Cascade industrial water chiller

Abstract

The utility model discloses a cascade industrial water chiller which comprises a liquid storage system, a multi-stage heat exchanger, a multi-stage cooling system and a control system. The liquid storage system comprises a liquid storage tank provided with a liquid inlet and an air return port and a refrigerant pump connected with the liquid storage tank, and is used for storing and supplying a refrigerant; the multi-stage heat exchanger comprises a high-temperature-stage heat exchanger, a low-temperature-stage heat exchanger and an intermediate heat exchanger arranged between the high-temperature-stage heat exchanger and the low-temperature-stage heat exchanger, the intermediate heat exchanger is of a spiral plate type or spraying film type structure, and refrigerant thermal coupling between the high-temperature-stage heat exchanger and the low-temperature-stage heat exchanger The multi-stage cooling system comprises a high-stage compressor and a low-stage compressor which are correspondingly connected with respective heat exchangers; the control system is used for adjusting operation parameters such as compressor frequency, refrigerant pump speed and nozzle angle in real time. The heat exchanger is compact in structure and high in heat exchange efficiency, has intelligent response and energy efficiency optimization capabilities, and is suitable for industrial refrigeration occasions such as multiple temperature zones and deep cooling.

Description

Technical Field

[0001] This utility model relates to the field of chiller technology, specifically a cascade industrial chiller. Background Technology

[0002] Currently, industrial cooling equipment is widely used in applications such as electronics manufacturing, precision injection molding, chemical reactions, and low-temperature testing, providing a stable and controllable cooling environment for the production process. To meet the needs of lower temperature ranges or larger cooling loads, the industry generally adopts cascade chiller systems, which achieve efficient cooling and stable operation through the coupling of two or more compression systems.

[0003] In existing technologies, traditional cascade chillers mostly adopt a split-type structure design, where the liquid storage system, heat exchanger, compressor unit, and electrical control system are located in different parts of the frame, and the systems are connected by external pipelines. While this arrangement offers a certain degree of structural flexibility, it has the following drawbacks in actual operation:

[0004] The equipment is structurally dispersed, occupies a large area, and is complex to install and debug. Because the connections between the various system components rely on manual piping and wiring, it is prone to problems such as an increase in refrigerant leak points, inconvenient maintenance, and unstable system performance, making it difficult to meet the modern industrial demands for integrated and rapid deployment of the entire unit.

[0005] Intermediate heat exchangers suffer from low heat exchange efficiency and slow coupling response. Currently, many intermediate heat exchangers in chillers still adopt a simple shell-and-tube structure, with the internal refrigerant flow mainly being laminar. This results in a limited heat exchange area between the high-temperature and low-temperature refrigerants, leading to low heat transfer efficiency. Especially in scenarios with unbalanced heating and cooling loads or rapid load changes, heat exchange lag or increased energy consumption are likely to occur.

[0006] Uneven refrigerant distribution and obvious local heat exchange dead zones. Some heat exchange structures have not fully optimized the liquid film distribution path and lack turbulence or liquid film coverage enhancement structures, resulting in refrigerant accumulation or dry zones on the condenser tube surface, which further affects heat exchange stability and the overall COP value of the system.

[0007] Therefore, there is an urgent need to provide a new type of cascade industrial chiller system that is compact, has high heat exchange efficiency, and is highly adaptable, in order to solve the problems of dispersed structure, lag in heat exchange, and low energy efficiency in the existing technology. Utility Model Content

[0008] This utility model relates to an industrial refrigeration equipment, specifically a cascade industrial chiller, which is suitable for industrial scenarios requiring stable and efficient cooling of multiple temperature zones or deep low temperature regions. It features strong structural integration, high heat exchange efficiency, and excellent intelligent control capabilities.

