A cold energy power generation process based on a water chilling unit

Abstract

The application provides a cold energy power generation process based on a water chiller, and relates to the technical field of waste energy recycling of water chillers. According to the existing water chiller and cold energy power generation process, the solution of coupling the water chiller and the cold energy power generation process is proposed to solve the problems of direct discharge of waste heat at the condenser end and low comprehensive energy utilization rate. In the application, the power generation working medium is in a closed cycle, and sequentially exchanges heat with the refrigerant in the evaporator, the chilled water return water and the waste heat in the condenser, and then enters the cold energy power generation unit to do work and generate power, and then repeats the above heat exchange process. The chilled water sequentially exchanges heat with the power generation working medium and indoor air. The application can utilize the cold energy of the evaporator, recycle the waste heat of the chilled water return water and the waste heat of the condenser to generate power without affecting the refrigeration effect of the water chiller, realize the efficient utilization of energy, improve the comprehensive energy efficiency level of the water chiller, and is suitable for energy-saving reconstruction scenes of various water chillers.

Description

Technical Field

[0001] This invention relates to the field of waste energy recovery and utilization technology of chiller units, and in particular to a process flow for cold energy power generation based on chiller units. Background Technology

[0002] Chillers are the core equipment of centralized air conditioning systems, widely used in commercial buildings, industrial plants, data centers, and other places. They transfer heat through the phase change cycle of refrigerant, providing a stable cooling source for the indoor environment. The refrigeration cycle of existing chiller units typically includes four core components: evaporator, compressor, condenser, and expansion valve. After the refrigerant is throttled and cooled by the expansion valve, it absorbs heat from the chilled water and evaporates into a gaseous state in the evaporator. Subsequently, it is compressed by the compressor into a high-temperature, high-pressure gaseous refrigerant, which enters the condenser to release heat to the environment and condenses into a liquid state. The liquid refrigerant is then throttled again by the expansion valve, completing the cycle.

[0003] However, the existing operating mode of chiller units has obvious energy waste problems: Firstly, the low-temperature cold energy of the refrigerant at the evaporator end is only used to cool the chilled water and is not further utilized in a cascade manner, resulting in low cold energy utilization efficiency. Secondly, the high-temperature waste heat emitted from the condenser end is directly released into the environment, which not only wastes energy but also exacerbates the local heat island effect. This is especially true during the summer when the air conditioner is running at high load, when the condenser has a large heat dissipation load and the waste heat emission problem is more prominent.

[0004] Current energy-saving retrofit technologies for chiller units mainly focus on improving compressor efficiency and optimizing fan operation strategies, with limited research on the joint recovery and utilization of evaporator cooling energy and condenser waste heat.

[0005] Existing cold energy power generation technologies mostly rely on low-temperature cold sources such as LNG (liquefied natural gas), or only use a single cold / heat source for power generation, without designing a closed-loop process suitable for the cold-heat cascade characteristics of chiller units; some retrofit solutions also have problems affecting the normal cooling effect of chiller units and poor operational stability, and cannot achieve synergistic optimization of cold energy recovery and indoor cooling.

[0006] Therefore, in view of the shortcomings of existing technologies, there is an urgent need for a cold energy power generation process adapted to the operating characteristics of chiller units, which can utilize the cold energy of the evaporator in stages and recover the residual temperature of the chilled water return and the waste heat of the condenser without affecting the indoor cooling effect, so as to achieve efficient energy utilization and improve the overall energy efficiency of the chiller units. Summary of the Invention

[0007] In view of this, the present invention provides a cold energy power generation process based on a chiller unit to solve the problems of low cold energy utilization rate at the evaporator end, direct discharge and waste of residual heat from chilled water return and condenser waste heat, and low overall system energy efficiency during the operation of existing chiller units.

