Heat source tower system, refrigerating system and circulating fluid flow control method

Abstract

The invention discloses a heat source tower system, a refrigerating system and a circulating fluid flow control method.The heat source tower system comprises a draught fan, a filler layer, a sprayer, a spraying pipe, a storage tank, a two-loop pipeline system and a circulating pump, the two-loop pipeline system comprises a pipeline a, a pipeline b and a backflow pipeline, and the pipeline a and the pipeline b are connected between the storage tank and the backflow pipeline in parallel; a cooling device for cooling circulating liquid in the pipeline is arranged on the pipeline a; the temperature of the circulating fluid in the backflow pipeline is adjusted by adjusting the flow of the pipeline a and the pipeline b and the temperature of the circulating fluid in the pipeline a; and the circulating pump is used for conveying the circulating liquid in the backflow pipeline to the backflow pipeline and circulating the circulating liquid to the spraying pipe. The system can flexibly adapt to different load requirements, dynamically adjusts the flow ratio of the pipeline a to the pipeline b, has the advantages of efficient cooling and energy-saving operation, and is suitable for the field of air conditioning systems and industrial cooling.

Description

Technical Field

[0001] The present invention relates to a control method and system for the circulating liquid of a heat source tower, and particularly to a flow distribution optimization system based on a dynamic control strategy, which can dynamically adjust the flow ratio of two loops according to the actual load demand, and belongs to the fields of thermal engineering and automatic control. Background Art

[0002] As an efficient heat and moisture exchange device, the heat source tower is widely used in air conditioning systems and industrial cooling fields. It realizes the transfer and dissipation of heat through the heat and moisture exchange between the circulating liquid and the air, and has the characteristics of simple structure and stable operation. However, under the existing technical conditions, the design of the heat source tower faces various limitations in practical applications, especially in the operation under low temperature environment in winter, and deficiencies in flow control and system energy consumption optimization are exposed.

[0003] The circulating liquid of traditional heat source towers usually operates in a fixed flow mode, that is, the liquid in the storage tank returns through a single pipeline. Although this design has a simple structure, it is extremely passive under the condition of dynamic change of load demand. On the one hand, when the load demand is high, due to the too high return temperature of the liquid, the cooling capacity is insufficient, and it cannot meet the heat dissipation requirements of the air conditioning unit for chilled water or cooling water; on the other hand, when the load demand is low, the temperature of the circulating liquid is too low after being processed by the cooling device, resulting in waste of energy and lack of energy-saving optimization ability.

[0004] At the same time, there are also obvious deficiencies in the flexibility of flow distribution and control strategy in the existing technology. The common flow distribution methods are mostly fixed adjustments of mechanical valves, and the flow ratio cannot be dynamically adjusted according to the real-time working conditions. In addition, the traditional system lacks the feedback and comprehensive utilization of key parameters such as liquid temperature and air conditioning load data, resulting in low flow control accuracy and poor comprehensive energy efficiency of the system.

[0005] In addition, in the low temperature environment in winter, the circulating liquid of the heat source tower usually uses antifreeze to avoid freezing. The thermodynamic properties (such as specific heat capacity, viscosity, etc.) of antifreeze are different from those of water, which limits the performance of the existing heat source tower under low temperature conditions. The cooling treatment of the circulating liquid often cannot be effectively matched according to the actual load demand, further exacerbating the waste of energy.

[0006] In view of the above problems, there is an urgent need for a heat source tower flow distribution method and system based on a dynamic control strategy, which can combine the load demand of the air conditioning unit and the liquid temperature feedback to dynamically adjust the flow ratio of the circulating liquid, and while meeting the cooling effect, achieve energy-saving operation, thereby effectively improving the comprehensive energy efficiency of the heat source tower. Summary of the Invention

[0007] Objective of the Invention: The present invention aims to solve the problems of fixed flow distribution, lack of dynamic control strategy, and serious energy waste in existing heat source towers under dynamic load demands. It provides a heat source tower system, a refrigeration system, and a circulating fluid flow control method. By real-time feedback of the load demand of the air conditioning unit and the temperature of the circulating liquid, the flow distribution ratio of the circulating liquid is dynamically adjusted to achieve energy-saving effects while meeting the cooling demand, and significantly improve the comprehensive energy efficiency of the heat source tower.

