A control system and method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit

Abstract

The present invention relates to the field of air conditioning and refrigeration technology, and in particular to a control system and method for a dual-refrigeration circuit series reverse flow large temperature difference hot and cold air unit; in the present invention, the filter of the hot and cold air unit is located at the return air outlet; the first evaporator, the first compressor, the first condenser, and the expansion valve are connected in series in sequence to form a first refrigeration circuit; the connection end of the first compressor and the first evaporator is located at the air outlet of the first evaporator; the connection end of the first compressor and the first condenser is located at the air inlet of the first condenser; the first evaporator and the second evaporator are placed vertically front and back according to the air flow direction, and the second evaporator is close to the return air outlet; the evaporator and the condenser are arranged in a cross-arrangement manner, so that the wind on one side can be cooled to a lower temperature in the air conditioner, and the wind on the other side can be heated to a higher temperature in the air conditioner, thereby reducing the air duct area and the air conditioner volume, and solving the problem of installing and using the air conditioner in a narrow space.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning and refrigeration, and in particular to a control system and method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit. Background Art

[0002] At present, my country is vigorously developing mineral resources and building new underground transportation facilities, in places where underground tunnel operations are required, such as coal mining and construction of roads and railways.

[0003] When working in underground tunnels, it is usually impossible to install air-conditioning units because the working space is too small, resulting in difficulties in ventilation and heat dissipation, a poor working environment, and low work efficiency. The hot and cold air units that can be installed in small places such as underground tunnels also have a small cooling capacity and poor cooling effect due to the existing parallel installation method of the evaporator and condenser, and the unit itself and the supply and exhaust air ducts occupy a large space. In addition, in the current hot and cold air units, the refrigeration system usually adopts a single circuit or a parallel double circuit. This type of design has significant limitations in the face of complex requirements (such as when a large temperature difference effect needs to be achieved); specifically, in the parallel double-circuit system, the distribution and flow control of the refrigerant are relatively extensive, relying on the expansion valve setting and static pipeline design, which can easily lead to uneven refrigerant distribution when the load changes, resulting in inconsistent working efficiency of each circuit.

[0004] In the existing solutions, in order to achieve uniform cooling effect among multiple circuits, fixed expansion valves or electronic expansion valves are generally used to adjust the refrigerant flow rate, but it is still impossible to monitor and dynamically adjust the actual needs of each refrigeration circuit in real time, which is prone to problems such as circuit imbalance, temperature difference cannot be met, and reduced energy efficiency; some circuits may be over-cooled or have insufficient cooling capacity, resulting in a decrease in overall efficiency, and in applications requiring a large temperature difference, the fixed refrigerant distribution method cannot fully utilize the system capacity and cannot achieve the expected temperature difference effect; similarly, due to the uneven distribution of circuit loads, the compressor and other components cannot operate in the optimal state, resulting in increased energy consumption. Therefore, there is an urgent need for a control system and method for a dual refrigeration circuit series reverse flow large temperature difference hot and cold air unit to solve such problems. Summary of the invention

[0005] To this end, the present invention provides a control system and method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, which is used to overcome the problems of parallel installation of evaporators and condensers in the prior art, small cooling capacity, poor cooling effect, large space occupied by the unit itself and the supply and exhaust air ducts; circuit imbalance, unsatisfactory temperature difference and reduced energy efficiency.

[0006] To achieve the above-mentioned object, on the one hand, the present invention provides a control system for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, comprising: a cold and hot air unit, comprising a first compressor, a second compressor, a first evaporator, a second evaporator, a first condenser, a second condenser, a fan, an electronic expansion valve and a filter; the cold and hot air unit adopts a cross arrangement of the evaporator and the condenser, so that the wind on one side lowers the temperature in the air conditioner, and the wind on the other side raises the temperature in the air conditioner;

[0007] The cold and hot air units adopt a counter-flow double-circuit design, which makes the refrigerant flow in opposite directions in the two refrigeration circuits, and uses the temperature difference to improve efficiency;

[0008] The data acquisition module includes a temperature sensor, a pressure sensor, a flow sensor, and a data acquisition device; the data acquisition module uses sensors to monitor the real-time data of each refrigeration circuit in real time, including temperature, pressure, and flow, and transmits the data to the control system;

[0009] The data acquisition module provides real-time data as the basis for dynamic adjustment;

[0010] Dynamic refrigerant distribution and regulation module, with built-in refrigerant distributor, which cooperates with the electronic expansion valve and uses control algorithm to dynamically adjust the refrigerant flow of each refrigeration circuit based on real-time data;

[0011] The dynamic refrigerant distribution and regulation module adjusts the refrigerant flow according to real-time data to achieve precise control;

[0012] Intelligent circuit management module controls the start-up sequence and operating frequency of each refrigeration circuit according to the current load and temperature difference requirements of the system;

[0013] The modules can shut down some circuits to save energy under low load conditions and work together to improve efficiency under high load conditions;

[0014] The intelligent loop management module includes: loop start controller, load analysis unit and loop frequency controller;

[0015] The intelligent loop management module intelligently manages the start and stop and frequency of the loop according to load demand;

[0016] The load adaptation and large temperature difference adjustment module optimizes the refrigerant distribution and circuit working status based on real-time monitoring data for special application scenarios that require large temperature differences;

[0017] The load adaptation and large temperature difference regulation module optimizes the overall operation status of the system for scenarios with large temperature difference requirements.

