Albedo of a PV cell
As we all know that the solar panels use the sun’s energy to produce usable electricity which is measured in percentage and called as solar panel efficiency. Do you know how much percentage of incident solar radiation is converted into usable electricity? It isn’t a great number, the most efficient solar panel converts around 23% of solar radiation into usable electricity.
But the average efficiency of a solar panel is around 15-18%. How can we increase the panel efficiency? How can we reduce reflection of incident solar radiation ? This is where Albedo comes into help.
Photovoltaic cells are used in solar panels to absorb the incident solar radiation. The solar panels not only absorbs the incident radiation, but they also reflect a significant percentage. The Albedo value denotes the ratio between the reflected and incident radiation on a solar panel.
The Albedo value is dependent on the characteristics of the material. Light-coloured materials such as silver foil and white pebbles have a higher albedo that is high reflective capacity compared to others like grass or dark body. Sometimes Albedo of the location plays an important role in case of a Bifacial solar panel.
Measuring Albedo in PV cell
As the term Albedo refers to a solar panel that reflects some of the incident radiation. An Albedo in PV cell with a 0 albedo signifies that its surface is entirely black and the body absorbs radiation to its maximum capacity, On the other side the value of one means its highly reflective. In measuring Albedo of a PV cell, an Albedo-meter, which has two parts, is used as shown below:
- A pyranometer which faces downwards. This is connected to measure particular Albedo of PV.
- A pyranometer facing vertically upwards.
An Albedo-meter in Use (Fulcrum 3D)
Albedo of a PV cell characteristics are dependent on the diffusion and reflection characteristics, especially for bifacial solar panels. A low reflection and diffusion value optimize the quantity of radiation incident on the surface. The bifacial panels have panels employ both front and rear sides meaning, an Albedo of a PV cell of that nature is more efficient.
The Efficiency of Albedo of a PV cell
In this case, we will investigate Albedo of a black PV cell with 18% efficiency. Consider due to the albedo, the solar panel generates 5 kilowatt-hour (kWh) calculated from the equation (1/18*1kWh).
However, Due to the Albedo, the PV cell only generates 1KwH electricity while the other 4kWh is lost as heat. The values obtained can be compared to a conventional power system (non-solar PV). If you make use of Albedo in a productive manner, then every kWh generated helps prevent the dissipation of 690 grams of carbon (IV) oxide into the atmosphere. Albedo not only increases your panel efficiency, it also helps reduce pollution.
Factors Affecting Albedo in a PV cell
Albedo in a Bifacial PV cell increases the energy conversion efficiency since sun rays are absorbed on both sides of the panel. This results in a higher diffusivity which increases the efficiency of the PV cell due to Albedo. The factors affecting the configuration include:
- Solar elevation:
The Albedo values of cement, grass, and sand does not help in increasing solar elevation levels. Surfaces like white pellets, silver foil, and whiteboard result in a higher Albedo value.
The efficiency of Albedo in a PV cell decreases due to dust, dirt, and the effect of shading of the panel. They affect the reflection and absorption capabilities of photovoltaic cells.
The Albedo of solar panels increases during the summer season and decreases during Rainy season.
- Cloud cover:
The effectiveness of Albedo is high when the sky is clear and sunny.
Is Albedo an Important Consideration?
Most people tend to ignore the importance of Albedo while identifying a suitable system to harness solar power. This affects the payback period and the overall efficiency of the solar panel. Be it in green buildings, commercial, or domestic buildings, the consideration of Albedo is inevitable.