Information on good Solar PV system design

The Importance of Good PV system Design

Make the most of the sun’s energy and maximise your investment

Energy Smart PTY Ltd systems will operate and generate power in most conditions where there is sufficient light from the sun to enable the inverter to start up. However, there are many factors that can affect how well a given system performs and it is vitally important to design a PV system in consideration of these factors.

This page gives some information on the principal causes of poor performance in PV Systems and should be high on your tick list of things to ask any potential installer.

With the term of the Feed-in Tariff set to 25 years, correct system selection and optimum array placement can mean the difference between a good return and a great return. Choosing the right company to design and install your photovoltaic system can help make that difference.

Shading

Shading has, by far, the most significant impact on Solar PV system performance. The German market for PV systems is approximately 10 years ahead of the UK, due to their established Feed-in Tariff. In a survey undertaken in Germany of 1000 PV installations, shading came out on top for causing reduced yields and was responsible for considerable reductions of as much as 30 per cent and more in PV systems.

Unless the proposed location for your PV system faces due south and has no nearby objects that could cause shading on the PV panels then a full shade analysis will need to be carried out to give a reasonable level of accuracy to any yield forecast.

This can only be done by a competent PV surveyor attending your property and carrying out a detailed survey and any reputable company should offer you this service free of charge. You should expect to receive a detailed report showing clearly the effect that shading has on the output of the system in your particular case.

Every effort should be taken to avoid installing panels in an area affected by shading for any significant part of the day, though in the real world this can be difficult to achieve. In these instances, careful selection of components and configuration of panel strings (groups of panels interconnected) can vastly improve yields.

Quality of components

25 years is a long time and choosing quality components at the outset, can help you reap long term rewards. All solar panels and inverters come with some form of warranty and performance guarantee, but they are by no means equal. It is important for anyone thinking seriously about installing a PV system to ask what kind of guarantees and warranties come with the panels and inverters that are included in the quotation and what is covered in the event of a fault or claim.

Of equal importance is the relative performance of the individual parts and the build quality. Two 230W solar panels produced by different manufacturers could have very different performance levels despite being, at first glance, equal in terms of power output.

Panel layout and inverter configuration

For a given installation, an inverter, together with a specific PV panel can be wired up in a great number of different configurations, any of which can impact on the potential yield of the system. Add to this the fact that there are a huge number of different PV panels and inverters on the market and the options are virtually limitless.

We take the time during the initial visit to identify the things that matter most to you and will produce a number of options based on this information and the data from the technical survey. Each option that we present will be accompanied by detailed simulation and yield forecast figures produced using the industry’s leading PV design software (PVSol Expert).

Our aim is to offer you a choice based on our knowledge and experience of PV systems, all of which are tailored to your individual requirements. We will not push old stocks of cheap panels and inverters bought in bulk like some larger national installation companies.

Location of inverter

Inverters like solar panels are affected by high temperatures. Where possible they should be installed in a cool well ventilated area that is free from dust. In practise, this is not always possible and in some instances, installing the inverter in the roof space may be the only option. However, we prefer to install inverters in a garage or outside of the property in order to improve the efficiency of the inverter in summer conditions when the ambient temperature is higher.

The inverter is a potential point of failure in any PV installation and inverters have an anticipated lifespan of around 10-15 years. This is something that must be taken into consideration when you are considering investing in microgeneration.