WO2017088772A1

WO2017088772A1 - Refrigerant evaporator of no-circulation pump of absorption type refrigeration unit, refrigeration unit and matrix

Info

Publication number: WO2017088772A1
Application number: PCT/CN2016/106974
Authority: WO
Inventors: 邱伟; 杨如民; 武祥辉; 武维建; 刘彦武
Original assignee: 四川捷元科技有限公司
Priority date: 2015-11-26
Filing date: 2016-11-23
Publication date: 2017-06-01
Also published as: CN106802030A; CN106802030B

Abstract

Provided are a refrigerant evaporator (101) of a no-circulation pump of an absorption type refrigeration unit, an absorption type refrigeration unit and a refrigeration matrix. The refrigerant evaporator (101) of the no-circulation pump comprises: a plurality of diversion grooves (204) arranged in an upper and lower layers. Heat transfer tubes (203, 305) are laid over the respective layers of the diversion grooves (204). A refrigerant water flows outside the heat transfer tubes (203, 305). Cold water is circulated inside the heat transfer tubes (203, 305). A plurality of discharge holes (302) are provided on the side wall of the diversion groove (204) to enable the refrigerant water to flow to the diversion grooves (204) at the lower layer, so as to keep the refrigerant submerging the heat transfer tubes (203, 305). The refrigerant evaporator (101) of the non-circulation pump uses the heat transfer tubes (203, 305) having the small diameter, the thin wall and the large density, to obtain the larger heat exchange area per unit volume so as to meet the requirements of small volume and high heat exchange efficiency. The diversion groove (204) for guiding a flow is provided below each row of the heat transfer tubes (203, 305) to allow the refrigerant water to contact with and have heat exchange with the heat transfer tubes (203, 305) in the diversion groove (204), and to allow the refrigerant water flowing in a shell pass not to have to fill all of the space of the shell pass and to only necessarily submerge the the heat transfer tube (203,305).

Description

Absorption refrigeration unit without circulating pump refrigerant evaporator, refrigeration unit and matrix

Technical field

The invention relates to the field of production of a lithium bromide absorption refrigerating machine, in particular to a small absorption refrigerating machine capable of being a separate unit of a refrigerating matrix and a non-circulating pump refrigerant evaporator therein.

Background technique

The absorption chiller has the advantages of energy saving, environmental protection, etc. It is easy to use new energy such as solar energy and industrial waste heat waste heat, and has been continuously developed. Miniaturization and familyization will be another trend after it has been put into industrial applications.

The lithium bromide absorption chiller uses pure water as the refrigerant, that is, it relies on pure water to evaporate and absorb heat in a high vacuum environment to realize the refrigeration function. The refrigerant vapor after the endothermic evaporation is absorbed, transported, heated and regenerated, condensed by the lithium bromide solution, and returned to the liquid state again, and then again absorbs heat and evaporates, and the source continuously performs the refrigeration cycle.

In the foregoing process, the means for achieving evaporation endotherm is called an evaporator. Due to the physical and chemical properties of pure water, the evaporation temperature of the evaporator is usually set at about 5 °C for various refrigeration applications that meet the needs of human comfort. This requires that the saturation pressure in the working chamber of the evaporator must be maintained at 872 Pa. about. This kind of pressure has high requirements on the airtightness of the refrigerator. In order to ensure the high vacuum sealing performance, the traditional absorption refrigerator has to be made of a very thick steel plate or casting, and the heat exchange tube is made of copper. Shell-and-tube heat exchange structure. The chiller is bulky, heavy, and has poor corrosion resistance.

