A photovoltaic direct-drive heat pump phase change heat storage system and a control method thereof

Abstract

The application provides a photovoltaic direct-drive heat pump phase change heat storage system and a control method thereof, and the system comprises a photovoltaic assembly, an intelligent controller, an air source heat pump, a phase change heat storage unit and a radiation-convection coupling terminal, wherein the photovoltaic assembly is electrically connected with an input end of the intelligent controller, an output end of the intelligent controller is electrically connected with a compressor power supply end of the air source heat pump, the air source heat pump is connected with the phase change heat storage unit and the radiation-convection coupling terminal through pipelines respectively, and the intelligent controller is signal connected with the photovoltaic assembly, the air source heat pump, the phase change heat storage unit and the radiation-convection coupling terminal respectively, for monitoring operation parameters of each component and controlling operation states. The application can accurately control each working mode, and the heat storage efficiency is improved correspondingly.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic energy storage technology, and in particular to a photovoltaic direct-drive heat pump phase change thermal energy storage system and its control method. Background Technology

[0002] Currently, the combination of photovoltaics and heat pumps still relies on AC / DC conversion and grid transmission, and has not formed an efficient photovoltaic direct drive mode. This not only results in significant power conversion and transmission losses, but also leads to a low on-site absorption rate of renewable energy, which seriously restricts the large-scale application of photovoltaic energy in the field of building heating.

[0003] Among them, air source heat pumps are the preferred equipment for building heating, but traditional systems rely on municipal power grids for power supply. Even when combined with photovoltaics, they often lack phase change thermal storage modules and direct drive technology. The intermittency and volatility of photovoltaic power generation do not match the spatiotemporal heat load of buildings, and the lack of energy buffer regulation from phase change thermal storage makes it difficult to guarantee the continuity of heating. At the same time, traditional single heating terminals cannot flexibly adapt to the output of photovoltaic direct drive and the state of thermal storage release, affecting indoor thermal comfort.

[0004] Furthermore, the existing control methods of related systems are mostly simple switching or single parameter adjustment, which are neither adapted to the characteristics of direct photovoltaic operation nor have a coordinated control mechanism for the energy supply side (photovoltaic power generation), storage side (phase change thermal storage), and demand side (building heating) been established. It is difficult to take into account the energy-saving advantages of photovoltaics, the peak shaving and valley filling effect of phase change thermal storage, system operating efficiency and economic cost, which limits the practical application of such systems. Corresponding coordinated control solutions are urgently needed. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a photovoltaic direct-drive heat pump phase change thermal energy storage system and its control method to solve the problems of large energy loss, low renewable energy absorption rate, poor heating continuity, and crude control methods in the prior art.

[0006] The first aspect of the present invention proposes: A photovoltaic direct-drive heat pump phase change thermal energy storage system includes: photovoltaic modules, an intelligent controller, an air source heat pump, a phase change thermal energy storage unit, and a radiation-convection coupling terminal, wherein: The photovoltaic module is electrically connected to the input terminal of the intelligent controller, and the output terminal of the intelligent controller is electrically connected to the power supply terminal of the air source heat pump compressor. The air source heat pump is connected to the phase change thermal storage unit and the radiation-convection coupling terminal through pipelines. The intelligent controller is connected to the photovoltaic module, the air source heat pump, the phase change thermal storage unit and the radiation-convection coupling terminal for signal monitoring of the operating parameters of each component and control of the operating status.

[0007] The beneficial effects of the present invention are: (1) The present invention constructs a "photovoltaic-heat pump" direct drive channel to realize the direct drive of photovoltaic DC power to the heat pump compressor, reduce the energy loss of AC-DC conversion and grid transmission links, greatly improve the on-site consumption rate of renewable energy, reduce the overall energy consumption of the system and the energy cost of users, and has both environmental protection and economic value.

[0008] (2) The present invention introduces a phase change thermal storage unit, which utilizes the high latent heat characteristics of phase change materials to dynamically mitigate the spatiotemporal contradiction between the intermittency and volatility of photovoltaic power generation and the building heat load, ensuring the system's continuous heating capacity when there is no sunshine or insufficient photovoltaic output, and significantly improving the system's operational stability and reliability.