[0008] The technical solution proposed in this invention is: a cold energy power generation process based on a chiller unit, wherein the chiller unit includes an evaporator, a compressor, a condenser and an expansion valve, and the refrigerant flows sequentially through the expansion valve, evaporator, compressor and condenser to form a refrigeration cycle, and the chilled water circulates between the indoor pipe network and the evaporator; The process flow adopts a closed-loop circulation of the power generation working fluid, and specifically includes the following steps: S1 Cold Energy Liquefaction: After the refrigerant expands, cools, and depressurizes through the expansion valve, it exchanges heat with the power generation working fluid in the evaporator, and the power generation working fluid releases heat and liquefies. S2 working fluid delivery: After being buffered and stored, the liquefied working fluid is pressurized and delivered by the working fluid circulation pump. S3 Level 1 Heating: The pressurized liquid power generation fluid exchanges heat with the high-temperature chilled water returned from the indoor pipe network in the power generation fluid heat exchanger. The power generation fluid absorbs heat and heats up, while the chilled water releases heat and cools down before entering the indoor pipe network. S4 Second-stage heating and pressurization: The power generation medium, after being heated in the first stage, enters the coil installed in the condenser of the chiller unit and exchanges heat with the hot airflow formed by the condenser cooling fan. The power generation medium is heated and pressurized to become a high-pressure gas. S5 power generation: The high-pressure gaseous power generation medium enters the cold energy generator set after being stabilized, driving the generator set to generate power; S6 Circulation: The low-pressure gaseous working fluid used for power generation after doing work is discharged from the outlet of the cold energy generator set and re-enters the evaporator to exchange heat with the refrigerant, repeating the above steps S1 to S5.

[0009] Further, in step S1, the refrigerant is a low-temperature, low-pressure liquid refrigerant, which absorbs heat from the gaseous power generation medium in the evaporator and evaporates into a gaseous state, and then enters the compressor of the chiller unit for compression; the gaseous power generation medium releases its cooling capacity and condenses into a liquid power generation medium.

[0010] Furthermore, in step S2, the liquefied power generation medium first enters the liquid power generation medium buffer tank for storage. The liquid power generation medium buffer tank also realizes the system's cold storage function to smooth out fluctuations in the power generation medium flow rate.

[0011] Furthermore, the circulating pump for the power generation medium adopts a variable frequency control mode, which collects the pressure signal at the front end of the cold energy generator set in real time, and dynamically adjusts the delivery flow rate and output pressure of the power generation medium according to the pressure signal to maintain the stable intake pressure of the cold energy generator set.

[0012] Furthermore, in step S3, the heat exchanger is a shell-and-tube heat exchanger, with chilled water flowing through the shell side and the power generation medium flowing through the tube side; the return temperature of the chilled water is 12-15℃, and the inlet temperature is 7-10℃, which meets the indoor cooling requirements.

[0013] Furthermore, in step S4, the condenser coil adopts a spiral coil structure and is arranged along the air outlet direction of the condenser cooling fan; the air outlet temperature of the condenser cooling fan is 35-45℃, and the power generation working fluid is heated in the coil, with the temperature rising to 30-40℃ and the pressure rising to 0.8-1.2MPa.

[0014] Furthermore, in step S5, the high-pressure gaseous power generation medium after being heated and pressurized first enters the gaseous power generation medium buffer tank for pressure stabilization. The volume of the gaseous power generation medium buffer tank is 2-3 times the gas intake of the cold energy generator set per minute, which is used to buffer the instantaneous gas consumption fluctuations of the cold energy generator set.

[0015] Furthermore, the cold energy generator set is a screw-type expander generator set with a power generation efficiency of not less than 25%; the pressure of the working fluid after power generation drops to 0.2-0.3MPa and the temperature drops to 10-15℃.

[0016] Furthermore, a bypass pipeline is provided between the outlet of the heat exchanger and the inlet of the evaporator, and an electric control valve is installed on the bypass pipeline; when the cold energy generator set fails or stops running, the electric control valve automatically opens, and the power generation medium enters the evaporator directly through the bypass pipeline to maintain the continuity of the power generation medium circulation.

