A building photovoltaic structure to improve fire safety in confined spaces

Abstract

The present invention discloses a building photovoltaic structure for improving fire safety in confined spaces, including a multi-stage baffle with a certain inclination angle arranged between a photovoltaic panel and a roof. The baffle is composed of a composite material containing a fireproof material, and there are channels between each stage for air circulation. On the one hand, by setting the baffle, the air flow resistance is increased, the flame length and direction are changed, and the fire threat to the building roof is reduced; on the other hand, when a fire occurs, the fire extinguishing material and the expansion coating inside the baffle can play a role in extinguishing and flame retardant. The present invention has practical value for improving the fire safety of building photovoltaics.

Description

Technical Field

[0001] The invention relates to the field of building photovoltaics and fire safety, and in particular to a building photovoltaic structure for improving fire safety in confined spaces. Background Art

[0002] With the popularization of the global low-carbon economy and the improvement of public environmental awareness, renewable energy such as solar energy has received more and more attention. As one of the important applications of solar energy, building photovoltaics is not only easy to install, but also can effectively improve the utilization rate of the building's outer space, and can also significantly reduce building energy consumption, generating huge economic benefits.

[0003] However, numerous fire accidents and investigation reports have shown that photovoltaic panels may increase the fire safety of building roofs and even endanger the safety of the entire building. Traditional building photovoltaics are mainly composed of upper photovoltaic panels and fixed brackets. After photovoltaics are installed, they form a hollow confined structure parallel to the roof. Studies have shown that the installation of building photovoltaics changes the flow field structure of the flame, which has a huge impact on the flame behavior. On the one hand, the direction of the flame changes from upward diffusion to diffusion along the parallel structure, which increases the flame attachment length on the roof; on the other hand, the confined space formed between the photovoltaic panels and the roof is prone to cause a chimney effect, which increases the flame length and further increases the heat transfer heat flow of the flame to the building roof, resulting in a decrease in the overall fire resistance of the building and a worse fire safety. In addition, when a house catches fire, the photovoltaic panels on the roof may also block the external fire-fighting water gun, causing the flame to spread rapidly in the confined space, seriously affecting the control of the flame and missing the best time to extinguish the fire. Summary of the invention

[0004] Based on the fire safety issues caused by traditional building photovoltaics, the present invention discloses a building photovoltaic structure for improving fire safety in confined spaces, which can reduce the adverse effects of building photovoltaics in the event of a fire and improve the fire safety of the building.

[0005] A building photovoltaic structure for improving fire safety in confined spaces, comprising a photovoltaic panel, a mounting bracket and a partition device. The photovoltaic panel is installed above the roof based on the mounting bracket. The partition device is arranged between the photovoltaic panel and the roof, and comprises a multi-stage baffle arranged on the edges of both sides of the photovoltaic panel and a partition net arranged on the lower edge of the photovoltaic panel. The height of the baffle increases step by step along the installation direction from the eaves to the roof.

[0006] Preferably, the lower edge of the baffle is connected to the roof, and the upper edge is not connected to the inner wall of the photovoltaic panel, leaving a gap for airflow to pass through; the outer edge of the baffle is flush with the outer edge of the photovoltaic panel.

[0007] Preferably, a plurality of the baffles are symmetrically distributed at equal intervals on the left and right sides of the photovoltaic panel along the center line of the photovoltaic panel, and have a certain inclination angle, and are overall distributed in a "V" shape with the bottom not connected, forming a V-shaped airflow channel that allows airflow to pass through.

[0008] Preferably, the inclination angle ranges from 30° to 45°, and the inclination angle is the angle between the baffle and the side edge of the photovoltaic panel, which is manifested as the baffle tilting toward the middle of the photovoltaic panel.

[0009] Preferably, the left and right baffles located on the same horizontal plane are defined as baffles of the same level. The length and width of each level of baffles are the same, and the height increases step by step from h / 3 to 4h / 5, where h is the building photovoltaic installation height.

[0010] Preferably, 3 to 5 levels of baffles are provided according to the length of the photovoltaic panel; and the baffles of each level located on the same side of the photovoltaic panel are distributed in parallel with equal intervals.

[0011] Preferably, a middle air channel is left between baffles of the same level, and according to the width w of the photovoltaic panel, the width of the middle air channel is w / 4~w / 2.

