Double-unit cascade refrigeration air conditioning unit

Abstract

The utility model provides a double-unit cascade refrigeration air-conditioning unit, which comprises two sets of independent refrigeration air-conditioning units and a set of control system, the two sets of refrigeration air-conditioning units are arranged in parallel back to back, and the control system is connected with an electrical junction box of the refrigeration air-conditioning units through a cable. According to the scheme, the operation mode can be flexibly adjusted according to the heat and humidity load, double machines operate simultaneously when the heat and humidity load is large in summer, and rapid cooling and dehumidification can be achieved; in transition seasons or when heat and humidity loads are small, single machine operation is achieved, and energy can be saved; and the two units are backup for each other, when one device breaks down, the other device can be immediately put into work, it is guaranteed that the engineering environment is within the required range, meanwhile, the use input rate of a single device can be reduced, the service life is effectively prolonged, and the operation reliability of the whole air conditioning system is improved.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration and air conditioning technology, and in particular to a dual-unit cascade refrigeration and air conditioning unit. Background Technology

[0002] Existing underground engineering air conditioning systems mostly adopt single-unit design based on maximum load, which has the following technical problems: energy waste: during transitional seasons or low load periods, single units frequently start and stop or operate at full load, resulting in low energy efficiency ratios; insufficient reliability: when a single unit fails, it cannot maintain the ambient temperature and humidity, which may lead to equipment damage, especially in critical projects; high maintenance costs: long-term high-load operation of single units shortens the lifespan of core components such as compressors and fans, leading to frequent maintenance and replacement; low control precision: traditional control methods cannot dynamically adjust according to real-time load, making it difficult to balance cooling speed and energy-saving requirements.

[0003] Existing dual-machine parallel solutions are mostly simple physical parallel connections, lacking load-based intelligent switching logic and automatic fault backup mechanisms. They have not formed a systematic cascade control scheme and are difficult to meet actual engineering needs. Utility Model Content

[0004] The purpose of this utility model is to provide a dual-unit cascade refrigeration air conditioning unit, which aims to solve the problems of energy waste during the transition season caused by the design of existing underground engineering air conditioning systems based on maximum load, environmental control interruption when a single unit fails, frequent equipment start-up and shutdown, and shortened lifespan due to long-term high-load operation.

[0005] According to one objective of this utility model, this utility model provides a dual-unit cascade refrigeration air conditioning unit, including two independent refrigeration air conditioning units and a control system; the two refrigeration air conditioning units are arranged back-to-back in parallel, and the control system is connected to the electrical junction box of the refrigeration air conditioning units via cables.

[0006] Furthermore, each of the aforementioned refrigeration and air conditioning units includes a compressor, a condenser, an evaporator, an expansion valve, and a dryer filter. The compressor, the condenser, the expansion valve, the dryer filter, and the evaporator are connected by copper pipes to form a closed refrigeration system. A temperature sensor is installed at the inlet of the evaporator, and a centrifugal fan is installed at the outlet of the evaporator. A forced air supply channel is formed between the centrifugal fan and the evaporator.

[0007] Furthermore, the two sets of the refrigeration and air conditioning units are connected by a frame, and a guide plate is provided on the frame. The guide plate is located between the evaporator and the centrifugal fan to optimize the airflow field.

[0008] Furthermore, the compressor's exhaust pipe is equipped with a high-pressure protection switch, and the evaporator's return pipe is equipped with a low-pressure protection switch. The high-pressure protection switch and the low-pressure protection switch are electrically connected to the electrical junction box.

[0009] Furthermore, the control system includes a temperature comparison module, an operation mode switching module, a fault detection module, and a timing unit. The temperature comparison module is used to compare the measured temperature with the set temperature, and the operation mode switching module automatically selects single-machine or dual-machine operation according to the load.

[0010] Furthermore, the control system incorporates a temperature difference threshold adjustment unit, which is used to set the temperature difference threshold of the temperature comparison module.

[0011] Furthermore, the timing unit is used to record the cumulative operating time of the two sets of refrigeration and air conditioning units, and the operating mode switching module prioritizes the unit with the shorter cumulative operating time.

[0012] Furthermore, the fault detection module includes a current detection unit and a pressure detection unit. The current detection unit is used to monitor the compressor's operating current, and the pressure detection unit is used to monitor the high and low pressures of the refrigeration system.

[0013] Furthermore, a shock-absorbing support is provided at the bottom of the frame, which includes a spring shock absorber and a rubber pad to reduce the vibration during unit operation.

[0014] Furthermore, a condensate collection tray is provided below the evaporator, the collection tray is connected to a drain pipe, and the drain pipe is equipped with a U-shaped water seal structure.

