3 minute read
Light-bulb moment by Leo E, Electrical Engineer, CSR Limited
Light Bulb Moment
More than 120 Members registered for April’s ‘Solar design principles & specification of solar panels and batteries’ webinar presented by Aven Taylor from Bradford Energy.
Here, Leo E, Electrical Engineer, CSR Limited – Masonry & Insulation, NSW, answers 9 questions asked by DMN Members during the webinar.
Q. With regards to the exclusion zone, given that we are in a non-cyclonic region A, what is the exclusion zone at the ridge, from the gutter and the sides?
A. Different racking manufacturers have different exclusion zones to comply with AS/NZS1170.2.
You can work with your CEC accredited designer to select the most suitable racking provider.
Q. Does the semi-integrated system address the overheat issue (e.g. insulated layer)? Or this is something that the designer needs to resolve using separate elements on a case by case?
A. BiPV systems are slightly less efficient than conventional PV systems due to the heat build-up.
Bradford Energy is exploring options to improve air flow for the semi-integrated INLINE systems.
Q. What considerations for installing panels in bushfire areas? (Thinking about gap between panels and roof...)
A. All the solar panels we use are tested to IEC 61730-2:2016 Photovoltaic (PV) module safety qualification and are fire rated. A Bushfire Attack
Level (BAL) is a means of measuring the severity of a building’s potential exposure to ember attack, radiant heat and direct flame contact.
Penetrations on the roof from solar cables should be sealed with suitable BAL rated material.
Q. How much added weight does an average 6kW system add to a roof? Should your roofing structure system be upgraded to suit?
A. Standard bolt-on system should not add more than 20kg/m2 to your roof and racking interface spacings are certified to AS/NZS 1170.1:2002 (R2016) Imposed loadings and AS/NZS 1170.2:2011 (R2016) Wind Loadings. This is normally not a concern to recently built houses.
However, please contact your structure engineer should you wish to conduct a roof structure assessment.
Q. Is there software available that will allow a panel system to be specified for a required output, in terms of pitch and orientation.
A. Almost all the estimation software in the solar industry can generate production reports based on the azimuths and orientations. Alternatively, our sales representatives are more than happy to assist you to estimate solar productions. Q. How fast are the sizes of panel growing in power output? Do you foresee the possibility of 500w panels hitting the markets in the future (10yrs)?
A. Over recent years, panel efficiency has increased from 15 per cent to over 20 per cent which results in a big jump from 250W to 370W.
Although Bradford Energy is not a panel manufacturer and it is challenging to make a major breakthrough in improving panel technology, we are optimistic about the more powerful domestic panels coming to the market in the near future.
Q. Can you discuss emerging technologies using an electric car’s battery to power the home?
A. Some car manufacturers are pioneering vehicleto-grid technology (V2G) and working closely to the government for trail projects funded by
Australian Renewable Energy Agency (ARENA).
This technology can offer great benefits to customers and also help enhance grid resilience and reliability.
Q. I have clients here in Victoria that install 13-15kw systems. I don’t believe they get any restrictions about what goes back to the grid. Is WA different in the way they run solar systems?
A. Every Distribution Network Service Provide (DNSP) has its own network guidelines which stipulate solar connection requirements.
In Victoria, you are normally allowed to install a 13-15kW solar system that can fully export to the grid providing it is a three-phase connection.
However, this allowed kW rating could vary from location to location, depending on the local network infrastructure.
Q. In Perth do the panels have a shading effect on the roof and thereby reduce cooling requirements in the summer?
A. There were studies carried out by researchers and they found the building’s ceiling can be up to 5 degrees Fahrenheit cooler under the array compared with exposed section of roof.
Another benefit to consider when making a purchase decision for a large solar system!
