High-efficiency hot water type lithium bromide absorption type unit with upper structure and lower structure

Abstract

The utility model provides an efficient hot water type lithium bromide absorption unit arranged in an up-down structure, which is characterized in that an evaporator, an absorber and a generator all adopt two-stage heat exchange, and a condenser adopts single-stage heat exchange; the unit mainly comprises two independent solution circulation loops, a refrigerant pipeline, a first-stage generator and a second-stage generator, a second-stage evaporator and a first-stage evaporator are connected in series through a pipeline, and a first-stage absorber and a second-stage absorber are connected in parallel through a pipeline and then connected with a condenser in series. The first-stage generator and the second-stage generator are arranged left and right, the first-stage generator and the condenser are arranged up and down, the first-stage evaporator and the first-stage absorber are arranged up and down, and the second-stage evaporator and the second-stage absorber are arranged up and down. According to the unit, the consumption of high-grade heat energy is reduced or replaced by recovering medium-low temperature waste heat water in a factory, so that the comprehensive utilization efficiency of energy is improved, meanwhile, the overall structure of the unit is compact, and the occupied area is reduced due to the up-and-down structural arrangement.

Description

Technical Field

[0001] The utility model relates to the technical field of waste heat heating and refrigeration, and in particular to a high-efficiency hot water type lithium bromide absorption unit with an upper and lower structural arrangement. Background Art

[0002] Industrial production processes are often accompanied by the generation of a large amount of medium and low temperature waste heat. Due to the low temperature, it cannot be further utilized by the process. Usually, water cooling or air cooling is used to discharge the heat into the environment, resulting in a waste of heat energy. Therefore, strengthening the recovery and utilization of waste heat is the main way to save energy, which involves the application of various high-efficiency energy-saving equipment, waste heat recovery and utilization equipment and energy-saving technologies. Various lithium bromide absorption heat pumps and chillers based on lithium bromide absorption technology are driven by thermal energy, with lithium bromide solution as the absorbent and water as the refrigerant. They recycle the heat energy of waste hot water to achieve heating and cooling.

[0003] According to the different driving heat sources, they are generally divided into hot water type, steam type and direct-fired absorption units. Under most working conditions, medium and low temperature waste heat exists in the form of condensed water, heat medium water and cooling medium. Among them, hot water with a temperature of ≥90℃ can be used as the driving heat source for hot water absorption heat pumps and chiller generators, and hot water with a lower temperature between 25-50℃ can be used as the low-temperature heat source for hot water absorption heat pump evaporators.

[0004] The existing hot water absorption unit is composed of an evaporator, an absorber, a generator, a condenser, a solution heat exchanger, a solution pump, a refrigerant pump, a control system, and pipes and valves connecting the various components. Figure 1 , 2 As shown, the first-stage evaporator 61 and the first-stage absorber 51, the second-stage evaporator 62 and the second-stage absorber 52, the generator 3 and the condenser 4 are all arranged on the left and right, the first-stage evaporator 61 is directly above the second-stage evaporator 62, and the two are separated into independent spaces by the refrigerant plate at the bottom of the first-stage evaporator 61; the first-stage absorber 51 is directly above the second-stage absorber 52, and the two are separated into independent spaces by the solution plate at the bottom of the first-stage absorber 51; the generator 3 is arranged directly above the first-stage evaporator 61, and the condenser 4 is arranged directly above the first-stage absorber 51.

[0005] In actual applications, the unit adopts a left-right layout structure, which results in a large overall unit structure, high manufacturing cost, and large project construction investment, which is not conducive to the unit water pipeline configuration and vacuum pipeline configuration. At the same time, the left-right layout also makes the air flow rise height of each chamber in the unit small, and the lithium bromide droplets of the generator are easy to enter the condenser, and the lithium bromide droplets in the absorber are also easy to enter the evaporator, causing refrigerant water pollution. At the same time, when waste hot water is used as a driving heat source or a low-temperature heat source for heating, the temperature of the waste hot water fluctuates with the continuous changes in working conditions, so the temperature of the waste hot water may sometimes be low. The common lithium bromide absorption unit has only one generator. When the temperature of the waste hot water as a driving hot water is low, the temperature rise of the heating water is limited, which may cause the outlet temperature of the heating water to be low and fail to meet the water supply temperature requirements; similarly, the cooling range of the cold water is limited, which may cause the outlet temperature of the cold water to be high and fail to meet the water supply temperature requirements. Therefore, there is currently a lack of efficient lithium bromide absorption units that can make a single unit have high heat exchange efficiency, occupy a small area, and improve the overall performance coefficient of the unit. Summary of the invention

[0006] In view of this, the utility model aims to propose a high-efficiency hot water absorption unit with an upper and lower structural arrangement to solve the problems of low heat exchange efficiency and large floor space of lithium bromide absorption units in the prior art.

