Solar PV System

Technical Information

Click below for to learn more about each component

1. Panels

Panels

Panels of different sizes, type, power, origins of manufacture, brand, tolerance, colour, material and warranty are available in the UK. And now with thin film and solar tile technology, there is even more to consider when purchasing a solar pv system. Here is an overview…

Firstly there are three main types of panel: Monocrystalline, polycrystalline and thin film. The first two are currently the most commonly used and are manufactured in quite a similar process using crystalline cells made from silicon.

The raw material for silicon is sand, one of the most abundant elements available. However, the process to turn sand into premium quality energy conducting silicon is a complicated and expensive process which involves:

• melting quartz sand in specially shaped furnaces
• adding chemicals and elements, including Boron to positively charge the silicon
• aligning all atoms

This process results in the manufacture of cylindrical shaped silicon ingots.

Monocrystalline panels are made using paper thin wafers cut from a single ingot of silicon, whilst polycrystalline panels are made from cells made from melting several silicon crystals together. Monocrystalline cells are higher in efficiency and this is usually reflected in the price.

Metal conductors and an anti-reflective coating is added to each cell to allow the conversion of solar energy into electricity, before thinly diffusing phosphorus over each, which provides the negative charge.

The cells are linked and soldered together, and glued to a backsheet. After which a layer of glass is added on the front side and it is sealed around the edges with a frame to prevent water and dust affecting the panel. The size and power output of the panel will depend on the number of cells used.

The colour of panels vary depending on whether they are polycrystalline (blue) or monocrystalline (black) and both reflect light differently. The colour of the backing behind the cells (white or black), and the colour of the frame (silver or black), also changes the look/appearance of panels.

A junction box is added to the back of each panel to enable the extraction of the generated energy from each.

All panels are tested against Standard Test Conditions (STC), electrical parameters are recorded and you will find performance details on the model’s data sheet, including details on their warranties and manufacturing tolerance (allowable deviation against the stated power output).

Solar Plants have a panel test rig where we continually test 20 of the leading panels currently available, so that you don’t have to worry about doing detailed research. Our Energy Advisers will talk you through their recommendations.

2. Power Optimiser

Power Optimiser

Power optimisers are intelligent devices that enhance the overall performance of a solar PV system (over that of a traditional system), communicating detailed cell level performance data to the inverter, and to an online or app-based monitoring system.

A SolarEdge Power Optimiser harvests the maximum amount of energy from each panel by using Maximum Power Point Tracking (MPPT) that varies the electrical operating point of the modules, so that panels are able to deliver maximum available power.

This differs from a traditional system where the inverter would perform this exercise for the entire array. In traditional systems, the inverter will manage a constant flow of solar energy through all panels in the string (series). Because panels vary in terms of performance (due to manufacturing tolerance, partial shading etc.) this conventional way of installing a PV system means some panels will be restricted from performing at their maximum ability, resulting in lower efficiency. Power Optimisers, however, allow each panel to operate in isolation, therefore, if one panel is affected by shading for example, it will not affect the rest of the panels in that string. The effect of this has seen some customers improve their output by nearly 25% when upgrading from a standard stringed inverter system.

Power optimisers also allow for a more flexible layout of panels including different orientations, pitch, panels and groupings.

3. Inverter

Inverter

A solar PV inverter is the hardest working part of a grid-connected solar PV system.

Its main purpose is to convert the direct current (DC) energy produced by solar panels to alternating current (AC) for use in a home or business, as well as regulating the flow of power being produced by a string of panels.

There are three main types of inverter: Standard stringed inverter, micro inverter and power optimiser/SolarEdge inverter.

Standard stringed inverter:

Stringed inverters use maximum power point tracking (MPPT) to get the maximum possible power from the PV array. Silicon cells produce a non-linear output known as an I-V curve and the inverter samples the output of the panels to determine the flow of energy through the string and obtain maximum constant power for any given condition. If all panels are working within the positive manufacturing tolerance, and are without damage, soiling or shading, then a standard string inverter functions well enough. However, if there is an issue with any of the panels, the inverter will regulate the flow of energy to that of the weakest performing panel, and total generation can be greatly reduced.

Micro-Inverters

Micro inverters do the inversion from DC to AC on a single panel, and therefore one is required per panel. As the inversion happens at source, there is no need for a separate inverter thus removing the single possible point of failure.

As the panels are wired in parallel rather than series, the underperformance of one panel will not have a negative effect of the rest of the system, and as each panel operates in isolation, the architecture allows for a more complicated array layout.

As each micro-inverter is essentially a smaller version of a standard inverter, they are more expensive than a conventional inverter system.

Power Optimised Inverter system (SolarEdge)

The SolarEdge HD Wave inverter is a hybrid system. As power optimisers on the back of each panel do the MPPT, the supporting inverter doesn’t need to work as hard. Its award winning power conversion technology has lead to a reduction in the magnetics and heavy cooling components making it the smallest inverter currently on the market with a record breaking 99% efficiency.

In addition, a data monitoring receiver collects all data from each power optimiser about the performance of each panel, which in turn is sent to the SolarEdge monitoring platform for access by the homeowner, installer and SolarEdge to help identify and rectify cell level performance issues.