[0009] (3) The present invention adopts an adaptive control algorithm based on multi-parameter feedback to achieve seamless and smooth switching of multiple modes such as "photovoltaic direct-drive heating", "photovoltaic thermal storage", "thermal storage and heat release heating" and "hybrid complementarity", ensuring that the system always operates in the most efficient way, maximizing the direct use of renewable energy, while maintaining a high level of comfort in the indoor thermal environment, and realizing intelligent coordination of the entire process of energy supply, storage and demand.

[0010] Furthermore, the photovoltaic module is used to convert solar energy into direct current, and its output end is connected to the input end of the intelligent controller through a wire to provide renewable energy power to the system.

[0011] Furthermore, the intelligent controller is the core control unit with a built-in adaptive control algorithm. Its signal ports are respectively connected to the photovoltaic power sensor, the temperature sensor of the phase change thermal storage unit, the indoor and outdoor temperature and humidity sensor, and the terminal load sensor. Its output terminal is electrically connected to the air source heat pump compressor, the solenoid valves of each pipeline, and the regulating device of the radiation-convection terminal to realize parameter monitoring and equipment control.

[0012] Furthermore, the air source heat pump includes a compressor, a four-way reversing valve, an outdoor heat exchanger, and an electronic expansion valve. The power supply terminal of the compressor is connected to the output terminal of the intelligent controller and receives photovoltaic DC power for driving. The air source heat pump is connected to the phase change heat storage unit and the radiation-convection coupling terminal through pipelines. The pipelines are equipped with solenoid valves for switching the fluid flow direction and branch on / off.

[0013] Furthermore, the phase change thermal storage unit incorporates a high latent heat phase change material and a heat exchange coil. The two ends of the heat exchange coil are connected to the air source heat pump via pipelines, which is used to store surplus photovoltaic energy and release energy to supplement heating.

[0014] Furthermore, the integrated radiant plate and convection heat exchanger at the radiation-convection coupling end are connected to the air source heat pump and the phase change heat storage unit through pipelines, so as to dynamically adjust the ratio of radiation and convection heating according to the indoor load.

[0015] The second aspect of the present invention proposes: A control method for a photovoltaic direct-drive heat pump phase change thermal energy storage system, applied to the photovoltaic direct-drive heat pump phase change thermal energy storage system as described above, the method comprising: Step 1: Input parameters, including photovoltaic power, phase change thermal storage unit heat storage / release status, indoor temperature, outdoor temperature, indoor humidity, outdoor humidity, building heat load, and terminal operation parameters; Step 2: Establish a multi-parameter feedback model. The multi-parameter feedback model takes the parameters as input and outputs the optimal operating state parameters of the system through data fitting and algorithm optimization. The optimal operating state parameters include heat pump output, phase change unit heat storage / release rate, and terminal heating ratio. Step 3: Construct four operating modes and establish system energy efficiency models for each mode; Step 4: Calculate the maximum energy efficiency ratio (COPmax) of the system using an adaptive control algorithm. The maximum energy efficiency ratio is the maximum value among the calculation results of the four energy efficiency models. Step 5: Control the operation of each component according to the operating mode corresponding to the maximum energy efficiency ratio to achieve seamless mode switching.

[0016] Furthermore, the system energy efficiency model specifically includes: The energy efficiency model COPw for photovoltaic direct-drive heating mode reflects the ratio of system heating capacity to power consumption during photovoltaic direct drive. The COPs energy efficiency model of photovoltaic thermal storage mode reflects the ratio of system thermal storage efficiency to energy consumption when photovoltaic surplus is achieved. The energy efficiency model COPr for the thermal storage and release heating mode reflects the ratio of system heating efficiency to energy consumption when the phase change unit releases heat. The COPh energy efficiency model of the hybrid complementary mode reflects the overall energy efficiency ratio of the system when photovoltaic and phase change units operate in tandem.

