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Consumer Co-op Realizes Mega Solar Systems on Logistics Facilities (page 3)

High yield using Japanese panels, PV inverters

2014/03/31 15:23
Kenji Kaneko, Nikkei BP CleanTech Institute
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However, Osaka Izumi Co-op was the first institution to which Tess Engineering ever provided EPC service for a mega-solar power plant with an output exceeding 1MW. Tess Engineering chose Kyocera's solar panels because of their past accomplishments after examining mainly domestically produced products (Fig. 3). Tess Engineering said it also adopted TMEIC's PV inverters as it highly appreciated TMEIC's broader lineup compared with other manufacturers of large PV inverters, their reliability and accurate delivery time (Fig. 4).

1MW achieved by spreading panels across roof

Although this was the first mega-class facility for Tess Engineering to deal with, it had previous experience in many designs that directly set up solar panels on folded-plate roofs using clasps. The form of foldings in the folded-plate roof had been standardized, and the clasps to hold parts and materials to the roof were also general-purpose ones.

Based on the calculated clasp strength and resistance to wind pressure, four to six clasps were used to hold each panel (Fig. 5). Tess Engineering said that considering the panels, cables and other facilities installed on the roof, which weigh 21kg per 1m2, the roof had sufficient strength.

All across the roof of Ayumino Logistics Center, you can see the solar panels beautifully arrayed. The roof is almost exactly the right size for 1MW worth of solar panels. Accordingly, the roof gives the impression that it is almost completely covered with panels. Unlike most other blue polycrystalline silicon panels, Kyocera's panels look blackish due to their proprietary surface finishing technology, which is aimed at preventing reflection. The appearance of the roof, covered in chic black, is magnificent (Fig. 6).

At a glance, the panels appear to be set up flat, but in fact they are tilted at 2 to 3°. The folded-plate roof was originally tilted at 2 to 3° with the aim of making rainwater drain off. As the panels are directly secured to the tilted roof, they are also tilted at the same angle that efficiently drains rainwater. Since Kyocera's panel design sets slits on the edge of the frame so that rainwater can easily drain off with any dirt, it is suited to an installation at such a low angle.

Amount of annual power generation exceeds expectations by 1.3 times

What became an issue when starting construction in July was the heat. The temperature of the steel plate used for the folded-plate roof exceeds 70°C under the sun during the day, with the ambient temperature nearly reaching 50°C. Working for hours on the roof under these circumstances could cause heatstroke.

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