[0018] Furthermore, in the cold and hot air unit, the filter is located at the return air port; the first evaporator, the first compressor, the first condenser, and the expansion valve are connected in series in sequence to form a first refrigeration circuit; the second evaporator, the second compressor, the second condenser, and the expansion valve are connected in series in sequence to form a second refrigeration circuit; the connection end of the first compressor and the first evaporator is located at the air outlet of the first evaporator; the connection end of the first compressor and the first condenser is located at the air inlet of the condenser; the connection end of the electronic expansion valve and the first evaporator is located at the liquid inlet of the first evaporator; the connection end of the electronic expansion valve and the first condenser is located at the liquid outlet of the first condenser; the second refrigeration circuit is similar; the first refrigeration circuit and the second refrigeration circuit are cross-arranged;

[0019] The first evaporator and the second evaporator are placed vertically front and back according to the air flow direction, and the second evaporator is close to the return air outlet;

[0020] The first condenser and the second condenser are placed vertically front and back according to the air flow direction, and the first condenser is close to the return air outlet;

[0021] The cold and hot air unit also includes an air outlet, and the fan is placed at the air outlet; the air outlet on the evaporator side is the cold air outlet, and the air outlet on the condenser side is the hot air outlet.

[0022] On the other hand, the present invention also provides a control method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, comprising:

[0023] Step S1, dual-circuit series counter-flow deployment, using dual refrigeration circuits in series counter-flow mode to deploy the hot and cold air units, the refrigerants of the two refrigeration circuits flow in opposite directions, thereby maximizing the use of temperature differences, improving the cooling effect and overall system efficiency; the counter-flow mode not only enhances the cooling capacity of the system, but also facilitates dynamic adjustment;

[0024] Step S2, dynamic refrigerant distribution, installing real-time monitoring equipment in each refrigeration circuit to collect temperature, pressure, and flow parameters;

[0025] Step S3, intelligent circuit startup and load adjustment, adjusts the startup sequence and operating frequency of the refrigeration circuit according to the current load situation and temperature difference requirements; under low load conditions, only one circuit is selected to operate; under high load conditions, the two circuits work together, making full use of the advantages of the reverse flow design. By coordinating with the dynamic refrigerant distribution in step S2, the system can avoid the problem of load imbalance between circuits, thereby improving the overall energy efficiency;

[0026] Step S4, load adaptation and large temperature difference adjustment, optimizing the distribution of refrigerant and the coordinated control of the circuit, and providing the maximum temperature difference effect under special needs;

[0027] In applications such as tunnel cooling or special industrial cooling, the working state of the circuit is automatically optimized through analysis and adjustment of real-time monitoring data, so that the temperature difference always reaches the optimal value and avoids unnecessary energy consumption increase.

[0028] Furthermore, in step S2, the control system dynamically adjusts the refrigerant flow rate using an adjustable electronic expansion valve and a refrigerant distributor based on real-time data in combination with the current load and temperature difference requirements; the dynamic distribution mechanism is combined with a dual-circuit series design to ensure precise control of the refrigerant flow rate, so that the refrigeration effect of each refrigeration circuit is optimized.

[0029] Furthermore, in step S2, the dynamic refrigerant distribution method is:

[0030] Monitoring parameters include: real-time temperature , real-time pressure , real-time refrigerant flow ,load , target temperature difference and The efficiency of the circuit ;

[0031] Construct an objective function to adjust the refrigerant flow rate of each refrigeration circuit Make the control system meet the load demand and temperature difference requirements While optimizing system efficiency , the objective function is: ,in: represents the weight coefficient, Indicates the maximum pressure allowed by the system. Indicates A circuit, Indicates the total number of circuits;

[0032] Based on the objective function, the gradient descent method is used to adjust the opening of the electronic expansion valve and the setting value of the refrigerant distributor control , refrigerant flow adjustment method: ,in represents the flow coefficient determined based on fluid characteristics, Indicates the opening area of ​​the expansion valve, Indicates the circuit pressure drop, Indicates Temperature difference of the circuit;

[0033] The Lagrange multiplier method is used to solve the objective function and obtain the optimal Corresponding and , the specific steps include:

[0034] Calculate the gradient of the objective function ;

[0035] Adjustment by gradient descent and Reduce the objective function value.

[0036] In each iteration, according to the current Recalculate temperature difference and load , and update and until it converges to the optimal value.