[0008] Technical Solution: To achieve the above objective of the invention, the following technical solutions are adopted:

[0009] The present invention first provides a heat source tower system, including:

[0010] A fan for providing air circulation;

[0011] A sprayer and a spray pipe. The sprayer is arranged on the spray pipe for spraying the circulating liquid;

[0012] A heat exchange layer is arranged below the sprayer; the sprayer sprays the circulating liquid onto the heat exchange layer; the heat exchange layer is used for heat exchange between the cooling water or chilled water of the air conditioning unit and the circulating liquid;

[0013] A storage tank for collecting the circulating liquid after heat exchange and providing a liquid source for subsequent circulation;

[0014] A two-loop pipeline system, including an a pipeline, a b pipeline, and a return pipeline. The a pipeline and the b pipeline are connected in parallel between the storage tank and the return pipeline; a cooling device for cooling the circulating liquid in the pipeline is arranged on the a pipeline; the two-loop pipeline system adjusts the temperature of the circulating fluid in the return pipeline by adjusting the flow sum of the a pipeline and the b pipeline and the temperature of the circulating fluid in the a pipeline;

[0015] A circulation pump is arranged on the return pipeline for circulating the circulating liquid through the return pipeline to the spray pipe.

[0016] The return pipeline is used for returning the circulating liquid to the sprayer for circulation.

[0017] An air conditioning unit is connected to the heat source tower system. Its cooling water or chilled water is precooled or heat-exchanged through the packing layer and then enters the unit to improve the overall heat exchange efficiency and optimize energy consumption.

[0018] The present invention also provides a refrigeration system, including:

[0019] The above-provided heat source tower system;

[0020] An air conditioning unit;

[0021] Circulating liquid that circulates between the heat source tower system and the air conditioning unit.

[0022] The present invention also provides a method for controlling the circulating fluid flow rate of the above refrigeration system, including:

[0023] Based on the load demand of the air-conditioning unit, calculate the target temperature T that meets the load requirement target ;

[0024] According to the target temperature and the feedback data of the temperature sensor, adjust the flow rate ratio of pipeline a and pipeline b:

[0025]

[0026] Where: Q a and Q b are the flow rates of pipeline a and pipeline b respectively; T a and T b are the outlet temperatures of pipeline a and pipeline b respectively; T target is the target temperature that meets the load requirement.

[0027] The heat source tower structure of the present invention includes a fan, a sprayer, a packing layer, a storage tank, a circulation pump, a three-way valve, a temperature sensor and a two-loop pipeline system. After the circulating liquid (antifreeze in winter) is collected in the storage tank, it is split into pipeline a and pipeline b through the three-way valve. Among them: Pipeline a: The liquid passes directly without cooling treatment and directly returns to the storage tank; Pipeline b: The liquid is cooled by a cooler and then returns to the storage tank; The liquids in the two pipelines are mixed before returning to the storage tank, and the mixed liquid is sent back to the spray pipe through the circulation pump via the return pipeline, and then the next operation of the circulating liquid is carried out by the sprayer.

[0028] The control strategy is to adopt a dynamic flow distribution strategy based on feedback control to achieve precise adjustment of the flow rates of the two pipelines. Specifically, it includes the following steps: Feedback acquisition: The temperature sensor is used to monitor the initial temperature of the liquid in the storage tank and the temperature of the liquid after mixing in the two pipelines in real time, and at the same time obtain the load demand of the air-conditioning unit (such as the temperature and flow rate of chilled water or cooling water). Target calculation: The control unit combines the load demand to calculate the target temperature of the circulating liquid. Flow distribution: Based on the target temperature and the actual temperature of the circulating liquid, dynamically calculate the flow distribution ratio of pipeline a and pipeline b. When the load demand is high, all the flow is introduced into pipeline b to achieve deep cooling through the cooler; when the load demand is low to medium, by adjusting the flow rate ratio of the two pipelines, the cooling effect is ensured while reducing energy consumption. Execution control: The control unit sends an adjustment signal to the three-way valve to dynamically distribute the circulating liquid flow rates of the two pipelines.

