A heat pump mechanism and a distributed light-storage cold-heat combined supply system having the same

Abstract

The present application belongs to the technical field of energy storage, and particularly relates to a heat pump mechanism and a distributed light-storage-cooling-heat combined supply system with the heat pump mechanism. The interval between adjacent micro flow channels and the partition plate play the function of fins. The micro flow channel import end is divided into a first import and a second import with the same shape as the export end, the number of flow channels in the import area is increased, the heat exchange area per unit length is increased, and the overall heat exchange efficiency is improved. The export section effectively reduces the flow resistance by combining flow channels and increasing the flow channel spacing, which is conducive to the smoother discharge of gaseous refrigerant. The system adopts a hybrid energy storage scheme, in which the composite phase change material bears the basic cooling load, and the lithium battery is only used to adjust the peak load. Compared with a single energy storage mode, the overall cost of the energy storage system is significantly reduced. The composite energy storage structure can flexibly respond to load fluctuations and optimize the configuration of energy storage capacity, thereby improving the economic efficiency of the system while enhancing the adaptability and reliability of the system.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, and particularly relates to a heat pump mechanism and a distributed photovoltaic-storage-cooling-heating system having the heat pump mechanism. Background Technology

[0002] Against the backdrop of global energy transition and the "dual carbon" goal, the refrigeration industry faces an urgent need for low-carbon transformation. In existing technologies, evaporator flow channels are often designed with equal spacing and rectangular cross-sections. This results in a situation where, during refrigerant flow, the inlet section has low dryness and high heat exchange capacity but insufficient heat exchange area, while the outlet section has high dryness and significantly increased flow resistance, yet cannot effectively reduce pressure drop. This contradiction limits further improvements in evaporator heat exchange efficiency at safe charge levels, thus affecting energy storage performance.

[0003] Furthermore, to address the mismatch between energy supply and demand, existing systems typically employ a single energy storage solution. While lithium-ion battery energy storage offers fast response, its high cost significantly increases system investment and maintenance expenses, extending the payback period. Conversely, conventional phase change thermal storage materials, while lower in cost, suffer from technical bottlenecks such as poor thermal conductivity, susceptibility to phase separation, and short cycle life, resulting in slow storage / release rates, rapid efficiency degradation, and insufficient long-term system reliability. Summary of the Invention

[0004] The purpose of this invention is to provide a heat pump mechanism and a distributed photovoltaic-storage-cooling-heating system having the heat pump mechanism to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A heat pump mechanism includes an evaporator, the evaporator including a plurality of fins, the fins having a flow channel assembly for refrigerant to flow through, the flow channel assembly including a plurality of microchannels, the plurality of microchannels being arranged sequentially at intervals along the width direction of the fins;

[0007] The cross-section of the microchannel is trapezoidal, and the cross-sectional area of ​​the microchannel gradually decreases along the refrigerant flow direction. A baffle is provided at the inlet end of the microchannel, which divides the inlet end of the microchannel into a first inlet and a second inlet. The thickness of the baffle gradually decreases along the refrigerant flow direction.

[0008] Preferably, the upper bottom of the microchannel outlet end is 1mm, the lower bottom is 1.5mm, and the height is 2mm. The first inlet and the second inlet have the same dimensions as the microchannel outlet end.

[0009] A distributed photovoltaic-storage-cooling-heating combined supply system includes the aforementioned heat pump mechanism and a power supply mechanism. The power supply mechanism is electrically connected to a controller, and the controller is electrically connected to the heat pump mechanism. The heat generated by the heat pump mechanism is delivered to the thermal storage mechanism, and the cooling generated by the heat pump mechanism is delivered to the cold storage tank and the cold user.

[0010] The power supply mechanism includes photovoltaic power generation components and battery storage components, both of which are electrically connected to the controller.

[0011] The cold storage tank contains a cold storage agent, which includes a composite phase change material.

[0012] Preferably, the composite phase change material includes paraffin wax, expanded graphite, and carbon nanotubes.

