Solar energy driven ventilation cooling phase change thermal insulation wall and control method thereof

Abstract

This invention belongs to the field of phase change ventilation wall technology, and discloses a solar-driven ventilation and cooling phase change heat insulation wall and its control method. The phase change heat insulation wall includes a wall body, and an insulation layer and a PCM layer arranged sequentially from the inside to the outside on the wall body. An air gap is formed between the insulation layer and the PCM layer. The lower and upper ends of the air gap are respectively provided with an air inlet and an air outlet, and the air outlet is connected to a fan through a ventilation duct. A photovoltaic energy storage panel and a solar energy storage module are provided on one side of the wall body. This invention combines phase change wall, ventilation and solar energy storage technology. During the day, the air gap and PCM layer operate together to minimize the heat flow to the interior of the wall to achieve heat insulation. At night, the collected solar energy drives the fan to operate, so that the air layer can effectively remove the heat dissipated by the condensation of the PCM layer. While ensuring the effective and reliable operation of the phase change ventilation wall, the device achieves low power consumption operation.

Description

Technical Field

[0001] This invention relates to the fields of phase change insulation, ventilation technology, and photovoltaic application technology, and in particular to a solar-driven ventilation cooling phase change insulation wall and its control method. Background Technology

[0002] In recent years, building energy consumption has accounted for 22% of the nation's total energy consumption and 10% of its carbon emissions. Rapid population growth, comfort demands, and economic development have stimulated global energy demand. Excessive energy demand has led to energy shortages, increased carbon emissions, and other social and environmental problems. Meanwhile, building cooling energy consumption accounts for 16% of global energy consumption. Based on these data, building energy conservation is crucial for addressing the energy and environmental crisis. In hot-summer, cold-winter and hot-summer, warm-winter regions, where summer outdoor air temperatures and solar radiation are high and diurnal temperature variations are small, developing building envelopes with excellent thermal insulation properties is an important measure to improve building energy conservation.

[0003] Phase change material (PCM) is a material capable of changing its physical state within a certain temperature range. During melting, PCM absorbs and stores a large amount of latent heat of phase change; conversely, during solidification, it releases this stored heat into the environment. PCM absorbs or releases significant latent heat during phase change, but its own temperature remains almost constant, thus creating a wide temperature plateau. Therefore, applying PCM to building walls using specific techniques creates a phase change wall. This wall not only provides the functionality of a regular building wall but also stores or releases a large amount of latent heat of phase change at certain temperatures. This allows the phase change wall to effectively reduce the maximum heat flow through the wall, delay the occurrence of maximum heat flow, reduce indoor temperature fluctuations, decrease the frequency and duration of air conditioning start-ups and shutdowns, and save energy. Furthermore, PCM typically has a low thermal conductivity, maintaining high insulation performance both before and after the phase change. In summer, the temperature difference between day and night is small in hot-summer-cold-winter and hot-summer-warm-winter regions. The heat absorption and release process of PCM is a cyclical process. Incomplete heat release at night will inevitably affect the heat insulation effect of the phase change wall the next day. Therefore, solving the problem of effective heat dissipation of PCM at night is very important. The intervention of ventilation layer can effectively accelerate the heat dissipation of PCM layer in phase change wall at night. However, most of the current solutions using PCM involve placing PCM layer on the inner wall and combining it with active ventilation (directly driving ventilation equipment with electric power) to allow PCM layer to absorb and release heat quickly as needed. However, excessive wind speed will cause noise and reduce human comfort. Moreover, the energy consumption required for active ventilation is difficult to compare with the actual energy saving. Therefore, how to find a zero-power-consumption ventilated phase change wall structure has become a hot topic.

