Solar panels, or photovoltaic (PV) panels, are made up of several key components that work together to convert sunlight into electricity. Here’s a breakdown of the main parts that make the magic happen:
Imagine you’re running a lemonade stand on a sunny day. This scenario can help us understand how solar panels turn sunlight into electricity through the photovoltaic effect.
Lemonade Customers (The Sun)
The sun is like a stream of eager customers lining up for refreshing lemonade. These customers represent photons, the tiny particles of sunlight that travel to your solar panel.
Lemons (Solar Cells)
The lemons you use to make lemonade are like the solar cells in a solar panel. Just as lemons are the essential ingredient for making lemonade, solar cells are the key components that convert sunlight into electricity.
Lemon Squeezer (Photons Energizing Electrons)
When you squeeze lemons to extract juice, it’s similar to photons hitting the solar cells. Imagine each photon as a strong squeeze that extracts a bit of energy (lemon juice) from the solar cells.
Lemon Juice (Excited Electrons)
The lemon juice you collect represents the excited electrons in the solar cells. When the photons (customers) hit the solar cells (lemons), they excite the electrons (extract lemon juice), freeing them up to create energy.
Lemonade Glass (Electric Field)
Now, you need a glass to hold all that lemon juice, just like solar cells need an electric field to organize the excited electrons. This electric field ensures that the electrons (lemon juice) are directed and ready to flow.
Pouring Lemonade (Electric Current)
Pouring lemonade from the glass into cups for your customers is like the electric current flowing through a circuit. When the solar panel is connected to a circuit, the electrons (lemonade) flow out, creating a stream of electricity.
Happy Customers (Powering Devices)
Finally, the satisfied customers enjoying their lemonade represent the devices and appliances powered by the electricity generated from the solar panel. The happier the customers, the more successful your lemonade stand (solar panel).
1. Monocrystalline Solar Panels (Mono-Si)
Description: Made from a single continuous crystal structure called an ingot
Appearance: Typically dark black with rounded edges.
Efficiency: Generally has high efficiencies in low-temperature conditions, often exceeding 20%.
Advantages: High efficiency, longer lifespan, and better performance in low-light conditions.
Disadvantages: More expensive due to the complex manufacturing process. Due to the manufacturing process, the solar cells are round and to fit more cells on a rectangular panel the cells need to be cut to make them square which leads to material being wasted. They do not have a great temperature coefficient.
2. Monocrystalline PERC Solar Panels (Passivated Emitter Rear Cell)
Description: Made from a single continuous crystal structure called an ingot
Appearance: Typically dark black with rounded edges.
Efficiency: Generally has high efficiencies in low-temperature conditions, often exceeding 20%.
Advantages: High efficiency, longer lifespan, and better performance in low-light conditions.
Disadvantages: More expensive due to the complex manufacturing process. Due to the manufacturing process, the solar cells are round and to fit more cells on a rectangular panel the cells need to be cut to make them square which leads to material being wasted. They do not have a great temperature coefficient.
3.Polycrystalline Solar Panels (Poly-Si)
Description: Made from multiple silicon crystals melted together.
Appearance: Usually blue with a speckled, mosaic-like appearance.
Efficiency: Lower efficiency compared to monocrystalline
Advantages: More affordable due to simpler manufacturing process, good performance in various conditions.
Disadvantages: Slightly less efficient and larger for the same power output as monocrystalline panels.
4.Thin-Film Solar Panels
Description: Made by depositing one or more thin layers of photovoltaic material onto a substrate like glass, plastic, or metal.
Types: Includes amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium selenide (CIGS).
Appearance: Typically uniform in appearance, can be flexible or rigid and are often black or dark in colour.
Efficiency: Lower efficiency compared to crystalline silicon panels, usually between 10-12%.
Advantages: Lightweight, flexible, can be used in a variety of applications and performs better in high temperatures and low-light conditions.
Disadvantages: Lower efficiency means more space is needed for the same power output, and the materials used can be less environmentally friendly (in some cases).
5.Heterojunction Solar Panels (HJT or SHJ
Description: Made from a hybrid technology, combining aspects of conventional crystalline solar cells with thin-film solar cells.
Appearance: Typically blue and more transparent.
Efficiency: Has the highest efficiency of the technologies covered here exceeding 26%.
Advantages: High efficiency, longer lifespan (typically a glass-glass panel giving 30 years + lifespan, high bifaciality (can absorb light from both sides) and better performance in low-light conditions.
Disadvantages: More expensive due to the complex manufacturing process but the costs are coming down quickly due to increased production volumes.
1. Temperature Coefficient
Lower temperature coefficients indicate better performance in high heat.
Unfortunately, most top solar panel technologies were developed for Europe’s cooler temperatures, which do not reach nearly as high as South Africa’s. As an example a typical temperature coefficient for a panel would look like this, -0.34%/°C. This indicates a panel would lose 0.34% of power per °C above 25 °C and would gain power below 25 °C. In SA panel temperatures can easily reach 75 °C, which means the panel would lose 17% of its rated power.
2. Performance Under Real Conditions
Panels are rated at standard test conditions (STC): 25°C, 1000 watts per square meter of solar radiation, and an atmospheric condition of 1.5. In reality, panel performance decreases with higher temperatures and different sunlight angles.
3. Angle and Orientation Specific to South African Latitudes
The tilt angle of solar panels should be optimized to capture the maximum amount of solar radiation throughout the year. In South Africa, the optimal tilt angle is approximately equal to the latitude of the location.
Cape Town (33.9° S): The tilt angle should be around 33.9°.
Johannesburg (26.2° S): The tilt angle should be around 26.2°.
Durban (29.9° S): The tilt angle should be around 29.9°.
Pretoria (25.7° S): The tilt angle should be around 25.7°.
For year-round efficiency, the tilt angle can be adjusted slightly:
Winter Tilt: Latitude + 15°
Summer Tilt: Latitude – 15°
Shading and Obstruction in Urban and Rural Settings
Temperature and Weather Conditions Prevalent in South Africa
Maintenance and Cleanliness, Considering Local Environmental Factors
4. Performance Guarantees
Traditional panels offer a 25-year performance guarantee with a maximum 20% efficiency loss. New glass-glass technologies offer a 30-year guarantee with only a 4% efficiency loss, making them more durable and efficient over time. This means that the old saying “cheap is expensive” pretty much sums it up. The more expensive tech will provide a better long-term ROI.
We at EEC are committed to client satisfaction and thus decided to ensure when we recommend a product we have the facts to support our recommendation.
Let’s get back to the facts.
EEC has conducted extensive tests on three types of solar panel technologies: advanced Mono Perc, normal Mono Perc, and heterojunction cell technology, to determine their efficiency and performance under different conditions.
EEC tested two Mono Perc panels from different brands (one less expensive and one premium) and 2 new heterojunction cell technology panels.
The different panels are installed as a permanent installation in order to observe the long-term performance of the different technologies as well as season effects.
EEC’s tests have shown that newer technologies, especially heterojunction cells and premium Mono Perc panels, provide significant efficiency and durability improvements, making them a worthwhile investment for solar energy installations in South Africa. By choosing the right solar panels, you can ensure optimal performance, better returns, and a greener future under the beautiful African sun.
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All Rights Reserved | Designed with Passion by VerdanTech