Composite cold and heat source and control system

Abstract

The invention discloses a composite cold and heat source and a control system, and particularly relates to the field of optimal control of heating, ventilation and air conditioning systems. An air source heat pump, a ground source heat pump, a solar heat collection device, an electric boiler and an intelligent control system of the electric boiler are integrated in a dynamically-adjustable multi-energy combined operation system; intelligent adaptation and efficient utilization of different seasons, load changes and environmental parameters are realized; the ground source heat pump and the air source heat pump serve as main cold and heat source equipment, the solar heat collection device and the electric boiler serve as supplementary and emergency heat sources, and intelligent control is achieved through the upper computer and the PLC control cabinet. The system is optimally designed under typical working conditions in northern cold regions: in summer operation, the ground source heat pump is preferentially adopted for cooling, and the COP of the ground source heat pump is relatively high due to relatively stable underground temperature, so that the electric energy consumption can be effectively reduced, the refrigeration requirement can be met, and the defects of a single energy heating mode in the prior art in the aspects of energy efficiency, reliability, operation cost and the like are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of optimization control of heating, ventilation and air conditioning systems, and more particularly to a composite cold and heat source and control system. Background Art

[0002] Existing winter heating systems typically rely on several main heating methods: air-source heat pumps, ground-source heat pumps, and electric boilers. However, these heating methods each have certain limitations in practical applications, making it difficult to independently meet the demand for efficient and economical heating under complex and changing operating conditions.

[0003] Air source heat pumps are a widely used heating device with advantages such as low initial investment costs and flexible installation, making them particularly suitable for use in mild climates. However, their operating efficiency decreases significantly in low-temperature environments. This is mainly because when the outside air temperature drops, the air source heat pump's ability to extract heat from the environment weakens, the compressor workload increases, and the coefficient of performance (COP) decreases significantly, leading to higher operating costs. In extremely cold conditions, air source heat pumps may even be unable to meet heating needs, and other heat sources must be used for supplementary heating.

[0004] Because ground-source heat pumps utilize the relatively stable temperature resources underground, they can provide efficient and stable cooling and heating throughout the year. Their performance is less affected by external climatic conditions, the equipment has a long lifespan, and is highly energy-efficient. However, ground-source heat pumps also have certain limitations. During long-term operation, if the load distribution between winter and summer is unbalanced, it may lead to an imbalance in soil heat, which in turn affects their long-term operating performance. For example, continuous heat extraction in winter will cause the soil temperature to drop. If the heat is not re-injected during cooling in summer, the imbalance in soil temperature may be exacerbated, affecting the heat pump's operating efficiency in the next heating season. Therefore, how to achieve a dynamic balance of loads between winter and summer and maintain stable soil heat is a technical problem that needs to be solved in the operation of ground-source heat pumps.

[0005] As a traditional heating device, electric boilers perform very stably in extremely cold conditions. Because they directly convert electricity into heat, their thermal efficiency can reach nearly 100%, making them unaffected by fluctuations in external temperatures and able to quickly respond to heating needs. However, their operating costs are significantly affected by fluctuations in electricity prices, especially in areas and periods of high heating demand, where price fluctuations can lead to significant increases in heating costs. Furthermore, electric boilers are typically used only as auxiliary or emergency heat sources, making their sole use less economical and difficult to adapt to long-term, high-load heating needs.

[0006] In summary, the single heating mode in the existing heating system is difficult to achieve optimal operation under different environmental conditions and load levels; when the ambient temperature changes drastically or the heating load fluctuates greatly, the efficiency and reliability of the single heat source equipment are significantly reduced, resulting in energy waste and increased operating costs; this situation is particularly prominent in the cold northern regions, so there is an urgent need for a heating system that can organically combine and optimize the operation of multiple heat source equipment; the multi-energy combined heating system integrates equipment with different characteristics such as air source heat pumps, ground source heat pumps and electric boilers into one system, and dynamically adjusts the operating ratio of each equipment through intelligent control algorithms, which can achieve efficient, economical and reliable heating under variable working conditions; the development of this heating system based on multi-energy combination will help overcome the limitations of existing technologies and provide a more energy-saving and environmentally friendly solution for winter heating. Summary of the Invention