[0012] Preferably, the baffle comprises, from the outside to the inside, an outer protective structure layer, a fire extinguishing agent layer, an intumescent coating layer and a central supporting structure, wherein the outer protective structure layer is used to protect the baffle from corrosion and the like; after the outer protective structure is destroyed, the fire extinguishing agent layer can release flame retardants in a fire; and the intumescent coating layer can react to form an intumescent fire insulation layer while releasing the flame retardant.

[0013] Preferably, the materials of the baffle plates are wrapped layer by layer in an n-shape.

[0014] Beneficial Effects

[0015] The present invention discloses a building photovoltaic structure for improving fire safety in confined spaces. By setting a partition structure between the photovoltaic panel and the roof, the flame flow field structure is changed and the flow resistance is increased, thereby reducing the chimney effect and reducing oxygen transport, which greatly shortens the flame length. At the same time, the partition structure causes the flame to rise at the partition, effectively reducing the attachment length to the roof and reducing the heat flow to the roof. An air channel is left in the middle of the partition structure, which can improve the heat dissipation of the roof and improve the efficiency of photovoltaic power generation while improving fire safety.

[0016] Secondly, the multi-layer material structure inside the partition structure can also effectively provide fire safety protection. When the fire spreads, the outer protective layer provides basic heat flow and high temperature protection; when the temperature rises further, the fire extinguishing agent layer is released, and a large amount of dry powder, carbon dioxide, etc. are produced at high temperature to inhibit combustion; finally, the expansion coating expands rapidly at high temperature, which can not only prevent the spread of flames, but also provide thermal insulation protection for the building structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of a building photovoltaic structure for improving fire safety in confined spaces according to the present invention;

[0018] Figure 2 is a side view schematic diagram of a building photovoltaic structure for improving fire safety in confined spaces according to the present invention;

[0019] Figure 3 is a schematic cross-sectional view of the partition internal material of the building photovoltaic structure for improving the fire safety of confined space according to the present invention;

[0020] Figure 4 A comparison diagram of flame length of the building photovoltaic structure for improving fire safety in confined spaces of the present invention and the traditional building photovoltaic Y=0.45m symmetric surface;

[0021] Figure 5 A top view of the roof temperature of a photovoltaic structure for improving fire safety in confined spaces according to the present invention.

[0022] Reference numerals:

[0023] 1- Photovoltaic panel, 2- Roof, 3- Right baffle, 4- Left baffle, 5- Partition net. DETAILED DESCRIPTION

[0024] In order to better enable those skilled in the art to better understand the technical solution of the present invention, the implementation of the present invention is further described in detail below in conjunction with the accompanying drawings, and the content is intended to explain the present invention rather than to limit it. Example 1

[0025] like Figures 1 to 3 As shown, the present invention discloses a building photovoltaic structure for improving fire safety in confined spaces, including a photovoltaic panel 1, a mounting bracket, and a partition device. The photovoltaic panel 1 is installed above the roof based on the mounting bracket, and the partition device is arranged between the photovoltaic panel 1 and the roof 2, including baffles on both sides of the photovoltaic panel 1 and a partition net 5 on the lower side of the photovoltaic panel 1. There is a channel between the partition devices for air circulation. The lower entrance is a breathable partition net, which can prevent combustibles from entering the interior of the building photovoltaic, and the remaining partitions at all levels are solid structures.

[0026] like Figure 1 to Figure 2As shown, there are several baffles, the upper edge of which is not connected to the inner wall of the photovoltaic panel 1, and the lower edge is connected to the roof 2, leaving a gap for airflow to pass through. The baffles are symmetrically distributed on the left and right sides of the photovoltaic panel 1 along the center line of the photovoltaic panel 1, including the right baffle 3 and the left baffle 4. Several baffles located on the same side of the photovoltaic panel 1 are distributed in parallel at equal intervals to form a channel for airflow to pass through. At the same time, the outermost edge of the baffle is consistent with the outermost edge of the photovoltaic panel 1, which can more comprehensively cover the restricted space between the roof and the photovoltaic panel and reduce the combustible area in the event of a fire. The baffles on the left and right sides of the same horizontal line are defined as baffles of the same level, and the overall distribution is in a "V" shape with the bottom not connected.

