EnviroGroup were chosen to provide a maximum system for the roof at the Islam Museum on Anderson Road Thornbury. Originally, the museum wanted a 30kW with the possibility of later expansion but as funding became available, the brief was changed to maximum coverage of the roof up to 100kW. The original 30kW design was easy as we had plenty of roof area to lay panels and an excellent modern main electrical services room for the inverter. With the new addition, we had to make many concessions to the design.
System size
Whilst the roof area allows for a full 100kW of panels, the guidelines from our structural engineers limit the panel placement to allow for wind loading effects and dead weight of the system. To complicate matters, the roof has a fall arrest wire running in the centre of the roof sheeting for almost the full length of the building. This meant we either had to relocate the wire or alter the panel layout to accommodate the clearances required to ensure the fall arrest system wasn’t compromised. Since moving the wire would result in further delays and regulatory assessment, we opted for the latter and this reduced the total system size we could install. The result was a 84kW solar system.
Commercial grade solar panels
We chose to use our main commercial workhorse panel, the 330W Trina Honey M Splitmax panels, 256 of which would drive three Fronius Eco 27kW inverters. This gives an inverter ratio of 1.04 which is a little under the 1.3 we aim for but presented us with the best stringing outcomes.
This is where it pays to not be too focused on a single brand. We oscillated between the Ecos and SMA Tripowers but the Fronius’ gave us a neater configuration. Either way the customer wins. However, with the extended system size, the available space in the switch room could not support three inverters plus a Network protection gridbox so we had to move them all to the outside wall.
The Trinas at 330W are starting to look slightly small considering other options, even within the Trina range but once again we had to make choices about cost, size and voltage and we have had great success with this panel over the last year. All in all, we are happy with the design and, as usual, our in-house team completed a text-book perfect install.
We will continue to monitor the performance of the system and part 2 of this project will be an analysis of the energy and financial outcomes.
