Components of a PV Solar Energy System
A photovoltaic (PV) solar energy system consists of multiple components. Each component has a specific function, whether it would be to generate electricity or to ensure that your system stays firm and secure. The components that make up a solar energy system can also vary, depending on the purpose of the solar energy system and the type of components used. Some components can serve multiple functions at once, making others redundant. We’ll explain what components make up a PV solar energy system and their role in your system.
Photovoltaic (PV) Solar Panels
Most people associate a solar energy system with its photovoltaic solar panels. These panels are the core component of your solar energy system. Their function is to convert sunlight into electricity through the photovoltaic effect. The sun’s rays interact with a semiconductor, which is the solar cells that make up the photovoltaic panels. This interaction causes the electrons to move and generate electrical current, which is then captured as electrical current by wires and sent down to the line to the other components. Solar panels can come in different types:
- Monocrystalline Solar Panels have solar cells made of a single silicon ingot to form a crystal. This solar cell structure makes them the most efficient solar panels, with better low light performance, and reduced loss of efficiency. Making them some of the best performing solar panels. Because of their high production cost, they are among the more expensive solar panels available on the market.
- Polycrystalline Solar Panels are made up of fragments or shards of silicon. This structure gives these solar panels the speckled blue color but reduces their efficiency compared to Monocrystalline solar panels. While this structure allows the panels to be cheaper to produce and purchase. You may need more panels to generate the power you need.
- Thin-Film Solar Panels are the easiest and fastest solar panels to manufacture. They can be made with different materials such as amorphous silicon (a-Si), cadmium telluride (CdTe), or copper indium gallium selenide (CIGS). This allows the panels to be thin, flexible, cheap, and easy to install. However, they have shorter lifespans, and their efficiencies can be close to or less than other panel types. However, their thermal coefficients are great, and with advances in manufacturing, they could be as good as high-end panels.
The solar panels that are part of a solar energy system will be referred to as a Solar array. These panels will be connected as a series string. However, the power of all of the solar panel series will need to be combined before going any further down the system.
The function of the combiner box is to take the current from the multiple strings of solar panels and combine these multiple series strings into one parallel circuit.
A direct current (DC) disconnect switch is installed between your solar array and the inverter. The role of this switch is to safely cut the inverter off from the solar array. Your local utility company may require the disconnects to be accessible by their personnel if your solar energy system is grid-connected.
Your panels will need to be mounted to stay securely in place and maintain proper alignment with the sun. Whether your solar panels are rooftop or ground-mounted, there are different types of mounting hardware that are used to mount solar panels and route cables:
- Ballasts are a simplified mounting solution that utilizes ballasted weights to keep solar panels held in place on a flat surface. These are mainly used on flat roof homes and commercial buildings.
- Racking is a mounting solution that utilizes mounts, rails, and clamps to secure the solar panels in place. These can be used for both ground and rooftop installations.
- Tracking systems are a step up from racking mounts that use motors to rotate the solar panels. These can come with single-axis or dual-axis tracking.
If your solar energy system will have an energy storage solution like a backup battery or a battery bank. Your solar energy system will need to be able to properly charge the batteries. The function of a charge controller is to regulate the voltage and current from your solar array that charges the batteries. Without a charge controller, the batteries in the system can be overcharged and damaged due to the varying performance of solar energy systems.
Charge controllers will vary depending on the maximum voltage and current specifications. The size of your solar energy system will determine the number of charge controllers that are needed. Generally, charge controllers have a high current rating of up to 40 amps. So you may find that you won’t need more than one controller unless your system is large.
Energy storage is one of the benefits of solar energy. With the capability to store energy, you will have a reliable source of power both for emergencies and to supplement any reductions in energy production. Solar energy systems have battery banks, an array of interconnected battery units that function as one whole battery. The type of batteries used in solar energy systems is classified as deep-cycle batteries. The batteries used can range from lead-acid batteries such as flooded lead-acid (FLA) to sealed absorbed glass mat (AGM).
Nowadays, battery banks on offer from companies such as Tesla, Enphase, and LG use lithium batteries and can come with additional capabilities such as smart switching in case of power loss, and Smart Management Modules (SMMs).
However, the energy that comes from your solar panels and battery is direct current (DC). It will need to be converted to alternating current (AC) to be used by your household. The role of the inverter is to convert the current for household use. It also directs the flow of energy to your home from your solar panels, batteries, or from the grid if your system is grid-tied. There are different types of inverters that are used in solar energy systems:
- String inverters (Central Inverters), are designed to deliver AC power from a string of solar panels to your home and electricity grid. However, with string inverters, the efficiency of the entire system will be affected by the worst-performing solar panel. So if one panel in a string is shaded, the other panels exposed to sunlight will perform the same as the shaded panel.
- String Inverters + Power optimizers is a combination of string inverters with small power optimizer units on the back of each solar panel. Power optimizers make it so if one of the solar panels is shaded, it will not degrade the output of the entire string.
- Microinverters are small units underneath or built into each solar panel instead of one big inverter for all solar panels. This allows each solar panel to perform individually at its best and always converts at full capacity. They allow you to analyze the performance of each solar panel. With this capability, it comes at increased costs compared to string inverters.
Next to just converting power and directing the flow of electricity, inverters also have additional functionality. Solar islanding and anti-islanding capabilities can be found in some inverters. It allows a household to operate on its own in case of an electricity outage, without the risk of sending electricity down the line.
Safety and Grounding Equipment
Safety and grounding components are important in a solar energy system. Whether they are in-built into your inverter or as separate components, they are often considered mandatory parts of your system. Safety equipment and measures can include:
- Arc Fault Protection is done by an arc-fault circuit interrupter (AFCI) or arc-fault detection device (AFDD). These devices can detect the difference between the harmless and dangerous electrical arcs in your electrical system. If the AFCI detects a dangerous arc, the AFCI opens its contacts and de-energizes the circuit.
- AC Disconnect Switch is required by the National Electric Code (NEC) on the AC side of the inverter. It is needed to safely disconnect and isolate the inverter from the AC circuit for maintenance and troubleshooting. Your utility company may require this if your system is grid-tied.
- Grounding is an important safety feature in any electrical appliance. Grounded devices won’t be affected by the excess current, as it is diverted into the ground and dispersed there. Some states may even mandate that your home’s electrical panels are fitted with a whole-house surge protector.
- Rapid shutdown is a mechanism that stops your solar energy system from working if there is an issue with your home electrical system or solar energy system. Solar inverters are capable of automatically shutting down once an issue is detected.
These safety features should be prioritized for your solar energy system. Arc faults are one of the leading causes of electrical fires in homes. Making sure that dangers such as these can be detected and dealt with will ensure the safety of you and your family, household, emergency responders, and technicians.
These components function together to make up your PV solar energy system that powers your home. While your particular solar energy system may not include all of the components listed. You will now know how they function and can benefit your system.
Get started with solar energy today
If you are looking to start your transition to solar energy, we are here to help. Our website also has a free online estimate tool that generates a personalized report for you from a simplified questionnaire. That report will contain the potential savings you can net, and the cost of a solar energy system installed on your property. You can also contact us directly via phone at +1 (602) 363-8919 or via email at Scott@elitesolarenergy.org for more information regarding solar energy for your property.