[0029] Beneficial effects: By dynamically adjusting the flow distribution of the two circuits of the heat source tower, the present invention realizes the matching of load demand and energy-saving optimization. Compared with the prior art, the present invention has the following advantages: (1) Improving system adaptability: It can flexibly adjust the flow ratio of the two pipelines according to the real-time load demand, ensuring that the cooling demand is met under high load and optimizing energy consumption under low load. (2) Enhancing control accuracy: Based on the feedback control strategy, it collects the liquid temperature and load demand data in real time, dynamically adjusts the flow ratio, and precisely controls the mixing temperature of the circulating liquid. (3) Achieving energy-saving goals: By dynamically distributing the flow of pipeline a and pipeline b, while meeting the cooling demand, unnecessary cooling treatment is avoided, and energy consumption is reduced. (4) Strengthening system stability: Under extreme working conditions (such as low temperature in winter and high load demand), the heat exchange method is dynamically adjusted, and through the dual effects of heat exchange in the packing layer + evaporative cooling, it ensures that the chilled water can maintain an appropriate temperature under any working conditions. Brief Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the present invention;

[0031] Figure 2 is a schematic diagram of the mixing process of the circulating liquid of the present invention;

[0032] Figure 3 is a framework diagram of the control strategy of the present invention;

[0033] Among them, 1. Fan, 2. Solution absorber, 3. Sprayer, 4. Spray pipe, 5. Heat exchange layer, 6. Air inlet, 7. Overflow pipe, 8. Make-up pipe, 9. Storage tank, 10. Liquid outlet pipe, 11. Circulation pump, 12. Chiller, 13. Three-way valve, 14. Temperature sensor, 15. Return pipeline, 16. Pipeline a, 17. Pipeline b, 18. Mixing port. Detailed Embodiments

[0034] The heat source tower system of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The present invention realizes the optimized control of the flow distribution of the heat source tower through a dynamic control strategy, and achieves an energy-saving effect on the premise of meeting the load demand.

[0035] As Figure 1 shown, the heat source tower system of the present invention includes the following components: Fan 1 provides a forced air flow, enabling the air to exchange heat with the circulating liquid through the heat exchange layer 5; The sprayer 3 and the spray pipe 4 are used to evenly spray the circulating liquid into the packing layer of the heat exchange layer 5, increasing the heat and moisture exchange area. The cooling water or chilled water of the air conditioning unit passes through the packing layer, pre-cools or exchanges heat with the heat exchanger in the packing layer and then enters the unit; The storage tank 9 is used to collect the circulating liquid flowing down after spraying, serving as the liquid source for subsequent circulation.

[0036] The heat exchanger in the heat exchange layer 5 can adopt a coil pipe.

[0037] The heat source tower system also includes a three-way valve 13, which is arranged at the outlet of the storage tank 9 and is used to divert the circulating liquid to the a pipeline 16 and the b pipeline 17. The liquid in the a pipeline 16 passes directly without cooling treatment; the liquid in the b pipeline 17 is cooled by the cooler 12 and then refluxed. The liquids in the two pipelines are mixed at the mixing port 18 of the reflux pipeline, and are sent to the reflux pipeline by the circulation pump 11, and circulated to the spray pipe.

[0038] The temperature sensors 14 are respectively arranged at the storage tank 9, the outlet of the b pipeline 17 and the mixing port 18, and are used to monitor the initial temperature, the temperature after cooling and the temperature after mixing of the liquid in real time. The control unit receives the feedback signal of the temperature sensor 14 and the load demand data of the air conditioning unit, dynamically adjusts the opening of the three-way valve 13, and optimizes the flow distribution of the a pipeline 16 and the b pipeline 17.

[0039] In addition to being connected to the storage tank 9 through the three-way valve 13, the a pipeline 16 and the b pipeline 17 can also be directly connected to the storage tank 9, and a regulating valve is set on each pipeline to adjust the flow of the a pipeline 16 and the b pipeline 17. The following is only an explanation of the connection mode of the three-way valve.