[0013] Preferably, the paraffin wax has a mass fraction of 80%-85%, the expanded graphite has a mass fraction of 14%-19%, and the carbon nanotubes have a mass fraction of 1%-5%.

[0014] Preferably, the heat pump mechanism further includes a compressor, which is electrically connected to the controller. The compressor is connected to a condenser, which is heat exchanged with the heat storage mechanism. The condenser is connected to an expansion valve, which is connected to the evaporator. The evaporator is heat exchanged with the cold storage tank and the cold user, and the evaporator is connected to the compressor.

[0015] Preferably, the cold storage tank includes an outer shell, with a maintenance filling port and a refrigerant inlet at the top of the outer shell, a refrigerant outlet on the outer side wall of the outer shell located at the bottom of the outer shell, a heat insulation layer circumferentially arranged on the inner side wall of the outer shell, and a heat exchange structure and a cold storage structure arranged inside the outer shell.

[0016] Preferably, the cold storage structure includes a honeycomb structure, which is disposed inside the outer shell, the insulation layer is disposed outside the honeycomb structure, and the honeycomb structure is filled with the composite phase change material.

[0017] Preferably, the heat exchange structure includes a refrigerant coil disposed within the honeycomb structure, with the top end of the refrigerant coil extending out of the honeycomb structure and connected to the evaporator for heat exchange.

[0018] Preferably, the refrigerant coil is made of copper.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] In this invention, the spacing and baffles between adjacent microchannels function similarly to fins, dividing the inlet end of the microchannel into a first inlet and a second inlet with the same shape as the outlet end. This effectively increases the number of channels in the inlet region without increasing the complexity of the channel structure, thereby increasing the heat exchange area per unit length and improving the overall heat exchange efficiency. As the refrigerant flows from the inlet to the outlet and undergoes a liquid-to-gas phase transition, its heat transfer coefficient decreases, and its thermal conductivity weakens. Since the main heat transfer within the pipe is essentially complete at this point, the outlet section effectively reduces flow resistance by merging channels and increasing the channel spacing, facilitating smoother discharge of the gaseous refrigerant.

[0021] The system employs a hybrid energy storage solution, with composite phase change materials handling the basic cooling load and lithium batteries used only for peak load regulation. Compared to a single energy storage method, this significantly reduces the overall cost of the energy storage system. This hybrid energy storage structure can flexibly respond to load fluctuations and optimize energy storage capacity configuration, improving the system's operational economy while also enhancing its adaptability and reliability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0023] Figure 1 This is a schematic diagram of the distributed photovoltaic storage combined cooling and heating system of the present invention;

[0024] Figure 2 This is a schematic diagram of the flow channel assembly in this invention;

[0025] Figure 3 This is a schematic diagram of the cold storage tank in this invention;

[0026] The components include: 1. Outer shell; 2. Insulation layer; 3. Refrigerant coil; 4. Honeycomb structure; 5. Composite phase change material; 6. Refrigerant inlet; 7. Refrigerant outlet; 8. Inspection and filling port; and 9. Internal support frame. Detailed Implementation

[0027] 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.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Reference Figure 2 The present invention discloses a heat pump mechanism, including an evaporator, the evaporator including a plurality of fins, the fins being provided with a flow channel group for refrigerant to flow through, the flow channel group including a plurality of micro channels, the plurality of micro channels being arranged sequentially at intervals along the width direction of the fins;

[0030] The cross-section of the microchannel is set as a trapezoid, and the cross-sectional area of ​​the microchannel gradually decreases along the refrigerant flow direction. A baffle is provided at the inlet end of the microchannel, which divides the inlet end of the microchannel into a first inlet and a second inlet. The thickness of the baffle gradually decreases along the refrigerant flow direction.

[0031] The evaporator used here is an existing evaporator, which will not be described in detail here.

[0032] In this invention, the refrigerant is preferably R290.

