The initial results for our performance testing are in and so far it is looking both good, and a bit inconclusive. As reported we started measuring at the end of March. The first parameter I am looking at is air temperature, for solar panels placed on a normal roof (first) and on a blue-green roof (second, photo taken when still under construction).
The hypothesis is that a blue-green roof with solar panels is cooler during sunshine than a roof with only solar panels. Keep in mind that solar panels operate at best performance at 25◦C. Especially during summer, the cooler temperature will lead to higher performance for the solar panels with blue-green roofs due to evapotranspiration from the vegetation. This is the theory, so let's see what happens in practice.
On the 17th of April at 15:00 we get these example results:
Sensor 1 is above solar panels with blue-green roof, 2 below. 5 above solar panels, 6 below. Expected temperatures from high to low: 5 > 1 and 6 > 2
If we expand the time series for more inputs we consistently see 6, below the regular solar panels, having the highest extreme temperatures. It is closest to the black flat roof and there might be less wind under the solar panels, thus increasing the heat during the day.
Examining this more closely for a single day, we see the following:
From this we can conclude that the location below the solar panels (6) is consistently the most extreme hot and cold; Next most extreme is 2 (below solar panels with blue-green roofs. The largest difference between these locations so far has been 5.8 degrees during sun hours and 3.5 degrees during nighttime hours.
Above solar panels with blue-green roofs (1) and above solar panels (5) are difficult to distinguish on a day-to-day basis. The exact impacts should become clearer over time.
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