[0037] Furthermore, in step S2, the dynamic refrigerant distribution method further includes:

[0038] Based on real-time monitoring of load and temperature difference The control target is updated through the feedback mechanism:

[0039] ,in represents the specific heat capacity of the refrigerant, No. The mass flow rate of the loop, denote the circuit inlet and outlet temperatures respectively;

[0040] Dynamically adjust the weight coefficients using an adaptive adjustment mechanism based on multivariable control , so that the system maintains the optimal performance state under different working conditions. This process uses the Bayesian optimization algorithm to gradually approach the global optimal solution through iterative experiments. The Bayesian optimization formula is:

[0041] ,in represents the expected value of the objective function;

[0042] This enables precise control of refrigerant flow under complex load and temperature difference requirements.

[0043] Furthermore, the smart loop startup and load adjustment method in step S3 is:

[0044] Define real-time monitoring parameters, including: current system total load demand , target temperature difference , No. Real-time refrigerant flow rate of the circuit , specific heat capacity of refrigerant , No. Circuit inlet temperature , No. Circuit outlet temperature , and Mass flow rate of the loop ;

[0045] To perform a total load calculation: ,in, is the number of loops, is the refrigerant flow rate of each circuit;

[0046] Assign loop priorities and define priority functions , determines the startup order of the circuit:

[0047] ,in and Represents the weight coefficient, adjusting the impact of temperature difference and load on priority, Indicates The temperature difference of the circuit, Indicates The load contribution of the circuit;

[0048] according to The values ​​are sorted from large to small, and the circuit with the highest priority is started first.

[0049] Furthermore, in step S3, the smart loop startup and load adjustment method further includes:

[0050] Defining the start threshold : ,in and Indicates the adjustment coefficient, balancing the influence of load and temperature difference, Indicates the maximum load capacity of the system. Indicates the maximum temperature difference that the system can achieve;

[0051] When the priority of a circuit Exceeding the threshold , start the circuit.

[0052] For the activated circuit , adjust its operating frequency Matching system requirements:

[0053] ,in represents the fundamental frequency of the loop, Indicates the frequency adjustment coefficient, which controls the frequency change amplitude;

[0054] Perform load balancing and dynamic adjustment, and define load balancing indicators :

[0055] ,in Indicates the total refrigerant flow rate of the system;

[0056] when Exceeding a certain threshold When the load is balanced, the frequency or flow of the circuit is dynamically adjusted;

[0057] Dynamic adjustment method: real-time monitoring , change the opening of the expansion valve according to the system response and the setting value of the refrigerant distributor To achieve the refrigerant flow and operating frequency Fine-tuning.

[0058] Furthermore, in step S3, the smart loop startup and load adjustment method further includes:

[0059] Using a closed-loop feedback mechanism, real-time monitoring and changes, including and Dynamic adjustment of internal parameters:

[0060] Define the overall optimization objective function :

[0061] ,in Indicates The efficiency of the circuit, Indicates the temperature difference adjustment weight, balancing energy consumption and temperature difference effect;

[0062] Gradient descent method and genetic algorithm are used to gradually adjust the frequency and flow of the loop to achieve the optimal performance of the system as a whole;

[0063] Perform system stability and preventive adjustments, and regularly calculate system stability indicators :

[0064] ,when Early warning when exceeding the set range;

[0065] Based on historical data and prediction models, possible load peaks are estimated, and additional circuits are started in advance or the frequency of existing circuits is adjusted to ensure stable system operation.

[0066] Further, in step S4, the load adaptation and large temperature difference adjustment method includes:

[0067] Continuous monitoring of system parameters, including real-time data of each refrigeration circuit, as well as external environmental conditions (temperature and humidity in the tunnel);

[0068] Use historical data and current monitoring data for analysis to identify current system load conditions and temperature difference requirements;

[0069] The analysis includes identifying load peaks and temperature demand trends;

[0070] Identify special requirements in the current application scenario, including the need for a larger temperature difference during a certain period of time to cope with the sharp rise in temperature in the tunnel;

[0071] Automatically set new temperature difference targets and load distribution strategies based on identified demand;

[0072] Select the circuit that can provide the largest temperature difference effect, and shut down or reduce the operating frequency of other circuits as needed;

[0073] By optimizing the coordination between circuits, the distribution of refrigerant in each circuit is more balanced and efficient;

[0074] In step S4, dynamic adjustment and real-time response are performed:

[0075] Based on real-time monitoring data, the system dynamically adjusts the refrigerant distribution and circuit working status; temporarily increases the refrigerant flow or working frequency of certain circuits when the load suddenly increases;

[0076] The system automatically adjusts the working mode of the loop by balancing the relationship between the temperature difference target and energy consumption; when the temperature difference demand decreases, the system will reduce the working frequency of some loops or close some loops;

[0077] The system continuously monitors the load distribution of each circuit to ensure that the refrigerant distribution is balanced among the circuits.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] The present invention arranges the evaporator and the condenser in a cross-arrangement manner so that the wind on one side can be cooled to a lower temperature in the air-conditioning unit, while the wind on the other side can be heated to a higher temperature in the air-conditioning unit, thereby improving the cooling and heating capacity per unit air volume, reducing the air duct area and the volume of the air conditioner, and solving the problem of installing and using the air conditioner in a narrow space.