[0017] Furthermore, the outlet of the power generation working fluid circulation pump is equipped with a return pipeline, the other end of which is connected to the liquid power generation working fluid buffer tank. A check valve and a regulating valve are installed on the return pipeline. During the startup phase of the power generation working fluid circulation pump, the regulating valve is opened, and the liquid power generation working fluid flows back to the liquid power generation working fluid buffer tank through the return pipeline, realizing the no-load startup of the circulation pump. After the system pressure stabilizes, the regulating valve is gradually closed.

[0018] The present invention provides a cold energy power generation process based on a chiller unit, which has the following beneficial effects: In use, this invention adds a closed-loop power generation medium to the existing refrigeration cycle of the chiller unit, utilizing the cold energy at the evaporator end, recovering the residual temperature of the chilled water return, and the heat dissipation energy at the condenser end in stages, thereby achieving efficient energy utilization and significantly improving the overall energy efficiency of the chiller unit. At the same time, the installation of buffer tanks, variable frequency pumps, bypass pipelines, and return pipelines ensures the stability and safety of the system operation without affecting the original indoor cooling effect of the chiller unit, combining energy saving and practicality. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0020] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0021] In the attached diagram; Figure 1 This is a flow chart of the working fluid circulation process for the cold energy power generation technology of the present invention; Figure 2 This is a schematic diagram of the condenser coil structure and hot airflow heat exchange. Figure 3 This is a control logic diagram of the cold energy power generation process of the present invention.

[0022] List of reference numerals 1. Evaporator; 2. Liquid working fluid buffer tank; 3. Working fluid circulation pump; 4. Working fluid heat exchanger; 5. Condenser cooling fan; 6. Condenser coil; 7. Gaseous working fluid buffer tank; 8. Cold energy generator set. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the described embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is based on an air-cooled chiller unit. Water-cooled chiller units can be substituted with equivalent ones according to this embodiment, and all such substitutions fall within the protection scope of the present invention.

[0025] This embodiment provides a cold energy power generation process based on a chiller unit. Without changing the original core structure of the chiller unit's refrigeration cycle or affecting the normal indoor cooling effect, an independent closed-loop power generation system is added. This system utilizes the low-temperature cold energy at the evaporator end, recovers the residual temperature of the indoor chilled water return, and the waste heat at the condenser end in stages, thereby achieving coupled operation of the chiller unit's refrigeration and cold energy power generation, and solving the problem of low comprehensive energy utilization rate of existing chiller units.

[0026] I. Overall System Structure: The system used in this embodiment includes two parts: the original basic components of the chiller unit and the newly added power generation working fluid circulation components. The original basic components of the chiller unit are: evaporator 1, compressor, condenser, expansion valve, indoor chilled water piping network, and condenser cooling fan 5. The refrigerant flows sequentially through the expansion valve, evaporator 1, compressor, and condenser to form a closed refrigeration cycle; the chilled water circulates between the indoor piping network and evaporator 1 and the heat exchanger for the power generation medium, realizing the transfer of indoor heat.

[0027] The newly added power generation working fluid circulation components include: liquid power generation working fluid buffer tank 2, power generation working fluid circulation pump 3, power generation working fluid heat exchanger 4, condenser coil 6, gaseous power generation working fluid buffer tank 7, cold energy generator set 8, as well as supporting connecting pipelines, valves and frequency conversion control system.