[0009] To address the technical problems of existing chillers, such as dispersed structure, low heat exchange efficiency, and slow response, this utility model proposes a modularly integrated cascade chiller with a two-stage compression and intermediate heat exchange coupling mechanism. Its main structure and technical solution are as follows:

[0010] A cascade industrial chiller, comprising:

[0011] The liquid storage system includes a liquid storage tank with a refrigerant inlet and a refrigerant return outlet, and a refrigerant pump connected thereto, for storing and transporting refrigerant;

[0012] A multi-stage heat exchanger includes a high-temperature stage heat exchanger, a low-temperature stage heat exchanger, and an intermediate heat exchanger disposed therebetween, wherein the intermediate heat exchanger is used to realize heat exchange between the high- and low-temperature stage refrigerants.

[0013] A multi-stage cooling system includes a first compression stage and a second compression stage. The first compression stage is connected to the high-temperature stage heat exchanger, and the second compression stage is connected to the low-temperature stage heat exchanger. The first compression stage and the second compression stage are thermally coupled through the intermediate heat exchanger.

[0014] The control system is used to regulate the compressor's start-up and shutdown, refrigerant flow, and heat exchange process.

[0015] Technical benefits: This structure highly integrates liquid storage, compression, heat exchange and control systems, effectively improving the refrigeration efficiency and operational stability of chillers, and is suitable for deep cryogenic conditions or high-load process cooling scenarios.

[0016] In a preferred embodiment, this invention can be further configured as follows: the intermediate heat exchanger is a spiral plate or spray film structure, equipped with refrigerant atomization or liquid film heat exchange functions; the liquid storage tank in the liquid storage system is provided with an insulation layer and a liquid level detection component; each stage compressor in the multi-stage cooling system is equipped with a filter, a check valve, and an electronic expansion valve at its inlet and outlet to achieve graded control. By strengthening the intermediate heat exchange structure and refrigerant paths at each stage, the efficiency of heat and cold coupling is improved, energy consumption is reduced, and the system's adaptability is enhanced.

[0017] In a preferred embodiment, this invention can be further configured such that: the intermediate heat exchanger is equipped with a spray assembly, which includes several adjustable-angle nozzles for atomizing the high-temperature refrigerant into a liquid film distributed on the surface of the condenser tubes; the intermediate heat exchanger is also equipped with a spiral turbulence structure to increase the degree of heat transfer turbulence. The synergistic effect of the spray-type liquid film and the spiral turbulence structure significantly improves the heat transfer efficiency of the intermediate condensation zone, enhances the uniformity of refrigerant distribution, and results in a faster response speed.

[0018] In a preferred embodiment, this invention can be further configured such that the refrigerant pump connected to the liquid storage tank is frequency-controlled by the control system based on the liquid level signal of the liquid storage tank and the compressor load status, so as to achieve on-demand refrigerant supply. The frequency-controlled pump, combined with intelligent feedback control, enables dynamic adjustment of refrigerant flow, reducing system power consumption and improving the sensitivity of cooling response.

[0019] In a preferred embodiment, this invention can be further configured such that the control system includes a temperature scheduling module, used to dynamically adjust the operating frequency and expansion valve opening of the high-temperature stage and low-temperature stage compressors based on the temperature difference between the two sides of the intermediate heat exchanger, thereby achieving balanced regulation of the cooling capacity output of the cascade stage. Based on the closed-loop temperature difference scheduling control logic, dynamic energy balance can be achieved at each stage of the system, improving refrigeration efficiency and preventing overload on the hot and cold sides.

[0020] In a preferred embodiment, this invention can be further configured such that the spray nozzles in the spray assembly are mounted on a rotating shaft, and the rotating shaft is linked to a micro-motor located outside the intermediate heat exchanger, so as to automatically adjust the spray angle of the nozzles according to the internal temperature gradient of the heat exchanger. This achieves dynamic angle optimization of liquid film spraying, ensuring that the high-temperature refrigerant can cover key areas of the heat exchange surface and effectively eliminate condensation dead zones.

[0021] In a preferred embodiment, this invention can be further configured such that the liquid storage system is equipped with a refrigerant bypass pipeline and an electromagnetic switching valve. When the liquid level in the storage tank is lower than a preset threshold, the control system automatically switches to the bypass path to prevent the pump from running dry and being damaged. This improves the safety of the system under abnormal conditions, ensures the continuity of refrigerant circulation, and extends the equipment life.