[0007] To overcome the above-mentioned shortcomings of the prior art, embodiments of the present invention provide a composite cooling and heating source and control system. By integrating an air-source heat pump, a ground-source heat pump, a solar thermal collector, an electric boiler, and their intelligent control system into a dynamically adjustable multi-energy combined operation system, this system achieves intelligent adaptation and efficient utilization of different seasons, load variations, and environmental parameters. In traditional heating systems, a single energy source cannot guarantee optimal operation under all operating conditions. The efficiency of a single heat source can fluctuate significantly when external temperature, load demand, or soil heat balance changes. The present invention utilizes ground-source heat pumps and air-source heat pumps as the primary cooling and heating sources, supplemented by solar thermal collectors and electric boilers as supplementary and emergency heat sources. Intelligent control is achieved through a host computer and a PLC control cabinet. The system is optimized for typical operating conditions in cold northern regions. In summer operation, ground-source heat pumps are preferred for cooling because the relatively stable underground temperature results in a higher COP, effectively reducing electricity consumption while meeting cooling needs. This addresses the shortcomings of the single-energy heating method in the prior art, as outlined in the background art, in terms of energy efficiency, reliability, and operating costs.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solutions: a composite cold and heat source and control system, comprising an energy device and an intelligent control system;

[0009] The energy device includes an air source heat pump device, a ground source heat pump device, a solar thermal collector device, and an electric boiler. The intelligent control system is connected and communicates with the air source heat pump device, the ground source heat pump device, the solar thermal collector device, and the electric boiler through a host computer and a PLC control cabinet to optimize energy utilization according to different seasons, load changes, and environmental parameters;

[0010] When the intelligent control system is running in summer, it uses a ground source heat pump device for cooling, taking advantage of the relative stability of underground temperature to improve the system's performance coefficient;

[0011] When the intelligent control system is operated in winter, the load threshold is set to Qe0. When the actual heating load Qe is less than Qe0, the air source heat pump device is started first. When Qe is greater than or equal to Qe0, the system automatically switches to the joint operation mode of the air source heat pump device and the ground source heat pump device.

[0012] The intelligent control system includes an emergency heat source startup function, which automatically starts the electric boiler as an emergency heat source when the water supply temperature fails to reach the set value within a predetermined time in the combined operation mode;

[0013] And based on historical data accumulation and regression analysis, energy utilization and adaptation are achieved;

[0014] The intelligent control system optimizes the operation strategy based on historical data accumulation and regression analysis method, predicts heating load changes and system operation performance, and adjusts the equipment startup sequence and parameter settings.

[0015] In a preferred embodiment, the intelligent control system includes a load monitoring module, a temperature monitoring module, an operation mode switching module and an emergency control module. The intelligent control system is used to monitor the heating load and water supply temperature in real time, and dynamically switch the operation mode and start the emergency heat source according to the monitoring results.

[0016] In a preferred embodiment, the air source heat pump device is connected to the ground source heat pump device via a circulating water system, and the circulating water system includes a buried pipe circulating water pump, whose energy consumption is calculated according to a polynomial model of flow rate to optimize the overall energy efficiency of the system;

[0017] The power of the underground pipe circulating water pump is dynamically adjusted according to the flow rate to achieve optimized management of variable flow energy consumption.

[0018] In a preferred embodiment, the solar thermal collector converts solar energy into thermal energy through a solar water heater, and transfers the heat of the heated circulating water to the soil through the buried pipes of the buried pipe circulating water pump, thereby heating the soil to ensure the negative nitrogen balance requirement of the buried pipes of the ground source heat pump device in winter and summer.

[0019] In a preferred embodiment, the intelligent control system monitors and adjusts the heating water temperature in real time. When the heating water temperature continues to be lower than the set value and exceeds the duration t1, another group of heat pump devices is automatically started to enter the combined heating mode; in the combined operation mode, if the heating water temperature still does not reach the set value within the specified time t2, the electric boiler is started to provide an emergency heat source.

