Solar Gone Vertical! Future of verticality is here now...

Flat roofs are more and more ?trendy“ in today′s architecture. It is not only a subject of design. Flat roof can serve for various purposes. Creating a top-floor pool, bar or terace sounds attractive. However, there are other things what to do with flat rooftop. Create a park, relax area, or plant all kinds of vegetation. Such roofs benefit from its cooling effect during hot days. How it goes with PV? The structures are frequently complicated. Most of the cases require additional balast due to the wind-load. In addition, contractors try to avoid any sort of drilling holes into the flat roof. How about if I tell you that there is a solution available?! It is functional, unique, sexy & with number of advantages – vertical PV.

As you might have noticed already, I rarely promote specific companies. I avoid product-placement advertisments as much as I can. The only exceptions are introductions of new concepts. Applications and solutions which step out of the common practice. Those, who guide our mind towards creative direction. OverEasy is one of them. No fear to challenge traditional concepts. Let′s take a look, what makes their solution unique!

?Want to boost your winter PV production? ...harvest your sunrise too!

Traditional PV has one disadvantage. Their sun-harvest is the highest in the moments, when the demand is the lowest. Vertical concept captures sunlight at more optimal angles during peak usage times. Mornings and evenings. Increasing the energy production in those times.

Take a look onto the graph. See the comparison against conventional solution. Of course, it is not identical for all the applications. It is very much region-related. Each project is operating under different circumstances. Make sure to ask for a real simulation for your respective project.

Not only mornings & evenings play the role! Have you ever thought of the seasonality effect? For sure, shorter days don′t allow us to harvest as much in the winter time. It′s not about the time span only. The winter albedo is far away from summer time. Here comes the verticality! In addition to that, snowy surface reflections boost energy outputs further. Summer months are somehow equalized. Winter, spring and fall seasons show significant differences in sun-harvest though. See a comparison chart for your reference. Bear in mind that this chart will be different for each project. Invest the efforts to calculate for your respective location!

Verticality has significant advantages not only while the roof is covered by snow. We also can′t forget about soiling. This phenomenon is significantly reduced on the vertical panels. In comparison with the angeled/flat installations, cleaning is easier too.

Construction with an ease

Freestanding construction elements do not require any mechanical anchoring to the roof structure. No additional weight ballast. Load of the roof can be an issue in many older buildings. Weight of the PV system + the ballast weight might be simply too much. OverEasy concept works with a feather-like weights. Additional load to the roof stays at 11kg/m3. This means no damaging pressure points. No intrusive fasteners that might damage the integrity of the roof over the time. The unique structure is easy to install, move (if needed) and maintain. Does it sound like a theoretical advantage? Your PV shall remain functional for decades. Moving, dismantling, repairing or adjusting just about anything on the roof (or the PV installation) happens once in a while. Being challenged with the construction elements of the PV array is not only complicated. Also time consuming. It will cost you more money, than what you ever thought of.

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Weather is Enemy

It is stormy day. Billboards along the roads are flying through the air. Trees suffer. Many of them break apart. Rooftiles are like dangerous missles. Damaging just about anything what is crossing their path. Whatever the wind did not manage to destroy, the hail will do! Car windows, bus stops, greenhauses in the gardens, and of course solar panels. Truly apocalyptic imagination. It is not an imagination only though! Perfect PV system shall have a lifetime of at least 1/3 of human life. How many times have you experienced hail and/or really strong storm winds? Once in a while, right? The risk of strong winds or hail does not exist on the paper only. It is a real threat for your solar system.

Institut für Industrieaerodynamik - Aachen University of Applied Sciences has computed an effective wind load data in accordance with standard EN 1991-1-4 for this purpose. I do not want to bother with complicated characteristics of the terrain descriptions, nor building parameters at this point. Frauenhofer ISE has also done a computational simulation of a fullscalle installation with wind speed up to 47m/s (33m/s is the hurricane level already) without any additional ballast. In addition, due to the vertically mounted panels, there is no horizontal load relevant. This means there is no additional ballast requirement either.

There were over 250 measurements done in total. Very different circumstances have been simulated. Different building heights. Different parapet sizes. Creating turbulence. Vortex shifts. The results would differ by those factors.

?There are many safety factors taken into consideration. Local circumstances will always determine the number of units needed to be connected together in order to consider those as ballast free. Generally, we could say that majority of urban buildings with 5kWp or more will remain ballast free. See 1 unit design picture.

Hail test has been performed by the Frauenhofer Institute for Solar Energy Systems. It was based on the requirements of the IEC standard 61215. The test sequence is very sophisticated. Not only the ice-balls are shot on the modules, but also, an additional weight is applied in order to simulate strong winds. Those are typically following the hail in real life.

I will explain the hail test procedure is some of the future posts. It is a really interesting one. Iceball with a diameter of 25mm are shot from a cannon towards the module in various locations with a speed of 23m/s. The PV panels are being checked throughly before the test. Then compared with the condition after the hail test. Exactly in the way, which is required by the standard.

No surprise. Those panels withstand the hail test in full. Don′t expect the results as for granted. – Many conventional modules wouldn′t by far pass those tests!

Green Roof & Vertical PV. A Perfect Match!

Love the idea of a green roof but worried about it′s compatibility with PV? Vertical PV modules are the right answer. They seamlessly integrate with roof vegetation. They allow plants to thrive while maximizing your energy production. It is a win-win for sustainability & aesthetics!

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So what you think?

Did the concept draw your attention?

Would you consider verticality as an attractive solution for modern rooftops?

Share your impression!