Solar Simulation ASTM / IEC / JIS Testing Standards Solar simulation is much more than just choosing a lighting source with a spectrum that "looks good". The whole premise behind simulation of solar energy is to replicate, as accurately as possible, the effects of actual sunlight on products or PV material. Whether you are trying to measure the detrimental effects of UV or the beneficial output of PV panels, this data must parallel the results from actual sunlight and be repeatable. For this reason, international standards have been developed to benchmark solar simulation lighting. International Standards for Solar Simulation Performance There are three categories that are used to classify solar simulation systems; Spectral Concurrence (matching), Irradiation Non-uniformity, and Temporal Instability. Three classes are defined for each of these categories; Class A, Class B; and Class C. A simulation system is rated with three letters, based on its performance to the defined classifications for each of the three categories. The first letter corresponds to spectral matching, the second letter to irradiation non-uniformity, and the third to temporal stability. As an example, a particular simulation system may have a classification of BBA; signifying it has a spectral match equal to Class B, irradiation non-uniformity in the test area of Class B, and temporal stability equal to Class A. Below are the classification parameters for large area simulators from the three major standards organizations. Performance
Parameter | Standards Organization | | ASTM | IEC | JIS | | Spectral match | | | | | Class A | 0.75-1.25 | 0.75-1.25 | 0.75-1.25 | | Class B | 0.6-1.4 | 0.6-1.4 | 0.6-1.4 | | Class C | 0.4-2.0 | 0.4-2.0 | 0.4-2.0 | | Irradiation non-uniformity | | | | | Class A | ≤ 3% | ≤ 2% | ≤ 2% | | Class B | ≤ 5% | ≤ 5% | ≤ 3% | | Class C | ≤ 10% | ≤ 10% | ≤ 10% | | Temporal instability | | | | | Class A | ≤ 2% | ≤ 2% | ≤ 1% | | Class B | ≤ 5% | ≤ 5% | ≤ 3% | | Class C | ≤ 10% | ≤ 10% | ≤ 10% |
| |
Global Reference Spectral Irradiance Standard
The reference spectral distribution of sunlight at Air Mass 1.5 Global is defined in ASTM G173-03 and IEC 60904-3. For classification of solar simulation systems, this standard is restricted to the wavelengths from 400 nm to 1,100 nm. This defined spectral bandwidth is then divided into six (6) wavelength bands. Each of these six wavelength bands is assigned a particular percentage of the total integrated irradiance (reference IEC 60904-9; ASTM E927-05). The spectral match of a simulation system is classified (see above) based on its performance with respect to each of these six reference bands. The spectral classification (A, B, or C) of a simulation system is equal to the worst case match to any of the six reference wavelength bands. For example, if a simulation system matches the five waveband specification ranges from 500nm to 1,100nm within 0.75-1.25 (Class A) but only matches the 400nm-500nm wavelength band within 0.55 (Class C) of the specified irradiance, the system spectral concurrence must be classified as Class C overall. For an actual light source test example, see section on Choosing Price / Performance To Fit Your Application. Wavelength
Band | Bandwidth | Percentage of total irradiance
(400nm - 1,100nm) | | 1 | 400 - 500 | 18.4% | | 2 | 500 - 600 | 19.9% | | 3 | 600 - 700 | 18.4% | | 4 | 700 - 800 | 14.9% | | 5 | 800 - 900 | 12.5% | | 6 | 900 - 1,100 | 15.9% |
| |
|
|