[0080] The present invention monitors the temperature, pressure and flow parameters of each circuit in real time, utilizes an adjustable electronic expansion valve and a refrigerant distributor, and dynamically adjusts the refrigerant flow according to actual needs, so that the refrigerant flow of each refrigeration circuit is maintained at an optimal level, thereby improving the efficiency and temperature difference effect of the overall system.

[0081] The present invention intelligently determines the start-up sequence and operating frequency of each circuit according to the current load conditions and temperature difference requirements; when the load is low, only one circuit is operated to save energy; when the load is high, the two circuits work together; and by accurately controlling the refrigerant distribution, the load imbalance problem in the existing system is avoided.

[0082] The present invention can achieve the maximum temperature difference under special requirements by optimizing the distribution of refrigerant, which plays a key role in certain specific application scenarios (such as tunnel cooling, special industrial cooling, etc.); according to real-time monitoring data, the circuit working state is automatically adjusted to ensure that the temperature difference always reaches the optimal value.

[0083] The present invention adopts a dual-circuit coordinated control method based on refrigerant distribution optimization, introduces dynamic refrigerant distribution and circuit collaborative control mechanism, and realizes a more efficient and intelligent refrigeration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 It is a schematic diagram of the control system structure of the dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit of the present invention;

[0085] Figure 2 It is a flow chart of the control method of the dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit of the present invention;

[0086] Figure 3 It is a schematic diagram of the structure of the dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit of the present invention.

[0087] Legend:

[0088] 1. First compressor; 2. Second compressor; 3. First evaporator; 4. Second evaporator; 5. First condenser; 6. Second condenser; 7. Air blower; 8. Electronic expansion valve; 9. Filter. DETAILED DESCRIPTION

[0089] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0090] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0091] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1

[0092] See also Figure 1-Figure 3 The present invention provides a control system for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, comprising:

[0093] The hot and cold air unit comprises a first compressor, a second compressor, a first evaporator, a second evaporator, a first condenser, a second condenser, a fan, an electronic expansion valve and a filter; the hot and cold air unit adopts a cross arrangement of the evaporator and the condenser, so that the wind on one side lowers the temperature in the air conditioner, and the wind on the other side raises the temperature in the air conditioner;

[0094] The cold and hot air units adopt a counter-flow double-circuit design, which makes the refrigerant flow in opposite directions in the two refrigeration circuits, and uses the temperature difference to improve efficiency;

[0095] The data acquisition module includes a temperature sensor, a pressure sensor, a flow sensor, and a data acquisition device; the data acquisition module uses sensors to monitor the real-time data of each refrigeration circuit in real time, including temperature, pressure, and flow, and transmits the data to the control system;

[0096] The data acquisition module provides real-time data as the basis for dynamic adjustment;

[0097] Dynamic refrigerant distribution and regulation module, with built-in refrigerant distributor, which cooperates with the electronic expansion valve and uses control algorithm to dynamically adjust the refrigerant flow of each refrigeration circuit based on real-time data;

[0098] The dynamic refrigerant distribution and regulation module adjusts the refrigerant flow according to real-time data to achieve precise control;

[0099] Intelligent circuit management module controls the start-up sequence and operating frequency of each refrigeration circuit according to the current load and temperature difference requirements of the system;

[0100] The modules can shut down some circuits under low load conditions to save energy and work together under high load conditions to improve efficiency;

[0101] The intelligent loop management module includes: loop start controller, load analysis unit and loop frequency controller;

[0102] The intelligent loop management module intelligently manages the start and stop and frequency of the loop according to load demand;

[0103] The load adaptation and large temperature difference adjustment module optimizes the refrigerant distribution and circuit working status based on real-time monitoring data for special application scenarios that require large temperature differences;

[0104] The load adaptation and large temperature difference regulation module optimizes the overall operation status of the system for scenarios with large temperature difference requirements.

[0105] In the cold and hot air unit, the filter is located at the return air port; the first evaporator, the first compressor, the first condenser, and the expansion valve are connected in series in sequence to form a first refrigeration circuit; the second evaporator, the second compressor, the second condenser, and the expansion valve are connected in series in sequence to form a second refrigeration circuit; the connection end of the first compressor and the first evaporator is located at the air outlet of the first evaporator; the connection end of the first compressor and the first condenser is located at the air inlet of the condenser; the connection end of the electronic expansion valve and the first evaporator is located at the liquid inlet of the first evaporator; the connection end of the electronic expansion valve and the first condenser is located at the liquid outlet of the first condenser; the second refrigeration circuit is similar; the first refrigeration circuit and the second refrigeration circuit are cross-arranged;

[0106] The first evaporator and the second evaporator are placed vertically front and back according to the air flow direction, and the second evaporator is close to the return air outlet;

[0107] The first condenser and the second condenser are placed vertically front and back according to the air flow direction, and the first condenser is close to the return air outlet;

[0108] The cold and hot air unit also includes an air outlet, and the fan is placed at the air outlet; the air outlet on the evaporator side is the cold air outlet, and the air outlet on the condenser side is the hot air outlet.