[0020] In a preferred embodiment, the intelligent control system includes a host computer and a PLC control cabinet. The host computer is used for data processing and decision-making, and the PLC control cabinet is used to execute control instructions to achieve coordinated control of the air source heat pump device, ground source heat pump device, solar thermal collection device and electric boiler.

[0021] In a preferred embodiment, as the heat load Qe increases and exceeds the load threshold Qe0, the air source heat pump and the ground source heat pump enter a combined operation state. At this stage, the system will simultaneously determine whether to start the air source heat pump and the ground source heat pump, and select the optimal operation combination by calculating and comparing the COPs of the two. Before starting the equipment, the theoretical COPs of the ground source heat pump and the air source heat pump are first calculated, including the following calculation methods:

[0022]

[0023] Where: P GHSP,i is the energy consumption of ground source heat pump, unit is kW; t cw,s , t chw,s Q is the underground water inlet and heating water temperature, unit is ℃; e is the air conditioning heat load, unit kW; a 1,i -a 5,i is the chilled water pump model coefficient;

[0024] For the underground pipe circulating water pump, the power is fitted as a polynomial of the flow rate, and the variable flow energy consumption model of the underground pipe circulating water pump is obtained as follows:

[0025]

[0026] Where: G i is the flow rate of the i-th underground pipe circulating water pump, in m 3 / h;b 1,i -b 3,i is the chilled water pump model coefficient;

[0027] The theoretical ground source heat pump COP is calculated based on the load value and the theoretical ground source heat pump system energy consumption:

[0028]

[0029] The COP of an air source heat pump can be predicted based on the following formula:

[0030]

[0031] Where: t a , t chw,s is the air and heating water temperature, unit is ℃; Q e is the air conditioning heat load, unit kW; a 1,i -a5,i is the chilled water pump model coefficient.

[0032] Technical effects and advantages of the present invention:

[0033] 1. The intelligent heating system of the present invention further introduces an operating performance prediction mechanism based on historical data accumulation and quadratic complete regression analysis, which can accurately model and dynamically optimize the changing trend of heating load and system heating capacity; the system deploys multiple types of environmental and equipment status sensors to continuously collect operating parameters including outdoor air temperature, soil temperature, water supply temperature, heating load, operating status of each energy device and energy consumption data, and stores them in a structured manner in the database to form a system-level historical data set; on this basis, the control system generates operating performance regression coefficients a, b, and c through regression modeling to achieve intelligent prediction and adaptive optimization of heating strategies; by dynamically calculating the theoretical coefficient of performance (COP) of air source heat pumps and ground source heat pumps, the system prioritizes the use of equipment combinations with higher COPs, thereby effectively reducing the system energy consumption corresponding to unit heat output;

[0034] 2. During actual operation, the system monitors the heating water temperature in real time and sets temperature response thresholds t1 and t2 as control criteria. If the heating water temperature is continuously below the target setting and exceeds the time threshold t1, the system automatically determines that the existing heat source capacity is insufficient and quickly activates another set of heat pump units to form a joint operation mode to accelerate the recovery of the water supply temperature. If the water supply temperature still does not reach the set target within the threshold t2 after the joint operation, the system activates the electric boiler as an emergency heat source to ensure that indoor thermal comfort can be stably maintained under low temperature load peaks or extreme weather conditions. This multi-level heating guarantee mechanism significantly improves the system's responsiveness and reliability to sudden load changes.

[0035] 3. In addition, to address the potential soil heat imbalance caused by long-term operation of ground-source heat pumps, the present invention has established a ground temperature regulation mechanism based on a solar thermal collector. During transitional seasons when the ground-source heat pump is idle or when heat extraction is frequent, solar water heaters convert solar radiation into thermal energy, heating underground circulating water. This heat is then transferred to the underground heat exchange network, actively repairing and balancing the soil's thermal state. This process not only mitigates the trend of underground heat loss, but also improves the coordinated utilization efficiency of renewable energy sources such as solar energy, fundamentally enhancing the energy-saving stability of the system throughout the year.

