CN103743150A - Absorption compression type automatic-overlapping refrigerating system and use method - Google Patents

Abstract

The invention discloses an absorption compression type self-cascading refrigeration system, which includes a generator, etc.; the generator communicates with a solution heat exchanger; the solution heat exchanger communicates with an absorber; the absorber communicates with a solution heat exchanger , the solution heat exchanger is connected to the generator; the generator is also connected to the condenser, and the condenser is connected to the gas-liquid separator; the gas-liquid separator is also connected to the evaporative condenser, and the evaporative condenser is connected to the first gas-liquid separator. The heat exchangers communicate with each other, the first gas-liquid heat exchanger communicates with the evaporator, the evaporator communicates with the first gas-liquid heat exchanger, the first gas-liquid heat exchanger communicates with the compressor; the gas-liquid separator communicates with the The evaporative condensers are communicated with each other; the compressor and the evaporative condensers are respectively communicated with the absorber.

Description

Absorption-compression self-cascading refrigeration system and method of use

technical field

The invention relates to the technical field of refrigeration and air-conditioning equipment, in particular to an absorption-compression self-cascading refrigeration system and its use method.

Background technique

The self-cascade refrigeration system uses mixed working fluids with different boiling points, through multi-stage gas-liquid separation, relying on the mutual coupling of the evaporation heat of the high-boiling point excess components and the condensation and heat release of the low-boiling point excess components to obtain a relatively high temperature. Low refrigeration evaporation temperature, and the variable temperature characteristic of the mixed working fluid can reduce the irreversible loss of the evaporator. The self-cascading refrigeration system's evaporating temperature has a smaller dependence on pressure than the usual refrigeration system, so its throttling loss and compressor pressure ratio are also small, and usually one compressor can meet the application requirements. In order to use a low-grade heat source (<200°C) to do work, the self-cascading refrigeration system can also use an absorption system to replace the compressor. The patent document with the publication number CN102759218 discloses a self-cascading low-temperature refrigerator coupled with compression and absorption. The main feature of this refrigerator is that the high-boiling point surplus working fluid absorbs the condensation heat from the low-boiling point surplus working substance at high pressure at medium pressure, and the low-boiling point surplus working substance evaporates at low pressure and is compressed to high pressure by a compressor, and then combined with The gaseous high boiling point surplus working fluid from the generator is mixed and condensed. This system can obtain a lower evaporation temperature under the condition of single-stage fractional condensation. However, the low-boiling-point surplus working fluid circulation in this system relies heavily on the work of the compressor, so it cannot make more use of low-grade heat sources. The patent application number is 200910304102.1 discloses a pressurized absorption type self-cascading absorption refrigeration cycle system, the main feature of this system is to use the high-pressure liquid coming out of the gas-liquid separator to enter the ejector and eject it from the evaporator The low-pressure steam has a certain boosting effect on the low-pressure steam, but the ejector is a device with a large irreversible loss, which has a great impact on the system efficiency.

Therefore, it is necessary to provide an absorption-compression self-cascading refrigeration system that has higher efficiency, retains the flexibility of compressor boosting, reduces the dependence on compressor work, and can improve the utilization rate of low-grade energy.

Contents of the invention

The technical problem to be solved by the present invention is to provide an absorption compression self-cascading refrigeration system with a simple structure and a use method.

