A self-response phase change heat insulation wall body coupled with phase change energy storage and soil heat exchange and a control method thereof

Abstract

The application belongs to the technical field of building wall structure heat insulation, and relates to a self-response phase change heat insulation wall coupled with phase change energy storage and soil heat exchange and a control method thereof, comprising a phase change heat insulation unit, a monitoring unit, a control unit and a solar power supply unit. The application sends normal temperature water into a heat exchange coil buried in a soil constant temperature layer through a water pump, so that the water and the soil are fully heat exchanged in a wall type, the soil constant temperature layer is used for stably cooling the normal temperature water by using the relatively constant characteristics (low temperature) of the soil constant temperature layer all the year round, the cooled water is sent into a water-cooled wall heat exchange layer of the wall through an insulation water pipe under the power of the water pump, absorbs the heat transfer of the wall and the latent heat released by the solidification of the phase change material, and is returned to the underground soil layer to complete the heat transfer; the monitoring unit collects the inner surface temperature and water temperature data of the phase change heat insulation wall in real time, the control unit controls the start and stop of the water pump and the size of the water flow, and the solar power supply unit supplies power for the water pump, the monitoring unit and the control unit, so that the on-demand operation and intelligent energy-saving control can be realized, invalid energy consumption can be avoided, the heat transfer amount of the building wall can be effectively reduced, the heat insulation performance of the phase change wall can be improved, and the energy-saving and consumption-reducing purpose of the building wall can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of building wall structure thermal insulation technology, and relates to a self-responsive phase change thermal insulation wall coupled with phase change energy storage and soil heat exchange and its control method. Background Technology

[0002] Against the backdrop of the steady advancement of the "dual-carbon" strategy, energy conservation and carbon reduction in the building sector have become a crucial aspect of my country's green and low-carbon development. Heating, cooling, ventilation, and domestic hot water consumption during building operation are the main sources of building carbon emissions. Optimizing the performance of building envelopes and reducing building cooling / heating loads are key to achieving energy conservation and carbon reduction in buildings. As a vital carrier of heat exchange within the building envelope, the thermal performance of building exterior walls directly determines the quality of the indoor thermal environment and energy consumption. Optimizing the thermal insulation performance of exterior walls has significant engineering value for improving the living environment and reducing building energy consumption. Currently, building exterior walls mainly improve thermal resistance by adding insulation layers and optimizing wall structure. This passive insulation technology can only weaken heat transfer and cannot adapt to the periodic fluctuations in outdoor temperature, humidity, and solar radiation. Under summer conditions, the heat accumulated in ordinary walls during the day is easily released into the room at night, seriously affecting indoor thermal comfort and limiting the effectiveness of energy-saving control.

[0003] Phase change materials (PCMs) possess isothermal heat storage / release properties when they reach their phase change temperature, effectively suppressing wall temperature fluctuations, reducing building cooling / heating loads, and minimizing heat transfer, thus showing broad application prospects in building insulation. However, in areas with small diurnal temperature differences in summer and high nighttime ambient temperatures, the heat release and solidification of PCMs at night are insufficient, leading to a decrease in heat storage and temperature regulation performance the following day and causing heat accumulation problems, which significantly limits their engineering application effectiveness.

[0004] Soil possesses high thermal inertia and high heat capacity. The temperature of the constant-temperature layer soil fluctuates very little throughout the year, serving as a stable natural heat sink and source, providing constant heat exchange conditions. Low-temperature chilled water is prepared using heat exchange coils between water and the underground soil constant-temperature layer. Simultaneously, a water-cooled wall heat exchange layer is installed within the phase change wall. This not only reduces the heat transfer of the phase change wall but also accelerates the nighttime condensation and heat release of the phase change material layer. This solves the problems of insufficient condensation heat release and ineffective phase change cycle of traditional phase change walls, providing a new technical solution for the thermal insulation design of building exterior walls.

[0005] To address the above problems, this invention provides a self-responsive phase change insulation wall coupled with phase change energy storage and soil heat exchange, and its control method. Summary of the Invention

[0006] The purpose of this invention is to provide a self-responsive phase change thermal insulation wall coupled with phase change energy storage and soil heat exchange, and its control method, so as to reduce the heat transfer of the phase change wall in hot and humid summer climate and improve the thermal insulation performance of building exterior walls.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] A self-responsive phase change thermal insulation wall coupled with phase change energy storage and soil heat exchange includes a phase change thermal insulation unit, a monitoring unit, a control unit, and a solar photovoltaic power generation unit.

[0009] The phase change insulation unit includes a phase change insulation wall, a soil constant temperature layer heat exchange coil and a water pump. The main structure of the phase change insulation wall, from the outside to the inside, includes an outer plaster layer, an outer phase change layer, a water-cooled wall heat exchange layer, a brick layer, an inner phase change layer and an inner plaster layer.