[0007] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0008] A high-efficiency hot water type lithium bromide absorption unit with an upper and lower structure arrangement, wherein the evaporator, absorber and generator all adopt two-stage heat exchange, and the condenser adopts single-stage heat exchange, and the unit mainly includes two independent solution circulation loops and a refrigerant pipeline;

[0009] The first-stage generator and the second-stage generator are connected in series through pipelines, which improves the thermal energy utilization rate of the generator and also enables the generator to perform two steam generation processes step by step, thereby increasing the released absorption heat; the second-stage evaporator and the first-stage evaporator are connected in series through pipelines, and the two-stage evaporators provide sufficient refrigerant steam. The series connection enables the water side of the internal heat exchange pipe of the evaporator to release heat step by step, thereby reducing the heat loss of the evaporator and improving the thermal energy utilization rate of the water side of the heat exchange pipe of the evaporator; the first-stage absorber and the second-stage absorber are connected in parallel through pipelines. The two absorbers are connected in parallel through pipelines, which has a compact structure and reduces the footprint. At the same time, the two absorbers release the absorption heat at the same time, thereby improving the heat exchange efficiency of the absorber; and then connected in series with the condenser, the condensation latent heat released by the condenser heats the water side of the internal heat exchange pipe again, thereby reducing the heat loss on the water side and increasing the heat exchange efficiency of the unit.

[0010] The condenser is arranged at the top of the unit, and the first-stage generator and the second-stage generator are arranged on the left and right, forming an up-and-down arrangement structure with the condenser. The condenser is connected to the vacuum side of the first-stage generator and the second-stage generator respectively; the first-stage absorber and the second-stage absorber are arranged in parallel at the bottom of the unit; the first-stage evaporator and the first-stage absorber are arranged up and down, and the vacuum side is connected; the second-stage evaporator and the second-stage absorber are arranged up and down, and the vacuum side is connected. The up-and-down arrangement structure, in which the evaporator is located on the upper part of the absorber and the condenser is located on the upper part of the generator, reduces the number of rows of heat exchange tubes in each chamber, increases the distance between the two-stage generator and the two-stage absorber, saves materials, and reduces the volume.

[0011] Furthermore, the solution circulation loop is divided into a first-stage solution circulation loop and a second-stage solution circulation loop, the first-stage solution circulation loop mainly includes a first-stage generator, a first-stage solution heat exchanger, a first-stage solution pump, a first-stage absorber and pipelines; the second-stage solution circulation loop mainly includes a second-stage generator, a second-stage solution heat exchanger, a second-stage solution pump, a second-stage absorber and pipelines.

[0012] Furthermore, the first-stage solution circulation loop and the second-stage solution circulation loop are connected in parallel, which can better adapt to the temperature conditions of the absorber and the generator water side and the working pressure of the absorber and the generator vacuum side in each loop, thereby achieving a better heat exchange effect.

[0013] Furthermore, the condenser is connected to the first-stage evaporator through a pipeline, and the second-stage evaporator is connected to the first-stage evaporator and the refrigerant pump through pipelines, respectively, to form a refrigerant pipeline.

[0014] Furthermore, the refrigerant pump, the first-stage evaporator, and the second-stage generator are connected in parallel to form a refrigerant water spray pipeline. The parallel connection mode only requires the installation of one refrigerant pump, which reduces the operating parts of the unit, reduces the power consumption of the unit, and improves the reliability of the unit operation.

[0015] Furthermore, a first-stage generation-condensation liquid baffle is arranged between the condenser and the first-stage generator, a second-stage generation-condensation liquid baffle is arranged between the condenser and the second-stage generator, a first-stage evaporation-absorption liquid baffle is arranged between the first-stage evaporator and the first-stage absorber, and a second-stage evaporation-absorption liquid baffle is arranged between the second-stage evaporator and the second-stage absorber.

[0016] Furthermore, the first-stage generator and the second-stage generator are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate; the first-stage absorber and the second-stage absorber are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate; the first-stage evaporator and the second-stage evaporator are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate.

[0017] Furthermore, the bottoms of the condenser, the first-stage evaporator, and the second-stage evaporator are all provided with a refrigerant tray; the bottoms of the first-stage generator, the second-stage generator, the first-stage absorber, and the second-stage absorber are all provided with a solution tray.