[0033] The design was further optimized so that the upper bottom of the microchannel outlet is 1mm, the lower bottom is 1.5mm, and the height is 2mm. The first inlet and the second inlet have the same dimensions as the microchannel outlet.

[0034] The spacing between adjacent microchannels and the baffles act as fins. Under the action of the baffles, the inlet end of the microchannel is divided into a first inlet and a second inlet with the same shape as the outlet end of the microchannel, which indirectly increases the number of channels at the inlet, thereby increasing the heat exchange area per unit length and improving the heat exchange efficiency. Specifically, as the refrigerant gradually flows through the microchannel, it undergoes a phase change, evaporating from liquid to gas. At this time, the heat transfer coefficient of the refrigerant decreases and its thermal conductivity deteriorates. In addition, the heat transfer in the pipe is basically completed, so the channels are merged and the spacing between the channels at the outlet is increased, which reduces the flow resistance and allows the refrigerant to pass through more smoothly.

[0035] Reference Figure 1 , Figure 3 A distributed photovoltaic-storage-cooling-heating combined system includes a heat pump mechanism and a power supply mechanism. The power supply mechanism is electrically connected to a controller, and the controller is electrically connected to the heat pump mechanism. The heat generated by the heat pump mechanism is delivered to the thermal storage mechanism, and the cold generated by the heat pump mechanism is delivered to the cold storage tank and the cold user.

[0036] The power supply system includes photovoltaic power generation modules and battery storage modules, both of which are electrically connected to the controller;

[0037] The cold storage tank contains a cold storage agent, which includes a composite phase change material 5.

[0038] Photovoltaic power generation modules convert solar energy into electrical energy, while battery modules, preferably lithium batteries, store excess power. The controller intelligently switches the power supply mode based on photovoltaic power generation and load demand: direct drive when photovoltaic power is sufficient, and supplementary power from the batteries when insufficient. This reduces grid dependence, improves renewable energy utilization, and the hybrid energy storage architecture is economical and reliable.

[0039] The coolant is based on the composite phase change material 5. It stores and releases cold energy through the phase change process. The coolant flows through the coolant coil 3 in the coolant storage tank and exchanges heat with the composite phase change material 5 to achieve cold storage or cold release.

[0040] Photovoltaic power can directly drive or drive a heat pump after energy storage. The cooling capacity is supplied to users through the evaporator or stored in a cold storage tank, while the heat is recovered through the condenser to supply domestic hot water. This achieves optimized energy allocation, improves photovoltaic absorption rate and overall energy efficiency, and is suitable for scenarios such as cold chain logistics.

[0041] Further optimization of the scheme resulted in composite phase change material 5, which includes paraffin wax, expanded graphite, and carbon nanotubes.

[0042] Further optimization of the scheme involves using 80%-85% paraffin wax, 14%-19% expanded graphite, and 1%-5% carbon nanotubes.

[0043] This formulation balances heat storage capacity, thermal conductivity, and stability. Paraffin wax dominates the phase change process, expanded graphite forms a thermally conductive framework, and carbon nanotubes prevent material degradation.

[0044] Paraffin wax serves as the substrate to provide latent heat of phase change, expanded graphite enhances thermal conductivity, and carbon nanotubes stabilize performance. The composite phase change material 5 is prepared through a vacuum impregnation process to form a uniform composite material, optimize thermophysical properties, maintain a thermal conductivity of 4.8 W / (m·K) while suppressing phase separation, and ensure that the performance degradation is less than 5% after 1000 cycles, thus extending the service life.

[0045] Further optimization of the scheme includes a heat pump mechanism that also includes a compressor, which is electrically connected to the controller. The compressor is connected to a condenser, which is connected to the heat storage mechanism for heat exchange. The condenser is connected to an expansion valve, which is connected to the evaporator. The evaporator is connected to the cold storage tank and the cold user for heat exchange, and the evaporator is connected to the compressor.