[0015] This utility model technical solution includes two independent refrigeration and air conditioning units and a control system. The two refrigeration and air conditioning units are arranged back-to-back in parallel, and the control system is connected to the electrical junction box of the refrigeration and air conditioning units via cables. This solution can flexibly adjust the operating mode according to the heat and humidity load. When the heat and humidity load is high in summer, both units can operate simultaneously for rapid cooling and dehumidification; during transitional seasons or when the heat and humidity load is low, a single unit can operate to save energy. Moreover, the two units serve as backups for each other. When one unit fails, the other can immediately take over, ensuring that the engineering environment remains within the required range. At the same time, it can reduce the utilization rate of a single unit, effectively extend its service life, and improve the operational reliability of the entire air conditioning system. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a system structure diagram of a dual-unit cascade refrigeration air conditioning unit according to an embodiment of the present invention;

[0018] Figure 2 This is a unit layout diagram of a dual-unit cascade refrigeration air conditioning unit according to an embodiment of this utility model;

[0019] Figure 3 This is a logic flowchart of the control system of the dual-unit cascade refrigeration air conditioning unit according to an embodiment of the present invention;

[0020] In the diagram: 1. Temperature sensor; 2. Evaporator; 3. Electronic expansion valve; 4. Centrifugal fan; 5. Dryer filter; 6. Electrical junction box; 7. Compressor; 8. Condenser; 9. Frame; 10. Vibration damping support. Detailed Implementation

[0021] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Example 1

[0025] like Figures 1-3 As shown, a dual-unit cascade refrigeration air conditioning unit includes a dual-unit independent parallel structure and an intelligent control system, wherein:

[0026] The dual-unit independent parallel structure includes two sets of refrigeration and air conditioning units, which are arranged back to back. Each set of refrigeration and air conditioning units includes an independent compressor, condenser and evaporator, which are connected by copper pipes to form a closed refrigeration system that can operate independently or in coordination.

[0027] Specifically, the two refrigeration and air conditioning units are fixed back-to-back by a frame 9. The compressor 7 of each unit discharges high-pressure refrigerant gas, which is condensed by the condenser 8 and then passes through the dryer filter 5 and the electronic expansion valve 3 for throttling before entering the evaporator 2 for evaporation and heat absorption. The low-temperature vapor is then drawn into the compressor to complete the cycle. The evaporator inlet temperature sensor 1 monitors the return air temperature in real time, and the centrifugal fan 4 forces airflow at the evaporator outlet, while the deflector plate optimizes the airflow direction.

[0028] The intelligent control system integrates temperature comparison, mode switching, fault detection, and timing modules. It automatically adjusts the operating mode based on the difference between the measured temperature and the set temperature (T1-T2). The operating logic of the intelligent control system is as follows:

[0029] Startup initialization: After receiving the start signal, centrifugal fan 4 starts for 30 seconds to ensure unobstructed airflow;

[0030] Temperature sampling: Temperature sensor 1 collects the return air temperature T1 at 10-second intervals and transmits it to the control system;

[0031] Pattern detection:

[0032] If T1 < T2, only the fan will run, and the compressor will not start.

[0033] If T1 > T2 + T3 (e.g., T3 = 3℃), the control system will simultaneously activate the compressors of both units for rapid cooling.

[0034] If T2 < T1 ≤ T2 + T3, the unit operates independently and prioritizes the unit with the shorter cumulative running time. The timing unit data is called, and the unit with the smaller cumulative running time t1 and t2 is started. If the cumulative running time t1 of air conditioning unit #1 is < the cumulative running time t2 of air conditioning unit #2, then air conditioning unit #1 is started. If the cumulative running time t1 of air conditioning unit #1 is > the cumulative running time t2 of air conditioning unit #2, then air conditioning unit #2 is started.

[0035] Where: T1 is the measured return air temperature; T2 is the set temperature; T3 is the temperature difference threshold; t1 is the cumulative operating time of Unit 1; t2 is the cumulative operating time of Unit 2.

[0036] Fault handling: When a unit fails, it automatically switches to another unit and alarms; if the current detection unit detects that the compressor current exceeds 120% of the rated value, or the pressure detection unit detects that the high pressure is ≥2.5MPa / low pressure is ≤0.1MPa, the fault detection module cuts off the power supply to the faulty unit, automatically starts another unit, and sends an alarm signal through the RS485 interface.