[0018] Furthermore, the first-stage generator, the second-stage generator, the first-stage absorber, the second-stage absorber, the first-stage evaporator, the second-stage evaporator and the condenser are each a heat exchange chamber, and multiple rows of heat exchange tube bundles are installed in each heat exchange chamber, and each heat exchange tube bundle is composed of multiple heat exchange tubes placed horizontally.

[0019] Furthermore, a spray device is provided above the heat exchange tubes of the first-stage generator, the second-stage generator, the first-stage absorber, the second-stage absorber, the first-stage evaporator and the second-stage evaporator.

[0020] Compared with the prior art, the high-efficiency hot water type lithium bromide absorption unit with an upper and lower structure arrangement described in the utility model has the following advantages:

[0021] The utility model reduces or replaces the consumption of high-grade thermal energy by recycling the medium and low temperature waste hot water of the factory, thereby improving the comprehensive utilization efficiency of energy; the evaporator, absorber and generator all adopt two-stage heat exchange, and the condenser adopts single-stage heat exchange to reduce the irreversible heat loss in the heat transfer process, improve the performance of the unit, and is more conducive to the structural layout of the unit, which is conducive to reducing the manufacturing cost; at the same time, two independent solution circulation loops are formed, and the lithium bromide solutions of the two circulation loops are not interconnected and have different concentrations, which can better adapt to the temperature conditions of the water side of the absorber and the generator in their respective loops and the working pressure of the vacuum side of the absorber and the generator. By adjusting the working concentrations of the lithium bromide concentrated solution and the dilute solution of the two solution circulation loops, the heat loads of the two-stage evaporator, the two-stage absorber and the two-stage generator are more balanced, the total heat exchange area of ​​the unit is reduced, the material cost is reduced, and the performance coefficient of the unit is improved; the number of refrigerant pumps and refrigerant pipelines is controlled, the pipeline configuration of the refrigerant water circulation system is optimized, which is conducive to the water pipeline configuration and vacuum pipeline configuration of the unit, and the overall structure of the unit is compact and occupies a small space. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of a lithium bromide absorption heat pump unit in the prior art;

[0023] Figure 2 It is a schematic diagram of the structure of a lithium bromide absorption chiller in the prior art;

[0024] Figure 3 This is a schematic diagram of Embodiment 1 of the present utility model;

[0025] Figure 4This is a schematic diagram of Embodiment 2 of the present utility model;

[0026] Description of Reference Numerals

[0027] Solution pump 1, first-stage solution pump 11, second-stage solution pump 12; refrigerant pump 2; generator 3, first-stage generator 31, second-stage generator 32; condenser 4; first-stage absorber 51, second-stage absorber 52; first-stage evaporator 61, second-stage evaporator 62; solution heat exchanger 7, first-stage solution heat exchanger 71, second-stage solution heat exchanger 72; first heat exchange tube bundle 311, second heat exchange tube bundle 321; third heat exchange tube bundle 411; fourth heat exchange tube bundle 511, fifth heat exchange tube bundle 521; sixth heat exchange tube bundle 611, seventh heat exchange tube bundle 621; first first-stage solution tray 312, second-stage solution tray 322; first-stage refrigerant tray 412; third-stage solution tray 512, fourth-stage solution tray 522; second-stage refrigerant tray 612, third-stage refrigerant tray 622; first-stage generation-condensation baffle plate 81, second-stage generation-condensation baffle plate 82; first-stage evaporation-absorption baffle plate 91, second-stage evaporation-absorption baffle plate 92; refrigerant water flow channel 10; first-stage dilute solution circuit 131, second-stage dilute solution circuit 132; first-stage concentrated solution circuit 141; second-stage concentrated solution circulation circuit 142; refrigerant water spray pipeline 15. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Figure 3 , 4 This is an implementation diagram of a high-efficiency hot water type lithium bromide absorption unit with an upper and lower structural arrangement involved in the utility model. The unit includes an evaporator, an absorber, a generator and a condenser, wherein the evaporator, the absorber and the generator all adopt two-stage heat exchange, and the condenser 4 adopts a single-stage heat exchange. The unit is a vacuum device with extremely high airtightness requirements (it can form a low-pressure environment to make the refrigerant water evaporate at a low temperature). In order to maintain the vacuum state inside the unit, an exhaust device is provided in the unit. This exhaust device can be a mechanical vacuum pump exhaust system or an automatic exhaust system. The exhaust device is not shown in the figure because it does not belong to the application scope of this patent.

