An intelligent heating system based on an air source heat pump and a control method thereof
Patent Information
- Application Number
- CN202610572401.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-28
- Publication Date
- 2026-06-23
Smart Images
Figure CN122258433A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of energy-saving air conditioning and heat pump control technology, specifically to a smart heating system and control method based on an air source heat pump. Background Technology
[0002] Current dual-mode solar heat pump air conditioning units utilize low-grade heat sources such as solar energy as their primary energy input, offering significant advantages in energy conservation and consumption reduction, aligning with current building heating development trends. However, these heat pump systems, characterized by low-grade heat sources, still face technical bottlenecks related to control lag and safety protection during mode switching and cross-medium heat exchange.
[0003] During the transition period of heating mode switching, existing control systems typically employ conventional feedback control algorithms based on indoor temperature deviations. Due to the thermal inertia of the building envelope, simple temperature feedback suffers from physical phase lag. By the time the system senses a substantial temperature drop, the heat deficit at the source has already amplified, forcing the system to drive the compressor to start excessively frequently or even frequently start and stop. This hysteretic response not only fails to smoothly extract low-grade heat but also generates a large amount of ineffective operating power consumption, severely limiting the unit's energy-saving potential.
[0004] When deeply extracting low-grade waste heat under extremely cold conditions, the unit needs to rely on heat exchangers for cross-medium heat exchange. Existing water-side anti-freeze mechanisms mainly rely on water temperature sensors for threshold judgment, which is limited by the thermal inertia of the fluid and the sensor, resulting in a slow temperature monitoring response. During the rapid heat extraction process of the heat pump, the anti-freeze protection action often lags behind the transient drop in local temperature inside the heat exchanger, easily causing the equipment to freeze and crack. This not only threatens the physical safety of the unit but also limits the system's continuous utilization of low-grade heat sources and overall energy-saving effect. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a smart heating system and control method based on an air source heat pump. This solves the problems of existing dual-condition solar heat pump air conditioning units, which suffer from ineffective high-frequency start-stop of the compressor due to control lag during the condition switching period, resulting in energy waste, and slow antifreeze response when extracting low-grade heat sources, posing a risk of heat exchanger freezing and cracking.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] The first aspect of this invention provides a smart heating system based on an air-source heat pump. This system physically integrates a solar collector subsystem and an air-source heat pump unit, utilizing a flow path switching device to regulate the flow direction of the fluid medium between the heating terminal loop and the auxiliary heat exchange side of the air-source heat pump. Specifically, the auxiliary heat exchange side is a plate heat exchanger connected to the suction side of the variable frequency compressor. The system acquires the inlet and outlet water temperatures of the solar collector at the source end and the flow rate on the collector side, as well as the indoor ambient temperature at the load end, through a sensor network, and submits this information to the main controller for dynamic feedforward calculation and actuator scheduling.
[0008] In the feedforward determination mechanism for system operating condition switching, the main controller does not rely on a single temperature deviation, but rather calculates the instantaneous heating power based on the thermodynamic law of conservation of energy, using the temperature difference between the inlet and outlet water, the flow rate on the heat collector side, and the physical properties of the medium, and extracts the time first derivative of this power to obtain the heat flow attenuation rate at the source end.
[0009] By monitoring whether the decay rate is negative and its absolute value exceeds the calibrated threshold, the system can detect the trend of heat source energy depletion before a substantial drop in indoor temperature occurs. To prevent malfunctions caused by transient hydraulic disturbances in the pipe network, the triggering logic is supplemented with a continuous sampling period maintenance condition. After confirming the decay, the main controller drives the flow path switching device to introduce the heat collector side medium with residual heat into the plate heat exchanger as a low-grade auxiliary heat source for the heat pump.
[0010] In the energy compensation mechanism during the dual-condition transition period, this system abandons conventional proportional-integral-derivative control and constructs a multivariable collaborative frequency mapping model. The main controller calculates the discrete integral of the dynamic difference between the target temperature and the indoor ambient temperature within a sliding time window to obtain the load-side heat capacity lag integral. This is used to quantify the heat storage state of the building envelope.
[0011] The initial start-up frequency command is generated by superimposing the base maintenance frequency, the attenuation compensation based on the heat flux decay rate, and the heat capacity suppression based on the heat capacity hysteresis integral. This mechanism utilizes the building's own heat storage capacity to numerically offset the compressor frequency increase trend caused by a sudden drop in external heat, overcoming the ineffective high-frequency start-up and energy waste during the transition period.
[0012] In the cross-medium heat transfer anti-freeze protection mechanism, considering the response lag caused by the thermal inertia of the water temperature sensor, the system introduces the refrigerant side suction pressure as a feedforward monitoring parameter. Based on the thermodynamic saturated properties of the refrigerant, the drop in suction pressure directly reflects the decrease in evaporation temperature.
[0013] The main controller synchronously calculates the first derivative of the suction pressure with respect to time to obtain the pressure decay rate. When the pressure decay rate exceeds the safe decay threshold and the water temperature approaches the warning threshold, the main controller directly sends an acceleration command to the variable frequency circulating pump on the solar side. By increasing the fluid flow rate, the heat carried by the input plate heat exchanger is forcibly increased, thereby smoothing out the rapidly decreasing temperature curve on the evaporator side.
[0014] In the extreme operating condition safety exit mechanism, if the solar heat is depleted and the circulation pump speed is increased but still cannot prevent the outlet water temperature from falling below the extreme freezing threshold and reaching the safety confirmation time, the main controller will execute a hardware reset. This disconnects the physical heat exchange link between the water system and the plate heat exchanger and reconfigures the drive logic of the four-way reversing valve inside the heat pump unit, causing the variable frequency compressor to switch back to the normal heating state of extracting heat from the outdoor air, thus ensuring the physical safety of the core hardware.
[0015] In addition, to ensure the convergence of the above derivative and integral operations, the main controller uses a built-in digital filtering algorithm to perform first-order low-pass smoothing on the raw sensor data before executing the core calculation, thereby blocking the interference of high-frequency electromagnetic noise and fluid pulsation on the microprocessor's differential operations.
[0016] A second aspect of this invention provides a control method for a smart heating system based on an air-source heat pump. This method sequentially performs data acquisition and timing alignment, calculates the source-side heat flux decay rate reflecting changes in heating potential based on the source-side state parameters of the solar collector subsystem, and calculates the load-side heat capacity lag integral reflecting the building's thermal inertia based on the load-side state parameters and the target temperature. The system triggers multi-cycle soft-switching decisions by monitoring the source-side heat flux decay rate, smoothly reconstructing a single heating mode into a low-grade heat source-assisted extraction mode. During mode reconstruction, the system utilizes the collaborative constraint relationship between the source-side heat flux decay rate and the load-side heat capacity lag integral to calculate instructions, guiding the variable frequency compressor to perform feedforward frequency compensation, thereby achieving a dynamic balance between energy supply and demand.
