Header Image SPF Testing Solarglas

More info about Solar Glass – Certification

SPF has developed two certification procedures specially tailored for solar glass.
These procedures include special requirements with regard to the optical properties of solar glass for the two specific applications.

  • Solar Thermal collectors (ST):
    Glass as a transparent cover of insulated solar thermal collectors with a selective absorber.
    Classes U, Y and X
  • PhotoVoltaic modules (PV):
    PV modules composed of cells made of crystallin silicon directly laminated to the solar glass.
    Classes P and R

For the purposes of a certification adapted one of the above mentioned application, solar glass is graded into different performance classes according to a specially defined glass efficiency value ηGL,ST or ηGL,PV. The following factors are taken into account in the determination of the aforementioned glass efficiency value:

Optical transmission, incident angle modifier and degradation (transmission reduction due to environmental factors), which are measured and rated according to the specific application.

The idea behind it is that when a glass is replaced with another glass in the same performance class no loss of performance should be experienced in the collector or the module.

Glass efficiency and classification into performance classes Solar thermal (ST)

AR treated glasse
    Both sides
AR treated glasses
class U1ηGL ≥ 0.900 class Y1ηGL ≥ 0.925 class X1ηGL ≥ 0.950
class U2ηGL ≥ 0.885 class Y2ηGL ≥ 0.910 class X2ηGL ≥ 0.935
class U3ηGL ≥ 0.870 class Y3ηGL ≥ 0.895 class X3ηGL ≥ 0.920
class U4ηGL ≥ 0.850 class Y4ηGL ≥ 0.870 class X4ηGL ≥ 0.890
No solar glassηGL < 0.850 no solar glassηGL < 0.870 no solar glassηGL < 0.890

Glass efficiency and classification into power classes Photovoltaics (PV)

AR treated glasses
class P1ηGL ≥ 0.940 class R1ηGL ≥ 0.980 class P CηGL > 0.0
class P2ηGL ≥ 0.925 class R2ηGL ≥ 0.965   
class P3ηGL ≥ 0.910 class R3ηGL ≥ 0.950   
class P4ηGL ≥ 0.890 class R4ηGL ≥ 0.925   
no solar glassηGL < 0.890 no solar glassηGL < 0.925