A cascade refrigeration system driven by industrial condensate waste heat

Abstract

This invention discloses a cascade refrigeration system driven by industrial condensate waste heat, comprising: a first evaporator, an R134a centrifugal compressor, an evaporator-condenser, a first pressure-reducing throttling valve, an absorber, a lithium bromide solution pump, a generator, a heat exchanger, a second pressure-reducing throttling valve, a condenser, and a third pressure-reducing throttling valve. For the R134a refrigerant cycle, the cold fluid side of the first evaporator is a refrigerant flow, and the hot fluid side outlet of the first evaporator is connected to the inlet of the R134a centrifugal compressor. For the lithium bromide refrigeration cycle, the hot fluid side outlet of the evaporator-condenser is connected to the inlet of the absorber, the outlet of the absorber is connected to the inlet of the lithium bromide solution pump, the outlet of the lithium bromide solution pump is connected to the inlet of the heat exchanger, the outlet of the heat exchanger is connected to the inlet of the generator, the solution outlet of the generator is connected to the heat exchanger, the liquid phase outlet of the generator is connected to the hot fluid side inlet of the heat exchanger, and the hot fluid side outlet of the heat exchanger is connected to the second pressure-reducing throttling valve.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste heat recovery and refrigeration technology, specifically relating to a cascade refrigeration system that uses industrial condensate waste heat as a driving heat source. Background Technology

[0002] In industries such as petrochemicals and chemicals, traditional manufacturing faces pressure to transform and upgrade. The production process generates a large amount of waste heat, which is often underutilized due to its low grade. For example, some companies fail to fully recover large amounts of process condensate at around 115°C, instead directly discharging it through circulating water cooling. This not only causes serious energy waste but also reduces the overall energy efficiency of the project.

[0003] On the other hand, certain processes in industrial production (such as alkali crystallization and plastic modification) require cryogenic cold sources below 0°C (e.g., -10°C). Currently, traditional industrial cryogenic refrigeration mainly relies on electrically driven compression chillers (such as screw chillers and centrifuges). These devices not only consume enormous amounts of electricity, leading to high operating costs for enterprises, but also indirectly increase greenhouse gas emissions. Although traditional lithium bromide absorption refrigeration technology can utilize waste heat, it is limited by the physical properties of water and can usually only produce chilled water above 0°C, failing to directly meet the cryogenic refrigeration needs. Therefore, there is an urgent need for a new system that can deeply couple industrial waste heat recovery with cryogenic refrigeration requirements. Summary of the Invention

[0004] This invention provides a cascade refrigeration system driven by industrial condensate waste heat. Through an innovative cascade design, the system couples absorption refrigeration with compression refrigeration, effectively utilizing low-grade industrial waste heat to produce chilled water below -10°C.

[0005] To achieve the above objectives, the present invention provides a cascade refrigeration system driven by industrial condensate waste heat, comprising: a first evaporator (1), an R134a centrifugal compressor (2), an evaporative condenser (3), a first pressure-reducing throttling valve (4), an absorber (5), a lithium bromide solution pump (6), a generator (7), a heat exchanger (8), a second pressure-reducing throttling valve (9), a condenser (10), and a third pressure-reducing throttling valve (11), wherein: For the R134a refrigerant cycle, the cold fluid side of the first evaporator (1) is the refrigerant flow, the outlet of the hot fluid side of the first evaporator (1) is connected to the inlet of the R134a centrifugal compressor (2), the outlet of the R134a centrifugal compressor (2) is connected to the inlet of the evaporator condenser (3), the outlet of the evaporator condenser (3) is connected to the inlet of the first pressure reducing throttle valve (4), and the outlet of the first pressure reducing throttle valve (4) is connected to the inlet of the first evaporator (1). For the lithium bromide refrigeration cycle, the hot fluid side outlet of the evaporator condenser (3) is connected to the inlet of the absorber (5), the outlet of the absorber (5) is connected to the inlet of the lithium bromide solution pump (6), the outlet of the lithium bromide solution pump (6) is connected to the inlet of the heat exchanger (8), the outlet of the heat exchanger (8) is connected to the inlet of the generator (7), the solution outlet of the generator (7) is connected to the heat exchanger (8), the liquid phase outlet of the generator (7) is connected to the hot fluid side inlet of the heat exchanger (8), the hot fluid side outlet of the heat exchanger (8) is connected to the second pressure reducing throttle valve (9), the outlet of the second pressure reducing throttle valve (9) is connected to the absorber (5), the vapor outlet of the generator (7) is connected to the condenser (10), the outlet of the condenser (10) is connected to the inlet of the third pressure reducing throttle valve (11), and the outlet of the third pressure reducing throttle valve (11) is connected to the hot fluid side inlet of the evaporator condenser (3).