In order to solve the above technical problems, the present invention provides an absorption compression self-cascading refrigeration system, including a generator, a solution heat exchanger, an absorber, a solution pump, a condenser, a gas-liquid separator, an evaporative condenser, a first gas Liquid heat exchanger, evaporator and compressor; the solution outlet of the generator communicates with one end of the high-temperature solution pipeline of the solution heat exchanger, and the other end of the high-temperature solution pipeline of the solution heat exchanger communicates with the solution inlet of the absorber connected; the solution outlet of the absorber communicates with one end of the low-temperature solution pipeline of the solution heat exchanger, and the other end of the low-temperature solution pipeline of the solution heat exchanger communicates with the solution inlet of the generator; The gas outlet communicates with one end of the condensing pipe of the condenser, and the other end of the condensing pipe of the condenser communicates with the wet steam inlet of the gas-liquid separator; the gas outlet of the gas-liquid separator communicates with the high temperature of the evaporative condenser. One end of the working fluid pipeline communicates with each other, and the other end of the high-temperature working medium pipeline of the evaporating condenser communicates with one end of the high-temperature liquid pipeline of the first gas-liquid heat exchanger, and the high-temperature liquid pipeline of the first gas-liquid heat exchanger The other end communicates with one end of the evaporation pipeline of the evaporator, the other end of the evaporation pipeline of the evaporator communicates with one end of the low-temperature gas pipeline of the first gas-liquid heat exchanger, and the low-temperature gas pipeline of the first gas-liquid heat exchanger communicates with each other. The other end communicates with the gas inlet of the compressor; the solution outlet of the gas-liquid separator communicates with one end of the evaporation pipeline of the evaporation condenser; the other end of the gas outlet of the compressor and the evaporation pipeline of the evaporation condenser are respectively It communicates with the gas inlet of the absorber.

As an improvement of the absorption compression self-cascading refrigeration system of the present invention: a first throttle valve is arranged between the high-temperature solution pipeline port of the solution heat exchanger and the solution inlet of the absorber; the solution of the absorber A solution pump is provided between the outlet and the low-temperature solution pipeline port of the solution heat exchanger; a third throttle is provided between the other end of the high-temperature liquid pipeline of the first gas-liquid heat exchanger and the port of the evaporation pipeline of the evaporator Valve; a second throttling valve is set between the solution outlet of the gas-liquid separator and the port of the evaporation pipeline of the evaporation condenser.

As a further improvement of the absorption compression self-cascading refrigeration system of the present invention: a two-way valve is connected between the gas inlet of the compressor and the gas outlet of the compressor.

As a further improvement of the absorption compression self-cascading refrigeration system of the present invention: a second gas-liquid heat exchanger is arranged between the generator, the solution heat exchanger and the condenser; the low temperature of the solution heat exchanger The solution pipeline is connected to the low-temperature liquid pipeline of the second gas-liquid heat exchanger, and the low-temperature liquid pipeline of the second gas-liquid heat exchanger is connected to the solution inlet of the generator; the gas outlet of the generator is connected to the second gas-liquid exchanger. The high-temperature gas pipeline of the heater is connected, and the high-temperature gas pipeline of the second gas-liquid heat exchanger is connected with the condensation pipeline of the condenser.

As a further improvement of the absorption-compression self-cascading refrigeration system of the present invention: the working medium in the generator is a binary or more than binary non-azeotropic mixed working medium.

As a further improvement of the absorption-compression self-cascading refrigeration system of the present invention: the compressor is an inverter compressor.

A method for using an absorption compression self-cascading refrigeration system: the steps are as follows:

By heating the non-azeotropic mixture of binary or more than binary working fluid, a low-boiling point surplus gas-phase working substance I and a high-boiling point surplus liquid-phase working substance I are produced; after the low-boiling point surplus gas-phase working substance I is condensed by an external cold source, Carry out gas-liquid separation to produce low-boiling point surplus gas-phase working medium II and high-boiling point surplus liquid-phase working substance II; the low-boiling point surplus gas-phase working medium II and high-boiling point surplus liquid-phase working substance II are mutually heat-exchanged to convert the low-boiling point The excess gas-phase working medium II condenses to become liquid-phase working medium I, and the high-boiling point excess liquid-phase working medium II absorbs heat and evaporates to become gas-phase working medium I; liquid-phase working medium I undergoes the steps of exothermic cooling and endothermic evaporation to become gas-phase working Gas-phase working medium II; after heat exchange with liquid-phase working medium I, gas-phase working medium II is mixed with gas-phase working medium I to form low-boiling point surplus gas-phase working medium III; after high-boiling point surplus liquid-phase working medium I releases heat, the temperature decreases, and then mixed with gas-phase working substance I The low-boiling-point excess gas-phase working medium III is mixed and absorbed by the low-boiling point excess gas-phase working medium III to become liquid-phase working medium II; The zeotropic mixed working medium above yuan will be used for the next round of circulation.