[0022] In a preferred embodiment, this invention can be further configured such that: the intermediate heat exchanger is equipped with multiple sets of parallel condenser tubes, the condenser tube area is divided into a high-load zone and a low-load zone, and the control system automatically adjusts the atomizing nozzle flow rate and spraying time of each zone according to the current heat exchange efficiency. The combination of zoned heat exchange and spray control allows for intelligent allocation of refrigerant energy based on operating conditions, improving overall heat exchange performance and reducing system energy consumption.

[0023] The beneficial effects achieved by this utility model are as follows:

[0024] 1. In this utility model, a compact and fully functional cascade industrial chiller system is constructed by modularly integrating the liquid storage system, multi-stage heat exchanger, multi-stage cooling system, and control system into one unit. This structure can adapt to the high-load, low-temperature cooling requirements of different industrial applications, improving the system's versatility and installation flexibility.

[0025] 2. In this utility model, the intermediate heat exchanger is designed with a spiral plate or spray film structure, combined with an adjustable angle nozzle and spiral baffle design, which can significantly enhance the coverage of the refrigerant liquid film and the disturbance effect on the heat exchange surface, effectively improve the heat exchange efficiency between high and low temperature stages, reduce energy consumption, and achieve a higher COP ratio. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present utility model;

[0027] Figure 2 This is a schematic diagram of the connection structure of a multi-stage heat exchanger according to an embodiment of the present invention.

[0028] Figure label:

[0029] 100. Liquid storage system; 200. Multistage heat exchanger; 300. Multistage cooling system; 400. Control system; 210. High-temperature stage heat exchanger; 220. Low-temperature stage heat exchanger; 230. Intermediate heat exchanger. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0031] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0032] The following is in conjunction with the appendix Figures 1-2 This invention describes a cascade industrial chiller provided by some embodiments of the present invention.

[0033] Example 1:

[0034] This embodiment provides a cascade industrial chiller, the overall structure of which includes:

[0035] The liquid storage system 100 includes a liquid storage tank, which is a horizontal, closed cylindrical structure. The upper part of the tank has a refrigerant inlet and a refrigerant return port, and the lower part is connected to a refrigerant pump via a pipeline. The refrigerant pump is preferably a variable frequency drive pump, with its output frequency regulated by a control system.

[0036] Technical benefits: The liquid storage tank enables stable storage and gas-liquid separation of the refrigerant, while the refrigerant pump, in conjunction with the liquid level signal feedback, enables on-demand liquid supply, effectively reducing the risk of pump idling and refrigerant pulsation fluctuations.

[0037] The multi-stage heat exchanger 200 includes a high-temperature stage heat exchanger 210, a low-temperature stage heat exchanger 220, and an intermediate heat exchanger 230 disposed therebetween. The high-temperature stage heat exchanger 210 is used to condense the high-temperature refrigerant output from the first compression stage; the low-temperature stage heat exchanger 220 is used for the evaporation and heat absorption of the refrigerant in the second compression stage; and the intermediate heat exchanger 230 is used for the heat coupling exchange between the high and low temperature stage refrigerants, and its preferred structure is a spiral plate type or a spray film type.

[0038] Technical benefits: The three-stage heat exchange structure enables high-temperature condensation, low-temperature heat absorption, and intermediate-stage thermal coupling, optimizing the refrigerant path and energy utilization efficiency.

[0039] The multi-stage cooling system 300 includes two-stage compression units. The first compression stage is connected to the high-temperature stage heat exchanger 210, and the second compression stage is connected to the low-temperature stage heat exchanger 220. The two stages are energy-linked and coupled through an intermediate heat exchanger 230. Each stage compressor is equipped with filters, check valves, and electronic expansion valves at its inlet and outlet for refrigerant cleanliness control, reverse flow protection, and precise throttling regulation.

[0040] Technical benefits: Through staged compression and coupled heat exchange, the system operates stably and has precise temperature control, making it suitable for continuous cooling needs in multiple zones from -30℃ to +10℃.