[0010] The outer and inner phase change layers have a large latent heat storage and release capacity, which can effectively reduce the maximum heat flow through the wall and delay the time of the maximum heat flow, thus playing the role of "peak shaving and delay". The self-temperature regulation function of the phase change layer can transfer the heat through the wall in time and space, changing the pattern of heat transfer.

[0011] The water-cooled wall heat exchange layer utilizes the fluidity of water to carry away part of the sensible heat through convection heat exchange, while also effectively removing the latent heat during the solidification of the phase change layer, thereby improving the effectiveness of the phase change material's phase change cycle and enhancing the thermal insulation performance of the phase change wall.

[0012] The soil constant temperature layer heat exchange coil utilizes the characteristic that the local soil constant temperature layer has a low temperature and remains basically constant throughout the year. The heat exchange coil is used to achieve heat exchange between water and soil to produce cold water at a lower temperature.

[0013] The function of the water pump is to transport the cooled water, which has a lower temperature after heat exchange, to the water-cooled wall heat exchange layer in the phase change insulation wall.

[0014] The monitoring unit is used to detect in real time the inner surface temperature of the phase change insulation wall, the water temperature at the outlet of the heat exchange coil of the soil constant temperature layer, and the flow rate at the water pump outlet.

[0015] The control unit is connected to the monitoring unit and the water pump, respectively. It is used to receive the temperature data of the inner surface of the phase change insulation wall and the water temperature data at the outlet of the soil constant temperature layer heat exchange coil. It compares the detected temperature of the inner surface of the phase change insulation wall with the preset temperature and the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil with the preset water temperature. When the detected temperature of the inner surface of the phase change insulation wall is greater than the preset temperature, it controls the water pump to start; otherwise, it controls the water pump to stop. When the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil is greater than the preset water temperature, it controls the opening degree of the regulating valve to control the water flow rate, thereby adjusting the water temperature at the outlet of the soil constant temperature layer heat exchange coil.

[0016] The solar photovoltaic power generation unit includes a solar photovoltaic panel and a battery. The solar photovoltaic panel is installed on the roof surface of the building, and the battery is used to store the electrical energy converted by the solar photovoltaic panel.

[0017] The invention is further characterized by:

[0018] The monitoring unit includes a temperature sensor and a flow sensor.

[0019] The temperature sensor and flow sensor are electrically connected to the control unit.

[0020] The temperature sensor is used to detect the inner surface temperature of the phase change insulation wall and the outlet water temperature of the heat exchange coil in the soil constant temperature layer in real time, and the flow sensor is used to detect the cold water flow rate of the water-cooled wall heat exchange coil in real time.

[0021] The control unit includes a controller, which is electrically connected to a temperature sensor, a flow sensor, and a water pump.

[0022] The solar power supply unit includes a solar photovoltaic panel and a battery.

[0023] The solar photovoltaic panels are installed on the roof of the building and are electrically connected to the storage battery.

[0024] The storage battery is electrically connected to the water pump, monitoring unit, and control unit, respectively.

[0025] Both the soil constant temperature layer heat exchange coil and the heat exchange tubes in the water-cooled wall heat exchange layer are made of copper.

[0026] The design of a self-responsive phase change insulation wall coupling phase change energy storage and soil heat exchange also includes the following steps:

[0027] Obtain meteorological parameters and soil thermal properties of the area where the building is located, and determine the depth and temperature of the soil thermostatic layer based on the meteorological parameters and soil thermal properties.

[0028] The heat exchange coil of the soil constant temperature layer is buried in the soil constant temperature layer;

[0029] Prepare the outer phase change layer and the inner phase change layer;

[0030] The water-cooled wall heat exchange layer is placed between the outer phase change layer and the brick wall;

[0031] The monitoring unit detects temperature and flow rate in real time and feeds them back to the control unit.

[0032] The meteorological parameters include the annual average temperature of the area where the building is located, and the soil thermal property parameters include the annual average temperature of the soil surface layer in the area where the building is located.

[0033] The depth of the soil constant temperature layer needs to be determined based on meteorological parameters and soil thermal properties. First, the thermal conductivity of the soil in the area where the phase change insulation wall is located is determined by the formula for calculating the thermal conductivity of the soil. Then, the depth of the soil constant temperature layer is determined based on parameters such as the annual maximum daily average temperature, annual average temperature, annual atmospheric temperature amplitude, soil thermal conductivity, soil constant temperature layer temperature amplitude, soil thermal conductivity, and surface heat transfer coefficient between the earth's surface and the atmosphere in the area where the phase change insulation wall is located.

[0034] The temperature of the soil constant temperature layer is estimated using the annual average air temperature and the annual average temperature of the surface soil at the building location.

[0035] The solar photovoltaic panel converts solar energy into electrical energy and stores it in a battery.

[0036] The second objective of this invention is to provide a method for controlling the aforementioned phase change thermal insulation wall, characterized by comprising the following steps:

[0037] The system determines whether the environment of the phase change insulation wall is daytime or nighttime. If it is daytime, it enters daytime operation mode; if it is nighttime, it enters nighttime operation mode.

