is maintained at about 872 Pa. Compared with the atmospheric pressure (101KPa), the refrigerator is in a high vacuum environment, and the requirement on air tightness is high. In order to ensure the air tightness under high vacuum, most of the traditional large industrial absorption refrigerators adopt heavy steel plates or castings as the shell of the refrigerator, and copper pipes with relatively thick pipe diameters are matched as heat exchange pipes to form a common shell-and-tube heat exchanger structure. Accordingly, industrial absorption chillers are characterized by large volume, heavy weight, and are susceptible to corrosion by lithium bromide solutions and the generation of non-condensable gases.

In the process of miniaturization and family, one troublesome problem is that: along with the reduction of the refrigeration power, the circulation amount of the required refrigerant and the circulation amount of the lithium bromide solution are reduced, and accordingly, the unfavorable phenomenon that the outer surface of the heat exchange tube cannot be sufficiently wetted by the refrigerant or the lithium bromide solution to cause dry spots occurs.

In order to avoid dry spots, the conventional absorption refrigerator generally needs to increase the flow rate of a circulating pump, and continuously sprays liquid which is much more than the actual circulating amount from a liquid accumulation pool at the bottom of a regenerator or an absorber onto a heat exchange pipe at the top.

The flow rate of the circulating pump is increased meaninglessly, and parasitic energy consumption and operation cost are increased. It is contrary to the trend of miniaturization and family use of absorption refrigerators.

Disclosure of Invention

The present invention is to solve the above technical problems, and one of the objects of the present invention is to provide a heat exchange mechanism with high heat exchange efficiency for an absorption refrigeration unit. The heat exchange mechanism is a shallow-groove type heat exchange mechanism of an absorption refrigeration unit, comprising a shallow-groove type heat exchanger and a solution distributor, and is used for refrigeration unit parts such as a generator, an absorber and the like. The absorption refrigeration unit refers to a small lithium bromide absorption refrigerator with a complete refrigeration function, can be used independently, and also has the capacity of being combined and expanded into a large-scale refrigeration matrix.

The specific technical scheme is as follows:

a shallow slot heat exchange mechanism for an absorption refrigeration unit comprising:

the shallow-groove heat exchanger consists of a plurality of rows of flow guide grooves and heat exchange tubes which are arranged in an upper layer and a lower layer;

the solution distributor is arranged at the upper part of the shallow groove type heat exchanger;

the solution distributor is a closed cuboid, the interior of the solution distributor is a cavity, the lower portion of the solution distributor is a solution spraying surface, and solution is sprayed to the upper end face of the shallow-groove type heat exchanger below the solution distributor.

Furthermore, the diversion trench is a rectangular shallow trench and is staggered and stacked with the heat exchange tube; the heat exchange tubes are arranged on the upper portions of the diversion trenches, and the arrangement surfaces of the heat exchange tubes are parallel to the bottom surfaces of the trenches.

Further, lithium bromide solution flows outside the heat exchange tube, and water flows inside the heat exchange tube;

when the lithium bromide solution is contacted with the heat exchange tube, the lithium bromide solution is subjected to heat exchange with water in the heat exchange tube;

the flow guide groove enables the flow path of the lithium bromide solution to form a zigzag shape, and is used for prolonging the heat exchange time of the lithium bromide solution and the heat exchange tube and generating turbulence.

Furthermore, a slope-type liquid separation plate is arranged at the edge of one side of the guide groove and used for intercepting liquid drops and only allowing gas to pass through.

Furthermore, the upper surface and the lower surface of the diversion trench are provided with support bars which form a certain included angle with the edge of the diversion trench, and the support bars are used for supporting an upper pipeline and a lower pipeline and changing the flowing direction of the lithium bromide solution in the diversion trench to generate turbulent flow.

Furthermore, the included angle between the supporting bars and the edge of the flow guide groove is 45-135 degrees.

