Solar radiation durability framework applied to acrylic solar mirrors

Abstract

Mirror augmented photovoltaic (MAPV) systems utilize low cost mirrors to couple more light into a photovoltaic (PV) absorber. By increasing the light absorbed, they are expected to produce less expensive electricity. As a substrate candidate for back surface reflector mirrors, two grades of PMMA have been exposed to UV stress from two sources at two intensities for two doses in an effort to see the response of materials under different states of stress and after exposure to different amounts of total stress. By developing a framework for correlating stresses, such as short wave ultraviolet radiation, with responses, such as induced absorbance and yellowing, mirror durability we have made progress in developing lifetime and degradation science using mirror durability as a case study. All of the samples showed similarities in their degradation characteristics. The UV stress acceleration factor was quantized as 10.2 in short wave ultraviolet irradiance, and 15.8 in total shortwave UV dose. The effects of UV absorbers in protecting the polymer from degradation are discussed. Further study into degradation mechanisms will elucidate the exact phenomena that contribute to these material responses to stress.

Statistical and Domain Analytics Applied to PV Module Lifetime and Degradation Science

“…The number of measurements at each time point for each variable is not consistent. Some variables were measured multiple times (2)(3)(4)(5)(6) per disassembled module at each time point, while others were only measured once. Additionally, individual measurements at identical time points between different variables are only comparable to one another on the basis of their sample origin (which module they came from), and do not correspond directly to one another even if the number of measurements is identical.…”

“…A recent U.S. Department of Energy workshop on Science for Energy Technologies [1] identified photovoltaics (PV) lifetime and degradation science (L&DS) [2]- [4] as a critical scientific challenge for robust adoption of PV. The PVQA Task Force was developed as an international task force to work towards defining what is needed for lifetime qualification standards and tests [5].…”

Durability of acrylic: Stress and response characterization of materials for photovoltaics

“…A Stress and Response Framework [13] is used to quantify damaging environmental stress and correlate those stresses to material responses. Stressors that impact PV materials and components can be characterized in terms of instantaneous stress level ( ), and net stress or integrated stress (S), which is the instantaneous stress level integrated over the length of time the stress was applied (Equation 1).…”

Global SunFarm data acquisition network, energy CRADLE, and time series analysis

“…The prediction of lifetime and R d with new technology insertion requires a better understanding of the degradation mechanisms of PV systems, components and materials. A stress-response framework was developed [3] and applied to the indoor accelerated test of back surface acrylic mirrors [4]. This method can also be used for outdoor testing of PV to quantitatively determine its performance in the real world.…”