[0030] The condenser 4 is arranged at the uppermost part of the unit, the first-stage generator 31 and the second-stage generator 32 are arranged on the left and right, and are arranged up and down with the condenser 4. The condenser 4 is connected to the vacuum side of the first-stage generator 31, and the condenser 4 is connected to the vacuum side of the second-stage generator 32; the first-stage absorber and the second-stage absorber are arranged in parallel at the lowermost part of the unit, and the vertical heights of the two are flush; the first-stage evaporator 61 and the first-stage absorber 51 are arranged up and down, and the vacuum sides are connected; the second-stage evaporator 62 and the second-stage absorber 52 are arranged up and down, and the vacuum sides are connected;

[0031] The upper and lower structural arrangement is adopted, and the arrangement mode in which the evaporator is located on the upper part of the absorber reduces the number of tube rows of the evaporator and the absorber; the condenser is arranged on the upper part of the two-stage generator, which also reduces the number of tube rows of the generator, reduces the liquid level of the solution, reduces the influence of the static liquid column on the generation process, improves the heat exchange effect of the generator, and at the same time reduces the number of tube rows of the condenser, which improves the heat transfer coefficient; on the other hand, the distance between the two-stage generator and the two-stage absorber is widened, ensuring the normal flow of the concentrated solution in the solution circulation system, achieving the purpose of increasing the driving force of mass transfer, and the pressure difference between the generator and the absorber makes the solution spray heat exchange in the absorber, which can increase the contact area between the refrigerant steam and the spray solution and enhance the heat exchange efficiency. Finally, the condenser adopts a single-stage structure to ensure the excellent performance of the unit, and only one refrigerant pump needs to be installed to form a refrigerant pipeline; the number of refrigerant pumps is reduced, the operating parts of the unit and the power consumption of the unit are reduced, and the pipeline configuration of the refrigerant water circulation system is optimized, which is more conducive to the structural layout of the unit. Taking all factors into consideration, the upper and lower structural arrangement saves materials, reduces volume, and lowers economic costs, while also improving heat transfer efficiency.

[0032] The unit mainly includes two independent solution circulation loops and a refrigerant pipeline. The first-stage solution heat exchanger 71 is connected to the first-stage solution tray 312 at the bottom of the first-stage generator 31 and the spray device at the top of the first-stage absorber 51 through pipelines, forming a first-stage concentrated solution loop 141; the first-stage solution heat exchanger 71 is connected to the first-stage solution pump 11, the third-stage solution tray 512 at the bottom of the first-stage absorber 51 and the spray device at the top of the first-stage generator 31 through pipelines, forming a first-stage dilute solution loop 131; wherein the first-stage dilute solution loop 131 and the first-stage concentrated solution loop 141 together constitute a first-stage solution circulation loop; similarly, the second-stage generator 32, the second-stage solution heat exchanger 72, the second-stage solution pump 12 and the second-stage absorber 52 are connected through pipelines, forming a second-stage solution circulation loop together. A vertical partition plate is installed between the first-stage absorber 51 and the second-stage absorber 52 to separate the vacuum sides of the two into independent spaces. The lithium bromide solutions in the two circulation loops are not connected to each other, have different concentrations, and are independent of each other, so as to better adapt to the temperature conditions on the water side of the absorber and the generator in their respective loops and the working pressure on the vacuum side of the absorber and the generator; the first-stage refrigerant plate 412 at the bottom of the condenser 4 is connected to the first-stage evaporator 61, and the second-stage evaporator 62 is respectively connected to the first-stage evaporator 61 and the refrigerant pump 2 to form a refrigerant pipeline. The condenser 4 and the first-stage The evaporator 61 is connected in one direction to form a refrigerant water return pipeline; the refrigerant pump 2 is connected in parallel with the first-stage evaporator 61 and the second-stage evaporator 62 through a spray device; a first-stage generation-condensation liquid baffle 81 is arranged between the condenser 4 and the first-stage generator 31, a second-stage generation-condensation liquid baffle 82 is arranged between the condenser 4 and the second-stage generator 32, a first-stage evaporation-absorption liquid baffle 91 is arranged between the first-stage evaporator 61 and the first-stage absorber 51, and a second-stage evaporation-absorption liquid baffle 92 is arranged between the second-stage evaporator 62 and the second-stage absorber 52.