[0004] Therefore, the present invention provides a solar-driven ventilation cooling phase change thermal insulation wall and its control method. Summary of the Invention

[0005] To address the problem of ineffective heat dissipation of the PCM layer in traditional phase change wall applications during nighttime in regions with small diurnal temperature variations, this invention proposes a solar-driven ventilation-cooled phase change insulation wall, based on the characteristics of hot-summer-cold-winter and hot-summer-warm-winter regions with high summer solar radiation intensity. This provides a technical solution to improve the insulation performance of phase change walls. The design combines solar energy utilization, mechanical ventilation, and PCM insulation technologies, and enables low-power operation of the device.

[0006] The present invention provides a solar-driven, ventilated, and cooled phase change thermal insulation wall and its control method, which are achieved through the following technical solutions:

[0007] The first objective of this invention is to provide a solar-driven, ventilated, and cooled phase change thermal insulation wall, comprising a wall body and an insulation layer and a PCM layer arranged sequentially from the inside to the outside on the wall body.

[0008] There is a gap between the insulation layer and the PCM layer to form an air gap;

[0009] The lower end of the air interlayer is provided with an air inlet, which is connected to the outside through ventilation duct A to allow outside air to enter.

[0010] An air outlet is provided at the upper end of the air interlayer. The air outlet is connected to a fan through ventilation duct B. When the fan is turned on, outdoor air can be introduced into the air interlayer through the air inlet to achieve convection with the PCM layer. This allows the air to reduce the heat absorbed by the PCM layer before being discharged through the air outlet, thereby minimizing the transfer of heat to the interior of the wall and achieving a heat insulation effect.

[0011] One side of the wall body is provided with:

[0012] Photovoltaic energy storage panels are used to absorb solar radiation energy and convert it into electrical energy.

[0013] A solar energy storage module, electrically connected to the photovoltaic energy storage panel and the wind turbine, is used to receive and store the electrical energy transmitted by the photovoltaic energy storage panel and transmit the electrical energy to the wind turbine.

[0014] Furthermore, the PCM layer is made of a composite phase change material.

[0015] Furthermore, the composite phase change material is synthesized using heat-resistant and flame-retardant PVC as the macroscopic encapsulation container, expanded perlite with high thermal insulation performance as the adsorbent material, and a binary eutectic mixture of myristic acid and 52# paraffin in a mass ratio of 68:32 as the phase change material.

[0016] Furthermore, the melting point of the PCM layer is 39–41°C.

[0017] Furthermore, the thickness of the insulation layer is 30–70 mm.

[0018] Furthermore, the thickness of the air interlayer is 20–30 mm.

[0019] Furthermore, the angle between the photovoltaic energy storage panel and the wall body is 25° to 35°.

[0020] Furthermore, an electric air valve A is installed on the ventilation duct A, and the electric air valve A is electrically connected to the solar energy storage module.

[0021] Furthermore, an electric air valve B is installed on the ventilation duct B, and the electric air valve B is electrically connected to the solar energy storage module.

[0022] 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:

[0023] 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.

[0024] The daytime operation mode is as follows: the air outlet, air inlet, and fan are all closed to form a sealed air gap; the PCM layer mainly stores the heat energy from solar radiation during the day to reduce indoor temperature fluctuations and peak temperatures.

[0025] The nighttime operation mode is as follows: the solar energy storage module supplies power to the fan, which in turn keeps the air outlet, air inlet, and fan open, allowing outdoor air to be introduced into the air gap through the air inlet. The air then rapidly convects and exchanges heat with the PCM layer, expelling the heat absorbed by the PCM to the outside, thereby accelerating the solidification of the PCM layer and enabling the PCM in the phase change wall to effectively complete the heat absorption and release cycle. At the same time, it prevents the heat released by the PCM from being transferred into the room, improving the thermal comfort of indoor occupants and saving energy.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This invention organically combines phase change material (PCM)-based thermal insulation walls, interlayer ventilation technology, and a photovoltaic power generation system. During the summer, when outdoor temperatures are excessively high, the PCM insulation wall, with its high heat storage capacity, stores heat energy during the day, reducing indoor temperature fluctuations and peak temperatures, thus improving human comfort. At night, when the PCM layer condenses and releases heat, a silent fan can quickly cool the PCM layer, enabling effective heat absorption and release cycles. This solves the problem of incomplete heat dissipation from the PCM layer in hot-summer-cold-winter or hot-summer-warm-winter regions due to small diurnal temperature differences. Simultaneously, the photovoltaic power generation system provides electricity to the equipment during the day and, at night, uses the energy storage function of solar cells to drive the fan, effectively removing the heat released during PCM condensation. The entire system operates with zero power consumption.

