So you’ve come this far down the road looking at investing in solar for your business. If it’s still looking good at this stage following all the number-crunching and research, it’s time to start getting down to the nuts and bolts of things. This is where things start to get a bit more technical.
Roof Installation Planning
The more roof space you have the better. As solar PV is a costly investment, you want to be sure that to maximise the amount of roof space. Flat roofs work best as this will allow the solar panels to be angled adequately for the location, taking into account both the pitch and the Azimuth.
Although all solar PV installations in the southern hemisphere should be facing either true north or have an east/west configuration.
When planning the installation, work on a solar PV output of 200W/m2 for higher efficiency technology. At the bottom end of the scale efficiency will be in the margin of 50W/m2, but ideally, you want to invest in higher efficiency technology to maximise solar output.
Shading is bad news for solar panels so when planning the layout of the panels, identify areas where shading occurs and avoid them when planning the actual layout.
Areas of the roof with raised obstructions or surrounding buildings may also cause shadows throughout the day, so this also needs to be taken into account when planning the layout.
Roof windows will also limit the amount of space for solar panels as they will have to be installed around these areas.
The structural integrity of the roof is probably the most important factor in establishing whether the roof is suitable or not.
Some types of roofs are not suitable for solar PV. These include the older types of asbestos roofs or old roofs where the structural integrity might be a concern. It’s suggested to get a structural engineer to investigate the roof and determine if it will hold the extra weight.
Remember,l solar PV systems have an average lifespan of 25+ years, so if the roof is in poor shape then it’s best to replace it before installing solar panels.
There are many software products on the market that will assist with the optimal solar panel layout taking all the above into account. Some of these tools can even identify roof areas affected by shadows throughout the day for every day of the year.
There should be walkways defined in between solar panel rows in a large installation. This will allow access for personnel to not only install the panels more easily but also access them for maintenance when they need to be cleaned or replaced.
Roof Mounting System
A fair amount of time should be spent on investigating different roof mounting systems. There are various manufacturers available each with unique intellectual property designs that cater for different types of roofs. These mounting systems are designed to be exposed to the elements for long periods of time, and they are also designed to keep heavy solar panels in place during high winds.
The type of roof mounting system will very much depend on the type of roof.
As an example, for a flat roof, one would consider either a ballasted system if the roof can support the extra weight, or else a mechanically fixed system if weight is an issue.
Pitched roofs with Spanish tiles would use a roof hook based mounting system.
Metal roofs use either a clamp-based system that clips onto the roof ribs or a hanger bolt that screws into the wooden roof frames.
In our Solar System Installation Process Ultimate Guide, you’ll find a comprehensive overview of the roof and ground-mounting systems and the requirements for their installation.
Safety Comes First
It goes without saying that working on roof structures and with electricity requires adequate safety precautions to be taken.
Never attempt an installation when the weather is bad as wind can cause the panels to fly off and damage the installation. Worse still, the lives of those performing the installation could be endangered.
Water is also a conductor of electricity so that’s another good reason to stop any installation during bad weather conditions.
Be sure installers always wear a safety harness when working on the roof. Ensure the solar panels are properly grounded to remove the risk of electric shock. It’s also advisable to cover the panels with an opaque covering when wiring them to prevent electricity production. DC current can cause nasty and potentially lethal electric shocks!
Which Solar Panels Should I Choose?
Solar panel efficiency has improved over the years with new generation panels having an efficiency as high as 22.5%. What does this mean though? It means you can get more clean energy production per square meter with higher efficiency panels. With limited rooftop space, it’s always better to opt for higher efficiency panels with higher outputs.
Consider looking at the GCL-P6/72H Multicrystalline panel, it has a power output of 330W and an efficiency of 17.3%. The panel has a 10-year product warranty and a 25-year linear power warranty.
Or else consider the REC Twinpeak 72 cell series line of solar panels. The solar panel has an efficiency ratio of 17.2% and comes in a range of power outputs ranging from 330W to 345W.
Which Inverter Should I Choose?
The main purpose of an inverter is to convert the DC power produced by the solar array into AC power, that can be used to provide power to the building’s internal loads. There are different types of inverters such as micro inverters and string inverters for smaller sized solar PV installations.
With a string inverter, solar panels are connected in arrays and in turn connected to a string inverter. Multiple arrays can be connected to one string inverter.
A disadvantage of the string inverter is that if it fails the whole system will stop producing electricity. Also, if just one of the solar panels fails, is affected by shade, temperature difference or is dirty, it will negatively impact the power output of the whole array connected to the inverter.
Micro inverters are a popular choice and are worth considering. The micro inverter as the name implies is a smaller version of a string inverter but is installed at the solar panel level. Thus, each panel has its own micro inverter.
Micro inverters have numerous advantages over string inverters. They allow all panels to operate at their maximum power and not be affected the other panels, so any panels that underperform due to soiling, shading, temperature differences or even mismatched panels, will have no effect on the efficiency of the other panels.
Micro inverters are also ideal for complex roof layouts where panels are installed at different tilt angles and directions. If one panel or micro inverter fails, then the system will still continue to operate as there’s no single point of failure.
The Enphase S270 is an ideal micro inverter for solar panels rated between 230W and 350W. The micro inverter maximises power output per panel and minimises the impact of shading and soiling of panels. It’s also compatible with 60 and 72 cell solar panels and battery management systems. The Enphase micro inverter also comes with a leading industry 10-year warranty.
Choosing a Monitoring System
A solar PV monitoring system is a vital component of any commercial solar system, even for residential systems. But it’s especially important for commercial systems.
A monitoring system will maximise the power and profit of your investment. It’s rare for things to go wrong with PV systems but when they do, they can go largely unnoticed.
A monitoring system will give you an indication that something is wrong so the appropriate action can be taken. A monitoring system will also provide real-time data on how much electricity is being produced and provide historical data as well.
Enphase Envoy is the in-house monitoring system for Enphase micro inverters. The Enphase Envoy is the brain behind the communication of all system components. The monitoring system allows bi-directional communication to flow between the micro inverters and the monitoring system.
The monitoring system delivers performance data for each micro inverter to the web for viewing and also provides software updates to the micro inverters when required.
Once the number-crunching and feasibility have been completed for a rooftop solar PV system then it’s onto planning the installation. Time should be spent on identifying suitable rooftop space and maximising the amount of power output per square metre.
The appropriate roof mounting system should be selected depending on the type of roof structure. It might also be an idea to get the opinion of a structural engineer on whether or not the roof can support the weight of the photovoltaic panels needed.
Installing rooftop systems does come with safety risks so safety should always be a priority.
It’s also recommended to use high output solar PV panels and consider the use of micro inverters for optimising energy production.
A monitoring system will ensure that the profit and power of the system are maximised by identifying and communicating any failures should they occur. The monitoring system also provides energy production figures in real time so it’s an important component of the overall system.
If you want to see how much solar or battery storage could save you over the next 5 years, then take our solar saving calculator quiz below!
Or talk to an Instyle Solar expert about the best solutions for home energy storage or PV-panels.
Otherwise, head back to the solar blog to find even more great educational content.
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