[0037] This utility model of a dual-unit cascade refrigeration air conditioning unit is highly efficient and energy-saving. Under low load, the energy consumption of a single unit is reduced by 50%, and in economic operation mode, energy consumption is further reduced by 15%-20%. This utility model of a dual-unit cascade refrigeration air conditioning unit features high reliability, with the two units serving as hot backups for each other. Fault switching time is <10 seconds, and the system's continuous operation rate is ≥99.9%. It has a long lifespan; the alternating operation of the two units ensures that the load rate of a single unit is ≤50%, extending the lifespan of core components by 30%-50%. It enables precise control; the electronic expansion valve and forced air supply design achieve a cooling rate up to twice that of a single unit, with a temperature control accuracy of ±0.5℃.

[0038] Example 2

[0039] like Figures 1-3 As shown, the structure of this embodiment is basically the same as that of embodiment 1. The difference is that the dual-unit cascade refrigeration air conditioning unit in this embodiment includes two independent refrigeration air conditioning units and a control system. The two sets of refrigeration air conditioning units are arranged back to back in parallel, and the control system is connected to the electrical junction box of the refrigeration air conditioning units through cables.

[0040] Each refrigeration and air conditioning unit includes a compressor 7, a condenser 8, an evaporator 2, an electronic expansion valve 3, a dryer filter 5, a temperature sensor 1, a centrifugal fan 4, an electrical junction box 6, and a frame 9. The compressor 7, condenser 8, electronic expansion valve 3, dryer filter 5, and evaporator 2 are connected by copper pipes to form a closed refrigeration system.

[0041] A temperature sensor 1 is installed at the inlet of the evaporator 2, and a centrifugal fan 4 is installed at the outlet of the evaporator 2, forming a forced air supply channel between the centrifugal fan 4 and the evaporator 2.

[0042] Two refrigeration and air conditioning units are fixed back-to-back by a frame 9. Vibration damping supports 10 are installed at the bottom of the frame 9, including spring dampers and rubber pads, to reduce unit operating vibration and improve system stability. Specifically, four sets of spring dampers are installed at the bottom of the frame 9, with a rubber pad on top of each set, and a vibration transmission ratio ≤0.3.

[0043] A baffle plate is installed on the frame 9 of the refrigeration and air conditioning unit, located between the evaporator 2 and the centrifugal fan 4, to optimize the airflow. A removable access panel is also installed on the frame 9 of the refrigeration and air conditioning unit, corresponding to the locations of the compressor, condenser, and evaporator.

[0044] The compressor 7's exhaust pipe is equipped with a high-pressure protection switch, and the evaporator 2's return pipe is equipped with a low-pressure protection switch. The high-pressure protection switch and the low-pressure protection switch are electrically connected to the electrical junction box 6.

[0045] The electronic expansion valve 3 is electrically connected to the electrical junction box 6 and is used to automatically adjust its opening degree according to the superheat at the outlet of the evaporator 2. A condensate drip tray is installed below the evaporator 2, and the drip tray is connected to a drain pipe with a U-shaped water seal structure. The slope of the condensate drip tray below the evaporator is ≥3%, and the height of the U-shaped water seal is ≥50mm to prevent odor backflow.

[0046] The control system includes a temperature comparison module, an operation mode switching module, a fault detection module, and a timing unit. The temperature comparison module is used to compare the measured temperature with the set temperature, and the operation mode switching module automatically selects single-machine or dual-machine operation according to the load.

[0047] The control system has a built-in temperature difference threshold adjustment unit, which is used to set the temperature difference threshold T3 of the temperature comparison module. The temperature difference threshold T3 can be adjusted on-site through the human-machine interface.

[0048] The timing unit is used to record the cumulative running time of the two refrigeration and air conditioning units. The operation mode switching module prioritizes the unit with the shorter cumulative running time.

[0049] The fault detection module includes a current detection unit and a pressure detection unit. The current detection unit is used to monitor the compressor's operating current, and the pressure detection unit is used to monitor the high and low pressures of the refrigeration system.

[0050] The control system is equipped with an RS485 communication interface, which is used to connect to the Building Automation System (BAS) for remote monitoring. The unit's operating status (temperature, pressure, current, running time, etc.) is uploaded to the BAS system via the RS485 interface, supporting real-time viewing and parameter adjustment via a mobile app.

[0051] The control system is set to an economic operation mode, which achieves energy-saving operation by reducing the centrifugal fan speed and compressor frequency. Economic operation mode: Automatically switches to economic mode from 22:00 to 6:00 at night, reducing the centrifugal fan speed to 70% of the rated value and the compressor frequency to 50Hz, reducing energy consumption by approximately 20%.