[0028] This invention links phase change wall with solar energy storage technology. During the day, the combined operation of the ventilation layer and the PCM layer minimizes heat transfer to the interior of the wall, achieving a heat insulation effect. At night, the excess electricity stored in the solar cells drives the fan to operate, effectively carrying away the heat released by the condensation of the PCM through the air layer, ensuring the effective and reliable operation of the phase change ventilation wall, while achieving low power consumption operation of the device.

[0029] 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.

[0030] The phase change thermal insulation wall of the present invention adopts outdoor cavity ventilation. Since it is independent of the indoor environment, the noise is low and will not affect the indoor environment, and will not bring a noticeable draft to the people inside. Attached Figure Description

[0031] Figure 1 This is a cross-sectional side view of the solar-driven phase change thermal insulation wall of the present invention;

[0032] Figure 2 This is a schematic diagram of the daytime operation mode of the phase change thermal insulation wall of the present invention;

[0033] Figure 3 This is a schematic diagram of the nighttime operation mode of the phase change thermal insulation wall of the present invention. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Example 1

[0036] Please see Figure 1This embodiment provides a solar-driven, ventilated, and cooled phase change thermal insulation wall, including a wall body 1, and an insulation layer 2 and a PCM layer 4 arranged sequentially from the inside to the outside on the wall body 1. 。

[0037] There is a gap between the insulation layer 2 and the PCM layer 4 to form an air interlayer 3; the lower end of the air interlayer 3 is provided with an air inlet 6, which is connected to the outside through a ventilation duct A to allow outside air to enter; the upper end of the air interlayer 3 is provided with an air outlet 5, which is connected to a fan 8 through a ventilation duct B.

[0038] A photovoltaic energy storage panel 10 and a solar energy storage module 9 are installed on one side of the wall body 1. The photovoltaic energy storage panel 10 is used to absorb solar radiation energy and convert it into electrical energy; the solar energy storage module 9 is electrically connected to the photovoltaic energy storage panel 10 and the wind turbine 8, and is used to receive and store the electrical energy transmitted by the photovoltaic energy storage panel 10 and transmit the electrical energy to the wind turbine 8.

[0039] In this embodiment, in order to facilitate the adjustment of the air flow rate and the closed or open state of the air interlayer 3 according to actual needs, an electric air valve A electrically connected to the solar energy storage module 9 is provided on the ventilation duct A, and an electric air valve B electrically connected to the solar energy storage module 9 is provided on the ventilation duct B.

[0040] The photovoltaic energy storage panel 10 can quickly achieve photoelectric conversion during periods of strong daytime radiation.

[0041] The solar energy storage module 9 can work continuously for 24 hours under the highest load, and the wind speed is adjustable.

[0042] Example 2

[0043] This embodiment provides a solar-driven, ventilated, and cooled phase change thermal insulation wall. In addition to embodiment 1, this embodiment uses a composite phase change material with a melting point of 39-41°C to fill and form the PCM layer 4 in order to improve the thermal insulation effect of the PCM layer 4.