[0109] Specifically, when the hot and cold air units are started, the two fans are started first, and then the first refrigeration circuit is started. After it runs stably, the other group is started to avoid excessive circuit current during parallel startup. At this time, the evaporator is in contact with the high-temperature heat source, and the liquid working medium is heated by the high-temperature heat source in the evaporator and evaporates into gas, and absorbs heat. The evaporated gas is extracted and compressed by the compressor to become a high-temperature and high-pressure state and is transported to the condenser. The high-temperature and high-pressure gaseous refrigerant dissipates heat in the condenser and becomes a liquid refrigerant, and then returns to the evaporator through the electronic expansion valve 8 for the next cycle.

[0110] When the air outside the air-conditioning unit enters the unit through the filter 9, the air will be divided into two paths and enter the evaporation side and condensation side of the air-conditioning unit respectively; the air entering the evaporation side will first pass through the second evaporator 4 to cool down, and then pass through the first evaporator 3 to continue to cool down to a lower temperature before being sent to the cooling area by the evaporation side air supply fan; the air entering the condensation side will first pass through the first condenser 5 to heat up, and then pass through the second condenser 6 to continue to heat up to a higher temperature before being sent to the heat dissipation area by the condensation side air supply fan.

[0111] At this time, the evaporation temperature of the second evaporator 4 is higher than that of the first evaporator 3, and the condensation temperature of the second condenser 6 is higher than that of the first condenser 5, that is, the evaporation temperature and the condensation temperature in the second refrigeration circuit are relatively high, and the condensation temperature and the evaporation temperature in the first refrigeration circuit are relatively low, thereby effectively balancing the temperature difference between the evaporation temperature and the condensation temperature in different refrigeration circuits, and making the evaporation and condensation pressure differences of the two refrigeration circuits close, so that the power consumption of the two compressors is close.

[0112] Finally, the processed hot and cold air are discharged by the fans on the evaporation side and the condensation side respectively. The two-stage evaporator and condenser are placed vertically, which can reduce the supply air temperature on the evaporator side to a lower temperature and raise the return air temperature on the condenser side to a higher temperature, so that the same size unit can take away more heat.

[0113] The present invention also provides a control method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, comprising:

[0114] Step S1, dual-circuit series counter-flow deployment, using dual refrigeration circuits in series counter-flow mode to deploy the hot and cold air units, the refrigerants of the two refrigeration circuits flow in opposite directions, thereby maximizing the use of temperature differences, improving the cooling effect and overall system efficiency; the counter-flow mode not only enhances the cooling capacity of the system, but also facilitates dynamic adjustment;

[0115] Specifically, the dual-circuit series counter-flow design maximizes the use of temperature differences, significantly improving the cooling effect and overall efficiency. The counter-flow design not only enhances the cooling capacity of the system, but also facilitates dynamic adjustment, allowing the system to maintain efficient operation under different load conditions. When faced with large temperature difference requirements, it can fully tap the potential of each refrigeration circuit to achieve the best cooling effect.

[0116] Step S2, dynamic refrigerant distribution, installing real-time monitoring equipment in each refrigeration circuit to collect temperature, pressure, and flow parameters;

[0117] In step S2, the control system dynamically adjusts the refrigerant flow rate using an adjustable electronic expansion valve and a refrigerant distributor according to real-time data, combined with the current load and temperature difference requirements; the dynamic distribution mechanism is combined with the dual-circuit series design to ensure accurate control of the refrigerant flow rate, so that the refrigeration effect of each refrigeration circuit is optimized;

[0118] In step S2, the dynamic refrigerant distribution method is:

[0119] Monitoring parameters include: real-time temperature , real-time pressure , real-time refrigerant flow , load demand , target temperature difference and The efficiency of the circuit ;

[0120] Construct an objective function to adjust the refrigerant flow rate of each refrigeration circuit Make the control system meet the load demand and temperature difference requirements While optimizing system efficiency , objective function: ,in: represents the weight coefficient, Indicates the maximum pressure allowed by the system. Indicates A circuit, Indicates the total number of circuits;

[0121] Based on the objective function, the gradient descent method is used to adjust the opening of the electronic expansion valve and the setting value of the refrigerant distributor control , refrigerant flow adjustment method: ,in represents the flow coefficient determined based on fluid characteristics, Indicates the opening area of ​​the expansion valve, Indicates the circuit pressure drop, Indicates Temperature difference of the circuit;

[0122] The Lagrange multiplier method is used to solve the objective function and obtain the optimal Corresponding and , the specific steps include:

[0123] Calculate the gradient of the objective function ;

[0124] Adjustment by gradient descent and Reduce the objective function value.

