Solar irradiance tests

The above-mentioned codes contain requirements for accelerated durabiUty tests. In addition, interlayer manufacturers and laminators expose test samples for several years under extreme weather conditions, eg, the Florida coast and Arizona desert. The laminated products weather extremely well, with no change in the plastic interlayer. Occasionally, clouding is noted around the edges when exposed to high humidity for long periods, but this is reversible. Colored areas of PVB laminates may fade while subjected to extensive uv/solar irradiation, which could cause an appearance issue. This has not, however, been shown to alter the laminate s other performance properties. 

Warnings are often given that acceleration factors for relating artificial light sources with service are meaningless, because of both the variation in solar irradiation and the variation in spectral distribution. Regardless of this, acceleration factors are estimated, and indeed have to be if any extrapolation from accelerated tests is to be made. 

In addition to the above, the reduction in treatment time with concentration is also an attractive feature of the 2 suns collector, in spite of the fact that it misses aroimd 25% of the available radiation. Due to the abundance of solar irradiation in the test site (Temixco, Morelos, Mexico), it does not appear that sacrificing a part of the UV radiation is such a great concern. However, in depth techno-economic analyses are required to support this assertion. 

Hypotheses were set to investigate whether dyed photochromic polyamides had properties of both a UV sensor and a shielding material against solar irradiance. To test the hypotheses, knitted polyamide fabric was dyed with the following dyes ... 

Textile membranes are exposed not only to mechanical stresses but also to various environmental influences. The main damaging influences are temperature, humidity, solar irradiation, noxious industrial gases, ozone, dust, salts and micro-organisms. These influences impair the functional properties, performance and life-span of the membranes. DIN EN ISO 4892 standard describes the basics for these tests. It is expected that textile membranes should last for decades without their properties and performance being compromised. However, every year many materials break down due to severe environmental influences and cause damage worth millions of euros. 

The ultimate test for any photoelectrochemical device or individual photoelectrode is its performance under solar irradiation. Since few places in the world have daily access to sunlight of a constant intensity, most PEC research laboratories are equipped with a solar simulator. Figure 3.4 shows an overview of the main components for a photoelectrochemical experimental test setup feamring simulated sunlight. A potentiostat is used to control the sample s potential and to measure... 

Black Box under Glass Exposures. These tests were designed to simulate and accelerate the effect of interior automotive conditions. Air temperatures in the box may exceed 80°C under conditions of high outside ambient air temperature and solar irradiance. Exterior nonglass surfaces are painted flat black and interior surfaces are left unpainted. The specimens, supported on a rack in a plane parallel... 

Nevertheless, all is not solved. Microscopic observation of the surfaces of the weathered PET films revealed changes in chemistry and micro-cracking due to weathering that were not identical in both the laboratory test method and outdoor exposure. In particular, the FTIR spectrum of the surface of the PET sample exposed in Rorida revealed generation of chemical species that were not reproduced via the laboratory test. Even orientation of a sample can affect synchronization of failure modes by altering the relative amounts of solar irradiance and water to which the specimen may be exposed. 

Different test sites (see Fig. 13.1) have been equipped with instrumentation for monitoring the climate. The solar irradiance was measured by calibrated pyranom-eters, UV-A, UV-B with integral sensors and the wind velocity and direction with anemometers 3 m above ground. The module temperatures were measured at the... 

Real weathering loads on contemporary vehicles cannot be simulated in an accelerated test. Depending on the task, a large number of very different tests are applied. The most important test is artificial weathering and simulated solar irradiation, s. Section 2.2.4.2. Investigations for BMW, for example, showed that 240 hours of sunlight simulation are sufficient to obtain reliable predictions for component lifetime. However, it is decisive that the component test be performed under actual service conditions for the vehicle [203]. 

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