[0017] This invention provides a smart heating system and control method based on an air source heat pump. It has the following beneficial effects:
[0018] 1. This invention constructs a multivariable collaborative frequency mapping control model by calculating the heat flux decay rate at the source end of the solar thermal collector subsystem and the lag integral of the heat capacity on the building load side. This model enables the early detection of energy depletion trends using the first derivative of heat flux decay and the calculation of heat capacity suppression using the building's heat storage margin. This numerically cancels the compressor's frequency increase command, overcoming the physical phase lag defect of conventional temperature feedback control. It effectively suppresses the ineffective high-frequency start-up of the variable frequency compressor during heating mode switching and avoids energy waste caused by excessive response during the transition period.
[0019] 2. This invention sets up a flow path switching device between the heating terminal circuit and the auxiliary heat exchange side of the air source heat pump. When the main controller determines that the heat flow attenuation rate at the source end continuously exceeds the limit and confirms that the solar collector has lost its independent heating capacity, the system will activate and introduce the heat collection side medium with low-grade waste heat into the plate heat exchanger. This replaces the outdoor cold air under extremely cold conditions as the bottom heat source of the thermal cycle, effectively increases the evaporation temperature of the system and reduces the actual operating pressure ratio of the compressor, ensuring the continuity of heating when a single heat source is depleted.
[0020] 3. To address the risk of localized icing and cracking that can easily occur in dual-condition coupled systems under extreme conditions, this invention introduces the first derivative of the refrigerant suction pressure with respect to time as a feedforward monitoring parameter. Combined with the multi-dimensional determination of the collector outlet water temperature, when the main controller detects a sharp drop in suction pressure, it directly increases the speed of the variable frequency collector-side circulation pump to forcibly increase the heat carried by the water side. This eliminates the inherent thermal inertia measurement delay of a single water temperature sensor and can smooth out the temperature drop on the evaporator side before the fluid inside the heat exchanger falls below the freezing point, preventing freezing damage to the physical equipment. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the system structure topology according to an embodiment of the present invention;
[0022] Figure 2 This is a schematic diagram of the overall process of an embodiment of the present invention;
[0023] Figure 3 The source-end heat flux attenuation and operating condition switching response curves are embodiments of the present invention. Figure 1 ;
[0024] Figure 4 The source-end heat flux attenuation and operating condition switching response curves are embodiments of the present invention. Figure 2 ;
[0025] Figure 5 This is a comparison curve of indoor ambient temperature fluctuations in an embodiment of the present invention;
[0026] Figure 6 This is a comparison curve of the operating frequency response of the variable frequency compressor according to an embodiment of the present invention;
[0027] Figure 7 This is a response curve for the antifreeze protection limit test according to an embodiment of the present invention. Detailed Implementation
[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] See attached document Figure 1 An embodiment of the present invention provides a smart heating system based on an air source heat pump. This system constitutes a dual-condition solar heat pump air conditioning unit, which aims to reduce the overall energy consumption of the system through dynamic allocation of heat from the source side and feedforward mapping of the equipment operating frequency.
[0030] The system includes a solar thermal collector subsystem. In this embodiment, the solar thermal collector subsystem specifically includes a solar collector, which is configured as a flat-plate solar collector or a evacuated tube solar collector. The outlet of the solar collector is connected to a collector-side circulation pump via a pipeline. To achieve dynamic adjustment of the circulating water flow rate to match the real-time fluctuations in solar irradiance, the collector-side circulation pump is specifically a variable frequency collector-side circulation pump.
[0031] In order to achieve physical isolation and flow path reconfiguration of different heating modes, the system is equipped with a flow path switching device to control the flow direction of the fluid medium.
[0032] As a preferred approach, the flow path switching device is implemented in hardware as an electric three-way regulating valve. The output of the variable frequency solar collector circulating pump is connected to the input of the electric three-way regulating valve via a pipeline. The first output of the electric three-way regulating valve is connected to the heating terminal via a direct supply pipeline, forming a direct solar heating loop. The second output of the electric three-way regulating valve is connected to the air source heat pump unit via a series pipeline, forming a series auxiliary heating loop. This series loop aims to overcome the physical bottleneck of the lower water temperature limit in conventional direct heating modes.
[0033] An air-source heat pump unit internally includes a variable frequency compressor, a finned heat exchanger on the outdoor air side, and an auxiliary heat exchange side. The auxiliary heat exchange side is specifically structured as a plate heat exchanger or a shell-and-tube heat exchanger. The medium inlet of the plate heat exchanger is connected to the second output of an electrically operated three-way regulating valve to receive warm water from the solar collector. The refrigerant end of the plate heat exchanger is connected to the suction side of the variable frequency compressor, enabling cross-medium heat exchange between water and refrigerant.
[0034] The technical purpose of introducing this cross-medium heat exchange mechanism is to use the heat collection side outlet water with a certain residual temperature to replace the outdoor air under extremely cold conditions as the low-temperature heat source for thermal circulation, thereby effectively increasing the evaporation temperature, reducing the actual operating pressure ratio of the variable frequency compressor, and thus achieving the technical effect of reducing power consumption.
[0035] For the connection relationship and working principle of conventional four-way valve switching and refrigerant circulation components such as condensers and throttle valves inside air source heat pump units, those skilled in the art can refer to existing mature heat pump unit design specifications for implementation.
[0036] At the data sensing level, the system is equipped with a sensor network. This sensor network specifically includes inlet and outlet water temperature sensors, a collector-side flow sensor, an indoor ambient temperature sensor, and a suction pressure sensor. The inlet and outlet water temperature sensors are installed on the inlet and outlet main pipes of the solar collector, respectively, and specifically employ PT100 platinum resistance temperature sensors.
[0037] The collector-side flow sensor is installed on the outlet pipe of the solar collector, specifically using an electromagnetic flow meter or an ultrasonic flow meter. The indoor ambient temperature sensor is placed in the building environment where the heating terminal is located. The suction pressure sensor is installed on the suction pipe of the variable frequency compressor, specifically using a piezoresistive pressure sensor.
[0038] The system includes a main controller. The underlying physical hardware of the main controller uses a programmable logic controller, microcontroller, or digital signal processor. The variable frequency heat collector side circulating pump, electric three-way regulating valve, variable frequency compressor, and sensor network are all electrically connected to the main controller via hardwired connections or industrial communication buses to achieve bidirectional interaction between control signals and feedback parameters.
[0039] Based on the aforementioned hardware topology and data acquisition network, this system addresses the excessive energy consumption of a single cold / heat source system under extreme operating conditions by executing a closed-loop logic. During the overall operation of the system, the main controller sequentially executes the following macroscopic workflow:
[0040] S101, the source-side state parameters specifically include the inlet and outlet water temperatures of the solar collector and the flow rate on the collector side, while the load-side state parameters specifically include the indoor ambient temperature. Considering the differences in electrical response delays of different physical quantity sensors, after receiving the data, the main controller performs timestamp alignment processing on the multi-source data streams using a built-in high-frequency hard clock to eliminate distorted data caused by communication packet loss, thereby ensuring the boundary convergence of subsequent differentiation and integration operations.