[0040] The liquid inlet 19 and the liquid outlet 20 are arranged in the packing layer and the coil heat exchange system inside it, and are used to realize the heat exchange process of the cooling water or chilled water of the air-conditioning unit. The liquid inlet 19 is connected to the chilled water or cooling water pipeline of the air-conditioning unit, and the high-temperature chilled water or cooling water is introduced into the coil inside the packing layer. The coil inside the packing layer serves as a heat exchange medium, and the chilled water or cooling water flows in the coil. At the same time, the circulating liquid outside the coil has been cooled by the fan 1 and the sprinkler 3. When the chilled water / cooling water flows in the coil, it indirectly exchanges heat with the circulating liquid cooled by the packing layer, so that the temperature of the chilled water / cooling water is reduced, and the circulating liquid takes away the heat and continues to flow back to the storage tank 9. The cooling water or chilled water after heat exchange flows out through the liquid outlet 20 and is transported to the air-conditioning unit to meet the load demand of the air-conditioning system.

[0041] The system operation process includes three steps: diversion and mixing, data collection and feedback, and dynamic adjustment; Step 1 (diversion and mixing): The circulating liquid in the storage tank 9 is diverted to pipeline a 16 and pipeline b 17 through the three-way valve 13. The liquid in pipeline a 16 returns directly to the mixing port 18, while the liquid in pipeline b 17 returns to the mixing port 18 after being cooled by the cooler 12. After the liquids in the two pipelines are fully mixed at the mixing port 18, they are sent to the reflux pipe through the circulation pump 11 and circulated to the spray pipe. Step 2 (data collection and feedback): The temperature sensor 14 monitors the initial temperature T of the liquid in the storage tank 9 initial , b. The temperature of the liquid at the outlet of pipeline 17 after cooling T b The liquid mixing temperature T of the mixing port 18mix Meanwhile, the control unit obtains real-time load demand data from the air conditioning unit, including the target mixed temperature T target and the chilled water flow demand. Step 3 (Dynamic regulation): Based on the feedback data of the temperature sensor and the load demand, the control unit dynamically adjusts the opening ratio of the three-way valve 13 to regulate the flow rates Q a and Q b of the a-pipe 16 and the b-pipe 17 to ensure that the temperature T mix of the mixed liquid reaches the target temperature T target .

[0042] The control strategy of the present invention is based on real-time feedback and dynamic optimization, specifically including mixed temperature calculation, flow rate ratio calculation, dynamic load regulation, and control logic framework.

[0043] Mixed temperature calculation formula: The actual temperature T mix of the mixed liquid is calculated by the following formula:

[0044]

[0045] Where: T a and T b are the outlet temperatures of the a-pipe 16 and the b-pipe 17 respectively; Q a and Q b are the flow rates of the a-pipe 16 and the b-pipe 17 respectively.

[0046] Flow rate ratio calculation formula: The control unit dynamically adjusts the flow rate ratio Q target / Q initial of the a-pipe 16 and the b-pipe 17 according to the target mixed temperature T a / Q b . The optimization formula for flow rate distribution is as follows:

[0047]

[0048] Where: T target is the target temperature to meet the load requirement, and this formula ensures that the actual temperature T mix of the mixed liquid is close to the target temperature T target .

[0049] Dynamic load regulation is divided into high load condition and low load condition according to the operating conditions.

[0050] High load condition: When the air conditioning unit requires greater cooling capacity, the control unit adjusts the three-way valve 13 to fully open the b-pipe 17, that is, Q a = 0, Q b = Q total Q totalFor the total value that can be allowed for the flow rate, ensure that the circulating liquid achieves the maximum cooling effect.

[0051] Low load condition: When the cooling load is low, the control unit increases the flow rate ratio Q of pipeline 16 of a a , reduces the cooling treatment amount of pipeline 17 of b, thereby reducing energy consumption.

[0052] The control logic is the core of the present invention. By means of a dynamic control strategy, the flow rate ratio of the circulating liquid is optimized and adjusted, so as to achieve precise control of the target temperature of the reflux circulating liquid. The entire control process is based on real-time feedback and load demand, and adopts a combination of calculation and execution for dynamic regulation.

[0053] First of all, the control unit collects the feedback data of the temperature sensor 14 in real time, including the initial temperature T of the circulating liquid in the storage tank 9 initial , the outlet temperature T of pipeline 16 of a a , the outlet temperature T of pipeline 17 of b b and the actual mixing temperature T of the liquid at the mixing port 18 mix . At the same time, the control unit receives the load demand signal from the air conditioning unit, and the load demand signal includes the target mixing temperature T target and the real-time flow rate demand of chilled water or cooling water.