In addition, if a shell-and-tube heat exchanger is used to form a non-circulating pump refrigerant evaporator, the refrigerant generally flows in the shell side; since the absolute evaporation of the refrigerant is relatively small, if the circulation amount of the refrigerant water supplied by the shell side is equal to or only slightly As the evaporation of the refrigerant, as the refrigerant evaporates, the refrigerant fluid is continuously reduced, so that the heat exchange tube cannot be sufficiently wetted to cause a "dry spot" on the outer surface of the heat exchange tube. The appearance of dry spots greatly reduces the heat transfer coefficient of the heat exchanger. Therefore, in order to ensure sufficient wetting, it is often necessary to configure a dedicated refrigerant pump in the shell side, using a refrigerant water body far more than the actual evaporation amount, and continuously pumping the refrigerant water without evaporation from the bottom of the evaporator under the pump pumping of the refrigerant pump. Spray to the top of the evaporator. The existence of a refrigerant pump increases the volume and weight of the refrigerator and increases the operating cost on the other hand. Therefore, there is an urgent need to make new improvements to the structure of the evaporator to meet the requirements of lighter, more efficient, more energy-saving and environmentally friendly.

Summary of the invention

In order to solve the above technical problems, the present invention aims to provide a non-circulating pump refrigerant evaporator for an absorption refrigeration unit. The so-called absorption refrigeration unit refers to a small lithium bromide absorption chiller with a complete refrigeration function, which can be used alone or in combination with a large-scale refrigeration matrix.

The specific technical solutions are as follows:

An absorption refrigeration unit without circulating pump refrigerant evaporator, comprising:

a plurality of rows of flow guiding grooves arranged in upper and lower layers;

Laying a heat exchange tube above each layer of the flow guiding groove;

The refrigerant water flows outside the heat exchange tube, and the cold water circulates inside the heat exchange tube;

A plurality of drain holes are arranged on the side wall of the guide trough to allow the refrigerant water to flow to the lower flow guiding trough to keep the refrigerant liquid immersed in the heat exchange tube.

Further, the flow guiding groove is a rectangular shallow groove;

The side wall of the guide trough facing the absorber is a sloping liquid barrier for trapping the refrigerant water and allowing only the refrigerant vapor to pass.

Further, the upper and lower sides of the bottom wall of the guide groove are provided with support bars at an angle of 45° to 135° with the edge of the guide groove, and the support bar is used for supporting the heat exchange tube and changing the refrigerant water in the flow guide groove. The direction of flow creates turbulence.

Further, the drain hole is in an inverted triangle on the sloped liquid barrier of the flow guiding groove.

Further, the drain holes on the adjacent two-layer flow guiding grooves are staggered from each other in the vertical direction.

Further, the flow guiding groove makes the flow path of the refrigerant liquid form a zigzag shape for extending the heat exchange time of the refrigerant liquid and the heat exchange tube and generating turbulence.

Further, the flow guiding groove is made of engineering plastic; the heat exchange tube is made of stainless steel material.

Further, the combined action of the drain hole and the diversion tank, after entering a stable working condition, the refrigerant water accumulated in the diversion tank just immerses the heat exchange tube;

The refrigerant water circulating from the regenerator and the condenser is additionally replenished to the first row of the flow guiding trough of the evaporator, and the sum of the evaporation of the refrigerant water in each row of the diversion trough is exactly equal to the replenishing amount of the refrigerant water, and the evaporator does not have to be used. Refrigerant circulation pump.

A second object of the present invention is to provide an absorption refrigeration unit comprising the foregoing The absorption refrigeration unit has no circulating pump refrigerant evaporator.

A third object of the present invention is to provide an absorption refrigeration system comprising a plurality of absorption refrigeration units, the absorption refrigeration unit comprising an absorption refrigeration unit without a circulation pump refrigerant evaporator as described above.

The beneficial effects of the invention are:

The non-circulating pump refrigerant evaporator of the invention adopts a heat exchange tube with small diameter, thin tube wall and high density, and obtains a large heat exchange area per unit volume, so as to meet the requirements of small volume and high heat exchange efficiency; A diversion trough is arranged under the heat exchange tube to allow the refrigerant water to contact the heat exchange tube for heat exchange in the diversion tank, so that the refrigerant water flowing in the shell side does not need to fill the entire space of the shell, and only needs to be submerged. The heat exchange tube can be used to reduce the amount of the refrigerant water body; the V-shaped (inverted triangle) drain hole is arranged in the liquid barrier of the flow guiding groove, and the refrigerant fluid can be automatically adjusted in the guide groove according to the flow rate of the refrigerant. The deposition height makes the refrigerant water evenly infiltrate the heat exchange tube when the refrigeration load is small and the refrigerant flow rate is small, thereby reducing the chance of "dry spots" on the surface of the heat exchange tube and increasing the evaporation heat transfer coefficient; The invention also adopts new materials and new processes: the evaporator discards expensive metal materials and replaces engineering plastics with stronger corrosion resistance and easier molding; the heat exchange tubes discard expensive brass materials and replace them with more corrosion-resistant stainless steel. Material.