[0041] S102, after completing the data timing alignment, the main controller calculates the source-side heat flow attenuation rate based on the inlet and outlet water temperatures and the collector-side flow rate, and calculates the load-side heat capacity hysteresis integral based on the indoor ambient temperature and the set target temperature.
[0042] S103 To avoid malfunctions of actuators caused by transient hydraulic fluctuations in the fluid pipeline, the judgment process does not rely on the extreme value crossing of a single point, but instead performs multi-dimensional verification by combining the continuous period of the parameter change slope.
[0043] When the conditions are met, the main controller outputs a control signal to the electric three-way regulating valve. The electric three-way regulating valve responds to the signal and performs a mechanical action, switching the flow direction of the fluid medium from the first output end to the second output end, so that the warm water flowing out of the solar collector enters the plate heat exchanger to provide a low-grade heat source, and the system enters a dual-condition coupled operation mode.
[0044] S104. During the flow path reconstruction, in order to make up for the heat vacuum gap during the system transition period, the main controller generates an initial start-up frequency command based on the joint calculation results of the source heat flow attenuation rate and the load side heat capacity hysteresis integral and sends it to the variable frequency driver of the variable frequency compressor. The variable frequency compressor starts according to the received frequency command and performs heat compensation.
[0045] S105 During the operation of the variable frequency compressor, the main controller synchronously monitors the time derivative of the suction pressure, and when it determines that the suction pressure decay rate exceeds the safe decay threshold, it sends a speed increase command to the variable frequency heat collector side circulation pump to perform water-side anti-freeze protection adjustment.
[0046] Based on the hardware topology and macroscopic process constructed in the aforementioned embodiments, in order to ensure the numerical stability of the core feedforward parameter calculation, this embodiment elaborates on the parameter preprocessing and underlying data anti-interference mechanism inside the main controller.
[0047] Sensor networks in industrial environments are susceptible to high-frequency harmonic coupling from variable frequency drives (VFDs) and physical interference from fluid vortex pulsations within pipelines. If such high-frequency interference noise is not eliminated before entering the subsequent discrete differentiation calculation stage, the amplification effect of the numerical difference will cause the differential term to diverge, resulting in the VFD compressor and electric three-way control valve receiving invalid oscillation control commands.
[0048] Based on the above causal relationship, the main controller is set to perform anti-aliasing filtering on the acquired data stream before performing the calculation of the source-side heat flux decay rate and the load-side heat capacity hysteresis integral.
[0049] To address the above requirements, the main controller internally performs the following parameter preprocessing steps:
[0050] S201. For thermal parameters such as temperature and flow rate, considering that heating systems usually have a large thermal inertia, the sampling period setting needs to match the actual thermodynamic response delay of the heating system.
[0051] In this embodiment, the main controller continuously acquires the time-series raw data of inlet and outlet water temperatures, collector flow rate, and indoor ambient temperature from the sensor network based on a fixed sampling period. During the data reading process, to prevent outliers caused by sudden sensor disconnections or short circuits from contaminating subsequent iteration sequences, the main controller pre-introduces threshold clamping logic.
[0052] Specifically, when the acquired raw data exceeds the physical tolerance limit of the device, the main controller will determine that the data is invalid and forcibly reset it to the valid value of the previous sampling period, thereby blocking the downstream transmission of erroneous data.
[0053] S202, the main controller invokes its internally configured digital filtering algorithm to perform first-order low-pass smoothing on the raw time series data. From the perspective of general signal processing principles, first-order low-pass smoothing can effectively suppress AC components above the set cutoff frequency, while fully preserving the DC and low-frequency slowly varying components that characterize the true physical state of the system. This is done to accommodate the limited memory overhead and real-time computational requirements of the microprocessor;
[0054] As a preferred approach, this smoothing process is specifically implemented as a discretized first-order inertial iterative stage. The main controller uses the set filter weights to perform algebraic reconstruction of the raw data at the current time step and the effective data at the previous time step, calculating the current filter parameters. Its built-in discrete filtering mathematical model is expressed as:
[0055] ;
[0056] In this relation The representation system in the current number Raw time-series data obtained from each sampling period; The representation after first-order low-pass smoothing is the current number. Filtering parameters for each sampling period; Characterizing the previous one The filtering parameters retained for each sampling period; Characterized by dimensionless filter coefficients.
[0057] As a fundamental boundary condition to ensure the stability of the algorithm, the filter coefficients The value range is strictly limited to the open interval (0,1). The specific value of this filter coefficient is derived based on the actual physical sampling characteristics, and its determination logic is expressed as follows:
[0058] ;
[0059] In this mapping relationship, The data sampling period set in characterization step S201 is in seconds; It represents the filtering time constant set for a specific physical quantity, and its unit is also s.
[0060] In the underlying algorithm architecture, since the sampling period and filtering time constant of real-world data are physically constrained to be real numbers greater than zero by the underlying program, the denominator is always greater than zero. In this algebraic operation process, the system naturally avoids the singular division error caused by the denominator approaching zero.
[0061] The purpose of introducing the aforementioned time constant is to establish a balance adjustment mechanism between data response agility and noise suppression depth. The filter coefficients essentially constitute the weights in the trade-off between dynamic tracking and static noise filtering in the algorithm.
[0062] Setting a large filter time constant for a specific sensor results in a smaller filter coefficient and enhanced system suppression of high-frequency pulsation noise. However, this also introduces a significant time phase lag to the actual changes in physical parameters. For calibrating the optimal filter time constant under various operating conditions, those skilled in the art can perform adaptive matching based on the electromagnetic compatibility environment test results of the on-site frequency converter and the impedance characteristics of the fluid pipeline network.
[0063] By executing the aforementioned low-pass smoothing logic, the main controller effectively filters out high-frequency interference noise and writes the output filtered parameters into the controller's secure storage area. Subsequently, the main controller extracts these filtered parameters and directly substitutes them into subsequent derivative and integral calculation stages, thereby providing a clean and continuously differentiable basic data source for dual-mode switching and compressor frequency conversion mapping.
[0064] After acquiring the clean and effective data stream through first-order low-pass smoothing, this embodiment further elaborates on the physical modeling process of the main controller performing a quantitative evaluation of the source-side heating capacity and load-side thermal inertia. This is done to establish a specific numerical mapping relationship between the system feedforward response and energy compensation;
[0065] As a preferred approach, the main controller is equipped with an active load dual-end dynamic feedforward parameter calculation module.
[0066] Based on the preprocessed sensor data, the main controller sequentially performs the following calculation steps:
[0067] S301. In the process of assessing the energy at the source, simply obtaining the outlet water temperature of the solar collector cannot truly reflect the actual heating potential of the system, because fluctuations in the flow velocity in the pipes can lead to huge differences in the amount of heat transferred at the same water temperature.