[0052] In operation, the high-pressure refrigerant gas discharged from compressor 7 is condensed by condenser 8, then dried and filtered by dryer filter 5, and finally throttled by electronic expansion valve 3 before entering evaporator 2. In evaporator 2, it absorbs heat from the outside air and evaporates into low-pressure refrigerant vapor, which is then drawn into compressor 7 for compression, thus completing one refrigeration cycle. After being cooled by evaporator 2, the air is forced out through ductwork by centrifugal fan 4, achieving a cooling effect.

[0053] After receiving the start signal, the centrifugal fan 4 starts first; temperature sensor 1 monitors the return air temperature T1 of the air conditioning unit in real time and feeds it back to the controller; the controller compares the return air temperature T1 with the temperature T2 required by the user for the air-conditioned room:

[0054] If T1 < T2, only the fan will run, and the compressor will not start.

[0055] If T1 > T2 + T3 (e.g., T3 = 3℃), the control system will simultaneously activate the compressors of both units for rapid cooling.

[0056] If T2 < T1 ≤ T2 + T3, the unit will operate independently and the unit with the shorter cumulative running time will be selected first. The timing unit data will be called to start the unit with the shorter cumulative running time.

[0057] Where: T1 is the measured return air temperature; T2 is the set temperature; T3 is the temperature difference threshold.

[0058] This invention utilizes a cascaded design to achieve mutual backup between the two units. During periods of high heat and humidity load in summer or when rapid cooling is required, both units can be operated simultaneously to meet the demands of rapid cooling and dehumidification. During transitional seasons or when the heat and humidity load within the project is low, operating only one unit is sufficient. Furthermore, if one unit malfunctions, the other can immediately take over, ensuring the project environment remains within acceptable limits.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A dual machine cascade refrigeration air conditioning unit, characterized in that, It includes two independent refrigeration and air conditioning units and a control system; the two refrigeration and air conditioning units are arranged back to back in parallel, and the control system is connected to the electrical junction box of the refrigeration and air conditioning units via cables.

2. The dual-unit cascade refrigeration air conditioning unit according to claim 1, characterized in that, Each of the aforementioned refrigeration and air conditioning units includes a compressor, a condenser, an evaporator, an expansion valve, and a dryer filter. The compressor, the condenser, the expansion valve, the dryer filter, and the evaporator are connected by copper pipes to form a closed refrigeration system. A temperature sensor is installed at the inlet of the evaporator, and a centrifugal fan is installed at the outlet of the evaporator. A forced air supply channel is formed between the centrifugal fan and the evaporator.

3. The dual-unit cascade refrigeration air conditioning unit according to claim 2, characterized in that, The two sets of the refrigeration and air conditioning units are connected by a frame, and a guide plate is provided on the frame. The guide plate is located between the evaporator and the centrifugal fan to optimize the air flow field.

4. The dual-unit cascade refrigeration air conditioning unit according to claim 2, characterized in that, The compressor's exhaust pipe is equipped with a high-pressure protection switch, and the evaporator's return pipe is equipped with a low-pressure protection switch. The high-pressure protection switch and the low-pressure protection switch are electrically connected to the electrical junction box.

5. The dual-unit cascade refrigeration air conditioning unit according to claim 1, characterized in that, The control system includes a temperature comparison module, an operation mode switching module, a fault detection module, and a timing unit. The temperature comparison module is used to compare the measured temperature with the set temperature. The operation mode switching module automatically selects single-machine or dual-machine operation according to the load.

6. The dual-unit cascade refrigeration air conditioning unit according to claim 5, characterized in that, The control system has a built-in temperature difference threshold adjustment unit, which is used to set the temperature difference threshold of the temperature comparison module.

7. The dual-unit cascade refrigeration air conditioning unit according to claim 6, characterized in that, The timing unit is used to record the cumulative operating time of the two sets of refrigeration and air conditioning units, and the operating mode switching module prioritizes the unit with the shorter cumulative operating time.

8. The dual-unit cascade refrigeration air conditioning unit according to claim 5, characterized in that, The fault detection module includes a current detection unit and a pressure detection unit. The current detection unit is used to monitor the compressor's operating current, and the pressure detection unit is used to monitor the high and low pressures of the refrigeration system.

9. The dual-unit cascade refrigeration air conditioning unit according to claim 3, characterized in that, The bottom of the frame is provided with a shock-absorbing support, which includes a spring shock absorber and a rubber pad to reduce the vibration of the unit during operation.

10. The dual-unit cascade refrigeration air conditioning unit according to claim 2, characterized in that, A condensate collection tray is provided below the evaporator, and the collection tray is connected to a drain pipe, which is equipped with a U-shaped water seal structure.

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