[0046] The compressor drives R290 refrigerant, the condenser releases heat, which is used for hot water supply, the expansion valve throttles the flow, and the evaporator absorbs heat for cooling. The refrigerant undergoes a phase change during the cycle, transferring heat, and the controller regulates the operating status to achieve combined cooling and heating.

[0047] Further optimization of the scheme: the cold storage tank includes an outer shell 1, with a maintenance filling port 8 and a refrigerant inlet 6 at the top of the outer shell 1, a refrigerant outlet 7 on the outer side wall of the outer shell 1, the refrigerant outlet 7 being located at the bottom of the outer shell 1, a heat insulation layer 2 being provided circumferentially on the inner side wall of the outer shell 1, and a heat exchange structure and a cold storage structure being provided inside the outer shell 1.

[0048] The insulation layer 2 includes polyurethane foam to reduce heat loss. The outer shell 1 is a stainless steel pressure vessel. The maintenance injection port 8 is used for maintenance. The refrigerant inlet 6 and refrigerant outlet 7 realize the circulation of the composite phase change material 5. The refrigerant exchanges heat with the cold storage structure through the refrigerant coil 3 to store or release cold energy.

[0049] The structure of the cold storage tank ensures efficient cold storage, is reliable, and supports long-term cyclic use.

[0050] Further optimization of the scheme: the cold storage structure includes a honeycomb structure 4, which is set inside the outer shell 1, and the insulation layer 2 is set outside the honeycomb structure 4. The honeycomb structure 4 is filled with a composite phase change material 5.

[0051] The honeycomb structure 4 is composed of aluminum hexagonal units, filled with composite phase change material 5, forming a regular array. The honeycomb structure 4 increases the heat exchange area, promotes uniform heat exchange, improves the cold storage / release rate, and has structural stability, avoiding the influence of material volume changes.

[0052] The honeycomb structure 4 comprises multiple regular hexagonal tubes, with the sidewalls of adjacent regular hexagonal tubes connected, as shown in the diagram. Figure 3 As shown.

[0053] The scheme is further optimized. The heat exchange structure includes a refrigerant coil 3, which is set inside the honeycomb structure 4. The top of the refrigerant coil 3 extends out of the honeycomb structure 4 and is connected to the evaporator for heat exchange.

[0054] Further optimization of the design: the material of refrigerant coil 3 is copper.

[0055] The refrigerant coil 3 is a serpentine coil made of copper, which runs through the honeycomb structure 4 and connects to the evaporator. The refrigerant flows inside the refrigerant coil 3 and exchanges heat with the phase change material. Copper has good thermal conductivity, and the coil design optimizes heat exchange efficiency, achieving efficient cold air transfer.

[0056] In a further optimized design, an internal support frame 9 is provided inside the outer shell 1. The internal support frame 9 is located at the bottom of the outer shell 1 and is situated below the honeycomb structure 4.

[0057] The internal support frame 9 is a grid-like stainless steel structure that provides mechanical support.

[0058] One specific example: 1. Photovoltaic power generation stage: A photovoltaic power generation unit with 300-watt standard modules connected in parallel converts solar energy into electrical energy, which is then input into the controller.

[0059] 2. Intelligent scheduling stage: The controller integrates an LSTM neural network to predict photovoltaic output, combines multi-sensor load identification, and dynamically optimizes the operation mode through the NSGA-II algorithm.

[0060] 2.1 Photovoltaic direct drive priority mode: When photovoltaic power is sufficient, the power directly drives the heat pump mechanism. The refrigerant R290 absorbs heat in the evaporator and supplies the cooling capacity to users or exchanges heat with the composite phase change material 5 through the refrigerant coil 3 and stores it in the cold storage tank. The condenser exhausts heat and the heat is transferred to the 50-liter insulated water tank through the plate heat exchanger to produce domestic hot water.

[0061] 2.2 Hybrid Energy Storage Power Supply Mode: When photovoltaic power is insufficient, the controller switches to cold storage priority, the cold storage tank releases cold energy, and the lithium battery pack with a capacity of ≤1kWh provides supplementary power to cope with peak loads and ensure continuous system operation.

