Renewable Energy Sources for the mCCHP-SE-RES Systems - Design for Micro-Combined Cooling, Heating and Power Systems - page 95

Fig. 3 EU Solar energy potential [ 8 ]

2.1 The Principle of Solar Energy Conversion

Solar irradiation is made up of photons with different energies. When absorbed by a
material, they transfer their energy. The individual energy of a photon is directly
linked to a certain characteristic, namely the wave length. To a smaller wave length
corresponds a greater energy. Any photon transfers its energy, completely or not. The
energy transfer from the photon to the material is called absorption (Fig. 4 ). If the
photon is not completely absorbed, two types of interaction may be distinguished:

the photon passes though the material (transmission);

￿

￿ the photon is re ected by the material ' is surface (re ection).

Fig. 4 The interaction of light with the illuminated body