Compared with the existing self-cascading refrigeration system, the absorption-compression self-cascading refrigeration system and the use method of the present invention have the following advantages:

1) Compared with the electric-driven compression self-cascading system, it can simultaneously use low-grade thermal energy and electric energy for joint drive, which can reduce high-grade energy consumption and increase the utilization rate of low-grade energy.

2) Compared with the heat-driven absorption self-cascading system, the frequency conversion compressor can be used to pressurize the low-pressure gas from the evaporator, which avoids multi-stage cascade, simplifies the system configuration, and makes the adjustment of the evaporation temperature easier. flexible.

3) Compared with the existing electric and thermal combined absorption compression self-cascading system, the solution absorption cycle in the present invention undertakes more driving work, thus further reducing the power consumption and pressure ratio of the compressor, and expanding the Utilization of low-grade energy. In addition, the present invention has two working modes of absorption compression and absorption, which can be switched according to the situation. For example, when the required evaporation temperature is high or the temperature of the external cold source is low, the system can work in the heat-driven absorption mode, thereby Greatly reduced high-grade power consumption.

Description of drawings

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is a kind of structural representation of absorption compression type self-cascading refrigeration system of the present invention;

Fig. 2 is another structural schematic diagram of the absorption compression self-cascading refrigeration system of the present invention.

Detailed ways

Implementation example 1, Figure 1 provides a kind of absorption compression type self-cascading refrigeration system, including generator 1, solution heat exchanger 2, absorber 4, solution pump 5, condenser 6, gas-liquid separator 7, An evaporative condenser 8, a first gas-liquid heat exchanger 11, an evaporator 13 and a compressor 14.

The solution outlet of the generator 1 communicates with one end of the high-temperature solution pipeline of the solution heat exchanger 2, and the other end of the high-temperature solution pipeline of the solution heat exchanger 2 communicates with the solution inlet of the absorber 4; the high-temperature solution pipeline of the solution heat exchanger 2 A first throttle valve 3 is arranged between the solution pipeline port and the solution inlet of the absorber 4; the solution outlet of the absorber 4 communicates with one end of the low-temperature solution pipeline of the solution heat exchanger 2, and the low-temperature solution of the solution heat exchanger 2 The other end of the pipeline communicates with the solution inlet of the generator 1; a solution pump 5 is arranged between the solution outlet of the absorber 4 and the low-temperature solution pipeline port of the solution heat exchanger 2; the gas outlet of the generator 1 is connected to the outlet of the condenser 6 One end of the condensing pipe is connected to each other, and the other end of the condensing pipe of the condenser 6 is connected to the wet steam inlet of the gas-liquid separator 7; The other end of the high-temperature working medium pipeline of the evaporating condenser 8 communicates with one end of the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11, and the other end of the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11 communicates with the evaporator One end of the evaporation pipeline of 13 communicates with each other, the other end of the evaporation pipeline of the evaporator 13 communicates with one end of the low-temperature gas pipeline of the first gas-liquid heat exchanger 11, and the other end of the low-temperature gas pipeline of the first gas-liquid heat exchanger 11 One end communicates with the gas inlet of the compressor 14; a third throttle valve 12 is arranged between the other end of the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11 and the port of the evaporation pipeline of the evaporator 13; the gas-liquid separator The solution outlet of 7 communicates with one end of the evaporation pipeline of the evaporation condenser 8; the second throttle valve 9 is arranged between the solution outlet of the gas-liquid separator 7 and the port of the evaporation pipeline of the evaporation condenser 8; The gas outlet and the other end of the evaporation pipe of the evaporation condenser 8 communicate with the gas inlet of the absorber 4 respectively.

