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Types of solar equipment, explained

clock 9 minutes | 10 Nov 2021

solar panel catching rays from a sunset

What is the process of harnessing solar energy? Knowing that will help with understanding solar energy systems and the solar power equipment needed. We’ll explain as we go along, but in a nutshell:

Step 1: Sunlight activates solar panels, which generates photovoltaic (PV) charge

Step 2: The charge initiates a direct current (DC)

Step 3: The DC is converted to an alternating current (AC)

Step 4: The AC power is either used to immediately to power homes and businesses, stored in a battery or stored on the grid for later use.

Now let’s look at the equipment solar power systems rely on, and how these pieces of equipment work. Residential solar systems and commercial solar system components are the same – they’ll just vary in size and number, according to the amount of power needed on a consistent basis.

PV solar panels

The purpose of solar panels is to generate energy. How does it do this? Solar panels are made up of photovoltaic cells, also called solar cells. The grid you see on a panel – also referred to as a solar module – is comprised of these cells. It’s these cells that do the work to generate power.

Materials used in solar panels are at the centre of the process. Typically, the panel is constructed of a layer of silicon photovoltaic cells. Silicon is a semi-conductive material, which converts light into electricity in an efficient manner. The sunlight hits the silicon cells, agitating electrons. This PC charge generates direct current (DC).

Solar-panel components consist of a conductive metal frame, a protective glass casing surrounded by film, and wiring. The panels are arranged together into “arrays,” which is an ordered series, for optimal effect. This array forms the solar panel system.

solar panel system array forms

The silicon n-type (negative) and p-type (positive) as depicted here are sandwiched together. This molecular disparity produces voltage when the panel is exposed to light.

Monocrystalline solar panels vs polycrystalline solar panels

Both of these types of solar panels are silicon. Polycrystalline consists of tiny crystals. The structure is disorderly, which makes the silicon grainy. The result is that polycrystalline solar panels cost less than monocrystalline solar panels and performs with less efficiency.

Monocrystalline silicon requires more processing. It’s one large crystal, so the molecules are well ordered. Consequently, the silicon has a higher purity and does a better job of converting the sun’s rays into electricity. This solar panel material costs more, as more processing is involved and the quality and aesthetics are better.

Thin film solar panels

Solar panel sheets are one of the three types of cells. It’s cheaper and as you’d expect, lighter than the other two types. It consists of a thin layer of photovoltaic material on a substrate, usually glass. The photovoltaic material varies but are usually amorphous silicon (a-Si), copper indium gallium selenide (CIGS) or cadmium telluride (CdTe). Thin film solar panels are incredibly inefficient, and therefore require a large amount of space to supply energy.

Voltage: solar cells and panels

Solar cells are wired together, increasing the panel’s ultimate voltage output. Power output will vary, but a typical solar cell produces 0.46 volts. The number of cells that make up a solar panel vary, but here are the corresponding volts:

Number of cells Volts
32 14.72
36 16.56
60 27.60
72 33.12
96 44.16


Inverter

The DC generated by the solar power has to be converted to AC, the standard flow of energy. This is the job of the inverter, the brain of any solar panel power system. At this point, it helps to understand what it means to be on-grid or off-grid.

  • Off grid: There is no connection to the grid. Reliance is entirely on the sun for energy. The converted AC power goes directly to the site and any excess electricity is stored in a battery for later use. Inverters for off-grid use will need a battery charge controller.
  • On grid: Below illustrates an on-grid, or grid-tied, setup, which means the excess power generated is exported to the electricity grid. In essence, the customer uses what’s needed and sells the excess electricity to their utility company to reduce their bills for the energy they do use.

We explain the different types of inverters in What is a solar inverter? How does it work? For now, here’s an overview of what those inverters are:

solar inverters working diagram
  1. Hybrid: This is a solar inverter with battery storage. That is, a hybrid inverter functions as both a solar battery and an inverter for electricity. This type of inverter stores your excess power for later use.
  2. String inverter: A solar panel string inverter involves a string of solar panels wired together. This means if shade or objects, such as leaves, cover one panel, then the power output for all panels are affected. Power optimisers attached to each panel can mitigate this problem, however.
  3. Microinverter: Microinverters are installed on each solar panel, through some can handle two to four panels. This is where the power conversion takes place. The benefit of microinverters is that each panel’s performance does not hinge on another panel.
  4. Central Inverter: Operates like a string inverter, but on a much larger scale. These are used for industrial applications and mount on the ground rather than a wall.

Power optimiser

The maximum power created by each PV solar panel varies due to factors such as temperature, positioning and the amount of sunlight. With a string inverter, the power generated is based on the worst performing panel, the panels are wired together. If shade falls on one panel, diminishing its output, then all the panels’ performance will follow suit.

To get around this problem, power optimisers are installed on each panel. They optimise the harvest of electricity with a technology called maximum power point tracking (MPPT). The maximum power of each panel is tracked in real time. MPPT adjusts the presented load to keep the solar energy system operating at its peak efficiency point.

power optimiser and inverter diagram

The electricity each panel generates is regulated before it’s sent to the inverter. This allows the inverter to efficiently process more electricity.

Charge controller and storage battery

Solar-system requirements are different for on-grid and off-grid systems. Naturally, solar panel designs generate the most energy during daylight – often, enough that users have a surplus of electricity. For people with off-grid systems who rely purely on solar power, a storage battery enables them to use that energy in the evening or store it for a later date rather than let it go to waste. The battery ensures they’ll have power when they need it, even in winter when days are shorter. (However, it’s always a good idea to have a back-up power source, such as a generator.)

Function of charge controller

In off-grid set ups, a charge controller is the brain of the operation. It keeps batteries from over- charging and is responsible for the system’s performance.  Also called a charge regulator, the charge controller regulates the voltage and current coming from the solar panels and going to the battery or if used, a battery bank. It’s the charge controller than keeps storage batteries fully charged.

solar panels with battery bank diagram

A storage battery can also be useful for people with a grid-tied system, though it’s not essential as it is for off-grid users. Smart solar battery systems monitor the customer’s electricity usage. If the customer is in need of the excess energy, it diverts to them instead of to the grid. If a demand exceeds what the system is capable of, the battery system disperses the stored energy.

Bi-directional utility meter

A grid-tied, solar power system installation needs to include a meter designed for the job. Consider it one of the basic components of solar PV systems.

Traditional meters only show the amount of electricity customers use. A bi-directional meter shows the activity on both sides – the customer’s and the utility company’s. It connects users to their system, showing them how much electricity their system is generating, how much they’re using, how much they’re transferring to the grid, and how much they’re buying from their electric company.

Transferring excess energy to the grid enables customers to store it. They’re given credits by their utility company. When they need the energy, they cash in the credits. This is called net metering. Meters connected to the internet make it easy for customers to check their energy activity and net metering.

Racking

PV system installation is critical to performance. There are different types of solar panels, but underneath them all is solar racking or solar mounting. Racking transfers the weight of the solar panels to the roof. The weight must be evenly distributed and fixed securely to withstand heavy winds. Panels are installed parallel to the roof with a few inches gap. The racking is typically made from aluminium for its light weight, which is essential for rooftop installations. It’s also strong, durable and corrosion resistant.

Download free CADs and try before you buy

Download free CADs and request free samples, which are available for most of our solutions. It’s a great way to ensure you’ve chosen exactly what you need. If you’re not quite sure which product will work best for your solar equipment project, don’t worry. Our experts are always happy to advise you. Whatever your requirements, you can depend on fast despatch.

You can also learn more from our Quick guide: components for your solar PV system.

Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.

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