[0038] The daytime operation mode is as follows: When solar radiation and outdoor high temperature act together on the outside of the phase change insulation wall, heat enters the outer phase change layer through the outer plaster layer. When the temperature reaches the phase change temperature range of the outer phase change material, it begins to melt and absorb heat. Part of the heat transferred to the wall is stored in the outer phase change layer in the form of latent heat. After the phase change material changes from solid to liquid, the melting and heat absorption process ends. The heat continues to be transferred to the water-cooled wall heat exchange layer through the outer phase change layer. The cold water is heated, and the heat is further reduced. Then it continues to be transferred inward through the brick layer. Whether the inner phase change layer undergoes phase change and heat absorption at this time depends on the surface temperature of the inner phase change layer. When the surface temperature of the inner phase change layer is higher than its phase change temperature, the inner phase change layer begins to melt and absorb heat, storing heat in the form of latent heat. This results in a lower temperature reaching the inner surface of the phase change insulation wall, improving the thermal comfort of the building interior.

[0039] The nighttime operation mode is as follows: During nighttime heat dissipation, cold water flows through the water-cooled wall heat exchange layer, carrying away the heat dissipated by the solidification of the outer phase change layer. After absorbing heat, the water temperature rises and is sent back to the soil constant temperature layer heat exchange coil under the action of the water pump. The water indirectly exchanges heat with the soil through the soil constant temperature layer heat exchange coil. The cooled cold water continues to flow to the water-cooled wall heat exchange layer to absorb heat. This cycle is repeated to improve the cooling effect of the outer phase change layer.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] This invention organically combines phase change insulation wall technology based on phase change materials, water-cooled wall heat exchange, soil constant temperature layer heat exchange technology, and photovoltaic power generation system. During the daytime in summer when outdoor temperatures are high, the phase change insulation wall can store some heat energy during the day by relying on the high heat storage performance of the phase change layer and the convective heat exchange characteristics of the water-cooled wall. Some of this heat energy is then carried away by the cold water, reducing indoor air temperature fluctuations and peak temperatures, thus improving the thermal comfort of the building's interior environment. At nighttime in summer when outdoor temperatures are low, when the phase change layer condenses and releases heat, the water-cooled wall heat exchange layer can quickly remove the latent heat released by the phase change layer. This not only achieves rapid heat dissipation but also enables effective heat absorption / release cycles of the phase change material, solving the problem of incomplete heat dissipation of the phase change layer due to small diurnal temperature differences in hot-summer and cold-winter regions or hot-summer and warm-winter regions.

[0042] The phase change thermal insulation wall of the present invention effectively reduces the maximum heat flow through the wall, delays the time when the maximum heat flow occurs, reduces the amplitude of indoor temperature fluctuations, reduces the number of start-ups and shutdowns and the running time of air conditioning equipment, and saves energy and reduces consumption.

[0043] The solar photovoltaic power generation system of the present invention supplies power to the water pump, monitoring unit and control unit, enabling on-demand operation and intelligent energy-saving control, avoiding ineffective energy consumption, effectively reducing heat transfer in building walls, improving the thermal insulation performance of phase change walls, and achieving the goal of energy saving and consumption reduction in building walls. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0045] Figure 2 This is a schematic diagram illustrating the working principle of the present invention.

[0046] Figure 3 This is a schematic diagram of the phase change heat insulation wall in this invention.

[0047] Figure label: 1. Phase change insulation wall; 2. External plaster layer; 3. External phase change layer; 4. Water-cooled wall heat exchange layer; 5. Brick layer; 6. Internal phase change layer; 7. Internal plaster layer; 8. Solar photovoltaic panel; 9. Storage battery; 10. Water pump; 11. Water pipe; 12. Soil constant temperature layer heat exchange coil; 13. Controller; 14. Regulating valve; 15. Flow meter. Detailed Implementation

[0048] The technical solutions of the present invention will now be described clearly and in detail with reference to the accompanying drawings. In the description of the embodiments of the present invention, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of the present invention, "multiple" refers to two or more than two.

[0049] Example 1

[0050] like Figure 1 , Figure 2 As shown, this embodiment provides a structural feature of a self-responsive phase change thermal insulation wall that couples phase change energy storage with soil heat exchange, including a phase change thermal insulation unit, a monitoring unit, a control unit, and a solar photovoltaic power generation unit.

[0051] The phase change insulation unit includes a phase change insulation wall 1, a water pump 10, water pipes 11, and a soil constant temperature layer heat exchange coil 12; such as Figure 1 As shown, the structure of the phase change insulation wall 1 (from the outside to the inside) consists of an outer plaster layer 2, an outer phase change layer 3, a water-cooled wall heat exchange layer 4, a brick layer 5, an inner phase change layer 6, and an inner plaster layer 7.