[0041] The control system 400 includes a PLC control unit, a touch-screen human-machine interface, an electromagnetic adjustment module, and sensor input terminals. The control system 400 is used to collect the refrigerant temperature difference between the two sides of the intermediate heat exchanger 230 in real time and dynamically adjust the compressor operating frequency and the opening degree of each expansion valve to achieve balanced regulation of the cooling capacity output of the cascade system. Simultaneously, it controls the refrigerant pump to output at variable frequency according to the liquid level in the receiver tank and the system load. When the liquid level is too low, the control system automatically switches to the bypass circuit to prevent the pump from running dry and being damaged.

[0042] Technical benefits: Enables fully automatic control and linkage response, significantly improving energy efficiency ratio, system operation safety and service life.

[0043] Inside the intermediate heat exchanger 230, a spray assembly is installed, including several adjustable-angle nozzles. Each nozzle adjusts its spray angle via a linked micro motor. The high-temperature refrigerant sprayed by the nozzles forms a liquid film layer covering the surface of the condenser tube.

[0044] The condenser tubes are divided into high-load and low-load zones, and the control system can dynamically control the nozzle flow rate in different zones to achieve precise energy regulation. The internal spiral turbulence vane structure is also designed to enhance flow field disturbance and improve heat transfer turbulence efficiency.

[0045] Technical benefits: This structure can significantly improve the uniformity of refrigerant evaporation / condensation, heat exchange rate and reaction response, and is especially suitable for industrial scenarios with rapid changes in cold load.

[0046] Example 2: Further Improved Structure and Control Algorithm

[0047] Further optimization based on Example 1:

[0048] The intermediate heat exchanger 230 is replaced with a shell insulation composite structure, and its shell is provided with a vacuum insulation layer to reduce environmental thermal interference during the heat exchange process.

[0049] The control system introduces a temperature difference fuzzy control algorithm, combined with a neural network to predict the target operating frequency of the compressor, thereby achieving self-learning adjustment capability;

[0050] The storage tank is equipped with a composite insulation layer on the outside and has a built-in liquid level float sensor and remote signal alarm module.

[0051] Technical effects: It enhances the accuracy and response speed of intermediate thermal coupling, while achieving optimal energy consumption allocation in the operation path of the compression system, and continuously optimizes system efficiency.

[0052] Working principle and usage process of this utility model:

[0053] This invention achieves efficient cooling and stable control of the target medium through a cascade refrigeration method that couples a two-stage refrigerant compression cycle with an intermediate heat exchanger. The overall system mainly consists of a liquid storage system 100, a multi-stage heat exchanger 200, a multi-stage cooling system 300, and a control system 400 working together. Its working principle is as follows:

[0054] First compression stage cycle high temperature stage: The high temperature stage compressor draws in low-pressure gaseous refrigerant from the high temperature stage evaporator, i.e., intermediate heat exchanger 230; after being compressed and pressurized, the refrigerant enters the high temperature stage heat exchanger 210 for condensation and heat release, and is converted into high-pressure liquid; the liquid refrigerant enters the intermediate heat exchanger 230 for evaporation after being throttled by the high temperature side expansion valve, and achieves heat exchange with the low temperature stage refrigerant.

[0055] The second compression stage cycle is the low-temperature stage: the low-temperature stage compressor draws in low-pressure refrigerant gas from the low-temperature stage heat exchanger 220 and compresses it; the high-temperature gaseous refrigerant flows into the condensation zone of the intermediate heat exchanger 230 for cooling and condensation; the condensed liquid refrigerant is expanded and throttled before entering the low-temperature stage heat exchanger 220 for evaporation and heat absorption, thus completing the cooling task.

[0056] Intermediate heat exchanger coupling mechanism: The high-temperature refrigerant evaporates and absorbs heat in the intermediate heat exchanger 230, while the low-temperature refrigerant condenses and releases heat in the same heat exchanger. To improve heat exchange efficiency, the heat exchanger is equipped with spiral baffles and a spray-type liquid film condensation structure, so that the refrigerant forms a thin film distributed on the condensation surface. The control system adjusts the compression frequency and expansion valve opening of each stage in real time according to the temperature difference on both sides of the intermediate heat exchanger to optimize the cooling output.