[0033] The condenser 4, the first-stage evaporator 61, and the second-stage evaporator 62 are all provided with a refrigerant pan at the bottom, which is used to store unevaporated or collected condensed water. The first-stage generator 31, the second-stage generator 32, the first-stage absorber 51, and the second-stage absorber 52 are all provided with a solution pan at the bottom, which is used to collect the lithium bromide solution falling from the outside of the heat exchange tube bundle. The first-stage generator 31, the second-stage generator 32, the first-stage absorber 51, the second-stage absorber 52, the first-stage evaporator 61, the second-stage evaporator 62, and the condenser 4 are each a heat exchange chamber, and multiple rows of heat exchange tube bundles are installed in each heat exchange chamber, and each heat exchange tube bundle is composed of multiple heat exchange tubes placed horizontally. The inside of the heat exchange tube is the waterway side, and the outside of the heat exchange tube is the vacuum side. Spraying devices are provided above the heat exchange tubes of the first-stage generator 31, the second-stage generator 32, the first-stage absorber 51, the second-stage absorber 52, the first-stage evaporator 61, and the second-stage evaporator 62.

[0034] Embodiment 1

[0035] As one embodiment of the utility model, the device structure and connection method are the same as above, the first-stage generator 31 and the second-stage generator 32 are connected in series through a pipeline, the second-stage evaporator 62 and the first-stage evaporator 61 are connected in series through a pipeline, and the first-stage absorber 51 and the second-stage absorber 52 are connected in parallel through a pipeline, and then connected in series with the condenser 4; when the high-efficiency hot water type lithium bromide absorption unit with an upper and lower structure arrangement is in a heating condition, it is specifically manifested as follows:

[0036] The first heat exchange tube bundle 311 inside the first-stage generator 31 is connected to the second heat exchange tube bundle 321 inside the second-stage generator 32 through pipelines, and the two heat exchange tube bundles are respectively connected to the driving hot water inlet and the driving hot water outlet, and the waste hot water inlet is connected to the seventh heat exchange tube bundle 621 inside the second-stage evaporator 62, and the sixth heat exchange tube bundle 611 inside the first-stage evaporator 61 is respectively connected to the seventh heat exchange tube bundle 621 inside the second-stage evaporator 62 and the waste hot water outlet; the fourth heat exchange tube bundle 511 inside the first-stage absorber 51 is respectively connected to the heating water inlet and the fifth heat exchange tube bundle 521 inside the second-stage absorber 52 through pipelines, and the third heat exchange tube bundle 411 inside the condenser 4 is respectively connected to the fourth heat exchange tube bundle 511 inside the first-stage absorber 51, the fifth heat exchange tube bundle 521 inside the second-stage absorber 52 and the heating water outlet through pipelines.

[0037] The hot water is driven as a high-temperature heat source to enter the first-stage heat exchange tube 311 inside the first-stage generator 31 and the second-stage heat exchange tube bundle 321 inside the second-stage generator 32. The dilute lithium bromide solution on the vacuum side outside the tube enters the first-stage generator 31 and the second-stage generator 32 through the top spray device, and is heated by the driving heat source in each stage of the generator to generate refrigerant steam. The dilute lithium bromide solution is concentrated into a concentrated solution and stored in the first-stage solution tray 312 at the bottom of the first-stage generator 31 and the second-stage solution tray 322 at the bottom of the second-stage generator 32. The concentrated solution is cooled by the first-stage solution heat exchanger 71 and the second-stage solution heat exchanger 72, and then enters the first-stage absorber 51 and the second-stage absorber 52 through the top spray device, absorbing the refrigerant vapor from the corresponding first-stage evaporator 61 and the second-stage evaporator 62. Heat is released during the absorption process. The lithium bromide concentrated solution absorbs the refrigerant vapor from the evaporator step by step through the two absorbers, gradually diluting the lithium bromide concentrated solution, releasing the absorption heat twice, increasing the heat source of the unit, and reducing the heat loss of the unit under the working state. At the same time, the concentrated solution becomes a dilute solution and is stored in the solution tray. The dilute solution is driven by the first-stage solution pump 11 and the second-stage solution pump 12, respectively, and then heated by the first-stage solution heat exchanger 71 and the second-stage solution heat exchanger 72 and returns to the first-stage generator 31 and the second-stage generator 32, completing two independent solution cycles. By adjusting the working concentrations of lithium bromide concentrated solution and dilute solution in the two solution circulation loops, the heat loads of the two-stage evaporator, the two-stage absorber and the two-stage generator are made more balanced, and the total heat exchange area of ​​the unit is reduced.