A two-way valve 10 is connected between the gas inlet of the compressor 14 and the gas outlet of the compressor 14 .

The above-mentioned compressor 14 is an inverter compressor, which can be controlled according to the set outlet pressure. The working medium in the above-mentioned generator 1 is a binary or more than binary non-azeotropic mixed working medium, and the solution for absorbing the mixed working medium gas in the absorber 1 can only be composed of the liquid phase components of the absorbed gas itself , may also include additional third-party components that do not substantially vaporize over the operating temperature range. The mixed working fluid used can be selected from the aspects of working temperature, thermophysical properties and technical and economic indicators.

In actual use, the mixed working fluid in generator 1, the specific steps are as follows:

1. Absorption compression mode (as shown in Figure 1, the compressor 14 is on, and the two-way valve 10 is off):

1. The external heat source heats the generator 1 under high pressure, so that the mixed working medium in the generator 1 is heated and evaporated, and a low boiling point excess gas phase working medium I and a high boiling point excess liquid phase working medium I are produced;

1.1. Low boiling point excess gas phase I:

1.1.1. The low boiling point excess gas phase I flows out from the gas outlet of the generator 1, enters the condensation pipe of the condenser 6, and condenses the condensation pipe through an external cold source. The temperature of the low boiling point excess gas phase I in the condensation pipe decreases and the dryness Descends and becomes wet steam Ⅰ;

1.1.2. The wet steam I enters the gas-liquid separator 7, and the gas-liquid separator 7 separates the wet steam I from gas to liquid to produce a low-boiling-point surplus gas-phase working medium II and a high-boiling point surplus liquid-phase working medium II;

1.1.3. The low-boiling point excess gas-phase working medium II flows out from the gas outlet of the gas-liquid separator 7 and enters the condensing pipe of the evaporative condenser 8, and the low-boiling point surplus gas-phase working medium II releases heat in the condensing pipe of the evaporative condenser 8 After that, the temperature drops and condenses to become liquid-phase working substance I with the same concentration as the gas-phase working substance;

At the same time, the high-boiling-point excess liquid-phase working medium II flows out from the liquid outlet of the gas-liquid separator 7, passes through the second throttle valve 9, and the pressure drops from high pressure to medium pressure, and enters the evaporation pipeline of the evaporative condenser 8 after the temperature drops at the same time; In the evaporation pipeline of the evaporative condenser 8, after the high-boiling point surplus liquid-phase working substance II absorbs heat and evaporates (the low-boiling point surplus gas-phase working substance II releases heat in the condensing pipeline of the evaporative condenser 8, and is absorbed by the high-boiling point surplus liquid-phase working substance Ⅱ absorption), the temperature rises and becomes the gas phase working substance Ⅰ;

1.1.4. The liquid-phase working medium I enters the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11, and the temperature further decreases after heat release, and then passes through the third throttle valve 12, and the pressure decreases from high pressure to low pressure, and at the same time, after the temperature drops Enter the evaporation pipe of the evaporator 13, absorb heat and evaporate in the evaporation pipe of the evaporator 13, the temperature rises, and become the gas phase working medium II;

1.1.5. The gas-phase working medium II enters the low-temperature gas pipeline of the first gas-liquid heat exchanger 11 and absorbs heat (in step 1.1.4, the liquid-phase working medium I enters the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11 After heat release), the temperature rises further, and then enters the gas inlet of the compressor 14, is boosted from low pressure to medium pressure by the compressor 14, and finally flows out from the gas outlet of the compressor 14;

1.1.6. Gas-phase working medium I and gas-phase working medium II are mixed to form low-boiling point-rich gas-phase working medium III under medium pressure;

1.2. High boiling point excess liquid phase working medium Ⅰ:

1.2.1. The high-boiling-point excess liquid-phase working medium I flowing out from the liquid outlet of generator 1 flows into the high-temperature liquid pipeline of solution heat exchanger 2. Enter the absorber 4 after pressing;