[0006] In one embodiment of the present invention, optionally, the evaporator condenser (3) serves as a coupling device for the R134a refrigerant cycle and the lithium bromide refrigeration cycle, with the hot fluid side inlet connected to the outlet of the R134a centrifugal compressor (2), the hot fluid side outlet connected to the inlet of the first pressure reducing throttle valve (4), the cold fluid side inlet connected to the third pressure reducing throttle valve (11), and the cold fluid side outlet connected to the inlet of the absorber (5).

[0007] In one embodiment of the present invention, optionally, in the lithium bromide refrigeration cycle, the inlet of the absorber (5) is connected to the outlet of the evaporator condenser (3), the low-pressure water vapor from the evaporator condenser (3) and the lithium bromide lean solution after being heated by the heat exchanger (8) are mixed, and the lithium bromide rich solution is output, and the outlet of the absorber (5) is connected to the inlet of the lithium bromide solution pump (6).

[0008] In one embodiment of the present invention, optionally, the heat released by the low-pressure water vapor absorbed by the lithium bromide lean solution in the absorber (5) is absorbed by external cooling water.

[0009] In one embodiment of the present invention, optionally, a lithium bromide rich solution pressurized by a lithium bromide solution pump (6) enters the cold fluid side of a heat exchanger (8), and the hot fluid side of the heat exchanger (8) is a high-temperature lithium bromide hot solution from a generator (7).

[0010] In one embodiment of the present invention, optionally, the lithium bromide rich solution in the generator (7) absorbs industrial waste heat to generate high-pressure steam and separates the high-temperature lithium bromide lean solution; the generated high-pressure steam is discharged from the steam outlet of the generator (7) to the condenser (10), and the high-temperature lithium bromide lean solution is discharged from the liquid phase outlet of the generator (7) to the hot fluid side inlet of the heat exchanger (8).

[0011] In one embodiment of the present invention, optionally, the cold fluid side of the condenser (10) is connected to external cooling water to absorb the heat released from the high-pressure water vapor from the generator (7) and condense it into saturated liquid water.

[0012] In one embodiment of the present invention, optionally, the saturated liquid water output from the condenser (10) is throttled and depressurized by the third pressure reducing valve (11) and becomes low-pressure liquid water. It enters the cold fluid side of the evaporator condenser (3) and transforms into low-pressure water vapor by absorbing the condensation heat released by the R134a refrigeration cycle. Then it enters the absorber (5) to participate in the lithium bromide absorption process.

[0013] In one embodiment of the present invention, optionally, the system achieves a cascade coupling of the lithium bromide refrigeration cycle and the R134a refrigerant cycle through an evaporator condenser (3); the system uses the waste heat of industrial condensate as the driving heat source of the generator (7), and outputs a cooling capacity of less than -10°C to the refrigerant on the cold fluid side of the first evaporator (1) of the R134a refrigeration cycle.