[0052] The outer phase change layer 3 is set on the outside of the phase change heat insulation wall 1. Through phase change heat absorption / release, heat transfer from the outside to the inside can be reduced in summer.

[0053] The inner phase change layer 6 is set on the inner side of the phase change heat insulation wall 1. Through phase change heat absorption / release, it reduces the heat transfer from the inside to the outside in winter.

[0054] The water-cooled wall heat exchange layer 4 is set between the outer phase change layer 3 and the brick layer 5. It uses the cold water with a lower temperature inside the water-cooled wall to exchange heat with the phase change layer and uses the flow of water to carry away the heat. At the same time, it can also enhance the condensation heat dissipation of the outer phase change layer 3 at night.

[0055] The outlet of the water pump 10 is connected to the inlet of the water-cooled wall heat exchange layer, and the inlet of the water pump is connected to the outlet of the soil constant temperature layer heat exchange coil 12 through the water pipe 11.

[0056] The water pump 10 is powered by solar photovoltaic panels 8 and a storage battery 9.

[0057] The soil constant temperature layer heat exchange coil 12 is installed in the soil below the building where the phase change insulation wall 1 is located, and is located in the constant temperature layer soil. The inlet and outlet of the soil constant temperature layer heat exchange coil 12 are located in the upper part of the soil.

[0058] The monitoring unit is used to detect the inner surface temperature of the phase change insulation wall 1 and the water temperature at the outlet of the soil constant temperature heat exchange coil 12 in real time.

[0059] The control unit includes a controller 13, which is electrically connected to the monitoring unit, the water pump 10, and the regulating valve 14. It is used to receive the temperature data of the inner surface of the phase change insulation wall 1 and the temperature data of the outlet of the soil constant temperature layer heat exchange coil 12. The controller 13 compares the detected inner surface temperature of the phase change insulation wall 1 with the preset temperature and the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil 12 with the preset water temperature. When the detected inner surface temperature of the phase change insulation wall 1 is greater than the preset temperature, the controller 13 controls the water pump 10 to start, and the water pump 10 stops working otherwise. When the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil 12 is greater than the preset water temperature, the controller 13 controls the opening degree of the regulating valve 14 to adjust the water temperature at the outlet of the soil constant temperature layer heat exchange coil 12.

[0060] Example 2

[0061] This embodiment provides a design scheme for an external phase change layer 3 and an internal phase change layer 6 of a self-responsive phase change insulation wall coupling phase change energy storage and soil heat exchange, including the following:

[0062] The phase change temperature of the outer phase change layer 3 can be estimated by combining the thermal resistance method. Based on the summer temperature of the outer side of the wall, the peak shaving and delay function of the outer phase change layer, and the day and night melting and solidification cycle requirements of the phase change material, the phase change temperature range of the outer phase change layer 3 is determined to be about 30 to 34℃.

[0063] Furthermore, the selected phase change material is decanoic acid, which has a melting phase change temperature of 32.46℃, a latent heat of melting phase change of 160.81 J·g⁻¹, a solidification phase change temperature of 27.90℃, and a latent heat of solidification phase change of 172.06 J·g⁻¹.

[0064] Furthermore, decanoic acid is packaged using a hollow plate filling and sealing method.

[0065] The phase change temperature of the inner phase change layer 6 is determined based on the indoor air temperature, indoor side wall temperature, indoor heat gain, room operation mode, and existing literature. The phase change temperature range of the inner phase change layer 6 is approximately 18–22°C.

[0066] Furthermore, a binary phase change material was prepared by using lauric acid and decanoic acid in a ratio of 3:7. After 700 endothermic / exothermic cycles, its melting phase change temperature stabilized at 22.10 ℃, and its latent heat of melting phase change was 141.05 J·g⁻¹.

[0067] Furthermore, the binary phase change material of the inner phase change layer 6 is encapsulated using a hollow plate filling and sealing method.

[0068] Example 3

[0069] This embodiment provides a design scheme for the water-cooled wall heat exchange layer of a self-responsive phase change insulation wall that couples phase change energy storage with soil heat exchange, such as... Figure 3 As shown, the water-cooled wall heat exchange layer 4 is set between the outer phase change layer 3 and the brick wall 5. A horizontal distributor is arranged at the top and bottom of the wall. Several copper tubes with an inner diameter of 6mm are connected between the upper and lower distributors to serve as water-cooled walls. Cold water at about 19-20℃ from the soil constant temperature layer heat exchange coil 12 enters the water-cooled wall from bottom to top and carries away heat through the indirect heat exchange method. The spacing between the copper tubes of the water-cooled wall is 5mm.

[0070] Example 4

[0071] This embodiment provides a design scheme for a self-responsive phase change insulation wall monitoring unit that couples phase change energy storage with soil heat exchange. The monitoring unit includes a temperature sensor and a flow sensor.

[0072] The temperature sensor and flow sensor are electrically connected to the control unit.