[0125] In each iteration, according to the current Recalculate temperature difference and load , and update and until it converges to the optimal value.

[0126] Furthermore, in step S2, the dynamic refrigerant distribution method further includes:

[0127] Based on real-time monitoring of load and temperature difference The control target is updated through the feedback mechanism:

[0128] ,in represents the specific heat capacity of the refrigerant, No. The mass flow rate of the loop, denote the circuit inlet and outlet temperatures respectively;

[0129] Dynamically adjust the weight coefficients using an adaptive adjustment mechanism based on multivariable control , so that the system maintains the optimal performance state under different working conditions. This process uses the Bayesian optimization algorithm to gradually approach the global optimal solution through iterative experiments. The Bayesian optimization formula is:

[0130] ,in represents the expected value of the objective function;

[0131] Specifically, the dynamic refrigerant distribution mechanism is one of the cores of this control method. By installing real-time monitoring equipment in each refrigeration circuit, the operating status of each circuit can be accurately grasped, including real-time data such as temperature, pressure, and flow. The control system is based on real-time data, combined with the current load and temperature difference requirements, and uses adjustable electronic expansion valves and refrigerant distributors to dynamically adjust the refrigerant flow. This adjustment method based on the optimization control objective function provides the best cooling effect for each refrigeration circuit, which not only meets the load requirements, but also significantly improves the system efficiency. Under complex and changeable working conditions, the refrigerant flow can be accurately controlled to reduce energy consumption.

[0132] Step S3, intelligent circuit startup and load adjustment, adjusts the startup sequence and operating frequency of the refrigeration circuit according to the current load situation and temperature difference requirements; under low load conditions, only one circuit is selected to operate; under high load conditions, the two circuits work together, making full use of the advantages of the reverse flow design. By coordinating with the dynamic refrigerant distribution in step S2, the system can avoid the problem of load imbalance between circuits, thereby improving the overall energy efficiency;

[0133] The intelligent loop startup and load adjustment method in step S3 is:

[0134] Define real-time monitoring parameters, including: current system total load demand , target temperature difference , No. Real-time refrigerant flow rate of the circuit , specific heat capacity of refrigerant , No. Circuit inlet temperature , No. Circuit outlet temperature , and Mass flow rate of the loop ;

[0135] To perform a total load calculation: ,in, is the number of loops, is the refrigerant flow rate of each circuit;

[0136] Assign loop priorities and define priority functions , determines the startup order of the circuit:

[0137] ,in and Represents the weight coefficient, adjusting the impact of temperature difference and load on priority, Indicates The temperature difference of the circuit, Indicates The load contribution of the circuit;

[0138] according to The values ​​are sorted from large to small, and the circuit with the highest priority is started first.

[0139] Defining the start threshold : ,in and Indicates the adjustment coefficient, balancing the influence of load and temperature difference, Indicates the maximum load capacity of the system. Indicates the maximum temperature difference that the system can achieve;

[0140] When the priority of a circuit Exceeding the threshold , start the circuit.

[0141] For the activated circuit , adjust its operating frequency Matching system requirements:

[0142] ,in represents the fundamental frequency of the loop, Indicates the frequency adjustment coefficient, which controls the frequency change amplitude;

[0143] Perform load balancing and dynamic adjustment, and define load balancing indicators :

[0144] ,in Indicates the total refrigerant flow rate of the system;

[0145] when Exceeding a certain threshold When the load is balanced, the frequency or flow of the circuit is dynamically adjusted;

[0146] Dynamic adjustment method: real-time monitoring , change the opening of the expansion valve according to the system response and the setting value of the refrigerant distributor To achieve the refrigerant flow and operating frequency Fine-tuning.

[0147] Using a closed-loop feedback mechanism, real-time monitoring and changes, including and Dynamic adjustment of internal parameters:

[0148] Define the overall optimization objective function :

[0149] ,in Indicates The efficiency of the circuit, Indicates the temperature difference adjustment weight, balancing energy consumption and temperature difference effect;

[0150] Gradient descent method and genetic algorithm are used to gradually adjust the frequency and flow of the loop to achieve the optimal performance of the system as a whole;

[0151] Perform system stability and preventive adjustments, and regularly calculate system stability indicators :

[0152] ,when Early warning when exceeding the set range;

[0153] Based on historical data and prediction models, possible load peaks are estimated, and additional circuits are started in advance or the frequency of existing circuits is adjusted to ensure stable system operation;

[0154] Specifically, the intelligent loop startup and load adjustment strategy enables the system to flexibly respond to different load demands and temperature difference changes. By real-time monitoring of the system's total load demand and temperature difference target, the system intelligently determines the startup sequence and operating frequency of each loop; when the load is low, only the necessary loops are operated to save energy; when the load is high, the two loops work together, making full use of the advantages of the reverse flow design to ensure balanced system load distribution, avoiding the common load imbalance problem in traditional systems, not only improving overall energy efficiency, but also extending the service life of the equipment.

