PHOTOTHERMAL TRANSFORMATION
Is the transformation produced and used in some materials which increase the temperature when the solar radiation touch it. We classified this thermal effect with the thermal level (high, medium and low temperature) depending of the dispositives used.

Medium and High temperature:
The uses of direct and not diffuse solar energy like energetic resources is submitto an strong advance during the last decade. There are some systems, although all the systems ared based in the solar energy concentration:

-Distribuited captor system with cilindric-parabolic concentrator.
-System with central tower and heliostate concentrator.
-Parabolics disk System.

In Spain there are some iniciatives with distribuited and central tower systrems.

Low Temperature:
These are the applications which use temperatures from 60 to 80ºC; We can distinguish the active and passive systems.

The active systems use plane captors and the principal application is for domestic hot water, hot water for industrial systems, hot water for swimming pool, heating and air conditioning, heating for drying room, et cetera...

The passive systems has the principal application in the architecture than use the geothermal and thermal qualities of building materials taking the solar radiation.