Let everyone know what is Building integrated Photovoltaic(BIPV)
Photovoltaic power stations are divided into the following two categories: centralized, industrial and commercial and household distributed photovoltaic，Among them, industrial and commercial, household distributed photovoltaic is divided into two types combined with the building and not combined with the building。
BAPV and BIPV are both a type of building photovoltaic:
1.BAPV, photovoltaic installation type, Building attached photovoltaics, photovoltaic system attached on the surface buildings.
2. BIPV, Building integrated Photovoltaic (PV) , system becomes a direct Building material.
What is BAPV？
BAPV is a simple and architecturally integrated model, applicable to the renovation of an existing roof. Additional steel structure supports or rails are installed directly on the roof of the building, and photovoltaic panels are fixed to generate electricity. Most rooftop solar projects on existing houses take this approach.
BAPV is the easier way to implement it, but it suffers from several problems:
1. Load: the original roof load does not meet the requirements for the secondary installation of photovoltaic panels, and the roof needs to be reinforced again. However, it is difficult for some old houses to
2.solar PV panel service life: the inverter and junction box used with the module will be exposed to the outdoors, easy to be damaged, reducing the actual service life of BAPV. strengthen.
3.waterproof :BAPV exists will destroy the original waterproof layer of the roof may, built after the need to repair, bring drainage hidden trouble to house.
What is BIPV？
BIPV is a photovoltaic system that becomes a direct building material. At present, a series of photovoltaic building materials such as photovoltaic roof, photovoltaic glass, photovoltaic curtain wall and photovoltaic tile have been developed.
BIPV can be divided into building material type and component type according to the form of expression：
“Building material type” is a relatively ideal form, which needs to be highly customized, and has high strength requirements and high cost. “Building materials” integration is more perfect, directly integrate photovoltaic cells into building materials, from the appearance and traditional building materials little difference.
Among them, Tesla photovoltaic tiles are “building materials”. According to Musk’s first customer feedback, it’s suitable for “financially insensitive” people, so you can imagine how expensive it is.
“Component type” tends to be standardized products, mainly used in the roof of industrial and commercial workshop, rainproof shed and other large roof, large building exterior curtain wall, this combination of photovoltaic modules and building components into an integral component, the appearance is easier to distinguish from traditional building materials. At present, the mainstream of the market is mainly photovoltaic roof, photovoltaic curtain wall, photovoltaic sun visor, on the one hand, it can maintain the power generation efficiency of the module to the highest degree and maximize the effective power generation area of the battery.
Now photovoltaic module manufacturing companies have also introduced transparent and colorful photovoltaic curtain walls, from the architectural aesthetic design, to provide house builders with more options for design styles.
Photovoltaic curtain wall has the dual attributes of photovoltaic and building. In the design, the building function requirements are higher than the requirements of photovoltaic power generation, and sometimes the photovoltaic attributes will be sacrificed, such as higher power generation efficiency, better lighting Angle, and larger power generation. Because of the design, construction and installation of buildings at the same time, the cost is higher. In addition to the power generation function, the building function requirements should be met: external maintenance, transparency, mechanics, aesthetics, safety, etc
BIPV can be divided into crystalline silicon type and thin film type by material：
Crystalline silicon is the most familiar material. Crystalline silicon BIPV, high conversion efficiency, single crystal up to 25%. Crystalline silicon cells are opaque, and crystalline silicon components are mainly used in opaque construction projects. Of course, the double-sided glass of crystal silicon photovoltaic curtain wall can also meet certain requirements of light transmission.
Thin-film BIPV is mainly composed of cadmium telluride (CdTe) cells, copper indium gallium selenium (CIGS) cells and perovskite solar cells. The unique advantages of thin film: better low light, adjustable transparency, and better temperature coefficient ensure that it can be maintained in extreme conditions such as high temperature and low light. However, it is not as efficient as crystalline silicon type.
The development of BIPV technology
The development process of BIPV technology can be summarized with the content of this paper.
First generation: The facade of the building is similar to BAPV by mounting photovoltaic arrays with some additional supports and fixtures. The main stream is crystalline silicon BIPV.
The second generation: thin film battery, photovoltaic module and building materials together, beautiful appearance. Low reliability and high maintenance cost.
The third generation: full integration of photovoltaic system, building materials and power conversion equipment. Because of the cost and other issues, it is necessary to develop a new generation of technology and materials.
For users with photovoltaic power generation needs, the following schemes can be proposed: for large public buildings without lighting demand such as shopping malls, crystal silicon curtain wall scheme can be selected. For offices and other buildings with lighting requirements, thin-film batteries can be selected, double-sided glass can also be selected, and crystal silicon components with certain transmittance.