[0068] Based on the aforementioned physical causal relationship, the main controller calculates the instantaneous heating power for the current sampling period based on the inlet and outlet water temperatures of the solar collector and the flow rate on the collector side. From the fundamental law of conservation of energy in thermodynamics, the instantaneous heating power reflects the actual rate at which the collector subsystem injects effective heat into the fluid medium. In this embodiment, the energy calculation algebraic model internal to the main controller is expressed as:
[0069] ;
[0070] In this formula, The representation system in the current number The instantaneous heating power of a sampling period is expressed in W (watts). The isobaric specific heat capacity characterizing the fluid medium inside the system; Characterizes the density of the fluid medium; Characterizes the heat collector-side flow rate after digital filtering; and The outlet and inlet water temperatures of the solar collector, respectively, are represented by the digitally filtered water.
[0071] For the physical property parameters in the formula and Since the actual values of the fluid working medium will drift non-linearly with the operating temperature, those skilled in the art can pre-program a quick lookup table of the corresponding fluid properties into the non-volatile memory of the main controller. The main controller obtains the corrected values of the fluid properties based on the real-time temperature through table lookup or interpolation.
[0072] S302, to capture the dynamic decline trend of the source-end heating capacity, the main controller performs a first-order time-dimension derivative operation on the continuously calculated instantaneous heating power to extract the source-end heat flux attenuation rate. Considering the physical limitations of the discrete sampling system, the main controller uses a first-order backward differential approximation method for numerical differentiation, which is mathematically expressed as:
[0073] ;
[0074] In this difference expression, Characterizes the source-end heat flux decay rate calculated at the current moment; It represents the instantaneous heating power calculated and stored in the buffer during the previous sampling period.
[0075] In a real-world engineering environment, if the timestamp difference between two consecutive frames of data is small or even zero due to congestion on the communication bus of a multi-source heterogeneous network, directly performing the division will cause a processor overflow fault where the denominator approaches zero.
[0076] To verify the completeness of the algorithm, the main controller has overflow protection logic set up before executing the division instruction:
[0077] When calculated When the time tolerance is less than the system's set minimum tolerance threshold, the main controller skips the current differential operation and forces... It is equal to the historical state value of the previous effective period.
[0078] From an engineering physics perspective, when external solar irradiance decreases due to cloud cover or the alternation of day and night... This will result in a negative value. Extracting this first derivative value allows the control system to detect early signs of energy depletion at the heat source before a substantial drop in indoor ambient temperature, thus laying the foundation for a feedforward prediction mechanism.
[0079] S303, during the synchronization of source-side calculations, the main controller performs heat capacity lag integral calculations for the building's environmental load side. Due to the inherent material properties and mass of the building envelope, there is significant thermal inertia, and fluctuations in indoor temperature usually lag behind the heat input or interruption on the heating side.
[0080] To quantify the energy supply and demand shift caused by the heat storage effect, the main controller calculates the dynamic difference between the set target temperature and the indoor ambient temperature, and performs discrete-time integral calculations within a preset time window. In this embodiment, the integral expression formula is:
[0081] ;
[0082] In this discrete integral model Characterizes the load-side heat capacity hysteresis integral of the system at the current moment; Characterizes the target temperature set by the user; Characterizing the first Effective filtered value of indoor ambient temperature for each sampling period; The length of the set sliding time window is represented by the number of sampling periods. The building heat capacity correction coefficient is introduced. This coefficient is a dimensionless empirical constant, and its value range is usually set between 0.5 and 1.5. The specific value is dynamically matched according to the heat storage specific capacity of the building wall material.
[0083] Of the parameters mentioned above, The value depends on the thickness of the building envelope and the type of insulation material. Its calibration is typically achieved by establishing a step thermal response test curve for a specific building, such as a conventional brick-concrete structure. The corresponding time span is generally defined as within the range of 1 to 3 hours. The technical purpose of introducing this integral term is to account for situations where the indoor ambient temperature does not meet the standard within a short period of time. When the cumulative value is small, it indicates that the building walls are releasing heat stored in the lower layers into the interior. If the controller directly starts the compressor to increase its frequency based on a large transient temperature difference, it will cause ineffective high-frequency oscillation of the equipment and waste electrical energy. Conversely, if the integral value exceeds a certain benchmark, it indicates that there is a real, deep heat deficit in the environment.
[0084] Furthermore, to avoid integral saturation caused by prolonged temperature differences, which could lead to compressor frequency command malfunction, the main controller incorporates a feature in its closed-loop operation to prevent this. The anti-saturation clamping module. When the calculated integral value exceeds the calibrated safe physical limit, its output is forcibly constrained to equal that limit. The extraction of this integral parameter and the establishment of the clamping protection mechanism provide stable boundary constraints for smoothing the unit's operating amplitude in subsequent calculations.
[0085] Based on the extraction of dynamic feedforward parameters at both ends of the source and load as described above, in order to achieve physical reconstruction of the heating mode and seamless and smooth energy connection, this embodiment provides a detailed description of the dual-condition feedforward triggering and compressor multivariable mapping control mechanism inside the main controller.
[0086] After obtaining the aforementioned solution parameters, the main controller executes the following micro-control steps sequentially through its built-in logic decision unit:
[0087] S401, the main controller extracts the heat flux attenuation rate at the source and executes the preset attenuation trigger condition logic identification. Conventional hydraulic transient disturbances in industrial fluid pipelines can easily induce small fluctuations in data. If the action is based solely on the extreme value exceeding the limit of a single parameter at a single moment, it will cause the electric three-way regulating valve to generate high-frequency mechanical oscillation switching and shorten the physical life of the equipment.
[0088] To address this issue, as a preferred approach, the main controller introduces a multi-dimensional timing delay determination mechanism. Specifically, the main controller monitors the sign and amplitude of the heat flux decay rate at the source end in real time. When it detects that the instantaneous heating power is decreasing, i.e., the heat flux decay rate at the source end is negative, and the absolute value of the heat flux decay rate at the source end is greater than the calibrated critical threshold for heat flux decay, the main controller starts its internal continuous cycle counter.
[0089] The critical threshold for heat flux decay is a physical constant derived from the product of the collector's rated output power and the inherent heat loss rate of the system piping. Only when the above-mentioned amplitude exceeding the limit continues for a preset number of sampling periods will the main controller finally determine that the solar collector has lost its ability to independently maintain heating.
[0090] In this embodiment, the preset number of sampling cycles is usually calibrated based on the hydraulic inertia time constant of the fluid pipeline network and the mechanical action delay of the electric three-way regulating valve. Its value range is set between 3 and 5 cycles to filter out occasional hydraulic pulse interference.
[0091] After confirming that the above-mentioned joint judgment conditions are met, the main controller triggers a soft-switching command for the electric three-way regulating valve. Upon receiving the command, the electric three-way regulating valve actuates, cutting off the direct supply pipeline and guiding the medium flowing out of the solar collector subsystem into the plate heat exchanger of the air source heat pump unit as an auxiliary heat source. This switching process, at the physical level, transforms the near-failure high-temperature direct heating into a low-grade heat source extraction condition for the heat pump unit, thereby expanding the effective operating boundary of the entire unit.