[0044] Furthermore, the composite phase change material in this embodiment uses heat-resistant and flame-retardant PVC as the macroscopic encapsulation container, expanded perlite with high thermal insulation performance as the adsorbent, and a binary eutectic mixture of myristic acid and 52# paraffin wax in a mass ratio of 68:32 as the phase change material. The specific synthesis method is as follows:

[0045] First, myristic acid and #52 paraffin are mixed at a mass ratio of 68:32, heated to 65°C and stirred for 30 minutes to obtain a binary eutectic mixture. Second, the obtained binary eutectic mixture is mixed with expanded perlite at a mass ratio of 65:35 and treated in a vacuum drying oven at 80°C and -0.08 MPa for 6 hours, with stirring for 5 minutes every 2 hours to obtain a composite phase change material. Finally, the obtained composite phase change material is filled into a PVC container to obtain a phase change plate used as a phase change layer.

[0046] Example 3

[0047] This embodiment provides a solar-driven, ventilated, and cooled phase change thermal insulation wall. Based on embodiment 1, in order to improve the thermal insulation effect of the insulation layer 2, the insulation layer 2 is made of polyurethane material and has a thickness of 30-70mm.

[0048] Example 4

[0049] This embodiment provides a solar-driven, ventilated, and cooled phase change thermal insulation wall. Based on embodiment 1, this embodiment avoids overheating that could affect energy efficiency. In this embodiment, the angle between the photovoltaic energy storage panel 10 and the wall body 1 is 25° to 35°.

[0050] Example 5

[0051] This embodiment provides a control method for a phase change thermal insulation wall in any one of Embodiments 1-4. When the environment of the phase change thermal insulation wall is during the daytime, the daytime operation mode is selected for control, specifically including the following steps:

[0052] The air outlet 5, air inlet 6, and fan 8 are all closed to form a sealed air gap 3; the heat energy from daytime solar radiation is mainly stored through the PCM layer 4 to reduce indoor temperature fluctuations and peak temperatures.

[0053] During the summer daytime, the wall temperature is generally higher than the melting phase transition temperature of PCM. PCM absorbs heat during melting, preventing heat from entering the room. This design operates in the following daytime mode: Figure 2 As shown:

[0054] The photovoltaic energy storage panel 10 absorbs solar radiation and converts it into electrical energy to charge the solar energy storage module 9.

[0055] Air outlet 5, air inlet 6, electric air valve 7, and fan 8 are all in the closed state.

[0056] The beneficial effects of this mode are as follows: When the outdoor temperature is too high during the day in summer, the phase change insulation wall can store heat energy during the day due to its high heat storage performance, reducing indoor temperature fluctuations and peak temperatures, and improving human comfort. At this time, closing the air outlet 5, air inlet 6, air valve 7, and fan 8 allows the air interlayer 3 to form a closed cavity, making it difficult for air to flow within the cavity, and heat transfer mainly occurs through conduction. Simultaneously, thanks to the thermal conductivity of air, it can form a double insulation layer that works in coordination with the PCM layer 4, thereby significantly reducing the amount of heat gained indoors during the day.

[0057] Example 6

[0058] This embodiment provides a control method for a phase change thermal insulation wall in any one of Embodiments 1-4. When the environment of the phase change thermal insulation wall is at night, a nighttime operation mode is selected for control, specifically including the following steps:

[0059] Power is supplied to the fan 8 via the solar energy storage module 9, which in turn keeps the air outlet 5, air inlet 6, and fan 8 all open. This allows outdoor air to be drawn into the air interlayer 3 through the air inlet 6. The air then rapidly convects and exchanges heat with the PCM layer 4, expelling the heat absorbed by the PCM to the outside, thereby accelerating the solidification of the PCM layer 4 and enabling the PCM in the phase change wall to effectively complete the heat absorption and release cycle. At the same time, it prevents the heat released by the PCM from being transferred to the indoor environment, improving the thermal comfort of indoor occupants and saving energy.

[0060] During summer nights, when the wall temperature typically cannot fall below the solidification phase transition temperature of the PCM, the solar energy storage module 9 activates the fan 8, causing rapid airflow within the interlayer to cool the PCM layer 4. This design operates in the following nighttime mode: Figure 3 As shown:

[0061] The photovoltaic energy storage panel 10 is in the off state.