Furthermore, the shallow slot type heat exchanger adopts an immersion type heat exchange mode, and a plurality of drainage flow holes are distributed at the bottom of the diversion trench, so that the lithium bromide solution flows to the lower diversion trench and the heat exchange tube is kept immersed by the lithium bromide solution.

Furthermore, the drain holes on two adjacent layers of guide grooves are arranged in a mutually staggered manner in the vertical direction.

Furthermore, support bars which form certain included angles with the edges of the solution distributor are arranged inside the solution distributor and outside the spraying surface, and the support bars are used for supporting the inner cavity of the solution distributor and the lower heat exchange tube so as to bear the pressure generated by vacuum.

Furthermore, the included angle directions of the adjacent two rows of support bars and the edge of the solution distributor are opposite.

Further, the size of the solution spraying surface is the same as that of the upper end surface of the shallow groove type heat exchanger;

the solution spraying surface of the solution distributor is provided with a plurality of drainage holes to uniformly disperse the solution to the surface of the heat exchange tube at the lower part, so that the solution flows through each row of heat exchange tubes layer by layer from top to bottom and exchanges heat with the heat exchange liquid in the heat exchange tube.

Further, the drain hole is a rectangular hole.

Further, the drain holes are transversely arranged on the spraying surface of the solution distributor and positioned between the adjacent supporting strips.

Furthermore, the solution distributor and each row of the diversion trenches of the shallow trench type heat exchange mechanism are all made of engineering plastics; the heat exchange tube is made of stainless steel materials.

It is another object of the present invention to provide an absorption refrigeration unit, which includes the shallow-tank heat exchange mechanism of the absorption refrigeration unit.

A third object of the present invention is to provide an absorption refrigeration matrix, which comprises a plurality of absorption refrigeration units;

the absorption refrigeration unit comprises the shallow groove type heat exchange mechanism of the absorption refrigeration unit.

The invention has the beneficial effects that:

the invention enables the solution to fully infiltrate the heat exchange tube, effectively eliminates the dry spot phenomenon and reduces the splashing phenomenon of the solution; the solution flows along the lengthened zigzag path, so that the contact heat exchange time with the heat exchange tube is increased, turbulence is generated, and the heat exchange efficiency is improved; the structure of the solution distributor is simplified, the reduction of the volumes of the heat exchanger and the solution distributor is realized, and the miniaturization of the absorption refrigeration unit adopting the heat exchange mechanism is facilitated.

Drawings

FIG. 1 is a cross-sectional partial structural view of a shallow sump heat exchange mechanism of an absorption refrigeration unit of the present invention;

FIG. 2 is an assembled perspective view of the shallow slot heat exchange mechanism of the absorption refrigeration unit of the present invention with some components removed;

FIG. 3 is an exploded view of the assembly of the shallow channel heat exchange mechanism of the absorption refrigeration unit with portions of the components removed;

fig. 4 is a schematic diagram of an arrangement structure of heat exchange tubes of the shallow-groove heat exchange mechanism of the absorption refrigeration unit of the present invention.

Wherein the parts are labeled as follows:

a solution dispenser 101;

a heat exchange pipe 102;

a first row of diversion trenches 103;

a second row of launders 104;

a liquid barrier 105;

a condenser/absorber 106;

the bottom 207 of the solution distributor 101;

a support strip 208;

drain hole 209;

a lower portion 210 of the first drainage chute 103;

heat exchange tubes 504, 506, 508.

Detailed Description

The accompanying drawings form a part of the specification; various embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that directional terms, such as "front," "rear," "upper," "lower," "left," "right," and the like, may be used herein to describe various example features and elements of the invention for purposes of illustration, but are only determined by the example orientations shown in the figures. Because the disclosed embodiments of the invention can be arranged in a variety of orientations, these directional terms are used for purposes of illustration only and are not to be construed as limiting. Wherever possible, the same or similar reference numbers used herein refer to the same or like parts.