[0014] The cascade refrigeration system driven by industrial condensate waste heat provided by this invention uses industrial waste heat as input, reducing the energy input for industrial refrigeration. The system outputs cooling capacity below -10°C and recovers and utilizes industrial waste heat, controlling greenhouse gas emissions and additional refrigeration costs, and realizing the resource utilization of industrial waste heat. Therefore, this system has good application potential in various industrial scenarios with cooling requirements, such as alkali crystallization and plastic modification. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a cascade refrigeration system driven by industrial condensate waste heat according to an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached drawings: 1-First evaporator; 2-R134a centrifugal compressor; 3-Evaporator-condenser; 4-First pressure reducing valve; 5-Absorber; 6-Lithium bromide solution pump; 7-Generator; 8-Heat exchanger; 9-Second pressure reducing valve; 10-Condenser; 11-Third pressure reducing valve. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Figure 1 This is a schematic diagram of a cascade refrigeration system driven by industrial condensate waste heat according to an embodiment of the present invention, as shown below. Figure 1 As shown, the cascade refrigeration system driven by industrial condensate waste heat provided by the present invention includes: a first evaporator 1, an R134a centrifugal compressor 2, an evaporator-condenser 3, a first pressure-reducing throttling valve 4, an absorber 5, a lithium bromide solution pump 6, a generator 7, a heat exchanger 8, a second pressure-reducing throttling valve 9, a condenser 10, and a third pressure-reducing throttling valve 11, wherein: For the R134a refrigerant cycle, the cold fluid side of the first evaporator 1 is the refrigerant flow, the outlet of the hot fluid side of the first evaporator 1 is connected to the inlet of the R134a centrifugal compressor 2, the outlet of the R134a centrifugal compressor 2 is connected to the inlet of the evaporator-condenser 3, the outlet of the evaporator-condenser 3 is connected to the inlet of the first pressure reducing throttle valve 4, and the outlet of the first pressure reducing throttle valve 4 is connected to the inlet of the first evaporator 1. For the lithium bromide refrigeration cycle, the hot fluid side outlet of the evaporator-condenser 3 is connected to the inlet of the absorber 5, the outlet of the absorber 5 is connected to the inlet of the lithium bromide solution pump 6, the outlet of the lithium bromide solution pump 6 is connected to the inlet of the heat exchanger 8, the outlet of the heat exchanger 8 is connected to the inlet of the generator 7, the solution outlet of the generator 7 is connected to the heat exchanger 8, the liquid phase outlet of the generator 7 is connected to the hot fluid side inlet of the heat exchanger 8, the hot fluid side outlet of the heat exchanger 8 is connected to the second pressure reducing throttle valve 9, the outlet of the second pressure reducing throttle valve 9 is connected to the absorber 5, the vapor outlet of the generator 7 is connected to the condenser 10, the outlet of the condenser 10 is connected to the inlet of the third pressure reducing throttle valve 11, and the outlet of the third pressure reducing throttle valve 11 is connected to the hot fluid side inlet of the evaporator-condenser 3.

[0020] In one embodiment of the present invention, optionally, the evaporator condenser 3 serves as a coupling device for the R134a refrigerant cycle and the lithium bromide refrigeration cycle. The hot fluid side inlet is connected to the outlet of the R134a centrifugal compressor 2, the hot fluid side outlet is connected to the inlet of the first pressure reducing throttle valve 4, the cold fluid side inlet is connected to the third pressure reducing throttle valve 11, and the cold fluid side outlet is connected to the inlet of the absorber 5.

[0021] In one embodiment of the present invention, optionally, in the lithium bromide refrigeration cycle, the inlet of the absorber 5 is connected to the outlet of the evaporator condenser 3, and the low-pressure water vapor from the evaporator condenser 3 and the lithium bromide lean solution after being heated by the heat exchanger 8 are mixed to output a lithium bromide rich solution, and the outlet of the absorber 5 is connected to the inlet of the lithium bromide solution pump 6.

[0022] In one embodiment of the present invention, optionally, the heat released by the low-pressure water vapor absorbed by the lithium bromide lean solution in the absorber 5 is absorbed by external cooling water.

