This pressure equipment shall be considered as a heat exchanger containing super-heated or hot water (with or without additives)
Only when a solar panel in its entirety is designed to withstand the highest possible temperatures (stagnation conditions are within the normal operation range), a risk of overheating does not occur (see PED Guideline B-22). As a consequence the classification shall be made using table 2, Annex II (see PED Guideline B-13).
See also PED Guideline B-04.
Note:
A typical solar panel would be classified as Article 4, paragraph 3 equipment, due to the maximum allowable pressure and volume.