[0036] 4. The present invention realizes the coordinated coupling and optimal allocation of multiple energy devices by constructing a multi-source fusion system of air source heat pumps, ground source heat pumps, solar thermal collectors and electric boilers, and introducing intelligent control strategies and dynamic operation prediction mechanisms. The system has strong seasonal adaptability, load regulation capabilities and abnormal operating condition response capabilities, and is particularly suitable for the complex and changeable heating demand scenarios in the cold northern regions. It not only effectively reduces operating energy consumption and energy costs, but also improves system stability, operating efficiency and sustainability, providing technical support with promotional value for green and low-carbon smart energy systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the system structure of the present invention.

[0038] Figure 2 Schematic diagram of the system control principle of the present invention. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0040] Refer to the instruction manual Figure 1-2 , a composite cold and heat source and control system according to an embodiment of the present invention includes an energy device and an intelligent control system;

[0041] The energy devices include an air source heat pump device, a ground source heat pump device, a solar thermal collector device, and an electric boiler. The intelligent control system is connected and communicates with the air source heat pump device, the ground source heat pump device, the solar thermal collector device, and the electric boiler through a host computer and a PLC control cabinet to achieve dynamic regulation and coordinated operation of each energy device to optimize energy utilization according to different seasons, load changes, and environmental parameters;

[0042] When the intelligent control system is running in summer, it gives priority to using ground source heat pump devices for cooling, taking advantage of the relative stability of underground temperature to improve the system's performance coefficient, thereby reducing power consumption;

[0043] When the intelligent control system is operated in winter, the load threshold is set to Qe0. When the actual heating load Qe is less than Qe0, the air source heat pump device is started first. When Qe is greater than or equal to Qe0, it automatically switches to the combined operation mode of the air source heat pump device and the ground source heat pump device, and selects the optimal operation combination mode by comparing the operating efficiency of the two.

[0044] The intelligent control system includes an emergency heat source startup function. When the water supply temperature fails to reach the set value within a predetermined time in the combined operation mode, the electric boiler is automatically started as an emergency heat source to ensure stable maintenance of indoor comfort under extreme working conditions.

[0045] And based on historical data accumulation and regression analysis, energy utilization and adaptation are achieved;

[0046] The intelligent control system optimizes the operation strategy based on historical data accumulation and regression analysis method, predicts the change of heating load and system operation performance, and adjusts the equipment startup sequence and parameter settings to reduce energy consumption and operating costs.

[0047] The intelligent control system includes a load monitoring module, a temperature monitoring module, an operation mode switching module and an emergency control module. The intelligent control system is used to monitor the heating load and water supply temperature in real time, and dynamically switch the operation mode and start the emergency heat source according to the monitoring results.

[0048] The air source heat pump device is connected to the ground source heat pump device through a circulating water system. The circulating water system includes a buried pipe circulating water pump, and its energy consumption is calculated according to a polynomial model of flow rate to optimize the overall energy efficiency of the system;

[0049] The power of the underground pipe circulating water pump is dynamically adjusted according to the flow rate to achieve optimized management of variable flow energy consumption.

[0050] The solar thermal collector converts solar energy into thermal energy through a solar water heater, and transfers the heat of the heated circulating water to the soil through the buried pipes of the buried pipe circulating water pump, thereby heating the soil and ensuring the negative nitrogen balance requirement of the buried pipes of the ground source heat pump device in winter and summer.

[0051] The intelligent control system monitors and adjusts the heating water temperature in real time. When the heating water temperature continues to be lower than the set value and exceeds the duration t1, another set of heat pump devices is automatically started to enter the combined heating mode; in the combined operation mode, if the heating water temperature still does not reach the set value within the specified time t2, the electric boiler is started to provide an emergency heat source.

[0052] The intelligent control system includes a host computer and a PLC control cabinet. The host computer is used for data processing and decision-making, and the PLC control cabinet is used to execute control instructions to achieve coordinated control of the air source heat pump device, ground source heat pump device, solar thermal collection device and electric boiler.

