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SolarTown Learning

Sanyo Bifacial Solar Panels – A New Approach to Extracting More Energy from your Rooftop

01-13-2010
Category: Solar Panels

You thought that the Sanyo bifacial panels could only be used for certain applications, like porches, awnings and carports.  But now think again. In Ontario, Canada, one company found a creative way to apply the Sanyo bifacial panel to a flat roof and extract even more energy from the installation. Take a look at this photo from Sanyo showing how the bifacial solar panels have been applied to overhangs such as a awning.

Sanyo Bifacial Solar Panels

Sanyo bifacial panels generate power from the front and backside. Sanyo's solar panels increase power output by using ambient light surrounding the panel and not just direct light hitting the panel. Bifacials are not flush-mounted.

The Sanyo Bifacial Panel on a Flat Roof

The DuROCK Alfacing International Manufacturing Company has taken this concept one step further. The Company has  combined its Tio-Coat reflective roofing with a 10 kW array on the company headquarters in Woodbridge, Ontario. 

By installing Sanyo 195 HIT doubles on top of the Tio-Coat surface the Company has increased the solar irradiance on the roof while simultaneously reducing the cooling load used by the building. Sanyo Bifacial Solar Panel on Flat RooftopThe reflective roof generates more solar radiation than conventional asphalt or tar-based materials in addition to lowering the heat load. Standard Test Conditions indicate Sanyo's HIT double panels can yield up to 30% more output than a conventional similarly rated panel. What is unknown in this scenario is how much additional insolation is available as a result of the reflective material used on the roof.

The Details of the Installation

The 10kW system is comprised of 51 Sanyo 195 HIT modules mounted at a 30-degree angle on a flat commercial building. The system uses three Sunny Boy 4000 inverters with two strings of 18 panels (6+6+6 in series) and one string of 15 (5+5+5). The inverters were oversized to compensate for the increased irradiance. The Sanyo solar modules were chosen for their bifacial qualities, and the 30 to 35 degree tilt is common in this part of Canada. While tilted less than latitude, installers have been mounting arrays at this angle to minimize wind load issues. The modules are mounted in two rows about a foot off the ground, and are also ballasted, so there are no roof penetrations. In this manner they'll encourage snow melt-off, maximize summer power generation, and minimize shading issues within and between module rows.

Does Extra Cost Justify the Additional Output?

Is it worth it? With solar modules representing the lion's share of an array investment, DuROCK is betting the extra cost is well worth the price. At the opening, representatives from both Sanyo and DuROCK were smiling. Ontario Solar Installation with Sanyo Bifacial Panels

Sanyo's solar modules deliver at or above stated nameplate power ratings (0 / + 10 watts) and are 16.7% efficient, so system owners understand the payback from the outset, not after the panels are installed. These bifacials deliver 195 - 210 watts. What is so exciting about this installation is the integrated approach - no one really knows how much more power will be made by integrating the reflective roof. One thing is certain though, SolarTown will be continuing to follow these developments closely.


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