[0155] Step S4, load adaptation and large temperature difference adjustment, optimizing the distribution of refrigerant and the coordinated control of the circuit, and providing the maximum temperature difference effect under special needs;

[0156] In applications such as tunnel cooling or special industrial cooling, the working state of the circuit is automatically optimized through analysis and adjustment of real-time monitoring data, so that the temperature difference always reaches the optimal value and avoids unnecessary energy consumption increase;

[0157] Load adaptation and large temperature difference regulation methods include:

[0158] Continuous monitoring of system parameters, including real-time data of each refrigeration circuit, as well as external environmental conditions (temperature and humidity in the tunnel);

[0159] Use historical data and current monitoring data for analysis to identify current system load conditions and temperature difference requirements;

[0160] The analysis includes identifying load peaks and temperature demand trends;

[0161] Identify special requirements in the current application scenario, including the need for a larger temperature difference during a certain period of time to cope with the sharp rise in temperature in the tunnel;

[0162] Automatically set new temperature difference targets and load distribution strategies based on identified demand;

[0163] Select the circuit that can provide the largest temperature difference effect, and shut down or reduce the operating frequency of other circuits as needed;

[0164] By optimizing the coordination between circuits, the distribution of refrigerant in each circuit is more balanced and efficient;

[0165] In step S4, dynamic adjustment and real-time response are performed:

[0166] Based on real-time monitoring data, the system dynamically adjusts the refrigerant distribution and circuit working status; temporarily increases the refrigerant flow or working frequency of certain circuits when the load suddenly increases;

[0167] The system automatically adjusts the working mode of the loop by balancing the relationship between the temperature difference target and energy consumption; when the temperature difference demand decreases, the system will reduce the working frequency of some loops or close some loops;

[0168] The system continuously monitors the load distribution of each circuit to ensure that the refrigerant distribution is balanced among the circuits;

[0169] Specifically, load adaptation and large temperature difference regulation are suitable for application scenarios that require large temperature difference effects, such as tunnel cooling or special industrial cooling. The system continuously monitors external environmental conditions and internal operating status, automatically identifies special needs, and dynamically adjusts the distribution of refrigerants and the working status of the circuits. This enables the system to quickly increase cooling capacity when the load increases suddenly, and reduce unnecessary energy consumption when the demand decreases, thereby achieving the best balance between energy efficiency and temperature difference. By optimizing the collaborative work between circuits, the system further enhances its performance under high temperature difference requirements, and can stably achieve the expected temperature difference effect even under the most demanding conditions.

[0170] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A control system for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, characterized in that: include: The hot and cold air unit comprises a first compressor, a second compressor, a first evaporator, a second evaporator, a first condenser, a second condenser, a fan, an electronic expansion valve and a filter. A plurality of refrigeration circuits are arranged in the hot and cold air unit. The evaporator and the condenser in the hot and cold air unit are arranged in a cross arrangement. A data acquisition module, including a temperature sensor, a pressure sensor, a flow sensor and a data acquisition device, the data acquisition module acquires real-time data of each refrigeration circuit through the sensor and the data acquisition device; Dynamic refrigerant distribution and regulation module, which uses a control algorithm to dynamically adjust the refrigerant flow of each refrigeration circuit based on real-time data, and has a built-in refrigerant distributor, which cooperates with the electronic expansion valve in the hot and cold air unit; Intelligent loop management module, which controls the start-up sequence and operating frequency of each refrigeration loop according to the current load and temperature difference requirements of the control system. The intelligent loop management module includes a loop start controller, a load analysis unit and a loop frequency controller; In the intelligent loop management module, load regulation is performed, and the specific steps include: Assume total load demand , target temperature difference , No. Real-time refrigerant flow rate of the circuit , specific heat capacity of refrigerant , No. Circuit inlet temperature , No. Circuit outlet temperature , and Mass flow rate of the loop ; Calculate the total load: ,in, Indicates the number of loops; Assign loop priorities and define priority functions Determine the circuit startup sequence: ,in and represents the weight coefficient, Indicates The temperature difference of the circuit, Indicates The load of the circuit; according to Sort the values ​​from large to small, and start the circuit with the highest ranking first; The load regulation step further includes: Defining the start threshold , expressed as: ,in and represents the adjustment coefficient, Indicates the maximum load capacity, Indicates the maximum temperature difference that can be achieved; When the priority of a circuit Exceeding the threshold When , start the circuit; For the activated circuit , adjust its operating frequency Matching system requirements: ,in represents the fundamental frequency of the loop, represents the frequency adjustment coefficient; Perform load balancing and dynamic adjustment, and define load balancing indicators : ,in Indicates the total refrigerant flow; Preset Threshold ,when Exceeding the threshold When , the operating frequency of the loop is dynamically adjusted; Using a closed-loop feedback mechanism, real-time monitoring and changes, including and Dynamic adjustment of internal parameters: Define the overall optimization objective function : ,in Indicates The efficiency of the circuit, Indicates the temperature difference adjustment weight, balancing energy consumption and temperature difference effect; Gradient descent method and genetic algorithm are used to adjust the frequency and flow of the loop; The load adaptation and large temperature difference adjustment module adjusts the refrigerant distribution and the working status of the refrigeration circuit based on real-time data. It is used in scenarios with large temperature differences, that is, scenarios with temperature differences exceeding 5°C. In the load adaptation and large temperature difference adjustment module, the steps of adjusting the refrigerant distribution and the working state of the refrigeration circuit are as follows: Continuously monitor operating parameters, including real-time data for each refrigeration circuit, as well as external environmental conditions; Use historical data, current real-time data, and external environmental conditions to analyze the current load situation and temperature difference requirements, and identify whether there are special requirements in the current scenario, that is, a temperature difference requirement of more than 5°C; After identifying special needs, the loop startup and load adjustment method in the load adjustment step is used to set new temperature difference targets and load distribution strategies.