[0027] The baffles on both sides of the photovoltaic panel 1 form a certain angle with the side edge of the photovoltaic panel 1. The angle is set to change the direction of the flame and reduce the chimney effect. In this embodiment, the angle range of 30°-45° is obtained based on engineering experience. The length and width of the baffles at each level are the same. In this embodiment, the length is 35~50cm and the width is 5~15cm. The heights of the baffles at each level are different. From the lower end to the upper end of the roof, the height of the multi-layer baffles increases successively, reaching the highest at the top of the roof, but it is always less than the distance h between the photovoltaic panel and the roof. In this embodiment, the baffles are determined to be 3-5 levels from bottom to top according to the size of the photovoltaic panel 1, and the building photovoltaic installation height is h. In order to weaken the airflow during fire, the baffles at each level are increased step by step from h / 3~4h / 5. The intervals between the baffles at each level are equal, and the intervals between the baffles at the same level are also equal, which can improve the problem of ventilation and heat dissipation. In this embodiment, the intervals between baffles of each level are 20-30 cm, and the intervals between baffles of the same level (middle air channels) are w / 4-w / 2, where w is the width of the photovoltaic panel.

[0028] To further provide effective fire safety protection, each layer of the baffle is composed of multiple materials, and is wrapped in an n-shaped pattern from the outside to the inside, with an outer protective structure layer, a fire extinguishing agent layer, an intumescent coating layer and a central support structure. The outer protective structure layer is used to protect the baffle from corrosion and other effects; after the outer protective structure is destroyed, the fire extinguishing agent layer can release flame retardants in the fire to achieve the purpose of fire extinguishing; the intumescent coating layer can react to form an intumescent fire insulation layer while the flame retardant is released to protect the roof structure of the building. The interior of each layer is composed of multiple materials, and is in an n-shaped pattern from the outside to the inside, which is the outer layer, fire retardant, and intumescent coating. Example 2

[0029] In order to better describe the technical gain of the present invention in improving the fire safety and heat dissipation performance of building photovoltaic structures, the fire safety and heat dissipation performance of the present invention are predicted and analyzed by using computational fluid dynamics and numerical combustion methods, as described in detail:

[0030] A commonly used building photovoltaic is 160cm long and 90cm wide. The inclination angle of the roof of the installation building is 23°. The installation height of the photovoltaic panel 1 from the roof 2 is 25cm. Its structure is also as follows Figure 1 According to the method for improving fire safety of the present invention, a partition structure is provided between the roof and the photovoltaic panel.

[0031] like Figure 1 As shown, the left baffle 4 and the right baffle 3 are both composed of four layers of baffles, and the baffles on the same side are parallel to each other and have an angle of 30° with the bottom edge of the roof. The length and width of each layer of baffles are the same, with a length of 40 cm and a width of 10 cm. The distance between adjacent baffles is 25 cm. The height of the baffles increases from the lower end to the upper end of the roof, and are 14, 16, 18, and 20 cm respectively.

[0032] like Figure 3 As shown, the internal structure of each layer of the baffle is in an n shape, which includes an outer protective structure layer, a fire extinguishing agent layer, an expansion coating layer and a central supporting structure from the outside to the inside. The fire extinguishing agent layer can release a large amount of dry powder, carbon dioxide, etc. at high temperature to suppress combustion.

[0033] In order to compare the effect of the building structure proposed in the present invention on improving fire safety, flame dynamics numerical simulation models were established based on two building structures, traditional photovoltaic buildings and the patent method. The flame source is propane, the left plane of the propane gas plane is set as the air inlet, the propane gas burner surface is set as the propane inlet, the inlet gauge pressure is 10Pa, the mass flow rate is 0.008kg / s, the ambient wind speed is 5.3m / s, and the gravity acceleration is set to 9.8m / s 2 The SST k-omega turbulence model is used to determine the reaction rate based on the mixing parameters of the reaction flow field, the second-order upwind scheme and the SIMPLE algorithm.