2. The low-boiling point excess gas-phase working medium III under medium pressure enters the absorber 4, and is absorbed after being mixed with the high-boiling point excess liquid-phase working medium I flowing in from the liquid inlet of the absorber 4 to become liquid-phase working medium II. The released latent heat of absorption is taken away by the external cold source;

3. The liquid-phase working medium II flows out from the liquid outlet of the absorber 4 and enters the solution pump 5, and becomes a high-pressure liquid after being pressurized by the solution pump 5;

4. The high-pressure liquid pressurized by the solution pump 5 enters the low-temperature liquid pipeline of the solution heat exchanger 2, and the temperature rises after absorbing heat (in step 1.2. Substance I releases heat in the high-temperature liquid pipeline of the solution heat exchanger 2), and flows into the generator 1 from the liquid inlet of the generator 1.

2. When the absorption-compression self-cascading refrigeration system of the present invention works in the absorption mode (the compressor 14 is closed and the two-way valve 10 is opened), the working steps are as follows:

1. The external heat source heats the generator 1 under high pressure, so that the mixed working medium in the generator 1 is heated and evaporated, and a low boiling point excess gas phase working medium I and a high boiling point excess liquid phase working medium I are produced;

1.1. Low boiling point excess gas phase I:

1.1.1. The low boiling point excess gas phase I flows out from the gas outlet of the generator 1, enters the condensation pipe of the condenser 6, and condenses the condensation pipe through an external cold source. The temperature of the low boiling point excess gas phase I in the condensation pipe decreases and the dryness Descends and becomes wet steam Ⅰ;

1.1.2. The wet steam I enters the gas-liquid separator 7, and the gas-liquid separator 7 separates the wet steam I from gas to liquid to produce a low-boiling-point surplus gas-phase working medium II and a high-boiling point surplus liquid-phase working medium II;

1.1.3. The low-boiling point excess gas-phase working medium II flows out from the gas outlet of the gas-liquid separator 7 and enters the condensing pipe of the evaporative condenser 8, and the low-boiling point surplus gas-phase working medium II releases heat in the condensing pipe of the evaporative condenser 8 After that, the temperature drops and condenses to become liquid-phase working substance I with the same concentration as the gas-phase working substance;

At the same time, the high-boiling-point excess liquid-phase working medium II flows out from the liquid outlet of the gas-liquid separator 7, passes through the second throttle valve 9, the pressure drops from high pressure to low pressure, and enters the evaporation pipeline of the evaporation condenser 8 after the temperature drops at the same time; In the evaporation pipeline of the evaporative condenser 8, after the high-boiling point surplus liquid-phase working substance II absorbs heat and evaporates (the low-boiling point surplus gas-phase working substance II releases heat in the condensing pipeline of the evaporative condenser 8, and is absorbed by the high-boiling point surplus liquid-phase working substance II Absorption), the temperature rises, and becomes the gas phase working substance Ⅰ;

1.1.4. The liquid-phase working medium I enters the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11, and the temperature further decreases after heat release, and then passes through the third throttle valve 12, and the pressure decreases from high pressure to low pressure, and at the same time, after the temperature drops Enter the evaporation pipe of the evaporator 13, absorb heat and evaporate in the evaporation pipe of the evaporator 13, the temperature rises, and become the gas phase working medium II;

1.1.5. The gas-phase working medium II enters the low-temperature gas pipeline of the first gas-liquid heat exchanger 11 and absorbs heat (in step 1.1.4, the liquid-phase working medium I enters the high-temperature liquid pipeline of the first gas-liquid heat exchanger 11 exothermic), the temperature rises further, and then flows into the absorber 4 after passing through the two-way valve 10;

1.1.6. Gas-phase working medium I and gas-phase working medium II are mixed to form low-boiling point-rich gas-phase working medium III under low pressure;