[0073] Temperature sensors are used to detect the inner surface temperature of the phase change insulation wall 1 and the cold water temperature at the outlet of the heat exchange coil 12 in the soil constant temperature layer in real time.

[0074] Flow sensors are used to detect the flow rate at the pump outlet in real time;

[0075] Furthermore, the temperature sensor uses T-type thermocouple wires and is used in conjunction with a multi-channel temperature tester for data acquisition.

[0076] Furthermore, a liquid intelligent turbine flow meter is selected as the flow meter and installed on the outlet pipe of the water pump 10.

[0077] Furthermore, the controller 13 can control the opening degree of the regulating valve 14 installed on the outlet pipe of the water pump 10 to regulate the water flow. Temperature and flow data are collected independently by the temperature sensor and the flow sensor, respectively, so that the control unit can control the start and stop of the water pump and the opening degree of the valve, thereby realizing the intelligent operation of the whole system.

[0078] Example 5

[0079] This embodiment provides a control scheme for a self-response phase change thermal insulation wall control unit that couples phase change energy storage with soil heat exchange. The main body of the control unit is the controller 13, which is electrically connected to the temperature sensor, flow meter 15, regulating valve 14, and water pump 10.

[0080] The controller 13 compares the detected inner surface temperature of the phase change insulation wall 1, the outlet temperature of the water pump 10 with the preset temperature, and the detected flow rate with the preset flow rate. When the detected temperature is greater than the preset temperature, the controller controls the water pump 10 to start, and sends the water cooled by the soil constant temperature layer heat exchange coil 12 into the water-cooled wall heat exchange layer 4 through the water pipe 11 to absorb heat.

[0081] Among them, water pump 10 is a small DC water pump with a power of 84W, a flow rate of 2400L / H, a current of 3.5A, and adjustable speed. The water pump model can be adjusted appropriately according to the pipeline resistance.

[0082] Example 6

[0083] This embodiment provides a power supply method for electrical equipment related to a self-responsive phase change thermal insulation wall coupled with phase change energy storage and soil heat exchange. It mainly involves a solar power supply unit, including a solar photovoltaic panel 8 and a battery 9.

[0084] Furthermore, the solar photovoltaic panel 8 is used to be installed on the top of the building where the phase change insulation wall 1 is located.

[0085] Furthermore, the solar photovoltaic panel 8 uses monocrystalline silicon photovoltaic modules, which are composed of 8 groups of Poly 30 Wp 36 cells connected in series.

[0086] Furthermore, the solar photovoltaic panel 8 is installed with a fixed tilt angle for the light-receiving surface. When the tilt angle is 10° and the azimuth angle is 0°, the optimal conversion factor FT is 1.0.

[0087] Furthermore, the solar photovoltaic panel 8 is electrically connected to the battery 9.

[0088] The storage battery 9 is electrically connected to the water pump 10, the monitoring unit, and the control unit, respectively, to supply power to the water pump 10, the monitoring unit, and the control unit, so that the system can operate all day without being connected to the external power grid.

[0089] The storage battery 9 can work continuously for 24 hours under the highest load, and the storage battery 9 is preferably a lithium-ion battery.

[0090] Example 7

[0091] This embodiment provides a design scheme for a soil constant temperature layer heat exchange coil in a self-responsive phase change insulation wall that couples phase change energy storage with soil heat exchange:

[0092] Wherein, the soil constant temperature layer heat exchange coil 12 is made of copper tubes, and the arrangement form is a "loop" shape. The lower end of the water inlet pipe and the lower end of the water outlet pipe are respectively connected to two ends of the lowermost loop-shaped copper coil, the water outlet pipe is connected to the inlet of the water pump 10, and the water inlet pipe is connected to the water outlet pipe of the water-cooled wall heat exchange layer;

[0093] The flow velocity of water in the soil layer heat exchange coil 12 is 1.5m / s, the water flow rate of a single copper tube is 250L / min, the outer diameter of a single copper tube is 15mm, the wall thickness is 1mm, the spacing between adjacent loop-shaped copper tubes is 10cm, and the convective heat transfer coefficient between the water in the soil constant temperature layer heat exchange coil 12 and the inner surface of the copper tube is taken as 15.48W / (m 2 ·K).

[0094] Embodiment 8

[0095] This embodiment provides a method for determining the temperature and humidity of the soil constant temperature layer in a self-responsive phase-change heat insulation wall with coupled phase-change energy storage and soil heat exchange, and the specific method and embodiment are as follows:

[0096] Wherein, the meteorological parameters include the annual average temperature of the area where the building with the phase-change heat insulation wall 1 is located, the soil thermophysical parameters include the annual average temperature of the surface soil in the area where the building with the phase-change heat insulation wall 1 is located, and the local soil constant temperature layer temperature is estimated by integrating the local multi-year average temperature and the local annual average surface soil temperature.