[0092] S402, during the transition period of the operating condition when the flow path is switched, the traditional temperature deviation proportional integral derivative control algorithm cannot fill the transient heat vacuum generated by the system in time due to the inherent phase lag and integral saturation effect.
[0093] To address this control delay, the main controller calculates the initial startup frequency command based on the combined constraints of the source-side heat flux decay rate and the load-side heat capacity hysteresis integral. In this embodiment, this initial startup frequency command is set as the algebraic sum of the base sustaining frequency, the decay compensation, and the heat capacity suppression. The frequency mapping algebraic formula internal to the main controller is expressed as:
[0094] ;
[0095] In this mapping relationship, The representation system in the current number The initial start frequency command calculated from each sampling period is in Hz. The base sustaining frequency, which is determined by a table lookup of the current outdoor base temperature, is used to provide a reference refrigerant flow rate to sustain the heat dissipation of the building base. Characterizes the attenuation compensation gain coefficient; Characterizes the gain coefficient of heat capacity suppression.
[0096] From a dimensional analysis perspective, since the left side of the equation represents a frequency physical quantity (Hz), the right side of the equation... The power change rate (W / s) The integral of temperature and time (°C·s) is therefore and Essentially, it includes the energy-speed dimension conversion matrix attribute of the system under specific operating conditions.
[0097] In this embodiment, The value range is [0.05, 0.2]. The value range is [0.01, 0.05].
[0098] Based on the physical mechanism of this formula, the attenuation compensation amount is the value in the formula. This term is positively correlated with the absolute value of the heat flux decay rate at the source. When the heat on the solar side drops sharply, this term increases rapidly, driving the variable frequency compressor to actively increase its speed to relay energy.
[0099] The heat capacity suppression amount is the one in the formula. This term is positively correlated with the lag integral of the load-side heat capacity. By introducing this negative subtraction term, the system utilizes the building's own heat storage capacity to numerically offset the frequency increase trend of the variable frequency compressor caused by heat decay. This multivariate parameter game mechanism effectively suppresses the excessively high frequency of ineffective starts of the variable frequency compressor during the transition period of the operating condition, preventing a surge in energy consumption caused by over-response.
[0100] The above gain coefficient and The specific setting value can be obtained by conducting step load response tests on buildings for specific applications and combining expert experience rules. The conventional parameter identification process is a well-known technology in this field and will not be elaborated here.
[0101] S403, to ensure the physical safety of the variable frequency compressor under extremely cold or harsh power grid conditions, the main controller, after receiving the initial start-up frequency command, is configured to forcibly execute a hardware safety limiting program. The main controller will calculate... The values are compared with the minimum oil return frequency lower limit and the maximum torque frequency upper limit set by the factory of the variable frequency compressor.
[0102] If the calculated value falls below the lower frequency limit, it will be clamped at that lower limit to ensure normal oil circulation of the refrigerant within the system; if the calculated value exceeds the upper frequency limit, it will be clamped at the upper frequency to prevent the compressor motor coil from overloading and burning out. The final frequency command after safety limiting is sent by the main controller to the inverter drive module of the variable frequency compressor to execute the specific heating compensation action.
[0103] In the process of performing the above-mentioned smooth switching between dual operating conditions and compressor feedforward mapping control, in order to avoid the potential physical damage risk of the cross-medium heat exchange link, this embodiment elaborates on the cross-medium anti-freeze interlock control and extreme condition safe exit mechanism inside the main controller.
[0104] When the system is operating in a series auxiliary heating loop, the plate heat exchanger of the air source heat pump unit acts as an evaporator, continuously absorbing heat from the warm water on the solar collector side. If the intake air volume of the variable frequency compressor exceeds the heat provided by the water side, the local temperature on the water side inside the plate heat exchanger will drop sharply. Once this local temperature falls below the fluid's freezing point, phase change icing will occur, leading to physical expansion and cracking of the heat exchanger.
[0105] To achieve a rapid anti-freeze response, relying solely on feedback from the water temperature sensor suffers from significant thermal inertia hysteresis. Based on the aforementioned physical causal relationship, as a preferred approach, the main controller uses the refrigerant suction pressure as the feedforward monitoring parameter. The main controller then executes the following safety control steps sequentially:
[0106] Before performing specific calculations, the S501 main controller uses a low-level timer hard interrupt to timestamp the sensor data on the multi-channel communication bus to ensure the rigor of data processing. This ensures that all parameters involved in the calculation belong to the same physical time segment.
[0107] After data alignment, the main controller extracts the suction pressure data after low-pass filtering and calculates the time derivative of the suction pressure. Based on the thermodynamic saturation properties of the refrigerant, the drop in suction pressure directly characterizes the sudden decrease in evaporation temperature. The pressure decay rate calculation model built into the main controller is expressed as:
[0108] ;
[0109] In this relation Characterizes the inspiratory pressure decay rate calculated at the current moment, in MPa / s; Characterize the current number The effective filtered value of inhalation pressure obtained in each sampling period; This represents the effective filtered value of the intake pressure from the previous cycle. To ensure the integrity of the underlying algorithm logic, the main controller also incorporates a hardware bypass to prevent overflow during division.
[0110] When the time interval between two consecutive pressure samplings is less than the system tolerance threshold due to physical anomalies such as communication congestion, the main controller suspends the current division operation and directly maintains the historical calculation result of the previous cycle, thereby avoiding processor abnormal reset failure caused by the denominator approaching zero.
[0111] S502, the main controller performs multi-dimensional water-side anti-freeze protection adjustment based on the intake pressure decay rate. To avoid frequent system start-ups and shutdowns caused by single-point false alarms from sensors due to transient voltage fluctuations in the power grid, the trigger condition for this anti-freeze protection action is set to be based on a weighted logic judgment of multiple parameters.
[0112] Specifically, the main controller synchronously compares the suction pressure decay rate with the collector outlet water temperature. When it is determined that the suction pressure decay rate is less than the set safe decay threshold and the collector outlet water temperature is approaching the set warning temperature threshold, the main controller sends a speed increase command to the variable frequency collector side circulation pump.
[0113] In this embodiment, the range of the aforementioned safety attenuation threshold is determined based on the pressure-enthalpy curve characteristics of the corresponding refrigerant in the low-pressure region, and is typically set within the range of [−0.05, −0.01] MPa / s. A negative value and an absolute value exceeding the limit indicate an accelerating downward pressure trend.
[0114] The warning temperature threshold is preset based on the freezing point of the working fluid and the heat transfer temperature difference of the heat exchanger. When the working fluid is a conventional aqueous solution, the warning temperature threshold is usually calibrated to 5℃. The technical purpose of issuing a speed-up command to the circulating pump is to increase the circulation flow rate of the warm water on the collector side, thereby forcibly increasing the heat carried into the plate heat exchanger, thus smoothing out the sharp drop in temperature on the evaporator side and achieving a thermodynamic dynamic balance between the refrigerant side and the water side.
