The present work addresses a flat plate solar collector with transparent insulation material (TIM) and high temperature protection system. The design and optimization of the collector have been numerically carried out by means of a parallel object-oriented simulation tool which is capable of simulating all the entities constituting the system as a whole, using efficient coupling between the elements. Three variants of the design are chosen to first test them under laboratory conditions. These collectors then are mounted in the roof of a hospital building, where their performance are comparatively tested along with a conventional flat plate solar collector, under real meteorological conditions and during long periods of time. Thus, due to long term exposure of the collectors, aspects such as reliability, durability, energy performance, correct functioning of the protection system will be analyzed, with the objective of improving the detected shortcomings for the future generations of the present design.