[0054] The control unit first calculates the target temperature T of the mixed liquid target to meet the operation requirements of the air conditioning unit. The calculation of the target temperature T of the mixed liquid target belongs to the conventional technology in this field and will not be described here. Combining the real-time collected temperature data, the control unit calculates the actual temperature T of the current mixed liquid according to the following formula mix :

[0055]

[0056] where Q a and Q b are the flow rates of pipeline 16 of a and pipeline 17 of b respectively, and T a and T b are the outlet temperatures of pipeline 16 of a and pipeline 17 of b respectively. This formula is used to dynamically evaluate the deviation between the current mixing temperature and the target temperature.

[0057] When the actual temperature T of the mixed liquid mix deviates from the target temperature T target , the control unit dynamically adjusts the flow rate ratio of pipeline 16 of a and pipeline 17 of b based on the following formula:

[0058]

[0059] Through this formula, the control unit calculates the required flow rate ratio Q a / Q b to ensure that the temperature T of the mixed liquid mix is close to the target temperature T target . Among them, if T target is close to T b , the flow rate of pipeline b17 will be preferentially increased; if T target is close to T a , the flow rate of pipeline a16 will be preferentially increased.

[0060] After the calculation is completed, the control unit sends a control command to the three-way valve 13 according to the calculation result, dynamically adjusts the opening of the three-way valve 13, so as to adjust the flow distribution of pipeline a16 and pipeline b17. Specifically, when the load of the air-conditioning unit is high, the control unit adjusts the three-way valve 13 to fully open pipeline b17, that is, all the circulating liquid passes through pipeline b17 and is cooled by the cooler 12 to ensure the maximum cooling effect; when the load of the air-conditioning unit is low, the control unit appropriately increases the flow rate ratio of pipeline a16 and reduces the cooling treatment amount of pipeline b17 to achieve energy-saving operation.

[0061] While adjusting the flow rate ratio, the temperature sensor 14 continuously monitors the mixing temperature T of the mixing port 18 mix . The control unit compares the deviation value between the mixing temperature T mix and the target temperature T target . If the deviation value exceeds the set threshold, the flow rate ratios of pipeline a16 and pipeline b17 are recalculated, and the opening of the three-way valve 13 is adjusted in real time until the actual temperature T of the mixed liquid mix reaches the target temperature T target .

[0062] The entire control process is carried out in a cyclic form, that is, the control unit collects data in real time, calculates the flow rate ratio, executes the flow rate adjustment and collects data again, and realizes the precise control of the mixing temperature of the circulating liquid through the feedback loop. Through dynamic adjustment, the system can adapt to the changes of different load conditions of the air-conditioning unit, so as to minimize the system energy consumption while meeting the cooling requirements.

Claims

1. A heat source tower system, characterized in that: include: A fan (1) for providing air circulation; A sprayer (3) and a spray pipe (4), wherein the sprayer (3) is arranged on the spray pipe for spraying circulating liquid; A heat exchange layer (5) is arranged below the sprayer; the sprayer sprays the circulating liquid onto the heat exchange layer (5); the heat exchange layer (5) is used for heat exchange between cooling water or chilled water of the air conditioning unit and the circulating liquid; A storage tank (9) is used to collect circulating liquid after heat exchange and provide a liquid source for subsequent circulation; A two-circuit pipeline system comprises an a pipeline (16), a b pipeline (17) and a return pipeline, wherein the a pipeline (16) and the b pipeline (17) are connected in parallel between a storage tank (9) and the return pipeline; a cooling device for cooling the circulating liquid in the pipeline is arranged on the a pipeline (16); the two-circuit pipeline system adjusts the temperature of the circulating fluid in the return pipeline by adjusting the flow rates of the a pipeline (16) and the b pipeline (17) and the temperature of the circulating fluid in the a pipeline (16); A circulation pump (11) is arranged on the return pipe and is used to circulate the circulating liquid to the spray pipe through the return pipe.