[0017] Furthermore, the photovoltaic direct-drive heating mode is as follows: the photovoltaic power meets the load of the air source heat pump and the building's heat demand; the intelligent controller controls the branch of the phase change thermal storage unit to close; the photovoltaic DC power directly drives the heat pump compressor; the heat pump compressor delivers heat to the radiation-convection coupling terminal; and the radiation-convection coupling terminal provides heat through coordinated radiation and convection. The photovoltaic thermal storage mode is as follows: the photovoltaic power is greater than the load of the air source heat pump and the instantaneous heat demand of the building; the intelligent controller controls the terminal branch to adjust as needed; the air source heat pump delivers heat to the phase change thermal storage unit; and the phase change material absorbs latent heat to store energy. The heat storage and release heating mode is as follows: when there is no sunshine or insufficient photovoltaic power, the phase change heat storage unit releases the stored latent heat, and the intelligent controller controls whether the air source heat pump is started according to the heat load demand. The heat is released into the room through the radiation-convection coupling terminal. The hybrid complementary mode is as follows: the photovoltaic power part meets the heat demand, the phase change thermal storage unit releases energy, and works in conjunction with the photovoltaic direct-drive heat pump to deliver heat to the terminal, dynamically adjusting the output ratio of the two.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the photovoltaic direct-drive heat pump phase change thermal energy storage system provided in the first embodiment of the present invention; Figure 2 A flowchart of a photovoltaic direct-drive heat pump phase change thermal energy storage system control method provided in the third embodiment of the present invention.

[0020] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0022] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] like Figure 1As shown, this is the photovoltaic direct-drive heat pump phase change thermal storage "radiation-convection" terminal system proposed in the embodiment of the present invention. This photovoltaic direct-drive heat pump phase change thermal storage "radiation-convection" terminal system constructs an integrated heating system of "photovoltaic direct drive-phase change thermal storage-precision heating" through the coordinated cooperation of photovoltaic modules, intelligent controllers, air source heat pumps, phase change thermal storage units and radiation-convection coupling terminals. It comprehensively solves the problems of large energy loss of photovoltaic utilization, low renewable energy absorption rate, poor heating continuity, crude control methods and insufficient indoor thermal comfort in the existing technology.

[0025] Specifically, the system includes photovoltaic modules, intelligent controllers, air-source heat pumps, phase-change thermal storage units, and radiation-convection coupling terminals. Among these, the photovoltaic modules, as the core renewable energy supply component, directly convert solar energy into direct current (DC) electricity for output. Compared to traditional photovoltaic heating systems that require an inverter to convert DC to AC and then a rectifier to DC for the heat pump, this design directly constructs a "photovoltaic-heat pump" direct-drive channel. This eliminates the intermediate steps of AC-DC conversion and grid transmission, effectively reducing energy losses during power conversion and transmission. It allows the clean energy generated by photovoltaics to directly drive the heat pump, significantly improving energy efficiency and laying the foundation for achieving low-carbon, near-zero energy consumption goals in building heating.

[0026] The photovoltaic modules are electrically connected to the input terminal of the smart controller. The selection of the modules should be adapted to the building heating load and local light conditions. In areas with abundant light resources, multiple photovoltaic modules can be connected in series or in parallel to increase the total output. In areas with average light resources, a photovoltaic tracking system can be used to improve the light collection efficiency and ensure that the photovoltaic modules can provide sufficient DC power support for the system.

[0027] As the core control unit of the entire system, the intelligent controller has a built-in adaptive control program optimized based on the PID algorithm. Its signal acquisition port is connected to the photovoltaic power sensor, the phase change thermal storage unit temperature sensor, the indoor and outdoor temperature and humidity sensor and the terminal load sensor through shielded cables. The output terminal is connected to the air source heat pump compressor, the solenoid valves of each pipeline and the radiation-convection terminal adjustment device through the relay module, so as to realize the real-time monitoring of the system operating parameters and the precise control of each actuator.

[0028] The air source heat pump, as the core heating power component of the system, includes a compressor, a four-way reversing valve, an outdoor heat exchanger, an electronic expansion valve, and indoor heat exchange piping. The compressor's power supply is directly connected to the output of the intelligent controller, receiving DC power from the photovoltaic modules to drive its operation. The refrigerant outlet of the heat pump is divided into two branches via the main pipeline. One branch connects to the inlet of the heat exchange coil of the phase change thermal storage unit via solenoid valve A, and the other branch connects to the heat exchange inlet of the radiation-convection coupling terminal via solenoid valve B. The outlet of the heat exchange coil of the phase change thermal storage unit merges with the heat exchange outlet of the radiation-convection coupling terminal via solenoid valve C, and then connects to the refrigerant return port of the air source heat pump, forming a complete refrigerant circulation loop. The on / off state of each solenoid valve is precisely controlled by the intelligent controller according to the system operating mode, enabling flexible switching of fluid flow direction and branch on / off states.