DRAWINGS

1 is a schematic perspective view showing the assembly of a non-circulating pump refrigerant evaporator of the present invention;

Figure 2A is a cross-sectional view of the non-circulating pump refrigerant evaporator of the present invention;

Figure 2B is a partial enlarged view of the circular area of Figure 2A;

3 is a schematic view showing the structure of a guide groove of a non-circulating pump refrigerant evaporator of the present invention.

Among them, some of the structures or parts in the figure are marked as follows:

Evaporator 101;

Absorber 102;

Concentrated solution supply hole 103;

Refrigerant water orifice 104;

Condenser bottom partition 201;

Throttle 202;

Evaporator heat exchange tube 203;

Guide groove 204;

Absorber heat exchange tube 205;

Solution dispenser 206;

Regenerator bottom partition 207;

Absorber solution outlet 208;

Evaporator refrigerant water return port 209;

Sloping liquid barrier 210;

The first row of the flow guiding groove 301 of the evaporator;

Inverted triangular drain hole 302;

Sloping liquid barrier 303;

Support strip 304;

Heat exchange tube 305;

O-ring 306;

Absorber guide groove 307.

detailed description

The drawings constitute a part of the specification; various embodiments of the invention are described below with reference to the accompanying drawings. It should be understood that, for convenience of description, the present invention uses terms that indicate direction, such as "front", "back", "upper", "lower", "left", "right", etc. to describe each of the present invention. Example structural parts and elements, but these directional terms are only determined in accordance with the example orientations shown in the figures. Since the disclosed embodiments can be arranged in different orientations, these terms are merely illustrative and should not be taken as limiting. Wherever possible, the same or similar reference numerals are used to refer to the same parts.

As shown in FIG. 1, the evaporator 101 and the absorber 102 are disposed in the same cavity; the refrigerant water required by the evaporator 101 is supplied by the refrigerant water orifice 104 at the bottom of the condenser disposed above the absorber 102. The concentrated solution required is supplied from the concentrated solution supply hole 103 at the bottom of the regenerator disposed above it.

2A is a cross-sectional view of the non-circulating pump refrigerant evaporator of the present invention, and FIG. 2B is a partial enlarged view of the circular area of FIG. 2A.

As shown in FIG. 2A and FIG. 2B, the heat exchange tube of the present invention adopts a compact layout, and adopts a heat exchange tube having a small diameter, a thin tube wall, and a high density. As an embodiment, the evaporator 101 is an array of tube bundles of 15 tubes and 36 tubes per row symmetrically and evenly arranged by an evaporator heat exchange tube 203 having a nominal outer diameter of 3 mm; in the horizontal direction, two adjacent heat exchangers The center distance of the tube is 3.5 to 4.5 mm; in the vertical direction, the center distance between two adjacent heat exchange tubes is 6.5 to 7.5 mm; the fluid flowing in the tube is cold water; the fluid flowing outside the tube is refrigerant water. Such a design makes the evaporator 101 of the present invention virtually a compact shell-and-tube heat exchange structure having a large heat transfer area to volume ratio.

In the evaporator 101, the two rows of evaporator heat exchange tubes 203 adjacent to each other are separated by a flow guiding groove 204. There are 36 diversion channels in the 36 rows of heat exchange tubes. The adjacent two flow guiding grooves 204 and the surrounding evaporator heat exchange tubes 203 constitute a shell-and-tube heat exchanger; therefore, the evaporator 101 is actually formed by 36 shell-and-tube heat exchangers. Each of the flow guiding grooves 204 is manufactured by precision injection molding, and the contact surface of the flow guiding groove 204 and the evaporator heat exchange tube 203 is sealed by an O-ring 306 (see FIG. 3) to ensure airtightness and watertightness.