[0028] The specific connection relationships of each component are as follows: The outlet of the power generation working fluid of evaporator 1 is connected to the top inlet of liquid power generation working fluid buffer tank 2 via a pipeline; The bottom outlet of the liquid power generation working fluid buffer tank 2 is connected to the inlet of the power generation working fluid circulation pump 3 via a pipeline; The outlet of the power generation working fluid circulation pump 3 is connected to the tube inlet of the power generation working fluid heat exchanger 4 through the main pipeline. The tube-side outlet of the power generation working fluid heat exchanger 4 is connected to the inlet of the condenser coil 6 via the main pipeline, and is also connected to the power generation working fluid inlet of the evaporator 1 via the bypass pipeline. An electric shut-off valve is installed on the bypass pipeline. The condenser coil 6 is arranged horizontally on the air outlet side of the condenser along the air outlet direction of the condenser cooling fan 5, and adopts a spiral coil structure to increase the heat exchange area. The outlet of condenser coil 6 is connected to the bottom inlet of gaseous power generation working fluid buffer tank 7 via a pipeline; The top outlet of the gaseous power generation working fluid buffer tank 7 is connected to the air inlet of the cold energy generator set 8 via a pipeline; The exhaust port of the cold energy generator set 8 is connected to the inlet of the power generation medium of the evaporator 1 through a pipeline, forming a complete closed-loop cycle of the power generation medium; The outlet of the power generation working fluid circulation pump 3 is also equipped with a return pipeline. The other end of the return pipeline is connected to the side return port of the liquid power generation working fluid buffer tank 2. A check valve and an electric regulating valve are installed in sequence on the return pipeline. The shell-side inlet of the power generation working fluid heat exchanger 4 is connected to the indoor chilled water return pipe, and the shell-side outlet is connected to the indoor chilled water inlet pipe.

[0029] II. Detailed process flow during normal operation: The cold energy power generation process in this embodiment operates synchronously with the original refrigeration cycle of the chiller unit, and is specifically divided into the following six stages: 1. Basic Refrigeration Cycle Operation Phase: The chiller unit operates normally according to its original design parameters: the ambient temperature high-pressure liquid refrigerant is throttled and depressurized by the expansion valve, becoming a low-temperature, low-pressure liquid refrigerant with a temperature of 2-5℃ and a pressure of 0.3-0.4MPa, and enters the refrigerant side of evaporator 1; in evaporator 1, the low-temperature liquid refrigerant absorbs heat and evaporates into a gaseous state, which is then drawn into the compressor and compressed into a high-temperature, high-pressure gas with a temperature of 80-90℃ and a pressure of 1.2-1.5MPa; the high-temperature, high-pressure gaseous refrigerant enters the condenser, and is cooled down to 35-40℃ by forced air cooling by the condenser cooling fan 5, becoming an ambient temperature high-pressure liquid refrigerant; the ambient temperature high-pressure liquid refrigerant is throttled and depressurized again by the expansion valve and returns to evaporator 1, completing a complete refrigeration cycle.

[0030] Meanwhile, the chilled water in the indoor pipe network absorbs heat indoors, and its temperature rises to 12-15℃. It then enters the shell side of the power generation working fluid heat exchanger 4 through the return water pipe. After heat exchange and cooling, it returns to the indoor pipe network through the inlet water pipe, continuously providing cooling for the indoor environment.

[0031] 2. Cold energy liquefaction stage of the power generation medium: The low-pressure gaseous power generation medium (pressure 0.2-0.3 MPa, temperature 10-15℃) returns after performing work and enters the power generation medium side of evaporator 1, where it undergoes countercurrent heat exchange with the low-temperature, low-pressure liquid refrigerant on the refrigerant side. During this process: The low-temperature liquid refrigerant absorbs heat from the gaseous power generation working fluid to accelerate evaporation, thereby improving the heat exchange efficiency of evaporator 1 and reducing the superheat of the compressor's suction gas. After releasing its cooling capacity, the gaseous power generation medium condenses into a liquid power generation medium at a temperature of 5-8°C. The liquid power generation medium flows out from the power generation medium outlet of evaporator 1 and enters the liquid power generation medium buffer tank 2 for storage.