[0053] In response to the above scheme, the present invention proposes an air source heat pump-ground source heat pump-electric boiler composite cold and heat source and control system, which aims to dynamically adjust the system operation state by rationally utilizing the advantages of the three heating equipment, reduce energy consumption and improve the cooling and heating efficiency of the system; the system includes a cold and heat source system, a measurement system and a control system; the cold and heat source system consists of an air source heat pump, a ground source heat pump, a solar collector and an electric boiler, which are respectively suitable for different environmental conditions and load requirements; the measurement system includes a temperature sensor, a flow meter and an electric energy metering device, which is responsible for real-time collection of environmental and system operating parameters; the control system includes a host computer and a PLC control cabinet, which performs automatic regulation through intelligent algorithms; the system not only realizes efficient switching between air source heat pumps, ground source heat pumps and electric boilers, but also can flexibly select separate cooling and heating modes or joint operation modes through intelligent control strategies;

[0054] This invention takes the northern cold region as an example, the cold and heat source system is as follows Figure 1 As shown;

[0055] Summer conditions: Use a ground source heat pump with a higher COP for cooling, turn on pumps P2 and P3, open valves V3, V4, V5, and V6, and keep other pumps and valves closed;

[0056] In winter, when the load Qe is less than Qe0: the system starts the air source heat pump first, turns on pump P1, opens valves V1 and V2, and keeps other pumps and valves closed; when the load Qe is greater than or equal to the threshold Qe0, the system calculates the theoretical coefficient of performance (COP) of the air source heat pump and the ground source heat pump, and selects the device with better performance to start by comparison; the control system regulates the start and stop of pumps P1, V1, V2 or P2, V3, V4, P3, V5, V6; this process ensures that the heating equipment operates at the highest efficiency under different load conditions; if the water supply temperature does not reach the target value and the duration exceeds the set time threshold t1, the system will start another set of heating equipment and enter the combined heating mode, turning on P1, V1, V2 and P2, V3, V4, P3, V5, V6 at the same time, and adjusting the power of P1 and P2 through the control system; in the combined operation mode, if the water supply temperature still does not reach the target value and the duration below the target value exceeds the threshold t2, the system will start the electric boiler as an emergency heat source to quickly increase the water supply temperature to ensure that the heating demand can be met even under extreme working conditions, that is, continue to turn on P5, V9, V10 in the combined heating mode;

[0057] Transition season: Turn on the solar thermal collector and P4, V7, and V8, and keep other pumps and valves closed to balance the cooling and heating loads in winter and summer;

[0058] During winter operation, the system flexibly switches operating modes based on actual load conditions to adapt to varying heating demands and environmental changes. Specifically, when the outside climate is relatively mild and the load is light, the system sets a load threshold, Qe0, which is determined by the load capacity of the air-source heat pump and its efficient operating range. When the threshold falls below Qe0, the system prioritizes starting the air-cooled heat pump. Air-cooled heat pumps are more convenient to start under low load conditions, and their equipment cost and operating economy are better.

[0059] As the heat load Qe increases and exceeds the load threshold Qe0, the system automatically enters the joint operation state of the air source heat pump and the ground source heat pump. In this stage, the system will simultaneously determine whether to start the air source heat pump and the ground source heat pump, and select the optimal operation combination by calculating and comparing the COP of the two. Before starting the equipment, the theoretical COP of the ground source heat pump and the air source heat pump are first calculated, mainly through the following calculation method:

[0060]

[0061] Where: P GHSP,i is the energy consumption of ground source heat pump, unit is kW; t cw,s , t chw,s is the underground water inlet and heating water supply temperature, unit is ℃; Q e is the air conditioning heat load, unit kW; a 1,i -a 5,i is the chilled water pump model coefficient;

[0062] For the underground pipe circulating water pump, the power is fitted as a polynomial of the flow rate, and the variable flow energy consumption model of the underground pipe circulating water pump is obtained as follows:

[0063]

[0064] Where: G i is the flow rate of the i-th underground pipe circulating water pump, in m 3 / h;b 1,i -b 3,i is the chilled water pump model coefficient;