1.2. High boiling point excess liquid phase working medium Ⅰ:

1.2.1. The high-boiling point excess liquid-phase working medium I flowing out from the liquid outlet of the generator 1 flows into the high-temperature liquid pipeline of the solution heat exchanger 2, and the temperature decreases after heat release, and then the pressure is reduced to a low pressure through the first throttle valve 3 Then enter the absorber 4;

2. The low-boiling point excess gas-phase working medium III under medium pressure enters the absorber 4, and is absorbed after being mixed with the high-boiling point excess liquid-phase working medium I flowing in from the liquid inlet of the absorber 4 to become liquid-phase working medium II. The released latent heat of absorption is taken away by the external cold source;

3. The liquid-phase working medium II flows out from the liquid outlet of the absorber 4 and enters the solution pump 5, and becomes a high-pressure liquid after being pressurized by the solution pump 5;

4. The high-pressure liquid pressurized by the solution pump 5 enters the low-temperature liquid pipeline of the solution heat exchanger 2, and the temperature rises after absorbing heat (in step 1.2. Substance I releases heat in the high-temperature liquid pipeline of the solution heat exchanger 2), and flows into the generator 1 from the liquid inlet of the generator 1.

Absorption compression working mode and absorption working mode can be switched according to actual operating conditions. When the required evaporation temperature is low or the cooling source temperature is high, the system can switch to absorption compression working mode; when the required evaporation temperature is high When the temperature of the cold source is high or the temperature of the cold source is low, the system can switch to the absorption mode of operation.

Implementation example 2, as shown in Figure 2, the system consists of generator 1, solution heat exchanger 2, first throttle valve 3, absorber 4, solution pump 5, condenser 6, gas-liquid separator 7, evaporation condenser 8, The second throttle valve 9, the two-way valve 10, the first gas-liquid heat exchanger 11, the third throttle valve 12, the evaporator 13, the compressor 14 and the second gas-liquid heat exchanger 15 are composed.

In order to reduce the heat absorption of the generator and improve the COP of the system, in Embodiment 2, the absorption compression self-cascading refrigeration system of the present invention is adopted on the basis of the configuration of Embodiment 1, and the generator 1, the solution heat exchanger 2 and the condenser 6 are provided with a second gas-liquid heat exchanger 15: that is, the low-temperature solution pipeline of the solution heat exchanger 2 is connected to the low-temperature liquid pipeline of the second gas-liquid heat exchanger 15, and the second gas The low-temperature liquid pipeline of liquid heat exchanger 15 is connected with the solution inlet of generator 1; The gas outlet of generator 1 is connected with the high-temperature gas pipeline of second gas-liquid heat exchanger 15, and the second gas-liquid heat exchanger 15 The high-temperature gas pipeline is connected with the condensation pipeline of the condenser 6 . The rest of the connections are exactly the same as in Example 1.

The difference between the workflow of this embodiment and the implementation example 1 is as follows:

1. The low-boiling-point excess gas-phase working medium flowing out from the gas outlet of the generator 1 enters the high-temperature gas pipeline of the second gas-liquid heat exchanger 15, and is exchanged with the solution in the low-temperature liquid pipeline of the second gas-liquid heat exchanger 15 at the same time. After heat release, it is partially condensed, the temperature decreases, and the dryness decreases, and then enters the condenser 6 and is further partially condensed by an external cold source in its condensation pipe, the temperature and dryness further decrease, and then enters the gas-liquid separation after becoming wet steam device 7;

2. The liquid-phase working medium flowing in from the liquid outlet of the absorber 2 is pressurized by the solution pump 5 to become a high-pressure liquid, and then enters the low-temperature liquid pipeline of the solution heat exchanger 2. After absorbing heat, the temperature rises, and then enters the second gas-liquid The temperature of the low-temperature liquid pipeline of the heat exchanger 15 rises after absorbing heat, and finally flows into the generator 1 from the liquid inlet of the generator 1 .

The rest of the work flow is exactly the same as that of Example 1.