[0038] The refrigerant vapor generated in the first-stage generator 31 and the second-stage generator 32 passes through the first-stage generator-condensation liquid baffle plate 81 and the second-stage generator-condensation liquid baffle plate 82 for gas-liquid separation, enters the condenser 4, condenses on the external vacuum side of the heat exchange tube bundle, releases condensation heat, becomes refrigerant water and is stored in the refrigerant tray, and is sprayed into the top of the first-stage evaporator 61 through the refrigerant water reflux channel. A part of the refrigerant water absorbs the heat in the waste hot water on the outside of the heat exchange tube of the first-stage evaporator 61 and evaporates. The generated refrigerant vapor passes through the first-stage evaporation-absorption liquid baffle plate 91 and enters the first-stage absorber 51 to be absorbed by the lithium bromide concentrated solution, and the other part The unevaporated refrigerant water flows out of the first-stage evaporator 61, and enters the second-stage evaporator 62 through the refrigerant water circulation pipeline formed by the refrigerant plate at the bottom of the evaporator to continue to absorb the heat in the waste hot water and evaporate. The generated refrigerant vapor enters the second-stage absorber 52 through the second-stage evaporation-absorption baffle 92 and is absorbed by the solution. The two-stage evaporator can provide refrigerant vapor to the corresponding absorber step by step, and its refrigerant vapor output rate is significantly higher than that of the single-stage evaporator. By spontaneously maintaining a stable working pressure state, the lithium bromide concentrated solution in the corresponding absorber is promoted to absorb the refrigerant vapor, and a large amount of absorption heat is released, thereby improving the heat exchange efficiency of the unit. The remaining refrigerant water in the second-stage evaporator 62 enters the first-stage evaporator 61 under the boost drive of the refrigerant pump 2, and the top of the second-stage evaporator 62 is sprayed and evaporated, and the refrigerant water circulates back and forth.

[0039] The driving hot water as a high-temperature heat source enters the first-stage heat exchange tube 311 and the second-stage heat exchange tube bundle 321 inside the first generator 31 and the second generator 32, and performs heat exchange with the lithium bromide dilute solution on the vacuum side outside the tube in countercurrent, and uses the heat of the high-temperature hot water to heat the dilute solution, and flows out of the second-stage generator 32 along the heat exchange tube after cooling down; because the driving heat source countercurrents with the lithium bromide solution after passing through the first-stage generator 31, and enters the second-stage generator 32 after heat exchange, the irreversible heat loss in the heat transfer process can be reduced, and the driving heat source is cooled step by step. At this time, the first-stage generator 31 and the second-stage generator 32 use the same type of heat source but different temperatures, which enhances the adaptability of the unit to the heat source and improves the utilization rate of thermal energy. The two-stage generator device increases the cooling range of the driving hot water in the generator, and the content of the lithium bromide concentrated solution generated on the vacuum side is also increased, the ability to absorb refrigerant vapor is increased, and the absorption heat released is increased. The heating water absorbs heat step by step, and is heated twice, which reduces the heat loss in the heating water transportation process. At the same time, it has two independent solution circulation loops. By adjusting the working concentrations of lithium bromide concentrated solution and dilute solution in the two solution circulation loops, it can better adapt to the temperature conditions on the water side of the absorber and generator in each loop and the working pressure on the vacuum side of the absorber and generator, so that the heat load of the two-stage evaporator, two-stage absorber and two-stage generator is more balanced, achieving a better heat exchange effect.

[0040] The waste hot water serves as a low-temperature heat source and passes through the heat exchange tubes of the second-stage evaporator 62 and the first-stage evaporator 61 in sequence, exchanges heat with the refrigerant water on the vacuum side outside the tubes, evaporates the refrigerant water, and provides refrigerant steam to the corresponding absorbers step by step; the heating water inlet passes through the heat exchange tube bundle of the second-stage absorber 52, the heat exchange tube bundle of the first-stage absorber 51 and the heat exchange tube bundle of the condenser 4, and absorbs the absorption heat released by the refrigerant steam absorbed by the concentrated lithium bromide solution on the vacuum side of the absorber step by step. Compared with the existing single-stage absorber, the heating water absorbs heat step by step and is heated twice, which reduces the heat loss in the heating water transportation process. Finally, it absorbs the latent heat of condensation of the condenser 4, and the obtained heating water supply and the imported heating water return water produce a large inlet and outlet temperature difference.

[0041] Embodiment 2

[0042] Similar to the first embodiment, when the high-efficiency hot water type lithium bromide absorption unit with upper and lower structure arrangement is in refrigeration condition, the difference lies in the different inlet and outlet water connected to the unit and the different principles inside the evaporator and absorber.