2. The control system of a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit according to claim 1, characterized in that: In the cold and hot air unit, the filter is at the return air position, the first evaporator, the first compressor, the first condenser and the electronic expansion valve are connected in series in sequence to form a first refrigeration circuit, and the second evaporator, the second compressor, the second condenser and the electronic expansion valve are connected in series in sequence to form a second refrigeration circuit; The connection end between the first compressor and the first evaporator is located at the air outlet of the first evaporator, the connection end between the first compressor and the first condenser is located at the air inlet of the first condenser, the connection end between the electronic expansion valve and the first evaporator is located at the liquid inlet of the first evaporator, the connection end between the electronic expansion valve and the first condenser is located at the liquid outlet of the first condenser, the first refrigeration circuit and the second refrigeration circuit are arranged crosswise, the first evaporator and the second evaporator are placed vertically and front to back according to the airflow direction, the second evaporator is close to the return air outlet, the first condenser and the second condenser are placed vertically and front to back according to the airflow direction, and the first condenser is close to the return air outlet; The cold and hot air unit also includes an air outlet, and the fan is placed at the air outlet. The air outlet on the evaporator side is the cold air outlet, and the air outlet on the condenser side is the hot air outlet.

3. A control method for a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit, characterized in that: A control system using a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit as claimed in any one of claims 1 to 2 comprises the following steps: Step S1, dual-circuit series counter-flow deployment, using dual refrigeration circuits in series counter-flow to deploy the hot and cold air units, with the refrigerants of the two refrigeration circuits flowing in opposite directions; Step S2, dynamic refrigerant distribution, monitoring and collecting real-time data of each refrigeration circuit; Step S3, intelligent circuit startup and load adjustment, according to the current load conditions and temperature difference requirements, adjust the startup sequence and operating frequency of the refrigeration circuit, only operate one circuit under low load conditions, and work together under high load conditions; Step S4, load adaptation and large temperature difference adjustment, adjusts the refrigerant distribution and the working state of the refrigeration circuit under the large temperature difference scenario.

4. The control method of a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit according to claim 3, characterized in that: In step S2, the refrigerant flow rate is dynamically adjusted using the electronic expansion valve and the refrigerant distributor according to the real-time data in combination with the current load and temperature difference requirements.

5. The control method of a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit according to claim 4, characterized in that: The dynamic refrigerant distribution method in step S2 is: Carry out data collection. The data collected here include: real-time temperature , real-time pressure , real-time refrigerant flow ,load , target temperature difference and The efficiency of the circuit ; Construct an objective function to adjust the refrigerant flow rate of each refrigeration circuit , the objective function is: ,in: represents the weight coefficient, Indicates the maximum pressure within the tolerable range. Indicates the total number of circuits; Based on the objective function, the gradient descent method is used to adjust the opening of the electronic expansion valve and the setting value of the refrigerant distributor , refrigerant flow adjustment method: ,in represents the flow coefficient, Indicates the opening area of ​​the expansion valve, Indicates the circuit pressure drop, Indicates Temperature difference of the circuit; The Lagrange multiplier method is used to solve the objective function and obtain the optimal Corresponding and , the solution steps include: Calculate the objective function gradient , adjusted by gradient descent and Reduce the objective function value; Iterate, and in each iteration, according to the refrigerant flow Recalculate temperature difference and load , and update and until it converges to the optimal value.

6. The control method of a dual refrigeration circuit series reverse flow large temperature difference cold and hot air unit according to claim 5, characterized in that: In step S2, the dynamic refrigerant distribution method further includes: Based on real-time monitoring of load and temperature difference The control target is updated through the feedback mechanism: ,in represents the specific heat capacity of the refrigerant, No. The mass flow rate of the loop, denote the circuit inlet and outlet temperatures respectively; Using Bayesian optimization algorithm to adjust the weight coefficient of the objective function .

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