[0115] In S503, after the variable frequency solar collector-side circulation pump accelerates, the main controller initiates an extreme condition monitoring program to determine if the system is facing heat depletion. Under certain severe conditions, the solar collector loses external heat supply. At this time, even if the collector-side circulation pump operates at full load, it cannot reverse the continuous downward trend of water temperature.
[0116] The main controller monitors the collector outlet water temperature in real time. When the outlet water temperature drops below the ultimate freezing threshold, and this over-limit state persists for a set safety confirmation time window, the main controller determines that the system has entered an extreme operating condition. For pure water media systems, the ultimate freezing threshold is typically set within the range of [2,3]℃, which approximates the physical freezing point while retaining the necessary tolerance for sensor measurement errors. The aforementioned safety confirmation time window is derived based on the effective volume of the heat exchanger water side and the minimum allowable flow rate of the pipe network, and is usually calibrated within the range of 10–15 seconds to filter out brief water temperature fluctuations caused by air bubbles passing through the sensor probe in the pipe.
[0117] Upon confirming the entry into extreme operating conditions, the main controller sequentially issues a combination of safety exit commands. The main controller sends a reset signal to the electric three-way regulating valve, driving the mechanical valve core to switch the fluid medium back to the first output end (i.e., the solar direct heating circuit), using the water pump to maintain the minimum antifreeze circulation flow rate of the fluid pipeline network, and cutting off the physical heat exchange connection between the water system and the plate heat exchanger.
[0118] During the synchronous interaction process of cutting off the water circuit, the main controller reconfigures the drive logic of the four-way reversing valve and outdoor fan inside the air source heat pump unit, switching the suction side of the variable frequency compressor to the finned heat exchanger on the outdoor air side. Through the above control timing, the system exits the dual-condition coupling mode and transitions to an independently operating air source heat pump heating state. This safe exit mechanism ensures the physical safety boundary of the core heat exchange hardware in extremely cold environments while utilizing the low-grade waste heat of the solar system.
[0119] Based on the hardware topology and physical modeling of each underlying control module constructed in the foregoing embodiments, this embodiment provides a macro-level overview of the overall control method for a smart heating system based on an air source heat pump.
[0120] See attached document Figure 2 In this embodiment, under the scheduling of the underlying real-time operating system, the main controller executes the following system-level control steps sequentially according to the set basic control cycle:
[0121] In S601, the main controller performs the acquisition of multi-source heterogeneous data and timing anti-interference preprocessing. During this stage, the main controller drives the external communication interface module to read real-time physical parameters fed back from the sensor network in parallel. To ensure the timing accuracy of cross-bus data and avoid misjudgments of system status caused by asynchronous sampling, the main controller uses an internal hardware timer interrupt to force timestamp alignment of parameters such as inlet and outlet water temperatures, collector-side flow rate, and suction pressure.
[0122] After alignment is completed, the main controller sequentially performs data over-limit threshold clamping and discretization first-order low-pass smoothing, thereby providing the upper-level control algorithm with a clean data stream that is continuous, free of singular values and has real physical causal relationships.
[0123] S602, after acquiring valid filtered data, the main controller calls the source-load dual-end feedforward parameter calculation task. Based on the thermodynamic energy conservation principle, the main controller calculates the instantaneous heating power of the current system and uses a discrete backward differential algorithm with a bypass protection mechanism to extract the source-end heat flux attenuation rate, in order to avoid the risk of computational overflow due to communication congestion causing the time increment to approach zero.
[0124] Based on this, the main controller performs heat capacity hysteresis integral calculations with an anti-saturation clamping mechanism for the building's environmental load side. This step constructs the feedforward physical boundary of the entire control system at the software algorithm level, accurately quantifying the dynamic deviation between the source-end heating capacity slippage and the actual energy demand at the load end.
[0125] S603, based on the extracted source-load dual-end feedforward parameters, the main controller performs conditional discrimination with dual-condition feedforward triggering. The main controller compares the negative absolute value of the source-end heat flux decay rate with the set critical threshold for heat flux decay. By introducing a joint judgment constraint of multi-cycle continuous limit exceedance, the main controller effectively filters out pseudo-attenuation signals caused by transient hydraulic disturbances in the pipeline network.
[0126] When it is confirmed that the solar collector has lost its ability to independently maintain heating, the main controller sends a flow path soft switching command to the electric three-way regulating valve to smoothly reconstruct the system thermodynamic architecture to a low-grade heat source auxiliary extraction mode.
[0127] S604, during the transition period of system operating conditions, the main controller initiates the compressor's multivariable mapping control logic in parallel. To overcome the inherent phase lag of traditional feedback control,
[0128] As a preferred approach, the main controller substitutes the source-side heat flux attenuation rate and the load-side heat capacity hysteresis integral obtained from the aforementioned steps into a multivariable frequency mapping model. Based on the dimensional conversion properties of energy and rotational speed, this model calculates the algebraic sum of the base sustaining frequency, attenuation compensation, and heat capacity suppression. The main controller further compares this calculation result with the upper and lower limits of the compressor's factory-set mechanical safety frequency and implements absolute clamping, ultimately generating a safe and reliable initial start-up frequency command and sending it to the variable frequency compressor drive module.
[0129] Throughout the entire lifecycle of the S605 under dual-condition coupled operation, the main controller continuously performs cross-medium anti-freeze interlock control tasks. Due to the significant time lag effect in cross-medium heat transfer, the main controller compares the suction pressure decay rate with the collector outlet water temperature in real time.
[0130] When the freezing point approach warning conditions are met based on multi-dimensional weighted judgment, the main controller prioritizes increasing the speed of the variable frequency heat collector side circulation pump to forcibly enhance heat transfer. If the extreme over-limit state persists within the set safety confirmation time window, the main controller sequentially drives the electric three-way regulating valve and four-way reversing valve to perform hardware reset, cutting off the cross-medium heat exchange link. After the above timing logic control, the system safely exits to the independent air source heat pump normal heating state.
[0131] Specific application examples:
[0132] To further verify the engineering effectiveness of the smart heating system and control method based on air source heat pump proposed in this invention in a real physical environment, this section provides detailed application examples and experimental comparison verification results in conjunction with a specific application scenario.
[0133] In this embodiment, the application scenario is set as a building with a floor area of 150m² in North my country. 2 The test environment consisted of a detached house. The outdoor base temperature was maintained at -15℃, and the indoor target heating temperature was set at 20℃. The building's wall structure had a large thermal inertia, and the system used vacuum tube solar collectors paired with a variable frequency air source heat pump unit with a rated heating capacity of 12kW.