[0032] In this stage, the liquid power generation working fluid buffer tank 2 not only stores the liquid power generation working fluid and smooths out flow fluctuations during system operation, but also utilizes the latent heat of phase change of the liquid power generation working fluid to achieve system cooling. When the chiller unit load decreases and there is excess cooling capacity, the excess cooling capacity is stored in the form of liquid power generation working fluid; when the chiller unit load increases and there is insufficient cooling capacity, the stored liquid power generation working fluid releases cooling capacity to stabilize power generation.

[0033] 3. Frequency conversion and pressurization transmission stage of power generation working fluid: Liquid working fluid flows out from the bottom outlet of liquid working fluid buffer tank 2 and enters working fluid circulation pump 3. Working fluid circulation pump 3 adopts variable frequency control mode. The control system collects the pressure signal of the air inlet of cold energy generator set 8 in real time, compares it with the set target pressure (0.8-1.2MPa), and dynamically adjusts the speed of working fluid circulation pump 3 through PID algorithm, thereby accurately controlling the delivery flow rate and output pressure of working fluid, maintaining the stability of air inlet pressure of cold energy generator set 8, and avoiding unstable power generation caused by pressure fluctuations.

[0034] 4. First stage of heating up the power generation medium: The pressurized liquid power generation medium enters the tube side of the power generation medium heat exchanger 4, where it undergoes countercurrent heat exchange with the high-temperature chilled water (12-15°C) in the shell side. During this process: The liquid power generation working fluid absorbs heat from the chilled water, raising its temperature to 20-25℃, completing the first stage of heating; Chilled water releases heat, lowering the temperature to 7-10℃, which meets the indoor cooling temperature requirements.

[0035] In this stage, the residual heat of the chilled water return is used to preheat the working fluid for power generation. This not only increases the initial temperature of the working fluid and reduces the heating load at the subsequent condenser end, but also reduces the temperature of the chilled water that needs to be treated by evaporator 1, thus reducing the work done by the compressor and achieving bidirectional cascade utilization of energy.

[0036] 5. Secondary stage of heating and pressurizing the power generation medium: The power generation medium, after being heated in the first stage, enters the condenser coil 6 through the main pipeline. The condenser cooling fan 5 forces the waste heat emitted by the condenser to be discharged, forming a hot airflow at a temperature of 35-45℃. The power generation medium fully exchanges heat with the hot airflow in the spiral condenser coil 6, raising its temperature to 30-40℃ and its pressure to 0.8-1.2MPa, completely transforming from a liquid state into a high-pressure gaseous power generation medium.

[0037] This stage makes full use of the waste heat that was originally directly discharged into the air by the condenser, converting it into the internal energy of the power generation medium, which greatly improves the energy utilization rate of the system.

[0038] 6. Power generation and circulation phase: The high-pressure gaseous working fluid flows out from the outlet of the condenser coil 6 and enters the gaseous working fluid buffer tank 7 for pressure stabilization. The volume of the gaseous working fluid buffer tank 7 is designed to be 2-3 times the intake air volume of the cold energy generator set 8 per minute, which can effectively absorb pressure fluctuations during system operation and provide a stable intake air source for the cold energy generator set 8.

[0039] After being stabilized, the high-pressure gaseous working fluid for power generation enters the chilled generator set 8, which drives the screw expander to rotate at high speed and generate electricity. The power generation efficiency of the chilled generator set 8 is not less than 25%, and the output power can be directly connected to the building's internal power grid to power the chiller's own pumps, fans and other equipment, or it can be connected to the public power grid.

[0040] After performing work, the low-pressure gaseous working fluid (pressure 0.2-0.3MPa, temperature 10-15℃) is discharged from the exhaust port of the cold energy generator set 8 and re-enters the working fluid side of the evaporator 1 to exchange heat with the low-temperature liquid refrigerant, repeating the above process of liquefaction, pressurization, heating and power generation to achieve continuous and stable cold energy power generation.