[0057] Liquid storage system and refrigerant circulation: The condensed liquid refrigerant is collected in the liquid storage tank. The refrigerant pump adjusts the refrigerant delivery according to the feedback signal from the liquid level sensor and the load change. The liquid storage system is equipped with a bypass pipe and a solenoid valve to switch to the backup circuit when the liquid level is too low, so as to avoid the pump running dry or the system being interrupted.

[0058] Intelligent control system functions: The control system 400 integrates a temperature scheduling module and a compressor energy efficiency control module; it monitors operating parameters such as temperature of each heat exchange node, compressor load, and current in real time; and it allows setting of target temperature zones and operating modes through a touch interface to achieve intelligent constant temperature operation without human intervention.

[0059] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cascade industrial chiller, characterized in that, include: The liquid storage system (100) includes a liquid storage tank with a refrigerant inlet and a refrigerant return port, and a refrigerant pump connected thereto for storing and transporting refrigerant; A multi-stage heat exchanger (200) includes: a high-temperature stage heat exchanger (210), a low-temperature stage heat exchanger (220), and an intermediate heat exchanger (230) disposed therebetween, wherein the intermediate heat exchanger (230) is used to realize heat exchange between the high and low temperature stage refrigerants. A multi-stage cooling system (300) includes a first compression stage and a second compression stage. The first compression stage is connected to the high-temperature stage heat exchanger (210), and the second compression stage is connected to the low-temperature stage heat exchanger (220). The first compression stage and the second compression stage are thermally coupled through the intermediate heat exchanger (230). It also includes a control system (400) for regulating compressor start-up and shutdown, refrigerant flow and heat exchange process.

2. The cascade industrial chiller according to claim 1, characterized in that: The intermediate heat exchanger (230) is a spiral plate or spray film structure, which has the function of refrigerant atomization or liquid film heat exchange; the liquid storage tank in the liquid storage system (100) is provided with an insulation layer and a liquid level detection component; each stage compressor in the multi-stage cooling system (300) is provided with a filter, a check valve and an electronic expansion valve to achieve graded control.

3. A cascade industrial chiller according to claim 1, characterized in that, The intermediate heat exchanger (230) is equipped with a spray assembly, which includes several adjustable-angle nozzles for atomizing the high-temperature refrigerant into a liquid film and distributing it on the surface of the condenser tube. The intermediate heat exchanger (230) is equipped with a spiral turbulence structure to increase the degree of heat exchange turbulence.

4. A cascade industrial chiller according to claim 1, characterized in that, The refrigerant pump connected to the liquid storage tank is frequency-controlled by the control system based on the liquid level signal of the liquid storage tank and the compressor load status, so as to achieve on-demand refrigerant supply.

5. A cascade industrial chiller according to claim 1, characterized in that, The control system (400) is equipped with a temperature scheduling module, which is used to dynamically adjust the operating frequency and expansion valve opening of the high-temperature stage and low-temperature stage compressors according to the temperature difference on both sides of the intermediate heat exchanger, so as to achieve balanced adjustment of the cooling output of the cascade stage.

6. A cascade industrial chiller according to claim 3, characterized in that, The nozzles in the spray assembly are mounted on a rotating shaft, and the rotating shaft is linked to a micro motor located outside the intermediate heat exchanger (230) to achieve automatic adjustment of the spray angle of the nozzles according to the internal temperature gradient of the heat exchanger.

7. A cascade industrial chiller according to claim 4, characterized in that, The liquid storage system (100) is equipped with a refrigerant bypass pipeline and an electromagnetic switching valve. When the liquid level in the storage tank is lower than a preset threshold, the control system (400) automatically switches to the bypass path to avoid pump damage from running dry.

8. A cascade industrial chiller according to claim 3, characterized in that, The intermediate heat exchanger (230) is equipped with multiple sets of parallel condenser tubes. The condenser tube area is divided into a high load area and a low load area. The control system automatically adjusts the flow rate and spray time of the atomizing nozzle in each area according to the current heat exchange efficiency.

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