[0134] System-level sampling period The filter time constant is set to 2 seconds for the inlet and outlet water temperature sensors. The value is 10s. Based on the formula derivation, the filter coefficients inside the main controller... The calculated value is approximately 0.167. This parameter is set to remove high-frequency electromagnetic interference from the water pump inverter while preserving the true phase of the slowly changing thermodynamic signal.
[0135] At 14:30 on the day of the test, the test environment was suddenly blocked by thick cloud cover, causing a sharp drop in solar irradiance. The main controller continuously collected data and performed calculations based on the inlet and outlet water temperature difference and the flow rate on the collector side. Real-time feedback, and the instantaneous heating power calculated The power output dropped rapidly from 8.5kW to 3.2kW within five minutes.
[0136] At this point, the differential algorithm inside the main controller captures the continuous negative source-end heat flux decay rate. When the decay rate exceeds the set critical threshold for heat flow decay (-50W / s) for five consecutive cycles, the main controller issues a flow path switching command, the electric three-way regulating valve is activated, and the system is smoothly reconfigured from direct solar heating to a series auxiliary heating loop.
[0137] During the switching transition period, the main controller synchronously executes multivariable frequency mapping control.
[0138] Based on the current outdoor base temperature, the compressor base sustaining frequency is determined by referring to a table. The frequency is 45Hz. At this time, although the heat source is sharply reduced, the actual indoor temperature remains high due to the building's thermal inertia. The temperature dropped only slightly from 20.2℃ to 19.8℃. If traditional temperature feedback control were used, the controller would not drive the compressor to increase its frequency significantly due to the small temperature difference.
[0139] In the multivariate model of this invention, the absolute value of the source-end heat flux decay rate... Surge, multiplied by attenuation compensation gain factor (Set to 0.15), which constitutes the feedforward compensation term; at the same time, the heat capacity hysteresis integral... Since the temperature difference has not yet accumulated and the value is relatively small, it is multiplied by the previous hysteresis correction gain factor. (Set to 0.02), forming a small positive fine-tuning base.
[0140] Substitute into the integrated control model The main controller instantly generated an initial start-up frequency command of approximately 56Hz. Based on this command, the inverter compressor accelerated in advance, actively filling the heat vacuum caused by the fading of solar energy before the room temperature experienced a significant drop.
[0141] Experimental comparison and effect verification explanation:
[0142] To quantitatively verify the technical effectiveness of the smart heating system based on air source heat pump proposed in this invention, a control system using traditional temperature deviation PID closed-loop control was built on a physical experimental platform. Parallel tests were conducted under the same sudden meteorological disturbance conditions (outdoor temperature -15℃, sudden thick cloud cover), and the following multi-dimensional comparison results were obtained:
[0143] Reference Figure 3 and Figure 4 , Figure 3 The vertical axis represents the converted value of the product of the collector flow rate and the temperature difference between the inlet and outlet water (i.e., instantaneous power, unit: kW). Figure 4 The vertical axis represents the heat flux decay rate at the source (unit: W / s), and the horizontal axis represents time. The data trajectory in the graph shows that when a sudden cloud cover disturbance occurs in the external environment, the instantaneous power rapidly drops from 8.5 kW to 3.2 kW within 5 minutes, leading to… Figure 4 The heat flux decay rate surges sharply in the negative direction. When the heat flux decay rate continuously exceeds the calibrated decay trigger threshold (-50W / s), the system precisely issues a flow path switching command at the action time. This verifies that the differential algorithm of this invention has a keen ability to capture and feedforward trigger early signs of heat depletion at the source.
[0144] Reference Figure 5 In the figure, the vertical axis represents indoor ambient temperature (°C), and the horizontal axis represents time (h). The central horizontal line marks the target temperature baseline of 20°C. The solid line in the figure represents the temperature response trajectory of the feedforward mapping control strategy of this invention, while the dashed line represents the temperature response trajectory of the traditional PID feedback control strategy. The figure shows that after an environmental disturbance, the dashed line representing the traditional PID exhibits a significant hysteresis drop, reaching a low of 17.4°C, subsequently triggering system overload heating and causing the room temperature to fluctuate significantly between 17.4°C and 22.5°C. In contrast, the solid line representing this invention, after experiencing an initial weak disturbance, is smoothed out within a narrow band between 19.5°C and 20.5°C. This indicates that this invention, utilizing source-end attenuation as a feedforward parameter, reduces the steady-state fluctuation variance by 78.3% compared to the traditional PID, eliminating the control hysteresis effect caused by building heat capacity.
[0145] Reference Figure 6 In the graph, the vertical axis represents the compressor operating frequency (Hz), and the horizontal axis represents time (h). The solid line in the graph represents the frequency output response of the system of this invention, while the dashed line represents the frequency output response of the traditional PID controller. Analysis of the response trajectory in the graph shows that the dashed line, representing the traditional PID controller, frequently triggers the maximum frequency limit (90Hz) operation and shutdown hibernation under large temperature differences caused by feedback lag, exhibiting typical lag-induced large start-stop oscillation characteristics, accompanied by severe mechanical shock. In contrast, the solid line, representing the system of this invention, exhibits an early start-up and smooth transition characteristic during the thermal vacuum period, with the highest peak frequency suppressed to around 65Hz.
[0146] This demonstrates that the frequency command output of this invention achieves stepless smooth transition, effectively avoiding overcurrent heat loss in the inverter and compressor motor under extreme operating conditions. In a 72-hour harsh operating condition comparison test, the cumulative comprehensive power consumption of this system was reduced by 14.6% compared to the control group's heat pump unit, showcasing excellent energy-saving and emission-reduction effects.
[0147] Reference Figure 7 In the graph, the left vertical axis represents the time derivative of the suction pressure (MPa / s), the right vertical axis represents the collector outlet water temperature (°C), and the horizontal axis represents time (s). The graph also simultaneously marks the lower limit of the safe decay threshold range (-0.03MPa / s) and the ultimate freezing threshold (3°C). The data trajectory in the graph shows that during the extreme testing phase with extreme cold, no light, and a forced low pump flow rate, when the main controller detected the suction pressure time derivative on the left axis rapidly declining and falling below the threshold, the water-side outlet water temperature reading on the right axis remained stagnant at 5.5°C due to the physical heat transfer delay of the thermocouple tube wall. At this point, the system did not wait for the water temperature to actually drop to freezing point but immediately increased the pump speed based on the pressure feedforward signal. Within the following 30 seconds, the downward trend of the water-side temperature was successfully contained and clamped back.
[0148] This convergence process verifies the forward-looking nature of the cross-medium anti-freeze interlock control mechanism of this invention, avoids physical ice blockage and cracking of the microchannels of the plate heat exchanger, and ensures the high reliability of the system in the industrial field.