[0043] The first heat exchange tube bundle 311 inside the first-stage generator 31 is connected to the second heat exchange tube bundle 321 inside the second-stage generator 32 through pipelines, and the two heat exchange tube bundles are respectively connected to the high-temperature heat source water inlet and the high-temperature heat source water outlet, and the seventh heat exchange tube bundle 621 inside the second-stage evaporator 62 and the sixth heat exchange tube bundle 611 inside the first-stage evaporator 61 are respectively connected to the cold water return inlet and the cold water supply outlet; the fourth heat exchange tube bundle 511 inside the first-stage absorber 51 is respectively connected to the cooling water inlet and the fifth heat exchange tube bundle 521 inside the second-stage absorber 52 through pipelines, and the third heat exchange tube bundle 411 inside the condenser 4 is respectively connected to the fourth heat exchange tube bundle 511 inside the first-stage absorber 51, the fifth heat exchange tube bundle 521 inside the second-stage absorber 52 and the cooling water outlet through pipelines.

[0044] The driving hot water as a high-temperature heat source enters the first-stage heat exchange tube 311 and the second heat exchange tube bundle 321 inside the first generator 31 and the second generator 32 in sequence, and performs heat exchange with the lithium bromide dilute solution on the vacuum side outside the tube in countercurrent, and uses the heat of the high-temperature hot water to heat the dilute solution, and after cooling, flows out of the second-stage generator 32 along the heat exchange tube; the two-stage generator device increases the cooling range of the driving hot water in the generator, and the content of the lithium bromide concentrated solution generated on the vacuum side is also increased. At the same time, after being cooled by cooling water in the absorber (the ability of the lithium bromide solution to absorb water vapor is proportional to the concentration and inversely proportional to the temperature), the ability of the lithium bromide concentrated solution to absorb refrigerant vapor is enhanced. In order to spontaneously maintain the same working pressure of the refrigerant vapor flow pipeline between the absorbers and evaporators at each stage, the refrigerant water in the evaporators at each stage will increase its vaporization amount, absorb a large amount of heat from the cold water return water, and produce a large inlet and outlet water temperature difference between the cold water return water and the cold water supply water, so as to better achieve the purpose of cooling. At the same time, it has two independent solution circulation loops. By adjusting the working concentrations of lithium bromide concentrated solution and dilute solution in the two solution circulation loops, it can better adapt to the temperature conditions of the water side of the absorber and generator in each loop and the working pressure of the vacuum side of the absorber and generator, so that the heat load of the two-stage evaporator, the two-stage absorber and the two-stage generator is more balanced, and a better heat exchange effect is achieved. Since the inside of the unit is in a vacuum state, a low-pressure environment can be formed, so that the refrigerant water can evaporate at a low temperature. The refrigerant water is driven by the refrigerant pump 2 in parallel and sprayed from the top into the first-stage evaporator 61 and the second-stage evaporator 62, and rapidly expands and vaporizes in the evaporator. The cold water return water passes through the heat exchange tubes of the second-stage evaporator 62 and the first-stage evaporator 61 in turn, releasing the heat required for the evaporation of the refrigerant water in the evaporator step by step. Compared with the single-stage evaporator, the cold water return water is cooled twice to obtain cold water supply, reducing the heat loss in the cold water transportation process; the cooling water pipeline passes through the heat exchange tubes of the second-stage absorber 52, the first-stage absorber 51 and the condenser 4 in turn for heat exchange, cooling the lithium bromide solution on the vacuum side outside the heat exchange tubes of the second-stage absorber 51 and the first-stage absorber 52.

[0045] Since the lithium bromide solution has a strong ability to absorb refrigerant vapor, and within a certain range, its ability to absorb refrigerant vapor is inversely proportional to the temperature of the lithium bromide solution. The ability of the lithium bromide solution to absorb refrigerant vapor after cooling on the vacuum side is enhanced. In order to spontaneously maintain the same working pressure of the refrigerant vapor flow pipeline between the absorbers and evaporators at each level, the refrigerant water in the evaporators at each level will increase its vaporization amount, absorb a large amount of heat from the cold water return water, and cause a large inlet and outlet water temperature difference between the cold water return water and the cold water supply water, so as to better achieve the purpose of cooling and cooling, and continue to cool the refrigerant vapor in the condenser 4, and generate refrigerant water to enter the refrigerant pipeline to continue the evaporation heat absorption cycle.