[0034] Figure 4 This is a comparison chart of the flame length of the Y=0.45m symmetric plane of the present invention and the traditional building photovoltaic. After the baffle is installed, the flame shape on both sides and the symmetric plane of the building photovoltaic is significantly different from that of the traditional building photovoltaic. Specifically, the flame is lifted at the partition, which reduces its attachment length to the roof, effectively reducing the negative impact of the chimney effect on the building, thereby improving the overall safety of the building; affected by the flow field change, the length and height of the flame inside the photovoltaic structure are significantly shortened, and the area of ​​the high-temperature area is reduced.

[0035] Figure 5This is a top view of the roof temperature of the present invention. It can be seen that the temperature distribution of the roof is significantly affected by the partition device. The temperature at the entrance is low, the temperature at the partition position drops sharply, and the temperature between adjacent partition devices is significantly reduced. The flame impact area is limited to the middle position of the photovoltaic. That is, the structure of the present invention not only reduces the temperature of the flame combustion, but also suppresses the range of the flame combustion. Considering the actual fire situation, the partition device can release flame-retardant gas, and the actual photovoltaic temperature can be better than the numerical calculation result.

[0036] In summary, the present invention provides a partition structure between the photovoltaic panel and the roof, thereby greatly shortening the flame length in the event of a fire, improving the heat dissipation of the roof, and thus improving the safety of the photovoltaic structure in the event of a fire.

[0037] The above is only part of the embodiments of the present invention. Although some terms are used in the present invention, the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the present invention. It is contrary to the spirit of the present invention to interpret them as any additional restrictions. The above is only to further illustrate the content of the present invention with examples for easier understanding, but it does not mean that the embodiments of the present invention are limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention.

Claims

1. A building photovoltaic structure for improving fire safety in confined spaces, comprising a photovoltaic panel, a mounting bracket and a partition device, wherein the photovoltaic panel is mounted on the roof based on the mounting bracket, and is characterized in that: The partition device is arranged between the photovoltaic panel and the roof, including multi-level baffles arranged on the edges of both sides of the photovoltaic panel and a partition net arranged on the lower edge of the photovoltaic panel. The height of the baffle increases step by step in the installation direction from the eaves to the roof. The lower edge of the baffle is connected to the roof, and the upper edge is not connected to the inner wall of the photovoltaic panel, leaving a gap for airflow to pass through; the outer edge of the baffle is flush with the outer edge of the photovoltaic panel; Several of the baffles are symmetrically distributed on the left and right sides of the photovoltaic panel at equal intervals along the center line of the photovoltaic panel, and have a certain inclination angle. The overall distribution is "V"-shaped with the bottom not connected, forming a V-shaped airflow channel that allows airflow to pass through.

2. The building photovoltaic structure for improving fire safety in confined spaces according to claim 1, characterized in that: The inclination angle ranges from 30° to 45°, and the inclination angle is the angle between the baffle and the side edge of the photovoltaic panel, which is manifested as the baffle tilting toward the middle of the photovoltaic panel.

3. The building photovoltaic structure for improving fire safety in confined spaces according to claim 2, characterized in that: The left and right baffles located on the same horizontal plane are defined as baffles of the same level. The length and width of each level of baffles are the same, and the height increases step by step from h / 3 to 4h / 5, where h is the photovoltaic installation height of the building.

4. The building photovoltaic structure for improving fire safety in confined spaces according to claim 3, characterized in that: Set 3 to 5 levels of baffles according to the length of the photovoltaic panel; the baffles of each level on the same side of the photovoltaic panel are distributed in parallel with equal intervals.

5. The building photovoltaic structure for improving fire safety in confined spaces according to claim 3, characterized in that: A middle air channel is left between baffles of the same level. According to the width w of the photovoltaic panel, the width of the middle air channel is w / 4 to w / 2.

6. The building photovoltaic structure for improving fire safety in confined spaces according to any one of claims 1 to 5, characterized in that: The baffle comprises, from outside to inside, an outer protective structure layer, a fire extinguishing agent layer, an intumescent coating layer and a central supporting structure, wherein the outer protective structure layer is used to protect the baffle; after the outer protective structure is destroyed, the fire extinguishing agent layer can release flame retardant in a fire; and the intumescent coating layer can react to form an intumescent fire insulation layer while releasing the flame retardant.

7. The building photovoltaic structure for improving fire safety in confined spaces according to claim 6, characterized in that: The materials of the baffle plates are wrapped layer by layer in an n-shape.

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