[0065] The theoretical ground source heat pump COP is calculated based on the load value and the theoretical ground source heat pump system energy consumption:

[0066]

[0067] The COP of an air source heat pump can be predicted based on the following formula:

[0068]

[0069] Where: t a , t chw,s is the air and heating water temperature, ℃; Qe is the air conditioning heat load, kW; a 1,i -a 5,i is the chilled water pump model coefficient;

[0070] The intelligent heating system of the present invention further utilizes historical data accumulation and quadratic complete regression analysis to accurately predict and optimize changes in heating load and the system's heating performance. The system, equipped with a variety of sensors and monitoring devices, continuously collects and records various data generated during operation, including outdoor air temperature, soil temperature, water supply temperature, heating load, equipment operating status, and energy consumption data of various energy devices. This data is systematically stored in a database, forming a detailed historical data set. Using quadratic complete regression analysis, the system models the collected historical data and fits regression coefficients a, b, and c that reflect the system's operating characteristics.

[0071] By comparing theoretical COPs, prioritizing the use of equipment with higher COPs can effectively reduce system energy consumption. In actual operation, the system monitors the heating water temperature in real time. If the heating water temperature remains below the set value for a period exceeding t1, indicating insufficient heating capacity, the system quickly activates another set of heat pumps to achieve combined heating mode, thereby accelerating the recovery of the water temperature. In combined operation mode, if the heating water temperature still does not reach the set value within the specified time t2, the system activates the electric boiler to provide an emergency heat source, ensuring stable indoor comfort even in adverse operating conditions.

[0072] During transitional seasons when the ground-source heat pump is not in use, the system uses solar thermal collectors to reheat groundwater, preventing soil temperature imbalances caused by long-term operation of the ground-source heat pump and maintaining soil temperature stability. The solar thermal collectors convert solar energy into thermal energy through solar water heaters, which in turn heats the circulating water. The heat from the heated circulating water is transferred to the soil through the buried pipe system, heating the soil side. This process not only alleviates the continuous cooling pressure of the ground-source heat pump on the groundwater, but also fully utilizes solar energy, a renewable energy source, further improving the overall energy efficiency of the system.

[0073] Through this dynamic optimization and regulation, the present invention not only realizes the flexible and efficient combination of multiple energy equipment, but also ensures efficient heating and cooling under different environmental parameters and load levels; in short, the present invention organically integrates ground source heat pumps, air source heat pumps, solar thermal collectors, electric boilers and their intelligent control systems, and uses advanced data measurement and analysis methods and real-time intelligent control strategies to achieve efficient coordination and dynamic optimization of multiple energy sources; thereby meeting the diversified heating needs of cold northern regions; under the premise of meeting indoor comfort requirements, the present invention significantly reduces operating costs and energy consumption, improves the stability, scalability and energy-saving and environmental protection properties of the system, and provides strong support for the development and application of future smart energy systems.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite cold and heat source and control system, including an energy device and an intelligent control system, characterized by: The energy device includes an air source heat pump device, a ground source heat pump device, a solar thermal collector device, and an electric boiler. The intelligent control system is connected and communicates with the air source heat pump device, the ground source heat pump device, the solar thermal collector device, and the electric boiler through a host computer and a PLC control cabinet to optimize energy utilization according to different seasons, load changes, and environmental parameters; When the intelligent control system is running in summer, it uses a ground source heat pump device for cooling, taking advantage of the relative stability of underground temperature to improve the system's performance coefficient; When the intelligent control system is operated in winter, the load threshold is set to Qe0. When the actual heating load Qe is less than Qe0, the air source heat pump device is started first. When Qe is greater than or equal to Qe0, the system automatically switches to the joint operation mode of the air source heat pump device and the ground source heat pump device. The intelligent control system includes an emergency heat source startup function, which automatically starts the electric boiler as an emergency heat source when the water supply temperature fails to reach the set value within a predetermined time in the combined operation mode; And based on historical data accumulation and regression analysis, energy utilization and adaptation are achieved; The intelligent control system optimizes the operation strategy based on historical data accumulation and regression analysis method, predicts heating load changes and system operation performance, and adjusts the equipment startup sequence and parameter settings.