Fig. 1 is a cross-sectional partial structural view of a shallow groove heat exchange mechanism of an absorption refrigeration unit of the present invention.

The shallow-groove type heat exchange mechanism of the absorption refrigeration unit is simultaneously suitable for a regenerator and an absorber of the refrigeration unit. The regenerator is used for heating the lithium bromide dilute solution by using a heat exchange pipe (102 in figure 1) with hot water flowing through the inside, so that water molecules in the dilute solution are continuously vaporized, and water vapor enters a condenser to be condensed into refrigerant water; the absorber is used for cooling the lithium bromide concentrated solution by using a heat exchange pipe (102 in figure 1) with cooling water flowing inside, so that the surface vapor pressure of the concentrated solution is reduced, and the solution can continuously absorb the refrigerant vapor flowing from the evaporator. The shallow-groove type heat exchange mechanism of the absorption refrigeration unit is suitable for heating dilute solution and cooling concentrated solution. The heat exchange structures under the two applications are completely the same. Hereinafter, the regenerator will be described as an example.

Fig. 1 shows a partial structural view of a cross section of a shallow channel heat exchange mechanism of an absorption refrigeration unit, wherein a regenerator 100 comprises: a solution distributor 101, a heat exchange pipe 102 (see fig. 4), a first discharge guide groove 103, a second discharge guide groove 104 and a liquid separation plate 105.

In fact, the regenerator 100 is a shell-and-tube heat exchange structure consisting of a plurality of heat exchange tubes densely arranged in both horizontal and vertical directions, which are layered from top to bottom in the vertical direction. The arrangement of only 3 layers of heat exchange tubes is presented in fig. 1, and the following layers are identical in structure and are not shown. Hot water flows through the heat exchange tube 102 to heat the dilute solution flowing through the heat exchange tube.

The diversion grooves 103 and 104 are arranged between every two layers of heat exchange tubes, the diversion grooves 103 and 104 not only play a role in diversion, but also are used for supporting the heat exchange tubes arranged on the diversion grooves, dilute solution flows through the diversion grooves and contacts with the heat exchange tubes, the longer the flow, the longer the heat exchange contact time, and the better the heat exchange effect.

The solution distributor 101 is arranged above the top diversion trench 103, the structure of the solution distributor 101 is similar to that of the diversion trenches 103 and 104, no heat exchange tube is arranged on the solution distributor 101, and a plurality of drain holes 209 (see fig. 2) are arranged, and the drain holes 209 can distribute the dilute solution flowing on the solution distributor 101 to the surface of the heat exchange tube on the top diversion trench 103 below.

The condenser 106 is arranged at one side of the regenerator 100, moisture in the dilute solution is continuously evaporated in the regenerator 100 to form water vapor, the water vapor needs to enter the condenser 106 for heat release and condensation, but water drops in the water vapor cannot enter the condenser 106, so a slope-type liquid separation plate 105 is arranged at the end edge close to one side of the condenser 106 and used for intercepting liquid drops carried in refrigerant vapor evaporated from the dilute solution and only allowing the refrigerant vapor to go to the condenser 106.

Fig. 2 is an assembled perspective view of the shallow channel heat exchange mechanism of an absorption refrigeration unit of the present invention with portions of the components removed (including portions of the heat exchange tubes 102 and solution distributor 101).

The first drainage guide groove 103 can be seen visually in fig. 2, a plurality of rows of support bars 208 forming an angle of 45 ° to 135 ° with the edge of the guide groove 103 are alternately arranged on both sides of the bottom of the guide groove 103, and the support bars 208 are used for supporting the heat exchange tube to bear the vacuum sub-force and changing the flow direction of the dilute solution flowing in the guide groove 103 to generate turbulent flow.