[0029] The phase change thermal energy storage unit serves as the energy buffer and regulation component of the system. It incorporates high latent heat phase change materials and spiral heat exchange coils. Both ends of the heat exchange coils are connected to the branch pipelines of the air source heat pump through flange joints. It is used to store surplus photovoltaic energy and release energy to supplement heating when photovoltaic output is insufficient.

[0030] The radiant-convection coupling terminal, serving as the system's heat release component, integrates a radiant panel and a convection heat exchanger. It connects to the piping of the air-source heat pump and phase-change thermal storage unit via a flange interface. An internal flow regulating valve is electrically connected to the output of the intelligent controller, allowing dynamic adjustment of the refrigerant flow distribution ratio between the radiant panel and the convection heat exchanger based on the indoor heat load. In this embodiment, the radiant panel is made of aluminum alloy with a corrosion-resistant and thermally conductive coating, and is ceiling-mounted to match the interior design style. The convection heat exchanger uses a finned tube structure with aluminum foil fins and a built-in low-noise centrifugal fan to improve convection heat transfer efficiency. Radiant heating is the primary method when the indoor load is low, while convection heating is the primary method when the indoor load is high.

[0031] Furthermore, the outdoor heat exchanger of the air source heat pump adopts a finned tube structure, which can precisely adjust the refrigerant flow according to the system operating conditions, ensuring that the heat pump is always in a high-efficiency operating state. All pipes are made of copper and wrapped with insulation cotton to reduce heat loss from the pipes.

[0032] In this specific implementation, the positive and negative terminals of the photovoltaic module are fixedly connected to the input terminals of the intelligent controller via copper core wires. Waterproof sealing joints are installed at the connection points to ensure safety for outdoor use. The output terminals of the intelligent controller are connected to the DC power interface of the air source heat pump compressor via copper core wires. Metal conduits are fitted over the wires to prevent damage from external forces. The installation positions of each sensor must meet the monitoring accuracy requirements: the photovoltaic power sensor is connected in series in the connection line between the photovoltaic module and the intelligent controller; the phase change thermal storage unit temperature sensor is inserted into the phase change material to a depth of not less than 200mm, avoiding the heat exchange coil; the indoor temperature and humidity sensor is installed in the center of the living room at a height of 1.5m, away from doors, windows, and heat sources; the outdoor temperature and humidity sensor is installed in the shaded area of ​​the building's exterior wall at a height of 2.0m, avoiding direct sunlight; and the terminal load sensor is installed at the water inlet pipe at the end of the radiation-convection coupling.

[0033] This invention also proposes a control method for a photovoltaic direct-drive heat pump phase change thermal storage "radiation-convection" terminal system. This control method is specifically designed to control the photovoltaic direct-drive heat pump phase change thermal storage "radiation-convection" terminal system described in the above embodiments. Through multi-parameter feedback and adaptive algorithms, it enables the system to operate efficiently and stably under different operating conditions.

[0034] In practical implementation, the first step is to input parameters. The intelligent controller collects and inputs system operating parameters in real time through various sensors, including the real-time output power P of the photovoltaic modules, the real-time temperature T_st and heat storage / release status of the phase change thermal storage unit, indoor temperature T_in, outdoor temperature T_out, indoor humidity RH_in, outdoor humidity RH_out, real-time building heat load Q, and real-time operating parameters of the radiation-convection coupling terminal, such as the proportion of radiation heating η and fan speed n. The acquisition cycle of each parameter should be reasonable to ensure the real-time nature and continuity of the data.

[0035] Step 2: Establish a multi-parameter feedback model. Based on the collected real-time parameters, the intelligent controller uses the least squares method to fit the data and construct a mapping relationship model between the system operating state and energy efficiency. This model uses T_in, Q, P, and T_st as core input variables and heat pump output Q_hp, phase change thermal storage unit heat storage / release rate Q_st, and terminal radiant heating ratio η as output variables. The output variables are optimized using the particle swarm optimization algorithm to obtain the optimal combination of system operating state parameters, ensuring that the system energy efficiency ratio is maximized while meeting indoor thermal comfort requirements.