2. A composite cold and heat source and control system according to claim 1, characterized in that: The intelligent control system includes a load monitoring module, a temperature monitoring module, an operation mode switching module and an emergency control module. The intelligent control system is used to monitor the heating load and water supply temperature in real time, and dynamically switch the operation mode and start the emergency heat source according to the monitoring results.

3. A composite cold and heat source and control system according to claim 2, characterized in that: The air source heat pump device is connected to the ground source heat pump device through a circulating water system. The circulating water system includes a buried pipe circulating water pump, and its energy consumption is calculated according to a polynomial model of flow rate to optimize the overall energy efficiency of the system; The power of the underground pipe circulating water pump is dynamically adjusted according to the flow rate to achieve optimized management of variable flow energy consumption.

4. A composite cold and heat source and control system according to claim 3, characterized in that: The solar thermal collector converts solar energy into thermal energy through a solar water heater, and transfers the heat of the heated circulating water to the soil through the buried pipes of the buried pipe circulating water pump, thereby heating the soil and ensuring the negative nitrogen balance requirement of the buried pipes of the ground source heat pump device in winter and summer.

5. A composite cold and heat source and control system according to claim 4, characterized in that: The intelligent control system monitors and adjusts the heating water temperature in real time. When the heating water temperature continues to be lower than the set value and exceeds the duration t1, another set of heat pump devices is automatically started to enter the combined heating mode; in the combined operation mode, if the heating water temperature still does not reach the set value within the specified time t2, the electric boiler is started to provide an emergency heat source.

6. A composite cold and heat source and control system according to claim 5, characterized in that: The intelligent control system includes a host computer and a PLC control cabinet. The host computer is used for data processing and decision-making, and the PLC control cabinet is used to execute control instructions to achieve coordinated control of the air source heat pump device, ground source heat pump device, solar thermal collection device and electric boiler.

7. The composite cold and heat source and control system according to claim 6, characterized in that: As the heat load Qe increases and exceeds the load threshold Qe0, the system enters the joint operation state of the air source heat pump and the ground source heat pump. In this stage, the system will simultaneously determine whether to start the air source heat pump and the ground source heat pump, and select the optimal operation combination by calculating and comparing the COP of the two. Before starting the equipment, the theoretical COP of the ground source heat pump and the air source heat pump are first calculated, including the following calculation methods: P GHSP,i =a 0,i +a 1,i (t chw,s -t cw,s )+ a 2,i (t chw,s -t cw,s ) 2 + a 3,i (t chw,s -t cw,s )Q e + a 4,i Q e +a 5,i Q e 2 Where: P GHSP,i is the energy consumption of ground source heat pump, unit is kW; t cw,s , t chw,s Q is the underground water inlet and heating water temperature, unit is ℃; e is the air conditioning heat load, unit kW; a 1,i -a 5,i is the chilled water pump model coefficient; For the underground pipe circulating water pump, the power is fitted as a polynomial of the flow rate, and the variable flow energy consumption model of the underground pipe circulating water pump is obtained as follows: P pump,i =b 0,i +b 1,i G i +b 2,i G i 2 +b 3,i G i 3 Where: G i is the flow rate of the i-th underground pipe circulating water pump, in m 3 / h;b 1,i -b 3,i is the chilled water pump model coefficient; The theoretical ground source heat pump COP value is calculated based on the load value and the theoretical ground source heat pump system energy consumption: The COP of an air source heat pump can be predicted based on the following formula: COP ASHP =c 0,i +c 1,i (t chw,s -t a )+ c 2,i (t chw,s -t a ) 2 + c 3,i (t chw,s -t a )Q e + c 4,i Q e +c 5,i Q e 2 Where: t a , t chw,s is the air and heating water temperature, unit is ℃; Q e is the air conditioning heat load, unit kW; a 1,i -a 5,i is the chilled water pump model coefficient.

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