2. The heat source tower system according to claim 1, characterized in that: The flow separation and confluence pipe network further comprises a three-way valve (13), one port of the three-way valve (13) is connected to the outlet of the storage tank (9); the a pipeline (16) and the b pipeline (17) are connected to the two outer ports of the three-way valve; and the flow rates of the a pipeline (16) and the b pipeline (17) are adjusted by the three-way valve (13).

3. The heat source tower system according to claim 1 or 2, characterized in that: Temperature sensors (14) are provided at the storage tank (9), the outlet of the b pipeline (17) and the return pipeline, and are used to monitor the temperature of the circulating liquid at three locations of the storage tank (9), the outlet of the b pipeline (17) and the return pipeline; and the flow rates of the a pipeline (16) and the b pipeline (17) are adjusted according to the monitored temperatures of the circulating liquid at two locations of the storage tank (9), the outlet of the b pipeline (17) and the return pipeline.

4. The heat source tower system according to claim 3, characterized in that: The flow distribution of pipeline a (16) and pipeline b (17) is as follows: Where: Q a and Q b are the flow rates of pipeline a (16) and pipeline b (17) respectively; T a and T b are the outlet temperatures of pipeline a (16) and pipeline b (17) respectively; T target The target temperature to meet the load requirements.

5. The heat source tower system according to claim 4, characterized in that: The flow distribution of pipeline a (16) and pipeline b (17) is controlled by a control unit, and the control steps of the control unit include: Based on the load demand of the air conditioning unit, calculate the target temperature T that meets the load requirements target ; According to the target temperature and feedback data from the temperature sensor (14), the opening of the three-way valve (13) is dynamically adjusted to adjust the flow ratio of pipeline a (16) and pipeline b (17); when the load demand is high, all the liquid passes through pipeline b (17) to achieve the maximum cooling effect; when the load demand is low to medium, the flow ratio of pipeline a (16) and pipeline b (17) is dynamically allocated to meet the target temperature and reduce energy consumption.

6. The heat source tower system according to claim 5, characterized in that: The control unit comprises: A feedback module, used for collecting data from a temperature sensor (14) in real time; A calculation module, used for calculating the flow ratio of pipeline a (16) and pipeline b (17) based on the collected data; The execution module is used to control the opening of the three-way valve (13) to achieve dynamic flow distribution between the two pipelines.

7. The heat source tower system according to claim 1, characterized in that: The heat exchange layer (5) comprises a packing layer and a heat exchanger arranged in the packing layer; the heat exchanger has a liquid inlet (19) and a liquid outlet (20); the liquid inlet (19) is used to transport cooling water or chilled water from the air conditioning unit to enter the heat exchanger in the packing layer to exchange heat with the circulating liquid to reduce the temperature of the cooling water or chilled water; the liquid outlet (20) is used to transport the cooling water or chilled water after heat exchange in the coil in the packing layer to the air conditioning unit to meet the load demand of the air conditioning system and improve the heat exchange efficiency and the overall energy efficiency of the system.

8. A refrigeration system, characterized in that: include: The heat source tower system according to any one of claims 1 to 7; Air conditioning units; The cooling water or chilled water of the air-conditioning unit exchanges heat with the circulating liquid of the heat source tower system in the heat exchange layer.

9. The circulating fluid flow control method of the refrigeration system according to claim 8, characterized in that: include: Based on the load demand of the air conditioning unit, calculate the target temperature T that meets the load requirements target ; According to the target temperature and the feedback data of the temperature sensor (14), the flow ratio of the a pipeline (16) and the b pipeline (17) is adjusted: Where: Q a and Q b are the flow rates of pipeline a (16) and pipeline b (17) respectively; T a and T b are the outlet temperatures of pipeline a (16) and pipeline b (17) respectively; T target The target temperature to meet the load requirements.

10. The circulating fluid flow control method according to claim 9, characterized in that: According to the opening of the three-way valve, the flow ratio of pipeline a (16) and pipeline b (17) is adjusted; when the load demand is high, all the liquid passes through pipeline b (17) to achieve the maximum cooling effect; when the load demand is low to medium, the flow ratio of pipeline a (16) and pipeline b (17) is dynamically allocated to meet the target temperature and reduce energy consumption.

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