Implementation example 2 adds the second gas-liquid heat exchanger 15, reclaims the latent heat of condensation discharged during partial condensation of the low-boiling point surplus gas phase working medium flowing out from the gas outlet of the generator, and reduces the heat consumption when heating the solution in the generator. Can improve system COP.

The calculation parameters of implementation example 1 and implementation example 2 are shown in Table 1 (for 1kg evaporator mixed refrigerant). The design conditions are: the ambient temperature is 22°C, the working fluid is R23/R134a, the maximum temperature of the required driving heat source is higher than 64.4°C, the minimum temperature of the required cooling liquid is lower than 24.2°C, the pressure of the generator is 3Mpa, and the absorber The pressure of the evaporator is 1.6Mpa, the evaporation pressure of the evaporator is 0.6Mpa, and the evaporation temperature of the refrigerant is in the range of -25.4°C to -3.9°C. The COP (defined as the ratio of the heat absorbed by evaporation to the power consumption of the compressor and the heat absorbed by the generator) calculated in Example 1 is 29.4%. The input ratio) is 23.45%; compared with implementation example 1, implementation example 2 reclaims part of the heat of the generator outlet gas-phase mixed working medium when it is partially condensed and is used to heat the solution entering the generator, so the required generator absorbs The heat is reduced, so that the COP and system exergy efficiency rise to 36.3% and 26.7%, respectively, indicating that the improvement has a certain practical effect. Under the same conditions in Table 1, compared with the compression absorption coupling absorption self-cascading refrigeration system proposed by the patent CN102759218, the present invention reduces the power consumption of the compressor to 59.5% by consuming at least 143.4kJ/kg more heat, and simultaneously compresses The machine pressure ratio is reduced from 5 to 2.67, which increases the dependence on low-grade energy and reduces the consumption of high-grade electric energy, thereby effectively realizing the original purpose of the present invention. In summary, the absorption compression self-cascading refrigeration system proposed by the present invention has higher efficiency, retains the flexibility of compressor pressurization, reduces the dependence on compressor work, and can also improve low-grade Energy utilization rate, compressor discharge temperature is low, and has good application value.

In the above implementation examples, the design parameters of the system can be reasonably determined by comprehensively considering the specific use conditions and requirements, technical and economic performance and other factors, so as to take into account the applicability and economy of the system.

Table 1 Thermodynamic calculation results of implementation example 1 and implementation example 2 (1kg evaporator mixed refrigerant)

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (7)

1. absorb compression auto-cascading refrigeration system, comprise generator (1), solution heat exchanger (2), absorber (4), solution pump (5), condenser (6), gas-liquid separator (7), evaporative condenser (8), the first gas-liquid heat-exchange (11), evaporimeter (13) and compressor (14); It is characterized in that: one end of the pyrosol pipeline of the taphole of described generator (1) and solution heat exchanger (2) is interconnected, the solution inlet port of other one end of the pyrosol pipeline of solution heat exchanger (2) and absorber (4) is interconnected;

One end of the cryogenic fluid pipeline of the taphole of described absorber (4) and solution heat exchanger (2) is interconnected, and the solution inlet port of other one end of the cryogenic fluid pipeline of described solution heat exchanger (2) and generator (1) is interconnected;

One end of the condensation pipe of the gas vent of described generator (1) and condenser (6) is interconnected, and the moist steam import of other one end of the condensation pipe of described condenser (6) and gas-liquid separator (7) is interconnected;

One end of the high temperature refrigerant pipeline of the gas vent of described gas-liquid separator (7) and evaporative condenser (8) is interconnected, one end of the high-temp liquid pipeline of other one end of the high temperature refrigerant pipeline of evaporative condenser (8) and the first gas-liquid heat-exchange (11) is interconnected, one end of the evaporation tubes of other one end of the high-temp liquid pipeline of described the first gas-liquid heat-exchange (11) and evaporimeter (13) is interconnected, one end of the cryogenic gas pipeline of other one end of the evaporation tubes of evaporimeter (13) and the first gas-liquid heat-exchange (11) is interconnected, the gas access of other one end of the cryogenic gas pipeline of the first gas-liquid heat-exchange (11) and compressor (14) is interconnected,

One end of the evaporation tubes of the taphole of described gas-liquid separator (7) and evaporative condenser (8) is interconnected;

Other one end of the evaporation tubes of the gas vent of described compressor (14) and evaporative condenser (8) is interconnected with the gas feed of absorber (4) respectively.