The bottom of the diversion trench 103 is also provided with a plurality of drain holes 209, and the drain holes 209 are used for uniformly distributing the dilute solution to the heat exchange tube 102 below; as can be seen from fig. 2, the drain holes 209 are rectangular and alternate with the support strips 208, and the dilute solution flows into the lower diversion trench from the drain holes 209 after being disturbed by each row of the support strips 208. The supporting strips 208 and the drain holes 209 at the bottom of the diversion trench 103 act together, so that the dilute solution flowing in the diversion trench 103 can uniformly infiltrate the heat exchange tube and generate turbulent flow, and the heat exchange efficiency is improved.

Figure 3 is an exploded view of the assembly of the shallow channel heat exchange mechanism of the absorption refrigeration unit with portions of the components (including the heat exchange tubes) removed.

In fig. 3, the first layer is a solution distributor 101, the second layer is a first layer of guiding gutter 103, and the third layer is a lower layer of guiding gutter 104, and a flow path of the dilute solution after being guided by the solution distributor 101 and the guiding gutter 103 is described by taking a three-layer guiding structure as an example.

The drain holes on the two adjacent layers of flow guide grooves (103 and 104 in the figure) and the drain holes 209 on the solution distributor 101 are staggered in the vertical direction, so that the dilute solution dropping from the drain hole on the upper layer is prevented from directly dropping to the lower layer through the drain hole on the lower layer without fully exchanging heat with the heat exchange tube; meanwhile, the drainage holes 209 are matched with the supporting bars, so that the dilute solution flows under the action of gravity to form a zigzag flow path, as shown by a flow path of an arrow A in the figure, and the heat exchange time of the dilute solution and the heat exchange tube is prolonged. The structure forces the solution to change direction continuously in the diversion trenches 103 and 104, and the local turbulence strengthens the convection heat transfer coefficient between the solution and the heat exchange tube.

The shallow-groove type heat exchange mechanism can ensure that the solution always immerses the heat exchange tube and performs immersed heat exchange with the heat exchange tube. The solution can be contacted with the heat exchange tube without multiple pumping of the solution pump. The shallow-groove type heat exchange mechanism only needs one-time pumping, and parasitic energy consumption of the solution pump can be saved.

FIG. 4 is a schematic diagram of an arrangement structure of heat exchange tubes of the shallow-groove heat exchange mechanism of the absorption refrigeration unit of the present invention;

FIG. 4 is a schematic cross-sectional view of two rows of heat exchange tubes, wherein the distance D between the centers of adjacent heat exchange tubes 504 and 506 is 4mm in the same layer; the distance between the centers of the adjacent heat exchange tubes 506 and 508 is 7mm in the upper layer and the lower layer. The heat exchange tubes are all of the same 3mm pipe diameter, and the extremely fine heat exchange tubes and the compact arrangement structure obtain extremely high heat transfer area in unit volume, so that the efficiency of the heat exchanger is improved.

The solution distributor and the diversion trenches in the regenerator 100 are made of engineering plastics with strong corrosion resistance and easy molding, and the weight of the refrigeration unit is effectively reduced. The heat exchange tube is made of stainless steel materials, so that the corrosion resistance is improved, and the air tightness is effectively guaranteed.

Although the present invention will be described with reference to the particular embodiments shown in the drawings, it should be understood that the shallow sump heat exchange mechanism of an absorption refrigeration unit, and the refrigeration unit and refrigeration matrix in which it is used, of the present invention can take many forms without departing from the spirit, scope and background of the present teachings. Those of ordinary skill in the art will also appreciate that there are different ways of varying the parameters, dimensions, and so forth of the disclosed embodiments of the invention that fall within the spirit and scope of the invention and the appended claims.