[0036] Step 3: Construct four operating modes and establish system energy efficiency models for each mode: 1) The energy efficiency model of photovoltaic direct-drive heating mode is COPw=Q_outw / P_pv, where Q_outw is the heat supplied to the room by the system in this mode, and P_pv is the real-time output power of the photovoltaic module, which reflects the ratio of the system's heat production to the photovoltaic power consumption when photovoltaic direct drive is used. 2) Photovoltaic thermal energy storage mode energy efficiency model COPs=Q_sto / P_pv, where Q_sto is the heat storage capacity of the phase change thermal energy storage unit in this mode, and P_pv is the real-time output power of the photovoltaic module, reflecting the ratio of system thermal energy storage efficiency to photovoltaic energy consumption when photovoltaic surplus is achieved. 3) Energy efficiency model for heat storage and heat release heating mode: COPr=Q_outr / P_hp_r (if the heat pump is started) or COPr=Q_outr / 0 (if the heat pump is not started), where Q_outr is the amount of heat supplied to the room by the system in this mode, and P_hp_r is the power consumed by the heat pump in this mode, reflecting the ratio of system heating efficiency to energy consumption when the phase change unit releases heat. 4) Hybrid complementary mode energy efficiency model COPh=Q_outh / (P_pv+P_hp_h), where Q_outh is the total heat supplied to the room by the system in this mode, P_pv is the real-time output power of the photovoltaic module, and P_hp_h is the power consumed by the heat pump in this mode, reflecting the comprehensive energy efficiency ratio of the system when the photovoltaic and phase change unit are running in tandem.

[0037] Step 4: Calculate the system's maximum energy efficiency ratio COPmax using an adaptive control algorithm, i.e., COPmax=max(COPw,COPs, COPr, COPh). The intelligent controller automatically selects the optimal energy efficiency ratio and corresponding operating mode under the current working condition based on the energy efficiency model calculation results of each mode.

[0038] Step 5: Based on the operating mode corresponding to the maximum energy efficiency ratio, control the operation of each component to achieve seamless mode switching. The specific implementation process for each mode is as follows: 1. Implementation of Photovoltaic Direct-Drive Heating Mode: When the photovoltaic power sensor detects that the photovoltaic output P is greater than or equal to the rated power of the air source heat pump and P is greater than or equal to 1.1 times the building's real-time heat load Q, and the phase change heat storage unit is fully charged, the intelligent controller determines that the current optimal mode is the photovoltaic direct-drive heating mode, and then issues control commands: close solenoid valves A and C, open solenoid valve B, and control the phase change heat storage unit branch to close; the DC power output from the photovoltaic modules directly drives the air source heat pump compressor through the intelligent controller, and the compressor speed is dynamically adjusted according to the photovoltaic output; after the refrigerant is compressed and heated by the compressor, it enters the radiation-convection coupling terminal through solenoid valve B; the intelligent controller adjusts the opening of the terminal regulating valve according to the indoor heat load Q and the indoor temperature T_in, and distributes the refrigerant flow between the radiant plate and the convection heat exchanger. The refrigerant after heat exchange flows back to the outdoor heat exchanger of the air source heat pump through the manifold, and completes the circulation after being throttled and depressurized by the electronic expansion valve.

[0039] 2. Implementation of Photovoltaic Thermal Storage Mode: When the photovoltaic power sensor detects that the photovoltaic output P > the rated power of the air source heat pump and P > 1.1 times the real-time heat load Q of the building, and the phase change thermal storage unit is not fully charged, the intelligent controller determines that the current optimal mode is the photovoltaic thermal storage mode, and then issues a control command: control solenoid valve B to close appropriately, and adjust the opening according to Q to ensure that the terminal heat supply meets the indoor demand; open solenoid valves A and C; the photovoltaic DC power drives the air source heat pump compressor to run at full load. After the refrigerant is compressed and heated, part or all of it enters the spiral heat exchange coil of the phase change thermal storage unit through solenoid valve A; the high-temperature refrigerant in the heat exchange coil exchanges heat with the phase change material outside the coil. After absorbing heat, the phase change material gradually changes from solid to liquid, storing energy in the form of latent heat. After heat exchange, the temperature of the refrigerant drops to 35℃~40℃, and after passing through solenoid valve C and merging with the refrigerant returning from the terminal, it flows back to the air source heat pump to complete the cycle. The intelligent controller dynamically adjusts the refrigerant flow rate based on the temperature T_st of the phase change thermal storage unit: when T_st < 30℃, solenoid valve A is fully open, and all refrigerant enters the phase change thermal storage unit for heat storage; when 30℃ ≤ T_st < 35℃, the opening of solenoid valve A is adjusted to 50%-80%, with some refrigerant entering the phase change thermal storage unit and some entering the terminal to ensure basic heating. When T_st rises to 35℃, the intelligent controller issues a command to close solenoid valve A and switch to photovoltaic direct-drive heating mode.