[0041] III. Measures to ensure the safe and stable operation of the system: This embodiment incorporates multiple safety safeguards to ensure that the normal cooling operation of the chiller unit is not affected during power generation system failures or start-up / shutdown processes: 1. Fault bypass operation mechanism: A bypass line installed between the tube-side outlet of the power generation refrigerant heat exchanger 4 and the power generation refrigerant inlet of the evaporator 1 is interlocked with the operating status of the chiller generator set 8. When the chiller generator set 8 malfunctions, requires maintenance, or is manually stopped, the control system automatically opens the electric shut-off valve on the bypass line and simultaneously closes the main electric shut-off valve at the inlet of the condenser coil 6. At this time, the power generation refrigerant flows out from the tube-side outlet of the power generation refrigerant heat exchanger 4, bypassing the condenser coil 6 and the chiller generator set 8, and directly enters the evaporator 1 through the bypass line, maintaining the continuity of the power generation refrigerant circulation without affecting the original refrigeration cycle operation of the chiller unit.

[0042] 2. No-load start mechanism for circulating pump: A return pipeline is installed at the outlet of the circulating pump 3 to enable no-load start-up of the circulating pump. During the start-up phase of the circulating pump 3, the control system first opens the electric regulating valve on the return pipeline and closes the main valve. After the circulating pump starts, the liquid power generation medium flows back to the liquid power generation medium buffer tank 2 through the return pipeline. At this time, the circulating pump is in a no-load state, with a small starting current, avoiding equipment damage caused by starting under load. After the circulating pump runs stably and the system pressure reaches the set value, the control system gradually closes the electric regulating valve on the return pipeline and simultaneously opens the main valve, allowing the power generation medium to enter the normal conveying process.

[0043] IV. Specific Application Examples: This application example uses a 100RT air-cooled chiller unit of a certain model, paired with the cold energy power generation system of this invention. The power generation medium is the environmentally friendly organic refrigerant R245fa. The main operating parameters of the system are as follows: Expansion valve outlet refrigerant: temperature 4℃, pressure 0.35MPa; Liquid working fluid for power generation at the outlet of evaporator 1: temperature 7℃, pressure 0.28MPa; The outlet pressure of the power generation working fluid circulation pump 3 is 1.0 MPa. Power generation working fluid heat exchanger 4: chilled water return temperature 14℃, inlet water temperature 9℃; Condenser cooling fan 5 outlet air temperature: 40℃; The working fluid for power generation at the outlet of condenser coil 6 is at a temperature of 36℃ and a pressure of 1.0MPa. Cold-powered generator set 8: Rated power 5kW, power generation efficiency 28%.

[0044] Continuous operation test results show that the cold energy power generation process of the present invention operates stably. Under the premise of fully meeting the indoor cooling demand, it can generate 4.2 kWh per hour. The comprehensive energy efficiency ratio (COP) of the chiller unit is 13.5% higher than that of the original system, which has significant energy-saving and economic benefits.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0046] The following points should be noted in this article: 1. The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention; other structures can refer to general designs.

[0047] 2. Where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other to obtain new embodiments.

[0048] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A chilled water power generation process based on a chiller unit, wherein the chiller unit includes an evaporator, a compressor, a condenser, and an expansion valve; refrigerant flows sequentially through the expansion valve, evaporator, compressor, and condenser to form a refrigeration cycle; chilled water circulates between the indoor piping network and the evaporator and the power generation heat exchanger; characterized in that, The cold energy power generation process adopts a closed-loop circulation of the power generation working fluid, specifically including the following steps: S1 Cold Energy Liquefaction: After the refrigerant expands, cools, and depressurizes through the expansion valve, it exchanges heat with the power generation working fluid in the evaporator, and the power generation working fluid releases heat and liquefies. S2 working fluid delivery: After being buffered and stored, the liquefied working fluid is pressurized and delivered by the working fluid circulation pump. S3 Level 1 Heating: The pressurized liquid power generation fluid exchanges heat with the high-temperature chilled water returned from the indoor pipe network in the power generation fluid heat exchanger. The power generation fluid absorbs heat and heats up, while the chilled water releases heat and cools down before entering the indoor pipe network. S4 Second-stage heating and pressurization: The power generation medium, after being heated in the first stage, enters the coil installed in the condenser of the chiller unit and exchanges heat with the hot airflow formed by the condenser cooling fan. The power generation medium is heated and pressurized to become a high-pressure gas. S5 power generation: The high-pressure gaseous power generation medium enters the cold energy generator set after being stabilized, driving the generator set to generate power; S6 Circulation: The low-pressure gaseous working fluid used for power generation after doing work is discharged from the outlet of the cold energy generator set and re-enters the evaporator to exchange heat with the refrigerant, repeating the above steps S1 to S5.

2. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, In step S1, the refrigerant is a low-temperature, low-pressure liquid refrigerant. After absorbing heat from the gaseous power generation medium in the evaporator, it evaporates into a gaseous state and then enters the compressor of the chiller unit for compression. After releasing its cooling capacity, the gaseous power generation medium condenses into a liquid power generation medium.

3. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, In step S2, the liquefied power generation medium first enters the liquid power generation medium buffer tank for storage. The liquid power generation medium buffer tank also realizes the system's cold storage function to smooth out fluctuations in the power generation medium flow rate.

4. The cold energy power generation process based on a chiller unit according to claim 3, characterized in that, The circulating pump for the power generation medium adopts a variable frequency control mode, which collects the pressure signal at the front end of the cold energy generator set in real time, and dynamically adjusts the delivery flow rate and output pressure of the power generation medium according to the pressure signal to maintain the stable intake pressure of the cold energy generator set.

5. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, In step S3, the heat exchanger is a shell-and-tube heat exchanger, with chilled water flowing through the shell side and the power generation medium flowing through the tube side; the return temperature of the chilled water is 12-15℃ and the inlet temperature is 7-10℃, which meets the indoor cooling requirements.

6. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, In step S4, the condenser coil adopts a spiral coil structure and is arranged along the air outlet direction of the condenser cooling fan; the air outlet temperature of the condenser cooling fan is 35-45℃, and the power generation working fluid is heated in the coil, with the temperature rising to 30-40℃ and the pressure rising to 0.8-1.2MPa.

7. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, In step S5, the high-pressure gaseous power generation medium after being heated and pressurized first enters the gaseous power generation medium buffer tank for pressure stabilization. The volume of the gaseous power generation medium buffer tank is 2-3 times the gas intake per minute of the cold energy generator set, which is used to buffer the instantaneous gas consumption fluctuations of the cold energy generator set.

8. The cold energy power generation process based on a chiller unit according to claim 1, characterized in that, The cold energy generator set is a screw-type expander generator set with a power generation efficiency of not less than 25%; after doing work, the pressure of the working fluid drops to 0.2-0.3MPa and the temperature drops to 10-15℃.

9. The cold energy power generation process based on a chiller unit according to any one of claims 1 to 8, characterized in that, A bypass pipeline is installed between the outlet of the heat exchanger for power generation and the inlet of the evaporator, and an electric control valve is installed on the bypass pipeline. When the cold energy generator set fails or stops operating, the electric control valve automatically opens, and the power generation medium enters the evaporator directly through the bypass pipeline to maintain the continuity of the power generation medium circulation.

10. The cold energy power generation process based on a chiller unit according to claim 4, characterized in that, The outlet of the power generation working fluid circulation pump is equipped with a return pipeline, the other end of which is connected to the liquid power generation working fluid buffer tank. A check valve and a regulating valve are installed on the return pipeline. During the start-up phase of the power generation working fluid circulation pump, the regulating valve is opened, and the liquid power generation working fluid flows back to the liquid power generation working fluid buffer tank through the return pipeline, realizing the no-load start-up of the circulation pump. After the system pressure stabilizes, the regulating valve is gradually closed.

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