[0023] In one embodiment of the present invention, optionally, a lithium bromide-rich solution pressurized by a lithium bromide solution pump 6 enters the cold fluid side of a heat exchanger 8, and the hot fluid side of the heat exchanger 8 is a high-temperature lithium bromide hot solution from a generator 7.

[0024] In one embodiment of the present invention, optionally, the lithium bromide rich solution in the generator 7 absorbs industrial waste heat to generate high-pressure steam and separates the high-temperature lithium bromide lean solution; the generated high-pressure steam is discharged from the steam outlet of the generator 7 to the condenser 10, and the high-temperature lithium bromide lean solution is discharged from the liquid phase outlet of the generator 7 to the hot fluid side inlet of the heat exchanger 8.

[0025] In one embodiment of the present invention, optionally, the cold fluid side of the condenser 10 is connected to external cooling water to absorb the heat released from the high-pressure water vapor from the generator 7 and condense it into saturated liquid water.

[0026] In one embodiment of the present invention, optionally, the saturated liquid water output from the condenser 10 is throttled and depressurized by the third pressure reducing valve 11, becoming low-pressure liquid water, and enters the cold fluid side of the evaporator condenser 3. It then absorbs the condensation heat released by the R134a refrigeration cycle and transforms into low-pressure water vapor, which then enters the absorber 5 to participate in the lithium bromide absorption process.

[0027] In one embodiment of the present invention, optionally, the system achieves a cascade coupling of the lithium bromide refrigeration cycle and the R134a refrigerant cycle through the evaporator condenser 3; the system uses the waste heat of industrial condensate as the driving heat source of the generator 7, and outputs a cooling capacity of less than -10°C to the refrigerant on the cold fluid side of the first evaporator 1 of the R134a refrigeration cycle.

[0028] The unit operates in a cycle process that is a coupling of lithium bromide absorption refrigeration cycle and R134a compression refrigeration cycle.

[0029] R134a compression refrigeration cycle: Low-pressure liquid R134a refrigerant absorbs heat from the refrigerant in the pipeline and evaporates in the first evaporator 1, causing the refrigerant temperature to drop (e.g., to around -5°C to -10°C), thus providing cooling capacity for process production. The resulting low-pressure R134a vapor enters the R134a centrifugal compressor 2, where it is pressurized and heated to become high-temperature, high-pressure R134a vapor, which then enters the evaporator-condenser 3. In the evaporator-condenser 3, the high-temperature, high-pressure R134a vapor releases heat to the low-pressure liquid water on the lithium bromide cycle side and condenses itself into high-pressure liquid R134a. This high-pressure liquid is then depressurized and throttled by the first pressure-reducing valve 4 before returning to the first evaporator 1, completing the reciprocating cycle of the organic working fluid.

[0030] The lithium bromide absorption refrigeration cycle includes water circulation and solution circulation.

[0031] Water circulation: In the evaporator condenser 3, low-pressure liquid water from the third pressure reducing valve 11 absorbs the heat released by the condensation of R134a and vaporizes into low-pressure water vapor. This low-pressure water vapor enters the absorber 5 and is absorbed by the lithium bromide lean solution sprayed from the generator 7. The heat generated during the absorption process is carried away by the cooling water flowing through the absorber 5.

[0032] Solution circulation: The lithium bromide rich solution, which has absorbed moisture in absorber 5, is drawn out and pressurized by lithium bromide solution pump 6. As it flows through heat exchanger 8, it exchanges heat with the high-temperature lean solution from generator 7 to raise its temperature. The heated rich solution then enters generator 7, where it boils under the heating of industrial waste heat (such as process hot condensate). Most of the low-boiling-point water in the solution is desorbed and separated, forming high-pressure steam. At the same time, the solution itself is concentrated into a lean solution with lower water content.