In the initial state, the refrigerant water accumulates on the bottom partition 201 of the condenser; the refrigerant water is throttled and reduced by the orifice 202 on the bottom partition 201, and then flows to the internal guide groove 204 of the evaporator 101 (see FIG. 1). In the first row of diversion channels. By rationally designing the drain hole 302 (see FIG. 3) on the flow guiding groove 204, the refrigerant water accumulates in the first row of the flow guiding groove to the first row of heat exchange tubes which just submerged the heat exchange tube bundle 203; Under the action of the holes 302, the refrigerant water sequentially flows through the subsequent rows of the flow guiding grooves in the guiding grooves 204.

In each row of the flow guiding trough, the refrigerant water exchanges heat with the cold water flowing through the tube of the evaporator heat exchange tube 203, and some of the refrigerant water absorbs heat to evaporate into a refrigerant vapor, and at the same time, the evaporator heat exchange tube 203 is tube-passed. The cold water temperature is lowered; there is no vaporized refrigerant water in the flow guiding groove 204, and returns to the absorber through the return hole 209 at the bottom of the evaporator 101 under the action of gravity. The vaporized vapor vaporized in the evaporator diversion tank flows through the ramped liquid barrier 210 to the absorber 205 where it is absorbed by the solution dispensed from the solution dispenser 206.

The entire process of returning the refrigerant water from the orifice 202, to the evaporator 205, and back to the absorber from the return orifice 209 is all done by gravity. And the refrigerant water in the 36 diversion tanks is immersed and exchanged with the heat exchange tubes, and the refrigerant water supplied from the orifices 202 passes through the first row during steady state operation under rated cooling conditions. The guide trough, when it reaches the last row of diversion troughs, is completely evaporated, eliminating the need for a circulation pump.

3 is a schematic view showing the structure of a guide groove of a non-circulating pump refrigerant evaporator of the present invention;

Figure 3 shows the first three rows of flow guiding grooves in the flow guiding groove 204 of Figure 2 . The first row of the flow guiding groove 301 of the evaporator is a rectangular guiding groove located below the heat exchange tube 305. Both sides of the groove bottom of the guide groove 301 are provided with support strips 304 at an angle of 45 to 135 degrees from the edge of the flow guiding groove 301. The support strips 304 are used to support the heat exchange tubes 305, and at the same time, the support strips also change the flow direction of the refrigerant water flowing in the flow guide grooves 301 and generate turbulence. The support strip 304 is not only the support of the heat exchange tube 305 but also the flow guiding device of the refrigerant water. It not only functions to transmit the vacuum pressure, but also guides the flow of the refrigerant water along the meandering path through the heat exchange tubes 305 to increase the flow distance of the refrigerant water. Produces turbulence effects.

A sloped liquid barrier 303 is provided at the left side edge of the flow guiding groove 301 for trapping droplets that may be entrained in the refrigerant vapor. Four bleed holes 302 are provided in the slope of the side of the liquid barrier 303 facing the flow guiding groove 301 for uniformly distributing the refrigerant water in the flow guiding groove 301 into the lower flow guiding groove. The flow and distribution of the refrigerant water effluent through the flow guiding groove 301 allows the refrigerant water to uniformly flow through each row of the heat exchange tubes, thereby effectively preventing the free fall of the refrigerant water from forming a splash phenomenon, and the refrigerant water is from top to bottom. When flowing through each row of heat exchange tubes 305, the heat of the cold water flowing inside the tube of the heat exchange tubes 305 is better absorbed.

The bleed hole 302 is an inverted triangle, and the bleed hole 302 can automatically adjust the deposition height of the refrigerant water in the flow guiding groove 301 according to the flow rate of the refrigerant: when the flow rate of the refrigerant water is large, the liquid height reaches the upper portion of the bleed hole 302. The liquid discharge amount is increased; when the flow rate of the refrigerant water is small, the liquid level is low, and the liquid discharge amount is also reduced through the lower portion of the drain hole 302. Therefore, when the refrigeration load is small and the refrigerant flow rate is small, the refrigerant water can uniformly infiltrate the heat exchange tube 305, reduce the chance of "dry spots" on the surface of the heat exchange tube 305, and improve the heat transfer coefficient.