Claims (16)

1. The utility model provides an absorption refrigeration unit shallow slot type heat transfer mechanism which characterized in that includes:

the shallow-groove heat exchanger consists of a plurality of rows of flow guide grooves and heat exchange tubes which are arranged in an upper layer and a lower layer;

the solution distributor is arranged at the upper part of the shallow groove type heat exchanger;

the solution distributor is a closed cuboid, the interior of the solution distributor is a cavity, the lower portion of the solution distributor is a solution spraying surface, and solution is sprayed to the upper end face of the shallow-groove type heat exchanger below the solution distributor.

2. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

the diversion trench is a rectangular shallow trench and is staggered and stacked with the heat exchange tube;

the heat exchange tubes are arranged on the upper portions of the diversion trenches, and the arrangement surfaces of the heat exchange tubes are parallel to the bottom surfaces of the trenches.

3. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

lithium bromide solution flows outside the heat exchange tube, and water flows inside the heat exchange tube;

when the lithium bromide solution is contacted with the heat exchange tube, the lithium bromide solution is subjected to heat exchange with water in the heat exchange tube;

the flow guide groove enables the flow path of the lithium bromide solution to form a zigzag shape, and is used for prolonging the heat exchange time of the lithium bromide solution and the heat exchange tube and generating turbulence.

4. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

and a slope-type liquid separation plate is arranged at the edge of one side of the flow guide groove and is used for intercepting liquid drops and only allowing gas to pass through.

5. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

the upper surface and the lower surface of the diversion trench are provided with support bars which form a certain included angle with the edge of the diversion trench, the support bars are used for supporting an upper pipeline and a lower pipeline, and the flowing direction of a lithium bromide solution in the diversion trench is changed to generate turbulent flow.

6. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 5 wherein:

the included angle between the supporting bars and the edge of the flow guide groove is 45-135 degrees.

7. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

the shallow slot type heat exchanger adopts an immersion type heat exchange mode, and a plurality of drainage flow holes are distributed at the bottom of the diversion trench, so that the lithium bromide solution flows to the lower diversion trench and the heat exchange tube is kept immersed in the lithium bromide solution.

8. The absorption refrigeration unit shallow trough heat exchange mechanism of claim 7 wherein:

and the discharge holes on two adjacent layers of guide grooves are arranged in a staggered manner in the vertical direction.

9. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

and supporting bars which form a certain included angle with the edge of the solution distributor are arranged inside the solution distributor and outside the spraying surface, and the supporting bars are used for supporting the inner cavity of the solution distributor and the lower heat exchange tube so as to bear the pressure generated by vacuum.

10. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 9 wherein:

the included angle directions of the adjacent two rows of support bars and the edge of the solution distributor are opposite.

11. The absorption refrigeration unit shallow tank heat exchange mechanism of claim 1 wherein:

the size of the solution spraying surface is the same as that of the upper end surface of the shallow-groove type heat exchanger;

the solution spraying surface of the solution distributor is provided with a plurality of drainage holes to uniformly disperse the solution to the surface of the heat exchange tube at the lower part, so that the solution flows through each row of heat exchange tubes layer by layer from top to bottom and exchanges heat with the heat exchange liquid in the heat exchange tube.

12. The absorption refrigeration unit shallow trough heat exchange mechanism of claim 11 wherein:

the drain hole is a rectangular hole.

13. The absorption refrigeration unit shallow trough heat exchange mechanism of claim 11 wherein:

the drain holes are transversely disposed on the spray face of the solution distributor between adjacent support strips.

14. The absorption refrigeration unit shallow tank heat exchange mechanism of claims 1-13 wherein:

the solution distributor and each row of the diversion trenches of the shallow-trench heat exchange mechanism are all made of engineering plastics; the heat exchange tube is made of stainless steel materials.

15. An absorption refrigeration unit, characterized by:

comprising the shallow channel heat exchange mechanism of an absorption refrigeration unit of any of claims 1-14.

16. An absorption refrigeration matrix, characterized by:

comprises a plurality of absorption refrigeration units;

the absorption refrigeration unit comprising the absorption refrigeration unit shallow channel heat exchange mechanism of any of claims 1-14.