[0062] 2.3 Off-peak electricity-grid backup mode: Under extreme weather conditions, off-peak electricity storage and grid backup are activated. The parallel circuit between the storage tank and the evaporator is adjusted through a three-way solenoid valve to maintain reliability.

[0063] Safety monitoring phase: Distributed MQ-2 combustible gas sensors monitor R290 concentration in real time, and pressure-temperature dual-parameter interlock control ensures safety thresholds; in case of leakage, segmented suppression is triggered, such as compressor shutdown, exhaust start-up, and sealing valve activation.

[0064] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0065] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A distributed photovoltaic-storage-cooling-heating combined supply system, characterized in that, It includes a heat pump mechanism and a power supply mechanism. The power supply mechanism is electrically connected to a controller, and the controller is electrically connected to the heat pump mechanism. The heat generated by the heat pump mechanism is delivered to a heat storage mechanism, and the cold generated by the heat pump mechanism is delivered to a cold storage tank and a cold user. The power supply mechanism includes photovoltaic power generation components and battery storage components, both of which are electrically connected to the controller. The cold storage tank is provided with a cold storage agent, which includes a composite phase change material (5). The heat pump mechanism includes an evaporator, which includes a plurality of fins. The fins are provided with a flow channel group for refrigerant to flow through. The flow channel group includes a plurality of microchannels, which are arranged sequentially at intervals along the width direction of the fins. The cross-section of the microchannel is set as trapezoidal, and the cross-sectional area of ​​the microchannel gradually decreases along the refrigerant flow direction. A baffle is provided at the inlet end of the microchannel, which divides the inlet end of the microchannel into a first inlet and a second inlet. The thickness of the baffle gradually decreases along the refrigerant flow direction. The upper bottom of the microchannel outlet is 1mm, the lower bottom is 1.5mm, and the height is 2mm. The first inlet and the second inlet have the same dimensions as the microchannel outlet. The composite phase change material (5) includes paraffin wax, expanded graphite, and carbon nanotubes; The paraffin wax has a mass fraction of 80%-85%, the expanded graphite has a mass fraction of 14%-19%, and the carbon nanotubes have a mass fraction of 1%-5%.

2. The distributed photovoltaic-storage-cooling-heating combined supply system according to claim 1, characterized in that, The heat pump mechanism also includes a compressor, which is electrically connected to the controller. The compressor is connected to a condenser, which is heat exchanged with the heat storage mechanism. The condenser is connected to an expansion valve, which is connected to the evaporator. The evaporator is heat exchanged with the cold storage tank and the cold user, and the evaporator is connected to the compressor.

3. The distributed photovoltaic-storage-cooling-heating combined supply system according to claim 1, characterized in that, The cold storage tank includes an outer shell (1), with a maintenance filling port (8) and a refrigerant inlet (6) at the top of the outer shell (1), a refrigerant outlet (7) on the outer side wall of the outer shell (1), the refrigerant outlet (7) being located at the lower part of the outer shell (1), a heat insulation layer (2) being provided circumferentially on the inner side wall of the outer shell (1), and a heat exchange structure and a cold storage structure being provided inside the outer shell (1).

4. The distributed photovoltaic-storage-cooling-heating combined supply system according to claim 3, characterized in that, The cold storage structure includes a honeycomb structure (4), which is disposed inside the outer shell (1). The insulation layer (2) is disposed outside the honeycomb structure (4), and the honeycomb structure (4) is filled with the composite phase change material (5).

5. The distributed photovoltaic-storage-cooling-heating combined supply system according to claim 4, characterized in that, The heat exchange structure includes a refrigerant coil (3), which is disposed inside the honeycomb structure (4). The top end of the refrigerant coil (3) extends out of the honeycomb structure (4) and is connected to the evaporator for heat exchange.

6. The distributed photovoltaic-storage-cooling-heating combined supply system according to claim 5, characterized in that, The material of the refrigerant coil (3) is copper.

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