In all the guide channels behind the first row of guide channels 301, the same bleed holes 302 are provided, but the layers are staggered in the following manner: the drain holes of the upper layer and the adjacent lower layer The drain hole cannot be directly connected, and the refrigerant water from the upper drain hole cannot be directly dropped to the next layer drain hole, but is first dropped onto the slope type liquid barrier 303, and then on the liquid barrier 303 and the support strip 304. The heat exchange tube 305 flowing through the flow guiding groove 301 is combined; the heat exchanged with the fluid of the heat transfer tube 305 is passed through the drain hole 302 to the next layer. This design makes the flow path of the refrigerant water form a "Z" shape, and the contact heat exchange time between the refrigerant water and the surface of the heat exchange tube is greatly increased; the flow path of the refrigerant water is disturbed many times, which increases the flow turbulence effect and improves the effect. Heat exchange efficiency.

While the invention will be described with respect to the specific embodiments illustrated in the drawings, it is understood that the non-circulating pump refrigerant evaporator and absorption refrigeration unit and refrigeration of the present invention without departing from the spirit, scope and background of the present teachings. The matrix can have many variations, such as a change in the shape of the flow channel, a change in the size of the bleed hole, and the like. It will be appreciated by those skilled in the art that various changes in the parameters and dimensions of the disclosed embodiments are intended to be included within the spirit and scope of the invention.

Claims

An absorption refrigeration unit without circulating pump refrigerant evaporator, characterized in that it comprises:

a plurality of rows of flow guiding grooves arranged in upper and lower layers;

Laying a heat exchange tube above each layer of the flow guiding groove;

The refrigerant water flows outside the heat exchange tube, and the cold water circulates inside the heat exchange tube;

A plurality of drain holes are arranged on the side wall of the flow guiding groove, so that the refrigerant water flows to the lower layer guiding groove to keep the refrigerant liquid immersed in the heat exchange tube.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to claim 1, wherein:

The flow guiding groove is a rectangular shallow groove; the flow guiding groove is provided with a slope type liquid blocking plate toward the absorber side for trapping the refrigerant water, and only the refrigerant vapor is allowed to pass.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to claim 1, wherein:

The upper and lower sides of the flow guiding groove are provided with a supporting strip at an angle of 45° to 135° with the edge of the guiding groove, and the supporting strip is used for supporting the heat exchange tube and changing the refrigerant in the guiding groove The flow direction of water produces turbulence.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to claim 1, wherein:

The bleed hole is in an inverted triangle on the sloping liquid barrier of the flow guiding groove.
A non-circulating pump refrigerant evaporator for an absorption refrigeration unit according to claim 4, wherein:

The drain holes on the adjacent two-layer flow guiding grooves are staggered in the vertical direction.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to claim 1, wherein:

The flow guiding groove makes the flow path of the refrigerant liquid form a zig-zag shape for extending the refrigerant liquid and The heat exchange time of the heat exchange tubes generates turbulence.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to claim 1, wherein:

The flow guiding groove is made of engineering plastic; the heat exchange tube is made of stainless steel material.
The non-circulating pump refrigerant evaporator of an absorption refrigeration unit according to any one of claims 1 to 7, characterized in that: the combined action of the drain hole and the guide groove, after entering a stable working condition, the guide The refrigerant water accumulated in the flow cell just immerses the heat exchange tube;

The refrigerant water circulating from the regenerator and the condenser is additionally replenished to the first row of the flow guiding trough of the evaporator, and the sum of the evaporation of the refrigerant water in each row of the diversion trough is exactly equal to the replenishing amount of the refrigerant water, and the evaporator does not have to be used. Refrigerant circulation pump.
An absorption refrigeration unit characterized by:

A non-circulating pump refrigerant evaporator for an absorption refrigeration unit according to any one of claims 1-8.
An absorption refrigeration matrix characterized by:

Including a plurality of absorption refrigeration units;

The absorption refrigeration unit includes the absorption refrigeration unit without circulation pump refrigerant evaporator according to any one of claims 1-8.