Solar Decathlon Europe (2012) was home to houses run by a variety of solar technologies, much like the United States Decathlon will be in October 2013. Which panels or systems are most appropriate is debatable. Some systems were smaller, but more efficient and more costly. Others were more basic, but less expensive. Here are a few of the techniques which were used to create more efficient systems or systems with greater output:
Both Tonji Team (ParaEcoHouse) and Antonyshine Team (Antonyshine House) have tracking systems. Tonji Team has traditional monocrystalline PV panels mounted on a system which rotated them to be perpendicular to the sun’s rays as the sun moves across the sky, maximizing the amount of light that can hit the surface of the panel, and therefore also maximizing the amount of energy that can be produced. Antonyshine combines tracking system with a concentrating mirror technology. The system was created by the team and uses only a small strip of monocrystalline silicon receiver to produce power.
It could be argued that the CEM + NEM Team (Casa Movimento) used a PV system with a similar idea behind it to the tracking system, though it was not strictly a tracking system itself. The entire system was on a frame of its own, attached to a hydraulic pump . This allows the entire exterior PV-clad frame to rotate and slide out from its place directly over the house. There are a variety of purposes for this, one of which is rotating to increase the efficiency during all seasons of the year.
Though all of these systems are more expensive than simple, fixed, flat panels, they produce a larger amount of power, which theoretically offsets the difference in costs of the systems.
As previously explained, the Astonyshine House (Astonyshine Team) uses a curved mirror system to concentrate the amount of light which hits the monocrystalline silicon receiver. The Sumbiosi House (Aquitaine Bordeaux Campus Team) similarly concentrated light, but those systems used lenses instead of mirrors. The sun’s rays are concentrated by 500 times onto polycristalline silicon panels.
It’s easy to understand the reasoning behind installing systems which have additional parts that increase the efficiency of photovoltaic panels: they take up less space, and they are (usually) cost-effective than plain PV panels.
Adding vertical panels to a system of photovoltaics is about increasing output, but without concern about cost or how much each panel is actually producing. Both the CEU Valencia Team (SMLSystem) and CEM + NEM (Casa Movimento)used vertically installed panels to increase their overall system size. Their systems are, respectively, 7.2 kWh and 9.24 kWh.
Personally, I believe that though they may add to the system size, the vertical panel – unless specifically designed for vertical installation – is ultimately an inelegant, inefficient solution to making increasing the size of a system. Other techniques of increasing a system’s, such as the mirrors and lenses used or the tracking systems, size are a far more effective use of materials and money.