 |
| Healthy scepticism? |
 |
| The state of over-gentrification can be judged by the number of sample pots? |
PV Installation
In May 2015 I naively clicked a banner ad on my laptop promising comparative prices for PV installation, I was curious because it was always 'in the plan' but just not a high priority. What I realised the following day was that this was just a sales-lead gathering website for contractors and some of whom also install double glazing, roofing, cavity wall insulation etc.......
Since only a handful of contractors phoned me, I made appointments with 3 or 4 for no obligation quotes. It became apparent that most PV contractors are used to quoting for pitched roofs, where apart from the kit there are 2 fixed variables; roof pitch and orientation, so the 'surveyor' has only to work out how many panels can be fitted. My roof is flat and fairly limited in size, with the pitch and orientation of panels almost infinitely variable - a clean sheet so to speak.
One contractor offered a totally flat layout, which would have necessitated regular cleaning, another proposed a south facing pitched arrangement but by my calculation the arrays were larger than the available roof space. All contractors majored on Warranties, which I found off putting because I wanted a company I felt I could trust, without relying on guarantees that should only be a last resort.
Since I was now fully up to speed on Photo Voltaics from initially very little knowledge, it seemed logical to continue through to an installation. I did a bit of research mainly through trusted Electricians and came up with 3 likely PV Installers.
I had an intelligent 2-way conversation with the surveyor from Solarsense, rather than a sales pitch, who understood that I was after value for money that could be expressed in the payback period and was able to consider all the variables in a flat roof installation.
Solarsense were also experienced and confident in specifying flat roof installations that relied on ballasted frameworks.
A couple of layouts were explored in outline and the favoured one analysed in more detail. The installed layout dispensed with the desire to face due south at an angle across the roof and instead lined 2 rows of panels, pitched back to back and square to the roof layout. This gave a dense layout and the low pitch of 10º (to aid self cleaning) and meant that the panel surfaces would receive light for a wide part of the day with only a small reduction in efficiency due to the low pitch. This arrangement also had the advantage of a fairly streamlined profile, so ballast to prevent uplift and movement could be kept to a minimum, though still weighing a tonne!
In an effort to reduce installation costs I suggested that the house
stairs and rooflight could be used to transfer materials to the roof, as
an alternative to external scaffolding, in addition I offered to move
ballast to the roof.
After some rather lengthy discussions with the framework manufacturer in Germany and checks by the Engineer the ballast layout was agreed.
The most convenient and economic form of ballast I could find was concrete path edging, 61 were required each weighing 16kg. These were cut as necessary at ground level, carried to 2nd floor and then by an ingenious sledge contraption dragged onto the roof; thanks to Miles, Gillian & Webster for lending a hand!
Safety scaffolding was erected and the installation took a little over a day, the layout fits the roof area neatly with walkways to get to all roof areas.
I am especially pleased with the electrical installation, where
switches, a meter and the large inverter all fit snugly into the available
space next to existing electrical equipment.
Today is the first day of generating electricity, monitored via WiFi and smartphone app.
In a couple of days I will have the necessary paperwork to allow my electricity supplier to pay me every 3 months depending on electricity generated...... after I have paid for the installation.
No comments:
Post a Comment