[0097] The specific practice is as follows: select the climate data released by the local government department as a reference, obtain the annual average temperature of the region through statistical calculation, use the arithmetic mean of the surface soil temperatures in four seasons of the region to approximately estimate the annual average surface soil temperature, and integrate the multi-year average temperature and the annual average surface soil temperature of the region to estimate the local soil constant temperature layer temperature.

[0098] Wherein, when determining the depth of the soil constant temperature layer according to the meteorological parameters and soil thermophysical parameters, first determine the thermal diffusivity of the soil in the area where the phase-change heat insulation wall 1 is located according to the calculation formula of the soil thermal diffusivity, and then determine the depth of the soil constant temperature layer according to parameters such as the annual maximum daily average temperature, annual average temperature, annual amplitude of atmospheric temperature, soil thermal diffusivity, temperature amplitude of the soil constant temperature layer, soil thermal conductivity, and surface heat transfer coefficient between the ground surface and the atmosphere in the area where the phase-change heat insulation wall 1 is located.

[0099] Further, when determining the depth of the soil constant temperature layer according to the soil thermal diffusivity, annual average temperature and annual maximum temperature in the area where the phase-change heat insulation wall 1 is located, it is determined by the following formula:

[0100] ,

[0101] .

[0102] In the formula, φThis is a correction factor used to adjust for the impact of heat exchange between the Earth's surface and the atmosphere on soil temperature propagation. λ t is the soil thermal conductivity, in W / (m·K), and a is the soil thermal conductivity, in m. 2 / s, α 2 represents the surface heat transfer coefficient between the Earth's surface and the atmosphere, expressed in W / (m²). 2 ·K), τ 0 represents the annual cycle time, typically taken as 365 × 24 × 3600 s. H The depth of the soil constant temperature layer, T am The average annual temperature T amax The highest temperature of the year, T amax - T am The annual amplitude of atmospheric temperature is expressed in °C. ε The temperature amplitude of the soil isothermal layer is expressed in °C.

[0103] Definition of soil thermal conductivity:

[0104] ,

[0105] In the formula, a is the soil thermal conductivity coefficient, and m 2 / s; λ is the soil thermal conductivity, W / (m⋅K); ρ· c represents the soil volumetric heat capacity, J / (m³). 3 ⋅K).

[0106] Based on the basic characteristics and composition of the local soil layer, the thermal conductivity range of each component was calculated, and the arithmetic mean was taken as the thermal conductivity of the soil in that area.

[0107] Substitute local meteorological parameters and soil thermal conductivity into the above formula to determine the depth of the soil constant temperature layer.

[0108] Example 9

[0109] This invention also provides an operating mode for a self-responsive phase change insulation wall coupled with phase change energy storage and soil heat exchange, and its control method, comprising the following steps:

[0110] Among them, it is determined whether the environment of the phase change heat insulation wall 1 is daytime or nighttime. If it is daytime, it enters the daytime operation mode; if it is nighttime, it enters the nighttime operation mode.

[0111] The daytime operation mode is as follows: When solar radiation and outdoor high temperature act together on the outside of the phase change insulation wall 1, heat enters the outer phase change layer 3 through the outer plaster layer 2. When the temperature reaches the phase change temperature range of the outer phase change material, it begins to melt and absorb heat. Part of the heat transferred to the phase change insulation wall is stored in the outer phase change layer 3 in the form of latent heat. After the phase change material changes from solid to liquid, the melting and heat absorption process ends. The heat continues to be transferred to the water-cooled wall heat exchange layer 4 through the outer phase change layer 3. The cold water is heated, and the heat is further reduced. Then it continues to be transferred inward through the brick layer 5. Whether the inner phase change layer 6 undergoes phase change and heat absorption at this time depends on the temperature of the inner phase change layer surface 6. When the surface temperature of the inner phase change layer 6 is higher than its phase change temperature, the inner phase change layer 6 begins to melt and absorb heat, storing heat in the form of latent heat. This makes the temperature reaching the inner surface of the phase change insulation wall 1 lower, improving the thermal comfort of the building interior.

[0112] The nighttime operation mode is as follows: When the cooling is running at night, cold water flows through the water-cooled wall heat exchange layer 4, carrying away the heat dissipated by the solidification of the outer phase change layer 3. After absorbing heat, the water temperature rises and is sent back to the soil constant temperature layer heat exchange coil 12 under the action of the water pump 10. Through the soil constant temperature layer heat exchange coil 12, it indirectly exchanges heat with the soil. The cooled cold water continues to flow to the water-cooled wall heat exchange layer 4 to absorb heat. This cycle is repeated to improve the cooling effect of the outer phase change layer.

[0113] It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this invention are within the protection scope of this invention.