[0046] It can be seen that this unit adopts a two-stage generator, two-stage evaporator, two-stage absorber and single-stage condenser arranged in an upper and lower structure, which can produce a larger inlet and outlet water temperature difference for heating water or cooling water and reduce the unit area.

[0047] Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the scope defined by the claims.

Claims

1. A high-efficiency hot water type lithium bromide absorption unit with an upper and lower structural arrangement, characterized in that: The evaporator, absorber and generator all adopt two-stage heat exchange, and the condenser (4) adopts single-stage heat exchange. The unit mainly includes two independent solution circulation loops and a refrigerant pipeline. The first-stage generator (31) and the second-stage generator (32) are connected in series through pipelines, the second-stage evaporator (62) and the first-stage evaporator (61) are connected in series through pipelines, and the first-stage absorber (51) and the second-stage absorber (52) are connected in parallel through pipelines and then connected in series with the condenser (4). The condenser (4) is arranged at the uppermost part of the unit; the first-stage generator (31) and the second-stage generator (32) are arranged on the left and right, forming an upper-lower arrangement structure with the condenser (4); the condenser (4) is respectively connected to the vacuum sides of the first-stage generator (31) and the second-stage generator (32); the first-stage absorber (51) and the second-stage absorber (52) are arranged in parallel at the lowermost part of the unit; the first-stage evaporator (61) and the first-stage absorber (51) are arranged up and down, and the vacuum sides are connected; the second-stage evaporator (62) and the second-stage absorber (52) are arranged up and down, and the vacuum sides are connected.

2. The unit according to claim 1, characterized in that: The solution circulation loop is divided into a first-stage solution circulation loop and a second-stage solution circulation loop. The first-stage solution circulation loop mainly comprises a first-stage generator (31), a first-stage solution heat exchanger (71), a first-stage solution pump (11), a first-stage absorber (51), and pipelines; and the second-stage solution circulation loop mainly comprises a second-stage generator (32), a second-stage solution heat exchanger (72), a second-stage solution pump (12), a second-stage absorber (52), and pipelines.

3. The unit according to claim 2, characterized in that: The first-stage solution circulation loop and the second-stage solution circulation loop are connected in parallel.

4. The unit according to claim 1, characterized in that: The condenser (4) is connected to the first-stage evaporator (61) through a pipeline, and the second-stage evaporator (62) is connected to the first-stage evaporator (61) and the refrigerant pump (2) through pipelines, thereby forming a refrigerant pipeline.

5. The unit according to claim 4, characterized in that: The refrigerant pump (2) and the first-stage evaporator (61) and the second-stage evaporator (62) are connected in parallel to form a refrigerant water spray pipeline (15).

6. The unit according to claim 1, characterized in that: A first-stage generating-condensing liquid baffle (81) is arranged between the condenser (4) and the first-stage generator (31), a second-stage generating-condensing liquid baffle (82) is arranged between the condenser (4) and the second-stage generator (32), a first-stage evaporating-absorbing liquid baffle (91) is arranged between the first-stage evaporator (61) and the first-stage absorber (51), and a second-stage evaporating-absorbing liquid baffle (92) is arranged between the second-stage evaporator (62) and the second-stage absorber (52).

7. The unit according to claim 1, characterized in that: The first-stage generator (31) and the second-stage generator (32) are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate; the first-stage absorber (51) and the second-stage absorber (52) are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate; the first-stage evaporator (61) and the second-stage evaporator (62) are arranged on the left and right, and are separated into two independent spaces by installing a vertical partition plate.

8. The unit according to claim 1, characterized in that: The condenser (4), the first-stage evaporator (61), and the second-stage evaporator (62) are all provided with a refrigerant tray at the bottom; and the first-stage generator (31), the second-stage generator (32), the first-stage absorber (51), and the second-stage absorber (52) are all provided with a solution tray at the bottom.

9. The unit according to claim 1, characterized in that: The first-stage generator (31), the second-stage generator (32), the first-stage absorber (51), the second-stage absorber (52), the first-stage evaporator (61), the second-stage evaporator (62) and the condenser (4) are each a heat exchange chamber, and a plurality of rows of heat exchange tube bundles are installed in each heat exchange chamber, and each heat exchange tube bundle is composed of a plurality of heat exchange tubes placed horizontally.

10. The unit according to claim 1, characterized in that: Spray devices are provided above the heat exchange tubes of the first-stage generator (31), the second-stage generator (32), the first-stage absorber (51), the second-stage absorber (52), the first-stage evaporator (61) and the second-stage evaporator (62).

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