[0040] 3. Implementation of Thermal Storage and Release Heating Mode: When the photovoltaic power sensor detects no sunlight or photovoltaic output P < 50% of the rated power of the air source heat pump, and the phase change thermal storage unit has residual heat, the intelligent controller determines that the current optimal mode is thermal storage and release heating mode, and then issues control commands: close solenoid valve A, select to start or stop the air source heat pump compressor according to the indoor heat load Q, and open solenoid valves B and C; the phase change material in the phase change thermal storage unit releases latent heat to heat the refrigerant in the heat exchange coil, and the terminal regulating valve adjusts the ratio of radiation and convection heating according to Q and T_in to ensure that the indoor temperature is stable at 20℃~24℃. When the phase change thermal storage unit temperature T_st drops to the lower limit of the temperature range, the intelligent controller issues a command; if there is still no photovoltaic output, it can switch to grid-assisted power supply mode to ensure heating continuity.

[0041] 4. Hybrid Complementary Mode Implementation: When the photovoltaic power sensor detects that the photovoltaic output P meets the requirements of 50% ≤ P < 100% of the rated power of the air source heat pump, and P < Q ≤ 1.1Q, and the phase change thermal storage unit has remaining heat storage, the intelligent controller determines that the current optimal mode is the hybrid complementary mode and immediately issues control commands: opening solenoid valves A, B, and C, the photovoltaic DC power drives the air source heat pump compressor to run at medium speed, and the phase change thermal storage unit releases energy; the refrigerant is divided into two paths, one path enters the terminal after being compressed and heated by the heat pump, and the other path merges into the main path after being heated by the phase change thermal storage unit, working together to deliver heat to the terminal. The intelligent controller dynamically adjusts the heat pump output and the opening of solenoid valve A based on the real-time monitored photovoltaic power P, indoor temperature T_in, and phase change thermal storage unit temperature T_st, optimizing the energy distribution ratio between the two. Through dynamic adjustment, it ensures that the total heat supply of the system meets the building's heat demand while maintaining a high COPmax.

[0042] Furthermore, this embodiment also includes a system protection mechanism: when the output voltage of the photovoltaic module exceeds 1.2 times the rated input voltage of the intelligent controller, the intelligent controller activates overvoltage protection, disconnects the photovoltaic module from the heat pump, and prevents equipment damage; when the operating current of the air source heat pump compressor exceeds 1.1 times the rated current, overcurrent protection is activated, reducing the compressor speed or stopping the compressor; when the temperature of the phase change thermal storage unit exceeds the upper temperature limit, over-temperature protection is activated, the connection pipeline between the heat pump and the phase change thermal storage unit is closed, and the heat dissipation device is turned on; when the indoor humidity exceeds the upper limit, the intelligent controller adjusts the speed of the terminal convection fan to increase by 5%-10%, accelerates indoor air circulation, reduces humidity, and improves thermal comfort.

[0043] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0044] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0045] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0046] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0047] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A photovoltaic direct-drive heat pump phase change thermal energy storage system, characterized in that, The system includes: photovoltaic modules, an intelligent controller, an air source heat pump, a phase change thermal storage unit, and a radiation-convection coupling terminal, wherein: The photovoltaic module is electrically connected to the input terminal of the intelligent controller, and the output terminal of the intelligent controller is electrically connected to the power supply terminal of the air source heat pump compressor. The air source heat pump is connected to the phase change thermal storage unit and the radiation-convection coupling terminal through pipelines. The intelligent controller is connected to the photovoltaic module, the air source heat pump, the phase change thermal storage unit and the radiation-convection coupling terminal for signal monitoring of the operating parameters of each component and control of the operating status.

2. The photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 1, characterized in that, The photovoltaic module is used to convert solar energy into direct current, and its output end is connected to the input end of the intelligent controller through a wire to provide renewable energy power to the system.

3. The photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 1, characterized in that, The intelligent controller is the core control unit with a built-in adaptive control algorithm. Its signal ports are connected to the photovoltaic power sensor, the temperature sensor of the phase change thermal storage unit, the indoor and outdoor temperature and humidity sensor, and the terminal load sensor, respectively. Its output terminal is electrically connected to the air source heat pump compressor, the solenoid valves of each pipeline, and the regulating device of the radiation-convection terminal to realize parameter monitoring and equipment control.