Claims

1. A self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange, characterized in that, It includes a phase change insulation unit, a monitoring unit, a control unit, and a solar photovoltaic power generation unit; The phase change insulation unit includes a phase change insulation wall (1), a water pump (10), a water pipe (11), a regulating valve (14), a flow meter (15), and a soil constant temperature layer heat exchange coil (12); the phase change insulation wall (1) includes, from the outside to the inside, an outer plaster layer (2), an outer phase change layer (3), a water-cooled wall heat exchange layer (4), a brick layer (5), an inner phase change layer (6), and an inner plaster layer (7); the outer phase change layer (3) is used to be installed on the outside of the phase change insulation wall (1), that is, on the inside of the outer plaster layer (2). By absorbing / releasing heat through phase change, the heat transfer from the outside to the inside in summer is reduced; the inner phase change layer (6) is used to be set on the inner side of the phase change heat insulation wall (1), that is, the inner side of the inner plaster layer (7), and by absorbing / releasing heat through phase change, the heat transfer from the inside to the outside in winter is reduced; the water-cooled wall heat exchange layer (4) is used to be set between the outer phase change layer (3) and the brick layer (5), and heat exchange is carried out with the phase change layer by means of the cold water with a lower temperature in the water-cooled wall, and the heat is carried away by the flow of water, thereby enhancing the condensation heat dissipation of the outer phase change layer at night; Furthermore, the inlet of the water pump (10) is connected to the outlet of the soil constant temperature layer heat exchange coil (12), and the outlet of the water pump (10) is connected to the inlet of the water-cooled wall tube of the water-cooled wall heat exchange layer (12). Furthermore, the power for the water pump (10) comes from the solar photovoltaic panel (8) and the storage battery (9). Furthermore, the soil constant temperature layer heat exchange coil (12) is used to be installed in the soil constant temperature layer below the building area where the phase change heat insulation wall (1) is located; Furthermore, the inlet and outlet of the soil constant temperature layer heat exchange coil (12) are located in the water pipe section perpendicular to the ground surface of the soil constant temperature layer; Furthermore, the regulating valve (14) is located on the pipeline at the outlet of the water pump (10); The monitoring unit includes a temperature sensor, a flow sensor, and a flow meter (15). The temperature sensor is used to detect the inner surface temperature of the phase change insulation wall (1) and the water temperature at the outlet of the soil constant temperature layer heat exchange coil (12) in real time. The flow sensor is used to detect the flow data of the flow meter (15) in real time. The flow meter (15) is used to measure the water flow. The control unit includes a controller (13) and a regulating valve (14). The controller (13) is used to control the start and stop of the water pump and control the opening degree of the regulating valve (14), thereby controlling the heat transfer of the wall and the flow rate and temperature of the cold water. The solar photovoltaic power generation unit includes a solar photovoltaic panel (8) and a battery (9). The solar photovoltaic panel (8) is laid on the roof surface of the building, and the battery (9) is used to store the electrical energy converted by the solar photovoltaic panel (8).

2. The self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 1, characterized in that, The monitoring unit includes a temperature sensor and a flow sensor, which are electrically connected to the control unit. The temperature sensor is used to detect the temperature in real time, and the flow sensor is used to detect the cold water flow rate in real time.

3. The self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 1, characterized in that, The controller (13) is electrically connected to the temperature sensor, flow sensor, water pump (10), and regulating valve (14) respectively, and is used to receive the inner surface temperature of the phase change insulation wall (1) and the water temperature at the outlet of the soil constant temperature layer heat exchange coil (12); the controller (13) compares the detected inner surface temperature of the phase change insulation wall (1) with the preset temperature and the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil (12) with the preset water temperature. When the detected inner surface temperature of the phase change insulation wall (1) is higher than the preset water temperature, the controller (13) will receive the water temperature at the outlet of the soil constant temperature layer heat exchange coil (12). At the preset temperature, the water pump (10) is started to send the cold water obtained from the heat exchange coil (12) of the soil constant temperature layer into the water-cooled wall heat exchange layer (4) of the phase change heat insulation wall (1). The heat of the phase change heat insulation wall (1) is carried away by the convection heat exchange of the cold water. Otherwise, the water pump (10) stops working. When the detected water temperature at the outlet of the soil constant temperature layer heat exchange coil (12) is greater than the preset water temperature, the controller (13) controls the opening degree of the regulating valve (14) to adjust the outlet water temperature of the soil constant temperature layer heat exchange coil (12).

4. The self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 1, characterized in that, The solar photovoltaic panel (8) is electrically connected to the battery (9), and the battery (9) is electrically connected to the water pump (10), the monitoring unit, and the control unit respectively, for supplying power to the water pump (10), the monitoring unit, and the control unit respectively.

5. The self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 1, characterized in that, The heat exchange coils of the soil constant temperature layer (12) and the heat exchange tubes of the water-cooled wall heat exchange layer (4) are both made of copper tubes.