[0062] The solar energy storage module 9 is in the on state and supplies power to the wind turbine 8.

[0063] Air outlet 5, air inlet 6, air valve 7, and fan 8 are all in the open state.

[0064] The beneficial effects of this mode are as follows: During summer nights, the heat release process of the phase change material (PCM) layer in the phase change wall is also crucial. Incomplete heat release at night will inevitably affect the thermal insulation effect of the phase change wall the next day. This system uses an intelligent control system to open the air outlet 5, air inlet 6, air valve 7, and fan 8 to introduce outdoor air into the air interlayer 3. Through rapid convection heat exchange with the PCM layer 4, the heat absorbed by the PCM is discharged outdoors, thereby accelerating the solidification of the PCM layer 4 and enabling the PCM in the phase change wall to effectively complete the heat absorption and release cycle. At the same time, it avoids the heat released by the PCM from being transferred to the room, improving the thermal comfort of indoor occupants and saving energy.

[0065] The above description, using text and accompanying drawings, only illustrates the structure of some specific embodiments of typical examples of the present invention, and the implementation of the present invention is not limited thereto. Obviously, the above embodiments are merely 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.

Claims

1. A solar powered, ventilated, phase change thermal mass wall, characterized in that, The wall body (1) comprises a heat preservation layer (2) and a PCM layer (4) arranged in sequence from inside to outside on the wall body (1); the thickness of the heat preservation layer (2) is 30-70 mm; the thickness of the PCM layer (4) is 20-30 mm; the melting point of the PCM layer (4) is 39-41℃; the PCM layer (4) is made of composite phase change material; An air interlayer (3) is formed between the heat preservation layer (2) and the PCM layer (4); the thickness of the air interlayer (3) is 20-30 mm; An air outlet (5) is arranged at the upper end of the air interlayer (3), and a fan (8) is connected to the air outlet (5) through a ventilation pipeline; An air inlet (6) is arranged at the lower end of the air interlayer (3) for communication with the outside to allow outside air to enter; The wall body (1) is provided with: A photovoltaic energy storage panel (10) for absorbing solar radiation and converting it into electrical energy; the angle between the photovoltaic energy storage panel (10) and the wall body (1) is 25°-35°; A solar energy storage module (9) is electrically connected with the photovoltaic energy storage panel (10) and the fan (8) for receiving and storing the electrical energy transmitted by the photovoltaic energy storage panel (10) and transmitting the electrical energy to the fan (8).

2. The solar powered, ventilated, phase change insulated wall of claim 1, wherein, The composite phase change material uses heat-resistant and flame-retardant material PVC as a macroscopic packaging container, uses expanded perlite with high heat insulation performance as an adsorbent material, and uses a binary eutectic mixture of myristic acid:52# paraffin with a mass ratio of 68:32 as a phase change material.

3. The phase change thermal barrier wall of claim 1, wherein, An electric air valve (7) is arranged on the ventilation pipeline, and the electric air valve (7) is electrically connected with the solar energy storage module (9).

4. A method of controlling the phase change thermal insulation wall according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: Determine whether the environment of the phase change heat insulation wall is daytime or nighttime, if it is daytime, enter daytime operation mode, if it is nighttime, enter nighttime operation mode; The daytime operation mode is that the air outlet (5), air inlet (6) and fan (8) are all in a closed state to form a closed state of the air interlayer (3); mainly store the heat energy of daytime solar radiation through the PCM layer (4) to reduce indoor air temperature fluctuation and peak temperature; The nighttime operation mode is that the fan (8) is powered by the solar energy storage module (9), and then the air outlet (5), air inlet (6) and fan (8) are all in an open state through the fan (8), so that outdoor air is introduced into the air interlayer (3) through the air inlet (6), and the heat absorbed by the PCM is discharged to the outside through the air interlayer (3).

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