[0033] The high-temperature lean solution is cooled by heat exchanger 8, and then depressurized by the second pressure-reducing throttling valve 9 before returning to absorber 5 to continue absorbing water vapor. Meanwhile, the high-pressure water vapor released from generator 7 enters condenser 10, where it is condensed into saturated liquid water by cooling water. Subsequently, it is depressurized and expanded into low-pressure liquid water by the third pressure-reducing throttling valve 11, and then re-enters evaporator condenser 3 to absorb heat and evaporate, completing the entire cycle of solution and water.

[0034] When the cascade refrigeration system driven by industrial condensate waste heat provided by this invention starts up, it prioritizes the operation of a lithium bromide absorption refrigeration cycle to establish a basic cold source. First, the cooling water connecting the absorber 5 and the condenser 10 is circulated. Then, the lithium bromide solution pump 6 is started, and industrial condensate waste heat is introduced into the generator 7. As the water in the generator 7 is continuously desorbed and condensed in the condenser 10, a solution concentration difference and vapor-water circulation are gradually established within the system. Liquid water, after being throttled and depressurized by the third pressure-reducing valve 11, enters the evaporator-condenser 3, where it begins to vaporize and absorb heat on the cold fluid side (water side), thereby gradually reducing the temperature and pressure within the evaporator-condenser 3. When the temperature and pressure within the evaporator-condenser 3 decrease and are maintained at a preset low pressure and low temperature level (0.9 MPa, 5°C), the system establishes an initial cold source for compression-type circulation heat dissipation, at which point it enters the next startup stage.

[0035] Once the cold source conditions for the evaporator-condenser 3 are met, the refrigerant circulation on the first evaporator 1 side is started, followed by the activation of the R134a centrifugal compressor 2. At this time, the R134a vapor is pressurized and heated by the R134a centrifugal compressor 2 and discharged into the evaporator-condenser 3. The high-temperature, high-pressure R134a gas releases a large amount of condensation heat on the hot fluid side of the evaporator-condenser 3, which is rapidly absorbed by the low-pressure liquid water on the cold fluid side and vaporized. When the heat discharged from the R134a circulation to the evaporator-condenser 3 reaches a dynamic equilibrium with the heat absorbed by the lithium bromide circulation in the evaporator-condenser 3, and the refrigerant temperature output from the first evaporator 1 stabilizes at the set low-temperature target value (e.g., -5℃ to -10℃), the entire cascade hybrid refrigeration system enters a coupled thermal equilibrium state, achieving steady-state, high-efficiency operation of the system.

[0036] In the above specific implementation, the entire system is mainly controlled by PLC, which can automatically adjust the heat source according to the outlet temperature of lean solution, and stabilize the solution circulation volume through frequency conversion control of solution pump, thus ensuring the stability of the cold source in continuous chemical production.

[0037] The cascade refrigeration system driven by industrial condensate waste heat provided by this invention uses industrial waste heat as input, reducing the energy input for industrial refrigeration. The system outputs cooling capacity below -10°C and recovers and utilizes industrial waste heat, controlling greenhouse gas emissions and additional refrigeration costs, and realizing the resource utilization of industrial waste heat. Therefore, this system has good application potential in various industrial scenarios with cooling requirements, such as alkali crystallization and plastic modification.