6. A self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange, characterized in that, The design method for phase change thermal insulation walls as described in any one of claims 1 to 5 includes the following steps: Obtain meteorological parameters and soil thermal properties of the area where the building is located, and determine the temperature and depth of the soil constant temperature layer based on the meteorological parameters and soil thermal properties. The soil constant temperature layer heat exchange coil (12) is buried in the soil constant temperature layer; Prepare the outer phase change layer (3) and the inner phase change layer (6); The water-cooled wall heat exchange layer (4) is placed between the outer phase change layer (3) and the brick wall (5); The monitoring unit detects temperature and flow rate in real time and feeds them back to the control unit. The solar photovoltaic power generation unit provides power to the controller (13), water pump (10), and monitoring unit.

7. The design method for a self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 6, characterized in that, The depth of the soil constant temperature layer is determined based on meteorological parameters and soil thermal properties. First, the thermal conductivity of the soil in the area where the phase change insulation wall (1) is located is determined according to the calculation formula of the soil thermal conductivity. Then, the depth of the soil constant temperature layer is determined based on parameters such as the annual maximum daily average temperature, annual average temperature, annual atmospheric temperature amplitude, soil thermal conductivity, soil constant temperature layer temperature amplitude, soil thermal conductivity, and surface heat transfer coefficient between the surface and the atmosphere in the area where the phase change insulation wall (1) is located.

8. The control method for a self-responsive phase change insulation wall coupled with phase change energy storage and soil heat exchange according to claim 6, characterized in that, The phase change temperature range of the outer phase change layer (3) phase change material is about 30 to 34°C, and the phase change temperature range of the inner phase change layer (6) phase change material is about 18 to 22°C.

9. The design method for a self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 6, characterized in that, The water-cooled wall heat exchange layer (4) is set between the outer phase change layer (3) and the brick wall (5). A horizontal distributor is arranged at the top and bottom of the wall. Several copper tubes with an inner diameter of 6mm are connected between the upper and lower distributors to serve as water-cooled walls. Cold water from the soil constant temperature layer heat exchange coil (12) enters the water-cooled wall from bottom to top and carries away heat through the indirect heat exchange method. The spacing between the copper tubes of the water-cooled wall is 5mm.

10. The design method for a self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange according to claim 6, characterized in that, The heat exchange coil (12) in the soil constant temperature layer is made of copper tubes, arranged in a "loop" shape. The water inlet pipe and the water outlet pipe are respectively connected to the loop-shaped copper coil in the soil constant temperature layer, the water outlet pipe is connected to the inlet of the water pump (10), and the water inlet pipe is connected to the water outlet pipe of the water-cooled wall heat exchange layer (4). The flow velocity of water in the soil layer heat exchange coil (12) is 1.5m / s, the water flow rate of a single copper tube is 250L / min, the outer diameter of a single copper tube is 15mm, the wall thickness is 1mm, the spacing between adjacent loop-shaped copper tubes is 100mm, and the surface convective heat transfer coefficient of the heat exchange coil (12) in the soil constant temperature layer is taken as 15.48W / (m 2 ·K).

11. A control method for a self-responsive phase change thermal insulation wall coupling phase change energy storage and soil heat exchange as described in claims 1-10, characterized in that, Includes the following steps: Determine whether the environment of the phase change insulation wall (1) is daytime or nighttime. If it is daytime, enter the daytime operation mode; if it is nighttime, enter the nighttime operation mode. The daytime operation mode is as follows: When solar radiation and outdoor high temperature act together on the outside of the phase change insulation wall (1), heat enters the outer phase change layer (3) through the outer plaster layer (2). When the temperature reaches the phase change temperature range of the outer phase change material, it begins to melt and absorb heat. Part of the heat transferred to the wall is stored in the outer phase change layer (3) in the form of latent heat. After the phase change material changes from solid to liquid, the melting and heat absorption process ends. The heat continues to be transferred to the water-cooled wall heat exchange layer (4) through the outer phase change layer (3). The cold water is heated, and the heat is further reduced. Then it continues to be transferred inward through the brick layer (5). Whether the inner phase change layer (6) undergoes phase change and heat absorption at this time depends on the surface temperature of the inner phase change layer (6). When the surface temperature of the inner phase change layer (6) is higher than its phase change temperature, the inner phase change layer (6) begins to melt and absorb heat, storing heat in the form of latent heat, so that the temperature reaching the inner surface of the phase change insulation wall (1) is lower, thus improving the thermal comfort of the building interior. The nighttime operation mode is as follows: During nighttime heat dissipation operation, cold water flows through the water-cooled wall heat exchange layer (4), carrying away the heat emitted by the solidification of the outer phase change layer (3). After absorbing heat, the water temperature rises and is sent back to the soil constant temperature layer heat exchange coil (12) under the action of the water pump (10). The water indirectly exchanges heat with the soil through the soil constant temperature layer heat exchange coil (12). The cooled cold water continues to flow to the water-cooled wall heat exchange layer (4) to absorb heat. This cycle is repeated to improve the cooling effect of the outer phase change layer (3).

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