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Bifacial solar system
Bifacial modules not only receive sunlight from the front side of the module, but also receive all kinds of reflected and scattered light from the ground, rooftops, clouds, and the atmosphere from the back side, generating power that is normally equal to or greater than that from the front side. It is possible to obtain the amount of power generated.
By utilizing both sides of the module, TSBM's TBM series can dramatically increase the footprint and power output per kWp.
The amount of power generated (kWh) increases by 10~20% compared to regular single-sided panels when installed on a regular slope.
Achieves a converted output of 348W per sheet with a 60-speed module*1
*1 = TB60M-290/348 H type Depends on the actual installation situation and environment.
High output bifacial photovoltaic panel
TB60M-290/348 H
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What is a bifacial solar cell?
As the name suggests, a bifacial solar cell is a solar panel in which both the front and back sides are light-receiving surfaces.
It can contribute to power generation by receiving light not only from the front side of the panel but also from the backside.
In the case of a typical inclined installation, the amount of power generated per panel can be increased by receiving reflected light from the ground and scattered light from the installation environment on the back side.
Structure of bifacial solar cell
Bifacial solar cells are manufactured from a single single-crystal silicon wafer.
Conventional single-sided light-receiving cells use the front side as the light-receiving surface, and the back side is mainly covered with aluminum paste and cannot receive light.
The back side of a bifacial photovoltaic cell has a structure similar to the diffusion layer formed on the front side, making it possible to receive light from the back side as well. Not only does the amount of power generation increase by receiving more light from the back side, but it also reduces the warping of the cells caused by the aluminum paste material, making it possible to make the wafer material thinner and reduce material costs.
General mono-facial cell
Bifacial solar cell
Structure of bifacial solar panel
To take advantage of the bifacial cell structure and allow light to enter from the back side, the bifacial solar panel has a structure in which the front side is sealed with tempered glass, and the back side is further sealed with tempered glass. (The back of some models uses a transparent back sheet)
Solar panels with a reinforced glass laminated structure have higher durability than conventional panels because they have less moisture infiltration through the resin back sheet during long-term outdoor use and are less susceptible to deterioration due to exposure to ultraviolet rays.
General mono-facial panel
Bifacial Panel
Power generation amount of bifacial solar cells
"Backside effect"
The effect of the back side of a bifacial solar cell on power generation was observed in a long-term experiment on the roof of a building with a typical flat roof structure under the supervision of Germany's Fraunhofer Institute.
"Backside effect" means the difference between the power generation amount of a typical single-sided panel and the power generation amount of a bifacial panel (kWh/kWp), which is the amount of power generated divided by the rated value of the front surface of the solar panel (kWh/kWp). It shows the difference.
The backside effect of the bifacial panel measured in Geilenkirchen, Germany, below was an annual average of +23%.
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Measurement site: Geilenkirchen, Germany
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Supervised and measured by Franhofer ISE, Germany
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Measured on the rooftop of an industrial building (flat roof/flat roof)
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A general single-sided panel and a double-sided panel are installed under the same conditions.
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Exam period: 2011-2012
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Panel tilt angle : 15°
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Direction: 145° (southeast)
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Albedo value (ground reflectance): 78%
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Panel installation height: FL ~ 30cm (to the lowest side of the module slope)
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Power conditioner : SMA Sunny boy 1.5kW x 2/string
Ideal for snowy areas
When it snows, conventional solar panels have the disadvantage that they stop generating electricity because their surfaces become covered with snow. On the other hand, double-sided panels can let in light from the open back side regardless of snowfall. When the sun begins to rise in the morning, the back side receives strong reflections from the snow surface and immediately starts generating electricity. As the panels begin to generate electricity by receiving light from the back, they generate heat due to the characteristics of crystalline solar cells, which causes the snow that has accumulated on the surface to begin to melt, making it easier to slide off. Therefore, bifacial panels can start receiving light and generating power on the surface earlier than regular solar cells, and can maintain a stable amount of power generation even in winter.
General mono-facial panel
Bifacial panel
We conducted an outdoor experiment to demonstrate what kind of solar cells are suitable for snowy areas.
In the experimental data below in Hirosaki City, Aomori Prefecture, from mid-December, when there was a lot of snowfall, the amount of power generated by bifacial panels and general single-sided panels increased, and in the end, it was recorded that the amount of power generated increased by approximately +20%. did.
Wh/Wp
Comparison of power generation during the snowfall period
November 2012 - February 2013 Hirosaki City, Aomori Prefecture
TB60M
Conventional mono-facial
Approximately 20%UP
Snowfall
FY2012 Hirosaki City Smart City Joint Research Project
Research conducted by Seiko Co., Ltd. (Aomori City, Aomori Prefecture)
Vertical installation of bifacial solar cells
Double-sided structure is also effective for vertical installation
Bifacial solar panels allow vertical installation by receiving daytime sunlight from both the front and back sides. In the case of east-west installation, you can receive light on the front side in the morning and continue receiving light using the back side in the afternoon. This dramatically improves the power generation capacity of vertical installations, which normally results in a large loss of power generation. By installing a bifacial solar panel vertically, the power generated is approximately 50% higher than when a general single-sided solar panel is installed vertically and roughly the same as when a general single-sided solar panel is tilted toward the south in the optimal direction. An equivalent amount of power generation can be obtained.
General mono-facial panel
Optimal slope angle facing south
Bifacial panel
vertical east-west direction
Wh/m2 day
time
Equivalent amount of power generated*
General mono-facial panel
South facing 30° x 40 sheets
The rooftop is full of panels
Equivalent amount of power generated*
10,600kWh/year
Wh/m2 day
time
Bifacial panel
Vertical installation x 40 sheets
Rooftop space can be effectively used for other purposes
10,200kWh/year
*Vertically installed bifacial solar panels can generate approximately 90 to 100% more power per year than standard single-sided panels installed facing south. (However, it varies depending on the panel model and installation latitude. Please contact us for details.)
Installation direction does not matter
Another advantage of vertically installed bifacial solar panels is that they are independent of the installation direction.
If a general single-sided solar panel is installed in a direction other than facing south, the amount of power it generates will decrease significantly. Vertical installation of bifacial solar panels makes it possible to obtain approximately the same amount of power generation throughout the year, even when installed in any direction (north, south, east, west, etc.) by making use of the front and back light-receiving surfaces.
It can also be used in installation environments where it is not always possible to face south.
West
South
east