Claims
1. A smart heating system based on an air source heat pump, characterized in that, include: Solar thermal collector subsystem; An air source heat pump unit includes a variable frequency compressor and an auxiliary heat exchange side, wherein the refrigerant end of the auxiliary heat exchange side is connected to the suction side of the variable frequency compressor. A flow path switching device is installed between the solar thermal collector subsystem, the auxiliary heat exchange side of the air source heat pump unit, and the fluid circuit where the heating terminal is located, and is used to control the flow direction of the fluid medium. A sensor network is used to collect source-side state parameters of the solar thermal collector subsystem and load-side state parameters of the building environment. The main controller is used to calculate the heat flux decay rate at the source end based on the source end state parameters, and to calculate the load-side heat capacity hysteresis integral based on the load end state parameters and the set target temperature. When it is determined that the heat flow attenuation rate at the source meets the preset attenuation trigger condition, the flow path switching device is controlled to operate, and the medium flowing out of the solar collector subsystem is introduced into the auxiliary heat exchange side as an auxiliary heat source. Based on the combined constraints of the source-side heat flux attenuation rate and the load-side heat capacity hysteresis integral, the initial start-up frequency command is calculated and sent to the variable frequency compressor to perform heating compensation.
2. The intelligent heating system based on an air source heat pump according to claim 1, characterized in that, The system has a specific fluid connection topology: The solar thermal collector subsystem includes a solar thermal collector, and the outlet end of the solar thermal collector is connected to a heat collection side circulation pump through a pipeline. The flow path switching device is an electric three-way regulating valve. The output end of the heat collection side circulation pump is connected to the input end of the electric three-way regulating valve through a pipeline. The first output end of the electric three-way regulating valve is connected to the heating terminal through a direct supply pipeline. The second output end of the electric three-way regulating valve is connected to the air source heat pump unit through a series pipeline. The auxiliary heat exchange side is a plate heat exchanger, and the medium input end of the plate heat exchanger is connected to the second output end of the electric three-way regulating valve. The source-side status parameters specifically include the inlet and outlet water temperatures of the solar collector and the flow rate on the collector side. The load-side status parameters specifically include indoor ambient temperature.
3. A smart heating system based on an air source heat pump according to claim 2, characterized in that, The specific logic for the main controller to calculate the source-end heat flux attenuation rate is as follows: The instantaneous heating power is calculated by multiplying the difference between the inlet and outlet water temperatures by the flow rate on the collector side and the physical properties of the medium, and the first derivative of the instantaneous heating power with respect to time is obtained to obtain the heat flow attenuation rate at the source end.
4. A smart heating system based on an air source heat pump according to claim 3, characterized in that, The specific logic by which the main controller determines that the source-end heat flux attenuation rate meets the preset attenuation trigger condition is as follows: When the instantaneous heating power is detected to be decreasing, i.e. the heat flow attenuation rate at the source is negative and the absolute value of the heat flow attenuation rate at the source is greater than the calibrated critical threshold for heat flow attenuation, and this continues for a preset number of sampling cycles, it is determined that the solar collector has lost its ability to independently maintain heating, and a soft switching command for the flow path of the electric three-way regulating valve is triggered.
5. A smart heating system based on an air source heat pump according to claim 2, characterized in that, The specific logic for the main controller to calculate the hysteresis integral of the load-side heat capacity is as follows: Calculate the dynamic difference between the set target temperature and the indoor ambient temperature, and perform discrete-time integration on the dynamic difference within a preset sliding time window to obtain the load-side heat capacity hysteresis integral.
6. A smart heating system based on an air source heat pump according to claim 1, characterized in that, The specific logic for the main controller to calculate the initial startup frequency command is as follows: The initial startup frequency command is set to the algebraic sum of the base maintenance frequency, attenuation compensation, and thermal capacity suppression. Wherein, the attenuation compensation amount is positively correlated with the absolute value of the source-end heat flow attenuation rate, and the heat capacity suppression amount is positively correlated with the load-side heat capacity hysteresis integral. The heat capacity suppression amount corresponding to the load-side heat capacity hysteresis integral is used to numerically offset the frequency increase trend of the variable frequency compressor based on heat attenuation, thereby suppressing the excessively high frequency ineffective start-up of the variable frequency compressor during the operating condition transition period.
7. A smart heating system based on an air source heat pump according to claim 2, characterized in that, The heat collector side circulation pump is a variable frequency heat collector side circulation pump, and the sensor network is also equipped with a suction pressure sensor for collecting the suction pressure of the variable frequency compressor. The main controller has a cross-media anti-freeze interlock control task internally configured. The specific execution logic of the cross-media anti-freeze interlock control task is as follows: During the operation of the variable frequency compressor at the initial start-up frequency command and while it is extracting heat, the first derivative of the suction pressure of the variable frequency compressor with respect to time is calculated synchronously to obtain the suction pressure decay rate. When it is determined that the suction pressure decay rate is less than the set safety decay threshold and the collector outlet water temperature is close to the set warning temperature threshold, the main controller sends a speed increase command to the variable frequency collector side circulation pump to perform water-side anti-freeze protection adjustment.
8. A smart heating system based on an air source heat pump according to claim 7, characterized in that, After the variable frequency heat collector side circulating pump speeds up, the main controller starts the extreme condition monitoring program. The specific control logic is as follows: The system monitors the outlet water temperature of the solar collector in real time. When the outlet water temperature of the solar collector drops below the limit freezing threshold and the over-limit state is maintained for a set safety confirmation time window, the system is determined to have entered the extreme operating condition. After confirming that the extreme working condition has been entered, the main controller sends a reset electrical signal to the electric three-way regulating valve to switch the fluid medium back to the first output terminal; The drive logic of the four-way reversing valve and the outdoor fan inside the air source heat pump unit is reconstructed simultaneously, so that the suction side of the variable frequency compressor switches to the finned heat exchanger on the outdoor air side and exits the dual-condition coupling mode.
9. A smart heating system based on an air source heat pump according to claim 1, characterized in that, Before the main controller calculates the source-side heat flux attenuation rate and the load-side heat capacity hysteresis integral, the main controller performs first-order low-pass smoothing on the raw time-series data collected by the sensor network using an internally set digital filtering algorithm. After filtering out high-frequency interference noise, the filtering parameters are extracted and substituted into the subsequent calculation steps.
10. A control method for a smart heating system based on an air source heat pump, characterized in that, The smart heating system based on an air source heat pump, as described in any one of claims 1 to 9, comprises the following steps: The sensor network synchronously collects the source-side state parameters of the solar thermal collector subsystem and the load-side state parameters of the building environment in real time. The main controller calculates the heat flux attenuation rate at the source end based on the source end state parameters; Based on the load-side state parameters and the set target temperature, the load-side heat capacity hysteresis integral is calculated by time integration. The main controller determines whether the heat flow attenuation rate at the source meets the preset attenuation trigger condition. If it does, it sends an action command to the flow path switching device to introduce the medium flowing out of the solar collector subsystem into the auxiliary heat exchange side of the air source heat pump unit. The main controller calculates the initial start-up frequency command based on the combined constraints of the source-side heat flux attenuation rate and the load-side heat capacity hysteresis integral, and sends it to the variable frequency compressor to perform heating compensation.