2. absorption compression auto-cascading refrigeration system according to claim 1, is characterized in that: between the pyrosol pipe end of described solution heat exchanger (2) and the solution inlet port of absorber (4), be provided with first throttle valve (3);

Between the cryogenic fluid pipe end of the taphole of described absorber (4) and solution heat exchanger (2), be provided with solution pump (5);

Between the port of the evaporation tubes of other one end of the high-temp liquid pipeline of described the first gas-liquid heat-exchange (11) and evaporimeter (13), be provided with the 3rd choke valve (12);

Between the port of the evaporation tubes of the taphole of described gas-liquid separator (7) and evaporative condenser (8), be provided with the second choke valve (9).

3. absorption compression auto-cascading refrigeration system according to claim 2, is characterized in that: between the gas feed of described compressor (14) and the gas vent of compressor (14), be connected with two-port valve (10).

4. absorption compression auto-cascading refrigeration system according to claim 3, is characterized in that: between described generator (1), solution heat exchanger (2) and condenser (6), be provided with the second gas-liquid heat-exchange (15);

The low-temperature liquid pipe of the cryogenic fluid pipeline of described solution heat exchanger (2) and the second gas-liquid heat-exchange (15) interconnects, and the low-temperature liquid pipe of described the second gas-liquid heat-exchange (15) is connected with the solution inlet port of generator (1);

The gas vent of generator (1) is connected with the hot-gas channel of the second gas-liquid heat-exchange (15), and the condensation pipe of the hot-gas channel of described the second gas-liquid heat-exchange (15) and condenser (6) interconnects.

5. absorption compression auto-cascading refrigeration system according to claim 4, is characterized in that: the working medium in described generator (1) is binary or non-azeotropic mixed working medium more than binary.

6. absorption compression auto-cascading refrigeration system according to claim 5, is characterized in that: described compressor (14) is frequency-changeable compressor.

7. a using method that absorbs compression auto-cascading refrigeration system, is characterized in that: step is as follows:

By heating binary or non-azeotropic mixed working medium more than binary, produce low boiling gas-phase working medium I more than needed and higher boiling liquid phase working fluid I more than needed;

Gas-phase working medium I more than needed low boiling, after the condensation of external source, is carried out to gas-liquid separation, produce low boiling gas-phase working medium II more than needed and higher boiling liquid phase working fluid II more than needed;

Heat exchange mutually between described low boiling gas-phase working medium II more than needed and higher boiling liquid phase working fluid II more than needed, becomes liquid phase working fluid I by gas-phase working medium II condensation more than needed low boiling, and higher boiling liquid phase working fluid II heat absorption more than needed evaporation becomes gas-phase working medium I;

Liquid phase working fluid I after heat release cooling and heat absorption evaporation step, becomes gas-phase working medium II successively;

Gas-phase working medium II by with the mutual heat exchange of liquid phase working fluid I after, be mixed into low boiling gas-phase working medium III more than needed with gas-phase working medium I;

After higher boiling liquid phase working fluid I heat release more than needed, temperature reduces, then mixes mutually with low boiling gas-phase working medium III more than needed, and absorbs low boiling gas-phase working medium III more than needed, becomes liquid phase working fluid II;

After the liquid phase working fluid I heat exchange more than needed of liquid phase working fluid II and higher boiling, again become binary or non-azeotropic mixed working medium more than binary, and carry out the circulation of next round.

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