4. The photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 1, characterized in that, The air source heat pump includes a compressor, a four-way reversing valve, an outdoor heat exchanger, and an electronic expansion valve. The power supply of the compressor is connected to the output of the intelligent controller and is driven by photovoltaic DC power. The air source heat pump is connected to the phase change heat storage unit and the radiation-convection coupling terminal through pipelines. The pipelines are equipped with solenoid valves to switch the fluid flow direction and branch on / off.

5. The photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 1, characterized in that, The phase change thermal storage unit incorporates a high latent heat phase change material and a heat exchange coil. The two ends of the heat exchange coil are connected to the air source heat pump through pipelines, which is used to store surplus photovoltaic energy and release energy to supplement heating.

6. The photovoltaic direct-drive heat pump phase change thermal storage system according to claim 1, characterized in that, The integrated radiant plate and convection heat exchanger at the radiation-convection coupling end are connected to the air source heat pump and the phase change heat storage unit through pipelines, so as to dynamically adjust the ratio of radiant and convection heating according to the indoor load.

7. A control method for a photovoltaic direct-drive heat pump phase change thermal energy storage system, characterized in that, The method, applied to the photovoltaic direct-drive heat pump phase change thermal energy storage system as described in any one of claims 1 to 6, comprises: Step 1: Input parameters, including photovoltaic power, phase change thermal storage unit heat storage / release status, indoor temperature, outdoor temperature, indoor humidity, outdoor humidity, building heat load, and terminal operation parameters; Step 2: Establish a multi-parameter feedback model. The multi-parameter feedback model takes the parameters as input and outputs the optimal operating state parameters of the system through data fitting and algorithm optimization. The optimal operating state parameters include heat pump output, phase change unit heat storage / release rate, and terminal heating ratio. Step 3: Construct four operating modes and establish system energy efficiency models for each mode; Step 4: Calculate the maximum energy efficiency ratio (COPmax) of the system using an adaptive control algorithm. The maximum energy efficiency ratio is the maximum value among the calculation results of the four energy efficiency models. Step 5: Control the operation of each component according to the operating mode corresponding to the maximum energy efficiency ratio to achieve seamless mode switching.

8. The control method for a photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 7, characterized in that, The system energy efficiency model specifically includes: The energy efficiency model COPw for photovoltaic direct-drive heating mode reflects the ratio of system heating capacity to power consumption during photovoltaic direct drive. The COPs energy efficiency model of photovoltaic thermal storage mode reflects the ratio of system thermal storage efficiency to energy consumption when photovoltaic surplus is achieved. The energy efficiency model COPr for the thermal storage and release heating mode reflects the ratio of system heating efficiency to energy consumption when the phase change unit releases heat. The COPh energy efficiency model of the hybrid complementary mode reflects the overall energy efficiency ratio of the system when photovoltaic and phase change units operate in tandem.

9. The control method for a photovoltaic direct-drive heat pump phase change thermal energy storage system according to claim 8, characterized in that, The photovoltaic direct-drive heating mode is as follows: the photovoltaic power meets the load of the air source heat pump and the building's heat demand; the intelligent controller controls the branch of the phase change heat storage unit to close; the photovoltaic DC power directly drives the heat pump compressor; the heat pump compressor delivers heat to the radiation-convection coupling terminal; and the radiation-convection coupling terminal provides heat through radiation and convection in synergy. The photovoltaic thermal storage mode is as follows: the photovoltaic power is greater than the load of the air source heat pump and the instantaneous heat demand of the building; the intelligent controller controls the terminal branch to adjust as needed; the air source heat pump delivers heat to the phase change thermal storage unit; and the phase change material absorbs latent heat to store energy. The heat storage and release heating mode is as follows: when there is no sunshine or insufficient photovoltaic power, the phase change heat storage unit releases the stored latent heat, and the intelligent controller controls whether the air source heat pump is started according to the heat load demand. The heat is released into the room through the radiation-convection coupling terminal. The hybrid complementary mode is as follows: the photovoltaic power part meets the heat demand, the phase change thermal storage unit releases energy, and works in conjunction with the photovoltaic direct-drive heat pump to deliver heat to the terminal, dynamically adjusting the output ratio of the two.

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