Solar simulator

A solar simulator (also artificial sun) is a device that provides illumination approximating natural sunlight. The purpose of the solar simulator is to provide a controllable indoor test facility under laboratory conditions, used for the testing of solar cells, sun screen, plastics, and other materials and devices. A solar simulator (also artificial sun) is a device that provides illumination approximating natural sunlight. The purpose of the solar simulator is to provide a controllable indoor test facility under laboratory conditions, used for the testing of solar cells, sun screen, plastics, and other materials and devices. The IEC 60904-9 Edition2 and ASTM E927-10 standardsare a common specification for solar simulators used for photovoltaic testing. The light from a solar simulator is controlled in three dimensions: Each dimension is classified in one of three classes: A, B, or C. The specifications required for each class are defined in Table 1 below. A solar simulator meeting class A specifications in all three dimensions is referred to as a Class A solar simulator, or sometimes a Class AAA (referring to each of the dimensions in the order listed above). The solar simulation spectrum is further specified via the integrated irradiance across several wavelength intervals. The percentage of total irradiance is shown below in Table 2 for the standard terrestrial spectra of AM1.5G and AM1.5D, and the extraterrestrial spectrum, AM0. These specifications were primarily intended for silicon photovoltaics, and hence the spectral range over which the intervals were defined was limited mainly to the absorption region of silicon. While this definition is also adequate for several other photovoltaic technologies, including thin film solar cells constructed from CdTe or CIGS, it is not sufficient for the emerging sub-field of concentrated photovoltaics using high-efficiency III-V semiconductor multi-junction solar cells due to their wider absorption bandwidth of 300–1800 nm. Solar simulators can be divided into three broad categories: continuous, flashed, and pulsed. The first type is a familiar form of light source in which illumination is continuous in time. The specifications discussed in the previous section most directly relate to this type of solar simulator. This category is most often used for low intensity testing, from less than 1 sun up to several suns. In this context, 1 sun is typically defined as the nominal full sunlight intensity on a bright clear day on Earth, which measures 1000 W/m2. Continuous light solar simulators may have several different lamp types combined (e.g. an arc source and one or more halogen lamps) to extend the spectrum far into the infrared. Examples of low-intensity and high-intensity continuous solar simulators are available from Solar Light Company, Inc. (inventor of the original solar simulator in 1967,) Atonometrics, Eternal Sun, TS-Space Systems,WACOM, Newport Oriel, Sciencetech, Spectrolab, Photo Emission Tech,Abet Technologies, infinityPV The second type of solar simulator is the flashed simulator which is qualitatively similar to flash photography and use flash tubes. With typical durations of several milliseconds, very high intensities of up to several thousand suns are possible. This type of equipment is often used to prevent unnecessary heat build-up in the device under test. However, due to the rapid heating and cooling of the lamp, the intensity and light spectrum are inherently transient, making repeated reliable testing more technically challenging. The temporal stability dimension of the standard does not directly apply to this category of solar simulators, although it can be replaced by an analogous shot-to-shot repeatability specification.