Do you intend to install a solar energy system? If so, you might want to know more about the solar panel, or the device that drives PV systems, as solar installations are also called. In view of that, we prepared this comprehensive guide on the working of solar panels and their different types. So, let’s dive right in, starting with the solar panel meaning.
What is a Solar Panel?
The solar panel is a photovoltaic device surface and that can generate an electrical voltage and current using the sun’s rays. You’ll often see it adorning the rooftops of homes, businesses, or placed close to the ground in solar farms.
When solar panels are strung together in a PV system, they are commonly called a solar array and either connected in series or parallel. Most often, an array is what you use to power your home or business. Single panels, on the other hand, are typically used to run single and low power devices.
What are Solar Panels Made Of?
The main parts of a solar panel are: tempered glass top, encapsulation, solar cells layer, frame, back sheet, frame, and the junction box. Here’s more about them.
- Glass top: this part is made of strong glass and an antireflection layer. It provides protection while also reducing the amount of reflections.
- Encapsulation: a layer of protection, usually plastic, that shields the power generating cells.
- Solar cells: this is here electricity generation takes place.
- Back sheet: the solar panel back sheet offers both protection and electrical insulation.
- Frame: made using aluminum to make it lightweight, the solar panel frame is meant to offer the structural strength it needs to stay together.
- Junction box: contains the connectors and cabling that help connect the panel other panels and circuits.
Types of Solar Panels
Solar panel manufacturers use various technologies to make the device. This gives rise to different types of panels with different characteristics. The types of solar panel that you can obtain today include the following: mono-crystalline solar panel, polycrystalline solar panel, thin film solar panel, and PERC solar panel.
The mono-crystalline solar panel is named so for using single, pure silicon crystals in its energy generation cells. For that reason, these types of solar panels are characterized by a black or dark color and octagonal cells.
The mono-crystalline panel is the most basic of all solar panel types. It’s also quite efficient, converting more sunlight into power than the polycrystalline type discussed below. However, it presents a bigger challenge to make—and costs more.
The polycrystalline solar panel, as its name directly implies, feature many silicon crystals in a single cell. Even though that makes them easier to manufacture, these types of PV panels are less efficient, meaning they convert less sunlight to electricity than the mono crystalline type.
The polycrystalline solar panel is also less expensive, seeing that it’s easier to produce. In terms of application, it suits less demanding situations where affordability is more appealing than higher energy generation efficiency. You can identify polycrystalline panels by their characteristic blue color.
Thin Film Panel
The thin film solar panel is made by depositing a layer (or multiple layers) of a photovoltaic material onto a surface. The surface can be glass, plastic, or metal. On the other hand, different materials may be used for the photo sensitive layer, giving rise to different subtypes of the panel that include:
- Amorphous silicon solar panel
- Cadmium telluride solar panels
- Copper indium gallium selenide
Compared to the mono and polycrystalline types, the thin film panel is the less efficient option. As you can guess, it’s also the most affordable. That’s in addition to being lightweight and available as a flexible panel that you can use in unique applications.
PERC means Passivated Emitter and Rear Cell. These types of solar panels basically feature a layer underneath them, or on the back side, which also makes them go by the name “rear cells”. This layer serves to reflect back the amount of light that would otherwise go through a typical panel.
Because of the added rear layer, the PERC solar panel is more efficient. Normally, the reflective layer is added to the mono-crystalline panel, increasing its energy generation efficiency to even higher levels. This type of panels is mostly used in commercial power generation systems.
How do Solar Panels Work?
Solar panel operation is typically based on the principle of photo-excitation. This is where light energy packets (called photons) excite and dislodge electrons from the atoms of a material. In a solar panel, this causes an electric current to flow. Most panels today are constructed using silicon, so that’s what well illustrates how solar panels work.
- A typical solar panel is made up of single power generating units (called cells) connected together. Each cell is composed of two thin, silicon layers.
- One layer (and which forms the topside) is a P type semiconductor made by doping it with phosphorus.
- The other side is the doped with boron to make it deficient of electrons and named N type semiconductor.
- The P layer has an excess of electrons, which makes it negatively charged.
- The N layer contains empty spaces for electrons. These are called holes.
- When joined together, the two layers form what’s called a PN junction.
- This junction creates an electric field that can only allow electrons to flow in one direction.
Work Step by Step
Let’s now see how a solar panel works, step by step. This will give you an idea of what happens from when the sun shines on the panel to when your electric load power up.
- When sunlight hits the solar panel surface, it knocks electrons off of the silicon atoms.
- The knocked electrons are now free to move.
- However, because of the electric field that exists in the PN junction, these electrons cannot travel through the silicon layers.
- When an external circuit connected to the panel (load), the free electrons can now find a path to flow in.
- The electrons will then flow through the load via several conductors placed at each cell.
- This creates what’s called an electric current
The solar panel working produces what’s called direct current DC. This can only be used by a few devices. To make it more usable, the current is changed to AC or alternating current. This requires the use of a device known as the solar inverter.
How Do Solar Panels Work At Night?
Can solar panels work at night? Let’s see. At night, the sun is not shining. Since the panels depend on light energy to work, it means three are no electrons that are being released and no electricity is flowing in the external circuit. At this time, the panel cannot power your load or charge a storage system.
Note that the amount of electricity being produced by your solar electricity panels is directly proportional to the amount of light falling on its cells. At dusk, this amount falls considerably until the early morning when generation gradually increases.
Solar Panel Uses
With ability to produce current from sunlight, solar panels can be used to power virtually anything that uses electricity, provided the amount of power being generated by the panel is within the power consumption rate of the device in question. Typical uses of a solar panel include the following.
- In homes, solar panels are used to power anything from lights and kitchen appliances to HVAC systems and virtually any type of electrical device.
- Businesses may also install solar power generating panels to power various loads.
- Large solar farms use large panels to generate electricity for distribution to customers.
- Solar panels are today being used to provide power at EV charging stations
- Some electronic products are equipped with mini solar panels to power them. These include calculators, radios, and so on.
- Solar power panels are normally installed on space vehicles to help generate electricity while up there in space.
The solar panel, which is also called photovoltaic module, is a common device in the modern world. It allows the generation of clean energy, in addition to providing for a less costly way to produce power. With the world moving toward greener sources of electricity, solar panels are becoming even more popular, with their use being seen both in homes and businesses.