4. Generation Meter

Generation Meter

A solar PV installation requires an approved generation meter to accurately record the power generated by your system. This approved meter needs to be installed by an MCS registered electrician/installer to allow homeowners to qualify for the Feed-In Tariff, and it’s the reading from this meter that is sent to the energy supplier every quarter.

5. Consumer Board

Consumer Board

Every home has a consumer board (otherwise known as a consumer unit or fuse board) to control electrical energy and to protect different circuits.

Each circuit (ie downstairs sockets, upstairs lights) will have a RCD (Residual Current Device), which switches electricity off if there is a fault, and is designed to protect against the risk of electrocution and fires caused by earth faults.

The supply of solar PV generated energy from your panels will pass through the consumer unit and requires its own RCD. If there is no spare way (space for a RCD) available, we add our own ‘sub-board’ thus creating a new circuit. This is normally a 2 or 3 way consumer board, as we are obliged by MCS to leave a spare way after we have carried out an installation

6. Appliances

Appliances

When your solar PV is generating clean energy, your appliances will use this energy over grid supplied energy. If your PV system is not generating enough to power your appliances, then electricity from the grid will be used to top up what is required.

7. Batteries

Battery Storage

Solar PV batteries work by storing solar PV energy that would ordinarily be sent back to the national grid for use when your solar is not generating, maximizing the self-consumption of solar and reducing bills and the reliance on energy suppliers further.

They work by converting the excess AC energy back to DC power for storage in lithium ion or equivalent battery technology. Some solar batteries have their own inverter for doing this, others require an additional inverter to run this process.

There are many types, brands and sizes of battery, of which more information can be found on our battery technical page.

The choice is yours

Five ways to install your solar PV

Apart from thatched roofs, there are not many instances where PV panels cannot be installed. And now with in-roof options, a PV system can be seamlessly integrated into your roof, giving a flush, waterproof, sleek-looking finish.

We also fix solar panels to flat roofs, or on the ground when a roof space is not viable or available.

On Roof

Concrete Tiles

Concrete Tiles

Concrete tiles are commonly used, and as such are easy to retro-fit to a building. Once the placement of panels has been measured out, our qualified roofers lift the relevant tiles to find the joists to enable them to fix specialist brackets that will support the rails. Once secured, the tiles are replaced and the rails affixed. Owing to our comprehensive survey, our roofers always have a supply of extra tiles available just in case any are broken in the installation process.

Slate

Slate

There are several ways of installing panels to a slate roof. We prefer to use the SolarFlash fixing system that provides a secure and weather-tight fixing whilst protecting the integrity of the roof. Once the placement of the panels has been measured out, our qualified roofers lift the relevant tiles to find the joists to attach the SolarFlash fixings that will hold the rails. Once secured, the tiles are cut to size around the fittings to enable flexibility and movement of the panels in high winds without cracking or breaking tiles.

Owing to our comprehensive survey, our roofers always have a supply of extra tiles available just in case any are broken in the installation process.

Composite

Composite

In a similar vein to slate, we use the SolarFlash fixing system to provide a secure and weather-tight fixing.

Standing Seam

Standing Seam

The fixings for standing seam roofs are specialist bolts that screw on to the seam, without penetrating the roof itself. Our qualified roofers measure and draw out the desired array layout to ensure the panels are aligned horizontally to follow the line of the roof. They place the bolts along the measured line to ensure the rails are attached securely, and then attach the panels

Flat Roof

Flat Roof

Using market leading Solion mounting frames, we are able to design a rooftop array that is perfectly positioned, stable, streamlined and that doesn’t require any penetrating of your roofing material.

The design of the frames ensures that wind resistance is at a minimum, with wind tunnel studies showing that they have the lowest Coefficient of lift of any mounting system in the world.

In Roof

In Roof

As solar power moves beyond Government subsidy to become a home improvement option, its kerb-appeal is becoming more and more important. Integrated solar has come of age, and with the highest quality and aesthetics now come at a price competitive with above-roof solar.

Viridian’s ‘Clearline Fusion’ in-roof mounting system achieves the highest fire rating and exceptional wind resistance without the need to purchase extra roofing battens or to modify the roof below to have a fire rating. A patented connection method means that panels link together to create a weathertight seal and roof fixing.

We can install Clearline Fusion on most tiled roofs and standing seam roofs.

Ground Mount

A Frames

A Frames are metal structures that are either driven into the ground using ground anchors or concreted in, and are more suitable where there is need to concentrate panels in one space (ie panels cannot be spread out/lack of ground space). The benefit of A frames is that panels can be perfectly positioned in terms of orientation and pitch to ensure maximum generation.

If your panels are far from the inverter/consumer board, then there will be the need to dig a trench for the armored DC cable back to the property.

Renesol

The Renusol tub is a cost effective and versatile panel mounting system for flat surfaces (ground or roof). Due to the tubs ability to hold ballasting material that will weigh the panels down, the tubs are a secure and wind resistant option that doesn’t require penetration of the land or other flat surface. As each tub is separate, each panel can be positioned individually and perfectly arranged.

If your panels are far from the inverter/consumer board, then there will be the need to dig a trench for the armored DC cable back to the property.

Your solar powered future is just a few clicks away.

0800 856 2200

0800 856 2200