[0038] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0039] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cascade refrigeration system driven by industrial condensate waste heat, characterized in that, include: The system comprises: a first evaporator (1), an R134a centrifugal compressor (2), an evaporative condenser (3), a first pressure-reducing throttling valve (4), an absorber (5), a lithium bromide solution pump (6), a generator (7), a heat exchanger (8), a second pressure-reducing throttling valve (9), a condenser (10), and a third pressure-reducing throttling valve (11), wherein: For the R134a refrigerant cycle, the cold fluid side of the first evaporator (1) is the refrigerant flow, the outlet of the hot fluid side of the first evaporator (1) is connected to the inlet of the R134a centrifugal compressor (2), the outlet of the R134a centrifugal compressor (2) is connected to the inlet of the evaporator condenser (3), the outlet of the evaporator condenser (3) is connected to the inlet of the first pressure reducing throttle valve (4), and the outlet of the first pressure reducing throttle valve (4) is connected to the inlet of the first evaporator (1). For the lithium bromide refrigeration cycle, the hot fluid side outlet of the evaporator condenser (3) is connected to the inlet of the absorber (5), the outlet of the absorber (5) is connected to the inlet of the lithium bromide solution pump (6), the outlet of the lithium bromide solution pump (6) is connected to the inlet of the heat exchanger (8), the outlet of the heat exchanger (8) is connected to the inlet of the generator (7), the solution outlet of the generator (7) is connected to the heat exchanger (8), the liquid phase outlet of the generator (7) is connected to the hot fluid side inlet of the heat exchanger (8), the hot fluid side outlet of the heat exchanger (8) is connected to the second pressure reducing throttle valve (9), the outlet of the second pressure reducing throttle valve (9) is connected to the absorber (5), the vapor outlet of the generator (7) is connected to the condenser (10), the outlet of the condenser (10) is connected to the inlet of the third pressure reducing throttle valve (11), and the outlet of the third pressure reducing throttle valve (11) is connected to the hot fluid side inlet of the evaporator condenser (3).

2. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The evaporator condenser (3) serves as a coupling device for the R134a refrigerant cycle and the lithium bromide refrigeration cycle. The hot fluid side inlet is connected to the outlet of the R134a centrifugal compressor (2), the hot fluid side outlet is connected to the inlet of the first pressure reducing throttle valve (4), the cold fluid side inlet is connected to the third pressure reducing throttle valve (11), and the cold fluid side outlet is connected to the inlet of the absorber (5).

3. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, In the lithium bromide refrigeration cycle, the inlet of the absorber (5) is connected to the outlet of the evaporator-condenser (3). The low-pressure water vapor from the evaporator-condenser (3) and the lithium bromide lean solution after heat release through the heat exchanger (8) are mixed to output a lithium bromide rich solution. The outlet of the absorber (5) is connected to the inlet of the lithium bromide solution pump (6).

4. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The heat released by the lithium bromide lean solution in the absorber (5) absorbing low-pressure water vapor is absorbed by the external cooling water.

5. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The lithium bromide rich solution pressurized by the lithium bromide solution pump (6) enters the cold fluid side of the heat exchanger (8), and the hot fluid side of the heat exchanger (8) is the high-temperature lithium bromide hot solution from the generator (7).

6. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The lithium bromide rich solution in the generator (7) absorbs industrial waste heat to generate high-pressure steam and separates the high-temperature lithium bromide lean solution; the generated high-pressure steam is discharged from the steam outlet of the generator (7) to the condenser (10), and the high-temperature lithium bromide lean solution is discharged from the liquid phase outlet of the generator (7) to the hot fluid side inlet of the heat exchanger (8).

7. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The cold fluid side of the condenser (10) is connected to external cooling water to absorb the heat released from the high-pressure water vapor from the generator (7) and condense it into saturated liquid water.

8. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The saturated liquid water output from the condenser (10) is reduced in pressure by the third pressure reducing valve (11) and becomes low-pressure liquid water. It enters the cold fluid side of the evaporator condenser (3) and transforms into low-pressure water vapor by absorbing the condensation heat released by the R134a refrigeration cycle. Then it enters the absorber (5) to participate in the lithium bromide absorption process.

9. The cascade refrigeration system driven by industrial condensate waste heat according to claim 1, characterized in that, The system achieves a cascaded coupling of the lithium bromide refrigeration cycle and the R134a refrigerant cycle through the evaporator condenser (3); the system uses the waste heat of industrial condensate as the driving heat source of the generator (7), and outputs a cooling capacity of less than -10°C to the refrigerant on the cold fluid side of the first evaporator (1) of the R134a refrigeration cycle.

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